WorldWideScience

Sample records for catalytic water co-existing

  1. Glycol-Water Interactions and co-existing phases and Temperature Dependent Solubility. An Example Of Carbon-Hydrogen Chemistry In Water

    CERN Document Server

    Michael, Fredrick

    2010-01-01

    Recently there has been great interest in Glycol-Water chemistry and solubility and temperature dependent phase dynamics. The Glycol-Water biochemistry of interactions is present in plant biology and chemistry, is of great interest to chemical engineers and biochemists as it is a paradigm of Carbon-Hydrogen Water organic chemistry. There is an interest moreover in formulating a simpler theory and computation model for the Glycol-Water interaction and phase dynamics, that is not fully quantum mechanical yet has the high accuracy available from a fully quantum mechanical theory of phase transitions of fluids and Fermi systems. Along these lines of research interest we have derived a Lennard-Jones -like theory of interacting molecules-Water in a dissolved adducts of Glycol-Water system interacting by Hydrogen bonds whose validity is supported at the scale of interactions by other independent molecular dynamics investigations that utilize force fields dependent on their experimental fittings to the Lennard-Jones ...

  2. Biogeochemical redox cycling of arsenic in mine-impacted lake sediments and co-existing pore waters near Giant Mine, Yellowknife Bay, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, C.F. [Queen' s University, Department of Geological Sciences and Geological Engineering, Kingston, K7L 3N6 (Canada); Jamieson, H.E., E-mail: jamieson@geol.queensu.ca [Queen' s University, Department of Geological Sciences and Geological Engineering, Kingston, K7L 3N6 (Canada); Kyser, T.K. [Queen' s University, Department of Geological Sciences and Geological Engineering, Kingston, K7L 3N6 (Canada); Praharaj, T.; Fortin, D. [University of Ottawa, Department of Earth Sciences, Ottawa, K1A 3N5 (Canada)

    2010-02-15

    Lacustrine sediments, submerged tailings, and their pore waters have been collected at several sites in Yellowknife Bay, Great Slave Lake, Canada, in order to investigate the biogeochemical controls on the remobilization of As from mining-impacted materials under different depositional conditions. Radiometric dating confirms that a mid-core enrichment of Pb, Zn, Cu and Sb corresponds to the opening of a large Au mine 60 a ago. This was evident even in a relatively remote site. Arsenic was enriched at mid-core, coincident with mining activity, but clearly exhibited post-depositional mobility, migrating upwards towards the sediment water interface (SWI) as well as down-core. Deep-water (15 m) Yellowknife Bay sediments that contain buried mine waste are suboxic, relatively organic-rich and abundant in microbes with As in pore waters and sediments reaching 585 {mu}g/L and 1310 mg/kg, respectively. Late summer pore waters show equal proportions of As(III) and As(V) (16-415 {mu}g/L) whereas late winter pore waters are dominated by As(III) (284-947 {mu}g/L). This can be explained by As(III) desorption mechanisms associated with the conversion of FeS to FeS{sub 2} and the reduction of As(V) to As(III) through the oxidation of dissolved sulfide, both microbially-mediated processes. Processes affecting As cycling involve the attenuating efficiency of the oxic zone at the SWI, sediment redox heterogeneity and the reductive dissolution of Fe(hydr)oxides by labile organic matter, temporarily and spatially variable.

  3. Germination sensitivities to water potential among co-existing C3 and C4 grasses of cool semi-arid prairie grasslands.

    Science.gov (United States)

    Mollard, F P O; Naeth, M A

    2015-03-01

    An untested theory states that C4 grass seeds could germinate under lower water potentials (Ψ) than C3 grass seeds. We used hydrotime modelling to study seed water relations of C4 and C3 Canadian prairie grasses to address Ψ divergent sensitivities and germination strategies along a risk-spreading continuum of responses to limited water. C4 grasses were Bouteloua gracilis, Calamovilfa longifolia and Schizachyrium scoparium; C3 grasses were Bromus carinatus, Elymus trachycaulus, Festuca hallii and Koeleria macrantha. Hydrotime parameters were obtained after incubation of non-dormant seeds under different Ψ PEG 6000 solutions. A t-test between C3 and C4 grasses did not find statistical differences in population mean base Ψ (Ψb (50)). We found idiosyncratic responses of C4 grasses along the risk-spreading continuum. B. gracilis showed a risk-taker strategy of a species able to quickly germinate in a dry soil due to its low Ψb (50) and hydrotime (θH ). The high Ψb (50) of S. scoparium indicates it follows the risk-averse strategy so it can only germinate in wet soils. C. longifolia showed an intermediate strategy: the lowest Ψb (50) yet the highest θH . K. macrantha, a C3 grass which thrives in dry habitats, had the highest Ψb (50), suggesting a risk-averse strategy for a C3 species. Other C3 species showed intermediate germination patterns in response to Ψ relative to C4 species. Our results indicate that grasses display germination sensitivities to Ψ across the risk-spreading continuum of responses. Thus seed water relations may be poor predictors to explain differential recruitment and distribution of C3 and C4 grasses in the Canadian prairies.

  4. Co-existence of agricultural production systems.

    Science.gov (United States)

    Jank, Bernhard; Rath, Johannes; Gaugitsch, Helmut

    2006-05-01

    Strategies and best practices for the co-existence of GM and non-GM crops need to be developed and implemented with the participation of farmers and other stakeholders. According to the principle of 'subsidiarity', decisions should be made by the lowest authority possible. When applying this concept to the case of GM crops, the affected society should determine their use and management in a regional decision-making process. Public participation is better accomplished at a lower level, and democratic deficits in decision-making on GMOs are better resolved, enabling farmers to manage or avoid GM crops. Ultimately, voluntary GMO-free zones might be a tool for sustainable co-existence and GM-free production and GMO-free zones might create a specific image for marketing regional products and services, such as tourism.

  5. Water recovery by catalytic treatment of urine vapor

    Science.gov (United States)

    Budininkas, P.; Quattrone, P. D.; Leban, M. I.

    1980-01-01

    The objective of this investigation was to demonstrate the feasibility of water recovery on a man-rated scale by the catalytic processing of untreated urine vapor. For this purpose, two catalytic systems, one capable of processing an air stream containing low urine vapor concentrations and another to process streams with high urine vapor concentrations, were designed, constructed, and tested to establish the quality of the recovered water.

  6. Photolytic AND Catalytic Destruction of Organic Waste Water Pollutants

    Science.gov (United States)

    Torosyan, V. F.; Torosyan, E. S.; Kryuchkova, S. O.; Gromov, V. E.

    2017-01-01

    The system: water supply source - potable and industrial water - wastewater - sewage treatment - water supply source is necessary for water supply and efficient utilization of water resources. Up-to-date technologies of waste water biological treatment require for special microorganisms, which are technologically complex and expensive but unable to solve all the problems. Application of photolytic and catalytically-oxidizing destruction is quite promising. However, the most reagents are strong oxidizers in catalytic oxidation of organic substances and can initiate toxic substance generation. Methodic and scientific approaches to assess bread making industry influence on the environment have been developed in this paper in order to support forecasting and taking technological decisions concerning reduction of this influence. Destructive methods have been tested: ultra violet irradiation and catalytic oxidation for extraction of organic compounds from waste water by natural reagents.

  7. Degradation of Organic Pollutants in Water by Catalytic Ozonation

    Institute of Scientific and Technical Information of China (English)

    LI Xin; YAO Jun-hai; QI Jing-yao

    2007-01-01

    Different series of transition metal catalysts supported on Al2O3 were prepared by the impregnation method. The catalytic activity was measured in a batch reactor with ozone as the oxidizing reagent. The experimental results indicate that Cu/Al2O3 has a very effective catalytic activity during the ozonation of organic pollutants in water. The optimum conditions for preparing Cu/Al2O3 were systematically investigated with the orthogonal testing method. Furthermore, the results also show that the surface properties of catalyst are not compulsory for effective oxidation.

  8. Co-existence of Functionally Different Vesicular Neurotransmitter Transporters.

    Science.gov (United States)

    Münster-Wandowski, Agnieszka; Zander, Johannes-Friedrich; Richter, Karin; Ahnert-Hilger, Gudrun

    2016-01-01

    The vesicular transmitter transporters VGLUT, VGAT, VMAT2 and VAChT, define phenotype and physiological properties of neuronal subtypes. VGLUTs concentrate the excitatory amino acid glutamate, VGAT the inhibitory amino acid GABA, VMAT2 monoamines, and VAChT acetylcholine (ACh) into synaptic vesicle (SV). Following membrane depolarization SV release their content into the synaptic cleft. A strict segregation of vesicular transporters is mandatory for the precise functioning of synaptic communication and of neuronal circuits. In the last years, evidence accumulates that subsets of neurons express more than one of these transporters leading to synaptic co-release of different and functionally opposing transmitters and modulation of synaptic plasticity. Synaptic co-existence of transporters may change during pathological scenarios in order to ameliorate misbalances in neuronal activity. In addition, evidence increases that transporters also co-exist on the same vesicle providing another layer of regulation. Generally, vesicular transmitter loading relies on an electrochemical gradient ΔμH(+) driven by the proton ATPase rendering the lumen of the vesicle with respect to the cytosol positive (Δψ) and acidic (ΔpH). While the activity of VGLUT mainly depends on the Δψ component, VMAT, VGAT and VAChT work best at a high ΔpH. Thus, a vesicular synergy of transporters depending on the combination may increase or decrease the filling of SV with the principal transmitter. We provide an overview on synaptic co-existence of vesicular transmitter transporters including changes in the excitatory/inhibitory balance under pathological conditions. Additionally, we discuss functional aspects of vesicular synergy of transmitter transporters.

  9. Co-existence of functionally different vesicular neurotransmitter transporters

    Directory of Open Access Journals (Sweden)

    Agnieszka eMünster-Wandowski

    2016-02-01

    Full Text Available The vesicular transmitter transporters VGLUT, VGAT, VMAT2 and VAChT, define phenotype and physiological properties of neuronal subtypes. VGLUTs concentrate the excitatory amino acid glutamate, VGAT the inhibitory amino acid GABA, VMAT2 monoamines, and VAChT acetylcholine into synaptic vesicle (SV. Following membrane depolarization SV release their content into the synaptic cleft. A strict segregation of vesicular transporters is mandatory for the precise functioning of synaptic communication and of neuronal circuits. In the last years, evidence accumulates that subsets of neurons express more than one of these transporters leading to synaptic co-release of different and functionally opposing transmitters and modulation of synaptic plasticity. Synaptic co-existence of transporters may change during pathological scenarios in order to ameliorate misbalances in neuronal activity. In addition, evidence increases that transporters also co-exist on the same vesicle providing another layer of regulation. Generally, vesicular transmitter loading relies on an electrochemical gradient µH+ driven by the proton ATPase rendering the lumen of the vesicle with respect to the cytosol positive ( and acidic (pH. While the activity of VGLUT mainly depends on the component, VMAT, VGAT and VAChT work best at a high pH. Thus, a vesicular synergy of transporters depending on the combination may increase or decrease the filling of SV with the principal transmitter. We provide an overview on synaptic co-existence of vesicular transmitter transporters including changes in the excitatory/inhibitory balance under pathological conditions. Additionally, we discuss functional aspects of vesicular synergy of transmitter transporters.

  10. Education for a Culture of Peace and Co-Existence

    Directory of Open Access Journals (Sweden)

    Silvia Guetta

    2016-07-01

    Full Text Available Education is a key and fundamental tool required to achieve social change, especially regarding social cohesion and co-existence. Education affects the most critical issues facing humanity, including the proliferation of various forms of violence, environmental degradation, and annihilation of cultures. I argue that the impact of education is equal to that of economics, politics, and technological advances. Therefore, if we wish to see change, educational reform has to be designed to operate in a global-human context, empowering and allowing people to achieve their potential. It should instil in individuals and groups respect for others with whom they interact, in a global as well as local sense. The article draws on the theories of Edgar Morin, Reuven Feuerstein, and Jerome Bruner, and their contributions to the development of educational approaches that encourage a culture of responsible, participatory, and creative coexistence. .

  11. Co-existence of Pulmonary, Tonsillar and Laryngeal Tuberculosis

    Directory of Open Access Journals (Sweden)

    Erkan Ceylan

    2013-10-01

    Full Text Available    A 56-year old man applied to otorhinolaryngology clinic with sore throat, dysphagia. During direct examination, left palatine tonsil and tonsil plicas ulcerovegetative lesions were found. In the indirect laryngoscopy, in some regions of the larynx and epiglottis, ulcerovegetative lesions were observed too. Because of suspicion of laryngeal carcinoma and metastasis, punch biopsy of the left palatine tonsil was performed. Chest x-ray and computerized tomography of the thorax revealed two adjacent cavitations in the apicoposterior segment of the left upper lobe. In the histopathologic examination of biopsies, granulomatous structures that proved tuberculosis were observed. In the fiberoptic bronchoscopic analysis, endobronchial lesion was not detected. Acid-fast bacilli were determined in sputum and bronchial lavage in microscopy and culture. The case of this middle aged male patient with co-existence of tonsillar, laryngeal and pulmonary tuberculosis presents the clinical significance of upper airway tuberculosis in terms of its infectiousness and rare occurrence.

  12. Preparation of improved catalytic materials for water purification

    Science.gov (United States)

    Cherkezova-Zheleva, Z.; Paneva, D.; Tsvetkov, M.; Kunev, B.; Milanova, M.; Petrov, N.; Mitov, I.

    2014-04-01

    The aim of presented paper was to study preparation of catalytic materials for water purification. Iron oxide (Fe3O4) samples supported on activated carbon were prepared by wet impregnation method and low temperature heating in an inert atmosphere. The as-prepared, activated and samples after catalytic test were characterized by Mössbauer spectroscopy and X-ray diffraction. The obtained X-ray diffraction patterns of prepared samples show broad and low-intensity peaks of magnetite phase and the characteristic peaks of the activated carbon. The average crystallite size of magnetite particles was calculated below 20 nm. The registered Mössbauer spectra of prepared materials show a superposition of doublet lines or doublet and sextet components. The calculated hyperfine parameters after spectra evaluation reveal the presence of magnetite phase with nanosize particles. Relaxation phenomena were registered in both cases, i.e. superparamagnetism or collective magnetic excitation behavior, respectively. Low temperature Mössbauer spectra confirm this observation. Application of materials as photo-Fenton catalysts for organic pollutions degradation was studied. It was obtained high adsorption degree of dye, extremely high reaction rate and fast dye degradation. Photocatalytic behaviour of a more active sample was enhanced using mechanochemical activation (MCA). The nanometric size and high dispersion of photocatalyst particles influence both the adsorption and degradation mechanism of reaction. The results showed that all studied photocatalysts effectively decompose the organic pollutants under UV light irradiation. Partial oxidation of samples after catalytic tests was registered. Combination of magnetic particles with high photocatalytic activity meets both the requirements of photocatalytic degradation of water contaminants and that of recovery for cyclic utilization of material.

  13. Sheehan's syndrome co-existing with Graves' disease.

    Science.gov (United States)

    Arpaci, D; Cuhaci, N; Saglam, F; Ersoy, R; Cakir, B

    2014-01-01

    Sheehan's syndrome (SS), which is an important cause of hypopituitarism, is common in developing countries. The most common presentation is the absence of lactation and amenorrhea. Hypothyroidism rather than hyperthyroidism is the usual expected phenomenon in SS. Postpartum hyperthyroidism is also common and Graves' disease (GD) is an important cause of postpartum hyperthyroidism. Here we report a case of a 22-year-old female patient in our clinic presented symptoms of amenorrhea, lack of lactation, palpitations and sweating. Her physical examination revealed goiter, moist skin and proptosis. Her laboratory evaluation showed suppressed thyroid stimulating hormone, elevated levels of free thyroxine and free triiodothyronine. Thyroid antibodies were positive. Tec 99m thyroid scintigraphy results were gland hyperplasia and increased uptake consistent with GD. She gave birth 7 months ago; after delivery she had a history of prolonged bleeding, amenorrhea and inability to lactate. She had hypogonadotropic hypogonadism, hyperprolactinemia and growth hormone deficiency. Serum cortisol and adrenocorticotropic hormone levels were normal. Her magnetic resonance imaging was empty sella. Our diagnosis was GD co-existing with SS. GD with concomitant hypopituitarism is rare but has been described previously, but there are no reports of GD occurring with SS. In this case study, we report a patient with GD associated with SS.

  14. Genes and processed paralogs co-exist in plant mitochondria.

    Science.gov (United States)

    Cuenca, Argelia; Petersen, Gitte; Seberg, Ole; Jahren, Anne Hoppe

    2012-04-01

    RNA-mediated gene duplication has been proposed to create processed paralogs in the plant mitochondrial genome. A processed paralog may retain signatures left by the maturation process of its RNA precursor, such as intron removal and no need of RNA editing. Whereas it is well documented that an RNA intermediary is involved in the transfer of mitochondrial genes to the nucleus, no direct evidence exists for insertion of processed paralogs in the mitochondria (i.e., processed and un-processed genes have never been found simultaneously in the mitochondrial genome). In this study, we sequenced a region of the mitochondrial gene nad1, and identified a number of taxa were two different copies of the region co-occur in the mitochondria. The two nad1 paralogs differed in their (a) presence or absence of a group II intron, and (b) number of edited sites. Thus, this work provides the first evidence of co-existence of processed paralogs and their precursors within the plant mitochondrial genome. In addition, mapping the presence/absence of the paralogs provides indirect evidence of RNA-mediated gene duplication as an essential process shaping the mitochondrial genome in plants.

  15. The plausible role of carbonate in photo-catalytic water oxidation processes.

    Science.gov (United States)

    Kornweitz, Haya; Meyerstein, Dan

    2016-04-28

    DFT calculations point out that the photo-oxidation of water on GaN is energetically considerably facilitated by adsorbed carbonate. As the redox potential of the couple CO3(˙-)/CO3(2-) is considerably lower than that of the couple OH˙/OH(-) but still enables the oxidation of water it is suggested that carbonate should be considered as a catalyst/co-catalyst in a variety of catalytic/photo-catalytic/electro-catalytic oxidation processes.

  16. Catalytic upgrading of duckweed biocrude in subcritical water.

    Science.gov (United States)

    Zhang, Caicai; Duan, Peigao; Xu, Yuping; Wang, Bing; Wang, Feng; Zhang, Lei

    2014-08-01

    Herein, a duckweed biocrude produced from the hydrothermal liquefaction of Lemna minor was treated in subcritical water with added H₂. Effects of several different commercially available materials such as Ru/C, Pd/C, Pt/C, Pt/γ-Al₂O₃, Pt/C-sulfide, Rh/γ-Al₂O₃, activated carbon, MoS₂, Mo₂C, Co-Mo/γ-Al₂O₃, and zeolite on the yields of product fractions and the deoxygenation, denitrogenation, and desulfurization of biocrude at 350°C were examined, respectively. All the materials showed catalytic activity for deoxygenation and desulfurization of the biocrude and only Ru/C showed activity for denitrogenation. Of those catalysts examined, Pt/C showed the best performance for deoxygenation. Among all the upgraded oils, the oil produced with Ru/C shows the lowest sulfur, the highest hydrocarbon content (25.6%), the highest energy recovery (85.5%), and the highest higher heating value (42.6 MJ/kg). The gaseous products were mainly unreacted H₂, CH₄, CO₂, and C₂H6.

  17. Hydrogen production by catalytic gasification of cellulose in supercritical water

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Cellulose,one of the important components of biomass,was gasified in supercritical water to produce hydrogen-rich gas in an autoclave which was operated batch-wise under high-pressure.K2CO3 and Ca(OH)2 were selected as the catalysts (or promoters).The temperature was kept between 450℃ and 500℃ while pressure was maintained at 24-26 MPa.The reaction time was 20 min.Experimental results showed that the two catalysts had good catalytic effect and optimum amounts were observed for each catalyst.When 0.2 g K2CO3 was added,the hydrogen yield could reach 9.456 mol.kg-1 which was two times of the H2 amount produced without catalyst.When 1.6 g Ca(OH)2 was added,the H2 yield was K2CO3 as catalyst but is still 1.7 times that achieved without catalyst.Comparing with the results obtained using KaCO3 or Ca(OH)2 alone,the use of a combination of K2CO3 and Ca(OH)2 could increase the H2 yield by up to 2.5 times that without catalyst and 25% and 45% more than that obtained using K2CO3 and Ca(OH)2 alone,respectively.It was found that methane was the dominant product at relatively low temperature.When the temperature was increased,the methane reacts with water and is converted to hydrogen and carbon dioxide.

  18. Energy Conservation:Challenges and Opportunities Co-existing

    Institute of Scientific and Technical Information of China (English)

    Sun Yongjian

    2006-01-01

    @@ Yang Zhenhuai, Chairman, China Energy Conservation Association:China such has a large population,but natural resources as infields, water, oil and gas, etc.,are in comparative scarce. The zoology environment is comparatively weak. During the past 20 years, the economic growth has been realized mainly on through resource exploitation, heavy pollution and expansion, the environmental pollution and zoological destruction have developed to a very serious extent.

  19. Energy Conservation:Challenges and Opportunities Co-existing

    Institute of Scientific and Technical Information of China (English)

    Sun; Yongjian

    2006-01-01

      Yang Zhenhuai, Chairman, China Energy Conservation Association:China such has a large population,but natural resources as infields, water, oil and gas, etc.,are in comparative scarce. The zoology environment is comparatively weak. During the past 20 years, the economic growth has been realized mainly on through resource exploitation, heavy pollution and expansion, the environmental pollution and zoological destruction have developed to a very serious extent.……

  20. The effect of co-existing solutes on arsenate removal with hydrotalcite compound.

    Science.gov (United States)

    Kiso, Y; Jung, Y J; Yamamoto, H; Oguchi, T; Kuzawa, K; Yamada, T; Kim, S S; Ahn, K H

    2010-01-01

    Hydrotalcite (HTAL-Cl), an inorganic anion exchanger, is of use as an adsorbent for the removal of arsenate (As(V)) in water systems. The adsorption properties of HTAL-Cl for As(V) and the effects of co-existing anions on the As(V) removal performance were investigated in this work. Under the conditions of pH>or=4, the adsorption capacity for As(V) gradually decreased with an increase of pH, but As(V) was removed effectively within the range of pH = 5-8. Co-existing anions interfered As(V) removal, and the effect decreased in the order of HPO(4)(2-) > HCO(3)(-) > SO(4)(2-) > Cl(-). In binary solute systems containing phosphate and As(V), the maximum adsorption capacity of HTAL-Cl was 0.95 mmol g(-1) for phosphate and 0.65 mmol g(-1) for As(V): the total of these values corresponded to the maximum adsorption capacity for As(V) in single solute systems. The adsorption isotherms in these binary solute systems were approximated by the following modified Langmuir equations:As(V): q(As) = 18.7 radicalC(As)/(1 + 21.5 radicalC(P) + 12.8 radicalC(As)), phosphate : q(P) = 33.1 radicalC(P)/(1 + 21.5 radicalC(P) + 12.8 radicalC(As)). The column adsorption experiments showed that the adsorbed As(V) was released by the phosphate adsorption, because phosphate was adsorbed more strongly on HTAL-CL than As(V).

  1. Allee effects and species co-existence in an environment where resource abundance varies.

    Science.gov (United States)

    M'Gonigle, Leithen K; Greenspoon, Philip B

    2014-11-21

    Explaining patterns of diversity has long been a central focus in ecology. One of the most challenging problems has been to understand how species occupying similar ecological niches can co-exist because, with limited resources, demographic stochasticity is expected to lead to the eventual extinction of all but one of them. The Allee effect has been widely studied for its impact on the extinction risk of rare species. Its potential role in promoting co-existence has received less attention. Here, we present a model in which two species compete for a single resource across a continuous landscape. We show that Allee effects can promote their co-existence when a simple condition is met: resources are distributed unevenly across space. Furthermore, the Allee effect can stabilize co-existence despite the reduction in population density and consequent increase in demographic stochasticity that it causes. The Allee effect might, therefore, be an important force maintaining diverse communities.

  2. Osteomalacia and coxa vara. An unusual co-existence for femoral neck stress fracture

    Directory of Open Access Journals (Sweden)

    Kerim Sariyilmaz

    2015-01-01

    Conclusion: Joint and bone pain without any trauma should be investigated and bone metabolism disorders should be kept in mind. There might be co-existing factors related with stress fractures, and they must be treated simultaneously.

  3. [Catalytic ozonation of nitrobenzene in water by acidification-activated red mud].

    Science.gov (United States)

    Kang, Ya-ning; Li, Hua-nan; Xu, Bing-bing; Qi, Fei; Zhao, Lun

    2013-05-01

    Red mud as one kind of aluminum industrial wastes was used as raw material for catalyst preparation. It was activated by acidification in order to enhance its catalytic activity in the system of catalytic ozonation. Furthermore, removal performance and reaction mechanism in degradation of organic pollutants were discussed. Results showed that acid modified red mud had more significant catalytic activity than the raw red mud. The removal efficiency of nitrobenzene by catalytic ozonation with acidified red mud (RM6.0) increased with the increasing ozone concentration. When the ozone concentration was increased from 0.4 mg x L(-1) to 1.7 mg x L(-1), the removal efficiency of nitrobenzene increased from 45% to 92%. There was a consistent effect of water pH on the removal efficiency and the ozone concentration variation. The variation of the removal efficiency depended on the initial water pH. This was because the concentration of OH(-) led to ozone decomposition to generate hydroxyl radicals. The higher water pH value led to the quenching of hydroxyl radicals, resulting in the reduction of catalytic activity of RM6.0. The experimental results of aqueous ozone concentration variation in the presence of RM6.0 and inhibition by hydroxyl radicals indicated that the main reaction mechanism was catalytic ozonation of NB. Firstly, aqueous ozone was absorbed onto the surface of RM6.0, and then the concentrated ozone oxidized NB in water which was with a combination of direct and indirect oxidation. In catalytic reaction, hydroxyl radicals were present, which were generated during the oxidation of NB on the surface of RM6.0.

  4. Catalytical degradation of relevant pollutants from waters using magnetic nanocatalysts

    Science.gov (United States)

    Nadejde, C.; Neamtu, M.; Schneider, R. J.; Hodoroaba, V.-D.; Ababei, G.; Panne, U.

    2015-10-01

    The catalytic efficiency of two magnetically responsive nanocatalysts was evaluated for the degradation of Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84) azo dyes using hydrogen peroxide as oxidant under very mild conditions (atmospheric pressure, room temperature). In order to obtain the nanocatalysts, the surface of magnetite (Fe3O4) nanoparticles, prepared by a co-precipitation method, was further modified with ferrous oxalate, a highly sensitive non-hazardous reducing agent. The sensitized nanomaterials were characterized by X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry, and used in the catalytic wet hydrogen peroxide oxidation (CWHPO) of RB5 and RY84, in laboratory-scale experiments. The effect of important variables such as catalyst dosage, H2O2 concentration, and contact time was studied in the dye degradation kinetics. The results showed that it was possible to remove up to 99.7% dye in the presence of 20 mM H2O2 after 240 min of oxidation for a catalyst concentration of 10 g L-1 at 25 °C and initial pH value of 9.0. CWHPO of reactive dyes using sensitized magnetic nanocatalysts can be a suitable pre-treatment method for complete decolorization of effluents from textile dyeing and finishing processes, once the optimum operating conditions are established.

  5. The ISS Water Processor Catalytic Reactor as a Post Processor for Advanced Water Reclamation Systems

    Science.gov (United States)

    Nalette, Tim; Snowdon, Doug; Pickering, Karen D.; Callahan, Michael

    2007-01-01

    Advanced water processors being developed for NASA s Exploration Initiative rely on phase change technologies and/or biological processes as the primary means of water reclamation. As a result of the phase change, volatile compounds will also be transported into the distillate product stream. The catalytic reactor assembly used in the International Space Station (ISS) water processor assembly, referred to as Volatile Removal Assembly (VRA), has demonstrated high efficiency oxidation of many of these volatile contaminants, such as low molecular weight alcohols and acetic acid, and is considered a viable post treatment system for all advanced water processors. To support this investigation, two ersatz solutions were defined to be used for further evaluation of the VRA. The first solution was developed as part of an internal research and development project at Hamilton Sundstrand (HS) and is based primarily on ISS experience related to the development of the VRA. The second ersatz solution was defined by NASA in support of a study contract to Hamilton Sundstrand to evaluate the VRA as a potential post processor for the Cascade Distillation system being developed by Honeywell. This second ersatz solution contains several low molecular weight alcohols, organic acids, and several inorganic species. A range of residence times, oxygen concentrations and operating temperatures have been studied with both ersatz solutions to provide addition performance capability of the VRA catalyst.

  6. Catalytic water oxidation by mononuclear Ru complexes with an anionic ancillary ligand.

    Science.gov (United States)

    Tong, Lianpeng; Inge, A Ken; Duan, Lele; Wang, Lei; Zou, Xiaodong; Sun, Licheng

    2013-03-04

    Mononuclear Ru-based water oxidation catalysts containing anionic ancillary ligands have shown promising catalytic efficiency and intriguing properties. However, their insolubility in water restricts a detailed mechanism investigation. In order to overcome this disadvantage, complexes [Ru(II)(bpc)(bpy)OH2](+) (1(+), bpc = 2,2'-bipyridine-6-carboxylate, bpy = 2,2'-bipyridine) and [Ru(II)(bpc)(pic)3](+) (2(+), pic = 4-picoline) were prepared and fully characterized, which features an anionic tridentate ligand and has enough solubility for spectroscopic study in water. Using Ce(IV) as an electron acceptor, both complexes are able to catalyze O2-evolving reaction with an impressive rate constant. On the basis of the electrochemical and kinetic studies, a water nucleophilic attack pathway was proposed as the dominant catalytic cycle of the catalytic water oxidation by 1(+), within which several intermediates were detected by MS. Meanwhile, an auxiliary pathway that is related to the concentration of Ce(IV) was also revealed. The effect of anionic ligand regarding catalytic water oxidation was discussed explicitly in comparison with previously reported mononuclear Ru catalysts carrying neutral tridentate ligands, for example, 2,2':6',2″-terpyridine (tpy). When 2(+) was oxidized to the trivalent state, one of its picoline ligands dissociated from the Ru center. The rate constant of picoline dissociation was evaluated from time-resolved UV-vis spectra.

  7. The effects of colonization, extinction and competition on co-existence in metacommunities.

    Science.gov (United States)

    Hunt, Julia J F G; Bonsall, Michael B

    2009-07-01

    1. The co-existence of competitors in heterogeneous landscapes depends on the processes of colonization, extinction and spatial scale. In this study, we explore the metapopulation dynamics of competitive interactions. 2. Rather than simply evaluating the outcome of interspecific competition in the traditional manner, we focus on both the local population dynamic effects and the regional metapopulation processes affecting species co-existence. 3. We develop a theoretical model of regional co-existence to generate a set of predictions on the patterns of colonization necessary for co-existence and the regional processes that can lead to competitive exclusion. We empirically test these predictions using metacommunity microcosms of the interaction between two bruchid beetles (Callosobruchus chinensis, Callosobruchus maculatus). 4. Using well-replicated time series of the interaction between the bruchids and statistical methods of model fitting, we show how the qualitative and quantitative pattern of interspecific competition between the bruchid beetles is shaped by the structure of the metacommunity. 5. In unlimited dispersal metacommunities, the global exclusion of the inferior competitor is shown to be influenced more by the processes associated with extinction rather than low colonization ability. In restricted dispersal metacommunities, we show how the co-existence of competitors in a spatially heterogeneous habitat (patches connected through limited dispersal) is affected by Allee effects and life-history [colonization (dispersal) - competition] trade-offs.

  8. GM crop co-existence: a question of choice, not prejudice.

    Science.gov (United States)

    Pearsall, Daniel

    2013-01-01

    The rapid uptake of biotech crops around the world demonstrates not only strong producer and consumer demand for the technology and its products, but also that where regulatory regimes function effectively and markets are allowed to operate as normal, co-existence between genetically modified (GM) and non-GM supply chains is readily achievable. However, the polarized debate over GMOs within the European Union over the past 15 years has resulted in a highly politicized and progressively impractical approach to the issue of GM crop co-existence, which in itself has become a further barrier to the technology's development. This article argues that co-existence should not be treated as a pro- or anti-GM issue, and that the aim of co-existence measures should be to permit consumer choice and freedom to operate whatever the production method involved. It suggests that supply chain-based solutions to co-existence, rather than Government prescription, offer the most pragmatic and flexible response to the commercial realities of servicing differentiated market demands.

  9. Catalytic Conversion of Glucose into 5-Hydroxymethylfurfural by Hf(OTf4 Lewis Acid in Water

    Directory of Open Access Journals (Sweden)

    Junjie Li

    2015-12-01

    Full Text Available A series of Lewis acidic metal salts were used for glucose dehydration to 5-hydroymethylfurfural (HMF in water. Effect of valence state, ionic radii of Lewis acidic cation, and the type of anions on the catalytic performance have been studied systematically. The experimental results showed that the valence state played an important role in determining catalytic activity and selectivity. It was found that a higher glucose conversion rate and HMF selectivity could be obtained over high valent Lewis acid salts, where the ionic radii of these Lewis acidic metal salts are usually relatively small. Analysis on the effect of the anions of Lewis acid salts on the catalytic activity and the selectivity suggested that a higher glucose conversion and HMF selectivity could be readily obtained with Cl−. Furthermore, the recyclability of high valence state Lewis acid salt was also studied, however, inferior catalytic performance was observed. The deactivation mechanism was speculated to be the fact that high valence state Lewis acid salt was comparatively easier to undergo hydrolysis to yield complicated metal aqua ions with less catalytic activity. The Lewis acidic activity could be recovered by introducing a stoichiometric amount of hydrochloric acid (HCl to the catalytic before the reaction.

  10. Photocatalytic Water-Splitting Reaction from Catalytic and Kinetic Perspectives

    KAUST Repository

    Hisatomi, Takashi

    2014-10-16

    Abstract: Some particulate semiconductors loaded with nanoparticulate catalysts exhibit photocatalytic activity for the water-splitting reaction. The photocatalysis is distinct from the thermal catalysis because photocatalysis involves photophysical processes in particulate semiconductors. This review article presents a brief introduction to photocatalysis, followed by kinetic aspects of the photocatalytic water-splitting reaction.Graphical Abstract: [Figure not available: see fulltext.

  11. Co-existing institutional logics and agency among top-level public servants

    DEFF Research Database (Denmark)

    Bjerregaard, Toke

    2011-01-01

    to address parts of this void. This study examines the agency exerted by top-level public servants through their everyday strategy and policy work in face of co-existing logics of public administration. The findings illustrate how their action strategies span from more passive strategies of coping...... with coexisting logics of administration to more skilled agency of combining logics aimed at enhancing their opportunity and action space. The study suggests that the interplay between co-existing institutional logics, action strategies and the practical skills of top-level public servants provides the basis...... for both coping and more proactive strategies in pluralistic public administrations. Findings illustrate the role of public servants' practical sense of realizable opportunities that inform such strategies of handling co-existing institutional logics. Implications for institutional studies of organizations...

  12. Catalytic membrane in denitrification of water: a means to facilitate intraporous diffusion of reactants

    NARCIS (Netherlands)

    Ilinich, O.M.; Cuperus, F.P.; Gemert, van R.W.; Gribov, E.N.; Nosova, L.V.

    2000-01-01

    The series of mono- and bi-metallic catalysts with Pd and/or Cu supported over γ-Al 2O 3 was investigated with respect to reduction of nitrate and nitrite ions in water by hydrogen. Pronounced limitations of catalytic performance due to intraporous diffusion of the reactants were observed in the rea

  13. Spacecraft Water Regeneration by Catalytic Wet Air Oxidation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this project is to develop advanced catalysts for a volatile removal assembly used to purify spacecraft water. The innovation of the proposed...

  14. Unification of catalytic water oxidation and oxygen reduction reactions: amorphous beat crystalline cobalt iron oxides.

    Science.gov (United States)

    Indra, Arindam; Menezes, Prashanth W; Sahraie, Nastaran Ranjbar; Bergmann, Arno; Das, Chittaranjan; Tallarida, Massimo; Schmeißer, Dieter; Strasser, Peter; Driess, Matthias

    2014-12-17

    Catalytic water splitting to hydrogen and oxygen is considered as one of the convenient routes for the sustainable energy conversion. Bifunctional catalysts for the electrocatalytic oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are pivotal for the energy conversion and storage, and alternatively, the photochemical water oxidation in biomimetic fashion is also considered as the most useful way to convert solar energy into chemical energy. Here we present a facile solvothermal route to control the synthesis of amorphous and crystalline cobalt iron oxides by controlling the crystallinity of the materials with changing solvent and reaction time and further utilize these materials as multifunctional catalysts for the unification of photochemical and electrochemical water oxidation as well as for the oxygen reduction reaction. Notably, the amorphous cobalt iron oxide produces superior catalytic activity over the crystalline one under photochemical and electrochemical water oxidation and oxygen reduction conditions.

  15. Conserved water-mediated H-bonding dynamics of catalytic Asn 175 in plant thiol protease

    Indian Academy of Sciences (India)

    Tapas K Nandi; Hridoy R Bairagya; Bishnu P Mukhopadhyay; K Sekar; Dipankar Sukul; Asim K Bera

    2009-03-01

    The role of invariant water molecules in the activity of plant cysteine protease is ubiquitous in nature. On analysing the 11 different Protein DataBank (PDB) structures of plant thiol proteases, the two invariant water molecules W1 and W2 (W220 and W222 in the template 1PPN structure) were observed to form H-bonds with the Ob atom of Asn 175. Extensive energy minimization and molecular dynamics simulation studies up to 2 ns on all the PDB and solvated structures clearly revealed the involvement of the H-bonding association of the two water molecules in fixing the orientation of the asparagine residue of the catalytic triad. From this study, it is suggested that H-bonding of the water molecule at the W1 invariant site better stabilizes the Asn residue at the active site of the catalytic triad.

  16. The development of catalytic nucleophilic additions of terminal alkynes in water.

    Science.gov (United States)

    Li, Chao-Jun

    2010-04-20

    One of the major research endeavors in synthetic chemistry over the past two decades is the exploration of synthetic methods that work under ambient atmosphere with benign solvents, that maximize atom utilization, and that directly transform natural resources, such as renewable biomass, from their native states into useful chemical products, thus avoiding the need for protecting groups. The nucleophilic addition of terminal alkynes to various unsaturated electrophiles is a classical (textbook) reaction in organic chemistry, allowing the formation of a C-C bond while simultaneously introducing the alkyne functionality. A prerequisite of this classical reaction is the stoichiometric generation of highly reactive metal acetylides. Over the past decade, our laboratory and others have been exploring an alternative, the catalytic and direct nucleophilic addition of terminal alkynes to unsaturated electrophiles in water. We found that various terminal alkynes can react efficiently with a wide range of such electrophiles in water (or organic solvent) in the presence of simple and readily available catalysts, such as copper, silver, gold, iron, palladium, and others. In this Account, we describe the development of these synthetic methods, focusing primarily on results from our laboratory. Our studies include the following: (i) catalytic reaction of terminal alkynes with acid chloride, (ii) catalytic addition of terminal alkynes to aldehydes and ketones, (iii) catalytic addition of alkynes to C=N bonds, and (iv) catalytic conjugate additions. Most importantly, these reactions can tolerate various functional groups and, in many cases, perform better in water than in organic solvents, clearly defying classical reactivities predicated on the relative acidities of water, alcohols, and terminal alkynes. We further discuss multicomponent and enantioselective reactions that were developed. These methods provide an alternative to the traditional requirement of separate steps in

  17. A polarized liquid-liquid interface meets visible light-driven catalytic water oxidation.

    Science.gov (United States)

    Rastgar, Shokoufeh; Pilarski, Martin; Wittstock, Gunther

    2016-09-15

    Hyperbranched nanostructured bismuth vanadate at a chemically polarized water/organic interface is applied for efficient visible light-driven catalytic oxidation of water in the presence of [Co(bpy)3](PF6)3 as an organic soluble electron acceptor. The photocurrent response originating from the transfer of photo-excited electrons in BiVO4 to [Co(bpy)3](3+) is measured by scanning electrochemical microscopy.

  18. Valorization of horse manure through catalytic supercritical water gasification.

    Science.gov (United States)

    Nanda, Sonil; Dalai, Ajay K; Gökalp, Iskender; Kozinski, Janusz A

    2016-06-01

    The organic wastes such as lignocellulosic biomass, municipal solid waste, sewage sludge and livestock manure have attracted attention as alternative sources of energy. Cattle manure, a waste generated in surplus amounts from the feedlot, has always been a chief environmental concern. This study is focused on identifying the candidacy of horse manure as a next generation feedstock for biofuel production through supercritical water gasification. The horse manure was gasified in supercritical water to examine the effects of temperature (400-600°C), biomass-to-water ratio (1:5 and 1:10) and reaction time (15-45min) at a pressure range of 23-25MPa. The horse manure and resulting biochar were characterized through carbon-hydrogen-nitrogen-sulfur (CHNS), inductively coupled plasma-mass spectrometry (ICP-MS), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and scanning electron microscopy (SEM). The effects of alkali catalysts such as NaOH, Na2CO3 and K2CO3 at variable concentrations (1-2wt%) were investigated to maximize the hydrogen yields. Supercritical water gasification of horse manure with 2wt% Na2CO3 at 600°C and 1:10 biomass-to-water ratio for 45min revealed maximum hydrogen yields (5.31mmol/g), total gas yields (20.8mmol/g) with greater carbon conversion efficiency (43.1%) and enhanced lower heating value of gas products (2920kJ/Nm(3)). The manure-derived biochars generated at temperatures higher than 500°C also demonstrated higher thermal stability (weight loss 70wt%) suggesting their application in enhancing soil fertility and carbon sequestration. The results propose that supercritical water gasification could be a proficient remediation technology for horse manure to generate hydrogen-rich gas products.

  19. GMO neighbourhoods - will co-existence be a geographically realistic possibility?

    DEFF Research Database (Denmark)

    Qvist, H. Witt; Lundsgaard, H.; Brandt, Jesper

    2006-01-01

    In Denmark, there has been widespread opposition to the use of Genetically Modified Organisms (GMO’s) as a result of which rules have been developed relating to the co-existence of GM, conventionally and organically produced crops. This has been in the form of a spatially elaborated implementation...

  20. Fungal communities in wheat grain show significant co-existence patterns among species

    DEFF Research Database (Denmark)

    Nicolaisen, M.; Justesen, A. F.; Knorr, K.;

    2014-01-01

    identified as ‘core’ OTUs as they were found in all or almost all samples and accounted for almost 99 % of all sequences. The remaining OTUs were only sporadically found and only in small amounts. Cluster and factor analyses showed patterns of co-existence among the core species. Cluster analysis grouped...

  1. Water Soluble Iron aminoclay for Catalytic Reduction of Nitrophenol

    Directory of Open Access Journals (Sweden)

    S. ANBU ANJUGAM VANDARKUZHALI

    2013-06-01

    Full Text Available Water soluble iron decorated phyllosilicate is synthesized through one pot sol-gel synthesis by a wet chemical method using NaBH4 as reducing agent. The as-synthesized nanocomposite is characterized by powder-XRD and TGA techniques. The morphology of the composite is obtained using HRSEM and HRTEM. The prepared nanocomposite is an efficient catalyst for the reduction of nitrophenol.

  2. Mechanism of catalytic oxidation of water-lipid substrate

    Science.gov (United States)

    Kraynik, V. V.; Ushkalova, V. N.

    2010-05-01

    The processes of ethyl oleate water-emulsion oxidation in the presence of copper (II) complexes with α-alanine as a catalyst were investigated spectroscopically. UV spectra of the samples revealed the competitive nature of the formation and decomposition of hydroperoxides in the course of oxidation. Vis spectra of the aqueous phase revealed the constant presence of copper (II) complex with α-alanine and the formation of a similar complex with copper (I) in organic phase. The involvement of these complexes in the reactions of chain nucleation and decay of hydroperoxides is suggested.

  3. Heterogeneous catalytic ozonation of ciprofloxacin in water with carbon nanotube supported manganese oxides as catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Sui, Minghao, E-mail: suiminghao.sui@gmail.com [State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Xing, Sichu; Sheng, Li; Huang, Shuhang; Guo, Hongguang [State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Ciprofloxacin in water was degraded by heterogeneous catalytic ozonation. Black-Right-Pointing-Pointer MnOx were supported on MWCNTs to serve as catalyst for ozonation. Black-Right-Pointing-Pointer MnOx/MWCNT exhibited highly catalytic activity on ozonation of ciprofloxacin in water. Black-Right-Pointing-Pointer MnOx/MWCNT resulted in effective antibacterial activity inhibition on ciprofloxacin. Black-Right-Pointing-Pointer MnOx/MWCNT promoted the generation of hydroxyl radicals. - Abstract: Carbon nanotube-supported manganese oxides (MnOx/MWCNT) were used as catalysts to assist ozone in degrading ciprofloxacin in water. Manganese oxides were successfully loaded on multi-walled carbon nanotube surfaces by simply impregnating the carbon nanotube with permanganate solution. The catalytic activities of MnOx/MWCNT in ciprofloxacin ozonation, including degradation, mineralization effectiveness, and antibacterial activity change, were investigated. The presence of MnOx/MWCNT significantly elevated the degradation and mineralization efficiency of ozone on ciprofloxacin. The microbiological assay with a reference Escherichia coli strain indicated that ozonation with MnOx/MWCNT results in more effective antibacterial activity inhibition of ciprofloxacin than that in ozonation alone. The effects of catalyst dose, initial ciprofloxacin concentration, and initial pH conditions on ciprofloxacin ozonation with MnOx/MWCNT were surveyed. Electron spin resonance trapping was applied to assess the role of MnOx/MWCNT in generating hydroxyl radicals (HO{center_dot}) during ozonation. Stronger 5,5-dimethyl-1-pyrroline-N-oxide-OH signals were observed in the ozonation with MnOx/MWCNT compared with those in ozonation alone, indicating that MnOx/MWCNT promoted the generation of hydroxyl radicals. The degradation of ciprofloxacin was studied in drinking water and wastewater process samples to gauge the potential effects of water background matrix on

  4. Removal of dissolved oxygen from water using a Pd-resin based catalytic reactor

    Institute of Scientific and Technical Information of China (English)

    Wenxin SHI; Chongwei CUI; Liye ZHAO; Shuili YU; Xia YUN

    2009-01-01

    The removal of dissolved oxygen (DO) from water was studied experimentally in a Pd-resin base catalyst reactor using purified hydrogen gas as a reducing agent. The effects of various operating conditions, such as hydrogen and water flow rates, height of the catalytic resin bed, temperature, pH value and nan time, on the removal of DO, had been studied extensively. The results shows that DO could be removed by the reactor from ppm to ppb levels at ambient temperature. Increases of temperature, H2gas rate and the height of the catalytic resin were helpful to improve the DO removal rate. The change of pH value fom 4 to 12 resulted in no effect on DO removal. Reaction time was the key factor to control the DO removal efficiency. Only when the reaction time was longer than 2.3 minutes under the experimental conditions, could a very low DO level be achieved.

  5. Catalytic Degradation of Water Fluorene%Guangzhou Chemical Industry

    Institute of Scientific and Technical Information of China (English)

    向林; 黄文章; 李林; 邓磊; 朱力敏; 沈丽

    2016-01-01

    Polycyclic aromatic hydrocarbons ( PAHs ) as persistent organic pollutants ( POPs ) are carcinogenic, terato-genic, mutagenic. It is widely present in the atmosphere, water, soil and plants and animals. Selected polycyclicaromatic hydrocarbons fluorene as a research object, nano Fe-Ni bimetallic amount of orthogonal experiment, the initial concentration, pH value and temperature were optimzed to find the best conditions for the removal of fluorene. The results showed that under the conditions of the bimetallic dosage of 3 g/L, fluorene initial concentration of 0. 5 mg/L, temperature of 30 ℃, pH value of 5, the best removal was received, removal rate was 96. 2%.%多环芳烃( PAHs)是一类难降解性,致癌、致畸、致突变且易在生物体内富集的持久性有机污染物( POPs),它广泛存在于大气、水、动植物和土壤中。本研究选取多环芳烃中芴作为研究对象,通过正交实验优化纳米Fe-Ni双金属添加量、初始浓度、 pH值及温度,寻找芴的最佳去除条件。实验结果表明:当纳米Fe-Ni双金属添加量为3 g/L、芴初始浓度为0.5 mg/L、温度为30℃、 pH为5的条件下,去除效果最好,去除率可达到96.2%。

  6. Co-existence of various clinical and histopathological features of mycosis fungoides in a young female.

    Science.gov (United States)

    Naeini, Farahnaz Fatemi; Soghrati, Mehrnaz; Abtahi-Naeini, Bahareh; Najafian, Jamshid; Rajabi, Parvin

    2015-01-01

    Mycosis fungoides is the most common type of cutaneous T-cell lymphoma (CTCL) and a rare disorder that typically affects older adults with erythematous scaling patches and plaques. Hypopigmented patches are a rare clinical variant of the disease. Granulomatous mycosis fungoides (GMF) is also a rare type of CTCL. No particular clinical criteria are available for the diagnosis of GMF, because of its variable presentations, and so the detection of GMF is primarily considered as a histopathological diagnosis. Rarely, a co-existence of more than one clinical or histopathological feature of mycosis fungoides may be present. To the best of our knowledge this is the first report of MF that shows the simultaneous co-existence of more than one clinical and histopathological variant of MF. We present a 29-year-old female with clinical presentations of both classic and hypopigmented mycosis fungoides (MF), and also the histopathological features of the classic and granulomatous types of the disease.

  7. Sinobronchial allergic aspergillosis with allergic bronchopulmonary aspergillosis: a less common co-existence.

    Science.gov (United States)

    Upadhyay, Rashmi; Kant, Surya; Prakash, Ved; Saheer, S

    2014-11-04

    Allergic bronchopulmonary aspergillosis (ABPA) is an immunological pulmonary disorder that is characterised by a hyper-responsiveness of the airways to Aspergillus fumigatus. Although several other fungi may also present with similar clinical conditions, Aspergillus remains the most common fungal pathogen causing airway infections. Co-existence of ABPA with allergic Aspergillus sinusitis (AAS) is an uncommon presentation. The concept of one airway/one disease justifies the co-existence of ABPA with AAS, but it does not always hold true. We report a case of a 35-year-old woman who presented with symptoms suggestive of bronchial asthma. On further investigation, the radiological pattern showed fleeting shadows and CT scan showed central cystic bronchiectatic changes characteristic of ABPA. The nasal secretions were investigated for the presence of Aspergillus and were found to be positive. Hence a diagnosis of ABPA with AAS was established. The patient was treated with oral steroids and antifungal drugs.

  8. Sinobronchial allergic aspergillosis with allergic bronchopulmonary aspergillosis: a less common co-existence

    Science.gov (United States)

    Upadhyay, Rashmi; Kant, Surya; Prakash, Ved; Saheer, S

    2014-01-01

    Allergic bronchopulmonary aspergillosis (ABPA) is an immunological pulmonary disorder that is characterised by a hyper-responsiveness of the airways to Aspergillus fumigatus. Although several other fungi may also present with similar clinical conditions, Aspergillus remains the most common fungal pathogen causing airway infections. Co-existence of ABPA with allergic Aspergillus sinusitis (AAS) is an uncommon presentation. The concept of one airway/one disease justifies the co-existence of ABPA with AAS, but it does not always hold true. We report a case of a 35-year-old woman who presented with symptoms suggestive of bronchial asthma. On further investigation, the radiological pattern showed fleeting shadows and CT scan showed central cystic bronchiectatic changes characteristic of ABPA. The nasal secretions were investigated for the presence of Aspergillus and were found to be positive. Hence a diagnosis of ABPA with AAS was established. The patient was treated with oral steroids and antifungal drugs. PMID:25371437

  9. Pancreatic insulinoma co-existing with gastric GIST in the absence of neurofibromatosis-1

    Directory of Open Access Journals (Sweden)

    O'Sullivan Brendan

    2009-02-01

    Full Text Available Abstract Background Gastrointestinal stromal tumours (GIST frequently occur in patients with neurofibromatosis type 1 (NF-1. It has been reported that GIST may co-exist with pancreatic endocrine tumors but this has only been in association with NF-1. Case presentation A 76 year old woman presented with a 12 month history of hypoglycaemia symptoms. Abdominal CT scan demonstrated a 13 mm insulinoma localized in the tail of her pancreas. She was commenced on diazoxide and later underwent surgery for enucleation of insulinoma when a small ( Conclusion This is the first case report of a pancreatic insulinoma co-existing with a GIST in a patient without NF-1. In addition, we make the first report of rapidly growing cystic GIST recurrence following resection of a primary GIST tumour.

  10. Co-existence of Gel and Fluid Lipid Domains in Single-component Phospholipid Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Clare L [McMaster University; Barrett, M [McMaster University; Toppozini, L [McMaster University; Yamani, Zahra [Canadian Neutron Beam Centre, National Research Council, Chalk River Laboratorie; Kucerka, Norbert [Canadian Neutron Beam Centre and Comelius University (Slovakia); Katsaras, John [ORNL; Fragneto, Giovanna [Institut Laue-Langevin (ILL); Rheinstadter, Maikel C [McMaster University

    2012-01-01

    Lateral nanostructures in membranes, so-called rafts, are believed to strongly influence membrane properties and functions. The experimental observation of rafts has proven difficult as they are thought to be dynamic structures that likely fluctuate on nano- to microsecond time scales. Using neutron diffraction we present direct experimental evidence for the co-existence of gel and fluid lipid domains in a single-component phospholipid membrane made of DPPC as it undergoes its main phase transition. The coherence length of the neutron beam sets a lower limit for the size of structures that can be observed. Neutron coherence lengths between 30 and 242A used in this study were obtained by varying the incident neutron energy and the resolution of the neutron spectrometer. We observe Bragg peaks corresponding to co-existing nanometer sized structures, both in out-of-plane and in-plane scans, by tuning the neutron coherence length. During the main phase transition, instead of a continuous transition that shows a pseudo-critical behavior, we observe the co-existence of gel and fluid domains.

  11. A graded catalytic-protective layer for an efficient and stable water-splitting photocathode

    Science.gov (United States)

    Gu, Jing; Aguiar, Jeffery A.; Ferrere, Suzanne; Steirer, K. Xerxes; Yan, Yong; Xiao, Chuanxiao; Young, James L.; Al-Jassim, Mowafak; Neale, Nathan R.; Turner, John A.

    2017-01-01

    Achieving solar-to-hydrogen efficiencies above 15% is key for the commercial success of photoelectrochemical water-splitting devices. While tandem cells can reach those efficiencies, increasing the catalytic activity and long-term stability remains a significant challenge. Here we show that annealing a bilayer of amorphous titanium dioxide (TiOx) and molybdenum sulfide (MoSx) deposited onto GaInP2 results in a photocathode with high catalytic activity (current density of 11 mA cm‑2 at 0 V versus the reversible hydrogen electrode under 1 sun illumination) and stability (retention of 80% of initial photocurrent density over a 20 h durability test) for the hydrogen evolution reaction. Microscopy and spectroscopy reveal that annealing results in a graded MoSx/MoOx/TiO2 layer that retains much of the high catalytic activity of amorphous MoSx but with stability similar to crystalline MoS2. Our findings demonstrate the potential of utilizing a hybridized, heterogeneous surface layer as a cost-effective catalytic and protective interface for solar hydrogen production.

  12. Photo catalytic degradation of methyl tert-Butyl Ether (MTBE) from contaminated water: complete mineralization

    Energy Technology Data Exchange (ETDEWEB)

    Eslami, A.; Nasseri, S.; Maleki, A.; Aghvami, T.

    2009-07-01

    Methyl tert-butyl ether (MTBE) has been commercially used as an octane enhancer to replace tetraethyl lead in gasoline since 1979. The high mobility, water solubility, and resistance to natural attenuation associated with MTBE may result in contamination of ground and surface waters. In this investigation the degradation of aqueous MTBE at relatively high concentrations was studied by UV-vis/TiO{sub 2}/O{sub 2} photo catalytic process. The effect of important operational parameters such as ph, oxygen flow, catalyst loading, and irradiation time were also studied. (Author)

  13. Use of formic acid as reducing agent for application in catalytic reduction of nitrate in water.

    Science.gov (United States)

    Garron, Anthony; Epron, Florence

    2005-08-01

    The reduction of nitrate in nitrogen using bimetallic palladium tin catalysts and hydrogen is an interesting process for water treatment. The aim of the present study is to use formic acid (FA) as a reducing agent and a pH buffer in order to substitute the mixture of hydrogen and carbon dioxide. The catalytic performances of a palladium tin catalyst supported on silica were evaluated in the presence of FA, as a function of the initial acid concentration and of the gas phase (N(2), CO(2), or H(2)). Results were compared to those obtained with hydrogen in the presence of carbon dioxide. Similar mechanisms seem to explain the identical catalytic performances observed with these two reducing agents.

  14. Catalytic degradation of the nerve agent VX by water-swelled polystyrene-supported ammonium fluorides.

    Science.gov (United States)

    Marciano, Daniele; Goldvaser, Michael; Columbus, Ishay; Zafrani, Yossi

    2011-10-21

    The catalytic degradation of the nerve agent VX (O-ethyl S-2-(diisopropylamino)ethyl methylphosphonothioate) by water-swelled polymer-supported ammonium fluorides is described. VX (0.06-0.53 mol/mol F(-)) is rapidly degraded (t(1/2) ∼ 10-30 min) to form the "G-analogue" (O-ethyl methylphosphonofluoridate), which hydrolyzes (t(1/2) ∼ 1-1.5 h) to the nontoxic EMPA (ethyl methylphosphonic acid). The toxic desethyl-VX is not formed. The catalytic effect of fluoride is maintained even when 6 equiv of VX are loaded. GB (O-isopropyl methylphosphonofluoridate) and desethyl-VX agents are also degraded under these conditions.

  15. Synergetic Effects of Alcohol/Water Mixing on the Catalytic Reductive Fractionation of Poplar Wood

    Energy Technology Data Exchange (ETDEWEB)

    Renders, Tom; Van den Bosch, Sander; Vangeel, Thijs; Ennaert, Thijs; Koelewijn, Steven-Friso; Van den Bossche, Gil; Courtin, Christophe M.; Schutyser, Wouter; Sels, Bert F.

    2016-12-05

    One of the foremost challenges in lignocellulose conversion encompasses the integration of effective lignin valorization in current carbohydrate-oriented biorefinery schemes. Catalytic reductive fractionation (CRF) of lignocellulose offers a technology to simultaneously produce lignin-derived platform chemicals and a carbohydrate-enriched pulp via the combined action of lignin solvolysis and metal-catalyzed hydrogenolysis. Herein, the solvent (composition) plays a crucial role. In this contribution, we study the influence of alcohol/water mixtures by processing poplar sawdust in varying MeOH/water and EtOH/water blends. The results show particular effects that strongly depend on the applied water concentration. Low water concentrations enhance the removal of lignin from the biomass, while the majority of the carbohydrates are left untouched (scenario A). Contrarily, high water concentrations favor the solubilization of both hemicellulose and lignin, resulting in a more pure cellulosic residue (scenario B). For both scenarios, an evaluation was made to determine the most optimal solvent composition, based on two earlier introduced empirical efficiency descriptors (denoted LFDE and LFFE). According to these measures, 30 (A) and 70 vol % water (B) showed to be the optimal balance for both MeOH/water and EtOH/water mixtures. This successful implementation of alcohol/water mixtures allows operation under milder processing conditions in comparison to pure alcohol solvents, which is advantageous from an industrial point of view.

  16. The remarkable effect of oxygen on the N2 selectivity of water catalytic denitrification by hydrogen.

    Science.gov (United States)

    Constantinou, Costas L; Costa, Costas N; Efstathiou, Angelos M

    2007-02-01

    The selective catalytic reduction of nitrates (NO3-) in pure water toward N2 formation by the use of gaseous H2 and in the presence of O2 (air) at 1 atm total pressure and 25 degrees C has been investigated over Pd-Cu supported on various mixed metal oxides, x wt % MO(x(/gamma-Al2O3 (MO(x) = CeO2, SrO, Mn2O3, Cr2O3, Y2O3, and TiO2). It is demonstrated for the firsttime that a remarkable improvement in N2 reaction selectivity (by 80 percentage units) can be achieved when oxygen is present in the reducing feed gas stream. In particular, significantly lower reaction selectivities toward NH4+ and NO2- can be obtained, whereas the rate of NO3- conversion is not significantly affected. Moreover, it was shown thatthe same effect is obtained over the Pd-Cu-supported catalysts irrespective to the chemical composition of support and the initial concentration of nitrates in water used. The Pd-Cu clusters supported on 4.8 wt%TiO2/gamma-Al2O3 resulted in a solid with the best catalytic behavior compared with the rest of supports examined, both in the presence and in the absence of oxygen in the reducing feed gas stream. DRIFTS studies performed following catalytic reduction by H2 of NO3- in water revealed that the presence of TiO2 in the Pd-Cu/TiO2-Al2O3 system enhanced the reactivity of adsorbed bidentate nitrate species toward H2. Nitrosyl species adsorbed on the alumina and titania support surfaces are considered as active intermediate species of the selective catalytic reduction of NO3- by H2 in water. Pd-Cu/TiO2-Al2O3 appears to be the most selective catalyst ever reported in the literature for the reduction of nitrates present in pure water into N2 by a reducing gas mixture of H2/air.

  17. A study on the photo catalytic decomposition reactions of organics dissolved in water (II)

    Energy Technology Data Exchange (ETDEWEB)

    Sung, K.W.; Na, J. W.; Cho, Y. H.; Chung, H. H

    2000-01-01

    Experiments on aqueous TiO{sub 2} photo catalytic reaction of nitrogen containing organic compounds such as ethylamine, phenylhydrazine, pyridine, urea and EDTA were carried out. Based on the values calculated for the distribution of ionic species and atomic charge, the characteristics of their photo catalytic decomposition were estimated. It was shown that the decomposition characteristics was linearly proportional to nitrogen atomic charge value. On the other hand, the effects of aqueous pH, oxygen content and concentration on the TiO{sub 2} photo catalytic characteristics of EDTA, EDTA-Cu(II) and EDTA-Fe(III) were experimentally investigated. All EDTA systems were decomposed better in the pH range of 2.5-3.0 and with more dissolved oxygen. These results could be applied to construction of a process for removal of organic impurities dissolved in a source of system water, or for treatment of EDTA-containing liquid waste produced by a chemical cleaning in the domestic NPPs. (author)

  18. Spatiotemporal Co-existence of Female Thyroid and Breast Cancers in Hangzhou, China

    Science.gov (United States)

    Fei, Xufeng; Christakos, George; Lou, Zhaohan; Ren, Yanjun; Liu, Qingmin; Wu, Jiaping

    2016-06-01

    Thyroid and breast cancers (TC, BC) are common female malignant tumors worldwide. Studies suggest that TC patients have a higher BC risk, and vice versa. However, it has not been investigated quantitatively if there is an association between the space-time TC and BC incidence distributions at the population level. This work aims to answer this question. 5358 TC and 8784 BC (female) cases were diagnosed in Hangzhou (China, 2008–2012). Pearson and Spearman rank correlation coefficients of the TC and BC incidences were high, and their patterns were geographically similar. The spatiotemporal co-existence of TC and BC distributions was investigated using the integrative disease predictability (IDP) criterion: if TC-BC association is part of the disease mapping knowledge bases, it should yield improved space-time incidence predictions. Improved TC (BC) incidence predictions were generated when integrating both TC and BC data than when using only TC (BC) data. IDP consistently demonstrated the spatiotemporal co-existence of TC and BC distributions throughout Hangzhou (2008–2012), which means that when the population experiences high incidences of one kind of cancer attention should be paid to the other kind of cancer too. The strength of TC-BC association was measured by the IDP coefficients and incidence prediction accuracy.

  19. Depressive disorders co-existing with Addison–Biermer anemia – case report

    Directory of Open Access Journals (Sweden)

    Just MJ

    2015-04-01

    Full Text Available Mark Jean Just,1 Mariusz Kozakiewicz2 1Department of General and Endocronological Surgery, Piekary Medical Centre, Piekary Slaskie, 2Department of Food Chemistry Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, Torun, Poland Background: Anemia is a disease that can co-exist with depression, other mental disorders, or somatic diseases. Anemia can imitate symptoms of depression, while depression symptoms can mask concurring symptoms of anemia.Case presentation: I am presenting a case of a 48-year-old woman with Addison–Biermer anemia, with co-existing mood disorders. The clinical analysis of the presented patient’s history indicates diagnostic problems and a need for a detailed analysis of drug-related complications that occurred during previous treatment, eg, in the form of neuroleptic malignant syndrome.Conclusion: The presented case report contains valuable guidelines that can be of assistance in diagnostics and treatment of patients treated for mental disorders, who are also diagnosed with somatic diseases. Keywords: anemia, autoimmune diseases, depression, neuroleptic malignant syndrome

  20. Spatiotemporal Co-existence of Female Thyroid and Breast Cancers in Hangzhou, China.

    Science.gov (United States)

    Fei, Xufeng; Christakos, George; Lou, Zhaohan; Ren, Yanjun; Liu, Qingmin; Wu, Jiaping

    2016-06-24

    Thyroid and breast cancers (TC, BC) are common female malignant tumors worldwide. Studies suggest that TC patients have a higher BC risk, and vice versa. However, it has not been investigated quantitatively if there is an association between the space-time TC and BC incidence distributions at the population level. This work aims to answer this question. 5358 TC and 8784 BC (female) cases were diagnosed in Hangzhou (China, 2008-2012). Pearson and Spearman rank correlation coefficients of the TC and BC incidences were high, and their patterns were geographically similar. The spatiotemporal co-existence of TC and BC distributions was investigated using the integrative disease predictability (IDP) criterion: if TC-BC association is part of the disease mapping knowledge bases, it should yield improved space-time incidence predictions. Improved TC (BC) incidence predictions were generated when integrating both TC and BC data than when using only TC (BC) data. IDP consistently demonstrated the spatiotemporal co-existence of TC and BC distributions throughout Hangzhou (2008-2012), which means that when the population experiences high incidences of one kind of cancer attention should be paid to the other kind of cancer too. The strength of TC-BC association was measured by the IDP coefficients and incidence prediction accuracy.

  1. Respiratory Distress Secondary to Rhabdomyosarcoma of the Tongue and Co-existent Choanal Atresia.

    Science.gov (United States)

    Chatopadhayay, Rahul; Tiwari, Preeti; Gangopadhyay, A N; Pandey, Vaibhav

    2016-07-01

    Whilst rhabdomyosarcoma (RMS) is the third most common solid tumour in children, congenital RMS of the tongue is extremely rare and usually present as painless progressive mass since birth (Dagher and Helman in Oncologist 4:34-44, 1999; Childs and Goudy in Int J Pediatr Otorhinolaryngol 5:126-128, 2010). In neonates, presentation with respiratory distress is unexpected as neonates are preferential nasal breathers and restricted oral breathing due to tumour usually poses no problem. We herein report a case of rhabdomyosarcoma of the tongue with co-existent unilateral choanal atresia, presenting with respiratory distress. The baby developed upper respiratory tract infection following which developed severe respiratory distress. Airway symptoms were precipitated as there was combined obstruction of both the nostrils due to infection or adenoid enlargement and unilateral chonal atresia. Treatment of respiratory distress in the presence of RMS and bilateral nasal pathology must first prioritise the security of the airway, before taking a multi-factorial approach to the therapy of the lingual mass (Childs and Goudy in Int J Pediatr Otorhinolaryngol 5:126-128, 2010). This case illustrates the importance of vigilance with respect to co-existent nasal pathology, in order to avoid the occurrence of complete airway obstruction. We therefore feel that any diagnosis of lingual RMS should warrant a formal examination of both nasal cavities.

  2. Co-existence and interaction between myxomycetes and other organisms in shared niches

    Directory of Open Access Journals (Sweden)

    Irina O. Dudka

    2013-12-01

    Full Text Available The ecology of myxomycetes co-existing with the Latridiidae (Coleoptera, bryophytes and ascomycetous, basidiomycetous and anamorphic fungi were studied in Crimea and at different locations on the left bank of Ukraine. Results from the left bank indicate that the Latridiidae feed on myxomycetes. Colonies of the most common 13 myxomycete species (which included Stemonitis axifera (Bull. Macbr., S. fusca Roth, S. splendens Rost., Fuligo septica (L. Wigg. and Mucilago crustacea Wigg. were inhabited by 5 species of the Latridiidae. Myxomycete spores were present in guts of 19 of the 25 beetle specimens investigated. Beetles Latridius hirtus, Enicmus rugosus and E fungicola seem to be obligate myxomycete feeders, while Corticarina truncatella was clearly facultative. 13 species of myxomycetes were recorded on 9 species of moss and 3 species of liverwort developing on decaying wood or bark in the Crimean Nature Reserve. Relations between myxomycetes and bryophytes on woody substrata are spatial rather than trophic, and are possibly regulated by specific microclimatic conditions inside bryophyte thallomes. 69 species of myxomycetes were found co-existing with 36 species of ascomycetes, 21 species of basidiomycetes and 9 species of anamorphic fungi in the Crimean Nature Reserve. Associations formed by myxomycetes and fungi on different woody substrata are analyzed.

  3. Mechanisms Leading to Co-Existence of Gas Hydrate in Ocean Sediments [Part 2 of 2

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Steven; Juanes, Ruben

    2011-12-31

    In this project we have sought to explain the co-existence of gas and hydrate phases in sediments within the gas hydrate stability zone. We have focused on the gas/brine interface at the scale of individual grains in the sediment. The capillary forces associated with a gas/brine interface play a dominant role in many processes that occur in the pores of sediments and sedimentary rocks. The mechanical forces associated with the same interface can lead to fracture initiation and propagation in hydrate-bearing sediments. Thus the unifying theme of the research reported here is that pore scale phenomena are key to understanding large scale phenomena in hydrate-bearing sediments whenever a free gas phase is present. Our analysis of pore-scale phenomena in this project has delineated three regimes that govern processes in which the gas phase pressure is increasing: fracturing, capillary fingering and viscous fingering. These regimes are characterized by different morphology of the region invaded by the gas. On the other hand when the gas phase pressure is decreasing, the corresponding regimes are capillary fingering and compaction. In this project, we studied all these regimes except compaction. Many processes of interest in hydrate-bearing sediments can be better understood when placed in the context of the appropriate regime. For example, hydrate formation in sub-permafrost sediments falls in the capillary fingering regime, whereas gas invasion into ocean sediments is likely to fall into the fracturing regime. Our research provides insight into the mechanisms by which gas reservoirs are converted to hydrate as the base of the gas hydrate stability zone descends through the reservoir. If the reservoir was no longer being charged, then variation in grain size distribution within the reservoir explain hydrate saturation profiles such as that at Mt. Elbert, where sand-rich intervals containing little hydrate are interspersed between intervals containing large hydrate

  4. Mechanisms Leading to Co-Existence of Gas Hydrate in Ocean Sediments [Part 2 of 2

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Steven; Juanes, Ruben

    2011-12-31

    In this project we have sought to explain the co-existence of gas and hydrate phases in sediments within the gas hydrate stability zone. We have focused on the gas/brine interface at the scale of individual grains in the sediment. The capillary forces associated with a gas/brine interface play a dominant role in many processes that occur in the pores of sediments and sedimentary rocks. The mechanical forces associated with the same interface can lead to fracture initiation and propagation in hydrate-bearing sediments. Thus the unifying theme of the research reported here is that pore scale phenomena are key to understanding large scale phenomena in hydrate-bearing sediments whenever a free gas phase is present. Our analysis of pore-scale phenomena in this project has delineated three regimes that govern processes in which the gas phase pressure is increasing: fracturing, capillary fingering and viscous fingering. These regimes are characterized by different morphology of the region invaded by the gas. On the other hand when the gas phase pressure is decreasing, the corresponding regimes are capillary fingering and compaction. In this project, we studied all these regimes except compaction. Many processes of interest in hydrate-bearing sediments can be better understood when placed in the context of the appropriate regime. For example, hydrate formation in sub-permafrost sediments falls in the capillary fingering regime, whereas gas invasion into ocean sediments is likely to fall into the fracturing regime. Our research provides insight into the mechanisms by which gas reservoirs are converted to hydrate as the base of the gas hydrate stability zone descends through the reservoir. If the reservoir was no longer being charged, then variation in grain size distribution within the reservoir explain hydrate saturation profiles such as that at Mt. Elbert, where sand-rich intervals containing little hydrate are interspersed between intervals containing large hydrate

  5. Mechanisms Leading to Co-Existence of Gas Hydrate in Ocean Sediments [Part 1 of 2

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Steven; Juanes, Ruben

    2011-12-31

    In this project we have sought to explain the co-existence of gas and hydrate phases in sediments within the gas hydrate stability zone. We have focused on the gas/brine interface at the scale of individual grains in the sediment. The capillary forces associated with a gas/brine interface play a dominant role in many processes that occur in the pores of sediments and sedimentary rocks. The mechanical forces associated with the same interface can lead to fracture initiation and propagation in hydrate-bearing sediments. Thus the unifying theme of the research reported here is that pore scale phenomena are key to understanding large scale phenomena in hydrate-bearing sediments whenever a free gas phase is present. Our analysis of pore-scale phenomena in this project has delineated three regimes that govern processes in which the gas phase pressure is increasing: fracturing, capillary fingering and viscous fingering. These regimes are characterized by different morphology of the region invaded by the gas. On the other hand when the gas phase pressure is decreasing, the corresponding regimes are capillary fingering and compaction. In this project, we studied all these regimes except compaction. Many processes of interest in hydrate-bearing sediments can be better understood when placed in the context of the appropriate regime. For example, hydrate formation in sub-permafrost sediments falls in the capillary fingering regime, whereas gas invasion into ocean sediments is likely to fall into the fracturing regime. Our research provides insight into the mechanisms by which gas reservoirs are converted to hydrate as the base of the gas hydrate stability zone descends through the reservoir. If the reservoir was no longer being charged, then variation in grain size distribution within the reservoir explain hydrate saturation profiles such as that at Mt. Elbert, where sand-rich intervals containing little hydrate are interspersed between intervals containing large hydrate

  6. Electrochemical Synthesis of Mo2C Catalytical Coatings for the Water-Gas Shift Reaction

    Science.gov (United States)

    Kuznetsov, Sergey A.; Dubrovskiy, Anton R.; Rebrov, Evgeny V.; Schouten, Jaap C.

    2007-11-01

    The electroreduction of CO32- ions on a molybdenum cathode in a NaCl-KCl-Li2CO3 melt was studied by cyclic voltammetry. The electrochemical synthesis of Mo2C on molybdenum substrates has been performed at 1123 K for 7 h with a cathodic current density of 5 mA cm-2. If molybdenum carbide is present as a thin (ca. 500 nm) film on a molybdenum substrate (Mo2C/Mo), its catalytic activity in the water gas-shift reaction is enhanced by at least an order of magnitude compared to that of the bulk Mo2C phase.

  7. Catalytic Dechlorination of Chlorobenzene in Water by Pd/Fe System

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Chlorobenzene was dechlorinated by Pd/Fe bimetallic system in water through catalytic reduction. The dechlorination rate increases with increase of bulk loading of Pd due to the increase of both the surface loading of the Pd and the total surface area. For conditions with 0.005% Pd/Fe, 45% dechlorination efficiency was achieved within 5 h. The dechlorinated reaction is believed to take place on the bimetal surface in a pseudo-first-order reaction, with the rate constant being 0.0043 min-1.

  8. Critical review of Pd-based catalytic treatment of priority contaminants in water.

    Science.gov (United States)

    Chaplin, Brian P; Reinhard, Martin; Schneider, William F; Schüth, Christoph; Shapley, John R; Strathmann, Timothy J; Werth, Charles J

    2012-04-03

    Catalytic reduction of water contaminants using palladium (Pd)-based catalysts and hydrogen gas as a reductant has been extensively studied at the bench-scale, but due to technical challenges it has only been limitedly applied at the field-scale. To motivate research that can overcome these technical challenges, this review critically analyzes the published research in the area of Pd-based catalytic reduction of priority drinking water contaminants (i.e., halogenated organics, oxyanions, and nitrosamines), and identifies key research areas that should be addressed. Specifically, the review summarizes the state of knowledge related to (1) proposed reaction pathways for important classes of contaminants, (2) rates of contaminant reduction with different catalyst formulations, (3) long-term sustainability of catalyst activity with respect to natural water foulants and regeneration strategies, and (4) technology applications. Critical barriers hindering implementation of the technology are related to catalyst activity (for some contaminants), stability, fouling, and regeneration. New developments overcoming these limitations will be needed for more extensive field-scale application of this technology.

  9. Familiality of co-existing ADHD and tic disorders: evidence from a large sibling study

    Directory of Open Access Journals (Sweden)

    Veit Roessner

    2016-07-01

    Full Text Available AbstractBackground: The association of attention-deficit/hyperactivity disorder (ADHD and tic disorder (TD is frequent and clinically important. Very few and inconclusive attempts have been made to clarify if and how the combination of ADHD+TD runs in families. Aim: To determine the first time in a large-scale ADHD sample whether ADHD+TD increases the risk of ADHD+TD in siblings and, also the first time, if this is independent of their psychopathological vulnerability in general. Methods: The study is based on the International Multicenter ADHD Genetics (IMAGE study. The present sub-sample of 2815 individuals included ADHD-index patients with co-existing TD (ADHD+TD, n=262 and without TD (ADHD-TD, n=947 as well as their 1606 full siblings (n=358 of the ADHD+TD index patients and n=1248 of the ADHD-TD index patients. We assessed psychopathological symptoms in index patients and siblings by using the strength and difficulties questionnaire (SDQ and the parent and teacher Conners’ long version Rating Scales (CRS. For disorder classification the Parental Account of Childhood Symptoms (PACS-Interview was applied in n = 271 children. Odds ratio with the GENMOD procedure (PROCGENMOD was used to test if the risk for ADHD, TD and ADHD+TD in siblings was associated with the related index patients’ diagnoses. In order to get an estimate for specificity we compared the four groups for general psychopathological symptoms.Results: Co-existing ADHD+TD in index patients increased the risk of both comorbid ADHD+TD and TD in the siblings of these index patients. These effects did not extend to general psychopathology. Interpretation: Co-existence of ADHD+TD may segregate in families. The same holds true for TD (without ADHD. Hence, the segregation of TD (included in both groups seems to be the determining factor, independent of further behavioral problems. This close relationship between ADHD and TD supports the clinical approach to carefully assess ADHD in

  10. Familiality of Co-existing ADHD and Tic Disorders: Evidence from a Large Sibling Study

    Science.gov (United States)

    Roessner, Veit; Banaschewski, Tobias; Becker, Andreas; Buse, Judith; Wanderer, Sina; Buitelaar, Jan K.; Sergeant, Joseph A.; Sonuga-Barke, Edmund J.; Gill, Michael; Manor, Iris; Miranda, Ana; Mulas, Fernando; Oades, Robert D.; Roeyers, Herbert; Steinhausen, Hans-Christoph; Faraone, Steven V.; Asherson, Philip; Rothenberger, Aribert

    2016-01-01

    Background: The association of attention-deficit/hyperactivity disorder (ADHD) and tic disorder (TD) is frequent and clinically important. Very few and inconclusive attempts have been made to clarify if and how the combination of ADHD+TD runs in families. Aim: To determine the first time in a large-scale ADHD sample whether ADHD+TD increases the risk of ADHD+TD in siblings and, also the first time, if this is independent of their psychopathological vulnerability in general. Methods: The study is based on the International Multicenter ADHD Genetics (IMAGE) study. The present sub-sample of 2815 individuals included ADHD-index patients with co-existing TD (ADHD+TD, n = 262) and without TD (ADHD–TD, n = 947) as well as their 1606 full siblings (n = 358 of the ADHD+TD index patients and n = 1248 of the ADHD-TD index patients). We assessed psychopathological symptoms in index patients and siblings by using the Strength and Difficulties Questionnaire (SDQ) and the parent and teacher Conners' long version Rating Scales (CRS). For disorder classification the Parental Account of Childhood Symptoms (PACS-Interview) was applied in n = 271 children. Odds ratio with the GENMOD procedure (PROCGENMOD) was used to test if the risk for ADHD, TD, and ADHD+TD in siblings was associated with the related index patients' diagnoses. In order to get an estimate for specificity we compared the four groups for general psychopathological symptoms. Results: Co-existing ADHD+TD in index patients increased the risk of both comorbid ADHD+TD and TD in the siblings of these index patients. These effects did not extend to general psychopathology. Interpretation: Co-existence of ADHD+TD may segregate in families. The same holds true for TD (without ADHD). Hence, the segregation of TD (included in both groups) seems to be the determining factor, independent of further behavioral problems. This close relationship between ADHD and TD supports the clinical approach to carefully assess ADHD in any case

  11. The effect of temperature on the catalytic conversion of Kraft lignin using near-critical water

    DEFF Research Database (Denmark)

    Nguyen, Thi Dieu Huyen; Maschietti, Marco; Åmand, Lars-Erik

    2014-01-01

    The catalytic conversion of suspended LignoBoost Kraft lignin was performed in near-critical water using ZrO2/K2CO3 as the catalytic system and phenol as the co-solvent and char suppressing agent. The reaction temperature was varied from 290 to 370 C and its effect on the process was investigated...... in a continuous flow (1 kg/h). The yields of water-soluble organics (WSO), bio-oil and char (dry lignin basis) were in the ranges of 5–11%, 69–87% and 16–22%, respectively. The bio-oil, being partially deoxygenated, exhibited higher carbon content and heat value, but lower sulphur content than lignin. The main 1......-ring aromatics (in WSO and diethylether-soluble bio-oil) were anisoles, alkylphenols, catechols and guaiacols. The results show that increasing temperature increases the yield of 1-ring aromatics remarkably, while it increases the formation of char moderately. An increase in the yields of anisoles...

  12. Synthesis of Water Dispersible and Catalytically Active Gold-Decorated Cobalt Ferrite Nanoparticles.

    Science.gov (United States)

    Silvestri, Alessandro; Mondini, Sara; Marelli, Marcello; Pifferi, Valentina; Falciola, Luigi; Ponti, Alessandro; Ferretti, Anna Maria; Polito, Laura

    2016-07-19

    Hetero-nanoparticles represent an important family of composite nanomaterials that in the past years are attracting ever-growing interest. Here, we report a new strategy for the synthesis of water dispersible cobalt ferrite nanoparticles (CoxFe3-xO4 NPs) decorated with ultrasmall (2-3 nm) gold nanoparticles (Au NPs). The synthetic procedure is based on the use of 2,3-meso-dimercaptosuccinic acid (DMSA), which plays a double role. First, it transfers cobalt ferrite NPs from the organic phase to aqueous media. Second, the DMSA reductive power promotes the in situ nucleation of gold NPs in proximity of the magnetic NP surface. Following this procedure, we achieved a water dispersible nanosystem (CoxFe3-xO4-DMSA-Au NPs) which combines the cobalt ferrite magnetic properties with the catalytic features of ultrasmall Au NPs. We showed that CoxFe3-xO4-DMSA-Au NPs act as an efficient nanocatalyst to reduce 4-nitrophenol to 4-aminophenol and that they can be magnetically recovered and recycled. It is noteworthy that such nanosystem is more catalytically active than Au NPs with equal size. Finally, a complete structural and chemical characterization of the hetero-NPs is provided.

  13. Environmental Topology and Water Availability Modulates the Catalytic Activity of β-Galactosidase Entrapped in a Nanosporous Silicate Matrix.

    Science.gov (United States)

    Burgos, M Ines; Velasco, Manuel I; Acosta, Rodolfo H; Perillo, María A

    2016-11-04

    In the present work we studied the catalytic activity of E. coli β-Gal confined in a nanoporous silicate matrix (Eβ-Gal) at different times after the beginning of the sol-gel polymerization process. Enzyme kinetic experiments with two substrates (ONPG and PNPG) that differed in the rate-limiting steps of the reaction mechanism for their β-Gal-catalyzed hydrolysis, measurements of transverse relaxation times (T2) of water protons through (1)H-NMR, and scanning electron microscopy analysis of the gel nanostructure, were performed. In conjunction, results provided evidence that water availability is crucial for the modulation observed in the catalytic activity of β-Gal as long as water participate in the rate limiting step of the reaction (only with ONPG). In this case, a biphasic rate vs. substrate concentration was obtained exhibiting one phase with catalytic rate constant (kcA), similar to that observed in solution, and another phase with a higher and aging-dependent catalytic rate constant (kcB). More structured water populations (lower T2) correlates with higher catalytic rate constants (kcB). The T2-kcB negative correlation observed along the aging of gels within the 15-days period assayed reinforces the coupling between water structure and the hydrolysis catalysis inside gels.

  14. Co-existence of cutaneous leishmaniasis with pleural effusion: a case report from Iran.

    Directory of Open Access Journals (Sweden)

    Hossein Mortazavi

    2014-03-01

    Full Text Available Herein, a 12-year-old Afghan boy with chronic cutaneous leishmaniasis on the face and verrucous lesions on the body and pleural effusion suspected of having co-existent tuberculosis has been presented. The cutaneous lesions were appeared for five years before his admission. Leishman-Donovan bodies were seen in H&E (Hematoxylin and eosin slide of skin lesion specimens. The pathogenic species was proved to be Leishmania tropica using Polymerase Chain Reaction (PCR method. Purified Protein Derivative (PPD and Leishmanin Skin Test (LST were strongly positive. The patient was treated with systemic and intralesional meglumine antimoniate (Glucantime for cutaneous leishmaniasis and then with anti-tuberculosis drugs for pleural effusion. Afterwards, pleural effusion was disappeared and cutaneous leishmaniasis cured.

  15. A rare case of breast carcinoma co-existing with axillary mantle cell lymphoma

    Directory of Open Access Journals (Sweden)

    Scally John

    2003-12-01

    Full Text Available Abstract Background Mantle cell lymphoma (MCL is a rare variety of non-Hodgkin's lymphoma which originates from CD5+ B-cell population in the mantle zones of lymphoid follicles. Coexistence of such tumours in the axillary lymph nodes with invasive breast cancers without prior history of adjuvant chemotherapy or radiotherapy has not been previously reported in literature. Case report We report a rare case of breast cancer co-existing with stage I mantle cell lymphoma of the ipsilateral axillary lymph node detected fortuitously by population screening. Conclusion Though some studies have tried to prove breast carcinomas and lymphomas to share a common molecular or viral link, more research needs to be done to establish whether such a link truly exists.

  16. Catalytic electron-transfer oxygenation of substrates with water as an oxygen source using manganese porphyrins.

    Science.gov (United States)

    Fukuzumi, Shunichi; Mizuno, Takuya; Ojiri, Tetsuya

    2012-12-03

    Manganese(V)-oxo-porphyrins are produced by the electron-transfer oxidation of manganese-porphyrins with tris(2,2'-bipyridine)ruthenium(III) ([Ru(bpy)(3)](3+); 2 equiv) in acetonitrile (CH(3)CN) containing water. The rate constants of the electron-transfer oxidation of manganese-porphyrins have been determined and evaluated in light of the Marcus theory of electron transfer. Addition of [Ru(bpy)(3)](3+) to a solution of olefins (styrene and cyclohexene) in CH(3)CN containing water in the presence of a catalytic amount of manganese-porphyrins afforded epoxides, diols, and aldehydes efficiently. Epoxides were converted to the corresponding diols by hydrolysis, and were further oxidized to the corresponding aldehydes. The turnover numbers vary significantly depending on the type of manganese-porphyrin used owing to the difference in their oxidation potentials and the steric bulkiness of the ligand. Ethylbenzene was also oxidized to 1-phenylethanol using manganese-porphyrins as electron-transfer catalysts. The oxygen source in the substrate oxygenation was confirmed to be water by using (18)O-labeled water. The rate constant of the reaction of the manganese(V)-oxo species with cyclohexene was determined directly under single-turnover conditions by monitoring the increase in absorbance attributable to the manganese(III) species produced in the reaction with cyclohexene. It has been shown that the rate-determining step in the catalytic electron-transfer oxygenation of cyclohexene is electron transfer from [Ru(bpy)(3)](3+) to the manganese-porphyrins.

  17. Green Synthesis and Catalytic Activity of Gold Nanoparticles Synthesized by Artemisia capillaris Water Extract

    Science.gov (United States)

    Lim, Soo Hyeon; Ahn, Eun-Young; Park, Youmie

    2016-10-01

    Gold nanoparticles were synthesized using a water extract of Artemisia capillaris (AC-AuNPs) under different extract concentrations, and their catalytic activity was evaluated in a 4-nitrophenol reduction reaction in the presence of sodium borohydride. The AC-AuNPs showed violet or wine colors with characteristic surface plasmon resonance bands at 534 543 nm that were dependent on the extract concentration. Spherical nanoparticles with an average size of 16.88 ± 5.47 29.93 ± 9.80 nm were observed by transmission electron microscopy. A blue shift in the maximum surface plasmon resonance was observed with increasing extract concentration. The face-centered cubic structure of AC-AuNPs was confirmed by high-resolution X-ray diffraction analysis. Based on phytochemical screening and Fourier transform infrared spectra, flavonoids, phenolic compounds, and amino acids present in the extract contributed to the reduction of Au ions to AC-AuNPs. The average size of the AC-AuNPs decreased as the extract concentration during the synthesis was increased. Higher 4-nitrophenol reduction reaction rate constants were observed for smaller sizes. The extract in the AC-AuNPs was removed by centrifugation to investigate the effect of the extract in the reduction reaction. Interestingly, the removal of extracts greatly enhanced their catalytic activity by up to 50.4 %. The proposed experimental method, which uses simple centrifugation, can be applied to other metallic nanoparticles that are green synthesized with plant extracts to enhance their catalytic activity.

  18. First-principles quantum-mechanical investigations: The role of water in catalytic conversion of furfural on Pd(111)

    Science.gov (United States)

    Xue, Wenhua; Borja, Miguel Gonzalez; Resasco, Daniel E.; Wang, Sanwu

    2015-03-01

    In the study of catalytic reactions of biomass, furfural conversion over metal catalysts with the presence of water has attracted wide attention. Recent experiments showed that the proportion of alcohol product from catalytic reactions of furfural conversion with palladium in the presence of water is significantly increased, when compared with other solvent including dioxane, decalin, and ethanol. We investigated the microscopic mechanism of the reactions based on first-principles quantum-mechanical calculations. We particularly identified the important role of water and the liquid/solid interface in furfural conversion. Our results provide atomic-scale details for the catalytic reactions. Supported by DOE (DE-SC0004600). This research used the supercomputer resources at NERSC, of XSEDE, at TACC, and at the Tandy Supercomputing Center.

  19. A supramolecular ruthenium macrocycle with high catalytic activity for water oxidation that mechanistically mimics photosystem II

    Science.gov (United States)

    Schulze, Marcus; Kunz, Valentin; Frischmann, Peter D.; Würthner, Frank

    2016-06-01

    Mimicking the ingenuity of nature and exploiting the billions of years over which natural selection has developed numerous effective biochemical conversions is one of the most successful strategies in a chemist's toolbox. However, an inability to replicate the elegance and efficiency of the oxygen-evolving complex of photosystem II (OEC-PSII) in its oxidation of water into O2 is a significant bottleneck in the development of a closed-loop sustainable energy cycle. Here, we present an artificial metallosupramolecular macrocycle that gathers three Ru(bda) centres (bda = 2,2‧-bipyridine-6,6‧-dicarboxylic acid) that catalyses water oxidation. The macrocyclic architecture accelerates the rate of water oxidation via a water nucleophilic attack mechanism, similar to the mechanism exhibited by OEC-PSII, and reaches remarkable catalytic turnover frequencies >100 s-1. Photo-driven water oxidation yields outstanding activity, even in the nM concentration regime, with a turnover number of >1,255 and turnover frequency of >13.1 s-1.

  20. Sickness absence among female employees with migraine and co-existing conditions.

    Science.gov (United States)

    Mäki, K; Vahtera, J; Virtanen, M; Elovainio, M; Pentti, J; Keltikangas-Järvinen, L; Kivimäki, M

    2008-11-01

    This prospective cohort study examined the risk of sickness absence among 27,127 female public-sector employees by status of migraine and co-existing conditions. A baseline survey was used to assess chronic disorders and demographic factors. Information on sickness absence in the 3 years following the survey was obtained from employers' registers. Migraine was related to 5.4 extra sickness absence days per person-year, with the corresponding figures being 14.6 and 6.1 for depression and respiratory disorders, respectively. After adjusting for age, marital status, socioeconomic status and presence of depression or respiratory disorders, employees with migraine had a 1.21 (95% confidence interval 1.18, 1.24) times higher risk of self-certified sickness absence episodes ( 3 days) was 1.15 (1.12, 1.19). Among employees with depression or respiratory disorders, secondary migraine was associated with an increased risk of sickness absence episode of 1.15 to 1.23. These findings suggest that migraine is associated with increased risk of recorded sickness absence independent of depression and respiratory disorders.

  1. Cheating fosters species co-existence in well-mixed bacterial communities.

    Science.gov (United States)

    Leinweber, Anne; Fredrik Inglis, R; Kümmerli, Rolf

    2017-01-06

    Explaining the enormous biodiversity observed in bacterial communities is challenging because ecological theory predicts that competition between species occupying the same niche should lead to the exclusion of less competitive community members. Competitive exclusion should be particularly strong when species compete for a single limiting resource or live in unstructured habitats that offer no refuge for weaker competitors. Here, we describe the 'cheating effect', a form of intra-specific competition that can counterbalance between-species competition, thereby fostering biodiversity in unstructured habitats. Using experimental communities consisting of the strong competitor Pseudomonas aeruginosa (PA) and its weaker counterpart Burkholderia cenocepacia (BC), we show that co-existence is impossible when the two species compete for a single limiting resource, iron. However, when introducing a PA cheating mutant, which specifically exploits the iron-scavenging siderophores produced by the PA wild type, we found that biodiversity was preserved under well-mixed conditions where PA cheats could outcompete the PA wild type. Cheating fosters biodiversity in our system because it creates strong intra-specific competition, which equalizes fitness differences between PA and BC. Our study identifies cheating - typically considered a destructive element - as a constructive force in shaping biodiversity.The ISME Journal advance online publication, 6 January 2017; doi:10.1038/ismej.2016.195.

  2. The clinicopathologic differences in papillary thyroid carcinoma with or without co-existing chronic lymphocytic thyroiditis.

    Science.gov (United States)

    Yoon, Yeo-Hoon; Kim, Hak Joon; Lee, Jin Woo; Kim, Jin Man; Koo, Bon Seok

    2012-03-01

    The goal of this study is to determine the clinicopathologic differences in patients with papillary thyroid carcinoma (PTC) with or without chronic lymphocytic thyroiditis (CLT). We reviewed the medical records of 195 consecutive PTC patients who underwent total thyroidectomy and bilateral central lymph node dissection from April 2008 to March 2010. The differences in clinicopathologic factors, such as age, gender, size of primary tumor, perithyroidal invasion, lymphovascular invasion, capsular invasion, and central lymph node (CLN) metastasis, were analyzed in PTC patients with or without CLT. Among 195 patients, 56 (28.7%) had co-existing CLT. Patients with CLT had the following characteristics as compared to patients without CLT: significantly younger, female predominance, smaller tumor size, and lower incidence of capsular invasion (p = 0.038, 0.006, 0.037, and 0.026, respectively). Also, patients with CLT (12.5%) had a significantly lower incidence of CLN metastases than patients without CLT (28.1%; p = 0.025) based on univariate analysis. Moreover, multivariate analysis showed that younger age (p = 0.042, odds ratio = 1.033) and female gender (p = 0.012, odds ratio = 6.865) are independent clinical factors in patients with CLT compared to patients without CLT. CLT was shown to be commonly associated with PTC. Compared to patients with PTC without CLT, patients with CLT were younger with a female predominance, which are the most important and well-known prognostic variables for thyroid cancer mortality.

  3. Critical Issues in the Identification of Gifted Students With Co-Existing Disabilities

    Directory of Open Access Journals (Sweden)

    Barbara Jackson Gilman

    2013-09-01

    Full Text Available Federal law ensures all students with disabilities the right to a Free, Appropriate Public Education (FAPE. However, current policies governing a student’s eligibility for services may contribute to the underidentification of gifted children with co-existing disabilities—the Twice-Exceptional. The emphasis on below-grade-level (or lower performance, without regard to ability or potential weaknesses, misses twice-exceptional students. Those who perform at grade level, by using advanced conceptual abilities and hard work to compensate, may still require interventions and accommodations to manage increasing educational demands. Otherwise, college and even high school graduation may be out of reach. This article reviews changing laws and policies, explores case studies of twice-exceptional students missed, and examines the diagnosis of twice-exceptionality through comprehensive assessment. Appropriate best practices for the identification of twice-exceptional learners, maintenance of their civil rights, and provision of FAPE are offered for educators, parents, advocates, and legislators as federal, state, and district laws/policies evolve.

  4. Kinetic and Phase Behaviors of Catalytic Cracking Dry Gas Hydrate in Water-in-Oil Emulsion

    Institute of Scientific and Technical Information of China (English)

    MA Qinglan; HUANG Qiang; CHEN Guangjin; WANG Xiulin; SUN Changyu; YANG Lanying

    2013-01-01

    The systematic experimental studies were performed on the hydrate formation kinetics and gas-hydrate equilibrium for a simulated catalytic cracking gas in the water-in-oil emulsion.The effect of temperature,pressure and initial gas-liquid ratio on the hydrate formation was studied,respectively.The data were obtained at pressures ranging from 3.5 to 5 MPa and temperatures from 274.15 to 277.15 K.The results showed that hydrogen and methane can be separated from the C2+ fraction by forming hydrate at around 273.15 K which is much higher temperature than that of the cryogenic separation method,and the hydrate formation rate can be enhanced in the water-in-oil emulsion compared to pure water.The experiments provided the basic data for designing the industrial process,and setting the suitable operational conditions.The measured data of gas-hydrate equilibria were compared with the predictions by using the Chen-Guo hydrate thermodynamic model.

  5. Co-existence of multiple strains of porcine circovirus type 2 in the same pig from China.

    Science.gov (United States)

    Zhai, Shao-Lun; Chen, Sheng-Nan; Wei, Zu-Zhang; Zhang, Jian-Wu; Huang, Lv; Lin, Tao; Yue, Cheng; Ran, Duo-Liang; Yuan, Shi-Shan; Wei, Wen-Kang; Long, Jin-Xue

    2011-11-13

    Pigs are often co-infected by different viral strains from the same virus. Up to now, there are few reports about co-existence of different porcine circovirus type 2 (PCV2) strains in China. The aim of this study was to evaluate it in Chinese swine herds. 118 PCV2 positive DNAs isolated from diseased pigs identified by classic PCR were re-detected using a modified differential PCR assay. The results indicated that co-existence rates of PCV2 were 32.2% (38/118) in diseased pigs and 0% (0/41) in asymptomatic pigs. Four PCV2 complete genomes were cloned from two co-infected samples and their nucleotide (nt) identities were 95%-97.3%. The phylogenetic analysis showed that four PCV2 strains were divided into different genotypes, PCV2a, PCV2b, PCV2d and PCV2e, respectively. In addition, co-existence were not detected in 41 serum samples from healthy pigs but PCV2 single infection (31.7%, 13/41) existed. These data revealed that the co-existence of different strains of PCV2 might contribute to the development of more severe clinical symptoms for pigs. This is the first report confirming the co-existence of different PCV2 strains in Chinese swine herds. Meanwhile, this study could help us to understand new infection and prevalence forms of PCV2 clinically.

  6. Structural instability and phase co-existence driven non-Gaussian resistance fluctuations in metal nanowires at low temperatures.

    Science.gov (United States)

    Bid, Aveek; Raychaudhuri, A K

    2016-11-11

    We report a detailed experimental study of the resistance fluctuations measured at low temperatures in high quality metal nanowires ranging in diameter from 15-200 nm. The wires exhibit co-existing face-centered-cubic and 4H hcp phases of varying degrees as determined from the x-ray diffraction data. We observe the appearance of a large non-Gaussian noise for nanowires of diameter smaller than 50 nm over a certain temperature range around ≈30 K. The diameter range ∼30 nm, where the noise has maxima coincides with the maximum volume fraction of the co-existing 4H hcp phase thus establishing a strong link between the fluctuation and the phase co-existence. The resistance fluctuation in the same temperature range also shows a deviation of [Formula: see text] behavior at low frequency with appearance of single frequency Lorentzian type contribution in the spectral power density. The fluctuations are thermally activated with an activation energy [Formula: see text] meV, which is of same order as the activation energy of creation of stacking fault in FCC metals that leads to the co-existing crystallographic phases. Combining the results of crystallographic studies of the nanowires and analysis of the resistance fluctuations we could establish the correlation between the appearance of the large resistance noise and the onset of phase co-existence in these nanowires.

  7. Structural instability and phase co-existence driven non-Gaussian resistance fluctuations in metal nanowires at low temperatures

    Science.gov (United States)

    Bid, Aveek; Raychaudhuri, A. K.

    2016-11-01

    We report a detailed experimental study of the resistance fluctuations measured at low temperatures in high quality metal nanowires ranging in diameter from 15-200 nm. The wires exhibit co-existing face-centered-cubic and 4H hcp phases of varying degrees as determined from the x-ray diffraction data. We observe the appearance of a large non-Gaussian noise for nanowires of diameter smaller than 50 nm over a certain temperature range around ≈30 K. The diameter range ˜30 nm, where the noise has maxima coincides with the maximum volume fraction of the co-existing 4H hcp phase thus establishing a strong link between the fluctuation and the phase co-existence. The resistance fluctuation in the same temperature range also shows a deviation of 1/f behavior at low frequency with appearance of single frequency Lorentzian type contribution in the spectral power density. The fluctuations are thermally activated with an activation energy {E}{{a}}˜ 35 meV, which is of same order as the activation energy of creation of stacking fault in FCC metals that leads to the co-existing crystallographic phases. Combining the results of crystallographic studies of the nanowires and analysis of the resistance fluctuations we could establish the correlation between the appearance of the large resistance noise and the onset of phase co-existence in these nanowires.

  8. ChAT and NOS in human myenteric neurons: co-existence and co-absence.

    Science.gov (United States)

    Beck, Martin; Schlabrakowski, Anne; Schrödl, Falk; Neuhuber, Winfried; Brehmer, Axel

    2009-10-01

    Most myenteric neurons contain one of the two generating enzymes for major excitatory and inhibitory neurotransmitters: choline acetyltransferase (ChAT) or neuronal nitric oxide synthase (NOS). Two minor groups of myenteric neurons contain either both enzymes or neither. Our study had two aims: (1) to compare the proportions of neurons stained for ChAT and/or NOS in human small and large intestinal whole-mounts by co-staining with an antibody against the human neuronal protein Hu C/D (HU); (2) to characterize these neurons morphologically by co-staining with a neurofilament (NF) antibody. In small intestinal whole-mounts co-stained with HU, we counted more ChAT-positive (ChAT+) than NOS+ neurons (52% vs. 38%), whereas the large intestine exhibited fewer ChAT+ than NOS+ neurons (38% vs. 50%). Neurons co-reactive for both ChAT and NOS accounted for about 3% in both regions, whereas neurons negative for both enzymes accounted for 7% in the small intestine and 8% in the large intestine. Co-staining with NF revealed that, in both small and large intestine, ChAT+/NOS+ neurons were either spiny (type I) neurons or displayed smaller perikarya that were weakly or not NF-stained. Of all spiny neurons, almost one third was co-reactive for ChAT and NOS, whereas nearly two thirds were positive only for NOS. Neurons negative for both ChAT and NOS were heterogeneous in size and NF reactivity. Thus, neither the co-existence nor the co-absence of ChAT and NOS in human myenteric neurons is indicative for particular neuron types, with several qualitative and quantitative parameters showing a wide range of interindividual variability.

  9. The achievement of sustainable mobility requires the co-existence of numerous energy carriers

    Energy Technology Data Exchange (ETDEWEB)

    Gilpin, Geoffrey; Holden, Erling

    2010-07-01

    Full text: Recent discussions concerning the decarbonisation of the transport sector facilitated by a transition from fossil fuel based transport to a more environmentally benign form of sustainable mobility tend to oversimplify the situation by suggesting a hierarchical evolution of alternative transport fuels. This is highlighted by the linear segregation of biofuel research and development into generations, now standing at current 1st generation-, through to proposed 4th generation biofuels, and with the assumption that hydrogen and electric based modes of transportation will eventually exclude, or greatly minimize, the need for other alternatives in the future. This view of the evolution of future transport fuels is counterproductive to the philosophy of industrial ecology, and its overlying goal of achieving sustainability. Through a review of relevant literature resources the field of industrial ecology and the concept of sustainable mobility is discussed. The criteria by which the sustainability of proposed alternative energy carriers is presented, and the application and validity of developed life-cycle-assessment methodology is reviewed, and argued for as the best available means by which to evaluate existing and proposed energy carriers. A brief review is then presented for the potential of, and limiting factors to current and proposed alternative transport fuels, and thereby clarifies the necessity of adopting a more relaxed view towards the future of sustainable transport fuels. The term 'fuel mosaic' is introduced to describe this future scenario in which fossil fuels co-exist alongside hydrogen, electricity, and biofuels as energy carriers. The variety of energy carriers is required by the presence of varied transport applications, technologies, and their limited factors of production. With this knowledge and the lack of realistic alternative technologies or modes of transportation, and coupled with the expected increase in demand for these

  10. Transovarial Transmission of Co-Existing Orientia tsutsugamushi Genotypes in Laboratory-Reared Leptotrombidium imphalum.

    Science.gov (United States)

    Takhampunya, Ratree; Tippayachai, Bousaraporn; Korkusol, Achareeya; Promsathaporn, Sommai; Leepitakrat, Surachai; Sinwat, Warattaya; Schuster, Anthony L; Richards, Allen L

    2016-01-01

    The co-evolution of Orientia tsutsugamushi and its vector/host Leptotrombidium mites is important for this bacterium to survive and exist in its environment. The data in this study demonstrated that O. tsutsugamushi has adapted to take advantage of the parasitic nature of the host's larval stage and thus increase its chance of transmission to a vertebrate host and potentially to other vector mites by increasing its density at the time of transmission. Our data demonstrated that during the larval stage the density of O. tsutsugamushi was at its highest level compared to other life stages (Kruskal-Wallis, p transmission from the Leptotrombidium imphalum, lines Li-3 and Li-5. No sequence difference of 56-kDa TSA gene (variable domain I-III, 765 bp) was observed between the UT302-like genotype found in mothers and their offspring (100% identity). However, one or two nonsynonymous mutations in the 56-kDa TSA gene were observed in the Karp-like genotypes found in the F1 offspring with a percent difference ranging from 0.13 to 0.26 for nucleotide sequences and from 0.39 to 0.78 for amino acid sequences. Additionally, the composition of co-existing O. tsutsugamushi genotypes was maintained in L. imphalum lines through transsovarial and transstadial transmission processes; however, the proportion of these genotypes in each stage varied (larva, nymph, adult). These results show some of the key characteristics of O. tsutsugamushi maintenance within and transmission among its vector/host L. imphalum.

  11. Co-Existence of Acinic Cell Carcinoma - Papillary Cystic Variant and Extrapulmonary Tuberculosis - Report of A Case with Brief Review.

    Science.gov (United States)

    Amita, Krishnappa; Vijayshankar, Shivshankar; Sanjay, Manchaiah

    2015-09-01

    Tuberculosis (TB) and cancer are two lethal diseases causing significant morbidity and mortality in developing countries like India. Co-existence of these two disease lead to diagnostic dielemma among the clinicians. Overlapping clinical manifestations lead to delay in diagnosis. We report a case of acinic cell carcinoma -papillary cystic variant of the salivary gland and extra pulmonary tuberculosis in a young female. We emphasize the importance of the awareness of the co-existence of these two diseases and the role of fine needle aspiration cytology in the initial diagnosis.

  12. Water-gas shift reaction on CuO-ZnO catalysts: I. Structure and catalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Kalchev, M.G.; Andreev, A.A. [Institute of Catalysis, Sofia (Bulgaria); Zotov, N.S. [Institute of Applied Mineralogy, Sofia (Bulgaria)

    1995-11-01

    The physicochemical properties of CuO-ZnO samples with different CuO contents were investgated by a complex of physical methods: DSC, XPS, EPR, TPR, and XRD. The samples containing {approximately}25 wt % CuO exhibited a maximum catalytic activity in the water-gas shift reaction. The catalytic activity was attributed to copper ions aggregated on the highly dispersed and defective CuO surface and to an anion-modified ZnO surface. Aggregates of copper ions, formed on metal species and probably modified with hydroxyl and carbonate groups, were shown to play a decisive role in the catalytic activity of the samples containing more than 15 wt % CuO.

  13. Catalytic behavior of metallic particles in anisotropic etching of Ge(100) surfaces in water mediated by dissolved oxygen

    Science.gov (United States)

    Kawase, Tatsuya; Mura, Atsushi; Nishitani, Keisuke; Kawai, Yoshie; Kawai, Kentaro; Uchikoshi, Junichi; Morita, Mizuho; Arima, Kenta

    2012-06-01

    The authors demonstrate that Ge(100) surfaces containing metallic particles are etched anisotropically in water. This originates from the catalytic reduction of dissolved oxygen (O2) in water to water molecules (H2O) on the metallic particles, which is followed by the enhanced oxidation of Ge around the particles. The soluble nature of Ge oxide (GeO2) in water promotes the formation of inverted pyramidal etch pits composed of (111) microfacets. On the basis of the results, the authors propose strategies for avoiding unwanted surface roughening during the wet cleaning of Ge.

  14. Photo-catalytic reactors for in-building grey water reuse. Comparison with biological processes and market potential

    Energy Technology Data Exchange (ETDEWEB)

    Jefferson, B.; Murray, C.; Diaper, C.; Parsons, S.A.; Jeffrey, P. [School of Water Sciences, Cranfield Univ., Cranfield, Bedfordshire (United Kingdom); Bedel, C. [Dept. of Industrial Process, National Inst. of Applied Sciences (France); Centeno, C. [Dept. of the Faculty of Engineering, Univ. of Santo Tomas, Manila (Philippines)

    2003-07-01

    Photo catalytic reactors potentially have a market in the reuse of grey water as they do not suffer from problems associated with toxic shocks and can be compact. The process is dependant upon the ratio of TOC to TiO{sub 2} concentration such that a greater proportion of the feed is degraded when either are increased. Economic assessment of grey water recycling showed both scale of operation and regional location to be the two most important factors in deciding the financial acceptability of any reuse technology. Overall the assessment suggested that photo catalytic oxidation (PCO) technology was suitable for grey water recycling and that the technology should be marketed at large buildings such as residential accommodation and offices. (orig.)

  15. Simultaneous Determination of Iron and Manganese in Water Using Artificial Neural Network Catalytic Spectrophotometric Method

    Institute of Scientific and Technical Information of China (English)

    JI Hongwei; XU Yan; LI Shuang; XIN Huizhen; CAO Hengxia

    2012-01-01

    A new analytical method using Back-Propagation(BP)artificial neural network and kinetic spectrophotometry for simultaneous determination of iron and magnesium in tap water,the Yellow River water and seawater is established.By conditional experiments,the optimum analytical conditions and parameters are obtained.Levenberg-Marquart(L-M)algorithm is used for calculation in BP neural network.The topological structure of three-layer BP ANN network architecture is chosen as 15-16-2(nodes).The initial value of gradient coefficientμ is fixed at 0.001 and the increase factor and reduction factor ofμ take the default values of the system.The data are processed by computers with our own programs written in MATLAB 7.0.The relative standard deviation of the calculated results for iron and manganese is 2.30% and 2.67% respectively.The results of standard addition method show that for the tap water,the recoveries of iron and manganese are in the ranges of 98.0%-104.3% and 96.5%-104.5%,and the RSD is in the range of 0.23%-0.98%;for the Yellow River water(Lijin district of Shandong Province),the recoveries of iron and manganese are in the ranges of 96.0%-101.0% and 98.7%-104.2%,and the RSD is in the range of 0.13%-2.52%;for the seawater in Qingdao offshore,the recoveries of iron and manganese are in the ranges of 95.3%-104.8% and 95.3%-104.7%,and the RSD is in the range of 0.14%-2.66%.It is found that 21 common cations and anions do not interfere with the determination of iron and manganese under the optimum experimental conditions.This method exhibits good reproducibility and high accuracy in the determination of iron and manganese and can be used for the simultaneous determination of iron and manganese in tap water and natural water.By using the established ANN-catalytic spectrophotometric method,the iron and manganese concentrations of the surface seawater at 11 sites in Qingdao offshore are determined and the level distribution maps of

  16. Wet peroxide oxidation and catalytic wet oxidation of stripped sour water produced during oil shale refining.

    Science.gov (United States)

    Prasad, Jaidev; Tardio, James; Jani, Harit; Bhargava, Suresh K; Akolekar, Deepak B; Grocott, Stephen C

    2007-07-31

    Catalytic wet oxidation (CWO) and wet peroxide oxidation (WPO) of stripped sour water (SSW) from an oil shale refinery was investigated. Greater than 70% total organic carbon (TOC) removal from SSW was achieved using Cu(NO(3))(2) catalysed WO under the following conditions using a glass lined reaction vessel: 200 degrees C, pO(2)=0.5MPa, 3h, [Cu(NO(3))(2)]=67mmol/L. Significant TOC removal ( approximately 31%) also occurred in the system without added oxygen. It is proposed that this is predominantly due to copper catalysed oxidative decarboxylation of organics in SSW based on observed changes in copper oxidation state. Greater than 80% TOC removal was achieved using WPO under the following conditions: 150 degrees C, t=1.5h, [H(2)O(2)]=64g/L. Significantly more TOC could be removed from SSW by adding H(2)O(2) in small doses as opposed to adding the same total amount in one single dose. It was concluded that WPO was a far more effective process for removing odorous compounds from SSW.

  17. Catalytic hydrodechlorination of trichloroethylene in water with supported CMC-stabilized palladium nanoparticles.

    Science.gov (United States)

    Zhang, Man; Bacik, Deborah B; Roberts, Christopher B; Zhao, Dongye

    2013-07-01

    In this work, we developed and tested a new class of supported Pd catalysts by immobilizing CMC (carboxymethyl cellulose) stabilized Pd nanoparticles onto alumina support. The alumina supported Pd nanoparticles were able to facilitate rapid and complete hydrodechlorination of TCE (trichloroethylene) without intermediate by-products detected. With a Pd mass loading of 0.33 wt% of the alumina mass, the observed pseudo first order reaction rate constant, k(obs), for the catalyst was increased from 28 to 109 L/min/g when CMC concentration was raised from 0.005 to 0.15 wt%. The activity increase was in accord with an increase of the Pd dispersion (measured via CO chemisorption) from 30.4% to 45.1%. Compared to the commercial alumina supported Pd, which has a lower Pd dispersion of 21%, our CMC-stabilized Pd nanoparticles offered more than 7 times greater activity. Pre-calcination treatment of the supported catalyst resulted in minor drop in activity, yet greatly reduced bleeding (catalytic activity. The alumina supported CMC-stabilized Pd nanoparticles may serve as a class of more effective catalysts for water treatment uses.

  18. Single-stage temperature-controllable water gas shift reactor with catalytic nickel plates

    Science.gov (United States)

    Park, Jin-Woo; Lee, Sung-Wook; Lee, Chun-Boo; Park, Jong-Soo; Lee, Dong-Wook; Kim, Sung-Hyun; Kim, Sung-Soo; Ryi, Shin-Kun

    2014-02-01

    In this study, a microstructured reactor with catalytic nickel plates is newly designed and developed for proper heat management in an exothermic water gas shift WGS reaction. The reactor is designed to increase the reactor capacity simply by numbering-up a set of a catalyst layers and heat exchanger layers. The WGS reactor is built up with two sets of a catalyst layers and heat exchanger layers. The performance of the reactor is verified by WGS testing with the variation of the furnace temperatures, gas hourly space velocity (GHSV) and coolant (N2) flow rate. At a GHSV of 10,000 h-1, CO conversion reaches the equilibrium value with a CH4 selectivity of ≤0.5% at the furnace temperature of ≥375 °C. At high GHSV (40,000 h-1), CO conversion decreases considerably because of the heat from the exothermic WGS reaction at a large reactants mass. By increasing the coolant flow rate, the heat from the WGS reaction is properly managed, leading an increase of the CO conversion to the equilibrium value at GHSV of 40,000 h-1.

  19. Principles of water oxidation and O2-based hydrocarbon transformation by multinuclear catalytic sites

    Energy Technology Data Exchange (ETDEWEB)

    Musaev, Djamaladdin G [Chemistry, Emory University; Hill, Craig L [Chemistry, Emory University; Morokuma, Keiji [Chemistry, Emory University

    2014-10-28

    Abstract The central thrust of this integrated experimental and computational research program was to obtain an atomistic-level understanding of the structural and dynamic factors underlying the design of catalysts for water oxidation and selective reductant-free O2-based transformations. The focus was on oxidatively robust polyoxometalate (POM) complexes in which a catalytic active site interacts with proximal metal centers in a synergistic manner. Thirty five publications in high-impact journals arose from this grant. I. Developing an oxidatively and hydrolytically stable and fast water oxidation catalyst (WOC), a central need in the production of green fuels using water as a reductant, has proven particularly challenging. During this grant period we have designed and investigated several carbon-free, molecular (homogenous), oxidatively and hydrolytically stable WOCs, including the Rb8K2[{Ru4O4(OH)2(H2O)4}(γ-SiW10O36)2]·25H2O (1) and [Co4(H2O)2(α-PW9O34)2]10- (2). Although complex 1 is fast, oxidatively and hydrolytically stable WOC, Ru is neither abundant nor inexpensive. Therefore, development of a stable and fast carbon-free homogenous WOC, based on earth-abundant elements became our highest priority. In 2010, we reported the first such catalyst, complex 2. This complex is substantially faster than 1 and stable under homogeneous conditions. Recently, we have extended our efforts and reported a V2-analog of the complex 2, i.e. [Co4(H2O)2(α-VW9O34)2]10- (3), which shows an even greater stability and reactivity. We succeeded in: (a) immobilizing catalysts 1 and 2 on the surface of various electrodes, and (b) elucidating the mechanism of O2 formation and release from complex 1, as well as the Mn4O4L6 “cubane” cluster. We have shown that the direct O-O bond formation is the most likely pathway for O2 formation during water oxidation catalyzed by 1. II. Oxo transfer catalysts that contain two proximal and synergistically interacting redox active metal

  20. A new class of photo-catalytic materials and a novel principle for efficient water splitting under infrared and visible light - MgB2 as unexpected example

    OpenAIRE

    Kravets, V. G.; A. N. Grigorenko

    2015-01-01

    Water splitting is unanimously recognized as environment friendly, potentially low cost and renewable energy solution based on the future hydrogen economy. Especially appealing is photo-catalytic water splitting whereby a suitably chosen catalyst dramatically improves efficiency of the hydrogen production driven by direct sunlight and allows it to happen even at zero driving potential. Here, we suggest a new class of stable photo-catalysts and the corresponding principle for catalytic water s...

  1. A study of different supports for the catalytic reduction of nitrates from natural water with a continuous reactor

    OpenAIRE

    Palomares, A.E.; Franch, C.; Corma,A.

    2011-01-01

    The aim of this work is to study the activity for the nitrate catalytic reduction in natural water, using a continuous stirred tank reactor, of Pd/Cu and Pd/Sn catalysts supported on different materials. The studied supports are: -Al2O3 (commercial), active carbon, graphite, hydrotalcite and alumina synthesized in our laboratory with a high surface area. The activity and selectivity of the catalysts supported on these materials have been compared. The best results have been obtain...

  2. Stable co-existence of separate replicons in Escherichia coli is dependent on once-per-cell-cycle initiation

    DEFF Research Database (Denmark)

    Skarstad, K.; Løbner-Olesen, Anders

    2003-01-01

    C sequences (mini-chromosomes) are also initiated in synchrony with the eight chromosomal origins. We demonstrate that specific inactivation of newly formed, hemimethylated origins (sequestration) was required for the stable coexistence of oriC-dependent replicons. Cells in which initiations were not confined...... to a short interval in the cell cycle (carrying mutations in sequestration or initiation genes or expressing excess initiator protein) could not support stable co-existence of several oriC-dependent replicons. The results show that such stable co-existence of oriC-dependent replicons; is dependent on both...... a period of sequestration that is longer than the initiation interval and a reduction of the initiation potential during the sequestration period. These regulatory requirements are the same as those required to confine initiation of each replicon to once, and only once, per cell cycle....

  3. Dynamical co-existence of excitons and free carriers in perovskite probed by density-resolved fluorescent spectroscopic method

    CERN Document Server

    Wang, Wei; Wang, Xiangyuan; Lv, Yanping; Wang, Shufeng; Wang, Kai; Shi, Yantao; Xiao, Lixin; Chen, Zhijian; Gong, Qihuang

    2016-01-01

    Using transient fluorescent spectra at time-zero, we develop a density-resolved fluorescent spectroscopic method for investigating photoproducts in CH3NH3PbI3 perovskite and related photophysics. The density dependent dynamical co-existence of excitons and free carriers over a wide density range is experimentally observed for the first time. The exciton binding energy (EB) and the effective mass of electron-hole pair can be estimated based on such co-existence. No ionic polarization is found contributing to photophysical behavior. It also solves the conflict between the large experimentally measured EB and the small predicted values. The spectroscopic method also helps to detect the true free carrier density under continuous illumination without the interference of ionic conductivity. Our methods and results profoundly enrich the study and understanding of the photophysics in perovskite materials for photovoltaic applications.

  4. Effect of Water Vapour on the Acidity of ZSM-5Zeolite Used for Catalytic Cracking of Naphtha to Manufacture Ethylene and Propylene

    Institute of Scientific and Technical Information of China (English)

    Ma Guangwei; Xiao Jingxian; ZhangHuining; Xie Zaiku

    2008-01-01

    The change in acidity of the ZSM-5 zeolite was investigated after it was treated with water vapour,and its capability on ammonia adsorption was also studied after having adsorbed water vapour.The effect of water vapour on products distribution was studied during catalytic cracking of naphtha,the changes in the adsorption ability and catalytic performance of the ZSM-5 zeolite was investigated after the catalyst was loaded with phosphorus species.These results all indicated that water vapour could reduce the acid strength and acid density of ZSM-5 zeolite and affect the capability of ZSM-5 on adsorption of gases,therefore the activated energy contributed by the ZSM-5 zeolite to the catalytic cracking reaction would be low to prevent the feedstock from deepened catalytic cracking and coke formation.

  5. Socio-nutritional Variables of Mazahua Households. Co-existing Preschool Malnourished with Obesity Mothers or not Obesity Mothers

    OpenAIRE

    Conzuelo González, Viridiana Vanessa; Viczcarra Bordi, Ivonne

    2009-01-01

    The first objective was to know the prevalence of Mazahua households living in extreme poverty, and where malnourished preschool children co-exist with overweight and obese mothers, in this study three socio-nutritional variables were compared (family income, mother's education and nutritional adequacy of the daily diet) among these households and those formed by malnourished children and non-obese mothers. A transversal study was carried out (2006-2007) in the Mazahua community of San Franci...

  6. Co-Existence of Modified Chaplygin Gas and Other Dark Energies in the Framework of Fractal Universe

    Science.gov (United States)

    Maity, Sayani; Debnath, Ujjal

    2016-05-01

    In this work, we consider a non-flat universe in the framework of fractal cosmology. We have investigated the co-existence of different kinds of dark energy models such as tachyonic field, DBI-essence, hessence, k-essence, dilaton, quintessence with the modified Chaplygin gas (MCG) in fractal universe and obtained the statefinder parameters. The natures of the scalar fields and the concerned potentials have been analyzed by the correspondence scenario in the fractal universe.

  7. Patchiness and co-existence of indigenous and invasive mussels at small spatial scales: the interaction of facilitation and competition.

    Science.gov (United States)

    Erlandsson, Johan; McQuaid, Christopher D; Sköld, Martin

    2011-01-01

    Ecological theory predicts that two species with similar requirements will fail to show long-term co-existence in situations where shared resources are limiting, especially at spatial scales that are small relative to the size of the organisms. Two species of intertidal mussels, the indigenous Perna perna and the invasive Mytilus galloprovincialis, form mixed beds on the south coast of South Africa in a situation that has been stable for several generations of these species, even though these populations are often limited by the availability of space. We examined the spatial structure of these species where they co-exist at small spatial scales in the absence of apparent environmental heterogeneity at two sites, testing: whether conspecific aggregation of mussels can occur (using spatial Monte-Carlo tests); the degree of patchiness (using Korcak B patchiness exponent), and whether there was a relationship between percent cover and patchiness. We found that under certain circumstances there is non-random conspecific aggregation, but that in other circumstances there may be random distribution (i.e. the two species are mixed), so that spatial patterns are context-dependent. The relative cover of the species differed between sites, and within each site, the species with higher cover showed low Korcak B values (indicating low patchiness, i.e. the existence of fewer, larger patches), while the less abundant species showed the reverse, i.e. high patchiness. This relationship did not hold for either species within sites. We conclude that co-existence between these mussels is possible, even at small spatial scales because each species is an ecological engineer and, while they have been shown to compete for space, this is preceded by initial facilitation. We suggest that a patchy pattern of co-existence is possible because of a balance between direct (competitive) and indirect (facilitative) interactions.

  8. Patchiness and co-existence of indigenous and invasive mussels at small spatial scales: the interaction of facilitation and competition.

    Directory of Open Access Journals (Sweden)

    Johan Erlandsson

    Full Text Available Ecological theory predicts that two species with similar requirements will fail to show long-term co-existence in situations where shared resources are limiting, especially at spatial scales that are small relative to the size of the organisms. Two species of intertidal mussels, the indigenous Perna perna and the invasive Mytilus galloprovincialis, form mixed beds on the south coast of South Africa in a situation that has been stable for several generations of these species, even though these populations are often limited by the availability of space. We examined the spatial structure of these species where they co-exist at small spatial scales in the absence of apparent environmental heterogeneity at two sites, testing: whether conspecific aggregation of mussels can occur (using spatial Monte-Carlo tests; the degree of patchiness (using Korcak B patchiness exponent, and whether there was a relationship between percent cover and patchiness. We found that under certain circumstances there is non-random conspecific aggregation, but that in other circumstances there may be random distribution (i.e. the two species are mixed, so that spatial patterns are context-dependent. The relative cover of the species differed between sites, and within each site, the species with higher cover showed low Korcak B values (indicating low patchiness, i.e. the existence of fewer, larger patches, while the less abundant species showed the reverse, i.e. high patchiness. This relationship did not hold for either species within sites. We conclude that co-existence between these mussels is possible, even at small spatial scales because each species is an ecological engineer and, while they have been shown to compete for space, this is preceded by initial facilitation. We suggest that a patchy pattern of co-existence is possible because of a balance between direct (competitive and indirect (facilitative interactions.

  9. Effect of Co-Existing Biologically Relevant Molecules and Ions on DNA Photocleavage Caused by Pyrene and its Derivatives

    Directory of Open Access Journals (Sweden)

    Hongtao Yu

    2005-04-01

    Full Text Available Inorganic ions, coenzymes, amino acids, and saccharides could co-exist with toxic environmental chemicals, such as polycyclic aromatic hydrocarbons (PAHs, in the cell. The presence of these co-existing chemicals can modulate the toxicity of the PAHs. One of the genotoxic effects by PAHs is light-induced cleavage, or photocleavage, of DNA. The effect of inorganic ions I-, Na+, Ca2+, Mg2+, Fe3+, Mn2+, Cu2+, and Zn2+ and biological molecules riboflavin, histidine, mannitol, nicotinamide adenine dinucleotide (NAD, glutathione, and glutamic acid on the DNA photocleavage by pyrene, 1-hydroxypyrene (1-HP, and 1-aminopyrene (1-AP, is studied. The non-transition metal ions Na+, Ca2+, and Mg2+, usually have very little inhibitory effects, while the transition metal ions Fe3+, Cu2+, and Zn2+ enhance, Mn2+ inhibits the DNA photocleavage. The effect by biological molecules is complex, depending on the photochemical reaction mechanisms of the compounds tested (1-AP, 1-HP and pyrene and on the chemical nature of the added biological molecules. Riboflavin, histidine, and mannitol enhance DNA photocleavage by all three compounds, except that mannitol has no effect on the photocleavage of DNA by pyrene. Glutathione inhibits the DNA photocleavage by 1-AP and 1-HP, but has no effect on that by pyrene. NAD enhances the DNA photocleavage by 1-AP, but has no effect on that by 1-HP and pyrene. Glutamic acid enhances the DNA photocleavage by 1-AP and pyrene, but inhibits that by 1-HP. These results show that the co-existing chemicals may have a profound effect on the toxicity of PAHs, or possibly on the toxicity of many other chemicals. Therefore, if one studies the toxic effects of PAHs or other toxic chemicals, the effect of the co-existing chemicals or ions needs to be considered.

  10. Principles of water oxidation and O2-based hydrocarbon transformation by multinuclear catalytic sites

    Energy Technology Data Exchange (ETDEWEB)

    Musaev, Djamaladdin G [Chemistry, Emory University; Hill, Craig L [Chemistry, Emory University; Morokuma, Keiji [Chemistry, Emory University

    2014-10-28

    Abstract The central thrust of this integrated experimental and computational research program was to obtain an atomistic-level understanding of the structural and dynamic factors underlying the design of catalysts for water oxidation and selective reductant-free O2-based transformations. The focus was on oxidatively robust polyoxometalate (POM) complexes in which a catalytic active site interacts with proximal metal centers in a synergistic manner. Thirty five publications in high-impact journals arose from this grant. I. Developing an oxidatively and hydrolytically stable and fast water oxidation catalyst (WOC), a central need in the production of green fuels using water as a reductant, has proven particularly challenging. During this grant period we have designed and investigated several carbon-free, molecular (homogenous), oxidatively and hydrolytically stable WOCs, including the Rb8K2[{Ru4O4(OH)2(H2O)4}(γ-SiW10O36)2]·25H2O (1) and [Co4(H2O)2(α-PW9O34)2]10- (2). Although complex 1 is fast, oxidatively and hydrolytically stable WOC, Ru is neither abundant nor inexpensive. Therefore, development of a stable and fast carbon-free homogenous WOC, based on earth-abundant elements became our highest priority. In 2010, we reported the first such catalyst, complex 2. This complex is substantially faster than 1 and stable under homogeneous conditions. Recently, we have extended our efforts and reported a V2-analog of the complex 2, i.e. [Co4(H2O)2(α-VW9O34)2]10- (3), which shows an even greater stability and reactivity. We succeeded in: (a) immobilizing catalysts 1 and 2 on the surface of various electrodes, and (b) elucidating the mechanism of O2 formation and release from complex 1, as well as the Mn4O4L6 “cubane” cluster. We have shown that the direct O-O bond formation is the most likely pathway for O2 formation during water oxidation catalyzed by 1. II. Oxo transfer catalysts that contain two proximal and synergistically interacting redox active metal

  11. Group acceptance and commitment therapy (ACT) for bipolar disorder and co-existing anxiety - an open pilot study.

    Science.gov (United States)

    Pankowski, Sara; Adler, Mats; Andersson, Gerhard; Lindefors, Nils; Svanborg, Cecilia

    2017-03-01

    Previous studies have supported acceptance and commitment therapy (ACT) for reducing impairment related to various chronic conditions. ACT may possibly be beneficial for bipolar disorder (BD) with co-existing anxiety, which is associated with a poorer treatment outcome. Efforts are needed to identify suitable psychological interventions for BD and co-existing anxiety. In this open clinical trial, we included 26 patients with BD type 1 or 2 at an outpatient psychiatric unit specializing in affective disorders. The intervention consisted of a 12-session manualized group treatment that included psychoeducation, mindfulness, engaging in values-based behaviour, cognitive defusion, acceptance and relapse prevention modules. Participants completed four self-report questionnaires covering anxiety symptoms (Beck Anxiety Inventory - BAI), depressive symptoms (Beck Depression Inventory - BDI-II), quality of life (Quality of Life Inventory - QOLI) and psychological flexibility (Acceptance and Action Questionnaire - AAQ-2) before, during and after the treatment. At post-treatment, the participants reported significant improvements in all outcome measures, with large effects (Cohen's d between 0.73 and 1.98). The mean reduction in anxiety symptoms was 45%. At post-treatment, 96% of the patients were classified as responders on at least one of the outcome measures. A limitation is that the trial is uncontrolled. The results suggest that ACT has the potential to be an effective treatment for BD patients with co-existing anxiety. Further randomized studies are warranted.

  12. Co-existence of Phenylketonuria and Fabry disease on a 3 year-old boy: case report

    Directory of Open Access Journals (Sweden)

    Bonapace Giuseppe

    2010-05-01

    Full Text Available Abstract Background The co-existence of two genetically distinct metabolic disorders in the same patient has rarely been reported. Phenylketonuria (PKU is an inborn error of the metabolism resulting from a phenylalanine hydroxylase deficiency. Fabry disease (FD is an X-linked lysosomal storage disorder due to a deficiency of the enzyme alpha-galactosidase A. Case presentation We report a case of a 3 year- old boy affected by classic PKU and FD, both confirmed by molecular data. The FD was suspected at the age of 21 months on the presence of non-specific GI symptoms (severe abdominal pain and periodically appearance of not specific episodes of gastroenteritis apparently non related to PKU. Conclusion This is the first report of co-existence of FD and PKU, two different congenital inborn of metabolism and in consideration of the prevalence of each disease this chance association is a very unusual event. The co-existence of this diseases made very difficult the correct interpretation of clinical symptoms as lack of appetite, severe abdominal pain and non-specific gastroenteritis episodes. Furthermore, this case report helps to define the early clinical phenotype of FD.

  13. Co-existence of non-alcoholic fatty liver disease and inflammatory bowel disease: A review article

    Science.gov (United States)

    Chao, Che-Yung; Battat, Robert; Al Khoury, Alex; Restellini, Sophie; Sebastiani, Giada; Bessissow, Talat

    2016-01-01

    Emerging data have highlighted the co-existence of non-alcoholic fatty liver disease (NAFLD) and inflammatory bowel disease; both of which are increasingly prevalent disorders with significant complications and impact on future health burden. Cross-section observational studies have shown widely variable prevalence rates of co-existing disease, largely due to differences in disease definition and diagnostic tools utilised in the studies. Age, obesity, insulin resistance and other metabolic conditions are common risks factors in observational studies. However, other studies have also suggested a more dominant role of inflammatory bowel disease related factors such as disease activity, duration, steroid use and prior surgical intervention, in the development of NAFLD. This suggests a potentially more complex pathogenesis and relationship between the two diseases which may be contributed by factors including altered intestinal permeability, gut dysbiosis and chronic inflammatory response. Commonly used immunomodulation agents pose potential hepatic toxicity, however no definitive evidence exist linking them to the development of hepatic steatosis, nor are there any data on the impact of therapy and prognosis in patient with co-existent diseases. Further studies are required to assess the impact and establish appropriate screening and management strategies in order to allow early identification, intervention and improve patient outcomes. PMID:27678354

  14. Co-existence of non-alcoholic fatty liver disease and inflammatory bowel disease: A review article.

    Science.gov (United States)

    Chao, Che-Yung; Battat, Robert; Al Khoury, Alex; Restellini, Sophie; Sebastiani, Giada; Bessissow, Talat

    2016-09-14

    Emerging data have highlighted the co-existence of non-alcoholic fatty liver disease (NAFLD) and inflammatory bowel disease; both of which are increasingly prevalent disorders with significant complications and impact on future health burden. Cross-section observational studies have shown widely variable prevalence rates of co-existing disease, largely due to differences in disease definition and diagnostic tools utilised in the studies. Age, obesity, insulin resistance and other metabolic conditions are common risks factors in observational studies. However, other studies have also suggested a more dominant role of inflammatory bowel disease related factors such as disease activity, duration, steroid use and prior surgical intervention, in the development of NAFLD. This suggests a potentially more complex pathogenesis and relationship between the two diseases which may be contributed by factors including altered intestinal permeability, gut dysbiosis and chronic inflammatory response. Commonly used immunomodulation agents pose potential hepatic toxicity, however no definitive evidence exist linking them to the development of hepatic steatosis, nor are there any data on the impact of therapy and prognosis in patient with co-existent diseases. Further studies are required to assess the impact and establish appropriate screening and management strategies in order to allow early identification, intervention and improve patient outcomes.

  15. The catalytic effect of water, water dimers and water trimers on H2S + (3)O2 formation by the HO2 + HS reaction under tropospheric conditions.

    Science.gov (United States)

    Zhang, Tianlei; Yang, Chen; Feng, Xukai; Kang, Jiaxin; Song, Liang; Lu, Yousong; Wang, Zhiyin; Xu, Qiong; Wang, Wenliang; Wang, Zhuqing

    2016-06-29

    In this article, the reaction mechanisms of H2S + (3)O2 formation by the HO2 + HS reaction without and with catalyst X (X = H2O, (H2O)2 and (H2O)3) have been investigated theoretically at the CCSD(T)/6-311++G(3df,2pd)//B3LYP/6-311+G(2df,2p) level of theory, coupled with rate constant calculations by using conventional transition state theory. Our results show that in the presence of catalyst X (X = H2O, (H2O)2 and (H2O)3) into the channel of H2S + (3)O2 formation, the reactions between the SH radical and HO2(H2O)n (n = 1-3) complexes are more favorable than the corresponding reactions of the HO2 radical with HS(H2O)n (n = 1-3) complexes due to the lower barrier of the former reactions and the higher concentrations of HO2(H2O)n (n = 1-3) complexes. Meanwhile, the catalytic effect of water, water dimers and water trimers is mainly taken from the contribution of a single water vapor molecule, since the total effective rate constant of HO2H2O + HS and H2OHO2 + HS reactions was, respectively, larger by 7-9 and 9-12 orders of magnitude than that of SH + HO2(H2O)2 and SH + HO2(H2O)3 reactions. Besides, the enhancement factor of water vapor is only 0.37% at 240 K, while at high temperatures, such as 425 K, the positive water vapor effect is enhanced up to 38.00%, indicating that at high temperatures the positive water effect is obvious under atmospheric conditions. Overall, these results show how water and water clusters catalyze the gas phase reactions under atmospheric conditions.

  16. Removal of Disinfection By-Products from Contaminated Water Using a Synthetic Goethite Catalyst via Catalytic Ozonation and a Biofiltration System

    Directory of Open Access Journals (Sweden)

    Yu-Hsiang Wang

    2014-09-01

    Full Text Available The effects of synthetic goethite (α-FeOOH used as the catalyst in catalytic ozonation for the degradation of disinfection by-product (DBP precursors are investigated. A biofiltration column applied following the catalytic ozonation process is used to evaluate the efficiency of removing DBP precursors via biotreatment. Ozone can rapidly react with aromatic compounds and oxidize organic compounds, resulting in a decrease in the fluorescence intensity of dissolved organic matter (DOM. In addition, catalytic ozonation can break down large organic molecules, which causes a blue shift in the emission-excitation matrix spectra. Water treated with catalytic ozonation is composed of low-molecular structures, including soluble microbial products (SMPs and other aromatic proteins (APs. The DOM in SMPs and APs is removed by subsequent biofiltration. Catalytic ozonation has a higher removal efficiency for dissolved organic carbon and higher ultraviolet absorbance at 254 nm compared to those of ozonation without a catalyst. The use of catalytic ozonation and subsequent biofiltration leads to a lower DBP formation potential during chlorination compared to that obtained using ozonation and catalytic ozonation alone. Regarding DBP species during chlorination, the bromine incorporation factor (BIF of trihalomethanes and haloacetic acids increases with increasing catalyst dosage in catalytic ozonation. Moreover, the highest BIF is obtained for catalytic ozonation and subsequent biofiltration.

  17. Preparation of Molecular Sieve Catalyst and Application in the Catalytic Oxidation Treatment of Waste Water

    Institute of Scientific and Technical Information of China (English)

    WANG RongMin; XIE Xin; HE YuFeng; WANG YunPu; HE NaiPu; ZHANG ZhengLin; SONG PengFei; LIU WenJun

    2001-01-01

    @@ Citric acid is an important additive in foods, cosmetics, medicine and so on, but it discharges about 10 ton of factory effluent when 1 ton of citric acid is produced. The COD of the factory effluent is near 20000 mg/L. The treatment of citric acid factory effluent is a serious problem in environmental chemistry. It is found that molecular sieve support metal complexes have high catalytic activity in aerobic oxidation of alkene [1,2]. In this paper, a kind of molecular sieve catalyst was prepared. The catalyst was used for the treatment of citric acid factory effluent by method of catalytic oxygen oxidation.

  18. FREQUENCY CATASTROPHE AND CO-EXISTING ATTRACTORS IN A CELL Ca2+ NONLINEAR OSCILLATION MODEL WITH TIME DELAY*

    Institute of Scientific and Technical Information of China (English)

    应阳君; 黄祖洽

    2001-01-01

    Frequency catastrophe is found in a cell Ca2+ nonlinear oscillation model with time delay. The relation of the frequency transition to the time delay is studied by numerical simulations and theoretical analysis. There is a range of parameters in which two kinds of attractors with great frequency differences co-exist in the system. Along with parameter changes, a critical phenomenon occurs and the oscillation frequency changes greatly. This mechanism helps us to deepen the understanding of the complex dynamics of delay systems, and might be of some meaning in cell signalling.

  19. NUMERICAL COMPUTATIONS OF CO-EXISTING SUPER-CRITICAL AND SUB-CRITICAL FLOWS BASED UPON CRD SCHEMES

    Science.gov (United States)

    Horie, Katsuya; Okamura, Seiji; Kobayashi, Yusuke; Hyodo, Makoto; Hida, Yoshihisa; Nishimoto, Naoshi; Mori, Akio

    Stream flows in steep gradient bed form complicating flow configurations, where co-exist super-critical and sub-critical flows. Computing numerically such flows are the key to successful river management. This study applied CRD schemes to 1D and 2D stream flow computations and proposed genuine ways to eliminate expansion shock waves. Through various cases of computing stream flows conducted, CRD schemes showed that i) conservativeness of discharge and accuracy of four significant figures are ensured, ii) artificial viscosity is not explicitly used for computational stabilization, and thus iii) 1D and 2D computations based upon CRD schemes are applicable to evaluating complicating stream flows for river management.

  20. Environmental Topology and Water Availability Modulates the Catalytic Activity of β-Galactosidase Entrapped in a Nanosporous Silicate Matrix

    OpenAIRE

    M. Ines Burgos; Manuel I. Velasco; Acosta, Rodolfo H.; María A. Perillo

    2016-01-01

    In the present work we studied the catalytic activity of E. coli β-Gal confined in a nanoporous silicate matrix (Eβ-Gal) at different times after the beginning of the sol-gel polymerization process. Enzyme kinetic experiments with two substrates (ONPG and PNPG) that differed in the rate-limiting steps of the reaction mechanism for their β-Gal-catalyzed hydrolysis, measurements of transverse relaxation times (T 2 ) of water protons through 1H-NMR, and scanning electron microscopy analysis of t...

  1. High catalytic activity of heteropolynuclear cyanide complexes containing cobalt and platinum ions: visible-light driven water oxidation.

    Science.gov (United States)

    Yamada, Yusuke; Oyama, Kohei; Gates, Rachel; Fukuzumi, Shunichi

    2015-05-04

    A near-stoichiometric amount of O2 was evolved as observed in the visible-light irradiation of an aqueous buffer (pH 8) containing [Ru(II) (2,2'-bipyridine)3 ] as a photosensitizer, Na2 S2 O8 as a sacrificial electron acceptor, and a heteropolynuclear cyanide complex as a water-oxidation catalyst. The heteropolynuclear cyanide complexes exhibited higher catalytic activity than a polynuclear cyanide complex containing only Co(III) or Pt(IV) ions as C-bound metal ions. The origin of the synergistic effect between Co and Pt ions is discussed in relation to electronic and local atomic structures of the complexes.

  2. Non-Catalytic and MgSO4 - Catalyst based Degradation of Glycerol in Subcritical and Supercritical Water Media

    Directory of Open Access Journals (Sweden)

    Mahfud Mahfud

    2011-02-01

    Full Text Available This research aims to study the glycerol degradation reaction in subcritical and supercritical water media. The degradation of glycerol into other products was performed both with sulphate salt catalysts and without catalyst. The reactant was made from glycerol and water with the mass ratio of 1:10. The experiments were carried out using a batch reactor at a constant pressure of 250 kgf/cm2, with the temperature range of 200-400oC, reaction time of 30 minutes, and catalyst mol ratio in glycerol of 1:10 and 1:8. The products of the non-catalytic glycerol degradation were acetaldehyde, methanol, and ethanol. The use of sulphate salt as catalyst has high selectivity to acetaldehyde and still allows the formation alcohol product in small quantities. The mechanism of ionic reaction and free radical reaction can occur at lower temperature in hydrothermal area or subcritical water. Conversion of glycerol on catalytic reaction showed a higher yield when compared with the reaction performed without catalyst

  3. A Broad Spectrum Catalytic System for Removal of Toxic Organics from Water by Deep Oxidation - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Ayusman

    2000-12-01

    A most pressing need for the DOE environmental management program is the removal of toxic organic compounds present in groundwater and soil at specific DOE sites. While several remediation procedures have been proposed, they suffer from one or more drawbacks. The objective of the present research was to develop new catalytic procedures for the removal of toxic organic compounds from the environment through their deep oxidation to harmless products. In water, metallic palladium was found to catalyze the deep oxidation of a wide variety of toxic organic compounds by dioxygen at 80-90 C in the presence of carbon monoxide or dihydrogen. Several classes of organic compounds were examined: benzene, phenol and substituted phenols, nitro and halo organics, organophosphorus, and organosulfur compounds. In every case, deep oxidation to carbon monoxide, carbon dioxide, and water occurred in high yields, resulting in up to several hundred turnovers over a 24 hour period. For substrates susceptible to hydrogenation, the conversions were generally high with dihydrogen than with carbon monoxide. It is clear from the results obtained that we have discovered an exceptionally versatile catalytic system for the deep oxidation of toxic organic compounds in water. This system possesses several attractive features not found simultaneously in other reported systems. These are (a) the ability to directly utilize dioxygen as the oxidant, (b) the ability to carry out the deep oxidation of a particularly wide range of functional organics, and (c) the ease of recovery of the catalyst by simple filtration.

  4. Effect of NO2 and water on the catalytic oxidation of soot

    DEFF Research Database (Denmark)

    Christensen, Jakob Munkholt; Grunwaldt, Jan-Dierk; Jensen, Anker Degn

    2017-01-01

    from the oxide, and where the reaction thus has reached the zero order kinetics regime in the gaseous reactant. In loose contact with a catalyst the presence of NO2 causes a pronounced enhancement of the oxidation rate. The rate constants for loose contact soot oxidation in the presence of NO2......The influence of adding NO2 to 10 vol% O2/N2 on non-catalytic soot oxidation and soot oxidation in intimate or loose contact with a catalyst has been investigated. In non-catalytic soot oxidation the oxidation rate is increased significantly at lower temperatures by NO2. For soot oxidation in tight...... contact with a Co3O4 catalyst a more reactive NO2-containg atmosphere did not change the oxidation profile significantly during temperature programmed oxidation. This is consistent with the expected Mars van Krevelen mechanism, where the rate limiting step is reaction between carbon and lattice oxygen...

  5. Preparation of Molecular Sieve Catalyst and Application in the Catalytic Oxidation Treatment of Waste Water

    Institute of Scientific and Technical Information of China (English)

    WANG; RongMin

    2001-01-01

    Citric acid is an important additive in foods, cosmetics, medicine and so on, but it discharges about 10 ton of factory effluent when 1 ton of citric acid is produced. The COD of the factory effluent is near 20000 mg/L. The treatment of citric acid factory effluent is a serious problem in environmental chemistry.  It is found that molecular sieve support metal complexes have high catalytic activity in aerobic oxidation of alkene [1,2]. In this paper, a kind of molecular sieve catalyst was prepared. The catalyst was used for the treatment of citric acid factory effluent by method of catalytic oxygen oxidation.  ……

  6. Preparation and Catalytic Application of Novel Water Tolerant Solid Acid Catalysts of Zirconium Sulfate/HZSM-5

    Institute of Scientific and Technical Information of China (English)

    JIANG Ya-jie; JUAN Joon Ching; MENG Xiu-juan; CAO Wei-liang; YARMO Mohd Ambar; ZHANG Jing-chang

    2007-01-01

    Esterification of acrylic acid(AA) to produce AA esters has widespread application in the chemical industry. A series of water tolerant solid acid catalysts was prepared, and characterized by XRD, nitrogen adsorption, TGA-DTA, XPS, and ammonia adsorption FTIR. The effects of Si/Al ratio, zirconium sulfate(ZS) loading on HZSM-5 and calcination temperature on the esterification were investigated. When 20%(mass fraction) ZS is loaded on HZSM-5, the conversion of AA reaches 100%. XRD analysis indicates that ZS is highly dispersed on HZSM-5 because no crystalline structure assigned to ZS is found. Catalytic activity and hydrophobicity of ZS supported on HZSM-5 are higher compared with those of parent ZS or HZSM-5. Results show that this kind of novel catalysts is an efficient water tolerant solid acid catalyst for esterification reactions.

  7. Catalytic dechlorination of chlorobenzene in water by Pd/Fe bimetallic system

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hong-yi; XU Xin-hua; WANG Da-hui

    2003-01-01

    Catalytic reductive dechlorination of monochlorobenzene(MCB) was carried out in the palladium/iron system. With low Pd loading(0.005%), 45% dechlorination efficiency was achieved within 5 h Pd as catalyst accelerated the reductive dechlorination reaction. Dechlorination mechanism and kinetics were discussed. The reaction took place on the bimetal surface in a pseudo-first-order reaction, with the rate constant being 0.0071 min-1(KSA=8.0(10-3 L/(m2@h). The reduction product for MCB was benzene.

  8. Shape co-existence and structural evolution of the Vi13/2 band in 157Yb

    Institute of Scientific and Technical Information of China (English)

    郑勇; 周小红; 张玉虎; 郭应祥; 雷相国; 刘忠; 刘敏良; 罗万居; 温书贤; 竺礼华; 杨春祥

    2003-01-01

    The high-spin states of 157Yb have been studied via the reaction of 144Sm(16O, 3n) at 16O energy of 90 MeV using techniques of in-beam γ-ray spectroscopy. Measurement of γ-γ-t coincidences was performed with 11 BGO(AC)HPGe detectors. Based on the γ-γ coincidence relationships and the measured results of γ-ray anisotropies and DCO ratios, the level scheme for 157Yb was established. The shape co-existence and structural evolution of the Vi13/2 band with increasing angular momentum in 157Yb have been discussed. The systematics of the Vi13/2 bands in the N = 87 odd-A isotones have been compared.

  9. Effect of co-existing copper and calcium on the removal of As(V) by reused aluminum oxides.

    Science.gov (United States)

    Yang, J K; Park, Y J; Kim, K H; Lee, H Y; Min, K C; Lee, S M

    2013-01-01

    Among the various heavy metals, arsenic is frequently found in abandoned mine drainage and the environmental fate of arsenic in real aqueous solutions can be highly dependent on the presence of co-existing ions. In this study, removal of arsenate through adsorption on the reused aluminum oxide or through precipitation was investigated in a single and in a binary system as a function of pH and concentration. Different removal behaviors of arsenate were observed in the presence of different cations as well as a variation of the molar ratios of arsenate to cations. Co-operative effects on arsenate removal by precipitation in solution occurred with an increase of copper concentration, while a decrease of arsenate removal resulted in increasing calcium concentration. It was observed that the arsenate removal in the presence of calcium would be highly dependent on the molar ratios of both elements.

  10. An insight to conserved water molecular dynamics of catalytic and structural Zn(+2) ions in matrix metalloproteinase 13 of human.

    Science.gov (United States)

    Chakrabarti, Bornali; Bairagya, Hridoy R; Mallik, Payel; Mukhopadhyay, Bishnu P; Bera, Asim K

    2011-02-01

    Matrix Metalloproteinase (MMP)--13 or Collagenase--3 plays a significant role in the formation and remodeling of bone, tumor invasion and causes osteoarthritis. Water molecular dynamic studies of the five (1XUC, 1XUD, 1XUR, 456C, 830C) PDB and solvated structures of MMP-13 in human have been carried out upto 5 ns on assigning the differential charges (+2, +1, +0.5 e) to both the Zinc ions. The MM and MD-studies have revealed the coordination of three water molecules (W(H), W(I) and W(S)) to Zn(c) and one water to Zn(s). The transition of geometry around the Znc from tetrahedral to octahedral via trigonal bipyramidal, and for Zn(s) from tetrahedral to trigonal bipyramidal are seem interesting. Recognition of two zinc ions through water molecular bridging (Zn(c) - W(H) (W(1))...W(2)....W(3)....H(187) Zn(s)) and the stabilization of variable coordination geometries around metal ions may indicate the possible involvement of Zn(c) ...Zn(s) coupled mechanism in the catalytic process. So the hydrophilic topology and stereochemistry of water mediated coupling between Zn-ions may provide some plausible hope towards the design of some bidentate/polydentate bridging ligands or inhibitors for MMP-13.

  11. Study on Influence to Waste Water Treatment Plant’s Sludge by Low-carbon Catalytic Combustion Furnace of Natural Gas

    Directory of Open Access Journals (Sweden)

    Ren TianQi

    2016-01-01

    Full Text Available There are two parts in this experiment. One of is about the concentration of Variation of exhaust gas while heating sludge of waste water treatment plant. The other one is about introduce the problems of the traditional incineration processes of sludge of waste water treatment as compared between the sludge heated by natural gas catalytic combustion furnace and the tradition’s. We can see that natural gas low-carbon catalytic combustion furnace realize the near-zero emission of contaminates.

  12. Silver nanoparticles on amidoxime fibers for photo-catalytic degradation of organic dyes in waste water

    Science.gov (United States)

    Wu, Zhi-Chuan; Zhang, Yong; Tao, Ting-Xian; Zhang, Lifeng; Fong, Hao

    2010-11-01

    Herein we report that a new photo-catalyst of silver nanoparticles attached on the surface of amidoxime fibers was developed and evaluated. The nanoparticles had different sizes from tens to hundreds of nanometers and varied shapes of cube, plate, and sphere; and there were coordination interactions between the nanoparticles and the amidoxime fibers. The developed photo-catalyst demonstrated high activities for degradation of an organic dye of methyl orange, particularly under sunlight; and the catalyst could be re-activated for several times by simple tetrahydrofuran treatment. The results also suggested that the silver nanoparticles initiated and/or mediated the photo-oxidation reaction of methyl orange through localized surface plasmon resonance under sunlight, and the photo-catalytic activities were primarily determined by sizes and/or surface-to-mass ratios instead of shapes of the silver nanoparticles.

  13. Removal of volatile to semi-volatile organic contaminants from water using hollow fiber membrane contactors and catalytic destruction of the contaminants in the gas phase

    OpenAIRE

    Tarafder, Shamsul Abedin

    2007-01-01

    Abstract Chlorinated organic compounds and ether compounds are frequently found in groundwater and efficient treatment options are needed. In this study, the efficient transferal of the compounds from the water phase to the gas phase was studied followed by the catalytic treatment of the gas phase. For the removal of the organic contaminants from water, a microporous polypropylene hollow fiber membrane (HFM) module was operated under low strip gas flow to water flow ratios (_< 5:1). Rem...

  14. The perception of parents and teachers of the influence of yoga on the concentration and co-existing behaviour of learners with attention deficit hyperactivity disorder (ADHD)

    OpenAIRE

    Beart, K; Lessing, Ansie C

    2013-01-01

    This pilot study explores the perception of parents and teachers of the influence of yoga on the concentration and some co-existing behaviour of learners diagnosed with attention deficit hyperactivity disorder (ADHD). The researchers attended to impaired concentration as typical ADHD behaviour and further looked at co-existing phenomena such as aggression, anxiety, and a low self-esteem which the learners may manifest. Semi-structured interviews with parents, teachers and the l...

  15. Determination of Trace Amounts of Chromium(III) in Water Samples Using Online Flow Injection Catalytic Spectrophotometry

    Science.gov (United States)

    Zhao, Z. X.; Zhang, X. S.

    2017-01-01

    A new online flow injection spectrophotometric method for the determination of trivalent chromium was developed. This method is based on the property of trivalent chromium to be a catalyst for the oxidation of Indigo Carmine (IC) with potassium periodate and to lose its color in the presence of ethylenediaminetetraacetic acid and sodium tripolyphosphate. It was shown that Tween-20 serves as an additional accelerator of the catalytic oxidation. The linear dynamic range of the determination of Cr(III) was 1-40.0 μg/L, while the limit of detection was 0.05 μg/L. The correlation coefficient r was 0.998, while the relative standard deviation for 5 μg/L of the Cr(III) solution was 3.83%. The feasibility of this method was checked by its application to trivalent chromium determination in real water samples.

  16. The Mg2+-containing Water Cluster of Mammalian Cytochrome c Oxidase Collects Four Pumping Proton Equivalents in Each Catalytic Cycle.

    Science.gov (United States)

    Yano, Naomine; Muramoto, Kazumasa; Shimada, Atsuhiro; Takemura, Shuhei; Baba, Junpei; Fujisawa, Hidenori; Mochizuki, Masao; Shinzawa-Itoh, Kyoko; Yamashita, Eiki; Tsukihara, Tomitake; Yoshikawa, Shinya

    2016-11-11

    Bovine heart cytochrome c oxidase (CcO) pumps four proton equivalents per catalytic cycle through the H-pathway, a proton-conducting pathway, which includes a hydrogen bond network and a water channel operating in tandem. Protons are transferred by H3O(+) through the water channel from the N-side into the hydrogen bond network, where they are pumped to the P-side by electrostatic repulsion between protons and net positive charges created at heme a as a result of electron donation to O2 bound to heme a3 To block backward proton movement, the water channel remains closed after O2 binding until the sequential four-proton pumping process is complete. Thus, the hydrogen bond network must collect four proton equivalents before O2 binding. However, a region with the capacity to accept four proton equivalents was not discernable in the x-ray structures of the hydrogen bond network. The present x-ray structures of oxidized/reduced bovine CcO are improved from 1.8/1.9 to 1.5/1.6 Å resolution, increasing the structural information by 1.7/1.6 times and revealing that a large water cluster, which includes a Mg(2+) ion, is linked to the H-pathway. The cluster contains enough proton acceptor groups to retain four proton equivalents. The redox-coupled x-ray structural changes in Glu(198), which bridges the Mg(2+) and CuA (the initial electron acceptor from cytochrome c) sites, suggest that the CuA-Glu(198)-Mg(2+) system drives redox-coupled transfer of protons pooled in the water cluster to the H-pathway. Thus, these x-ray structures indicate that the Mg(2+)-containing water cluster is the crucial structural element providing the effective proton pumping in bovine CcO.

  17. Co-existence of PHF6 and NOTCH1 mutations in adult T-cell acute lymphoblastic leukemia.

    Science.gov (United States)

    Li, Min; Xiao, Lichan; Xu, Jingyan; Zhang, Run; Guo, Jingjing; Olson, Justin; Wu, Yujie; Li, Jianyong; Song, Chunhua; Ge, Zheng

    2016-07-01

    T-cell acute lymphoblastic leukemia (T-ALL) results from the collaboration of multiple genetic abnormalities in the transformation of T-cell progenitors. Plant homeodomain finger protein 6 (PHF6) has recently been established as a key tumor suppressor, which is mutated in T-ALL; however, the clinical significance of PHF6 mutations has not been fully determined in adult T-ALL. In the present study, amplification of the PHF6 exons was performed, followed by DNA sequencing to identify the genomic mutations and examine the expression of PHF6 in adult patients with T-ALL. The correlation between PHF6 mutations and clinical features was also analyzed using a χ(2) test, and between PHF6 mutations and survival curve using the Kaplan-Meier methods. PHF6 mutations were detected in 27.1% of the Chinese adults with T-ALL (16/59), 10 of which were found to be novel mutations. A significantly lower expression level of PHF6 was observed in T-ALL patients with PHF6 mutations compared with those without mutations. Of the observed mutations in PHF6, 6/16 were frame-shift mutations, indicating a PHF6 dysfunction in those patients. Of note, PHF6 mutations were found to be significantly associated with older age, lower hemoglobin levels, higher frequency of CD13 positivity and higher incidence of splenomegaly or lymphadenopathy. Furthermore, PHF6 mutations were found to be significantly correlated with Notch homolog 1, translocation-associated (Drosophila) (NOTCH1) mutations. The patients with T-ALL with co-existence of the two mutations had a significantly shorter event-free survival and a poor prognosis. The present results indicated that PHF6 is inactivated in adult T-ALL, due to its low expression and mutations. The present data indicated the synergistic effect of PHF6 and NOTCH1 mutations, as well as their co-existence, on the oncogenesis of adult T-ALL, and their potential as a prognostic marker for the disease.

  18. Tryptophanase from Escherichia coli: catalytic and spectral properties in water-organic solvents.

    Science.gov (United States)

    Faleev, N G; Dementieva, I S; Zakomirdina, L N; Gogoleva, O I; Belikov, V M

    1994-08-01

    In water-methanol and water-dimethylformamide (DMF) (1:1 v/v) solutions tryptophanase from E.coli retains its abilities to form a quinonoid complex with quasisubstrates and to catalyze the decomposition of S-o-nitrophenyl-L-cysteine (SOPC). Both the KM and Vmax values decrease in water-organic media. The affinities of tryptophanase for L-alanine, L-tryptophan, oxindolyl-L-alanine and indole in aqueous methanol are decreased, the effect being stronger for the more hydrophobic substances. In a water solution tryptophanase catalizes the reaction of SOPC with indole to form L-tryptophan while in water-organic solvents only decomposition of SOPC is observed.

  19. Heart Failure with Multi-organ Thrombosis: A Case of Antiphospholipid Syndrome Co-existing with Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Xueqi Li and Shipeng Wei

    2012-09-01

    Full Text Available Antiphospholipid Syndrome (APS is an autoimmune disease featured by venous or arterial thrombosis, fetal losses and thrombocytopenia in the presence of antiphospholipid antibodies. Here we reported one case of antiphospholipid syndrome together with dilated cardiomyopathy. A 46-year-old female patient complaining short of breath was found enlargement of atrial and ventricular compartments. The ecletrocardiogram and blood test revealed anteroseptal myocardial infarction, while no pulmonary thrombosis was present and therefore diagnosis of dilated cardiomyopathy was made. There were also thrombi formed in the cardial chambers and deep venous. During hospitalization, there was an onset of ischemic brain stroke and head MRI showed newly developed small infarctions. An elevation of anticardiolipin immunoglobulin A (ACAIGA was detected from the blood sample. The patient was discharged after being treated with anticoagulant, corticosteroid and other medicines for improving heart function. In our case, APS is the basic cause leading to multi-organ thrombosis and heart failure is mainly due to dilated cardiomyopathy, thus independent of APS. So this is the first time that cardiomyopathy co-existing with APS was reported.

  20. Co-existence of Echinococcus granulosus infection and cancer metastasis in the liver correlates with reduced Th1 immune responses.

    Science.gov (United States)

    Turhan, N; Esendagli, G; Ozkayar, O; Tunali, G; Sokmensuer, C; Abbasoglu, O

    2015-01-01

    A possible relationship between cancer and Echinococcus granulosus infection has been postulated. As T cells are critical players in immune responses against both infections and malignancies, in an experimental model of secondary echinococcosis and breast cancer, this study aims to observe the progression of cancer and to determine the characters of T-cell responses. 4T1 breast tumour cells were subcutaneously injected into mammary region, whereas protoscoleces were intraperitoneally inoculated into the mice. Hydatid cysts, tumours and metastases were determined with macroscopic and histopathological evaluation. T cells found in spleen, liver and tumour were characterised by flow cytometric analysis of CD3, CD4, CD8, CD25, CCR5, CCR3, IL-4 and IFN-γ. In the mice inoculated both with protoscoleces and with breast tumour cells, increased frequency of cancer metastasis was observed in the liver. The amount of CD4(+) T cells was increased in the liver and in the spleen of mice infected with E. granulosus. However, co-existence of echinococcosis and metastatic lesions in the liver was associated with significant reduction in the IFN-γ(+) and CCR5(+) Th1 cells and increase in the CD25(+) T cells. Our results may indicate an immunological link between cystic echinococcosis and cancer that allows tumour metastasis to flourish in the liver.

  1. Sjögren syndrome and neuromyelitis optica spectrum disorder co-exist in a common autoimmune milieu

    Directory of Open Access Journals (Sweden)

    Diogo C. Carvalho

    2014-06-01

    Full Text Available The relationship between Sjögren’s syndrome (SS and neuromyelitis optica spectrum disorder (NMOSD is not completely understood. We report two patients with both conditions and review 47 other previously reported cases meeting currently accepted diagnostic criteria, from 17 articles extracted from PubMed. Out of 44 patients whose gender was informed, 42 were females. Mean age at onset of neurological manifestation was 36.2 years (10-74. Serum anti-AQP4-IgG was positive in 32 patients, borderline in 1, and negative in 4. Our Case 1 was seronegative for AQP4-IgG and had no non-organ-specific autoantibodies other than anti-SSB antibodies. Our Case 2 had serum anti-AQP4, anti-SSA/SSB, anti-thyreoglobulin and anti-acethylcholine-receptor antibodies, as well as clinical hypothyreoidism, but no evidence of myasthenia gravis. Our Cases and others, as previously reported in literature, with similar heterogeneous autoimmune response to aquaporin-4, suggest that SS and NMO co-exist in a common autoimmune milieu which is not dependent on aquaporin-4 autoimmunity.

  2. Identification of intrinsic catalytic activity for electrochemical reduction of water molecules to generate hydrogen

    KAUST Repository

    Shinagawa, Tatsuya

    2015-01-01

    Insufficient hydronium ion activities at near-neutral pH and under unbuffered conditions induce diffusion-limited currents for hydrogen evolution, followed by a reaction with water molecules to generate hydrogen at elevated potentials. The observed constant current behaviors at near neutral pH reflect the intrinsic electrocatalytic reactivity of the metal electrodes for water reduction. This journal is © the Owner Societies.

  3. A new class of photo-catalytic materials and a novel principle for efficient water splitting under infrared and visible light - MgB2 as unexpected example

    CERN Document Server

    Kravets, V G

    2015-01-01

    Water splitting is unanimously recognized as environment friendly, potentially low cost and renewable energy solution based on the future hydrogen economy. Especially appealing is photo-catalytic water splitting whereby a suitably chosen catalyst dramatically improves efficiency of the hydrogen production driven by direct sunlight and allows it to happen even at zero driving potential. Here, we suggest a new class of stable photo-catalysts and the corresponding principle for catalytic water splitting in which infrared and visible light play the main role in producing the photocurrent and hydrogen. The new class of catalysts based on ionic binary metals with layered graphite-like structures which effectively absorb visible and infrared light facilitating the reaction of water splitting, suppress the inverse reaction of ion recombination by separating ions due to internal electric fields existing near alternating layers, provide the sites for ion trapping of both polarities, and finally deliver the electrons an...

  4. Ligand exchange and redox processes in iridium triazolylidene complexes relevant to catalytic water oxidation.

    Science.gov (United States)

    Petronilho, Ana; Llobet, Antoni; Albrecht, Martin

    2014-12-15

    Iridium(III) complexes containing a bidentate spectator ligand have emerged as powerful catalyst precursors for water oxidation. Here we investigate the initial steps of the transformation at the iridium center when using complex [IrCp*(pyr-trz)Cl] 1 (Cp* = pentamethylcyclopentadienyl, pyr-trz = 4-(2-pyridyl)-1,2,3-triazol-5-ylidene), a potent water oxidation catalyst precursor. Ligand exchange with water is facile and is reversed in the presence of chloride ions, while MeCN substitution is effective only from the corresponding aqua complex. A pKa of 8.3 for the aqua complex was determined, which is in agreement with strong electron donation from the triazolylidene ligand that is comparable to aryl anions. Evaluation of the pH-dependent oxidation process in aqueous media reveals two regimes (pH 4-8.5 and above pH 10.5) where proton-coupled electron transfer processes occur. These investigations will help to further optimize water oxidation catalysts and indicate that MeCN as a cosolvent has adverse effects for initiating water coordination in the oxidation process.

  5. Experimental studies on catalytic hydrogen recombiners for light water reactors; Experimentelle Untersuchungen zu katalytischen Wasserstoffkombinatoren fuer Leichtwasserreaktoren

    Energy Technology Data Exchange (ETDEWEB)

    Drinovac, P.

    2006-06-19

    In the course of core melt accidents in nuclear power plants a large amount of hydrogen can be produced and form an explosive or even detonative gas mixture with aerial oxygen in the reactor building. In the containment atmosphere of pressurized water reactors hydrogen combines a phlogistically with the oxygen present to form water vapor even at room temperature. In the past, experimental work conducted at various facilities has contributed little or nothing to an understanding of the operating principles of catalytic recombiners. Hence, the purpose of the present study was to conduct detailed investigations on a section of a recombiner essentially in order to deepen the understanding of reaction kinetics and heat transport processes. The results of the experiments presented in this dissertation form a large data base of measurements which provides an insight into the processes taking place in recombiners. The reaction-kinetic interpretation of the measured data confirms and deepens the diffusion theory - proposed in an earlier study. Thus it is now possible to validate detailed numeric models representing the processes in recombiners. Consequently the present study serves to broaden and corroborate competence in this significant area of reactor technology. In addition, the empirical knowledge thus gained may be used for a critical reassessment of previous numeric model calculations. (orig.)

  6. STUDY ON SYNTHESIS OF PVC SERIES OF MACROPOROUS SULFORIC RESINS AND THEIR APPLICATIONS IN CATALYTIC ESTERIFICATION AND WATER TREATMENT

    Institute of Scientific and Technical Information of China (English)

    LIYanfeng; FULiandi; 等

    1999-01-01

    The PVC serves of macroporous sulfonic cation-exchange resins were prepared by the sulfonation of a macroporous PVC bead with concentrated sulfonic acid or chlorosulfonic acid.the resulting sulfonic resin was employed in the investigation of catalytic esterification and solftening of water,The results show that the yields of esters reach 60.0-84.4% according as different fatty acids and alcohols,the refractive indexes of esters obtained resemble those reported in the references basically,meanwhile,345L softened water which holds ≤0.06mmol/L hardness would be prepared by 1 L wet sulfonic resin reusing for 4 times.The resulting sulfonic resins would have 1.6-2.0or 2.5-3.0mmol/g exchange capacity by using concentrated sulfonic acid or chlorosulfonic acid as sulfonating agent,respectively,The sulfonic resin has a macroporous structure taking the morphology with agglomerates of minutely spherical gel particles as characteristic.

  7. Catalytic activity of lignin peroxidase and partition of veratryl alcohol in AOT/isooctane/toluene/water reverse micelles.

    Science.gov (United States)

    Zhang, Wenjuan; Huang, Xirong; Li, Yuezhong; Qu, Yinbo; Gao, Peiji

    2006-04-01

    The activity of lignin peroxidase (LiP) and the partition of its optimum substrate veratryl alcohol (VA) in sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/isooctane/toluene/water reverse micelles were studied in this paper to understand the microheterogeneous effect of the medium on the catalytic properties of LiP hosted in the reverse micelle. Results showed that LiP from Phanerochaete chrysosporium could express its activity in the reverse micelles, but its activity depended, to a great extent, on the composition of the reverse micelles. Optimum activity occurred at a molar ratio of water to AOT (omega0) of 11, a pH value of 3.6, and a volume ratio of isooctane to toluene of 7-9. Under optimum conditions, the half-life of LiP was circa 12 h. The dependence of LiP activity on the volume fraction of water in the medium (theta), at a constant omega0 value of 11, indicated that VA was mainly solubilized in the pseudophase of the reverse micelle. Based on the pseudobiphasic model and the corresponding kinetic method, a linear line can be obtained in a plot of apparent Michaelis constant of VA vs theta, and the partition coefficient of VA between the pseudophase and the organic solvent phase was determined to be 35.8, which was higher than that (22.3) between bulk water and the corresponding mixed organic solvent. H2O2 inhibited LiP at concentrations higher than 80 microM; this concentration value seems to be different from that in aqueous solution (about 3 mM). The differences mentioned above should be ascribed to the microheterogeneity and the interface of the AOT reverse micelle.

  8. The catalytic efficiency of lipase in a novel water-in-[Bmim][PF6] microemulsion stabilized by both AOT and Triton X-100.

    Science.gov (United States)

    Xue, Luyan; Li, Ying; Zou, Feixue; Lu, Lu; Zhao, Yin; Huang, Xirong; Qu, Yinbo

    2012-04-01

    In the water-in-[Bmim][PF(6)] microemulsion stabilized by both AOT and Triton X-100, the lipase-catalyzed hydrolysis of 4-nitrophenyl butyrate (p-NPB) was investigated to evaluate the catalytic efficiency of lipase in this novel microemulsion. The structural parameters of the microemulsion and the conditions of the enzymatic reaction affect the catalytic activity of lipase, especially the concentration of Tris-HCl buffer. Under optimum conditions, the catalytic activity of lipase in the present microemulsion is much higher than that in H(2)O saturated [Bmim][PF(6)]. When the partitioning of the substrate in the microemulsion is taken into account, the catalytic efficiency of lipase in this novel microemulsion is 14.3 times that in H(2)O saturated [Bmim][PF(6)] due to the significant decrease of the Michaelis constant in the microemulsion. Due to the large interface, high water activity, and probably the activating effect of the imidazolium cation in the water pool, the present microemulsion is demonstrated to be a promising medium for the lipase-catalyzed hydrolytic reaction. To demonstrate an important biocatalytic application in the IL-based microemulsion, the lipase-catalyzed synthesis of the flavoring agent benzyl acetate via transesterification of vinyl acetate with benzyl alcohol was also studied in the medium. Due to the high dispersion of lipase, large interface and removal of the byproduct, a maximum yield of 94% was obtained, indicating that the novel microemulsion is really important and useful.

  9. Staphylococcus aureus SrrAB Affects Susceptibility to Hydrogen Peroxide and Co-Existence with Streptococcus sanguinis.

    Directory of Open Access Journals (Sweden)

    Yuichi Oogai

    Full Text Available Staphylococcus aureus is a pathogen and a commensal bacterial species that is found in humans. Bacterial two-component systems (TCSs sense and respond to environmental stresses, which include antimicrobial agents produced by other bacteria. In this study, we analyzed the relation between the TCS SrrAB and susceptibility to the hydrogen peroxide (H2O2 that is produced by Streptococcus sanguinis, which is a commensal oral streptococcus. An srrA-inactivated S. aureus mutant demonstrated low susceptibility to the H2O2 produced by S. sanguinis. We investigated the expression of anti-oxidant factors in the mutant. The expression of katA in the mutant was significantly higher than in the wild-type (WT in the presence or absence of 0.4 mM H2O2. The expression of dps in the mutant was significantly increased compared with the WT in the presence of H2O2 but not in the absence of H2O2. A katA or a dps-inactivated mutant had high susceptibility to H2O2 compared with WT. In addition, we found that the nitric oxide detoxification protein (flavohemoglobin: Hmp, which is regulated by SrrAB, was related to H2O2 susceptibility. The hmp-inactivated mutant had slightly lower susceptibility to the H2O2 produced by S. sanguinis than did WT. When a srrA-inactivated mutant or the WT were co-cultured with S. sanguinis, the population percentage of the mutant was significantly higher than the WT. In conclusion, SrrAB regulates katA, dps and hmp expression and affects H2O2 susceptibility. Our findings suggest that SrrAB is related in vivo to the co-existence of S. aureus with S. sanguinis.

  10. First-principles quantum mechanical investigations: Catalytic reactions of furfural on Pd(111) and at the water/Pd(111) interface

    Science.gov (United States)

    Xue, Wenhua

    Bio-oils have drawn more and more attention from scientists as a promising new clean, cheap energy source. One of the most interesting relevant issues is the effect of catalysts on the catalytic reactions that are used for producing bio-oils. Furfural, as a very important intermediate during these reactions, has attracted significant studies. However, the effect of catalysts, including particularly the liquid/solid interface formed by a metal catalyst and liquid water, in the catalytic reactions involving furfural still remains elusive. In this research, we performed ab initio molecular dynamics simulations and first-principles density-functional theory calculations to investigate the atomic-scale mechanisms of catalytic hydrogenation of furfural on the palladium surface and at the liquid/state interface formed by the palladium surface and liquid water. We studied all the possible mechanisms that lead to formation of furfuryl alcohol (FOL), formation of tetrahydrofurfural (THFAL), and formation of tetrahydrofurfurfuryl alcohol (THFOL). We found that liquid water plays a significant role in the hydrogenation reactions. During the reaction in the presence of water and the palladium catalyst, in particular, water directly participates in the hydrogenation of the aldehyde group of furfural and facilitates the formation of FOL by reducing the activation energy. Our calculations show that water provides hydrogen for the hydrogenation of the aldehyde group, and at the same time, a pre-existing hydrogen atom, which is resulted from dissociation of molecular hydrogen (experimentally, molecular hydrogen is always supplied for hydrogenation) on the palladium surface, is bonded to water, making the water molecule intact in structure. In the absence of water, on the other hand, formation of FOL and THFAL on the palladium surface involves almost the same energy barriers, suggesting a comparable selectivity. Overall, as water reduces the activation energy for the formation of FOL

  11. Gasificación catalítica de lodos de aguas residuales. // Catalytic gasification of residual waters muds.

    Directory of Open Access Journals (Sweden)

    L. M. García Rojas

    2005-05-01

    Full Text Available A partir de la necesidad de encontrar nuevas alternativas energéticas, se estudia en este trabajo la posibilidad de reducir agran escala la cantidad de alquitranes que acompaña al gas obtenido de la gasificación en lecho fluidizado de los lodos delas depuradoras de aguas residuales, este estudio conduce a una posible utilización de este gas en la generación deelectricidad, Para propiciar tal reducción se han empleado catalizadores secundarios reemplazando, en parte ocompletamente, la arena utilizada como agente fluidizante. Además la presencia de vapor de agua, que puede actuar comoreactante para el reformado de hidrocarburos, también puede ser beneficiosa a la hora de reducir la cantidad de alquitranesen el gas, por lo que, junto con la sustitución de la arena por un catalizador, se han realizado experimentos alimentandovapor de agua al reactor.Palabras claves: Gasificación, lecho fluidizado y lodos.____________________________________________________________________________Abstract.Starting from the necessity of finding new energy alternatives, it is presented in this paper the possibility to reduce in greatscale the quantity of tars that accompanies the gas obtained of the gasification in fluidized bed of muds in residual waters,this study leads to a possible use of this gas in the electricity generation, For propitiate such reduction a secondary catalystshas been used replacing, partly or completely, the sand used as fluidity agent. Also the presence of water steam that can actas reactant for the hydrocarbons reformed, it can also be beneficial when reducing the quantity of tars in the gas, for that,together with the substitution of sand for a catalyst, it have been carried out experiments feeding water steam to the reactor.Key words: Catalytic gasification, fluidity channel, muds.

  12. The effect of copper valence on catalytic combustion of styrene over the copper based catalysts in the absence and presence of water vapor☆

    Institute of Scientific and Technical Information of China (English)

    Hongyan Pan; Zhiyan He; Qian Lin; Fei Liu; Zhong Li

    2016-01-01

    Catalysts CuOx/γ-Al2O3-IH and CuOx/γ-Al2O3-IM were prepared, characterized, and tested for styrene combustion in the absence and presence of water vapor. The effect of copper valence of the catalysts on the catalytic activity for styrene combustion was discussed using the theory of hard soft acids and bases (HSAB). The results showed that the existence of water vapor in feed stream inhibited the catalytic activity for styrene combustion due to the competition adsorption of water molecule. HSAB theory confirmed that the local soft acidity of the catalyst CuOx/γ-Al2O3-IH was much stronger than that of the catalyst CuOx/γ-Al2O3-IM because of the higher content of soft acid Cu+on its surface, which increased the adsorption ability toward soft base of styrene and reduced the adsorption toward hard base of water vapor, and thus increased the catalytic activity for styrene combustion and weakened the negative influence of water vapor.

  13. Removal performance and mechanism of ibuprofen from water by catalytic ozonation using sludge-corncob activated carbon as catalyst.

    Science.gov (United States)

    Wang, Hongjuan; Zhang, Liqiu; Qi, Fei; Wang, Xue; Li, Lu; Feng, Li

    2014-09-01

    To discover the catalytic activity of sludge-corncob activated carbon in catalytic ozonation of Ibuprofen, the performance of sludge-corncob activated carbon and three selected commercial activated carbons as catalysts in catalytic ozonation was investigated. The observation indicates the degradation rate of Ibuprofen increases significantly in the presence of sludge-corncob activated carbon and the catalytic activity of sludge-corncob activated carbon is much higher than that of the other three commercial activated carbons. Ibuprofen's removal rate follows pseudo-first order kinetics model well. It is also found that the adsorption removal of Ibuprofen by sludge-corncob activated carbon is less than 30% after 40 min. And the removal efficiency of Ibuprofen in the hybrid ozone/sludge-corncob activated carbon system is higher than the sum of sludge-corncob activated carbon adsorption and ozonation alone, which is a supportive evidence for catalytic reaction. In addition, the results of radical scavenger experiments demonstrate that catalytic ozonation of Ibuprofen by sludge-corncob activated carbon follows a hydroxyl radical reaction pathway. During ozonation of Ibuprofen in the presence of activated carbon, ozone could be catalytically decomposed to form hydrogen peroxide, which can promote the formation of hydroxyl radical. The maximum amount of hydrogen peroxide occurs in the presence of sludge-corncob activated carbon, which can explain why sludge-corncob activated carbon has the best catalytic activity among four different activated carbons.

  14. Large scale analysis of co-existing post-translational modifications in histone tails reveals global fine structure of cross-talk

    DEFF Research Database (Denmark)

    Schwämmle, Veit; Aspalter, Claudia-Maria; Sidoli, Simone;

    2014-01-01

    Mass spectrometry (MS) is a powerful analytical method for the identification and quantification of co-existing post-translational modifications in histone proteins. One of the most important challenges in current chromatin biology is to characterize the relationships between co-existing histone...... sample-specific patterns for the co-frequency of histone post-translational modifications. We implemented a new method to identify positive and negative interplay between pairs of methylation and acetylation marks in proteins. Many of the detected features were conserved between different cell types...

  15. Preparation and characterization of a biochar from pistachio hull biomass and its catalytic potential for ozonation of water recalcitrant contaminants.

    Science.gov (United States)

    Moussavi, Gholamreza; Khosravi, Rasoul

    2012-09-01

    This work introduces a biochar as novel catalyst prepared from the pistachio hull, and demonstrates its catalytic potential for degrading the reactive red 198 (RR198) dye in catalytic ozonation processes (COPs). The prepared pistachio hull biochar (PHB) was a macroporous, basic material with low specific surface area. PHB had the greatest catalytic potential at an optimal alkaline pH of 10. Significant catalytic potential was observed when PHB was added to the ozonation reactor; a 58.4% catalytic potential was obtained in the decolorization of RR198 in the COP with 0.2g of catalyst after a reaction time of 60 min. A 71% mineralization (TOC reduction) of the dye solution was observed in the COP after a reaction time of 60 min. Overall, it can be concluded from the experimental results that the PHB is a promising and affordable catalyst for use in COPs for treatment of resistant organic compounds.

  16. Efficient catalytic interconversion between NADH and NAD+ accompanied by generation and consumption of hydrogen with a water-soluble iridium complex at ambient pressure and temperature.

    Science.gov (United States)

    Maenaka, Yuta; Suenobu, Tomoyoshi; Fukuzumi, Shunichi

    2012-01-11

    Regioselective hydrogenation of the oxidized form of β-nicotinamide adenine dinucleotide (NAD(+)) to the reduced form (NADH) with hydrogen (H(2)) has successfully been achieved in the presence of a catalytic amount of a [C,N] cyclometalated organoiridium complex [Ir(III)(Cp*)(4-(1H-pyrazol-1-yl-κN(2))benzoic acid-κC(3))(H(2)O)](2) SO(4) [1](2)·SO(4) under an atmospheric pressure of H(2) at room temperature in weakly basic water. The structure of the corresponding benzoate complex Ir(III)(Cp*)(4-(1H-pyrazol-1-yl-κN(2))-benzoate-κC(3))(H(2)O) 2 has been revealed by X-ray single-crystal structure analysis. The corresponding iridium hydride complex formed under an atmospheric pressure of H(2) undergoes the 1,4-selective hydrogenation of NAD(+) to form 1,4-NADH. On the other hand, in weakly acidic water the complex 1 was found to catalyze the hydrogen evolution from NADH to produce NAD(+) without photoirradiation at room temperature. NAD(+) exhibited an inhibitory behavior in both catalytic hydrogenation of NAD(+) with H(2) and H(2) evolution from NADH due to the binding of NAD(+) to the catalyst. The overall catalytic mechanism of interconversion between NADH and NAD(+) accompanied by generation and consumption of H(2) was revealed on the basis of the kinetic analysis and detection of the catalytic intermediates.

  17. Micro-channel catalytic reactor integration in CAPER and research/development on highly tritiated water handling and processing

    Energy Technology Data Exchange (ETDEWEB)

    Demange, D.; Cristescu, I.; Fanghaenel, E.; Gramlich, N.; Le, T.L.; Michling, R.; Moosmann, H.; Simon, K.H.; Wagner, R.; Welte, S. [Karlsruhe Institute of Technology, Institute for Technical Physics, Tritium Laboratory Karlsruhe, Eggenstein-Leopoldshafen (Germany); Glugla, M.; Shu, W.M.; Willms, R.S. [ITER Organization, Saint-Paul-lez-Durance (France)

    2015-03-15

    The CAPER facility of the Tritium Laboratory Karlsruhe has demonstrated the technology for the tokamak exhaust processing. CAPER has been significantly upgraded to pursue research/development programs towards highly tritiated water (HTW) handling and processing. The preliminary tests using a metal oxide reactor producing HTW afterward de-tritiated with PERMCAT were successful. In a later stage, a micro-channel catalytic reactor was installed in view of long term research program on HTW. The integration of this new system in CAPER was carried out along with a careful safety analysis due to high risk associated with such experiments. First experiments using the μ-CCR were performed trouble free, and HTW up to 360 kCi/kg was produced at a rate of 0.5 g/h. Such HTW was collected into a platinum zeolite bed (2 g of HTW for 20 g of Pt-zeolite), and in-situ detritiation was performed via isotopic exchange with deuterium. These first experimental results with tritium confirmed the potential for the capture and exchange method to be used for HTW in ITER. (authors)

  18. Solar Photo Catalytic Hydrogen Production from water using a dual bed photosystem

    Energy Technology Data Exchange (ETDEWEB)

    Florida Solar Energy Center

    2003-03-30

    A body of work was performed in which the feasibility of photocatalytically decomposing water into its constituent elements using a dual bed, or modular photosystem, under solar radiation was investigated. The system envisioned consists of two modules, each consisting of a shallow, flat, sealed container, in which microscopic photocatalytic particles are immobilized. The photocatalysts absorb light, generating free electrons and lattice vacancy holes, which are capable of performing reductive and oxidative chemistry, respectively. The photocatalysts would be chosen as to whether they specifically promote H{sub 2} or O{sub 2} evolution in their respective containers. An aqueous solution containing a redox mediator is pumped between the two chambers in order to transfer electron equivalents from one reaction to the other.

  19. The role of oxygen and water on molybdenum nanoclusters for electro catalytic ammonia production

    DEFF Research Database (Denmark)

    Howalt, Jakob Geelmuyden; Vegge, Tejs

    2014-01-01

    . In this study, we present theoretical investigations of the influence of oxygen adsorption and reduction on pure and nitrogen covered molybdenum nanocluster electro catalysts for electrochemical reduction of N2 to NH3 with the purpose of understanding oxygen and water poisoning of the catalyst. Density...... functional theory calculations are used in combination with the computational hydrogen electrode approach to calculate the free energy profile for electrochemical protonation of O and N2 species on cuboctahedral Mo13 nanoclusters. The calculations show that the molybdenum nanocluster will preferentially bind...... are -0.72 V or lower for all oxygen coverages studied, and it is thus possible to (re)activate (partially) oxidized nanoclusters for electrochemical ammonia production, e.g., using a dry proton conductor or an aqueous electrolyte. At lower oxygen coverages, nitrogen molecules can adsorb to the surface...

  20. A non-acid-assisted and non-hydroxyl-radical-related catalytic ozonation with ceria supported copper oxide in efficient oxalate degradation in water

    KAUST Repository

    Zhang, Tao

    2012-06-01

    Oxalate is usually used as a refractory model compound that cannot be effectively removed by ozone and hydroxyl radical oxidation in water. In this study, we found that ceria supported CuO significantly improved oxalate degradation in reaction with ozone. The optimum CuO loading amount was 12%. The molar ratio of oxalate removed/ozone consumption reached 0.84. The catalytic ozonation was most effective in a neutral pH range (6.7-7.9) and became ineffective when the water solution was acidic or alkaline. Moreover, bicarbonate, a ubiquitous hydroxyl radical scavenger in natural waters, significantly improved the catalytic degradation of oxalate. Therefore, the degradation relies on neither hydroxyl radical oxidation nor acid assistance, two pathways usually proposed for catalytic ozonation. These special characters of the catalyst make it suitable to be potentially used for practical degradation of refractory hydrophilic organic matter and compounds in water and wastewater. With in situ characterization, the new surface Cu(II) formed from ozone oxidation of the trace Cu(I) of the catalyst was found to be an active site in coordination with oxalate forming multi-dentate surface complex. It is proposed that the complex can be further oxidized by molecular ozone and then decomposes through intra-molecular electron transfer. The ceria support enhanced the activity of the surface Cu(I)/Cu(II) in this process. © 2012 Elsevier B.V.

  1. Simultaneous determination of dissolved inorganic chromium species in wastewater/natural waters by surfactant sensitized catalytic kinetic spectrophotometry

    Directory of Open Access Journals (Sweden)

    Ramazan Gürkan

    2017-02-01

    Full Text Available A simple, rapid, highly accurate and sensitive kinetic method is proposed for determining chromium(VI. The method is based on its catalytic effect on the oxidation of Celestine blue (CB+ by H2O2 in the presence of 2,2′-bipyridyl (Bipyr and cetylpyridinium chloride (CPC at pH 6.50. The reaction was monitored spectrophotometrically by measuring the absorbance of indicator dye at 645 nm. The analytical variables, which have influences on the sensitivity, were investigated and the optimum conditions were established. The optimized conditions made it possible to determine and speciate chromium in a linear range of 5–200 μg L−1 with a detection limit of 0.65 μg L−1. The recoveries and relative standard deviations (RSDs for the determination of 10, 25, 75 and 150 μg L−1 Cr(VI (n: 5 were in the range of 99.0–99.8% and 0.2–3.5%, respectively. The selectivity was also studied and greatly enhanced by adding a suitable masking mixture. The method was successfully applied to the simultaneous analysis of Cr(III and Cr(VI in natural water and waste water samples with a recovery changing in the range of 95–103% for Cr(III and 100–104% for Cr(VI. Its accuracy was validated by the analysis of certified reference materials with good agreement between certified and found values.

  2. Support effects and catalytic trends for water gas shift activity of transition metals

    DEFF Research Database (Denmark)

    Boisen, Astrid; Janssens, T.V.W.; Schumacher, Nana Maria Pii;

    2010-01-01

    CO and atomic oxygen on the metal; the latter is a good measure for the reactivity of the metal towards H2O. Generally, the activity of the catalysts with the Ce0.75Zr0.25O2 support is higher, compared to the corresponding MgAl2O4-supported catalysts. Exceptions are Cu and Au, which have a higher......Water gas shift activity measurements for 12 transition metals (Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Re, Ir, Pt, Au) supported on inert MgAl2O4 and Ce0.75Zr0.25O2 are presented, to elucidate the influence of the active metal and the support. The activity is related to the adsorption energy of molecular...... activity on the MgAl2O4 support and are both characterized by weak CO adsorption. For the MgAl2O4-supported catalysts a volcano-type relation between the activity and the adsorption energy of atomic oxygen on the metal is obtained. The maximum activity is found for metals with a binding energy of oxygen...

  3. Parental Choice of Schools and Parents' Perceptions of Multicultural and Co-Existence Education: The Case of the Israeli Palestinian-Jewish Bilingual Primary Schools

    Science.gov (United States)

    Bekerman, Zvi; Tatar, Moshe

    2009-01-01

    The present research effort aims to better understand parental choice of the Israeli Palestinian-Jewish bilingual primary schools and its implications in contributing (or not) to fostering multicultural and co-existence educational efforts in conflict-ridden societies. The manuscript offers a short description of the educational initiative under…

  4. On the co-existence of chemically peculiar Bp stars, slowly pulsating B stars and constant B stars in the same part of the H-R diagram

    NARCIS (Netherlands)

    Briquet, M.; Hubrig, S.; Cat, P. de; Aerts, C.; North, P.; Schöller, M.

    2007-01-01

    Aims. In order to better model massive B-type stars, we need to understand the physical processes taking place in slowly pulsating B (SPB) stars, chemically peculiar Bp stars, and non-pulsating normal B stars co-existing in the same part of the H-R diagram. Methods: We carry out a comparative study

  5. Governing the co-existence of GM crops : ex-ante regulation and ex-post liability under uncertainty and irreversibility

    NARCIS (Netherlands)

    Beckmann, V.; Soregaroli, C.; Wesseler, J.H.H.

    2006-01-01

    The future institutional environment for the co-existence of genetically modified (GM) crops, conventional crops and organic crops in Europe combines measures of ex-ante regulation and ex-post liability rules. Against this background we ask the following two questions: How does ex-ante regulation an

  6. Considerations for Managing Agricultural Co-Existence between Transgenic and Non-Transgenic Cultivars of Outcrossing Perennial Forage Plants in Dairy Pastures

    Directory of Open Access Journals (Sweden)

    Kevin F. Smith

    2016-11-01

    Full Text Available Many of the major forage species used in agriculture are outcrossing and rely on the exchange of pollen between individuals for reproduction; this includes the major species used for dairy production in grazing systems: perennial ryegrass (Lolium perenne L. and white clover (Trifolium repens L.. Cultivars of these species have been co-existing since contrasting cultivars were developed using plant breeding, but the consequences and need for strategies to manage co-existence have been made more prominent with the advent of genetic modification. Recent technological developments have seen the experimental evaluation of genetically modified (GM white clover and perennial ryegrass, although there is no current commercial growing of GM cultivars of these species. Co-existence frameworks already exist for two major cross-pollinated grain crops (canola and maize in Europe, and for alfalfa (Medicago sativa L. in the US, so many of the principles that the industry has developed for co-existence in these crops such as detection techniques, segregation, and agronomic management provide lessons and guidelines for outcrossing forage species, that are discussed in this paper.

  7. Negative catalytic effect of water on the reactivity of hydrogen abstraction from the C-H bond of dimethyl ether by deuterium atoms through tunneling at low temperatures

    Science.gov (United States)

    Oba, Yasuhiro; Watanabe, Naoki; Kouchi, Akira

    2016-10-01

    We report an experimental study on the catalytic effect of solid water on the reactivity of hydrogen abstraction (H-abstraction) from dimethyl ether (DME) in the low-temperature solid DME-H2O complex. When DME reacted with deuterium atoms on a surface at 15-25 K, it was efficiently deuterated via successive tunneling H-abstraction and deuterium (D)-addition reactions. The 'effective' rate constant for DME-H2O + D was found to be about 20 times smaller than that of pure DME + D. This provides the first evidence that the presence of solid water has a negative catalytic effect on tunneling H-abstraction reactions.

  8. The effect of preparation factors on the structural and catalytic properties of mesoporous nanocrystalline iron-based catalysts for high temperature water gas shift reaction

    Energy Technology Data Exchange (ETDEWEB)

    Meshkani, Fereshteh; Rezaei, Mehran [University of Kashan, Kashan (Iran, Islamic Republic of)

    2015-07-15

    A systematic study was done on the effect of preparation factors on the structural and catalytic properties of mesoporous nanocrystalline iron-based catalysts in high temperature water gas shift reaction. The catalysts were prepared by coprecipitation method, and the effect of the main preparation factors (pH, refluxing temperature, refluxing time, concentration of the precursors solution) was studied. The catalysts were characterized by powder X-ray diffraction (XRD), N{sub 2} adsorption (BET), Temperature programmed reduction (TPR), transmission and scanning electron microscopies (TEM, SEM) techniques. The results revealed that the preparation factors affected the textural and catalytic properties of the Fe-Cr-Cu catalyst. The results showed that the prepared catalyst with the highest activity showed higher specific surface area compared to commercial catalyst and consequently exhibited higher activity in high temperature water gas shift reaction. The TEM analysis showed a nanostructure for this sample with crystallite size less than 20 nm.

  9. Determination of Trace Vanadium(V)in Seawater and Fresh Water by the Catalytic Kinetic Spectrophotometric Method

    Institute of Scientific and Technical Information of China (English)

    JI Hongwei; SHA Yuanyuan; XIN Huizhen; LI Shuang

    2010-01-01

    A new kinetic spectrophotometric method has been developed for the determination of vanadium(V).The method is based on the catalytic effect of vanadium(V)on the oxidation of weak acid brilliant blue dye(RAWL)by KBrO3 using the citric acid as activation reagent.The obtained optimum conditions are:c(RAWL)= 1×10-4 molL-1,c(KBrO3)= 3×10-2 molL-1,c(citric acid)=9×10-3 molL-1,pH = 2.50,the reaction time being 7.0min and the temperature being 25.0℃.Under the optimum conditions,the proposed method allows the determination of vanadium(V)in the range of 0-70.0ng mL-1 and the detection limit is down to 0.407 ng mL-1.For standard vanadium(V)solution determination,the recovery efficiency is in the range of 98.5%-102% and the RSD ranges from 0.76%-1.25%.Moreover,it is demonstrated that most cations and anions do not interfere with the determination of vanadium(V)under the analytical condition.The new method was successfully applied in the determination of vanadium(V)in fresh water and seawater samples with satisfactory results.Vanadium(V)in the seawater samples from Qingdao offshore was determined using the method and the distribution of vanadium(V)was mapped.Compared with other instrumental analytical methods,the proposed method shows good selectivity,sensitivity,simplicity,lower cost and rapidity.It can be employed on shipboard easily.

  10. Effect of Mg/Al atom ratio of support on catalytic performance of Co-Mo/MgO-Al2O3 catalyst for water gas shift reaction

    Institute of Scientific and Technical Information of China (English)

    Yixin Lian; Huifang Wang; Quanxing Zheng; Weiping Fang; Yiquan Yang

    2009-01-01

    Co-Mo-based catalysts supported on mixed oxide supports MgO-Al2O3 with different Mg/Al atom ratios for water gas shift reaction were studied by means of TPR, Raman, XPS and ESR. It was found that the octahedral Mo species in oxidized Co-Mo/MgO(x)-Al2O3 catalyst and the contents of Mo5+, Mo4+, S2- and S2-2 species in the functioning catalysts increased with increasing the Mg/Al atom ratio of the support under the studied experimental conditions. This is favorable for the formation of the active Co-Mo-S phase of the catalysts. Catalytic performance testing results showed that the catalysts Co-Mo/MgO-Al2O3 with the Mg/Al atom ratio of the support in the range of 0.475-0.525 exhibited optimal catalytic activity for the reaction.

  11. Co-existence of phenylketonuria either with maple syrup urine disease or Sandhoff disease in two patients from Iran: emphasizing the role of consanguinity.

    Science.gov (United States)

    Abiri, Maryam; Talebi, Saeed; Uitto, Jouni; Youssefian, Leila; Vahidnezhad, Hassan; Shirzad, Tina; Salehpour, Shadab; Zeinali, Sirous

    2016-10-01

    Most inborn errors of metabolism (IEMs) are inherited in an autosomal recessive manner. IEMs are one of the major concerns in Iran due to its extensive consanguineous marriages. Herein, we report two patients with two co-existent IEMs: a girl affected by classic phenylketonuria (PKU) and maple syrup urine disease (MSUD) and a male patient affected with Sandhoff disease and PKU, where Sandhoff disease was suspected due to the presence of a cherry-red spot in the eyes at 6 months which is unrelated to PKU. Sequencing of candidate genes in the first patient revealed one novel and three recurrent compound heterozygous mutations of p.Ser231Pro and p.Ala300Ser in the PAH gene and p.Glu330Lys and p.Arg170Cys mutations in the BCKDHB gene. Genetic testing results in the second patient showed previously reported homozygous mutations of p.Arg261Gln in the PAH and p.Arg533Cys mutation in the HEXB gene. Genetic testing confirmed the clinical diagnosis of both diseases in both patients. To the best of our knowledge; this is the first report of the co-existence of two distinct genetic disorders in two individuals from Iran. Co-existent different IEMs in patients complicated the clinical diagnosis and management of the diseases.

  12. Increased frequency of co-existing JAK2 exon-12 or MPL exon-10 mutations in patients with low JAK2(V617F) allelic burden.

    Science.gov (United States)

    Nussenzveig, Roberto H; Pham, Ha T; Perkins, Sherrie L; Prchal, Josef T; Agarwal, Archana M; Salama, Mohamed E

    2016-01-01

    The frequency of co-existing JAK2(V617F)/MPL and JAK2(V617F)/JAK2 exon-12 mutations has not been previously investigated in MPNs. Poor survival was reported in primary myelofibrosis with low JAK2(V617F) allelic burden. However, mutational status of JAK2 exon-12 or MPL were not reported in these patients. This study developed a cost-effective multiplex high resolution melt assay that screens for mutations in JAK2 gene exons-12 and -14 ((V617F)) and MPL gene exon-10. Co-existing mutations with JAK2(V617F) were detected in 2.9% (6/208; two JAK2 exon-12 and four MPL exon-10) patient specimens with known JAK2(V617F) (allelic-burden range: 0.1-96.8%). Co-existing mutations were detected in specimens with < 12% JAK2(V617F) allelic burden. Current WHO guidelines do not recommend further testing once JAK2(V617F) mutation is detected in MPNs. The findings, however, indicate that quantification of JAK2(V617F) allele burden may be clinically relevant in MPNs and in those with low allelic burden additional testing for JAK2 exon-12 and MPL exon-10 mutation should be pursued.

  13. Spectroscopic, Electrochemical and Computational Characterisation of Ru Species Involved in Catalytic Water Oxidation: Evidence for a [RuV(O)(Py2Metacn)] Intermediate

    OpenAIRE

    Casadevall, Carla; Codolà Duch, Zoel; Costas Salgueiro, Miquel; Lloret Fillol, Julio

    2016-01-01

    A new family of ruthenium complexes based on the N-pentadentate ligand Py2Metacn (N-methyl-N′,N′′-bis(2-picolyl)-1,4,7-triazacyclononane) has been synthesised and its catalytic activity has been studied in the water-oxidation (WO) reaction. We have used chemical oxidants (ceric ammonium nitrate and NaIO4) to generate the WO intermediates [RuII(OH2)(Py2Metacn)]2+, [RuIII(OH2)(Py2Metacn)]3+, [RuIII(OH)(Py2Metacn)]2+ and [RuIV(O)(Py2Metacn)]2+, which have been characterised spectroscopically. Th...

  14. Occurrence and co-existence of localized musculoskeletal symptoms and findings in work-attending orchestra musicians - an exploratory cross-sectional study

    Directory of Open Access Journals (Sweden)

    Paarup Helene M

    2012-10-01

    Full Text Available Abstract Background Due to ergonomic exposure musicians are at risk of work-related musculoskeletal disorders in the neck, back, and upper extremities. The literature confirms musculoskeletal problems in these anatomic regions among orchestra musicians. Methods An explorative cross-sectional study among 441 musicians from six Danish symphony orchestras; 216 underwent a clinical examination constructed for the purpose. Prior to the examination the musicians rated their maximally perceived trouble within the last week on a scheme blinded to the examiner. Accessibility to the clinical examination differed between orchestras. The aims were to assess the prevalence of 1 perceived symptoms within the previous week in the neck, back and limbs and of 2 clinical findings in the neck, back, and upper extremities, and 3 to investigate the co-existence of the perceived symptoms and clinical findings. Results Symptoms and findings were most common in the neck, back, and shoulders. Due to a poor co-existence between self-reported symptoms and clinical findings musicians experiencing bodily trouble could not be identified through this clinical examination. Free accessibility to the examination was of major importance to participation. Conclusions In compliance with the purpose, perceived symptoms within the previous week and present clinical findings were assessed. Although both symptoms and findings were most frequent in the neck, back, and shoulders the co-existence of anatomically localized symptoms and findings was generally quite poor in this study. Discrepancy between symptoms and findings might be caused by the participants currently attending work and therefore being relatively healthy, and the fluctuating nature of musculoskeletal problems. Furthermore from a comparison of different measuring units - self-reported symptoms being period prevalence rates and clinical findings point prevalence rates; a bias which may also be inherent in similar studies

  15. Co-existent Paget’s Disease of the Bone, Prostate Carcinoma Skeletal Metastases and Fracture on Skeletal Scintigraphy-Lessons to be Learned

    Directory of Open Access Journals (Sweden)

    Luke I Sonoda

    2013-08-01

    Full Text Available Bone scintigraphy, despite being non-specific, is a very sensitive and simple investigation for patients with active Paget’s disease of the bone. Skeletal metastases and Paget’s disease may co-exist in the elderly patients as both conditions are commonly seen in this age group. Clinical and radiological correlation may help to improve the diagnostic specificity of a bone scintigram. We report a patient in whom concurrent Paget’s disease and a rib fracture became evident only on repeat scintigraphy following successful treatment of prostate carcinoma skeletal metastases.

  16. Co-existence of Endometriotic Cyst of the Ovary and Arias-Stella Reaction in a Non-Pregnant Woman: Report of a Rare Case.

    Science.gov (United States)

    Harikrishnan, Volga; Esaki, Muthuvel; Srinivasan, Chitra; Arockiasamy, Parimala; Ethirajan, Shanthi

    2016-03-01

    Endometriosis is defined as presence of endometrial tissue outside the uterus. It can occur anywhere in the ovary. In the ovary it is usually presented as cyst, termed as endometriotic cyst or Chocolate cyst. Arias-Stella reaction is usually seen in gestational endometrium or in ectopic gestation site and rarely in non-pregnant uterus with hormonal intake. Co-existence of endometriosis and Arias-Stella reaction is very rare. We present a very rare case of endometriotic cyst of the ovary exhibiting Arias -Stella reaction which was seen in of non pregnant patient without any history of hormonal intake.

  17. Mueller matrix analysis for all optical fiber co-existence of birefringence-polarization dependent gain-mode coupling at a single wavelength

    Institute of Scientific and Technical Information of China (English)

    Shang Chio; Wu Chong-Qing; Li Zheng-Yong; Yang Shuang-Shou; Gao Kai-Qiang; Yu Kuang-Lu; Feng Zhen

    2011-01-01

    Birefringence (polarization-related phase-shift),polarization dependent gain (PDG) and mode coupling are three factors that may synchronously influence the transmission of single-wavelength polarized light in optical fibers.This paper obtains a new Mueller matrix analysis,which can be used under conditions that all these three factors are existing and changing.According to our transmission model,the state of polarization (SOP) changes along an optical microstructure fiber with co-existence of birefringence-PDG-mode coupling were simulated. The simulated results,which show the phenomena of SOP constringency,are in good agreement with previous theoretical analyses.

  18. Engineered biochar from microwave-assisted catalytic pyrolysis of switchgrass for increasing water-holding capacity and fertility of sandy soil

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Badr A. [Department of Chemical and Biological Engineering, University of British Columbia, Vancouver BC V6T 1Z3 (Canada); Agricultural Engineering Department, Cairo University, Giza (Egypt); Ellis, Naoko [Department of Chemical and Biological Engineering, University of British Columbia, Vancouver BC V6T 1Z3 (Canada); Kim, Chang Soo [Department of Chemical and Biological Engineering, University of British Columbia, Vancouver BC V6T 1Z3 (Canada); Clean Energy Research Center, Korea Institute of Science and Technology, 14 gil 5 Hwarang-no Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Bi, Xiaotao, E-mail: tony.bi@ubc.ca [Department of Chemical and Biological Engineering, University of British Columbia, Vancouver BC V6T 1Z3 (Canada); Emam, Ahmed El-raie [Agricultural Engineering Department, Cairo University, Giza (Egypt)

    2016-10-01

    Engineered biochars produced from microwave-assisted catalytic pyrolysis of switchgrass have been evaluated in terms of their ability on improving water holding capacity (WHC), cation exchange capacity (CEC) and fertility of loamy sand soil. The addition of K{sub 3}PO{sub 4}, clinoptilolite and/or bentonite as catalysts during the pyrolysis process increased biochar surface area and plant nutrient contents. Adding biochar produced with 10 wt.% K{sub 3}PO{sub 4} + 10 wt.% clinoptilolite as catalysts to the soil at 2 wt% load increased soil WHC by 98% and 57% compared to the treatments without biochar (control) and with 10 wt.% clinoptilolite, respectively. Synergistic effects on increased soil WHC were manifested for biochars produced from combinations of two additives compared to single additive, which may be the result of increased biochar microporosity due to increased microwave heating rate. Biochar produced from microwave catalytic pyrolysis was more efficient in increasing the soil WHC due to its high porosity in comparison with the biochar produced from conventional pyrolysis at the same conditions. The increases in soil CEC varied widely compared to the control soil, ranging from 17 to 220% for the treatments with biochars produced with 10 wt% clinoptilolite at 400 °C, and 30 wt% K{sub 3}PO{sub 4} at 300 °C, respectively. Strong positive correlations also exist among soil WHC with CEC and biochar micropore area. Biochar from microwave-assisted catalytic pyrolysis appears to be a novel approach for producing biochar with high sorption affinity and high CEC. These catalysts remaining in the biochar product would provide essential nutrients for the growth of bioenergy and food crops. - Highlights: • High quality biochar was made by catalytic pyrolysis in a microwave reactor. • High heating rate and good biochar quality were achieved using K{sub 3}PO{sub 4} and clinoptilolite mixture. • Biochars showed significant increase in soil WHC and CEC.

  19. Fiber mediated receptor masking in non-infected bystander cells restricts adenovirus cell killing effect but promotes adenovirus host co-existence.

    Directory of Open Access Journals (Sweden)

    Johan Rebetz

    Full Text Available The basic concept of conditionally replicating adenoviruses (CRAD as oncolytic agents is that progenies generated from each round of infection will disperse, infect and kill new cancer cells. However, CRAD has only inhibited, but not eradicated tumor growth in xenograft tumor therapy, and CRAD therapy has had only marginal clinical benefit to cancer patients. Here, we found that CRAD propagation and cancer cell survival co-existed for long periods of time when infection was initiated at low multiplicity of infection (MOI, and cancer cell killing was inefficient and slow compared to the assumed cell killing effect upon infection at high MOI. Excessive production of fiber molecules from initial CRAD infection of only 1 to 2% cancer cells and their release prior to the viral particle itself caused a tropism-specific receptor masking in both infected and non-infected bystander cells. Consequently, the non-infected bystander cells were inefficiently bound and infected by CRAD progenies. Further, fiber overproduction with concomitant restriction of adenovirus spread was observed in xenograft cancer therapy models. Besides the CAR-binding Ad4, Ad5, and Ad37, infection with CD46-binding Ad35 and Ad11 also caused receptor masking. Fiber overproduction and its resulting receptor masking thus play a key role in limiting CRAD functionality, but potentially promote adenovirus and host cell co-existence. These findings also give important clues for understanding mechanisms underlying the natural infection course of various adenoviruses.

  20. Association of Co-Existing Impairments in Cognition and Self-Rated Vision and Hearing With Health Outcomes in Older Adults

    Directory of Open Access Journals (Sweden)

    Phillip L. Liu MD, MBA

    2016-01-01

    Full Text Available Objective: The objective of this study was to assess the relationship of disability (activities of daily living [ADL] and instrumental ADL [IADL], self-rated health (SRH, and 6-year mortality with co-existing impairments in vision (self-rated, hearing (self-rated, and/or cognition (Short Portable Mental Status Questionnaire in older adults. Method: The study sample comprised of 3,871 participants from the North Carolina Established Populations for Epidemiologic Studies of the Elderly study (NC EPESE. Results: Persons with all three impairments had increased odds of ADL/IADL disability and low SRH. Participants with combined visual and cognitive impairments had increased odds of mortality. Whereas sensory impairments were associated with poor SRH, cognitive impairment was not unless both sensory impairments were present. Conclusion: Co-existent sensory and cognitive impairments were associated with higher risk of impaired functional status. Self-rated auditory impairment alone was not associated with higher odds of death, but mortality was linked to visual and, particularly, cognitive impairment, alone or combined.

  1. Resolution of Ibuprofen Ester by Catalytic Antibodies in Water-miscible Organic-solvents%水-有机溶剂混溶体系中催化抗体催化拆分布洛芳脂

    Institute of Scientific and Technical Information of China (English)

    杨根生; 应黎; 欧志敏; 姚善泾

    2009-01-01

    The asymmetric hydrolysis of racemic ibuprofen ester is one of the most important methods for chiral separation of ibuprofen. In this work, a catalytic antibody that accelerates the rate of enantioselective hydrolysis of ibuprofen methyl ester was obtained against an immunogen consisting of tetrahedral phosphonatc hapten attached to bovine serum albumin (BSA). The catalytic activity of the catalytic antibody in the water-miscible organic-solvent system composed of a buffer solution and TV, .N-dimethylformamide (DMF) was studied. With 6% DMF in the buffer solution (containing catalytic antibody 0.25 umol, 0.2 mol·L-1 phosphate buffer, pH 8) at 37℃ for 10 h, a good conversion (48.7%) and high cnantiomeric excess (>99%) could be reached. The kinetic analysis of the cata-lytic antibody-catalyzed reaction showed that the hydrolysis in the water-miscible organic-solvent system with DMF in buffer solution followed the Michaelis-Menten kinetics. The catalytic efficiency (kcat/km) was enhanced to 151.91 L·mmol-1·min-1, twice as large as that for the buffer solution only.

  2. Engineered biochar from microwave-assisted catalytic pyrolysis of switchgrass for increasing water-holding capacity and fertility of sandy soil.

    Science.gov (United States)

    Mohamed, Badr A; Ellis, Naoko; Kim, Chang Soo; Bi, Xiaotao; Emam, Ahmed El-Raie

    2016-10-01

    Engineered biochars produced from microwave-assisted catalytic pyrolysis of switchgrass have been evaluated in terms of their ability on improving water holding capacity (WHC), cation exchange capacity (CEC) and fertility of loamy sand soil. The addition of K3PO4, clinoptilolite and/or bentonite as catalysts during the pyrolysis process increased biochar surface area and plant nutrient contents. Adding biochar produced with 10wt.% K3PO4+10 wt.% clinoptilolite as catalysts to the soil at 2wt% load increased soil WHC by 98% and 57% compared to the treatments without biochar (control) and with 10wt.% clinoptilolite, respectively. Synergistic effects on increased soil WHC were manifested for biochars produced from combinations of two additives compared to single additive, which may be the result of increased biochar microporosity due to increased microwave heating rate. Biochar produced from microwave catalytic pyrolysis was more efficient in increasing the soil WHC due to its high porosity in comparison with the biochar produced from conventional pyrolysis at the same conditions. The increases in soil CEC varied widely compared to the control soil, ranging from 17 to 220% for the treatments with biochars produced with 10wt% clinoptilolite at 400°C, and 30wt% K3PO4 at 300°C, respectively. Strong positive correlations also exist among soil WHC with CEC and biochar micropore area. Biochar from microwave-assisted catalytic pyrolysis appears to be a novel approach for producing biochar with high sorption affinity and high CEC. These catalysts remaining in the biochar product would provide essential nutrients for the growth of bioenergy and food crops.

  3. Removal of Mn{sup 2+} from water by 'aged' biofilter media: The role of catalytic oxides layers

    Energy Technology Data Exchange (ETDEWEB)

    Sahabi, D.M.; Takeda, M.; Suzuki, I.; Koizurni, J. [Yokohama National University, Kanagawa (Japan). Dept. of Chemical & Energy Engineering

    2009-02-15

    The present work was aimed at evaluating the surface coatings characteristics and autocatalytic manganese oxidation potentials of two groups of 'aged' biofilter media. This refers to the anthracite filter media of a biological water treatment plant on which metal oxides and a biofilm have deposited on the surface of the filter media over long time of filtration. Duplicate samples of anthracite filter media were collected from each of the six filter wells in the plant and classified into two groups, based on their duration of operation, as 3-years filter media and 15-years filter media. Batch experiments showed that the 15-years filter media exhibited very high manganese sorption capacity and were less dependent on the microbial activity than the 3-years filter media. Results of the surface coatings analyses indicated that the biofilter materials is predominantly composed of variable layers of manganese and iron oxides, with microbial biomass contributing only about 3.5 and 1.4% of the dry weight of the surface coatings on the 3- and 15-years filter media respectively. Investigations onto the Mn{sup 2+} sorption by the lyophilized biofilter media showed that, the sorption kinetics on the catalytic oxides layers followed the pseudo-second-order kinetics model, thus suggesting chemisorption as the dominant mechanism of Mn{sup 2+} removal. This implied that manganese removal by these biofilters is mainly by adsorption of Mn{sup 2+} onto the iron and manganese (catalytic) oxides layers and autocatalytic oxidation. The present study has clearly linked MN{sub 2}+ oxidation to the catalytic oxides layers on the aged biofilter media.

  4. Welfare and Co-existence

    NARCIS (Netherlands)

    Zilberman, David; Wesseler, J.H.H.

    2016-01-01

    The backlash against the introduction of genetically modified (GM) crops and the concern about contamination of non-GM crops by genetic material originating from GM crops has resulted in a complex and costly legal and physical arrangement for coexistence of GM and non-GM agricultural product systems

  5. Application of sludge-based carbonaceous materials in a hybrid water treatment process based on adsorption and catalytic wet air oxidation.

    Science.gov (United States)

    Julcour Lebigue, Carine; Andriantsiferana, Caroline; N'Guessan Krou; Ayral, Catherine; Mohamed, Elham; Wilhelm, Anne-Marie; Delmas, Henri; Le Coq, Laurence; Gerente, Claire; Smith, Karl M; Pullket, Suangusa; Fowler, Geoffrey D; Graham, Nigel J D

    2010-12-01

    This paper describes a preliminary evaluation of the performance of carbonaceous materials prepared from sewage sludges (SBCMs) in a hybrid water treatment process based on adsorption and catalytic wet air oxidation; phenol was used as the model pollutant. Three different sewage sludges were treated by either carbonisation or steam activation, and the physico-chemical properties of the resultant carbonaceous materials (e.g. hardness, BET surface area, ash and elemental content, surface chemistry) were evaluated and compared with a commercial reference activated carbon (PICA F22). The adsorption capacity for phenol of the SBCMs was greater than suggested by their BET surface area, but less than F22; a steam activated, dewatered raw sludge (SA_DRAW) had the greatest adsorption capacity of the SBCMs in the investigated range of concentrations (oxidation tests, the SBCMs demonstrated catalytic behaviour arising from their substrate adsorptivity and metal content. Recycling of SA_DRAW in successive oxidations led to significant structural attrition and a hardened SA_DRAW was evaluated, but found to be unsatisfactory during the oxidation step. In a combined adsorption-oxidation sequence, both the PICA carbon and a selected SBCM showed deterioration in phenol adsorption after oxidative regeneration, but a steady state performance was reached after 2 or 3 cycles.

  6. Ce(IV)- and light-driven water oxidation by [Ru(terpy)(pic)3]2+ analogues: catalytic and mechanistic studies.

    Science.gov (United States)

    Duan, Lele; Xu, Yunhua; Tong, Lianpeng; Sun, Licheng

    2011-02-18

    A series of mononuclear ruthenium polypyridyl complexes [Ru(Mebimpy)(pic)(3)](PF(6))(2) (2; Mebimpy = 2,6-bis(1-methylbenzimidazol-2-yl)pyridine; pic = 4-picoline), Ru(bimpy)(pic)(3) (3; H(2)bimpy = 2,6-bis(benzimidazol-2-yl)pyridine), trans-[Ru(terpy)(pic)(2)Cl](PF(6)) (4; terpy = 2,2';6',2"-terpyridine), and trans-[Ru(terpy)(pic)(2)(OH(2))](ClO(4))(2) (5) are synthesized and characterized as analogues of the known Ru complex, [Ru(terpy)(pic)(3)](PF(6))(2) (1). The effect of the ligands on electronic and catalytic properties is studied and discussed. The negatively charged ligand, bimpy(2-), has a remarkable influence on the electrochemical events due to its strong electron-donating ability. The performance in light- and Ce(IV)-driven (Ce(IV) = Ce(NH(4))(2)(NO(3))(6)) water oxidation is successfully demonstrated. We propose that ligand exchange between pic and H(2)O occurs to form the real catalyst, a Ru-aqua complex. The synthesis and testing of trans-[Ru(terpy)(pic)(2)(OH(2))](ClO(4))(2) (5) confirmed our proposal. In addition, complex 5 possesses the best catalytic activity among these five complexes.

  7. Isotropic-Cholesteric Co-Existence and Magnetic Field-Induced Isotropic-Nematic Transition of Filamentous Bacteriophage FD in Aqueous Suspension.

    Science.gov (United States)

    Tang, Jianxin

    1995-01-01

    Isotropic to liquid crystalline phase transition for a lyotropic suspension of geometrically asymmetric macromolecules occurs to a wild class of synthetic polymers and biopolymers. Although in decades statistical mechanical theories have been developed to predict the thermodynamic conditions and the properties of such transition, quantitative comparison with theory has been compounded with complications such as charge, shape, polydispersity in size, and additional interactions with the solvent and among the macromolecules themselves. We chose the aqueous suspension of the filamentous bacteriophage fd as a model system to study the isotropic to liquid crystalline transition. The co-existence concentrations, as a function of ionic strength, were measured directly by spectrophotometry. Our data confirm quantitatively the predictions of a statistical mechanic treatment first described by Onsager, modified to include the effects of charge and flexibility of rodlike particles. We have also extended a previous study of the pretransitional angular correlations in the isotropic solutions of fd through the measurement of the magnetic-field-induced birefringence, i.e. the measurement of the Cotton-Mouton constant. At several ionic strengths the magnetic-field-induced birefringence, which is proportional to the number of particles in a correlation volume N_{rm corr}, was measured for fd concentrations spanning the entire isotropic region. From this data the limiting concentration of stability (spinodal) of the isotropic phase is obtained. A theoretical expression for the magnetic birefringence of persistent polymers was derived and agreed well with the data with the exception that N_{rm corr} at the isotropic to liquid crystal transition was smaller than predicted. In the proximity of the highest possible isotropic concentration, that is the isotropic in co-existence with anisotropic, we studied the effect of a high magnetic field. A first order field-induced isotropic

  8. Influence of co-existing atrial fibrillation on the efficacy of atorvastatin treatment in patients with dilated cardiomyopathy: a pilot study

    Directory of Open Access Journals (Sweden)

    Desai Ravi

    2010-02-01

    Full Text Available Abstract Introduction The aim of the study was to assess the influence of co-existing atrial fibrillation (AF on inflammatory condition factors, left ventricular function, clinical course and the efficacy of statin treatment of congestive heart failure in the course of dilated cardiomyopathy (DCM. Material and methods In a prospective, randomized, open-label study, 69 patients with DCM and left ventricular ejection fraction (LVEF ≤40% were divided into two groups, with and without AF, who were treated according to the recommended standards. 68% of patients from the group with AF and 59% of patients from the group without AF were administered atorvastatin 40 mg daily for 8 weeks and 10 mg for next 4 months. Clinical examination with the assessment of body mass index (BMI and waist size were followed by routine laboratory tests, measurement of concentration of tumor necrosis factor (TNF-α, interleukin-6 (IL-6, and IL-10 in blood plasma, N-terminal pro-brain natriuretic peptide (NT-proBNP concentration in blood serum, echocardiographic examination, and the assessment of exercise capacity in 6-minute walk test (6-MWT. After six months, morbidity rate and the number of heart failure hospitalizations were also observed. Results In the whole population of patients, a significantly higher concentration of NT-proBNP was observed in the AF group (2669 ± 2192 vs 1540 ± 1067, p = 0.02. After statin treatment, in patients with DCM and co-existing AF, higher values of NT-proBNP and IL-6 were observed compared to non-AF patients (1530 ± 1054 vs 1006 ± 1195, p = 0.04 and (14.16 ± 13.40 vs 6.74 ± 5.45, p = 0.02, respectively. Conclusion In patients with DCM and co-existing AF, a weaker effect of atorvastatin concerning the reduction of IL-6 and NT-proBNP concentration was observed than in patients without atrial fibrillation. Trials Registration (ClinialTrial.gov No.: NCT01015144

  9. Catalytic Kinetic Determination of Micro Amounts of Oxalic Acid by Second-Order Derivative Oscillopolarography

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    It was found that micro amounts of oxalate showed a very strong catalytic effect on the slow reaction between K2Cr2O7 and Orange Ⅳ in a diluted sulfuric acid medium in a water bath at 70 ℃. Orange Ⅳ exhibited a sensitive second-order derivative polarographic wave at -0.50 V(vs. SCE). This provides the basis for a sensitive and selective catalytic kinetic method for oxalate determination with second-order derivative oscillopolarography. The effects of sulphuric acid, K2Cr2O7, and orange Ⅳ concentrations, reaction temperature and reaction time were investigated. A calibration curve of oxalate in the range of 0.1—2.0 μg/mL was obtained by the fixed-time procedure. The detection limit was 0.03 μg/ mL. The possible interference from co-existing substances or ions was examined. The new method has a high sensitivity and a good selectivity compared to other existing methods for oxalic acid determination. It has been applied to the determination of micro amounts of oxalate in real urine samples with satisfactory results.

  10. Adsorption and bio-sorption of nickel ions and reuse for 2-chlorophenol catalytic ozonation oxidation degradation from water

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Wei, E-mail: chmawv@yahoo.com [School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Zong, Panpan; Cheng, Zihong [School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Wang, Baodong; Sun, Qi [National Institute of Clean-and-low Carbon Energy, Beijing 102209 (China)

    2014-02-15

    Highlights: • Biomass and fly ash which were widespread for adsorption of heavy metal ions. • Preparation of catalyst by saturated adsorbents for 2-chlorophenol ozone degradation. • This work demonstrated that the O{sub 3}/catalyst process was an effective pathway. • The use of nickel ions, fly ash and sawdust to achieve the recycling utilization of resources. -- Abstract: This work explored the preparation of an effective and low-cost catalyst and investigated its catalytic capacity for 2-chlorophenol ozonation oxidation degradation in wastewater by using an ozone oxidation batch reactor. The catalyst was directly prepared by the reuse of fly ash and sawdust after saturated adsorption of nickel ions from wastewater, which was proposed as an efficient and economic approach. The obtained catalyst was characterized by TGA, BET, FTIR, XRD, and SEM, the results showed that fly ash as the basic framework has high specific surface area and the addition of sawdust as the porogen agent could improve the pore structure of the catalyst. The adsorption of nickel ions by fly ash and sawdust from aqueous solution was also investigated in this study. The results obtained from the experiments indicated that adsorption of nickel ions by fly ash and biomass sawdust could be well described by Langmuir isotherm model and pseudo second order kinetic model. The catalytic performance of catalyst was studied in terms of the effect of time, liquid–solid ratio and pH on 2-chlorophenol ozonation degradation. It was found that the catalyst could effectively improve the ozonation reaction rate at pH = 7 with a 2:1 liquid–solid ratio. The kinetic study demonstrated that the reaction followed the first order model, and the rate constant increased 267% (0.03–0.1 min{sup −1}) of 2-chlorophenol ozonation degradation with 5 mmol/L concentration at pH = 7.0 compared with ozonation alone.

  11. Adsorption and bio-sorption of nickel ions and reuse for 2-chlorophenol catalytic ozonation oxidation degradation from water.

    Science.gov (United States)

    Ma, Wei; Zong, Panpan; Cheng, Zihong; Wang, Baodong; Sun, Qi

    2014-02-15

    This work explored the preparation of an effective and low-cost catalyst and investigated its catalytic capacity for 2-chlorophenol ozonation oxidation degradation in wastewater by using an ozone oxidation batch reactor. The catalyst was directly prepared by the reuse of fly ash and sawdust after saturated adsorption of nickel ions from wastewater, which was proposed as an efficient and economic approach. The obtained catalyst was characterized by TGA, BET, FTIR, XRD, and SEM, the results showed that fly ash as the basic framework has high specific surface area and the addition of sawdust as the porogen agent could improve the pore structure of the catalyst. The adsorption of nickel ions by fly ash and sawdust from aqueous solution was also investigated in this study. The results obtained from the experiments indicated that adsorption of nickel ions by fly ash and biomass sawdust could be well described by Langmuir isotherm model and pseudo second order kinetic model. The catalytic performance of catalyst was studied in terms of the effect of time, liquid-solid ratio and pH on 2-chlorophenol ozonation degradation. It was found that the catalyst could effectively improve the ozonation reaction rate at pH=7 with a 2:1 liquid-solid ratio. The kinetic study demonstrated that the reaction followed the first order model, and the rate constant increased 267% (0.03-0.1 min(-1)) of 2-chlorophenol ozonation degradation with 5 mmol/L concentration at pH=7.0 compared with ozonation alone.

  12. Experimental research on catalysts and their catalytic mechanism for hydrogen production by gasification of peanut shell in supercritical water

    Institute of Scientific and Technical Information of China (English)

    PEI Aixia; GUO Liejin; JIN Hui

    2007-01-01

    Peanut shell,mixed with sodium carboxymethylcellulose,was gasified at a temperature of 450℃ and a pressure range from 24 to 27 MPa with the presence of different catalysts,including K2CO3,ZnCl2 and Raney-Ni.The experimental results show that different catalysts have greatly different effects on the reaction.Gasification efficiency (GE),hydrogen gasification efficiency (GHE),carbon gasification efficiency (GCE),yield of hydrogen production (YH2) and potential yield of hydrogen production (YPH2) are applied to describe the catalytic efficiency.From the result of gaseous components,ZnCl2 has the highest hydrogen selectivity,K2CO3 is lower,and Raney-Ni is the lowest,but Raney-Ni is the most favorable to gasify biomass among the three catalysts,and its GE,GHE,GcE reach 126.84%,185.71%,94.24%,respectively.As expected,hydrogen selectivity increased and CH4 reduced rapidly when the mixture of ZnCl2 and Raney-Ni is used under the same condition.The optimization mixture appeared when 0.2 g of ZnCl2 was added to 1 g of Raney-Ni,43.56 g·kg-1 of hydrogen production was obtained.In addition,the catalytic mechanisms of different catalysts were analyzed,and the possible reaction pathway was brought forward,which helped to explain the experiment phenomena and results correctly.

  13. Influence of co-existed benzo[a]pyrene and copper on the cellular characteristics of Stenotrophomonas maltophilia during biodegradation and transformation.

    Science.gov (United States)

    Chen, Shuona; Yin, Hua; Ye, Jinshao; Peng, Hui; Liu, Zehua; Dang, Zhi; Chang, Jingjing

    2014-04-01

    Microbial remediation has been proposed as a promising technique to remove pollutions, however, its application has been hindered by the lack of understanding the mechanisms involved in contaminants conversion and the influence of pollutants on cellular characteristics. To address this problem, biodegradation and transformation of BaP-Cu(II) by Stenotrophomonas maltophilia, along with interactions of these pollutants with microbial cells through FCM assay were investigated. The results indicated that BaP and Cu(II) were rapidly removed by S. maltophilia on the 1st d, but only less than 10% BaP was broken down due to temporary store in cells, instead of being decomposed immediately. The key ATP enzymes in cells were then activated by BaP to promote bacteria to further decompose BaP. Stimulation of co-existed contaminants strengthened cell membrane permeability and altered cell structure, but a higher esterase activity and DNA in cells of S. maltophilia were still retained.

  14. Co-existence of clonal expanded autologous and transplacental-acquired maternal T cells in recombination activating gene-deficient severe combined immunodeficiency

    Science.gov (United States)

    Lev, A; Simon, A J; Ben-Ari, J; Takagi, D; Stauber, T; Trakhtenbrot, L; Rosenthal, E; Rechavi, G; Amariglio, N; Somech, R

    2014-01-01

    It is commonly accepted that the presence of high amounts of maternal T cells excludes Omenn syndrome (OS) in severe combined immunodeficiency (SCID). We report a SCID patient with a novel mutation in the recombination activating gene (RAG)1 gene (4-BP DEL.1406 TTGC) who presented with immunodeficiency and OS. Several assays, including representatives of specific T cell receptors (TCR), Vβ families and TCR-γ rearrangements, were performed in order to understand more clearly the nature and origin of the patient's T cells. The patient had oligoclonal T cells which, based on the patient–mother human leucocyte antigen (HLA)-B50 mismatch, were either autologous or of maternal origin. These cell populations were different in their numbers of regulatory T cells (Treg) and the diversity of TCR repertoires. This is the first description of the co-existence of large amounts of clonal expanded autologous and transplacental-acquired maternal T cells in RAG1-deficient SCID. PMID:24666246

  15. A Mi’kmaw Perspective on Advancing Salmon Governance in Nova Scotia, Canada: Setting the Stage for Collaborative Co-Existence

    Directory of Open Access Journals (Sweden)

    Shelley K. Denny

    2016-09-01

    Full Text Available Issues related to fisheries governance are a source of debate and tension between the Indigenous Mi’kmaq people of Nova Scotia and the Canadian Department of Fisheries and Oceans (DFO in matters concerning Atlantic salmon, Salmo salar. Within the context of the existing governance regime, this analysis compares the concept of salmon conservation and management from a Mi’kmaq perspective and proposes a collaborative co-existence approach for effective salmon governance in Nova Scotia. This approach begins by using co-management as a process, Two-Eyed Seeing as the design, and treaties as the model to achieve shared objectives of maintaining and improving abundances of salmon populations, in spite of differing mechanisms for addressing the interwoven complexities of multiple realities, conservation, and cultural identity.

  16. Co-existence of clonal expanded autologous and transplacental-acquired maternal T cells in recombination activating gene-deficient severe combined immunodeficiency.

    Science.gov (United States)

    Lev, A; Simon, A J; Ben-Ari, J; Takagi, D; Stauber, T; Trakhtenbrot, L; Rosenthal, E; Rechavi, G; Amariglio, N; Somech, R

    2014-06-01

    It is commonly accepted that the presence of high amounts of maternal T cells excludes Omenn syndrome (OS) in severe combined immunodeficiency (SCID). We report a SCID patient with a novel mutation in the recombination activating gene (RAG)1 gene (4-BP DEL.1406 TTGC) who presented with immunodeficiency and OS. Several assays, including representatives of specific T cell receptors (TCR), Vβ families and TCR-γ rearrangements, were performed in order to understand more clearly the nature and origin of the patient's T cells. The patient had oligoclonal T cells which, based on the patient-mother human leucocyte antigen (HLA)-B50 mismatch, were either autologous or of maternal origin. These cell populations were different in their numbers of regulatory T cells (T(reg)) and the diversity of TCR repertoires. This is the first description of the co-existence of large amounts of clonal expanded autologous and transplacental-acquired maternal T cells in RAG1-deficient SCID.

  17. Ontogeny of the VIP system in the gastro-intestinal tract of the Axolotl, Ambystoma mexicanum: successive appearance of co-existing PACAP and NOS.

    Science.gov (United States)

    Badawy, Gamal; Reinecke, Manfred

    2003-03-01

    Evidence for the presence and potential co-existence of vasoactive intestinal polypeptide (VIP), pituitary adenylate cyclase-activating polypeptide (PACAP) and nitric oxide synthase (NOS) in gastro-intestinal endocrine cells and/or nerve fibers is conflicting and very few results exist on development. This immunofluorescence study aims to clarify the appearance and localization of VIP, PACAP and NOS in the gastro-intestinal tract of the Axolotl, Ambystoma mexicanum, during ontogeny. VIP-immunoreactivity appeared in nerve fibers as early as on day 3 after hatching likely indicating a particular role, such as a trophic action, of VIP in very early development. PACAP-immunoreactivity was observed 3 days later within the VIP-immunoreactive (-IR) fibers. From this time on, VIP- and PACAP-immunoreactivity exhibited complete co-existence. VIP/PACAP-IR fibers were found throughout the gastro-intestinal tract. They were most prominent in the myenteric plexus and the muscle layers and less frequent in the submucosa. NOS-immunoreactivity appeared as late as at the 1st (64 days) juvenile stage in a subpopulation of the VIP/PACAP-IR fibers that contacted submucosal arteries. We found only very few VIP/PACAP-IR perikarya, indicating that part of the VIP/PACAP-IR fibers is of extrinsic origin. On day 12 and in the 1st and 2nd (104 days) juvenile stage, infrequent PACAP-IR entero-endocrine cells were noted, while neither VIP- nor NOS-immunoreactivity occurred in endocrine cells at any stage of development. The complete coexistence of neuronal PACAP- and VIP-immunoreactivities and their very early appearance in ontogeny may suggest important and coordinated roles of both peptides in the control of Axolotl gastro-intestinal activity, while the VIP/ PACAP/NOS-IR fibers may be involved in the regulation of submucosal blood flow.

  18. Co-existence of urinary tract infection and malaria among children under five years old: A report from Benin City, Nigeria

    Directory of Open Access Journals (Sweden)

    P O Okunola

    2012-01-01

    Full Text Available Children with fever are a majority in the various emergency rooms all over the world, and especially in the tropics. Most in sub-Saharan Africa will be treated for malaria, whether confirmed or not. It therefore follows that some of the morbidities other than malaria may go undiagnosed. The comorbidities with malaria that may have similar presentation among under-fives therefore are difficult to detect, and diseases like respiratory tract infections and urinary tract infections (UTI are left to debilitate affected children. The exact burden of UTI co-existing with malaria in Nigeria remains ill defined. This study looks at the co-existence of UTI in under- fives with a primary diagnosis of malaria. Well-nourished children aged less than five years with confirmed malaria seen at the Children Emergency Room of the University of Benin Teaching Hospital were recruited into a prospective cross-sectional study between June and August 2006. The prevalence of UTI was 9% (27 of 300 children, with those aged less than 24 months comprising the majority. The uropathogens isolated included Staphylococcus aureus (55.6%, Escherichia coli (29.6% and Kleibsiella pneumonia (14.8%. The isolates demonstrated high in vitro sensitivity to clavulanic acid-potentiated amoxicillin, ciprofloxacin and gentamicin, but were resistant to other commonly used antibiotics like amoxicillin and co-trimoxazole. The study indicates that UTI is a silent comorbidity in children aged less than 5 years with malaria and there is a need to evaluate these children in order to prevent the long-term morbidity of chronic renal diseases.

  19. Improvement of catalytic activity in selective oxidation of styrene with H{sub 2}O{sub 2} over spinel Mg–Cu ferrite hollow spheres in water

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Jinhui, E-mail: jinhuitong@126.com [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education, Lanzhou 730070 (China); Key Laboratory of Gansu Polymer Materials, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Cai, Xiaodong; Wang, Haiyan; Zhang, Qianping [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education, Lanzhou 730070 (China); Key Laboratory of Gansu Polymer Materials, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2014-07-01

    Graphical abstract: Uniform spinel Mg–Cu ferrite hollow spheres were prepared using carbon spheres as templates. Solid spinel Mg{sub 0.5}Cu{sub 0.5}Fe{sub 2}O{sub 4} ferrite nanocrystals were also prepared by sol–gel auto-combustion, hydrothermal and coprecipitation methods for comparison. The samples were found to be efficient catalysts for oxidation of styrene using hydrogen peroxide as oxidant. Especially, in the case of Mg{sub 0.5}Cu{sub 0.5}Fe{sub 2}O{sub 4} hollow spheres, obvious improvement on catalytic activity was observed and 21.2% of styrene conversion and 75.2% of selectivity for benzaldehyde were obtained at 80 °C for 6 h reaction in water. The catalyst can be magnetically separated easily for reuse and no obvious loss of activity was observed when reused in six consecutive runs. - Highlights: • Uniform spinel ferrite hollow spheres were prepared by a simple method. • The catalyst has been proved much more efficient for styrene oxidation than the reported analogues. • The catalyst can be easily separated by external magnetic field and has exhibited excellent reusability. • The catalytic system is environmentally friendly. - Abstract: Uniform spinel Mg–Cu ferrite hollow spheres were prepared using carbon spheres as templates. For comparison, solid Mg–Cu ferrite nanocrystals were also prepared by sol–gel auto-combustion, hydrothermal and coprecipitation methods. All the samples were characterized by Fourier transform infrared spectrophotometry (FT-IR), X-ray diffractometry (XRD), transmission electron microscopy (TEM) and N{sub 2} physisorption. The samples were found to be efficient catalysts for oxidation of styrene using hydrogen peroxide as oxidant. Especially, in the case of Mg{sub 0.5}Cu{sub 0.5}Fe{sub 2}O{sub 4} hollow spheres, obvious improvement on catalytic activity was observed, and 21.2% of styrene conversion and 75.2% of selectivity for benzaldehyde were obtained at 80 °C for 6 h reaction in water. The catalyst can be

  20. Co-existence of Paragonimus harinasutai and Paragonimus bangkokensis metacercariae in fresh water crab hosts in central Viet Nam with special emphasis on their close phylogenetic relationship.

    Science.gov (United States)

    Doanh, Pham Ngoc; Hien, Hoang Van; Nonaka, Nariaki; Horii, Yoichiro; Nawa, Yukifumi

    2012-09-01

    During our epidemiological surveys for Paragonimus species in central Viet Nam, we found four morphologically different Paragonimus metacercariae in mountainous crabs. They were identified as metacercariae of Paragonimus westermani, P. bangkokensis, P. proliferus, and P. harinasutai in the order of their prevalence in crab hosts. This is the first discovery of P. harinasutai in Viet Nam, co-inhabiting with P. bangkokensis and other species. Metacercariae of P. harinasutai were given orally to a cat to obtain adult worms. Then, ITS2 and CO1 sequences of metacercariae and adults of P. harinasutai, and metacercariae of P. bangkokensis collected from the same place were determined for analyses of phylogenetic relationships to other P. harinasutai and P. bangkokensis populations as well as related species. The results of molecular analyses showed that P. harinasutai from Quang Binh province of central Viet Nam was almost completely identical with those from Vientiane, Lao PDR; P. bangkokensis from Quang Binh, Viet Nam was also almost completely identical with those from Lao PDR and from Quang Ninh province, Viet Nam. Except for one P. harinasutai isolate from China, all populations of P. harinasutai and P. bangkokensis from Thailand, Lao and Viet Nam make a single clade in both ITS2 and CO1 trees. In ITS2 sequences, AT deletion and ATC insertion were observed in some isolates of both species, indicating recent gene flow between P. harinasutai and P. bangkokensis. Moreover, because of their extremely high genetic similarities and their co-inhabitation in the same crab hosts found in Thailand, Lao PDR and Viet Nam, they should be considered as the sister species at the early stage of divergence. In addition, P. microrchis previously described from Yunnan, China should be placed as the synonym of P. harinasutai, because of their morphological and molecular similarities.

  1. Thermal desorption study of catalytic systems. Communication 20. Adsorption of water vapors on the calcium aluminate components of catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Nissenbaum, V.D.; Danyushevskii, V.Y.; Golosman, E.Z.; Rubinstein, A.M.; Yakerson, V.I.

    1985-05-01

    Ca aluminates are used as a component of catalysts of gas-phase processes, some of which take place with the participation of water. Nickel calcium aluminate catalysts are thus used for hydrogenation of CO and CO/sub 2/ to CH/sub 4/ and water; zinc calcium aluminate catalysts are used for sulfur purification of process gases, where water is liberated during sulfiding of ZnO; and copper zinc calcium aluminate catalysts are used in low-temperature conversion of CO with water vapor. It is also known that Ca aluminates undergo various transformations in aqueous media with the formation of Ca hydroaluminates. This paper discusses the adsorption of water from the gas phase on calcium aluminate systems, which was investigated by the thermal desorption method. Samples of varying phase composition, different CaO/Al/sub 2/O/sub 3/ ratios, and specific surface areas were also studied and are reported on here.

  2. Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification.

    Science.gov (United States)

    Castro-Dominguez, Bernardo; Mardilovich, Ivan P; Ma, Liang-Chih; Ma, Rui; Dixon, Anthony G; Kazantzis, Nikolaos K; Ma, Yi Hua

    2016-09-19

    Palladium-based catalytic membrane reactors (CMRs) effectively remove H₂ to induce higher conversions in methane steam reforming (MSR) and water-gas-shift reactions (WGS). Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H₂, CO and CO₂. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H₂O, CO₂ and H₂. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H₂ and induce higher methane and CO conversions while yielding ultrapure H₂ and compressed CO₂ ready for dehydration. Experimental results involving (i) a conventional packed bed reactor packed (PBR) for MSR, (ii) a PBR with five layers of two catalysts in series and (iii) a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD) model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H₂ permeance and purity, high CH₄ conversion levels and reduced CO yields.

  3. The catalytic role of the water or acidic zeolite in the oxidation of BrCH2OH. A theoretical study

    Science.gov (United States)

    Papayannis, Demetrios K.; Kosmas, Agnie M.

    2016-11-01

    We present a computational investigation of the catalytic activity of the water molecules or acidic zeolite in the oxidation of bromomethanol, coming from the degradation of brominated organic compounds in the natural environment. The role of the water in this mechanism has been established using MP2(full)/6-311++G(3df, 2p) level of theory. Energetic results were further refined by CCSD(T) calculations, using optimized geometric parameters of the MP2 level. The computational investigation shows clearly the dramatic reduction of the activation energy of the oxidation to formaldehyde that occurs when explicit coordination of water molecules is taken into account. Further investigation of the degradation mechanism has been carried out by considering the oxidation reaction as taking place on acidic zeolite surface, with the help of the hybrid (QM/MM) approximation and specifically the two-layered, ONIOM2 methodology at the (MP2(full)/6-31G∗:UFF) and (M06-2X/6-311++G(3df, 2p):UFF) levels of theory.

  4. Effects of natural water ions and humic acid on catalytic nitrate reduction kinetics using an alumina supported Pd-Cu catalyst.

    Science.gov (United States)

    Chaplin, Brian P; Roundy, Eric; Guy, Kathryn A; Shapley, John R; Werth, Charles J

    2006-05-01

    Catalytic nitrate reduction was evaluated for the purpose of drinking water treatment. Common anions present in natural waters and humic acid were evaluated for their effects on NO3(-) hydrogenation over a bimetallic supported catalyst (Pd-Cu/gamma-Al2O3). Groundwater samples, with and without powder activated carbon (PAC) pretreatment, were also evaluated. In the absence of inhibitors the NO3- reduction rate was 2.4 x 10(-01) L/min g cat. However, the addition of constituents (SO4(2-), SO3(2-), HS-, CI-, HCO3-, OH-, and humic acid) on the order of representative concentrations for drinking water decreased the NO3- reduction rate. Sulfite, sulfide, and elevated chloride decreased the NO3- reduction rate by over 2 orders of magnitude. Preferential adsorption of Cl- inhibited NO3- reduction to a greater extent than NO2- reduction. Partial regeneration of catalysts exposed to SO3(2-) was achieved by using a dilute hypochlorite solution, however Cu dissolution occurred. Dissolved constituents in the groundwater sample decreased the NO3- reduction rate to 3.7 x 10(-03) L/min g cat and increased ammonia production. Removal of dissolved organic matter from the groundwater using PAC increased the NO3- reduction rate to 5.06 x 10(-02) L/min g cat and decreased ammonia production. Elemental analyses of catalysts exposed to the natural groundwater suggest that mineral precipitation may also contribute to catalyst fouling.

  5. [State of Fungal Lipases of Rhizopus microsporus, Penicillium sp. and Oospora lactis in Border Layers Water-Solid Phase and Factors Affecting Catalytic Properties of Enzymes].

    Science.gov (United States)

    Khasanov, Kh T; Davranov, K; Rakhimov, M M

    2015-01-01

    We demonstrated that a change in the catalytic activity of fungal lipases synthesized by Rhizopus microsporus, Penicillium sp. and Oospora lactis and their ability to absorb on different sorbents depended on the nature of groups on the solid phase surface in the model systems water: lipid and water: solid phase. Thus, the stability of Penicillium sp. lipases increased 85% in the presence ofsorsilen or DEAE-cellulose, and 55% of their initial activity respectively was preserved. In the presence of silica gel and CM-cellulose, a decreased rate of lipid hydrolysis by Pseudomonas sp. enzymes was observed in water medium, and the hydrolysis rate increased by 2.4 and 1.5 times respectively in the presence of aminoaerosil and polykefamid. In an aqueous-alcohol medium, aminoaerosil and polykefamid decreased the rate of substrate hydrolysis by more than 30 times. The addition of aerosil to aqueous and aqueous-alcohol media resulted in an increase in the hydrolysis rate by 1.2-1.3 times. Sorsilen stabilized Penicillium sp. lipase activity at 40, 45, 50 and 55 degrees C. Either stabilization or inactivation of lipases was observed depending on the pH of the medium and the nature of chemical groups localized on the surface of solid phase. The synthetizing activity of lipases also changed depending on the conditions.

  6. Science Letters: Structure relationship of nitrochlorobenzene catalytic degradation process in water over palladium-iron bimetallic catalyst

    Institute of Scientific and Technical Information of China (English)

    NIU Shao-feng; ZHOU Hong-yi; AO Xu-ping; XU Xin-hua; LOU Zhang-hua

    2006-01-01

    Two isomers of nitrochlorobenzene (o-, and p-NCB) were treated by a Pd/Fe catalyst in aqueous solutions through catalytic amination and dechlorination. Nitrochlorobenzenes are rapidly converted to form chloroanilines (CAN) first through an amination process, and then rapidly dechlorinated to become aniline (AN) and Cl-, without the involvement of any other intermediate reaction products. The amination and dechlorination reaction are believed to take place predominantly on the surface site of the Pd/Fe catalysts. The dechlorination rate of the reductive degradation of the two isomers of nitrochlorobenzene (o-, and p-NCB) in the presence of Pd/Fe as a catalyst was measured experimentally. In all cases, the reaction rate constants were found to increase with the decrease in the Gibbs free energy (correlation with the activation energy) of NCBs formation; the activation energy of each dechlorination reaction was measured to be 95.83 and 77.05 kJ/mol, respectively for o- and p-NCB. The results demonstrated that p-NCBs were reduced more easily than o-NCBs.

  7. Analysis on Affecting Factors and Kinetics of Wastewater Treatment by Catalytic Supercritical Water Oxidation%废水处理催化超临界水氧化法影响因素及动力学分析

    Institute of Scientific and Technical Information of China (English)

    韦朝海; 王刚; 谢波

    2000-01-01

    Affecting factors and kinetics by catalytic supercritical water oxidation were summed up,and the importance of catalyst in the process of catalytic supercritical water oxidation was emphasised. In addition,general kinetic model for catalytic supercritical water oxidation was deduced. Kinetic parameters and reacting conditions of organic compounds including phenol ,acetic acid and pyridine are expounded. The performance of complex compounds by catalytic supercritical water oxidation was discussed based on the above results. All of which offers theoretical guidance for waste water treatment. In the end,some suggestions were proposed for scale-up and engineering utilization of catalytic supercritical water oxidation.%归纳了催化超临界水氧化法的影响因素并分析其相互间的关系,阐明催化剂作用的重要性。此外,论文还推导了反应体系普遍的动力学模型,分别分析了环状化合物、难降解中间产物及含氮化合物的动力学特征参数及反应条件的制约关系,在此基础上讨论复杂有机化合物废水的反应动力学行为,以期为实际废水处理提供理论指导。论文的最后对催化超临界水氧化法的工程开发与实际应用化问题提出了若干构想与建议。

  8. Enhancement of reaction rates for catalytic benzaldehyde hydrogenation and sorbitol dehydration in water solvent by addition of carbon dioxide

    Indian Academy of Sciences (India)

    Masayuki Shirai; Osamu Sato; Norihito Hiyoshi; Aritomo Yamaguchi

    2014-03-01

    The effect of pressured carbon dioxide on heterogeneous hydrogenation of benzaldehyde and homogeneous dehydration of sorbitol in water solvent was studied. Initial hydrogenation rates of benzaldehyde over a charcoal-supported palladium catalyst in water at 313 K were enhanced by the addition of carbon dioxide. The initial rate increased with an increase in carbon dioxide pressure and became a maximum at 5 MPa. Dehydration of sorbitol proceeded in water phase at 500 K and initial dehydration rates were enhanced by addition of 30 MPa of carbon dioxide.

  9. Novel Catalytic Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Nemser, PhD

    2010-10-01

    There are many industrial catalytic organic reversible reactions with amines or alcohols that have water as one of the products. Many of these reactions are homogeneously catalyzed. In all cases removal of water facilitates the reaction and produces more of the desired chemical product. By shifting the reaction to right we produce more chemical product with little or no additional capital investment. Many of these reactions can also relate to bioprocesses. Given the large number of water-organic compound separations achievable and the ability of the Compact Membrane Systems, Inc. (CMS) perfluoro membranes to withstand these harsh operating conditions, this is an ideal demonstration system for the water-of-reaction removal using a membrane reactor. Enhanced reaction synthesis is consistent with the DOE objective to lower the energy intensity of U.S. industry 25% by 2017 in accord with the Energy Policy Act of 2005 and to improve the United States manufacturing competitiveness. The objective of this program is to develop the platform technology for enhancing homogeneous catalytic chemical syntheses.

  10. 催化水煤气变换反应的计算模拟进展%Progress of theoretical simulation of catalytic water-gas-shift reaction

    Institute of Scientific and Technical Information of China (English)

    陈玉; 张福丽; 姚辉超; 刘植昌; 崔佳; 徐春明

    2012-01-01

    The progress of theoretical simulation of catalytic water-gas-shift(WGS) reaction is reviewed,by focusing on the reaction mechanism.As to traditional Cu-Zn-,Fe-Cr-,and Co-Mo-based heterogeneous catalysts,carboxyl and redox mechanisms dominate.Promoters and supports also affect the entire reaction process,and may take part in the reaction process directly.Improved or novel catalysts,such as gold or gold-loaded catalyst have also been explored theoretically,and there is also no end to apprehending respective catalytic reaction mechanism.For those homogeneous catalytic reactions like WGS catalyzed by carbonyls of iron group,the understanding of the reaction mechanism is getting deeper.Theoretical studies are expected to expand from those simple model systems to more complex and real WGS model systems.Theoretical studies will show their advantages,such as convenience and low cost,in comparison with experimental investigation,and also provide successful examples for the design of catalysts.%综述了对具有广泛工业应用的水煤气变换(WGS)反应进行理论模拟所取得的进展,重点讨论反应机理方面获得的成果。对于传统的铜锌、铁铬和钴钼等非均相催化剂而言,羧基机理和氧化还原机理占统治地位,而助剂和载体对反应机理也有影响,有时甚至直接参与反应过程。对改进型、新型催化剂如金或负载金等催化WGS反应机理的认识过程尚未结束。对铁族羰基络合均相催化WGS反应机理的理解逐步深入。理论模拟研究将从少数简单的WGS模型体系扩展到更多复杂的真实体系;在预言新的催化体系反应机理上,与实验研究相比,有望体现出费用低和非常便利的优势,并能为催化剂的设计提供理论依据和成功案例。

  11. Water-dispersible Hollow Microporous Organic Network Spheres as Substrate for Electroless Deposition of Ultrafine Pd Nanoparticles with High Catalytic Activity and Recyclability.

    Science.gov (United States)

    Wang, Zhifang; Chang, Jing; Hu, Yuchen; Yu, Yifu; Guo, Yamei; Zhang, Bin

    2016-11-22

    Microporous organic networks (MONs) have been considered as an ideal substrate to stabilize active metal nanoparticles. However, the development of highly water-dispersible hollow MONs nanostructures which can serve as both the reducing agent and stabilizer is highly desirable but still challenging. Here we report a template-assisted method to synthesize hollow microporous organic network (H-MON) spheres using silica spheres as hard template and 1,3,5-triethynylbenzene as the building blocks through a Glaser coupling reaction. The obtained water-dispersible H-MON spheres bearing sp- and sp(2) -hybridized carbon atoms possess a highly conjugated electronic structure and show low reduction potential; thus, they can serve as a reducing agent and stabilizer for electroless deposition of highly dispersed Pd clusters to form a Pd/H-MON spherical hollow nanocomposite. Benefitting from their high porosity, large surface area, and excellent solution dispersibility, the as-prepared Pd/H-MON hollow nanocomposite exhibits a high catalytic performance and recyclability toward the reduction of 4-nitrophenol.

  12. Characterization of a trinuclear ruthenium species in catalytic water oxidation by Ru(bda)(pic)2 in neutral media.

    Science.gov (United States)

    Zhang, Biaobiao; Li, Fei; Zhang, Rong; Ma, Chengbing; Chen, Lin; Sun, Licheng

    2016-06-30

    A Ru(III)-O-Ru(IV)-O-Ru(III) type trinuclear species was crystallographically characterized in water oxidation by Ru(bda)(pic)2 (H2bda = 2,2'-bipyridine-6,6'-dicarboxylic acid; pic = 4-picoline) under neutral conditions. The formation of a ruthenium trimer due to the reaction of Ru(IV)[double bond, length as m-dash]O with Ru(II)-OH2 was fully confirmed by chemical, electrochemical and photochemical methods. Since the oxidation of the trimer was proposed to lead to catalyst decomposition, the photocatalytic water oxidation activity was rationally improved by the suppression of the formation of the trimer.

  13. FIB synthesis of Bi2Se3 1D nanowires demonstrating the co-existence of Shubnikov-de Haas oscillations and linear magnetoresistance

    Science.gov (United States)

    Bhattacharyya, Biplab; Sharma, Alka; Awana, V. P. S.; Senguttuvan, T. D.; Husale, Sudhir

    2017-02-01

    Since the discovery of topological insulators (TIs), there are considerable interests in demonstrating metallic surface states (SS), their shielded robust nature to the backscattering and study their properties at nanoscale dimensions by fabricating nanodevices. Here we address an important scientific issue related to TI whether one can clearly demonstrate the robustness of topological surface states (TSS) to the presence of disorder that does not break any fundamental symmetry. The simple straightforward method of FIB milling was used to synthesize nanowires of Bi2Se3 which we believe is an interesting route to test robustness of TSS and the obtained results are new compared to many of the earlier papers on quantum transport in TI demonstrating the robustness of metallic SS to gallium (Ga) doping. In the presence of perpendicular magnetic field, we have observed the co-existence of Shubnikov-de Haas oscillations and linear magnetoresistance (LMR), which was systematically investigated for different channel lengths, indicating the Dirac dispersive surface states. The transport properties and estimated physical parameters shown here demonstrate the robustness of SS to the fabrication tools triggering flexibility to explore new exotic quantum phenomena at nanodevice level.

  14. FIB synthesis of Bi2Se3 1D nanowires demonstrating the co-existence of Shubnikov-de Haas oscillations and linear magnetoresistance.

    Science.gov (United States)

    Bhattacharyya, Biplab; Sharma, Alka; Awana, V P S; Senguttuvan, T D; Husale, Sudhir

    2017-02-22

    Since the discovery of topological insulators (TIs), there are considerable interests in demonstrating metallic surface states (SS), their shielded robust nature to the backscattering and study their properties at nanoscale dimensions by fabricating nanodevices. Here we address an important scientific issue related to TI whether one can clearly demonstrate the robustness of topological surface states (TSS) to the presence of disorder that does not break any fundamental symmetry. The simple straightforward method of FIB milling was used to synthesize nanowires of Bi2Se3 which we believe is an interesting route to test robustness of TSS and the obtained results are new compared to many of the earlier papers on quantum transport in TI demonstrating the robustness of metallic SS to gallium (Ga) doping. In the presence of perpendicular magnetic field, we have observed the co-existence of Shubnikov-de Haas oscillations and linear magnetoresistance (LMR), which was systematically investigated for different channel lengths, indicating the Dirac dispersive surface states. The transport properties and estimated physical parameters shown here demonstrate the robustness of SS to the fabrication tools triggering flexibility to explore new exotic quantum phenomena at nanodevice level.

  15. Interspecific Relationships in Benthic Assemblages of a Large Lowland River : Co-existence or Competition as a Result of Habitat Characteristics

    Science.gov (United States)

    Akopian, M.; Usseglio-Polatera, P.

    2005-05-01

    Macrobenthic assemblages of the lower, regulated and canalized Marne River (France) are dominated by several "exotic", recently introduced species. Arrival, installation and spread of such alien species were certainly promoted by (1) the close connection between French and other European river systems (Rhine, Danube), (2) the modification of natural river flow and benthic habitats. Both habitat characteristics (e.g. granulometric composition, organic content) and corresponding benthic assemblage structure were analysed to identify the substrate affinity of major taxa in the lower Marne River. The main aim of the study was to evaluate the possible biotic interactions (i.e. competition for food and/or space) among dominant taxa as function of habitat features and to predict the future development of newly established species, already known as potential invaders: Corbicula fluminea (Bivalvia), Hypania invalida (Polychaeta), Chelicorophium curvispinum (Amphipoda), etc. Most of the newly established species, coming from the same biogeographical area ("invasional meltdown" hypothesis?), are eurytopic, with high fecundity and large food spectrum. First results demonstrated the co-existence of such species in the Marne River. But the future ecological importance of these organisms in benthic assemblages of the river depends on their present population size, population dynamics, and ability to colonize bottom substrates.

  16. Stable solar-driven oxidation of water by semiconducting photoanodes protected by transparent catalytic nickel oxide films

    KAUST Repository

    Sun, Ke

    2015-03-11

    Reactively sputtered nickel oxide (NiOx) films provide transparent, antireflective, electrically conductive, chemically stable coatings that also are highly active electrocatalysts for the oxidation of water to O2(g). These NiOx coatings provide protective layers on a variety of technologically important semiconducting photoanodes, including textured crystalline Si passivated by amorphous silicon, crystalline n-type cadmium telluride, and hydrogenated amorphous silicon. Under anodic operation in 1.0 M aqueous potassium hydroxide (pH 14) in the presence of simulated sunlight, the NiOx films stabilized all of these self-passivating, high-efficiency semiconducting photoelectrodes for >100 h of sustained, quantitative solar-driven oxidation of water to O2(g). © 2015, National Academy of Sciences. All rights reserved.

  17. The use of ozonation and catalytic ozonation combined with ultrafiltration for the control of natural organic matter (NOM) and disinfection by-products (DBPs) in drinking water

    Science.gov (United States)

    Karnik, Bhavana Sushilkumar

    Commercially available titania membranes, with a molecular weight cut-off of 15, 5, 1 kD were used in a ozonation/membrane system that was fed with water from Lake Lansing. The effects of ozonation on permeate flux recovery and membrane fouling was investigated. In addition the effects of ozonation/membrane filtration hybrid process on the removal of the natural organic matter (NOM) and the formation of disinfection by-products (DBPS) were monitored. The commercial membrane (CeRAM Inside, Tami North America, St. Laurent, Quebec, Canada) was coated with iron oxide nanoparticles (4--6 nm in diameter) using a layer-by-layer technique and sintered in air for 30 minutes. Surface characterization was carried out using electron microscopy techniques and atomic force microscopy, to study the changes in structure and surface morphology of the membranes. The removal and survival of bacteria in the process was also evaluated using fluorescence microscopy and microbial assays. Finally the surface catalytic reaction was investigated to propose the mechanism responsible for the improved performance of the hybrid process. The permeate flux through a titania coated ceramic membrane was significantly affected by ozonation. A minimum threshold ozone concentration (2.5 g/m 3) could achieve complete recovery of permeate flux after fouling. Ozonation/filtration decreased the concentration of chlorinated disinfection by-products up to 80%. With catalyst coated membranes, the concentration of dissolved organic carbon was reduced by >85% and the concentrations of disinfection by-products decreased by up to 90%. Furthermore with the coated membrane, the concentrations of ozonation by-products in the permeate were reduced by >50% as compared to that obtained with the uncoated membranes, thus reducing the risk of potential regrowth of bacteria in the distribution system. Application of the hybrid process lead to greater than 7 log removal of bacteria. Surface characterization showed that

  18. Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification

    Science.gov (United States)

    Castro-Dominguez, Bernardo; Mardilovich, Ivan P.; Ma, Liang-Chih; Ma, Rui; Dixon, Anthony G.; Kazantzis, Nikolaos K.; Ma, Yi Hua

    2016-01-01

    Palladium-based catalytic membrane reactors (CMRs) effectively remove H2 to induce higher conversions in methane steam reforming (MSR) and water-gas-shift reactions (WGS). Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H2, CO and CO2. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H2O, CO2 and H2. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H2 and induce higher methane and CO conversions while yielding ultrapure H2 and compressed CO2 ready for dehydration. Experimental results involving (i) a conventional packed bed reactor packed (PBR) for MSR, (ii) a PBR with five layers of two catalysts in series and (iii) a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD) model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H2 permeance and purity, high CH4 conversion levels and reduced CO yields. PMID:27657143

  19. Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification

    Directory of Open Access Journals (Sweden)

    Bernardo Castro-Dominguez

    2016-09-01

    Full Text Available Palladium-based catalytic membrane reactors (CMRs effectively remove H2 to induce higher conversions in methane steam reforming (MSR and water-gas-shift reactions (WGS. Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H2, CO and CO2. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H2O, CO2 and H2. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H2 and induce higher methane and CO conversions while yielding ultrapure H2 and compressed CO2 ready for dehydration. Experimental results involving (i a conventional packed bed reactor packed (PBR for MSR, (ii a PBR with five layers of two catalysts in series and (iii a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H2 permeance and purity, high CH4 conversion levels and reduced CO yields.

  20. Catalytic ozonation of trace sulfadiazine in water by ZnOOH%羟基化锌催化臭氧氧化去除水中痕量磺胺嘧啶

    Institute of Scientific and Technical Information of China (English)

    周宁娟; 薛罡; 卜聃; 刘亚男

    2011-01-01

    ZnOOH prepared in laboratory was used as a catalyst in the ozonation of trace sulfadiazine (SD) in water.The catalytic mechanism was deduced base on the effect of radical inhibitor t-BuOH on the reaction.The influences of O3dose,water quality parameters (pH, chloride anion concentration), catalyst dose and catalyst reuse on the SD removal were also examined.ZnOOH had excellent catalytic activity in SD ozonation.The hydroxyl groups combined on the catalyst surfaces played a part in the catalytic reactions.The removal of SD dissolved in distilled water increased by 47.7% at reaction time of 30min in ozonation with zinc hydroxide compared to the ozonation without catalyst under optimal conditions.The catalytic reaction process followed a hydroxyl radical reaction mechanism and the SD removal improved with increasing dosage of catalyst.ZnOOH can be reused for several times without obvious reduction of catalytic activity and Cl in water could greatly decrease the catalytic activity of ZnOOH.The optimal catalytic activity of ZnOOH achieved at weak basic solution.%以实验室制备的羟基化锌(ZnOOH)为催化剂,研究了其催化臭氧化去除水中痕量磺胺嘧啶(SD)的效能,通过研究叔丁醇对催化效果的影响,推断了催化反应机理,探讨了臭氧投加量、水质因素、催化剂投加量和使用次数对催化性能的影响因素.结果表明,ZnOOH对臭氧氧化水中的SD有较强的催化活性.催化剂表面结合的羟基基团有利于催化反应.在优化的实验条件下,蒸馏水中反应30min时,催化臭氧化比单独臭氧化对SD的去除率提高了47.7%.催化过程遵循自由基反应机理,SD的去除效果随催化剂投加量的增加而提高,催化剂在重复使用后催化效果基本不变,水中的氯离子可以明显降低催化剂的活性,偏碱性条件下,催化效果更佳.

  1. Modelling Niche Differentiation of Co-Existing, Elusive and Morphologically Similar Species: A Case Study of Four Macaque Species in Nakai-Nam Theun National Protected Area, Laos.

    Science.gov (United States)

    Coudrat, Camille N Z; Nekaris, K Anne-Isola

    2013-01-30

    Species misidentification often occurs when dealing with co-existing and morphologically similar species such as macaques, making the study of their ecology challenging. To overcome this issue, we use reliable occurrence data from camera-trap images and transect survey data to model their respective ecological niche and potential distribution locally in Nakai-Nam Theun National Protected Area (NNT NPA), central-Eastern Laos. We investigate niche differentiation of morphologically similar species using four sympatric macaque species in NNT NPA, as our model species: rhesus Macaca mulatta (Taxonomic Serial Number, TSN 180099), Northern pig-tailed M. leonina (TSN not listed); Assamese M. assamensis (TSN 573018) and stump-tailed M. arctoides (TSN 573017). We examine the implications for their conservation. We obtained occurrence data of macaque species from systematic 2006-2011 camera-trapping surveys and 2011-2012 transect surveys and model their niche and potential distribution with MaxEnt software using 25 environmental and topographic variables. The respective suitable habitat predicted for each species reveals niche segregation between the four species with a gradual geographical distribution following an environmental gradient within the study area. Camera-trapping positioned at many locations can increase elusive-species records with a relatively reduced and more systematic sampling effort and provide reliable species occurrence data. These can be used for environmental niche modelling to study niche segregation of morphologically similar species in areas where their distribution remains uncertain. Examining unresolved species' niches and potential distributions can have crucial implications for future research and species' management and conservation even in the most remote regions and for the least-known species.

  2. Co-existence of calcium-binding proteins and γ-aminobutyric acid or glycine in neurons of the rat medullary dorsal horn

    Institute of Scientific and Technical Information of China (English)

    王文; 武胜昔; 李云庆

    2004-01-01

    Background We investigated the co-expression of calbindin-D28k (CB), calretinin (CR) and parvalbumin (PV, a combination of the three is referred to as CaBPs) with γ-aminobutyric acid (GABA) or glycine in neurons of the rat medullary dorsal horn (MDH).Methods Immunofluorescence histochemical double-staining for CaBPs and GABA or glycine was performed on the sections from rat MDH.Results CB-, CR-, PV-, GABA- and glycine-like immunoreactive (LI) neurons were differentially observed in all layers of the MDH, but particularly in lamina Ⅱ. Neurons that exhibited immunoreactivity for both CaBPs and GABA or glycine were also observed mainly in lamina Ⅱ. A few of them were found in laminae I and III. The percentages of neurons which co-expressed CB/GABA or CB/glycine out of the total numbers of CB- and GABA-LI neurons or CB- and glycine-LI neurons were 5.3% and 12.1% or 4.1% and 10.0%, respectively. The ratios of CR/GABA or CR/glycine co-existing neurons out of the total numbers of CR- and GABA-LI neurons or CR- and glycine-LI neurons were 5.8% and 7.6% or 4.4% and 7.1%, respectively. The rates of PV/GABA or PV/glycine co-localized neurons out of the total numbers of PV- and GABA-LI neurons or PV- and glycine-LI neurons were 11.1% and 5.1% or 9.9% and 5.1%, respectively. Conclusion The results indicate that some neurons in the MDH contain both CaBPs and GABA or glycine.

  3. Modelling Niche Differentiation of Co-Existing, Elusive and Morphologically Similar Species: A Case Study of Four Macaque Species in Nakai-Nam Theun National Protected Area, Laos

    Directory of Open Access Journals (Sweden)

    Camille N. Z. Coudrat

    2013-01-01

    Full Text Available Species misidentification often occurs when dealing with co-existing and morphologically similar species such as macaques, making the study of their ecology challenging. To overcome this issue, we use reliable occurrence data from camera-trap images and transect survey data to model their respective ecological niche and potential distribution locally in Nakai-Nam Theun National Protected Area (NNT NPA, central-Eastern Laos. We investigate niche differentiation of morphologically similar species using four sympatric macaque species in NNT NPA, as our model species: rhesus Macaca mulatta (Taxonomic Serial Number, TSN 180099, Northern pig-tailed M. leonina (TSN not listed; Assamese M. assamensis (TSN 573018 and stump-tailed M. arctoides (TSN 573017. We examine the implications for their conservation. We obtained occurrence data of macaque species from systematic 2006–2011 camera-trapping surveys and 2011–2012 transect surveys and model their niche and potential distribution with MaxEnt software using 25 environmental and topographic variables. The respective suitable habitat predicted for each species reveals niche segregation between the four species with a gradual geographical distribution following an environmental gradient within the study area. Camera-trapping positioned at many locations can increase elusive-species records with a relatively reduced and more systematic sampling effort and provide reliable species occurrence data. These can be used for environmental niche modelling to study niche segregation of morphologically similar species in areas where their distribution remains uncertain. Examining unresolved species' niches and potential distributions can have crucial implications for future research and species' management and conservation even in the most remote regions and for the least-known species.

  4. Co-existence of Pseudomonas-derived cephalosporinase among plasmid encoded CMY-2 harbouring isolates of Pseudomonas aeruginosa in north India

    Directory of Open Access Journals (Sweden)

    S Upadhyay

    2013-01-01

    Full Text Available Context: In Pseudomonas aeruginosa, AmpC β-lactamases are often responsible for high-level resistance to β-lactam antibiotics. The co-production of plasmid-mediated AmpC along with chromosomal Pseudomonas-derived cephalosporinases thus remain a serious clinical concern owing to high resistance spectrum towards antibiotics. Aim: The present study was performed to investigate the co-existence of both chromosomally-encoded and plasmid-mediated AmpC β-lactamase among clinical isolates of P. aeruginosa. Setting and Design: It is a cross-sectional study carried out in the Department of Microbiology in a tertiary referral hospital of northern India. Methods and Methods: A total of 329 consecutive, non-duplicate clinical isolates of P. aeruginosa, were selected for the detection of AmpC β-lactamases and confirmed for AmpC production by modified three dimensional (M3D test. Ceftazidime -imipenem antagonism test was used to detect inducible AmpC producers. Molecular characterisation of chromosomally-encoded blaPDC and plasmid-mediated AmpC gene was studied by performing polymerase chain reaction (PCR. Result: A total of 214 (65% isolates were confirmed for AmpC production by M3D test. On performing multiplex PCR, 27 isolates were detected posessing blaCMY type of plasmid-mediated AmpC gene. While 48 isolates were found to harbour chromosomally-encoded blaPDC gene co-production of both chromosomal and plasmid-encoded AmpC was reported in eleven isolates. Conclusions: Although these chromosomally-encoded cephalosporinases might spread more slowly than mobilised AmpC, but it is likely that in the present scenario of intense antibiotic pressure, this will become an increasing problem and may further limit our antibiotic choices.

  5. Can a safety-in-numbers effect and a hazard-in-numbers effect co-exist in the same data?

    Science.gov (United States)

    Elvik, Rune

    2013-11-01

    Safety-in-numbers denotes a non-linear relationship between exposure (traffic volume) and the number of accidents, characterised by declining risk as traffic volume increases. There is safety-in-numbers when the number of accidents increases less than proportional to traffic volume, e.g. a doubling of traffic volume is associated with less than a doubling of the number of accidents. Hazard-in-numbers, a less-used concept, refers to the opposite effect: the number of accidents increases more than in proportion to traffic volume, e.g. is more than doubled when traffic volume is doubled. This paper discusses whether a safety-in-numbers effect and a hazard-in-numbers effect can co-exist in the same data. It is concluded that both effects can exist in a given data set. The paper proposes to make a distinction between partial safety-in-numbers and complete safety-in-numbers. Another issue that has been raised in discussions about the safety-in-numbers effect is whether the effect found in some studies is an artefact created by the way exposure was measured. The paper discusses whether measuring exposure as a rate or a share, e.g. kilometres travelled per inhabitant per year, will generate a safety-in-numbers effect as a statistical artefact. It is concluded that this is the case. The preferred measure of exposure is a count of the number of road users. The count should not be converted to a rate or to the share any group of road user contribute to total traffic volume.

  6. A study of pharmacokinetic interactions among co-existing ingredients in Viscum coloratum after intravenous administration of three different preparations to rats

    Directory of Open Access Journals (Sweden)

    Yuying Ma

    2015-01-01

    Full Text Available Background: Viscum coloratum (Komar Nakai, known as Hujisheng in china, has been widely used as a herb medicine to treat a variety of diseases, including cardiovascular diseases, cancer, hypertension, hepatitis and hemorrhage. Objective: The aim was to investigate pharmacokinetic interactions among co existing ingredients in V. coloratum after intravenous administration of three different preparations (four monomer solutions, the mixture of them and Viscum coloratum extracts to rats. Materials and Methods: After protein precipitation pretreatment with plasma samples, high performance liquid chromatographic methods were developed and applied to quantitatively determinate the four components [syringin (Syri, homoeriodictyol 7 O-β-D glycoside (Hedt III, homoeriodictyol 7 O-β-D apiose (1 → 2-β-D glycoside (Hedt II and homoeriodictyol 7 O-β-D apiosiyl (1 → 5-β-D apiosyl (1 → 2-β-D glycoside (Hedt I].The pharmacokinetic parameters (Area under the curve [AUC (0-t], AUC (0-∞, t1/2 were calculated using DAS 2.1 software (Chinese Pharmacological Society,Shanghai,China and compared statistically by One way analysis of variance using SPSS software (18.0, Chicago, IL, USA with P < 0.05 considered statistically significant. Results: Good linearities were achieved in the measured concentration range with R2 it0.9920. Precision, accuracy and extraction recovery were all within the acceptable range. For Syri, there was a significant difference only on t1/2 among three treatment groups. For Hedt I, Hedt II and Hedt III, three flavonoid glycosides, the change of AUC (0-t, AUC (0-∞ and t1/2 were markedly distinctive and even converse. Conclusion: Complex, extensive pharmacokinetic interactions were observed among these components in V. coloratum. They were mutually influenced by the in vivo absorption, distribution, metabolism and elimination. The result suggested traditional Chinese medicine was a complicated system, and we should take a scientific

  7. Phase Behaviour of 1-Ethyl-3-methylimidazolium Thiocyanate Ionic Liquid with Catalytic Deactivated Compounds and Water at Several Temperatures: Experiments and Theoretical Predictions

    Directory of Open Access Journals (Sweden)

    Ramalingam Anantharaj

    2011-01-01

    Full Text Available Density, surface tension and refractive index were determined for the binary mixture of catalytic deactivated compounds with 1-ethyl-3-methylimidazolium thiocyanate {[EMIM][SCN]} at temperature of (298.15 to 323.15 K. For all the compounds with ILs, the densities varied linearly in the entire mole fraction with increasing temperature. From the obtained data, the excess molar volume and deviation of surface tension and refractive index have been calculated. A strong interaction was found between similar (cation-thiophene or cation-pyrrole compounds. The interaction of IL with dissimilar compounds such as indoline and quinoline and other multiple ring compounds was found to strongly depend on the composition of IL at any temperatures. For the mixtures, the surface tension decreases in the order of: thiophene > quinoline > pyridine > indoline > pyrrole > water. In general from the excess volume studies, the IL-sulphur/nitrogen mixture has stronger interaction as compared to IL-IL, thiophene-thiophene or pyrrole-pyrrole interaction. The deviation of surface tension was found to be inversely proportional to deviation of refractive index. The quantum chemical based COSMO-RS was used to predict the non-ideal liquid phase activity coefficient for all mixtures. It indicated an inverse relation between activity coefficient and excess molar volumes.

  8. An efficient route for catalytic activity promotion via hybrid electro-depositional modification on commercial nickel foam for hydrogen evolution reaction in alkaline water electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Guanshui; He, Yongwei; Wang, Mei; Zhu, Fuchun; Tang, Bin [Research Institute of Surface Engineering, Taiyuan University of Technology, Yingze West Road 79, Taiyuan 030024 (China); Wang, Xiaoguang, E-mail: wangxiaog1982@163.com [Research Institute of Surface Engineering, Taiyuan University of Technology, Yingze West Road 79, Taiyuan 030024 (China); International Iberian Nanotechnology Laboratory (INL), 4715-330 Braga (Portugal)

    2014-09-15

    Highlights: • Mono-Cu surface modification depress the HER activity of Ni-foam. • Hybrid Ni-foam/Cu0.01/Co0.05 exhibits superior HER performance. • Layer-by-layer structure may contribute to a synergistic promoting effect. - Abstract: In this paper, the single- and hybrid-layered Cu, Ni and Co thin films were electrochemically deposited onto the three-dimensional nickel foam as composite cathode catalyst for hydrogen evolution reaction in alkaline water electrolysis. The morphology, structure and chemical composition of the electrodeposited composite catalysts were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Electrochemical measurement depicted that, for the case of the monometallic layered samples, the general activity for hydrogen evolution reaction followed the sequence: Ni-foam/Ni > Ni-foam/Co > bare Ni-foam > Ni-foam/Cu. It is noteworthy that, the hybrid-layered Ni-foam/Cu0.01/Co0.05 exhibited the highest catalytic activity towards hydrogen evolution reaction with the current density as high as 2.82 times that of the bare Ni-foam. Moreover, both excellent electrochemical and physical stabilities can also be acquired on the Ni-foam/Cu0.01/Co0.05, making this hybrid-layered composite structure as a promising HER electro-catalyst.

  9. Peroxidase-like catalytic activity of water-insoluble complex linked Fe(III)-thiacalix[4]arenetetrasulfonate with tetrakis(1-methylpyridinium-4-yl)porphine via ionic interaction.

    Science.gov (United States)

    Odo, Junichi; Sumihiro, Manabu; Okadome, Takuma; Inoguchi, Masahiko; Akashi, Haruo; Nakagoe, Kazunori

    2009-12-01

    A new water-insoluble Fe(3+)-TCAS[4]/TMPyP complex linked tetraanionic Fe(III)-thiacalix[4]arenetetrasulfonate (Fe(3+)-TCAS[4]) with tetracationic tetrakis(1-methylpyridinium-4-yl)porphine (TMPyP) via ionic interaction was prepared. The peroxidase-like catalytic activity of the Fe(3+)-TCAS[4]/TMPyP complex was investigated based on the dye formation reaction by oxidation of 4-aminoantipyrine and phenol with H(2)O(2) catalyzed by peroxidase. This Fe(3+)-TCAS[4]/TMPyP complex showed the highest activity in pH 5.5 acetate buffer solutions, and it was applied to the photometric determination of trace amounts of H(2)O(2). The calibration curve was linear over the range from 1.0 to 35 microg of H(2)O(2) in a 1.0 ml sample solution. Moreover, the method using glucoseoxidase and the Fe(3+)-TCAS[4]/TMPyP complex was applied to the determination of glucose, and the results were satisfactory even in control sera. The Fe(3+)-TCAS[4]/TMPyP complex can be applied to a practical sample, such as blood or urine, as an analytical reagent for the photometric determination of H(2)O(2) in place of peroxidase.

  10. Catalytic Effect of Activated Carbon and Activated Carbon Fiber in Non-Equilibrium Plasma-Based Water Treatment

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yanzong; ZHENG Jingtang; QU Xianfeng; YU Weizhao; CHEN nonggang

    2008-01-01

    Catalysis and regeneration efficiency of granular activated carbon (GAC) and acti-vated carbon fiber (ACF) were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer discharge and GAC or ACF. The experimental results show that the degradation efficiency of methyl orange (MO) by the combined treatment can increase 22% (for GAC) and 24% (for ACF) respectively compared to pulsed discharge treatment alone, indicating that the combined treatment has a synergetic effect. The MO degradation efficiency by the combined treatment with pulsed discharge and saturated GAC or ACF can increase 12% and 17% respectively compared to pulsed discharge treatment alone. Both GAC and ACF show catalysis and the catalysis of ACF is prominent. Meanwhile, the regeneration of GAC and ACF are realized in this process. When H2O2 is introduced into the system, the utilization efficiency of ozone and ultraviolet light is improved and the regeneration efficiency of GAC and ACF is also increased.

  11. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts

    Directory of Open Access Journals (Sweden)

    Rodiansono Rodiansono

    2015-07-01

    Full Text Available A bulk structure of inexpensive intermetallic nickel-tin (Ni-Sn alloys catalysts demonstrated highly selective in the hydrogenation of levulinic acid in water into g-valerolactone. The intermetallic Ni-Sn catalysts were synthesized via a very simple thermochemical method from non-organometallic precursor at low temperature followed by hydrogen treatment at 673 K for 90 min. The molar ratio of nickel salt and tin salt was varied to obtain the corresponding Ni/Sn ratio of 4.0, 3.0, 2.0, 1.5, and 0.75. The formation of Ni-Sn alloy species was mainly depended on the composition and temperature of H2 treatment. Intermetallics Ni-Sn that contain Ni3Sn, Ni3Sn2, and Ni3Sn4 alloy phases are known to be effective heterogeneous catalysts for levulinic acid hydrogenation giving very excellence g-valerolactone yield of >99% at 433 K, initial H2 pressure of 4.0 MPa within 6 h. The effective hydrogenation was obtained in H2O without the formation of by-product. Intermetallic Ni-Sn(1.5 that contains Ni3Sn2 alloy species demonstrated very stable and reusable catalyst without any significant loss of its selectivity. © 2015 BCREC UNDIP. All rights reserved. Received: 26th February 2015; Revised: 16th April 2015; Accepted: 22nd April 2015  How to Cite: Rodiansono, R., Astuti, M.D., Ghofur, A., Sembiring, K.C. (2015. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (2: 192-200. (doi:10.9767/bcrec.10.2.8284.192-200Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.2.8284.192-200  

  12. Catalytic supercritical water gasification of primary paper sludge using a homogeneous and heterogeneous catalyst: Experimental vs thermodynamic equilibrium results.

    Science.gov (United States)

    Louw, Jeanne; Schwarz, Cara E; Burger, Andries J

    2016-02-01

    H2, CH4, CO and CO2 yields were measured during supercritical water gasification (SCWG) of primary paper waste sludge (PWS) at 450°C. Comparing these yields with calculated thermodynamic equilibrium values offer an improved understanding of conditions required to produce near-equilibrium yields. Experiments were conducted at different catalyst loads (0-1g/gPWS) and different reaction times (15-120min) in a batch reactor, using either K2CO3 or Ni/Al2O3-SiO2 as catalyst. K2CO3 up to 1g/gPWS increased the H2 yield significantly to 7.5mol/kgPWS. However, these yields and composition were far from equilibrium values, with carbon efficiency (CE) and energy recovery (ER) of only 29% and 20%, respectively. Addition of 0.5-1g/gPWS Ni/Al2O3-SiO2 resulted in high H2 and CH4 yields (6.8 and 14.8mol/kgPWS), CE of 84-90%, ER of 83% and a gas composition relatively close to the equilibrium values (at hold times of 60-120min).

  13. Paradoxical co-existing base metal sulphides in the mantle: The multi-event record preserved in Loch Roag peridotite xenoliths, North Atlantic Craton

    Science.gov (United States)

    Hughes, Hannah S. R.; McDonald, Iain; Loocke, Matthew; Butler, Ian B.; Upton, Brian G. J.; Faithfull, John W.

    2017-04-01

    The role of the subcontinental lithospheric mantle as a source of precious metals for mafic magmas is contentious and, given the chalcophile (and siderophile) character of metals such as the platinum-group elements (PGE), Se, Te, Re, Cu and Au, the mobility of these metals is intimately linked with that of sulphur. Hence the nature of the host phase(s), and their age and stability in the subcontinental lithospheric mantle may be of critical importance. We investigate the sulphide mineralogy and sulphide in situ trace element compositions in base metal sulphides (BMS) in a suite of spinel lherzolite mantle xenoliths from northwest Scotland (Loch Roag, Isle of Lewis). This area is situated on the margin of the North Atlantic Craton which has been overprinted by a Palaeoproterozoic orogenic belt, and occurs in a region which has undergone magmatic events from the Palaeoproterozoic to the Eocene. We identify two populations of co-existing BMS within a single spinel lherzolite xenolith (LR80) and which can also be recognised in the peridotite xenolith suite as a whole. Both populations consist of a mixture of Fe-Ni-Cu sulphide minerals, and we distinguished between these according to BMS texture, petrographic setting (i.e., location within the xenolith in terms of 'interstitial' or within feldspar-spinel symplectites, as demonstrated by X-ray Computed Microtomography) and in situ trace element composition. Group A BMS are coarse, metasomatic, have low concentrations of total PGE (entrainment). Based on the cross-cutting relationships of the symplectites, it is possible to infer the relative ages of each metasomatic BMS population. We tally these with major tectono-magmatic events for the North Atlantic region by making comparisons to carbonatite events recorded in crustal and mantle rocks, and we suggest that the Pt-enrichment was associated with a pre-Carboniferous carbonatite episode. This method of mantle xenolith base metal sulphide documentation may ultimately

  14. Connections between 5-HT-containing terminals and 5-HT2A receptor and γ-aminobutyric acid or glycine co-existed neurons in the rat medullary dorsal horn

    Institute of Scientific and Technical Information of China (English)

    LI Hui; LI Yun-qing

    2001-01-01

    Objective: To investigate the connections between serotonin (5-HT)-containing terminals and 5-HT2A receptor (5-HT2AR)/γ-aminobutyric acid (GABA) or 5-HT2AR/glycine co-existed neurons in the rat medullary dorsal horn (MDH).Methods: Immunofluorescence histochemical triple-staining for 5-HT, 5-HT2AR, GABA or glycine. Results: 5-HT-immunoreaetive fibers and terminals were chiefly located in the superficial laminae (laminae Ⅰ and Ⅱ) of the MDH. Neurons exhibiting 5-HT2AR-, GABA- or glycine-immunoreactivities were mainly observed in the superficial laminae. Some 5-HT2AR-immunopositive neurons also exhibited GABA- or glycine-immunoreaetivities. 5-HT-containing terminals made close contacts with 5-HT2AR/GABA or 5-HT2AR/glycine co-existed neurons. Conclusion: 5-HT2AR/GABA or 5-HT2AR /glycine co-exist in some of the neurons in the superficial laminae of the MDH. 5-HT-immunoreactive terminals form close connections with 5-HT2AR/GABA or 5-HT2AR/glycine co-existed neurons.

  15. Method of Analysis by the U.S. Geological Survey California District Sacramento Laboratory-- Determination of Dissolved Organic Carbon in Water by High Temperature Catalytic Oxidation, Method Validation, and Quality-Control Practices

    Science.gov (United States)

    Bird, Susan M.; Fram, Miranda S.; Crepeau, Kathryn L.

    2003-01-01

    An analytical method has been developed for the determination of dissolved organic carbon concentration in water samples. This method includes the results of the tests used to validate the method and the quality-control practices used for dissolved organic carbon analysis. Prior to analysis, water samples are filtered to remove suspended particulate matter. A Shimadzu TOC-5000A Total Organic Carbon Analyzer in the nonpurgeable organic carbon mode is used to analyze the samples by high temperature catalytic oxidation. The analysis usually is completed within 48 hours of sample collection. The laboratory reporting level is 0.22 milligrams per liter.

  16. Enhanced methane and hydrogen yields from catalytic supercritical water gasification of pine wood sawdust via pre-processing in subcritical water

    OpenAIRE

    Onwudili, JA; Williams, PT

    2013-01-01

    A two-stage batch hydrothermal process has been investigated with the aim of enhancing the yields of hydrogen and methane from sawdust. Samples of the sawdust were rapidly treated in subcritical water and with added Na2CO3 (alkaline compound) and Nb2O3 (solid acid) at 280 °C, 8 MPa. Each pre-processing route resulted in a solid recovered product (SRP), an aqueous residue and a small amount of gas composed mainly of CO2. In the second stage, the SRP and the liquid residues were gasified in sup...

  17. New self-assembled material based on Ru nanoparticles and 4-sulfocalix[4]arene as an efficient and recyclable catalyst for reduction of brilliant yellow azo dye in water: a new model catalytic reaction

    Science.gov (United States)

    Rambabu, Darsi; Pradeep, Chullikkattil P.; Dhir, Abhimanew

    2016-12-01

    New self-assembled material ( Ru@SC) with ruthenium nanoparticles (Ru NPs) and 4-sulfocalix[4]arene (SC) is synthesized in water at room temperature. Ru@SC is characterized by thermal gravimetric analysis, FT-IR, powder x-ray diffraction, TEM and SEM analysis. The size of Ru nanoparticles in the self-assembly is approximately 5 nm. The self-assembled material Ru@SC shows an efficient catalytic reduction of toxic `brilliant yellow' (BY) azo dye. The reduced amine products were successfully separated and confirmed by single-crystal XRD, NMR and UV-Vis spectroscopy. Ru@SC showed a better catalytic activity in comparison with commercial catalysts Ru/C (ruthenium on charcoal 5 %) and Pd/C (palladium on charcoal 5 and 10 %). The catalyst also showed a promising recyclability and heterogeneous nature as a catalyst for reduction of `BY' azo dye.

  18. Impact of water quality on removal of carbamazepine in natural waters by N-doped TiO{sub 2} photo-catalytic thin film surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Avisar, Dror, E-mail: drorvi@post.tau.ac.il [The Hydro-Chemistry Laboratory, Faculty of Geography and the Environment, Tel Aviv University, Tel Aviv 69978 (Israel); Horovitz, Inna [The Hydro-Chemistry Laboratory, Faculty of Geography and the Environment, Tel Aviv University, Tel Aviv 69978 (Israel); School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Lozzi, Luca; Ruggieri, Fabrizio [Department of Physical and Chemical Sciences, University of L’Aquila, Via Vetoio, I-67010 Coppito, L’Aquila (Italy); Baker, Mark; Abel, Marie-Laure [The Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Mamane, Hadas [School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel)

    2013-01-15

    Highlights: ► N-doped TiO{sub 2} thin films have been deposited by sol–gel dip-coating. ► CBZ removal improved with increasing medium pH in the range of 5–9. ► DOC at a concentration of 5 mg/L resulted in an ∼20% reduction in CBZ removal. ► Alkalinity values of 100 mg/L as CaCO{sub 3} resulted in a 40% decrease in CBZ removal. ► Complete suppression of the photocatalytic process in wastewater effluent. -- Abstract: Photocatalytic experiments on the pharmaceutical pollutant carbamazepine (CBZ) were conducted using sol–gel nitrogen-doped TiO{sub 2}-coated glass slides under a solar simulator. CBZ was stable to photodegradation under direct solar irradiation. No CBZ sorption to the catalyst surface was observed, as further confirmed by surface characterization using X-ray photoelectron spectroscopic analysis of N-doped TiO{sub 2} surfaces. When exposing the catalyst surface to natural organic matter (NOM), an excess amount of carbon was detected relative to controls, which is consistent with NOM remaining on the catalyst surface. The catalyst surface charge was negative at pH values from 4 to 10 and decreased with increasing pH, correlated with enhanced CBZ removal with increasing medium pH in the range of 5–9. A dissolved organic carbon concentration of 5 mg/L resulted in ∼20% reduction in CBZ removal, probably due to competitive inhibition of the photocatalytic degradation of CBZ. At alkalinity values corresponding to CaCO{sub 3} addition at 100 mg/L, an over 40% decrease in CBZ removal was observed. A 35% reduction in CBZ occurred in the presence of surface water compared to complete suppression of the photocatalytic process in wastewater effluent.

  19. Catalytic hydrodechlorination of trichloroethylene in a novel NaOH/2-propanol/methanol/water system on ceria-supported Pd and Rh catalysts.

    Science.gov (United States)

    Cobo, Martha; Becerra, Jorge; Castelblanco, Miguel; Cifuentes, Bernay; Conesa, Juan A

    2015-08-01

    The catalytic hydrodechlorination (HDC) of high concentrations of trichloroethylene (TCE) (4.9 mol%, 11.6 vol%) was studied over 1%Pd, 1%Rh and 0.5%Pd-0.5%Rh catalysts supported on CeO2 under conditions of room temperature and pressure. For this, a one-phase system of NaOH/2-propanol/methanol/water was designed with molar percentages of 13.2/17.5/36.9/27.6, respectively. In this system, the alcohols delivered the hydrogen required for the reaction through in-situ dehydrogenation reactions. PdRh/CeO2 was the most active catalyst for the degradation of TCE among the evaluated materials, degrading 85% of the trichloroethylene, with alcohol dehydrogenation rates of 89% for 2-propanol and 83% for methanol after 1 h of reaction. Fresh and used catalysts were characterized by Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and Thermogravimetric analysis (TGA). These results showed important differences of the active phase in each catalyst sample. Rh/CeO2 had particle sizes smaller than 1 nm and the active metal was partially oxidized (Rh(0)/Rh(+δ) ratio of 0.43). This configuration showed to be suitable for alcohols dehydrogenation. On the contrary, Pd/CeO2 showed a Pd completed oxidized and with a mean particle size of 1.7 nm, which seemed to be unfavorable for both, alcohols dehydrogenation and TCE HDC. On PdRh/CeO2, active metals presented a mean particle size of 2.7 nm and more reduced metallic species, with ratios of Rh(0)/Rh(+δ) = 0.67 and Pd(0)/Pd(+δ) = 0.28, which showed to be suitable features for the TCE HDC. On the other hand, TGA results suggested some deposition of NaCl residues over the catalyst surfaces. Thus, the new reaction system using PdRh/CeO2 allowed for the degradation of high concentrations of the chlorinated compound by using in situ hydrogen liquid donors in a reaction at room temperature and pressure.

  20. Preparation of Pt/K2La2Ti3O10 and its photo-catalytic activity for hydrogen evolution from methanol water solution

    Institute of Scientific and Technical Information of China (English)

    CUI; Wenquan

    2006-01-01

    ):A new series of layered perovskites exhibiting ion exchange,Inorg.Chem.,1987,26:4299-4301.[12]Takata,T.,Shinohara,K.,Tanaka,A.,Hara,M.,Kondo,J.N.,Domen,K.,A highly active photocatalyst for overall water splitting with a hydrated layered perovskite structure,J.Photochem.Photobiol.A:Chem.,1997,106(1-3):45-49.[13]Cui,W.Q.,Feng,L.R.,Xu,C.H.,Lü,S.J.,Qiu,F.L.,Hydrogen production by photocatalytic decomposition of methanol gas on Pt/TiO2 nano-film,Catal.Comm.,2004(5):533-536.[14]Herrmann,J.M.,Disdier,J.,Pichat,P.,Photoassisted platinum deposition on TiO2 powder using various platinum complexes,J.Phys.Chem.,1986,90:6028-6034.[15]Cui,W.Q.,Feng,L.R.,Xu,C.H.,Lü,S.J.,Qiu,F.L.,Studies on the photo-catalytic decomposition of methanol vapor on Pt-loaded nano-TiO2 particles,Acta Chim.Sinica (in Chinese),2005,63(3):203-209.[16]Ikeda,S.,Hara,M.,Kondo,J.N.,Domen,K.,Preparation of K2La2Ti3O10 by polymerized complex method and photocatalytic decomposition of water,Chem.Mater.,1998,10(1):72-77.[17]Yang,X.Y.,Per,Z.F.,Bai,R.Q.,Studies on dispersion of Pt by HOT,Petrochemical Technology,1978,7(4):352.[18]Fox,M.A.,Dulay,M.Y.,Heterogeneous photocatalysis,Chem.Rev.,1993,93(1):341-357.[19]Kudo,A.,Sakata,T.,Luminescent properties of nondoped and rare earth metal ion-doped K2La2Ti3O10 with layered perovskite structures:Importance of the hole trap process,J.Phys.Chem.,1995,99:15963-15967.

  1. Application of catalytic combustion technology in the treatment of foul gas from refinery waste water treatment plant%催化燃烧技术在炼油污水处理场恶臭治理中的应用

    Institute of Scientific and Technical Information of China (English)

    刘永斌; 程俊梅; 程彬彬

    2011-01-01

    介绍了催化燃烧技术在炼油污水处理场恶臭治理中的应用情况.工业应用表明,催化燃烧技术适用于处理石化炼油污水场总进水口、隔油池、浮选池等散发的恶臭气体,废气处理效果良好.恶臭治理设施运行后,对硫化物的去除率达95%以上,对硫化氢的去除率接近100%,对总烃的去除率达到85%以上,净化后的气体能够满足国家排放标准的要求.催化燃烧技术治理恶臭污染项目的实施,对同类型炼化装置将起到借鉴作用.%The application of catalytic combustion technology in the treatment of foul gas from refinery waste water treatment plant was introduced. The catalytic combustion technology was applicable for the treatment of foul gases from water inlet of refinery waste water treatment plant, API separator, flotation pit, etc with good results. After operation of foul gas treatment facilities, the sulfide removal rate is over 95% , the H2S removal rate is close to 100% and total hydrocarbons removal rate is more than 85%. The purified gas meets China national emission standards. The implementation of foul gas treatment facilities using catalytic combustion technology provides a good reference for the operation of similar refinery process units.

  2. Diurnal and Seasonal Changes in Stem Radius Increment and Sap Flow Density Indicate Different Responses of Two Co-existing Oak Species to Drought Stress

    Directory of Open Access Journals (Sweden)

    MÉSZÁROS, Ilona

    2011-01-01

    Full Text Available Using continuous monitoring of stem radius combined with sap flow measurements weassessed the effects of environmental conditions on tree radial growth and water status of two coexistingoak species (Quercus petraea and Quercus cerris at high resolution time in growingseasons of 2008 and 2009. The forest (95–100 yr is situated in a xeric site in the transition zonebetween forested and forest-steppe regions in north-eastern Hungary, Bükk mountains (47o90’N,20o46’E, elevation 320–340 m a.s.l.. Weather conditions in the growing season of 2008 (totalrainfall 354 mm, mean daily temperature 17.0 oC was less extreme than in 2009 (total rainfall299 mm, temperature 17.9 oC. Rainfall strongly determined the course of radial growth incrementin trees. Radial growth of trees was limited in 2009 due to the drought in spring. The maximumradial increment of both species was achieved three weeks earlier (4th week of June than in 2008(4th week of July. We used dendrometer monitoring data for estimation of stem (tree waterdeficit (W by measuring water-related changes in stem radius (Zweifel et al. 2005. Themagnitude of tree water deficit variation (W was always smaller in Q. cerris than in Q. petraea.In contrast, Quercus cerris always exhibited larger daytime averages and maxima of sap flowdensity. In August of 2009 when drought became severe there were larger increases in tree waterdeficit (W (50–55 % in both species compared to July as it could be expected from the extentof decreases in sap flow density (24–28%. Our data suggested that due to the low SWC thetranspiration was supported mainly from the inner water storage of trees during prolonged droughtwhich resulted in high stem water deficit (W.

  3. Clinical study of partial mole or choriocarcinoma with co-existing fetus%妊娠合并部分性葡萄胎或绒癌临床研究

    Institute of Scientific and Technical Information of China (English)

    赵湘婉; 李娟清

    2010-01-01

    目的 通过对妊娠合并部分性葡萄胎或绒癌病例的报道和分析,以引起临床重视.方法 回顾性分析妊娠合并部分性葡萄胎或绒癌7例的临床资料及相关辅助检查(β-hCG检测和超声),7例患者年龄平均28岁.所有病例均经手术和病理予以确诊.结果 妊娠合并部分性葡萄胎共5例,母均存活,胎儿仅存活1例,为孕32周者;妊娠合并绒癌者共2例,母均死亡,婴儿1例死亡,1例存活,2年后失访.结论 近年本类疾病有增多趋势,应引起遗传学、生殖医学、妇科肿瘤、围产医学和病理学等重视.%Objective To evaluate the rare entity of partial mole or choriocarcinoma with co-existing fetus.Methods A total of 7 cases of partial mole or choriocarcinoma with co-existing fetus were selected to collect clinical profiles and perform auxiliary examinations such as serum β-hCG and sonography.The data were analyzed retrospectively and all cases confirmed by surgery and histopathological diagnosis.Results There were 5 cases of partial moles with co-existing fetus.All patients stayed alive at follow-up.However,only 1 fetus delivered at 32-week gestation survived.All patients of choriocarcinoma with co-existing fetus died.Among them,1 newborn died and another one lost follow-up after 2 years.Conclusion Recently the rate of gestational trophoblastic disease with co-existing fetus is rising.It is quite important that the professionals of genetics,reproductive medicine,gynecological oncology,perinatal medicine and pathology should pay more attention to this emerging disease.

  4. 石化厂污水反渗透浓水的催化臭氧氧化处理%Catalytic Ozonation Treatment of Reverse Osmosis-concentrated Water from Petrochemical Plant Wastewater

    Institute of Scientific and Technical Information of China (English)

    龚小芝; 赵辉; 万国晖; 刘正; 栾金义

    2012-01-01

    针对某炼油厂二沉池出水回用过程中产生的反渗透浓水高盐、高硬、低COD和可生化性差的特点,采用催化臭氧氧化工艺处理,出水达标排放.实验确定了对臭氧氧化催化效果最好的催化剂,合适的反应条件为:反应时间大于30 min,臭氧质量浓度15-30 mg/L.经催化臭氧氧化处理后,反渗透浓水的COD降低至60 mg/L以下,满足排放要求,同时反渗透浓水可生化性提高.%Based on the characteristics of high salt content, high hardness, low COD and bad biodegradability, the reverse osmosis-concentrated water produced in the reuse of wastewater from the secondary sedimentation tank in a refinery was treated by catalytic ozonation process, and the effluent can meet the discharge standards. The best catalyst for catalytic ozonation is confirmed through experiments and the optimum reaction conditions are as follows: reaction time more than 30 min, ozone mass concentration 15-30 mg/L. After treated by catalytic ozonation, the COD of the reverse osmosis- concentrated water is decreased to below 60 mg/L, which can meet the discharge standards. At the same time, the biodegradability of the treated wastewater is improved.

  5. Catalytic combustor for hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Mercea, J.; Grecu, E.; Fodor, T.; Kreibik, S.

    1982-01-01

    The performance of catalytic combustors for hydrogen using platinum-supported catalysts is described. Catalytic plates of different sizes were constructed using fibrous and ceramic supports. The temperature distribution as well as the reaction efficiency as a function of the fuel input rate was determined, and a comparison between the performances of different plates is discussed.

  6. Catalytic gasification of biomass

    Science.gov (United States)

    Robertus, R. J.; Mudge, L. K.; Sealock, L. J., Jr.; Mitchell, D. H.; Weber, S. L.

    1981-12-01

    Methane and methanol synthesis gas can be produced by steam gasification of biomass in the presence of appropriate catalysts. This concept is to use catalysts in a fluidized bed reactor which is heated indirectly. The objective is to determine the technical and economic feasibility of the concept. Technically the concept has been demonstrated on a 50 lb per hr scale. Potential advantages over conventional processes include: no oxygen plant is needed, little tar is produced so gas and water treatment are simplified, and yields and efficiencies are greater than obtained by conventional gasification. Economic studies for a plant processing 2000 T/per day dry wood show that the cost of methanol from wood by catalytic gasification is competitive with the current price of methanol. Similar studies show the cost of methane from wood is competitive with projected future costs of synthetic natural gas. When the plant capacity is decreased to 200 T per day dry wood, neither product is very attractive in today's market.

  7. Mutation in the S gene of hepatitis B virus and anti-HBs subtype-nonspecificity contributed to the co-existence of HBsAg and anti-HBs in patients with chronic hepatitis B virus infection.

    Science.gov (United States)

    Fu, Xiaochun; Chen, Jing; Chen, Huijuan; Lin, Jinpiao; Xun, Zhen; Li, Shiqi; Liu, Can; Zeng, Yongbin; Chen, Tianbin; Yang, Bin; Ou, Qishui

    2017-02-15

    The mechanism for the co-existence of hepatitis B surface antigen (HBsAg) and antibodies to HBsAg (anti-HBs) in chronic HBV infected patients remains controversial. This study aimed to explore the role of HBV S gene mutation and anti-HBs subtype-nonspecificity in patients with simultaneous HBsAg/anti-HBs positivity. Chronic HBV infections with (n = 145, group I) and without (n = 141, group II) anti-HBs were included. The S gene was amplified and sequenced. The neutralization experiment was used in group I patients' sera to determine the specificity of anti-HBs. Additionally, the HBV vaccinated persons' sera were used to estimate the neutralize capacity of anti-HBs against HBsAg in group I patients. Results showed that 2.63% (145/5513) chronic HBV infected patients had positive results for anti-HBs. HBsAg amino acid (aa) substitution rate in 35 patients of group I was significantly higher than that in 58 patients of group II (1.89% vs 0.95%, P anti-HBs in (74.29%, 26/35) patients was not directed to the subtypes of the co-existing HBsAg. Besides, some HBsAg variations in group I patients, sG145R mutation, inserted mutations, and continuous aa mutations within the major hydrophilic region (MHR), decreased the neutralized capacity of anti-HBs from HBV vaccinated persons. In conclusion, both of HBsAg mutation and anti-HBs subtype-nonspecificity contributed to the co-existence of HBsAg and anti-HBs in chronic HBV infection. HBV vaccine recipients may still have a risk of HBV infection when exposure to patients with simultaneous HBsAg/anti-HBs positivity.

  8. Light-toned salty soils and co-existing Si-rich species discovered by the Mars Exploration Rover Spirit in Columbia Hills

    Science.gov (United States)

    Wang, Alian; Bell, J.F.; Li, Ron; Johnson, J. R.; Farrand, W. H.; Cloutis, E.A.; Arvidson, R. E.; Crumpler, L.; Squyres, S. W.; McLennan, S.M.; Herkenhoff, K. E.; Ruff, S.W.; Knudson, A.T.; Chen, Wei; Greenberger, R.

    2008-01-01

    Light-toned soils were exposed, through serendipitous excavations by Spirit Rover wheels, at eight locations in the Columbia Hills. Their occurrences were grouped into four types on the basis of geomorphic settings. At three major exposures, the light-toned soils are hydrous and sulfate-rich. The spatial distributions of distinct types of salty soils vary substantially: with centimeter-scaled heterogeneities at Paso Robles, Dead Sea, Shredded, and Champagne-Penny, a well-mixed nature for light-toned soils occurring near and at the summit of Husband Hill, and relatively homogeneous distributions in the two layers at the Tyrone site. Aeolian, fumarolic, and hydrothermal fluid processes are suggested to be responsible for the deposition, transportation, and accumulation of these light-toned soils. In addition, a change in Pancam spectra of Tyrone yellowish soils was observed after being exposed to current Martian surface conditions for 175 sols. This change is interpreted to be caused by the dehydration of ferric sulfates on the basis of laboratory simulations and suggests a relative humidity gradient beneath the surface. Si-rich nodules and soils were observed near the major exposures of S-rich soils. They possess a characteristic feature in Pancam visible near-infrared (Vis-NIR) spectra that may be diagnostic of hydrated species, and this spectral feature can be used to search for additional Si-rich species. The exposures of hydrated salty soils within various geomorphic settings imply the potential existence of hydrous minerals in similar settings over a much wider area. Hydrous sulfates represent one of the candidates that may contribute the high level of water equivalent hydrogen in equatorial regions detected by the Neutron Spectrometer on Mars Odyssey.

  9. Catalytic Functions of Standards

    NARCIS (Netherlands)

    K. Blind (Knut)

    2009-01-01

    textabstractThe three different areas and the examples have illustrated several catalytic functions of standards for innovation. First, the standardisation process reduces the time to market of inventions, research results and innovative technologies. Second, standards themselves promote the diffusi

  10. Catalytic Synthesis Lactobionic Acid

    Directory of Open Access Journals (Sweden)

    V.G. Borodina

    2014-07-01

    Full Text Available Gold nanoparticles are obtained, characterized and deposited on the carrier. Conducted catalytic synthesis of lactobionic acid from lactose. Received lactobionic acid identify on the IR spectrum.

  11. Catalytic distillation process

    Science.gov (United States)

    Smith, Jr., Lawrence A.

    1982-01-01

    A method for conducting chemical reactions and fractionation of the reaction mixture comprising feeding reactants to a distillation column reactor into a feed zone and concurrently contacting the reactants with a fixed bed catalytic packing to concurrently carry out the reaction and fractionate the reaction mixture. For example, a method for preparing methyl tertiary butyl ether in high purity from a mixed feed stream of isobutene and normal butene comprising feeding the mixed feed stream to a distillation column reactor into a feed zone at the lower end of a distillation reaction zone, and methanol into the upper end of said distillation reaction zone, which is packed with a properly supported cationic ion exchange resin, contacting the C.sub.4 feed and methanol with the catalytic distillation packing to react methanol and isobutene, and concurrently fractionating the ether from the column below the catalytic zone and removing normal butene overhead above the catalytic zone.

  12. Catalytic distillation process

    Science.gov (United States)

    Smith, L.A. Jr.

    1982-06-22

    A method is described for conducting chemical reactions and fractionation of the reaction mixture comprising feeding reactants to a distillation column reactor into a feed zone and concurrently contacting the reactants with a fixed bed catalytic packing to concurrently carry out the reaction and fractionate the reaction mixture. For example, a method for preparing methyl tertiary butyl ether in high purity from a mixed feed stream of isobutene and normal butene comprising feeding the mixed feed stream to a distillation column reactor into a feed zone at the lower end of a distillation reaction zone, and methanol into the upper end of said distillation reaction zone, which is packed with a properly supported cationic ion exchange resin, contacting the C[sub 4] feed and methanol with the catalytic distillation packing to react methanol and isobutene, and concurrently fractionating the ether from the column below the catalytic zone and removing normal butene overhead above the catalytic zone.

  13. Catalytic distillation structure

    Science.gov (United States)

    Smith, L.A. Jr.

    1984-04-17

    Catalytic distillation structure is described for use in reaction distillation columns, and provides reaction sites and distillation structure consisting of a catalyst component and a resilient component intimately associated therewith. The resilient component has at least about 70 volume % open space and is present with the catalyst component in an amount such that the catalytic distillation structure consists of at least 10 volume % open space. 10 figs.

  14. Catalytic processes for space station waste conversion

    Science.gov (United States)

    Schoonover, M. W.; Madsen, R. A.

    1986-01-01

    Catalytic techniques for processing waste products onboard space vehicles were evaluated. The goal of the study was the conversion of waste to carbon, wash water, oxygen and nitrogen. However, the ultimate goal is conversion to plant nutrients and other materials useful in closure of an ecological life support system for extended planetary missions. The resulting process studied involves hydrolysis at 250 C and 600 psia to break down and compact cellulose material, distillation at 100 C to remove water, coking at 450 C and atmospheric pressure, and catalytic oxidation at 450 to 600 C and atmospheric pressure. Tests were conducted with a model waste to characterize the hydrolysis and coking processes. An oxidizer reactor was sized based on automotive catalytic conversion experience. Products obtained from the hydrolysis and coking steps included a solid residue, gases, water condensate streams, and a volatile coker oil. Based on the data obtained, sufficient component sizing was performed to make a preliminary comparison of the catalytic technique with oxidation for processing waste for a six-man spacecraft. Wet oxidation seems to be the preferred technique from the standpoint of both component simplicity and power consumption.

  15. Dynamics of co-existing Escherichia colilineages in situ of the infant gut and multiplex phenotypic targeted recovery of previously uncultivated bacteria from the human gut

    DEFF Research Database (Denmark)

    Gumpert, Heidi

    documented case wheretransfer of resistance genes was observed in situ of a non-perturbed gut in the absenceof antibiotic treatment. Additionally, cases of genomic deletions, phage infections andcuring, and plasmid loss were observed, highlighting that strains in the gut are highly dynamic. The detection...... were selected due to an observed change in their antibiotic susceptibility profile. Via full genome sequencing, we identified that in both cases a conjugative plasmid harboring antibiotic resistance genes was transferred between co-existing E. coli lineages and is responsible for the change...... in antibiotic susceptibility. In one case, the transfer occurred in the absenceof antibiotic treatment and the transconjugant remained amongst the gut microbiota for months, providing evidence to the hypothesis that resistance genes are stably maintained once acquired. To our knowledge, this is the first...

  16. Catalytic hydrotreating process

    Science.gov (United States)

    Karr, Jr., Clarence; McCaskill, Kenneth B.

    1978-01-01

    Carbonaceous liquids boiling above about 300.degree. C such as tars, petroleum residuals, shale oils and coal-derived liquids are catalytically hydrotreated by introducing the carbonaceous liquid into a reaction zone at a temperature in the range of 300.degree. to 450.degree. C and a pressure in the range of 300 to 4000 psig for effecting contact between the carbonaceous liquid and a catalytic transition metal sulfide in the reaction zone as a layer on a hydrogen permeable transition metal substrate and then introducing hydrogen into the reaction zone by diffusing the hydrogen through the substrate to effect the hydrogenation of the carbonaceous liquid in the presence of the catalytic sulfide layer.

  17. Characterization of N-acylhomoserine lactone-degrading bacteria associated with the Zingiber officinale (ginger rhizosphere: Co-existence of quorum quenching and quorum sensing in Acinetobacter and Burkholderia

    Directory of Open Access Journals (Sweden)

    Chhabra Siri

    2011-03-01

    Full Text Available Abstract Background Cell-to-cell communication (quorum sensing (QS co-ordinates bacterial behaviour at a population level. Consequently the behaviour of a natural multi-species community is likely to depend at least in part on co-existing QS and quorum quenching (QQ activities. Here we sought to discover novel N-acylhomoserine lactone (AHL-dependent QS and QQ strains by investigating a bacterial community associated with the rhizosphere of ginger (Zingiber officinale growing in the Malaysian rainforest. Results By using a basal growth medium containing N-(3-oxohexanoylhomoserine lactone (3-oxo-C6-HSL as the sole source of carbon and nitrogen, the ginger rhizosphere associated bacteria were enriched for strains with AHL-degrading capabilities. Three isolates belonging to the genera Acinetobacter (GG2, Burkholderia (GG4 and Klebsiella (Se14 were identified and selected for further study. Strains GG2 and Se14 exhibited the broadest spectrum of AHL-degrading activities via lactonolysis while GG4 reduced 3-oxo-AHLs to the corresponding 3-hydroxy compounds. In GG2 and GG4, QQ was found to co-exist with AHL-dependent QS and GG2 was shown to inactivate both self-generated and exogenously supplied AHLs. GG2, GG4 and Se14 were each able to attenuate virulence factor production in both human and plant pathogens. Conclusions Collectively our data show that ginger rhizosphere bacteria which make and degrade a wide range of AHLs are likely to play a collective role in determining the QS-dependent phenotype of a polymicrobial community.

  18. 高级催化氧化法去除水中邻苯二甲酸酯的研究进展%Removal of phthalic acid esters from water by advanced catalytic oxidation process

    Institute of Scientific and Technical Information of China (English)

    刘静; 李亚茹; 王杰; 陈凯凯

    2014-01-01

    Generally, phthalic acid esters(PAEs) are considered to be endocrine disrupting chemicals (EDCs). This substance is widely used in plasticizers, cosmetics, etc. PAEs would give rise to malformation, cancerization and mutation as well as possess quasi/anti-estrogen activity and quasi/resistance-thyroid hormone activity. PAEs could spread to the environment easily and be detected in the soil, air and water. They are common pollutants in the environment, which pose serious threats to both human health and the ecological environment. As a result, PAEs have attracted widespread attention at home and abroad. This paper summarizes the physi-chemical properties and toxic effects of PAEs and analyses the pollution status in natural water, groundwater and wastewater. The work also discusses many recent methods developed to remove PAEs, such as enhanced coagulation, adsorption, membrane treatment, biological treatment, advanced oxidation process, etc. Advanced oxidation technology has attracted much attention and developed rapidly because of it’s ability to remove different kinds of organic pollutants quickly and efficiently from drinking water and sewage. This article introduces the degradation of PAEs in water mainly using advanced oxidation technology which includes the catalytic wet peroxide oxidation, the catalytic ozone oxidation, photocatalytic oxidation, ultrasonic and microwave assisted catalytic oxidation and advanced nanometer catalytic oxidation. Fenton catalytic oxidation process could produce highly reactive hydroxyl radicals by adding catalyst and UVradiation in the process of oxidation. This method could achieve the highest oxidation efficiency as well as degrade PAEs into non-toxic harmless chemicals completely and non-selectively. Although application of the catalyst in advanced oxidation process can improve the oxidation efficiency and the degradation degree greatly, this method needs a huge amount of catalyst and energy and also influenced by pH value

  19. Role of the chemically non-innocent ligand in the catalytic formation of hydrogen and carbon dioxide from methanol and water with the metal as the spectator.

    Science.gov (United States)

    Li, Haixia; Hall, Michael B

    2015-09-30

    The catalytic mechanism for the production of H2 and CO2 from CH3OH and H2O by [K(dme)2][Ru(H) (trop2dad)] (K(dme)2.1_exp) was investigated by density functional theory (DFT) calculations. Since the reaction occurs under mild conditions and at reasonable rates, it could be considered an ideal way to use methanol to store hydrogen. The predicted mechanism begins with the dehydrogenation of methanol to formaldehyde through a new ligand-ligand bifunctional mechanism, where two hydrogen atoms of CH3OH eliminate to the ligand's N and C atoms, a mechanism that is more favorable than the previously known mechanisms, β-H elimination, or the metal-ligand bifunctional. The key initiator of this first step is formed by migration of the hydride in 1 from the ruthenium to the meta-carbon atom, which generates 1″ with a frustrated Lewis pair in the ring between N and C. Hydroxide, formed when 1″ cleaves H2O, reacts rapidly with CH2O to give H2C(OH)O(-), which subsequently donates a hydride to 6 to generate HCOOH and 5. HCOOH then protonates 5 to give formate and a neutral complex, 4, with a fully hydrogenated ligand. The hydride of formate transfers to 6, releasing CO2. The fully hydrogenated complex, 4, is first deprotonated by OH(-) to form 5, which then releases hydrogen to regenerate the catalyst, 1″. In this mechanism, which explains the experimental observations, the whole reaction occurs on the chemically non-innocent ligand with the ruthenium atom appearing as a spectator.

  20. Catalytic efficiency of designed catalytic proteins.

    Science.gov (United States)

    Korendovych, Ivan V; DeGrado, William F

    2014-08-01

    The de novo design of catalysts that mimic the affinity and specificity of natural enzymes remains one of the Holy Grails of chemistry. Despite decades of concerted effort we are still unable to design catalysts as efficient as enzymes. Here we critically evaluate approaches to (re)design of novel catalytic function in proteins using two test cases: Kemp elimination and ester hydrolysis. We show that the degree of success thus far has been modest when the rate enhancements seen for the designed proteins are compared with the rate enhancements by small molecule catalysts in solvents with properties similar to the active site. Nevertheless, there are reasons for optimism: the design methods are ever improving and the resulting catalyst can be efficiently improved using directed evolution.

  1. Catalytic Phosphination and Arsination

    Institute of Scientific and Technical Information of China (English)

    Kwong Fuk Yee; Chan Kin Shing

    2004-01-01

    The catalytic, user-friendly phosphination and arsination of aryl halides and triflates by triphenylphosphine and triphenylarsine using palladium catalysts have provided a facile synthesis of functionalized aryl phosphines and arsines in neutral media. Modification of the cynaoarisne yielded optically active N, As ligands which will be screened in various asymmetric catalysis.

  2. Mitsunobu Reactions Catalytic in Phosphine and a Fully Catalytic System.

    Science.gov (United States)

    Buonomo, Joseph A; Aldrich, Courtney C

    2015-10-26

    The Mitsunobu reaction is renowned for its mild reaction conditions and broad substrate tolerance, but has limited utility in process chemistry and industrial applications due to poor atom economy and the generation of stoichiometric phosphine oxide and hydrazine by-products that complicate purification. A catalytic Mitsunobu reaction using innocuous reagents to recycle these by-products would overcome both of these shortcomings. Herein we report a protocol that is catalytic in phosphine (1-phenylphospholane) employing phenylsilane to recycle the catalyst. Integration of this phosphine catalytic cycle with Taniguchi's azocarboxylate catalytic system provided the first fully catalytic Mitsunobu reaction.

  3. Unusual self-assembled 1D tape of tetramers and water-nitrate clusters trapped in a zinc(II) complex: Synthesis, characterization, luminescence and catalytic properties

    Science.gov (United States)

    Ma, De-Yun; Guo, Hai-Fu; Dong, Ji; Xu, Jun

    2013-12-01

    Unusual tetramers and water-nitrate clusters have been observed in a mononuclear zinc(II) complex of [Zn(4-cpa)(phen)2(H2O)]·(H2O)·(NO3)] (1), (4-Hcpa = 4-chlorophenoxyacetic acid, phen = 1,10-phenanthroline), which was synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction, UV-vis absorption spectra and single-crystal X-ray diffraction. The crystal structure analysis of 1, reveals that the nitrate anions, water molecules and carboxylate oxygen atoms (O3) pack to form a one-dimensional infinite tape parallel to the c-axis. The uncoordinated carboxylate oxygen atoms (O3) of 4-cpa ligands, water molecules and nitrate anions interact via hydrogen bonds and extend 1 into a water-anion-cation tape, which are finally connected into a 3D supramolecular structure via π⋯π stacking interactions. Excitation (λex = 310 nm) and luminescence data observed at room temperature show that 1 emits bright blue fluorescence. Moreover, 1 has a remarkable activity for degradation of methyl orange in a photo-assisted Fenton-like process.

  4. The effect of Rhδ+ dopant in SrTiO3 on the active oxidation state of co-catalytic Pt nanoparticles in overall water splitting

    NARCIS (Netherlands)

    Zoontjes, M.G.C.; Han, K.; Huijben, M.; Wiel, van der W.G.; Mul, G.

    2016-01-01

    We report on the oxidation state of Pt nanoparticles when deposited on SrTiO3 or Rh-doped SrTiO3 under realistic solar water-splitting conditions. The oxidation state was investigated using state-of-the-art analysis of the reaction in a continuously stirred tank reactor (CSTR) connected to a micro g

  5. 催化湿式氧化技术处理苯并三氮唑生产废水的研究%Study on Adopting Catalytic Wet-type Oxidation Technology to Dispose Benzotriazole Production Waste Water

    Institute of Scientific and Technical Information of China (English)

    常建勇; 刘伟

    2011-01-01

    Adopting catalytic wet-type Oxidation to dispose the high concentrated organic waste water produced during the production process of benzotriazole.The experiment demonstrates that the preparation of composite supported catalysts CuO-Co3O4-MnO2/ZrO2-CeO2 have better catalytic activity when disposing the waste water.Through the study of increasing the catalyst investment,reaction temperature,oxygen tension and the PH value of wastewater and other technological conditions,we obtain the optimum technological condition: When catalyst dosing quantity is 10 g/L,reaction temperature is 220℃,oxygen tension is 2.5MPa,the initial PH value of wastewater is 10.5,to react for 120 min under these conditions,CODcr removal rate can reach to 98.2%.%采用催化湿式氧化技术处理在生产苯并三氮唑(BTA)过程中产生的高浓度有机废水。实验证明:制备的复合负载型催化剂CuO-Co3O4-MnO2/ZrO2-CeO2在处理该废水时具有较好的催化活性。通过对催化剂投入增加、反应温度、氧气分压和废水pH值等工艺条件的考察,得出的最佳工艺条件为:催化剂投加量为10g/L,反应温度为220℃,氧气分压为2.5MPa,废水初始pH值为10.5,在此条件下反应120min,CODcr去除率达到98.2%。

  6. Advances in gas flow metering - end of the history, peaceful co-existence or a new beginning; Les avancees dans le mesurage des debits de gaz - fin de l'histoire, coexistence pacifique ou nouveau commencement

    Energy Technology Data Exchange (ETDEWEB)

    Studzinski, W. [NOVA Research and Technology Centre, Calgary (Canada)

    2000-07-01

    Gas flow metering plays an important role in the technical and fiscal operations of pipeline systems. Over the last hundred years, the industry has gone through several technical revolutions. The recent two decades were characterized by the introduction of flow computers in the 80's and acceptance of ultrasonic meters in the 90's. These changes, associated with measurement technology, have had a profound impact on pipeline operation, deregulation of the gas industry and gas trading. Significant advances were made, however, it is certainly not the end for progress in gas flow metering. The future development of optoelectronic and mass flow meters combined with advances in telemetry and tele-calibration may significantly reduce capital and maintenance costs. Classical flow meters will be upgraded to a new level of performance and will co-exist with the newest technologies. The uncertainty of flow measurement will be improved, mainly in terms of stability over longer periods of time. Old and new meters will be able to perform in environments other than dry natural gas. Processing of flow measurement data will evolve with the progress in flow computers and smart transmitters. The advances in gas flow metering will be driven by life cycle cost reduction as well as new business and service requirements. (author)

  7. Microstructural and compositional change of NaOH-activated high calcium fly ash by incorporating Na-aluminate and co-existence of geopolymeric gel and C–S–H(I)

    KAUST Repository

    Oh, Jae Eun

    2012-05-01

    This study explores the reaction products of alkali-activated Class C fly ash-based aluminosilicate samples by means of high-resolution synchrotron X-ray diffraction (HSXRD), scanning electron microscope (SEM), and compressive strength tests to investigate how the readily available aluminum affects the reaction. Class C fly ash-based aluminosilicate raw materials were prepared by incorporating Na-aluminate into the original fly ashes, then alkali-activated by 10 M NaOH solution. Incorporating Na-aluminate reduced the compressive strength of samples, with the reduction magnitude relatively constant regardless of length of curing period. The HSXRD provides evidence of the co-existence of C-S-H with geopolymeric gels and strongly suggests that the C-S-H formed in the current system is C-S-H(I). The back-scattered electron images suggest that the C-S-H(I) phase exists as small grains in a finely intermixed form with geopolymeric gels. Despite providing extra source of aluminum, adding Na-aluminate to the mixes did not decrease the Si/Al ratio of the geopolymeric gel. © 2012 Elsevier Ltd.

  8. Structures of the Ca2+-regulated photoprotein obelin Y138F mutant before and after bioluminescence support the catalytic function of a water molecule in the reaction.

    Science.gov (United States)

    Natashin, Pavel V; Ding, Wei; Eremeeva, Elena V; Markova, Svetlana V; Lee, John; Vysotski, Eugene S; Liu, Zhi-Jie

    2014-03-01

    Ca(2+)-regulated photoproteins, which are responsible for light emission in a variety of marine coelenterates, are a highly valuable tool for measuring Ca(2+) inside living cells. All of the photoproteins are a single-chain polypeptide to which a 2-hydroperoxycoelenterazine molecule is tightly but noncovalently bound. Bioluminescence results from the oxidative decarboxylation of 2-hydroperoxycoelenterazine, generating protein-bound coelenteramide in an excited state. Here, the crystal structures of the Y138F obelin mutant before and after bioluminescence are reported at 1.72 and 1.30 Å resolution, respectively. The comparison of the spatial structures of the conformational states of Y138F obelin with those of wild-type obelin gives clear evidence that the substitution of Tyr by Phe does not affect the overall structure of both Y138F obelin and its product following Ca(2+) discharge compared with the corresponding conformational states of wild-type obelin. Despite the similarity of the overall structures and internal cavities of Y138F and wild-type obelins, there is a substantial difference: in the cavity of Y138F obelin a water molecule corresponding to W2 in wild-type obelin is not found. However, in Ca(2+)-discharged Y138F obelin this water molecule now appears in the same location. This finding, together with the observed much slower kinetics of Y138F obelin, clearly supports the hypothesis that the function of a water molecule in this location is to catalyze the 2-hydroperoxycoelenterazine decarboxylation reaction by protonation of a dioxetanone anion before its decomposition into the excited-state product. Although obelin differs from other hydromedusan Ca(2+)-regulated photoproteins in some of its properties, they are believed to share a common mechanism.

  9. Direct determination of tellurium and its redox speciation at the low nanogram level in natural waters by catalytic cathodic stripping voltammetry.

    Science.gov (United States)

    Biver, Marc; Quentel, François; Filella, Montserrat

    2015-11-01

    Tellurium is one of the elements recently identified as technologically critical and is becoming a new emergent contaminant. No reliable method exists for its determination in environmental samples such as natural waters. This gap is filled by the method described here; it allows the rapid detection of trace concentrations of Te(IV) and Te(VI) in surface waters by differential pulse cathodic stripping voltammetry. It is based on the proton reduction catalysed by the absorption of Te(IV) on the mercury electrode. Under our conditions (0.1 mol L(-1) HCl) a detection limit of about 5 ng L(-1) for a deposition time of 300 s is achieved. Organic matter does not represent a problem at low concentrations; higher concentrations are eliminated by adsorptive purification. Tellurium occurs primarily as Te(IV) and Te(VI) in natural waters. Thus, determining total Te requires the reduction of Te(VI) that it is not electroactive. A number of reduction procedures have been carefully evaluated and a method based on the addition of TiCl3 to the acidified samples has been proven to reduce Te(VI) at the trace level to Te(IV) reliably and quantitatively. Therefore, the procedure described allows the direct determination of total Te and its redox speciation. It is flexible, reliable and cost effective compared to any possible alternative method based on the common preconcentration-ICPMS approach. It is readily implementable as a routine method and can be deployed in the field with relative ease.

  10. Photoelectrochemical water oxidation by screen printed ZnO nanoparticle films: effect of pH on catalytic activity and stability

    Science.gov (United States)

    Fekete, Monika; Riedel, Wiebke; Patti, Antonio F.; Spiccia, Leone

    2014-06-01

    Nanostructured ZnO films are promising photoanode materials in photoelectrochemical water splitting. While such ZnO photoanodes have achieved high activity and good light conversion efficiency in the UV spectral region, their application in water splitting devices has been hampered by the susceptibility of ZnO towards photocorrosion in aqueous electrolytes. We report a systematic investigation aimed at optimising the electrolyte solution to improve the long-term stability of ZnO photoanodes. A stability diagram, based on the band edge positions of ZnO and the pH-dependent photodegradation potentials of ZnO (relative to the decomposition of water), indicates that the optimum pH operating conditions for ZnO photoanodes lie between pH 9-12.5. To verify this prediction experimentally, the activity and long-term stability of uniform screen-printed nano-ZnO films was tested in a wide range of buffered and non-buffered electrolytes (pH 6-13.5). The ZnO films were more active in buffered, than in non-buffered electrolytes, and the highest activities were observed close to the pKa of the phosphate and borate buffers used. Under zero applied potential, these screen-printed films achieved the highest reported photocurrents to date (0.42 mA cm-2 at pH 6 and 0.67 mA cm-2 at pH 10.5) for any pristine or modified ZnO-based water oxidation catalyst. The films were subjected to 12 h of controlled potential electrolysis, in selected electrolytes, under AM 1.5G simulated sunlight. The results are in good agreement with calculations based on thermodynamic data for ZnO. Films tested at pH 6 and 7 (representing typically used operating conditions) degraded rapidly, whereas they exhibited the highest stability when tested in a pH 10.5 borate buffer. In this case, 75% of the initial photoactivity was preserved after 12 hours, indicating that the lifetime of the electrode could be increased by over an order of magnitude compared to standard testing conditions.Nanostructured ZnO films are

  11. Selectivity of catalytic methods of determination.

    Science.gov (United States)

    Otto, M; Mueller, H; Werner, G

    1978-03-01

    By means of catalytic analytical methods, extremely low levels can be determined at low cost and with a high sensitivity that is equal to that of physical methods of trace analysis. The selectivity of the catalytic determinations, is, however, usually rather lower than that of other methods of trace analysis. The selectivity can sometimes be improved by modification of the indicator reaction through variation of the reagents and their concentrations, or by use of masking reagents or activators, or by combination with a separation method. Modification of the indicator reaction can be exemplified by the selective determination of osmium and ruthenium by their catalysis of the nitrate oxidation of 1-naphthylamine. By variation of the nitrate concentration and the use of 1,10-phenanthroline and 8-hydroxyquinoline as complexing agents it is possible to determine these two elements simultaneously. An especially significant increase in the selectivity is made possible by use of a preliminary separation step. If the ion to be determined is separated by solvent extraction and then catalytically determined directly in the extract, a very specific determination is possible; this technique has been called "extractive catalytic determination". This method has been used for determination of molybdenum (0.5 ng/ml) in sea-water, iron (5 ng/ml) in heavy metal salts, and copper (3 ng/ml) in the presence of numerous elements.

  12. Enhanced bromate formation during chlorination of bromide-containing waters in the presence of CuO: Catalytic disproportionation of hypobromous acid

    KAUST Repository

    Liu, Chao

    2012-10-16

    Bromate (BrO3 -) in drinking water is traditionally seen as an ozonation byproduct from the oxidation of bromide (Br-), and its formation during chlorination is usually not significant. This study shows enhanced bromate formation during chlorination of bromide-containing waters in the presence of cupric oxide (CuO). CuO was effective to catalyze hypochlorous acid (HOCl) or hypobromous acid (HOBr) decay (e.g., at least 104 times enhancement for HOBr at pH 8.6 by 0.2 g L-1 CuO). Significant halate concentrations were formed from a CuO-catalyzed hypohalite disproportionation pathway. For example, the chlorate concentration was 2.7 ± 0.2 μM (225.5 ± 16.7 μg L-1) after 90 min for HOCl (Co = 37 μM, 2.6 mg L-1 Cl2) in the presence of 0.2 g L-1 CuO at pH 7.6, and the bromate concentration was 6.6 ± 0.5 μM (844.8 ± 64 μg L -1) after 180 min for HOBr (Co = 35 μM) in the presence of 0.2 g L-1 CuO at pH 8.6. The maximum halate formation was at pHs 7.6 and 8.6 for HOCl or HOBr, respectively, which are close to their corresponding pKa values. In a HOCl-Br--CuO system, BrO3 - formation increases with increasing CuO doses and initial HOCl and Br- concentrations. A molar conversion (Br - to BrO3 -) of up to (90 ± 1)% could be achieved in the HOCl-Br--CuO system because of recycling of Br - to HOBr by HOCl, whereas the maximum BrO3 - yield in HOBr-CuO is only 26%. Bromate formation is initiated by the formation of a complex between CuO and HOBr/OBr-, which then reacts with HOBr to generate bromite. Bromite is further oxidized to BrO3 - by a second CuO-catalyzed process. These novel findings may have implications for bromate formation during chlorination of bromide-containing drinking waters in copper pipes. © 2012 American Chemical Society.

  13. Hydrogen production from co-gasification of coal and biomass in supercritical water by continuous flow thermal-catalytic reaction system

    Institute of Scientific and Technical Information of China (English)

    YAN Qiuhui; GUO Liejin; LIANG Xing; ZHANG Ximin

    2007-01-01

    Hydrogen is a clean energy carrier.Converting abundant coal sources and green biomass energy into hydrogen effectively and without any pollution promotes environmental protection.The co-gasification performance of coal and a model compound of biomass,carboxymethylcellulose (CMC)in supercritical water (SCW),were investigated experimentally.The influences of temperature,pressure and concentration on hydrogen production from co-gasification of coal and CMC in SCW under the given conditions (20-25 MPa,650℃,15-30 s) are discussed in detail.The experimental results show that H2,CO2 and CH4 are the main gas products,and the molar fraction of hydrogen reaches in excess of 60%.The higher pressure and higher CMC content facilitate hydrogen production;production is decreased remarkably given a longer residence time.

  14. CATALYTIC REDUCTION OF NITRATE IN WATER OVER Pd-Cu/AC CATALYST%钯—铜负载活性炭催化还原去除水中硝酸盐研究

    Institute of Scientific and Technical Information of China (English)

    汪昆平; 刘苗苗; 徐乾前; 郭劲松; 汪春燕; 赵越

    2011-01-01

    Based on the Pd-Cu/AC catalyst prepared by impregnation, the removal of nitrate from water was researched using semi-continuous experiments. The results demonstrated that the catalyst had the best activity and selectivity when the Pd/Cu ratio,the Pd loading,the Cu loading were 1:1, 1.2%,0.72%,respectively. The catalytic reaction had a rapid proceed and better selectivity at the H2 flow rate of 100 mL min'. The appropriate range of pH was 4.5~5.5, while too high or too low pH value resulted in the low catalytic activity and selectivity. The conversion of nitrate was over 96%, and the production rate of ammonium was 22% in 2 hours for the 100 mg- L' nitrate solution.%通过以活性炭载体浸渍负载钯铜双金属制备的催化剂,利用半连续试验,研究了活性炭载体双金属催化剂对水中硝酸盐的催化还原去除的特点和规律.结果表明,在负载钯/铜原子比为1∶1、金属负载量Pd质量分数为1.2%、Cu质量分数为0.72%时,催化剂具有最佳的活性与选择性;最佳H2流量为100 mL· min-1,此时催化反应进行迅速,选择性较好;溶液pH过高或者过低对催化剂活性和选择性都有不利影响,适宜的溶液pH控制范围为4.5~5.5;对于初始质量浓度为100 mg·L-1的硝酸盐溶液,反应时间为2h时,硝酸盐去除率可达96%以上,氨氮生成率为22%.

  15. Catalytic ozonation of trace p-chloronitrobenzene in water by nano-CuO catalyst%纳米CuO催化臭氧化降解水中痕量对硝基氯苯的研究

    Institute of Scientific and Technical Information of China (English)

    翟旭; 陈忠林; 杨磊; 刘婷; 刘玥

    2009-01-01

    Nano-CuO prepared in the lab was used as catalyst to enhance the ozonation for the removal of trace p-chloronitrobenzene (pCNB) in water. The experiments were carried out to investigate the effects of different process conditions, the amount of catalyst, pH value, ozone gas concentrations and tert-butanol on the degradation efficiency of pCNB. Results showed that under the present experimental conditions, the presence of nano-CuO could improve the ozonation for removal of pCNB, namely the removal efficiency of pCNB was increased by 28% compared to the case of ozonation alone within the 12 min treatment. With the increase of the amount of catalyst, pH value (3 ?11) and ozone gas concentrations, the removal efficiency of pCNB increased, respectively. It was found that the removal efficiency of pCNB decreased as the concentration of tert-butanol increased in the process of catalytic ozonation , indicating that the degradation of pCNB is mainly contributed to the oxidation of hydroxyl radicals in the nano-CuO catalytic ozonation process.%采用实验室制备的纳米CuO为催化剂,对水中痕量的对硝基氯苯(pCNB)进行催化臭氧氧化去除效能研究.考察了不同工艺条件、催化剂用量、溶液pH值、臭氧进气浓度以及叔丁醇等因素对有机物去除效能的影响.结果表明:在实验条件下,纳米CuO对臭氧氧化去除水中的pCNB具有明显的催化效果,12 min内,催化臭氧氧化对pCNB的去除率比单独臭氧氧化提高了28%.随着催化剂用量、pH值(3~11)和臭氧进气浓度的增加,pCNB去除率均增大.自由基抑制剂叔丁醇的加入使pCNB去除率明显降低,证明在纳米CuO催化臭氧化过程中pCNB的降解主要是由于羟基自由基的氧化作用.

  16. Si-FeOOH催化臭氧氧化降解活性艳红MX-5B的效能研究%Catalytic ozonation of active red MX-5B in water with Si-FeOOH

    Institute of Scientific and Technical Information of China (English)

    周康; 霍明昕; 汪小雄; 姜成春

    2013-01-01

    通过共沉淀的方法在羟基氧化铁(FeOOH)合成过程中掺入硅(Si)来制备硅羟基氧化铁(Si-FeOOH)催化剂,比较其与FeOOH在物理强度等方面的差异,同时研究Si-FeOOH催化臭氧氧化降解活性艳红的效能、推断反应机理、考察各种因素对脱色率的影响.结果表明:相对于FeOOH,Si-FeOOH的物理强度有所提高,在水溶液中不易破碎;Si-FeOOH催化臭氧氧化降解活性艳红效果显著,比单独臭氧氧化的脱色率有较大提高;催化过程遵循自由基反应机理;脱色率随着臭氧浓度的增加而升高,在应用Si-FeOOH催化臭氧对染料脱色时存在最佳催化剂投量;Si-FeOOH在中性条件下其催化活性显著,催化剂性能稳定,可重复利用.%In this study, Si was added into FeOOH to prepare Si-FeOOH, and the physical intensity and other properties of Si-FeOOH and FeOOH were compared. The influencing factors of Si-FeOOH-catalyzed ozone on red MX-5B degradation were studied, and the reaction mechanism and the efficiency of decolorization ratio were investigated. The result indicated that, compared with FeOOH, Si-FeOOH had higher physical intensity and was not likely to be crushed in water solution. The iron dissolution was effectively prevented because of the addition of Si, and the effect of Si-FeOOH-catalyzed ozone on red MX-5B degradation was obvious. The decolorization ratio of Si-FeOOH was improved, and the catalytic process followed free radical reaction mechanism. The decolorization ratios increased in response to the increased ozone concentration, whereas the dosage of the catalyst existed an optimum value. Si-FeOOH had a distinct catalytic activity under the neutral condition. The capability of the catalyst was stable, and the catalyst can he recycled and reused.

  17. Facile electrochemical co-deposition of a graphene-cobalt nanocomposite for highly efficient water oxidation in alkaline media: direct detection of underlying electron transfer reactions under catalytic turnover conditions.

    Science.gov (United States)

    Guo, Si-Xuan; Liu, Yuping; Bond, Alan M; Zhang, Jie; Esakki Karthik, P; Maheshwaran, I; Senthil Kumar, S; Phani, K L N

    2014-09-21

    A facile electrochemical co-deposition method has been developed for the fabrication of graphene-cobalt nanocomposite modified electrodes that achieve exceptionally efficient water oxidation in highly alkaline media. In the method reported, a graphene-cobalt nanocomposite film was deposited electrochemically from a medium containing 1 mg ml(-1) graphene oxide, 0.8 mM cobalt nitrate and 0.05 M phytic acid (pH 7). The formation of the nanocomposite film was confirmed using electrochemical, Raman spectroscopic and scanning electron microscopic techniques. The nanocomposite film exhibits excellent activity and stability towards water oxidation to generate oxygen in 1 M NaOH aqueous electrolyte media. A turn over frequency of 34 s(-1) at an overpotential of 0.59 V and a faradaic efficiency of 97.7% were deduced from analysis of data obtained by rotating ring disk electrode voltammetry. Controlled potential electrolysis data suggests that the graphene supported catalyst exhibits excellent stability under these harsh conditions. Phytate anion acts as stabilizer for the electrochemical formation of cobalt nanoparticles. Fourier transformed ac voltammetry allowed the redox chemistry associated with catalysis to be detected directly under catalytic turnover conditions. Estimates of formal reversible potentials obtained from this method and derived from the overall reactions 3Co(OH)2 + 2OH(-) ⇌ Co3O4 + 4H2O + 2e(-), Co3O4 + OH(-) ⇌ 3CoOOH + e(-) and CoOOH + OH(-) ⇌ CoO2 + H2O + e(-) are 0.10, 0.44 and 0.59 V vs. Ag/AgCl, respectively.

  18. Catalytic Polymer Multilayer Shell Motors for Separation of Organics.

    Science.gov (United States)

    Lin, Zhihua; Wu, Zhiguang; Lin, Xiankun; He, Qiang

    2016-01-26

    A catalytic polymer multilayer shell motor has been developed, which effects fast motion-based separation of charged organics in water. The shell motors are fabricated by sputtering platinum onto the exposed surface of silica templates embedded in Parafilm, followed by layer-by-layer assembly of polyelectrolyte multilayers to the templates. The catalytic shell motors display high bubble propulsion with speeds of up to 260 μm s(-1) (13 body lengths per second). Moreover, the polyelectrolyte multilayers assembled at high pH (pH>9.0) adsorb approximately 89% of dye molecules from water, owing to the electrostatic interaction between the positively charged polymers and the anionic dye molecules, and subsequently release them at neutral pH in a microfluidic device. The efficient propulsion coupled with the effective adsorption behavior of the catalytic shell motors in a microfluidic device results in accelerated separation of organics in water and thus holds considerable promise for water analysis.

  19. Preparation and Water-Gas Shift Catalytic Activities of the Perovskite Type Complex Oxide La1-x CexFeO3

    Institute of Scientific and Technical Information of China (English)

    马红钦; 谭欣; 朱慧铭; 张继炎; 张鎏

    2003-01-01

    The perovskite type rare-earth iron complex (REIC) oxide La1-xCexFeO3 is designed and prepared as water-gas shift catalyst. Activity evaluation and heat-resisting test show that the perovskite type compounds La1-xCexFeO3 (· K) has a good thermal stability if x is less than or equal to 0. 5. But when x is greater than 0. 5, La1-x Cex FeO3 ( · K) will turn out to be ceria and magnetite partially or completely at high temperature in the shift reaction atmosphere. In the case of x = 0. 5, the conversion of carbon monoxide is about 68% at 530℃. Potassium can greatly improve the low temperature activity, but slightly lower the high temperature activity,and has little impact on the thermal stability. La0.5 Ce0.5 FeO3 ( · K) is a promising chromium-free high-temperature shift catalyst.

  20. Preparation and High-Temperature Water-Gas Shift Catalytic Features of La1-xCexFeO3 Perovskite

    Institute of Scientific and Technical Information of China (English)

    马红钦; 朱慧铭; 谭欣; 张继炎; 张鎏

    2004-01-01

    Based on water-gas shift reaction mechanism and perovskite compounds characteristics, La1-xCexFeO3 (.K) perovskite were designed and prepared as shift catalysts. DTA and XRD results reveal that La1-xCexFeO3 can be formed at 730~760 ℃ by mechanic-mix thermal decomposition method. Activity and heat-resisting tests show that La1-xCexFeO3 (.K) possess high thermal stability if x is less than or equals to 0.5. But when x is greater than 0.5, La1-xCexFeO3 (.K) will be converted into ceria and magnetite partially or completely under shift reaction conditions. In the case of x=0.5, the conversion of CO is about 68% at 530 ℃. Potassium can greatly improve the low temperature activity, but slightly reduces the high temperature activity, and has little impact on the thermal stability. La0.5Ce0.5FeO3 (.K) is a promising chromium-free high temperature shift catalyst.

  1. Unusual Physical and Chemical Properties of Ni in Ce1-xNixO2-y Oxides: Structural Characterization and Catalytic Activity for the Water Gas Shift Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Barrio, L.; Kubacka, A; Zhou, G; Estrella, M; Martinez-Arias, A; Hanson, J; Fernandez-Garcia, M; Rodriguez, J

    2010-01-01

    The structural and electronic properties of Ce{sub 1-x}Ni{sub x}O{sub 2-y} nanosystems prepared by a reverse microemulsion method were characterized with synchrotron-based X-ray diffraction, X-ray absorption spectroscopy, Raman spectroscopy, and density functional calculations. The Ce{sub 1-x}Ni{sub x}O{sub 2-y} systems adopt a lattice with a fluorite-type structure with an acute local order where Ni displays a strongly distorted (oxygen) nearest-neighbor coordination and the presence of Ni atoms as first cation distances, pointing to the existence of Ni-O-Ni entities embedded into the ceria lattice. A Ni {leftrightarrow} Ce exchange within the CeO{sub 2} leads to a charge redistribution and the appearance of O vacancies. The Ni-O bonds in Ce{sub 1-x}Ni{sub x}O{sub 2-y} are more difficult to reduce than the bonds in pure NiO. The specific structural configuration of Ni inside the mixed-metal oxide leads to a unique catalyst with a high activity for the water gas shift (CO + H{sub 2}O {yields} H{sub 2} + CO{sub 2}) reaction and a simultaneous reduction of the methanation activity of nickel. Characterization results indicate that small particles of metallic Ni at the interface position of a ceria network may be the key for high WGS activity and that the formate-carbonate route is operative for the production of hydrogen.

  2. Unusual Physical and Chemical Properties of Ni in Ce1-xNixO2-y Oxides: Structural Characterization and Catalytic Activity for the Water Gas Shift Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, J.A.; Barrio, L.; Kubacka, A.; Zhou, G.; Estrella, M.; Mart& #305; nez-Arias, A.; Hanson, J.C.; Fernandez-Garc& #305; a, M.

    2010-07-29

    The structural and electronic properties of Ce{sub 1-x}Ni{sub x}O{sub 2-y} nanosystems prepared by a reverse microemulsion method were characterized with synchrotron-based X-ray diffraction, X-ray absorption spectroscopy, Raman spectroscopy, and density functional calculations. The Ce{sub 1-x}Ni{sub x}O{sub 2-y} systems adopt a lattice with a fluorite-type structure with an acute local order where Ni displays a strongly distorted (oxygen) nearest-neighbor coordination and the presence of Ni atoms as first cation distances, pointing to the existence of Ni-O-Ni entities embedded into the ceria lattice. A Ni {leftrightarrow} Ce exchange within the CeO{sub 2} leads to a charge redistribution and the appearance of O vacancies. The Ni?O bonds in Ce{sub 1-x}Ni{sub x}O{sub 2-y} are more difficult to reduce than the bonds in pure NiO. The specific structural configuration of Ni inside the mixed-metal oxide leads to a unique catalyst with a high activity for the water gas shift (CO + H{sub 2}O {yields} H{sub 2} + CO{sub 2}) reaction and a simultaneous reduction of the methanation activity of nickel. Characterization results indicate that small particles of metallic Ni at the interface position of a ceria network may be the key for high WGS activity and that the formate?carbonate route is operative for the production of hydrogen.

  3. Numerical Study of Passive Catalytic Recombiner for Hydrogen Mitigation

    Directory of Open Access Journals (Sweden)

    Pavan K Sharma

    2010-10-01

    Full Text Available A significant amount of hydrogen is expected to be released within the containment of a water cooled power reactor after a severe accident. To reduce the risk of deflagration/detonation various means for hydrogen control have been adopted all over the world. Passive catalytic recombiner with vertical flat catalytic plate is one of such hydrogen mitigating device. Passive catalytic recombiners are designed for the removal of hydrogen generated in order to limit the impact of possible hydrogen combustion. Inside a passive catalytic recombiner, numerous thin steel sheets coated with catalyst material are vertically arranged at the bottom opening of a sheet metal housing forming parallel flow channels for the surrounding gas atmosphere. Already below conventional flammability limits, hydrogen and oxygen react exothermally on the catalytic surfaces forming harmless steam. Detailed numerical simulations and experiments are required for an in-depth knowledge of such plate type catalytic recombiners. Specific finite volume based in-house CFD code has been developed to model and analyse the working of these recombiner. The code has been used to simulate the recombiner device used in the Gx-test series of Battelle-Model Containment (B-MC experiments. The present paper briefly describes the working principle of such passive catalytic recombiner and salient feature of the CFD model developed at Bhabha Atomic Research Centre (BARC. Finally results of the calculations and comparison with existing data are discussed.

  4. PREPARATION AND CATALYTIC ACTIVITY OF BIOACTIVE FIBERS

    Institute of Scientific and Technical Information of China (English)

    Yu-yuan Yao; Wen-xing Chen; Bao-yan Zhao; Shen-shui Lü

    2006-01-01

    Two kinds of water-soluble metallophthalocyanines, binuclear cobalt phthalocyanine (Co2Pc2) and binuclear ferric phthalocyanine (Fe2Pc2), were synthesized through phenylanhydride-urea route and characterized by elemental analysis and FT-IR spectra. Binuclear metallophthalocyanine derivatives (Mt2Pc2) were immobilized on silk fibers and modified viscose fibers to construct bioactive fibers of mimic enzyme. Mt2Pc2 was used as the active center ofbioactive fibers, viscose and silk fibers as the microenvironments. The catalytic oxidation ability of bioactive fibers on the malodors of methanthiol and hydrogen sulfide was investigated at room temperature. The experimental results indicated that the catalytic activity of such bioactive fibers was closely correlative to the types ofbioactive fibers and substrates.

  5. HYDROGEN TRANSFER IN CATALYTIC CRACKING

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Hydrogen transfer is an important secondary reaction of catalytic cracking reactions, which affects product yield distribution and product quality. It is an exothermic reaction with low activation energy around 43.3 kJ/mol. Catalyst properties and operation parameters in catalytic cracking greatly influence the hydrogen transfer reaction. Satisfactory results are expected through careful selection of proper catalysts and operation conditions.

  6. A new monetary phenomenon: An analysis of the co-existence of the external appreciation and the domestic inflation of RMB%试析人民币对外升值与对内贬值并存

    Institute of Scientific and Technical Information of China (English)

    贝多广; 朱晓莉

    2008-01-01

    Since 2002,RMB has shown a phenomenon which is the co-existence of the external appreciation and the domestic inflation.This new monetary phenomenon has been strengthened in the context that US dollar depreciates internationally and that domestic economy is overwhelmed with excessive liquidities.The new monetary phenomenon is the reflection of the real economy that continuing trade surplus,triggered robustly by the export-driven economy,which brings a huge amount of foreign exchange reserve and accelerates sequentially the expansion of domestic money supply.Furthermore,a refrained appreciation of RMB tends to deteriorate the domestic inflation,which is not simply a traditional concept of CPI but a broad inflation parameter including a variety of asset prices.It is sure that the new phenomenon is becoming a new challenge to the macroeconomic equilibrium as well as the decision maker of monetary policy.%2002年以来,人民币出现了对外升值和对内贬值并存的现象.在国际美元贬值和国内流动性过剩的背景下,这一货币现象得到了强化.这一货币现象是实际经济运行的反映:中国的出口导向型经济强势增长,国际收支持续顺差带来巨额外汇储备,进而推动国内货币供应量的扩张.当汇率和资本流动都受到管制时,压抑的对外升值趋势会成为对内贬值的直接原因.而对内贬值的概念已不是传统意义上的CPI上涨,而是包括资产价格膨胀在内的广义通货膨胀.这对于宏观经济平衡和货币政策制定者来说,都是一场新的挑战.

  7. Catalytic quantum error correction

    CERN Document Server

    Brun, T; Hsieh, M H; Brun, Todd; Devetak, Igor; Hsieh, Min-Hsiu

    2006-01-01

    We develop the theory of entanglement-assisted quantum error correcting (EAQEC) codes, a generalization of the stabilizer formalism to the setting in which the sender and receiver have access to pre-shared entanglement. Conventional stabilizer codes are equivalent to dual-containing symplectic codes. In contrast, EAQEC codes do not require the dual-containing condition, which greatly simplifies their construction. We show how any quaternary classical code can be made into a EAQEC code. In particular, efficient modern codes, like LDPC codes, which attain the Shannon capacity, can be made into EAQEC codes attaining the hashing bound. In a quantum computation setting, EAQEC codes give rise to catalytic quantum codes which maintain a region of inherited noiseless qubits. We also give an alternative construction of EAQEC codes by making classical entanglement assisted codes coherent.

  8. Catalytic Combustion of Gasified Waste

    Energy Technology Data Exchange (ETDEWEB)

    Kusar, Henrik

    2003-09-01

    This thesis concerns catalytic combustion for gas turbine application using a low heating-value (LHV) gas, derived from gasified waste. The main research in catalytic combustion focuses on methane as fuel, but an increasing interest is directed towards catalytic combustion of LHV fuels. This thesis shows that it is possible to catalytically combust a LHV gas and to oxidize fuel-bound nitrogen (NH{sub 3}) directly into N{sub 2} without forming NO{sub x} The first part of the thesis gives a background to the system. It defines waste, shortly describes gasification and more thoroughly catalytic combustion. The second part of the present thesis, paper I, concerns the development and testing of potential catalysts for catalytic combustion of LHV gases. The objective of this work was to investigate the possibility to use a stable metal oxide instead of noble metals as ignition catalyst and at the same time reduce the formation of NO{sub x} In paper II pilot-scale tests were carried out to prove the potential of catalytic combustion using real gasified waste and to compare with the results obtained in laboratory scale using a synthetic gas simulating gasified waste. In paper III, selective catalytic oxidation for decreasing the NO{sub x} formation from fuel-bound nitrogen was examined using two different approaches: fuel-lean and fuel-rich conditions. Finally, the last part of the thesis deals with deactivation of catalysts. The various deactivation processes which may affect high-temperature catalytic combustion are reviewed in paper IV. In paper V the poisoning effect of low amounts of sulfur was studied; various metal oxides as well as supported palladium and platinum catalysts were used as catalysts for combustion of a synthetic gas. In conclusion, with the results obtained in this thesis it would be possible to compose a working catalytic system for gas turbine application using a LHV gas.

  9. Catalytic performance and thermostability of chloroperoxidase in reverse micelle: achievement of a catalytically favorable enzyme conformation.

    Science.gov (United States)

    Wang, Yali; Wu, Jinyue; Ru, Xuejiao; Jiang, Yucheng; Hu, Mancheng; Li, Shuni; Zhai, Quanguo

    2011-06-01

    The catalytic performance of chloroperoxidase (CPO) in peroxidation of 2, 2'-azinobis-(-3 ethylbenzothiazoline-6-sulfononic acid) diammonium salt (ABTS) and oxidation of indole in a reverse micelle composed of surfactant-water-isooctane-pentanol was investigated and optimized in this work. Some positive results were obtained as follows: the peroxidation activity of CPO was enhanced 248% and 263%, while oxidation activity was enhanced 215% and 222% in cetyltrimethylammonium bromide (CTABr) reverse micelle medium and dodecyltrimethylammonium bromide (DTABr) medium, respectively. Thermostability was also greatly improved in reverse micelle: at 40 °C, CPO essentially lost all its activity after 5 h incubation, while 58-76% catalytic activity was retained for both reactions in the two reverse micelle media. At 50 °C, about 44-75% catalytic activity remained for both reactions in reverse micelle after 2 h compared with no observed activity in pure buffer under the same conditions. The enhancement of CPO activity was dependent mainly on the surfactant concentration and structure, organic solvent ratio (V(pentanol)/V(isooctane)), and water content in the reverse micelle. The obtained kinetic parameters showed that the catalytic turnover frequency (k(cat)) was increased in reverse micelle. Moreover, the lower K(m) and higher k(cat)/K(m) demonstrated that both the affinity and specificity of CPO to substrates were improved in reverse micelle media. Fluorescence, circular dichroism (CD) and UV-vis spectra assays indicated that a catalytically favorable conformation of enzyme was achieved in reverse micelle, including the strengthening of the protein α-helix structure, and greater exposure of the heme prosthetic group for easy access of the substrate in bulk solution. These results are promising in view of the industrial applications of this versatile biological catalyst.

  10. Water

    Science.gov (United States)

    ... www.girlshealth.gov/ Home Nutrition Nutrition basics Water Water Did you know that water makes up more ... to drink more water Other drinks How much water do you need? top Water is very important, ...

  11. Unsteady catalytic processes and sorption-catalytic technologies

    Energy Technology Data Exchange (ETDEWEB)

    Zagoruiko, A N [G.K. Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2007-07-31

    Catalytic processes that occur under conditions of the targeted unsteady state of the catalyst are considered. The highest efficiency of catalytic processes was found to be ensured by a controlled combination of thermal non-stationarity and unsteady composition of the catalyst surface. The processes based on this principle are analysed, in particular, catalytic selective reduction of nitrogen oxides, deep oxidation of volatile organic impurities, production of sulfur by the Claus process and by hydrogen sulfide decomposition, oxidation of sulfur dioxide, methane steam reforming and anaerobic combustion, selective oxidation of hydrocarbons, etc.

  12. Catalytic pyrolysis of olive mill wastewater sludge

    Science.gov (United States)

    Abdellaoui, Hamza

    From 2008 to 2013, an average of 2,821.4 kilotons/year of olive oil were produced around the world. The waste product of the olive mill industry consists of solid residue (pomace) and wastewater (OMW). Annually, around 30 million m3 of OMW are produced in the Mediterranean area, 700,000 m3 year?1 in Tunisia alone. OMW is an aqueous effluent characterized by an offensive smell and high organic matter content, including high molecular weight phenolic compounds and long-chain fatty acids. These compounds are highly toxic to micro-organisms and plants, which makes the OMW a serious threat to the environment if not managed properly. The OMW is disposed of in open air evaporation ponds. After evaporation of most of the water, OMWS is left in the bottom of the ponds. In this thesis, the effort has been made to evaluate the catalytic pyrolysis process as a technology to valorize the OMWS. The first section of this research showed that 41.12 wt. % of the OMWS is mostly lipids, which are a good source of energy. The second section proved that catalytic pyrolysis of the OMWS over red mud and HZSM-5 can produce green diesel, and 450 °C is the optimal reaction temperature to maximize the organic yields. The last section revealed that the HSF was behind the good fuel-like properties of the OMWS catalytic oils, whereas the SR hindered the bio-oil yields and quality.

  13. Highly sensitive catalytic spectrophotometric determination of ruthenium

    Science.gov (United States)

    Naik, Radhey M.; Srivastava, Abhishek; Prasad, Surendra

    2008-01-01

    A new and highly sensitive catalytic kinetic method (CKM) for the determination of ruthenium(III) has been established based on its catalytic effect on the oxidation of L-phenylalanine ( L-Pheala) by KMnO 4 in highly alkaline medium. The reaction has been followed spectrophotometrically by measuring the decrease in the absorbance at 526 nm. The proposed CKM is based on the fixed time procedure under optimum reaction conditions. It relies on the linear relationship where the change in the absorbance (Δ At) versus added Ru(III) amounts in the range of 0.101-2.526 ng ml -1 is plotted. Under the optimum conditions, the sensitivity of the proposed method, i.e. the limit of detection corresponding to 5 min is 0.08 ng ml -1, and decreases with increased time of analysis. The method is featured with good accuracy and reproducibility for ruthenium(III) determination. The ruthenium(III) has also been determined in presence of several interfering and non-interfering cations, anions and polyaminocarboxylates. No foreign ions interfered in the determination ruthenium(III) up to 20-fold higher concentration of foreign ions. In addition to standard solutions analysis, this method was successfully applied for the quantitative determination of ruthenium(III) in drinking water samples. The method is highly sensitive, selective and very stable. A review of recently published catalytic spectrophotometric methods for the determination of ruthenium(III) has also been presented for comparison.

  14. Catalytic production of biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Theilgaard Madsen, A.

    2011-07-01

    The focus of this thesis is the catalytic production of diesel from biomass, especially emphasising catalytic conversion of waste vegetable oils and fats. In chapter 1 an introduction to biofuels and a review on different catalytic methods for diesel production from biomass is given. Two of these methods have been used industrially for a number of years already, namely the transesterification (and esterification) of oils and fats with methanol to form fatty acid methyl esters (FAME), and the hydrodeoxygenation (HDO) of fats and oils to form straight-chain alkanes. Other possible routes to diesel include upgrading and deoxygenation of pyrolysis oils or aqueous sludge wastes, condensations and reductions of sugars in aqueous phase (aqueous-phase reforming, APR) for monofunctional hydrocarbons, and gasification of any type of biomass followed by Fischer-Tropsch-synthesis for alkane biofuels. These methods have not yet been industrialised, but may be more promising due to the larger abundance of their potential feedstocks, especially waste feedstocks. Chapter 2 deals with formation of FAME from waste fats and oils. A range of acidic catalysts were tested in a model fat mixture of methanol, lauric acid and trioctanoin. Sulphonic acid-functionalised ionic liquids showed extremely fast convertion of lauric acid to methyl laurate, and trioctanoate was converted to methyl octanoate within 24 h. A catalyst based on a sulphonated carbon-matrix made by pyrolysing (or carbonising) carbohydrates, so-called sulphonated pyrolysed sucrose (SPS), was optimised further. No systematic dependency on pyrolysis and sulphonation conditions could be obtained, however, with respect to esterification activity, but high activity was obtained in the model fat mixture. SPS impregnated on opel-cell Al{sub 2}O{sub 3} and microporous SiO{sub 2} (ISPS) was much less active in the esterification than the original SPS powder due to low loading and thereby low number of strongly acidic sites on the

  15. Catalytic performance of Fe3O4-CoO/Al2O3 catalyst in ozonation of 2-(2,4-dichlorophenoxy) propionic acid,nitrobenzene and oxalic acid in water

    Institute of Scientific and Technical Information of China (English)

    Shaoping Tong; Rui Shi; Hua Zhang; Chunan Ma

    2010-01-01

    the precursors,and its catalytic performance was investigated in ozonation of 2-(2,4-dichlorophenoxy) propionic acid (2,4-DP),nitrobenzene and oxalic acid.The experimental results indicated that Fe3O4-CoO/Al2O3 catalyst enabled an interesting improvement of ozonation efficiency during the degradation of each organic pollutant,and the Fe3O4-CoO/Al2O3 catalytic ozonation system followed a radical-type mechanism.The kinetics of ozonation alone and Fe3O4-CoO/Al2O3 catalytic ozonation of three organic pollutants in aqueous solution were discussed under the mere consideration of direct ozone reaction and OH radical reaction to well investigate its performance.In the catalytic ozonation of 2,4-DP,the apparent reaction rate constants (k) were determined to be 1.456×10-2 min-1 for ozonation alone and 4.740×10-2 min-1 for O3/Fe3O4-CoO/Al2O3.And O3/Fe3O4-CoO/Al2O3 had a larger Rct (6.614×10-9) calculated by the relative method than O3 did (1.800×10-9),showing O3/Fe3O4-CoO/Al2O3 generated more hydroxyl radical.Similar results were also obtained in the catalytic ozonation of nitrobenzene and oxalic acid.The above results demonstrated that the catalytic performance of Fe3O4-CoO/Al2O3 in ozonation of studied organic substance was universal to a certain degree.

  16. Changes of Serotonin (5-HT), 5-HT2A Receptor, and 5-HT Transporter in the Sprague-Dawley Rats of Depression,Myocardial Infarction and Myocardial Infarction Co-exist with Depression

    Institute of Scientific and Technical Information of China (English)

    Mei-Yan Liu; Yah-Ping Ren; Wan-Lin Wei; Guo-Xiang Tian; Guo Li

    2015-01-01

    Background:To evaluate whether serotonin (5-HT),5-HT2A receptor (5-HT2AR),and 5-HT transporter (serotonin transporter [SERT]) are associated with different disease states of depression,myocardial infarction (MI) and MI co-exist with depression in Sprague-Dawley rats.Methods:After established the animal model of four groups include control,depression,MI and MI with depression,we measured 5-HT,5-HT2AR and SERT from serum and platelet lysate.Results:The serum concentration of 5-HT in depression rats decreased significantly compared with the control group (303.25 ± 9.99 vs.352.98 ± 13.73;P =0.000),while that in MI group increased (381.78 ± 14.17 vs.352.98 ± 13.73;P =0.000).However,the depression + MI group had no change compared with control group (360.62 ± 11.40 vs.352.98 ± 13.73;P =0.036).The changes of the platelet concentration of 5-HT in the depression,MI,and depression + MI group were different from that of serum.The levels of 5-HT in above three groups were lower than that in the control group (380.40 ± 17.90,387.75 ± 22.28,246.40 ± 18.99 vs.500.29 ± 20.91;P =0.000).The platelet lysate concentration of 5-HT2AR increased in depression group,MI group,and depression + MI group compared with the control group (370.75 ± 14.75,393.47 ± 15.73,446.66 ± 18.86 vs.273.66 ± 16.90;P =0.000).The serum and platelet concentration of SERT in the depression group,MI group and depression + MI group were all increased compared with the control group (527.51 ± 28.32,602.02 ± 23.32,734.76 ± 29.59 vs.490.56 ± 16.90;P =0.047,P =0.000,P =0.000 in each and 906.38 ± 51.84,897.33 ± 60.34,1030.17 ± 58.73 vs.708.62 ± 51.15;P =0.000 in each).Conclusions:The concentration of 5-HT2AR in platelet lysate and SERT in serum and platelet may be involved in the pathway of MI with depression.Further studies should examine whether elevated 5-HT2AR and SERT may contribute to the biomarker in MI patients with depression.

  17. Catalytic activities of zeolite compounds for decomposing aqueous ozone.

    Science.gov (United States)

    Kusuda, Ai; Kitayama, Mikito; Ohta, Yoshio

    2013-12-01

    The advanced oxidation process (AOP), chemical oxidation using aqueous ozone in the presence of appropriate catalysts to generate highly reactive oxygen species, offers an attractive option for removing poorly biodegradable pollutants. Using the commercial zeolite powders with various Si/Al ratios and crystal structures, their catalytic activities for decomposing aqueous ozone were evaluated by continuously flowing ozone to water containing the zeolite powders. The hydrophilic zeolites (low Si/Al ratio) with alkali cations in the crystal structures were found to possess high catalytic activity for decomposing aqueous ozone. The hydrophobic zeolite compounds (high Si/Al ratio) were found to absorb ozone very well, but to have no catalytic activity for decomposing aqueous ozone. Their catalytic activities were also evaluated by using the fixed bed column method. When alkali cations were removed by acid rinsing or substituted by alkali-earth cations, the catalytic activities was significantly deteriorated. These results suggest that the metal cations on the crystal surface of the hydrophilic zeolite would play a key role for catalytic activity for decomposing aqueous ozone.

  18. Catalytic Membrane Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, T.J.; Brinker, C.J.; Gardner, T.J.; Hughes, R.C.; Sault, A.G.

    1998-12-01

    The proposed "catalytic membrane sensor" (CMS) was developed to generate a device which would selectively identify a specific reagent in a complex mixture of gases. This was to be accomplished by modifying an existing Hz sensor with a series of thin films. Through selectively sieving the desired component from a complex mixture and identifying it by decomposing it into Hz (and other by-products), a Hz sensor could then be used to detect the presence of the select component. The proposed "sandwich-type" modifications involved the deposition of a catalyst layered between two size selective sol-gel layers on a Pd/Ni resistive Hz sensor. The role of the catalyst was to convert organic materials to Hz and organic by-products. The role of the membraneo was to impart both chemical specificity by molecukir sieving of the analyte and converted product streams, as well as controlling access to the underlying Pd/Ni sensor. Ultimately, an array of these CMS elements encompassing different catalysts and membranes were to be developed which would enable improved selectivity and specificity from a compiex mixture of organic gases via pattern recognition methodologies. We have successfully generated a CMS device by a series of spin-coat deposited methods; however, it was determined that the high temperature required to activate the catalyst, destroys the sensor.

  19. Catalytic cracking of lignites

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, M.; Nowak, S.; Naegler, T.; Zimmermann, J. [Hochschule Merseburg (Germany); Welscher, J.; Schwieger, W. [Erlangen-Nuernberg Univ. (Germany); Hahn, T. [Halle-Wittenberg Univ., Halle (Germany)

    2013-11-01

    A most important factor for the chemical industry is the availability of cheap raw materials. As the oil price of crude oil is rising alternative feedstocks like coal are coming into focus. This work, the catalytic cracking of lignite is part of the alliance ibi (innovative Braunkohlenintegration) to use lignite as a raw material to produce chemicals. With this new one step process without an input of external hydrogen, mostly propylene, butenes and aromatics and char are formed. The product yield depends on manifold process parameters. The use of acid catalysts (zeolites like MFI) shows the highest amount of the desired products. Hydrogen rich lignites with a molar H/C ratio of > 1 are to be favoured. Due to primary cracking and secondary reactions the ratio between catalyst and lignite, temperature and residence time are the most important parameter to control the product distribution. Experiments at 500 C in a discontinuous rotary kiln reactor show yields up to 32 wt-% of hydrocarbons per lignite (maf - moisture and ash free) and 43 wt-% char, which can be gasified. Particularly, the yields of propylene and butenes as main products can be enhanced four times to about 8 wt-% by the use of catalysts while the tar yield decreases. In order to develop this innovative process catalyst systems fixed on beads were developed for an easy separation and regeneration of the used catalyst from the formed char. (orig.)

  20. Immigration process in catalytic medium

    Institute of Scientific and Technical Information of China (English)

    洪文明; 王梓坤

    2000-01-01

    The longtime behavior of the immigration process associated with a catalytic super-Brown-ian motion is studied. A large number law is proved in dimension d≤3 and a central limit theorem is proved for dimension d = 3.

  1. Immigration process in catalytic medium

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The longtime behavior of the immigration process associated with a catalytic super-Brownian motion is studied. A large number law is proved in dimension d≤3 and a central limit theorem is proved for dimension d=3.

  2. Post-treatment of refinery wastewater effluent using a combination of AOPs (H2O2 photolysis and catalytic wet peroxide oxidation) for possible water reuse. Comparison of low and medium pressure lamp performance.

    Science.gov (United States)

    Rueda-Márquez, J J; Levchuk, I; Salcedo, I; Acevedo-Merino, A; Manzano, M A

    2016-03-15

    The main aim of this work was to study the feasibility of multi-barrier treatment (MBT) consisting of filtration, hydrogen peroxide photolysis (H2O2/UVC) and catalytic wet peroxide oxidation (CWPO) for post-treatment of petroleum refinery effluent. Also the possibility of water reuse or safe discharge was considered. The performance of MBT using medium (MP) and low (LP) pressure lamps was compared as well as operation and maintenance (O&M) cost. Decomposition of organic compounds was followed by means of gas chromatography-mass spectrometry (GC-MS), total organic carbon (TOC) and chemical oxygen demand (COD) analysis. After filtration step (25 μm) turbidity and concentration of suspended solids decreased by 92% and 80%, respectively. During H2O2/UVC process with LP lamp at optimal conditions (H2O2:TOC ratio 8 and UVC dose received by water 5.28 WUVC s cm(-2)) removal of phenolic compounds, TOC and COD was 100%, 52.3% and 84.3%, respectively. Complete elimination of phenolic compounds, 47.6% of TOC and 91% of COD was achieved during H2O2/UVC process with MP lamp at optimal conditions (H2O2:TOC ratio 5, UVC dose received by water 6.57 WUVC s cm(-2)). In order to compare performance of H2O2/UVC treatment with different experimental set up, the UVC dose required for removal of mg L(-1) of COD was suggested as a parameter and successfully applied. The hydrophilicity of H2O2/UVC effluent significantly increased which in turn enhanced the oxidation of organic compounds during CWPO step. After H2O2/UVC treatment with LP and MP lamps residual H2O2 concentration was 160 mg L(-1) and 96.5 mg L(-1), respectively. Remaining H2O2 was fully consumed during subsequent CWPO step (6 and 3.5 min of contact time for LP and MP, respectively). Total TOC and COD removal after MBT was 94.7% and 92.2% (using LP lamp) and 89.6% and 95%, (using MP lamp), respectively. The O&M cost for MBT with LP lamp was estimated to be 0.44 € m(-3) while with MP lamp it was nearly five

  3. Reduction of nitrate from groundwater: powder catalysts and catalytic membrane.

    Science.gov (United States)

    Chen, Ying-Xu; Zhang, Yan; Liu, Hong-Yuan

    2003-09-01

    The reduction of nitrate contaminant in groundwater has gained renewed and intensive attention due to the environmental problems and health risks. Catalytic denetrification presents one of the most promising approaches for the removal of nitrate from water. Catalytic nitrate reduction from water by powder catalysts and catalytic membrane in a batch reactor was studied. And the effects of the initial concentration, the amounts of catalyst, and the flux H2 on the nitrate reduction were also discussed. The results demonstrated that nitrate reduction activity and the selectivity to nitrogen gas were mainly controlled by diffusion limitations and the mass transfer of the reactants. The selectivity can improved while retaining a high catalytic activity under controlled diffusion condition or the intensification of the mass transfer, and a good reaction condition. The total nitrogen removal efficiency reached above 80%. Moreover, catalytic membrane can create a high effective gas/liquid/solid interface, and show a good selectivity to nitrogen in comparative with the powder catalyst, the selectivity to nitrogen was improved from 73.4% to 89.4%.

  4. Reduction of nitrate from groundwater: powder catalysts and catalytic membrane

    Institute of Scientific and Technical Information of China (English)

    CHEN Ying-xu; ZHANG Yan; LIU Hong-yuan

    2003-01-01

    The reduction of nitrate contaminant in groundwater has gained renewed and intensive attention due to the environmental problems and health risks. Catalytic denetrification presents one of the most promising approaches for the removal of nitrate from water. Catalytic nitrate reduction from water by powder catalysts and catalytic membrane in a batch reactor was studied. And the effects of the initial concentration, the amounts of catalyst, and the flux H2 on the nitrate reduction were also discussed. The results demonstrated that nitrate reduction activity and the selectivity to nitrogen gas were mainly controlled by diffusion limitations and the mass transfer of the reactants. The selectivity can improved while retaining a high catalytic activity under controlled diffusion condition or the intensification of the mass transfer, and a good reaction condition. The total nitrogen removal efficiency reached above 80%. Moreover, catalytic membrane can create a high effective gas/liquid/solid interface, and show a good selectivity to nitrogen in comparative with the powder catalyst, the selectivity to nitrogen was improved from 73.4% to 89.4%.

  5. 油包水微乳液中抗体酶催化布洛芬酯选择性水解的酶学特性%Enzymological Characteristics of Catalytic Antibody-catalyzed enantioselective Hydrolysis of Ibuprofen Ester in Water-in-oil microemulsion

    Institute of Scientific and Technical Information of China (English)

    杨根生; 戚映丹; 欧志敏; 姚善泾

    2009-01-01

    The asymmetric hydrolyzation of racemic ibuprofen ester is one of the most important methods for chiral separation of ibuprofen. A catalytic antibody that accelerates the rate of enantioselective hydrolysis of ibuprofen methyl ester was successfully elicited against an immunogen consisting of tetrahedral sulfate hapten attached to bovine serum albumin (BSA). The rate constant enhancement factor Kcat/Kuncat was about 1.6x104. The catalytic activity of the catalytic antibody in a reverse micelle reaction system based on sodium b/s (2-ethylhexyl) sodium sulfosuccinate (AOT) in isooctane was studied. Kinetic analysis of the catalytic antibody-catalyzed reaction was found to be possible in this system. Kinetic studies showed that hydrolysis in the microemulsion system follow Michaelis-Menten kinetics. The catalytic antibody can also accelerate catalysis of S-ibuprofen methyl ester in the microemulsion system. Temperature effects, the pH profile, Km,app and Kcat were determined. The dependence of the catalytic antibody hydrolytic activity on the Wo (molar ratio of water to surfactant) showed a bell-shaped curve, presenting a maximum at about wo = 21.%根据过渡态理论设计和合成了能诱导产生催化选择性水解布洛芬甲酯的催化抗体的四面体硫酸盐半抗原,并与牛血清白蛋白(BSA)偶联制备成免疫源,通过免疫手段成功筛选出具有加速选择性水解生成S-布洛芬的特异性催化抗体.其Kcat,app/Kuncat,app达1.6x104.进一步地将催化抗体运用到W/O微乳体系(反胶束)中进行布洛芬酯的选择性水解研究,其动力学研究证明其催化过程同样遵循Michaelis.Menten方程.考察了pH值和温度对催化初速度影响,Wo(体系中水和琥珀酸二辛酯磺酸钠(AOT)的摩尔比)对催化初速度影响呈现为钟罩型,最适的Wo.为21.

  6. Clay Minerals as Solid Acids and Their Catalytic Properties.

    Science.gov (United States)

    Helsen, J.

    1982-01-01

    Discusses catalytic properties of clays, attributed to acidity of the clay surface. The formation of carbonium ions on montmorillonite is used as a demonstration of the presence of surface acidity, the enhanced dissociation of water molecules when polarized by cations, and the way the surface can interact with organic substances. (Author/JN)

  7. STUDY ON THE CATALYTIC ABILITY OF BIOACTIVE FIBERS

    Institute of Scientific and Technical Information of China (English)

    YAO Yuyuan; CHEN Wenxing

    2006-01-01

    Two kinds of water-soluble metallophthalocyanines (Mt2Pc2), binuclear cobalt phthalocyanine (Co2Pc2) and binuclear ferric phthalocyanine (Fe2Pc2), were supported on silk fibers and modified viscose fibers to construct bioactive fibers of mimic enzyme, Mt2Pc2 used as the active center of bioactive fibers, viscose and silk fibers as the microenvironments. The catalytic oxidation ability of bioactive fibers on the malodors of methanthiol and hydrogen sulfide was investigated at room temperature. The experimental results demonstrated that the catalytic activity of such bioactive fibers was tightly correlative to the types of bioactive fibers and substrates.

  8. Production of furfural from xylose, water-insoluble hemicelluloses and water-soluble fraction of corncob via a tin-loaded montmorillonite solid acid catalyst.

    Science.gov (United States)

    Li, Huiling; Ren, Junli; Zhong, Linjie; Sun, Runcang; Liang, Lei

    2015-01-01

    The conversion of xylose, water-insoluble hemicelluloses (WIH) and water-soluble fraction (WSF) of corncob to furfural was performed using montmorillonite with tin ions (Sn-MMT) containing double acid sites as a solid acid catalyst. The co-existence of Lewis acids and Brønsted acids in Sn-MMT was shown to improve the furfural yield and selectivity. 76.79% furfural yield and 82.45% furfural selectivity were obtained from xylose using Sn-MMT as a catalyst in a biphasic system with 2-s-butylphenol (SBP) as the organic extracting layer and dimethyl sulfoxide (DMSO) as the co-solvent in contact with an aqueous phase saturated with NaCl (SBP/NaCl-DMSO) at 180°C for 30min. Furthermore, Sn-MMT also demonstrated the excellent catalytic performance in the conversion of pentose-rich materials of corncob and 39.56% and 54.15% furfural yields can be directly obtained from WIH and WSF in the SBP/NaCl-DMSO system, respectively.

  9. 弹性成像评分联合超声造影鉴别桥本甲状腺炎背景下结节良恶性临床价值的研究%Clinical value of elastography scores combining with contrast-enhanced ultrasound in identifying benign and malignant thyroid nodules co-existed with Hashimoto′s thyroiditis

    Institute of Scientific and Technical Information of China (English)

    于风霞; 王建红; 王彦华; 李萍; 牛晓燕; 王宏桥

    2016-01-01

    分析160个桥本甲状腺炎背景下结节的弹性成像及超声造影特点。良、恶性结节的弹性成像评分及造影模式差异有统计学意义。弹性成像联合超声造影能较好地鉴别诊断桥本甲状腺炎背景下结节的良恶性。%[Summary] Elastographic and contrast-enhanced ultrasonographic features were reviewed in 160 thyroid nodules co-existed with Hashimoto's thyroiditis. Significant differences in the elastography scores and enhancement pattern were found between malignant and benign thyroid nodules. For the differential diagnosis of benign and malignant thyroid nodules co-existed with Hashimoto's thyroiditis, the combined scores of elastography scores and contrast-enhanced ultrasound features may offer greater values.

  10. 水环境中共存重金属对不同固相物质吸附镉和铜的影响%Influence of Co-existing Heavy Metals on the Adsorption of Cadmium and Copper onto Different Types of Solid Materials in Aquatic System

    Institute of Scientific and Technical Information of China (English)

    董会军; 花修艺; 贺丽; 董德明; 徐志璐; 梁大鹏; 郭志勇

    2012-01-01

    利用采集的固相物质(生物膜、悬浮颗粒物和沉积物)模拟水环境中多种固相物质共存吸附体系,研究共存金属对固相物质吸附镉和铜的影响.结果表明,各固相物质对镉的吸附均受共存金属(铜和铅)的抑制作用.当悬浮颗粒物吸附镉时,铜和铅的浓度增大,对镉吸附的抑制程度增强;当生物膜和沉积物吸附镉时,铅浓度的增加使得铅抑制镉的吸附作用增强,不同浓度的铜对镉吸附作用的抑制程度差别较小.共存铅对铜吸附有抑制作用,当铅浓度增加时,3种固相物质吸附铜所受的抑制作用均增强,而共存镉对铜的吸附影响较小.即在重金属总浓度较低时,重金属间的相互影响较小;随着重金属总浓度的增加,重金属间的相互影响增强.共存金属浓度变化对悬浮颗粒物吸附铜和镉受到的抑制程度影响较大,共存金属浓度越大,共存金属对悬浮颗粒物吸附镉和铜的抑制作用越强.%The influence of co-existing heavy metals on the adsorption of cadmium and copper onto solid phases was investigated by simulating aquatic multi-phase system comprising three types of solid phases, including biofilms, suspended paniculate materials and sediments, in the absence and presence of co-existing heavy metals. The results indicate that co-existing metals ( copper and lead) reduced the adsorption of cadmium to all solid phases remarkably. Under the conditions of the adsorption of cadmium onto suspended particulate materials, the reduction effects increased as the initial concentration of copper and lead increased. Under the conditions of the adsorption of cadmium to hiofilm and sediments, increasing lead initial concentra- tion enhanced the reduction effects on cadmium adsorption, but increasing copper initial concentration had little influence on the reduction effects. The co-existing lead reduced the adsorption of copper to solid materials and these reduction effects increased with

  11. Effect of water vapor on the CO and CH_4 catalytic oxidation over CeO_2-MO_x (M=Cu, Mn, Fe, Co, and Ni) mixed oxide

    Institute of Scientific and Technical Information of China (English)

    乔东升; 卢冠忠; 郭耘; 王艳芹; 郭杨龙

    2010-01-01

    CeO2-MOx (M=Cu, Mn, Fe, Co, and Ni) mixed oxide catalysts were prepared by a citric acid complexation-combustion method. CeO2-MOx solid solutions could be formed with M cations doping into CeO2 lattice, while NiO and Co3O4 phases were detected on the surface of CeO2-NiO and CeO2-Co3O4 by Raman spectroscopy. The presence of M in CeO2 could obviously promote its catalytic activity for CH4 catalytic combustion and CO oxidation. Among the prepared samples, CeO2-CuO exhibited the best performance for CO oxidatio...

  12. Achillea millefolium L. extract mediated green synthesis of waste peach kernel shell supported silver nanoparticles: Application of the nanoparticles for catalytic reduction of a variety of dyes in water.

    Science.gov (United States)

    Khodadadi, Bahar; Bordbar, Maryam; Nasrollahzadeh, Mahmoud

    2017-05-01

    In this paper, silver nanoparticles (Ag NPs) are synthesized using Achillea millefolium L. extract as reducing and stabilizing agents and peach kernel shell as an environmentally benign support. FT-IR spectroscopy, UV-Vis spectroscopy, X-ray Diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDS), Thermo gravimetric-differential thermal analysis (TG-DTA) and Transmission Electron Microscopy (TEM) were used to characterize peach kernel shell, Ag NPs, and Ag NPs/peach kernel shell. The catalytic activity of the Ag NPs/peach kernel shell was investigated for the reduction of 4-nitrophenol (4-NP), Methyl Orange (MO), and Methylene Blue (MB) at room temperature. Ag NPs/peach kernel shell was found to be a highly active catalyst. In addition, Ag NPs/peach kernel shell can be recovered and reused several times with no significant loss of its catalytic activity.

  13. Catalytic Hydrothermal Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.

    2015-05-31

    The term “hydrothermal” used here refers to the processing of biomass in water slurries at elevated temperature and pressure to facilitate the chemical conversion of the organic structures in biomass into useful fuels. The process is meant to provide a means for treating wet biomass materials without drying and to access ionic reaction conditions by maintaining a liquid water processing medium. Typical hydrothermal processing conditions are 523-647K of temperature and operating pressures from 4-22 MPa of pressure. The temperature is sufficient to initiate pyrolytic mechanisms in the biopolymers while the pressure is sufficient to maintain a liquid water processing phase. Hydrothermal gasification is accomplished at the upper end of the process temperature range. It can be considered an extension of the hydrothermal liquefaction mechanisms that begin at the lowest hydrothermal conditions with subsequent decomposition of biopolymer fragments formed in liquefaction to smaller molecules and eventually to gas. Typically, hydrothermal gasification requires an active catalyst to accomplish reasonable rates of gas formation from biomass.

  14. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    Vivek V Ranade

    2014-03-01

    Catalytic reactions are ubiquitous in chemical and allied industries. A homogeneous or heterogeneous catalyst which provides an alternative route of reaction with lower activation energy and better control on selectivity can make substantial impact on process viability and economics. Extensive studies have been conducted to establish sound basis for design and engineering of reactors for practising such catalytic reactions and for realizing improvements in reactor performance. In this article, application of recent (and not so recent) developments in engineering reactors for catalytic reactions is discussed. Some examples where performance enhancement was realized by catalyst design, appropriate choice of reactor, better injection and dispersion strategies and recent advances in process intensification/ multifunctional reactors are discussed to illustrate the approach.

  15. Catalytic activity of Au nanoparticles

    DEFF Research Database (Denmark)

    Larsen, Britt Hvolbæk; Janssens, Ton V.W.; Clausen, Bjerne;

    2007-01-01

    Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change with par......Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change...... with particle size. We find that the fraction of low-coordinated Au atoms scales approximately with the catalytic activity, suggesting that atoms on the corners and edges of Au nanoparticles are the active sites. This effect is explained using density functional calculations....

  16. Catalytically and noncatalytically treated automobile exhaust: biological effects in rats

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, G.P. (Univ. of Cincinnati); Lewkowski, J.P.; Hastings, L.; Malanchuk, M.

    1977-12-01

    Chronic exposure to catalytically treated or noncatalytically treated automobile exhaust significantly depressed the spontaneous locomotor activity (SLA) of rats. Exposure to H/sub 2/SO/sub 4/ alone or CO at comparable levels did not alter the SLA. Exposure to noncatalytically treated exhaust resulted in significant reductions in growth rate and food and water intake. However, these effects were not evident in the exposure to catalytically treated exhaust or in the control H/sub 2/SO/sub 4/ and CO exposures. Blood acid-base analyses indicated that exposure to either catalytically treated exhaust or H/sub 2/SO/sub 4/ elicits a metabolic alkalosis, while exposure to CO alone results in a metabolic acidosis. All acid-base parameters were within the normal range several weeks after the termination of exposure.

  17. Fe/Cu催化还原降解饮用水中溴氯乙腈的性能研究%Performance Study of Bromochloracetonitrile Degradation in Drinking Water by Fe/Cu Catalytic Reduction

    Institute of Scientific and Technical Information of China (English)

    丁春生; 马海龙; 傅洋平; 赵世督; 李东兵

    2015-01-01

    为了降低饮用水在氯消毒过程中产生的消毒副产物(DBPs)溴氯乙腈(BCAN)对人体带来的健康危害,采用 Fe/ Cu 催化还原的方法降解饮用水中低浓度的 BCAN,考察了 BCAN 的降解效果和其影响因素,探讨了其降解机制及动力学规律.结果表明,Fe/ Cu 具有更强的还原降解 BCAN 的能力,与零价铁相比, Fe/ Cu(质量比为10:1)的降解效率是其1.5倍.随着 Fe/ Cu 投加量的增加,BCAN 的去除率有明显的提高,对于初始浓度为20μg•L -1的 BCAN 溶液,当 Fe/ Cu(质量比为10:1)投加量由5 g•L -1增加到10 g•L -1,反应150 min 后,去除率由51.1%增加到89.5%. BCAN 降解效率随着温度的升高逐渐提高,BCAN 初始浓度的变化对 Fe/ Cu 去除 BCAN 的去除效果影响不大,Fe/ Cu 降解 BCAN 符合一级反应动力学规律.%The paper used the method of iron copper catalyst reduction to degrade low concentrations of bromochloracetonitrile (BCAN) to lighten the damage to human being, which is a kind of disinfection by-products (DBPs) produced during the chlorination process of drinking water. The removal efficiency of BCAN and its influencing factors were investigated. The mechanism of degradation and kinetics were also explored. The results indicated that iron copper had a greater degradation ability towards BCAN, and the degradation rate of iron copper (mass ratio of 10: 1) was 1. 5 times that of the zero-valent iron. The removal of BCAN increased obviously with the increase of Fe/ Cu dosage. When the initial concentration was set at 20 μg•L - 1 , after a reaction time of 150 min, removal of BCAN was improved from 51. 1% to 89. 5% with the increase of iron copper (mass ratio of 10: 1) dosage from 5 g•L - 1 to 10 g•L - 1 . The temperature also had great impact on BCAN removal and the removal increased with the increase of temperature. However, BCAN removal did not change a lot with the variation of the initial concentration of BCAN when it was at

  18. Catalytic Decoupling of Quantum Information

    DEFF Research Database (Denmark)

    Majenz, Christian; Berta, Mario; Dupuis, Frédéric

    2017-01-01

    The decoupling technique is a fundamental tool in quantum information theory with applications ranging from quantum thermodynamics to quantum many body physics to the study of black hole radiation. In this work we introduce the notion of catalytic decoupling, that is, decoupling in the presence...... of an uncorrelated ancilla system. This removes a restriction on the standard notion of decoupling, which becomes important for structureless resources, and yields a tight characterization in terms of the max-mutual information. Catalytic decoupling naturally unifies various tasks like the erasure of correlations...... and quantum state merging, and leads to a resource theory of decoupling....

  19. Comparison of drought strategies of three co-existing woody plants by their hydraulic structures%从水力结构比较3种共存木本植物的抗旱策略

    Institute of Scientific and Technical Information of China (English)

    靳欣; 徐洁; 白坤栋; 冯锦霞; 张劲松; 万贤崇

    2011-01-01

    通过盆栽控水方法测定了华北石质山区刺槐、栓皮栎和侧柏3个主要造林树种在干旱胁迫以及随后的复水条件下气体交换和水分关系的变化,分析了这3个树种抗旱特性的差异。结果表明:1)在供水充足时,刺槐光合作用强、气孔导度大、耗水速度快。2)刺槐对土壤水分变化最为敏感,当土壤水分含量降低时,其光合速率和气孔导度迅速下降。3)复水后,刺槐和栓皮栎恢复速度比侧柏快。4)当小枝导水损失率发生变化时,刺槐的气孔导度变化迅速,相比之下,栓皮栎和侧柏对土壤水分变化以及其气孔导度随水力变化的反应都较为平缓。5)刺槐在水分充足时迅速进行光合积累,而干旱时,通过气孔关闭甚至落叶来避免过度失水。另外2种植物在中度干旱时,尤可保持光合作用,其中侧柏更为突出。在华北半干旱的石质山区,刺槐的发展受到较大限制。%This paper investigates the physiological characteristics for drought resistance among three main afforestation woody species(ie Robinia pseudoacacia L.,Quercus variabilis Blume,Platycladus orientalis(L.) Franco) in lithoid mountainous areas in north China.Variations in their gas exchanges and water relations were comparatively measured during withholding water and subsequent rewatering of potted seedlings.The results showed that:1) under well-watered conditions,black locust(R.pseudoacacia) had the strongest photosynthesis,the greatest stomatal conductance and water consumption among the three species.2) However,black locust was most sensitive to soil drying among the three species,its photosynthesis and stomatal conductance rapidly declined.3) On being rewatered,both gas exchanges and water relations were able to be rapidly recovered in all three species,among which black locust and cork oak(Q.variabilis) had faster recovery than arborvitae(P.orientalis).4) Stomatal

  20. Simple, chemoselective, catalytic olefin isomerization.

    Science.gov (United States)

    Crossley, Steven W M; Barabé, Francis; Shenvi, Ryan A

    2014-12-01

    Catalytic amounts of Co(Sal(tBu,tBu))Cl and organosilane irreversibly isomerize terminal alkenes by one position. The same catalysts effect cycloisomerization of dienes and retrocycloisomerization of strained rings. Strong Lewis bases like amines and imidazoles, and labile functionalities like epoxides, are tolerated.

  1. Catalytic Asymmetric Bromocyclization of Polyenes.

    Science.gov (United States)

    Samanta, Ramesh C; Yamamoto, Hisashi

    2017-02-01

    The first catalytic asymmetric bromonium ion-induced polyene cyclization has been achieved by using a chiral BINOL-derived thiophosphoramide catalyst and 1,3-dibromo-5,5-dimethylhydantoin as an electrophilic bromine source. Bromocyclization products are obtained in high yields, with good enantiomeric ratios and high diastereoselectivity, and are abundantly found as scaffolds in natural products.

  2. Effect of ions in water on the catalytic ozonation by pumice supported zinc%水中常见离子对锌改性浮石催化臭氧化有机物效能的影响

    Institute of Scientific and Technical Information of China (English)

    袁磊; 杨帆; 倪红伟

    2015-01-01

    采用锌改性浮石为催化剂,催化臭氧氧化难降解的硝基类卤代芳香族有机化合物-对氯硝基苯,对水中常见无机离子对催化臭氧氧化去除水中微量对氯硝基苯的效能进行了比较。实验结果表明,水中阳离子Na+和 K+对去除效能影响较小,Ca2+和 Mg2+对去除效能略有促进作用。阴离子对去除效能影响较为明显,均有一定抑制作用,NO3-和Cl-影响不明显,其中以SO42-和PO43-的抑制影响最大。%The catalytic ozonation of p-chloronitrobenzene (p-CNB) in an aqueous solution using modification pumice as the catalysts was investigated. The effects of NO3-, Na+, and K+ on the catalytic ozonation of p-CNB can be ignored. Degradation effi-ciency was slightly promoted in the presence of Ca2+ and Mg2+. The ozonation of p-CNB was slightly inhibited by the high con-centration of Cl-. The removal efficiency of p-CNB decreased in the presence of SO42-, given that the hydroxyl inhibitors PO43- can significantly inhibit the catalytic degradation of p-CNB.

  3. Water

    Science.gov (United States)

    Leopold, Luna Bergere; Baldwin, Helene L.

    1962-01-01

    What do you use water for?If someone asked you this question you would probably think right away of water for drinking. Then you would think of water for bathing, brushing teeth, flushing the toilet. Your list would get longer as you thought of water for cooking, washing the dishes, running the garbage grinder. Water for lawn watering, for play pools, for swimming pools, for washing the car and the dog. Water for washing machines and for air conditioning. You can hardly do without water for fun and pleasure—water for swimming, boating, fishing, water-skiing, and skin diving. In school or the public library, you need water to wash your hands, or to have a drink. If your home or school bursts into flames, quantities of water are needed to put it out.In fact, life to Americans is unthinkable without large supplies of fresh, clean water. If you give the matter a little thought, you will realize that people in many countries, even in our own, may suffer from disease and dirt simply because their homes are not equipped with running water. Imagine your own town if for some reason - an explosion, perhaps - water service were cut off for a week or several weeks. You would have to drive or walk to a neighboring town and bring water back in pails. Certainly if people had to carry water themselves they might not be inclined to bathe very often; washing clothes would be a real chore.Nothing can live without water. The earth is covered by water over three-fourths of its surface - water as a liquid in rivers, lakes and oceans, and water as ice and snow on the tops of high mountains and in the polar regions. Only one-quarter of our bodies is bone and muscle; the other three-fourths is made of water. We need water to live, and so do plants and animals. People and animals can live a long time without food, but without water they die in a few days. Without water, everything would die, and the world would turn into a huge desert.

  4. Comparison between a Water-Based and a Solvent-Based Impregnation Method towards Dispersed CuO/SBA-15 Catalysts: Texture, Structure and Catalytic Performance in Automotive Exhaust Gas Abatement

    Directory of Open Access Journals (Sweden)

    Qi Xin

    2016-10-01

    Full Text Available Supported copper oxide nanoparticles are a potential candidate for replacing the rare and expensive precious metals within the automotive three-way catalyst. However, a well-designed dispersion method is necessary to allow a stable high loading of active material, compensating its lower intrinsic activity and stability. In this work, a CuO-loaded SBA-15 catalyst has been manufactured by two methods. The ammonia-driven deposition precipitation (ADP and the molecular designed dispersion (MDD methods are both considered as efficient deposition methods to provide well-dispersed copper oxide-based catalysts. Their morphology, copper dispersion and the chemical state of copper were characterized and compared. Due to the differences in the synthesis approach, a difference in the obtained copper oxide phases has been observed, leading to a distinct behavior in the catalytic performance. The structure-activity correlation of both catalysts has also been revealed for automotive exhaust gas abatement. Results demonstrate that various copper species can be formed depending on the precursor–support interaction, affecting selectivity and conversion during the catalytic reaction.

  5. Water

    Science.gov (United States)

    ... Lead Poisoning Prevention Training Center (HHLPPTC) Training Tracks Water Language: English Español (Spanish) Recommend on Facebook Tweet Share Compartir For information about lead in water in Flint, MI, please visit http://www.phe. ...

  6. Synthesis and application of iron and zinc doped biochar for removal of p-nitrophenol in wastewater and assessment of the influence of co-existed Pb(II)

    Science.gov (United States)

    Wang, Pei; Tang, Lin; Wei, Xue; Zeng, Guangming; Zhou, Yaoyu; Deng, Yaocheng; Wang, Jingjing; Xie, Zhihong; Fang, Wei

    2017-01-01

    The modification of biochar as a low-cost adsorbent is essential to improve its surface properties and shows great potential in water decontamination. The iron and zinc doped sawdust biochar (Fe/Zn-biochar) with large apparent surface area (518.54 m2/g) proposed in this work showed good performance for p-nitrophenol (PNP) removal compared with the pristine biochar (P-biochar), iron doped biochar (Fe-biochar) and zinc doped biochar (Zn-biochar) respectively. The batch experiments turned out that Fe/Zn-biochar exhibited larger PNP adsorption capacity under acidic pH solution, and the ionic strength had slightly negative impact on PNP adsorption. The adsorption kinetics and isotherms were discussed, and the experimental data fitted well the Pseudo-second-order equation and Langmuir model. The thermodynamic study indicated that the PNP adsorption was a spontaneous endothermic process. Furthermore, the simultaneous removal for PNP and Pb(II) by Fe/Zn-biochar was investigated. It implied that the adsorption of PNP and Pb(II) at their low concentration might be enhanced by the complexing-bridging mechanism of PNP and Pb(II) ascribing to the affinity between PNP and hydrophobic sites, in addition to the affinity between Pb(II) and oxygen-containing hydrophilic sites on Fe/Zn-biochar surface. However, the predominated competition between PNP and Pb(II) at their high concentrations with Fe/Zn-biochar suppressed their adsorption.

  7. Template electrodeposition of catalytic nanomotors.

    Science.gov (United States)

    Wang, Joseph

    2013-01-01

    The combination of nanomaterials with electrode materials has opened new horizons in electroanalytical chemistry, and in electrochemistry in general. Over the past two decades we have witnessed an enormous activity aimed at designing new electrochemical devices based on nanoparticles, nanotubes or nanowires, and towards the use of electrochemical routes--particularly template-assisted electrodeposition--for preparing nanostructured materials. The power of template-assisted electrochemical synthesis is demonstrated in this article towards the preparation and the realization of self-propelled catalytic nanomotors, ranging from Pt-Au nanowire motors to polymer/Pt microtube engines. Design considerations affecting the propulsion behavior of such catalytic nanomotors are discussed along with recent bioanalytical and environmental applications. Despite recent major advances, artificial nanomotors have a low efficiency compared to their natural counterparts. Hopefully, the present Faraday Discussion will stimulate other electrochemistry teams to contribute to the fascinating area of artificial nanomachines.

  8. Radiation/Catalytic Augmented Combustion.

    Science.gov (United States)

    1980-09-01

    NATIO& NAk H(fJI At tl TANUAHTOb 19 A ~omm.81-0287 LVL RADIATION/CATALYTIC AUGMENTED COMBUST ION MOSHE LAVID CORPORATE RESEARCH-TECHNOLOGY FEASIBILITY...refinements as necessary. i. Perform cannular combustor experiments to Investigate ignition and flame attachment in flowing, liquid -fuel, unpremixed...stabilizer, with a sintered metal disk on the downstream side through which hot gases or products of partial fuel oxidation can be passed. Experimental

  9. Thermodynamics of catalytic nanoparticle morphology

    Science.gov (United States)

    Zwolak, Michael; Sharma, Renu; Lin, Pin Ann

    Metallic nanoparticles are an important class of industrial catalysts. The variability of their properties and the environment in which they act, from their chemical nature & surface modification to their dispersion and support, allows their performance to be optimized for many chemical processes useful in, e.g., energy applications and other areas. Their large surface area to volume ratio, as well as varying sizes and faceting, in particular, makes them an efficient source for catalytically active sites. These characteristics of nanoparticles - i.e., their morphology - can often display intriguing behavior as a catalytic process progresses. We develop a thermodynamic model of nanoparticle morphology, one that captures the competition of surface energy with other interactions, to predict structural changes during catalytic processes. Comparing the model to environmental transmission electron microscope images of nickel nanoparticles during carbon nanotube (and other product) growth demonstrates that nickel deformation in response to the nanotube growth is due to a favorable interaction with carbon. Moreover, this deformation is halted due to insufficient volume of the particles. We will discuss the factors that influence morphology and also how the model can be used to extract interaction strengths from experimental observations.

  10. Catalytic polarographic currents of oxidizers

    Energy Technology Data Exchange (ETDEWEB)

    Zajtsev, P.M.; Zhdanov, S.I.; Nikolaeva, T.D. (Vsesoyuznyj Nauchno-Issledovatel' skij Inst. Khimicheskikh Reaktivov i Osobo Chistykh Veshchestv, Moscow (USSR))

    1982-06-01

    The state of theory and practice of an important direction in polarography, i.e. catalytic currents of oxidizers-substrates that have found a wide application in the development of highly sensitive methods of determination of a large number of substrates, catalysts and polarographically nonactive ligands, is considered. Transition and some non-transition elements serve as catalysts of reactions that cause catalytic polarographic currents of substrates. Catalytic activity of an inorganic catalyst increases with the increase in the number of its d-orbit. Complex formation in most cases leads to the increase of catalyst activity, however, sometimes a reverse phenomenon takes place. For many catalysts the maximum activity is observed at pH values close to pK value of their hydrolysis. The properties of oxidizers-substrates is revealed by H/sub 2/O/sub 2/, ClO/sub 3//sup -/, BrO/sub 3//sup -/, IO/sub 3//sup -/, ClO/sub 4//sup -/, IO/sub 4//sup -/, NO/sub 2//sup -/, NO/sub 3//sup -/, NH/sub 2/OH, V(5), V(4), S/sub 2/O/sub 8//sup 2 -/, H/sub 2/SO/sub 4/, H/sub 2/C/sub 2/O/sub 4/, COHCOOH, alkenes compounds, organic halogen , sulfur- and amine-containing compounds.

  11. Catalytic Potential of Nano-Magnesium Oxide on Degradation of Humic Acids From Aquatic Solutions

    Directory of Open Access Journals (Sweden)

    Ghorban Asgari

    2014-12-01

    Full Text Available Catalytic ozonation is a new and promising process used to remove the contaminants from drinking water and wastewater. This study aimed to evaluate the catalytic potential of nano-magnesium oxide (nano-MgO for the removal of humic acids (HA from water. Mg (NO32 solution was used to prepare MgO powder by the calcination method. In a semi-batch reactor, the catalytic ozonation was carried out. The effects of the various operating parameters, including pH, reaction time, T-butyl alcohol (TBA and phosphate on HA degradation were evaluated. Experimental results indicated that degradation of HA was increased as the pH solution and reaction time were increased. Maximum HA degradation was obtained at pH = 10 and the reaction time of 10 minutes in the catalytic process. The calculated catalytic potential of nano-MgO on ozonation of HA was 60%. Moreover, catalytic ozonation process was not affected by TBA and the main reaction on HA degradation HA have effect take place on MgO surface. According to the results of this study, the developed MgO catalyst is the active and proficient catalyst in HA degradation using the catalytic ozonation process.

  12. Flow Injection Determination of Oxalate Based on Its Catalytic Effect on the Oxidation of p-Chloride Aniline by Dichromate

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In a sulfuric acid medium, oxalate exhibits a strong catalytic effect on the oxidation of p-chloride aniline (ClBN) by dichromate, and the red oxidation product of ClBN has a maximum absorbancy at 520 nm. Based on this founding, a new FI method for determining oxalate was developed. A calibration curve of oxalate in the range of 0. 40-17.0 tg/mL was obtained. The detection limit was 0. 10 μg/mL. Sampling rate was 103-samples/h. The possible interference by the co-existing substances or ions was examined. This new method was applied to the determination of micro amounts of oxalate in real samples with satisfactory results.

  13. Performance of a Novel Hydrophobic Mesoporous Material for High Temperature Catalytic Oxidation of Naphthalene

    Directory of Open Access Journals (Sweden)

    Guotao Zhao

    2014-01-01

    Full Text Available A high surface area, hydrophobic mesoporous material, MFS, has been successfully synthesized by a hydrothermal synthesis method using a perfluorinated surfactant, SURFLON S-386, as the single template. N2 adsorption and TEM were employed to characterize the pore structure and morphology of MFS. Static water adsorption test indicates that the hydrophobicity of MFS is significantly higher than that of MCM-41. XPS and Py-GC/MS analysis confirmed the existence of perfluoroalkyl groups in MFS which led to its high hydrophobicity. MFS was used as a support for CuO in experiments of catalytic combustion of naphthalene, where it showed a significant advantage over MCM-41 and ZSM-5. SEM was helpful in understanding why CuO-MFS performed so well in the catalytic combustion of naphthalene. Experimental results indicated that MFS was a suitable support for catalytic combustion of large molecular organic compounds, especially for some high temperature catalytic reactions when water vapor was present.

  14. Catalytic pyrolysis of Pubescens to phenols over Ni/C catalyst

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The pyrolysis of Pubescens over Ni/C catalyst was studied at 350°C in H2 flow.The presence of Ni/C catalyst efficiently improved the degradation of raw materials,and produced bio-oil with high content of phenols but low contents of acetic acid,furfural and water.In the reaction,Ni/C catalyst plays the role of catalytic decomposition and catalytic hydrogenation.The existence of the carbon carrier favors the formation of active Ni in small sizes with more defects,which results in high catalytic activity of Ni in biomass decomposition and selective production of phenols.

  15. Cerium: catalytic properties, technological and environmental applications; Cerio: propriedades cataliticas, aplicacoes tecnologicas e ambientais

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Tereza S. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Fisica; Hewer, Thiago L.R. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Quimica; Freire, Renato S. [Universidade de Sao Paulo (USP), Cubatao (Brazil). Centro de Capacitacao e Pesquisa em Meio Ambiente]. E-mail: tmartins@if.usp.br

    2007-07-01

    Cerium based-compounds have great importance in a wide range of technological applications, such as: fuel cell devices development; metallurgic processes, petroleum refining; glass and ceramic production. Recently, its catalytic properties have been also explored for environmental applications, especially those to prevent or to control atmospheric and water pollution. Subjects covered in this work include a brief description of the fundaments of cerium catalytic properties and some relevant technological applications. Special attention is given to its photo catalytic activity and its ability to degrade pollutants. Recent results and future prospect about these applications are also evaluated. (author)

  16. Mg2+ coordination in catalytic sites of F1-ATPase.

    Science.gov (United States)

    Weber, J; Hammond, S T; Wilke-Mounts, S; Senior, A E

    1998-01-13

    Coordination of the Mg2+ ion in Mg-nucleotide substrates by amino acid residue side chains in the catalytic site of Escherichia coli F1-ATPase was investigated. From the X-ray structure of the mitochondrial enzyme [Abrahams, J. P., Leslie, A. G. W., Lutter, R., and Walker, J. E. (1994) Nature 370, 621-628], it may be inferred that the hydroxyl of betaThr-156 is a direct ligand of Mg2+, whereas the carboxyls of betaGlu-181, betaGlu-185, and betaAsp-242 might contribute via intervening water molecules. Elimination of each respective functional group by site-directed mutagenesis, followed by determination of Mg-nucleotide and uncomplexed nucleotide binding affinities using a tryptophan probe, showed that betaThr-156, betaGlu-185, and betaAsp-242 are all involved in Mg2+ coordination, whereas betaGlu-181 is not. A derived structural model for the octahedral coordination around the Mg2+ ion is presented. The results indicate that the ADP-containing site in the X-ray structure is the catalytic site of highest affinity. Correct Mg2+ coordination is required for catalytic activity at physiological rates. Elimination of any one of the Mg2+-coordinating residues led to complete loss of Mg2+-dependent nucleotide binding cooperativity of the catalytic sites.

  17. Kinetics of heterogeneous catalytic reactions

    CERN Document Server

    Boudart, Michel

    2014-01-01

    This book is a critical account of the principles of the kinetics of heterogeneous catalytic reactions in the light of recent developments in surface science and catalysis science. Originally published in 1984. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase acc

  18. Molecular catalytic coal liquid conversion

    Energy Technology Data Exchange (ETDEWEB)

    Stock, L.M.; Yang, Shiyong [Univ. of Chicago, IL (United States)

    1995-12-31

    This research, which is relevant to the development of new catalytic systems for the improvement of the quality of coal liquids by the addition of dihydrogen, is divided into two tasks. Task 1 centers on the activation of dihydrogen by molecular basic reagents such as hydroxide ion to convert it into a reactive adduct (OH{center_dot}H{sub 2}){sup {minus}} that can reduce organic molecules. Such species should be robust withstanding severe conditions and chemical poisons. Task 2 is focused on an entirely different approach that exploits molecular catalysts, derived from organometallic compounds that are capable of reducing monocyclic aromatic compounds under very mild conditions. Accomplishments and conclusions are discussed.

  19. Some Aspects of the Catalytic Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    Anil; K.Saikia

    2007-01-01

    1 Results Catalytic reactions are gaining importance due to its low cost, operational simplicity, high efficiency and selectivity. It is also getting much attention in green synthesis. Many useful organic reactions, including the acylation of alcohols and aldehydes, carbon-carbon, carbon-nitrogen, carbon-sulfur bond forming and oxidation reactions are carried out by catalyst. We are exploring the catalytic acylation of alcohols and aldehydes in a simple and efficient manner. Catalytic activation of unr...

  20. Supercritical water

    CERN Document Server

    Marcus, Yizhak

    2012-01-01

    Discover the many new and emerging applications of supercritical water as a green solvent Drawing from thousands of original research articles, this book reviews and summarizes what is currently known about the properties and uses of supercritical water. In particular, it focuses on new and emerging applications of supercritical water as a green solvent, including the catalytic conversion of biomass into fuels and the oxidation of hazardous materials. Supercritical Water begins with an introduction that defines supercritical fluids in general. It then defines supercritical wa

  1. Catalytic microrotor driven by geometrical asymmetry

    Science.gov (United States)

    Yang, Mingcheng; Ripoll, Marisol; Chen, Ke

    2015-02-01

    An asymmetric gear with homogeneous surface properties is, here, presented as a prototype to fabricate catalytic microrotors. The driving torque arises from the diffusiophoretic effect induced by the concentration gradients generated by catalytic chemical reactions at the gear surface. This torque produces a spontaneous and unidirectional rotation of the asymmetric gear. By means of mesoscopic simulations, we prove and characterize this scenario. The gear rotational velocity is determined by the gear-solvent interactions, the gear geometry, the solvent viscosity, and the catalytic reaction ratio. Our work presents a simple way to design self-propelled microrotors, alternative to existing catalytic bi-component, or thermophoretic ones.

  2. Nanostructured Catalytic Reactors for Air Purification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I project proposes the development of lightweight compact nanostructured catalytic reactors for air purification from toxic gaseous organic...

  3. Nanostructured Catalytic Reactors for Air Purification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase II project proposes the development of lightweight compact nanostructured catalytic reactors for air purification from toxic gaseous organic...

  4. Fabrication of MgAl2Si2O8 : M0.01 (M = Ni2+, Cu2+, Pd2+, Pt2+ and Ru3+): catalytic effects for the reduction of 2- or 4-nitroanilines in water

    Indian Academy of Sciences (India)

    Serkan Dayan; Sevgi Öztürk; Nilgün Kayaci; Nilgun Kalaycioglu Ozpozan; Esra Öztürk

    2015-10-01

    Five new MgAl2Si2O8 : M0.01 (M = Ni2+, Cu2+, Pd2+, Pt2+ and Ru3+) materials were developed for the reduction of nitroarenes as catalysts by conventional solid state reaction at 1300°C. The prepared materials were characterized by thermal analysis, Fourier transform infrared spectroscopy, X-ray powder diffraction analysis, scanning electron microscopy, energy-dispersive X-ray analysis and nitrogen adsorption–desorption analysis. The catalytic activities of the prepared catalysts were tested in the reduction of 2- or 4-nitroanilines in aqueous media at ambient temperature in the presence of NaBH4 by UV–vis spectrophotometer. Furthermore, the MgAl2Si2O8 : M0.01 catalysts can be recovered by filtration and reused for five cycles for the reduction of 2-nitroaniline. These results show that the MgAl2Si2O8 : M0.01 catalysts can be used in practical applications in the reduction of nitroanilines.

  5. Shape Co-Existence in the Transitional Nuclide 157Yb

    Institute of Scientific and Technical Information of China (English)

    徐川; 华辉; 李湘庆; 张双全; 许甫荣; 石跃; 竺礼华; 吴晓光; 李广生; 贺创业

    2012-01-01

    High-spin states in 157Yb have been populated in the 144Sm(160, 3n)157yb fusion- evaporation reaction at a beam energy of 85 MeV, and two rotational bands have been established for the first time. Within the framework of the triaxial particle-rotor model, the energy spectra and single-particle configurations of 157Yb are investigated. The calculated energy spectra agree well with the experimental data. The newly observed vf7/2 band, and the previously known vi13/2 band in 157Yb, are also discussed by means of Total-Routhian-Surface methods. The structural characters observed in 157Yb provide evidence for the shape coexistence of three distinct shapes: prolate, triaxial and oblate. At higher spins, both the vf7/2 band and the vi13/2 band in 157Yb undergo a shape evolution with sizable alignments occurring.

  6. Waste management and quality assurance: Reasonable co-existence?

    Energy Technology Data Exchange (ETDEWEB)

    Bresson, J.F.

    1989-11-01

    Implementing Chapter 3, Low-Level Waste Management, of DOE Order 5820-2, ``Radioactive Waste Management`` has created a major change in the operating philosophy of DOE`s prime contractors. So has the decision of May 1, 1987, when it was made clear that EPA has regulatory authority over DOE`s mixed waste. Suddenly two additional items became clear. First, DOE and its contractors were going to learn more about composition of low-level and low-level mixed waste than ever before. Second, low-level waste management was about to become a more focused, formal program, complete with needs for: (1) waste form identification, (2) program documentation; and (3) assurance that DOE`s waste does in fact comply with applicable requirements. The importance of the above items is clearly emphasized by the inclusion of Data Quality Objectives in the Waste Acceptance Criteria section of DOE 5820-2 Chapter 3 guidance called Data Quality Objectives, (DQO). Simply put, the purpose of the DQO is to identify the quality (and quantity) of information necessary to convince a regulator or decision maker that enough is known about DOE`s low-level and low-level mixed waste to allow safe disposal. The main objectives of the DOE and EPA shallow land burial requirements are to: (1) generate, with documented evidence, waste forms which are chemically inert and immobile, such that the waste will not tend to move about in the disposal medium; (2) select a disposal medium which would not let the wastes move about anyway; and (3) build some barriers around the wastes as emplaced in burial grounds, to provide additional assurance that buried wastes will stay in place. Compliance with these requirements must be demonstrated by quality data which describes the entire series of compliance activities.

  7. Autoimmune Diseases Co-Existing with Hepatitis C Virus Infection

    Directory of Open Access Journals (Sweden)

    Zohreh Jadali

    2010-12-01

    Full Text Available Autoimmunity and viral infections are closely associated fields, and viruses have been proposed as a likely aetiological, contributory or triggering factors of systemic autoimmune diseases. Hepatitis C virus seems to be the virus usually associated with the appearance of autoimmune diseases, and the relationship between chronic hepatitis C virus infection and some autoimmune disease has been studied. For some of these disorders their association with hepatitis C virus infection is well recognized while for others it remains probable or weak. Examples of autoimmune phenomena observed in chronic hepatitis C virus infection include rheumatoid arthritis, thyroid disease, cryoglobulinaemia, immune thrombocytopenic purpura, systemic lupus erythematosus and sjogren syndrome. To date, the etiological role and the pathogenetic involvement of the hepatitis C infection remains unknown.The aim of this study is to assess the presence of different autoimmune manifestations of hepatitis C virus infection reported in literature.

  8. Molar Pregnancy with a Co-Existing Viable Fetus

    Directory of Open Access Journals (Sweden)

    Ruya Deveer

    2014-03-01

    Full Text Available     The aim of this study was to report the clinical features, management, and outcome of a case of molar pregnancy with a coexisting viable fetus and to review the literature. In this article, we report a case of pregnancy with diffuse placental molar change and a normal fetus which presented with hyperemesis gravidarum and hyperthyroidism. Genetic amniocentesis showed normal fetal karyotype. A healthy full-term live male infant was delivered by cesarean section. In molar pregnancies with a normal karyotype fetus, with intensive maternal follow-up, continuation of pregnancy can be suggested.

  9. Co-existence of lip and epiglottis Kimura's disease.

    Science.gov (United States)

    Fatani, Hanadi A; Al-Mutrafi, Amna; Al-Qahtani, Khalid H; Tunio, Mutahir A

    2015-10-01

    Kimura's disease is a rare, chronic inflammatory condition of unknown etiology; with a predilection in the head and neck region. However, the involvement of the lip and epiglottis is extremely rare, and poses a diagnostic challenge. Here, we report a case of a 32-year-old Saudi male presenting with lip mass and epiglottic swelling without any history of hoarse voice or airway compromise. Serology showed elevated immunoglobulin E levels, and histopathological examination of biopsied lesions revealed well-developed lymphoid follicles with eosinophilic infiltration confirming Kimura's disease. At the time of last follow-up, his condition was satisfactory without any signs of recurrence.

  10. Three-Dimensional Structure and Catalytic Mechanism of Cytosine Deaminase

    Energy Technology Data Exchange (ETDEWEB)

    R Hall; A Fedorov; C Xu; E Fedorov; S Almo; F Raushel

    2011-12-31

    Cytosine deaminase (CDA) from E. coli is a member of the amidohydrolase superfamily. The structure of the zinc-activated enzyme was determined in the presence of phosphonocytosine, a mimic of the tetrahedral reaction intermediate. This compound inhibits the deamination of cytosine with a K{sub i} of 52 nM. The zinc- and iron-containing enzymes were characterized to determine the effect of the divalent cations on activation of the hydrolytic water. Fe-CDA loses activity at low pH with a kinetic pKa of 6.0, and Zn-CDA has a kinetic pKa of 7.3. Mutation of Gln-156 decreased the catalytic activity by more than 5 orders of magnitude, supporting its role in substrate binding. Mutation of Glu-217, Asp-313, and His-246 significantly decreased catalytic activity supporting the role of these three residues in activation of the hydrolytic water molecule and facilitation of proton transfer reactions. A library of potential substrates was used to probe the structural determinants responsible for catalytic activity. CDA was able to catalyze the deamination of isocytosine and the hydrolysis of 3-oxauracil. Large inverse solvent isotope effects were obtained on k{sub cat} and k{sub cat}/K{sub m}, consistent with the formation of a low-barrier hydrogen bond during the conversion of cytosine to uracil. A chemical mechanism for substrate deamination by CDA was proposed.

  11. Catalytic Conversion of Cellulose to Levulinic Acid by Metal Chlorides

    Directory of Open Access Journals (Sweden)

    Beixiao Zhang

    2010-08-01

    Full Text Available The catalytic performance of various metal chlorides in the conversion of cellulose to levulinic acid in liquid water at high temperatures was investigated. The effects of reaction parameters on the yield of levulinic acid were also explored. The results showed that alkali and alkaline earth metal chlorides were not effective in conversion of cellulose, while transition metal chlorides, especially CrCl3, FeCl3 and CuCl2 and a group IIIA metal chloride (AlCl3, exhibited high catalytic activity. The catalytic performance was correlated with the acidity of the reaction system due to the addition of the metal chlorides, but more dependent on the type of metal chloride. Among those metal chlorides, chromium chloride was found to be exceptionally effective for the conversion of cellulose to levulinic acid, affording an optimum yield of 67 mol % after a reaction time of 180 min, at 200 °C, with a catalyst dosage of 0.02 M and substrate concentration of 50 wt %. Chromium metal, most of which was present in its oxide form in the solid sample and only a small part in solution as Cr3+ ion, can be easily separated from the resulting product mixture and recycled. Finally, a plausible reaction scheme for the chromium chloride catalyzed conversion of cellulose in water was proposed.

  12. Catalytic hot gas cleaning of gasification gas

    Energy Technology Data Exchange (ETDEWEB)

    Simell, P. [VTT Energy, Espoo (Finland). Energy Production Technologies

    1997-12-31

    The aim of this work was to study the catalytic cleaning of gasification gas from tars and ammonia. In addition, factors influencing catalytic activity in industrial applications were studied, as well as the effects of different operation conditions and limits. Also the catalytic reactions of tar and ammonia with gasification gas components were studied. The activities of different catalyst materials were measured with laboratory-scale reactors fed by slip streams taken from updraft and fluid bed gasifiers. Carbonate rocks and nickel catalysts proved to be active tar decomposing catalysts. Ammonia decomposition was in turn facilitated by nickel catalysts and iron materials like iron sinter and iron dolomite. Temperatures over 850 deg C were required at 2000{sup -1} space velocity at ambient pressure to achieve almost complete conversions. During catalytic reactions H{sub 2} and CO were formed and H{sub 2}O was consumed in addition to decomposing hydrocarbons and ammonia. Equilibrium gas composition was almost achieved with nickel catalysts at 900 deg C. No deactivation by H{sub 2}S or carbon took place in these conditions. Catalyst blocking by particulates was avoided by using a monolith type of catalyst. The apparent first order kinetic parameters were determined for the most active materials. The activities of dolomite, nickel catalyst and reference materials were measured in different gas atmospheres using laboratory apparatus. This consisted of nitrogen carrier, toluene as tar model compound, ammonia and one of the components H{sub 2}, H{sub 2}O, CO, CO{sub 2}, CO{sub 2}+H{sub 2}O or CO+CO{sub 2}. Also synthetic gasification gas was used. With the dolomite and nickel catalyst the highest toluene decomposition rates were measured with CO{sub 2} and H{sub 2}O. In gasification gas, however, the rate was retarded due to inhibition by reaction products (CO, H{sub 2}, CO{sub 2}). Tar decomposition over dolomite was modelled by benzene reactions with CO{sub 2}, H

  13. Catalytic conversion of light alkanes

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, J.E.

    1992-06-30

    The second Quarterly Report of 1992 on the Catalytic Conversion of Light Alkanes reviews the work done between April 1, 1992 and June 31, 1992 on the Cooperative Agreement. The mission of this work is to devise a new catalyst which can be used in a simple economic process to convert the light alkanes in natural gas to oxygenate products that can either be used as clean-burning, high octane liquid fuels, as fuel components or as precursors to liquid hydrocarbon uwspomdon fuel. During the past quarter we have continued to design, prepare, characterize and test novel catalysts for the mild selective reaction of light hydrocarbons with air or oxygen to produce alcohols directly. These catalysts are designed to form active metal oxo (MO) species and to be uniquely active for the homolytic cleavage of the carbon-hydrogen bonds in light alkanes producing intermediates which can form alcohols. We continue to investigate three molecular environments for the active catalytic species that we are trying to generate: electron-deficient macrocycles (PHASE I), polyoxometallates (PHASE II), and regular oxidic lattices including zeolites and related structures as well as other molecular surface structures having metal oxo groups (PHASE I).

  14. Catalytic reforming feed characterisation technique

    Energy Technology Data Exchange (ETDEWEB)

    Larraz Mora, R.; Arvelo Alvarez, R. [Univ. of La Laguna, Chemical Engineering Dept., La Laguna (Spain)

    2002-09-01

    The catalytic reforming of naphtha is one of the major refinery processes, designed to increase the octane number of naphtha or to produce aromatics. The naphtha used as catalytic reformer feedstock usually contains a mixture of paraffins, naphthenes, and aromatics in the carbon number range C{sub 6} to C{sub 10}. The detailed chemical composition of the feed is necessary to predict the aromatics and hydrogen production as well as the operation severity. The analysis of feed naphtha is usually reported in terms of its ASTM distillation curve and API or specific gravity. Since reforming reactions are described in terms of lumped chemical species (paraffins, naphthenes and aromatics), a feed characterisation technique should be useful in order to predict reforming operating conditions and detect feed quality changes. Unfortunately online analyzer applications as cromatography or recently introduced naphtha NMR [1] are scarce in most of refineries. This work proposes an algorithmic characterisation method focusing on its main steps description. The method could help on the subjects previously described, finally a calculation example is shown. (orig.)

  15. Effect of plant cultivation,phosphorus fertilization and co-existing polycyclic aromatic hydrocarbons (PAHs) on biodegradation of PAHs%植物、施磷量及多环芳烃共存对多环芳烃生物降解影响

    Institute of Scientific and Technical Information of China (English)

    周笑白; 周集体; 项学敏

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants with toxic, mutagenic and carcingenic properties. Pot experiment and microplate experiments are conducted to investigate the impact of plant cultivation, phosphorus fertilization and PAHs co-existence on the removal rate of phenanthracene (PHE), pyrene (PYR) and dihenzo [a, hi anthracene (DBA). Results show that the dissipation and degraders of PHE are significantly higher than those of PYR and DBA in both pot and microplate experiments. In pot experiment, plants and higher quantity of phosphorus fertilizer increase DBA dissipation. Different interactions are obtained among the co- existing PAHs. The results show that co-existence of different PAH compounds can lead to synergistic co-metabolism (PHE enhanced DBA degradation), no co-metabolism (PYR and DBA) and inhibition of PAH degradation (PYR inhibited PHE+DBA degradation). The positive effect of PHE on DBA dissipation decreases with time course, which is probably due to the decrease of PHE concentration or the toxicity and accumulation of DBA degradation products in the substrate.%多环芳烃(PAHs)是具有“三致”效应的持久性有机污染物.通过盆栽及微生物培养实验,考察了植物、施磷量及PAHs共存对菲(PHE)、芘(PYR)和二苯并葸(DBA)去除率的影响,发现PHE的降解率和降解菌量均高于PYR和DBA.盆栽实验中,植物种植和给植物施加高磷浓度的营养液可促进DBA的降解;微生物培养实验表明共存的PAHs之间存在相互作用,而这种作用随PAHs种类不同可表现为促进降解作用(如PHE促进DBA降解)、无作用(如PYR和DBA)或抑制作用(如PYR抑制PHE+DBA降解).PHE对DBA降解的促进作用随时间的增加而减弱,这可能与PHE浓度降低和DBA中间产物的毒性及其积累有关.

  16. Catalytic strategy used by the myosin motor to hydrolyze ATP.

    Science.gov (United States)

    Kiani, Farooq Ahmad; Fischer, Stefan

    2014-07-22

    Myosin is a molecular motor responsible for biological motions such as muscle contraction and intracellular cargo transport, for which it hydrolyzes adenosine 5'-triphosphate (ATP). Early steps of the mechanism by which myosin catalyzes ATP hydrolysis have been investigated, but still missing are the structure of the final ADP·inorganic phosphate (Pi) product and the complete pathway leading to it. Here, a comprehensive description of the catalytic strategy of myosin is formulated, based on combined quantum-classical molecular mechanics calculations. A full exploration of catalytic pathways was performed and a final product structure was found that is consistent with all experiments. Molecular movies of the relevant pathways show the different reorganizations of the H-bond network that lead to the final product, whose γ-phosphate is not in the previously reported HPγO4(2-) state, but in the H2PγO4(-) state. The simulations reveal that the catalytic strategy of myosin employs a three-pronged tactic: (i) Stabilization of the γ-phosphate of ATP in a dissociated metaphosphate (PγO3(-)) state. (ii) Polarization of the attacking water molecule, to abstract a proton from that water. (iii) Formation of multiple proton wires in the active site, for efficient transfer of the abstracted proton to various product precursors. The specific role played in this strategy by each of the three loops enclosing ATP is identified unambiguously. It explains how the precise timing of the ATPase activation during the force generating cycle is achieved in myosin. The catalytic strategy described here for myosin is likely to be very similar in most nucleotide hydrolyzing enzymes.

  17. Electrochemical promotion of catalytic reactions

    Science.gov (United States)

    Imbihl, R.

    2010-05-01

    The electrochemical promotion of heterogeneously catalyzed reactions (EPOC) became feasible through the use of porous metal electrodes interfaced to a solid electrolyte. With the O 2- conducting yttrium stabilized zirconia (YSZ), the Na + conducting β″-Al 2O 3 (β-alumina), and several other types of solid electrolytes the EPOC effect has been demonstrated for about 100 reaction systems in studies conducted mainly in the mbar range. Surface science investigations showed that the physical basis for the EPOC effect lies in the electrochemically induced spillover of oxygen and alkali metal, respectively, onto the surface of the metal electrodes. For the catalytic promotion effect general concepts and mechanistic schemes were proposed but these concepts and schemes are largely speculative. Applying surface analytical tools to EPOC systems the proposed mechanistic schemes can be verified or invalidated. This report summarizes the progress which has been achieved in the mechanistic understanding of the EPOC effect.

  18. Catalytic Graphitization of Phenolic Resin

    Institute of Scientific and Technical Information of China (English)

    Mu Zhao; Huaihe Song

    2011-01-01

    The catalytic graphitization of thermal plastic phenolic-formaldehyde resin with the aid of ferric nitrate (FN) was studied in detail. The morphologies and structural features of the products including onion-like carbon nanoparticles and bamboo-shaped carbon nanotubes were investigated by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction and Raman spectroscopy measurements. It was found that with the changes of loading content of FN and residence time at 1000℃, the products exhibited various morphologies. The TEM images showed that bamboo-shaped carbon nanotube consisted of tens of bamboo sticks and onion-like carbon nanoparticle was made up of quasi-spherically concentrically closed carbon nanocages.

  19. Unsteady processes in catalytic reactors

    Energy Technology Data Exchange (ETDEWEB)

    Matros, Yu.Sh.

    1985-01-01

    In recent years a realization has occurred that reaction and reactor dynamics must be considered when designing and operating catalytic reactors. In this book, the author has focussed on both the processes occurring on individual porous-catalyst particles as well as the phenomena displayed by collections of these particles in fixed-bed reactors. The major topics discussed include the effects of unsteady-state heat and mass transfer, the influence of inhomogeneities and stagnant regions in fixed beds, and reactor operation during forced cycling of operating conditions. Despite the title of the book, attention is also paid to the determination of the number and stability of fixed-bed steady states, with the aim of describing the possibility of controlling reactors at unstable steady states. However, this development is somewhat dated, given the recent literature on multiplicity phenomena and process control.

  20. Non-catalytic recuperative reformer

    Energy Technology Data Exchange (ETDEWEB)

    Khinkis, Mark J.; Kozlov, Aleksandr P.; Kurek, Harry

    2015-12-22

    A non-catalytic recuperative reformer has a flue gas flow path for conducting hot flue gas from a thermal process and a reforming mixture flow path for conducting a reforming mixture. At least a portion of the reforming mixture flow path is embedded in the flue gas flow path to permit heat transfer from the hot flue gas to the reforming mixture. The reforming mixture flow path contains substantially no material commonly used as a catalyst for reforming hydrocarbon fuel (e.g., nickel oxide, platinum group elements or rhenium), but instead the reforming mixture is reformed into a higher calorific fuel via reactions due to the heat transfer and residence time. In a preferred embodiment, extended surfaces of metal material such as stainless steel or metal alloy that are high in nickel content are included within at least a portion of the reforming mixture flow path.

  1. Selective catalytic oxidation of ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J.; Koljonen, T. [VTT Energy, Espoo (Finland)

    1996-12-31

    In the combustion of fossil fuels, the principal source of nitrogen oxides is nitrogen bound in the fuel structure. In gasification, a large part of fuel nitrogen forms NH{sub 3}, which may form nitrogen oxides during gas combustion. If NH{sub 3} and other nitrogen species could be removed from hot gas, the NO emission could be considerably reduced. However, relatively little attention has been paid to finding new means of removing nitrogen compounds from the hot gasification gas. The possibility of selectively oxidizing NH{sub 3} to N{sub 2} in the hot gasification has been studied at VTT Energy. The largest NH{sub 3} reductions have been achieved by catalytic oxidation on aluminium oxides. (author) (4 refs.)

  2. Method of fabricating a catalytic structure

    Science.gov (United States)

    Rollins, Harry W.; Petkovic, Lucia M.; Ginosar, Daniel M.

    2009-09-22

    A precursor to a catalytic structure comprising zinc oxide and copper oxide. The zinc oxide has a sheet-like morphology or a spherical morphology and the copper oxide comprises particles of copper oxide. The copper oxide is reduced to copper, producing the catalytic structure. The catalytic structure is fabricated by a hydrothermal process. A reaction mixture comprising a zinc salt, a copper salt, a hydroxyl ion source, and a structure-directing agent is formed. The reaction mixture is heated under confined volume conditions to produce the precursor. The copper oxide in the precursor is reduced to copper. A method of hydrogenating a carbon oxide using the catalytic structure is also disclosed, as is a system that includes the catalytic structure.

  3. Influence of Co-existing Species on Charge Transfer in Dye-sensitized TiO2 Nanocrystalline System%共存牺牲剂对染料敏化TiO2纳米晶体系电子传输的影响

    Institute of Scientific and Technical Information of China (English)

    成荣敏; 李娜; 詹从红

    2014-01-01

    Dye-sensitized nanocrystalline TiO2 colloidal suspensions in aqueous system were applied for H2 evolution under visible light(>390 nm) . In these suspension systems, the efficiency of H2 evolution is strongly influenced by the dye-sensitizers, a ruthenium complex, (n-Bu4N)2-cis-[Ru(dcbpy)(SCN)2](N719, dcb-py=4,4’-dicarboxy-2,2’-bipyridine) and porphyrin derivatives 5,10,15,20-tetra(4-carboxyphenyl) porphyrin ( TCPP) and tetra-( p-sulfonato phenyl) porphyrin( TPPS) , and the combination with co-existing electron do-nor species, methanol ( MeOH ) and triethanolamine ( TEOA ) . The analysis of fluorescence quenching and photoelectrochemical studies reveal that the charge transfer between the excited dye-sensitizers and TiO2 is strongly influenced by the surroundings, especially the concentration of co-existing donor species rather than the pH values of the surrounding solution. It is benefit for achieving higher conversion efficiency for not only the photocatalysts but also the photovoltaics using dye-sensitized of TiO2 nanoparticles.%采用卟啉染料敏化TiO2纳米晶在可见光条件下(λ>390 nm)进行水分解制氢。考察了不同牺牲剂---甲醇( MeOH)、三乙醇胺( TEOA)及其混合物对体系析氢效率的影响。通过荧光猝灭及光电化学性能分析发现,激发态染料与TiO2之间的电子转移极大地受到添加的牺牲剂的影响,而体系的pH值对其影响不大。

  4. Catalytic pyrolysis using UZM-39 aluminosilicate zeolite

    Science.gov (United States)

    Nicholas, Christpher P; Boldingh, Edwin P

    2013-12-17

    A new family of coherently grown composites of TUN and IMF zeotypes has been synthesized and show to be effective catalysts for catalytic pyrolysis of biomass. These zeolites are represented by the empirical formula. Na.sub.nM.sub.m.sup.n+R.sub.rQ.sub.qAl.sub1-xE.sub.xSi.sub.yO.s- ub.z where M represents zinc or a metal or metals from Group 1, Group 2, Group 3 or the lanthanide series of the periodic table, R is an A,.OMEGA.-dihalosubstituted paraffin such as 1,4-dibromobutane, Q is a neutral amine containing 5 or fewer carbon atoms such as 1-methylpyrrolidine and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-39 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hyrdocarbons into hydrocarbons removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

  5. Catalytic pyrolysis using UZM-39 aluminosilicate zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas, Christopher P; Boldingh, Edwin P

    2014-10-07

    A new family of coherently grown composites of TUN and IMF zeotypes has been synthesized and shown to be effective catalysts for catalytic pyrolysis of biomass. These zeolites are represented by the empirical formula. Na.sub.nM.sub.m.sup.n+R.sub.rQ.sub.qAl.sub.1-xE.sub.xSi.sub.yO.s- ub.z where M represents zinc or a metal or metals from Group 1, Group 2, Group 3 or the lanthanide series of the periodic table, R is an A,.OMEGA.-dihalosubstituted paraffin such as 1,4-dibromobutane, Q is a neutral amine containing 5 or fewer carbon atoms such as 1-methylpyrrolidine and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-39 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hydrocarbons into hydrocarbons and removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

  6. Catalytic glycerol steam reforming for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Dan, Monica, E-mail: monica.dan@itim-cj.ro; Mihet, Maria, E-mail: maria.mihet@itim-cj.ro; Lazar, Mihaela D., E-mail: diana.lazar@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj Napoca (Romania)

    2015-12-23

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H{sub 2}. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al{sub 2}O{sub 3}. The catalyst was prepared by wet impregnation method and characterized through different methods: N{sub 2} adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H{sub 2}, CH{sub 4}, CO, CO{sub 2}. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H{sub 2}O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.

  7. Catalytic glycerol steam reforming for hydrogen production

    Science.gov (United States)

    Dan, Monica; Mihet, Maria; Lazar, Mihaela D.

    2015-12-01

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H2. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al2O3. The catalyst was prepared by wet impregnation method and characterized through different methods: N2 adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H2, CH4, CO, CO2. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H2O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.

  8. Revolutionary systems for catalytic combustion and diesel catalytic particulate traps.

    Energy Technology Data Exchange (ETDEWEB)

    Stuecker, John Nicholas; Witze, Peter O.; Ferrizz, Robert Matthew; Cesarano, Joseph, III; Miller, James Edward

    2004-12-01

    This report is a summary of an LDRD project completed for the development of materials and structures conducive to advancing the state of the art for catalyst supports and diesel particulate traps. An ancillary development for bio-medical bone scaffolding was also realized. Traditionally, a low-pressure drop catalyst support, such as a ceramic honeycomb monolith, is used for catalytic reactions that require high flow rates of gases at high-temperatures. A drawback to the traditional honeycomb monoliths under these operating conditions is poor mass transfer to the catalyst surface in the straight-through channels. ''Robocasting'' is a unique process developed at Sandia National Laboratories that can be used to manufacture ceramic monoliths with alternative 3-dimensional geometries, providing tortuous pathways to increase mass transfer while maintaining low-pressure drops. These alternative 3-dimensional geometries may also provide a foundation for the development of self-regenerating supports capable of trapping and combusting soot particles from a diesel engine exhaust stream. This report describes the structures developed and characterizes the improved catalytic performance that can result. The results show that, relative to honeycomb monolith supports, considerable improvement in mass transfer efficiency is observed for robocast samples synthesized using an FCC-like geometry of alternating rods. Also, there is clearly a trade-off between enhanced mass transfer and increased pressure drop, which can be optimized depending on the particular demands of a given application. Practical applications include the combustion of natural gas for power generation, production of syngas, and hydrogen reforming reactions. The robocast lattice structures also show practicality for diesel particulate trapping. Preliminary results for trapping efficiency are reported as well as the development of electrically resistive lattices that can regenerate the structure

  9. Water Purification

    Science.gov (United States)

    1994-01-01

    The Vision Catalyst Purifier employs the basic technology developed by NASA to purify water aboard the Apollo spacecraft. However, it also uses an "erosion" technique. The purifier kills bacteria, viruses, and algae by "catalytic corrosion." A cartridge contains a silver-impregnated alumina bed with a large surface area. The catalyst bed converts oxygen in a pool of water to its most oxidative state, killing over 99 percent of the bacteria within five seconds. The cartridge also releases into the pool low levels of ionic silver and copper through a controlled process of erosion. Because the water becomes electrochemically active, no electricity is required.

  10. Model catalytic oxidation studies using supported monometallic and heterobimetallic oxides

    Energy Technology Data Exchange (ETDEWEB)

    Ekerdt, J.G.

    1992-02-03

    This research program is directed toward a more fundamental understanding of the effects of catalyst composition and structure on the catalytic properties of metal oxides. Metal oxide catalysts play an important role in many reactions bearing on the chemical aspects of energy processes. Metal oxides are the catalysts for water-gas shift reactions, methanol and higher alcohol synthesis, isosynthesis, selective catalytic reduction of nitric oxides, and oxidation of hydrocarbons. A key limitation to developing insight into how oxides function in catalytic reactions is in not having precise information of the surface composition under reaction conditions. To address this problem we have prepared oxide systems that can be used to study cation-cation effects and the role of bridging (-O-) and/or terminal (=O) surface oxygen anion ligands in a systematic fashion. Since many oxide catalyst systems involve mixtures of oxides, we selected a model system that would permit us to examine the role of each cation separately and in pairwise combinations. Organometallic molybdenum and tungsten complexes were proposed for use, to prepare model systems consisting of isolated monomeric cations, isolated monometallic dimers and isolated bimetallic dimers supported on silica and alumina. The monometallic and bimetallic dimers were to be used as models of more complex mixed- oxide catalysts. Our current program was to develop the systems and use them in model oxidation reactions.

  11. Topological entropy of catalytic sets: Hypercycles revisited

    Science.gov (United States)

    Sardanyés, Josep; Duarte, Jorge; Januário, Cristina; Martins, Nuno

    2012-02-01

    The dynamics of catalytic networks have been widely studied over the last decades because of their implications in several fields like prebiotic evolution, virology, neural networks, immunology or ecology. One of the most studied mathematical bodies for catalytic networks was initially formulated in the context of prebiotic evolution, by means of the hypercycle theory. The hypercycle is a set of self-replicating species able to catalyze other replicator species within a cyclic architecture. Hypercyclic organization might arise from a quasispecies as a way to increase the informational containt surpassing the so-called error threshold. The catalytic coupling between replicators makes all the species to behave like a single and coherent evolutionary multimolecular unit. The inherent nonlinearities of catalytic interactions are responsible for the emergence of several types of dynamics, among them, chaos. In this article we begin with a brief review of the hypercycle theory focusing on its evolutionary implications as well as on different dynamics associated to different types of small catalytic networks. Then we study the properties of chaotic hypercycles with error-prone replication with symbolic dynamics theory, characterizing, by means of the theory of topological Markov chains, the topological entropy and the periods of the orbits of unimodal-like iterated maps obtained from the strange attractor. We will focus our study on some key parameters responsible for the structure of the catalytic network: mutation rates, autocatalytic and cross-catalytic interactions.

  12. Catalytic partial oxidation of pyrolysis oils

    Science.gov (United States)

    Rennard, David Carl

    2009-12-01

    details the catalytic partial oxidation of glycerol without preheat: droplets of glycerol are sprayed directly onto the top of the catalyst bed, where they react autothermally with contact times on the order of tau ≈ 30 ms. The reactive flash volatilization of glycerol results in equilibrium syngas production over Rh-Ce catalysts. In addition, water can be added to the liquid glycerol, resulting in true autothermal reforming. This highly efficient process can increase H2 yields and alter the H2 to CO ratio, allowing for flexibility in syngas quality depending on the purpose. Chapter 5 details the results of a time on stream experiment, in which optimal syngas conditions are chosen. Although conversion is 100% for 450 hours, these experiments demonstrate the deactivation of the catalyst over time. Deactivation is exhibited by decreases in H2 and CO 2 production accompanied by a steady increase in CO and temperature. These results are explained as a loss of water-gas shift equilibration. SEM images suggest catalyst sintering may play a role; EDS indicates the presence of impurities on the catalyst. In addition, the instability of quartz in the reactor is demonstrated by etching, resulting in a hole in the reactor tube at the end of the experiment. These results suggest prevaporization may be desirable in this application, and that quartz is not a suitable material for the reactive flash volatilization of oxygenated fuels. In Chapter 6, pyrolysis oil samples from three sources - poplar, pine, and hardwoods - are explored in the context of catalytic partial oxidation. Lessons derived from the tests with model compounds are applied to reactor design, resulting in the reactive flash vaporization of bio oils. Syngas is successfully produced, though deactivation due to coke and ash deposition keeps H2 below equlibrium. Coke formation is observed on the reactor walls, but is avoided between the fuel injection site and catalyst by increasing the proximity of these in the reactor

  13. Development of Catalytic Cooking Plates

    Energy Technology Data Exchange (ETDEWEB)

    Hjelm, Anna-Karin; Silversand, Fredrik [CATATOR AB, Lund (Sweden); Tena, Emmanuel; Berger, Marc [Gaz de France (France)

    2004-04-01

    Gas catalytic combustion for gas stoves or cooking plates (closed catalytic burner system with ceramic plates) is a very promising technique in terms of ease of cleaning, power modulation and emissions. Previous investigations show that wire mesh catalysts, prepared and supplied by Catator AB (CAT), seem to be very well suited for such applications. Beside significantly reducing the NOx-emissions, these catalysts offer important advantages such as good design flexibility, low pressure drop and high heat transfer capacity, where the latter leads to a quick thermal response. Prior to this project, Gaz de France (GdF) made a series of measurements with CAT's wire mesh catalysts in their gas cooking plates and compared the measured performance with similar results obtained with theirs cordierite monolith catalysts. Compared to the monolith catalyst, the wire mesh catalyst was found to enable very promising results with respect to both emission levels (<10 mg NO{sub x} /kWh, <5 mg CO/kWh) and life-time (>8000 h vs. 700 h at 200 kW/m{sup 2}). It was however established that the radiation and hence, the thermal efficiency of the cooking plate, was significantly less than is usually measured in combination with the monolith (15 % vs. 32 %). It was believed that the latter could be improved by developing new burner designs based on CAT's wire mesh concept. As a consequence, a collaboration project between GdF, CAT and the Swedish Gas Technology AB was created. This study reports on the design, the construction and the evaluation of new catalytic burners, based on CAT's wire mesh catalysts, used for the combustion of natural gas in gas cooking stoves. The evaluation of the burners was performed with respect to key factors such as thermal efficiency, emission quality and pressure drop, etc, by the use of theoretical simulations and experimental tests. Impacts of parameters such as the the wire mesh number, the wire mesh structure (planar or folded), the

  14. Insights into the mechanism of the reaction between tetrachloro-p-benzoquinone and hydrogen peroxide and their implications in the catalytic role of water molecules in producing the hydroxyl radial.

    Science.gov (United States)

    Li, Ping; Wang, Weihua; Sun, Qiao; Li, Zhen; Du, Aijun; Bi, Siwei; Zhao, Yan

    2013-08-26

    Detailed mechanisms for the formation of hydroxyl or alkoxyl radicals in the reactions between tetrachloro-p-benzoquinone (TCBQ) and organic hydroperoxides are crucial for better understanding the potential carcinogenicity of polyhalogenated quinones. Herein, the mechanism of the reaction between TCBQ and H2O2 has been systematically investigated at the B3LYP/6-311++G** level of theory in the presence of different numbers of water molecules. We report that the whole reaction can easily take place with the assistance of explicit water molecules. Namely, an initial intermediate is formed first. After that, a nucleophilic attack of H2O2 onto TCBQ occurs, which results in the formation of a second intermediate that contains an OOH group. Subsequently, this second intermediate decomposes homolytically through cleavage of the O-O bond to produce a hydroxyl radical. Energy analyses suggest that the nucleophilic attack is the rate-determining step in the whole reaction. The participation of explicit water molecules promotes the reaction significantly, which can be used to explain the experimental phenomena. In addition, the effects of F, Br, and CH3 substituents on this reaction have also been studied.

  15. Catalytic Wittig and aza-Wittig reactions

    Directory of Open Access Journals (Sweden)

    Zhiqi Lao

    2016-11-01

    Full Text Available This review surveys the literature regarding the development of catalytic versions of the Wittig and aza-Wittig reactions. The first section summarizes how arsenic and tellurium-based catalytic Wittig-type reaction systems were developed first due to the relatively easy reduction of the oxides involved. This is followed by a presentation of the current state of the art regarding phosphine-catalyzed Wittig reactions. The second section covers the field of related catalytic aza-Wittig reactions that are catalyzed by both phosphine oxides and phosphines.

  16. Halogen Chemistry on Catalytic Surfaces.

    Science.gov (United States)

    Moser, Maximilian; Pérez-Ramírez, Javier

    2016-01-01

    Halogens are key building blocks for the manufacture of high-value products such as chemicals, plastics, and pharmaceuticals. The catalytic oxidation of HCl and HBr is an attractive route to recover chlorine and bromine in order to ensure the sustainability of the production processes. Very few materials withstand the high corrosiveness and the strong exothermicity of the reactions and among them RuO2 and CeO2-based catalysts have been successfully applied in HCl oxidation. The search for efficient systems for HBr oxidation was initiated by extrapolating the results of HCl oxidation based on the chemical similarity of these reactions. Interestingly, despite its inactivity in HCl oxidation, TiO2 was found to be an outstanding HBr oxidation catalyst, which highlighted that the latter reaction is more complex than previously assumed. Herein, we discuss the results of recent comparative studies of HCl and HBr oxidation on both rutile-type (RuO2, IrO2, and TiO2) and ceria-based catalysts using a combination of advanced experimental and theoretical methods to provide deeper molecular-level understanding of the reactions. This knowledge aids the design of the next-generation catalysts for halogen recycling.

  17. Catalytic Chemistry on Oxide Nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Asthagiri, Aravind; Dixon, David A.; Dohnalek, Zdenek; Kay, Bruce D.; Rodriquez, Jose A.; Rousseau, Roger J.; Stacchiola, Dario; Weaver, Jason F.

    2016-05-29

    Metal oxides represent one of the most important and widely employed materials in catalysis. Extreme variability of their chemistry provides a unique opportunity to tune their properties and to utilize them for the design of highly active and selective catalysts. For bulk oxides, this can be achieved by varying their stoichiometry, phase, exposed surface facets, defect, dopant densities and numerous other ways. Further, distinct properties from those of bulk oxides can be attained by restricting the oxide dimensionality and preparing them in the form of ultrathin films and nanoclusters as discussed throughout this book. In this chapter we focus on demonstrating such unique catalytic properties brought by the oxide nanoscaling. In the highlighted studies planar models are carefully designed to achieve minimal dispersion of structural motifs and to attain detailed mechanistic understanding of targeted chemical transformations. Detailed level of morphological and structural characterization necessary to achieve this goal is accomplished by employing both high-resolution imaging via scanning probe methods and ensemble-averaged surface sensitive spectroscopic methods. Three prototypical examples illustrating different properties of nanoscaled oxides in different classes of reactions are selected.

  18. The Influence of Co existing Ions on Adsorping Cadmium in Water by Water-washing Waste Saccharomyces Cerevisiae%共存离子对水洗废啤酒酵母吸附水相中Cd2+的影响

    Institute of Scientific and Technical Information of China (English)

    代淑娟; 高太; 王玉娟; 刘文刚

    2008-01-01

    以水洗废啤酒酵母为吸附剂,以废水中镉离子对吸附对象,考察了重金属铜铅锌离子、碱土金属阳离子及一些负离子对吸附效果的影响.结果表明,重金属铜、铅、锌离子对吸附效果影响显著,而碱土金属离子及负离子对吸附效果影响相对较小.

  19. Microorganism controlling of the circulating water system in catalytic cracking unit%催化裂化装置循环水系统的微生物控制

    Institute of Scientific and Technical Information of China (English)

    任世科; 骆重阳; 高磊

    2011-01-01

    石化工业循环水系统中油料泄漏是一个普遍存在的问题,针对炼油厂油料泄漏对催化裂化装置循环水系统所造成的危害,研制出一套综合的微生物控制技术,并制定出了相应的工艺实施方法,抑制了微生物的繁殖和黏泥的滋生,很好地控制了系统的腐蚀与结垢,使循环水系统在发生油料泄漏后能迅速由恶性运行状态转化为良性循环运行状态.%Oil leakage in circulatling water systems is a common problem in petrochemical industry,which has caused great expense. It indicates that the integrated microorganism controlling has excellent anti-microorganism and antislime characteristics. This technology also has excellent efficiency in controlling corrosion and scale. The microorganism controlling method is economically easy to be operated and can meet the requirements of circulating water quality improvement.

  20. Catalytic flash pyrolysis of oil-impregnated-wood and jatropha cake using sodium based catalysts

    KAUST Repository

    Imran, Ali

    2015-11-24

    Catalytic pyrolysis of wood with impregnated vegetable oil was investigated and compared with catalytic pyrolysis of jatropha cake making use of sodium based catalysts to produce a high quality bio-oil. The catalytic pyrolysis was carried out in two modes: in-situ catalytic pyrolysis and post treatment of the pyrolysis vapors. The in-situ catalytic pyrolysis was carried out in an entrained flow reactor system using a premixed feedstock of Na2CO3 and biomass and post treatment of biomass pyrolysis vapor was conducted in a downstream fixed bed reactor of Na2CO3/γ-Al2O3. Results have shown that both Na2CO3 and Na2CO3/γ-Al2O3 can be used for the production of a high quality bio-oil from catalytic pyrolysis of oil-impregnated-wood and jatropha cake. The catalytic bio-oil had very low oxygen content, water content as low as 1wt.%, a neutral pH, and a high calorific value upto 41.8MJ/kg. The bio-oil consisted of high value chemical compounds mainly hydrocarbons and undesired compounds in the bio-oil were either completely removed or considerably reduced. Increasing the triglycerides content (vegetable oil) in the wood enhanced the formation of hydrocarbons in the bio-oil. Post treatment of the pyrolysis vapor over a fixed bed of Na2CO3/γ-Al2O3 produced superior quality bio-oil compared to in-situ catalytic pyrolysis with Na2CO3. This high quality bio-oil may be used as a precursor in a fractionating process for the production of alternative fuels. © 2015 Elsevier B.V.

  1. Catalytic models developed through social work

    DEFF Research Database (Denmark)

    Jensen, Mogens

    2015-01-01

    The article develops the concept of catalytic processes in relation to social work with adolescents in an attempt to both reach a more nuanced understanding of social work and at the same time to develop the concept of catalytic processes in psychology. The social work is pedagogical treatment...... of adolescents placed in out-of-home care and is characterised using three situated cases as empirical data. Afterwards the concept of catalytic processes is briefly presented and then applied in an analysis of pedagogical treatment in the three cases. The result is a different conceptualisation of the social...... work with new possibilities of development of the work, but also suggestions for development of the concept of catalytic processes....

  2. Catalytic converters as a source of platinum

    Directory of Open Access Journals (Sweden)

    A. Fornalczyk

    2011-10-01

    Full Text Available The increase of Platinum Group Metals demand in automotive industry is connected with growing amount of cars equipped with the catalytic converters. The paper presents the review of available technologies during recycling process. The possibility of removing platinum from the used catalytic converters applying pyrometallurgical and hyrdometallurgical methods were also investigated. Metals such as Cu, Pb, Ca, Mg, Cd were used in the pyrometallurgical research (catalytic converter was melted with Cu, Pb and Ca or Mg and Cd vapours were blown through the whole carrier. In hydrometallurgical research catalytic converters was dissolved in aqua regia. Analysis of Pt contents in the carrier before and after the process was performed by means of atomic absorption spectroscopy. Obtained result were discussed.

  3. Catalytic Asymmetric Synthesis of Phosphine Boronates

    NARCIS (Netherlands)

    Hornillos, Valentin; Vila, Carlos; Otten, Edwin; Feringa, Ben L.

    2015-01-01

    The first catalytic enantioselective synthesis of ambiphilic phosphine boronate esters is presented. The asymmetric boration of ,-unsaturated phosphine oxides catalyzed by a copper bisphosphine complex affords optically active organoboronate esters that bear a vicinal phosphine oxide group in good y

  4. Catalytic Radical Domino Reactions in Organic Synthesis

    Science.gov (United States)

    Sebren, Leanne J.; Devery, James J.; Stephenson, Corey R.J.

    2014-01-01

    Catalytic radical-based domino reactions represent important advances in synthetic organic chemistry. Their development benefits synthesis by providing atom- and step-economical methods to complex molecules. Intricate combinations of radical, cationic, anionic, oxidative/reductive, and transition metal mechanistic steps result in cyclizations, additions, fragmentations, ring-expansions, and rearrangements. This Perspective summarizes recent developments in the field of catalytic domino processes. PMID:24587964

  5. MOBILE COMPLEX FOR CATALYTIC THERMAL WASTE TREATMENT

    Directory of Open Access Journals (Sweden)

    Vedi V.E.

    2012-12-01

    Full Text Available The design and purpose of the basic units of the mobile waste processing complex “MPK” are described. Experimental data of catalytic purification of exhaust gases are presented. Experimental data on catalytic clearing of final gases of a designed mobile incinerator plant are shown. It is defined, that concentrating of parasitic bridging in waste gases of the complex are considerably smaller, rather than allowed by normative documents.

  6. Temperature Modulation of a Catalytic Gas Sensor

    OpenAIRE

    Eike Brauns; Eva Morsbach; Sebastian Kunz; Marcus Baeumer; Walter Lang

    2014-01-01

    The use of catalytic gas sensors usually offers low selectivity, only based on their different sensitivities for various gases due to their different heats of reaction. Furthermore, the identification of the gas present is not possible, which leads to possible misinterpretation of the sensor signals. The use of micro-machined catalytic gas sensors offers great advantages regarding the response time, which allows advanced analysis of the sensor response. By using temperature modulation, additi...

  7. 再制造的行为模式:不完全竞争性与协同共生——基于产业组织理论视角的分析%Behavior Pattern of "Re-manufacturing": Imperfect Competition and Synergistic Co-existence --Analysis from the Perspective of Industrial Organization Theory

    Institute of Scientific and Technical Information of China (English)

    朱锐; 吴金明

    2012-01-01

    In accordance with the theory of industrial organization, re-manufacturing possess corporate behavior and market structure which under the conditions of imperfect competition, and have formed a unique pattern of behavior. This behavior pattern embodied in two aspects: imperfect competition and synergic co-existence. The nature of imperfect competition includes the targeting and oligopoly on used parts and remanufactured product's market, the entry barriers of technology and manufacturing modes, and government regulations on organization and business, etc. The collaborative co-existence comprises symbiosis of goals, collaboration of the business model, as well as vertical integration and vertical restraints based on the industry chain, etc. The two components of behavior model in manufacturing industry, exactly, leading to the shift down of manufacturing long-term cost curve, the finite change of optimal scale, and equally the e.nhancing of industrial concentration and monopoly. Moreover, this pattern has a profound impact on industry's market structure, efficiency and government policy.%按照产业组织理论,再制造具有不完全竞争条件下的企业行为与市场结构,并形成了独特的行为模式.这一行为模式集中体现在不完全竞争性与协同共生性两个方面:不完全竞争性包括对旧件和再制造产品市场的锁定与寡占、技术与制造模式的进入壁垒、组织与经营上的政府规制等方面,协同共生性包括目标上的共生、商业模式上的协同、基于产业链的垂直一体化和垂直约束等方面。正是再制造产业这种不完全竞争性与协同共生性.导致制造业长期成本曲线下移、最佳规模有限变动和产业集中度与垄断程度提升.并深刻影响制造业的市场结构、效率与政府政策。

  8. Determination of Trace Mercury by Catalytic Solid Substrate-room Temperature Phosphorimetry

    Institute of Scientific and Technical Information of China (English)

    Jia Ming LIU; Yun Xiong WU; Shao Xian LIN; Fei Ming LI; Xiu Mei SHI; Zhong Bin SHI; Guo Hui ZHU; Zhi Ming LI; Xiao Mei HUANG

    2006-01-01

    A new highly sensitive method (detection limit: 4.1 ag spot-1, sample volume: 0.4 μL spot-1) for the determination of trace Hg2+ by catalytic solid substrate-room temperature phosphorimetry has been established in this paper. This method has been successfully applied to determine trace Hg2+ in water.

  9. Adsorbent catalytic nanoparticles and methods of using the same

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. The Catalytic Reductive Dechlorination of Ni/Fe Nano-alloy to Trichloro Ethylene(TCE)in Water%纳米Ni/Fe合金对水中三氯乙烯(TCE)的催化还原脱氯

    Institute of Scientific and Technical Information of China (English)

    张卫华; 张春华; 陈保国

    2016-01-01

    利用纳米Ni/Fe合金粉末对水中TCE进行催化还原脱氯研究,结果表明,纳米Ni/Fe合金对水中TCE具有较好的脱氯作用.在Ni含量5wt%、初始pH值为6.5、Ni/Fe粉末投加量为0.4g/L的条件下,TCE的脱氯率在60min内达72%;合金中较高Ni含量、较低初始pH、较大的粉末投加量均有利于脱氯反应;脱氯产物为丁烷、丁烯和乙烷等,可推测该反应是发生在双金属合金表面的加氢脱氯.%Dechlorination rate of TCE is up to 72%within 60 minutes under conditions of 5 wt%Ni,initial pH value 6.5 and 0.4g/L Ni/Fe powder. With the higher Ni content,the lower initial pH value and the more Ni/Fe powder,the Ni/Fe nano-alloy powder can better dechlorinate TCE in the water and produce butane,butene and ethane. This hy-drodechlorination occurrs on the surface of Ni/Fe alloy.

  11. SOFC system with integrated catalytic fuel processing

    Science.gov (United States)

    Finnerty, Caine; Tompsett, Geoff. A.; Kendall, Kevin; Ormerod, R. Mark

    In recent years, there has been much interest in the development of solid oxide fuel cell technology operating directly on hydrocarbon fuels. The development of a catalytic fuel processing system, which is integrated with the solid oxide fuel cell (SOFC) power source is outlined here. The catalytic device utilises a novel three-way catalytic system consisting of an in situ pre-reformer catalyst, the fuel cell anode catalyst and a platinum-based combustion catalyst. The three individual catalytic stages have been tested in a model catalytic microreactor. Both temperature-programmed and isothermal reaction techniques have been applied. Results from these experiments were used to design the demonstration SOFC unit. The apparatus used for catalytic characterisation can also perform in situ electrochemical measurements as described in previous papers [C.M. Finnerty, R.H. Cunningham, K. Kendall, R.M. Ormerod, Chem. Commun. (1998) 915-916; C.M. Finnerty, N.J. Coe, R.H. Cunningham, R.M. Ormerod, Catal. Today 46 (1998) 137-145]. This enabled the performance of the SOFC to be determined at a range of temperatures and reaction conditions, with current output of 290 mA cm -2 at 0.5 V, being recorded. Methane and butane have been evaluated as fuels. Thus, optimisation of the in situ partial oxidation pre-reforming catalyst was essential, with catalysts producing high H 2/CO ratios at reaction temperatures between 873 K and 1173 K being chosen. These included Ru and Ni/Mo-based catalysts. Hydrocarbon fuels were directly injected into the catalytic SOFC system. Microreactor measurements revealed the reaction mechanisms as the fuel was transported through the three-catalyst device. The demonstration system showed that the fuel processing could be successfully integrated with the SOFC stack.

  12. SOFC system with integrated catalytic fuel processing

    Energy Technology Data Exchange (ETDEWEB)

    Finnerty, C.; Tompsett, G.A.; Kendall, K.; Ormerod, R.M. [Birchall Centre for Inorganic Chemistry and Materials Science, Keele Univ. (United Kingdom)

    2000-03-01

    In recent years, there has been much interest in the development of solid oxide fuel cell technology operating directly on hydrocarbon fuels. The development of a catalytic fuel processing system, which is integrated with the solid oxide fuel cell (SOFC) power source is outlined here. The catalytic device utilises a novel three-way catalytic system consisting of an in situ pre-reformer catalyst, the fuel cell anode catalyst and a platinum-based combustion catalyst. The three individual catalytic stages have been tested in a model catalytic microreactor. Both temperature-programmed and isothermal reaction techniques have been applied. Results from these experiments were used to design the demonstration SOFC unit. The apparatus used for catalytic characterisation can also perform in situ electrochemical measurements as described in previous papers [C.M. Finnerty, R.H. Cunningham, K. Kendall, R.M. Ormerod, Chem. Commun. (1998) 915-916; C.M. Finnerty, N.J. Coe, R.H. Cunningham, R.M. Ormerod, Catal. Today 46 (1998) 137-145]. This enabled the performance of the SOFC to be determined at a range of temperatures and reaction conditions, with current output of 290 mA cm{sup -2} at 0.5 V, being recorded. Methane and butane have been evaluated as fuels. Thus, optimisation of the in situ partial oxidation pre-reforming catalyst was essential, with catalysts producing high H{sub 2}/CO ratios at reaction temperatures between 873 K and 1173 K being chosen. These included Ru and Ni/Mo-based catalysts. Hydrocarbon fuels were directly injected into the catalytic SOFC system. Microreactor measurements revealed the reaction mechanisms as the fuel was transported through the three-catalyst device. The demonstration system showed that the fuel processing could be successfully integrated with the SOFC stack. (orig.)

  13. Catalytic coal liquefaction. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Weller, S W

    1981-01-01

    Monolith catalysts of MoO/sub 3/-CoO-Al/sub 2/O/sub 3/ were prepared and tested for coal liquefaction in a stirred autoclave. In general, the monolith catalysts were not as good as particulate catalysts prepared on Corning alumina supports. Measurement of O/sub 2/ chemisorption and BET surface area has been made on a series of Co/Mo/Al/sub 2/O/sub 3/ catalysts obtained from PETC. The catalysts were derived from Cyanamid 1442A and had been tested for coal liquefaction in batch autoclaves and continuous flow units. MoO/sub 3/-Al/sub 2/O/sub 3/ catalysts over the loading range 3.9 to 14.9 wt % MoO/sub 3/ have been studied with respect to BET surface (before and after reduction), O/sub 2/ chemisorption at -78/sup 0/C, redox behavior at 500/sup 0/C, and activity for cyclohexane dehydrogenation at 500/sup 0/C. In connection with the fate of tin catalysts during coal liquefaction, calculations have been made of the relative thermodynamic stability of SnCl/sub 2/, Sn, SnO/sub 2/, and SnS in the presence of H/sub 2/, HCl, H/sub 2/S and H/sub 2/O. Ferrous sulfate dispersed in methylnaphthalene has been shown to be reduced to ferrous sulfide under typical coal hydroliquefaction conditions (1 hour, 450/sup 0/C, 1000 psi initial p/sub H/sub 2//). This suggests that ferrous sulfide may be the common catalytic ingredient when either (a) ferrous sulfate impregnated on powdered coal, or (b) finely divided iron pyrite is used as the catalyst. Old research on impregnated ferrous sulfate, impregnated ferrous halides, and pyrite is consistent with this assumption. Eight Co/Mo/Al/sub 2/O/sub 3/ catalysts from commercial suppliers, along with SnCl/sub 2/, have been studied for the hydrotreating of 1-methylnaphthalene (1-MN) in a stirred autoclave at 450 and 500/sup 0/C.

  14. Atomically Precise Metal Nanoclusters for Catalytic Application

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Rongchao [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2016-11-18

    The central goal of this project is to explore the catalytic application of atomically precise gold nanoclusters. By solving the total structures of ligand-protected nanoclusters, we aim to correlate the catalytic properties of metal nanoclusters with their atomic/electronic structures. Such correlation unravel some fundamental aspects of nanocatalysis, such as the nature of particle size effect, origin of catalytic selectivity, particle-support interactions, the identification of catalytically active centers, etc. The well-defined nanocluster catalysts mediate the knowledge gap between single crystal model catalysts and real-world conventional nanocatalysts. These nanoclusters also hold great promise in catalyzing certain types of reactions with extraordinarily high selectivity. These aims are in line with the overall goals of the catalytic science and technology of DOE and advance the BES mission “to support fundamental research to understand, predict, and ultimately control matter and energy at the level of electrons, atoms, and molecules”. Our group has successfully prepared different sized, robust gold nanoclusters protected by thiolates, such as Au25(SR)18, Au28(SR)20, Au38(SR)24, Au99(SR)42, Au144(SR)60, etc. Some of these nanoclusters have been crystallographically characterized through X-ray crystallography. These ultrasmall nanoclusters (< 2 nm diameter) exhibit discrete electronic structures due to quantum size effect, as opposed to quasicontinuous band structure of conventional metal nanoparticles or bulk metals. The available atomic structures (metal core plus surface ligands) of nanoclusters serve as the basis for structure-property correlations. We have investigated the unique catalytic properties of nanoclusters (i.e. not observed in conventional nanogold catalysts) and revealed the structure-selectivity relationships. Highlights of our

  15. A novel liquid system of catalytic hydrogenation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    On the basis that endothermic aqueous-phase reforming of oxygenated hydrocarbons for H2 production and exothermic liquid phase hydrogenation of organic compounds are carried out under extremely close conditions of temperature and pressure over the same type of catalyst, a novel liquid system of catalytic hydrogenation has been proposed, in which hydrogen produced from aqueous-phase reforming of oxygenated hydrocarbons is in situ used for liquid phase hydrogenation of organic compounds. The usage of active hydrogen generated from aqueous-phase reforming of oxygenated hydrocarbons for liquid catalytic hydrogenation of organic compounds could lead to increasing the selectivity to H2 in the aqueous-phase reforming due to the prompt removal of hydrogen on the active centers of the catalyst. Meanwhile, this novel liquid system of catalytic hydrogenation might be a potential method to improve the selectivity to the desired product in liquid phase catalytic hydrogenation of organic compounds. On the other hand, for this novel liquid system of catalytic hydrogenation, some special facilities for H2 generation, storage and transportation in traditional liquid phase hydrogenation industry process are yet not needed. Thus, it would simplify the working process of liquid phase hydrogenation and increase the energy usage and hydrogen productivity.

  16. Catalytic Combustor for Fuel-Flexible Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Laster, W. R.; Anoshkina, E.

    2008-01-31

    Under the sponsorship of the U. S. Department of Energy’s National Energy Technology Laboratory, Siemens Westinghouse has conducted a three-year program to develop an ultra low NOx, fuel flexible catalytic combustor for gas turbine application in IGCC. The program is defined in three phases: Phase 1- Implementation Plan, Phase 2- Validation Testing and Phase 3 – Field Testing. Both Phase 1 and Phase 2 of the program have been completed. In IGCC power plants, the gas turbine must be capable of operating on syngas as a primary fuel and an available back-up fuel such as natural gas. In this program the Rich Catalytic Lean (RCLTM) technology is being developed as an ultra low NOx combustor. In this concept, ultra low NOx is achieved by stabilizing a lean premix combustion process by using a catalytic reactor to oxidize a portion of the fuel, increasing the temperature of fuel/air mixture prior to the main combustion zone. In Phase 1, the feasibility of the catalytic concept for syngas application has been evaluated and the key technology issues identified. In Phase II the technology necessary for the application of the catalytic concept to IGCC fuels was developed through detailed design and subscale testing. Phase III (currently not funded) will consist of full-scale combustor basket testing on natural gas and syngas.

  17. Catalytic Combustor for Fuel-Flexible Turbine

    Energy Technology Data Exchange (ETDEWEB)

    W. R. Laster; E. Anoshkina

    2008-01-31

    Under the sponsorship of the U. S. Department of Energy's National Energy Technology Laboratory, Siemens Westinghouse has conducted a three-year program to develop an ultra low NOx, fuel flexible catalytic combustor for gas turbine application in IGCC. The program is defined in three phases: Phase 1 - Implementation Plan, Phase 2 - Validation Testing and Phase 3 - Field Testing. Both Phase 1 and Phase 2 of the program have been completed. In IGCC power plants, the gas turbine must be capable of operating on syngas as a primary fuel and an available back-up fuel such as natural gas. In this program the Rich Catalytic Lean (RCLTM) technology is being developed as an ultra low NOx combustor. In this concept, ultra low NOx is achieved by stabilizing a lean premix combustion process by using a catalytic reactor to oxidize a portion of the fuel, increasing the temperature of fuel/air mixture prior to the main combustion zone. In Phase 1, the feasibility of the catalytic concept for syngas application has been evaluated and the key technology issues identified. In Phase II the technology necessary for the application of the catalytic concept to IGCC fuels was developed through detailed design and subscale testing. Phase III (currently not funded) will consist of full-scale combustor basket testing on natural gas and syngas.

  18. Electro Catalytic Oxidation (ECO) Operation

    Energy Technology Data Exchange (ETDEWEB)

    Morgan Jones

    2011-03-31

    The power industry in the United States is faced with meeting many new regulations to reduce a number of air pollutants including sulfur dioxide, nitrogen oxides, fine particulate matter, and mercury. With over 1,000 power plants in the US, this is a daunting task. In some cases, traditional pollution control technologies such as wet scrubbers and SCRs are not feasible. Powerspan's Electro-Catalytic Oxidation, or ECO{reg_sign} process combines four pollution control devices into a single integrated system that can be installed after a power plant's particulate control device. Besides achieving major reductions in emissions of sulfur dioxide (SO{sub 2}), nitrogen oxides (NOx), fine particulate matter (PM2.5) and mercury (Hg), ECO produces a highly marketable fertilizer, which can help offset the operating costs of the process system. Powerspan has been operating a 50-MW ECO commercial demonstration unit (CDU) at FirstEnergy Corp.'s R.E. Burger Plant near Shadyside, Ohio, since February 2004. In addition to the CDU, a test loop has been constructed beside the CDU to demonstrate higher NOx removal rates and test various scrubber packing types and wet ESP configurations. Furthermore, Powerspan has developed the ECO{reg_sign}{sub 2} technology, a regenerative process that uses a proprietary solvent to capture CO{sub 2} from flue gas. The CO{sub 2} capture takes place after the capture of NOx, SO{sub 2}, mercury, and fine particulate matter. Once the CO{sub 2} is captured, the proprietary solution is regenerated to release CO{sub 2} in a form that is ready for geological storage or beneficial use. Pilot scale testing of ECO{sub 2} began in early 2009 at FirstEnergy's Burger Plant. The ECO{sub 2} pilot unit is designed to process a 1-MW flue gas stream and produce 20 tons of CO{sub 2} per day, achieving a 90% CO{sub 2} capture rate. The ECO{sub 2} pilot program provided the opportunity to confirm process design and cost estimates, and prepare for large

  19. Catalytic microreactors for portable power generation

    Energy Technology Data Exchange (ETDEWEB)

    Karagiannidis, Symeon [Paul Scherer Institute, Villigen (Switzerland)

    2011-07-01

    ''Catalytic Microreactors for Portable Power Generation'' addresses a problem of high relevance and increased complexity in energy technology. This thesis outlines an investigation into catalytic and gas-phase combustion characteristics in channel-flow, platinum-coated microreactors. The emphasis of the study is on microreactor/microturbine concepts for portable power generation and the fuels of interest are methane and propane. The author carefully describes numerical and experimental techniques, providing a new insight into the complex interactions between chemical kinetics and molecular transport processes, as well as giving the first detailed report of hetero-/homogeneous chemical reaction mechanisms for catalytic propane combustion. The outcome of this work will be widely applied to the industrial design of micro- and mesoscale combustors. (orig.)

  20. Catalytic nanoarchitectonics for environmentally compatible energy generation

    Directory of Open Access Journals (Sweden)

    Hideki Abe

    2016-01-01

    Full Text Available Environmentally compatible energy management is one of the biggest challenges of the 21st century. Low-temperature conversion of chemical to electrical energy is of particular importance to minimize the impact to the environment while sustaining the consumptive economy. In this review, we shed light on one of the most versatile energy-conversion technologies: heterogeneous catalysts. We establish the integrity of structural tailoring in heterogeneous catalysts at different scales in the context of an emerging paradigm in materials science: catalytic nanoarchitectonics. Fundamental backgrounds of energy-conversion catalysis are first provided together with a perspective through state-of-the-art energy-conversion catalysis including catalytic exhaust remediation, fuel-cell electrocatalysis and photosynthesis of solar fuels. Finally, the future evolution of catalytic nanoarchitectonics is overviewed: possible combinations of heterogeneous catalysts, organic molecules and even enzymes to realize reaction-selective, highly efficient and long-life energy conversion technologies which will meet the challenge we face.

  1. Gene targeting of CK2 catalytic subunits

    Science.gov (United States)

    Lou, David Y.; Toselli, Paul; Landesman-Bollag, Esther; Dominguez, Isabel

    2013-01-01

    Protein kinase CK2 is a highly conserved and ubiquitous serine–threonine kinase. It is a tetrameric enzyme that is made up of two regulatory CK2β subunits and two catalytic subunits, either CK2α/CK2α, CK2α/ CK2α′, or CK2α′/CK2α′. Although the two catalytic subunits diverge in their C termini, their enzymatic activities are similar. To identify the specific function of the two catalytic subunits in development, we have deleted them individually from the mouse genome by homologous recombination. We have previously reported that CK2α′is essential for male germ cell development, and we now demonstrate that CK2α has an essential role in embryogenesis, as mice lacking CK2α die in mid-embryogenesis, with cardiac and neural tube defects. PMID:18594950

  2. Reactivity of organic compounds in catalytic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Minachev, Kh.M.; Bragin, O.V.

    1978-01-01

    A comprehensive review of 1976 Soviet research on catalysis delivered to the 1977 annual session of the USSR Academy of Science Council on Catalysis (Baku 6/16-20/77) covers hydrocarbon reactions, including hydrogenation and hydrogenolysis, dehydrogenation, olefin dimerization and disproportionation, and cyclization and dehydrocyclization (e.g., piperylene cyclization and ethylene cyclotrimerization); catalytic and physicochemical properties of zeolites, including cracking, dehydrogenation, and hydroisomerization catalytic syntheses and conversion of heterocyclic and functional hydrocarbon derivatives, including partial and total oxidation (e.g., of o-xylene to phthalic anhydride); syntheses of thiophenes from alkanes and hydrogen sulfide over certain dehydrogenation catalysts; catalytic syntheses involving carbon oxides ( e.g., the development of a new heterogeneous catalyst for hydroformylation of olefins), and of Co-MgO zeolitic catalysts for synthesis of aliphatic hydrocarbons from carbon dioxide and hydrogen, and fabrication of high-viscosity lubricating oils over bifunctional aluminosilicate catalysts.

  3. Catalytic Organic Transformations Mediated by Actinide Complexes

    Directory of Open Access Journals (Sweden)

    Isabell S. R. Karmel

    2015-10-01

    Full Text Available This review article presents the development of organoactinides and actinide coordination complexes as catalysts for homogeneous organic transformations. This chapter introduces the basic principles of actinide catalysis and deals with the historic development of actinide complexes in catalytic processes. The application of organoactinides in homogeneous catalysis is exemplified in the hydroelementation reactions, such as the hydroamination, hydrosilylation, hydroalkoxylation and hydrothiolation of alkynes. Additionally, the use of actinide coordination complexes for the catalytic polymerization of α-olefins and the ring opening polymerization of cyclic esters is presented. The last part of this review article highlights novel catalytic transformations mediated by actinide compounds and gives an outlook to the further potential of this field.

  4. Gene targeting of CK2 catalytic subunits.

    Science.gov (United States)

    Seldin, David C; Lou, David Y; Toselli, Paul; Landesman-Bollag, Esther; Dominguez, Isabel

    2008-09-01

    Protein kinase CK2 is a highly conserved and ubiquitous serine-threonine kinase. It is a tetrameric enzyme that is made up of two regulatory CK2beta subunits and two catalytic subunits, either CK2alpha/CK2alpha, CK2alpha/CK2alpha', or CK2alpha'/CK2alpha'. Although the two catalytic subunits diverge in their C termini, their enzymatic activities are similar. To identify the specific function of the two catalytic subunits in development, we have deleted them individually from the mouse genome by homologous recombination. We have previously reported that CK2alpha' is essential for male germ cell development, and we now demonstrate that CK2alpha has an essential role in embryogenesis, as mice lacking CK2alpha die in mid-embryogenesis, with cardiac and neural tube defects.

  5. Temperature modulation of a catalytic gas sensor.

    Science.gov (United States)

    Brauns, Eike; Morsbach, Eva; Kunz, Sebastian; Baeumer, Marcus; Lang, Walter

    2014-10-29

    The use of catalytic gas sensors usually offers low selectivity, only based on their different sensitivities for various gases due to their different heats of reaction. Furthermore, the identification of the gas present is not possible, which leads to possible misinterpretation of the sensor signals. The use of micro-machined catalytic gas sensors offers great advantages regarding the response time, which allows advanced analysis of the sensor response. By using temperature modulation, additional information about the gas characteristics can be measured and drift effects caused by material shifting or environmental temperature changes can be avoided. In this work a miniaturized catalytic gas sensor which offers a very short response time (electronic device was developed, since theory shows that harmonics induced by the electronics must be avoided to generate a comprehensible signal.

  6. Highly Dense Isolated Metal Atom Catalytic Sites

    DEFF Research Database (Denmark)

    Chen, Yaxin; Kasama, Takeshi; Huang, Zhiwei

    2015-01-01

    Atomically dispersed noble-metal catalysts with highly dense active sites are promising materials with which to maximise metal efficiency and to enhance catalytic performance; however, their fabrication remains challenging because metal atoms are prone to sintering, especially at a high metal...... loading. A dynamic process of formation of isolated metal atom catalytic sites on the surface of the support, which was achieved starting from silver nanoparticles by using a thermal surface-mediated diffusion method, was observed directly by using in situ electron microscopy and in situ synchrotron X......-ray diffraction. A combination of electron microscopy images with X-ray absorption spectra demonstrated that the silver atoms were anchored on five-fold oxygen-terminated cavities on the surface of the support to form highly dense isolated metal active sites, leading to excellent reactivity in catalytic oxidation...

  7. Effect of BaO on Catalytic Activity of Pt-Rh TWC

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effects of BaO doping on the three-way catalytic activity of Pt-Rh catalyst and on water-gas shift were investigated. The results show that the light-off temperatures of hydrocarbon and carbon monoxide and nitrogen oxides of the fresh catalysts slightly differ from those of the aged catalysts, and the catalysts containing CeO2-ZrO2-BaO have lower lightoff temperature and better catalytic activity than these containing BaO and CeO2-ZrO2 after hydrothermal aging for 5 h at 1000 C. The catalysts were characterized by means of the temperature-programmed reduction (TPR) in hydrogen and the temperature-programmed desorption (TPD) in oxygen. It is confirmed that the suggested route of CeO2-ZrO2-BaO by coprecipitation can improve the catalytic activity of catalysts.

  8. Pt/Al₂O₃-catalytic deoxygenation for upgrading of Leucaena leucocephala-pyrolysis oil.

    Science.gov (United States)

    Payormhorm, Jiraporn; Kangvansaichol, Kunn; Reubroycharoen, Presert; Kuchonthara, Prapan; Hinchiranan, Napida

    2013-07-01

    The aim of this study was to improve the quality of bio-oil produced from the pyrolysis of Leucaena leucocephala trunks via catalytic deoxygenation using Pt/Al2O3 (Pt content=1.32% (w/w)). The minimum molar ratio of oxygen/carbon (O/C) at 0.14 was achieved when the amount of catalyst was 10% (w/w, bio-oil) and was applied under 4 bar of initial nitrogen pressure at 340°C for 1h. The reaction mechanism of the catalytic deoxygenation, in terms of reforming, water-gas shift and dehydration reactions, was proposed. To consider the effect of different biomass types on the efficiency of catalytic deoxygenation, the bio-oils obtained from the pyrolysis of sawdust, rice straw and green microalgae were likewise evaluated for direct comparison.

  9. Porous media for catalytic renewable energy conversion

    Science.gov (United States)

    Hotz, Nico

    2012-05-01

    A novel flow-based method is presented to place catalytic nanoparticles into a reactor by sol-gelation of a porous ceramic consisting of copper-based nanoparticles, silica sand, ceramic binder, and a gelation agent. This method allows for the placement of a liquid precursor containing the catalyst into the final reactor geometry without the need of impregnating or coating of a substrate with the catalytic material. The so generated foam-like porous ceramic shows properties highly appropriate for use as catalytic reactor material, e.g., reasonable pressure drop due to its porosity, high thermal and catalytic stability, and excellent catalytic behavior. The catalytic activity of micro-reactors containing this foam-like ceramic is tested in terms of their ability to convert alcoholic biofuel (e.g. methanol) to a hydrogen-rich gas mixture with low concentrations of carbon monoxide (up to 75% hydrogen content and less than 0.2% CO, for the case of methanol). This gas mixture is subsequently used in a low-temperature fuel cell, converting the hydrogen directly to electricity. A low concentration of CO is crucial to avoid poisoning of the fuel cell catalyst. Since conventional Polymer Electrolyte Membrane (PEM) fuel cells require CO concentrations far below 100 ppm and since most methods to reduce the mole fraction of CO (such as Preferential Oxidation or PROX) have CO conversions of up to 99%, the alcohol fuel reformer has to achieve initial CO mole fractions significantly below 1%. The catalyst and the porous ceramic reactor of the present study can successfully fulfill this requirement.

  10. Thermal and catalytic pyrolysis of plastic waste

    Directory of Open Access Journals (Sweden)

    Débora Almeida

    2016-02-01

    Full Text Available Abstract The amount of plastic waste is growing every year and with that comes an environmental concern regarding this problem. Pyrolysis as a tertiary recycling process is presented as a solution. Pyrolysis can be thermal or catalytical and can be performed under different experimental conditions. These conditions affect the type and amount of product obtained. With the pyrolysis process, products can be obtained with high added value, such as fuel oils and feedstock for new products. Zeolites can be used as catalysts in catalytic pyrolysis and influence the final products obtained.

  11. Catalytic gasification of oil-shales

    Energy Technology Data Exchange (ETDEWEB)

    Lapidus, A.; Avakyan, T. [I.M. Gubkin Russian State Univ. of Oil and Gas, Moscow (Russian Federation); Strizhakova, Yu. [Samara State Univ. (Russian Federation)

    2012-07-01

    Nowadays, the problem of complex usage of solid fossil fuels as raw materials for obtaining of motor fuels and chemical products is becoming increasingly important. A one of possible solutions of the problem is their gasification with further processing of gaseous and liquid products. In this work we have investigated the process of thermal and catalytic gasification of Baltic and Kashpir oil-shales. We have shown that, as compared with non-catalytic process, using of nickel catalyst in the reaction increases the yield of gas, as well as hydrogen content in it, and decreases the amount of liquid products. (orig.)

  12. Heterogeneous Catalytic Ozonization of Sulfosalicylic Acid

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper describes the potential of heterogeneous catalytic ozonization of sulfo-salicylic acid (SSal). It was found that catalytic ozonization in the presence of Mn-Zr-O (a modified manganese dioxide supported on silica gel) had significantly enhanced the removal rate (72%) of total organic carbon (TOC) compared with that of ozonization alone (19%). The efficient removal rate of TOC was probably due to increasing the adsorption ability of catalyst and accelerating decomposition of ozone to produce more powerful oxidants than ozone.

  13. Catalytic process for formaldehyde oxidation

    Science.gov (United States)

    Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); D'Ambrosia, Christine M. (Inventor)

    1996-01-01

    Disclosed is a process for oxidizing formaldehyde to carbon dioxide and water without the addition of energy. A mixture of formaldehyde and an oxidizing agent (e.g., ambient air containing formaldehyde) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

  14. Simultaneous determination of trace iron and aluminum by catalytic spectrophotometry based on a novel oxidation reaction of xylene cyanol FF.

    Science.gov (United States)

    Cai, Longfei; Xu, Chunxiu

    2008-06-01

    A new, simple, sensitive and selective method for the simultaneous determination of trace iron and aluminum by catalytic spectrophotometry was presented, based on the catalytic effects of iron and aluminum on the discoloring reaction of xylene cyanol FF proceeded by hydrogen peroxide and potassium periodate in weak nitric acid medium. No catalytic effect was obtained in the presence of hydrogen peroxide or potassium periodate only. With the conditional rate constants determined in reaction systems catalyzed by Al or Fe only, the concentrations of Fe and Al in the samples can be calculated. The method was applied to the simultaneous determination of trace Fe and Al in tap water, lake water, river water and tea leaves without separation and preconcentration.

  15. Degradation of paracetamol by catalytic wet air oxidation and sequential adsorption - Catalytic wet air oxidation on activated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Quesada-Penate, I. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France); Julcour-Lebigue, C., E-mail: carine.julcour@ensiacet.fr [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France); Jauregui-Haza, U.J. [Instituto Superior de Tecnologias y Ciencias Aplicadas, Ave. Salvador Allende y Luaces, Habana (Cuba); Wilhelm, A.M.; Delmas, H. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France)

    2012-06-30

    Highlights: Black-Right-Pointing-Pointer Three activated carbons (AC) compared as adsorbents and oxidation catalysts. Black-Right-Pointing-Pointer Similar evolution for catalytic and adsorptive properties of AC over reuses. Black-Right-Pointing-Pointer Acidic and mesoporous AC to be preferred, despite lower initial efficiency. Black-Right-Pointing-Pointer Oxidative degradation of paracetamol improves biodegradability. Black-Right-Pointing-Pointer Convenient hybrid adsorption-regenerative oxidation process for continuous treatment. - Abstract: The concern about the fate of pharmaceutical products has raised owing to the increasing contamination of rivers, lakes and groundwater. The aim of this paper is to evaluate two different processes for paracetamol removal. The catalytic wet air oxidation (CWAO) of paracetamol on activated carbon was investigated both as a water treatment technique using an autoclave reactor and as a regenerative treatment of the carbon after adsorption in a sequential fixed bed process. Three activated carbons (ACs) from different source materials were used as catalysts: two microporous basic ACs (S23 and C1) and a meso- and micro-porous acidic one (L27). During the first CWAO experiment the adsorption capacity and catalytic performance of fresh S23 and C1 were higher than those of fresh L27 despite its higher surface area. This situation changed after AC reuse, as finally L27 gave the best results after five CWAO cycles. Respirometry tests with activated sludge revealed that in the studied conditions the use of CWAO enhanced the aerobic biodegradability of the effluent. In the ADOX process L27 also showed better oxidation performances and regeneration efficiency. This different ageing was examined through AC physico-chemical properties.

  16. Assessment of the Vapor Phase Catalytic Ammonia Removal (VPCAR) Technology at the MSFC ECLS Test Facility

    Science.gov (United States)

    Tomes, Kristin; Long, David; Carter, Layne; Flynn, Michael

    2007-01-01

    The Vapor Phase Catalytic Ammonia. Removal (VPCAR) technology has been previously discussed as a viable option for. the Exploration Water Recovery System. This technology integrates a phase change process with catalytic oxidation in the vapor phase to produce potable water from exploration mission wastewaters. A developmental prototype VPCAR was designed, built and tested under funding provided by a National Research. Announcement (NRA) project. The core technology, a Wiped Film Rotating Device (WFRD) was provided by Water Reuse Technologies under the NRA, whereas Hamilton Sundstrand Space Systems International performed the hardware integration and acceptance test. of the system. Personnel at the-Ames Research Center performed initial systems test of the VPCAR using ersatz solutions. To assess the viability of this hardware for Exploration. Life Support (ELS) applications, the hardware has been modified and tested at the MSFC ECLS Test facility. This paper summarizes the hardware modifications and test results and provides an assessment of this technology for the ELS application.

  17. Removal of ammonia solutions used in catalytic wet oxidation processes.

    Science.gov (United States)

    Hung, Chang Mao; Lou, Jie Chung; Lin, Chia Hua

    2003-08-01

    Ammonia (NH(3)) is an important product used in the chemical industry, and is common place in industrial wastewater. Industrial wastewater containing ammonia is generally either toxic or has concentrations or temperatures such that direct biological treatment is unfeasible. This investigation used aqueous solutions containing more of ammonia for catalytic liquid-phase oxidation in a trickle-bed reactor (TBR) based on Cu/La/Ce composite catalysts, prepared by co-precipitation of Cu(NO(3))(2), La(NO(3))(2), and Ce(NO(3))(3) at 7:2:1 molar concentrations. The experimental results indicated that the ammonia conversion of the wet oxidation in the presence of the Cu/La/Ce composite catalysts was determined by the Cu/La/Ce catalyst. Minimal ammonia was removed from the solution by the wet oxidation in the absence of any catalyst, while approximately 91% ammonia removal was achieved by wet oxidation over the Cu/La/Ce catalyst at 230 degrees C with oxygen partial pressure of 2.0 MPa. Furthermore, the effluent streams were conducted at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes, and a reaction pathway was found linking the oxidizing ammonia to nitric oxide, nitrogen and water. The solution contained by-products, including nitrates and nitrites. Nitrite selectivity was minimized and ammonia removal maximized when the feed ammonia solution had a pH of around 12.0.

  18. Formation of catalytic silver nanoparticles supported on branched polyethyleneimine derivatives.

    Science.gov (United States)

    Signori, Aline M; Santos, Kelly de O; Eising, Renato; Albuquerque, Brunno L; Giacomelli, Fernando C; Domingos, Josiel B

    2010-11-16

    A new and straightforward method for screening highly catalytically active silver nanoparticle-polymer composites derived from branched polyethyleneimine (PEI) is reported. The one-step systematic derivatization of the PEI scaffold with alkyl (butyl or octyl) and ethanolic groups led to a structural diversity correlated to the stabilization of silver nanoparticles and catalysis. Analysis of PEI derivative libraries identified a silver nanoparticle-polymer composite that was able to efficiently catalyze the p-nitrophenol reduction by NaBH(4) in water with a rate constant normalized to the surface area of the nanoparticles per unit volume (k(1)) of 0.57 s(-1) m(-2) L. Carried out in the presence of excess NaBH(4), the catalytic reaction was observed to follow pseudo-first-order kinetics and the apparent rate constant was linearly dependent on the total surface area of the silver nanoparticles (Ag-NPs), indicating that catalysis takes place on the surface of the nanoparticles. All reaction kinetics presented induction periods, which were dependent on the concentration of substrates, the total surface of the nanoparticles, and the polymer composition. All data indicated that this induction time is related to the resistance to substrate diffusion through the polymer support. Hydrophobic effects are also assumed to play an important role in the catalysis, through an increase in the local substrate concentration.

  19. Copper on activated carbon for catalytic wet air oxidation

    Directory of Open Access Journals (Sweden)

    Nora Dolores Martínez

    2009-03-01

    Full Text Available Textile industry is an important source of water contamination. Some of the organic contaminants cannot be eliminated by nature in a reasonable period. Heterogeneous catalytic wet air oxidation is one of the most effective methods to purify wastewater with organic contaminants. In this work, catalysts based on copper supported on activated carbon were synthesized. The activated carbons were obtained from industrial wastes (apricot core and grape stalk of San Juan, Argentina. These were impregnated with a copper salt and thermically treated in an inert atmosphere. Analysis of specific surface, pore volume, p zc, acidity, basicity and XRD patterns were made in order to characterize the catalysts. The catalytic activity was tested in the oxidation of methylene blue (MB and polyvinyl alcohol (PVA in aqueous phase with pure oxygen. Reaction tests were carried out in a Parr batch reactor at different temperatures, with a 0.2 MPa partial pressure of oxygen. The amount of unconverted organics was measured by spectrophotometry. Higher temperatures were necessary for the degradation of PVA compared to those for methylene blue.

  20. Cobaloxime-based photo-catalytic devices for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Fihri, A.; Artero, V.; Razavet, M.; Baffert, C.; Fontecave, M. [CEA Grenoble, DSV, iRTSV, Lab Chim et Biol Metaux, CNRS, UMR 5249, Univ Grenoble 1, F-38054 Grenoble 9 (France); Leibl, W. [CEA, DSV, iBiTecS, Lab Photocatalyse et Biohydrogene, CNRS, URA 2096, Gif Sur Yvette (France)

    2008-07-01

    In this paper is described the synthesis and activity of a series of novel hetero-dinuclear ruthenium-cobaloxime photo-catalysts able to achieve the photochemical production of hydrogen with the highest turnover numbers so far reported for such devices. First of all, substituting cobalt for rare and expensive platinum, palladium, or rhodium metals in photo-catalysts is a first step toward economically viable hydrogen production. Cobaloximes appear to be good candidates for H{sub 2}-evolving catalysts, and they may provide a good basis for the design of photo-catalysts that function in pure water as both the solvent and the sustainable proton source. Secondly, a molecular connection between the sensitizer and the H{sub 2}-evolving catalyst seems to provide advantages regarding the photo-catalytic activity. Structural modifications of this connection should allow a better tuning of the electron transfer between the light-harvesting unit and the catalytic center and thus an increase of the efficiency of the system. (O.M.)

  1. Plasma catalytic reforming of methane

    Energy Technology Data Exchange (ETDEWEB)

    Bromberg, L.; Cohn, D.R.; Rabinovich, A. [Massachusetts Inst. of Technology, Cambridge, MA (United States). Plasma Science and Fusion Center; Alexeev, N. [Russian Academy of Sciences, Moscow (Russian Federation). Baikov Inst. of Metallurgy

    1998-08-01

    Thermal plasma technology can be efficiently used in the production of hydrogen and hydrogen-rich gases from methane and a variety of fuels. This paper describes progress in plasma reforming experiments and calculations of high temperature conversion of methane using heterogeneous processes. The thermal plasma is a highly energetic state of matter that is characterized by extremely high temperatures (several thousand degrees Celsius) and high degree of dissociation and substantial degree of ionization. The high temperatures accelerate the reactions involved in the reforming process. Hydrogen-rich gas (50% H{sub 2}, 17% CO and 33% N{sub 2}, for partial oxidation/water shifting) can be efficiently made in compact plasma reformers. Experiments have been carried out in a small device (2--3 kW) and without the use of efficient heat regeneration. For partial oxidation/water shifting, it was determined that the specific energy consumption in the plasma reforming processes is 16 MJ/kg H{sub 2} with high conversion efficiencies. Larger plasmatrons, better reactor thermal insulation, efficient heat regeneration and improved plasma catalysis could also play a major role in specific energy consumption reduction and increasing the methane conversion. A system has been demonstrated for hydrogen production with low CO content ({approximately} 1.5%) with power densities of {approximately} 30 kW (H{sub 2} HHV)/liter of reactor, or {approximately} 10 m{sup 3}/hr H{sub 2} per liter of reactor. Power density should further increase with increased power and improved design.

  2. Electrochemical Promotion of Catalytic Reactions Using

    DEFF Research Database (Denmark)

    Petrushina, Irina; Bjerrum, Niels; Cleemann, Lars Nilausen

    2007-01-01

    This paper presents the results of a study on electrochemical promotion (EP) of catalytic reactions using Pt/C/polybenzimidazole(H3PO4)/Pt/C fuel cell performed by the Energy and Materials Science Group (Technical University of Denmark) during the last 6 years[1-4]. The development of our...... understanding of the nature of the electrochemical promotion is also presented....

  3. Shungite carbon catalytic effect on coal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Grigorieva, E.N.; Rozhkova, N.N. [Russian Academy of Sciences, Moscow (Russian Federation). Institute for High Temperature

    1999-07-01

    The catalytic ability of shungite carbon in reactions of coal organic matter models appeared to be due to its fullerene structure only. Transition metal sulphides present in shungite carbon are not active in the conditions of coal treatment. Shungite carbon was shown to exhibit an acceleration of thermolysis of coal and organic matter models, mainly dehydrogenation. 5 refs., 1 tabs.

  4. Catalytic site interactions in yeast OMP synthase

    DEFF Research Database (Denmark)

    Hansen, Michael Riis; Barr, Eric W.; Jensen, Kaj Frank;

    2014-01-01

    45 (2006) 5330-5342]. This behavior was investigated in the yeast enzyme by mutations in the conserved catalytic loop and 5-phosphoribosyl-1-diphosphate (PRPP) binding motif. Although the reaction is mechanistically sequential, the wild-type (WT) enzyme shows parallel lines in double reciprocal...

  5. Catalytic Amination of Alcohols, Aldehydes, and Ketones

    Science.gov (United States)

    Klyuev, M. V.; Khidekel', M. L.

    1980-01-01

    Data on the catalytic amination of alcohols and carbonyl compounds are examined, the catalysts for these processes are described, and the problems of their effectiveness, selectivity, and stability are discussed. The possible mechanisms of the reactions indicated are presented. The bibliography includes 266 references.

  6. Catalytic Asymmetric Synthesis of Phosphine Boronates.

    Science.gov (United States)

    Hornillos, Valentín; Vila, Carlos; Otten, Edwin; Feringa, Ben L

    2015-06-26

    The first catalytic enantioselective synthesis of ambiphilic phosphine boronate esters is presented. The asymmetric boration of α,β-unsaturated phosphine oxides catalyzed by a copper bisphosphine complex affords optically active organoboronate esters that bear a vicinal phosphine oxide group in good yields and high enantiomeric excess. The synthetic utility of the products is demonstrated through stereospecific transformations into multifunctional optically active compounds.

  7. SELECTIVE CATALYTIC REDUCTION MERCURY FIELD SAMPLING PROJECT

    Science.gov (United States)

    A lack of data still exists as to the effect of selective catalytic reduction (SCR), selective noncatalytic reduction (SNCR), and flue gas conditioning on the speciation and removal of mercury (Hg) at power plants. This project investigates the impact that SCR, SNCR, and flue gas...

  8. Performance characterization of a hydrogen catalytic heater.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Terry Alan; Kanouff, Michael P.

    2010-04-01

    This report describes the performance of a high efficiency, compact heater that uses the catalytic oxidation of hydrogen to provide heat to the GM Hydrogen Storage Demonstration System. The heater was designed to transfer up to 30 kW of heat from the catalytic reaction to a circulating heat transfer fluid. The fluid then transfers the heat to one or more of the four hydrogen storage modules that make up the Demonstration System to drive off the chemically bound hydrogen. The heater consists of three main parts: (1) the reactor, (2) the gas heat recuperator, and (3) oil and gas flow distribution manifolds. The reactor and recuperator are integrated, compact, finned-plate heat exchangers to maximize heat transfer efficiency and minimize mass and volume. Detailed, three-dimensional, multi-physics computational models were used to design and optimize the system. At full power the heater was able to catalytically combust a 10% hydrogen/air mixture flowing at over 80 cubic feet per minute and transfer 30 kW of heat to a 30 gallon per minute flow of oil over a temperature range from 100 C to 220 C. The total efficiency of the catalytic heater, defined as the heat transferred to the oil divided by the inlet hydrogen chemical energy, was characterized and methods for improvement were investigated.

  9. The Catalytic Asymmetric Intramolecular Stetter Reaction.

    Science.gov (United States)

    de Alaniz, Javier Read; Rovis, Tomislav

    2009-05-01

    This account chronicles our efforts at the development of a catalytic asymmetric Stetter reaction using chiral triazolium salts as small molecule organic catalysts. Advances in the mechanistically related azolium-catalyzed asymmetric benzoin reaction are discussed, particularly as they apply to catalyst design. A chronological treatise of reaction discovery, catalyst optimization and reactivity extension follows.

  10. 碳质材料催化臭氧氧化去除水中溶解性有机物的研究进展%Catalytic ozonation based on carbon materials for removing dissolved organic compounds from water:A review

    Institute of Scientific and Technical Information of China (English)

    钱飞跃; 王翻翻; 刘小朋; 李月寒; 王建芳

    2015-01-01

    Catalytic ozonation based on carbon materials labeled as CMs/O3 was well characterized by superior organics removal,high ozone utilization and without metal leaching;however,most of them were still at the stage of laboratory research,since a stable catalytic property of CMs could not be expected after a long running. In this paper,the main reaction mechanisms in CMs/O3 system for removing dissolved organics from water,both surface catalytic oxidation and hydroxyl radicals (HO·)oxidation in bulk solution were discussed and the influences of critical factors in heterogeneous reaction pathways and organics removal efficiency were elaborated. It was pointed out that the consumption of basic active sites and the accumulation of acid oxygen-containing groups on the surface were considered to cause a partial deactivation of CMs in cyclic experiments. In addition,using mesoporous catalyst,optimizing pH and normalized ozone dosage,could help in reducing internal mass transfer resistances,thus enhance target organics removal. This paper reviewed the recent advances of CMs/O3 applied in model organic pollutants removal and industrial wastewater treatment. Multi-walled carbon nanotube ( MWCNT ) and the innovative loading technology could improve CMs/O3 performances in deep purification of micro-polluted water body. Coupling mature treatment methods and CMs/O3 in an efficient and low-cost process was proposed as the important direction of further study.%碳质材料催化臭氧氧化(CMs/O3)体系具有除污性能强、臭氧利用率高和无金属溶出的特点,但受制于CMs催化性能的易失性,该方法目前仍处于实验室研发阶段。本文系统阐述了CMs/O3体系的反应原理,并认为表面催化氧化与均相羟自由基(HO·)反应是去除水中溶解性有机物的主要途径;详细分析了影响非均相反应机理与体系处理效能的关键因素,并指出在反应过程中,碳表面碱性活性点位的消耗与酸性

  11. Fundamentals and Catalytic Applications of CeO2-Based Materials.

    Science.gov (United States)

    Montini, Tiziano; Melchionna, Michele; Monai, Matteo; Fornasiero, Paolo

    2016-05-25

    Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40(th) anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three-way catalysts (TWCs). Apart from this well-established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2-based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water-gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2-based materials has already been acquired, new characterization techniques and powerful theoretical methods are deepening our understanding of these materials, helping us to predict their behavior and application potential. This review has a wide view on all those aspects related to ceria which promise to produce an important impact on our life, encompassing fundamental knowledge of CeO2 and its properties, characterization toolbox, emerging features, theoretical studies, and all the catalytic applications, organized by their degree of establishment on the market.

  12. Liquid-Phase Catalytic Hydrogenation of Furfural in Variable Solvent Media

    Institute of Scientific and Technical Information of China (English)

    夏淑倩; 李阳; 商巧燕; 张成武; 马沛生

    2016-01-01

    Water is the most abundant compound inherently existing in bio-oils. Thus understanding the role of water within bio-oils upgrading process is essential for future engineering scale-up design. In this study, furfural was chosen as bio-oils model compound, and the catalytic hydrogenation of furfural over commercial 5%, Ru/C catalyst was firstly investigated in a series of gradient variable water/ethanol mixture solvents. Water had a signifi-cant effect on the distribution of product yields. The dominant reaction pathways varied with the water contents in the water/ethanol mixture solvents. Typically, when ethanol was used as the solvent, the main products were ob-tained by the hydrogenation of carbonyl group or furan ring. When pure water was used as the solvent, the rear-rangement reaction of furfural to cyclopentanone should be selectively promoted theoretically. However, serious polymerization and resinification were observed herein in catalytic hydrogenation system of pure water. The cata-lyst surface was modified by the water-insoluble polymers, and consequently, a relative low yield of cyclopenta-none was obtained. A plausible multiple competitive reaction mechanism between polymerization reaction and the hydrogenation of furfural was suggested in this study. Characterizations(TG,FT-IR,SEM)were employed to analyze and explain our experiments.

  13. Degradation of paracetamol by catalytic wet air oxidation and sequential adsorption - Catalytic wet air oxidation on activated carbons.

    Science.gov (United States)

    Quesada-Peñate, I; Julcour-Lebigue, C; Jáuregui-Haza, U J; Wilhelm, A M; Delmas, H

    2012-06-30

    The concern about the fate of pharmaceutical products has raised owing to the increasing contamination of rivers, lakes and groundwater. The aim of this paper is to evaluate two different processes for paracetamol removal. The catalytic wet air oxidation (CWAO) of paracetamol on activated carbon was investigated both as a water treatment technique using an autoclave reactor and as a regenerative treatment of the carbon after adsorption in a sequential fixed bed process. Three activated carbons (ACs) from different source materials were used as catalysts: two microporous basic ACs (S23 and C1) and a meso- and micro-porous acidic one (L27). During the first CWAO experiment the adsorption capacity and catalytic performance of fresh S23 and C1 were higher than those of fresh L27 despite its higher surface area. This situation changed after AC reuse, as finally L27 gave the best results after five CWAO cycles. Respirometry tests with activated sludge revealed that in the studied conditions the use of CWAO enhanced the aerobic biodegradability of the effluent. In the ADOX process L27 also showed better oxidation performances and regeneration efficiency. This different ageing was examined through AC physico-chemical properties.

  14. Asymmetric Catalytic Reactions Catalyzed by Chiral Titanium Complexes

    Institute of Scientific and Technical Information of China (English)

    FENG XiaoMing

    2001-01-01

    @@ Chiral titanium complexes is very importance catalyst to asymmetric catalytic reactions. A series of catalytic systems based on titanium-chiral ligands complexes has been reported. This presentation will discuss some of our recent progress on asymmetric catalytic reactions catalyzed by chiral titanium complexes.

  15. Asymmetric Catalytic Reactions Catalyzed by Chiral Titanium Complexes

    Institute of Scientific and Technical Information of China (English)

    FENG; XiaoMing

    2001-01-01

    Chiral titanium complexes is very importance catalyst to asymmetric catalytic reactions. A series of catalytic systems based on titanium-chiral ligands complexes has been reported. This presentation will discuss some of our recent progress on asymmetric catalytic reactions catalyzed by chiral titanium complexes.  ……

  16. ZEOLITES: EFFECTIVE WATER PURIFIERS

    Science.gov (United States)

    Zeolites are known for their adsorption, ion exchange and catalytic properties. Various natural zeolites are used as odor and moisture adsorbents and water softeners. Due to their acidic nature, synthetic zeolites are commonly employed as solid acid catalysts in petrochemical ind...

  17. Molecular dynamics simulation and conformational analysis of some catalytically active peptides.

    Science.gov (United States)

    Honarparvar, Bahareh; Skelton, Adam A

    2015-04-01

    The design of stable and inexpensive artificial enzymes with potent catalytic activity is a growing field in peptide science. The first step in this design process is to understand the key factors that can affect the conformational preference of an enzyme and correlate them with its catalytic activity. In this work, molecular dynamics simulations in explicit water of two catalytically active peptides (peptide 1: Fmoc-Phe1-Phe2-His-CONH2; peptide 2: Fmoc-Phe1-Phe2-Arg-CONH2) were performed at temperatures of 300, 400, and 500 K. Conformational analysis of these peptides using Ramachandran plots identified the secondary structures of the amino acid residues involved (Phe1, Phe2, His, Arg) and confirmed their conformational flexibility in solution. Furthermore, Ramachandran maps revealed the intrinsic preference of the constituent residues of these compounds for a helical conformation. Long-range interaction distances and radius of gyration (R g) values obtained during 20 ns MD simulations confirmed their tendency to form folded conformations. Results showed a decrease in side-chain (Phe1, Phe2, His ring, and Arg) contacts as the temperature was raised from 300 to 400 K and then to 500 K. Finally, the radial distribution functions (RDF) of the water molecules around the nitrogen atoms in the catalytically active His and Arg residues of peptide 1 and peptide 2 revealed that the strongest water-peptide interaction occurred with the arginine nitrogen atoms in peptide 2. Our results highlight differences in the secondary structures of the two peptides that can be explained by the different arrangement of water molecules around the nitrogen atoms of Arg in peptide 2 as compared to the arrangement of water molecules around the nitrogen atoms of His in peptide 1. The results of this work thus provide detailed insight into peptide conformations which can be exploited in the future design of peptide analogs.

  18. 水相生物油选择性加氢-催化裂解制取烯烃和芳香烃的试验研究%Experimental Research on Selective Hydrogenation-Catalytic Pyrolysis of Water-Soluble Bio-Oil to Produce Olefins and Aromatics

    Institute of Scientific and Technical Information of China (English)

    张会岩; 肖睿; GeorgeWHuber

    2012-01-01

    本文在气相流动反应器中采用ZSM-5催化剂对水相选择性加氢生物油进行了催化裂解试验研究。主要考察了反应温度、质量空速、油分压和原料油组分含量对产物产率和选择性的影响。结果表明,选择性加氢生物油转化为石油化工用品(烯烃和芳香烃)的最优工况为:反应温度,600°C;质量空速,11.7h-1;油分压,6693Pa;油组分含量,12.5%。在此工况下,石油化工用品达到最高碳产率76.0%,其中烯烃57.6%,芳香烃18.4%。烯烃和芳香烃的产率及其主要成分的选择性可以根据市场的需求通过调节反应条件来改变。%Catalytic pyrolysis of selectively hydrogenated water-soluble bio-oil was carried out in a gas flow reactor with ZSM-5 catalyst. The effect of temperature, weight hourly space velocity, oil partial pressure in gas phase and oil content in the feed on product yields and selectivities were studied. The results show that the optimizing conditions for petrochemicals (olefins and aromatics) production were: temperature, 600~C; WHSV, 11.7 h-1, oil partial pressure, 6693 Pa; oil content, 12.5%. The maximum yield of petrochemicals is 76.0%, including 57.6% olefins and 18.4% aromatics. The olefins and aromatics yields and their main components selectivities can be adjusted by changing the reaction conditions according to market requirements.

  19. Co-Mn-Al层状双氢氧化物催化臭氧氧化水中有机污染物的活性%Catalytic Performance of Layered Double Hydroxides Co-Mn-Al for Ozonation of Organic Pollutants in Water

    Institute of Scientific and Technical Information of China (English)

    隋铭皓; 段标标; 盛力; 黄书杭; 佘磊

    2012-01-01

    采用共沉淀法制备了Co-Mn-Al层状双氢氧化物,并将其用于以硝基苯为目标污染物的催化臭氧降解反应中.结果表明,Co-Mn-Al层状双氢氧化物存在时,硝基苯的降解和矿化效率较单独臭氧氧化系统显著提高.采用加入羟基自由基捕获剂(叔丁醇)和电子顺磁共振检测(5,5-二甲基-1-吡咯啉-N-氧化物为捕获剂)的间接、直接方法,探讨了Co-Mn-Al层状双氢氧化物是否强化了羟基自由基的生成.结果表明,加入叔丁醇降低了硝基苯的降解效率;电子顺磁共振检出了更强的羟基自由基加成物生成信号.Co-Mn-Al层状双氢氧化物的存在促进了羟基自由基的生成.%The catalytic activity of layered double hydroxides containing Co,Mn,and Al for the ozonation of organic pollutants in water was investigated.The Co-Mn-Al layered double hydroxides were prepared by coprecipitation.Nitrobenzene was used as a model compound,and it was shown that the degradation and mineralization of nitrobenzene was increased by the presence of Co-Mn-Al layered double hydroxides as compared to ozonation alone.Both an indirect method of adding a scavenger (tert-butanol) of the hydroxyl radical chain reaction and direct electron spin resonance using 5,5-dimethyl-1-pyrroline-N-oxide as a spin trapping agent were used to investigate the generation of hydroxyl radicals in the ozonation by the Co-Mn-A1layered double hydroxides.The inhibiting effect of tert-butanol on the degradation of nitrobenzene and the detection of the stronger 5,5-dimethyl-1-pyrroline-N-oxide/hydroxyl radical adduct showed that the Co-Mn-Al layered double hydroxides catalyzed the generation of hydroxyl radicals.

  20. Assessment of uncertainty in determination of water iodide level by As3+-Ce4+ catalytic spectrophotometry%生活饮用水中碘化物的砷铈催化分光光度法的不确定度评估

    Institute of Scientific and Technical Information of China (English)

    李鹏; 姜延国; 李力军; 王丹; 张兆瑞; 胡欣新

    2015-01-01

    目的 建立生活饮用水中碘化物的砷铈催化分光光度法的测量不确定度评估方案,评定测定结果的质量和主要影响因素;建立该方法工作曲线的变动性不确定度评估计算公式;建立移液器带来的不确定度评估方案.方法 按照《适合缺碘及高碘地区水碘检测的方法研究》方法要求,从测量的重复性、工作曲线的变动性、标准溶液的不确定度和样品溶液体积不确定度等方面,分析两个浓度的国家标准样品(GBW09114c、GBW09113c)不确定度分量.结果 国家标准样品GBW09114c和GBW09113c中碘化物浓度经修约后分别为(61.3±1.4)、(8.1±0.3)μg/L;相对扩展不确定度RU和RU2分别为2.25%、3.46%,均在标准物质证书允许的误差范围内(10.0%、14.8%).测量的重复性、标准溶液的不确定度中碘化钾基准试药不确定度、玻璃器材不确定度、样品溶液体积不确定度中移液器不确定度为主要影响因子;提出了更符合检测实际工作曲线的变动性不确定度计算公式;将温度影响因素和操作重复性引入移液器的不确定度讨论中.结论 此方法适用于评估生活饮用水中碘化物的砷铈催化分光光度法的不确定度.%Objective We set up an uncertainty assessment method for determination of iodides in water by As3+-Ce4+ catalytic spectrophotometry, in order to assess the accuracy of the method and the major influencing factors, and to build up an equation to assess the uncertainty in the mobility of working curve and an uncertainty assessment method for pipettors.Methods According to "Methods for Water Iodine Detection Suitable for Iodine Deficiency and Iodine Excess Areas", the uncertainty items of the two standard materials (GBW09114c and GBW09113c) in different concentrations, such as repeatability of measurement, the mobility of working curve, the uncertainty of standard solution and sample solution, etc, were analyzed.Results The contents of

  1. Analysis of the Staphylococcus aureus DgkB structure reveals a common catalytic mechanism for the soluble diacylglycerol kinases.

    Science.gov (United States)

    Miller, Darcie J; Jerga, Agoston; Rock, Charles O; White, Stephen W

    2008-07-01

    Soluble diacylglycerol (DAG) kinases function as regulators of diacylglycerol metabolism in cell signaling and intermediary metabolism. We report the structure of a DAG kinase, DgkB from Staphylococcus aureus, both as the free enzyme and in complex with ADP. The molecule is a tight homodimer, and each monomer comprises two domains with the catalytic center located within the interdomain cleft. Two distinctive features of DkgB are a structural Mg2+ site and an associated Asp*water*Mg2+ network that extends toward the active site locale. Site-directed mutagenesis revealed that these features play important roles in the catalytic mechanism. The key active site residues and the components of the Asp*water*Mg2+ network are conserved in the catalytic cores of the mammalian signaling DAG kinases, indicating that these enzymes use the same mechanism and have similar structures as DgkB.

  2. Analysis of the Staphylococcus aureus DgkB Structure Reveals a Common Catalytic Mechanism for the Soluble Diacylglycerol Kinases

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Darcie J.; Jerga, Agoston; Rock, Charles O.; White, Stephen W. (SJCH)

    2008-08-11

    Soluble diacylglycerol (DAG) kinases function as regulators of diacylglycerol metabolism in cell signaling and intermediary metabolism. We report the structure of a DAG kinase, DgkB from Staphylococcus aureus, both as the free enzyme and in complex with ADP. The molecule is a tight homodimer, and each monomer comprises two domains with the catalytic center located within the interdomain cleft. Two distinctive features of DkgB are a structural Mg{sup 2+} site and an associated Asp{center_dot}water{center_dot}Mg{sup 2+} network that extends toward the active site locale. Site-directed mutagenesis revealed that these features play important roles in the catalytic mechanism. The key active site residues and the components of the Asp{center_dot}water{center_dot}Mg{sup 2+} network are conserved in the catalytic cores of the mammalian signaling DAG kinases, indicating that these enzymes use the same mechanism and have similar structures as DgkB.

  3. Janus droplet as a catalytic micromotor

    CERN Document Server

    Shklyaev, Sergey

    2015-01-01

    Self-propulsion of a Janus droplet in a solution of surfactant, which reacts on a half of a drop surface, is studied theoretically. The droplet acts as a catalytic motor creating a concentration gradient, which generates its surface-tension-driven motion; the self-propulsion speed is rather high, $60\\; {\\rm \\mu m/s}$ and more. This catalytic motor has several advantages over other micromotors: simple manufacturing, easily attained neutral buoyancy. In contrast to a single-fluid droplet, which demonstrates a self-propulsion as a result of symmetry breaking instability, for Janus one no stability threshold exists; hence, the droplet radius can be scaled down to micrometers. The paper was finalized and submitted by Denis S. Goldobin after Sergey Sklyaev had sadly passed away on June 2, 2014.

  4. Control of a catalytic fluid cracker

    Energy Technology Data Exchange (ETDEWEB)

    Arbel, A.; Huang, Z.; Rinard, I.; Shinnar, R.

    1993-12-13

    Control offers an important tool for savings in refineries, mainly by integration of process models into on-line control. This paper is part of a research effort to better understand problems of partial control; control of a Fluid Catalytic Cracker (FCC) is used as example. Goal is to understand better the control problems of an FCC in context of model based control of a refinery, and to understand the general problem of designing partial control systems.

  5. Materials for High-Temperature Catalytic Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ersson, Anders

    2003-04-01

    Catalytic combustion is an environmentally friendly technique to combust fuels in e.g. gas turbines. Introducing a catalyst into the combustion chamber of a gas turbine allows combustion outside the normal flammability limits. Hence, the adiabatic flame temperature may be lowered below the threshold temperature for thermal NO{sub X} formation while maintaining a stable combustion. However, several challenges are connected to the application of catalytic combustion in gas turbines. The first part of this thesis reviews the use of catalytic combustion in gas turbines. The influence of the fuel has been studied and compared over different catalyst materials. The material section is divided into two parts. The first concerns bimetallic palladium catalysts. These catalysts showed a more stable activity compared to their pure palladium counterparts for methane combustion. This was verified both by using an annular reactor at ambient pressure and a pilot-scale reactor at elevated pressures and flows closely resembling the ones found in a gas turbine combustor. The second part concerns high-temperature materials, which may be used either as active or washcoat materials. A novel group of materials for catalysis, i.e. garnets, has been synthesised and tested in combustion of methane, a low-heating value gas and diesel fuel. The garnets showed some interesting abilities especially for combustion of low-heating value, LHV, gas. Two other materials were also studied, i.e. spinels and hexa aluminates, both showed very promising thermal stability and the substituted hexa aluminates also showed a good catalytic activity. Finally, deactivation of the catalyst materials was studied. In this part the sulphur poisoning of palladium, platinum and the above-mentioned complex metal oxides has been studied for combustion of a LHV gas. Platinum and surprisingly the garnet were least deactivated. Palladium was severely affected for methane combustion while the other washcoat materials were

  6. Selective Catalytic Reduction of NO with Methane

    Institute of Scientific and Technical Information of China (English)

    Xiang Gao; Qi Yu; Limin Chen

    2003-01-01

    The removal of nitrogen oxides from exhaust gases has attracted great attention in recent years, and many approaches have been developed depending on the application. Methane, the main component of natural gas, has great potential as a NO reductant. In this paper, a number of catalysts previous reported for this catalytic reduction of NO have been reviewed, including a direct comparison of the relative activities and effective factors of the catalysts. Reaction mechanisms have also been explored preliminarily.

  7. Zeolitic catalytic conversion of alochols to hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

    2017-01-03

    A method for converting an alcohol to a hydrocarbon, the method comprising contacting said alcohol with a metal-loaded zeolite catalyst at a temperature of at least 100.degree. C. and up to 550.degree. C., wherein said alcohol can be produced by a fermentation process, said metal is a positively-charged metal ion, and said metal-loaded zeolite catalyst is catalytically active for converting said alcohol to said hydrocarbon.

  8. Catalytic fast pyrolysis of lignocellulosic biomass

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Changjun; Wang, Huamin; Karim, Ayman M.; Sun, Junming; Wang, Yong

    2014-11-21

    Increasing energy demand, especially in the transportation sector, and soaring CO2 emissions necessitate the exploitation of renewable sources of energy. Despite the large variety of new energy Q3 carriers, liquid hydrocarbon still appears to be the most attractive and feasible form of transportation fuel taking into account the energy density, stability and existing infrastructure. Biomass is an abundant, renewable source of energy; however, utilizing it in a cost-effective way is still a substantial challenge. Lignocellulose is composed of three major biopolymers, namely cellulose, hemicellulose and lignin. Fast pyrolysis of biomass is recognized as an efficient and feasible process to selectively convert lignocellulose into a liquid fuel—bio-oil. However bio-oil from fast pyrolysis contains a large amount of oxygen, distributed in hundreds of oxygenates. These oxygenates are the cause of many negative properties, such as low heating values, high corrosiveness, high viscosity, and instability; they also greatly Q4 limit the application of bio-oil particularly as transportation fuel. Hydrocarbons derived from biomass are most attractive because of their high energy density and compatibility with the existing infrastructure. Thus, converting lignocellulose into transportation fuels via catalytic fast pyrolysis has attracted much attention. Many studies related to catalytic fast pyrolysis of biomass have been published. The main challenge of this process is the development of active and stable catalysts that can deal with a large variety of decomposition intermediates from lignocellulose. This review starts with the current understanding of the chemistry in fast pyrolysis of lignocellulose and focuses on the development of catalysts in catalytic fast pyrolysis. Recent progress in the experimental studies on catalytic fast pyrolysis of biomass is also summarized with the emphasis on bio-oil yields and quality.

  9. Thermal and catalytic pyrolysis of plastic waste

    OpenAIRE

    Débora Almeida; Maria de Fátima Marques

    2016-01-01

    Abstract The amount of plastic waste is growing every year and with that comes an environmental concern regarding this problem. Pyrolysis as a tertiary recycling process is presented as a solution. Pyrolysis can be thermal or catalytical and can be performed under different experimental conditions. These conditions affect the type and amount of product obtained. With the pyrolysis process, products can be obtained with high added value, such as fuel oils and feedstock for new products. Zeolit...

  10. Studies of catalytic coal gasification with steam

    Directory of Open Access Journals (Sweden)

    Porada Stanisław

    2016-09-01

    Full Text Available One of the promising processes, belonging to the so-called clean coal technologies, is catalytic coal gasification. The addition of a catalyst results in an increased process rate, in which synthesis gas is obtained. Therefore, the subject of this research was catalytic gasification of low-ranking coal which, due to a high reactivity, meets the requirements for fuels used in the gasification process. Potassium and calcium cations in an amount of 0.85, 1.7 and 3.4% by weight were used as catalytically active substances. Isothermal measurements were performed at 900°C under a pressure of 2 MPa using steam as a gasifying agent. On the basis of kinetic curves, the performance of main gasification products as well as carbon conversion degree were determined. The performed measurements allowed the determination of the type and amount of catalyst that ensure the most efficient gasification process of the coal ‘Piast’ in an atmosphere of steam.

  11. A revolution in micropower : the catalytic nanodiode.

    Energy Technology Data Exchange (ETDEWEB)

    Cross, Karen Charlene; Heller, Edwin J.; Figiel, Jeffrey James; Coker, Eric Nicholas; Creighton, James Randall; Koleske, Daniel David; Bogart, Katherine Huderle Andersen; Coltrin, Michael Elliott; Pawlowski, Roger Patrick; Baucom, Kevin C.

    2010-11-01

    Our ability to field useful, nano-enabled microsystems that capitalize on recent advances in sensor technology is severely limited by the energy density of available power sources. The catalytic nanodiode (reported by Somorjai's group at Berkeley in 2005) was potentially an alternative revolutionary source of micropower. Their first reports claimed that a sizable fraction of the chemical energy may be harvested via hot electrons (a 'chemicurrent') that are created by the catalytic chemical reaction. We fabricated and tested Pt/GaN nanodiodes, which eventually produced currents up to several microamps. Our best reaction yields (electrons/CO{sub 2}) were on the order of 10{sup -3}; well below the 75% values first reported by Somorjai (we note they have also been unable to reproduce their early results). Over the course of this Project we have determined that the whole concept of 'chemicurrent', in fact, may be an illusion. Our results conclusively demonstrate that the current measured from our nanodiodes is derived from a thermoelectric voltage; we have found no credible evidence for true chemicurrent. Unfortunately this means that the catalytic nanodiode has no future as a micropower source.

  12. Water Filtration Products

    Science.gov (United States)

    1986-01-01

    American Water Corporation manufactures water filtration products which incorporate technology originally developed for manned space operations. The formula involves granular activated charcoal and other ingredients, and removes substances by catalytic reactions, mechanical filtration, and absorption. Details are proprietary. A NASA literature search contributed to development of the compound. The technology is being extended to a deodorizing compound called Biofresh which traps gas and moisture inside the unit. Further applications are anticipated.

  13. Magnetic carbon xerogels for the catalytic wet peroxide oxidation of 4-nitrophenol solutions

    OpenAIRE

    Ribeiro, R.; Silva, Adrián; Faria, Joaquim; Gomes, Helder

    2015-01-01

    Catalytic wet peroxide oxidation (CWPO) is a well-known advanced oxidation process for the removal of organic pollutants from industrial process waters and wastewater. Specifically, CWPO employs hydrogen peroxide (H2O2) as oxidation source and a suitable catalyst to promote its decomposition via formation of hydroxyl radicals (HO•), which exhibit high oxidizing potential and serve as effective species in the destruction of a huge range of organic pollutants

  14. Influence of real-world environments on the motion of catalytic bubble-propelled micromotors.

    Science.gov (United States)

    Zhao, Guanjia; Wang, Hong; Khezri, Bahareh; Webster, Richard D; Pumera, Martin

    2013-08-01

    Self-propelled autonomous micromachines have recently been tasked to carry out various roles in real environments. In this study, we expose the microjets to various types of water that are present in the real world, examples include tap water, rain water, lake water and sea water, and we sought to investigate their behaviors under real world conditions. We observed that the viability and mobility of the catalytic bubble jet engines are strongly influenced by the type of environmental water sample. Amongst the four water samples tested, the seawater sample exhibits the strongest influence, completely disabling any motions arising from the microjets. The motion of the microjets is also reduced in tap water, which contains large quantities of inorganic ions that have been purposely introduced into tap water via processing in water treatment plants. Lake water and rain water samples exhibited the least influence on the microjet's motion. All of the four water samples were also characterized by determining their ion compositions and conductivities, and we will show that there is a distinct correlation between the reduced mobility of the microjets with the ion content of the water found in real environments.

  15. Clinical analysis of anticoagulation for acute exacerbation of chronic obstructive pulmonary disease with co-existing suspected acute pulmonary embolism%慢性阻塞性肺疾病急性加重疑诊合并肺栓塞的抗凝治疗临床分析

    Institute of Scientific and Technical Information of China (English)

    张琪琳; 虞仲英; 张舒; 肖中; 蔡峰

    2008-01-01

    Objective To investigate the efficacy and safety of the anticoagulation for acute exacerbation of chronic obstructive pulmonary disease(AECOPD)with co-existing suspected acute pulmonary embolistn(PE).Methods Thirty-seven severe AECOPD inpatients with a positive D-dimer assay were divided into A group(a value of PaO2 was normal)and B group(hypoxia).The two groups were randomlv redistributed into anticoagulation subgroups(A1 and B1)and non-anticoagulation subgroups(A2 and B2).The consequences of the management were surveyed and assessed.Results Bi subgroup versus B2 subgrouP:there were significant differences in dyspnea,PaO2,D-dimer and ventilating time(P0.05).B1 subgroup was preferable to B2 subgroup.Conclusions Anticoagulation should immediately be given to patients with severe AECOPD who do not require further investigation of CTPA or isotope lung scanning for confirming PE,providing the patients have risk factors for venous thromboembolism or high probability for PE,and a positive D-dimer test,and receiving mechanic ventilation,and existing hypoxia,even SO be given oxygen or received non-invasive mechanic ventilation,and acute left heart failure and pneumothorax were excluded.%目的 探讨对重度慢性阻塞性肺疾病急性加重(acute exacerbation of chronic obstructive pulmonary disease,AECOPD)疑诊合并肺栓塞(PE)患者进行抗凝治疗的有效性和安全性.方法 将D-二聚体阳性的37例重度AECOPD患者分为血氧分压正常组(A组)和血氧分压降低组(B组),并对两组患者进一步随机分为抗凝(A1、B1)和非抗凝(A2、B2)两个亚组.分别观察和评估A组和B组抗凝和非抗凝治疗的临床变化.结果 B1,组和B2组比较:临床症状改善、动脉血气分析、D-二体和机械通气时间等比较差异有统计学意义(P<0.05),两组并发症比较差异无统计学意义(P>0.05),B1组优于B2组·结论具有静脉血栓栓塞高危因素或临床高度可疑PE、D-二体检测阳性的重度AECOPD机

  16. Effect of the Addition of CeO2 to Iron Phosphate Glass for Catalytic Applications.

    Science.gov (United States)

    Chung, Jae-Yeop; Kim, Jong-Hwan; Choi, Su-Yeon; Ryu, Bong-Ki

    2015-10-01

    We investigated the effect of CeO2 content on the catalytic behavior and chemical properties of the (100 - x)(80P2O5-20Fe2O3)-xCeO2 (x = 0, 4, 8, 12, 16, 20 and 24 wt%) glass system. Using thermogravimetric analysis, we confirmed that the catalytic activity increased until a CeO2 content of 16 wt%, beyond which, it decreased. The reasons for the change in the catalytic properties of the glass samples were determined using Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and density analyses. It was confirmed using the FT-IR and XPS-01s spectra that CeO2 acts as a network modifier in iron phosphate glass. When the CeO2 content is above 16 wt%, the number of non-bridging oxygen atoms decreases with increasing CeO2 content. For these reasons, the catalytic properties decrease when the CeO2 content is more than 16 wt%. From the dissolution rate measurements, it can be observed that cerium-iron phosphate has a high water resistance. Also, as we expected, it can be confirmed that the chemical durability is improved with increasing CeO2 content.

  17. Catalytic Combustion of Ethyl Acetate over Nanostructure Cobalt Supported ZSM-5 Zeolite Catalysts

    Institute of Scientific and Technical Information of China (English)

    NIAEI,Aligholi; SALARI,Dariush; HOSSEINI,Seyed Ali; KHATAMIAN,Masumeh; JODAEL,Azadeh

    2009-01-01

    Gas phase catalytic combustion of ethyl acetate,as one of volatile organic compounds(VOC),was studied on nanostructure ZSM-5.HZSM-5 and Co-ZSM-5 with different cobalt loadings. Nanostructure of ZSM-5 Was deter-mined by XRD,SEM and TEM. Catalytic studies were carried out under atmospheric pressure in a fixed bed reactor.Results showed that the Co-ZSM-5 catalysts had better activity than others and at temperatures below 350℃.amount of Co loading was mole effective on catalytic activity.The order of conversion of ethyl acetate over differ-ent Co loading is as follows:Co-ZSM-5(0.75 wt%)catalytic oxidation conditions has not so large influence on conversion. Furthermore,the presence of water vapor in inlet gaseous feed has an inhibitive effect on ethyl acetate conversion and at the temperatures above 400℃,the effect decreases.

  18. Surface Structure and Catalytic Performance of Ni-Fe Catalyst for Low-Temperature CO Hydrogenation

    Directory of Open Access Journals (Sweden)

    Fanhui Meng

    2014-01-01

    Full Text Available Catalysts 16NixFe/Al2O3 (x is 0, 1, 2, 4, 6, 8 were prepared by incipient wetness impregnation method and the catalytic performance for the production of synthetic natural gas (SNG from CO hydrogenation in slurry-bed reactor were studied. The catalysts were characterized by BET, XRD, UV-Vis DRS, H2-TPR, CO-TPD, and XPS, and the results showed that the introduction of iron improved the dispersion of Ni species, weakened the interaction between Ni species and support and decreased the reduction temperature and that catalyst formed Ni-Fe alloy when the content of iron exceeded 2%. Experimental results revealed that the addition of iron to the catalyst can effectively improve the catalytic performance of low-temperature CO methanation. Catalyst 16Ni4Fe/Al2O3 with the iron content of 4% exhibited the best catalytic performance, the conversion of CO and the yield of CH4 reached 97.2% and 84.9%, respectively, and the high catalytic performance of Ni-Fe catalyst was related to the property of formed Ni-Fe alloy. Further increase of iron content led to enhancing the water gas shift reaction.

  19. Substrate binding and catalytic mechanism in phospholipase C from Bacillus cereus. a molecular mechanics and molecular dynamics study

    DEFF Research Database (Denmark)

    da Graça Thrige, D; Buur, J R; Jørgensen, Flemming Steen

    1997-01-01

    For the first time a consistent catalytic mechanism of phospholipase C from Bacillus cereus is reported based on molecular mechanics calculations. We have identified the position of the nucleophilic water molecule, which is directly involved in the hydrolysis of the natural substrate phosphatidyl...

  20. The tritium labeling of Butibufen by heterogeneous catalytic exchange; Marcado del Butibufen con Tritio por inter- cambio catalitico en disolucion

    Energy Technology Data Exchange (ETDEWEB)

    Santamaria, J.; Rebollo, D.

    1986-07-01

    The labeling of a new non-steroidal antiinflammatory agent, Butibufen (2-(4-isobutylphenyl) butyric acid) was studied. The method used was heterogeneous catalytic exchange between Butibufen and tritiated water, obtained in situ. Purification was accomplished through thin layer chromatography. Concentration, purity and specific activity of the labeled drug were determined by ultraviolet and liquid scintillation techniques. (Author) 7 refs.

  1. Session 4: Catalytic behavior of Ni(II)-Al hydrotalcite like compounds in bio-ethanol steam reforming

    Energy Technology Data Exchange (ETDEWEB)

    Comas, J.; Laborde, M.; Amadeo, N. [Laboratorio de Procesos Cataliticos, Dpto. Ingenieria Quimica, Facultad de Ingenieria. Pabellon de Industrias. Ciudad Universitaria (1428) Buenos Aires (Argentina)

    2004-07-01

    In this work, the ethanol steam reforming on massive Ni(II)-Al hydrotalcite like compounds as catalyst, at 773 K and atmospheric pressure, was studied. In particular, from the experiments carried out at different water/ethanol feed ratio is possible to elucidate the catalytic behavior for ethanol steam reforming over Ni(II)-Al hydrotalcite. (authors)

  2. Heterogeneous catalytic materials solid state chemistry, surface chemistry and catalytic behaviour

    CERN Document Server

    Busca, Guido

    2014-01-01

    Heterogeneous Catalytic Materials discusses experimental methods and the latest developments in three areas of research: heterogeneous catalysis; surface chemistry; and the chemistry of catalysts. Catalytic materials are those solids that allow the chemical reaction to occur efficiently and cost-effectively. This book provides you with all necessary information to synthesize, characterize, and relate the properties of a catalyst to its behavior, enabling you to select the appropriate catalyst for the process and reactor system. Oxides (used both as catalysts and as supports for cata

  3. Catalytic gasification of bagasse for the production of methanol

    Energy Technology Data Exchange (ETDEWEB)

    Baker, E.G.; Brown, M.D.; Robertus, R.J.

    1985-10-01

    The purpose of the study was to evaluate the technical and economic feasibility of catalytic gasification of bagasse to produce methanol. In previous studies, a catalytic steam gasification process was developed which converted wood to methanol synthesis gas in one step using nickel based catalysts in a fluid-bed gasifier. Tests in a nominal 1 ton/day process development unit (PDU) gasifier with these same catalysts showed bagasse to be a good feedstock for fluid-bed gasifiers, but the catalysts deactivated quite rapidly in the presence of bagasse. Laboratory catalyst screening tests showed K/sub 2/CO/sub 3/ doped on the bagasse to be a promising catalyst for converting bagasse to methanol synthesis gas. PDU tests with 10 wt % K/sub 2/CO/sub 3/ doped on bagasse showed the technical feasibility of this type of catalyst on a larger scale. A high quality synthesis gas was produced and carbon conversion to gas was high. The gasifier was successfully operated without forming agglomerates of catalyst, ash, and char in the gasifier. There was no loss of activity throughout the runs because catalysts is continually added with the bagasse. Laboratory tests showed about 80% of the potassium carbonate could be recovered and recycled with a simple water wash. An economic evaluation of the process for converting bagasse to methanol showed the required selling price of methanol to be significantly higher than the current market price of methanol. Several factors make this current evaluaton using bagasse as a feedstock less favorable: (1) capital costs are higher due to inflation and some extra costs required to use bagasse, (2) smaller plant sizes were considered so economies of scale are lost, and (3) the market price of methanol in the US has fallen 44% in the last six months. 24 refs., 14 figs., 16 tabs.

  4. Catalytic bioscavengers in nerve agent poisoning: A promising approach?

    Science.gov (United States)

    Worek, Franz; Thiermann, Horst; Wille, Timo

    2016-02-26

    The repeated use of the nerve agent sarin against civilians in Syria in 2013 emphasizes the continuing threat by chemical warfare agents. Multiple studies demonstrated a limited efficacy of standard atropine-oxime treatment in nerve agent poisoning and called for the development of alternative and more effective treatment strategies. A novel approach is the use of stoichiometric or catalytic bioscavengers for detoxification of nerve agents in the systemic circulation prior to distribution into target tissues. Recent progress in the design of enzyme mutants with reversed stereo selectivity resulting in improved catalytic activity and their use in in vivo studies supports the concept of catalytic bioscavengers. Yet, further research is necessary to improve the catalytic activity, substrate spectrum and in vivo biological stability of enzyme mutants. The pros and cons of catalytic bioscavengers will be discussed in detail and future requirements for the development of catalytic bioscavengers will be proposed.

  5. Catalytic Synthesis Methods for Triazolopyrimidine Derivatives

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A new method for catalyzed synthesis of triazolopyrimidine derivatives is reported. Aikylamine reaction with dialkyl cyanodithioiminocarbonate was catalyzed by quaternary ammonium salts at room temperature to yield 3-alkylamine-5-amino-1,2,4-triazole in good quality and high yields. After imidization and reaction with an α,β-unsaturated acid derivative, the reaction intermediate was hydrolyzed in the presence of a Lewis acid to obtain the target product. This novel catalytic method for triazolopyrimidine derivatives can be carried out under inexpen-sive and mild conditions, and is safe and environmentally friendly. IH NMR results for all intermediates are re-ported.

  6. Thin film porous membranes for catalytic sensors

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.C.; Boyle, T.J.; Gardner, T.J. [and others

    1997-06-01

    This paper reports on new and surprising experimental data for catalytic film gas sensing resistors coated with nanoporous sol-gel films to impart selectivity and durability to the sensor structure. This work is the result of attempts to build selectivity and reactivity to the surface of a sensor by modifying it with a series of sol-gel layers. The initial sol-gel SiO{sub 2} layer applied to the sensor surprisingly showed enhanced O{sub 2} interaction with H{sub 2} and reduced susceptibility to poisons such as H{sub 2}S.

  7. Catalytic Synthesis of Nitriles in Continuous Flow

    DEFF Research Database (Denmark)

    Nordvang, Emily Catherine

    , alternative path to acetonitrile from ethanol via the oxidative dehydrogenation of ethylamine. The catalytic activity and product ratios of the batch and continuous flow reactions are compared and the effect of reaction conditions on the reaction is investigated. The effects of ammonia in the reaction...... dehydrogenation of ethylamine and post-reaction purging.Chapter 4 outlines the application of RuO2/Al2O3 catalysts to the oxidative dehydrogenation of benzylamine in air, utilizing a new reaction setup. Again, batch and continuous flow reactions are compared and the effects of reaction conditions, ammonia...

  8. Biomimetic, Catalytic Oxidation in Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    Shun-lchi Murahashi

    2005-01-01

    @@ 1Introduction Oxidation is one of the most fundamental reactions in organic synthesis. Owing to the current need to develop forward-looking technology that is environmentally acceptable with respect many aspects. The most attractive approaches are biomimetic oxidation reactions that are closely related to the metabolism of living things. The metabolisms are governed by a variety of enzymes such as cytochrome P-450 and flavoenzyme.Simulation of the function of these enzymes with simple transition metal complex catalyst or organic catalysts led to the discovery of biomimetic, catalytic oxidations with peroxides[1]. We extended such biomimetic methods to the oxidation with molecular oxygen under mild conditions.

  9. Catalytic wet oxidation of black liquor

    OpenAIRE

    Viader Riera, Gerard

    2012-01-01

    The major aspects of wet air oxidation and catalytic wet air oxidation have been reviewed in this work paying special attention to the reaction mechanisms, kinetics and the industrial process. In the experimental section a set of heterogeneous catalysts have been tested in the wet oxidation of non-wood black liquor. The oxidation runs were performed batchwise in a laboratory-scale mechanically stirred slurry reactor for 1 h at a temperature of 170°C and total pressure of 12 bar. Pure oxygen w...

  10. Catalytic enantioselective synthesis of quaternary carbon stereocentres

    Science.gov (United States)

    Quasdorf, Kyle W.; Overman, Larry E.

    2014-12-01

    Quaternary carbon stereocentres--carbon atoms to which four distinct carbon substituents are attached--are common features of molecules found in nature. However, before recent advances in chemical catalysis, there were few methods of constructing single stereoisomers of this important structural motif. Here we discuss the many catalytic enantioselective reactions developed during the past decade for the synthesis of single stereoisomers of such organic molecules. This progress now makes it possible to incorporate quaternary stereocentres selectively in many organic molecules that are useful in medicine, agriculture and potentially other areas such as flavouring, fragrances and materials.

  11. Remediation of actual groundwater polluted with nitrate by the catalytic reduction over copper-palladium supported on active carbon

    OpenAIRE

    Wang, Yi; Sakamoto, Yoshinori; Kamiya, Yuichi

    2009-01-01

    Catalytic reduction of nitrate (NO3-) in groundwater over a Cu-Pd catalyst supported on active carbon was investigated in a gas-liquid co-current flow system at 298 K. Although Cu-Pd/active carbon, in which the Cu/Pd molar ratio was more than 0.66, showed high activity, high selectivity for the formation of N2 and N2O (98%), and high durability for the reduction of 100 ppm NO3- in distilled water, the catalytic performance decreased during the reduction of NO3- in groundwater. The catalyst al...

  12. Destruction of organochlorated compounds and CFCs by catalytic hydrodechloration; Destruccion de compuestos organoclorados y CFCs mediante hidrodecloracion catalitica

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez Garcia, S.; Sastre Andres, H.; Diez Sanz, F. V.

    1998-12-01

    The destruction of organohalogenated compounds ( for example chlorinated solvents, PCBs and CFCs) is a very serious environmental problems. Catalytic hydrodechlorination has shown to be potentially efficient method for the destruction of these compounds. In this technique the halogenated compound reacts with hydrogen, tielding a non-chlorinated compound (environmentally harmless) and hydrogen-chloride. In this article, different set-ups and catalysts employed in the catalytic hydrogechlorination were described. Finally, some applications of this technique to the treatment of industrial effluents, such as the destruction of chlorinated solvents (as trichloroethylene o tetrachloromethane), conversion of CFCs into HCFCs, destruction of PCBs and treatment of water polluted with chlorinated pesticides. (Author) 28 refs.

  13. Including lateral interactions into microkinetic models of catalytic reactions

    DEFF Research Database (Denmark)

    Hellman, Anders; Honkala, Johanna Karoliina

    2007-01-01

    In many catalytic reactions lateral interactions between adsorbates are believed to have a strong influence on the reaction rates. We apply a microkinetic model to explore the effect of lateral interactions and how to efficiently take them into account in a simple catalytic reaction. Three differ...... different approximations are investigated: site, mean-field, and quasichemical approximations. The obtained results are compared to accurate Monte Carlo numbers. In the end, we apply the approximations to a real catalytic reaction, namely, ammonia synthesis....

  14. Study and Analysis on Naphtha Catalytic Reforming Reactor Simulation

    Institute of Scientific and Technical Information of China (English)

    Liang Ke min; Song Yongji; Pan Shiwei

    2004-01-01

    A naphtha catalytic reforming unit with four reactors connected in series is analyzed. A physical model is proposed to describe the catalytic reforming radial flow reactor. Kinetics and thermodynamics equations are selected to describe the naphtha catalytic reforming reaction characteristics based on idealizing the complex naphtha mixture to represent the paraffin, naphthene, and aromatic groups with individual compounds. The simulation results based on above models agree very well with actual operating data of process unit.

  15. A study on naphtha catalytic reforming reactor simulation and analysis

    Institute of Scientific and Technical Information of China (English)

    LIANG Ke-min; GUO Hai-yan; PAN Shi-wei

    2005-01-01

    A naphtha catalytic reforming unit with four reactors in series is analyzed. A physical model is proposed to describe the catalytic reforming radial flow reactor. Kinetics and thermodynamics equations are selected to describe the naphtha catalytic reforming reactions characteristics based on idealizing the complex naphtha mixture by representing the paraffin, naphthene, and aromatic groups by single compounds. The simulation results based above models agree very well with actual operation unit data.

  16. Side reactions in the selective catalytic reduction of NO with NH{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Madia, G.; Koebel, M.; Elsener, M.; Wokaun, A.

    2002-03-01

    The main and the side reactions of the SCR reaction with ammonia over TiO{sub 2}-WO{sub 3}-V{sub 2}O{sub 5} catalysts have been investigated using synthetic gas mixtures matching the composition of diesel exhaust. At high temperatures the selective catalytic oxidation of ammonia (SCO) and the formation of nitrous oxide compete with the SCR reaction. Water strongly inhibits the SCO of ammonia and the formation of nitrous oxide thus increasing the selectivity of the SCR reaction. However, water also inhibits SCR activity, most pronounced at low temperatures. (author)

  17. Catalytically favorable surface patterns in Pt-Au nanoclusters

    KAUST Repository

    Mokkath, Junais Habeeb

    2013-01-01

    Motivated by recent experimental demonstrations of novel PtAu nanoparticles with highly enhanced catalytic properties, we present a systematic theoretical study that explores principal catalytic indicators as a function of the particle size and composition. We find that Pt electronic states in the vicinity of the Fermi level combined with a modified electron distribution in the nanoparticle due to Pt-to-Au charge transfer are the origin of the outstanding catalytic properties. From our model we deduce the catalytically favorable surface patterns that induce ensemble and ligand effects. © The Royal Society of Chemistry 2013.

  18. The Three-Dimensional Structure and Catalytic Mechanism of Cytosine Deaminase†

    Science.gov (United States)

    Hall, Richard S.; Fedorov, Alexander A.; Xu, Chengfu; Fedorov, Elena V.; Almo, Steven C.; Raushel, Frank M.

    2011-01-01

    Cytosine deaminase (CDA) from E. coli is a member of the amidohydrolase superfamily. The structure of the zinc-activated enzyme was determined in the presence of phosphonocytosine, a mimic of the tetrahedral reaction intermediate. This compound inhibits the deamination of cytosine with a Ki of 52 nM. The zinc and iron containing enzymes were characterized to determine the effect of the divalent cations on activation of the hydrolytic water. Fe-CDA loses activity at low pH with a kinetic pKa of 6.0 and Zn-CDA has a kinetic pKa of 7.3. Mutation of Gln-156 decreased the catalytic activity by more than 5 orders of magnitude, supporting its role in substrate binding. Mutation of Glu-217, Asp-313, and His-246 significantly decreased catalytic activity supporting the role of these three residues in activation of the hydrolytic water molecule and facilitation of proton transfer reactions. A library of potential substrates was used to probe the structural determinants responsible for catalytic activity. CDA was able to catalyze the deamination of isocytosine and the hydrolysis of 3-oxauracil. Large inverse solvent isotope effects were obtained on kcat and kcat/Km, consistent with the formation of a low-barrier hydrogen bond during the conversion of cytosine to uracil. A chemical mechanism for substrate deamination by CDA was proposed. PMID:21545144

  19. Cations and hydration in catalytic RNA: molecular dynamics of the hepatitis delta virus ribozyme.

    Science.gov (United States)

    Krasovska, Maryna V; Sefcikova, Jana; Réblová, Kamila; Schneider, Bohdan; Walter, Nils G; Sponer, Jirí

    2006-07-15

    The hepatitis delta virus (HDV) ribozyme is an RNA enzyme from the human pathogenic HDV. Cations play a crucial role in self-cleavage of the HDV ribozyme, by promoting both folding and chemistry. Experimental studies have revealed limited but intriguing details on the location and structural and catalytic functions of metal ions. Here, we analyze a total of approximately 200 ns of explicit-solvent molecular dynamics simulations to provide a complementary atomistic view of the binding of monovalent and divalent cations as well as water molecules to reaction precursor and product forms of the HDV ribozyme. Our simulations find that an Mg2+ cation binds stably, by both inner- and outer-sphere contacts, to the electronegative catalytic pocket of the reaction precursor, in a position to potentially support chemistry. In contrast, protonation of the catalytically involved C75 in the precursor or artificial placement of this Mg2+ into the product structure result in its swift expulsion from the active site. These findings are consistent with a concerted reaction mechanism in which C75 and hydrated Mg2+ act as general base and acid, respectively. Monovalent cations bind to the active site and elsewhere assisted by structurally bridging long-residency water molecules, but are generally delocalized.

  20. Catalytic hydrothermal pretreatment of corncob into xylose and furfural via solid acid catalyst.

    Science.gov (United States)

    Li, Huiling; Deng, Aojie; Ren, Junli; Liu, Changyu; Lu, Qi; Zhong, Linjie; Peng, Feng; Sun, Runcang

    2014-04-01

    Selectively catalytic hydrothermal pretreatment of corncob into xylose and furfural has been developed in this work using solid acid catalyst (SO4(2-)/TiO2-ZrO2/La(3+)). The effects of corncob-to-water ratio, reaction temperature and residence time on the performance of catalytic hydrothermal pretreatment were investigated. Results showed that the solid residues contained mainly lignin and cellulose, which was indicative of the efficient removal of hemicelluloses from corncob by hydrothermal method. The prepared catalyst with high thermal stability and strong acid sites originated from the acid functional groups was confirmed to contribute to the hydrolysis of polysaccharides into monosaccharides followed by dehydration into furfural. Highest furfural yield (6.18 g/100g) could be obtained at 180°C for 120 min with 6.80 g/100g xylose yield when the corncob/water ratio of was 10:100. Therefore, selectively catalytic hydrothermal pretreatment of lignocellulosic biomass into important platform chemicals by solid acids is considered to be a potential treatment for biodiesel and chemical production.

  1. Catalytic Deoxydehydration of Carbohydrates and Polyols to Chemicals and Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas, Kenneth M. [Univ. of Oklahoma, Norman, OK (United States)

    2016-01-15

    As the world's fossil fuel resources are being depleted and their costs increase, there is an urgent need to discover and develop new processes for the conversion of renewable, biomass resources into fuels and chemical feedstocks. Research and development in this area have been given high priority by both governmental agencies and industry. To increase the energy content and decrease the boiling points of biomass-derived carbohydrates and polyols to the useful liquid range it is necessary to chemically remove water (dehydrate) and, preferably, oxygen (deoxygenate/reduce). The poly-hydroxylic nature of carbohydrates is attractive for their use as functionalized chemical building blocks, but it presents a daunting challenge for their selective conversion to single product chemicals or fuels. The long term, practical objective of this project is to develop catalytic processes for the deoxydehydration (DODH) of biomass-derived carbohydrates and polyols to produce unsaturated alcohols and hydrocarbons of value as chemical feedstocks and fuels; DODH: polyol + reductant --(LMOx catalyst)--> unsaturate + oxidized reductant + H2O. Limited prior studies have established the viability of the DODH process with expensive phosphine reductants and rhenium-catalysts. Initial studies in the PI's laboratory have now demonstrated: 1) the moderately efficient conversion of glycols to olefins by the economical sulfite salts is catalyzed by MeReO3 and Z+ReO4-; 2) effective phosphine-based catalytic DODH of representative glycols to olefins by cheap LMoO2 complexes; and 3) computational studies (with K. Houk, UCLA) have identified several Mo-, W-, and V-oxo complexes that are likely to catalyze glycol DODH. Seeking practically useful DODH reactions of complex polyols and new understanding of the reactivity of polyoxo-metal species with biomass-oxygenates we will employ a two-pronged approach: 1) investigate experimentally the reactivity, both stoichiometric and catalytic, of

  2. Electrochemical promotion of sulfur dioxide catalytic oxidation

    DEFF Research Database (Denmark)

    Petrushina, Irina; Bandur, Viktor; Cappeln, Frederik Vilhelm

    2000-01-01

    The effect of electrochemical polarization on the catalytic SO2 oxidation in the molten V2O5-K2S2O7 system has been studied using a gold working electrode in the temperature range 400-460 degrees C. A similar experiment has been performed with the industrial catalyst VK-58. The aim of the present...... investigation was to study a possible non-Faradaic electrochemical promotion of the liquid-phase catalytic reaction. It has been shown that there are two negative potential promotion areas with maximum effects at approximately -0.1 and -0.2 V, and one positive potential promotion area with the maximum effect...... caused by the negative charge on the electrode. The Faradaic part of the promoting effect under positive polarization has been explained as the electrochemical pushing of the V(V) V(IV) equilibrium in the direction of V(V) formation. It has also been shown that when using the industrial VK-58 catalyst...

  3. Cutoff lensing: predicting catalytic sites in enzymes

    Science.gov (United States)

    Aubailly, Simon; Piazza, Francesco

    2015-10-01

    Predicting function-related amino acids in proteins with unknown function or unknown allosteric binding sites in drug-targeted proteins is a task of paramount importance in molecular biomedicine. In this paper we introduce a simple, light and computationally inexpensive structure-based method to identify catalytic sites in enzymes. Our method, termed cutoff lensing, is a general procedure consisting in letting the cutoff used to build an elastic network model increase to large values. A validation of our method against a large database of annotated enzymes shows that optimal values of the cutoff exist such that three different structure-based indicators allow one to recover a maximum of the known catalytic sites. Interestingly, we find that the larger the structures the greater the predictive power afforded by our method. Possible ways to combine the three indicators into a single figure of merit and into a specific sequential analysis are suggested and discussed with reference to the classic case of HIV-protease. Our method could be used as a complement to other sequence- and/or structure-based methods to narrow the results of large-scale screenings.

  4. Computational and Physical Analysis of Catalytic Compounds

    Science.gov (United States)

    Wu, Richard; Sohn, Jung Jae; Kyung, Richard

    2015-03-01

    Nanoparticles exhibit unique physical and chemical properties depending on their geometrical properties. For this reason, synthesis of nanoparticles with controlled shape and size is important to use their unique properties. Catalyst supports are usually made of high-surface-area porous oxides or carbon nanomaterials. These support materials stabilize metal catalysts against sintering at high reaction temperatures. Many studies have demonstrated large enhancements of catalytic behavior due to the role of the oxide-metal interface. In this paper, the catalyzing ability of supported nano metal oxides, such as silicon oxide and titanium oxide compounds as catalysts have been analyzed using computational chemistry method. Computational programs such as Gamess and Chemcraft has been used in an effort to compute the efficiencies of catalytic compounds, and bonding energy changes during the optimization convergence. The result illustrates how the metal oxides stabilize and the steps that it takes. The graph of the energy computation step(N) versus energy(kcal/mol) curve shows that the energy of the titania converges faster at the 7th iteration calculation, whereas the silica converges at the 9th iteration calculation.

  5. Structured materials for catalytic and sensing applications

    Science.gov (United States)

    Hokenek, Selma

    The optical and chemical properties of the materials used in catalytic and sensing applications directly determine the characteristics of the resultant catalyst or sensor. It is well known that a catalyst needs to have high activity, selectivity, and stability to be viable in an industrial setting. The hydrogenation activity of palladium catalysts is known to be excellent, but the industrial applications are limited by the cost of obtaining catalyst in amounts large enough to make their use economical. As a result, alloying palladium with a cheaper, more widely available metal while maintaining the high catalytic activity seen in monometallic catalysts is, therefore, an attractive option. Similarly, the optical properties of nanoscale materials used for sensing must be attuned to their application. By adjusting the shape and composition of nanoparticles used in such applications, very fine changes can be made to the frequency of light that they absorb most efficiently. The design, synthesis, and characterization of (i) size controlled monometallic palladium nanoparticles for catalytic applications, (ii) nickel-palladium bimetallic nanoparticles and (iii) silver-palladium nanoparticles with applications in drug detection and biosensing through surface plasmon resonance, respectively, will be discussed. The composition, size, and shape of the nanoparticles formed were controlled through the use of wet chemistry techniques. After synthesis, the nanoparticles were analyzed using physical and chemical characterization techniques such as X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Scanning Transmission Electron Microscopy- Energy-Dispersive Spectrometry (STEM-EDX). The Pd and Ni-Pd nanoparticles were then supported on silica for catalytic testing using mass spectrometry. The optical properties of the Ag-Pd nanoparticles in suspension were further investigated using ultraviolet-visible spectrometry (UV-Vis). Monometallic palladium particles have

  6. Correlation between the Structure and Catalytic Activity of [Cp*Rh(Substituted Bipyridine)] Complexes for NADH Regeneration.

    Science.gov (United States)

    Ganesan, Vinothkumar; Sivanesan, Dharmalingam; Yoon, Sungho

    2017-02-06

    A series of water-soluble half-sandwich [Cp*Rh(III)(N^N)Cl](+) (Cp* = pentamethylcyclopentadiene, N^N-substituted 2,2'-bipyridine) complexes containing electron-donating substituents around the 2,2'-bipyridyl ligand were synthesized and fully characterized for the regioselective reduction of nicotinamide coenzyme (NAD(+)). The influence of the positional effect of the substituents on the structural, electrochemical, and catalytic properties of the catalyst was systematically studied in detail. The catalytic efficiency of the substituted bipyridine Cp*Rh(III) complexes are inversely correlated with their redox potentials. The 5,5'-substituted bipyridine Cp*Rh(III) complex, which had the lowest reduction potential, most effectively regenerated NADH with a turnover frequency of 1100 h(-1). Detailed kinetic studies on the generation of intermediate(s) provide valuable mechanistic insight into this catalytic cycle and help to direct the future design strategy of corresponding catalysts.

  7. The effect of microwave-assisted for photo-catalytic reaction in aqueous nano TiO2 particles dispersions.

    Science.gov (United States)

    Chae, Jeong-Seok; Chung, Minchul; Ahn, Ho-Geun; Jung, Sang-Chul

    2010-05-01

    In this study, the photo-catalytic degradation of methylene blue in TiO2 particles-dispersed aqueous solution was carried out by irradiating microwave and UV light simultaneously. The results of photocatalytic degradation of methylene blue showed that the decomposition rate increased with the microwave intensity, UV intensity, TiO2 particle dosages and the circulating fluid velocity. From the result of microwave-assisted photo-catalytic degradation of methylene blue, decomposition rate were shown gradually increased according to the increase of pH. The photo-catalytic degradation rate constant obtained under simultaneous irradiation of microwave and UV light case was about 1.5 times higher than irradiation of UV light only case. This result suggests that there is a synergy effect when the constituent techniques are applied together and that the additional irradiation of microwave can play a very important role in photo-catalysis of organic water pollutants.

  8. Polarographic catalytic wave of hydrogen--Parallel catalytic hydrogen wave of bovine serum albumin in thepresence of oxidants

    Institute of Scientific and Technical Information of China (English)

    GUO; Wei(过玮); LIU; Limin(刘利民); LIN; Hong(林洪); SONG; Junfeng(宋俊峰)

    2002-01-01

    A polarographic catalytic hydrogen wave of bovine serum albumin (BSA) at about -1.80 V (vs. SCE) in NH4Cl-NH3@H2O buffer is further catalyzed by such oxidants as iodate, persulfate and hydrogen peroxide, producing a kinetic wave. Studies show that the kinetic wave is a parallel catalytic wave of hydrogen, which resulted from that hydrogen ion is electrochemically reduced and chemically regenerated through oxidation of its reduction product, atomic hydrogen, by oxidants mentioned above. It is a new type of poralographic catalytic wave of protein, which is suggested to be named as a parallel catalytic hydrogen wave.

  9. Cyclosophorohexadecaose and succinoglycan monomers as catalytic carbohydrates for the Strecker reaction.

    Science.gov (United States)

    Lee, Sanghoo; Cho, Eunae; Kwon, Chanho; Jung, Seunho

    2007-12-10

    Some microbial carbohydrates have been used as catalysts for the multicomponent Strecker reaction using trimethylsilyl cyanide (TMSCN). Alpha-Cyclosophorohexadecaose (alpha-C16) derived from Xanthomonas species and succinoglycan monomers derived from Rhizobium species acted as catalytic carbohydrates in the mixture solutions of methanol and water. Malonaldehyde bis(phenylimine) as a substrate was completely converted (yield: 100%) into its product to 100% by both alpha-C16 and the succinoglycan monomer (M2), having acetyl, pyruvyl, and succinyl groups as substituents after 1h. The catalytic abilities of the carbohydrates were dependent on the inherent structures of the substrates used in this study, where substrate 1 having a symmetrical structure rather than the others was favorably reacted with the alpha-C16 and M2. Through this study, we suggest that the microbial carbohydrates used in this study could be expected to be environmentally-benign catalysts for the synthesis of alpha-aminonitriles.

  10. Catalytic non-thermal plasma reactor for the decomposition of a mixture of volatile organic compounds

    Indian Academy of Sciences (India)

    B Rama Raju; E Linga Reddy; J Karuppiah; P Manoj Kumar Reddy; Ch Subrahmanyam

    2013-05-01

    The decomposition of mixture of selected volatile organic compounds (VOCs) has been studied in a catalytic non-thermal plasma dielectric barrier discharge reactor. The VOCs mixture consisting n-hexane, cyclo-hexane and -xylene was chosen for the present study. The decomposition characteristics of mixture of VOCs by the DBD reactor with inner electrode modified with metal oxides of Mn and Co was studied. The results indicated that the order of the removal efficiency of VOCs followed as -xylene > cyclo-hexane > -hexane. Among the catalytic study, MnOx/SMF (manganese oxide on sintered metal fibres electrode) shows better performance, probably due to the formation of active oxygen species by in situ decomposition of ozone on the catalyst surface. Water vapour further enhanced the performance due to the in situ formation of OH radicals.

  11. Catalytic oxidation for treatment of ECLSS and PMMS waste streams. [Process Material Management Systems

    Science.gov (United States)

    Akse, James R.; Thompson, John; Scott, Bryan; Jolly, Clifford; Carter, Donald L.

    1992-01-01

    Catalytic oxidation was added to the baseline multifiltration technology for use on the Space Station Freedom in order to convert low-molecular weight organic waste components such as alcohols, aldehydes, ketones, amides, and thiocarbamides to CO2 at low temperature (121 C), thereby reducing the total organic carbon (TOC) to below 500 ppb. The rate of reaction for the catalytic oxidation of aqueous organics to CO2 and water depends primarily upon the catalyst, temperature, and concentration of reactants. This paper describes a kinetic study conducted to determine the impact of each of these parameters upon the reaction rate. The results indicate that a classic kinetic model, the Langmuir-Hinshelwood rate equation for heterogeneous catalysis, can accurately represent the functional dependencies of this rate.

  12. Selective catalytic reduction of nitric oxide by ammonia over Cu-exchanged Cuban natural zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Tost, Ramon; Santamaria-Gonzalez, Jose; Rodriguez-Castellon, Enrique; Jimenez-Lopez, Antonio [Departamento de Quimica Inorganica, Cristalografia y Mineralogia, Facultad de Ciencias, Unidad Asociada del Instituto de Catalisis y Petroleoquimica, CSIC, Universidad de Malaga, Campus de Teatinos, 29071 Malaga (Spain); Autie, Miguel A.; Glacial, Marisol Carreras [Centro Nacional de Investigaciones Cientificas, Ciudad de la Habana, La Habana (Cuba); Gonzalez, Edel [Instituto Superior Pedagogico ' Enrique Jose Varona' , La Habana (Cuba); Pozas, Carlos De las [Centro de Gerencia de Programas y Proyectos Priorizados, La Habana (Cuba)

    2004-07-15

    The catalytic selective reduction of NO over Cu-exchanged natural zeolites (mordenite (MP) and clinoptilolite (HC)) from Cuba using NH{sub 3} as reducing agent and in the presence of excess oxygen was studied. Cu(II)-exchanged zeolites are very active catalysts, with conversions of NO of 95%, a high selectivity to N{sub 2} at low temperatures, and exhibiting good water tolerance. The chemical state of the Cu(II) in exchanged zeolites was characterized by H{sub 2}-TPR and XPS. Cu(II)-exchanged clinoptilolite underwent a severe deactivation in the presence of SO{sub 2}. However, Cu(II)-exchanged mordenite not only maintained its catalytic activity, but even showed a slight improvement after 20h of reaction in the presence of 100ppm of SO{sub 2}.

  13. Catalytic conversion of nonfood woody biomass solids to organic liquids.

    Science.gov (United States)

    Barta, Katalin; Ford, Peter C

    2014-05-20

    This Account outlines recent efforts in our laboratories addressing a fundamental challenge of sustainability chemistry, the effective utilization of biomass for production of chemicals and fuels. Efficient methods for converting renewable biomass solids to chemicals and liquid fuels would reduce society's dependence on nonrenewable petroleum resources while easing the atmospheric carbon dioxide burden. The major nonfood component of biomass is lignocellulose, a matrix of the biopolymers cellulose, hemicellulose, and lignin. New approaches are needed to effect facile conversion of lignocellulose solids to liquid fuels and to other chemical precursors without the formation of intractable side products and with sufficient specificity to give economically sustainable product streams. We have devised a novel catalytic system whereby the renewable feedstocks cellulose, organosolv lignin, and even lignocellulose composites such as sawdust are transformed into organic liquids. The reaction medium is supercritical methanol (sc-MeOH), while the catalyst is a copper-doped porous metal oxide (PMO) prepared from inexpensive, Earth-abundant starting materials. This transformation occurs in a single stage reactor operating at 300-320 °C and 160-220 bar. The reducing equivalents for these transformations are derived by the reforming of MeOH (to H2 and CO), which thereby serves as a "liquid syngas" in the present case. Water generated by deoxygenation processes is quickly removed by the water-gas shift reaction. The Cu-doped PMO serves multiple purposes, catalyzing substrate hydrogenolysis and hydrogenation as well as the methanol reforming and shift reactions. This one-pot "UCSB process" is quantitative, giving little or no biochar residual. Provided is an overview of these catalysis studies beginning with reactions of the model compound dihydrobenzofuran that help define the key processes occurring. The initial step is phenyl-ether bond hydrogenolysis, and this is followed by

  14. Study on Determination of Chemical Oxygen Demand in Water with Ion Chromatography

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhong-Hai; DING Hong-Chun; FANG Yan-Ju; XIAN Yue-Zhong; JIN Li-Tong

    2007-01-01

    A new method for determining chemical oxygen demand (COD) value in water using ion chromatography coupled with nano TiO2-K2S2O8 co-existing system was described. The photocatalytic oxidation system and nano TiO2-K2S2O8 co-existing system could degrade the organic compounds in water. All sulfur-containing species in the reactive solution were eventually transformed to sulfate which could be determined by conductivity detector in ion chromatography. The change of conductivity of sulfate was proportional to COD value. The optimal experimental conditions and the mechanism of the detection were discussed. The application range was 10.0-300.0 mg·L -1 and the lowest limit of detection was 3.5 mg·L -1. It was considered that the value obtained could be reliably correlated with the COD value obtained using the conventional methods.

  15. Evaluation of Performance Catalytic Ozonation Process with Activated Carbon in the Removal of Humic Acids from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Gh. Asgari

    2011-01-01

    Full Text Available Introduction & Objective: In recent years, the use of alternative disinfectants and the control of natural organic matters are two approaches that are typically applied in water treatment utilities to reduce the formation of chlorinated disinfection by-products. Catalytic ozonation is a new technology used to promote the efficiency of ozonation. The goal of this study was to survey the feasibility application of activated carbon as a catalyst in ozonation process for removal of humic acids from aqueous solution. Materials & Methods: This experimental study has been done in laboratory of water and wastewater chemistry, Tarbiat Modarres University. The solid structure and chemical composition of activated carbon were analyzed by X-ray fluorescence (XRF. Ozonation and catalytic ozonation experiments were performed in a semi-batch reactor and the mass of ozone produced was measured by iodometric titration methods. Concentration changes of humic acid in samples with a concentration of 15 mg/l were determined by using spectrophotometer at an absorbance wavelength of 254 nm. To evaluate the performance of catalytic ozonation in humic acid removal, total organic carbon and trihalomethane formation potential were evaluated and the results were analyzed by Excel software. Results: Catalytic ozone results showed that using activated carbon as a catalyst increased humic acid decomposition up to 11 times and removal efficiency increased with increasing pH (4-12 and catalyst dosage (0.25-1.5 g/250cc. The experimental results showed that catalytic ozonation was most effective in less time (10 min with considerable efficiency (95% compared to the sole ozonation process (SOP. Conclusion: The results indicated that the catalytic ozonation process, compared to SOP, was less affected by radical scavenger, and total organic carbon, and trihalomethane formation potential removal achieved were 30% and 83%, respectively. (Sci J Hamadan Univ Med Sci 2011;17(4:25-33

  16. [Catalytic Degradation of Diclofenac Sodium over the Catalyst of 3D Flower-like alpha-FeOOH Synergized with H2O2 Under Visible Light Irradiation].

    Science.gov (United States)

    Xu, Jun-ge; Li, Yun-qin; Huang, Hua-shan; Yuan, Bao-ling; Cui, Hao-jie; Fu, Ming-lai

    2015-06-01

    Three dimensional (3D) flower-like alpha-FeOOH nanomaterials were prepared by oil bath reflux method using FeSO4, urea, ethanol and water, and the products which were characterized by XRD, FT-IR and SEM techniques. The SEM images showed that the 3D flower-like samples consisted of nanorods with a length of 400-500 nm and a diameter of 40-60 nm. The catalytic performance of the samples was evaluated by catalytic degradation of diclofenac sodium using H2O2 as the oxidant under simulated visible light. The results showed that the as-prepared samples presented high efficient catalytic performances, and more than 99% of the initial diclofenac sodium (30 mg x L(-1)) was degraded in 90 min. A radical mechanism can be proposed for the catalytic degradation of diclofenac sodium solution.

  17. Catalytic synthesis of ammonia using vibrationally excited nitrogen molecules

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Henriksen, Niels Engholm; Billing, Gert D.

    1992-01-01

    The dissociation of nitrogen is the rate-limiting step in the catalytic synthesis of ammonia. Theoretical calculations have shown that the dissociative sticking probability of molecular nitrogen on catalytic active metal surfaces is enhanced by orders of magnitude when the molecules...

  18. Functionalized TUD-1: synthesis, characterization and (photo-)catalytic performance

    NARCIS (Netherlands)

    Hamdy M. Saad, M.S.

    2005-01-01

    The new mesoporous material; TUD-1 is chosen of which the synthesis, characterization, and functionalization for (photo)-catalytic performance are extensively investigated in this study. The synthesis of the new catalytic materials M TUD-1 (M = Ti, V, Cr, Mo, Fe, Co and Cu) is carried out through an

  19. Catalytic systems of cumene oxidation based on multiwalled carbon nanotubes

    Science.gov (United States)

    Kobotaeva, N. S.; Skorokhodova, T. S.; Ryabova, N. V.

    2015-03-01

    Catalytic systems for cumene oxidation were prepared on the basis of silver-activated carbon nanotubes. Silver lies on the surface of the carbon nanotubes in the nanocrystalline state and has a size of 15-20 nm. The use of the obtained catalytic systems in cumene oxidation with molecular oxygen allowed a considerable decrease in the oxidation temperature and an increase in selectivity.

  20. Propulsion Mechanism of Catalytic Microjet Engines

    Science.gov (United States)

    Fomin, Vladimir M.; Hippler, Markus; Magdanz, Veronika; Soler, Lluís; Sanchez, Samuel; Schmidt, Oliver G.

    2014-01-01

    We describe the propulsion mechanism of the catalytic microjet engines that are fabricated using rolled-up nanotech. Microjets have recently shown numerous potential applications in nanorobotics but currently there is a lack of an accurate theoretical model that describes the origin of the motion as well as the mechanism of self-propulsion. The geometric asymmetry of a tubular microjet leads to the development of a capillary force, which tends to propel a bubble toward the larger opening of the tube. Because of this motion in an asymmetric tube, there emerges a momentum transfer to the fluid. In order to compensate this momentum transfer, a jet force acting on the tube occurs. This force, which is counterbalanced by the linear drag force, enables tube velocities of the order of 100 μm/s. This mechanism provides a fundamental explanation for the development of driving forces that are acting on bubbles in tubular microjets. PMID:25177214