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Sample records for cerium oxide diesel

  1. Transformation of Cerium Oxide Nanoparticles from a Diesel Fuel Additive during Combustion in a Diesel Engine.

    Science.gov (United States)

    Dale, James G; Cox, Steven S; Vance, Marina E; Marr, Linsey C; Hochella, Michael F

    2017-02-21

    Nanoscale cerium oxide is used as a diesel fuel additive to reduce particulate matter emissions and increase fuel economy, but its fate in the environment has not been established. Cerium oxide released as a result of the combustion of diesel fuel containing the additive Envirox, which utilizes suspended nanoscale cerium oxide to reduce particulate matter emissions and increase fuel economy, was captured from the exhaust stream of a diesel engine and was characterized using a combination of bulk analytical techniques and high resolution transmission electron microscopy. The combustion process induced significant changes in the size and morphology of the particles; ∼15 nm aggregates consisting of 5-7 nm faceted crystals in the fuel additive became 50-300 nm, near-spherical, single crystals in the exhaust. Electron diffraction identified the original cerium oxide particles as cerium(IV) oxide (CeO2, standard FCC structure) with no detectable quantities of Ce(III), whereas in the exhaust the ceria particles had additional electron diffraction reflections indicative of a CeO2 superstructure containing ordered oxygen vacancies. The surfactant coating present on the cerium oxide particles in the additive was lost during combustion, but in roughly 30% of the observed particles in the exhaust, a new surface coating formed, approximately 2-5 nm thick. The results of this study suggest that pristine, laboratory-produced, nanoscale cerium oxide is not a good substitute for the cerium oxide released from fuel-borne catalyst applications and that future toxicity experiments and modeling will require the use/consideration of more realistic materials.

  2. Inhaled Diesel Emissions Generated with Cerium Oxide Nanoparticle Fuel Additive Induce Adverse Pulmonary and Systemic Effects

    Science.gov (United States)

    Diesel exhaust (DE) exposure induces adverse cardiopulmonary effects. Cerium oxide nanoparticles added to diesel fuel (DECe) increases fuel burning efficiency but leads to altered emission characteristics and potentially altered health effects. Here, we evaluated whether DECe res...

  3. Production of gaseous fuel from jatropha oil by cerium oxide based catalytic fuel reactor and its utilisation on diesel engine

    Directory of Open Access Journals (Sweden)

    Mylswamy Thirunavukkarasu

    2016-01-01

    Full Text Available In this study, an attempt is made to produce a hydrocarbon fuel from jatropha vegetable oil for Diesel engine applications. The “catalytic cracking” a process recently introduced by the researchers is chosen as an alternative method to trans-esterification process to match the fuel properties to diesel. Jatropha vegetable oil was cracked into a gas using the cerium oxide catalyst in a fixed bed catalytic reactor. The produced gas is introduced at constant rate into the inlet manifold of the Diesel engine. The experimental work was carried out in single cylinder water cooled direct injection Diesel engine coupled with eddy current dynamometer. The combustion parameters are measured by AVL combustion analyser. From the experimental results, the increase in brake thermal efficiency of the engine for full load was observed to be 10% (relative compared with diesel. Notably, emissions such as HC, CO, and smoke are reduced by 18%, 61%, and 18%, respectively, when compared with diesel.

  4. Interactive effects of cerium oxide and diesel exhaust nanoparticles on inducing pulmonary fibrosis

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jane Y.C., E-mail: jym1@cdc.gov [Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Young, Shih-Houng; Mercer, Robert R.; Barger, Mark; Schwegler-Berry, Diane [Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Ma, Joseph K. [School of Pharmacy, West Virginia University, Morgantown, WV 26506 (United States); Castranova, Vincent [Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States)

    2014-07-15

    Cerium compounds have been used as a fuel-borne catalyst to lower the generation of diesel exhaust particles (DEPs), but are emitted as cerium oxide nanoparticles (CeO{sub 2}) along with DEP in the diesel exhaust. The present study investigates the effects of the combined exposure to DEP and CeO{sub 2} on the pulmonary system in a rat model. Specific pathogen-free male Sprague–Dawley rats were exposed to CeO{sub 2} and/or DEP via a single intratracheal instillation and were sacrificed at various time points post-exposure. This investigation demonstrated that CeO{sub 2} induces a sustained inflammatory response, whereas DEP elicits a switch of the pulmonary immune response from Th1 to Th2. Both CeO{sub 2} and DEP activated AM and lymphocyte secretion of the proinflammatory cytokines IL-12 and IFN-γ, respectively. However, only DEP enhanced the anti-inflammatory cytokine IL-10 production in response to ex vivo LPS or Concanavalin A challenge that was not affected by the presence of CeO{sub 2}, suggesting that DEP suppresses host defense capability by inducing the Th2 immunity. The micrographs of lymph nodes show that the particle clumps in DEP + CeO{sub 2} were significantly larger than CeO{sub 2} or DEP, exhibiting dense clumps continuous throughout the lymph nodes. Morphometric analysis demonstrates that the localization of collagen in the lung tissue after DEP + CeO{sub 2} reflects the combination of DEP-exposure plus CeO{sub 2}-exposure. At 4 weeks post-exposure, the histological features demonstrated that CeO{sub 2} induced lung phospholipidosis and fibrosis. DEP induced lung granulomas that were not significantly affected by the presence of CeO{sub 2} in the combined exposure. Using CeO{sub 2} as diesel fuel catalyst may cause health concerns. - Highlights: • DEP induced acute lung inflammation and switched immune response from Th1 to Th2. • DEP induced lung granulomas were not affected by the presence of CeO{sub 2}. • CeO{sub 2} induced sustained lung

  5. The biological effects of subacute inhalation of diesel exhaust following addition of cerium oxide nanoparticles in atherosclerosis-prone mice

    Energy Technology Data Exchange (ETDEWEB)

    Cassee, Flemming R., E-mail: flemming.cassee@rivm.nl [National Institute for Public Health and the Environment, PO box 1, 3720 BA Bilthoven (Netherlands); Campbell, Arezoo, E-mail: acampbell@westernu.edu [Western University of Health Sciences, Pomona, CA (United States); Boere, A. John F., E-mail: john.boere@rivm.nl [National Institute for Public Health and the Environment, PO box 1, 3720 BA Bilthoven (Netherlands); McLean, Steven G., E-mail: smclean1@staffmail.ed.ac.uk [BHF/University Centre for Cardiovascular Sciences, University of Edinburgh, Edinburgh (United Kingdom); Duffin, Rodger, E-mail: Rodger.Duffin@ed.ac.uk [MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh (United Kingdom); Krystek, Petra, E-mail: petra.krystek@philips.com [Philips Innovation Services, Eindhoven (Netherlands); Gosens, Ilse, E-mail: Ilse.gosens@rivm.nl [National Institute for Public Health and the Environment, PO box 1, 3720 BA Bilthoven (Netherlands); Miller, Mark R., E-mail: Mark.Miller@ed.ac.uk [BHF/University Centre for Cardiovascular Sciences, University of Edinburgh, Edinburgh (United Kingdom)

    2012-05-15

    Background: Cerium oxide (CeO{sub 2}) nanoparticles improve the burning efficiency of fuel, however, little is known about health impacts of altered emissions from the vehicles. Methods: Atherosclerosis-prone apolipoprotein E knockout (ApoE{sup -/-}) mice were exposed by inhalation to diluted exhaust (1.7 mg/m{sup 3}, 20, 60 or 180 min, 5 day/week, for 4 weeks), from an engine using standard diesel fuel (DE) or the same diesel fuel containing 9 ppm cerium oxide nanoparticles (DCeE). Changes in hematological indices, clinical chemistry, atherosclerotic burden, tissue levels of inflammatory cytokines and pathology of the major organs were assessed. Results: Addition of CeO{sub 2} to fuel resulted in a reduction of the number (30%) and surface area (10%) of the particles in the exhaust, whereas the gaseous co-pollutants were increased (6-8%). There was, however, a trend towards an increased size and complexity of the atherosclerotic plaques following DE exposure, which was not evident in the DCeE group. There were no clear signs of altered hematological or pathological changes induced by either treatment. However, levels of proinflammatory cytokines were modulated in a brain region and liver following DCeE exposure. Conclusions: These results imply that addition of CeO{sub 2} nanoparticles to fuel decreases the number of particles in exhaust and may reduce atherosclerotic burden associated with exposure to standard diesel fuel. From the extensive assessment of biological parameters performed, the only concerning effect of cerium addition was a slightly raised level of cytokines in a region of the central nervous system. Overall, the use of cerium as a fuel additive may be a potentially useful way to limit the health effects of vehicle exhaust. However, further testing is required to ensure that such an approach is not associated with a chronic inflammatory response which may eventually cause long-term health effects.

  6. EMISSION REDUCTION FROM A DIESEL ENGINE FUELED BY CERIUM OXIDE NANO-ADDITIVES USING SCR WITH DIFFERENT METAL OXIDES COATED CATALYTIC CONVERTER

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    B. JOTHI THIRUMAL

    2015-11-01

    Full Text Available This paper reports the results of experimental investigations on the influence of the addition of cerium oxide in nanoparticle form on the major physiochemical properties and the performance of diesel. The fuel is modified by dispersing the catalytic nanoparticle by ultrasonic agitation. The physiochemical properties of sole diesel fuel and modified fuel are tested with ASTM standard procedures. The effects of the additive nanoparticles on the individual fuel properties, the engine performance, and emissions are studied, and the dosing level of the additive is optimized. Cerium oxide acts as an oxygen-donating catalyst and provides oxygen for the oxidation of CO during combustion. The active energy of cerium oxide acts to burn off carbon deposits within the engine cylinder at the wall temperature and prevents the deposition of non-polar compounds on the cylinder wall which results in reduction in HC emission by 56.5%. Furthermore, a low-cost metal oxide coated SCR (selective catalyst reduction, using urea as a reducing agent, along with different types of CC (catalytic converter, has been implemented in the exhaust pipe to reduce NOx. It was observed that a reduction in NOx emission is 50–60%. The tests revealed that cerium oxide nanoparticles can be used as an additive in diesel to improve complete combustion of the fuel and reduce the exhaust emissions significantly.

  7. Initial in vitro screening approach to investigate the potential health and environmental hazards of Envirox™ – a nanoparticulate cerium oxide diesel fuel additive

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    Whittingham Andrew

    2007-12-01

    Full Text Available Abstract Nanotechnology is the new industrial revolution of the 21st Century as the various processes lead to radical improvements in medicine, manufacturing, energy production, land remediation, information technology and many other everyday products and applications. With this revolution however, there are undoubted concerns for health, safety and the environment which arise from the unique nature of materials and processes at the nanometre scale. The in vitro assays used in the screening strategy are all validated, internationally accepted protocols and provide a useful indication of potential toxicity of a chemical as a result of effects on various toxicological endpoints such as local site of contact (dermal irritation, general cytotoxicity and mutagenicity. The initial in vitro screening strategy described in this paper to investigate the potential health implications, if any, which may arise following exposure to one specific application of nanoparticulate cerium oxide used as a diesel fuel borne catalyst, reflects a precautionary approach and the results will inform judgement on how best to proceed to ensure safe use.

  8. Formulation and method for preparing gels comprising hydrous cerium oxide

    Science.gov (United States)

    Collins, Jack L; Chi, Anthony

    2013-05-07

    Formulations useful for preparing hydrous cerium oxide gels contain a metal salt including cerium, an organic base, and a complexing agent. Methods for preparing gels containing hydrous cerium oxide include heating a formulation to a temperature sufficient to induce gel formation, where the formulation contains a metal salt including cerium, an organic base, and a complexing agent.

  9. Some Environmentally Relevant Reactions of Cerium Oxide

    Directory of Open Access Journals (Sweden)

    Janoš Pavel

    2014-12-01

    Full Text Available Reactive forms of cerium oxide were prepared by a thermal decomposition of various precursors, namely carbonates, oxalates and citrates, commercially available nanocrystalline cerium oxide (nanoceria was involved in the study for comparison. Scanning electron microscopy (SEM and x-ray diffraction analysis (XRD were used to examine the morphology and crystallinity of the samples, respectively, whereas the Brunauer-Emmett-Teller (BET method of nitrogen adsorption was used to determine surface areas. Interactions of cerium oxide with some phosphorus-containing compounds were investigated. Some of the examined samples, especially those prepared by annealing from carbonate precursors, exhibited an outstanding ability to destroy highly toxic organophosphates, such as pesticides (parathion methyl, or nerve agents (soman, VX. There were identified some relations between the degradation efficiency of cerium oxides and their crystallinity. It was also shown that cerium oxide is able to destroy one of widely used flame retardants - triphenyl phosphate. A phosphatase-mimetic activity of various cerium oxides was examined with the aid of a standardized phosphatase test.

  10. Induction of pulmonary fibrosis by cerium oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jane Y., E-mail: jym1@cdc.gov [Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Mercer, Robert R.; Barger, Mark; Schwegler-Berry, Diane; Scabilloni, James [Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Ma, Joseph K. [School of Pharmacy, West Virginia University, Morgantown, WV 26506 (United States); Castranova, Vincent [Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States)

    2012-08-01

    Cerium compounds have been used as a diesel engine catalyst to lower the mass of diesel exhaust particles, but are emitted as cerium oxide (CeO{sub 2}) nanoparticles in the diesel exhaust. In a previous study, we have demonstrated a wide range of CeO{sub 2}-induced lung responses including sustained pulmonary inflammation and cellular signaling that could lead to pulmonary fibrosis. In this study, we investigated the fibrogenic responses induced by CeO{sub 2} in a rat model at various time points up to 84 days post-exposure. Male Sprague Dawley rats were exposed to CeO{sub 2} by a single intratracheal instillation. Alveolar macrophages (AM) were isolated by bronchial alveolar lavage (BAL). AM-mediated cellular responses, osteopontin (OPN) and transform growth factor (TGF)-β1 in the fibrotic process were investigated. The results showed that CeO{sub 2} exposure significantly increased fibrotic cytokine TGF-β1 and OPN production by AM above controls. The collagen degradation enzymes, matrix metalloproteinase (MMP)-2 and -9 and the tissue inhibitor of MMP were markedly increased in the BAL fluid at 1 day- and subsequently declined at 28 days after exposure, but remained much higher than the controls. CeO{sub 2} induced elevated phospholipids in BAL fluid and increased hydroxyproline content in lung tissue in a dose- and time-dependent manner. Immunohistochemical analysis showed MMP-2, MMP-9 and MMP-10 expressions in fibrotic regions. Morphological analysis noted increased collagen fibers in the lungs exposed to a single dose of 3.5 mg/kg CeO{sub 2} and euthanized at 28 days post-exposure. Collectively, our studies show that CeO{sub 2} induced fibrotic lung injury in rats, suggesting it may cause potential health effects. -- Highlights: ► Cerium oxide exposure significantly affected the following parameters in the lung. ► Induced fibrotic cytokine OPN and TGF-β1 production and phospholipidosis. ► Caused imbalance of the MMP-9/ TIMP-1 ratio that favors fibrosis

  11. Nanocrystalline cerium oxide materials for solid fuel cell systems

    Science.gov (United States)

    Brinkman, Kyle S

    2015-05-05

    Disclosed are solid fuel cells, including solid oxide fuel cells and PEM fuel cells that include nanocrystalline cerium oxide materials as a component of the fuel cells. A solid oxide fuel cell can include nanocrystalline cerium oxide as a cathode component and microcrystalline cerium oxide as an electrolyte component, which can prevent mechanical failure and interdiffusion common in other fuel cells. A solid oxide fuel cell can also include nanocrystalline cerium oxide in the anode. A PEM fuel cell can include cerium oxide as a catalyst support in the cathode and optionally also in the anode.

  12. Particulate Emissions from the Combustion of Diesel Fuel with a Fuel-Borne Nanoparticulate Cerium Catalyst

    Science.gov (United States)

    Conny, J. M.; Willis, R. D.; Weinstein, J. P.; Krantz, T.; King, C.

    2013-12-01

    To address the adverse impacts on health and climate from the use of diesel-fueled vehicles, a number of technological solutions have been developed for reducing diesel soot emissions and to improve fuel economy. One such solution is the use fuel-borne metal oxide catalysts. Of current interest are commercially-available fuel additives consisting of nanoparticulate cerium oxide (CeO2). In response to the possible use of CeO2-containing fuels in on-road vehicles in the U.S., the Environmental Protection Agency is conducting research to address the potential toxicity and environmental effects of particulate CeO2 emitted with diesel soot. In this study, emissions from a diesel-fueled electric generator were size-segregated on polished silicon wafers in a nanoparticle cascade impactor. The diesel fuel contained 10 ppm Ce by weight in the form of crystalline CeO2 nanoparticles 4 nm to 7.5 nm in size. Primary CeO2 nanoparticles were observed in the diesel emissions as well as CeO2 aggregates encompassing a broad range of sizes up to at least 200 nm. We report the characterization of individual particles from the size-resolved samples with focused ion-beam scanning electron microscopy and energy-dispersive x-ray spectroscopy. Results show a dependency between the impactor size range and CeO2 agglomeration state: in the larger size fractions of the impactor (e.g., 560 nm to 1000 nm) CeO2 nanoparticles were predominantly attached to soot particles. In the smaller size fractions of the impactor (e.g., 100 nm to 320 nm), CeO2 aggregates tended to be larger and unattached to soot. The result is important because the deposition of CeO2 nanoparticles attached to soot particles in the lung or on environmental surfaces such as plant tissue will likely present different consequences than the deposition of unagglomerated CeO2 particles. Disclaimer The U.S. Environmental Protection Agency through its Office of Research and Development funded and collaborated in the research described

  13. Interactional effect of cerium and manganese on NO catalytic oxidation.

    Science.gov (United States)

    Liang, Yanli; Huang, Yufen; Zhang, Hailong; Lan, Li; Zhao, Ming; Gong, Maochu; Chen, Yaoqiang; Wang, Jianli

    2017-04-01

    To preferably catalyze the oxidation of NO to NO2 in diesel after-treatment system, a series of CeO2-MnO x composite oxides was supported on silica-alumina material by the co-impregnation method. The maximum conversion of NO of the catalyst with a Ce/Mn weight ratio of 5:5 was improved by around 40%, compared to the supported manganese-only or cerium-only sample. And its maximum reaction rate was 0.056 μmol g(-1) s(-1) at 250 °C at the gas hourly space velocity of 30,000 h(-1). The experimental results suggested that Ce-Mn solid solution was formed, which could modulate the valence state of cerium and manganese and exhibit great redox properties. Moreover, the strong interaction between ceria and manganese resulted in the largest desorption amount of strong chemical oxygen and oxygen vacancies, leading to the maximum O α area ratio of 62.26% from the O 1s result. These effective oxygen species could be continually transferred to the surface, leading to the best NO catalytic activity of 5Ce5Mn/SA catalyst. Graphical abstract.

  14. Structural, optical, morphological and dielectric properties of cerium oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Prabaharan, Devadoss Mangalam Durai Manoharadoss [Department of Physics, NPR College of Engineering and Technology, Natham, Dindigul, Tamil Nadu (India); Sadaiyandi, Karuppasamy [Department of Physics, Alagappa Government Arts College, Karaikudi, Sivaganga, Tamil Nadu (India); Mahendran, Manickam [Department of Physics, Thiagarajar College of Engineering, Madurai, Tamil Nadu (India); Sagadevan, Suresh, E-mail: duraiphysics2011@gmail.com [Department of Physics, AMET University (India)

    2016-03-15

    Cerium oxide (CeO{sub 2}) nanoparticles were prepared by the precipitation method. The average crystallite size of cerium oxide nanoparticles was calculated from the X-ray diffraction (XRD) pattern and found to be 11 nm. The FT-IR spectrum clearly indicated the strong presence of cerium oxide nanoparticles. Raman spectrum confirmed the cubic nature of the cerium oxide nanoparticles. The Scanning Electron Microscopy (SEM) analysis showed that the nanoparticles agglomerated forming spherical-shaped particles. The Transmission Electron Microscopic (TEM) analysis confirmed the prepared cerium oxide nanoparticles with the particle size being found to be 16 nm. The optical absorption spectrum showed a blue shift by the cerium oxide nanoparticles due to the quantum confinement effect. The dielectric properties of cerium oxide nanoparticles were studied for different frequencies at different temperatures. The dielectric constant and the dielectric loss of the cerium oxide nanoparticles decreased with increase in frequency. The AC electrical conductivity study revealed that the conduction depended on both the frequency and the temperature. (author)

  15. Photodissociation of Cerium Oxide Nanocluster Cations.

    Science.gov (United States)

    Akin, S T; Ard, S G; Dye, B E; Schaefer, H F; Duncan, M A

    2016-04-21

    Cerium oxide cluster cations, CexOy(+), are produced via laser vaporization in a pulsed nozzle source and detected with time-of-flight mass spectrometry. The mass spectrum displays a strongly preferred oxide stoichiometry for each cluster with a specific number of metal atoms x, with x ≤ y. Specifically, the most prominent clusters correspond to the formula CeO(CeO2)n(+). The cluster cations are mass selected and photodissociated with a Nd:YAG laser at either 532 or 355 nm. The prominent clusters dissociate to produce smaller species also having a similar CeO(CeO2)n(+) formula, always with apparent leaving groups of (CeO2). The production of CeO(CeO2)n(+) from the dissociation of many cluster sizes establishes the relative stability of these clusters. Furthermore, the consistent loss of neutral CeO2 shows that the smallest neutral clusters adopt the same oxidation state (IV) as the most common form of bulk cerium oxide. Clusters with higher oxygen content than the CeO(CeO2)n(+) masses are present with much lower abundance. These species dissociate by the loss of O2, leaving surviving clusters with the CeO(CeO2)n(+) formula. Density functional theory calculations on these clusters suggest structures composed of stable CeO(CeO2)n(+) cores with excess oxygen bound to the surface as a superoxide unit (O2(-)).

  16. Heteroaggregation of cerium oxide nanoparticles and nanoparticles of pyrolyzed biomass

    Science.gov (United States)

    Heteroaggregation with indigenous particles is an important process controlling the mobility of engineered nanomaterials in the environment. We studied heteroaggregation of cerium oxide nanoparticles (n-CeO2), which are widely used commercially, with nanoparticles of pyrogenic carbonaceous material ...

  17. Cerium extraction by metallothermic reduction using cerium oxide powder injection

    Institute of Scientific and Technical Information of China (English)

    J.S. Luna A; A. Flores V; R. Mu(n)iz V; A.F. Fuentes; J. Torres; N. Rodríuez R; J.C. Ortiz; P.Orozco

    2011-01-01

    This work presented the feasibility of cerium recovery by Al-Mg alloy through the metallothermic reduction of CeO2 to obtain a master alloy Al-4%Ce. The master alloy obtained in this investigation was for the grain refinement and modification of Al-Si alloys. The reagent was incorporated into a molten alloy using the submerged powder injection technique, and metallic samples were obtained during injection. Chemical and microstructural analyses (by inductively coupled plasma (ICP) and scanning electron microscopy (SEM), respectively) confirmed the possibility of Ce uptake in the bath (0 to 4 wt.%), as CeO2 was reduced through metallothermic reactions in the molten alloys.Based on the characterization of reaction products, the sequence of the reaction was proposed.

  18. Uptake and accumulation of bulk and nanosized cerium oxide particles and ionic cerium by radish (Raphanus sativus L.).

    Science.gov (United States)

    Zhang, Weilan; Ebbs, Stephen D; Musante, Craig; White, Jason C; Gao, Cunmei; Ma, Xingmao

    2015-01-21

    The potential toxicity and accumulation of engineered nanomaterials (ENMs) in agricultural crops has become an area of great concern and intense investigation. Interestingly, although below-ground vegetables are most likely to accumulate the highest concentrations of ENMs, little work has been done investigating the potential uptake and accumulation of ENMs for this plant group. The overall objective of this study was to evaluate how different forms of cerium (bulk cerium oxide, cerium oxide nanoparticles, and the cerium ion) affected the growth of radish (Raphanus sativus L.) and accumulation of cerium in radish tissues. Ionic cerium (Ce(3+)) had a negative effect on radish growth at 10 mg CeCl3/L, whereas bulk cerium oxide (CeO2) enhanced plant biomass at the same concentration. Treatment with 10 mg/L cerium oxide nanoparticles (CeO2 NPs) had no significant effect on radish growth. Exposure to all forms of cerium resulted in the accumulation of this element in radish tissues, including the edible storage root. However, the accumulation patterns and their effect on plant growth and physiological processes varied with the characteristics of cerium. This study provides a critical frame of reference on the effects of CeO2 NPs versus their bulk and ionic counterparts on radish growth.

  19. Environmental Geochemistry of Cerium: Applications and Toxicology of Cerium Oxide Nanoparticles

    OpenAIRE

    2015-01-01

    Cerium is the most abundant of rare-earth metals found in the Earth’s crust. Several Ce-carbonate, -phosphate, -silicate, and -(hydr)oxide minerals have been historically mined and processed for pharmaceutical uses and industrial applications. Of all Ce minerals, cerium dioxide has received much attention in the global nanotechnology market due to their useful applications for catalysts, fuel cells, and fuel additives. A recent mass flow modeling study predicted that a major source of CeO2 na...

  20. OXIDATIVE DNA DAMAGE IN DIESEL BUS MECHANICS

    Science.gov (United States)

    Rationale: Diesel exposure has been associated with adverse health effects, including susceptibility to asthma, allergy and cancer. Previous epidemiological studies demonstrated increased cancer incidence among workers exposed to diesel. This is likely due to oxid...

  1. Optical and electrical studies of cerium mixed oxides

    Science.gov (United States)

    Sherly, T. R.; Raveendran, R.

    2014-10-01

    The fast development in nanotechnology makes enthusiastic interest in developing nanomaterials having tailor made properties. Cerium mixed oxide materials have received great attention due to their UV absorption property, high reactivity, stability at high temperature, good electrical property etc and these materials find wide applications in solid oxide fuel cells, solar control films, cosmetics, display units, gas sensors etc. In this study cerium mixed oxide compounds were prepared by co-precipitation method. All the samples were doped with Zn (II) and Fe (II). Preliminary characterizations such as XRD, SEM / EDS, TEM were done. UV - Vis, Diffuse reflectance, PL, FT-IR, Raman and ac conductivity studies of the samples were performed.

  2. Optical and electrical studies of cerium mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Sherly, T. R., E-mail: trsherly@gmail.com [Post Graduate Department of Physics, Sanathana Dharma College, Alappuzha, Kerala (India); Raveendran, R. [Nanoscience Research Laboratory, Sree Narayana College, Kollam, Kerala 691001 (India)

    2014-10-15

    The fast development in nanotechnology makes enthusiastic interest in developing nanomaterials having tailor made properties. Cerium mixed oxide materials have received great attention due to their UV absorption property, high reactivity, stability at high temperature, good electrical property etc and these materials find wide applications in solid oxide fuel cells, solar control films, cosmetics, display units, gas sensors etc. In this study cerium mixed oxide compounds were prepared by co-precipitation method. All the samples were doped with Zn (II) and Fe (II). Preliminary characterizations such as XRD, SEM / EDS, TEM were done. UV - Vis, Diffuse reflectance, PL, FT-IR, Raman and ac conductivity studies of the samples were performed.

  3. Synthesis and characterization of magnesium doped cerium oxide for the fuel cell application

    Science.gov (United States)

    Kumar, Amit; Kumari, Monika; Kumar, Mintu; Kumar, Sacheen; Kumar, Dinesh

    2016-05-01

    Cerium oxide has attained much attentions in global nanotechnology market due to valuable application for catalytic, fuel additive, and widely as electrolyte in solid oxide fuel cell. Doped cerium oxide has large oxygen vacancies that allow for greater reactivity and faster ion transport. These properties make cerium oxide suitable material for SOFCs application. Cerium oxide electrolyte requires lower operation temperature which shows improvement in processing and the fabrication technique. In our work, we synthesized magnesium doped cerium oxide by the co-precipitation method. With the magnesium doping catalytic reactivity of CeO2 was increased. Synthesized nanoparticle were characterized by the XRD and UV absorption techniques.

  4. Molecular and physiological responses to titanium dioxide and cerium oxide nanoparticles in arabidopsis

    Science.gov (United States)

    - Changes in tissue transcriptomes and productivity of Arabidopsis thaliana were investigated during exposure of plants to two widely-used engineered metal oxide nanoparticles, titanium dioxide (nano-titanium) and cerium dioxide (nano-cerium). Microarray analyses confirmed that e...

  5. Molecular and physiological responses to titanium dioxide and cerium oxide nanoparticles in arabidopsis

    Science.gov (United States)

    - Changes in tissue transcriptomes and productivity of Arabidopsis thaliana were investigated during exposure of plants to two widely-used engineered metal oxide nanoparticles, titanium dioxide (nano-titanium) and cerium dioxide (nano-cerium). Microarray analyses confirmed that e...

  6. Determination of Impurity Elements in Pure Cerium Oxide Product

    Institute of Scientific and Technical Information of China (English)

    Li Peizhong; Chen Limin; Li Jie

    2004-01-01

    Determination of the rare earth impurity in pure cerium oxide is done by ICP-MS.The interference and other factors which affect analytical results were discussed.The accuracy are between 0.81% ~ 11.98% and the recoveries of standard addition are 96% ~ 112.5%.This method can meet the demand for product inspection.

  7. Cerium fluoride nanoparticles protect cells against oxidative stress.

    Science.gov (United States)

    Shcherbakov, Alexander B; Zholobak, Nadezhda M; Baranchikov, Alexander E; Ryabova, Anastasia V; Ivanov, Vladimir K

    2015-05-01

    A novel facile method of non-doped and fluorescent terbium-doped cerium fluoride stable aqueous sols synthesis is proposed. Intense green luminescence of CeF3:Tb nanoparticles can be used to visualize these nanoparticles' accumulation in cells using confocal laser scanning microscopy. Cerium fluoride nanoparticles are shown for the first time to protect both organic molecules and living cells from the oxidative action of hydrogen peroxide. Both non-doped and terbium-doped CeF3 nanoparticles are shown to provide noteworthy protection to cells against the vesicular stomatitis virus. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Processing and Characterization of Sol-Gel Cerium Oxide Microspheres

    Energy Technology Data Exchange (ETDEWEB)

    McClure, Zachary D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Padilla Cintron, Cristina [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-09-27

    Of interest to space exploration and power generation, Radioisotope Thermoelectric Generators (RTGs) can provide long-term power to remote electronic systems without the need for refueling or replacement. Plutonium-238 (Pu-238) remains one of the more promising materials for thermoelectric power generation due to its high power density, long half-life, and low gamma emissions. Traditional methods for processing Pu-238 include ball milling irregular precipitated powders before pressing and sintering into a dense pellet. The resulting submicron particulates of Pu-238 quickly accumulate and contaminate glove boxes. An alternative and dust-free method for Pu-238 processing is internal gelation via sol-gel techniques. Sol-gel methodology creates monodisperse and uniform microspheres that can be packed and pressed into a pellet. For this study cerium oxide microspheres were produced as a surrogate to Pu-238. The similar electronic orbitals between cerium and plutonium make cerium an ideal choice for non-radioactive work. Before the microspheres can be sintered and pressed they must be washed to remove the processing oil and any unreacted substituents. An investigation was performed on the washing step to find an appropriate wash solution that reduced waste and flammable risk. Cerium oxide microspheres were processed, washed, and characterized to determine the effectiveness of the new wash solution.

  9. Antibacterial activity of polymer coated cerium oxide nanoparticles.

    Directory of Open Access Journals (Sweden)

    Vishal Shah

    Full Text Available Cerium oxide nanoparticles have found numerous applications in the biomedical industry due to their strong antioxidant properties. In the current study, we report the influence of nine different physical and chemical parameters: pH, aeration and, concentrations of MgSO(4, CaCl(2, KCl, natural organic matter, fructose, nanoparticles and Escherichia coli, on the antibacterial activity of dextran coated cerium oxide nanoparticles. A least-squares quadratic regression model was developed to understand the collective influence of the tested parameters on the anti-bacterial activity and subsequently a computer-based, interactive visualization tool was developed. The visualization allows us to elucidate the effect of each of the parameters in combination with other parameters, on the antibacterial activity of nanoparticles. The results indicate that the toxicity of CeO(2 NPs depend on the physical and chemical environment; and in a majority of the possible combinations of the nine parameters, non-lethal to the bacteria. In fact, the cerium oxide nanoparticles can decrease the anti-bacterial activity exerted by magnesium and potassium salts.

  10. Environmental geochemistry of cerium: applications and toxicology of cerium oxide nanoparticles.

    Science.gov (United States)

    Dahle, Jessica T; Arai, Yuji

    2015-01-23

    Cerium is the most abundant of rare-earth metals found in the Earth's crust. Several Ce-carbonate, -phosphate, -silicate, and -(hydr)oxide minerals have been historically mined and processed for pharmaceutical uses and industrial applications. Of all Ce minerals, cerium dioxide has received much attention in the global nanotechnology market due to their useful applications for catalysts, fuel cells, and fuel additives. A recent mass flow modeling study predicted that a major source of CeO2 nanoparticles from industrial processing plants (e.g., electronics and optics manufactures) is likely to reach the terrestrial environment such as landfills and soils. The environmental fate of CeO2 nanoparticles is highly dependent on its physcochemical properties in low temperature geochemical environment. Though there are needs in improving the analytical method in detecting/quantifying CeO2 nanoparticles in different environmental media, it is clear that aquatic and terrestrial organisms have been exposed to CeO2 NPs, potentially yielding in negative impact on human and ecosystem health. Interestingly, there has been contradicting reports about the toxicological effects of CeO2 nanoparticles, acting as either an antioxidant or reactive oxygen species production-inducing agent). This poses a challenge in future regulations for the CeO2 nanoparticle application and the risk assessment in the environment.

  11. Direct growth of cerium oxide nanorods on diverse substrates for superhydrophobicity and corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Jun; Jang, Hanmin; Lee, Kwan-Soo [School of Mechanical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, Dong Rip, E-mail: dongrip@hanyang.ac.kr [School of Mechanical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Institute of Nano Science and Technology, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2015-06-15

    Graphical abstract: - Highlights: • Cerium oxide nanorods were uniformly grown on diverse substrates. • Changes in growth conditions led to morphology evolution of cerium oxide nanostructures. • The grown cerium oxide nanostructures were single or poly crystalline. • Direct growth of cerium oxide nanorods made the diverse substrates superhydrophobic and anti-corrosive without any surface modifiers. - Abstract: Superhydrophobic surfaces with anti-corrosion properties have attracted great interest in many industrial fields, particularly to enhance the thermal performance of offshore applications such as heat exchangers, pipelines, power plants, and platform structures. Nanostructures with hydrophobic materials have been widely utilized to realize superhydrophobicity of surfaces, and cerium oxide has been highlighted due to its good corrosion resistive and intrinsically hydrophobic properties. However, few studies of direct growth of cerium oxide nanostructures on diverse substrates have been reported. Herein we report a facile hydrothermal method to directly grow cerium oxide nanorods on diverse substrates, such as aluminum alloy, stainless steel, titanium, and silicon. Diverse substrates with cerium oxide nanorods exhibited superhydrophobicity with no hydrophobic modifiers on their surfaces, and showed good corrosion resistive properties in corrosive medium. We believe our method could pave the way for realization of scalable and sustainable corrosion resistive superhydrophobic surfaces in many industrial fields.

  12. Health Effects Associated with Inhalation Exposure to Diesel Emission Generated with and without CeO2 Nano Fuel Additive

    Science.gov (United States)

    Diesel exhaust (DE) exposure induces adverse cardiopulmonary effects. Addition of nano cerium (Ce) oxide additive to diesel fuel (DECe) increases fuel burning efficiency resulting in altered emission characteristics and potentially altered health effects. We hypothesized that inh...

  13. Mechanism of chlorinating lanthanum oxide and cerium oxide with ammonium chloride

    Institute of Scientific and Technical Information of China (English)

    朱国才; 李赋屏; 肖明贵

    2003-01-01

    Using ammonium chloride(NH4Cl)as a chlorinating agent,the effects of chlorinating temperature,at 300℃ for 90 min,and have no advantage to chlorination of lanthanum and cerium oxides at higher temperature.The thermal decomposition of LaCl3 and CeCl3 is carried out to explore the mechanism of chlorinating lanthanum and cerium oxides.At the same time,the chlorination of lanthanum and cerium oxides is not devoted to the HCl decomposed from NH4Cl,but to NH4Cl directly taking part in the chlorination of La2O3 and CeO2.The lanthanum and cerium oxides in chlorination firstly form intermediate LaOCl and CeOCl,and then transfer to LaCl3 and CeCl3,fither prove the existence of the intermediates LaOCl and CeOCl.Therefore the chlorinating temperature and time should strictly be controlled when the lanthanum oxide and cerium oxide are chlorinated with NH4 Cl.And over-dosage of NH4 Cl should be also applied in the process of chlorination.

  14. Functionalization of nanostructured cerium oxide films with histidine.

    Science.gov (United States)

    Tsud, Nataliya; Bercha, Sofiia; Acres, Robert G; Vorokhta, Mykhailo; Khalakhan, Ivan; Prince, Kevin C; Matolín, Vladimír

    2015-01-28

    The surfaces of polycrystalline cerium oxide films were modified by histidine adsorption under vacuum and characterized by the synchrotron based techniques of core and valence level photoemission, resonant photoemission and near edge X-ray absorption spectroscopy, as well as atomic force microscopy. Histidine is strongly bound to the oxide surface in the anionic form through the deprotonated carboxylate group, and forms a disordered molecular adlayer. The imidazole ring and the amino side group do not form bonds with the substrate but are involved in the intermolecular hydrogen bonding which stabilizes the molecular adlayer. The surface reaction with histidine results in water desorption accompanied by oxide reduction, which is propagated into the bulk of the film. Previously studied, well-characterized surfaces are a guide to the chemistry of the present polycrystalline surface and histidine bonds via the carboxylate group in both cases. In contrast, bonding via the imidazole group occurs on the well-ordered surface but not in the present case. The morphology and structure of the cerium oxide are decisive factors which define the adsorption geometry of the histidine adlayer.

  15. Superconductive articles including cerium oxide layer

    Science.gov (United States)

    Wu, Xin D.; Muenchausen, Ross E.

    1993-01-01

    A ceramic superconductor comprising a metal oxide substrate, a ceramic high temperature superconductive material, and a intermediate layer of a material having a cubic crystal structure, said layer situated between the substrate and the superconductive material is provided, and a structure for supporting a ceramic superconducting material is provided, said structure comprising a metal oxide substrate, and a layer situated over the surface of the substrate to substantially inhibit interdiffusion between the substrate and a ceramic superconducting material deposited upon said structure.

  16. Cerium oxide based nanometric powders: synthesis and characterization

    Directory of Open Access Journals (Sweden)

    Ninić M.

    2007-01-01

    Full Text Available Nanometric powders of solid solutions of cerium oxide were obtained by a modified glycine nitrate procedure. Solid solutions of the host compound CeO2 with one or more dopants in the lattice were synthesized. Rare earth cations (Re=Yb, Gd and Sm were added to ceria in total concentration of x= 0.2 that was kept constant. The criterion in doping was to keep the value of lattice parameter of ceria unchanged. The lattice parameters were calculated by using the model that takes into account the existence of oxygen vacancies in the structure.

  17. Fabrication of Cerium Oxide and Uranium Oxide Microspheres for Space Nuclear Power Applications

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey A. Katalenich; Michael R. Hartman; Robert C. O' Brien

    2013-02-01

    Cerium oxide and uranium oxide microspheres are being produced via an internal gelation sol-gel method to investigate alternative fabrication routes for space nuclear fuels. Depleted uranium and non-radioactive cerium are being utilized as surrogates for plutonium-238 (Pu-238) used in radioisotope thermoelectric generators and for enriched uranium required by nuclear thermal rockets. While current methods used to produce Pu-238 fuels at Los Alamos National Laboratory (LANL) involve the generation of fine powders that pose a respiratory hazard and have a propensity to contaminate glove boxes, the sol-gel route allows for the generation of oxide microsphere fuels through an aqueous route. The sol-gel method does not generate fine powders and may require fewer processing steps than the LANL method with less operator handling. High-quality cerium dioxide microspheres have been fabricated in the desired size range and equipment is being prepared to establish a uranium dioxide microsphere production capability.

  18. Single crystal to single crystal transformation and hydrogen-atom transfer upon oxidation of a cerium coordination compound.

    Science.gov (United States)

    Williams, Ursula J; Mahoney, Brian D; Lewis, Andrew J; DeGregorio, Patrick T; Carroll, Patrick J; Schelter, Eric J

    2013-04-15

    Trivalent and tetravalent cerium compounds of the octamethyltetraazaannulene (H2omtaa) ligand have been synthesized. Electrochemical analysis shows a strong thermodynamic preference for the formal cerium(IV) oxidation state. Oxidation of the cerium(III) congener Ce(Homtaa)(omtaa) occurs by hydrogen-atom transfer that includes a single crystal to single crystal transformation upon exposure to an ambient atmosphere.

  19. Altering properties of cerium oxide thin films by Rh doping

    Energy Technology Data Exchange (ETDEWEB)

    Ševčíková, Klára, E-mail: klarak.sevcikova@seznam.cz [Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Charles University in Prague, V Holešovičkách 2, 180 00 Prague 8 (Czech Republic); NIMS Beamline Station at SPring-8, National Institute for Materials Science, Sayo, Hyogo 679-5148 (Japan); Nehasil, Václav, E-mail: nehasil@mbox.troja.mff.cuni.cz [Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Charles University in Prague, V Holešovičkách 2, 180 00 Prague 8 (Czech Republic); Vorokhta, Mykhailo, E-mail: vorohtam@gmail.com [Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Charles University in Prague, V Holešovičkách 2, 180 00 Prague 8 (Czech Republic); Haviar, Stanislav, E-mail: stanislav.haviar@gmail.com [Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Charles University in Prague, V Holešovičkách 2, 180 00 Prague 8 (Czech Republic); Matolín, Vladimír, E-mail: matolin@mbox.troja.mff.cuni.cz [Faculty of Mathematics and Physics, Department of Surface and Plasma Science, Charles University in Prague, V Holešovičkách 2, 180 00 Prague 8 (Czech Republic); and others

    2015-07-15

    Highlights: • Thin films of ceria doped by rhodium deposited by RF magnetron sputtering. • Concentration of rhodium has great impact on properties of Rh–CeO{sub x} thin films. • Intensive oxygen migration in films with low concentration of rhodium. • Oxygen migration suppressed in films with high amount of Rh dopants. - Abstract: Ceria containing highly dispersed ions of rhodium is a promising material for catalytic applications. The Rh–CeO{sub x} thin films with different concentrations of rhodium were deposited by RF magnetron sputtering and were studied by soft and hard X-ray photoelectron spectroscopies, Temperature programmed reaction and X-ray powder diffraction techniques. The sputtered films consist of rhodium–cerium mixed oxide where cerium exhibits a mixed valency of Ce{sup 4+} and Ce{sup 3+} and rhodium occurs in two oxidation states, Rh{sup 3+} and Rh{sup n+}. We show that the concentration of rhodium has a great influence on the chemical composition, structure and reducibility of the Rh–CeO{sub x} thin films. The films with low concentrations of rhodium are polycrystalline, while the films with higher amount of Rh dopants are amorphous. The morphology of the films strongly influences the mobility of oxygen in the material. Therefore, varying the concentration of rhodium in Rh–CeO{sub x} thin films leads to preparing materials with different properties.

  20. Transcriptome Changes in Douglas-fir (Pseudotsuga menziesii) Induced by Exposure to Diesel Emissions Generated with CeO2 Nanoparticle Fuel Additive

    Science.gov (United States)

    When cerium oxide nanoparticles are added to diesel fuel, fuel burning efficiency increases, producing emissions (DECe) with characteristics that differ from conventional diesel exhaust (DE). It has previously been shown that DECe induces more adverse pulmonary effects in rats on...

  1. Cerium fluoride nanoparticles protect cells against oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Shcherbakov, Alexander B.; Zholobak, Nadezhda M. [Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Kyiv D0368 (Ukraine); Baranchikov, Alexander E. [Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); Ryabova, Anastasia V. [Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow 115409 (Russian Federation); Ivanov, Vladimir K., E-mail: van@igic.ras.ru [Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); National Research Tomsk State University, Tomsk 634050 (Russian Federation)

    2015-05-01

    A novel facile method of non-doped and fluorescent terbium-doped cerium fluoride stable aqueous sols synthesis is proposed. Intense green luminescence of CeF{sub 3}:Tb nanoparticles can be used to visualize these nanoparticles' accumulation in cells using confocal laser scanning microscopy. Cerium fluoride nanoparticles are shown for the first time to protect both organic molecules and living cells from the oxidative action of hydrogen peroxide. Both non-doped and terbium-doped CeF{sub 3} nanoparticles are shown to provide noteworthy protection to cells against the vesicular stomatitis virus. - Highlights: • Facile method of CeF{sub 3} and CeF{sub 3}:Tb stable aqueous sols synthesis is proposed. • Naked CeF{sub 3} nanoparticles are shown to be non-toxic and to protect cells from the action of H{sub 2}O{sub 2}. • CeF{sub 3} and CeF{sub 3}:Tb nanoparticles are shown to protect living cells against the vesicular stomatitis virus.

  2. Removal of fluoride from fluoride-bering cerium sulfate solution by hydrous zirconium oxide

    Directory of Open Access Journals (Sweden)

    J. G. He

    2014-04-01

    Full Text Available In this paper the removal of fluoride from fluoride-bearing cerium sulfate solution by amorphous hydrous zirconium oxide was studied. The FTIR, SEM, EDS and UV-vis spectra show that fluoride is successfully adsorbed on hydrous zirconium oxide, and cerium exists as Ce4+ in solution. The study indicates that it is feasible to separate fluorine and cerium from fluorine-bearing rare earth sulfate solution using hydrous zirconium oxide, and eliminate the influence of fluoride on the extraction separation of rare earths.

  3. The effect of cerium valence states at cerium oxide nanoparticle surfaces on cell proliferation

    KAUST Repository

    Naganuma, Tamaki

    2014-05-01

    Understanding and controlling cell proliferation on biomaterial surfaces is critical for scaffold/artificial-niche design in tissue engineering. The mechanism by which underlying integrin ligates with functionalized biomaterials to induce cell proliferation is still not completely understood. In this study, poly-l-lactide (PL) scaffold surfaces were functionalized using layers of cerium oxide nanoparticles (CNPs), which have recently attracted attention for use in therapeutic application due to their catalytic ability of Ce4+ and Ce3+ sites. To isolate the influence of Ce valance states of CNPs on cell proliferation, human mesenchymal stem cells (hMSCs) and osteoblast-like cells (MG63) were cultured on the PL/CNP surfaces with dominant Ce4+ and Ce3+ regions. Despite cell type (hMSCs and MG63 cells), different surface features of Ce4+ and Ce3+ regions clearly promoted and inhibited cell spreading, migration and adhesion behavior, resulting in rapid and slow cell proliferation, respectively. Cell proliferation results of various modified CNPs with different surface charge and hydrophobicity/hydrophilicity, indicate that Ce valence states closely correlated with the specific cell morphologies and cell-material interactions that trigger cell proliferation. This finding suggests that the cell-material interactions, which influence cell proliferation, may be controlled by introduction of metal elements with different valence states onto the biomaterial surface. © 2014 Elsevier Ltd.

  4. Geometry of electromechanically active structures in Gadolinium - doped Cerium oxides

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yuanyuan; Zacharowicz, Renee; Frenkel, Anatoly I., E-mail: igor.lubomirsky@weizmann.ac.il, E-mail: anatoly.frenkel@yu.edu [Physics Department, Yeshiva University, 245 Lexington Avenue, New York, New York 10016 (United States); Kraynis, Olga; Lubomirsky, Igor, E-mail: igor.lubomirsky@weizmann.ac.il, E-mail: anatoly.frenkel@yu.edu [Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100 (Israel); Kas, Joshua [Department of Physics, University of Washington, Seattle, Washington 98195 (United States); Weng, Tsu-Chien; Sokaras, Dimosthenis [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

    2016-05-15

    Local distortions from average structure are important in many functional materials, such as electrostrictors or piezoelectrics, and contain clues about their mechanism of work. However, the geometric attributes of these distortions are exceedingly difficult to measure, leading to a gap in knowledge regarding their roles in electromechanical response. This task is particularly challenging in the case of recently reported non-classical electrostriction in Cerium-Gadolinium oxides (CGO), where only a small population of Ce-O bonds that are located near oxygen ion vacancies responds to external electric field. We used high-energy resolution fluorescence detection (HERFD) technique to collect X-ray absorption spectra in CGO in situ, with and without an external electric field, coupled with theoretical modeling to characterize three-dimensional geometry of electromechanically active units.

  5. Effect of Surface Modification on Behaviors of Cerium Oxide Nanopowders

    Institute of Scientific and Technical Information of China (English)

    Li Mei; Shi Zhenxue; Liu Zhaogang; Hu Yanhong; Wang Mitang; Li Hangquan

    2007-01-01

    Study was made on the effect of surface modification on the behaviors of cerium oxide nanopowders. A surfactant-sodium dodecyl sulfate(C12H25SO4Na) was used to modify the surface of CeO2 powder particles. The unmodified and modified CeO2 powders were characterized by using a powder comprehensive characteristic tester, laser particle size analyzer, specific surface area tester, X-ray diffraction tester, and a scanning electron microscope. The testing and analysis results showed that C12H25SO4Na surface modification might increase the flowability and dispersity, and decrease the specific surface area and agglomeration of CeO2 powders. The mechanism of the surface modification of CeO2 powder particles was also discussed.

  6. Study on Catalysts with Rhodium Loading on Different Cerium-Zirconium Mixed Oxides

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The catalysts with Rh loading on different cerium-zirconium mixed oxides were characterized by BET, H2-TPR and OSC. The effects of different cerium-zirconium mixed oxides on catalytic performance and thermal stability of Rh loaded catalyst were studied. The results show that: (1) Rh can enhance cerium-zirconium mixed oxides OSC and catalytic reaction rates; (2) cerium-zirconium mixed oxides with high Ce contents and low Zr contents are more favorable to the stability of catalysts. Moreover, the contents of CeO2 have important effect on catalysts characteristics, and the addition of some rare earth components, such as La, Pr and Nd also have some influences.

  7. The properties of protective oxide scales containing cerium on alloy 800H in oxidizing and oxidizing/sulphidizing environments

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Fransen, T.; Geerdink, B.; Gellings, P.J.; Stroosnijder, M.F.

    1991-01-01

    The corrosion protection of oxide scales formed by electrophoretic deposition in a cerium-containing sol on Alloy 800H, a 32Ni-20Cr steel, followed by firing in air at 1123 K was studied in oxidizing and mixed oxidizing/sulphidizing environments at elevated temperatures. In particular, the influence

  8. Effects of uncoated and citric acid coated cerium oxide nanoparticles, bulk cerium oxide, cerium acetate, and citric acid on tomato plants.

    Science.gov (United States)

    Barrios, Ana Cecilia; Rico, Cyren M; Trujillo-Reyes, Jesica; Medina-Velo, Illya A; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L

    2016-09-01

    Little is known about the physiological and biochemical responses of plants exposed to surface modified nanomaterials. In this study, tomato (Solanum lycopersicum L.) plants were cultivated for 210days in potting soil amended with uncoated and citric acid coated cerium oxide nanoparticles (nCeO2, CA+nCeO2) bulk cerium oxide (bCeO2), and cerium acetate (CeAc). Millipore water (MPW), and citric acid (CA) were used as controls. Physiological and biochemical parameters were measured. At 500mg/kg, both the uncoated and CA+nCeO2 increased shoot length by ~9 and ~13%, respectively, while bCeO2 and CeAc decreased shoot length by ~48 and ~26%, respectively, compared with MPW (p≤0.05). Total chlorophyll, chlo-a, and chlo-b were significantly increased by CA+nCeO2 at 250mg/kg, but reduced by bCeO2 at 62.5mg/kg, compared with MPW. At 250 and 500mg/kg, nCeO2 increased Ce in roots by 10 and 7 times, compared to CA+nCeO2, but none of the treatments affected the Ce concentration in above ground tissues. Neither nCeO2 nor CA+nCeO2 affected the homeostasis of nutrient elements in roots, stems, and leaves or catalase and ascorbate peroxidase in leaves. CeAc at 62.5 and 125mg/kg increased B (81%) and Fe (174%) in roots, while at 250 and 500mg/kg, increased Ca in stems (84% and 86%, respectively). On the other hand, bCeO2 at 62.5 increased Zn (152%) but reduced P (80%) in stems. Only nCeO2 at 62.5mg/kg produced higher total number of tomatoes, compared with control and the rest of the treatments. The surface coating reduced Ce uptake by roots but did not affect its translocation to the aboveground organs. In addition, there was no clear effect of surface coating on fruit production. To our knowledge, this is the first study comparing the effects of coated and uncoated nCeO2 on tomato plants. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Thermal Treatment of Cerium Oxide and Its Properties: Adsorption Ability versus Degradation Efficiency

    Directory of Open Access Journals (Sweden)

    Pavel Janoš

    2014-01-01

    Full Text Available Cerium oxide belongs to the most important heterogeneous catalysts, but its applicability as so-called reactive sorbent for the degradation of toxic chemicals was only recently discovered. For these purposes, cerium oxide is prepared by precipitation of insoluble cerium salts (carbonates with a subsequent thermal decomposition. Properties of cerium oxide prepared from the carbonate precursor are strongly affected by the temperature during the calcination. Main physicochemical properties of cerium oxide (specific surface area, crystallinity, and surface chemistry were examined in dependence on the calcination temperature. As the adsorptive properties of CeO2 are undoubtedly of great importance in the abovementioned applications, the adsorption ability was studied using an azo dye Acid Orange 7 (AO7 as a model compound. The highest sorption efficiency towards AO7 exhibited sorbents prepared at temperatures below 700°C, which was attributed mainly to the presence of hydroxyl groups on the oxide surface. A strong correlation was found between an adsorption efficiency of cerium oxides and their degradation efficiency for organophosphate pesticide parathion methyl. The >Ce–OH groups on the sorbent surface are responsible for the dye binding by the surface-complexation mechanism, and probably also for the nucleophilic cleavage of the P–O–aryl bond in the pesticide molecule.

  10. Synthesis of cerium oxide (CeO{sub 2}) nanoparticles using simple CO-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Farahmandjou, M.; Zarinkamar, M.; Firoozabadi, T. P., E-mail: farahamndjou@iauvaramin.ac.ir [Islamis Azad University, Varamin-Phisva Branch, Department of Physics, Varamin (Iran, Islamic Republic of)

    2016-11-01

    Synthesis of cerium oxide (CeO{sub 2}) nanoparticles was studied by new and simple co-precipitation method. The cerium oxide nanoparticles were synthesized using cerium nitrate and potassium carbonate precursors. Their physicochemical properties were characterized by high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (Sem), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (Ftir) and UV-Vis spectrophotometer. XRD pattern showed the cubic structure of the cerium oxide nanoparticles. The average particle size of CeO{sub 2} was around 20 nm as estimated by XRD technique and direct HRTEM observations. The surface morphological studies from Sem and Tem depicted spherical particles with formation of clusters. The sharp peaks in Ftir spectrum determined the existence of CeO{sub 2} stretching mode and the absorbance peak of UV-Vis spectrum showed the bandgap energy of 3.26 eV. (Author)

  11. Kinetic study of diesel soot oxidation: application to simulation of diesel particulate filter regeneration; Etude cinetique de la combustion des suies diesel: application a la modelisation de la regeneration du filtre a particule

    Energy Technology Data Exchange (ETDEWEB)

    Huguet, Ch.

    2005-11-15

    Because of their toxicity, soot are considered as the most important pollutant from Diesel engines. The Diesel Particulate Filter (DPF) is widely deployed in Europe to address the significant reductions in particulate emissions required by increasingly stringent emission standards, both for heavy duty vehicles and passenger cars. Such a DPF filtrates above 99% of soot emissions and must be regularly regenerated. The use of additive allows to decrease the soot oxidation temperature to values which can be reached by appropriate engine tuning. The soot addition is a dominant parameter for the development of regeneration strategies. Its influence must be correctly represented by models. This Ph-D was performed at IFP in collaboration with ADEME and was supported by the LCSR at Orleans. The aim of the present research is to develop a kinetic mechanism characteristic of Diesel soot oxidation, which can be integrated into a DPF regeneration model and used for engine control. The oxidation study was based on soot characterisation and reaction kinetics investigations. The samples of Diesel soot were collected, without and with Cerium/Iron additive, by using two engines points representative of two normalized European cycles (ECE and EUDC). Thermal and composition analyses with techniques such as XPS, XRD or TEM were used to determine their physical and chemical properties. Their oxidation kinetics was experimentally studied on a synthetic gas bench (SGB) with a fixed bed reactor. Different tests were performed: temperature-programmed oxidation (TPO), Isothermal oxidation (IO), and sequential oxidation. The results allowed to correlate Diesel soot physical and chemical properties with their oxidation rate. A kinetic model was developed, which is based on global carbon consummation law and distinguishes the oxidation of different soot components. The simulation results agree very well with the experimental results of Diesel soot oxidation. (author)

  12. Effects of amorphous silica coating on cerium oxide nanoparticles induced pulmonary responses

    Science.gov (United States)

    Ma, Jane; Mercer, Robert R.; Barger, Mark; Schwegler-Berry, Diane; Cohen, Joel M.; Demokritou, Philip; Castranova, Vincent

    2015-01-01

    Recently cerium compounds have been used in a variety of consumer products, including diesel fuel additives, to increase fuel combustion efficiency and decrease diesel soot emissions. However, cerium oxide (CeO2) nanoparticles have been detected in the exhaust, which raises a health concern. Previous studies have shown that exposure of rats to nanoscale CeO2 by intratracheal instillation (IT) induces sustained pulmonary inflammation and fibrosis. In the present study, male Sprague–Dawley rats were exposed to CeO2 or CeO2 coated with a nano layer of amorphous SiO2 (aSiO2/CeO2) by a single IT and sacrificed at various times post-exposure to assess potential protective effects of the aSiO2 coating. The first acellular bronchoalveolar lavage (BAL) fluid and BAL cells were collected and analyzed from all exposed animals. At the low dose (0.15 mg/kg), CeO2 but not aSiO2/CeO2 exposure induced inflammation. However, at the higher doses, both particles induced a dose-related inflammation, cytotoxicity, inflammatory cytokines, matrix metalloproteinase (MMP)-9, and tissue inhibitor of MMP at 1 day post-exposure. Morphological analysis of lung showed an increased inflammation, surfactant and collagen fibers after CeO2 (high dose at 3.5 mg/kg) treatment at 28 days post-exposure. aSiO2 coating significantly reduced CeO2-induced inflammatory responses in the airspace and appeared to attenuate phospholipidosis and fibrosis. Energy dispersive X-ray spectroscopy analysis showed Ce and phosphorous (P) in all particle-exposed lungs, whereas Si was only detected in aSiO2/CeO2-exposed lungs up to 3 days after exposure, suggesting that aSiO2 dissolved off the CeO2 core, and some of the CeO2 was transformed to CePO4 with time. These results demonstrate that aSiO2 coating reduce CeO2-induced inflammation, phospholipidosis and fibrosis. PMID:26210349

  13. Antioxidant Cerium Oxide Nanoparticles in Biology and Medicine.

    Science.gov (United States)

    Nelson, Bryant C; Johnson, Monique E; Walker, Marlon L; Riley, Kathryn R; Sims, Christopher M

    2016-05-17

    Previously, catalytic cerium oxide nanoparticles (CNPs, nanoceria, CeO2-x NPs) have been widely utilized for chemical mechanical planarization in the semiconductor industry and for reducing harmful emissions and improving fuel combustion efficiency in the automobile industry. Researchers are now harnessing the catalytic repertoire of CNPs to develop potential new treatment modalities for both oxidative- and nitrosative-stress induced disorders and diseases. In order to reach the point where our experimental understanding of the antioxidant activity of CNPs can be translated into useful therapeutics in the clinic, it is necessary to evaluate the most current evidence that supports CNP antioxidant activity in biological systems. Accordingly, the aims of this review are three-fold: (1) To describe the putative reaction mechanisms and physicochemical surface properties that enable CNPs to both scavenge reactive oxygen species (ROS) and to act as antioxidant enzyme-like mimetics in solution; (2) To provide an overview, with commentary, regarding the most robust design and synthesis pathways for preparing CNPs with catalytic antioxidant activity; (3) To provide the reader with the most up-to-date in vitro and in vivo experimental evidence supporting the ROS-scavenging potential of CNPs in biology and medicine.

  14. Antioxidant Cerium Oxide Nanoparticles in Biology and Medicine

    Directory of Open Access Journals (Sweden)

    Bryant C. Nelson

    2016-05-01

    Full Text Available Previously, catalytic cerium oxide nanoparticles (CNPs, nanoceria, CeO2-x NPs have been widely utilized for chemical mechanical planarization in the semiconductor industry and for reducing harmful emissions and improving fuel combustion efficiency in the automobile industry. Researchers are now harnessing the catalytic repertoire of CNPs to develop potential new treatment modalities for both oxidative- and nitrosative-stress induced disorders and diseases. In order to reach the point where our experimental understanding of the antioxidant activity of CNPs can be translated into useful therapeutics in the clinic, it is necessary to evaluate the most current evidence that supports CNP antioxidant activity in biological systems. Accordingly, the aims of this review are three-fold: (1 To describe the putative reaction mechanisms and physicochemical surface properties that enable CNPs to both scavenge reactive oxygen species (ROS and to act as antioxidant enzyme-like mimetics in solution; (2 To provide an overview, with commentary, regarding the most robust design and synthesis pathways for preparing CNPs with catalytic antioxidant activity; (3 To provide the reader with the most up-to-date in vitro and in vivo experimental evidence supporting the ROS-scavenging potential of CNPs in biology and medicine.

  15. Samarium Doped Cerium Oxide Clusters: a Study on the Modulation of Electronic Structure

    Science.gov (United States)

    Topolski, Josey E.; Kafader, Jared O.; Marrero-Colon, Vicmarie; Chick Jarrold, Caroline

    2017-06-01

    Cerium oxide is known for its use in solid oxide fuel cells due to its high ionic conductivity. The doping of trivalent samarium atoms into cerium oxide is known to enhance the ionic conductivity through the generation of additional oxygen vacancies. This study probes the electronic structure of Sm_{x}Ce_{y}O_{z} (x+y=3, z=2-4) anion and neutral clusters. Anion photoelectron spectra of these mixed metal clusters exhibit additional spectral features not present in the previously studied cerium oxide clusters. Density functional theory calculations have been used to aid interpretation of collected spectra. The results of this work can be used to inform the design of materials used for solid oxide fuel cells.

  16. Catalytic properties and biomedical applications of cerium oxide nanoparticles

    KAUST Repository

    Walkey, Carl D.

    2014-11-10

    Cerium oxide nanoparticles (nanoceria) have shown promise as catalytic antioxidants in the test tube, cell culture models and animal models of disease. However given the reactivity that is well established at the surface of these nanoparticles, the biological utilization of nanoceria as a therapeutic still poses many challenges. Moreover the form that these particles take in a biological environment, such as the changes that can occur due to a protein corona, are not well established. This review aims to summarize the existing literature on biological use of nanoceria, and to raise questions about what further study is needed to apply this interesting catalytic material to biomedical applications. These questions include: 1) How does preparation, exposure dose, route and experimental model influence the reported effects of nanoceria in animal studies? 2) What are the considerations to develop nanoceria as a therapeutic agent in regards to these parameters? 3) What biological targets of reactive oxygen species (ROS) and reactive nitrogen species (RNS) are relevant to this targeting, and how do these properties also influence the safety of these nanomaterials?

  17. Anti-angiogenic activity of heparin functionalised cerium oxide nanoparticles.

    Science.gov (United States)

    Lord, Megan S; Tsoi, Bonny; Gunawan, Cindy; Teoh, Wey Yang; Amal, Rose; Whitelock, John M

    2013-11-01

    Cerium oxide nanoparticles (nanoceria) are widely reported to be non-cytotoxic and modulate intracellular reactive oxygen species (ROS). In this study, nanoceria (dxRD = 12 nm) were functionalised with either 130 or 880 molecules of unfractionated heparin using the organosilane linker, 3-aminopropyltriethoxysilane. Nanoceria with a low level of heparin functionalisation were found to scavenge intracellular ROS to the same extent as unfunctionalised nanoceria and significantly more than cells exposed to medium only. In contrast, nanoceria with the highest level of heparin functionalisation were not as effective at scavenging intracellular ROS. Nanoceria were localised predominantly in the cytoplasm, while heparin-nanoceria were localised in both the cytoplasm and lysosomes. Together these data demonstrated that the level of nanoceria surface functionalisation with heparin determined the intracellular localisation and ROS scavenging ability of these particles. Additionally, heparin-nanoceria were effective in reducing endothelial cell proliferation indicating that they may find application in the control of angiogenesis in cancer in the future.

  18. Surface modification of promising cerium oxide nanoparticles for nanomedicine applications

    KAUST Repository

    Nanda, Himansu Sekhar

    2016-11-14

    Cerium oxide nanoparticles (CNPs) or nanoceria have emerged as a potential nanomedicine for the treatment of several diseases such as cancer. CNPs have a natural tendency to aggregate or agglomerate in their bare state, which leads to sedimentation in a biological environment. Since the natural biological environment is essentially aqueous, nanoparticle surface modification using suitable biocompatible hydrophilic chemical moieties is highly desirable to create effective aqueous dispersions. In this report, (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl)triethoxysilane was used as a functional, biocompatible organosilane to modify the surface of CNPs to produce promising nanoparticles which open substantial therapeutic avenues. The surface modified nanoparticles were produced in situ via an ammonia-induced ethylene glycol-assisted precipitation method and were characterized using complimentary characterization techniques. The interaction between the functional moiety and the nanoparticle was studied using powerful cross polarization/magic angle sample spinning solid state nuclear magnetic resonance spectroscopy. The surface-modified nanoparticles were extremely small and demonstrated a significant improvement in aqueous dispersibility. Moreover, the existence of a strong ionic coordination between the functional moiety and the surface of the nanoparticle was realised, indicating that the surface modified nanoceria are stable and that the nanoparticles should demonstrate an enhanced circulation time in a biological environment. The surface modification approach should be promising for the production of CNPs for nanomedicine applications. © The Royal Society of Chemistry.

  19. Effects of uncoated and citric acid coated cerium oxide nanoparticles, bulk cerium oxide, cerium acetate, and citric acid on tomato plants

    Energy Technology Data Exchange (ETDEWEB)

    Barrios, Ana Cecilia [Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); Rico, Cyren M. [Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); Trujillo-Reyes, Jesica [Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); Medina-Velo, Illya A. [Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); Peralta-Videa, Jose R. [Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); Environmental Science and Engineering Ph.D. Program, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); Gardea-Torresdey, Jorge L., E-mail: jgardea@utep.edu [Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); Environmental Science and Engineering Ph.D. Program, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States)

    2016-09-01

    Little is known about the physiological and biochemical responses of plants exposed to surface modified nanomaterials. In this study, tomato (Solanum lycopersicum L.) plants were cultivated for 210 days in potting soil amended with uncoated and citric acid coated cerium oxide nanoparticles (nCeO{sub 2}, CA + nCeO{sub 2}) bulk cerium oxide (bCeO{sub 2}), and cerium acetate (CeAc). Millipore water (MPW), and citric acid (CA) were used as controls. Physiological and biochemical parameters were measured. At 500 mg/kg, both the uncoated and CA + nCeO{sub 2} increased shoot length by ~ 9 and ~ 13%, respectively, while bCeO{sub 2} and CeAc decreased shoot length by ~ 48 and ~ 26%, respectively, compared with MPW (p ≤ 0.05). Total chlorophyll, chlo-a, and chlo-b were significantly increased by CA + nCeO{sub 2} at 250 mg/kg, but reduced by bCeO{sub 2} at 62.5 mg/kg, compared with MPW. At 250 and 500 mg/kg, nCeO{sub 2} increased Ce in roots by 10 and 7 times, compared to CA + nCeO{sub 2}, but none of the treatments affected the Ce concentration in above ground tissues. Neither nCeO{sub 2} nor CA + nCeO{sub 2} affected the homeostasis of nutrient elements in roots, stems, and leaves or catalase and ascorbate peroxidase in leaves. CeAc at 62.5 and 125 mg/kg increased B (81%) and Fe (174%) in roots, while at 250 and 500 mg/kg, increased Ca in stems (84% and 86%, respectively). On the other hand, bCeO{sub 2} at 62.5 increased Zn (152%) but reduced P (80%) in stems. Only nCeO{sub 2} at 62.5 mg/kg produced higher total number of tomatoes, compared with control and the rest of the treatments. The surface coating reduced Ce uptake by roots but did not affect its translocation to the aboveground organs. In addition, there was no clear effect of surface coating on fruit production. To our knowledge, this is the first study comparing the effects of coated and uncoated nCeO{sub 2} on tomato plants. - Highlights: • At 500 mg/kg, coated and bare NPs increased stem length by 13 and 9

  20. Effects of precipitate aging time on the cerium-zirconium composite oxides

    Institute of Scientific and Technical Information of China (English)

    钟强; 崔梅生; 岳梅; 王琦; 王磊; 郭荣贵; 龙志奇; 黄小卫

    2014-01-01

    Cerium-zirconium composite oxides with high performance were synthesized by a co-precipitation method, using zirco-nium oxychloride and rare earth chloride as raw materials. The effects of precipitate aging time on the properties of cerium-zirconium composite oxides were investigated. The prepared cerium-zirconium composite oxides were characterized by X-ray diffraction (XRD), BET specific surface area, pulsed oxygen chemical adsorption, H2 temperature-programmed-reduction (H2-TPR), scanning electron microscopy (SEM), etc. The results showed that the precipitate aging time caused great effects on the properties of cerium zirconium composite oxides. With the increase of aging time, the cerium zirconium composite oxides showed enhanced specific sur-face area, good thermal stability, and high oxygen storage capacity (OSC). The best performance sample was obtained while the pre-cipitate aging time up to 48 h, with the specific surface area of 140.7 m2/g, and OSC of 657.24μmolO2/g for the fresh sample. Even after thermal aged under 1000 ºC for 4 h, the aged specific surface area was 41.6 m2/g, moreover with a good OSC of 569.9μmolO2/g.

  1. Variations in Reactivity on Different Crystallographic Orientations of Cerium Oxide

    Energy Technology Data Exchange (ETDEWEB)

    Mullins, David R [ORNL; Albrecht, Peter M [ORNL; Calaza, Florencia C [ORNL

    2013-01-01

    Cerium oxide is a principal component in many heterogeneous catalytic processes. One of its key characteristics is the ability to provide or remove oxygen in chemical reactions. The different crystallographic faces of ceria present significantly different surface structures and compositions that may alter the catalytic reactivity. The structure and composition determine the number of coordination vacancies surrounding surface atoms, the availability of adsorption sites, the spacing between adsorption sites and the ability to remove O from the surface. To investigate the role of surface orientation on reactivity, CeO2 films were grown with two different orientations. CeO2(100) films were grown ex situ by pulsed laser deposition on Nb-doped SrTiO3(100). CeO2(111) films were grown in situ by thermal deposition of Ce metal onto Ru(0001) in an oxygen atmosphere. The chemical reactivity was characterized by the adsorption and decomposition of various molecules such as alcohols, aldehydes and organic acids. In general the CeO2(100) surface was found to be more active, i.e. molecules adsorbed more readily and reacted to form new products, especially on a fully oxidized substrate. However the CeO2(100) surface was less selective with a greater propensity to produce CO, CO2 and water as products. The differences in chemical reactivity are discussed in light of possible structural terminations of the two surfaces. Recently nanocubes and nano-octahedra have been synthesized that display CeO2(100) and CeO2(111) faces, respectively. These nanoparticles enable us to correlate reactions on high surface area model catalysts at atmospheric pressure with model single crystal films in a UHV environment.

  2. A corrosion resistant cerium oxide based coating on aluminum alloy 2024 prepared by brush plating

    Energy Technology Data Exchange (ETDEWEB)

    Tang Junlei; Han Zhongzhi [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Zuo Yu, E-mail: zuoy@mail.buct.edu.cn [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Tang Yuming [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2011-01-15

    Cerium oxide based coatings were prepared on AA2024 Al alloy by brush plating. The characteristic of this technology is that hydrogen peroxide, which usually causes the plating solution to be unstable, is not necessary in the plating electrolyte. The coating showed laminated structures and good adhesive strength with the substrate. X-ray diffraction and X-ray photoelectron spectroscopy analysis showed that the coatings were composed of Ce(III) and Ce(IV) oxides. The brush plated coatings on Al alloys improved corrosion resistance. The influence of plating parameters on structure and corrosion resistance of the cerium oxide based coating was studied.

  3. Soil organic matter influences cerium translocation and physiological processes in kidney bean plants exposed to cerium oxide nanoparticles.

    Science.gov (United States)

    Majumdar, Sanghamitra; Peralta-Videa, Jose R; Trujillo-Reyes, Jesica; Sun, Youping; Barrios, Ana C; Niu, Genhua; Margez, Juan P Flores-; Gardea-Torresdey, Jorge L

    2016-11-01

    Soil organic matter plays a major role in determining the fate of the engineered nanomaterials (ENMs) in the soil matrix and effects on the residing plants. In this study, kidney bean plants were grown in soils varying in organic matter content and amended with 0-500mg/kg cerium oxide nanoparticles (nano-CeO2) under greenhouse condition. After 52days of exposure, cerium accumulation in tissues, plant growth and physiological parameters including photosynthetic pigments (chlorophylls and carotenoids), net photosynthesis rate, transpiration rate, and stomatal conductance were recorded. Additionally, catalase and ascorbate peroxidase activities were measured to evaluate oxidative stress in the tissues. The translocation factor of cerium in the nano-CeO2 exposed plants grown in organic matter enriched soil (OMES) was twice as the plants grown in low organic matter soil (LOMS). Although the leaf cover area increased by 65-111% with increasing nano-CeO2 concentration in LOMS, the effect on the physiological processes were inconsequential. In OMES leaves, exposure to 62.5-250mg/kg nano-CeO2 led to an enhancement in the transpiration rate and stomatal conductance, but to a simultaneous decrease in carotenoid contents by 25-28%. Chlorophyll a in the OMES leaves also decreased by 27 and 18% on exposure to 125 and 250mg/kg nano-CeO2. In addition, catalase activity increased in LOMS stems, and ascorbate peroxidase increased in OMES leaves of nano-CeO2 exposed plants, with respect to control. Thus, this study provides clear evidence that the properties of the complex soil matrix play decisive roles in determining the fate, bioavailability, and biological transport of ENMs in the environment. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Mesoporous cerium oxide nanospheres for the visible-light driven photocatalytic degradation of dyes

    Directory of Open Access Journals (Sweden)

    Subas K. Muduli

    2014-04-01

    Full Text Available A facile, solvothermal synthesis of mesoporous cerium oxide nanospheres is reported for the purpose of the photocatalytic degradation of organic dyes and future applications in sustainable energy research. The earth-abundant, relatively affordable, mixed valence cerium oxide sample, which consists of predominantly Ce7O12, has been characterized by powder X-ray diffraction, X-ray photoelectron and UV–vis spectroscopy, and transmission electron microscopy. Together with N2 sorption experiments, the data confirms that the new cerium oxide material is mesoporous and absorbs visible light. The photocatalytic degradation of rhodamin B is investigated with a series of radical scavengers, suggesting that the mechanism of photocatalytic activity under visible-light irradiation involves predominantly hydroxyl radicals as the active species.

  5. Structure, Morphology and Reducibility of Epitaxial Cerium Oxide Ultrathin Films and Nanostructures

    Directory of Open Access Journals (Sweden)

    Paola Luches

    2015-08-01

    Full Text Available Cerium oxide is a very interesting material that finds applications in many different fields, such as catalysis, energy conversion, and biomedicine. An interesting approach to unravel the complexity of real systems and obtain an improved understanding of cerium oxide-based materials is represented by the study of model systems in the form of epitaxial ultrathin films or nanostructures supported on single crystalline substrates. These materials often show interesting novel properties, induced by spatial confinement and by the interaction with the supporting substrate, and their understanding requires the use of advanced experimental techniques combined with computational modeling. Recent experimental and theoretical studies performed within this field are examined and discussed here, with emphasis on the new perspectives introduced in view of the optimization of cerium oxide-based materials for application in different fields.

  6. Experimental Investigations on the Effects of Cerium Oxide Nanoparticle Fuel Additives on Biodiesel

    Directory of Open Access Journals (Sweden)

    V. Sajith

    2010-01-01

    Full Text Available This paper reports the results of experimental investigations on the influence of the addition of cerium oxide in the nanoparticle form on the major physicochemical properties and the performance of biodiesel. The physicochemical properties of the base fuel and the modified fuel formed by dispersing the catalyst nanoparticles by ultrasonic agitation are measured using ASTM standard test methods. The effects of the additive nanoparticles on the individual fuel properties, the engine performance, and emissions are studied, and the dosing level of the additive is optimized. Comparisons of the performance of the fuel with and without the additive are also presented. The flash point and the viscosity of biodiesel were found to increase with the inclusion of the cerium oxide nanoparticles. The emission levels of hydrocarbon and NOx are appreciably reduced with the addition of cerium oxide nanoparticles.

  7. Gas sensing behaviour of cerium oxide and magnesium aluminate composites

    Indian Academy of Sciences (India)

    N NITHYAVATHY; V RAJENDRAN; L JOHN BERCHMANS; M MAAZA; S KRITHIKA; S ARUNMETHA

    2017-08-01

    Composites of cerium oxide (CeO$_2$) and magnesium aluminate (MgAl$_2$O$_4$) were prepared by the moltensalt synthesis (MSS) method at 1130 K. The composite samples were named as MA, MAC0.07 and MAC0.14 (at CeO$_2$:0, 0.07 and 0.14 g in MgAl$_2$O$_4$, respectively) and these were characterized by X-ray diffraction and energy-dispersiveX-ray analyses. It is seen that the microstructure of the composite samples are quite similar except for a small increasein particle size. The energy-dispersive X-ray analyses provide the presence of concentration of Ce, Mg, Al and O in thecomposite. Scanning electron microscope, coupled with energy-dispersive X-ray analysis (SEM-EDAX) was used to identifythe morphology, microstructure and elemental composition of the prepared samples. The decomposition and dissociationreactions of the precursors were determined using differential thermal and thermogravimetric analysis (TGA). A lone pairof the electron state was identified from the electro paramagnetic resonance spectrum. An optical energy band gap of 3.3 eV was calculated from the UV–Vis absorbance spectra. The gas response to changes in oxygen (O$_2$), carbon monoxide (CO) (at 0.5, 1.0 and 1.5 bar) and ethanol (at 50 and 100 ppm) was quantitatively analysed in all the samples at differentoperating temperatures (300-500 K). The magnitude of the temperature varied linearly regardless of the gas pressure insidethe chamber, by increasing the supply in the heating pad, mounted below the sensor sample. The composite samples indicatea good response to different gases with detection of the smallest change in gas pressure.

  8. Effects of Cerium Oxide Nanoparticles on Sorghum Plant Traits

    Science.gov (United States)

    Mu, L.; Chen, Y.; Darnault, C. J. G.; Rauh, B.; Kresovich, S.; Korte, C.

    2015-12-01

    Nanotechnology and nanomaterials are considered as the development of the modern science. However, besides with that wide application, nanoparticles arouse to the side effects on the environment and human health. As the catalyst of ceramics and fuel industry, Cerium (IV) oxide nanoparticles (CeO2 NPs) can be found in the environment following their use and life-cycle. Therefore, it is critical to assess the potential effects that CeO2 NPs found in soils may have on plants. In this study, CeO2 NPs were analyzed for the potential influence on the sorghum [Sorghum bicolor (L.) Moench] (Reg. no. 126) (PI 154844) growth and traits. The objectives of this research were to determine whether CeO2 NPs impact the sorghum germination and growth characteristics. The sorghum was grown in the greenhouse located at Biosystems Research Complex, Clemson University under different CeO2 NPs treatments (0mg; 100mg; 500mg; 1000mg CeO2 NPs/Kg soil) and harvested around each month. At the end of the each growing period, above ground vegetative tissue was air-dried, ground to 2mm particle size and compositional traits estimated using near-infrared spectroscopy. Also, the NPK value of the sorghum tissue was tested by Clemson Agriculture Center. After the first harvest, the result showed that the height of above ground biomass under the nanoparticles stress was higher than that of control group. This difference between the control and the nanoparticles treatments was significant (F>F0.05; LSD). Our results also indicated that some of the compositional traits were impacted by the different treatments, including the presence and/or concentrations of the nanoparticles.

  9. Environmental Geochemistry of Cerium: Applications and Toxicology of Cerium Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Jessica T. Dahle

    2015-01-01

    Full Text Available Cerium is the most abundant of rare-earth metals found in the Earth’s crust. Several Ce-carbonate, -phosphate, -silicate, and -(hydroxide minerals have been historically mined and processed for pharmaceutical uses and industrial applications. Of all Ce minerals, cerium dioxide has received much attention in the global nanotechnology market due to their useful applications for catalysts, fuel cells, and fuel additives. A recent mass flow modeling study predicted that a major source of CeO2 nanoparticles from industrial processing plants (e.g., electronics and optics manufactures is likely to reach the terrestrial environment such as landfills and soils. The environmental fate of CeO2 nanoparticles is highly dependent on its physcochemical properties in low temperature geochemical environment. Though there are needs in improving the analytical method in detecting/quantifying CeO2 nanoparticles in different environmental media, it is clear that aquatic and terrestrial organisms have been exposed to CeO2 NPs, potentially yielding in negative impact on human and ecosystem health. Interestingly, there has been contradicting reports about the toxicological effects of CeO2 nanoparticles, acting as either an antioxidant or reactive oxygen species production-inducing agent. This poses a challenge in future regulations for the CeO2 nanoparticle application and the risk assessment in the environment.

  10. Evaluation of Antiproliferative Potential of Cerium Oxide Nanoparticles on HeLa Human Cervical Tumor Cell

    Directory of Open Access Journals (Sweden)

    Zoriţa Diaconeasa

    2015-05-01

    Full Text Available Cerium oxide nanoparticles (CeO2 nanoparticles as nanomaterials have promising biomedical applications. In this paper, the cytotoxicity induced by CONPs human cervical tumor cells was investigated. Cerium oxide nanoparticles were synthesized using the precipitation method. The nanoparticles were found to inhibit the proliferation of HeLa human cervical tumor cells in a dose dependent manner but did not showed to be cytotoxic as analyzed by MTT assay. The administrated treatment decreased the HeLa cell viability cells from 100% to 65% at the dose of 100 μg/mL.

  11. Cerium Oxide Nanoparticles and Bulk Cerium Oxide Leading to Different Physiological and Biochemical Responses in Brassica rapa.

    Science.gov (United States)

    Ma, Xingmao; Wang, Qiang; Rossi, Lorenzo; Zhang, Weilan

    2016-07-05

    Cerium oxide nanoparticles (CeO2NPs) have been incorporated into many commercial products, and their potential release into the environment through the use and disposal of these products has caused serious concerns. Despite the previous efforts and rapid progress on elucidating the environmental impact of CeO2NPs, the long-term impact of CeO2NPs to plants, a key component of the ecosystem, is still not well understood. The potentially different impact of CeO2NPs and their bulk counterparts to plants is also unclear. The main objectives of this study were (1) to investigate whether continued irrigation with solutions containing different concentrations of CeO2NPs (0, 10, and 100 mg/L) would induce physiological and biochemical adjustments in Brassica rapa in soil growing conditions and (2) to determine whether CeO2NPs and bulk CeO2 particles exert different impacts on plants. The results indicated that bulk CeO2 at 10 and 100 mg/L enhanced plant biomass by 28% and 35%, respectively, while CeO2NPs at equivalent concentrations did not. While the bulk CeO2 treatment resulted in significantly higher concentrations of hydrogen peroxide (H2O2) in plant tissues at the vegetative stage, CeO2NPs led to significantly higher H2O2 levels in plant tissues at the floral stage. The activity of superoxide dismutase (SOD) in Brassica rapa also displayed a growth-stage dependent response to different sizes of CeO2 while catalase (CAT) activity was not affected by either size of CeO2 throughout the life cycle of Brassica rapa. Altogether, the results demonstrated that plant responses to CeO2 exposure varied with the particle sizes and the growth stages of plants.

  12. Oxochloroalkoxide of the Cerium (IV and Titanium (IV as oxides precursor

    Directory of Open Access Journals (Sweden)

    Machado Luiz Carlos

    2002-01-01

    Full Text Available The Cerium (IV and Titanium (IV oxides mixture (CeO2-3TiO2 was prepared by thermal treatment of the oxochloroisopropoxide of Cerium (IV and Titanium (IV. The chemical route utilizing the Cerium (III chloride alcoholic complex and Titanium (IV isopropoxide is presented. The compound Ce5Ti15Cl16O30 (iOPr4(OH-Et15 was characterized by elemental analysis, FTIR and TG/DTG. The X-ray diffraction patterns of the oxides resulting from the thermal decomposition of the precursor at 1000 degreesC for 36 h indicated the formation of cubic cerianite (a = 5.417Å and tetragonal rutile (a = 4.592Å and (c = 2.962 Å, with apparent crystallite sizes around 38 and 55nm, respectively.

  13. Phenotypic and genomic responses to titanium dioxide and cerium oxide nanoparticles in Arabidopsis germinants

    Science.gov (United States)

    The effects of exposure to two nanoparticles (NPs) -titanium dioxide (nano-titania) and cerium oxide (nano-ceria) at 500 mg NPs L-1 on gene expression and growth in Arabidopsis thaliana germinants were studied using microarrays and phenotype studies. After 12 days post treatment,...

  14. Characteristics of cerium-gadolinium oxide (CGO) suspensions as a function of dispersant and powder properties

    DEFF Research Database (Denmark)

    Phair, John; Lönnroth, Nadja; Lundberg, Mats;

    2009-01-01

    A series of concentrated suspensions ( = 0.18–0.34) of cerium-gadolinium oxide (CGO) in terpineol were prepared as a function of dispersant, powder surface area and solids concentration. The stability of the suspensions was assessed by rheological measurements including viscosity and oscillatory...

  15. Photocatalytic action of cerium molybdate and iron-titanium oxide hollow nanospheres on Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Kartsonakis, I. A., E-mail: ikartsonakis@ims.demokritos.gr; Kontogiani, P.; Pappas, G. S.; Kordas, G. [NCSR ' DEMOKRITOS' , Sol-Gel Laboratory, Institute of Advanced Materials, Physicochemical Processes, Nanotechnology and Microsystems (Greece)

    2013-06-15

    This study is focused on the production of hollow nanospheres that reveal antibacterial action. Cerium molybdate and iron-titanium oxide hollow nanospheres with a diameter of 175 {+-} 15 and 221 {+-} 10 nm, respectively, were synthesized using emulsion polymerization and the sol-gel process. Their morphology characterization was accomplished using scanning electron microscopy. Their antibacterial action was examined on pure culture of Escherichia coli considering the loss of their viability. Both hollow nanospheres presented photocatalytic action after illumination with blue-black light, but those of cerium molybdate also demonstrated photocatalytic action in the dark. Therefore, the produced nanospheres can be used for antibacterial applications.

  16. Photocatalytic action of cerium molybdate and iron-titanium oxide hollow nanospheres on Escherichia coli

    Science.gov (United States)

    Kartsonakis, I. A.; Kontogiani, P.; Pappas, G. S.; Kordas, G.

    2013-06-01

    This study is focused on the production of hollow nanospheres that reveal antibacterial action. Cerium molybdate and iron-titanium oxide hollow nanospheres with a diameter of 175 ± 15 and 221 ± 10 nm, respectively, were synthesized using emulsion polymerization and the sol-gel process. Their morphology characterization was accomplished using scanning electron microscopy. Their antibacterial action was examined on pure culture of Escherichia coli considering the loss of their viability. Both hollow nanospheres presented photocatalytic action after illumination with blue-black light, but those of cerium molybdate also demonstrated photocatalytic action in the dark. Therefore, the produced nanospheres can be used for antibacterial applications.

  17. KINETIC AND MECHANISTIC STUDY OF OXIDATION OF ATENOLOL BY CERIUM (IV IN SULPHURIC ACIDIC MEDIUM

    Directory of Open Access Journals (Sweden)

    Fadnis G Anand

    2012-03-01

    Full Text Available The kinetics of oxidation of antihypertensive drug, atenolol by cerium (IV in sulphuric acidic medium has been studied spectrophotometrically at 360 nm. The reaction between cerium (IV and atenolol in acidic medium has exhibited 2:1 stoichiometry. The order of the reaction with respect to atenolol has been found to be one. The observed pseudo first order rate constants kobs increased with sulphuric acid and hydrogen ion concentrations where as decreased bisulphate ion concentration indicating the formation bisulphato reactive species of cerium (IV in the present reaction. The thermodynamic parameters have been evaluated from the temperature variation kinetic data. A possible mechanism is proposed which has been validated by derived rate law. An attempt has been made to use rate data for kinetic estimation of atenolol.KEYWORDS:

  18. Reactive removal of 2-chloroethyl ethyl sulfide vapors under visible light irradiation by cerium oxide modified highly porous zirconium (hydr) oxide

    Science.gov (United States)

    Mitchell, Joshua K.; Arcibar-Orozco, Javier A.; Bandosz, Teresa J.

    2016-12-01

    Highly porous cerium oxide modified Zr(OH)4 samples were synthesized using a simple one stage urea precipitation method. The amorphicity level of zirconium hydroxide did not change upon addition of cerium oxide particles. A unique aspect of the cerium oxide-modified materials is the presence of both the oxide (CeO2) and hydroxide (Zr(OH)4) phases resulting in a unique microporous structure of the final material. Extensive characterization using various chemical and physical methods revealed significant differences in the surface features. All synthesized materials were microporous and small additions of cerium oxide affected the surface chemistry. These samples were found as effective catalysts for a decontamination of mustard gas surrogate, 2-chloroethyl ethyl sulfide (CEES). Cerium oxide addition significantly decreased the band gap of zirconium hydroxide. Ethyl vinyl sulfide and 1,2-bis (Ethyl thio) ethane were identified as surface reaction products.

  19. Experimental Investigation of Performance and emission characteristics of Various Nano Particles with Bio-Diesel blend on Di Diesel Engine

    Science.gov (United States)

    Karthik, N.; Goldwin Xavier, X.; Rajasekar, R.; Ganesh Bairavan, P.; Dhanseelan, S.

    2017-05-01

    Present study provides the effect of Zinc Oxide (ZnO) and Cerium Oxide (CeO2) nanoparticles additives on the Performance and emission uniqueness of Jatropha. Jatropha blended fuel is prepared by the emulsification technique with assist of mechanical agitator. Nano particles (Zinc Oxide (ZnO)) and Cerium Oxide (CeO2)) mixed with Jatropha blended fuel in mass fraction (100 ppm) with assist of an ultrasonicator. Experiments were conducted in single cylinder constant speed direct injection diesel engine for various test fuels. Performance results revealed that Brake Thermal Efficiency (BTE) of Jatropha blended Cerium Oxide (B20CE) is 3% and 11% higher than Jatropha blended zinc oxide (B20ZO) and Jatropha blended fuel (B20) and 4% lower than diesel fuel (D100) at full load conditions. Emission result shows that HC and CO emissions of Jatropha blended Cerium Oxide (B20CE) are (6%, 22%, 11% and 6%, 15%, 12%) less compared with Jatropha blended Zinc Oxide (B20ZO), diesel (D100) and Jatropha blended fuel (B20) at full load conditions. NOx emissions of Jatropha blended Cerium Oxide is 1 % higher than diesel fuel (D100) and 2% and 5% lower than Jatropha blended Zinc Oxide, and jatropha blended fuel.

  20. Exposure, Health and Ecological Effects Review of Engineered Nanoscale Cerium and Cerium Oxide Associated with its Use as a Fuel Additive

    Science.gov (United States)

    Advances of nanoscale science have produced nanomaterials with unique physical and chemical properties at commercial levels which are now incorporated into over 1000 products. Nanoscale cerium (di) oxide (CeO(2)) has recently gained a wide range of applications which includes coa...

  1. Investigation of the Carbon Monoxide Gas Sensing Characteristics of Tin Oxide Mixed Cerium Oxide Thin Films

    Directory of Open Access Journals (Sweden)

    Muhammad B. Haider

    2012-02-01

    Full Text Available Thin films of tin oxide mixed cerium oxide were grown on unheated substrates by physical vapor deposition. The films were annealed in air at 500 °C for two hours, and were characterized using X-ray photoelectron spectroscopy, atomic force microscopy and optical spectrophotometry. X-ray photoelectron spectroscopy and atomic force microscopy results reveal that the films were highly porous and porosity of our films was found to be in the range of 11.6–21.7%. The films were investigated for the detection of carbon monoxide, and were found to be highly sensitive. We found that 430 °C was the optimum operating temperature for sensing CO gas at concentrations as low as 5 ppm. Our sensors exhibited fast response and recovery times of 26 s and 30 s, respectively.

  2. Homoleptic cerium(III) and cerium(IV) nitroxide complexes: significant stabilization of the 4+ oxidation state.

    Science.gov (United States)

    Bogart, Justin A; Lewis, Andrew J; Medling, Scott A; Piro, Nicholas A; Carroll, Patrick J; Booth, Corwin H; Schelter, Eric J

    2013-10-07

    Electrochemical experiments performed on the complex Ce(IV)[2-((t)BuNO)py]4, where [2-((t)BuNO)py](-) = N-tert-butyl-N-2-pyridylnitroxide, indicate a 2.51 V stabilization of the 4+ oxidation state of Ce compared to [(n)Bu4N]2[Ce(NO3)6] in acetonitrile and a 2.95 V stabilization compared to the standard potential for the ion under aqueous conditions. Density functional theory calculations suggest that this preference for the higher oxidation state is a result of the tetrakis(nitroxide) ligand framework at the Ce cation, which allows for effective electron donation into, and partial covalent overlap with, vacant 4f orbitals with δ symmetry. The results speak to the behavior of CeO2 and related solid solutions in oxygen uptake and transport applications, in particular an inherent local character of bonding that stabilizes the 4+ oxidation state. The results indicate a cerium(IV) complex that has been stabilized to an unprecedented degree through tuning of its ligand-field environment.

  3. Structure Analysis of Oxidation Film of Ignition-Inhibition AZ91D Ma gnesium Alloy Added with Cerium

    Institute of Scientific and Technical Information of China (English)

    黄晓锋; 周宏; 何镇明

    2003-01-01

    The effect of cerium on ignition temperature of AZ91D magnesium alloy was studied. By the addition of cerium of 1%, the ignition temperature is raised by 180 ℃, so the magnesium alloy added with cerium can be melted in air. The burning temperature increases with the increasing of cerium. The structure and chemical compositions of the surface oxide film were investigated by XRD and Auger electron spectrometry(AES). The results of XRD indicate that the oxide film of the surface of ignition-inhibition magnesium alloy can change from loose structure of simple magnesia to compact composite structure consisting of magnesia, cerium oxide, Mg17 A112 and aluminum oxide, which has excellent ignition-inhibition effect. AES depth profile analysis shows that the oxide film can be divided into three layers. The outside layer is mainly made up of magnesia, the middle layer, which consists of cerium oxide, magnesia, and aluminum oxide, is compound and compact. Thermodynamic analysis indicates that the structure of the surface oxide film is accordant to the change of free energy and high vapor pressure of magnesium.

  4. Exposure of cerium oxide nanoparticles to kidney bean shows disturbance in the plant defense mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Majumdar, Sanghamitra [Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN) (United States); Peralta-Videa, Jose R. [Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); Environmental Science and Engineering PhD Program, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN) (United States); Bandyopadhyay, Susmita [Environmental Science and Engineering PhD Program, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN) (United States); Castillo-Michel, Hiram [European Synchrotron Radiation Facility, B.P. 220-38043 Grenoble, Cedex (France); Hernandez-Viezcas, Jose-Angel [Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN) (United States); Sahi, Shivendra [Department of Biology, Western Kentucky University, Bowling Green, KY 42101 (United States); Gardea-Torresdey, Jorge L., E-mail: jgardea@utep.edu [Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); Environmental Science and Engineering PhD Program, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN) (United States)

    2014-08-15

    Graphical abstract: - Highlights: • Kidney bean roots uptake nCeO{sub 2} primarily without biotransformation. • Cerium reached the root vascular tissues through gaps in the Casparian strip. • On longer exposure to high concentration, roots demonstrate stress response. • In leaves, guaiacol peroxidase plays a major role in ROS scavenging. - Abstract: Overwhelming use of engineered nanoparticles demands rapid assessment of their environmental impacts. The transport of cerium oxide nanoparticles (nCeO{sub 2}) in plants and their impact on cellular homeostasis as a function of exposure duration is not well understood. In this study, kidney bean plants were exposed to suspensions of ∼8 ± 1 nm nCeO{sub 2} (62.5 to 500 mg/L) for 15 days in hydroponic conditions. Plant parts were analyzed for cerium accumulation after one, seven, and 15 days of nCeO{sub 2} exposure. The primary indicators of stress like lipid peroxidation, antioxidant enzyme activities, total soluble protein and chlorophyll contents were studied. Cerium in tissues was localized using scanning electron microscopy and synchrotron μ-XRF mapping, and the chemical forms were identified using μ-XANES. In the root epidermis, cerium was primarily shown to exist as nCeO{sub 2}, although a small fraction (12%) was biotransformed to Ce(III) compound. Cerium was found to reach the root vascular tissues and translocate to aerial parts with time. Upon prolonged exposure to 500 mg nCeO{sub 2}/L, the root antioxidant enzyme activities were significantly reduced, simultaneously increasing the root soluble protein by 204%. In addition, leaf's guaiacol peroxidase activity was enhanced with nCeO{sub 2} exposure in order to maintain cellular homeostasis.

  5. Catalytic performance of cerium iron complex oxides for partial oxidation of methane to synthesis gas

    Institute of Scientific and Technical Information of China (English)

    LI Kongzhai; WANG Hua; WEI Yonggang; LIU Mingchun

    2008-01-01

    The cerium iron complex oxides oxygen carder was prepared by the co-precipitation method. The reactions between methane and lattice oxygen from the complex oxides were investigated in a fixed micro-reactor system. The reduced oxygen carrier could be re-oxidized by air and its initial state could be restored. The characterizations of the oxygen carriers were studied using XRD, O2-TPD, and H2-TPR. The results showed that the bulk lattice oxygen of CeO2-Fe2O3 was found to be suitable for the partial oxidation of methane to synthesis gas. There were two kinds of oxygen species on the oxygen carder: the stronger oxygen species that was responsible for the complete oxidation of methane, and the weaker oxygen species (bulk lattice oxygen) that was responsible for the selective oxidation of methane to CO and H2 at a higher temperature. Then, the lost bulk lattice oxygen could be selectively supplemented by air re-oxidation at an appropriate reaction con-dition. CeFeO3 appeared on the oxygen carrier after 10 successive redox cycles, however, it was not bad for the selectivity of CO and H2.

  6. Shifts in oxidation states of cerium oxide nanoparticles detected inside intact hydrated cells and organelles

    Energy Technology Data Exchange (ETDEWEB)

    Szymanski, Craig J.; Munusamy, Prabhakaran; Mihai, Cosmin; Xie, Yumei; Hu, Dehong; Gilles, Marry K.; Tyliszczak, T.; Thevuthasan, Suntharampillai; Baer, Donald R.; Orr, Galya

    2015-09-01

    Cerium oxide nanoparticles (CNPs) have been shown to induce diverse biological effects, ranging from toxic to beneficial. The beneficial effects have been attributed to the potential antioxidant activity of CNPs via certain redox reactions, depending on their oxidation state or Ce3+/Ce4+ ratio. However, this ratio is strongly dependent on the environment and age of the nanoparticles and it is unclear whether and how the complex intracellular environment impacts this ratio and the possible redox reactions of CNPs. To identify any changes in the oxidation state of CNPs in the intracellular environment and better understand their intracellular reactions, we directly quantified the oxidation states of CNPs outside and inside intact hydrated cells and organelles using correlated scanning transmission x-ray and super resolution fluorescence microscopies. By analyzing hundreds of small CNP aggregates, we detected a shift to a higher Ce3+/Ce4+ ratio in CNPs inside versus outside the cells, indicating a net reduction of CNPs in the intracellular environment. We further found a similar ratio in the cytoplasm and in the lysosomes, indicating that the net reduction occurs earlier in the internalization pathway. Together with oxidative stress and toxicity measurements, our observations identify a net reduction of CNPs in the intracellular environment, which is consistent with their involvement in potentially beneficial oxidation reactions, but also point to interactions that can negatively impact the health of cells.

  7. Stability and morphology of cerium oxide surfaces in an oxidizing environment: A first-principles investigation

    Science.gov (United States)

    Fronzi, Marco; Soon, Aloysius; Delley, Bernard; Traversa, Enrico; Stampfl, Catherine

    2009-09-01

    We present density functional theory investigations of the bulk properties of cerium oxides (CeO2 and Ce2O3) and the three low index surfaces of CeO2, namely, (100), (110), and (111). For the surfaces, we consider various terminations including surface defects. Using the approach of "ab initio atomistic thermodynamics," we find that the most stable surface structure considered is the stoichiometric (111) surface under "oxygen-rich" conditions, while for a more reducing environment, the same (111) surface, but with subsurface oxygen vacancies, is found to be the most stable one, and for a highly reducing environment, the (111) Ce-terminated surface becomes energetically favored. Interestingly, this latter surface exhibits a significant reconstruction in that it becomes oxygen terminated and the upper layers resemble the Ce2O3(0001) surface. This structure could represent a precursor to the phase transition of CeO2 to Ce2O3.

  8. Effects of cerium oxide supplementation to laying hen diets on performance, egg quality, some antioxidant enzymes in serum and lipid oxidation in egg yolk.

    Science.gov (United States)

    Bölükbaşı, S C; Al-Sagan, A A; Ürüşan, H; Erhan, M K; Durmuş, O; Kurt, N

    2016-08-01

    This study was conducted to determine the effects of dietary cerium oxide levels (0, 100, 200, 300 or 400 mg/kg) on the laying performance, egg quality, some blood serum parameters and egg lipid peroxidation of laying hen. In total, one hundred and twenty 22-week-old brown Lohman LSL laying hens were randomly assigned to five groups equally (n = 24). Each treatment was replicated six times. Dietary supplementation of cerium oxide had no significant effect on feed intake and egg weight. The addition of cerium oxide to the laying hens' feed improved feed conversion ratio and increased (p laying hens feed led to a significant (p laying hen diets. It was also observed that serum superoxide dismutase (SOD) activity and malondialdehyde (MDA) concentration decreased significantly with supplementation of cerium oxide in diets. Inclusion of cerium oxide resulted in a significant reduction in thiobarbituric acid reactive substance (TBARS) values in egg yolk in this study. It can be concluded that the addition of cerium oxide had positive effects on egg production, feed conversion ratio and egg shelf life. Based on the results of this study, it could be advised to supplement laying hens feed with cerium oxide as feed additives.

  9. Synthesis of mesoporous cerium-zirconium mixed oxides by hydrothermal templating method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Mesoporous cerium-zirconium mixed oxides were prepared by hydrothermal method using cetyl trimethyl ammonium bromide (CTAB) as template.The effects of amount of template,pH value of solution and hydrothermal temperature on mesostructure of samples were systematically investigated.The final products were characterized by XRD,TEM,FT-IR,and BET.The results indicate that all the cerium-zirconium mixed oxides present a meso-structure.At molar ratio of n(CTAB)/n((Ce)+(Zr))=0.15,pH value of 9,and hydrothermal temperature of 120 ℃,the samples obtained possess a specific surface area of 207.9 m2/g with pore diameter of 3.70 nm and pore volume of 0.19 cm3/g.

  10. Monte Carlo radiative transfer simulation of a cavity solar reactor for the reduction of cerium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Villafan-Vidales, H.I.; Arancibia-Bulnes, C.A.; Dehesa-Carrasco, U. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Privada Xochicalco s/n, Col. Centro, A.P. 34, Temixco, Morelos 62580 (Mexico); Romero-Paredes, H. [Departamento de Ingenieria de Procesos e Hidraulica, Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco No.186, Col. Vicentina, A.P. 55-534, Mexico D.F 09340 (Mexico)

    2009-01-15

    Radiative heat transfer in a solar thermochemical reactor for the thermal reduction of cerium oxide is simulated with the Monte Carlo method. The directional characteristics and the power distribution of the concentrated solar radiation that enters the cavity is obtained by carrying out a Monte Carlo ray tracing of a paraboloidal concentrator. It is considered that the reactor contains a gas/particle suspension directly exposed to concentrated solar radiation. The suspension is treated as a non-isothermal, non-gray, absorbing, emitting, and anisotropically scattering medium. The transport coefficients of the particles are obtained from Mie-scattering theory by using the optical properties of cerium oxide. From the simulations, the aperture radius and the particle concentration were optimized to match the characteristics of the considered concentrator. (author)

  11. Diesel Engine Emission Reduction Using Catalytic Nanoparticles: An Experimental Investigation

    Directory of Open Access Journals (Sweden)

    Ajin C. Sajeevan

    2013-01-01

    Full Text Available Cerium oxide being a rare earth metal with dual valance state existence has exceptional catalytic activity due to its oxygen buffering capability, especially in the nanosized form. Hence when used as an additive in the diesel fuel it leads to simultaneous reduction and oxidation of nitrogen dioxide and hydrocarbon emissions, respectively, from diesel engine. The present work investigates the effect of cerium oxide nanoparticles on performance and emissions of diesel engine. Cerium oxide nanoparticles were synthesized by chemical method and techniques such as TEM, EDS, and XRD have been used for the characterization. Cerium oxide was mixed in diesel by means of standard ultrasonic shaker to obtain stable suspension, in a two-step process. The influence of nanoparticles on various physicochemical properties of diesel fuel has also been investigated through extensive experimentation by means of ASTM standard testing methods. Load test was done in the diesel engine to investigate the effect of nanoparticles on the efficiency and the emissions from the engine. Comparisons of fuel properties with and without additives are also presented.

  12. DEVELOPMENT OF A COMPOSITE OF POLY-Ɛ-CAPROLACTONE-CERIUM OXIDE

    OpenAIRE

    Alejandra Melissa Martínez-Hernández; Simón Yobanny Reyes-López

    2017-01-01

    Nanotechnology is used in a variety of sectors for the manufacture of materials. However, there is a risk from exposure to nanomaterials due to their chemical composition and processing form, giving rise to health risks. CeO2 particles present antioxidant properties that accelerate the wound poly-Ɛ-caprolactone (PCL) provides the property of biocompatibility and biodegradability of the material. For the regulation of the transport and release of cerium oxide particles was incorporated into a ...

  13. CO Responses of Sensors Based on Cerium Oxide Thick Films Prepared from Clustered Spherical Nanoparticles

    OpenAIRE

    Woosuck Shin; Takafumi Akamatsu; Toshio Itoh; Ichiro Matsubara; Noriya Izu

    2013-01-01

    Various types of CO sensors based on cerium oxide (ceria) have been reported recently. It has also been reported that the response speed of CO sensors fabricated from porous ceria thick films comprising nanoparticles is extremely high. However, the response value of such sensors is not suitably high. In this study, we investigated methods of improving the response values of CO sensors based on ceria and prepared gas sensors from core-shell ceria polymer hybrid nanoparticles. These hybrid nano...

  14. Nanoceria and bulk cerium oxide effects on the germination of asplenium adiantum-nigrum spores

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Garay, A.; Pintos, B.; Manzanera, J.A.; Prada, C.; Martin, L.; Gabriel y Galan, J.M.

    2016-07-01

    Aim of the study: The effect of cerium oxide engineered nanoparticles on the spore germination of the fern. Asplenium adiantum-nigrum. Area of study: France, Britanny Region, Finistére Department, Plougonvelin, in rocks near the sea. Material and methods: Asplenium spores were cultured in vitro on agar medium with Nano-CeO2 (less than 25 nm particle size) and bulk-CeO2. The addition of each nano- and bulk particles ranged from 0 to 3000 mg L-1. Observations on rhizoidal and prothallial cells during first stages of gametophyte development were made. The No-Observed-Adverse-Effect concentration (NOAEC) and Lowest-Observed-Adverse-Effect-Concentration (LOEC) values for spore germination rate data were analyzed. Main results: Germination was speeded up by 100 to 2000 mg L-1 nanoceria, while bulk cerium oxide had the same effect for 500 to 200 mg L-1 concentrations. Present results showed cellular damage in the protonema while rhizoid cells seemed not to be affected, as growth and membrane integrity remained. Research highlights: Both nanosized and bulk cerium oxide are toxic for the fern Asplenium adiantum-nigrum, although diverse toxicity patterns were shown for both materials. Diverse toxic effects have been observed: chloroplast membrane damage and lysis, cell wall and membrane disruption which leads to cell lysis; and alterations in morphology and development. (Author)

  15. Nanoceria and bulk cerium oxide effects on the germination of asplenium adiantum-nigrum spores

    Directory of Open Access Journals (Sweden)

    Aranzazu Gomez-Garay

    2016-12-01

    Full Text Available Aim of study: The effect of cerium oxide engineered nanoparticles on the spore germination of the fern. Asplenium adiantum-nigrum. Area of study: France, Britanny Region, Finistére Department, Plougonvelin, in rocks near the sea. Material and methods: Asplenium spores were cultured in vitro on agar medium with Nano-CeO2 (less than 25 nm particle size and bulk-CeO2. The addition of each nano- and bulk particles ranged from 0 to 3000 mg L-1. Observations on rhizoidal and prothallial cells during first stages of gametophyte development were made. The No-Observed-Adverse-Effect concentration (NOAEC and Lowest-Observed-Adverse-Effect-Concentration (LOEC values for spore germination rate data were analyzed.  Main results: Germination was speeded up by 100 to 2000 mg L-1 nanoceria, while bulk cerium oxide had the same effect for 500 to 200 mg L-1 concentrations. Present results showed cellular damage in the protonema while rhizoid cells seemed not to be affected, as growth and membrane integrity remained. Research highlights: Both nanosized and bulk cerium oxide are toxic for the fern Asplenium adiantum-nigrum, although diverse toxicity patterns were shown for both materials. Diverse toxic effects have been observed: chloroplast membrane damage and lysis, cell wall and membrane disruption which leads to cell lysis; and alterations in morphology and development. Keywords: Nanoparticles; rhizoid; prothallus; chloroplast; fern.

  16. Effect of cerium oxide addition on electrical properties of ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, D.M. [National Research Center, Dokki, Giza (Egypt). Dept. of Ceramics; Mounir, M. [Dept. of Physics, Cairo Univ., Giza (Egypt); Mahgoub, A.S. [Cairo Univ., Giza (Egypt). Dept. of Chemistry; Turky, G. [Dept. of Physics, National Research Center, Dokki, Giza (Egypt); El-Desouky, O.A. [Cer. Cleopatra Co., Ramadan City (Egypt)

    2002-07-01

    Mixtures of ZnO and Ce{sub 6} O{sub 11} as additive were prepared by solid state reaction from the calcined oxides with the following proportions: 0.03, 0.08, 0.1, 0.2 and 0.4 mole. Disc specimens 1.2 cm 5 cm in diameter and 0.3 cm thickness were processed under a force of 70 kN and fired at 1150 C/ 30 minutes. XRD revealed the presence of limited solid solution of cerium in ZnO, as evident from the shift in the peaks [0.03-0.04 A ] up to 0.1 mole addition and remains constant. SEM revealed the presence of inter-granular phase. EDAX showed it to be a mixture of ZnO and Ce{sub 6}O{sub 11}. Also cerium was detected in the ZnO grains confirming the XRD results. RCL circuit was used to measure the capacitance and resistance at different frequencies at room temperature. The dielectric constant and conductivity were calculated. The change in resistivity with temperature was followed up to 523 K. The change in dielectric strength with temperature at spot frequency of 10 kHz is demonstrated. The electrical conductivity was found to increase with the proportion of cerium oxide up to 0.2 mole then decreased. (orig.)

  17. Highly stable, mesoporous mixed lanthanum-cerium oxides with tailored structure and reducibility

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Shuang; Broitman, Esteban; Wang, Yanan; Cao, Anmin; Veser, Goetz

    2011-05-01

    Pure and mixed lanthanum and cerium oxides were synthesized via a reverse microemulsion-templated route. This approach yields highly homogeneous and phase-stable mixed oxides with high surface areas across the entire range of La:Ce ratios from pure lanthana to pure ceria. Surprisingly, all mixed oxides show the fluorite crystal structure of ceria, even for lanthanum contents as high as 90%. Varying the La:Ce ratio not only allows tailoring of the oxide morphology (lattice parameter, pore structure, particle size, and surface area), but also results in a fine-tuning of the reducibility of the oxide which can be explained by the creation of oxygen vacancies in the ceria lattice upon La addition. Such finely controlled syntheses, which enable the formation of stable, homogeneous mixed oxides across the entire composition range, open the path towards functional tailoring of oxide materials, such as rational catalyst design via fine-tuning of redox activity.

  18. Near-Road Modeling and Measurement of Particles Generated by Nanoparticle Diesel Fuel Additive Use

    Science.gov (United States)

    Cerium oxide (ceria) nanoparticles (n-Ce) are used as a fuel-borne catalyst in diesel engines to reduce particulate emissions, yet the environmental and human health impacts of the ceria-doped diesel exhaust aerosols are not well understood. To bridge the gap between emission mea...

  19. UV-Shielding and Catalytic Characteristics of Nanoscale Zinc-Cerium Oxides

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Fine particles of zinc-cerium oxides (ZCO) used as an ultraviolet filter were prepared via combustion synthesis route. The catalytic activity, UV-shielding performance, surface modification and application of ZCO in polyester varnish were discussed in detail. The experimental results indicate that the photo-catalytic activity of ZCO is much smaller than these of ZnO and TiO2; the oxidation catalytic activity of ZCO is far lower than that of CeO2; the ZCO has shown excellent ultraviolet absorption in the range of UV;addition modified ZCO (MZCO) into polyester will enhance the UV-shielding capability of polyester.

  20. Copper-cerium oxides supported on carbon nanomaterial for preferential oxidation of carbon monoxide

    Institute of Scientific and Technical Information of China (English)

    高美怡; 江楠; 赵宇宏; 徐长进; 苏海全; 曾尚红

    2016-01-01

    The CuxO-CeO2/Fe@CNSs, CuxO-CeO2/MWCNTs-Co and CuxO-CeO2/MWCNTs-Ni catalysts were prepared by the im-pregnation method and characterized by transmission electron microscopy, scanning electron microscopy, X-ray powder diffrac-tion, H2-temperature programmed reduction and N2 adsorption-desorption techniques. It was found that the Fe nanoparticles were encapsulated into the multi-layered carbon nanospheres (CNSs). However, the multi-wall carbon nanotubes (MWCNTS) were generated on the Co/Al2O3 and Ni/Al2O3 precursor. The addition of carbon nanomaterial as supports could improve structural properties and low-temperature activity of the CuO-CeO2 catalyst, and save the used amount of metal catalysts in the temperature range with high selectivity for CO oxidation. The copper-cerium oxides supported on carbon nanomaterial had good resistence to H2O and CO2.

  1. Chromium VI adsorption on cerium oxide nanoparticles and morphology changes during the process

    Energy Technology Data Exchange (ETDEWEB)

    Recillas, Sonia; Colon, Joan [Department of Chemical Engineering, Engineering School, Autonomous University of Barcelona, 08193 Bellaterra (Spain); Casals, Eudald; Gonzalez, Edgar [Catalan Institute of Nanotechnology, Autonomous University of Barcelona Campus, 08193 Bellaterra (Spain); Puntes, Victor [Catalan Institute of Nanotechnology, Autonomous University of Barcelona Campus, 08193 Bellaterra (Spain); Catalan Institute of Research and Advanced Studies, Passeig Lluis Companys, 23, 08010 Barcelona (Spain); Sanchez, Antoni, E-mail: antoni.sanchez@uab.cat [Department of Chemical Engineering, Engineering School, Autonomous University of Barcelona, 08193 Bellaterra (Spain); Font, Xavier [Department of Chemical Engineering, Engineering School, Autonomous University of Barcelona, 08193 Bellaterra (Spain)

    2010-12-15

    In this study, suspended cerium oxide nanoparticles stabilized with hexamethylenetetramine were used for the removal of dissolved chromium VI in pure water. Several concentrations of adsorbent and adsorbate were tested, trying to cover a large range of possible real conditions. Results showed that the Freundlich isotherm represented well the adsorption equilibrium reached between nanoparticles and chromium, whereas adsorption kinetics could be modeled by a pseudo-second-order expression. The separation of chromium-cerium nanoparticles from the medium and the desorption of chromium using sodium hydroxide without cerium losses was obtained. Nanoparticles agglomeration and morphological changes during the adsorption-desorption process were observed by TEM. Another remarkable result obtained in this study is the low toxicity in the water treated by nanoparticles measured by the Microtox commercial method. These results can be used to propose this treatment sequence for a clean and simple removal of drinking water or wastewater re-use when a high toxicity heavy metal such as chromium VI is the responsible for water pollution.

  2. Isothermal Kinetics of Catalyzed Air Oxidation of Diesel Soot

    Directory of Open Access Journals (Sweden)

    R. Prasad

    2011-01-01

    Full Text Available To comply with the stringent emission regulations on soot, diesel vehicles manufacturers more and more commonly use diesel particulate filters (DPF. These systems need to be regenerated periodically by burning soot that has been accumulated during the loading of the DPF. Design of the DPF requires rate of soot oxidation. This paper describes the kinetics of catalytic oxidation of diesel soot with air under isothermal conditions. Kinetics data were collected in a specially designed mini-semi-batch reactor. Under the high air flow rate assuming pseudo first order reaction the activation energy of soot oxidation was found to be, Ea = 160 kJ/ mol. ©2010 BCREC UNDIP. All rights reserved(Received: 14th June 2010, Revised: 18th July 2010, Accepted: 9th August 2010[How to Cite: R. Prasad, V.R. Bella. (2010. Isothermal Kinetics of Catalyzed Air Oxidation of Diesel Soot. Bulletin of Chemical Reaction Engineering and Catalysis, 5(2: 95-101. doi:10.9767/bcrec.5.2.796.95-101][DOI:http://dx.doi.org/10.9767/bcrec.5.2.796.95-101 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/796]Cited by in: ACS 1 |

  3. The protective effects of cerium oxide nanoparticles against hepatic oxidative damage induced by monocrotaline

    Directory of Open Access Journals (Sweden)

    Kamal A Amin

    2011-01-01

    Full Text Available Kamal A Amin1, Mohamed S Hassan2, El-Said T Awad3, Khalid S Hashem11Department of Biochemistry, 2Department of Internal Medicine, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt; 3Department of Biochemistry, Faculty of Veterinary Medicine, Cairo University, Cairo, EgyptObjective: The objective of the present study was to determine the ability of cerium oxide (CeO2 nanoparticles to protect against monocrotaline (MCT-induced hepatotoxicity in a rat model.Method: Twenty male Sprague Dawley rats were arbitrarily assigned to four groups: control (received saline, CeO2 (given 0.0001 nmol/kg intraperitoneally [IP], MCT (given 10 mg/kg body weight IP as a single dose, and MCT + CeO2 (received CeO2 both before and after MCT. Electron microscopic imaging of the rat livers was carried out, and hepatic total glutathione (GSH, glutathione reductase (GR, glutathione peroxidase (GPX, glutathione S-transferase (GST, superoxide dismutase (SOD, and catalase (CAT enzymatic activities were quantified.Results: Results showed a significant MCT-induced decrease in total hepatic GSH, GPX, GR, and GST normalized to control values with concurrent CeO2 administration. In addition, MCT produced significant increases in hepatic CAT and SOD activities, which also ameliorated with CeO2.Conclusions: These results indicate that CeO2 acts as a putative novel and effective hepatoprotective agent against MCT-induced hepatotoxicity.Keywords: monocrotaline, ceruim oxide nanoparticle, hepatotoxicity, oxidative stress

  4. Custom cerium oxide nanoparticles protect against a free radical mediated autoimmune degenerative disease in the brain.

    Science.gov (United States)

    Heckman, Karin L; DeCoteau, William; Estevez, Ana; Reed, Kenneth J; Costanzo, Wendi; Sanford, David; Leiter, James C; Clauss, Jennifer; Knapp, Kylie; Gomez, Carlos; Mullen, Patrick; Rathbun, Elle; Prime, Kelly; Marini, Jessica; Patchefsky, Jamie; Patchefsky, Arthur S; Hailstone, Richard K; Erlichman, Joseph S

    2013-12-23

    Cerium oxide nanoparticles are potent antioxidants, based on their ability to either donate or receive electrons as they alternate between the +3 and +4 valence states. The dual oxidation state of ceria has made it an ideal catalyst in industrial applications, and more recently, nanoceria's efficacy in neutralizing biologically generated free radicals has been explored in biological applications. Here, we report the in vivo characteristics of custom-synthesized cerium oxide nanoparticles (CeNPs) in an animal model of immunological and free-radical mediated oxidative injury leading to neurodegenerative disease. The CeNPs are 2.9 nm in diameter, monodispersed and have a -23.5 mV zeta potential when stabilized with citrate/EDTA. This stabilizer coating resists being 'washed' off in physiological salt solutions, and the CeNPs remain monodispersed for long durations in high ionic strength saline. The plasma half-life of the CeNPs is ∼4.0 h, far longer than previously described, stabilized ceria nanoparticles. When administered intravenously to mice, the CeNPs were well tolerated and taken up by the liver and spleen much less than previous nanoceria formulations. The CeNPs were also able to penetrate the brain, reduce reactive oxygen species levels, and alleviate clinical symptoms and motor deficits in mice with a murine model of multiple sclerosis. Thus, CeNPs may be useful in mitigating tissue damage arising from free radical accumulation in biological systems.

  5. Selective catalytic oxidation of ammonia over copper-cerium composite catalyst.

    Science.gov (United States)

    Lou, Jie-Chung; Hung, Chang-Mao; Yang, Sheng-Fu

    2004-01-01

    This work considers the oxidation of ammonia (NH3) by selective catalytic oxidation (SCO) over a copper (Cu)-cerium (Ce) composite catalyst at temperatures between 150 and 400 degrees C. A Cu-Ce composite catalyst was prepared by coprecipitation of copper nitrate and cerium nitrate at various molar concentrations. This study also considers how the concentration of influent NH3 (500-1000 ppm), the space velocity (72,000-110,000 hr(-1)), the relative humidity (12-18%) and the concentration of oxygen (4-20%) affect the operational stability and the capacity for removing NH3. The effects of the O2 and NH3 content of the carrier gas on the catalyst's reaction rate also are considered. The experimental results show that the extent of conversion of NH3 by SCO in the presence of the Cu-Ce composite catalyst was a function of the molar ratio. The NH3 was removed by oxidation in the absence of Cu-Ce composite catalyst, and approximately 99.2% NH3 reduction was achieved during catalytic oxidation over the Cu-Ce (6:4, molar/molar) catalyst at 400 degrees C with an O2 content of 4%. Moreover, the effect of the initial concentration and reaction temperature on the removal of NH3 in the gaseous phase was also monitored at a gas hourly space velocity of less than 92,000 hr(-1).

  6. Oxidative desulfurization of synthetic diesel using supported catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Caero, Luis Cedeno; Hernandez, Emiliano [UNICAT, Departamento de Ingenieria Quimica, Facultad de Quimica, UNAM. Cd. Universitaria, 04510 Mexico D.F. (Mexico); Pedraza, Francisco; Murrieta, Florentino [Programa de Tratamiento en Crudo Maya, Instituto Mexicano del Petroleo, Eje Central 152, 07730 Mexico D.F. (Mexico)

    2005-10-30

    In this work, an experimental study was carried out to obtain the reactivity of different organic sulfur compounds and to examine the effect of various parameters, such as temperature, solvent and the amount of oxidant reagent in oxidative desulfurization (ODS) reaction. The oxidation was performed through a vanadium based catalyst in the presence of hydrogen peroxide under mild reaction conditions, atmospheric pressure and temperature range of 303-343K. The sulfur compounds studied were: 2-methylthiophene (2-MT), 2,5-dimethylthiophene (2,5-DMT), benzothiophene (BT), dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MDBT) and 4,6-dimethyl dibenzothiophene (4,6-DMDBT). All of them are typical thiophenic sulfur compounds present in diesel fuels. A synthetic diesel was prepared with these compounds in hexadecane. The experimental results showed that oxidation reactivities decreased according to the following order: DBT>BT>4-MDBT>2-MT>2,5-DMT>4,6-DMDBT. A fraction of the S compounds removed from the diesel phase, was not transformed to its corresponding sulfone, under these experimental conditions. It is only removed as sulfur compound by extraction, without ODS reaction. The surplus amount of oxidant promoted the equilibrium reaction, but the thermal decomposition of oxidant and oxidation reactions produces water, which inhibits the ODS reactions. Therefore, the controlled addition of H{sub 2}O{sub 2} improves ODS reactivity of sulfur compounds.

  7. Relationship between surface area and crystal size of pure and doped cerium oxides

    Institute of Scientific and Technical Information of China (English)

    C.; Bueno-Ferrer; S.; Parres-Esclapez; D.; Lozano-Castelló; A.; Bueno-López

    2010-01-01

    Pure and Zr, La or Pr-doped cerium oxides were characterised by transmission electron microscopy (TEM), N2 adsorption-desorption at -196 oC and X-ray diffraction (XRD). For crystal sizes calculation, the Scherrer and Williamson-Hall equations were compared, and the relationship between surface area and crystal size was critically discussed. It was demonstrated that the Williamson-Hall equation must be used instead of the Scherrer equation to calculate crystal sizes, since the latter equation underestimated ...

  8. Surface structures of cerium oxide nanocrystalline particles from the size dependence of the lattice parameters

    Science.gov (United States)

    Tsunekawa, S.; Ito, S.; Kawazoe, Y.

    2004-10-01

    Cerium oxide nanocrystalline particles are synthesized and monodispersed in the size range from 2 to 8nm in diameter. The dependence of the lattice parameters on particle size is obtained by x-ray and electron diffraction analyses. The size dependence well coincides with the estimation based on the assumption that the surface is composed of one layer of Ce2O3 and the inside consists of CeO2. The effect of particle size on lattice parameters is discussed from the differences in the fabrication method and the surface structure.

  9. Improvement of corrosion resistance of AZ31 Mg alloy by anodizing with co-precipitation of cerium oxide

    Institute of Scientific and Technical Information of China (English)

    Salah Abdelghany SALMAN; Ryoichi ICHINO; Masazumi OKIDO

    2009-01-01

    Anodizing of AZ31 Mg alloy in NaOH solution by co-precipitation of cerium oxide was investigated. The chemical composition and phase structure of the coating film were determined via optical microscopy, SEM and XRD. The corrosion properties of the anodic film were characterized by using potentiodynamic polarization curves in 17 mmol/L NaCl and 0.1 mol/L Na2SO4 solution at 298 K. The corrosion resistance of AZ31 magnesium alloy is significantly improved by adding cerium oxide to alkaline solution. In addition, the surface properties are enhanced and the film contains no crack.

  10. Destructive adsorption of carbon tetrachloride on lanthanum and cerium oxides

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Rosynek, M.P.; Lunsford, J.H.

    1999-01-01

    The destructive adsorption of CCl4 on La2O3 and CeO2 in the absence of any oxidant, such as oxygen, has been studied by X-ray photoelectron spectroscopy and insitu Raman spectroscopy as a function of the reaction temperature and the amount of CCl4 injected. La2O3 was much more reactive than CeO2, an

  11. Determination of Ideal Broth Formulations Needed to Prepare Hydrous Cerium Oxide Microspheres via the Internal Gelation Process

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Jack Lee [ORNL; Chi, Anthony [ORNL

    2009-02-01

    A simple test tube methodology was used to determine optimum process parameters for preparing hydrous cerium oxide microspheres via the internal gelation process.1 Broth formulations of cerium ammonium nitrate [(NH4)2Ce(NO3)6], hexamethylenetetramine, and urea were found that can be used to prepare hydrous cerium oxide gel spheres in the temperature range of 60 to 90 C. A few gel-forming runs were made in which microspheres were prepared with some of these formulations to be able to equate the test-tube gelation times to actual gelation times. These preparations confirmed that the test-tube methodology is reliable for determining the ideal broth formulations.

  12. Cerium oxide-chitosan based nanobiocomposite for food borne mycotoxin detection

    Science.gov (United States)

    Kaushik, Ajeet; Solanki, Pratima R.; Pandey, M. K.; Ahmad, Sharif; Malhotra, Bansi D.

    2009-10-01

    Cerium oxide nanoparticles (NanoCeO2) and chitosan (CH) based nanobiocomposite film deposited onto indium-tin-oxide coated glass substrate has been used to coimmobilize rabbit immunoglobin (r-IgGs) and bovine serum albumin (BSA) for food borne mycotoxin [ochratoxin-A (OTA)] detection. Electrochemical studies reveal that presence of NanoCeO2 increases effective electro-active surface area of CH-NanoCeO2/indium tin oxide (ITO) nanobiocomposite resulting in high loading of r-IgGs. BSA/r-IgGs/CH-NanoCeO2/ITO immunoelectrode exhibits improved linearity (0.25-6.0 ng/dl), detection limit (0.25 ng/dl), response time (25 s), sensitivity (18 μA/ng dl-1 cm-2), and regression coefficient (r2˜0.997).

  13. Porous microspheres of manganese-cerium mixed oxides by a polyvinylpyrrolidone assisted solvothermal method

    Science.gov (United States)

    Schmit, F.; Bois, L.; Chiriac, R.; Toche, F.; Chassagneux, F.; Descorme, C.; Besson, M.; Khrouz, L.

    2017-04-01

    Mixed cerium manganese oxides were synthesized using a polyvinylpyrrolidone (PVP) assisted solvothermal method. Materials obtained after calcination at 400 °C were characterized by X-ray diffraction, scanning and transmission electron microscopies, electron paramagnetic resonance (EPR), Raman spectroscopy, thermal analysis and nitrogen adsorption/desorption isotherms. The influence of the synthesis parameters on the oxide structure, such as the Mn:Ce ratio or the amount of PVP, was discussed. Micrometric spheres of mixed Mn-Ce oxides, resulting from the aggregation of 100 nm porous snowflakes, were successfully synthesized. These snowflakes were formed from the aggregation of smaller oriented crystallites (size 4 nm). The hydrothermal stability of these materials was also investigated.

  14. Cyanex 923 as the extractant in a rare earth element impurity analysis of high-purity cerium oxide.

    Science.gov (United States)

    Duan, Taicheng; Li, Hongfei; Kang, JianZhen; Chen, Hangting

    2004-06-01

    In this work, the feasibility of employing Cyanex 923 as an extractant into the non-cerium REE (rare earth elements) impurity analysis of high-purity cerium oxide was investigated. Through investigations on the choice of the extraction medium, the optimium extraction acidity, matrix Ce4+ effect on the non-cerium REE ion extraction, the optimium extractant concentration and suitable extracting time, and oscillation strengh, it was found that when the phase ratio was at 1:1 and the acicidity was about 2% H2SO4, by gently shaking by hand for about 2 min, 10 mL of 30% Cyanex 923 could not extract even for a 20 ng amount of non-cerium REE3+ ions. However, the extraction efficiency for Ce4+ of 100 mg total amount under the same conditions was about 96%, indicating that a 25-fold preconcentration factor could be achieved. Thus, it was concluded that Cyanex 923 could be used in a REE impurity analysis of 99.9999% or so pure cerium oxide for primary sepapation to elimilate matrix-induced interferences encountered in an ICP-MS (inductively coupled plasma mass spectroscopy) determination.

  15. Honeycomb nano cerium oxide fabricated by vacuum drying process with sodium alginate

    Science.gov (United States)

    Zhao, Guozheng; Li, Changbo; Zhang, Honglin

    2017-06-01

    Nano cerium oxide (CeO2) with honeycomb structure were synthesized simply and rapidly by vacuum drying method with sodium alginate as the biological template agent, Ce(NO3)3·6H2O as cerium source. The composition, aperture size, specific surface area and morphology of the prepared samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), N2 adsorption-desorption and scanning electron microscopy (SEM). Simultaneously, the effects on the morphology of the samples, which were caused by the drying method and the concentration of sodium alginate, were investigated. The results indicate that the prepared samples were nano CeO2 with high crystallinity and uniform dispersion, most of which had mesoporous, macroporous and honeycomb structure. The specific surface area of CeO2 is 210.0 m2/g, and the average aperture is 12.77 nm. The prepared samples can act as catalyst in the catalytic wet oxidation process for the treatment of high concentration organic wastewater, and the COD removal rate could exceed 90%.

  16. Cerium oxide for the destruction of chemical warfare agents: A comparison of synthetic routes

    Energy Technology Data Exchange (ETDEWEB)

    Janoš, Pavel, E-mail: pavel.janos@ujep.cz [Faculty of the Environment, University of Jan Evangelista Purkyně, Králova Výšina 7, 400 96 Ústí nad Labem (Czech Republic); Henych, Jiří [Faculty of the Environment, University of Jan Evangelista Purkyně, Králova Výšina 7, 400 96 Ústí nad Labem (Czech Republic); Institute of Inorganic Chemistry AS CR v.v.i., 25068 Řež (Czech Republic); Pelant, Ondřej; Pilařová, Věra; Vrtoch, Luboš [Faculty of the Environment, University of Jan Evangelista Purkyně, Králova Výšina 7, 400 96 Ústí nad Labem (Czech Republic); Kormunda, Martin [Faculty of Sciences, University of Jan Evangelista Purkyně, České Mládeže 8, 400 96 Ústí nad Labem (Czech Republic); Mazanec, Karel [Military Research Institute, Veslařská 230, 637 00 Brno (Czech Republic); and others

    2016-03-05

    Highlights: • Four synthetic routes were compared to prepare the nanoceria-based reactive sorbents. • The sorbents prepared by homogeneous hydrolysis destroy efficiently the soman and VX nerve agents. • Toxic organophosphates are converted to less-dangerous products completely within a few minutes. • Surface non-stoichiometry and −OH groups promote the destruction by the S{sub N}2 mechanism. - Abstract: Four different synthetic routes were used to prepare active forms of cerium oxide that are capable of destroying toxic organophosphates: a sol–gel process (via a citrate precursor), homogeneous hydrolysis and a precipitation/calcination procedure (via carbonate and oxalate precursors). The samples prepared via homogeneous hydrolysis with urea and the samples prepared via precipitation with ammonium bicarbonate (with subsequent calcination at 500 °C in both cases) exhibited the highest degradation efficiencies towards the extremely dangerous nerve agents soman (O-pinacolyl methylphosphonofluoridate) and VX (O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate) and the organophosphate pesticide parathion methyl. These samples were able to destroy more than 90% of the toxic compounds in less than 10 min. The high degradation efficiency of cerium oxide is related to its complex surface chemistry (presence of surface −OH groups and surface non-stoichiometry) and to its nanocrystalline nature, which promotes the formation of crystal defects on which the decomposition of organophosphates proceeds through a nucleophilic substitution mechanism that is not dissimilar to the mechanism of enzymatic hydrolysis of organic phosphates by phosphotriesterase.

  17. FT-IR Studies of Cerium Oxide Nanoparticles and Natural Zeolite Materials

    Directory of Open Access Journals (Sweden)

    Oana Lelia Pop

    2015-05-01

    Full Text Available An emerging topic of our days is nanoscience and nanotechnology successfully applied in the food industry. Characteristics such as size, surface area and morphology can modify the basic properties and the chemical reactivity of the nanomaterials. The breakthrough of innovative materials, processes, and phenomena at the nanoscale, as well as the progress of new experimental and theoretical techniques for research, supply novel opportunities for the expansion of original nanosystems and nanostructured materials. These study examine two types of nanoparticles, namely cerium oxide nanoparticles (CeO2 NP and natural zeolites. In view of the importance of CeO2 NP in various biological applications, the primary objective of this study is to characterise four samples of CeO2 NP in order to understand the role of the synthesis process in the final product. Nanocrystalline natural zeolites are materials with interesting properties which allows them to be used as adjuvant in many therapies. The characterisation of CeO2 NP and two types of natural zeolites using Fourier Transform Infrared (FT-IR spectroscopy is described. Therefore, this study examined two types of nanomaterials, namely cerium oxide nanoparticles and zeolites, for further applications on microorganisms and living cells.

  18. Effect of cerium ion implantation on the oxidation behavior of zircaloy-4 at 500 degree sign C

    CERN Document Server

    Chen, X W; Yu, H R; Zhou, Q G; Chen, B S

    2002-01-01

    In order to investigate the oxidation behavior changes of zircaloy-4 induced by cerium ion implantation using a MEVVA source at an energy of 40 keV with a dose range from 1x10 sup 1 sup 6 to 1x10 sup 1 sup 7 ions/cm sup 2 at the maximum temperature of 130 degree sign C, weight gain curves of the different specimens including as-received zircaloy-4 and cerium-implanted zircaloy-4 were measured after oxidation in air at 500 degree sign C for 100 min. It was obviously found that a significant improvement was achieved in the oxidation behavior of cerium ion implanted zircaloy-4 compared with that of the as-received zircaloy-4. The depth profile of the element composition in the surface region of the samples was obtained by Auger electron spectroscopy, and the valence of the oxides in the scale was analyzed by X-ray photoemission spectroscopy. Glancing angle X-ray diffraction employed to examine the phase transformation in the oxide films showed that the addition of cerium transformed the phase from monoclinic zir...

  19. Low Temperature Constrained Sintering of Cerium Gadolinium OxideFilms for Solid Oxide Fuel Cell Applications

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas, Jason Dale [Univ. of California, Berkeley, CA (United States)

    2007-01-01

    Cerium gadolinium oxide (CGO) has been identified as an acceptable solid oxide fuel cell (SOFC) electrolyte at temperatures (500-700 C) where cheap, rigid, stainless steel interconnect substrates can be used. Unfortunately, both the high sintering temperature of pure CGO, >1200 C, and the fact that constraint during sintering often results in cracked, low density ceramic films, have complicated development of metal supported CGO SOFCs. The aim of this work was to find new sintering aids for Ce0.9Gd0.1O1.95, and to evaluate whether they could be used to produce dense, constrained Ce0.9Gd0.1O1.95 films at temperatures below 1000 C. To find the optimal sintering aid, Ce0.9Gd0.1O1.95 was doped with a variety of elements, of which lithium was found to be the most effective. Dilatometric studies indicated that by doping CGO with 3mol% lithium nitrate, it was possible to sinter pellets to a relative density of 98.5% at 800 C--a full one hundred degrees below the previous low temperature sintering record for CGO. Further, it was also found that a sintering aid's effectiveness could be explained in terms of its size, charge and high temperature mobility. A closer examination of lithium doped Ce0.9Gd0.1O1.95 indicated that lithium affects sintering by producing a Li2O-Gd2O3-CeO2 liquid at the CGO grain boundaries. Due to this liquid phase sintering, it was possible to produce dense, crack-free constrained films of CGO at the record low temperature of 950 C using cheap, colloidal spray deposition processes. This is the first time dense constrained CGO films have been produced below 1000 C and could help commercialize metal supported ceria based solid oxide fuel cells.

  20. Physical and chemical characterization of cerium(IV) oxide nanoparticles.

    Science.gov (United States)

    Cepriá, Gemma; Córdova, Walvin R; Céspedes, Oscar; Sánchez-García, Laura; Ferrer, Pilar; Gianolio, Diego; Castillo, Juan R

    2016-09-01

    Chemical composition, size and structure of the nanoparticle are required to describe nanoceria. Nanoparticles of similar size and Ce(III) content might exhibit different chemical behaviour due to their differences in structure. A simple and direct procedure based on affordable techniques for all the laboratories is presented in this paper. The combination of Raman and UV-vis spectroscopy and particle impact coulometry (PIC) allows the characterization of nanoceria of small size from 4 to 65 nm at a concentration from micromolar to nanomolar, a concentration range suitable for the analysis of lab-prepared or commercial nanoparticle suspensions, but too high for most analytical purposes aimed at nanoparticle monitoring. While the PIC limits of size detection are too high to observe small nanoparticles unless catalytic amplification is used, the method provides a simple means to study aggregation of nanoparticles in the media they are needed to be dispersed for each application. Raman spectroscopy provided information about structure of the nanoparticle, and UV-vis about their chemical behaviour against some common reducing and oxidizing agents. Graphical Abstract To characterize nanoceria it is necessary to provide information about the shape, size and structure of the nanoparticles as well as the chemical composition.

  1. Five Kilowatt Solid Oxide Fuel Cell/Diesel Reformer

    Energy Technology Data Exchange (ETDEWEB)

    Dennis Witmer; Thomas Johnson

    2008-12-31

    Reducing fossil fuel consumption both for energy security and for reduction in global greenhouse emissions has been a major goal of energy research in the US for many years. Fuel cells have been proposed as a technology that can address both these issues--as devices that convert the energy of a fuel directly into electrical energy, they offer low emissions and high efficiencies. These advantages are of particular interest to remote power users, where grid connected power is unavailable, and most electrical power comes from diesel electric generators. Diesel fuel is the fuel of choice because it can be easily transported and stored in quantities large enough to supply energy for small communities for extended periods of time. This projected aimed to demonstrate the operation of a solid oxide fuel cell on diesel fuel, and to measure the resulting efficiency. Results from this project have been somewhat encouraging, with a laboratory breadboard integration of a small scale diesel reformer and a Solid Oxide Fuel Cell demonstrated in the first 18 months of the project. This initial demonstration was conducted at INEEL in the spring of 2005 using a small scale diesel reformer provided by SOFCo and a fuel cell provided by Acumentrics. However, attempts to integrate and automate the available technology have not proved successful as yet. This is due both to the lack of movement on the fuel processing side as well as the rather poor stack lifetimes exhibited by the fuel cells. Commercial product is still unavailable, and precommercial devices are both extremely expensive and require extensive field support.

  2. Cerium-modified doped strontium titanate compositions for solid oxide fuel cell anodes and electrodes for other electrochemical devices

    Science.gov (United States)

    Marina, Olga A [Richland, WA; Stevenson, Jeffry W [Richland, WA

    2010-03-02

    The present invention provides novel compositions that find advantageous use in making electrodes for electrochemical cells and electrochemical devices such as solid oxide fuel cells, electrolyzers, sensors, pumps and the like, the compositions comprising cerium-modified doped strontium titanate. The invention also provides novel methods for making and using anode material compositions and solid oxide fuel cells and solid oxide fuel cell assemblies having anodes comprising the compositions.

  3. Comparative hazard identification of nano- and micro-sized cerium oxide particles based on 28-day inhalation studies in rats

    NARCIS (Netherlands)

    Gosens, Ilse; Mathijssen, Liesbeth E A M; Bokkers, Bas G H|info:eu-repo/dai/nl/304847062; Muijser, Hans; Cassee, Flemming R.|info:eu-repo/dai/nl/143038990

    2014-01-01

    There are many uncertainties regarding the hazard of nanosized particles compared to the bulk material of the parent chemical. Here, the authors assess the comparative hazard of two nanoscale (NM-211 and NM-212) and one microscale (NM-213) cerium oxide materials in 28-day inhalation toxicity studies

  4. Germination and early plant development of ten plant species exposed to titanium dioxide and cerium oxide nanoparticles

    Science.gov (United States)

    Ten agronomic plant species were exposed to different concentrations of nano titanium dioxide (nTiO2) or nano cerium oxide (nCeO2) (0, 250, 500 and 1000 mg/L) to examine potential effects on germination and early seedling development. We modified a standard test protocol develop...

  5. Influence of hydroxyl content of binders on rheological properties of cerium-gadolinium oxide (CGO) screen printing inks

    DEFF Research Database (Denmark)

    Marani, Debora; Gadea, Christophe; Hjelm, Johan;

    2015-01-01

    vinyl resins) were selected and characterized in solution via viscosimetry method. A high degree of hyper-entanglement was observed for ethyl cellulose polymers, whereas a mitigated effect characterized the two vinyl resins. Cerium-gadolinium oxides (CGO)-based inks, prepared using the selected binders...

  6. Structural Characteristics of Cerium Oxide Nanocrystals Prepared by the Microemulsion Method

    Institute of Scientific and Technical Information of China (English)

    J.Zhang; X.Ju; Z.Y.Wu; T.Liu; T.D.Hu; Y.N.Xie

    2001-01-01

    The aim of this work is to investigate the microstructure development of erium oxide nanocrystal,prepared by the microemulsion process,as a function of annealing temperature in air.Combined with the HRTEM and the thermogravimetric-differential thermal analysis in air.Combined withthe HRTEm and the thremogravimetric-differential thermal analysis(TG-DTA),the XRD patterns reveal that the sample annealed at 623 K is amorphous,and the formation of cerium oxide nanocrystal occurs above 773 K.The local structural and electronic properties in the nanocrystallization process are probed by X-ray absorption spectra (XAS) at the Ce L3 edge.It is found that the phase structure changes from triclinic to cubic (CeO2),and the electroic structure changes from Ce3 to Ce4 upon increasing the annealing temperature.

  7. Corrosion resistance of flaky aluminum pigment coated with cerium oxides/hydroxides in chloride and acidic electrolytes

    Science.gov (United States)

    Niroumandrad, S.; Rostami, M.; Ramezanzadeh, B.

    2015-12-01

    The objective of this study was to enhance the corrosion resistance of lamellar aluminum pigment through surface treatment by cerium oxides/hydroxides. The surface composition of the pigments was studied by energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of the pigment was evaluated by conventional hydrogen evolution measurements in acidic solution and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. Results showed that the Ce-rich coating composed of Ce2O3 and CeO2 was precipitated on the pigment surface after immersion in the cerium solution. The corrosion resistance of pigment was significantly enhanced after modification with cerium layer.

  8. Air, aqueous and thermal stabilities of Ce3+ ions in cerium oxide nanoparticle layers with substrates

    KAUST Repository

    Naganuma, Tamaki

    2014-01-01

    Abundant oxygen vacancies coexisting with Ce3+ ions in fluorite cerium oxide nanoparticles (CNPs) have the potential to enhance catalytic ability, but the ratio of unstable Ce3+ ions in CNPs is typically low. Our recent work, however, demonstrated that the abundant Ce3+ ions created in cerium oxide nanoparticle layers (CNPLs) by Ar ion irradiation were stable in air at room temperature. Ce valence states in CNPs correlate with the catalytic ability that involves redox reactions between Ce3+ and Ce4+ ions in given application environments (e.g. high temperature in carbon monoxide gas conversion and immersion conditions in biomedical applications). To better understand the mechanism by which Ce3+ ions achieve stability in CNPLs, we examined (i) extra-long air-stability, (ii) thermal stability up to 500 °C, and (iii) aqueous stability of Ce 3+ ions in water, buffer solution and cell culture medium. It is noteworthy that air-stability of Ce3+ ions in CNPLs persisted for more than 1 year. Thermal stability results showed that oxidation of Ce 3+ to Ce4+ occurred at 350 °C in air. Highly concentrated Ce3+ ions in ultra-thin CNPLs slowly oxidized in water within 1 day, but stability was improved in the cell culture medium. Ce 3+ stability of CNPLs immersed in the medium was associated with phosphorus adsorption on the Ce3+ sites. This study also illuminates the potential interaction mechanisms of stable Ce3+ ions in CNPLs. These findings could be utilized to understand catalytic mechanisms of CNPs with abundant oxygen vacancies in their application environments. © The Royal Society of Chemistry 2014.

  9. Effect of upgraded diesel fuels and oxidation catalysts on emission properties, especially PAH and genotoxicity

    DEFF Research Database (Denmark)

    Johansen, Keld; Gabrielsson, Pär; Stavnsbjerg, Peter

    1997-01-01

    Test samples of two different “advanced” diesel fuels were prepared from the raw diesel of North Sea Light Gas Oil. A commercial “Ultralight” diesel fuel was used as a reference. The three fuels were tested on two engines with and without an oxidation catalyst: 1) a VOLVO 10.0 1 DI was mounted in...

  10. Recovery Act. Solid Oxide Fuel Cell Diesel Auxilliary Power Unit Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Geiger, Gail E. [Delphi Automotive Systems, LLC., Gillingham (United Kingdom)

    2013-09-30

    Solid Oxide Fuel Cell Diesel Auxilliary Power Unit Demonstration Project. Summarizing development of Delphi’s next generation SOFC system as the core power plant to prove the viability of the market opportunity for a 3-5 kW diesel SOFC system. Report includes test and demonstration results from testing the diesel APU in a high visibility fleet customer vehicle application.

  11. Effective improvement of interface modified strontium titanate based solid oxide fuel cell anodes by infiltration with nano-sized palladium and gadolinium-doped cerium oxide

    DEFF Research Database (Denmark)

    Abdul Jabbar, Mohammed Hussain; Høgh, Jens Valdemar Thorvald; Zhang, Wei

    2013-01-01

    The development of low temperature solid oxide fuel cell (SOFC) anodes by infiltration of Pd/Gd-doped cerium oxide (CGO) electrocatalysts in Nb-doped SrTiO3 (STN) backbones has been investigated. Modification of the electrode/electrolyte interface by thin layer of spin-coated CGO (400-500 nm) con...

  12. Kinetics and Mechanism of Ruthenium(III) Catalyzed Oxidation of Butanone and Uncatalyzed Oxidation of Cychlohexanone by Cerium(IV) in Acid Sulphate Medium

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Priyamvada; Hemkar, Shalini; Khandelwal, C. L.; Sharma, P. D. [Univ. of Rajasthan, Jaipur (India)

    2012-02-15

    The kinetics of ruthenium(III) chloride catalyzed oxidation of butanone and uncatalyzed oxidation of cyclohexanone by cerium(IV) in sulphuric acid medium have been studied. The kinetic rate law(I) in case of butanone conforms to the proposed mechanism. Kinetics and activation parameters have been evaluated conventionally. Kinetically preferred mode of reaction is via ketonic and not the enolic forms.

  13. Simultaneous oxidation and adsorption of As(III) from water by cerium modified chitosan ultrafine nanobiosorbent

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lingfan [School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237 (China); Research Center of Analysis and Test, East China University of Science and Technology, Shanghai 200237 (China); Zhu, Tianyi [School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237 (China); Liu, Xin, E-mail: liuxin@ecust.edu.cn [School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhang, Wenqing, E-mail: zhwqing@ecust.edu.cn [School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2016-05-05

    Highlights: • A novel ultrafine nanobiosorbent of cerium modified chitosan (Ce-CNB) was prepared. • The Ce-CNB possessed properties for simultaneous oxidation and adsorption As(III). • Adsorption of As(III) by Ce-CNB was in high efficiency. • Mechanisms for As(III) adsorption on Ce-CNB were elucidated. - Abstract: Since most existing arsenic removal adsorbents are difficult to effectively remove arsenite (As(III)), an urgent need is to develop an efficient adsorbent for removing As(III) from contaminated water. In this study, a novel ultrafine nanobiosorbent of cerium modified chitosan (Ce-CNB) with simultaneous oxidation and adsorption As(III) performance has been successfully developed. The resulting Ce-CNB with or without As(III) adsorption was characterized by FTIR, XRD, SEM, EDS, TEM, EMI and XPS analysis. Batch of adsorption experiments were performed to investigate the effects of various conditions on the As(III) adsorption. The adsorption behaviors were well described by the Langmuir isotherm and the pseudo-second-order kinetic model, with the maximum adsorption capacities of 57.5 mg g{sup −1}. The adsorption mechanisms for As(III) were (i) formed monodentate and bidentate complexes between hydroxyl groups and arsenite; and (ii) partial As(III) oxidized to As(V) followed by simultaneously adsorbed on the surface of Ce-CNB. This novel nanocomposite can be reused while maintaining a high removal efficiency and can be applied to treat 5.8 L of As(III)-polluted water with the effluent concentration lower than the World Health Organization standard, which suggests its great potential to remove As(III) from contaminated water.

  14. Ultrastructural Analysis of Human Breast Cancer Cells during Their Overtime Interaction with Cerium Oxide Nanoparticles

    KAUST Repository

    AlAbbadi, Shatha H.

    2016-12-01

    Cerium oxide nanoparticles have been proposed as an anticancer agent, thanks to their ability of tuning the redox activity in accordance to different conditions, which lead to selective roles on healthy and cancer cells. Recent evidence suggested the ability of these nanoparticles to be toxic against cancer cells, while confer protection from oxidative stress, toward healthy cells. The main focus of this study was to determine the ultrastructural effects of cerium oxide nanoparticles over multiple incubation time of 1, 3, and 7 days on breast healthy and cancer cells. Cellular characterizations were carried out using electron microscopes, both transmission and scanning electron microscopes, while the viability assessments were performed by propidium iodide and trypan blue viability assays. The obtained results of the viability assays and electron microscopy suggested higher toxic effects on the cancer cell line viability by using a nanoceria dose of 300 μg/mL after 1 day of treatment. Such effects were shown to be preserved at 3 days, and in a longer time point of 7 days. On the contrary, the healthy cells underwent less effects on their viability at time point of 1 and 7 days. The 3 days treatment demonstrated a reduction on the number of cells that did not correlate with an increase of the dead cells, which suggested a possible initial decrease of the cell growth rate, which could be due to the high intracellular loading of nanoparticles. To conclude, the overall result of this experiment suggested that 300 μg/mL of CeO2 nanoparticles is the most suitable dose, within the range and the time point tested, which induces long-lasting cytotoxic effects in breast cancer cells, without harming the normal cells, as highlighted by the viability assays and ultrastructural characterization of electron microscopy analysis.

  15. Epitaxial growth and structure of monolayer cerium oxide films on Rh(111)

    Science.gov (United States)

    Chan, Lap Hong; Yuhara, Junji

    2017-07-01

    We prepared monolayer cerium (Ce) oxide films on Rh(111) to investigate their growth and structure using scanning tunneling microscopy (STM), low-energy electron diffraction, X-ray photoemission spectroscopy (XPS), and density functional theory (DFT) calculations. For quantitative analysis of Ce-oxide films, we used the combined techniques of XPS and Rutherford backscattering spectrometry to determine the concentration of Ce and O atoms. We prepared a monolayer (ML) Ce-oxide film by annealing a metallic Ce film at 0.3 ML coverage in an oxygen atmosphere. A well-ordered Ce-oxide phase with a (4×4) unit cell was obtained. The epitaxially grown Ce-oxide film aligned along the azimuthal direction of Rh(111). The number of Ce and O atoms in the (4×4) unit cell was estimated. The STM images indicated that the two-dimensional island growth of the p(4×4) phase with p3m1 symmetry can be explained using the missing Ce atoms model. A simulated STM image of the p(4×4) structural model was in good agreement with the experimental STM image. The formation of Ce-oxide films on Rh(111) at submonolayer coverage was discussed on the basis of the results of DFT+U calculations.

  16. Effect of cerium and lanthanum additives on plasma electrolytic oxidation of AZ31 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    沈德久; 马豪杰; 郭长虹; 蔡景瑞; 李国龙; 何东磊; 杨庆祥

    2013-01-01

    Plasma electrolytic oxidation (PEO) coatings on AZ31 magnesium (Mg) alloy were developed using the aqueous solution with alkaline silicate and sodium hydroxide as a base electrolyte system. The effects of cerium (Ce) nitrate and lanthanum (La) nitrate additives on the voltage response, microstructure, compositions and corrosion resistance of PEO coatings were investigated by scan-ning electron microscopy (SEM), energy-dispersive spectrum (EDS), X-ray diffraction (XRD) and potentiodynamic polarization tests, etc. The results showed that Ce and La additives increased the stable voltage and compactness of the PEO coatings, while, those did not change the compositions of the PEO coatings. The corrosion resistance of the PEO coating obtained in solutions with La nitrate of 0.1 g/L was the best, followed by that with Ce nitrate of 0.1 g/L and that without additives.

  17. Effect of CO2 on the Conversion of Isobutane over Iron, Cerium and Molybdenum Mixed Oxides

    Directory of Open Access Journals (Sweden)

    Daifallah Al-Dhayan

    2016-10-01

    Full Text Available A series of cerium and iron mixed oxide catalysts were prepared by thermal decomposition of Fe1.5PMo12O40 and Ce1.5PMo12O40 heteropolyanions mixture. The prepared catalysts have been characterized and tested for the conversion of isobutane in the presence of CO2. Characterization by XRD showed that besides Fe2O3 and CeO2, α-MoO3 was the main phase formed after thermal treatment. The effect of the support, the reaction temperature, and the presence of H2O in the reactant mixture was investigated. It has been found that the support enhanced both the conversion and isobutene selectivity. As for the reaction temperature and addition of water, it has been found that increasing the temperature increased both the conversion and isobutene selectivity, whereas the presence of water increased the isobutene selectivity but decreased the conversion.

  18. Catalytic ozonation of oxalate with a cerium supported palladium oxide: An efficient degradation not relying on hydroxyl radical oxidation

    KAUST Repository

    Zhang, Tao

    2011-11-01

    The cerium supported palladium oxide (PdO/CeO 2) at a low palladium loading was found very effective in catalytic ozonation of oxalate, a probe compound that is difficult to be efficiently degraded in water with hydroxyl radical oxidation and one of the major byproducts in ozonation of organic matter. The oxalate was degraded into CO 2 during the catalytic ozonation. The molar ratio of oxalate degraded to ozone consumption increased with increasing catalyst dose and decreasing ozone dosage and pH under the conditions of this study. The maximum molar ratio reached around 1, meaning that the catalyst was highly active and selective for oxalate degradation in water. The catalytic ozonation, which showed relatively stable activity, does not promote hydroxyl radical generation from ozone. Analysis with ATR-FTIR and in situ Raman spectroscopy revealed that 1) oxalate was adsorbed on CeO 2 of the catalyst forming surface complexes, and 2) O 3 was adsorbed on PdO of the catalyst and further decomposed to surface atomic oxygen (*O), surface peroxide (*O 2), and O 2 gas in sequence. The results indicate that the high activity of the catalyst is related to the synergetic function of PdO and CeO 2 in that the surface atomic oxygen readily reacts with the surface cerium-oxalate complex. This kind of catalytic ozonation would be potentially effective for the degradation of polar refractory organic pollutants and hydrophilic natural organic matter. © 2011 American Chemical Society.

  19. Label-free electrochemical immunosensor based on cerium oxide nanowires for Vibrio cholerae O1 detection

    Energy Technology Data Exchange (ETDEWEB)

    Tam, Phuong Dinh, E-mail: phuongdinhtam@gmail.com; Thang, Cao Xuan, E-mail: thang.caoxuan@hust.edu.vn

    2016-01-01

    This paper developed a label-free immunosensor based on cerium oxide nanowire for Vibrio cholerae O1 detection application. The CeO{sub 2} nanowires were synthesized by hydrothermal reaction. The immobilization of Anti-V. cholerae O1 onto CeO{sub 2} nanowire-deposited sensor was performed via an amino ester, which was created by using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, and sulfo-N-hydroxysuccinimide. The electrochemical responses of the immunosensor were studied by electrochemical impedance spectroscopy with [Fe (CN) {sub 6}] {sup 3−/4−} as redox probe. A linear response in electron transfer resistance for cell of V. cholerae O1 concentration was found in the range of 1.0 × 10{sup 2} CFU/mL to 1.0 × 10{sup 4} CFU/mL. The detection limit of the immunosensor was 1.0 × 10{sup 2} CFU/mL. The immunosensor sensitivity was 56.82 Ω/CFU·mL{sup −1}. Furthermore, the parameters affecting immunosensor response were also investigated, as follows: pH value, immunoreaction time, incubation temperature, and anti-V. cholerae O1 concentration. - Highlights: • A label-free immunosensor based on cerium oxide nanowire for Vibrio cholerae O1 detection application was developed. • A linear response was found in the range of 1.0 × 10{sup 2} CFU/mL to 1.0 × 10{sup 4} CFU/mL. • The detection limit of the immunosensor was 1.0 × 10{sup 2} CFU/mL. • The immunosensor sensitivity was 56.82 Ω/CFU.mL{sup −1}.

  20. Cerium oxide dispersed multi walled carbon nanotubes as cathode material for flexible field emitters.

    Science.gov (United States)

    Baby, Tessy Theres; Rakhi, R B; Ravi, N; Ramaprabhu, S

    2012-08-01

    Nanomaterials based electron sources are omnipresent in modern flat panel displays. Multi walled carbon nanotubes (MWNT) are the well studied electron emitter among the carbon materials. Since the surface modification of MWNT with low work function materials would have a positive impact on the field emission property of MWNT, cerium oxide (CeO2) nanoparticles dispersed multi walled carbon nanotubes (CeO2/MWNT) were synthesized by catalytic chemical vapour deposition followed by chemical reduction and its field emission property was investigated. The high-purity MWNT as well as CeO2/MWNT showed crystalline structure conformed by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Further characterisation was done with Raman spectroscopy, UV-Visible absorption spectra and Fourier transform IR spectroscopy (FT-IR). The morphology and structural details of CeO2/MWNT composite was probed by field-emission scanning electron microscopy (FESEM) and energy dispersive X-ray analysis (EDX). The direct evidence of the formation of CeO2/MWNT composites was given by transmission electron microscopy (TEM). The synthesized sample was coated over a flexible carbon paper using spin coating technique. The experiment was performed under a vacuum of 1 x 10(-6) Torr and Fowler-Nordheim equation was used to analyse the data. The turn-on voltage for the cerium oxide dispersed MWNT was found for a current density of 10 microA/cm2. The emission current density from the CeO2 nanoparticles dispersed MWNT reached 0.2 mA/cm2 at a reasonable bias field of 2.58 V/microm. The results were compared with those of pure MWNT and pure CeO2 nanoparticles with literature values.

  1. Cerium oxide nanoparticles inhibit the migration and proliferation of gastric cancer by increasing DHX15 expression

    Directory of Open Access Journals (Sweden)

    Xiao YF

    2016-07-01

    Full Text Available Yu-Feng Xiao,1 Jian-Mei Li,2 Su-Min Wang,1 Xin Yong,1 Bo Tang,1 Meng-Meng Jie,1 Hui Dong,1 Xiao-Chao Yang,2 Shi-Ming Yang1 1Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, People’s Republic of China; 2School of Biomedical Engineering, Third Military Medical University, Chongqing, People’s Republic of China Abstract: Gastric cancer is one of the leading causes of tumor-related deaths in the world. Current treatment options do not satisfy doctors and patients, and new therapies are therefore needed. Cerium oxide nanoparticles (CNPs have been studied as a potential therapeutic approach for treating many diseases. However, their effects on human gastric cancer are currently unknown. Therefore, in this study, we aimed to characterize the effects of CNPs on human gastric cancer cell lines (MKN28 and BGC823. Gastric cancer cells were cocultured with different concentrations of CNPs, and proliferation and migration were measured both in vitro and in vivo. We found that CNPs inhibited the migration of gastric cancer cells when applied at different concentrations, but only a relatively high concentration (10 µg/mL of CNPs suppressed proliferation. Furthermore, we found that CNPs increased the expression of DHX15 and its downstream signaling pathways. We therefore provide evidence showing that CNPs may be a promising approach to suppress malignant activity of gastric cancer by increasing the expression of DHX15. Keywords: cerium oxide nanoparticles, gastric cancer, DHX15, p38

  2. Testing of a Catalytic Partial Oxidation Diesel Reformer with a Solid Oxide Fuel Cell System

    Energy Technology Data Exchange (ETDEWEB)

    Lyman Frost; Bob Carrington; Rodger McKain; Dennis Witmer

    2005-03-01

    Rural Alaska currently uses diesel generator sets to produce much of its power. The high energy content of diesel (i.e. ~140,000 BTU per gallon) makes it the fuel of choice because this reduces the volume of fuel that must be transported, stored, and consumed in generating the power. There is an existing investment in infrastructure for the distribution and use of diesel fuel. Problems do exist, however, in that diesel generators are not very efficient in their use of diesel, maintenance levels can be rather high as systems age, and the environmental issues related to present diesel generators are of concern. The Arctic Energy Technology Development Laboratory at the University of Alaska -- Fairbanks is sponsoring a project to address the issues mentioned above. The project takes two successful systems, a diesel reformer and a tubular solid oxide fuel cell unit, and jointly tests those systems with the objective of producing a for-purpose diesel fueled solid oxide fuel cell system that can be deployed in rural Alaska. The reformer will convert the diesel to a mixture of carbon monoxide and hydrogen that can be used as a fuel by the fuel cell. The high temperature nature of the solid oxide fuel cell (SOFC is capable of using this mixture to generate electricity and provide usable heat with higher efficiency and lower emissions. The high temperature nature of the SOFC is more compatible with the arctic climate than are low temperature technologies such as the proton exchange membrane fuel cells. This paper will look at the interaction of a SOFC system that is designed to internally reform methane and a catalytic partial oxidation (CPOX) diesel reformer. The diesel reformer produces a reformate that is approximately 140 BTU per scf (after removal of much of the reformate water) as compared to a methane based reformate that is over twice that value in BTU content. The project also considers the effect of altitude since the test location will be at 4800 feet with the

  3. Recent advances of cerium oxide nanoparticles in synthesis, luminescence and biomedical studies:a review

    Institute of Scientific and Technical Information of China (English)

    何立莹; 苏玉民; 蒋兰宏; 石士考

    2015-01-01

    Nanostructured cerium oxide (CeO2) commonly known as nanoceria is a rare earth metal oxide, which plays a technologi-cally important role due to its versatile applications as automobile exhaust catalysts, oxide ion conductors in solid oxide fuel cells, electrode materials for gas sensors, ultraviolet absorbents and glass-polishing materials. However, nanoceria has little or weak lumi-nescence, and therefore its uses in high-performance luminescent devices and biomedical areas are limited. In this review, we present the recent advances of nanoceria in the aspects of synthesis, luminescence and biomedical studies. The CeO2 nanoparticles can be synthesized by solution-based methods including co-precipitation, hydrothermal, microemulsion process, sol-gel techniques, combus-tion reaction and so on. Achieving controlled morphologies and enhanced luminescence efficiency of nanoceria particles are quite es-sential for its potential energy- and environment-related applications. Additionally, a new frontier for nanoceria particles in biomedi-cal research has also been opened, which involves low toxicity, retinopathy, biosensors and cancer therapy aspects. Finally, the sum-mary and outlook on the challenges and perspectives of the nanoceria particles are proposed.

  4. Effects of acetic acid on microstructure and electrochemical properties of nano cerium oxide films coated on AA7020-T6 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    H. Hasannejad; T. Shahrabi; M. Aliofkhazraei

    2009-01-01

    Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD), crack-flee films with well-developed grains were obtained and grain sizes of the films decreased. Elimination of cracks and decreasing grain size of the nano cerium oxide films caused corrosion resistance to increase.

  5. Reaction chemistry of cerium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    It is truly ironic that a synthetic organic chemist likely has far greater knowledge of the reaction chemistry of cerium(IV) than an inorganic colleague. Cerium(IV) reagents have long since been employed as oxidants in effecting a wide variety of organic transformations. Conversely, prior to the late 1980s, the number of well characterized cerium(IV) complexes did not extend past a handful of known species. Though in many other areas, interest in the molecular chemistry of the 4f-elements has undergone an explosive growth over the last twenty years, the chemistry of cerium(IV) has for the most part been overlooked. This report describes reactions of cerium complexes and structure.

  6. Reaction chemistry of cerium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    It is truly ironic that a synthetic organic chemist likely has far greater knowledge of the reaction chemistry of cerium(IV) than an inorganic colleague. Cerium(IV) reagents have long since been employed as oxidants in effecting a wide variety of organic transformations. Conversely, prior to the late 1980s, the number of well characterized cerium(IV) complexes did not extend past a handful of known species. Though in many other areas, interest in the molecular chemistry of the 4f-elements has undergone an explosive growth over the last twenty years, the chemistry of cerium(IV) has for the most part been overlooked. This report describes reactions of cerium complexes and structure.

  7. Influence of agglomeration of cerium oxide nanoparticles and speciation of cerium(III) on short term effects to the green algae Chlamydomonas reinhardtii

    Energy Technology Data Exchange (ETDEWEB)

    Röhder, Lena A. [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, Dübendorf 8600 (Switzerland); ETH-Zurich, Institute of Biogeochemistry and Pollutant Dynamics, Zürich 8092 (Switzerland); Brandt, Tanja [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, Dübendorf 8600 (Switzerland); Sigg, Laura [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, Dübendorf 8600 (Switzerland); ETH-Zurich, Institute of Biogeochemistry and Pollutant Dynamics, Zürich 8092 (Switzerland); Behra, Renata, E-mail: Renata.behra@eawag.ch [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, Dübendorf 8600 (Switzerland)

    2014-07-01

    Highlights: • Phosphate-dispersed CeO₂ NP did not affect photosynthetic yield in C. reinhardtii. • Agglomerated CeO₂ NP slightly decreased photosynthetic yield. • Cerium(III) was shown to affect photosynthetic yield and intracellular ROS level. • Slight effects of CeO₂ NP were caused by dissolved Ce³⁺ ions present in suspensions. • Wild type and cell wall free mutant of C. reinhardtii showed the same sensitivity. - Abstract: Cerium oxide nanoparticles (CeO₂ NP) are increasingly used in industrial applications and may be released to the aquatic environment. The fate of CeO₂ NP and effects on algae are largely unknown. In this study, the short term effects of CeO₂ NP in two different agglomeration states on the green algae Chlamydomonas reinhardtii were examined. The role of dissolved cerium(III) on toxicity, its speciation and the dissolution of CeO₂ NP were considered. The role of cell wall of C. reinhardtii as a barrier and its influence on the sensitivity to CeO₂ NP and cerium(III) was evaluated by testing both, the wild type and the cell wall free mutant of C. reinhardtii. Characterization showed that CeO₂ NP had a surface charge of ~0 mV at physiological pH and agglomerated in exposure media. Phosphate stabilized CeO₂ NP at pH 7.5 over 24 h. This effect was exploited to test CeO₂ NP dispersed in phosphate with a mean size of 140 nm and agglomerated in absence of phosphate with a mean size of 2000 nm. The level of dissolved cerium(III) in CeO₂ NP suspensions was very low and between 0.1 and 27 nM in all tested media. Exposure of C. reinhardtii to Ce(NO₃)₃ decreased the photosynthetic yield in a concentration dependent manner with EC₅₀ of 7.5 ± 0.84 μM for wild type and EC₅₀ of 6.3 ± 0.53 μM for the cell wall free mutant. The intracellular level of reactive oxygen species (ROS) increased upon exposure to Ce(NO₃)₃ with effective concentrations similar to those inhibiting photosynthesis. The agglomerated Ce

  8. Cerium Oxide Nanoparticles Decorated Graphene Nanosheets for Selective Detection of Dopamine.

    Science.gov (United States)

    Nayak, Pranati; Santhosh, P N; Ramaprabhu, S

    2015-07-01

    The fabrication of a novel amperometric biosensor based on selective determination of dopamine (DA) using nafion coated cerium oxide nanoparticles (NPs) decorated graphene nanosheets (CeO2-HEG-nafion) as a transducer candidate is reported. Graphene was synthesized by hydrogen exfoliation technique. Decoration of CeO2NPs over graphene nanosheets was done by chemical reduction method. The electrochemical impedance spectroscopy (EIS) study shows the enhanced electron transfer kinetics of the composite compared to HEG modified and bare glassy carbon electrode (GCE). The response of the composite towards dopamine displays a lower oxidation potential of 0.23 V and a high oxidation current. The sensor exhibits linearity from 10 µM to 780 µM with a detection limit of 1 µM. In the presence of nafion, it shows excellent selectivity for coexisting interference species like Ascorbic acid (AA) and Uric acid (UA). The excellent performance of the biosensor can be attributed to large active surface area, enhanced electron transfer kinetics and high catalytic activity of the composite.

  9. Cytotoxicity and antibacterial activity of gold-supported cerium oxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Suresh Babu K

    2014-11-01

    Full Text Available K Suresh Babu,1,† M Anandkumar,1,† TY Tsai,2 TH Kao,2 B Stephen Inbaraj,2 BH Chen2,31Centre for Nano Sciences and Technology, Madanjeet School of Green Energy Technologies, Pondicherry University, Kalapet, India; 2Department of Food Science, 3Graduate Institute of Medicine, Fu Jen University, Taipei, Taiwan†These authors contributed equally to this workBackground: Cerium oxide nanoparticles (CeO2 have been shown to be a novel therapeutic in many biomedical applications. Gold (Au nanoparticles have also attracted widespread interest due to their chemical stability and unique optical properties. Thus, decorating Au on CeO2 nanoparticles would have potential for exploitation in the biomedical field. Methods: In the present work, CeO2 nanoparticles synthesized by a chemical combustion method were supported with 3.5% Au (Au/CeO2 by a deposition-precipitation method. The as-synthesized Au, CeO2, and Au/CeO2 nanoparticles were evaluated for antibacterial activity and cytotoxicity in RAW 264.7 normal cells and A549 lung cancer cells. Results: The as-synthesized nanoparticles were characterized by X-ray diffraction, scanning and transmission electron microscopy, and ultraviolet-visible measurements. The X-ray diffraction study confirmed the formation of cubic fluorite-structured CeO2 nanoparticles with a size of 10 nm. All synthesized nanoparticles were nontoxic towards RAW 264.7 cells at doses of 0–1,000 µM except for Au at >100 µM. For A549 cancer cells, Au/CeO2 had the highest inhibitory effect, followed by both Au and CeO2 which showed a similar effect at 500 and 1,000 µM. Initial binding of nanoparticles occurred through localized positively charged sites in A549 cells as shown by a shift in zeta potential from positive to negative after 24 hours of incubation. A dose-dependent elevation in reactive oxygen species indicated that the pro-oxidant activity of the nanoparticles was responsible for their cytotoxicity towards A549 cells. In

  10. Preparation and properties of a cerium-containing hydroxyapatite coating on commercially pure titanium by micro-arc oxidation

    Institute of Scientific and Technical Information of China (English)

    HUANG Yong; WANG Yingjun; NING Chengyun; NAN Kaihui; HAN Yong

    2008-01-01

    A porous cerium-containing hydroxyapatite coating on commercially pure titanium was prepared by micro-arc oxidation (MAO) in an electrolytic solution containing calcium acetate, β-glycerol phosphate disodium salt pentahydrate (β-GP), and cerium nitrate. The thickness, phase, composition morphology, and biocompatibility of the oxide coating were characterized by X-ray diffraction (XRD), electron probe microanalysis (EPMA), scanning electron microscopy (SEM) with energy dispersive X-ray spectrometer (EDS), and cell culture. The thickness of the MAO film is about 15-25μm, and the coating is porous and uneven, without any apparent interface to the titanium substrates. The results of XRD and EDS show that the porous coating is made up of hydroxyapatite (HA) film containing Ce. The favorable osteoblast cell affinity makes the Ce-HA film have a good biocompatibility. The Ce-HA film is expected to have significant medical applications as dental implants and artificial bone joints.

  11. Mixtures of room temperature ionic liquid/ethanol solutions as electrolytic media for cerium oxide thin layer electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Lair, V., E-mail: virginie-lair@chimie-paristech.f [Laboratoire d' Electrochimie, Chimie des Interfaces et Modelisation pour l' Energie, LECIME, CNRS UMR 7575-Chimie Paristech (ENSCP)-Paris, 11, rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France); Sirieix-Plenet, J.; Gaillon, L.; Rizzi, C. [UPMC University Paris 06, UMR 7195, Laboratoire de Physicochimie des Electrolytes, Colloides et Sciences Analytiques (PECSA), F-75005 Paris (France); CNRS, UMR 7195, PECSA, F-75005 Paris (France); ESPCI, UMR 7195, PECSA, F-75005 Paris (France); Ringuede, A. [Laboratoire d' Electrochimie, Chimie des Interfaces et Modelisation pour l' Energie, LECIME, CNRS UMR 7575-Chimie Paristech (ENSCP)-Paris, 11, rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France)

    2010-12-30

    A cerium oxide thin layer was electrodeposited onto stainless steel, using mixed room temperature ionic liquid (the 1-methyl-3-butylimidazolium bis(trifluoromethyl sulfonyl)imide)/ethanol solutions, as electrolytic medium. The hydrophobic ionic liquid content is one of the main parameters in the morphology control influencing the ceria growth rate and crystallinity. Micro-nano structural properties and electrical behaviour are presented, using XRD, SEM/EDS and impedance spectroscopy, as a function of electrodeposition conditions.

  12. Preparation and Defluorination Performance of Activated Cerium(IV) Oxide/SiMCM-41 Adsorbent in Water.

    Science.gov (United States)

    Xu, Ying-Ming; Ning, An-Rong; Zhao, Jing

    2001-03-01

    By using the wetness impregnation-coprecipitation method, a new adsorbent, cerium(IV) oxide coated on SiMCM-41 ((Ce)SiMCM-41), was prepared for removal of fluoride ions from water. Factors investigated were number of impregnations, Ce/Si ratios, concentrations of F(-) ions, pH values, and calcination temperatures. The dynamics, isotherms, and mechanism of adsorption of F(-) ions were discussed. Copyright 2001 Academic Press.

  13. Potential for recovery of cerium contained in automotive catalytic converters

    Science.gov (United States)

    Bleiwas, Donald I.

    2013-01-01

    Catalytic converters (CATCONs) are required by Federal law to be installed in nearly all gasoline- and diesel-fueled onroad vehicles used in the United States. About 85 percent of the light-duty vehicles and trucks manufactured worldwide are equipped with CATCONs. Portions of the CATCONs (called monoliths) are recycled for their platinum-group metal (PGM) content and for the value of the stainless steel they contain. The cerium contained in the monoliths, however, is disposed of along with the slag produced from the recycling process. Although there is some smelter capacity in the United States to treat the monoliths in order to recover the PGMs, a great percentage of monoliths is exported to Europe and South Africa for recycling, and a lesser amount is exported to Japan. There is presently no commercial-scale capacity in place domestically to recover cerium from the monoliths. Recycling of cerium or cerium compounds from the monoliths could help ensure against possible global supply shortages by increasing the amount that is available in the supply chain as well as the number and geographic distribution of the suppliers. It could also reduce the amount of material that goes into landfills. Also, the additional supply could lower the price of the commodity. This report analyzes how much cerium oxide is contained in CATCONs and how much could be recovered from used CATCONs.

  14. Evaluation of cerium oxide coated Cu cermets as inert anodes for aluminum electrowinning

    Energy Technology Data Exchange (ETDEWEB)

    1992-08-01

    Cu/NiFe{sub 2}O{sub 4} cermets were evaluated, with and without an in-situ deposited CEROX (TM; cerium oxide) coating, in 100 h laboratory A1 electrowinning tests. Bath ratio and current density were varied between tests and corrosion was determined by contamination of the aluminum and cryolite by cermet components (Cu, Fe, and Ni). Higher bath ratios of 1.5 to 1.6 led to less corrosion and thicker CEROX coatings. Lower current densities led to slightly less corrosion but much less oxidation of the Cu cermet substrate. At identical test conditions, the corrosion of the CEROX coated cermets was 1/7 that of an uncoated cermet. Corrosion was increased in CEROX coated cermets tested under unsaturated alumina conditions. The electrical conductivity of the CEROX coating was measured to be {approximately}0.2 ohm{sup {minus}1}cm{sup {minus}1}, resulting in a slight voltage penalty, depending on the thickness of the coating.

  15. Preparation and Biocompatible Surface Modification of Redox Altered Cerium Oxide Nanoparticle Promising for Nanobiology and Medicine

    KAUST Repository

    Nanda, Himansu

    2016-11-03

    The biocompatible surface modification of metal oxide nanoparticles via surface functionalization technique has been used as an important tool in nanotechnology and medicine. In this report, we have prepared aqueous dispersible, trivalent metal ion (samarium)-doped cerium oxide nanoparticles (SmCNPs) as model redox altered CNPs of biological relevance. SmCNP surface modified with hydrophilic biocompatible (6-{2-[2-(2-methoxy-ethoxy)-ethoxy]-ethoxy}-hexyl) triethoxysilane (MEEETES) were prepared using ammonia-induced ethylene glycol-assisted precipitation method and were characterized using a variety of complementary characterization techniques. The chemical interaction of functional moieties with the surface of doped nanoparticle was studied using powerful 13C cross polarization magic angle sample spinning nuclear magnetic resonance spectroscopy. The results demonstrated the production of the extremely small size MEEETES surface modified doped nanoparticles with significant reduction in aggregation compared to their unmodified state. Moreover, the functional moieties had strong chemical interaction with the surface of the doped nanoparticles. The biocompatible surface modification using MEEETES should also be extended to several other transition metal ion doped and co-doped CNPs for the production of aqueous dispersible redox altered CNPs that are promising for nanobiology and medicine.

  16. Gold-supported cerium-doped NiOx catalysts for water oxidation

    Science.gov (United States)

    Ng, Jia Wei Desmond; García-Melchor, Max; Bajdich, Michal; Chakthranont, Pongkarn; Kirk, Charlotte; Vojvodic, Aleksandra; Jaramillo, Thomas F.

    2016-05-01

    The development of high-performance catalysts for the oxygen-evolution reaction (OER) is paramount for cost-effective conversion of renewable electricity to fuels and chemicals. Here we report the significant enhancement of the OER activity of electrodeposited NiOx films resulting from the combined effects of using cerium as a dopant and gold as a metal support. This NiCeOx-Au catalyst delivers high OER activity in alkaline media, and is among the most active OER electrocatalysts yet reported. On the basis of experimental observations and theoretical modelling, we ascribe the activity to a combination of electronic, geometric and support effects, where highly active under-coordinated sites at the oxide support interface are modified by the local chemical binding environment and by doping the host Ni oxide with Ce. The NiCeOx-Au catalyst is further demonstrated in a device context by pairing it with a nickel-molybdenum hydrogen evolution catalyst in a water electrolyser, which delivers 50 mA consistently at 1.5 V over 24 h of continuous operation.

  17. A nanostructured cerium oxide film-based immunosensor for mycotoxin detection

    Science.gov (United States)

    Kaushik, Ajeet; Rathee Solanki, Pratima; Ansari, Anees Ahmad; Ahmad, Sharif; Dhar Malhotra, Bansi

    2009-02-01

    Rabbit-immunoglobulin antibodies (r-IgGs) and bovine serum albumin (BSA) have been immobilized onto sol-gel-derived nanostructured cerium oxide (nanoCeO2) film fabricated onto an indium-tin-oxide (ITO) coated glass plate to detect ochratoxin-A (OTA). Broad reflection planes obtained in x-ray diffraction (XRD) patterns reveal the formation of CeO2 nanostructures. Electrochemical studies reveal that nanoCeO2 particles provide an increased electroactive surface area for loading of r-IgGs with desired orientation, resulting in enhanced electron communication between r-IgGs and electrode. BSA/r-IgGs/nano CeO2/ITO immunoelectrode exhibits improved characteristics such as linear range (0.5-6 ng dl-1), low detection limit (0.25 ng dl-1), fast response time (30 s) and high sensitivity (1.27 µA ng-1 dl-1 cm-2). The high value of the association constant (Ka, 0.9 × 1011 l mol-1) indicates the high affinity of the BSA/r-IgGs/nanoCeO2/ITO immunoelectrode to OTA.

  18. Preparation and Biocompatible Surface Modification of Redox Altered Cerium Oxide Nanoparticle Promising for Nanobiology and Medicine

    Directory of Open Access Journals (Sweden)

    Himansu Sekhar Nanda

    2016-11-01

    Full Text Available The biocompatible surface modification of metal oxide nanoparticles via surface functionalization technique has been used as an important tool in nanotechnology and medicine. In this report, we have prepared aqueous dispersible, trivalent metal ion (samarium-doped cerium oxide nanoparticles (SmCNPs as model redox altered CNPs of biological relevance. SmCNP surface modified with hydrophilic biocompatible (6-{2-[2-(2-methoxy-ethoxy-ethoxy]-ethoxy}-hexyl triethoxysilane (MEEETES were prepared using ammonia-induced ethylene glycol-assisted precipitation method and were characterized using a variety of complementary characterization techniques. The chemical interaction of functional moieties with the surface of doped nanoparticle was studied using powerful 13C cross polarization magic angle sample spinning nuclear magnetic resonance spectroscopy. The results demonstrated the production of the extremely small size MEEETES surface modified doped nanoparticles with significant reduction in aggregation compared to their unmodified state. Moreover, the functional moieties had strong chemical interaction with the surface of the doped nanoparticles. The biocompatible surface modification using MEEETES should also be extended to several other transition metal ion doped and co-doped CNPs for the production of aqueous dispersible redox altered CNPs that are promising for nanobiology and medicine.

  19. Simultaneous oxidation and adsorption of As(III) from water by cerium modified chitosan ultrafine nanobiosorbent.

    Science.gov (United States)

    Zhang, Lingfan; Zhu, Tianyi; Liu, Xin; Zhang, Wenqing

    2016-05-05

    Since most existing arsenic removal adsorbents are difficult to effectively remove arsenite (As(III)), an urgent need is to develop an efficient adsorbent for removing As(III) from contaminated water. In this study, a novel ultrafine nanobiosorbent of cerium modified chitosan (Ce-CNB) with simultaneous oxidation and adsorption As(III) performance has been successfully developed. The resulting Ce-CNB with or without As(III) adsorption was characterized by FTIR, XRD, SEM, EDS, TEM, EMI and XPS analysis. Batch of adsorption experiments were performed to investigate the effects of various conditions on the As(III) adsorption. The adsorption behaviors were well described by the Langmuir isotherm and the pseudo-second-order kinetic model, with the maximum adsorption capacities of 57.5 mg g(-1). The adsorption mechanisms for As(III) were (i) formed monodentate and bidentate complexes between hydroxyl groups and arsenite; and (ii) partial As(III) oxidized to As(V) followed by simultaneously adsorbed on the surface of Ce-CNB. This novel nanocomposite can be reused while maintaining a high removal efficiency and can be applied to treat 5.8L of As(III)-polluted water with the effluent concentration lower than the World Health Organization standard, which suggests its great potential to remove As(III) from contaminated water.

  20. Interactive effect of cerium and aluminum on the ignition point and the oxidation resistance of magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lin Pengyu [Key Laboratory of Automobile Materials of Ministry of Education, School of Materials Science and Engineering, Nanling Campus of Jilin University, Changchun Jilin 130025 (China)], E-mail: linpengyu2000@yahoo.com.cn; Zhou Hong; Li Wei; Li Wenping; Sun Na [Key Laboratory of Automobile Materials of Ministry of Education, School of Materials Science and Engineering, Nanling Campus of Jilin University, Changchun Jilin 130025 (China); Yang Rong [Public Mathematics Teaching and Research Center, College of Mathematics, Qianwei Campus of Jilin University, Changchun Jilin 130012 (China)

    2008-09-15

    This paper focused on the interactive effect of cerium (Ce) addition and aluminum (Al) content in magnesium alloy on ignition point and oxidation resistance. Ce content played an important role in improving the oxidation resistance of Mg alloy. Ignition point ascended with increasing Ce content. 0.25 wt% Ce content in Mg alloys could greatly improve tightness of the oxide film of Mg alloys. However, when Ce content in the alloy exceeded its solid solubility, ignition point descended. Furthermore, Al content in the alloy also influenced the ignition point. The higher the Al content was, the lower the ignition point.

  1. Freshwater dispersion stability of PAA-stabilised cerium oxide nanoparticles and toxicity towards Pseudokirchneriella subcapitata

    Energy Technology Data Exchange (ETDEWEB)

    Booth, Andy, E-mail: andy.booth@sintef.no [SINTEF Materials and Chemistry, Trondheim N-7465 (Norway); Størseth, Trond [SINTEF Materials and Chemistry, Trondheim N-7465 (Norway); Altin, Dag [BioTrix, Trondheim N-7022 (Norway); Fornara, Andrea; Ahniyaz, Anwar [German Federal Institute for Risk Assessment (BfR), Department of Product Safety, Berlin (Germany); Jungnickel, Harald; Laux, Peter; Luch, Andreas [SP Chemistry, Materials and Surfaces, Drottning Kristinas vag 45, SE-11686 Stockholm (Sweden); Sørensen, Lisbet [SINTEF Materials and Chemistry, Trondheim N-7465 (Norway)

    2015-02-01

    An aqueous dispersion of poly (acrylic acid)-stabilised cerium oxide (CeO{sub 2}) nanoparticles (PAA-CeO{sub 2}) was evaluated for its stability in a range of freshwater ecotoxicity media (MHRW, TG 201 and M7), with and without natural organic matter (NOM). In a 15 day dispersion stability study, PAA-CeO{sub 2} did not undergo significant aggregation in any media type. Zeta potential varied between media types and was influenced by PAA-CeO{sub 2} concentration, but remained constant over 15 days. NOM had no influence on PAA-CeO{sub 2} aggregation or zeta potential. The ecotoxicity of the PAA-CeO{sub 2} dispersion was investigated in 72 h algal growth inhibition tests using the freshwater microalgae Pseudokirchneriella subcapitata. PAA-CeO{sub 2} EC{sub 50} values for growth inhibition (GI; 0.024 mg/L) were 2–3 orders of magnitude lower than pristine CeO{sub 2} EC{sub 50} values reported in the literature. The concentration of dissolved cerium (Ce{sup 3+}/Ce{sup 4+}) in PAA-CeO{sub 2} exposure suspensions was very low, ranging between 0.5 and 5.6 μg/L. Free PAA concentration in the exposure solutions (0.0096–0.0384 mg/L) was significantly lower than the EC{sub 10} growth inhibition (47.7 mg/L) value of pure PAA, indicating that free PAA did not contribute to the observed toxicity. Elemental analysis indicated that up to 38% of the total Cerium becomes directly associated with the algal cells during the 72 h exposure. TOF-SIMS analysis of algal cell wall compounds indicated three different modes of action, including a significant oxidative stress response to PAA-CeO{sub 2} exposure. In contrast to pristine CeO{sub 2} nanoparticles, which rapidly aggregate in standard ecotoxicity media, PAA-stabilised CeO{sub 2} nanoparticles remain dispersed and available to water column species. Interaction of PAA with cell wall components, which could be responsible for the observed biomarker alterations, could not be excluded. This study indicates that the increased

  2. Cerium dioxide nanoparticle exposure improves microvascular dysfunction and reduces oxidative stress in spontaneously hypertensive rats

    Directory of Open Access Journals (Sweden)

    Valerie C Minarchick

    2015-11-01

    Full Text Available The elevated production of reactive oxygen species (ROS in the vascular wall is associated with cardiovascular diseases such as hypertension. This increase in oxidative stress contributes to various mechanisms of vascular dysfunction, such as decreased nitric oxide bioavailability. Therefore, anti-oxidants are being researched to decrease the high levels of ROS, which could improve the microvascular dysfunction associated with various cardiovascular diseases. From a therapeutic perspective, cerium dioxide nanoparticles (CeO2 NP hold great anti-oxidant potential, but their in vivo activity is unclear. Due to this potential anti-oxidant action, we hypothesize that injected CeO2 NP would decrease microvascular dysfunction and oxidative stress associated with hypertension. In order to simulate a therapeutic application, spontaneously hypertensive (SH and Wistar-Kyoto (WKY rats were intravenously injected with either saline or CeO2 NP (100 µg suspended in saline. Twenty-four hours post-exposure mesenteric arteriolar reactivity was assessed via intravital microscopy. Endothelium-dependent and –independent function was assessed via acetylcholine and sodium nitroprusside. Microvascular oxidative stress was analyzed using fluorescent staining in isolated mesenteric arterioles. Finally, systemic inflammation was examined using a multiplex analysis and venular leukocyte flux was counted. Endothelium-dependent dilation was significantly decreased in the SH rats (29.68 ± 3.28%, maximal response and this microvascular dysfunction was significantly improved following CeO2 NP exposure (43.76 ± 4.33%, maximal response. There was also an increase in oxidative stress in the SH rats, which was abolished following CeO2 NP treatment. These results provided evidence that CeO2 NP act as an anti-oxidant in vivo. There were also changes in the inflammatory profile in the WKY and SH rats. In WKY rats, IL-10 and TNF-α were increased following CeO2 NP treatment

  3. Attempts to minimize nitrogen oxide emission from diesel engine by using antioxidant-treated diesel-biodiesel blend.

    Science.gov (United States)

    Rashedul, Hasan Khondakar; Kalam, Md Abdul; Masjuki, Haji Hassan; Teoh, Yew Heng; How, Heoy Geok; Monirul, Islam Mohammad; Imdadul, Hassan Kazi

    2017-02-23

    The study represents a comprehensive analysis of engine exhaust emission variation from a compression ignition (CI) diesel engine fueled with diesel-biodiesel blends. Biodiesel used in this investigation was produced through transesterification procedure from Moringa oleifera oil. A single cylinder, four-stroke, water-cooled, naturally aspirated diesel engine was used for this purpose. The pollutants from the exhaust of the engine that are monitored in this study are nitrogen oxide (NO), carbon monoxide (CO), hydrocarbon (HC), and smoke opacity. Engine combustion and performance parameters are also measured together with exhaust emission data. Some researchers have reported that the reason for higher NO emission of biodiesel is higher prompt NO formation. The use of antioxidant-treated biodiesel in a diesel engine is a promising approach because antioxidants reduce the formation of free radicals, which are responsible for the formation of prompt NO during combustion. Two different antioxidant additives namely 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (MBEBP) were individually dissolved at a concentration of 1% by volume in MB30 (30% moringa biodiesel with 70% diesel) fuel blend to investigate and compare NO as well as other emissions. The result shows that both antioxidants reduced NO emission significantly; however, HC, CO, and smoke were found slightly higher compared to pure biodiesel blends, but not more than the baseline fuel diesel. The result also shows that both antioxidants were quite effective in reducing peak heat release rate (HRR) and brake-specific fuel consumption (BSFC) as well as improving brake thermal efficiency (BTE) and oxidation stability. Based on this study, antioxidant-treated M. oleifera biodiesel blend (MB30) can be used as a very promising alternative source of fuel in diesel engine without any modifications.

  4. Deep desulfurization of diesel fuels by catalytic oxidation

    Institute of Scientific and Technical Information of China (English)

    YU Guoxian; CHEN Hui; LU Shanxiang; ZHU Zhongnan

    2007-01-01

    Reaction feed was prepared by dissolving dibenzothiophene (DBT),which was selected as a model organosulfur compound in diesel fuels,in n-octane.The oxidant was a 30 wt-% aqueous solution of hydrogen peroxide.Catalytic performance of the activated carbons with saturation adsorption of DBT was investigated in the presence of formic acid.In addition,the effects of activated carbon dosage,formic acid concentration,initial concentration of hydrogen peroxide,initial concentration of DBT and reaction temperature on the oxidation of DBT were investigated.Experimental results indicated that performic acid and the hydroxyl radicals produced are coupled to oxidize DBT with a conversion ratio of 100%.Catalytic performance of the combination of activated carbon and formic acid is higher than that ofouly formic acid.The concentration of formic acid,activated carbon dosage,initial concentration of hydrogen peroxide and reaction temperature affect the oxidative removal of DBT.The higher the initial concentration of DBT in the n-octane solution,the more difficult the deep desulfurization by oxidation is.

  5. Characterization of microstructure and catalytic of cerium oxide obtained by colloidal solution; Caracterizacao da microestrutura e da atividade catalitica de oxido de cerio obtido por solucao coloidal

    Energy Technology Data Exchange (ETDEWEB)

    Senisse, C.A.L.; Bergmann, C.P.; Alves, A.K., E-mail: carolinasenisse@hotmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alege, RS (Brazil). Lab. de Materiais Ceramicos

    2012-07-01

    This study investigated to obtain particles of cerium oxide, for use as catalysts for the combustion of methane using the technique of through polymeric colloidal solution. Obtaining the colloidal system is based on hydrolysis of salts such as cerium acetylacetonate, cerium nitrate in the presence of additives such as polyvinylbutyral (PVB), polyvinylpyrrolidone (PVP) and polyvinyl acetate (PVA), at concentrations of 5, 10 and 15% in aqueous or alcoholic medium. These solutions containing ions of interest were subjected to a heat treatment at 650° C for 30 minutes, with heating rate of 2 ° C/ min. After heat treatment, the fibers were characterized according to their morphology, surface area, crystallinity, weight loss and catalytic activity. Samples obtained from cerium acetylacetonate were more reactive than the cerium nitrate to the combustion of methane, as showed greater conversions and higher temperatures reached during the process, which is of utmost importance since the combustion catalytic methane is used for generating thermal energy. After the reaction with methane, the samples underwent significant change in surface area, probably due to the intensity of combustion reactions of the nitrate and the generation of heat involved in this reaction, which gave rise to coarse particles. During the combustion process using the obtained from particles of cerium acetylacetonate, there was the release of large quantities of nitrogen compared to the results of assays with the particles obtained with cerium nitrate. (author)

  6. Effects of fuel properties and oxidation catalyst on diesel exhaust emissions; Keiyu seijo oyobi sanka shokubai no diesel haishutsu gas eno eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Aihara, S.; Morihisa, H.; Tamanouchi, M.; Araki, H.; Yamada, S. [Petroleum Energy Center, Advanced Technology and Research Institute, Tokyo (Japan)

    1997-10-01

    Effects of fuel properties (T90 and Poly-Aromatic Hydrocarbons: PAH) and oxidation catalyst on diesel exhaust emissions were studied using three DI diesel engines and two diesel passenger cars. (IDI engine) PM emissions were found to increase as T90 and PAH increased and could be decreased considerably for each fuel if an oxidation catalyst was installed. 5 refs., 9 figs., 3 tabs.

  7. Influence of agglomeration of cerium oxide nanoparticles and speciation of cerium(III) on short term effects to the green algae Chlamydomonas reinhardtii.

    Science.gov (United States)

    Röhder, Lena A; Brandt, Tanja; Sigg, Laura; Behra, Renata

    2014-07-01

    Cerium oxide nanoparticles (CeO2 NP) are increasingly used in industrial applications and may be released to the aquatic environment. The fate of CeO2 NP and effects on algae are largely unknown. In this study, the short term effects of CeO2 NP in two different agglomeration states on the green algae Chlamydomonas reinhardtii were examined. The role of dissolved cerium(III) on toxicity, its speciation and the dissolution of CeO2 NP were considered. The role of cell wall of C. reinhardtii as a barrier and its influence on the sensitivity to CeO2 NP and cerium(III) was evaluated by testing both, the wild type and the cell wall free mutant of C. reinhardtii. Characterization showed that CeO2 NP had a surface charge of ∼0mV at physiological pH and agglomerated in exposure media. Phosphate stabilized CeO2 NP at pH 7.5 over 24h. This effect was exploited to test CeO2 NP dispersed in phosphate with a mean size of 140nm and agglomerated in absence of phosphate with a mean size of 2000nm. The level of dissolved cerium(III) in CeO2 NP suspensions was very low and between 0.1 and 27nM in all tested media. Exposure of C. reinhardtii to Ce(NO3)3 decreased the photosynthetic yield in a concentration dependent manner with EC50 of 7.5±0.84μM for wild type and EC50 of 6.3±0.53μM for the cell wall free mutant. The intracellular level of reactive oxygen species (ROS) increased upon exposure to Ce(NO3)3 with effective concentrations similar to those inhibiting photosynthesis. The agglomerated CeO2 NP caused a slight decrease of photosynthetic yield at the highest concentrations (100μM), while no effect was observed for dispersed CeO2 NP. The low toxicity of agglomerated CeO2 NP was attributed quantitatively to Ce(3+) ions co-occurring in the nanoparticle suspension whereas for dispersed CeO2 NP, dissolved Ce(3+) was precipitated with phosphate and not bioavailable. Furthermore CeO2 NP did not affect the intracellular ROS level. The cell wall free mutant and wild type of C

  8. Lipase immobilized on nanostructured cerium oxide thin film coated on transparent conducting oxide electrode for butyrin sensing

    Energy Technology Data Exchange (ETDEWEB)

    Panky, Sreedevi; Thandavan, Kavitha [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Chemical and Biotechnology, SASTRA University, Thanjavur 613 401, Tamil Nadu (India); Sivalingam, Durgajanani [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Electrical and Electronics Engineering, SASTRA University, Thanjavur 613 401, Tamil Nadu (India); Sethuraman, Swaminathan; Krishnan, Uma Maheswari [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Chemical and Biotechnology, SASTRA University, Thanjavur 613 401, Tamil Nadu (India); Jeyaprakash, Beri Gopalakrishnan [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Electrical and Electronics Engineering, SASTRA University, Thanjavur 613 401, Tamil Nadu (India); Rayappan, John Bosco Balaguru, E-mail: rjbosco@ece.sastra.edu [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Electrical and Electronics Engineering, SASTRA University, Thanjavur 613 401, Tamil Nadu (India)

    2013-01-15

    Nanostructured cerium oxide (CeO{sub 2}) thin films were deposited on transparent conducting oxide (TCO) substrate using spray pyrolysis technique with cerium nitrate salt, Ce(NO{sub 3}){sub 3}{center_dot}6H{sub 2}O as precursor. Fluorine doped cadmium oxide (CdO:F) thin film prepared using spray pyrolysis technique acts as the TCO film and hence the bare electrode. The structural, morphological and elemental characterizations of the films were carried out using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis (EDX) respectively. The diffraction peak positions in XRD confirmed the formation of highly crystalline ceria with cubic structure and FE-SEM images showed uniform adherent films with granular morphology. The band gaps of CeO{sub 2} and TCO were found to be 3.2 eV and 2.6 eV respectively. Lipase enzyme was physisorbed on the surface of CeO{sub 2}/TCO film to form the lipase/nano-CeO{sub 2}/TCO bioelectrode. Sensing studies were carried out using cyclic voltammetry and amperometry, with lipase/nano-CeO{sub 2}/TCO as working electrode and tributyrin as substrate. The mediator-free biosensor with nanointerface exhibited excellent linearity (0.33-1.98 mM) with a lowest detection limit of 2 {mu}M with sharp response time of 5 s and a shelf life of about 6 weeks. -- Graphical abstract: Nanostructured cerium oxide thin films were deposited on transparent conducting oxide (TCO) substrate using spray pyrolysis technique. Fluorine doped cadmium oxide (CdO:F) thin film acts as the TCO film and hence the working electrode. Lipase enzyme was physisorbed on the surface of CeO{sub 2}/TCO film and hence the lipase/nano-CeO{sub 2}/TCO bioelectrode has been fabricated. Sensing studies were carried out using cyclic voltammetry and amperometry with tributyrin as substrate. The mediator-free biosensor with nanointerface exhibited excellent linearity (0.33-1.98 mM) with a lowest detection limit of 2 {mu}M with sharp

  9. Predicting contamination by the fuel additive cerium oxide engineered nanoparticles within the United Kingdom and the associated risks.

    Science.gov (United States)

    Johnson, Andrew C; Park, Barry

    2012-11-01

    As a fuel additive, cerium oxide nanoparticles may become widely dispersed throughout the environment. Commercial information from the United Kingdom (UK) on the use of cerium oxide nanoparticles was used to perform a modeling and risk assessment exercise. Discharge from exhausts took into account the likely removal by filters fitted to these vehicles. For predicting current soil exposure, scenarios were examined, ranging from dispersion occurring across the entire UK landmass to only within the urban area to only 20 m on either side of road networks. For soils, the highest predicted contamination level was 0.016 mg/kg within 20 m of a road following seven years of continuous deposition. This value would represent 0.027% of reported natural background cerium. If usage were to double for five more years, levels would not be expected to exceed 0.04 mg/kg. River water contamination considered direct aerial deposition and indirect contamination via runoff in the water and entrained soil sediment, with the highest level of 0.02 ng/L predicted. The highest predicted water concentration of 300 ng/L was associated with water draining from a road surface, assuming a restricted deposition spread. These predictions are well below most toxicological levels of concern. Copyright © 2012 SETAC.

  10. A phosphate-dependent shift in redox state of cerium oxide nanoparticles and its effects on catalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Sanjay; Dosani, Talib; Karakoti, Ajay S.; Kumar, Amit; Seal, Sudipta; Self, William

    2011-10-01

    Cerium oxide nanoparticles (CeNPs) have shown promise as catalytic antioxidants in cell culture and animal models as both superoxide dismutase and catalase mimetics. The reactivity of the cerium (Ce) atoms at the surface of its oxide particle is critical to such therapeutic properties, yet little is known about the potential for a protein or small molecule corona to form on these materials in vivo. Moreover Ce atoms in these active sites have the potential to interact with small molecule anions, peptides, or sugars when administered in culture or animal models. Several nanomaterials have been shown to alter or aggregate under these conditions, rendering them less useful for biomedical applications. In this work we have studied the change in catalytic properties of CeNPs when exposed to various biologically relevant conditions in vitro. We have found that CeNPs are resistant to broad changes in pH and also not altered by incubation in cell culture medium. However to our surprise phosphate anions significantly altered the characteristics of these nanomaterials and shifted the catalytic behavior due to the binding of phosphate anions to cerium. Given the abundance of phosphate in biological systems in an inorganic form, it is likely that the action of CeNPs as a catalyst may be strongly influenced by the local concentration of phosphate in the cells and/or tissues in which it has been introduced.

  11. Ignition delay and soot oxidative reactivity of MTBE blended diesel fuel

    KAUST Repository

    Yang, Seung Yeon

    2014-04-01

    Methyl tert-butyl ether (MTBE) was added to diesel fuel to investigate the effect on ignition delay and soot oxidative reactivity. An ignition quality tester (IQT) was used to study the ignition propensity of MTBE blended diesel fuels in a reactive spray environment. The IQT data showed that ignition delay increases linearly as the MTBE fraction increases in the fuel. A four-stroke single cylinder diesel engine was used to generate soot samples for a soot oxidation study. Soot samples were pre-treated using a tube furnace in a nitrogen environment to remove any soluble organic fractions and moisture content. Non-isothermal oxidation of soot samples was conducted using a thermogravimetric analyzer (TGA). It was observed that oxidation of \\'MTBE soot\\' started began at a lower temperature and had higher reaction rate than \\'diesel soot\\' across a range of temperatures. Several kinetic analyses including an isoconversional method and a combined model fitting method were carried out to evaluate kinetic parameters. The results showed that Diesel and MTBE soot samples had similar activation energy but the pre-exponential factor of MTBE soot was much higher than that of the Diesel soot. This may explain why MTBE soot was more reactive than Diesel soot. It is suggested that adding MTBE to diesel fuel is better for DPF regeneration since an MTBE blend can significantly influence the ignition characteristics and, consequently, the oxidative reactivity of soot. Copyright © 2014 SAE International.

  12. Cellular uptake and activity of heparin functionalised cerium oxide nanoparticles in monocytes.

    Science.gov (United States)

    Ting, S R Simon; Whitelock, John M; Tomic, Romana; Gunawan, Cindy; Teoh, Wey Yang; Amal, Rose; Lord, Megan S

    2013-06-01

    Cerium oxide nanoparticles (nanoceria) are effective in scavenging intracellular reactive oxygen species (ROS). In this study nanoceria synthesized by flame spray pyrolysis (dXRD = 12 nm) were functionalised with heparin via an organosilane linker, 3-aminopropyltriethoxysilane. Nanoceria were functionalised with approximately 130 heparin molecules per nanoparticle as determined by thermo gravimetric analysis. Heparin functionalised nanoceria were more effectively internalised by the human monocyte cell line, U937, and U937 cells that had been activated with phorbol 12 myristate 13-acetate (PMA) than bare nanoceria. The heparin functionalised nanoceria were also more effective in scavenging ROS than nanoceria in both activated and unactivated U937 cells. Heparin coupled nanoceria were found to be biologically active due to their ability to bind fibroblast growth factor 2 and signal through FGF receptor 1. Additionally, the heparin-coupled nanoceria, once internalised by the cells, were found to be degraded by 48 h. Together these data demonstrated that heparin enhanced the biological properties of nanoceria in terms of cellular uptake and ROS scavenging, while the nanoceria themselves were more effective at delivering heparin intracellularly than exposing cells to heparin in solution.

  13. Impact of cerium oxide nanoparticles shape on their in vitro cellular toxicity.

    Science.gov (United States)

    Forest, Valérie; Leclerc, Lara; Hochepied, Jean-François; Trouvé, Adeline; Sarry, Gwendoline; Pourchez, Jérémie

    2017-02-01

    Cerium oxides (CeO2) nanoparticles, also referred to as nanoceria, are extensively used with a wide range of applications. However, their impact on human health and on the environment is not fully elucidated. The aim of this study was to investigate the influence of the CeO2 nanoparticles morphology on their in vitro toxicity. CeO2 nanoparticles of similar chemical composition and crystallinity were synthesized, only the shape varied (rods or octahedrons/cubes). Macrophages from the RAW264.7 cell line were exposed to these different samples and the toxicity was evaluated in terms of lactate dehydrogenase (LDH) release, Tumor Necrosis Factor alpha (TNF-α) production and reactive oxygen species (ROS) generation. Results showed no ROS production, whatever the nanoparticle shape. The LDH release and the TNF-α production were significantly and dose-dependently enhanced by rod-like nanoparticles, whereas they did not vary with cubic/octahedral nanoparticles. In conclusion, a strong impact of CeO2 nanoparticle morphology on their in vitro toxicity was clearly demonstrated, underscoring that nanoceria shape should be carefully taken in consideration, especially in a "safer by design" context.

  14. Spectrophotometric determination of H 2-receptor antagonists via their oxidation with cerium(IV)

    Science.gov (United States)

    Darwish, Ibrahim A.; Hussein, Samiha A.; Mahmoud, Ashraf M.; Hassan, Ahmed I.

    2008-01-01

    A simple, accurate and sensitive spectrophotometric method has been developed and validated for determination of H 2-receptor antagonists: cimetidine, famotidine, nizatidine and ranitidine hydrochloride. The method was based on the oxidation of these drugs with cerium(IV) in presence of perchloric acid and subsequent measurement of the excess Ce(IV) by its reaction with p-dimethylaminobenzaldehyde to give a red colored product ( λmax at 464 nm). The decrease in the absorption intensity of the colored product (Δ A), due to the presence of the drug was correlated with its concentration in the sample solution. Different variables affecting the reaction were carefully studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients (0.9990-0.9994) were found between Δ A values and the concentrations of the drugs in a concentration range of 1-20 μg ml -1. The assay limits of detection and quantitation were 0.18-0.60 and 0.54-1.53 μg ml -1, respectively. The method was validated, in terms of accuracy, precision, ruggedness and robustness; the results were satisfactory. The proposed method was successfully applied to the determination of the investigated drugs in pure and pharmaceutical dosage forms (recovery was 98.3-102.6 ± 0.57-1.90%) without interference from the common excipients. The results obtained by the proposed method were comparable with those obtained by the official methods.

  15. Role of phosphate on stability and catalase mimetic activity of cerium oxide nanoparticles.

    Science.gov (United States)

    Singh, Ragini; Singh, Sanjay

    2015-08-01

    Cerium oxide nanoparticles (CeNPs) have been recently shown to scavenge reactive oxygen and nitrogen species (ROS and RNS) in different experimental model systems. CeNPs (3+) and CeNPs (4+) have been shown to exhibit superoxide dismutase (SOD) and catalase mimetic activity, respectively. Due to their nanoscale dimension, CeNPs are expected to interact with the components of biologically relevant buffers and medium, which could alter their catalytic properties. We have demonstrated earlier that CeNPs (3+) interact with phosphate and lose the SOD activity. However, very little is known about the interaction of CeNPs (4+) with the phosphate and other anions, predominantly present in biological buffers and their effects on the catalase mimetic-activity of these nanoparticles. In this study, we report that catalase mimetic-activity of CeNPs (4+) is resistant to the phosphate anions, pH changes and composition of cell culture media. Given the abundance of phosphate anions in the biological system, it is likely that internalized CeNPs would be influenced by cytoplasmic and nucleoplasmic concentration of phosphate.

  16. Cerium oxide nanoparticle aggregates affect stress response and function in Caenorhabditis elegans.

    Science.gov (United States)

    Rogers, Steven; Rice, Kevin M; Manne, Nandini Dpk; Shokuhfar, Tolou; He, Kun; Selvaraj, Vellaisamy; Blough, Eric R

    2015-01-01

    The continual increase in production and disposal of nanomaterials raises concerns regarding the safety of nanoparticles on the environmental and human health. Recent studies suggest that cerium oxide (CeO2) nanoparticles may possess both harmful and beneficial effects on biological processes. The primary objective of this study is to evaluate how exposure to different concentrations (0.17-17.21 µg/mL) of aggregated CeO2 nanoparticles affects indices of whole animal stress and survivability in Caenorhabditis elegans. Caenorhabditis elegans were exposed to different concentrations of CeO2 nanoparticles and evaluated. Our findings demonstrate that chronic exposure of CeO2 nanoparticle aggregates is associated with increased levels of reactive oxygen species and heat shock stress response (HSP-4) in Caenorhabditis elegans, but not mortality. Conversely, CeO2 aggregates promoted strain-dependent decreases in animal fertility, a decline in stress resistance as measured by thermotolerance, and shortened worm length. The data obtained from this study reveal the sublethal toxic effects of CeO2 nanoparticle aggregates in Caenorhabditis elegans and contribute to our understanding of how exposure to CeO2 may affect the environment.

  17. Spectrophotometric determination of H(2)-receptor antagonists via their oxidation with cerium(IV).

    Science.gov (United States)

    Darwish, Ibrahim A; Hussein, Samiha A; Mahmoud, Ashraf M; Hassan, Ahmed I

    2008-01-01

    A simple, accurate and sensitive spectrophotometric method has been developed and validated for determination of H(2)-receptor antagonists: cimetidine, famotidine, nizatidine and ranitidine hydrochloride. The method was based on the oxidation of these drugs with cerium(IV) in presence of perchloric acid and subsequent measurement of the excess Ce(IV) by its reaction with p-dimethylaminobenzaldehyde to give a red colored product (lambda(max) at 464nm). The decrease in the absorption intensity of the colored product (DeltaA), due to the presence of the drug was correlated with its concentration in the sample solution. Different variables affecting the reaction were carefully studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients (0.9990-0.9994) were found between DeltaA values and the concentrations of the drugs in a concentration range of 1-20microgml(-1). The assay limits of detection and quantitation were 0.18-0.60 and 0.54-1.53microgml(-1), respectively. The method was validated, in terms of accuracy, precision, ruggedness and robustness; the results were satisfactory. The proposed method was successfully applied to the determination of the investigated drugs in pure and pharmaceutical dosage forms (recovery was 98.3-102.6+/-0.57-1.90%) without interference from the common excipients. The results obtained by the proposed method were comparable with those obtained by the official methods.

  18. Preparation and evaluation of cerium oxide-bovine hydroxyapatite composites for biomedical engineering applications.

    Science.gov (United States)

    Gunduz, O; Gode, C; Ahmad, Z; Gökçe, H; Yetmez, M; Kalkandelen, C; Sahin, Y M; Oktar, F N

    2014-07-01

    The fabrication and characterization of bovine hydroxyapatite (BHA) and cerium oxide (CeO2) composites are presented. CeO2 (at varying concentrations 1, 5 and 10wt%) were added to calcinated BHA powder. The resulting mixtures were shaped into green cylindrical samples by powder pressing (350MPa) followed by sintering in air (1000-1300°C for 4h). Density, Vickers microhardness (HV), compression strength, scanning electron microscopy (SEM) and X-ray diffraction (XRD) studies were performed on the products. The sintering behavior, microstructural characteristics and mechanical properties were evaluated. Differences in the sintering temperature (for 1wt% CeO2 composites) between 1200 and 1300°C, show a 3.3% increase in the microhardness (564 and 582.75HV, respectively). Composites prepared at 1300°C demonstrate the greatest compression strength with comparable results for 5 and 10wt% CeO2 content (106 and 107MPa) which are significantly better than those for 1wt% and those that do not include any CeO2 (90 and below 60MPa, respectively). The results obtained suggest optimal parameters to be used in preparation of BHA and CeO2 composites, while also highlighting the potential of such materials in several biomedical engineering applications.

  19. CO responses of sensors based on cerium oxide thick films prepared from clustered spherical nanoparticles.

    Science.gov (United States)

    Izu, Noriya; Matsubara, Ichiro; Itoh, Toshio; Akamatsu, Takafumi; Shin, Woosuck

    2013-03-08

    Various types of CO sensors based on cerium oxide (ceria) have been reported recently. It has also been reported that the response speed of CO sensors fabricated from porous ceria thick films comprising nanoparticles is extremely high. However, the response value of such sensors is not suitably high. In this study, we investigated methods of improving the response values of CO sensors based on ceria and prepared gas sensors from core-shell ceria polymer hybrid nanoparticles. These hybrid nanoparticles have been reported to have a unique structure: The core consists of a cluster of ceria crystallites several nanometers in size. We compared the characteristics of the sensors based on thick films prepared from core-shell nanoparticles with those of sensors based on thick films prepared from conventionally used precipitated nanoparticles. The sensors prepared from the core-shell nanoparticles exhibited a resistance that was ten times greater than that of the sensors prepared from the precipitated nanoparticles. The response values of the gas sensors based on the core-shell nanoparticles also was higher than that of the sensors based on the precipitated nanoparticles. Finally, improvements in sensor response were also noticed after the addition of Au nanoparticles to the thick films used to fabricate the two types of sensors.

  20. Effect of Cerium on Microstructures and High Temperature Oxidation Resistance of An Nb-Si System In-Situ Composite

    Institute of Scientific and Technical Information of China (English)

    Liu Aiqin; Sun Lu; Li Shusuo; Han Yafang

    2007-01-01

    Nb-16Si-24Ti-6Cr-6Al-2Hf-xCe (x=0, 0.05, 0.1, 0.25, 0.5, 1 (%, atom fraction)) in situ composites were prepared by arc melting. The microstructure and the effect of rare earth element cerium on 1250 ℃ oxidation resistance of the composites were investigated with scanning electron microscopy (SEM) and X-ray energy disperse spectrum (EDS), as well as X-ray diffraction (XRD). The experimental results showed that the high temperature oxidation resistance of the alloy was improved by adding a proper amount of cerium (Ce). The effect of Ce was considered as the concurrent of the following three factors: first, the oxide of Ce formed in the interface reduced the internal oxidation rate; second, the lath shaped oxide containing Ce increased the cracking resistance and reduced the expansion of the oxide scale; and third, the decrease of the silicide volume fraction on account of Ce addition reduces the power of the sample resisting oxy gen penetration.

  1. Nitric oxide in a diesel engine : laser-based detection and interpretation

    NARCIS (Netherlands)

    Stoffels, G.G.M.

    1999-01-01

    Nitric oxide (NO) is one of the most polluting components in the exhaust gases of a diesel engines. Therefore, knowledge of the time and place where it is produced during the combustion process is of interest to find a way to reduce diesel engine emissions. Non-intrusive optical diagnostics, based

  2. Influence of the surface pre-treatment of aluminum on the processes of formation of cerium oxides protective films

    Science.gov (United States)

    Andreeva, R.; Stoyanova, E.; Tsanev, A.; Stoychev, D.

    2016-03-01

    It is known that there is special interest in the contemporary investigations on conversion treatment of aluminum aimed at promoting its corrosion stability, which is focused on electrolytes on the basis of salts of metals belonging to the group of rare-earth elements. Their application is especially attractive, as it enables a successful substitution of the presently applied highly efficient, but at the same time toxic Cr6+-containing electrolytes. The present paper presents a study on the influence of the preliminary alkaline activation and acidic de-oxidation of the aluminum surface on the processes of immersion formation of protective cerium oxides films on Al 1050. The results obtained show that their deposition from simple electrolytes (containing only salts of Ce3+ ions) on the Al surface, treated only in alkaline solution, occurs at a higher rate, which leads to preparing thicker oxide films having a better protective ability. In the cases when the formation of oxide films is realized in a complex electrolyte (containing salts of Ce3+ and Cu2+ ions), better results are obtained with respect to the morphology and protective action of cerium oxides film on samples that have been consecutively activated in alkaline solution and deoxidized in acidic solution. Electrochemical investigations were carried out in a model corrosion medium (0.1 M NaCl); it was shown that the cerium protective films, deposited by immersion, have a cathodic character with regard to the aluminum support and inhibit the occurrence of the depolarizing corrosion process -- the reaction of oxygen reduction.

  3. Cerium oxide nanozyme modulate the ‘exercise’ redox biology of skeletal muscle

    Science.gov (United States)

    Arya, Aditya; Sethy, Niroj Kumar; Gangwar, Anamika; Bhargava, Neelima; Dubey, Amarish; Roy, Manas; Srivastava, Gaurav; Singh, Sushil Kumar; Das, Mainak; Bhargava, Kalpana

    2017-05-01

    ‘Exercise’ is a double-edged sword for the skeletal muscle. Small amount of ROS generated during mild exercise, is essential for normal force generation; whereas large quantity of ROS generated during intense exercise, may cause contractile dysfunction, resulting in muscle weakness and fatigue. One of the key question in skeletal muscle physiology is ‘could antioxidant therapy improve the skeletal muscle endurance? A question, which has resulted in contradictory experimental findings till this date. This work has addressed this ‘very question’ using a synthetic, inorganic, antioxidant nano-material viz., ‘cerium oxide nanozyme’ (CON). It has been introduced in the rat by intramuscular injection, and the skeletal muscle endurance has been evaluated. Intramuscular injections of CON, concurrent with exercise, enhanced muscle mass, glycogen and ATP content, type I fiber ratio, thus resulting in significantly higher muscle endurance. Electron microscope studies confirmed the presence of CON in the vicinity of muscle mitochondria. There was an increase in the number and size of the muscle mitochondria in the CON treated muscle, following exercise, as compared to the untreated group with only exercised muscle. Quantitative proteomics data and subsequent biological network analysis studies, identified higher levels of oxidative phosphorylation, TCA cycle output and glycolysis in CON supplemented exercised muscle over only exercised muscle. This was further associated with significant increase in the mitochondrial respiratory capacity and muscle contraction, primarily due to higher levels of electron transport chain proteins like NDUFA9, SDHA, ATP5B and ATP5D, which were validated by real-time PCR and western blotting. Along with this, persistence of CON in muscle was evaluated with ICP-MS analysis, which revealed clearance of the particles after 90 d, without exhibiting any inflammation or adverse affects on the health of the experimental animals. Thus a

  4. Deactivation of diesel oxidation catalysts. Vehicle- and synthetic aging correlations

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Jonas; Skoglundh, Magnus [Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Antonsson, Matilda [Volvo Car Corporation, Exhaust Gas Aftertreatment Diesel, SE-405 31 Goeteborg (Sweden); Eurenius, Lisa; Olsson, Eva [Microscopy and Microanalysis, Department of Applied Physics, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden)

    2007-03-08

    Deactivation characteristics of a diesel oxidation catalyst subjected to controlled lab aging were compared to field-aged catalysts after 0, 80,000, and 160,000 km driving in order to establish the (dis)similarities between the two types of aging, and determine to what extent vehicle aging can be replaced by rapid synthetic aging. Emission tests confirmed the increasing deactivation of the field-aged catalysts and measurements of CO oxidation, Pt dispersion and hydrocarbon storage capacity were used together with XPS, TEM, and SEM-EDS to compare the performance with lab-aged catalysts. The synthetic aging was designed to account for a combination of thermal and chemical deactivation. A similar degree of Pt sintering was observed for both real and synthetic aging conditions, whereas differences arose from various contributions to the chemical deactivation. XPS showed that pre-oxidation and pre-reduction at 700 C was not sufficient to remove typical compounds of oil-derived catalyst poisons (P, Zn, Ca), which furthermore accumulated with mileage, on the vehicle-aged catalysts. The degree of sulfur poisoning of the lab-aged catalysts increased with the duration of low-temperature sulfur exposure and could not be recovered in atmospheres typical for normal driving conditions. The results show that synthetic aging can be used to simulate thermal aging and a general effect of irreversible chemical deactivation, and thereby accelerate durability test procedures of various catalysts where loss of catalytic activity by time of operation is of concern. (author)

  5. Pulmonary toxicity of well-dispersed cerium oxide nanoparticles following intratracheal instillation and inhalation

    Energy Technology Data Exchange (ETDEWEB)

    Morimoto, Yasuo, E-mail: yasuom@med.uoeh-u.ac.jp; Izumi, Hiroto; Yoshiura, Yukiko; Tomonaga, Taisuke; Oyabu, Takako; Myojo, Toshihiko; Kawai, Kazuaki; Yatera, Kazuhiro [University of Occupational and Environmental Health (Japan); Shimada, Manabu; Kubo, Masaru [Hiroshima University (Japan); Yamamoto, Kazuhiro [National Institute of Advanced Industrial Science and Technology (AIST) (Japan); Kitajima, Shinichi [National Sanatorium Hoshizuka Keiaien (Japan); Kuroda, Etsushi [Osaka University, Laboratory of Vaccine Science, WPI Immunology Frontier Research Center (Japan); Kawaguchi, Kenji; Sasaki, Takeshi [National Institute of Advanced Industrial Science and Technology (AIST) (Japan)

    2015-11-15

    We performed inhalation and intratracheal instillation studies of cerium dioxide (CeO{sub 2}) nanoparticles in order to investigate their pulmonary toxicity, and observed pulmonary inflammation not only in the acute and but also in the chronic phases. In the intratracheal instillation study, F344 rats were exposed to 0.2 mg or 1 mg of CeO{sub 2} nanoparticles. Cell analysis and chemokines in bronchoalveolar lavage fluid (BALF) were analyzed from 3 days to 6 months following the instillation. In the inhalation study, rats were exposed to the maximum concentration of inhaled CeO{sub 2} nanoparticles (2, 10 mg/m{sup 3}, respectively) for 4 weeks (6 h/day, 5 days/week). The same endpoints as in the intratracheal instillation study were examined from 3 days to 3 months after the end of the exposure. The intratracheal instillation of CeO{sub 2} nanoparticles caused a persistent increase in the total and neutrophil number in BALF and in the concentration of cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-2, chemokine for neutrophil, and heme oxygenase-1 (HO-1), an oxidative stress marker, in BALF during the observation time. The inhalation of CeO{sub 2} nanoparticles also induced a persistent influx of neutrophils and expression of CINC-1, CINC-2, and HO-1 in BALF. Pathological features revealed that inflammatory cells, including macrophages and neutrophils, invaded the alveolar space in both studies. Taken together, the CeO{sub 2} nanoparticles induced not only acute but also chronic inflammation in the lung, suggesting that CeO{sub 2} nanoparticles have a pulmonary toxicity that can lead to irreversible lesions.

  6. In situ TEM studies of oxygen vacancy migration for electrically induced resistance change effect in cerium oxides.

    Science.gov (United States)

    Gao, Peng; Wang, Zhenzhong; Fu, Wangyang; Liao, Zhaoliang; Liu, Kaihui; Wang, Wenlong; Bai, Xuedong; Wang, Enge

    2010-06-01

    Oxide materials with resistance hysteresis are very promising for next generation memory devices. However, the microscopic dynamic process of the resistance change is still elusive. Here, we use in situ transmission electron microscopy method to study the role of oxygen vacancies for the resistance switching effect in cerium oxides. The structure change during oxygen vacancy migration in CeO(2) induced by electric field was in situ imaged inside high-resolution transmission electron microscope, which gives a direct evidence for oxygen migration mechanism for the microscopic origin of resistance change effect in CeO(2). Our results have implications for understanding the nature of resistance change in metal oxides with mixed valence cations, such as fluorite, rutile and perovskite oxides. Copyright 2009 Elsevier Ltd. All rights reserved.

  7. Uptake and Release of Cerium During Fe-Oxide Formation and Transformation in Fe(II) Solutions

    DEFF Research Database (Denmark)

    Nedel, Sorin; Dideriksen, Knud; Christiansen, Bo C.

    2010-01-01

    microscopy revealed that it formed discrete nanocrystals of CeO2(s). These results demonstrate that Fe-oxide interaction with radionuclides is likely to depend strongly on the local redox conditions. By analogy with Ce, the trivalent actinides are not expected to be sequestered by preformed GR in anoxic......Fe-oxides are ubiquitous in soils and sediments and form during Fe(0) corrosion. Depending on redox conditions and solution composition, Fe-oxides such as ferrihydrite, goethite, magnetite, and green rust (GR) may form. These phases typically have high surface area and large affinity for adsorption...... of trace components. Further, Fe(II)-Fe(III) (hydr)oxides are redox active. Cerium, a member of the lanthanide family, can be used as an analogue for the tri- and tetra-valent actinides found in radioactive waste, expected to be stored in subsurface repositories. In experiments with ferrihydrite, Ce...

  8. Synthesis of β-SiC/SiO_2 core-shell nanowires with the assistance of cerium oxide

    Institute of Scientific and Technical Information of China (English)

    于伟鹏; 郑瑛; 杨娥; 邱健斌; 兰瑞芳

    2010-01-01

    The β-SiC/SiO2 core-shell nanowires with the "stem-and-node" structure were synthesized in the presence of cerium oxide by the carbothermal reduction of the starch-SiO2 hybrids gel.The samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM) and energy-dispersed X-ray(EDX).The results showed that the nanowires consisted of a 20-35 nm diameter crystalline β-SiC core wrapped with a 2-5 n...

  9. Selective catalytic reduction of nitric oxide by methane over cerium and silver ion-exchanged ZSM-5 zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhijiang; Flytzani-Stephanopoulos, Maria [Department of Chemical Engineering, Tufts University, Medford, MA (United States)

    1997-12-31

    A new catalyst comprising cerium and silver ion-exchanged ZSM-5 zeolite is reported in this paper, for the reduction of nitric oxide by methane in the presence of excess oxygen. The bi-cation exchanged Ce-Ag-ZSM-5 catalyst was very active for this reaction, while either Ce-ZSM-5 or Ag-ZSM-5 alone showed low activity. The presence of oxygen in the feed gas mixture enhanced the activity of the catalyst and the NO conversion to N{sub 2} increased with the CH{sub 4}/NO ratio and Ag loading of the zeolite. The presence of water vapor had a small adverse effect on the catalyst activity. The coexistence of Ce and Ag ions in the zeolite is crucial for achieving high NO conversion to N{sub 2}. A small amount of cerium is adequate to promote the selective catalytic reduction of NO. The two main functions of Ce ions are (1) to provide the Ag ion sites with NO{sub 2} by catalyzing the oxidation of NO to NO{sub 2} and (2) to suppress the direct CH{sub 4} oxidation to CO{sub 2}. The Ag sites are the active centers where the reaction of NO{sub 2} with CH{sub 4} takes place

  10. System for operating solid oxide fuel cell generator on diesel fuel

    Science.gov (United States)

    Singh, Prabhu (Inventor); George, Raymond A. (Inventor)

    1997-01-01

    A system is provided for operating a solid oxide fuel cell generator on diesel fuel. The system includes a hydrodesulfurizer which reduces the sulfur content of commercial and military grade diesel fuel to an acceptable level. Hydrogen which has been previously separated from the process stream is mixed with diesel fuel at low pressure. The diesel/hydrogen mixture is then pressurized and introduced into the hydrodesulfurizer. The hydrodesulfurizer comprises a metal oxide such as ZnO which reacts with hydrogen sulfide in the presence of a metal catalyst to form a metal sulfide and water. After desulfurization, the diesel fuel is reformed and delivered to a hydrogen separator which removes most of the hydrogen from the reformed fuel prior to introduction into a solid oxide fuel cell generator. The separated hydrogen is then selectively delivered to the diesel/hydrogen mixer or to a hydrogen storage unit. The hydrogen storage unit preferably comprises a metal hydride which stores hydrogen in solid form at low pressure. Hydrogen may be discharged from the metal hydride to the diesel/hydrogen mixture at low pressure upon demand, particularly during start-up and shut-down of the system.

  11. Characteristics of SME biodiesel-fueled diesel particle emissions and the kinetics of oxidation.

    Science.gov (United States)

    Jung, Heejung; Kittelson, David B; Zachariah, Michael R

    2006-08-15

    Biodiesel is one of the most promising alternative diesel fuels. As diesel emission regulations have become more stringent, the diesel particulate filter (DPF) has become an essential part of the aftertreatment system. Knowledge of kinetics of exhaust particle oxidation for alternative diesel fuels is useful in estimating the change in regeneration behavior of a DPF with such fuels. This study examines the characteristics of diesel particulate emissions as well as kinetics of particle oxidation using a 1996 John Deere T04045TF250 off-highway engine and 100% soy methyl ester (SME) biodiesel (B100) as fuel. Compared to standard D2 fuel, this B100 reduced particle size, number, and volume in the accumulation mode where most of the particle mass is found. At 75% load, number decreased by 38%, DGN decreased from 80 to 62 nm, and volume decreased by 82%. Part of this decrease is likely associated with the fact that the particles were more easily oxidized. Arrhenius parameters for the biodiesel fuel showed a 2-3times greater frequency factor and approximately 6 times higher oxidation rate compared to regular diesel fuel in the range of 700-825 degrees C. The faster oxidation kinetics should facilitate regeneration when used with a DPF.

  12. Radioprotective cerium oxide nanoparticles: Molecular imaging investigations of conps' pharmacokinetics, efficacy, and mechanisms of action

    Science.gov (United States)

    McDonagh, Philip Reed Wills, III

    Cerium oxide nanoparticles (CONPs) are being investigated for several anti-oxidant applications in medicine. One of their most promising applications is as a radioprotective drug, an area of research in need due to the severe side effects from radiation therapy. In this work, the potential of CONPs as a radioprotective drug is examined using four criteria: favorable biodistribution/pharmacokinetics, low toxicity, ability to protect normal tissue from radiation damage, and lack of protection of tumor. The mechanisms of action of CONPs are also studied. Biodistribution was determined in radiolabeled CONPs with surface coatings including citrate, dextran T10-amine (DT10-NH2), dextran T10-polyethylene glycol (DT10-PEG), dextran T10-sulfobetaine (DT10-SB) and poly(acrylic acid) (PAA), and compared to uncoated. 89Zr was incorporated into CONPs for positron emission tomography (PET) imaging and ex vivo tissue analysis in tumor bearing mice. Compared to uncoated [ 89Zr]CONPs, coated [89Zr]CONPs showed improved biodistribution, including significantly enhanced renal clearance of PAA- [89Zr]CONPs. The toxicity of CONPs was evaluated in vitro and in vivo, with low toxicity at therapeutic doses. After clinically mimetic radiation therapy, pre-treatment of mice with coated and uncoated CONPs showed greater than 50% reduction of cell death in normal colon tissue, comparable to the clinically available radioprotective drug amifostine. Tumor control after irradiation of spontaneous colon tumors was unchanged with PAA-CONP pre-treatment, while citrate, DT10-PEG, and uncoated CONP pre-treatment had slightly less tumor control. Xenograft tumors were irradiated after pH normalizing treatment with sodium bicarbonate and PAA-CONP pre-treatment. Treatment of these tumors showed slightly less tumor control than irradiation alone or PAA-CONP plus irradiation, demonstrating that the acidic pH of the tumor microenvironment may be the basis of preventing CONPs' radioprotective properties in

  13. Manganese-cerium oxide catalysts prepared by non-thermal plasma for NO oxidation: Effect of O2 in discharge atmosphere

    Science.gov (United States)

    Liu, Lu; Zheng, Chenghang; Wu, Shenghao; Gao, Xiang; Ni, Mingjiang; Cen, Kefa

    2017-09-01

    Non-thermal plasma with different O2 concentration in discharge atmosphere was applied to synthesize manganese and cerium mixed-oxides catalysts, which were compared in NO oxidation activity. Discharge atmosphere displayed a crucial influence on the performance of the catalysts prepared by plasma. Relatively low O2 concentration in discharge atmosphere allows synthesizing manganese-cerium oxides catalysts in a moderate environment and therefore is favorable for better physicochemical properties which lead to superior catalytic behavior. The best catalyst was obtained by treatment with 10% O2/N2 plasma and presented over 80% NO conversion in the temperature range of 275-325 °C, whereas catalyst prepared in pure O2 discharge atmosphere had the same activity with a catalyst prepared by calcinations. A correlation between the surface properties of the plasma prepared catalysts and its catalytic activity in NO oxidation is proposed. The amount of the surface adsorbed oxygen has an obvious linear correlation with the amount of Ce3+, the H2 consumption at low temperatures and the catalytic performance. The superior catalytic performance is mainly attributed to the stronger interaction between manganese oxides and ceria, and the formation of poorly crystallized Mn-O-Ce phase in the catalyst which resulted from the slow decomposition of nitrates and organics during plasma treatment. Catalysts prepared in relatively low O2 concentration have large specific surface area and is abundant in Ce3+ species and active oxygen species. The study suggests that plasma treatment with proper discharge gas components is a promising method to prepare effective manganese- cerium oxides catalyst for NO oxidation.

  14. Cerium (IV) oxide nanotubes prepared by low temperature deposition at normal pressure

    Energy Technology Data Exchange (ETDEWEB)

    Boehme, M; Fu, G; Ionescu, E; Ensinger, W, E-mail: mboehme@ca.tu-darmstadt.de [Department of Materials Science, Darmstadt University of Technology, D-64287 Darmstadt (Germany)

    2011-02-11

    This paper reports the synthesis of cerium dioxide nanotubes (CeNTs) by electroless deposition using ion-track-etched polycarbonate templates. To achieve nanotubes with thin walls and small surface roughness the tubes were generated by a several-step-containing procedure under aqueous conditions. The approach reported below will process open end nanotubes with well-defined outer diameter and wall thickness.

  15. Cerium (IV) oxide nanotubes prepared by low temperature deposition at normal pressure.

    Science.gov (United States)

    Boehme, M; Fu, G; Ionescu, E; Ensinger, W

    2011-02-11

    This paper reports the synthesis of cerium dioxide nanotubes (CeNTs) by electroless deposition using ion-track-etched polycarbonate templates. To achieve nanotubes with thin walls and small surface roughness the tubes were generated by a several-step-containing procedure under aqueous conditions. The approach reported below will process open end nanotubes with well-defined outer diameter and wall thickness.

  16. Sulfonated macro-RAFT agents for the surfactant-free synthesis of cerium oxide-based hybrid latexes.

    Science.gov (United States)

    Garnier, Jérôme; Warnant, Jérôme; Lacroix-Desmazes, Patrick; Dufils, Pierre-Emmanuel; Vinas, Jérôme; van Herk, Alex

    2013-10-01

    Three types of amphiphatic macro-RAFT agents were employed as compatibilizers to promote the polymerization reaction at the surface of nanoceria for the synthesis of CeO2-based hybrid latexes. Macro-RAFT copolymers and terpolymers were first synthesized employing various combinations of butyl acrylate as a hydrophobic monomer and acrylic acid (AA) and/or 2-acrylamido-2-methylpropane sulfonic acid (AMPS) as hydrophilic monomers. After characterizing the adsorption of these macro-RAFT agents at the cerium oxide surface by UV-visible spectrometry, emulsion copolymerization reactions of styrene and methyl acrylate were then carried out in the presence of the surface-modified nanoceria. Dynamic Light Scattering and cryo-Transmission Electron Microscopy were employed to confirm the hybrid structure of the final CeO2/polymer latexes, and proved that the presence of acrylic acid units in amphiphatic macro-RAFT agents enabled an efficient formation of hybrid structures, while the presence of AMPS units, when combined with AA units, resulted in a better distribution of cerium oxide nanoclusters between latex particles.

  17. Nafion-porous cerium oxide nanotubes composite membrane for polymer electrolyte fuel cells operated under dry conditions

    Science.gov (United States)

    Ketpang, Kriangsak; Oh, Kwangjin; Lim, Sung-Chul; Shanmugam, Sangaraju

    2016-10-01

    A composite membrane operated in polymer electrolyte fuel cells (PEFCs) under low relative humidity (RH) is developed by incorporating cerium oxide nanotubes (CeNT) into a perfluorosulfonic acid (Nafion®) membrane. Porous CeNT is synthesized by direct heating a precursor impregnated polymer fibers at 500 °C under an air atmosphere. Compared to recast Nafion and commercial Nafion (NRE-212) membranes, the Nafion-CeNT composite membrane generates 1.1 times higher power density at 0.6 V, operated at 80 °C under 100% RH. Compared to Nafion-cerium oxide nanoparticles (Nafion-CeNP) membrane, the Nafion-CeNT provides 1.2 and 1.7 times higher PEFC performance at 0.6 V when operated at 80 °C under 100% and 18% RH, respectively. Additionally, the Nafion-CeNT composite membrane exhibits a good fuel cell operation under 18% RH at 80 °C. Specifically, the fluoride emission rate of Nafion-CeNT composite membrane is 20 times lower than that of the commercial NRE-212 membrane when operated under 18% RH at 80 °C for 96 h. The outstanding PEFC performance and durability operated under dry conditions is mainly attributed to the facile water diffusion capability as well as the effective hydroxyl radical scavenging property of the CeNT filler, resulting in significantly mitigating both the ohmic resistance and Nafion membrane degradation.

  18. Gadolinium doped cerium oxide for soot oxidation: Influence of interfacial metal–support interactions

    Energy Technology Data Exchange (ETDEWEB)

    Durgasri, D. Naga; Vinodkumar, T. [Inorganic and Physical Chemistry Division, CSIR–Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500 007 (India); Lin, Fangjian; Alxneit, Ivo [Solar Technology Laboratory, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland); Reddy, Benjaram M., E-mail: bmreddy@iict.res.in [Inorganic and Physical Chemistry Division, CSIR–Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500 007 (India)

    2014-09-30

    Graphical abstract: - Highlights: • Supported Ce-Gd-oxides are applied for soot oxidation for the first time. • Gd{sub 2}O{sub 3} doping facilitates enhanced extrinsic oxygen vacancy concentration in ceria. • The Ce-Gd/TiO{sub 2} exhibited the highest soot oxidation activity. • Key parameters that involved in tuning the activity are discussed. - Abstract: The aim of the present investigation was to ascertain the role of Al{sub 2}O{sub 3}, SiO{sub 2}, and TiO{sub 2} supports in modulating the catalytic performance of ceria-based solid solutions. In this study, we prepared nanosized Ce-Gd/Al{sub 2}O{sub 3}, Ce-Gd/SiO{sub 2}, and Ce-Gd/TiO{sub 2} catalysts by a deposition coprecipitation method and evaluated for soot oxidation. The synthesized catalysts were calcined at two different temperatures to assess their thermal stability and extensively characterized by various techniques, namely, XRD, Raman, BET surface area, TEM, H{sub 2}-TPR, and UV–vis DRS. XRD and TEM results indicate that Ce-Gd-oxide nanoparticles are in highly dispersed form on the surface of the supports. Raman results show a prominent sharp peak and a broad peak corresponding to the F{sub 2g} mode of ceria and the presence of oxygen vacancies, respectively. The presence of a significant number of oxygen vacancies in all samples is also confirmed from UV–vis DRS measurements. The H{sub 2}-TPR results suggest that Gd-doping facilitates the reduction of the materials and decreases the onset temperature of reduction. Among the prepared samples, Ce-Gd/TiO{sub 2} catalyst exhibited the highest activity, suggesting the existence of strong interfacial metal support interaction between the active metal oxide and the support.

  19. SU-E-T-279: Dose Enhancement Effect Due to Cerium Oxide Nanoparticles Employed as Radiation Protectants

    Energy Technology Data Exchange (ETDEWEB)

    Ouyang, Z; Altundal, Y; Sajo, E [Univ Massachusetts Lowell, Lowell, MA (United States); Ngwa, W [Univ Massachusetts Lowell, Lowell, MA (United States); Brigham and Women’s Hospital, Dana Farber Cancer Institute, Harvard Medical, Boston, MA (United States)

    2015-06-15

    Purpose: The goal of radiotherapy is to maximize radiation dose to diseased cells while minimizing radiation damage to normal tissues. In order to minimize damage to normal tissues, cerium oxide nanoparticles (nanoceria) are currently considered as a radioprotectant. However, some studies have reported concerns that nanoceria can also lead to radiotherapy dose enhancement due to the high atomic number of cerium, especially when used in conjunction with kV energy and brachytherapy sources. In this study, this concern is investigated to determine if the concentrations of nanoceria employed in in-vivo studies to confer radioprotection can engender a significant dose enhancement. Methods: Radiation with energies ranging from 50kVp to 140kVp is investigated in this work along with brachytherapy sources Pd-103 and I-125. A previously established theoretical model is used to calculate the dose enhancement factor (DEF). In this model, each cell is assumed to be a voxel of size (10 µm, 10 µm, 10 µm) with nanoceria homogeneously distributed among them. Electron energy loss formula of Cole is used to calculate energy (and hence dose) deposited by photoelectrons and Auger electrons in each tissue voxel due to irradiation of nanoceria. The DEF is defined as the ratio of the dose with and without nanoparticles. Results: DEF calculation results are smaller than 1.02 with dosages of nanoceria smaller than 0.645 mg/g, which is shown to be sufficiently protective by some previous in-vitro and in-vivo experiments. The brachytherapy sources show higher DEF’s than kVp radiations. DEF peaks are consistent with K shell and L shell energies of cerium, 40 keV and 6 keV, respectively. Conclusion: The results show that for sufficiently radioprotective concentrations of nanoceria, there will be minimal DEF when used in conjunction with clinically applicable kV energy radiotherapy sources or brachytherapy sources.

  20. Cerium Oxide Nanoparticles in Lung Acutely Induce Oxidative Stress, Inflammation, and DNA Damage in Various Organs of Mice

    Directory of Open Access Journals (Sweden)

    Abderrahim Nemmar

    2017-01-01

    Full Text Available CeO2 nanoparticles (CeO2 NPs which are used as a diesel fuel additive are emitted in the particulate phase in the exhaust, posing a health concern. However, limited information exists regarding the in vivo acute toxicity of CeO2 NPs on multiple organs. Presently, we investigated the acute (24 h effects of intratracheally instilled CeO2 NPs in mice (0.5 mg/kg on oxidative stress, inflammation, and DNA damage in major organs including lung, heart, liver, kidneys, spleen, and brain. Lipid peroxidation measured by malondialdehyde production was increased in the lungs only, and reactive oxygen species were increased in the lung, heart, kidney, and brain. Superoxide dismutase activity was decreased in the lung, liver, and kidney, whereas glutathione increased in lung but it decreased in the kidney. Total nitric oxide was increased in the lung and spleen but it decreased in the heart. Tumour necrosis factor-α increased in all organs studied. Interleukin- (IL- 6 increased in the lung, heart, liver, kidney, and spleen. IL-1β augmented in the lung, heart, kidney, and spleen. Moreover, CeO2 NPs induced DNA damage, assessed by COMET assay, in all organs studied. Collectively, these findings indicate that pulmonary exposure to CeO2 NPs causes oxidative stress, inflammation, and DNA damage in multiple organs.

  1. Toxicity assessment of aggregated/agglomerated cerium oxide nanoparticles in an in vitro 3D airway model: The influence of mucociliary clearance

    NARCIS (Netherlands)

    Kuper, C.F.; Gröllers-Mulderij, M.; Maarschalkerweerd, T.; Meulendijks, N.M.M.; Reus, A.; Acker, F. van; Zondervan-van den Beuken, E.K.; Wouters, M.E.L.; Bijlsma, S.; Kooter, I.M.

    2014-01-01

    We investigated the toxicity of aggregated nanoparticles of cerium oxide (CeO2) using an in vitro 3D human bronchial epithelial model that included a mucociliary apparatus (MucilAir™). CeO2 was dispersed in saline and applied to the apical surface of the model. CeO2 did not induce distinct effects

  2. Toxicity assessment of aggregated/agglomerated cerium oxide nanoparticles in an in vitro 3D airway model: The influence of mucociliary clearance

    NARCIS (Netherlands)

    Kuper, C.F.; Gröllers-Mulderij, M.; Maarschalkerweerd, T.; Meulendijks, N.M.M.; Reus, A.; Acker, F. van; Zondervan-van den Beuken, E.K.; Wouters, M.E.L.; Bijlsma, S.; Kooter, I.M.

    2014-01-01

    We investigated the toxicity of aggregated nanoparticles of cerium oxide (CeO2) using an in vitro 3D human bronchial epithelial model that included a mucociliary apparatus (MucilAir™). CeO2 was dispersed in saline and applied to the apical surface of the model. CeO2 did not induce distinct effects i

  3. Influence of rare-earth based orthovanadate nanoparticles and cerium oxide on bioenergetic processes in mitochondria of hepatocytes

    Directory of Open Access Journals (Sweden)

    Е. А. Аверченко

    2015-10-01

    Full Text Available The features of influence of newly synthesized nanoparticles (NPs based on the rare earth elements, namely orthovanadates and cerium oxide, with the different geometrical parameters on the mitochondrial potential (ΔΨm and respiration and oxidative phosphorylation of the liver were investigated. Reduction of ΔΨm, as well as the ATP level in isolated mitochondria under influence of orthovanadates and CeO2 (1-2 nm NPs suggests that energy processes in the mitochondria are the target of the action of NPs. The highest inhibitory effect was shown by ekstrasmall spherical (orthovanadate and CeO2 of 1-2 nm particles and only CeO2 with sizes of 8-10 nm have no a negative influence on all investigated parameters.

  4. Gadolinium doped cerium oxide for soot oxidation: Influence of interfacial metal-support interactions

    Science.gov (United States)

    Durgasri, D. Naga; Vinodkumar, T.; Lin, Fangjian; Alxneit, Ivo; Reddy, Benjaram M.

    2014-09-01

    The aim of the present investigation was to ascertain the role of Al2O3, SiO2, and TiO2 supports in modulating the catalytic performance of ceria-based solid solutions. In this study, we prepared nanosized Ce-Gd/Al2O3, Ce-Gd/SiO2, and Ce-Gd/TiO2 catalysts by a deposition coprecipitation method and evaluated for soot oxidation. The synthesized catalysts were calcined at two different temperatures to assess their thermal stability and extensively characterized by various techniques, namely, XRD, Raman, BET surface area, TEM, H2-TPR, and UV-vis DRS. XRD and TEM results indicate that Ce-Gd-oxide nanoparticles are in highly dispersed form on the surface of the supports. Raman results show a prominent sharp peak and a broad peak corresponding to the F2g mode of ceria and the presence of oxygen vacancies, respectively. The presence of a significant number of oxygen vacancies in all samples is also confirmed from UV-vis DRS measurements. The H2-TPR results suggest that Gd-doping facilitates the reduction of the materials and decreases the onset temperature of reduction. Among the prepared samples, Ce-Gd/TiO2 catalyst exhibited the highest activity, suggesting the existence of strong interfacial metal support interaction between the active metal oxide and the support.

  5. LSM-YSZ cathode with infiltrated cobalt oxide and cerium oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, R.; Murata, K.; Hirano, A.; Takeda, Y.; Yamamoto, O. [Department of Chemistry, Mie University, Tsu (Japan); Yamahara, K. [Mitsubihsi Chemical Corporation, Shiba, Minato-ku, Tokyo (Japan); Imanishi, N.

    2009-06-15

    To improve the La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSM) -8 mol-%Y{sub 2}O{sub 3}-ZrO{sub 2} (YSZ) cathode performance of intermediate temperature solid oxide fuel cells (SOFC), Co{sub 3}O{sub 4} and CeO{sub 2} nanoparticles were infiltrated into the cathode. Co-infiltration of these oxide particles drastically enhanced the cell performance between 800 and 600 C. The infiltrated CeO{sub 2} suppressed the aggregation of nanoparticle Co{sub 3}O{sub 4}, resulting in the high catalytic activity of the nanoparticle Co{sub 3}O{sub 4} for oxygen reduction at intermediate temperatures. The anode-supported SOFC with Co{sub 3}O{sub 4} and CeO{sub 2} co-infiltrated LSM-YSZ cathode at 700 C showed the high specific power density of 0.58 W cm{sup -2} at 0.7 V. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  6. Uptake and Release of Cerium During Fe-Oxide Formation and Transformation in Fe(II) Solutions

    DEFF Research Database (Denmark)

    Nedel, Sorin; Dideriksen, Knud; Christiansen, Bo C.

    2010-01-01

    Fe-oxides are ubiquitous in soils and sediments and form during Fe(0) corrosion. Depending on redox conditions and solution composition, Fe-oxides such as ferrihydrite, goethite, magnetite, and green rust (GR) may form. These phases typically have high surface area and large affinity for adsorption...... of trace components. Further, Fe(II)-Fe(III) (hydr)oxides are redox active. Cerium, a member of the lanthanide family, can be used as an analogue for the tri- and tetra-valent actinides found in radioactive waste, expected to be stored in subsurface repositories. In experiments with ferrihydrite, Ce......(III) release. X-ray photoelectron spectroscopy revealed Ce(III) adsorbed on magnetite. When Fe-oxides were synthesized by air oxidation of Fe(II) solutions at pH 7, GR(Na,SO4) played a catalytic role in the oxidation of Ce(III) to Ce(IV) by O-2, removing more than 90% of the dissolved Ce. Transmission electron...

  7. Chemical characteristics and oxidative potential of particulate matter emissions from gasoline, diesel, and biodiesel cars.

    Science.gov (United States)

    Cheung, Ka Lam; Polidori, Andrea; Ntziachristos, Leonidas; Tzamkiozis, Theodoros; Samaras, Zissis; Cassee, Flemming R; Gerlofs, Miriam; Sioutas, Constantinos

    2009-08-15

    Three light-duty vehicles in five different configurations [a Honda Accord operating with diesel with a closed-coupled oxidation catalyst and an underfloor catalyst replaced in some tests with a diesel particle filter (DPF), a Toyota Corolla operating with gasoline, and a VW Golf alternatively operating with petrodiesel or biodiesel] were tested in a dynamometer facility to develop an improved understanding of the factors affecting the toxicity of particulate exhaust emissions. The vehicles were tested using a variety of real-world driving cycles, more than the certification test (New European Driving Cycle). Particle samples were collected and analyzed for elemental and organic carbon (EC and OC, respectively), water soluble and water insoluble organic carbon (WSOC and WISOC, respectively), and inorganic ions, and the emission rates (mg/km) for each vehicle/configuration were determined. A dithiothreitol (DTT) assay was used to assess the oxidative potential of the particulate matter (PM) samples. The DPF-equipped diesel and gasoline vehicles were characterized by the lowest overall PM mass emissions, while the diesel and biodiesel cars produced the most potent exhaust in terms of oxidative activity. When the DPF was fitted on the Honda Accord diesel vehicle, the mass emission rates and distance-based oxidative potential were both decreased by 98%, compared to the original configuration. Correlation analysis showed that the DTT consumption rate was highly associated with WSOC, WISOC, and OC (R = 0.98, 0.93, and 0.94, respectively), consistent with previous findings.

  8. Laser induced densification of cerium gadolinium oxide: Application to single-chamber solid oxide fuel cells

    Science.gov (United States)

    Mariño, Mariana; Rieu, Mathilde; Viricelle, Jean-Paul; Garrelie, Florence

    2016-06-01

    In single-chamber solid oxide fuel cells (SC-SOFC), anode and cathode are placed in a gas chamber where they are exposed to a fuel/air mixture. Similarly to conventional dual-chamber SOFC, the anode and the cathode are separated by an electrolyte. However, as in the SC-SOFC configuration the electrolyte does not play tightness role between compartments, this one can be a porous layer. Nevertheless, it is necessary to have a diffusion barrier to prevent the transportation of hydrogen produced locally at the anode to the cathode that reduces fuel cell performances. This study aims to obtain directly a diffusion barrier through the surface densification of the electrolyte Ce0.9Gd0.1O1.95 (CGO) by a laser treatment. KrF excimer laser and Yb fiber laser irradiations were used at different fluences and number of pulses to modify the density of the electrolyte coating. Microstructural characterizations confirmed the modifications on the surface of the electrolyte for appropriate experimental conditions showing either grain growth or densified but cracked surfaces. Gas permeation and electrical conductivities of the modified electrolyte were evaluated. Finally SC-SOFC performances were improved for the cells presenting grain growth at the electrolyte surface.

  9. Laser induced densification of cerium gadolinium oxide: Application to single-chamber solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Mariño, Mariana [École Nationale Supérieure des Mines, SPIN-EMSE, CNRS: UMR 5307, LGF, F-42023 Saint-Étienne (France); Rieu, Mathilde, E-mail: rieu@emse.fr [École Nationale Supérieure des Mines, SPIN-EMSE, CNRS: UMR 5307, LGF, F-42023 Saint-Étienne (France); Viricelle, Jean-Paul [École Nationale Supérieure des Mines, SPIN-EMSE, CNRS: UMR 5307, LGF, F-42023 Saint-Étienne (France); Garrelie, Florence [Université Jean Monnet, Laboratoire Hubert Curien, CNRS: UMR 5516, 42000 Saint-Etienne (France)

    2016-06-30

    Graphical abstract: - Highlights: • CGO surface densifications were induced by UV and IR laser irradiations. • Grain growth or densified cracked surfaces were observed by SEM. • UV laser treatments allow a decrease of gas permeation through electrolyte layer. • Electrical conductivity of the electrolyte was modified by laser treatments. • Grain growth of electrolyte induced by UV laser improved cell performances. - Abstract: In single-chamber solid oxide fuel cells (SC-SOFC), anode and cathode are placed in a gas chamber where they are exposed to a fuel/air mixture. Similarly to conventional dual-chamber SOFC, the anode and the cathode are separated by an electrolyte. However, as in the SC-SOFC configuration the electrolyte does not play tightness role between compartments, this one can be a porous layer. Nevertheless, it is necessary to have a diffusion barrier to prevent the transportation of hydrogen produced locally at the anode to the cathode that reduces fuel cell performances. This study aims to obtain directly a diffusion barrier through the surface densification of the electrolyte Ce{sub 0.9}Gd{sub 0.1}O{sub 1.95} (CGO) by a laser treatment. KrF excimer laser and Yb fiber laser irradiations were used at different fluences and number of pulses to modify the density of the electrolyte coating. Microstructural characterizations confirmed the modifications on the surface of the electrolyte for appropriate experimental conditions showing either grain growth or densified but cracked surfaces. Gas permeation and electrical conductivities of the modified electrolyte were evaluated. Finally SC-SOFC performances were improved for the cells presenting grain growth at the electrolyte surface.

  10. CuO/CeO{sub 2} catalysts prepared with different cerium supports for CO oxidation at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chi-Yuan [School of Public Health, Chung Shan Medical University, Taichung 402, Taiwan, ROC (China); Department of Occupational Medicine, Chung Shan Medical University Hospital, Taichung 402, Taiwan, ROC (China); Chang, Wen-Chi [Department of Environmental Engineering, National Chung Hsing University, Taichung 402, Taiwan, ROC (China); Wey, Ming-Yen, E-mail: mywey@dragon.nchu.edu.tw [Department of Environmental Engineering, National Chung Hsing University, Taichung 402, Taiwan, ROC (China)

    2013-08-15

    The activity of a catalyst depends on the nature of its support, its active site, and its preparation method. This study aimed to employ various types of CeO{sub 2} supports such as commercial CeO{sub 2} and self-prepared CeO{sub 2} for the preparation of copper catalysts. The CuO/CeO{sub 2} catalysts were prepared using the polyol process and impregnation method. The catalysts were characterized using Brunauer–Emmett–Teller analysis, scanning electron microscopy, and X-ray analysis, and their catalytic activity for CO removal was evaluated in a microcatalytic reactor. The experimental results showed that the catalytic activity of the CuO/CeO{sub 2} catalysts with different calcination temperatures decreased in the following order: 500 °C > 300 °C > 700 °C. Compared to the impregnation method, the polyol process generated well-dispersed metal particles over the support and showed higher CO removal efficiency with low activation energy. Compared to CuO/CeO{sub 2} catalysts with commercial CeO{sub 2}, those with CeO{sub 2} that was self-prepared by pyrolysis had a large pore volume and good crystal structure of CeO{sub 2} and showed good performance. The catalytic activity for CO removal was in the following order: CuO/CeO{sub 2}-P (pyrolysis) > CuO/CeO{sub 2}-C (commercial) > CuO/CeO{sub 2}-D (deposition precipitation). CuO/CeO{sub 2}-P catalysts showed good activity even at low temperature. The CuO/CeO{sub 2}-P(300)-P-120 min catalyst was found to possess the good CO removal rate when the oxygen content was 6%, CO concentration was 500 ppm, catalyst weighed 1.0 g, pollutant gas velocity was 500 mL min{sup −1}, SV was 3.7 × 10{sup 4} h{sup −1}, and reaction temperature was 150 °C. - Highlights: • CuO/CeO{sub 2} catalysts were prepared using polyol and impregnation methods. • The supports of catalyst were self-prepared cerium oxide and commercial cerium oxide. • Pyrolysis and deposition precipitation methods were used for cerium preparation.

  11. Oxidation behaviour and electrical properties of cobalt/cerium oxide composite coatings for solid oxide fuel cell interconnects

    DEFF Research Database (Denmark)

    Harthøj, Anders; Holt, Tobias; Møller, Per

    2015-01-01

    are exposed in air at 800 °C for 3000 h and oxidation rates are measured and oxide scale microstructures are investigated. Area-specific resistances (ASR) in air at 850 °C of coated and uncoated samples are also measured. A dual layered oxide scale formed on all coated samples. The outer layer consisted of Co...

  12. Effect of exhaust gas recirculation on diesel engine nitrogen oxide reduction operating with jojoba methyl ester

    Energy Technology Data Exchange (ETDEWEB)

    Saleh, H.E. [Mechanical Power Department, Faculty of Engineering, Mattaria, Helwan University, 9 k Eltaaweniat, Nasr Road, P.O. Box 11718, Cairo (Egypt)

    2009-10-15

    Jojoba methyl ester (JME) has been used as a renewable fuel in numerous studies evaluating its potential use in diesel engines. These studies showed that this fuel is good gas oil substitute but an increase in the nitrogenous oxides emissions was observed at all operating conditions. The aim of this study mainly was to quantify the efficiency of exhaust gas recirculation (EGR) when using JME fuel in a fully instrumented, two-cylinder, naturally aspirated, four-stroke direct injection diesel engine. The tests were carried out in three sections. Firstly, the measured performance and exhaust emissions of the diesel engine operating with diesel fuel and JME at various speeds under full load are determined and compared. Secondly, tests were performed at constant speed with two loads to investigate the EGR effect on engine performance and exhaust emissions including nitrogenous oxides (NO{sub x}), carbon monoxide (CO), unburned hydrocarbons (HC) and exhaust gas temperatures. Thirdly, the effect of cooled EGR with high ratio at full load on engine performance and emissions was examined. The results showed that EGR is an effective technique for reducing NO{sub x} emissions with JME fuel especially in light-duty diesel engines. With the application of the EGR method, the CO and HC concentration in the engine-out emissions increased. For all operating conditions, a better trade-off between HC, CO and NO{sub x} emissions can be attained within a limited EGR rate of 5-15% with very little economy penalty. (author)

  13. Quantitative laser-induced fluorescence measurements of nitric oxide in a heavy-duty Diesel engine

    NARCIS (Netherlands)

    Verbiezen, K.; Klein-Douwel, R. J. H.; van Viet, A. P.; Donkerbroek, A. J.; Meerts, W. L.; Dam, N. J.; ter Meulen, J. J.

    2007-01-01

    We present quantitative, in-cylinder, UV-laser-induced fluorescence measurements of nitric oxide in a heavy-duty Diesel engine. Processing of the raw fluorescence signals includes a detailed correction, based on additional measurements, for the effect of laser beam and fluorescence attenuation, and

  14. Mechanochemical synthesis of cerium orthophosphate

    Institute of Scientific and Technical Information of China (English)

    A.Matraszek; I.Szczygiei; L.Macalik; J.Hanuza

    2009-01-01

    A facile,simple and rapid preparation method of cerium orthophosphate was presented.The synthesis of low-crystalline CePO4 occurred upon mixing of cerium (Ⅲ) nitrate and sodium phosphate,and was an exchange-type reaction.The phase composition of the obtained powder was checked by the XRD and FTIR methods,indicating the presence of cerium phosphate.Further investigations on thermal behavior of the synthesized cerium salt had shown that the obtained onhophosphate crystallized at first in rhabdophane-type structure.It convetted to monazite (monoclinic symmetry) during heating at the temperatures of above 600 ℃.Oxidation of Ce3+ to Ce4+ was avoided during the syntheses,as confirmed by the XPS experiments.

  15. Removal of Nitrogen Oxides in Diesel Engine Exhaust by Plasma Assisted Molecular Sieves

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper reports the studies conducted on removal of oxides of nitrogen (NOx) from diesel engine exhaust using electrical discharge plasma combined with adsorbing materials such as molecular sieves. This study is being reported for the first time. The exhaust is taken from a diesel engine of 6 kW under no load conditions. The characteristic behavior of a pulse energized dielectric barrier discharge reactor in the diesel exhaust treatment is reported. The NOx removal was not significant (36%) when the reactor without any packing was used. However, when the reactor was packed with molecular sieves (MS -3A, -4A & -13X), the NOx removal efficiency was increased to 78% particularly at a temperature of 200 o C. The studies were conducted at different temperatures and the results were discussed.

  16. Catalytic Effect of Cerium Oxide on Carburization of Steel%氧化铈在钢表面气相渗碳时的催化作用

    Institute of Scientific and Technical Information of China (English)

    袁泽喜; 谭平; 余宗森; 徐庭栋

    2001-01-01

    Comparing the kinetics of gas carburization of steel 20 with the carburization agent containing cerium oxide or without it,it is found that cerium oxide in carburant can accelerate carburizing process greatly,which almost has the same effect at 850℃ and 910℃.This effect is accomplished by catalyzing mechanism of cerium oxide.RE in steel can also accelerate carburizing process,but its effect is less than RE in carburant. RE in steel can improve the catalysis of RE in carburant.%在20钢气相渗碳时对比了渗剂中加入CeO2或不加CeO2时的渗碳动力学,发现在渗剂中加入CeO2可以显著加快渗碳速率。稀土催渗剂的效果在850℃和910℃基本相同。认为CeO2加速渗碳的机制是催化。冶炼时在钢中加入的稀土对渗碳也起加速作用,但作用小于渗剂中的稀土。它还可以增强渗剂中稀土的催渗作用。

  17. A nitrilo-tri-acetic-acid/acetic acid route for the deposition of epitaxial cerium oxide films as high temperature superconductor buffer layers

    Science.gov (United States)

    Thuy, T. T.; Lommens, P.; Narayanan, V.; Van de Velde, N.; De Buysser, K.; Herman, G. G.; Cloet, V.; Van Driessche, I.

    2010-09-01

    A water based cerium oxide precursor solution using nitrilo-tri-acetic-acid (NTA) and acetic acid as complexing agents is described in detail. This precursor solution is used for the deposition of epitaxial CeO 2 layers on Ni-5at%W substrates by dip-coating. The influence of the complexation behavior on the formation of transparent, homogeneous solutions and gels has been studied. It is found that ethylenediamine plays an important role in the gelification. The growth conditions for cerium oxide films were Ar-5% gas processing atmosphere, a solution concentration level of 0.25 M, a dwell time of 60 min at 900 °C and 5-30 min at 1050 °C. X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM), pole figures and spectroscopic ellipsometry were used to characterize the CeO 2 films with different thicknesses. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) was used to determine the carbon residue level in the surface of the cerium oxide film, which was found to be lower than 0.01%. Textured films with a thickness of 50 nm were obtained.

  18. Evaluation of cerium oxide coated Cu cermets as inert anodes for aluminum electrowinning. Final report, August 1990--March 1992

    Energy Technology Data Exchange (ETDEWEB)

    1992-08-01

    Cu/NiFe{sub 2}O{sub 4} cermets were evaluated, with and without an in-situ deposited CEROX (TM; cerium oxide) coating, in 100 h laboratory A1 electrowinning tests. Bath ratio and current density were varied between tests and corrosion was determined by contamination of the aluminum and cryolite by cermet components (Cu, Fe, and Ni). Higher bath ratios of 1.5 to 1.6 led to less corrosion and thicker CEROX coatings. Lower current densities led to slightly less corrosion but much less oxidation of the Cu cermet substrate. At identical test conditions, the corrosion of the CEROX coated cermets was 1/7 that of an uncoated cermet. Corrosion was increased in CEROX coated cermets tested under unsaturated alumina conditions. The electrical conductivity of the CEROX coating was measured to be {approximately}0.2 ohm{sup {minus}1}cm{sup {minus}1}, resulting in a slight voltage penalty, depending on the thickness of the coating.

  19. Cerium Oxide Nanoparticles Induced Toxicity in Human Lung Cells: Role of ROS Mediated DNA Damage and Apoptosis

    Directory of Open Access Journals (Sweden)

    Sandeep Mittal

    2014-01-01

    Full Text Available Cerium oxide nanoparticles (CeO2 NPs have promising industrial and biomedical applications. In spite of their applications, the toxicity of these NPs in biological/physiological environment is a major concern. Present study aimed to understand the molecular mechanism underlying the toxicity of CeO2 NPs on lung adenocarcinoma (A549 cells. After internalization, CeO2 NPs caused significant cytotoxicity and morphological changes in A549 cells. Further, the cell death was found to be apoptotic as shown by loss in mitochondrial membrane potential and increase in annexin-V positive cells and confirmed by immunoblot analysis of BAX, BCl-2, Cyt C, AIF, caspase-3, and caspase-9. A significant increase in oxidative DNA damage was found which was confirmed by phosphorylation of p53 gene and presence of cleaved poly ADP ribose polymerase (PARP. This damage could be attributed to increased production of reactive oxygen species (ROS with concomitant decrease in antioxidant “glutathione (GSH” level. DNA damage and cell death were attenuated by the application of ROS and apoptosis inhibitors N-acetyl-L- cysteine (NAC and Z-DEVD-fmk, respectively. Our study concludes that ROS mediated DNA damage and cell cycle arrest play a major role in CeO2 NPs induced apoptotic cell death in A549 cells. Apart from beneficial applications, these NPs also impart potential harmful effects which should be properly evaluated prior to their use.

  20. Evaluation of titanium dioxide and cerium oxide as anodes for the electrooxidation of toluene A theoretical approach of the electrode process

    Energy Technology Data Exchange (ETDEWEB)

    D' Elia, Luis F.; Rincon, L.; Ortiz, R

    2004-09-30

    Cerium oxide and titanium dioxide were prepared by thermal decomposition of the precursor salts and thermal treatment of titanium plates. In aqueous medium, the metal oxides show a well-defined electrochemical reaction; a solid state redox process takes place in the cathodic range of potentials and only water discharge reaction occurs in the anodic region. At the experimental conditions, the prepared materials were not totally active for the electrooxidation of toluene. The theoretical modeling suggests that the lack of activity is due to the weak interaction between toluene and the metal oxide surface.

  1. Integrated modeling of nitrogen oxides formation in diesel engines

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To account for the effects of both chemistry and flow turbulence,the present study proposes an integrated NO sub-model that combines the extended Zel'dovich mechanism and engine CFD computations to simulate the NO histories in a diesel engine.NOx sub-model parameters and pollutant formation mechanisms can be more easily investigated by solving the NOx sub-model.The new NO formation model incorporating the effects of hoth chemical kinetics and turbulent mixing was applied to simulate a diesel engine with a quiescent combustion chamber,and one with a re-entrant combustion chamber;the premise of the model being the reaction rate is mainlv determined by a kinetic timescale and a turbulent timescale.The results indicate that the predicted NO formulation from the new model agrees well with the measured data.As the utilization of fossil fuels continues to increase,the control of NOx emissions is a worldwide concern;and it is imperative to understand fully the NOx reaction processes in combustion systems.This technology has the Dotential to enhance the application of various combustion techniques used to reduce NOx emissions from practical combustion systems.

  2. 模板组装纳米结构氧化铈催化材料%The Study of Cerium Oxide Nanostructure Catalytic Materials by Templated Assemble

    Institute of Scientific and Technical Information of China (English)

    张久兴; 杜玉成; 孙立柏; 何洪

    2003-01-01

      介绍了模板剂结构诱导下均相沉淀法组装纳米结构氧化铈工艺方法.0.02mol SDS、0.01mol Ce(NO3)·6H2O、0.44mol (NH2)2CO,反应72h可获得肩峰较宽、具有CeO2,Ce2O3固溶峰的、粒径在5~10nm、孔径在3~5nm、比表面积达181.45m2/g的纳米结构氧化铈.N2吸附分析表明样品具有良好的吸附催化活性.%  In this paper, the nanostructure cerium-oxide-based surfactant mesophases templated by template agent assemblies were synthesized by homogeneous precipitation method. Nanostructure cerium oxide has been obtained, when SDS, cerium nitrate, urea were mixed at the molar ratio of 0.02mol, 0.01mol, 0.44mol and have been reacted 72h. The cerium oxide was characterized by a wider shoulder peak of CeO2 and Ce2O3, and the character with the mean particle size of 5~10nm, pore size 3~5nm, specific surface area of as large as 181.45m2/g. As catalyst, the sample has better absorption property by absorbed of nitrogen gas .

  3. Superiority of DFT+U with non-linear core correction for open-shell binary rare-earth metal oxides: a case study of native point defects in cerium oxides

    Science.gov (United States)

    Huang, Bolong

    2014-09-01

    We successfully proposed a newly corrected density functional theory plus Hubbard U parameter (DFT + U) based on partial core correction on the orbitals within norm-conserving lanthanide atomic pseudopotentials. A related and comprehensive investigation of native point defects in cerium oxides has also been performed as an examine by practice.

  4. A cerium(IV)-carbon multiple bond

    Energy Technology Data Exchange (ETDEWEB)

    Gregson, Matthew; Lu, Erli; McMaster, Jonathan; Lewis, William; Blake, Alexander J.; Liddle, Stephen T. [Nottingham Univ. (United Kingdom). School of Chemistry

    2013-12-02

    Straightforward access to a cerium(IV)-carbene complex was provided by one-electron oxidation of an anionic ''ate'' cerium(III)-carbene precursor, thereby avoiding decomposition reactions that plague oxidations of neutral cerium(III) compounds. The cerium(IV)-carbene complex is the first lanthanide(IV)-element multiple bond and involves a twofold bonding interaction of two electron pairs between cerium and carbon. [German] Auf direktem Wege zu einem Cer(IV)-Carbenkomplex gelangt man durch die Einelektronenoxidation einer anionischen Carben-Cerat(III)-Vorstufe. So werden Zersetzungsprozesse vermieden, die die Oxidation neutraler Cer(III)-Verbindungen erschweren. Der Cer(IV)-Carbenkomplex enthaelt die erste Lanthanoid(IV)-Element-Mehrfachbindung; dabei binden Cer und Kohlenstoff ueber zwei Elektronenpaare.

  5. Polyacrylic acid-coated cerium oxide nanoparticles: An oxidase mimic applied for colorimetric assay to organophosphorus pesticides.

    Science.gov (United States)

    Zhang, Shi-Xiang; Xue, Shi-Fan; Deng, Jingjing; Zhang, Min; Shi, Guoyue; Zhou, Tianshu

    2016-11-15

    It is important and urgent to develop reliable and highly sensitive methods that can provide on-site and rapid detection of extensively used organophosphorus pesticides (OPs) for their neurotoxicity. In this study, we developed a novel colorimetric assay for the detection of OPs based on polyacrylic acid-coated cerium oxide nanoparticles (PAA-CeO2) as an oxidase mimic and OPs as inhibitors to suppress the activity of acetylcholinesterase (AChE). Firstly, highly dispersed PAA-CeO2 was prepared in aqueous solution, which could catalyze the oxidation of TMB to produce a color reaction from colorless to blue. And the enzyme of AChE was used to catalyze the substrate of acetylthiocholine (ATCh) to produce thiocholine (TCh). As a thiol-containing compound with reducibility, TCh can decrease the oxidation of TMB catalyzed by PAA-CeO2. Upon incubated with OPs, the enzymatic activity of AChE was inhibited to produce less TCh, resulting in more TMB catalytically oxidized by PAA-CeO2 to show an increasing blue color. The two representative OPs, dichlorvos and methyl-paraoxon, were tested using our proposed assay. The novel assay showed notable color change in a concentration-dependent manner, and as low as 8.62 ppb dichlorvos and 26.73 ppb methyl-paraoxon can be readily detected. Therefore, taking advantage of such oxidase-like activity of PAA-CeO2, our proposed colorimetric assay can potentially be a screening tool for the precise and rapid evaluation of the neurotoxicity of a wealth of OPs.

  6. Desulfurization of diesel by oxidation/extraction scheme. Influence of the extraction solvent

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez-Verduzco, L.F.; Torres-Garcia, E.; Gomez-Quintana, R.; Gonzalez-Pena, V.; Murrieta-Guevara, F. [Programa de Tratamiento de Crudo Maya, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, CP 07730 Mexico, DF (Mexico)

    2004-11-24

    Due to the future specifications for sulfur content in middle distillate like diesel, a lot of research work has been done to develop alternative methods for desulfurization. This work presents the results for the desulfurization of diesel by an oxidation and extraction (O/E) scheme. This process can be considered like a post-treatment to the traditional hydrodesulfurization. A diesel with 320ppmw of total sulfur was employed to evaluate the elimination of sulfur compounds. The oxidation reaction was carried out with hydrogen peroxide at 30wt.%, in a heterogeneous system with a WO{sub x}/ZrO{sub 2} catalyst at 15wt.% of W; the extraction was performed with four polar solvents. The experiments were done in a batch reactor at 333K and atmospheric pressure. As an average, the sulfur content in the diesel after treatment was 90ppmw. A speciation of the sulfur compounds before and after O/E scheme was also included. Additionally, solubility data of dibenzothiophene sulfone in the polar solvents as a function of temperature were obtained.

  7. Experimental investigations on a CRDI system assisted diesel engine fuelled with aluminium oxide nanoparticles blended biodiesel

    Directory of Open Access Journals (Sweden)

    C. Syed Aalam

    2015-09-01

    Full Text Available Experiments were conducted to determine engine performance, exhaust emissions and combustion characteristics of a single cylinder, common rail direct injection (CRDI system assisted diesel engine using diesel with 25 percentage of zizipus jujube methyl ester blended fuel (ZJME25. Along with this ZJME25 aluminium oxide nanoparticles were added as additive in mass fractions of 25 ppm (AONP 25 and 50 ppm (AONP 50 with the help of a mechanical Homogenizer and an ultrasonicator. It was observed that aluminium oxide nanoparticles blended fuel exhibits a significant reduction in specific fuel consumption and exhaust emissions at all operating loads. At the full load, the magnitude of HC and smoke emission for the ZJME25 before the addition of aluminium oxide nanoparticles was 13.459 g/kW h and 79 HSU, whereas it was 8.599 g/kW h and 49 HSU for the AONP 50 blended ZJME25 fuel respectively. The results also showed a considerable enhancement in brake thermal efficiency and heat release rate due to the influence of aluminium oxide nanoparticles addition in biodiesel–diesel blend.

  8. Cerium oxide nanoparticles coated by surfactant sodium bis(2—ethylhexyl) sulphosuccinate(AOT):local atomic structures and x—ray absorption spectroscopic studies

    Institute of Scientific and Technical Information of China (English)

    ZhonghuaWu; RobertEBenfield; LinGuo; HuanjunLi; QinglinYang; Didier

    2001-01-01

    Cerium oxide nanoparticles coated by sodium bis(2-ethylexyl) sulphosuccinate(AOT) were prepared by using a microemulsion method.Transmission electron microscopy revealed an average particle siae of 2-3nm.X-ray diffraction showed that the cerium oxide nanoparticles retain the CeF2-type cubic structures like the bulk crystal.The intermediate valence offormally tetravalent compounds had been detected by x-ray-absorption near-edge structetravalent compounds had been detected by x-ray-absorption near-dege structure(XANES) spectra of Ce LIII absorption in bulk CeO2 and the cerium oxide nanoparticles.Two well resoved white lines can be assigned to the electron configurations of 4f0L and 4f1L,respectively,where L denotes a ligand hole.At the same time,the cerium oxide nanoparticles also showed the structural featres of trivalent compounds,in comparison to the trivalent Ce(NO3)3·6H2O.Fuor Lorentzian functions and two arctan functions were used to fit the normalized XANES spectra.The extended x-ray-absorption fine-structure(EXAFS) technique was used to probe the local atomic structures around the absorber Ce.The multielectrorn excitation effect on the EXAFS spectra was eliminated.A cor-shell model was used to deduce the near-neighbour structural parameters around cerium.Bulk CeO2 with eight oxygen atoms located at 2.343A was used as the reference sample to extract the backscattering amplitude and phase shift of the Ce-O bond.One half of the atome locate at the core part with the CeF2-type cubic structures(eight oxyens at 2.343A around Ce),the other half of the atoms are amorphous phase located in the shell part (surface of the nanoparticles) with approximately Ce2O3 structural features (averageed seven oxygens at 2.50A around Ce).

  9. Study on photocatalytic performance of cerium-graphene oxide-titanium dioxide composite film for formaldehyde removal

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jia; Zhang, Quan [The Civil Engineering College of Hunan University, Changsha (China); Lai, Alvin C.K. [Department of Civil and Architectural Engineering, City University of Hong Kong, Kowloon (China); Zeng, Liping [Department of Building Engineering of Hunan Institute of Engineering, Xiangtan (China)

    2016-12-15

    In order to degrade in-car formaldehyde gas, graphene oxide (GO), cerium (Ce), and TiO{sub 2} were organically combined by one-step sol-gel method. Then the mixed collosol was coated onto the surface of inorganic glass substrates to form Ce-GO-TiO{sub 2} composite film by way of immersion, coating, and calcinations. The morphology and crystal structure of as-prepared Ce-GO-TiO{sub 2} film were studied by a series of detection techniques. The photocatalytic performance of this film was analyzed by the degradation effect of formaldehyde under simulated sunlight. The results showed that the Ce-GO-TiO{sub 2} film had the inbuilt mesoporous structure in the lamellar stacking with particles. When the doping amount of Ce and GO were 0.4 and 0.2% (mass ratio), the composite film can improve effectively the response to the visible light and its degradation rate for low concentration of formaldehyde was up to 83.8% in simulated sunlight for 7 h, which could be attributed to the co-function of Ce and GO. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Effects of cerium oxide nanoparticles on the species and distribution of phosphorus in enhanced phosphorus removal sequencing batch biofilm reactor.

    Science.gov (United States)

    Xu, Yi; Wang, Chao; Hou, Jun; Wang, Peifang; You, Guoxiang; Miao, Lingzhan; Lv, Bowen; Yang, Yangyang

    2017-03-01

    The short term (8h) influences of cerium oxide nanoparticles (CeO2NPs) on the process of phosphorus removal in biofilm were investigated. At concentration of 0.1mg/L, CeO2 NPs posed no impacts on total phosphorus (TP) removal. While at 20mg/L, TP removal efficiency reduced from 85.16% to 59.62%. Results of P distribution analysis and (31)P nuclear magnetic resonance spectroscopy implied that the anaerobic degradation of polyphosphate (polyP) and the release of orthophosphate in extracellular polymeric substances (EPS) were inhibited. After aerobic exposure, the average chain length of polyP in microbial cells and EPS was shorter than control, and monoester and diester phosphates in cells were observed to release into EPS. Moreover, the EPS production and its contribution to P removal increased, while the capacity of EPS in P storage declined. X-ray diffraction analysis and saturation index calculation revealed that the formation of inorganic P precipitation in biofilm was inhibited.

  11. Kinetics and Mechanism of Iridium(Ⅲ)-Catalyzed Oxidation of Ethanol Amine by Cerium(Ⅳ) in Sulfuric Acid Media

    Institute of Scientific and Technical Information of China (English)

    ZHAI Yong-qing; LIU Hong-mei; YANG Lin; YANG Guo-zhong; SONG Wen-yu; LIU Yu-kai

    2007-01-01

    In this study, the kinetics and mechanism of the iridium(Ⅲ)-catalyzed oxidation of ethanol amine(EAN) by cerium(Ⅳ) in a sulfuric acid medium was investigated using titrimetric technique of redox in a temperature range of 298-313 K. It was found that the reaction is of first order with respect to Ce(Ⅳ) and Ir(Ⅲ), and a positive fractional order with respect to EAN. It was also found that the pseudo-first-order([EAN](》)[Ce(Ⅳ)]) rate constant kobs decreases with the increase of [H+] and [HSO-4]. Under the protection of nitrogen gas, the reaction system can initiate the polymerization of acrylonitrile, indicating the generation of free radicals. On the basis of the experimental results, a suitable mechanism was proposed. From the dependence of kobs on the concentration of hydrogen sulfate, Ce(SO4)2 was found to be the kinetically active species. The rate constants of the rate-determining step together with the activation parameters were evaluated.

  12. Particle-specific toxicity and bioavailability of cerium oxide (CeO2) nanoparticles to Arabidopsis thaliana.

    Science.gov (United States)

    Yang, Xinping; Pan, Haopeng; Wang, Peng; Zhao, Fang-Jie

    2017-01-15

    The use of manufactured cerium oxide nanoparticles (CeO2-NPs) in consumer products has increased markedly over the past decade, and their release into natural ecosystems is unavoidable. This study investigated the phytotoxicity and uptake of CeO2-NPs in Arabidopsis thaliana grown in an agar medium. Although low concentrations of CeO2-NPs had stimulatory effects on plant growth, at higher concentrations, CeO2-NPs reduced growth and had adverse effects on the antioxidant systems and photosystem. Importantly, the toxicity resulted from the nanoparticles per se, rather than from the dissolved Ce ions. CeO2-NPs were taken up and subsequently translocated to shoot tissues, and transmission electron microscopy (TEM) showed the presence of a large number of needle-like particle aggregations in the intercellular regions and the cytoplasm of leaf cells. The up-translocation factor to shoots was independent of the concentrations of Ce in the roots and the supplied forms of Ce (i.e. CeO2-NPs, CeO2-bulk, and ionic Ce), suggesting that endocytosis is likely to be a general mechanism responsible for the translocation of these Ce compounds. These findings provide important information regarding the toxicity and uptake of CeO2-NPs in plants, which needs to be considered in environmental risk assessment for the safe use and disposal of CeO2-NPs.

  13. Transport of cerium oxide nanoparticles in saturated silica media: influences of operational parameters and aqueous chemical conditions

    Science.gov (United States)

    Zhang, Zhaohan; Gao, Peng; Qiu, Ye; Liu, Guohong; Feng, Yujie; Wiesner, Mark

    2016-10-01

    This paper aimed to investigate the influences of operational parameters and aqueous chemical conditions on transport behaviors of cerium oxides nanoparticles (CeO2-NPs) in saturated silica media. Results indicated that increasing rates of attachment efficiency (α) were related with cationic types, and critical deposition concentration (CDC) for divalent cation (Ca2+ and Mg2+) were more than 31-fold of that for monovalent cation (Na+ and K+). Increase or reduction of electrolyte pH could both promote the mobility of CeO2-NPs in glass beads, while influence was more evident at alkaline conditions. α increased linearly with NPs concentrations, while decreased linearly with flow velocity in the column, and effects were related with electrolyte contents. Presence of surfactants could sharply decreased α, and SDS was more effective to facilitate CeO2-NPs transport than Triton X-100. With DOMs concentrations increasing, α firstly kept constant, then sharply declined, and finally reduced very slowly. The influence of DOMs on NPs deposition was in order of SA > HA > TA >  BSA. Overall, this study revealed that aqueous chemical conditions was crucial to NPs transport in porous media, and would provide significant information for our understanding on the fate and transport of nanoparticles in natural environment.

  14. Microwave synthesis of pure and doped cerium (IV) oxide (CeO2) nanoparticles for methylene blue degradation.

    Science.gov (United States)

    El Rouby, W M A; Farghali, A A; Hamdedein, A

    2016-11-01

    Cerium (IV) oxide (CeO2), samarium (Sm) and gadolinium (Gd) doped CeO2 nanoparticles were prepared using microwave technique. The effect of microwave irradiation time, microwave power and pH of the starting solution on the structure and crystallite size were investigated. The prepared nanoparticles were characterized using X-ray diffraction, FT-Raman spectroscopy, and transmission electron microscope. The photocatalytic activity of the as-prepared CeO2, Sm and Gd doped CeO2 toward degradation of methylene blue (MB) dye was investigated under UV light irradiation. The effect of pH, the amount of catalyst and the dye concentration on the degradation extent were studied. The photocatalytic activity of CeO2 was kinetically enhanced by trivalent cation (Gd and Sm) doping. The results revealed that Gd doped CeO2 nanoparticles exhibit the best catalytic degradation activity on MB under UV irradiation. For clarifying the environmental safety of the by products produced from the degradation process, the pathways of MB degradation were followed using liquid chromatography/mass spectroscopy (LC/MS). The total organic carbon content measurements confirmed the results obtained by LC/MS. Compared to the same nanoparticles prepared by another method, it was found that Gd doped CeO2 prepared by hydrothermal process was able to mineralize MB dye completely under UV light irradiation.

  15. Cerium oxide nanoparticles/multi-wall carbon nanotubes composites: Facile synthesis and electrochemical performances as supercapacitor electrode materials

    Science.gov (United States)

    Deng, Dongyang; Chen, Nan; Li, Yuxiu; Xing, Xinxin; Liu, Xu; Xiao, Xuechun; Wang, Yude

    2017-02-01

    Cerium oxide nanoparticles/multi-wall carbon nanotubes (MWCNTs) composites are synthesized by a facile hydrothermal method without any surfactant or template. The morphology and microstructure of samples are examined by scanning electron microscopy (SEM), transition electron microscopy (TEM), X-ray diffraction (XRD), Raman spectrum and X-ray photoelectron spectroscopy (XPS). Electrochemical properties of the MWCNTs, the pure CeO2, and the CeO2/MWCNTs nanocomposites electrodes are investigated by cyclic voltammetry (CV), galvanostatic charge/discharge (GDC) and electrochemical impedance spectroscopy (EIS) measurements. The CeO2/MWCNTs nanocomposite (at the mole ratio of 1:1) electrode exhibits much larger specific capacitance compared with both the MWCNTs electrode and the pure CeO2 electrode and significantly improves cycling stability compared to the pure CeO2 electrode. The CeO2/MWCNTs nanocomposite (at the mole ratio of 1:1) achieves a specific capacitance of 455.6 F g-1 at the current density of 1 A g-1. Therefore, the as prepared CeO2/MWCNTs nanocomposite is a promising electrode material for high-performance supercapacitors.

  16. Porous nano-cerium oxide wood chip biochar composites for aqueous levofloxacin removal and sorption mechanism insights.

    Science.gov (United States)

    Yi, Shengze; Sun, Yuanyuan; Hu, Xin; Xu, Hongxia; Gao, Bin; Wu, Jichun

    2017-01-14

    The adsorption removal of levofloxacin (LEV), a widely used fluoroquinolone antibiotic, by using the biochars derived from the pyrolysis of pine wood chip pretreated with cerium trichloride was investigated through batch sorption experiments and multiple characterization techniques. The differences in the basic physicochemical properties between Ce-impregnated biochars and the pristine biochars were confirmed by the analysis of elemental compositions, specific surface areas, energy dispersive spectrometry, X-ray diffraction, and thermo-gravimetry. FT-IR spectra of the pre- and post-sorption biochars confirmed the chemical adsorption for LEV sorption onto the biochars. Large shifts in the binding energy of Ce3d, O1s, C1s, and N1s regions on the pre- and post-sorption biochars indicated the surface complexation of LEV molecule onto the biochars. The binding species of Ce(4+) and Ce(3+) identified by X-ray photoelectron spectroscopy reflect the role of Ce oxides during sorption. Batch adsorption showed the significant enhancement of adsorption capacity for LEV after the Ce modification. Batch adsorption kinetic data fitted well with the pseudo-second-order model. Both the Langmuir and the Freundlich models reproduced the isotherm data well. Findings from this work indicated that Ce-impregnated biochars can be effective for the removal of aqueous LEV.

  17. Effect of nano-sized cerium-zirconium oxide solid solution on far-infrared emission properties of tourmaline powders

    Science.gov (United States)

    Guo, Bin; Yang, Liqing; Hu, Weijie; Li, Wenlong; Wang, Haojing

    2015-10-01

    Far-infrared functional nanocomposites were prepared by the co-precipitation method using natural tourmaline (XY3Z6Si6O18(BO3)3V3W, where X is Na+, Ca2+, K+, or vacancy; Y is Mg2+, Fe2+, Mn2+, Al3+, Fe3+, Mn3+, Cr3+, Li+, or Ti4+; Z is Al3+, Mg2+, Cr3+, or V3+; V is O2-, OH-; and W is O2-, OH-, or F-) powders, ammonium cerium(IV) nitrate and zirconium(IV) nitrate pentahydrate as raw materials. The reference sample, tourmaline modified with ammonium cerium(IV) nitrate alone was also prepared by a similar precipitation route. The results of Fourier transform infrared spectroscopy show that tourmaline modified with Ce and Zr has a better far-infrared emission property than tourmaline modified with Ce alone. Through characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), the mechanism for oxygen evolution during the heat process in the two composite materials was systematically studied. The XPS spectra show that Fe3+ ratio inside tourmaline modified with Ce alone can be raised by doping Zr. Moreover, it is showed that there is a higher Ce3+ ratio inside the tourmaline modified with Ce and Zr than tourmaline modified with Ce alone. In addition, XRD results indicate the formation of CeO2 and Ce1-xZrxO2 crystallites during the heat treatment and further TEM observations show they exist as nanoparticles on the surface of tourmaline powders. Based on these results, we attribute the improved far-infrared emission properties of Ce-Zr doped tourmaline to the enhanced unit cell shrinkage of the tourmaline arisen from much more oxidation of Fe2+ to Fe3+ inside the tourmaline caused by the change in the catalyst redox properties of CeO2 brought about by doping with Zr4+. In all samples, tourmaline modified with 7.14 wt.% Ce and 1.86 wt.% Zr calcined at 800∘C for 5 h has the best far-infrared emission property with the maximum emissivity value of 98%.

  18. Auxiliary power unit based on a solid oxide fuel cell and fuelled with diesel

    Science.gov (United States)

    Lawrence, Jeremy; Boltze, Matthias

    An auxiliary power unit (APU) is presented that is fuelled with diesel, thermally self-sustaining, and based on a solid oxide fuel cell (SOFC). The APU is rated at 1 kW electrical, and can generate electrical power after a 3 h warm-up phase. System features include a "dry" catalytic partial oxidation (CPOX) diesel reformer, a 30 cell SOFC stack with an open cathode, and a porous-media afterburner. The APU does not require a supply of external water. The SOFC stack is an outcome of a development partnership with H.C. Starck GmbH and Fraunhofer IKTS, and is discussed in detail in an accompanying paper.

  19. Effect of the Cerium Oxide (CeO2) on the Structural and Electrochemical Properties of the LaNi5Ce Metal Hydride Anode

    Science.gov (United States)

    Utami Hapsari, Ade; Zulfia, Anne; Raharjo, Jarot; Agustanhakri

    2017-07-01

    One of negative electrode, AB5-type alloy electrodes, have been extensively studied and applied in rechargeable Ni-MH batteries due to their excellent electrochemical characteristics. Some researchers have found that addition of rare earth oxides (La, Ce, Pr, Er, Tm, Yb) to AB5-type alloy (MH) electrode improves battery performance significantly. Cerium Oxide (CeO2) is a light rare earth oxide is widely obtained from the processing of tailings in mining activities. During this time, there is still little data for research applications of cerium oxide for electrode materials. In this paper, the effects of adding CeO2 on the performance metal hydride electrode were investigated. In order to study the effects of CeO2 on the performance of anode material, 1%, 2%, and 3% of weight ratio CeO2 was mixed to LaNi5 as an negative electrode. The powder mixtures were mechanically milled at a speed of rpm 240 for 2 hours using ball mill. The powder mixtures were characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM). Electrochemical characteristics were measured using electrochemical impedance spectroscopy (EIS). The powder mixing showed the presence of Ce atom substitution into LaNi5 structures that affect the electrochemical properties of the material. The addition of cerium oxide at LaNi5 increase of the value of impedance. However, the addition of the value of impedance at 1% CeO2 is not significant when compared with the addition of 2% and 3% CeO2 that actually make the electrochemical properties of LaNi5 worst. Although the addition of 1% CeO2 also slightly increases the impedance value of LaNi5, but the addition of 1% CeO2 showed increase the corrosion resistance than without the addition of CeO2 and the addition of 2% and 3% CeO2.

  20. Oxidation stability of rapeseed biodiesel/petroleum diesel blends

    DEFF Research Database (Denmark)

    Østerstrøm, Freja From; Anderson, James E.; Mueller, Sherry A.

    2016-01-01

    The effects of fuels, including contaminants such as fuel oxidation products, on vehicle fuel system materials are important for vehicle durability and operation. Fuel oxidation is accelerated at the elevated temperatures and pressures of vehicle fuel systems. An extended time-course study...

  1. Influence of particulate trap oxidizers on emission of mutagenic compounds by diesel automobiles.

    Science.gov (United States)

    Rasmussen, R E; Devillez, G; Smith, L R

    1989-06-01

    Diesel exhaust particles are known to contain mutagenic and carcinogenic chemicals. The aim of this study was to determine whether, and to what extent, catalytic particulate trap oxidizers on light-duty diesel engines may reduce the emission of particle-associated mutagenic chemicals into the environment. Exhaust particles were collected from Mercedes Benz and Volkswagen diesel automobiles, equipped with or without the manufacturer's exhaust traps, while running on a chassis dynamometer under specified load conditions. Exhaust particles were collected from a dilution tunnel onto 20" X 20" Teflon-coated fiberglass filters. Mutagenesis tests of dichloromethane (DCM) extracts of the particles were conducted using the Ames Salmonella bacterial test system. The mutation rate was calculated in terms of histidine revertants per mile of travel during a set of standard test cycles. With both vehicles the traps produced an 87-92% reduction in the total amount of particulate material collected by the filters. There was no significant change in the specific mutagenic activity (revertants per microgram of DCM particle extract) with or without the traps. These studies support the notion that installation of exhaust traps which reduce particulate emission on diesel-powered vehicles will also reduce the emission of particle-associated mutagenic and carcinogenic materials into the environment.

  2. Oxidative stress generated by diesel seawater contamination in the digestive gland of the Antarctic limpet, Nacella concinna

    Energy Technology Data Exchange (ETDEWEB)

    Ansaldo, M. [Instituto Antartico Argentino, Buenos Aires (Argentina); Najle, R. [Universidad del Centro de la Provincia de Buenos Aires, Tandil (Argentina). Facultad Cs. Veterinarias; Luquet, C.M. [Universidad de Buenos Aires, Ciudad Univ. (Argentina). Dept. de Biodiversidad y Biologia Experimental

    2005-05-01

    The aim of this work was to investigate the activity of antioxidant enzymes and oxidative damage in the digestive gland of the limpet Nacella concinna, and their suitability as biomarkers for hydrocarbon pollution in Antarctic coasts. Three groups of 30 individuals each were kept in seawater containing 0%, 0.05% or 0.1% diesel. Superoxide dismutase, catalase, glutathione S transferase and glutathione peroxidase activities, as well as lipid peroxidation and protein oxidation were studied in 18 animals of each group after 24, 48 and 168 h of exposure. The activity levels of most enzymes were increased by diesel in a dose-dependent manner. Glutathione peroxidase showed the most clear effect; its activity significantly increased in the 0.1% diesel group respect to the control. Lipid peroxidation and protein oxidation were significantly increased by diesel after 168 h. Both variables were higher in the group exposed to the lowest dose. (author)

  3. Antioxidant Effect on Oxidation Stability of Blend Fish Oil Biodiesel with Vegetable Oil Biodiesel and Petroleum Diesel Fuel

    Directory of Open Access Journals (Sweden)

    M. Hossain

    2013-06-01

    Full Text Available Two different phenolic synthetic antioxidants were used to improve the oxidation stability of fish oil biodiesel blends with vegetable oil biodiesel and petroleum diesel. Butylhydroxytoluene (BHT most effective for improvement of the oxidation stability of petro diesel, whereas  tert-butylhydroquinone (TBHQ showed good performance in fish oil biodiesel. Fish oil/Rapeseed oil biodiesel mixed showed some acceptable results in higher concentration ofantioxidants. TBHQ showed better oxidation stability than BHT in B100 composition. In fish oil biodiesel/diesel mixed fuel, BHT was more effective antioxidant than TBHQ to increase oxidationstability because BHT is more soluble than TBHQ. The stability behavior of biodiesel/diesel blends with the employment of the modified Rancimat method (EN 15751. The performance ofantioxidants was evaluated for treating fish oil biodiesel/Rapeseed oil biodiesel for B100, and blends with two type diesel fuel (deep sulfurization diesel and automotive ultra-low sulfur or zero sulfur diesels. The examined blends were in proportions of 5, 10, 15, and 20% by volume of fish oilbiodiesel.

  4. Study of Degradation Kinetics of Parathion Methyl On Mixed Nanocrystalline Titania-Zirconium and Titania-Cerium Oxides

    Science.gov (United States)

    Kuráň, Pavel; Pšenička, Martin; Šťastný, Martin; Benkocká, Monika; Janoš, Pavel

    2016-10-01

    The unique surface properties of some nanocrystalline metal oxides and their application for removal of various toxic compounds were reported in early 1990s. Recently, a reliable method for the preparation of reactive cerium dioxide sorbent and its application for degradation of the organophosphate pesticides, such as parathion methyl, chlorpyrifos, dichlofenthion, fenchlorphos, and prothiofos, as well as of some chemical warfare agents-nerve gases soman and O-ethyl S-[2-(diisopropylamino) ethyl] methylphosphonothioate (VX) was published. This paper reports on the kinetics study of degradation of parathion methyl as a representative organophosphate on nanocrystalline metal oxides TiO2, ZrO2, CeO2 and their mixtures in different molar ratios of particular elements. The tested sorbents except of CeO2 were prepared by different methods (e.g. sol-gel, precipitation) in cooperation with Institute of Inorganic Chemistry (Rez, Czech Republic). The degradation kinetics of parathion methyl on tested sorbents was followed by HPLC equipped with diode array detector. The basic kinetics parameters (half-lives of parathion methyl degradation, rate constants of degradation product formation) were calculated for each sorbent from Weber-Morris equation of 1st order diffusion kinetic model. The results proved the ability of prepared sorbents to degrade parathion methyl under formation of 4-nitrophenol as the main degradation product. The most efficient sorbents were TiCe (2:8), TiCe (1:1), TiCe (0:1) (50-70 %) followed by TiZr (1:1), TiCe (8:2), TiZr (8:2), TiZr (2:8) (20-30%) and TiO2, ZrO2 (less than 5 %).

  5. Effects of Cerium and Titanium Oxide Nanoparticles in Soil on the Nutrient Composition of Barley (Hordeum vulgare L. Kernels

    Directory of Open Access Journals (Sweden)

    Filip Pošćić

    2016-06-01

    Full Text Available The implications of metal nanoparticles (MeNPs are still unknown for many food crops. The purpose of this study was to evaluate the effects of cerium oxide (nCeO2 and titanium oxide (nTiO2 nanoparticles in soil at 0, 500 and 1000 mg·kg−1 on the nutritional parameters of barley (Hordeum vulgare L. kernels. Mineral nutrients, amylose, β-glucans, amino acid and crude protein (CP concentrations were measured in kernels. Whole flour samples were analyzed by ICP-AES/MS, HPLC and Elemental CHNS Analyzer. Results showed that Ce and Ti accumulation under MeNPs treatments did not differ from the control treatment. However, nCeO2 and nTiO2 had an impact on composition and nutritional quality of barley kernels in contrasting ways. Both MeNPs left β-glucans unaffected but reduced amylose content by approximately 21%. Most amino acids and CP increased. Among amino acids, lysine followed by proline saw the largest increase (51% and 37%, respectively. Potassium and S were both negatively impacted by MeNPs, while B was only affected by 500 mg nCeO2·kg−1. On the contrary Zn and Mn concentrations were improved by 500 mg nTiO2·kg−1, and Ca by both nTiO2 treatments. Generally, our findings demonstrated that kernels are negatively affected by nCeO2 while nTiO2 can potentially have beneficial effects. However, both MeNPs have the potential to negatively impact malt and feed production.

  6. Active oxygen by Ce–Pr mixed oxide nanoparticles outperform diesel soot combustion Pt catalysts

    OpenAIRE

    Guillén Hurtado, Noelia; Garcia-Garcia, Avelina; Bueno López, Agustín

    2015-01-01

    A Ce0.5Pr0.5O2 mixed oxide has been prepared with the highest surface area and smallest particle size ever reported (125 m2/g and 7 nm, respectively), also being the most active diesel soot combustion catalyst ever tested under realistic conditions if catalysts forming highly volatile species are ruled out. This Ce–Pr mixed oxide is even more active than a reference platinum-based commercial catalyst. This study provides an example of the efficient participation of oxygen species released by ...

  7. Quaternary Oxide of Cerium, Terbium, Praseodymium and Zirconium for Three-Way Catalysts

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Oxygen storagecapacity (OSC), oxygen buffer capacity (OBC), X-ray diffraction and electron diffraction pattern, high resolution electron microscopy were used to study the quaternary oxides, i.e., of Ce, Tb, Pr and Zr. (Ce0.6Tb0.2Zr0.2O2-δ and Ce0.6Pr0.2Zr0.2O2-δ). OSC and OBC data indicate that these oxides have very good oxygen transfer capacity (OTC) and their pseudo-solid solutions exhibit fluorite-type structure. These oxides may act as a good candidate for three-way catalysts (TWC).

  8. Storage capacity and oxygen mobility in mixed oxides from transition metals promoted by cerium

    Science.gov (United States)

    Perdomo, Camilo; Pérez, Alejandro; Molina, Rafael; Moreno, Sonia

    2016-10-01

    The oxygen mobility and storage capacity of Ce-Co/Cu-MgAl or Ce-MgAl mixed oxides, obtained by hydrotalcite precursors, were evaluated using Toluene-temperature-programmed-reaction, 18O2 isotopic exchange and O2-H2 titration. The presence of oxygen vacancies-related species was evaluated by means of Electron Paramagnetic Resonance. A correlation was found between the studied properties and the catalytic activity of the oxides in total oxidation processes. It was evidenced that catalytic activity depends on two related processes: the facility with which the solid can be reduced and its ability to regenerate itself in the presence of molecular oxygen in the gas phase. These processes are enhanced by Cu-Co cooperative effect in the mixed oxides. Additionally, the incorporation of Ce in the Co-Cu catalysts improved their oxygen transport properties.

  9. Oxidation of diesel-generated volatile organic compounds in the selective catalytic reduction process

    Energy Technology Data Exchange (ETDEWEB)

    Koebel, M.; Elsener, M. [Paul Scherrer Inst., Villigen (Switzerland). Combustion Research

    1998-10-01

    The main part of the VOCs (volatile organic compounds) contained in diesel exhaust ({approx}80%) is oxidized to CO and CO{sub 2} over an SCR (selective catalytic reduction) catalyst. CO is the major product of this oxidation, representing about 50--70% of the formed products (CO + CO{sub 2}). This preferential formation of CO leads to a pronounced increase of CO emissions when an SCR process is added to a diesel engine. A small fraction of the VOCs is selectively oxidized to carboxylic acids over the SCR catalyst. This selectivity is due to the acidic properties of the catalyst causing the preferential desorption at the oxidation state of the acid. The main products of these oxidation reactions are the lower monocarboxylic acids and some dicarboxylic acids forming stable anhydrides, especially maleic and phthalic acid. The highest emissions of these acids are found at low temperatures; they decrease at higher temperatures. Formic acid is preferentially decomposed into carbon monoxide and water. It must therefore be assumed that the strong increase of CO mentioned above is due to a mechanism involving the thermal decomposition of formic acid formed from various primary VOCs.

  10. Emissions of nitrogen oxides and particulates of diesel vehicles

    NARCIS (Netherlands)

    Kadijk, G.; Ligterink, N.E.; Mensch, P. van; Spreen, J.S.; Vermeulen, R.J.; Vonk, W.A.

    2015-01-01

    In real-world conditions, modern Euro VI heavy-duty vehicles produce an average of ten times less nitrogen oxide (NOx)emissions than previous generations of Euro IV and Euro V heavy-duty vehicles. However, Euro 6 passenger cars and light commercial vehicles present an entirely different picture sinc

  11. Storage capacity and oxygen mobility in mixed oxides from transition metals promoted by cerium

    Energy Technology Data Exchange (ETDEWEB)

    Perdomo, Camilo [Estado Sólido y Catálisis Ambiental (ESCA), Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia, Carrera 30 45-03, Bogotá (Colombia); Pérez, Alejandro [Grupo de Investigación Fitoquímica (GIFUJ), Departamento de Química, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7 No. 43-82, Bogotá D.C (Colombia); Molina, Rafael [Estado Sólido y Catálisis Ambiental (ESCA), Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia, Carrera 30 45-03, Bogotá (Colombia); Moreno, Sonia, E-mail: smorenog@unal.edu.co [Estado Sólido y Catálisis Ambiental (ESCA), Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia, Carrera 30 45-03, Bogotá (Colombia)

    2016-10-15

    Highlights: • Ce addition to the catalysts improves the availability of oxygen in the materials. • Mixed oxide with Co and Cu exhibits the best oxygen transport properties. • Co presence improves O{sub 2} mobility in the catalysts. • The presence of Cu in the solids improves redox properties. - Abstract: The oxygen mobility and storage capacity of Ce-Co/Cu-MgAl or Ce–MgAl mixed oxides, obtained by hydrotalcite precursors, were evaluated using Toluene-temperature-programmed-reaction, {sup 18}O{sub 2} isotopic exchange and O{sub 2}-H{sub 2} titration. The presence of oxygen vacancies-related species was evaluated by means of Electron Paramagnetic Resonance. A correlation was found between the studied properties and the catalytic activity of the oxides in total oxidation processes. It was evidenced that catalytic activity depends on two related processes: the facility with which the solid can be reduced and its ability to regenerate itself in the presence of molecular oxygen in the gas phase. These processes are enhanced by Cu-Co cooperative effect in the mixed oxides. Additionally, the incorporation of Ce in the Co-Cu catalysts improved their oxygen transport properties.

  12. Effect of temperature on the crystallite size of Lanthanum Cerium Oxide (La2Ce2O7 and its optical properties

    Directory of Open Access Journals (Sweden)

    Hozefa Tinwala

    2013-03-01

    Full Text Available The effect of the calcination process on the crystallite size and optical properties of Lanthanum Cerium Oxide (La2Ce2O7 nanopowders synthesized using co-precipitation process were reported. X-ray diffraction analysis revealed that the synthesized nanopowders calcined at various temperatures have cubic fluorite phase. Thermal Gravimetric Analysis (TGA, X-ray Diffraction (XRD, Energy Dispersive Spectroscopy (EDS, Transmission Electron Microscopy (TEM, Laser Raman Spectroscopy, and UVvisible spectroscopy were utilized to characterize phase structure and morphology of the products.

  13. A fully spray-coated fuel cell membrane electrode assembly using Aquivion ionomer with a graphene oxide/cerium oxide interlayer

    Science.gov (United States)

    Breitwieser, Matthias; Bayer, Thomas; Büchler, Andreas; Zengerle, Roland; Lyth, Stephen M.; Thiele, Simon

    2017-05-01

    A novel multilayer membrane electrode assembly (MEA) for polymer electrolyte membrane fuel cells (PEMFCs) is fabricated in this work, within a single spray-coating device. For the first time, direct membrane deposition is used to fabricate a PEMFC by spraying the short-side-chain ionomer Aquivion directly onto the gas diffusion electrodes. The fully sprayed MEA, with an Aquivion membrane 10 μm in thickness, achieved a high power density of 1.6 W/cm2 for H2/air operation at 300 kPaabs. This is one of the highest reported values for thin composite membranes operated in H2/air atmosphere. By the means of confocal laser scanning microscopy, individual carbon fibers from the gas diffusion layer are identified to penetrate through the micro porous layer (MPL), likely causing a low electrical cell resistance in the range of 150 Ω cm2 through the thin sprayed membranes. By spraying a 200 nm graphene oxide/cerium oxide (GO/CeO2) interlayer between two layers of Aquivion ionomer, the impact of the electrical short is eliminated and the hydrogen crossover current density is reduced to about 1 mA/cm2. The peak power density of the interlayer-containing MEA drops only by 10% compared to a pure Aquivion membrane of similar thickness.

  14. Modeling of Nitric Oxide Formation in Single Cylinder Direct Injection Diesel Engine Using Diesel-Water Emulsion

    Directory of Open Access Journals (Sweden)

    K. Kannan

    2009-01-01

    Full Text Available Problem statement: Water injection into the combustion chamber of diesel engine found to be one of best method for in-cylinder control of NOx formation. Approach: The combustion of water-diesel emulsion in diesel engine was simulated using a computer program to estimate the heat release rate, cylinder pressure, brake thermal efficiency, brake specific fuel consumption and NO formation. Results: The numerical simulation was performed at different equivalence ratios, engine speeds and water percentages. The numerical simulation was preferred to study the combustion behavior and emission of diesel engine because the experimental investigations were time consuming and costly affair. Conclusion/Recommendations: Experiments also conducted to validate the predicted results of computer simulation. Though the zero dimensional simulation models predicted NO formation during combustion process, the first appearance of NO could not be identified using this method which can be solved by CFD technique.

  15. Influence of the synthesis parameters on the physico-chemical and catalytic properties of cerium oxide for application in the synthesis of diethyl carbonate

    Energy Technology Data Exchange (ETDEWEB)

    Leino, Ewelina; Kumar, Narendra; Mäki-Arvela, Päivi; Aho, Atte [Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, 20500 Turku/Åbo (Finland); Kordás, Krisztián [Chemical–Biological Centre, Department of Chemistry, Technical Chemistry, Umeå University, SE-90187 Umeå (Sweden); Laboratory of Microelectronics and Materials Physics, EMPART Research Group of Infotech Oulu, University of Oulu, PL 4500, 90014 Oulu (Finland); Leino, Anne-Riikka [Laboratory of Microelectronics and Materials Physics, EMPART Research Group of Infotech Oulu, University of Oulu, PL 4500, 90014 Oulu (Finland); Shchukarev, Andrey [Chemical–Biological Centre, Department of Chemistry, Technical Chemistry, Umeå University, SE-90187 Umeå (Sweden); Murzin, Dmitry Yu., E-mail: dmurzin@abo.fi [Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, 20500 Turku/Åbo (Finland); Mikkola, Jyri-Pekka [Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, 20500 Turku/Åbo (Finland); Chemical–Biological Centre, Department of Chemistry, Technical Chemistry, Umeå University, SE-90187 Umeå (Sweden)

    2013-12-16

    Synthesis of cerium (IV) oxide by means of room temperature precipitation method was carried out. The effect of preparation variables such as synthesis time, calcination temperature and pH of the solution on resulting CeO{sub 2} properties was discussed. Moreover, the comparison of CeO{sub 2} samples prepared in a static and rotation mode of synthesis is presented. The solid catalysts were characterized by means of X-ray powder diffraction, scanning electron microscopy, transmission electron microscope, nitrogen physisorption, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy using pyridine as a probe molecule and temperature programmed desorption of CO{sub 2}. Significant variations in physico-chemical properties of CeO{sub 2} by varying the preparation conditions were observed. Furthermore, the catalytic performances of CeO{sub 2} catalysts were compared in the synthesis of diethyl carbonate starting from ethanol and CO{sub 2} using butylene oxide as a dehydrating agent. The dependence of CeO{sub 2} properties on its catalytic activity is evaluated in detail. - Highlights: • Synthesis of cerium (IV) oxide by precipitation method. • Influence of synthesis time, calcination temperature, mode of stirring and solution pH on properties. • Characterization by XRD, SEM, TEM, nitrogen physisorption, XPS, FTIR. • Catalytic performance diethyl carbonate synthesis from ethanol and CO{sub 2}.

  16. Poly(vinylpyrrolidone) as dispersing agent for cerium-gadolinium oxide (CGO) suspensions

    DEFF Research Database (Denmark)

    Marani, Debora; Sudireddy, Bhaskar Reddy; Nielsen, Lotte

    2016-01-01

    The behaviour of selected poly(vinylpyrrolidone) grades to act as dispersant for ethanol-based ceriumgadolinium oxide suspensions was investigated and related to the molecular weight characteristics. The number, weight, and z-average molecular weights Mn, Mw, and Mz were determined by gel...

  17. Altered Nitric Oxide Bioavailability Contributes to Diesel Exhaust Inhalation‐Induced Cardiovascular Dysfunction in Man

    Science.gov (United States)

    Langrish, Jeremy P.; Unosson, Jon; Bosson, Jenny; Barath, Stefan; Muala, Ala; Blackwell, Scott; Söderberg, Stefan; Pourazar, Jamshid; Megson, Ian L.; Treweeke, Andrew; Sandström, Thomas; Newby, David E.; Blomberg, Anders; Mills, Nicholas L.

    2013-01-01

    Background Diesel exhaust inhalation causes cardiovascular dysfunction including impaired vascular reactivity, increased blood pressure, and arterial stiffness. We investigated the role of nitric oxide (NO) bioavailability in mediating these effects. Methods and Results In 2 randomized double‐blind crossover studies, healthy nonsmokers were exposed to diesel exhaust or filtered air. Study 1: Bilateral forearm blood flow was measured during intrabrachial infusions of acetylcholine (ACh; 5 to 20 μg/min) and sodium nitroprusside (SNP; 2 to 8 μg/min) in the presence of the NO clamp (NO synthase inhibitor NG‐monomethyl‐l‐arginine (l‐NMMA) 8 μg/min coinfused with the NO donor SNP at 90 to 540 ng/min to restore basal blood flow). Study 2: Blood pressure, arterial stiffness, and cardiac output were measured during systemic NO synthase inhibition with intravenous l‐NMMA (3 mg/kg). Following diesel exhaust inhalation, plasma nitrite concentrations were increased (68±48 versus 41±32 nmol/L; P=0.006) despite similar l‐NMMA–induced reductions in basal blood flow (−20.6±14.7% versus −21.1±14.6%; P=0.559) compared to air. In the presence of the NO clamp, ACh and SNP caused dose‐dependent vasodilatation that was not affected by diesel exhaust inhalation (P>0.05 for both). Following exposure to diesel exhaust, l‐NMMA caused a greater increase in blood pressure (P=0.048) and central arterial stiffness (P=0.007), but reductions in cardiac output and increases in systemic vascular resistance (P>0.05 for both) were similar to those seen with filtered air. Conclusions Diesel exhaust inhalation disturbs normal vascular homeostasis with enhanced NO generation unable to compensate for excess consumption. We suggest the adverse cardiovascular effects of air pollution are, in part, mediated through reduced NO bioavailability. Clinical Trial Registration URL: http://www.ClinicalTrials.gov. Unique identifiers: NCT00845767 and NCT01060930. PMID:23525434

  18. Selective side-chain oxidation of alkyl aromatic compounds catalyzed by cerium modified silver catalysts

    DEFF Research Database (Denmark)

    Beier, Matthias Josef; Schimmoeller, Bjoern; Hansen, Thomas Willum

    2010-01-01

    an elevated pressure was required. Carboxylic acids, such as benzoic acid or p-toluic acid, additionally increased the reaction rate while CeO2 could act both as a promoter and an inhibitor depending on the substrate and the reaction conditions. Silver catalysts were prepared both by standard impregnation......Silver supported on silica effectively catalyzes the aerobic side-chain oxidation of alkyl aromatic compounds under solvent-free conditions. Toluene, p-xylene, ethylbenzene and cumene were investigated as model substrates. Typically, the reaction was performed at ambient pressure; only for toluene...... and flame spray pyrolysis. Addition of a Ce precursor to the FSP catalyst resulted in significantly smaller silver particles. Ce-doped FSP catalysts in general exhibited a superior catalytic performance with TONs up to 2000 except for cumene oxidation that appeared to proceed mainly by homogeneous catalysis...

  19. Investigation of ionic conductivity of lanthanum cerium oxide nano crystalline powder synthesized by co precipitation method

    Science.gov (United States)

    Tinwala, Hozefa; Shah, Patij; Siddhapara, Kirit; Shah, Dimple; Menghani, Jyoti

    2016-10-01

    Lanthanum (La) doped Ceria (CeO2) electrolyte has attracted considerable interest, as a candidate material for solid oxide fuel cells (SOFCs). The ionic conductivity of La doped CeO2 system (La2Ce2O7) nano-particles synthesized by the co-precipitation method has been investigated. The cubic fluorite structure was observed from the structural analysis of the material. Morphology of the sintered pellets are observed by scanning electron microscope (SEM), respectively. From the results of impedance spectroscopy from temperature range of room temperature to 400 °C, the oxide ion conductivity due to proton charge carrier was observed. Thermogravimetric analysis (TGA) was performed on the material to check stability of phase at high temperature.

  20. Direct Comparison of the X-Ray Emission and Absorption of Cerium Oxide

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, J G; Yu, S W; Chung, B W; Waddill, G D; Denlinger, J D

    2010-11-24

    Bremstrahlung Isochromat Spectroscopy (BIS). The XES spectra were collected using a Specs electron gun for the excitation and the XES 350 grating monochromator and channel plate system from Scienta as the photon detection. Spectra were collected in 'normal mode,' where the electron gun kinetic energy (KE) and the energy position of the center of the channel plate were both fixed and the energy distribution in the photon (hv) spectrum was derived from the intensities distributed across the channel plate detector in the energy dispersal direction. The polycrystalline Ce sample was oxidized by exposure to air at ambient pressures. After introduction to the ultra-high vacuum system, the oxidized sample was bombarded with Ar, to clean the topmost surface region and stabilize the surface and near surface regions. Although CeO{sub 2} would be the thermodynamically preferred composition in an oxygen rich environment, the combination of a vacuum environment and ion etching may have driven the near surface region into a Ce{sub 2}O{sub 3} stoichiometry. XES data collection occurred with the sample at or near room temperature. The base pressure of the system was 3 x 10{sup -10} torr, but the pressure changed depending the energy and current of the electron gun. For example, with the XES measurements at KE = 3KeV, the pressure was approximately 8 to 9 x 10{sup -10} torr and the excitation current to the sample was typically 0.01 mA. More detail of the sample preparation and analysis can be found in Reference 1. The XAS experiments were performed at Beamline 8 of the Advance Light Source, as part of a larger collaboration. The ex situ sample used at the ALS was prepared in a fashion similar to that described above. X-ray Emission Spectroscopy (XES) and X-ray Absorption Spectroscopy (XAS), have been used to investigate the photon emission and absorption associated with the Ce3d{sub 5/2} and Ce3d{sub 3/2} core-levels in CeOxide. A comparison of the two processes and

  1. 硫酸溶液中胶束催化Ce(IV)氧化D-甘露糖%Micelle Catalyzed Oxidation of D-Mannose by Cerium (Ⅳ) in Sulfuric Acid

    Institute of Scientific and Technical Information of China (English)

    KABIR-UD-DIN; ALI Mohd. Sajid; KHAN Zaheer

    2008-01-01

    Kinetics of D-mannose oxidation by cerium (IV) was studied in a sulfuric acid medium at 40℃ both in absence and presence of ionic micelles. In both cases, the rate of the reaction was first-order in D-mannose and in cerium(Ⅳ), which decreased with increasing [H2SO4]. This suggested that the redox reaction followed the same mechanism. The reaction proceeded through formation of an intermediate complex, which was proved by kinetic method. The complex underwent slow unimolecular decomposition to a free radical that reacted with cerium (Ⅳ) to afford the product. The catalytic role of cationic cetyltrimethylammonium bromide (CTAB) micelles was best explained by the Menger-Portnoy model. The study of the effect of CTAB also indicated that a negatively charged species was reactive form of cerium (Ⅳ). From the kinetic data, micelle-cerium (Ⅳ) binding and rate constants in micellar medium were evaluated.The anionic micelle of sodium dodecyl sulfate plays no catalytic role. The oxidation has the rate expression: --d[Ce(Ⅳ)]= k1Kcl[D-mannose] [Ce(Ⅳ)]dt Different activation parameters for micelle catalyzed and uncatalyzed paths were also calculated and discussed.

  2. Calculations of thermodynamic data from spectroscopic data for oxides for cerium and neodymium

    Energy Technology Data Exchange (ETDEWEB)

    Sunder, S.; Lemire, R.J

    2000-01-01

    A code to calculate thermodynamic functions of an ideal gas (at 1 atm pressure) from its spectroscopic data using statistical mechanics methods was commissioned, tested and verified. The code was used to calculate the thermodynamic functions for three fission-product oxides, Ce0{sub 2}, Ce{sub 2}0{sub 2} and NdO{sub 2}, for temperatures between 100 K and 3000 K and 0.1 MPa. High-temperature thermodynamic data of fission products are needed to calculate the source terms under accident conditions using fuel safety codes such as CHMWRK and F*A*C*T. (author)

  3. Role of the oxidation state of cerium on the ceria surfaces for silicate adsorption

    Science.gov (United States)

    Seo, Jihoon; Moon, Jinok; Kim, Joo Hyun; Lee, Kangchun; Hwang, Junha; Yoon, Heesung; Yi, Dong Kee; Paik, Ungyu

    2016-12-01

    In this study, we have investigated the role of the Ce oxidation state (Ce3+/Ce4+) on the CeO2 surfaces for silicate adsorption. In aqueous medium, the Ce3+ sites lead to the formation of -OH groups at the CeO2 surface through H2O dissociation. Silicate ions can adsorb onto the CeO2 surface through interaction with the -OH groups (-Ce-OH- + -Si-O- ↔ -Ce-O-Si- + OH-). As the Ce3+ concentration increased from 19.3 to 27.6%, the surface density of -OH group increased from 0.34 to 0.72 OH/nm2. To evaluate the adsorption behaviors of silicate ions onto CeO2 NPs, we carried out an adsorption isothermal analysis, and the adsorption isotherm data followed the Freundlich model. The Freundlich constant for the relative adsorption capacity (KF) and adsorption intensity (1/n) indicated that CeO2 NPs with high Ce3+ concentration show higher adsorption affinity with silicate ions. As a result, we have demonstrated that the Ce oxidation state (Ce3+/Ce4+) on the CeO2 surface can have a significant influence on the silicate adsorption.

  4. Ruthenium versus platinum on cerium materials in wet air oxidation of acetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Gaalova, J. [Institute of Chemical Process Fundamentals of the CAS, Rozvojova 135, 165 02 Prague 6, CZ (Czech Republic); Barbier, J., E-mail: Jacques.barbier.jr@univ-poitiers.fr [University of Poitiers, LACCO UMR 6503, Laboratoire de Catalyse par les Metaux, 40 Avenue du Recteur Pineau, F-86022 POITIERS Cedex (France); Rossignol, S. [University of Limoges, ENSCI, 47 Avenue Albert Thomas 87000 Limoges France (France)

    2010-09-15

    This study was a comparison between Ru-catalysts and similar, previously investigated, Pt-catalysts. In this paper, ruthenium catalysts for catalytic wet air oxidation are prepared, characterized and tested. Both catalysts were supported on commercial CeO{sub 2} as well as mixed oxide Zr{sub 0.1}(Ce{sub 0.75}Pr{sub 0.25}){sub 0.9}O{sub 2}. The catalysts were characterized by measuring the oxygen storage capacities (OSC), BET, XRD, FTIR and chemisorption of hydrogen. In addition, the effect of sintering (treatments under H{sub 2}) was compared with both of the catalysts. The comparison of the results showed that initial intrinsic activity of ruthenium is not significantly influenced by the type of the support, which is contrast to platinum. Furthermore, the particle size of Ru had an important effect on CWAO activity: the higher the particle size, the better the activity. This was different with Pt-catalysts, where the optimal particle size was smaller, having about 15% of metal dispersion.

  5. Experimental investigation into the oxidation reactivity and nanostructure of particulate matter from diesel engine fuelled with diesel/polyoxymethylene dimethyl ethers blends

    Science.gov (United States)

    Yang, Hao; Li, Xinghu; Wang, Yan; Mu, Mingfei; Li, Xuehao; Kou, Guiyue

    2016-11-01

    This paper focuses on oxidation reactivity and nanostructural characteristics of particulate matter (PM) emitted from diesel engine fuelled with different volume proportions of diesel/polyoxymethylene dimethyl ethers (PODEn) blends (P0, P10 and P20). PM was collected using a metal filter from the exhaust manifold. The collected PM samples were characterized using thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The TGA results indicated that the PM produced by P20 had the highest moisture and volatility contents and the fastest oxidation rate of solid carbon followed by P10 and P0 derived PM. SEM analysis showed that PM generated from P20 was looser with a lower mean value than PM emitted from P10 and P0. Quantitative analysis of high-resolution TEM images presented that fringe length was reduced along with increased separation distance and tortuosity with an increase in PODEn concentration. These trends improved the oxidation reactivity. According to Raman spectroscopy data, the intensity, full width at half-maximum and intensity ratio of the bands also changed demonstrating that PM nanostructure disorder was correlated with a faster oxidation rate. The results show the use of PODEn affects the oxidation reactivity and nanostructure of PM that is easier to oxidize.

  6. Preparation of AAO-CeO2 nanotubes and their application in electrochemical oxidation desulfurization of diesel

    Science.gov (United States)

    Du, Xiaoqing; Yang, Yumeng; Yi, Chenxi; Chen, Yu; Cai, Chao; Zhang, Zhao

    2017-02-01

    The coaxial arrays of AAO-CeO2 NTs have been successfully galvanostatically deposited on an anode, characterized and adopted as a catalyst for removing organic sulfurs from diesel. The influence of the main electrochemical oxidation factors on the efficiency of desulfurization have also been investigated. The results show that the fabrication process of AAO-CeO2 NTs is accompanied by the formation of a new phase, namely Al3Ce, and the main oxidation products of the diesel are soluble inorganic sulphides, especially Ce2(SO4)3. When compared with dibenzothiophene and 4, 6-dimethyldibenzothiophene, benzothiophene is much more easily removed, with a removal efficiency that reaches 87.2%. Finally, a possible electrochemical oxidation desulfurization pathway for diesel is proposed.

  7. Comparison of Preparation Methods of Copper Based PGMFree Diesel-Soot Oxidation Catalysts

    Directory of Open Access Journals (Sweden)

    R. Prasad

    2011-05-01

    Full Text Available CuO-CeO2 systems have been proposed as a promising catalyst for low temperature diesel-soot oxidation. CuO-CeO2 catalysts prepared by various methods were examined for air oxidation of the soot in a semi batch tubular flow reactor. The air oxidation of soot was carried out under tight contact with soot/catalyst ratio of 1/10. Air flow rate was 150 ml/min, soot-catalyst mixture was 110 mg, heating rate was 5 0C/min. Prepared catalysts were calcined at 500 0C and their stability was examined by further heating to 800 0C for 4 hours. It was found that the selectivity of all the catalysts was nearly 100% to CO2 production. It was observed that the activity and stability of the catalysts greatly influenced by the preparation methods. The strong interaction between CuO and CeO2 is closely related to the preparation route that plays a crucial role in the soot oxidation over the CuO-CeO2 catalysts. The ranking order of the preparation methods of the catalysts in the soot oxidation performance is as follows: sol-gel > urea nitrate combustion > Urea gelation method > thermal decomposition > co-precipitation. Copyright © 2011 BCREC UNDIP. All rights reserved.(Received: 27th June 2010, Revised: 7th August 2010; Accepted: 13rd October 2010[How to Cite: R. Prasad, V.R. Bella. (2011. Comparison of Preparation Methods of Copper Based PGMFree Diesel-Soot Oxidation Catalysts. Bulletin of Chemical Reaction Engineering and Catalysis, 6(1: 15-21. doi:10.9767/bcrec.6.1.822.15-21][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.1.822.15-21 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/822 | View in 

  8. Cerium oxide as conversion coating for the corrosion protection of aluminum

    Directory of Open Access Journals (Sweden)

    JELENA GULICOVSKI

    2013-11-01

    Full Text Available CeO2 coatings were formed on the aluminum after Al surface preparation, by dripping the ceria sol, previously prepared by forced hydrolysis of Ce(NO34. The anticorrosive properties of ceria coatings were investigated by the electrochemical impedance spectroscopy (EIS during the exposure to 0.03 % NaCl. The morphology of the coatings was examined by the scanning electron microscopy (SEM. EIS data indicated considerably larger corrosion resistance of CeO2-coated aluminum than for bare Al. The corrosion processes on Al below CeO2 coating are subjected to more pronounced diffusion limitations in comparison to the processes below passive aluminum oxide film, as the consequence of the formation of highly compact protective coating. The results show that the deposition of ceria coatings is an effective way to improve corrosion resistance for aluminum.

  9. Simultaneous catalytic removal of NOx and diesel soot particulate over perovskite-type oxides and supported Ag catalysts

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A series of perovskite-type oxides and supported Ag catalysts were prepared,and characterized by X-ray diffraction (XRD) and Xray photoelectron spectroscopy (XPS).The catalytic activities of the catalysts as well as influencing factors on catalytic activity have been investigated for the simultaneous removal of NOx and diesel soot particulate.An increase in catalytic activity for the selective reduction of NOx was observed with Ag addition in these perovskite oxides,especially with 5% Ag loading.This catalyst could be a promising candidate of catalytic material for the simultaneous elimination of NOx and diesel soot.

  10. Recovery of microbial diversity and activity during bioremediation following chemical oxidation of diesel contaminated soils.

    Science.gov (United States)

    Sutton, Nora B; Langenhoff, Alette A M; Lasso, Daniel Hidalgo; van der Zaan, Bas; van Gaans, Pauline; Maphosa, Farai; Smidt, Hauke; Grotenhuis, Tim; Rijnaarts, Huub H M

    2014-03-01

    To improve the coupling of in situ chemical oxidation and in situ bioremediation, a systematic analysis was performed of the effect of chemical oxidation with Fenton's reagent, modified Fenton's reagent, permanganate, or persulfate, on microbial diversity and activity during 8 weeks of incubation in two diesel-contaminated soils (peat and fill). Chemical oxidant and soil type affected the microbial community diversity and biodegradation activity; however, this was only observed following treatment with Fenton's reagent and modified Fenton's reagent, and in the biotic control without oxidation. Differences in the highest overall removal efficiencies of 69 % for peat (biotic control) and 59 % for fill (Fenton's reagent) were partially explained by changes in contaminant soil properties upon oxidation. Molecular analysis of 16S rRNA and alkane monooxygenase (alkB) gene abundances indicated that oxidation with Fenton's reagent and modified Fenton's reagent negatively affected microbial abundance. However, regeneration occurred, and final relative alkB abundances were 1-2 orders of magnitude higher in chemically treated microcosms than in the biotic control. 16S rRNA gene fragment fingerprinting with DGGE and prominent band sequencing illuminated microbial community composition and diversity differences between treatments and identified a variety of phylotypes within Alpha-, Beta-, and Gammaproteobacteria. Understanding microbial community dynamics during coupled chemical oxidation and bioremediation is integral to improved biphasic field application.

  11. Unfiltered Diesel Engine Exhaust Treatment by Discharge Plasma:Effect of Soot Oxidation

    Institute of Scientific and Technical Information of China (English)

    B. S. Rajanikanth; Subhankar Das; A. D. Srinivasan

    2004-01-01

    A cascaded system of electrical discharges (Non-thermal plasma), catalyst and adsorption process was investigated for the removal of oxides of nitrogen (NO x) and carbon monoxide (CO) from a Diesel engine raw exhaust. The three processes were separately studied first, and then the cascaded processes, namely plasma-catalyst and plasma-adsorbent, were investigated. In this paper main emphasis was laid on the effect of carbonaceous soot oxidation on the plasma treatment process. While the cascaded plasma-catalyst process exhibits a higher CO removal, the cascaded plasma-adsorbent process exhibits a higher NO x removal. The experiments were conducted under no-load. The plasma and adsorbent reactors were kept at room temperature throughout the experiment while the catalyst reactor was kept at 200oC / 300oC.

  12. Modified semi-coke-supported cerium oxide-doped zinc ferrites for the removal of H{sub 2}S from coal gas

    Energy Technology Data Exchange (ETDEWEB)

    Mi, J.; Guo, T.; Zhu, Y.; Wang, J. [Key Laboratory of Coal Science and Technology of Shanxi Province and Ministry of Education, Taiyuan University of Technology, Taiyuan (China); Feng, G. [Shanghai Research Institute of Petrochemical Technology SINOPEC, Shanghai (China); Han, L. [Key Laboratory of Coal Science and Technology of Shanxi Province and Ministry of Education, Taiyuan University of Technology, Taiyuan (China); College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan (China)

    2012-09-15

    Cerium oxide-doped ZnFe{sub 2}O{sub 4} sorbents supported on modified semi-coke (MSC) were prepared to improve the desulfurization efficiency of zinc ferrites. The sulfidation tests of the ZnFe{sub 2}O{sub 4}/MSC sorbents with and without Ce were carried out using a fixed-bed reactor at 450 C. The effect of the CeO{sub 2}/ZnFe{sub 2}O{sub 4} molar ratio of the sorbents on the sulfur capacity was studied. The characteristics of the sorbents were analyzed by X-ray diffraction, N{sub 2} adsorption, scanning electron microscopy and X-ray photoelectron spectroscopy. The results showed that cerium oxide could greatly improve the desulfurization reactivity of the ZnFe{sub 2}O{sub 4}/MSC sorbents. The molar ratio of Ce to Zn and Fe influences the desulfurization reactivity, and a good sulfur capacity of the sorbent can be obtained with a Ce/Zn/Fe ratio of 4:4:1. It was also found that the addition of CeO{sub 2} could enlarge the surface area and the pore volume, thus improving the dispersion of active components. Ce doping results in an increment of the oxygen adsorbed on the sorbent surface, which facilitates the adsorption of H{sub 2}S. The Ce ions could act as carriers of the oxidation and reduction reactions and the oxygen transfer could be accelerated during the desulfurization process of coal gas. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Cerium and jojoba in engines?; Cerium et jojoba dans les moteurs?

    Energy Technology Data Exchange (ETDEWEB)

    Massy-Delhotel, E.

    1996-10-01

    The Belgium company CreaTel proposes a new system, called Forac, which can lead to a 10% reduction of fuel consumption in thermal engines together with a quasi-complete reduction of CO, HC, NOx pollutants and CO{sub 2} particulates emission. The system comprises a steam production device and an admission pipe with a cerium alloy whorl inside. The steam produced is mixed with the admission air and tears cerium particles from the inside of the admission pipe to the combustion chamber. The cerium particles act as a catalyst which favours the complete combustion of the fuel. The same company proposes also lubricant additives made from liquid jojoba wax which allow the reduction of pollutant emissions, fuel consumption and noise emissions of diesel engines. (J.S.)

  14. Impact of organic carbon and nutrients mobilized during chemical oxidation on subsequent bioremediation of a diesel-contaminated soil

    NARCIS (Netherlands)

    Sutton, N.B.; Grotenhuis, J.T.C.; Rijnaarts, H.H.M.

    2014-01-01

    Remediation with in situ chemical oxidation (ISCO) impacts soil organic matter (SOM) and the microbial community, with deleterious effects on the latter being a major hurdle to coupling ISCO with in situ bioremediation (ISB). We investigate treatment of a diesel-contaminated soil with Fenton’s reage

  15. Impact of organic carbon and nutrients mobilized during chemical oxidation on subsequent bioremediation of a diesel-contaminated soil

    NARCIS (Netherlands)

    Sutton, N.B.; Grotenhuis, J.T.C.; Rijnaarts, H.H.M.

    2014-01-01

    Remediation with in situ chemical oxidation (ISCO) impacts soil organic matter (SOM) and the microbial community, with deleterious effects on the latter being a major hurdle to coupling ISCO with in situ bioremediation (ISB). We investigate treatment of a diesel-contaminated soil with Fenton’s

  16. Reduction of low temperature engine pollutants by understanding the exhaust species interactions in a diesel oxidation catalyst.

    Science.gov (United States)

    Lefort, I; Herreros, J M; Tsolakis, A

    2014-02-18

    The interactions between exhaust gas species and their effect (promotion or inhibition) on the light-off and activity of a diesel oxidation catalyst (DOC) for the removal of pollutants are studied, using actual engine exhaust gases from the combustion of diesel, alternative fuels (rapeseed methyl ester and gas-to-liquid fuel) and diesel/propane dual fuel combustion. The activity of the catalyst was recorded during a heating temperature ramp where carbon monoxide (CO) and hydrocarbon (HC) light-off curves were obtained. From the catalyst activity tests, it was found that the presence of species including CO, medium-heavy HC, alkenes, alkanes, and NOx and their concentration influence the catalyst ability to reduce CO and total HC emissions before release to the atmosphere. CO could inhibit itself and other species oxidation (e.g., light and medium-heavy hydrocarbons) while suffering from competitive adsorption with NO. Hydrocarbon species were also found to inhibit their own oxidation as well as CO through adsorption competition. On the other hand, NO2 was found to promote low temperature HC oxidation through its partial reduction, forming NO. The understanding of these exhaust species interactions within the DOC could aid the design of an efficient aftertreatment system for the removal of diesel exhaust pollutants.

  17. CHEMICAL BEHAVIOR OF CERIUM ELEMENT IN ROCK WEATHERING SYSTEM

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    A study on existing valence state and chemical behavior of cerium element in two categories of rock weathering system in China has been carried out. In the granitoid weathering crust of Southern China,cerium as tetravalent hydroxide absorbed on clay minerals occupies 62.58 % of total amount of cerium and the cerium partitioning in the phase is 69.58 %. The depositing cerium stops its mobility downward, resulting in rare earth partitioning variation, the light rare earth partitioning is high at upper layer of weathering crust, the heavy rare earth partitioning is high at bottom layer of weathering crust, and the extracted product exists cerium lose effect. For Mn2+ as reducing agent existing in black weathering earth of Maoniuping rare earth ore,cerium is trivalent and absorbed on Mn-Fe oxide as colloid phase sediment. Colloid sediment phase can be divided into Mn-Fe combined phase and hydroxide sediment phase with cerium contents of 19.77% and 48.30%, and their cerium partitionings are 80.72% and 37.38% respectively. The Mn-Fe combined phase can selectively absorb cerium.

  18. Effects of Aftermarket Control Technologies on Gas and Particle Phase Oxidative Potential from Diesel Engine Emissions

    Science.gov (United States)

    Particulate matter (PM) originating from diesel combustion is a public health concern due to its association with adverse effects on respiratory and cardiovascular diseases and lung cancer. This study investigated emissions from three stationary diesel engines (gensets) with var...

  19. Determining the Source of Water Vapor in a Cerium Oxide Electrochemical Oxygen Separator to Achieve Aviator Grade Oxygen

    Science.gov (United States)

    Graf, John; Taylor, Dale; Martinez, James

    2014-01-01

    More than a metric ton of water is transported to the International Space Station (ISS) each year to provide breathing oxygen for the astronauts. Water is a safe and compact form of stored oxygen. The water is electrolyzed on ISS and ambient pressure oxygen is delivered to the cabin. A much smaller amount of oxygen is used each year in spacesuits to conduct Extra Vehicular Activities (EVAs). Space suits need high pressure (>1000 psia) high purity oxygen (must meet Aviator Breathing Oxygen "ABO" specifications, >99.5% O2). The water / water electrolysis system cannot directly provide high pressure, high purity oxygen, so oxygen for EVAs is transported to ISS in high pressure gas tanks. The tanks are relatively large and heavy, and the majority of the system launch weight is for the tanks and not the oxygen. Extracting high purity oxygen from cabin air and mechanically compressing the oxygen might enable on-board production of EVA grade oxygen using the existing water / water electrolysis system. This capability might also benefit human spaceflight missions, where oxygen for EVAs could be stored in the form of water, and converted into high pressure oxygen on-demand. Cerium oxide solid electrolyte-based ion transport membranes have been shown to separate oxygen from air, and a supported monolithic wafer form of the CeO2 electrolyte membrane has been shown to deliver oxygen at pressures greater than 300 psia. These supported monolithic wafers can withstand high pressure differentials even though the membrane is very thin, because the ion transport membrane is supported on both sides (Fig 1). The monolithic supported wafers have six distinct layers, each with matched coefficients of thermal expansion. The wafers are assembled into a cell stack which allows easy air flow across the wafers, uniform current distribution, and uniform current density (Fig 2). The oxygen separation is reported to be "infinitely selective" to oxygen [1] with reported purity of 99.99% [2

  20. 铁铈复合氧化物催化剂SCR脱硝的改性研究%Study on the modification of iron-cerium mixed oxide catalyst for selective catalytic reduction of NO

    Institute of Scientific and Technical Information of China (English)

    熊志波; 路春美

    2013-01-01

    利用共沉淀法制备了铁铈催化剂,考察添加钛、锆、钨和钼对其SCR脱硝的改性规律.结果表明,钨和钼的添加提高了铁铈催化剂高温脱硝性能,却使其低温活性有所降低;钛的添加对铁铈催化剂脱硝性能具有促进作用,尤其提高了其低温活性,并拓宽了其完全转化温度窗口,为最佳改性物.当钛的物质的量比逐渐由0.10增至0.40,铁铈钛催化剂低温脱硝效率先增大后减小,但其高温脱硝效率逐渐增大至100%,钛的最佳物质的量比为0.15.XRD和N2吸附分析结果表明,钛能优化铁铈催化剂的孔隙结构,增大其比表面积和比孔容,细化其孔径,并与催化剂中铁、铈氧化物形成良好的固溶体,从而提高了铁铈催化剂的SCR脱硝性能.Fe0.8Ce0.05Ti0.15Oz催化剂在150 ~400℃取得了高于90%的NOx转化率.%A series of iron-cerium mixed oxide catalysts modified titanium, zirconium, tungsten and molybdenum were prepared by co-precipitation. The selective catalytic reduction of NOx with NH3(NH3-SCR) activity of the catalysts were carried out in a fixed-bed quartz tube reactor. The research results indicated that the addition of tungsten and molybdenum could increase the high-temperature NH3-SCR activity of the iron-cerium mixed oxide catalysts, but decreased its low-temperature NH3-SCR activity. Titanium could improve the NH3-SCR activity of the iron-cerium mixed oxide catalyst within the range of reaction temperature, especially at low-temperature. Titanium was the most suitable assistant. When increasing the molar fraction of titanium from 0.10 to 0.40, the low-temperature NH3-SCR activity of iron-cerium-titanium mixed oxide catalysts firstly increased and then decreased while the high-temperature activity gradually increased to 100% , and the optimum molar fraction of titanium was 0.15. The results of X-ray diffraction(XRD) and N2 adsorption isotherms showed that the addition of titanium could optimize the pore

  1. Stability of Commercial Small-Sized Cerium Oxide in the Presence of Biological Material: Dilucidating Relationships between Reactivity and Toxicity of Nanomaterials

    Science.gov (United States)

    Cervini-Silva, J.; Gilbert, B.; Fernandez-Lomelin, P.; Guzman-Mendoza, J.; Chavira, E.

    2007-05-01

    Cerium is the most abundant lanthanide and generally the only one to undergo redox reactions at the Earth's surface. Although rarely studied in natural environments, the redox chemistry of cerium may regulate metal toxicity. Unlike Ce(III) or other lanthanide ions, Ce(IV) has shown a remarkably efficacy to hydrolyze DNA. While Ce(IV) has been recognized as an important candidate to occupy peptidases catalytic centers, Ce(III) is virtually inactive for peptide hydrolysis. The selectivity of Ce as Ce(IV) relates to the specific coordination of water molecules and their orientation. Ce(IV) may bind selectivity to biomolecules to instigate conformation changes or cleavage of complexes, which affect metabolic pathways pivotal to growth and survival. For instance, Ce(IV) promotes the selective cleavage of RNA-type substrates, cyclic monophosphates, peptides, or monocleotides such as AMP, leading to mixtures of nucleosides and nucleobases. Association constants for Ce(IV)-DNA complexes are reported to be higher in magnitude for single stranded than double stranded DNA, while cleavage rates for either complexes are comparable. Complexation of Ce(IV) with mitoxantrone results in the intercalation of such complex into DNA, enabling mitoxantrone to bind effectively with DNA, along with concomitant conformational changes in the DNA double helix and inhibition of DNA synthesis. To the authors' knowledge, however, little information is available on the reactivity as it relates to toxicity of Ce-bearing nanoparticles widely used in nanotechnological applications. Here, we study molecular interactions between small-sized CeO2 and biomolecules(e.g., DNA, RNA, proteins) using carbon and cerium spectroscopy. Suspension stability as determined by aggregation kinetics was studied by Dynamic Light Scattering (DSL) and UV. In addition, acidophiles and fungi cultures were analyzed by nephelometry to estimate population density and growth rate values. Results show a progressive increase in

  2. Role of tantalum nitride as active top electrode in electroforming-free bipolar resistive switching behavior of cerium oxide-based memory cells

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Muhammad, E-mail: ismailmalikbzu10@gmail.com [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Ahmed, Ejaz; Rana, Anwar Manzoor; Talib, Ijaz; Khan, Tahira [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Iqbal, Khalid [Department of Radiation Oncology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore (Pakistan); Nadeem, Muhammad Younus [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan)

    2015-05-29

    Electroforming-free cerium oxide-based bipolar resistive switching memory devices have been deposited using radio frequency magnetron sputtering technique. These devices demonstrate two types of forming-free cells: some in the low-resistance state and the others in high-resistance state. The transmission electron microscopy and X-ray diffraction analyses illustrate the formation of tantalum oxynitride layer between tantalum nitride (TaN) and cerium oxide (CeO{sub x}), which looks to be responsible for the two types of cells as well as their memory performance. Ohmic and Poole-Frenkel conduction mechanisms are found to be responsible for charge transport in the low- and high-resistance states. The current-voltage characteristics and temperature dependence of resistance suggest that resistive switching mechanism in our TaN/CeO{sub x}/Pt devices may be explained by the model of connection and disconnection of filamentary paths made of oxygen vacancies. The reliability characteristics of TaN/CeO{sub x}/Pt devices indicate better endurance and stable retention performance at relatively lower programming voltages and larger memory window (OFF/ON resistance ratio ~ 10{sup 3}) at room temperature and at 100 °C. - Highlights: • Electroforming-free TaN/CeO{sub x}/Pt memory cells have been fabricated by sputtering. • Device exhibits good endurance, long data retention and high-resistance window (~ 10{sup 3}). • Voltages for SET and RESET transitions of our device exhibit narrow distribution. • The device is forming-free due to pre-existence of abundant oxygen vacancies. • TaN top electrode play major role in uniformity of resistive switching characteristics.

  3. Study of the cerium(IV)-picrate system in acetonitrile.

    Science.gov (United States)

    Kratochvil, B; Tipler, M; McKay, B

    1966-07-01

    A potentiometric and spectrophotometric study has been made of the reaction between hexanitratocerate and picrate in dry acetonitrile. Several cerium(IV)-picrate complexes are formed; the formation constant for the first is estimated to be 4 from spectrophotometric measurements. The catalytic effect of picrate on hydroquinone oxidation by nitratocerate is postulated to be due to more rapid electron transfer by cerium picrate complexes.

  4. Effect of cerium additives on structure and electrical properties of Aurivillius oxides (K{sub 0.16}Na{sub 0.84}){sub 0.5}Bi{sub 4.5}Ti{sub 4}O{sub 15}

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Pinyang, E-mail: fpy_2000@163.com [Shaanxi key Laboratory of Photoelectric Functional Materials and Devices, School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710032 (China); College of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062 (China); Liu, Peng, E-mail: liupeng@snnu.edu.cn [College of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062 (China); Xi, Zengzhe; Long, Wei; Li, Xiaojuan [Shaanxi key Laboratory of Photoelectric Functional Materials and Devices, School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710032 (China)

    2014-08-01

    Highlights: • Cerium modified KNBT ceramics were synthesized using the solid-state process. • The d{sub 33} and ρ of KNBT ceramic were improved by cerium additives. • The tan δ at high temperature of KNBT ceramic was suppressed by cerium additive. • The d{sub 33} and T{sub c} of KNBT-Ce50 ceramic were 28 pC/N and 656 °C, respectively. - Abstract: The effect of cerium additive on structure and electric properties of Aurivillius oxide (K{sub 0.16}Na{sub 0.84}){sub 0.5}Bi{sub 4.5}Ti{sub 4}O{sub 15} (KNBT), was investigated. Phase analysis was performed by X-ray diffraction analyses (XRD) and Raman spectroscopy. Morphologies were assessed by the scanning electron microscopy. Piezoelectric properties of the KNBT ceramic were improved by the modification of cerium ions. Dielectric loss at high temperature of the KNBT ceramic was also suppressed because of the cerium ions introduced. Piezoelectric coefficient (d{sub 33}) and Curie temperature (T{sub c}) of KNBT ceramic modified with 0.50 wt% cerium were 28 pC/N and 656 °C, respectively, together with higher resistivity (higher than 10{sup 7} Ω cm at 550 °C). Moreover, reasons for the improvement of electric properties of the KNBT ceramic modified by cerium were also discussed.

  5. Cerium anomaly at microscale in fossils.

    Science.gov (United States)

    Gueriau, Pierre; Mocuta, Cristian; Bertrand, Loïc

    2015-09-01

    Patterns in rare earth element (REE) concentrations are essential instruments to assess geochemical processes in Earth and environmental sciences. Excursions in the "cerium anomaly" are widely used to inform on past redox conditions in sediments. This proxy resources to the specificity of cerium to adopt both the +III and +IV oxidation states, while most rare earths are purely trivalent and share very similar reactivity and transport properties. In practical terms, the level of cerium anomaly is established through elemental point quantification and profiling. All these models rely on a supposed homogeneity of the cerium oxidation state within the samples. However, this has never been demonstrated, whereas the cerium concentration can significantly vary within a sample, as shown for fossils, which would vastly complicate interpretation of REE patterns. Here, we report direct micrometric mapping of Ce speciation through synchrotron X-ray absorption spectroscopy and production of local rare earth patterns in paleontological fossil tissues through X-ray fluorescence mapping. The sensitivity of the approach is demonstrated on well-preserved fishes and crustaceans from the Late Cretaceous (ca. 95 million years (Myr) old). The presence of Ce under the +IV form within the fossil tissues is attributed to slightly oxidative local conditions of burial and agrees well with the limited negative cerium anomaly observed in REE patterns. The [Ce(IV)]/[Ce(tot)] ratio appears remarkably stable at the microscale within each fossil and is similar between fossils from the locality. Speciation maps were obtained from an original combination of synchrotron microbeam X-ray fluorescence, absorption spectroscopy, and diffraction, together with light and electron microscopy. This work also highlights the need for more systematic studies of cerium geochemistry at the microscale in paleontological contexts, in particular across fossil histologies.

  6. In Situ Raman Spectroscopic of Cerium Surface Oxidation and Reduction Processes%金属铈表面氧化还原过程的原位拉曼光谱研究

    Institute of Scientific and Technical Information of China (English)

    吕俊波; 郭淑兰; 李赣

    2013-01-01

    The surface oxidation and reduction processes of cerium were monitored by in situ microscope Raman spectroscopy.A peak at 462 cm-1 attributed to the characteristic vibration of CeO2 disappeared and two sharp peaks at 2132 and 2239 cm-1 attributed to the electronic scattering of Ce3+ were observed at high temperature and vacuum conditions.The results indicated that the surface oxide on cerium sample were transformed from CeO2 to Ce2O3.According to the changes of peak intensities at 1503,1796,2100cm-1,also attributed to electronic scattering of Ce3+and the characteristic vibration peak of CeO2,the surface oxidation process of cerium in the air could be divided into three steps.First,all cerium oxide layers with different cerium valence increased quickly.Then,the outer CeO2 layer stopped growing,but those cerium oxide layers contained Ce3+ continued growing.Finally,CeO2 layer increased quickly again with the appearance of OH-at 3603 cm-1%采用显微拉曼光谱仪原位监测了金属铈表面的氧化和还原过程.2132和2239 cm-1处尖锐Ce3+电子散射峰的出现及462 cm-1处CeO2特征振动峰的消失表明,在高温、高真空条件下金属铈表层的CeO2已转变为Ce2O3.根据1503,1796和2113 cm-1处多个Ce3+电子散射峰及CeO2特征振动峰强度随时间的变化关系,可将金属Ce在空气中的氧化过程分为3个阶段,首先不同价态铈氧物层均快速增长,随后外层的CeO2陷入停顿,含Ce3+的铈氧物层继续增长,最后随着3603 cm-1处OH-的出现,CeO2再次快速增长.

  7. Cooling of a Diesel Reformate Fuelled Solid Oxide Fuel Cell by Internal Reforming of Methane: A Modelling Study

    Institute of Scientific and Technical Information of China (English)

    HUANG Xiaowei; Alexander Kromp

    2013-01-01

    In this paper a system combining a diesel reformer using catalytic partial oxidation (CPOX) with the Solid Oxide Fuel Cell (SOFC) for Auxiliary Power Unit (APU) applications is modeled with respect to the cooling effect provided by internal reforming of methane in anode gas channel.A model mixture consisting of 80% n-hexadecane and 20% 1-methylnaphthalin is used to simulate the commercial diesel.The modelling consists of several steps.First,equilibrium gas composition at the exit of CPOX reformer is modelled in terms oxygen to carbon (O/C) ratio,fuel utilization ratio and anode gas recirculation.Second,product composition,especially methane content,is determined for the methanation process at the operating temperatures ranging from 500 ℃ to 520 ℃.Finally,the cooling power provided by internal reforming of methane in SOFC fuel channel is calculated for two concepts to increase the methane content of the diesel reformate.The results show that the first concept,operating the diesel reformer at low O/C ratio and/or recirculation ratio,is not realizable due to high probability of coke formation,whereas the second concept,combining a methanation process with CPOX,can provide a significant cooling effect in addition to the conventional cooling concept which needs higher levels of excess air.

  8. Regression-based oxides of nitrogen predictors for three diesel engine technologies.

    Science.gov (United States)

    Chen, Xiaohan; Schmid, Natalia A; Wang, Lijuan; Clark, Nigel N

    2010-01-01

    Models of diesel engine emissions such as oxides of nitrogen (NO(x)) are valuable when they can predict instantaneous values because they can be incorporated into whole vehicle models, support inventory predictions, and assist in developing superior engine and aftertreatment control strategies. Recent model-year diesel engines using multiple injection strategies, exhaust gas recirculation, and variable geometry turbocharging may have more transient sensitivity and demand more sophisticated modeling than for legacy engines. Emissions data from 1992, 1999, and 2004 model-year U.S. truck engines were modeled separately using a linear approach (with transient terms) and multivariate adaptive regression splines (MARS), an adaptive piece-wise regression approach that has limited prior use for emissions prediction. Six input variables based on torque, speed, power, and their derivatives were used for MARS. Emissions time delay was considered for both models. Manifold air temperature (MAT) and manifold air pressure (MAP) were further used in NO(x) modeling to build a plug-in model. The predictive performance for instantaneous NO(x) on part of the certification transient test procedure (Federal Test Procedure [FTP]) of the 2004 engine MARS was lower (R2 = 0.949) than the performance for the 1992 (R2 = 0.981) and 1999 (R2 = 0.988) engines. Linear regression performed similarly for the 1992 and 1999 engines but performed poorly (R2 = 0.896) for the 2004 engine. The MARS performance varied substantially when data from different cycles were used. Overall, the MAP and MAT plug-in model trained by MARS was the best, but the performance differences between LR and MARS were not substantial.

  9. Modeling Species Inhibition of NO Oxidation in Urea-SCR Catalysts for Diesel Engine NOx Control

    Energy Technology Data Exchange (ETDEWEB)

    Devarakonda, Maruthi N.; Tonkyn, Russell G.; Tran, Diana N.; Lee, Jong H.; Herling, Darrell R.

    2011-04-20

    Urea-selective catalytic reduction (SCR) catalysts are regarded as the leading NOx aftertreatment technology to meet the 2010 NOx emission standards for on-highway vehicles running on heavy-duty diesel engines. However, issues such as low NOx conversion at low temperature conditions still exist due to various factors, including incomplete urea thermolysis, inhibition of SCR reactions by hydrocarbons and H2O. We have observed a noticeable reduction in the standard SCR reaction efficiency at low temperature with increasing water content. We observed a similar effect when hydrocarbons are present in the stream. This effect is absent under fast SCR conditions where NO ~ NO2 in the feed gas. As a first step in understanding the effects of such inhibition on SCR reaction steps, kinetic models that predict the inhibition behavior of H2O and hydrocarbons on NO oxidation are presented in the paper. A one-dimensional SCR model was developed based on conservation of species equations and was coded as a C-language S-function and implemented in Matlab/Simulink environment. NO oxidation and NO2 dissociation kinetics were defined as a function of the respective adsorbate’s storage in the Fe-zeolite SCR catalyst. The corresponding kinetic models were then validated on temperature ramp tests that showed good match with the test data. Such inhibition models will improve the accuracy of model based control design for integrated DPF-SCR aftertreatment systems.

  10. MnO{sub x}-CeO{sub 2} For The Low-Temperature Oxidation Of Diesel Soot

    Energy Technology Data Exchange (ETDEWEB)

    Tikhomirov, K.; Kroecher, O.; Elsener, M.; Wokaun, A.

    2005-03-01

    MnO{sub x}-CeO{sub 2} was found to be a highly active catalyst for the low-temperature oxidation of Diesel soot. The catalytic activity could be traced to the storage of nitrates on the catalyst surface at low temperatures followed by the release of NO{sub 2} when heated over 280 C. The poor sulphur resistance of the catalyst poses the main problem for its practical application. (author)

  11. Formation and characterization of cerium conversion coatings on magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    LI Lingjie; LEI Jinglei; YU Shenghai; TIAN Yujing; JIANG Qiquan; PAN Fusheng

    2008-01-01

    Chemical conversion treatment by rare earth metal salt solution was considered as an alternative to chromium chemical conversion treatment to improve the corrosion resistance of magnesium alloys. In this study, cerium conversion coatings formed on AZ31 magnesium alloy were characterized and the formation mechanism was discussed. X-ray photoelectron spectroscopy (XPS) analysis showed that cerium conversion coating consisted of cerium hydroxides/oxides, in which both tetravalent cerium Ce(IV) and trivalent cerium Ce(III) species co-existed. Cerium conversion coating was a two-layer structure. Atomic force microscopy (AFM) images revealed that the morphology of the inside layer was different from that of the outside one, which was responsible for the inherent adhesive weakness of the coating. Corrosion potential (Ecorr) measurements indicated that poor adhesion limited the improvement of the corrosion resistance of the coating. During the treating process, the increased pH value of the cerium salt solution led to the precipitation of cerium hydroxides/oxides. The formation kinetics of the coating followed a parabolic curve.

  12. Effects of cerium dioxide nanoparticles in Oncorhynchus mykiss liver after an acute exposure: assessment of oxidative stress, genotoxicity and histological alterations

    Directory of Open Access Journals (Sweden)

    Ana Cristina Nunes

    2015-12-01

    Full Text Available At present cerium oxide nanoparticles (CeO2 NP have numerous applications ranging from industry to the household, leading to its wide distribution namely in the aquatic environment. The hereby study aimed to assess the toxic effects of CeO2 NPs in Oncorhynchus mykiss liver following an acute exposure (96h to three different concentrations (0.25, 2.5 and 25 mg/L in terms of the genotoxicity (comet assay, oxidative stress response (Catalase CAT; Glutathione S-Transferases GSTs; Thiobarbituric Acid Reactive Substances TBARS and histopathology. CeO2 NP exposure resulted in genotoxic damage in all exposure treatments, inhibition of CAT in the highest concentration and histopathological changes in all exposure concentrations with predominance of progressive and circulatory alterations. However TBARS and GSTs showed no significant differences comparatively to the control (unexposed group. The results suggest that CeO2 NP are able to cause genotoxicity, biochemical impairment and histological alterations in the liver of rainbow trout.

  13. Impact of organic carbon and nutrients mobilized during chemical oxidation on subsequent bioremediation of a diesel-contaminated soil.

    Science.gov (United States)

    Sutton, Nora B; Grotenhuis, Tim; Rijnaarts, Huub H M

    2014-02-01

    Remediation with in situ chemical oxidation (ISCO) impacts soil organic matter (SOM) and the microbial community, with deleterious effects on the latter being a major hurdle to coupling ISCO with in situ bioremediation (ISB). We investigate treatment of a diesel-contaminated soil with Fenton's reagent and modified Fenton's reagent coupled with a subsequent bioremediation phase of 187d, both with and without nutrient amendment. Chemical oxidation mobilized SOM into the liquid phase, producing dissolved organic carbon (DOC) concentrations 8-16 times higher than the untreated field sample. Higher aqueous concentrations of nitrogen and phosphorous species were also observed following oxidation; NH4(+) increased 14-172 times. During the bioremediation phase, dissolved carbon and nutrient species were utilized for microbial growth-yielding DOC concentrations similar to field sample levels within 56d of incubation. In the absence of nutrient amendment, the highest microbial respiration rates were correlated with higher availability of nitrogen and phosphorus species mobilized by oxidation. Significant diesel degradation was only observed following nutrient amendment, implying that nutrients mobilized by chemical oxidation can increase microbial activity but are insufficient for bioremediation. While all bioremediation occurred in the first 28d of incubation in the biotic control microcosm with nutrient amendment, biodegradation continued throughout 187d of incubation following chemical oxidation, suggesting that chemical treatment also affects the desorption of organic contaminants from SOM. Overall, results indicate that biodegradation of DOC, as an alternative substrate to diesel, and biological utilization of mobilized nutrients have implications for the success of coupled ISCO and ISB treatments.

  14. Cerium oxide nanoparticles alter the antioxidant capacity but do not impact tuber ionome in Raphanus sativus (L).

    Science.gov (United States)

    Corral-Diaz, Baltazar; Peralta-Videa, Jose R; Alvarez-Parrilla, Emilio; Rodrigo-García, Joaquin; Morales, Maria Isabel; Osuna-Avila, Pedro; Niu, Genhua; Hernandez-Viezcas, Jose A; Gardea-Torresdey, Jorge L

    2014-11-01

    The effects of nCeO2 on food quality are not well known yet. This research was performed to determine the impact of nCeO2 on radish (Raphanus sativus L.). Plants were cultivated to full maturity in potting soil treated with nCeO2 at concentrations of 0, 62.5, 125, 250, and 500 mg/kg. Germination, growth, photosynthesis, ionome, and antioxidants were evaluated at different growth stages. Results showed that at 500 mg/kg, nCeO2 significantly retarded seed germination but did not reduce the number of germinated seeds. None of the treatments affected gas exchange, photosynthesis, growth, phenols, flavonoids, and nutrients' accumulation in tubers and leaves of adult plants. However, tubers' antioxidant capacity, expressed as FRAP, ABTS(•-) and DPPH, increased by 30%, 32%, and 85%, respectively, in plants treated with 250 mg nCeO2kg(-1) soil. In addition, cerium accumulation in tubers of plants treated with 250 and 500 mg/kg reached 72 and 142 mg/kg d wt, respectively. This suggests that nCeO2 could improve the radical scavenging potency of radish but it might introduce nCeO2 into the food chain with unknown consequences.

  15. Effect of metal oxides on the reactivity of persulfate/Fe(II) in the remediation of diesel-contaminated soil and sand.

    Science.gov (United States)

    Do, Si-Hyun; Kwon, Yong-Jae; Kong, Sung-Ho

    2010-10-15

    The effect of metal oxides on the ability of persulfate (PS) with Fe(II) to remediate diesel-contaminated soil was investigated. In both natural soil and purchased sand, the highest diesel degradation occurred at pH 3 and the optimum molar ratio of PS/Fe(II) was 100:1 (i.e. 500 mM PS to 5 mM Fe(II)). Moreover, adding Fe(II) increased PS reactivity more in soil than it did in sand, indicating the involvement of metal oxides in the soil matrix. Evaluating the effects of metal oxides (i.e. goethite, hematite, magnetite, and manganese oxide) on the reactivity of PS with/without Fe(II) in a system containing diesel-contaminated sand revealed that manganese oxide increased PS activity the most and that the highest diesel degradation by PS occurred when both manganese oxide and Fe(II) were used as activators. XRD did not show the transformation of manganese oxide in the presence of Fe(II). SEM-EDS showed the association of Fe(II) on the surface of manganese oxide, and ICP analysis revealed that almost all the added Fe(II) adsorbed to manganese oxide but almost none adsorbed to iron oxides under acidic conditions. Therefore, the high reactivity of PS could be due to the high density of Fe(II) over the surface of manganese oxide. 2010 Elsevier B.V. All rights reserved.

  16. Role of compost, bentonite and calcium oxide in restricting the effect of soil contamination with petrol and diesel oil on plants.

    Science.gov (United States)

    Wyszkowski, Mirosław; Ziólkowska, Agnieszka

    2009-02-01

    The studies have been initiated to find a way to use compost, bentonite and calcium oxide in order to reduce the effect of contaminated soil with a small amount of petrol or diesel oil on the yield and nitrogen content in crop plants--spring rape and oats cultivated as the main and aftercrop. Petrol and diesel oil had a toxic effect on the growth of the plants and modified nitrogen content, with the intensity of the effect depending upon their type and dose and on the type of applied substance reducing the effect of oil derivatives. Spring rape (main crop), was more sensitive, and oats (aftercrop) was less so. Petroleum-derived substances reduced the yield of spring rape by a maximum of 73% for petrol and by as much as 99% for diesel oil. Nitrogen content was higher for spring rape than for oats and larger for petrol than for diesel oil. Adding bentonite, calcium oxide or compost to the soil contaminated with oil derivatives usually reduced the negative effect of petrol and diesel oil on plant growth and reduced the protein nitrogen content and increased the total nitrogen content in plants. Bentonite proved to be the most effective, with calcium oxide and compost slightly less so. The most positive results were obtained for spring rape as the main crop. An addition of compost, bentonite and calcium oxide to soil had a stronger modifying effect on nitrogen content in plants on soils contaminated by diesel oil than petrol.

  17. 电化学阻抗谱法研究铈改性TiO2纳米管阵列光电极裂解水产氢动力学%Dynamics Study on the Cerium and Oxidative Cerium Modified TiO2 Nanotube Arrays for Hydrogen Production by Water Splitting Using Electrochemical Impedance Spectrum

    Institute of Scientific and Technical Information of China (English)

    张胜寒; 梁可心; 檀玉

    2012-01-01

    TiO2 nanotube arrays photoelectrodes were prepared by anode oxidation on pure Ti sheet. The donor material glycol (C2H6O2) added in the anode electrolyte significantly reduced the charge transfer impedance of TiO2 nanotubes to promote the photocatalytic water splitting for hydrogen production. TiO2 nanotube arrays electrodes were modified by cerium and oxidative cerium with electrochemical deposition and anodic oxidation. The fiat band potential moves to the negative potential direction after modification. Electrochemical impedance spectrum (EIS) measurement was used to investigate the electron transfer characteristic in photoelectrodes and the interface characteristic in the photoelectrochemical cell (PEC) for hydrogen production. Arcs of EIS and corresponding electrode processes were discussed. Dynamic parameters of the electrodes were calculated by reasonable electrical equivalent circuit fitting. The results indicate that TiO2 nanotube arrays electrode modified by cerium and oxidative cerium could largely decrease the electron transfer resistance which contributes to hydrogen production. The mechanism of the cerium and oxidative cerium acting on TiO2 nanotube arrays to promote charge transfer is discussed.%通过阳极氧化法在纯钛板上制备TiO2纳米管阵列电极.在光电化学电解池阳极中加入供电子物质乙二醇,显著减小了TiO2纳米管的电荷传递阻抗,促进了光电催化裂解水产氢反应.采用阴极电沉积和阳极氧化法制备了单质铈和氧化铈共同改性的TiO2纳米管阵列半导体光阳极,其平带电位向电负方向移动.采用电化学阻抗谱法(EIS)对改性后TiO2纳米管阵列在光电催化裂解水产氢中的电子传输性能以及界面性质进行了表征,确定了各阻抗弧对应的电极过程.采用合理的等效电路模型计算了电极的电子传输动力学参数.结果表明,经铈改性后的TiO2纳米管阵列膜电阻明显减小,

  18. Kinetic studies on dissolution of UO{sub 2} powders in acid solutions by using cerium (IV) or chlorine dioxide as oxidants

    Energy Technology Data Exchange (ETDEWEB)

    Asano, Yuichiro; Kataoka, Makoto; Tomiyasu, Hiroshi [Tokyo Inst. of Tech. (Japan). Research Lab. for Nuclear Reactors; Ikeda, Yasuhisa

    1996-02-01

    The UO{sub 2} powders of 100-150, 150-212, 212-250, and 250-300 {mu}m were dissolved in HNO{sub 3} or HCl solutions containing strong oxidants to examine their effect on the dissolution rates. Cerium(IV) species and ClO{sub 2} were used as oxidants in HNO{sub 3} and HCl solutions, respectively. The Ce(IV) species were prepared by bubbling O{sub 3} gas into HNO{sub 3} solutions containing Ce(NO{sub 3}){sub 3}. All dissolution experiments were carried out under rapid stirring conditions which make it possible to neglect the diffusion effect. Dissolution reactions were analyzed on the assumptions that the UO{sub 2} powders are spherical particles and homogeneously dissolved from their external surface. Dissolution rate constants ({Phi}) in mol{center_dot}cm{sup -2}{center_dot}min{sup -1} were measured at various concentrations of oxidants and temperatures. Furthermore, the effect of acid concentrations on the dissolution rate was also examined. As a result, the dissolution rate constants {Phi} were found to be expressed as {Phi}=k{sub N}[Ce(IV)][H{sup +}]{sup 0.6} for HNO{sub 3} solution([HNO{sub 3}]=1-5M, Temp.{<=}30degC) and {Phi}=k{sub H}[ClO{sub 2}][H{sup +}]{sup -0.3} for HCl solution([HCl]=1-5M, Temp.{<=}30degC), respectively. Activation energies(kJ{center_dot}mol{sup -1}) for the apparent dissolution rate constants are 44.1{+-}1.9 for the HNO{sub 3} solution system and 33.5{+-}2.8 for the HCl solution system, respectively. (author).

  19. Engineering aspects and hardware verification of a volume producable solid oxide fuel cell stack design for diesel auxiliary power units

    Science.gov (United States)

    Stelter, Michael; Reinert, Andreas; Mai, Björn Erik; Kuznecov, Mihail

    A solid oxide fuel cell (SOFC) stack module is presented that is designed for operation on diesel reformate in an auxiliary power unit (APU). The stack was designed using a top-down approach, based on a specification of an APU system that is installed on board of vehicles. The stack design is planar, modular and scalable with stamped sheet metal interconnectors. It features thin membrane electrode assemblies (MEAs), such as electrolyte supported cells (ESC) and operates at elevated temperatures around 800 °C. The stack has a low pressure drop in both the anode and the cathode to facilitate a simple system layout. An overview of the technical targets met so far is given. A stack power density of 0.2 kW l -1 has been demonstrated in a fully integrated, thermally self-sustaining APU prototype running with diesel and without an external water supply.

  20. Study of oil diesel degradation in soil using oxidative advanced processes; Estudo da degradacao do oleo diesel em solo utilizando processos oxidativos avancados

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Suenia S.; Silva, Valdinete L. da; Motta, Mauricio da [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Engenharia Quimica; Silva, Paula Tereza de S. e; Barros Neto, Benicio de [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Quimica Fundamental

    2004-07-01

    Recently it comes if observing several accidents during the exploration, refinement, transport and operation of storage of petroleum and yours derived, such as the diesel oil and the gasoline. In this paper We do a study of the degradation of the diesel oil in a characteristic soil of the state of Pernambuco using peroxide of hydrogen and Fenton reagent. Those two processes are based on the generation of the radical hydroxyl (OH.) that has to can oxidizer loud capable to promote the destruction of recalcitrant organic compositions. The studied soil has about 16,5{+-}0,3 g/kg of total organic carbon. A factorial planning was accomplished 2{sup 3} with 2 repetitions in the central point with the objective of finding the best conditions of degradation of the pollutant. The variables and the studied levels were: FeSO{sub 4} - 0,18 M (0, 4 and 8 Ml); pH (3; without adjustment and without adjustment) and Time of exhibition in the sun (8; 12 and 16:00). The volumes of H{sub 2}O{sub 2} used in the rehearsals were constant, being 80 mL. Soon afterwards it accomplished a fractional experimental planning 2{sup 3-1}, repeating the variables of the first planning, they put using a smaller volume of H{sub 2}O{sub 2}, 40 mL, to evaluate the influence of the amount of H{sub 2}O{sub 2} used about the degradation of the diesel oil. The mass of the soil used in each experiment was of 5 g. It was observed that there were not significant differences in the degradation in relation to the peroxide volume. The best found degradation was around 87% in the following conditions (4 mL of Faith, without pH adjustment, Time of exhibition in the sun of 12:00 and 80 ml of H{sub 2}O{sub 2}). That found degradation was quite satisfactory being still due to study more economical conditions. (author)

  1. [application of the analytical transmission electron microscopy techniques for detection, identification and visualization of localization of nanoparticles of titanium and cerium oxides in mammalian cells].

    Science.gov (United States)

    Shebanova, A S; Bogdanov, A G; Ismagulova, T T; Feofanov, A V; Semenyuk, P I; Muronets, V I; Erokhina, M V; Onishchenko, G E; Kirpichnikov, M P; Shaitan, K V

    2014-01-01

    This work represents the results of the study on applicability of the modern methods of analytical transmission electron microscopy for detection, identification and visualization of localization of nanoparticles of titanium and cerium oxides in A549 cell, human lung adenocarcinoma cell line. A comparative analysis of images of the nanoparticles in the cells obtained in the bright field mode of transmission electron microscopy, under dark-field scanning transmission electron microscopy and high-angle annular dark field scanning transmission electron was performed. For identification of nanoparticles in the cells the analytical techniques, energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy, were compared when used in the mode of obtaining energy spectrum from different particles and element mapping. It was shown that the method for electron tomography is applicable to confirm that nanoparticles are localized in the sample but not coated by contamination. The possibilities and fields of utilizing different techniques for analytical transmission electron microscopy for detection, visualization and identification of nanoparticles in the biological samples are discussed.

  2. An oxidative desulfurization method using ultrasound/Fenton's reagent for obtaining low and/or ultra-low sulfur diesel fuel

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Yongchuan; Qi, Yutai [Department of Applied Chemistry, School of Science, Harbin Institute of Technology, Harbin 115001 (China); Zhao, Dezhi [Department of Petroleum Chemical Engineering, Liaoning Shihua University, Fushun 113001 (China); Zhang, Huicheng [Fushun Research Institute of Petroleum and Petrochemicals of SINOPEC Corp., Fushun 113001 (China)

    2008-10-15

    The total development trend in the world is towards continuously lower of sulfur content as a quality standard of diesel fuels. Integrating of an oxidative desulfurization unit with a conventional hydrotreating unit can bring benefits to producing low and/or ultra-low sulfur diesel fuels. Using the hydrotreated Middle East diesel fuel as a feedstock, four processes of the oxidative desulfurization have been studied: a hydrogen peroxide-acetic acid system and a Fenton's reagent system both without/with ultrasound. Results showed that the oxidative desulfurization reaction mechanics fitted apparent first-order kinetics. The addition of Fenton's reagent could enhance the oxidative desulfurization efficiency for diesel fuels and sono-oxidation treatment in combination with Fenton's reagent shows a good synergistic effect. Under our best operating condition for the oxidative desulfurization: temperature 313 K, ultrasonic power 200 W, ultrasonic frequency 28 kHz, Fe{sup 2+}/H{sub 2}O{sub 2} 0.05 mol/mol, pH 2.10 in aqueous phase and reaction time 15 min, the sulfur content in the diesel fuels was decreased from 568.75 {mu}g/g to 9.50 {mu}g/g. (author)

  3. Importance of Vanadium-Catalyzed Oxidation of SO2to SO3in Two-Stroke Marine Diesel Engines

    DEFF Research Database (Denmark)

    Colom, Juan M.; Alzueta, María U.; Christensen, Jakob Munkholt

    2016-01-01

    Low-speed marine diesel engines are mostly operated on heavy fuel oils, which have a high content of sulfur andash, including trace amounts of vanadium, nickel, and aluminum. In particular, vanadium oxides could catalyze in-cylinderoxidation of SO2 to SO3, promoting the formation of sulfuric acid...... of the catalyticspecies within the engine. Experiments with different particle compositions (vanadium/sodium ratio) and temperatures (300−800 °C) show that both the temperature and sodium content have a major impact on the oxidation rate. Kinetic parameters forthe catalyzed reaction are determined, and the proposed...... kinetic model fits well with the experimental data. The impact of thecatalytic reaction is studied with a phenomenological zero-dimensional (0D) engine model, where fuel oxidation and SOxformation is modeled with a comprehensive gas-phase reaction mechanism. Results indicate that the oxidation of SO2...

  4. Oxidative stability of waste cooking oil and white diesel upon storage at room temperature.

    Science.gov (United States)

    Bezergianni, Stella; Chrysikou, Loukia P

    2012-12-01

    Renewable diesel fuels are alternative fuels produced from vegetable oils or animal fats. Catalytic hydrotreating of waste cooking oil (WCO) was carried out at pilot-plant scale and a paraffinic diesel, called "white" diesel was obtained. The white diesel and WCO samples were stored for one year at room temperature under normal atmospheric conditions, but not exposed to sunlight. Viscosity, total acid number (TAN), induction period (IP), carbonaceous deposits, density, cold flow properties, distillation and water content were monitored. TAN and density of the white diesel stored in conventional bottles changed from 0 to 0.221 mg KOH/g and from 787 to 838 kg/m(3), respectively. The remaining parameters did not vary significantly. Water content of WCO increased from 482 to 2491 mg/kg, TAN from 0.744 to 0.931 mg KOH/g, whereas viscosity, IP and carbon residues fluctuated mildly. The results are indicative of the white diesel's stability, rendering it suitable for prolonged storage.

  5. Isothermal Kinetics of Diesel Soot Oxidation over La0.7K0.3ZnOy Catalysts

    Directory of Open Access Journals (Sweden)

    Ram Prasad

    2014-10-01

    Full Text Available This paper describes the kinetics of catalytic oxidation of diesel soot with air under isothermal conditions (320-350 oC. Isothermal kinetics data were collected in a mini-semi-batch reactor. Experiments were performed over the best selected catalyst composition La0.7K0.3ZnOy prepared by sol-gel method. Characterization of the catalyst by XRD and FTIR confirmed that La1-xKxZnOy did not exhibit perovskite phase but formed mixed metal oxides. 110 mg of the catalyst-soot mixture in tight contact (10:1 ratio was taken in order to determine the kinetic model, activation energy and Arrhenius constant of the oxidation reaction under the high air flow rate assuming pseudo first order reaction. The activation energy and Arrhenius constant were found to be 138 kJ/mol and 6.46x1010 min-1, respectively. © 2014 BCREC UNDIP. All rights reservedReceived: 26th April 2014; Revised: 27th May 2014; Accepted: 28th June 2014How to Cite: Prasad, R., Kumar, A., Mishra, A. (2014. Isothermal Kinetics of Diesel Soot Oxidation over La0.7K0.3ZnOy Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 9(3: 192-200. (doi: 10.9767/bcrec.9.3.6773.192-200Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.3.6773.192-200

  6. Mixed cerium-platinum oxides: Electronic structure of [CeO]Ptn (n = 1, 2) and [CeO2]Pt complex anions and neutrals

    Science.gov (United States)

    Ray, Manisha; Kafader, Jared O.; Topolski, Josey E.; Jarrold, Caroline Chick

    2016-07-01

    The electronic structures of several small Ce-Pt oxide complexes were explored using a combination of anion photoelectron (PE) spectroscopy and density functional theory calculations. Pt and Pt2 both accept electron density from CeO diatomic molecules, in which the cerium atom is in a lower-than-bulk oxidation state (+2 versus bulk +4). Neutral [CeO]Pt and [CeO]Pt2 complexes are therefore ionic, with electronic structures described qualitatively as [CeO+2]Pt-2 and [CeO+]Pt2-, respectively. The associated anions are described qualitatively as [CeO+]Pt-2 and [CeO+]Pt2-2, respectively. In both neutrals and anions, the most stable molecular structures determined by calculations feature a distinct CeO moiety, with the positively charged Ce center pointing toward the electron rich Pt or Pt2 moiety. Spectral simulations based on calculated spectroscopic parameters are in fair agreement with the spectra, validating the computationally determined structures. In contrast, when Pt is coupled with CeO2, which has no Ce-localized electrons that can readily be donated to Pt, the anion is described as [CeO2]Pt-. The molecular structure predicted computationally suggests that it is governed by charge-dipole interactions. The neutral [CeO2]Pt complex lacks charge-dipole stabilizing interactions, and is predicted to be structurally very different from the anion, featuring a single Pt-O-Ce bridge bond. The PE spectra of several of the complexes exhibit evidence of photodissociation with Pt- daughter ion formation. The electronic structures of these complexes are related to local interactions in Pt-ceria catalyst-support systems.

  7. Probing the cerium/cerium hydride interface using nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Brierley, Martin, E-mail: martin.brierley@awe.co.uk [Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR (United Kingdom); University of Manchester, Manchester M13 9PL (United Kingdom); Knowles, John, E-mail: john.knowles@awe.co.uk [Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR (United Kingdom)

    2015-10-05

    Highlights: • A disparity exists between the minimum energy and actual shape of a cerium hydride. • Cerium hydride is found to be harder than cerium metal by a ratio of 1.7:1. • A zone of material under compressive stress was identified surrounding the hydride. • No distribution of hardness was apparent within the hydride. - Abstract: A cerium hydride site was sectioned and the mechanical properties of the exposed phases (cerium metal, cerium hydride, oxidised cerium hydride) were measured using nanoindentation. An interfacial region under compressive stress was observed in the cerium metal surrounding a surface hydride that formed as a consequence of strain energy generated by the volume expansion associated with precipitation of the hydride phase.

  8. Effect of cerium addition on oxidation behavior of 2SCr20Ni alloy under lowoxygen partial pressure

    Institute of Scientific and Technical Information of China (English)

    SHAO Mingzeng; CUI Lishan; ZHENG Yanjun; XING Linlin

    2012-01-01

    The influence of Ce addition on the oxidation behavior of 25Cr20Ni alloy at 950 ℃ under low oxygen partial pressure was investigated.The oxidized samples were characterized by using X-ray diffraction (XRD),scanning electron microscopy (SEM),energy dispersive X-ray spectroscopy (EDS),and scratch tester to obtain the oxide phases,morphology,thickness,composition and adhesion property of the oxide scales.The experiment results indicated that a small amount of Ce addition (0.02 wt.% or 0.05 wt.%) promoted oxidation resistance and inhibited the growth of the needlelike oxide.The Ce addition also decreased the formation of MnCr2O4 but promoted the SiO2 formation underneath the Cr2O3,which largely contributed to the improvement of oxide scale spallation resistance.For the sample with 0.3 wt.% Ce addition,the oxidation rate significantly increased and the spallation resistance of the oxide scale decreased.

  9. Mixed-phase oxide catalyst based on Mn-mullite (Sm, Gd)Mn2O5 for NO oxidation in diesel exhaust.

    Science.gov (United States)

    Wang, Weichao; McCool, Geoffrey; Kapur, Neeti; Yuan, Guang; Shan, Bin; Nguyen, Matt; Graham, Uschi M; Davis, Burtron H; Jacobs, Gary; Cho, Kyeongjae; Hao, Xianghong

    2012-08-17

    Oxidation of nitric oxide (NO) for subsequent efficient reduction in selective catalytic reduction or lean NO(x) trap devices continues to be a challenge in diesel engines because of the low efficiency and high cost of the currently used platinum (Pt)-based catalysts. We show that mixed-phase oxide materials based on Mn-mullite (Sm, Gd)Mn(2)O(5) are an efficient substitute for the current commercial Pt-based catalysts. Under laboratory-simulated diesel exhaust conditions, this mixed-phase oxide material was superior to Pt in terms of cost, thermal durability, and catalytic activity for NO oxidation. This oxide material is active at temperatures as low as 120°C with conversion maxima of ~45% higher than that achieved with Pt. Density functional theory and diffuse reflectance infrared Fourier transform spectroscopy provide insights into the NO-to-NO(2) reaction mechanism on catalytically active Mn-Mn sites via the intermediate nitrate species.

  10. Influence of fuel properties, nitrogen oxides, and exhaust treatment by an oxidation catalytic converter on the mutagenicity of diesel engine emissions

    Energy Technology Data Exchange (ETDEWEB)

    Buenger, Juergen; Bruening, Thomas [Ruhr University Bochum, Research Institute for Occupational Medicine of the Institutions for Statutory Accident Insurance and Prevention (BGFA), Bochum (Germany); Krahl, Juergen; Schroeder, Olaf [Federal Agricultural Research Centre, Institute of Biosystems Engineering, Braunschweig (Germany); Weigel, Andreas; Mueller, Michael; Hallier, Ernst; Westphal, Goetz [University of Goettingen, Department of Occupational and Social Medicine, Gottingen (Germany)

    2006-08-15

    Particle emissions of diesel engines (DEP) content polycyclic aromatic hydrocarbons (PAH) these compounds cause a strong mutagenicity of solvent extracts of DEP. We investigated the influence of fuel properties, nitrogen oxides (NO{sub x}), and an oxidation catalytic converter (OCC) on the mutagenic effects of DEP. The engine was fuelled with common diesel fuel (DF), low-sulphur diesel fuel (LSDF), rapeseed oil methyl ester (RME), and soybean oil methyl ester (SME) and run at five different load modes in two series with and without installation of an OCC in the exhaust pipe. Particles from the cooled and diluted exhaust were sampled onto glass fibre filters and extracted with dichloromethane in a soxhlet apparatus. The mutagenicity of the extracts was tested using the Salmonella typhimurium/mammalian microsome assay with tester strains TA98 and TA100. Without OCC the number of revertant colonies was lower in extracts of LSDF than in extracts of DF. The lowest numbers of revertant colonies were induced by the plant oil derived fuels. In three load modes, operation with the OCC led to a reduction of the mutagenicity. However, direct mutagenic effects under heavy duty conditions (load mode A) were significantly increased for RME (TA98, TA100) and SME (TA98). A consistent but not significant increase in direct mutagenicity was observed for DF and LSDF at load mode A, and for DF at idling (load mode E) when emissions were treated with the OCC. These results raise concern over the use of oxidation catalytic converters with diesel engines. We hypothesise that the OCC increases formation of direct acting mutagens under certain conditions by the reaction of NO{sub x} with PAH resulting in the formation of nitrated-PAH. Most of these compounds are powerful direct acting mutagens. (orig.)

  11. Oxidative DNA damage in vitamin C-supplemented guinea pigs after intratracheal instillation of diesel exhaust particles

    DEFF Research Database (Denmark)

    Moller, P.; Daneshvar, B.; Loft, S.

    2003-01-01

    of oxidized amino acids (gamma-glutamyl semialdehyde), DNA strand breaks, and 7-hydro-8-oxo-2'-deoxyguanosine (8-oxodG) in the lung. Bulky DNA ad- ducts were not significantly elevated in the lung. The antioxidant enzyme activity of glutathione reductase was increased in the lung of DEP-exposed guinea pigs......The health effects of diesel exhaust particles (DEP) are thought to involve oxidative damage. We have investigated the effect of intratracheal DEP instillation to guinea pigs in three groups of 12 animals each given 0, 0.7, or 2.1 mg. Five days later guinea pigs exposed to DEP had increased levels......, whereas glutathione peroxidase and superoxide dismutase enzyme activities were unaltered. There was no difference in DNA strand breaks in lymphocytes or urinary excretion of 8-oxodG at the two doses tested. Protein oxidations in plasma and in erythrocytes were not altered by DEP exposure...

  12. DNA adduct formation and oxidative stress in colon and liver of Big Blue rats after dietary exposure to diesel particles

    DEFF Research Database (Denmark)

    Dybdahl, Marianne; Risom, Lotte; Møller, Peter

    2003-01-01

    Exposure to diesel exhaust particles (DEP) via the gastrointestinal route may impose risk of cancer in the colon and liver. We investigated the effects of DEP given in the diet to Big Blue rats by quantifying a panel of markers of DNA damage and repair, mutation, oxidative damage to proteins...... and lipids, and antioxidative defence mechanisms in colon mucosa cells, liver tissue and the blood compartment. Seven groups of rats were fed a diet with 0, 0.2, 0.8, 2, 8, 20 or 80 mg DEP/kg feed for 21 days. DEP induced a significant increase in DNA strand breaks in colon and liver. There was no effect...... of ERCC1 gene was affected in liver, but not in colon. In addition to these effects, DEP exposure induced apoptosis in liver. There was no significant change in mutation frequency in colon or liver. The levels of oxidative protein modifications (oxidized arginine and proline residues) were increased...

  13. Oxidative DNA damage in vitamin C-supplemented guinea pigs after intratracheal instillation of diesel exhaust particles

    DEFF Research Database (Denmark)

    Moller, P.; Daneshvar, B.; Loft, S.

    2003-01-01

    The health effects of diesel exhaust particles (DEP) are thought to involve oxidative damage. We have investigated the effect of intratracheal DEP instillation to guinea pigs in three groups of 12 animals each given 0, 0.7, or 2.1 mg. Five days later guinea pigs exposed to DEP had increased level...... for the study of oxidative damage induced by particulate matter. (C) 2003 Elsevier Science (USA). All rights reserved........ The concentrations of ascorbate in liver, lung, and plasma were unaltered by the DEP exposure. The results indicate that in guinea pigs DEP causes oxidative DNA damage rather than bulky DNA adducts in the lung. Guinea pigs, which are similar to humans with respect to vitamin C metabolism, may serve as a new model...

  14. Experimental investigation into effects of addition of zinc oxide on performance, combustion and emission characteristics of diesel-biodiesel-ethanol blends in CI engine

    Directory of Open Access Journals (Sweden)

    B. Prabakaran

    2016-12-01

    Full Text Available This study is to investigate the effect of zinc oxide nano particle addition to diesel-biodiesel-ethanol blends. Solubility tests were done for the fuels at three different temperatures. Out of eighteen blends, six blends were stable at 5 °C, 15 °C and above 25 °C. Out of the six blends, two blends were checked for properties as per ASTM standards. One of them was chosen for testing the performance, combustion and emission characteristics in a diesel engine. In the same blend, zinc oxide was added in the amount of 250 ppm. Property testing of the blended fuel indicated that there was an increase in calorific value due to addition of nano particle. The performance tests were conducted on a single cylinder four stroke direct injection diesel engine at a constant speed of 1500 rpm. For the blend containing zinc oxide, there was an increase in BSFC, HRR and cylinder pressure. Also, there was a decrease in BTE, NOx and smoke, as compared to diesel. The addition of zinc oxide nano particles increased the BTE and decreased the BSFC as compared with the biodiesel diesel ethanol blend at full load. This study gives a direction to utilize the renewable fuel to reduce the consumption of fossil fuel.

  15. Diesel oil

    Science.gov (United States)

    Oil ... Diesel oil ... Diesel oil poisoning can cause symptoms in many parts of the body. EYES, EARS, NOSE, AND THROAT Loss of ... most dangerous effects of hydrocarbon (such as diesel oil) poisoning are due to inhaling the fumes. NERVOUS ...

  16. Cerium sequestration and accumulation in fractured crystalline bedrock: The role of Mn-Fe (hydr-)oxides and clay minerals

    Science.gov (United States)

    Yu, Changxun; Drake, Henrik; Mathurin, Frédéric A.; Åström, Mats E.

    2017-02-01

    This study focuses on the mechanisms of Ce sequestration and accumulation in the fracture network of the upper kilometer of the granitoid bedrock of the Baltic Shield in southeast Sweden (Laxemar area, Sweden). The material includes 81 specimens of bulk secondary mineral precipitates (;fracture coatings;) collected on fracture walls identified in 17 drill cores, and 66 groundwater samples collected from 21 deep boreholes with equipment designed for retrieval of representative groundwater at controlled depths. The concentrations of Ce in the fracture coatings, although varying considerably (10-90th percentiles: 67-438 mg kg-1), were frequently higher than those of the wall rock (10-90th percentiles: 70-118 mg kg-1). Linear combination fitting analysis of Ce LIII-edge X-ray absorption near-edge structure (XANES) spectra, obtained for 19 fracture coatings with relatively high Ce concentrations (⩾145 mg kg-1) and a wide range of Ce-anomaly values, revealed that Ce(IV) occurs frequently in the upper 10 m of the fracture network (Ce(IV)/Cetotal = 0.06-1.00 in 8 out of 11 specimens) and is mainly associated with Mn oxides (modeled as Ce oxidatively scavenged by birnessite). These features are in line with the strong oxidative and sorptive capacities of Mn oxide as demonstrated by previous studies, and abundant todorokite and birnessite-like Mn oxides identified in 3 out of 4 specimens analyzed by Mn K-edge X-ray absorption spectroscopy (XAS) in the upper parts of the fracture network (down to 5 m). For a specimen with very high Ce concentration (1430 mg kg-1) and NASC-normalized Ce anomaly (3.63), the analysis of Ce XANES and Mn XAS data revealed (i) a predominance of Ce oxide in addition to Ce scavenged by Mn oxide; and (ii) a large fraction of poorly-crystalline hexagonal birnessite and aqueous Mn2+, suggesting a recent or on-going oxidation of Mn2+ in this fracture. In addition, the Ce oxide precipitates on this fracture observed by in situ SEM-EDS contained

  17. Humic Substances-dependent Aggregation and Transport of Cerium Oxide Nanoparticles in Porous Media at Different pHs and Ionic Strengths

    Science.gov (United States)

    Mu, L.; Jacobson, A. R.; Darnault, C. J. G.

    2015-12-01

    Cerium oxide nanoparticles (CeO2 NPs) are commonly used in several fields and industries, such as chemical and pharmaceutical, due to both their physical and chemical properties. For example, they are employed in the manufacturing of catalysts, as fuel additives, and as polishing agents. The release and exposure to CeO2 NPs can occur during their fabrication, application, and waste disposal, as well as through their life-cycle and accidents. Therefore, the assessment of the dynamic nature of CeO2 NPs stability and mobilty in the environment is of paramount importance to establish the environmental and public health risks associated with their inevitable release in the environment. Humic substances are a key element of soils and have been revealed to possibly affect the fate and transport of nanoparticles in soils. Consequently, our present research aims at investigating the influence that different pHs, monovalent and divalent cations, Suwannee River humic acid, and Suwanee River fulvic acid have on the aggregation, transport, and deposition of CeO2 NPs. Batch studies performed with different concentrations of humic and fulvic acids associated with a wide spectrum of pHs and ionic strengths were examined. Key variables from these batch studies were then examined to simulate experimental conditions commonly encountered in the soil-water system to conduct column transport experiments in order to establish the fate and transport of CeO2 NPs in saturated porous media, which is a critical phase in characterizing the behavior of CeO2 NPs in subsurface environmental systems.

  18. Thermochemical reactivity of 5–15 mol% Fe, Co, Ni, Mn-doped cerium oxides in two-step water-splitting cycle for solar hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Gokon, Nobuyuki, E-mail: ngokon@eng.niigata-u.ac.jp [Center for Transdisciplinary Research, Niigata University, 8050 Ikarashi 2-nocho, Nishi-ku, Niigata 950-2181 (Japan); Suda, Toshinori [Graduate School of Science and Technology, Niigata University, 8050 Ikarashi 2-nocho, Niigata 950-2181 (Japan); Kodama, Tatsuya [Department of Chemistry & Chemical Engineering, Faculty of Engineering, Niigata University, 8050 Ikarashi 2-nocho, Niigata 950-2181 (Japan)

    2015-10-10

    Highlights: • 5–15 mol% M-doped ceria are examined for thermochemical two-step water-splitting. • 5 mol% Fe- and Co-doped ceria have stoichiometric production of oxygen and hydrogen. • 10–15 mol% Fe- and Mn-doped ceria showed near-stoichiometric production. - Abstract: The thermochemical two-step water-splitting cycle using transition element-doped cerium oxide (M–CeO{sub 2−δ}; M = Fe, Co, Ni, Mn) powders was studied for hydrogen production from water. The oxygen/hydrogen productivity and repeatability of M–CeO{sub 2−δ} materials with M doping contents in the 5–15 mol% range were examined using a thermal reduction (TR) temperature of 1500 °C and water decomposition (WD) temperatures in the 800–1150 °C range. The temperature, steam partial pressure, and steam flow rate in the WD step had an impact on the hydrogen productivity and production rate. 5 mol% Fe- and Co-doped CeO{sub 2−δ} enhances hydrogen productivity by up to 25% on average compared to undoped CeO{sub 2}, and shows stable repeatability of stoichiometric oxygen and hydrogen production for the cyclic thermochemical two-step water-splitting reaction. In addition, 5 mol% Mn-doped CeO{sub 2−δ}, 10 and 15 mol% Fe- and Mn-doped CeO{sub 2−δ} show near stoichiometric reactivities.

  19. Tuning Reactivity and Electronic Properties through Ligand Reorganization within a Cerium Heterobimetallic Framework

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Jerome R.; Gordon, Zachary; Booth, Corwin H.; Carroll, Patrick J.; Walsh, Patrick J.; Schelter, Eric J.

    2014-06-24

    Cerium compounds have played vital roles in organic, inorganic, and materials chemistry due to their reversible redox chemistry between trivalent and tetravalent oxidation states. However, attempts to rationally access molecular cerium complexes in both oxidation states have been frustrated by unpredictable reactivity in cerium(III) oxidation chemistry. Such oxidation reactions are limited by steric saturation at the metal ion, which can result in high energy activation barriers for electron transfer. An alternative approach has been realized using a rare earth/alkali metal/1,1'-BINOLate (REMB) heterobimetallic framework, which uses redox-inactive metals within the secondary coordination sphere to control ligand reorganization. The rational syntheses of functionalized cerium(IV) products and a mechanistic examination of the role of ligand reorganization in cerium(III) oxidation are presented.

  20. Pharmacological potential of cerium oxidenanoparticles

    Science.gov (United States)

    Celardo, Ivana; Pedersen, Jens Z.; Traversa, Enrico; Ghibelli, Lina

    2011-04-01

    Nanotechnology promises a revolution in pharmacology to improve or create ex novo therapies. Cerium oxidenanoparticles (nanoceria), well-known as catalysts, possess an astonishing pharmacological potential due to their antioxidant properties, deriving from a fraction of Ce3+ ions present in CeO2. These defects, compensated by oxygen vacancies, are enriched at the surface and therefore in nanosized particles. Reactions involving redox cycles between the Ce3+ and Ce4+oxidation states allow nanoceria to react catalytically with superoxide and hydrogen peroxide, mimicking the behavior of two key antioxidant enzymes, superoxide dismutase and catalase, potentially abating all noxious intracellularreactive oxygen species (ROS) via a self-regenerating mechanism. Hence nanoceria, apparently well tolerated by the organism, might fight chronic inflammation and the pathologies associated with oxidative stress, which include cancer and neurodegeneration. Here we review the biological effects of nanoceria as they emerge from in vitro and in vivo studies, considering biocompatibility and the peculiar antioxidant mechanisms.

  1. The oxidation of water by cerium(IV) catalysed by nanoparticulate RuO2 on mesoporous silica.

    Science.gov (United States)

    King, Nicola C; Dickinson, Calum; Zhou, Wuzong; Bruce, Duncan W

    2005-03-21

    Mesoporous silicates are prepared by templating on the hexagonal (H1) mesophase of surfactant bipyridine complexes of ruthenium(II) using a true liquid-crystal templating approach. On calcination, the surfactant template is removed except for the central metal ion that is oxidised, forming nanoparticles of RuO2 that deposit within the pores. RuO2 is a known oxidation catalyst and, despite its anhydrous nature in these silicates, is found to be very active in catalyzing the oxidation of water by acidic CeIV.

  2. 直馏柴油催化氧化脱硫均相催化剂的制备与评价%Preparation and evaluation of desulfurization catalysts for homogeneous catalytic oxidation of straight-run diesel

    Institute of Scientific and Technical Information of China (English)

    唐晓东; 刘亮; 税蕾蕾

    2005-01-01

    Large investment, high operating cost and severe operation condition exist in the technology of diesel hydrodesulfurization, and the technology of H2O2 oxidative desulfurization of diesel has such problems as high oxidizer cost, oxidizer not regenerable, and treatment of sour water. A new catalytic oxidative desulfurization method for straight-run diesel is presented in this paper. In order to produce lowsulfur diesel, the sulfide in diesel oil was oxidized and converted into sulfone-polar sulfide with homogeneous catalysts and air oxidizer, and then removed by extractant. The homogenous catalysts were prepared by compound decomposition. The catalysts selected could dissolve in diesel at a given temperature and separate out at a lower temperature. The effects of catalytic oxidation of zinc benzoate, manganese benzoate and manganese phthalate were tested. The desulfurization effect of zinc benzoate and manganese benzoate was much better and the sulfur content of the desulfurized diesel met the standard of Eu Ⅱ diesel (<300μg·g-1 ).

  3. Preparation and application of cerium-based composite nano oxides%铈基纳米复合氧化物的研究及其应用进展

    Institute of Scientific and Technical Information of China (English)

    闫玉玲; 李丽华; 张金生; 吴限

    2016-01-01

    综述了以氧化铈为基的纳米复合氧化物的国内外研究进展,阐述了纳米TiO2-CeO2、CeO2-ZnO、ZrO2/CeO2及CeO2与其他氧化物的复合(如Al2 O3、CaO、CuO等)材料的制备与性能,最后对铈基纳米复合材料的研究进行了展望。%Review of the present research status of cerium-based composite nano oxides .The preparation and application of TiO2-CeO2,CeO2-ZnO,ZrO2/CeO2 and other complex oxides (such as CeO2/Al2 O3, CeO2/CaO,CeO2/CuO) are reviewed.Prospects on both research and application of cerium-based com-posite nano oxides are proposed in the end .

  4. Cerium neodymium oxide solid solution synthesis as a potential analogue for substoichiometric AmO2 for radioisotope power systems

    Science.gov (United States)

    Watkinson, E. J.; Ambrosi, R. M.; Williams, H. R.; Sarsfield, M. J.; Stephenson, K.; Weston, D. P.; Marsh, N.; Haidon, C.

    2017-04-01

    The European Space Agency (ESA) is sponsoring a research programme on the development of americium oxides for radioisotope generators and heater units. Cubic AmO2-(x/2) with an O/Am ratio between 1.65 and 1.75 is a potentially suitable compound for pellet sintering. C-type (Ia-3) Ce1-xNdxO2-(x/2) oxides with 0.5 < x < 0.7 could be used as a surrogate for some Ia-3 AmO2-(x/2). A new Ce1-xNdxO2-(x/2) production process has been investigated where a nominally selected x value of 0.6 was targeted: Ce and Nd nitrates and oxalic acid were added drop-wise into a vessel, where they continuously reacted to create oxalate precipitates. The effect of temperature (25 °C, 60 °C) of the reactants (mixed at 250 revolutions per minute) on oxalate particle shape and size were investigated. Oxalates were calcined at 900 °C to produce oxide particles. Oxalate particle properties were characterised as these are expected to influence oxides particle properties and fuel pellet sintering.

  5. The Involvement of Superoxide and Nitric Oxide in Inflammation-Enhanced Diesel Exhaust Particle Cytotoxicity

    Science.gov (United States)

    Thirty-four million Americans have asthma, a chronic inflammatory lung disease. Although the mechanisms are unclear, epidemiologic studies show that exposure of asthmatics to air pollutants, like diesel exhaust particles (DEP), is more likely to result in adverse health effects....

  6. A cerium oxide nanoparticle-based device for the detection of chronic inflammation via optical and magnetic resonance imaging

    Science.gov (United States)

    Kaittanis, Charalambos; Santra, Santimukul; Asati, Atul; Perez, J. Manuel

    2012-03-01

    Monitoring of microenvironmental parameters is critical in healthcare and disease management. Harnessing the antioxidant activity of nanoceria and the imaging capabilities of iron oxide nanoparticles in a device setup, we were able to image changes in the device's aqueous milieu. The device was able to convey and process changes in the microenvironment's pH and reactive oxygen species' concentration, distinguishing physiological from abnormal levels. As a result under physiological and transient inflammatory conditions, the device's fluorescence and magnetic resonance signals, emanating from multimodal iron oxide nanoparticles, were similar. However, under chronic inflammatory conditions that are usually associated with high local concentrations of reactive oxygen species and pH decrease, the device's output was considerably different. Specifically, the device's fluorescence emission significantly decreased, while the magnetic resonance signal T2 increased. Further studies identified that the changes in the device's output are attributed to inactivation of the sensing component's nanoceria that prevents it from successfully scavenging the generated free radicals. Interestingly, the buildup of free radical excess led to polymerization of the iron oxide nanoparticle's coating, with concomitant formation of micron size aggregates. Our studies indicate that a nanoceria-based device can be utilized for the monitoring of pro-inflammatory biomarkers, having important applications in the management of numerous ailments while eliminating nanoparticle toxicity issues.Monitoring of microenvironmental parameters is critical in healthcare and disease management. Harnessing the antioxidant activity of nanoceria and the imaging capabilities of iron oxide nanoparticles in a device setup, we were able to image changes in the device's aqueous milieu. The device was able to convey and process changes in the microenvironment's pH and reactive oxygen species' concentration

  7. Evolving mass spectra of the oxidized component of organic aerosol: results from aerosol mass spectrometer analyses of aged diesel emissions

    Directory of Open Access Journals (Sweden)

    A. M. Sage

    2007-07-01

    Full Text Available The species and chemistry responsible for secondary organic aerosol (SOA formation remain highly uncertain. Laboratory studies of the oxidation of individual, high-flux SOA precursors do not lead to particles with mass spectra (MS matching those of ambient aged organic material. And, the complexity of real organic particles challenges efforts to identify their chemical origins. We have previously hypothesized that SOA can form from the atmospheric oxidation of a large suite of precursors with varying vapor pressures. Here, we support this hypothesis by using an aerosol mass spectrometer to track the chemical evolution of diesel exhaust as it is photochemically oxidized in an environmental chamber. With explicit knowledge of the condensed-phase MS of the primary emissions from our engine, we are able to decompose each recorded MS into contributing primary and secondary spectra throughout the experiment. We find that the SOA MS becomes increasingly oxidized as a function of time, eventually reaching a final MS that closely resembles that of ambient aged organic particulate matter. This observation is consistent with the idea that lower vapor pressure, semi-volatile organic emissions can form condensable products with fewer generations of oxidation, and therefore, they form relatively less oxidized SOA very quickly.

  8. Redox Reactivity of Cerium Oxide Nanoparticles Induces the Formation of Disulfide Bridges in Thiol-Containing Biomolecules.

    Science.gov (United States)

    Rollin-Genetet, Françoise; Seidel, Caroline; Artells, Ester; Auffan, Mélanie; Thiéry, Alain; Vidaud, Claude

    2015-12-21

    The redox state of disulfide bonds is implicated in many redox control systems, such as the cysteine-cystine couple. Among proteins, ubiquitous cysteine-rich metallothioneins possess thiolate metal binding groups susceptible to metal exchange in detoxification processes. CeO2 NPs are commonly used in various industrial applications due to their redox properties. These redox properties that enable dual oxidation states (Ce(IV)/Ce(III)) to exist at their surface may act as oxidants for biomolecules. The interaction among metallothioneins, cysteine, and CeO2 NPs was investigated through various biophysical approaches to shed light on the potential effects of the Ce(4+)/Ce(3+) redox system on the thiol groups of these biomolecules. The possible reaction mechanisms include the formation of a disulfide bridge/Ce(III) complex resulting from the interaction between Ce(IV) and the thiol groups, leading to metal unloading from the MTs, depending on their metal content and cluster type. The formation of stable Ce(3+) disulfide complexes has been demonstrated via their fluorescence properties. This work provides the first evidence of thiol concentration-dependent catalytic oxidation mechanisms between pristine CeO2 NPs and thiol-containing biomolecules.

  9. Synthesis of praseodymium doped cerium oxides by the polymerization-combustion method for application as anodic component in SOFC devices

    Science.gov (United States)

    Cruz Pacheco, A. F.; Gómez Cuaspud, J. A.; López, E. Vera

    2016-02-01

    This work reports the synthesis and the characterization of six oxides; it is based on Ce1-xPrxO2 (x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) system, which is obtained by the polymerization- combustion technique for potential applications on design of advanced electrodic components, for solid oxide fuel cells (SOFC). Initially the solid precursors are characterized by infrared spectroscopy (FTIR) and thermal analysis (TGA-DTA), allowing to determine the formation of prevalent citrate species and the optimal temperature for the consolidation of the desired crystalline phases. The X-ray diffraction (XRD) and the transmission electron microscopy analysis (TEM) are performed over calcined samples which provided information about the formation of a fluorite phase with grain distribution, surface, textural and morphological properties consistent with the nanometric obtaining crystallites (30nm), it is oriented along the (1 1 1) facet, with d spacings of 0.31nm for the main diffraction signal. These results indicate the effectiveness of the proposed synthesis method for potential applications in the design of advanced anodic materials for solid oxide fuel cells.

  10. Protective Effects of Cerium Oxide Nanoparticles on MC3T3-E1 Osteoblastic Cells Exposed to X-Ray Irradiation

    Directory of Open Access Journals (Sweden)

    Cuifen Wang

    2016-04-01

    Full Text Available Background/Aims: Exposure to ionizing radiation can result in bone damage, including decreased osteocyte number and suppressed osteoblastic activity. However, molecular mechanisms remain to be elucidated, and effective prevention strategies are still limited. This study was to investigate whether cerium oxide nanoparticles (CeO2 NP can protect MC3T3-E1 osteoblast-like cells from damaging effects of X-ray irradiation, and to study the underpinning mechanism(s. Methods: MC3T3-E1, a osteoblast-like cell line, was exposed to X-ray irradiation and treated with different concentration of CeO2 nanoparticles. The micronucleus frequency was counted under a fluorescence microscope. Cell viability was evaluated using MTT assay. The effects of irradiation and CeO2 nanoparticles on alkaline phosphatase activity and MC3T3-E1 mineralization were further assayed. Results: We found that the ratio of micronuclei to binuclei was dose-dependently increased with X-ray irradiation (from 2 to 6 Gy, but diminished with the increased concentration of CeO2 NP treatment (from 50 to 100 nM. Exposure to X-rays (6 Gy decreased cell viability, differentiation and the mineralization, but CeO2 NP treatment (100 nM attenuated the deteriorative effects of irradiation. Both intracellular reactive oxygen species (ROS production and extracellular H2O2 concentration were increased after X-ray irradiation, but reduced following CeO2 NP treatment. Similar to irradiation, exposure to H2O2 (10 µM elevated the frequency of micronuclei and diminished cell viability and mineralization, while these changes were ameliorated following CeO2 NP treatment. Conclusions: Taken together, our findings suggest that CeO2 nanoparticles exhibit astonishing protective effects on irradiation-induced osteoradionecrosis in MC3T3-E1 cells, and the protective effects appear to be mediated, at least partially, by reducing oxidative stress.

  11. Improvement in corrosion resistance of magnesium coating with cerium treatment

    Institute of Scientific and Technical Information of China (English)

    Samia Ben Hassen; Latifa Bousselmi; Patricc Bercot; El Mustafa Rezrazi; Ezzeddine Triki

    2009-01-01

    Corrosion protection afforded by a magnesium coating treated in cerium salt solution on steel substrate was investigated using open circuit potential, polarization curves, and electrochemical impedance spectroscopy (EIS) in 0.005 M sodium chloride solution (NaCl). The morphology of the surface was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The cerium treated coating was obtained by immersion in CeCl3 solution. The results showed that the corrosion resistance of the treated magnesium coating was improved. The corrosion potential of the treated coating was found to be nobler than that of the untreated magnesium coating and the corrosion current decreased significantly. Impedance results showed that the cerium treatment increased corrosion protection. The improvement of anti-corrosion properties was ataibuted to the formation of cerium oxides and hydroxides that gave to a physical barrier effect.

  12. The carbon monoxide oxidation reaction over controlled catalyst structures based on gold/cerium dioxide thin films

    Science.gov (United States)

    Zhou, Zheng

    Gold-based catalysts have attracted significant research interest due to their remarkably high activity for many important reactions, including the low-temperature CO oxidation reaction. Despite extensive studies, several fundamental issues in the understanding of CO oxidation over supported gold catalysts are unresolved. The locus and nature of active sites, including the role of the metal, metal oxide support, and their interface, remain controversial. The objectives of this thesis were to study CO oxidation on Au/CeO2 catalysts that were prepared using thin film techniques so as to form geometrically controlled structures in contrast to the typical supported nanoparticle systems. Using these structures enables one to evaluate the contribution of metal oxide support (CeO2), and locate and identify the active sites in the Au/CeO2 system. In particular, the specific contribution to the reaction by the metal/oxide interface, the role and nature of the vacancies in the oxide, the role of the dimensions of the Au and ceria, and the role of stress in the gold films have been investigated. Two catalyst systems, each employing nanoscale films, were investigated. One was formed from a "single layer" of metal or oxide in the form of an extended surface that was then decorated with a thin layer of the other catalyst partner; the second approach was a study of multilayer metal/oxide structures to assess the role of the metal/metal oxide interface. More specifically the reaction sites formed at the three-phase boundary of metal, metal oxide and gas. In the first case, a Au film (4.5nm) was prepared using vapor deposition on SiO2/Si (100) substrates. The gold coalesced into discrete islands with large lateral size (20-100nm) and was found to be only weakly active. The extremely low activity of gold with large lateral extended surface has been attributed to the lack of uncoordinated gold atoms on this type of gold surface. Subsequently decorating the gold with nanosized ceria

  13. Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

    Science.gov (United States)

    Caputo, Fanny; de Nicola, Milena; Sienkiewicz, Andrzej; Giovanetti, Anna; Bejarano, Ignacio; Licoccia, Silvia; Traversa, Enrico; Ghibelli, Lina

    2015-09-01

    Efficient inorganic UV shields, mostly based on refracting TiO2 particles, have dramatically changed the sun exposure habits. Unfortunately, health concerns have emerged from the pro-oxidant photocatalytic effect of UV-irradiated TiO2, which mediates toxic effects on cells. Therefore, improvements in cosmetic solar shield technology are a strong priority. CeO2 nanoparticles are not only UV refractors but also potent biological antioxidants due to the surface 3+/4+ valency switch, which confers anti-inflammatory, anti-ageing and therapeutic properties. Herein, UV irradiation protocols were set up, allowing selective study of the extra-shielding effects of CeO2vs. TiO2 nanoparticles on reporter cells. TiO2 irradiated with UV (especially UVA) exerted strong photocatalytic effects, superimposing their pro-oxidant, cell-damaging and mutagenic action when induced by UV, thereby worsening the UV toxicity. On the contrary, irradiated CeO2 nanoparticles, via their Ce3+/Ce4+ redox couple, exerted impressive protection on UV-treated cells, by buffering oxidation, preserving viability and proliferation, reducing DNA damage and accelerating repair; strikingly, they almost eliminated mutagenesis, thus acting as an important tool to prevent skin cancer. Interestingly, CeO2 nanoparticles also protect cells from the damage induced by irradiated TiO2, suggesting that these two particles may also complement their effects in solar lotions. CeO2 nanoparticles, which intrinsically couple UV shielding with biological and genetic protection, appear to be ideal candidates for next-generation sun shields.

  14. Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

    KAUST Repository

    Caputo, Fanny

    2015-08-20

    Efficient inorganic UV shields, mostly based on refracting TiO2 particles, have dramatically changed the sun exposure habits. Unfortunately, health concerns have emerged from the pro-oxidant photocatalytic effect of UV-irradiated TiO2, which mediates toxic effects on cells. Therefore, improvements in cosmetic solar shield technology are a strong priority. CeO2 nanoparticles are not only UV refractors but also potent biological antioxidants due to the surface 3+/4+ valency switch, which confers anti-inflammatory, anti-ageing and therapeutic properties. Herein, UV irradiation protocols were set up, allowing selective study of the extra-shielding effects of CeO2vs. TiO2 nanoparticles on reporter cells. TiO2 irradiated with UV (especially UVA) exerted strong photocatalytic effects, superimposing their pro-oxidant, cell-damaging and mutagenic action when induced by UV, thereby worsening the UV toxicity. On the contrary, irradiated CeO2 nanoparticles, via their Ce3+/Ce4+ redox couple, exerted impressive protection on UV-treated cells, by buffering oxidation, preserving viability and proliferation, reducing DNA damage and accelerating repair; strikingly, they almost eliminated mutagenesis, thus acting as an important tool to prevent skin cancer. Interestingly, CeO2 nanoparticles also protect cells from the damage induced by irradiated TiO2, suggesting that these two particles may also complement their effects in solar lotions. CeO2 nanoparticles, which intrinsically couple UV shielding with biological and genetic protection, appear to be ideal candidates for next-generation sun shields. © The Royal Society of Chemistry 2015.

  15. A study of a ceria-zirconia-supported manganese oxide catalyst for combustion of Diesel soot particles

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Escribano, V.; Fernandez Lopez, E.; del Hoyo Martinez, C. [Departamento de Quimica Inorganica, Facultad de Ciencias Quimicas, Pa. de la Merced s/n, E-37008 Salamanca (Spain); Gallardo-Amores, J.M. [Lab. Complutense de Altas Presiones, Departamento de Quimica Inorganica I, Universidad Complutense, Ciudad Universitaria, E-28040 Madrid (Spain); Pistarino, C.; Panizza, M.; Resini, C.; Busca, G. [Dipartimento di Ingegneria Chimica e di Processo, Universita di Genova, P.le J.F. Kennedy, Pad. D, I-16129 Genoa (Italy)

    2008-04-15

    A study has been conducted on the structural and morphological characterization of a Ce-Zr mixed oxide-supported Mn oxide as well as on its catalytic activity in the oxidation of particulate matter arising from Diesel engines. X-ray powder diffraction analysis (XRD) and FT-IR and FT-Raman spectroscopy evidence that the support is a fluorite-like ceria-zirconia solid solution, whereas the supported phase corresponds to the manganese oxide denoted as bixbyite ({alpha}-Mn{sub 2}O{sub 3}). Thermal analyses and FT-IR spectra in air at varying temperatures of soot mechanically mixed with the catalyst evidence that the combustion takes place to a total extent in the range 420-720 K, carboxylic species being detected as intermediate compounds. Moreover, the soot oxidation was studied in a flow reactor and was found to be selective to CO{sub 2}, with CO as by-product in the range 420-620 K. The amount of the generated CO decreases significantly with increasing O{sub 2} concentration in the feed. (author)

  16. Reduction of harmful nitrogen oxide emission from low heat rejection diesel engine using carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Thulasi Gopinathan

    2016-01-01

    Full Text Available In this study, lanthanum aluminate is used as thermal barrier coating material for the first time in the internal combustion engine to convert the standard engine into low heat rejection engine. Initially, the biodiesel is prepared from sunflower oil by using trans-esterification process. The piton crown, cylinder head and valves of the engine is coated with lanthanum aluminate for a thickness of around 200 microns. However, the analysis of performance and emission characteristics of a standard diesel is carried out with diesel/biodiesel to compare with the low heat rejection engine. The lanthanum aluminate coated engine fueled with sunflower methyl ester shows better performance and emission. But the emission of NOx founds to be higher in the coated engine. Further, a small quantity of carbon nanotubes is added onto the biodiesel to carry out the experiments. Based on the results, the carbon nanotubes are added with the biodiesel to reduce the emission of NOx.

  17. Effect of Biodiesel on Diesel Engine Nitrogen Oxide and Other Regulated Emissions

    Science.gov (United States)

    2007-12-01

    process of base - catalyzed transesterification at low temperature (150°F), low pressure (20 pounds per sq in [psi]) and with a high conversion...4 LIST OF TABLES Page Table 1. Emission impacts of B20 for Soybean- Based Biodiesel Added to an Average Base ...Camp Pendleton Marine Corps Base for making the arrangements to supply most of the diesel engines tested in this project. Camp Pendleton was able

  18. Pulmonary exposure to particles from diesel exhaust, urban dust or single-walled carbon nanotubes and oxidatively damaged DNA and vascular function in apoE(-/-)mice

    DEFF Research Database (Denmark)

    Vesterdal, Lise K; Jantzen, Kim; Sheykhzade, Majid

    2012-01-01

    Abstract This study compared the oxidative stress level and vasomotor dysfunction after exposure to urban dust, diesel exhaust particles (DEP) or single-walled carbon nanotubes (SWCNT). DEP and SWCNT increased the production of reactive oxygen species (ROS) in cultured endothelial cells and acell...

  19. A novel catalyst of silicon cerium complex oxides for selective catalytic reduction of NO by NH_3

    Institute of Scientific and Technical Information of China (English)

    徐海涛; 沈岳松; 邵成华; 林福文; 祝社民; 丘泰

    2010-01-01

    A series of CeO2/SiO2 and SixCe1-xO2 complex oxides supported on an activated Al2TiO5-TiO2-SiO2 complex phase (ATS) ceramics were prepared by step impregnation and co-impregnation methods, and characterized by N2-BET, XRD, SEM and NH3-TPD techniques. The effects of reaction temperature, CeO2/SiO2 loadings and Si/Ce molar ratio on the granular catalysts for NO selective catalytic reduction with ammonia (NH3-SCR) were studied. Results indicated that both CeO2/SiO2/ATS and CeO2/ATS catalysts showed the same ac...

  20. Visible light activated photocatalytic degradation of tetracycline by a magnetically separable composite photocatalyst: Graphene oxide/magnetite/cerium-doped titania.

    Science.gov (United States)

    Cao, Muhan; Wang, Peifang; Ao, Yanhui; Wang, Chao; Hou, Jun; Qian, Jin

    2016-04-01

    In this study, magnetic graphene oxide-loaded Ce-doped titania (MGO-Ce-TiO2) hybridized composite was prepared by a facile method. The as-prepared samples exhibited good adsorption capacity, high visible-light photoactive and magnetic separability as a novel photocatalyst in the degradation of tetracyclines (TC). The intermediate products and photocatalytic route of TC were proposed based on the analysis results of LC-MS. Moreover, the repeatability of the photoactivity with the use of MGO-Ce-TiO2 was investigated in the multi-round experiments with the assistance of an applied magnetic field. Therefore, the prepared composite photocatalysts were considered as a kind of promising photocatalyst in a suspension reaction system, in which they can offer effectively recovery ability. The effect of MGO content on the photocatalytic performance was also studied, and an optimum content was obtained. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Effect of Doping Cerium in the Support of Catalyst Pd-Co/Cu-Co-Mn Mixed Oxides on the Oxidative Carbonylation of Phenol%掺杂Ce对Pd-Co/Cu-Co-Mn混合氧化物催化体系氧化羰基化法合成碳酸二苯酯

    Institute of Scientific and Technical Information of China (English)

    梁英华; 郭红霞; 陈红萍; 吕敬德; 张波波

    2009-01-01

    Effect of doping cerium in the support on the catalytic activity and side product of the reaction in the oxidative carbonylation of phenol to diphenyl carbonate (DPC) over the catalyst Pd-Co/Cu-Co-Mn mixed oxides was studied. The specific surface areas, crystal phase, valency, and content of the element on the surface of the catalysts were determined, and the products were detected by gas chromatograph/mass spectrometry (GC-MS). It is found that the catalyst without Ce shows higher activity than that with Cc, and the yields of DPC for the two catalysts can reach 30% and 23%, respectively. However, doping cerium can prevent the formation of 2-hydroxyphenyl benzoate and p-bromophenyl phenyl carbonate.

  2. Catalysts with Cerium in a Membrane Reactor for the Removal of Formaldehyde Pollutant from Water Effluents

    OpenAIRE

    2016-01-01

    We report the synthesis of cerium oxide, cobalt oxide, mixed cerium, and cobalt oxides and a Ce–Co/Al2O3 membrane, which are employed as catalysts for the catalytic wet oxidation (CWO) reaction process and the removal of formaldehyde from industrial effluents. Formaldehyde is present in numerous waste streams from the chemical industry in a concentration low enough to make its recovery not economically justified but high enough to create an environmental hazard. Common biological degradation ...

  3. Direct Quantification of Rare Earth Elements Concentrations in Urine of Workers Manufacturing Cerium, Lanthanum Oxide Ultrafine and Nanoparticles by a Developed and Validated ICP-MS

    Directory of Open Access Journals (Sweden)

    Yan Li

    2016-03-01

    Full Text Available Rare earth elements (REEs have undergone a steady spread in several industrial, agriculture and medical applications. With the aim of exploring a sensitive and reliable indicator of estimating exposure level to REEs, a simple, accurate and specific ICP-MS method for simultaneous direct quantification of 15 REEs (89Y, 139La, 140Ce, 141Pr, 146Nd, 147Sm, 153Eu, 157Gd, 159Tb, 163Dy, 165Ho, 166Er, 169Tm, 172Yb and 175Lu in human urine has been developed and validated. The method showed good linearity for all REEs in human urine in the concentrations ranging from 0.001–1.000 μg∙L−1 with r2 > 0.997. The limits of detection and quantification for this method were in the range of 0.009–0.010 μg∙L−1 and 0.029–0.037 μg∙L−1, the recoveries on spiked samples of the 15 REEs ranged from 93.3% to 103.0% and the relative percentage differences were less than 6.2% in duplicate samples, and the intra- and inter-day variations of the analysis were less than 1.28% and less than 0.85% for all REEs, respectively. The developed method was successfully applied to the determination of 15 REEs in 31 urine samples obtained from the control subjects and the workers engaged in work with manufacturing of ultrafine and nanoparticles containing cerium and lanthanum oxide. The results suggested that only the urinary levels of La (1.234 ± 0.626 μg∙L−1, Ce (1.492 ± 0.995 μg∙L−1, Nd (0.014 ± 0.009 μg∙L−1 and Gd (0.023 ± 0.010 μg∙L−1 among the exposed workers were significantly higher (p < 0.05 than the levels measured in the control subjects. From these, La and Ce were the primary components, and accounted for 88% of the total REEs. Lanthanum comprised 27% of the total REEs while Ce made up the majority of REE content at 61%. The remaining elements only made up 1% each, with the exception of Dy which was not detected. Comparison with the previously published data, the levels of urinary La and Ce in workers and the control subjects show a

  4. Effects of cerium oxide on the properties of neoprene%氧化铈对氯丁橡胶性能的影响∗

    Institute of Scientific and Technical Information of China (English)

    孙大贵; 李雪; 刘作华; 杜军; 范兴; 陶长元

    2015-01-01

    Surface modification process of cerium oxide (CeO2 )by stearic acid was investigated,CeO2 and modi-fied CeO2 reinforced neoprene (CR)was prepared by means of mixing.The structure of modified CeO2 was characterized by SEM,FT-IR and XRD,vulcanization properties,mechanical properties,aging resistance and thermal stability of CeO2/CR and modified CeO2/CR composite materials were evaluated.Results showed that crystal structure of modified CeO2 was not changed by modification process and stearate salt was generated on the surface.Compared with added unmodified CeO2 ,vulcanization time of CR was shortened by 9.7%,the me-chanical properties,aging resistance and thermal stability of CR enhanced in varying degrees by adding modified CeO2 .%采用硬脂酸对氧化铈(CeO2)进行表面改性,并分别将CeO2和改性CeO2掺混到氯丁橡胶(CR)中,制得CeO2/CR和改性 CeO2/CR 复合材料.通过SEM、FT-IR、XRD 对改性 CeO2的结构进行了表征,研究了 CeO2/CR 和改性 CeO2/CR 复合材料的硫化性能、力学性能、耐老化性能和热稳定性.结果表明,改性 CeO2的晶型结构未发生改变并在其表面生成了硬脂酸铈盐.与添加未改性 CeO2相比,添加改性CeO2使CR的正硫化时间缩短了9.7%,CR 的力学性能、耐老化性能和热稳定性有不同程度的提高.

  5. Direct Quantification of Rare Earth Elements Concentrations in Urine of Workers Manufacturing Cerium, Lanthanum Oxide Ultrafine and Nanoparticles by a Developed and Validated ICP-MS.

    Science.gov (United States)

    Li, Yan; Yu, Hua; Zheng, Siqian; Miao, Yang; Yin, Shi; Li, Peng; Bian, Ying

    2016-03-22

    Rare earth elements (REEs) have undergone a steady spread in several industrial, agriculture and medical applications. With the aim of exploring a sensitive and reliable indicator of estimating exposure level to REEs, a simple, accurate and specific ICP-MS method for simultaneous direct quantification of 15 REEs ((89)Y, (139)La, (140)Ce, (141)Pr, (146)Nd, (147)Sm, (153)Eu, (157)Gd, (159)Tb, (163)Dy, (165)Ho, (166)Er, (169)Tm, (172)Yb and (175)Lu) in human urine has been developed and validated. The method showed good linearity for all REEs in human urine in the concentrations ranging from 0.001-1.000 μg ∙ L(-1) with r² > 0.997. The limits of detection and quantification for this method were in the range of 0.009-0.010 μg ∙ L(-1) and 0.029-0.037 μg ∙ L(-1), the recoveries on spiked samples of the 15 REEs ranged from 93.3% to 103.0% and the relative percentage differences were less than 6.2% in duplicate samples, and the intra- and inter-day variations of the analysis were less than 1.28% and less than 0.85% for all REEs, respectively. The developed method was successfully applied to the determination of 15 REEs in 31 urine samples obtained from the control subjects and the workers engaged in work with manufacturing of ultrafine and nanoparticles containing cerium and lanthanum oxide. The results suggested that only the urinary levels of La (1.234 ± 0.626 μg ∙ L(-1)), Ce (1.492 ± 0.995 μg ∙ L(-1)), Nd (0.014 ± 0.009 μg ∙ L(-1)) and Gd (0.023 ± 0.010 μg ∙ L(-1)) among the exposed workers were significantly higher (p < 0.05) than the levels measured in the control subjects. From these, La and Ce were the primary components, and accounted for 88% of the total REEs. Lanthanum comprised 27% of the total REEs while Ce made up the majority of REE content at 61%. The remaining elements only made up 1% each, with the exception of Dy which was not detected. Comparison with the previously published data, the levels of urinary La and Ce in workers and

  6. TU-F-CAMPUS-T-01: Potential of Using Cerium Oxide Nanoparticles (CONP) for Protecting Healthy Tissue During Accelerated Partial Breast Irradiation (APBI)

    Energy Technology Data Exchange (ETDEWEB)

    Mainali, M [University of Massachusetts Boston/Dana Farber cancer institute, Boston, MA (United States); Ngwa, W [Harvard Medical School, Boston, MA (United States); Cifter, G [University of Massachusetts Lowell/ Dana Farber cancer institute, Boston, MA (United States); Celli, J [University of Massachusetts Boston, Boston, MA (United States)

    2015-06-15

    Purpose: The purpose of this research is to investigate the feasibility of using targeted cerium oxide nanoparticles (CONP) during APBI to protect healthy cells. Methods: In one approach, CONP are assumed to be incorporated in a micrometer-thick polymer film on the surface of routinely used mammosite balloon applicators for sustained in-situ release of the CONP. In case two, CONPs are administered directly into the lumpectomy cavity. The concentration of H{sub 2}O{sub 2} produced by ionizing radiation was estimated from previously published work using short range linear extrapolation. The assessment of CONPs concentration required to absorb corresponding H{sub 2}O{sub 2} to protect healthy tissue was calculated. Fick’s Second law of diffusion was employed to determine the initial concentration of CONP needed to achieve the minimum concentration for radioprotection at distance 1 cm and 2 cm from the lumpectomy cavity during APBI. The study was carried out for different nanoparticle sizes. Results: The initial concentration of CONPs required to get desired radioprotection concentration at 1 cm and 2 cm after 7 days was found to be 0.4089 mg per Kg and 59.7605 g per Kg respectively for 2 nm size nanoparticles. Using concentrations of 5 mg per kg of CONP that have been shown to be used to confer radioprotection (for about 7.97 Gy) in experiments it was observed that 4.5631, 8.5286, 10.9247, 22.0408, 43.6796 and 65.5618 number of days are required to achieve radioprotection at 1 cm for CONP of sizes 2 nm, 3.8 nm, 5 nm, 10 nm, 20 nm, 30 nm, respectively. Conclusion: Our preliminary results show that smaller size (2 nm and 3.8 nm) CONP would be suitable as radio protectant during APBI because they took a reasonable number of days, i.e. less than 10 days to reach tissues of 1 cm or 2 cm thickness.

  7. Synthesis of cerium oxide nanoparticles using Gloriosa superba L. leaf extract and their structural, optical and antibacterial properties.

    Science.gov (United States)

    Arumugam, Ayyakannu; Karthikeyan, Chandrasekaran; Haja Hameed, Abdulrahman Syedahamed; Gopinath, Kasi; Gowri, Shanmugam; Karthika, Viswanathan

    2015-04-01

    CeO2 nanoparticles (NPs) were green synthesized using Gloriosa superba L. leaf extract. The synthesized nanoparticles retained the cubic structure, which was confirmed by X-ray diffraction studies. The oxidation states of the elements (C (1s), O (1s) and Ce (3d)) were confirmed by XPS studies. TEM images showed that the NPs possessed spherical shape and particle size of 5nm. The Ce-O stretching bands were observed at 451cm(-1) and 457cm(-1) from the FT-IR and Raman spectra respectively. The band gap of the CeO2 NPs was estimated as 3.78eV from the UV-visible spectrum. From the photoluminescence measurements, the broad emission composed of eight different bands were found. The antibacterial studies performed against a set of bacterial strains showed that Gram positive (G+) bacteria were relatively more susceptible to the NPs than Gram negative (G-) bacteria. The toxicological behavior of CeO2 NPs was found due to the synthesized NPs with uneven ridges and oxygen defects in CeO2 NPs. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Spectrophotometric determination of cerium with methylthymol blue in the presence of oxalate and cyanide as masking agents

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera-Martin, A.; Izquierdo-Hornillos, R.; Quejido-Cabezas, A.J.; Peral-Fernandez, J.L. (Universidad Complutense de Madrid (Spain). Facultad de Ciencias Quimicas)

    1983-04-01

    The spectrophotometric determination of cerium can be carried out by several methods, which involve either the formation of complexes of cerium(III) and cerium(IV) or the oxidation of suitable reagents by cerium(IV) and further measuring the intensity of the colour of the oxidised matter. The latter methods show a lack of selectivity and low sensitivity owing to the nature of the redox reaction. The methods that involve the formation of complexes have also been shown to have low selectivity and sensitivity. However, the most useful methods are those based on the complexes of cerium(III) with Xylenol Orange and Methylthymol Blue (MTB), but they are affected by many interferences. In this work the reaction of cerium(III) with MTB in the presence of oxalate and cyanide ions was studied at pH 10.2, which improves the sensitivity and the selectivity of the determination of cerium.

  9. Synthesis of cerium oxide nanoparticles using Gloriosa superba L. leaf extract and their structural, optical and antibacterial properties

    Energy Technology Data Exchange (ETDEWEB)

    Arumugam, Ayyakannu, E-mail: sixmuga@yahoo.com [Department of Nanoscience and Technology, Alagappa University, Karaikudi 630 004, Tamil Nadu (India); Karthikeyan, Chandrasekaran; Haja Hameed, Abdulrahman Syedahamed [PG and Research Department of Physics, Jamal Mohamed College, Tiruchirappalli 620 020, Tamil Nadu (India); Gopinath, Kasi; Gowri, Shanmugam; Karthika, Viswanathan [Department of Nanoscience and Technology, Alagappa University, Karaikudi 630 004, Tamil Nadu (India)

    2015-04-01

    CeO{sub 2} nanoparticles (NPs) were green synthesized using Gloriosa superba L. leaf extract. The synthesized nanoparticles retained the cubic structure, which was confirmed by X-ray diffraction studies. The oxidation states of the elements (C (1s), O (1s) and Ce (3d)) were confirmed by XPS studies. TEM images showed that the NPs possessed spherical shape and particle size of 5 nm. The Ce–O stretching bands were observed at 451 cm{sup −1} and 457 cm{sup −1} from the FT-IR and Raman spectra respectively. The band gap of the CeO{sub 2} NPs was estimated as 3.78 eV from the UV–visible spectrum. From the photoluminescence measurements, the broad emission composed of eight different bands were found. The antibacterial studies performed against a set of bacterial strains showed that Gram positive (G +) bacteria were relatively more susceptible to the NPs than Gram negative (G −) bacteria. The toxicological behavior of CeO{sub 2} NPs was found due to the synthesized NPs with uneven ridges and oxygen defects in CeO{sub 2} NPs. - Highlights: • Phytosynthesis of CeO{sub 2} NPs using Gloriosa superba leaf extract • Single step synthesis • Characterized by XRD, XPS, TEM, FTIR, Raman, UV–vis, PL and TG/DTA analyses • CeO{sub 2} NPs were of spherical shape with an average size of 5 nm. • CeO{sub 2} NPs showed highly potent antibacterial activity.

  10. Thermoluminescence of magnesium oxide doped with cerium and lithium obtained by a glycine-based solution combustion method

    Energy Technology Data Exchange (ETDEWEB)

    Escobar O, F. M.; Orante B, V. R.; Cruz V, C. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Bernal, R., E-mail: flor.escobaroc@gmail.com [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico)

    2015-10-15

    Full text: It is well known that glycine, fulfills two principal purposes: first, complexes with metal cations formed, which increases their solubility and prevents selective precipitation as water is evaporated; and second, it serves as fuel for the combustion reaction, being oxidized by the nitrate ions. The glycine molecule has a carboxylic acid group at one end and an amine group at the other end, both of which can participate in the complexation of metal ions. This zwitterionic character allows effective complexation with metal cations of different ionic size. Novel Mg O:Ce{sup 3+}, Li{sup +} phosphor was obtained for the very first time by solution combustion synthesis (Scs) in which a redox combustion process between metallic nitrates and glycine at 500 degrees C was accomplished. The powder samples obtained were annealed at 900 degrees C during 2 h in air. X-ray diffraction (XRD) results showed the face-centered cubic (fcc) phase of Mg O as well as the presence of CeO{sub 2} for the annealed powder samples. Photoluminescence emission spectra showed the characteristic Ce{sup 3+} peak located at 520 nm. The thermoluminescence glow curve obtained after exposure to beta radiation of these samples, displayed three maxima located at ∼ 108 degrees C, ∼ 210 degrees C, and ∼ 310 degrees C. Results from experiments such as dose response and fading showed that annealed Mg O:Ce{sup 3+}, Li{sup +} powder obtained by Scs is a promising material for radiation dosimetry applications. (Author)

  11. In vitro skin decontamination of the organophosphorus pesticide Paraoxon with nanometric cerium oxide CeO2.

    Science.gov (United States)

    Salerno, Alicia; Devers, Thierry; Bolzinger, Marie-Alexandrine; Pelletier, Jocelyne; Josse, Denis; Briançon, Stéphanie

    2017-04-01

    Organophosphorus compounds (OP), which mainly penetrate via the percutaneous pathway, represent a threat for both military and civilians. Body surface decontamination is vital to prevent victims poisoning. The development of a cost-effective formulation, which could be efficient and easy to handle in case of mass contamination, is therefore crucial. Metal oxides nanoparticles, due their large surface areas and the large amount of highly reactive sites, present high reactivity towards OP. First, this study aimed at evaluating the reaction of CeO2 nanoparticles, synthetized by microwave path and calcined at 500 or 600 °C, with Paraoxon (POX) in aqueous solution. Results showed that both nanoparticles degraded 60%-70% of POX. CeO2 calcined at 500 °C, owing to its larger specific area, was the most effective. Moreover, the degradation was significantly increased under Ultra-Violet irradiation (initial degradation rate doubled). Then, skin decontamination was studied in vitro using the Franz cell method with pig-ear skin samples. CeO2 powder and an aqueous suspension of CeO2 (CeO2-W) were applied 1 h after POX exposure. The efficiency of decontamination, including removal and/or degradation of POX, was compared to Fuller's earth (FE) and RSDL lotion which are, currently, the most efficient systems for skin decontamination. CeO2-W and RSDL were the most efficient to remove POX from the skin surface and decrease skin absorption by 6.4 compared to the control not decontaminated. FE reduced significantly (twice) the absorbed fraction of POX, contrarily to CeO2 powder. Considering only the degradation rate of POX, the products ranged in the order CeO2 > RSDL > CeO2-W > FE (no degradation). This study showed that CeO2 nanoparticles are a promising material for skin decontamination of OP if formulated as a dispersion able to remove POX like CeO2-W and to degrade it as CeO2 powder.

  12. Selective catalytic reduction of NOx with NH3 over iron-cerium-tungsten mixed oxide catalyst prepared by different methods

    Science.gov (United States)

    Xiong, Zhi-bo; Liu, Jing; Zhou, Fei; Liu, Dun-yu; Lu, Wei; Jin, Jing; Ding, Shi-fa

    2017-06-01

    A series of magnetic Fe0.85Ce0.10W0.05Oz catalysts were synthesized by three different methods(Co-precipitation(Fe0.85Ce0.10W0.05Oz-CP), Hydrothermal treatment assistant critic acid sol-gel method(Fe0.85Ce0.10W0.05Oz-HT) and Microwave irradiation assistant critic acid sol-gel method(Fe0.85Ce0.10W0.05Oz-MW)), and the catalytic activity was evaluated for selective catalytic reduction of NO with NH3. The catalyst was characterized by XRD, N2 adsorption-desorption, XPS, H2-TPR and NH3-TPD. Among the tested catalysts, Fe0.85Ce0.10W0.05Oz-MW shows the highest NOx conversion over per gram in unit time with NOx conversion of 60.8% at 350 °C under a high gas hourly space velocity of 1,200,000 ml/(g h). Different from Fe0.85Ce0.10W0.05Oz-CP catalyst, there exists a large of iron oxide crystallite(γ-Fe2O3 and α-Fe2O3) scattered in Fe0.85Ce0.10W0.05Oz catalysts prepared through hydrothermal treatment or microwave irradiation assistant critic acid sol-gel method, and higher iron atomic concentration on their surface. And Fe0.85Ce0.10W0.05Oz-MW shows higher surface absorbed oxygen concentration and better dispersion compared with Fe0.85Ce0.10W0.05Oz-HT catalyst. These features were favorable for the high catalytic performance of NO reduction with NH3 over Fe0.85Ce0.10W0.05Oz-MW catalyst.

  13. Diesel/biodiesel soot oxidation with ceo2 and ceo2-zro2-modified cordierites: a facile way of accounting for their catalytic ability in fuel combustion processes

    Directory of Open Access Journals (Sweden)

    Rodrigo F. Silva

    2011-01-01

    Full Text Available CeO2 and mixed CeO2-ZrO2 nanopowders were synthesized and efficiently deposited onto cordierite substrates, with the evaluation of their morphologic and structural properties through XRD, SEM, and FTIR. The modified substrates were employed as outer heterogeneous catalysts for reducing the soot originated from the diesel and diesel/biodiesel blends incomplete combustion. Their activity was evaluated in a diesel stationary motor, and a comparative analysis of the soot emission was carried out through diffuse reflectance spectroscopy. The analyses have shown that the catalyst-impregnated cordierite samples are very efficient for soot oxidation, being capable of reducing the soot emission in more than 60%.

  14. Rare earth metal doped CeO2-based catalytic materials for diesel soot oxidation at lower temperatures

    Institute of Scientific and Technical Information of China (English)

    A Rangaswamy; Putla Sudarsanam; Benjaram M Reddy

    2015-01-01

    In this work, the influence of trivalent rare-earth dopants (Sm and La) on the structure-activity properties of CeO2 was thor-oughly studied for diesel soot oxidation. For this, an optimized 40%of Sm and La was incorporated into the CeO2 using a facile co-precipitation method from ultra-high dilute aqueous solutions. A systematic physicochemical characterization was carried out using X-ray diffraction (XRD), transmission electron microscopy (TEM), Brumauer-Emmett-teller method (BET) surface area, X-ray pho-toelectron spectroscopy (XPS), Raman, and H2-temperature programmed reduction (TPR) techniques. The soot oxidation efficiency of the catalysts was investigated using a thermogravimetric method. The XRD results suggested the formation of nanocrystalline sin-gle phase CeO2-Sm2O3 and CeO2-La2O3 solid solutions. The Sm-and La-doped CeO2 materials exhibited smaller crystallite size and higher BET surface area compared with the pure CeO2. Owing to the difference in the oxidation states of the dopants (Sm3+and La3+) and the Ce4+, a number of oxygen vacancies were generated in CeO2-Sm2O3 and CeO2-La2O3 samples. The H2-TPR studies evidenced the improved reducible nature of the CeO2-Sm2O3 and CeO2-La2O3 samples compared with the CeO2. It was found that the addition of Sm and La to the CeO2 outstandingly enhanced its catalytic efficiency for the oxidation of diesel soot. The observed 50%soot con-version temperatures for the CeO2-Sm2O3, CeO2-La2O3 and CeO2 were~790, 843 and 864 K (loose contact), respectively, and similar activity order was also found under the tight contact condition. The high soot oxidation efficacy of the CeO2-Sm2O3 sample was at-tributed to numerous catalytically favourable properties, like smaller crystallite size, larger surface area, abundant oxygen vacancies, and superior reducible nature.

  15. Biodiesel versus diesel exposure: Enhanced pulmonary inflammation, oxidative stress, and differential morphological changes in the mouse lung

    Energy Technology Data Exchange (ETDEWEB)

    Yanamala, Naveena, E-mail: wqu1@cdc.gov [Pathology and Physiology Research Branch/NIOSH/CDC, Morgantown, WV 26505 (United States); Hatfield, Meghan K., E-mail: wla4@cdc.gov [Pathology and Physiology Research Branch/NIOSH/CDC, Morgantown, WV 26505 (United States); Farcas, Mariana T., E-mail: woe7@cdc.gov [Pathology and Physiology Research Branch/NIOSH/CDC, Morgantown, WV 26505 (United States); Schwegler-Berry, Diane [Pathology and Physiology Research Branch/NIOSH/CDC, Morgantown, WV 26505 (United States); Hummer, Jon A., E-mail: qzh3@cdc.gov [Office of Mine Safety and Health Research/NIOSH/CDC, Pittsburgh, PA 15236 (United States); Shurin, Michael R., E-mail: shurinmr@upmc.edu [Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA (United States); Birch, M. Eileen, E-mail: mib2@cdc.gov [NIOSH/CDC, 4676 Columbia Parkway, Cincinnati, OH 45226 (United States); Gutkin, Dmitriy W., E-mail: dwgutkin@hotmail.com [Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA (United States); Kisin, Elena, E-mail: edk8@cdc.gov [Pathology and Physiology Research Branch/NIOSH/CDC, Morgantown, WV 26505 (United States); Kagan, Valerian E., E-mail: kagan@pitt.edu [Department of Environmental and Occupational Health, University of Pittsburgh, PA (United States); Bugarski, Aleksandar D., E-mail: zjl1@cdc.gov [Office of Mine Safety and Health Research/NIOSH/CDC, Pittsburgh, PA 15236 (United States); Shvedova, Anna A., E-mail: ats1@cdc.gov [Pathology and Physiology Research Branch/NIOSH/CDC, Morgantown, WV 26505 (United States); Department Physiology and Pharmacology, WVU, Morgantown, WV 26505 (United States)

    2013-10-15

    The use of biodiesel (BD) or its blends with petroleum diesel (D) is considered to be a viable approach to reduce occupational and environmental exposures to particulate matter (PM). Due to its lower particulate mass emissions compared to D, use of BD is thought to alleviate adverse health effects. Considering BD fuel is mainly composed of unsaturated fatty acids, we hypothesize that BD exhaust particles could induce pronounced adverse outcomes, due to their ability to readily oxidize. The main objective of this study was to compare the effects of particles generated by engine fueled with neat BD and neat petroleum-based D. Biomarkers of tissue damage and inflammation were significantly elevated in lungs of mice exposed to BD particulates. Additionally, BD particulates caused a significant accumulation of oxidatively modified proteins and an increase in 4-hydroxynonenal. The up-regulation of inflammatory cytokines/chemokines/growth factors was higher in lungs upon BD particulate exposure. Histological evaluation of lung sections indicated presence of lymphocytic infiltrate and impaired clearance with prolonged retention of BD particulate in pigment laden macrophages. Taken together, these results clearly indicate that BD exhaust particles could exert more toxic effects compared to D. - Highlights: • Exposure of mice to BDPM caused higher pulmonary toxicity compared to DPM. • Oxidative stress and inflammation were higher in BD vs to D exposed mice. • Inflammatory lymphocyte infiltrates were seen only in lungs of mice exposed to BD. • Ineffective clearance, prolonged PM retention was present only after BD exposure.

  16. Structure–activity relationships of Pt/Al2O3 catalysts for CO and NO oxidation at diesel exhaust conditions

    DEFF Research Database (Denmark)

    Boubnov, Alexey; Dahl, Søren; Johnson, Erik

    2012-01-01

    Structure–performance relationships for Pt/Al2O3 catalysts with mean Pt particle sizes of 1, 2, 3, 5 and 10nm are investigated for the catalytic oxidation of CO and NO under lean-burning diesel exhaust conditions. The most active catalysts for CO oxidation exhibit Pt particles of 2–3nm, having...... a large fraction of low-coordinated and reactive surface Pt atoms. Exploiting in situ XAFS, we find that a reversible Pt surface oxidation is connected to high CO conversion. NO oxidation is most efficient over the catalysts with the largest Pt particles mainly exhibiting surface Pt atoms on planar facets....... An irreversible Pt oxide formation observed during NO oxidation is a possible deactivation route and we suggest that the most active sites for NO oxidation are the ones least prone to surface oxidation. When both CO and NO are present in the reaction mixture, activity is increased for both reactions, suggesting...

  17. Ultrathin, epitaxial cerium dioxide on silicon

    Science.gov (United States)

    Flege, Jan Ingo; Kaemena, Björn; Höcker, Jan; Bertram, Florian; Wollschläger, Joachim; Schmidt, Thomas; Falta, Jens

    2014-03-01

    It is shown that ultrathin, highly ordered, continuous films of cerium dioxide may be prepared on silicon following substrate prepassivation using an atomic layer of chlorine. The as-deposited, few-nanometer-thin Ce2O3 film may very effectively be converted at room temperature to almost fully oxidized CeO2 by simple exposure to air, as demonstrated by hard X-ray photoemission spectroscopy and X-ray diffraction. This post-oxidation process essentially results in a negligible loss in film crystallinity and interface abruptness.

  18. Elaboration and characterization of thin solid films containing cerium

    Science.gov (United States)

    Hamdi, S.; Guerfi, S.; Siab, R.

    2009-11-01

    Cerium oxide films are widely studied as a promising alternative to Cr(VI) based pre-treatments for the corrosion protection of different metals and alloys. Cathodic electrodeposition of Cerium containing thin films was realised on TA6V substrates from a Ce(NO3)3, 6H2O and mixed water-ethyl alcohol solutions at 0.01 M. Experimental conditions to obtain homogeneous and crack free thin films were determined. The deposited cerium quantity appears proportional to the quantity of electricity used, as indicated by the Faraday law. Subsequent thermal treatment lead to a CeO2 coating, expected to provide an increase of TA6V oxidation resistance at high temperatures. The deposits were characterized by differential scanning calorimetry (DSC), optical and scanning electron microscopies.

  19. Analysing the causes of chronic cough: relation to diesel exhaust, ozone, nitrogen oxides, sulphur oxides and other environmental factors

    Directory of Open Access Journals (Sweden)

    Wagner Ulrich

    2006-05-01

    Full Text Available Abstract Air pollution remains a leading cause of many respiratory diseases including chronic cough. Although episodes of incidental, dramatic air pollution are relatively rare, current levels of exposure of pollutants in industrialized and developing countries such as total articles, diesel exhaust particles and common cigarette smoke may be responsible for the development of chronic cough both in children and adults. The present study analyses the effects of common environmental factors as potential causes of chronic cough. Different PubMed-based researches were performed that related the term cough to various environmental factors. There is some evidence that chronic inhalation of diesel can lead to the development of cough. For long-term exposure to nitrogen dioxide (NO2, children were found to exhibit increased incidences of chronic cough and decreased lung function parameters. Although a number of studies did not show that outdoor pollution directly causes the development of asthma, they have demonstrated that high levels pollutants and their interaction with sunlight produce ozone (O3 and that repeated exposure to it can lead to chronic cough. In summary, next to the well-known air pollutants which also include particulate matter and sulphur dioxide, a number of other indoor and outdoor pollutants have been demonstrated to cause chronic cough and therefore, environmental factors have to be taken into account as potential initiators of both adult and pediatric chronic cough.

  20. Hydrogen production in a 5 kW Diesel Oxidative Steam Reformer

    Energy Technology Data Exchange (ETDEWEB)

    Sopena, D.; Melgar, A.; Briceno, Y. [Fundacion CIDAUT- Parque Tecnologico de Boecillo, P. 209, 47151 Boecillo (Valladolid) (Spain); Navarro, R.M.; Alvarez-Galvan, M.C. [Instituto de Catalisis y Petroquimica (ICP-CSIC), C/ Marie Curie 2, Campus de Cantoblanco (Madrid) (Spain); Rosa, F. [Instituto Nacional de Tecnica Aeroespacial (INTA), Carretera San Juan del Puerto - Matalascanas, km 33, 21130 Mazagon Moguer (Huelva) (Spain)

    2006-07-01

    This paper presents a reformer prototype for the production of the necessary H{sub 2} to supply a 5 kW PEMFC and its first results. The fuel processor consists of an OSR and a WGS and a PROX reactors. The design of the system was carried out with a one-dimensional model. The mixture chamber was specially studied with a CFD code (Fluent), taking into account the effect of fuel evaporation and the cool flame process. The aim of the designed facility is to be able of characterising each component and controlling each working parameter. Eventually, using diesel as fuel, results from the mixture chamber, OSR, WGS and PROX reactors are presented. It also includes conclusions and future works. (authors)

  1. Role of oxidative stress on diesel-enhanced influenza infection in mice

    Directory of Open Access Journals (Sweden)

    Linak William P

    2010-11-01

    Full Text Available Abstract Numerous studies have shown that air pollutants, including diesel exhaust (DE, reduce host defenses, resulting in decreased resistance to respiratory infections. This study sought to determine if DE exposure could affect the severity of an ongoing influenza infection in mice, and examine if this could be modulated with antioxidants. BALB/c mice were treated by oropharyngeal aspiration with 50 plaque forming units of influenza A/HongKong/8/68 and immediately exposed to air or 0.5 mg/m3 DE (4 hrs/day, 14 days. Mice were necropsied on days 1, 4, 8 and 14 post-infection and lungs were assessed for virus titers, lung inflammation, immune cytokine expression and pulmonary responsiveness (PR to inhaled methacholine. Exposure to DE during the course of infection caused an increase in viral titers at days 4 and 8 post-infection, which was associated with increased neutrophils and protein in the BAL, and an early increase in PR. Increased virus load was not caused by decreased interferon levels, since IFN-β levels were enhanced in these mice. Expression and production of IL-4 was significantly increased on day 1 and 4 p.i. while expression of the Th1 cytokines, IFN-γ and IL-12p40 was decreased. Treatment with the antioxidant N-acetylcysteine did not affect diesel-enhanced virus titers but blocked the DE-induced changes in cytokine profiles and lung inflammation. We conclude that exposure to DE during an influenza infection polarizes the local immune responses to an IL-4 dominated profile in association with increased viral disease, and some aspects of this effect can be reversed with antioxidants.

  2. Ceria Prepared by Flame Spray Pyrolysis as an Efficient Catalyst for Oxidation of Diesel Soot

    DEFF Research Database (Denmark)

    Christensen, Jakob Munkholt; Deiana, Davide; Grunwaldt, Jan-Dierk

    2014-01-01

    Ceria has been prepared by flame spray pyrolysis and tested for activity in catalytic soot oxidation. In tight contact with soot the oxidation activity (measured in terms of the temperature of maximal oxidation rate, Tmax) of the flame made ceria is among the highest reported for CeO2. This can...... to a significant degree be ascribed to the large surface area achieved with the flame spray pyrolysis method. The importance of the inherent soot reactivity for the catalytic oxidation was studied using various soot samples, and the reactivity of the soot was found to have a significant impact, as the Tmax......-value for oxidation in tight contact with a catalyst scaled linearly with the Tmax-value in non-catalytic soot oxidation. The Tmax-value in non-catalytic soot oxidation was in turn observed to scale linearly with the H/C ratio of the carbonaceous materials....

  3. Investigations on the effect of chlorine in lubricating oil and the presence of a diesel oxidation catalyst on PCDD/F releases from an internal combustion engine.

    Science.gov (United States)

    Dyke, Patrick H; Sutton, Mike; Wood, David; Marshall, Jonathan

    2007-04-01

    This paper reports on an intensive study into releases of polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated furans (PCDF) and polychlorinated biphenyls (PCB) from a diesel engine and the analysis of PCDD/F and PCB in crankcase lubricating oil. Experimental conditions were set and carefully controlled in order to maximize the possible impact of, and our ability to measure the effect of, changes in the levels of chlorine in the lubricant. Emissions to air were measured using modified EPA methods following the principles of the European EN 1948 standards. A series of 40 experimental runs were completed using three reference lubricants formulated to have three levels of chlorine present as a residual component (at levels of 12, 131 and 259 mg kg(-1) or ppm). The engine was run with and without the diesel oxidation catalyst. All lubricants were realistic oils and the use of unrealistic additives or doping of components - particularly chlorine - in the fuel and lubricant was carefully avoided. Analysis of fuel and lubricant (before and after testing) samples required strenuous attention to achieve acceptable recoveries and showed non-detectable levels of PCB and PCDD/F at a detection limit of around 1.5 ng I-TEQ kg(-1) (ppt), indistinguishable from the laboratory blank. The testing demonstrated the need for extreme care to be taken in developing measurement methods that are sufficiently sensitive for measuring chlorine content of fluids and PCDD/F in oils, the latter being particularly challenging. Mean emissions of PCDD/F with the diesel oxidation catalyst in place were 23 pg I-TEQ l(-1) of fuel and with the diesel oxidation catalyst removed 97 pg I-TEQ l(-1) of fuel. The results of this testing showed that the emissions of PCDD/F were greatly reduced by the presence of a diesel oxidation catalyst in the exhaust, a finding that has not been explicitly tested in previous work. They also show that emissions from the engine were not controlled by the level of

  4. Corrosion protection properties and interfacial adhesion mechanism of an epoxy/polyamide coating applied on the steel surface decorated with cerium oxide nanofilm: Complementary experimental, molecular dynamics (MD) and first principle quantum mechanics (QM) simulation methods

    Science.gov (United States)

    Bahlakeh, Ghasem; Ramezanzadeh, Bahram; Saeb, Mohammad Reza; Terryn, Herman; Ghaffari, Mehdi

    2017-10-01

    The effect of cerium oxide treatment on the corrosion protection properties and interfacial interaction of steel/epoxy was studied by electrochemical impedance spectroscopy, (EIS) classical molecular dynamics (MD) and first principle quantum mechanics (QM) simulation methods X-ray photoelectron spectroscopy (XPS) was used to verify the chemical composition of the Ce film deposited on the steel. To probe the role of the curing agent in epoxy adsorption, computations were compared for an epoxy, aminoamide and aminoamide modified epoxy. Moreover, to study the influence of water on interfacial interactions the MD simulations were executed for poly (aminoamide)-cured epoxy resin in contact with the different crystallographic cerium dioxide (ceria, CeO2) surfaces including (100), (110), and (111) in the presence of water molecules. It was found that aminoamide-cured epoxy material was strongly adhered to all types of CeO2 substrates, so that binding to ceria surfaces followed the decreasing order CeO2 (111) > CeO2 (100) > CeO2 (110) in both dry and wet environments. Calculation of interaction energies noticed an enhanced adhesion to metal surface due to aminoamide curing of epoxy resin; where facets (100) and (111) revealed electrostatic and Lewis acid-base interactions, while an additional hydrogen bonding interaction was identified for CeO2 (110). Overall, MD simulations suggested decrement of adhesion to CeO2 in wet environment compared to dry conditions. Additionally, contact angle, pull-off test, cathodic delamination and salt spray analyses were used to confirm the simulation results. The experimental results in line with modeling results revealed that Ce layer deposited on steel enhanced substrate surface free energy, work of adhesion, and interfacial adhesion strength of the epoxy coating. Furthermore, decrement of adhesion of epoxy to CeO2 in presence of water was affirmed by experimental results. EIS results revealed remarkable enhancement of the corrosion

  5. The iron and cerium oxide influence on the electric conductivity and the corrosion resistance of anodized aluminium; A influencia do ferro e do oxido de cerio sobre a condutividade eletrica e a resistencia a corrosao do aluminio anodizado

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Kellie Provazi de

    2006-07-01

    The influence of different treatments on the aluminum system covered with aluminum oxide is investigated. The aluminum anodization in sulphuric media and in mixed sulphuric and phosphoric media was used to alter the corrosion resistance, thickness, coverage degree and microhardness of the anodic oxide. Iron electrodeposition inside the anodic oxide was used to change its electric conductivity and corrosion resistance. Direct and pulsed current were used for iron electrodeposition and the Fe(SO{sub 4}){sub 2}(NH{sub 4}){sub 2}.6H{sub 2}O electrolyte composition was changed with the addition of boric and ascorbic acids. To the sealing treatment the CeCl{sub 3} composition was varied. The energy dispersive x-ray (EDS), the x-ray fluorescence spectroscopy (FRX) and the morphologic analysis by scanning electronic microscopy (SEM) allowed to verify that, the pulsed current increase the iron content inside the anodic layer and that the use of the additives inhibits the iron oxidation. The chronopotentiometric curves obtained during iron electrodeposition indicated that the boric and ascorbic acids mixture increased the electrodeposition process efficiency. The electrochemical impedance spectroscopy (EIE), the Vickers (Hv) microhardness measurements and morphologic analysis evidenced that the sealing treatment improves the corrosion resistance of the anodic film modified with iron. The electrical impedance (EI) technique allowed to prove the electric conductivity increase of the anodized aluminum with iron electrodeposited even after the cerium low concentration treatment. Iron nanowires were prepared by using the anodic oxide pores as template. (author)

  6. Effects of Particle Filters and Accelerated Engine Replacement on Heavy-Duty Diesel Vehicle Emissions of Black Carbon, Nitrogen Oxides, and Ultrafine Particles

    Science.gov (United States)

    Kirchstetter, T.; Preble, C.; Dallmann, T. R.; DeMartini, S. J.; Tang, N. W.; Kreisberg, N. M.; Hering, S. V.; Harley, R. A.

    2013-12-01

    Diesel particle filters have become widely used in the United States since the introduction in 2007 of a more stringent exhaust particulate matter emission standard for new heavy-duty diesel vehicle engines. California has instituted additional regulations requiring retrofit or replacement of older in-use engines to accelerate emission reductions and air quality improvements. This presentation summarizes pollutant emission changes measured over several field campaigns at the Port of Oakland in the San Francisco Bay Area associated with diesel particulate filter use and accelerated modernization of the heavy-duty truck fleet. Pollutants in the exhaust plumes of hundreds of heavy-duty trucks en route to the Port were measured in 2009, 2010, 2011, and 2013. Ultrafine particle number, black carbon (BC), nitrogen oxides (NOx), and nitrogen dioxide (NO2) concentrations were measured at a frequency ≤ 1 Hz and normalized to measured carbon dioxide concentrations to quantify fuel-based emission factors (grams of pollutant emitted per kilogram of diesel consumed). The size distribution of particles in truck exhaust plumes was also measured at 1 Hz. In the two most recent campaigns, emissions were linked on a truck-by-truck basis to installed emission control equipment via the matching of transcribed license plates to a Port truck database. Accelerated replacement of older engines with newer engines and retrofit of trucks with diesel particle filters reduced fleet-average emissions of BC and NOx. Preliminary results from the two most recent field campaigns indicate that trucks without diesel particle filters emit 4 times more BC than filter-equipped trucks. Diesel particle filters increase emissions of NO2, however, and filter-equipped trucks have NO2/NOx ratios that are 4 to 7 times greater than trucks without filters. Preliminary findings related to particle size distribution indicate that (a) most trucks emitted particles characterized by a single mode of approximately

  7. Recovery of microbial diversity and activity during bioremediation following chemical oxidation of diesel contaminated soils

    NARCIS (Netherlands)

    Sutton, N.B.; Langenhoff, A.A.M.; Hidalgo Lasso, D.; Zaan, van der B.M.; Gaans, van P.; Maphosa, F.; Smidt, H.; Grotenhuis, J.T.C.; Rijnaarts, H.H.M.

    2014-01-01

    To improve the coupling of in situ chemical oxidation and in situ bioremediation, a systematic analysis was performed of the effect of chemical oxidation with Fenton's reagent, modified Fenton's reagent, permanganate, or persulfate, on microbial diversity and activity during 8 weeks of incubation in

  8. Recovery of microbial diversity and activity during bioremediation following chemical oxidation of diesel contaminated soils

    NARCIS (Netherlands)

    Sutton, N.B.; Langenhoff, A.A.M.; Hidalgo Lasso, D.; Zaan, van der B.M.; Gaans, van P.; Maphosa, F.; Smidt, H.; Grotenhuis, J.T.C.; Rijnaarts, H.H.M.

    2014-01-01

    To improve the coupling of in situ chemical oxidation and in situ bioremediation, a systematic analysis was performed of the effect of chemical oxidation with Fenton's reagent, modified Fenton's reagent, permanganate, or persulfate, on microbial diversity and activity during 8 weeks of incubation in

  9. Antioxidant (A-tocopherol acetate) effect on oxidation stability and NOx emission reduction in methyl ester of Annona oil operated diesel engine

    Science.gov (United States)

    Senthil, R.; Silambarasan, R.; Pranesh, G.

    2016-11-01

    There is a major drawback while using biodiesel as a alternate fuel for compression ignition diesel engine due to lower heating value, higher viscosity, higher density and higher oxides of nitrogen emission. To minimize these drawbacks, fuel additives can contribute towards engine performance and exhaust emission reduction either directly or indirectly. In this current work, the test was conducted to investigate the effect of antioxidant additive (A-tocopherol acetate) on oxidation stability and NOx emission in a of Annona methyl ester oil (MEAO) fueled diesel engine. The A-tocopherol acetate is mixed in different concentrations such as 0.01, 0.02, 0.03 and 0.04% with 100% by vol MEAO. It is concluded that the antioxidant additive very effective in increasing the oxidation stability and in controlling the NOx emission. Further, the addition of antioxidant additive is slight increase the HC, CO and smoke emissions. Hence, A-tocopherol acetate is very effective in controlling the NOx emission with MEAO operated diesel engine without any major modification.

  10. Oxidative Desulfurization of Diesel Fuel with Hydrogen Peroxide Using Na2WO4 s Catalyst

    Institute of Scientific and Technical Information of China (English)

    Sun Xin; Long Jun; Xu Benjing; Xie Chaogang

    2009-01-01

    Oxidative desulfurization was performed on Na2WO4 catalyst in the presence of hydrogen peroxide and acetic acid under mild reaction conditions (atmospheric pressure and temperature range of 293-343 K). Different organic com-pounds including benzothiophene (BT), dibenzothiophene (DBT), 4, 6-dimethyl dibenzothiophene (4, 6-DMDBT) were used to investigate the reactivity of this catalyst, and the effect of various parameters, such as temperature, solvents and the amount of oxidant reagent used in oxidative desulfurization reaction, was also examined. The results showed that the Na2WO4-H2O2 system was very effective for oxidative desulfurization, and the oxidation of BT, DBT and 4, 6-DMDBT was influ-enced by different parameters.

  11. Preparation of ultrafine Ce-based oxide nanoparticles and their catalytic performances for diesel soot combustion

    Institute of Scientific and Technical Information of China (English)

    韦岳长; 赵震; 焦金庆; 刘坚; 段爱军; 姜桂元

    2014-01-01

    The ultrafine Ce-based oxide nanoparticles with different element dopings (Zr, Y) were synthesized by the method of mi-cropores-diffused coprecipitation (MDC) using ammonia solution as the precipitation agent. The activities of the catalysts for soot oxidation were evaluated by the temperature-programmed oxidation (TPO) reaction. Ce-based oxides prepared in this study exhibited high catalytic activity for soot oxidation under the condition of loose contact between soot particles and catalysts, and the catalytic ac-tivity of ultrafine Ce0.9Zr0.1O2 nanoparticle for soot combustion was the highest, whose T10, T50 and SCO2m was 364, 442 ºC and 98.3%, respectively. All catalysts were systematically characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brumauer-Emett-Teller (BET), Fourier transform infrared spectroscopy (FT-IR) and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). It was indicated that the MDC method could prepare the ultrafine Ce-based oxide nanoparticles whose the crystal lattice were perfect, and the BET surface area and average crystal size of the ultrafine nanoparticles changed with the different element dopings (Zr, Y). The H2-TPR measurements showed that the ultrafine Ce-based ox-ide nanoparticles with the doping-Zr cation could be favorable for improving the redox property of the catalysts.

  12. The PL "violet shift" of cerium dioxide on silicon

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    CeO2 thin film was fabricated by dual ion beam epitaxial technique. The phenomenon of PL violet shift at room temperature was observed, and the distance of shift was about 65 nm. After the analysis of crystal structure and valence in the compound were carried out by XRD and XPS technique, it was concluded that the PL shift was related with valence of cerium ion in the oxides. When the valence of cerium ion varied from tetravalence to trivalence, the PL peak position would move from blue region to violet region and the phenomenon of "violet shift" was observed.

  13. Cerium doped red mud catalytic ozonation for bezafibrate degradation in wastewater: Efficiency, intermediates, and toxicity.

    Science.gov (United States)

    Xu, Bingbing; Qi, Fei; Sun, Dezhi; Chen, Zhonglin; Robert, Didier

    2016-03-01

    In this study, the performance of bezafibrate (BZF) degradation and detoxification in the aqueous phase using cerium-modified red mud (RM) catalysts prepared using different cerium sources and synthesis methods were evaluated. Experimental results showed that the surface cerium modification was responsible for the development of the catalytic activity of RM and this was influenced by the cerium source and the synthesis method. Catalyst prepared from cerium (IV) by precipitation was found to show the best catalytic activity in BZF degradation and detoxification. Reactive oxygen species including peroxides, hydroxyl radicals, and super oxide ions were identified in all reactions and we proposed the corresponding catalytic reaction mechanism for each catalyst that prepared from different cerium source and method. This was supported by the intermediates profiles that were generated upon BZF degradation. The surface and the structural properties of cerium-modified RM were characterized in detail by several analytical methods. Two interesting findings were made: (1) the surface texture (specific surface area and mesoporous volume) influenced the catalytic reaction pathway; and (2) Ce(III) species and oxygen vacancies were generated on the surface of the catalyst after cerium modification. This plays an important role in the development of the catalytic activity.

  14. Thermodynamic Calculation among Cerium, Oxygen, and Sulfur in Liquid Iron

    Science.gov (United States)

    Pan, Fei; Zhang, Jian; Chen, Hao-Long; Su, Yen-Hsun; Su, Yen-Hao; Hwang, Weng-Sing

    2016-10-01

    Thermodynamic calculation has been applied to predict the inclusion formation in molten SS400 steel. When the Cerium addition in liquid iron is 70 ppm and the initial Oxygen and Sulphur are both 110 ppm, the formation of oxides containing Cerium would experience the transformation from Ce2O3 to CeO2 and also the formation of sulfides containing Cerium would experience the transformation from CeS to Ce2S3 and then to Ce3S4. Below 2000 K the most thermodynamic stable matter is CeO2 and the less thermodynamic stable inclusion is CeS. Only when the amount of [O] is extremely low and the amount of [S] and [Ce] is relatively high, Ce2S3 has the possibility to form.

  15. Evaluation of a Semiempirical, Zero-Dimensional, Multizone Model to Predict Nitric Oxide Emissions in DI Diesel Engines’ Combustion Chamber

    Directory of Open Access Journals (Sweden)

    Nicholas S. Savva

    2016-01-01

    Full Text Available In the present study, a semiempirical, zero-dimensional multizone model, developed by the authors, is implemented on two automotive diesel engines, a heavy-duty truck engine and a light-duty passenger car engine with pilot fuel injection, for various operating conditions including variation of power/speed, EGR rate, fuel injection timing, fuel injection pressure, and boost pressure, to verify its capability for Nitric Oxide (NO emission prediction. The model utilizes cylinder’s basic geometry and engine operating data and measured cylinder pressure to estimate the apparent combustion rate which is then discretized into burning zones according to the calculation step used. The requisite unburnt charge for the combustion in the zones is calculated using the zone equivalence ratio provided from a new empirical formula involving parameters derived from the processing of the measured cylinder pressure and typical engine operating parameters. For the calculation of NO formation, the extended Zeldovich mechanism is used. From this approach, the model is able to provide the evolution of NO formation inside each burned zone and, cumulatively, the cylinder’s NO formation history. As proven from the investigation conducted herein, the proposed model adequately predicts NO emissions and NO trends when the engine settings vary, with low computational cost. These encourage its use for engine control optimization regarding NOx abatement and real-time/model-based NOx control applications.

  16. Pulmonary exposure to particles from diesel exhaust, urban dust or single-walled carbon nanotubes and oxidatively damaged DNA and vascular function in apoE(-/-)mice

    DEFF Research Database (Denmark)

    Vesterdal, Lise K; Jantzen, Kim; Sheykhzade, Majid;

    2012-01-01

    Abstract This study compared the oxidative stress level and vasomotor dysfunction after exposure to urban dust, diesel exhaust particles (DEP) or single-walled carbon nanotubes (SWCNT). DEP and SWCNT increased the production of reactive oxygen species (ROS) in cultured endothelial cells......, Hmox-1 and Ogg1. The levels of oxidatively damaged DNA were unchanged in lung tissue. The exposure to SWCNT significantly increased the expression of Ccl-2 in the lung tissue of the mice. The exposure to DEP and SWCNT was associated with elevated ROS production in cultured cells, whereas intratracheal...

  17. Removal of Nox and Diesel Soot Particulates Catalyzed by Perovskite-type Oxide La0.9K0.1CoO3

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The catalytic performance of perovskite composite oxide catalyst La0.9 K0.1 CoO3 coated on catalyst supports by trnditional solid state reaction method and sol-gel method were investigated by a series of experiments.The result shows that the catalytic performance of the La0.9 K0.1 CoO3 perovskite composite oxide catalyst synthesized by sol-gel method is superior to that synthesized by solid state reaction method, having lower ignition tem-perature of the diesel soot particulates, lower start temperature of NO x treatment, and lower concentration of byproduct CO.

  18. Aerosol Physics Considerations for Using Cerium Oxide CeO2 as a Surrogate for Plutonium Oxide PuO2 in Airborne Release Fraction Measurements for Storage Container Investigations

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Murray E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tao, Yong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-16

    Cerium oxide (CeO2) dust is recommended as a surrogate for plutonium oxide (PuO2) in airborne release fraction experiments. The total range of applicable particle sizes for PuO2 extends from 0.0032 μm (the diameter of a single PuO2 molecule) to 10 μm (the defined upper boundary for respirable particles). For particulates with a physical particle diameter of 1.0 μm, the corresponding aerodynamic diameters for CeO2 and PuO2 are 2.7 μm and 3.4 μm, respectively. Cascade impactor air samplers are capable of measuring the size distributions of CeO2 or PuO2 particulates. In this document, the aerodynamic diameters for CeO2 and PuO2 were calculated for seven different physical diameters (0.0032, 0.02, 0.11, 0.27, 1.0, 3.2, and 10 μm). For cascade impactor measurements, CeO2 and PuO2 particulates with the same physical diameter would be collected onto the same or adjacent collection substrates. The difference between the aerodynamic diameter of CeO2 and PuO2 particles (that have the same physical diameter) is 39% of the resolution of a twelve-stage MSP Inc. 125 cascade impactor, and 34% for an eight-stage Andersen impactor. An approach is given to calculate the committed effective dose (CED) coefficient for PuO2 aerosol particles, compared to a corresponding aerodynamic diameter of CeO2 particles. With this approach, use of CeO2 as a surrogate for PuO2 material would follow a direct conversion based on a molar equivalent. In addition to the analytical information developed for this document, several US national labs have published articles about the use of CeO2 as a PuO2 surrogate. Different physical and chemical aspects were considered by these investigators, including thermal properties, ceramic formulations, cold pressing, sintering, molecular reactions, and mass loss in high temperature gas flows. All of those US national lab studies recommended the use of CeO2 as a surrogate material for PuO2.

  19. The influence of the nature of the metal on the performance of cerium oxide supported catalysts in the partial oxidation of ethanol

    Science.gov (United States)

    Mattos, L. V.; Noronha, F. B.

    This work studied the effect of the nature of the metal on the performance of Co/CeO 2, Pd/CeO 2 and Pt/CeO 2 catalysts in the partial oxidation of ethanol. Infrared spectroscopy of adsorbed ethanol and temperature programmed desorption of ethanol were performed in order to establish the reaction mechanism. Catalytic experiments revealed that the product distribution is strongly affected by the nature of the metal. Acetaldehyde was practically the only product formed on a Co/CeO 2 catalyst while methane was also produced on Pt/CeO 2 and Pd/CeO 2 catalysts. These results were explained through a reaction mechanism proposed by the characterization techniques. Co/CeO 2 and Pt/CeO 2 catalysts show mainly ethoxy species at room temperature whereas acetate species is mainly formed on the Pd/CeO 2 catalyst. The ethoxy species can undergo further dehydrogenation and desorb as acetaldehyde. This effect is more significant with the Co/CeO 2 catalyst and could explain the higher selectivity to acetaldehyde observed on supported Co and Pt catalysts.

  20. Influence of EGR compounds on the oxidation of an HCCI-diesel surrogate

    CERN Document Server

    Anderlohr, Jörg; Da Cruz, A Pires; Bounaceur, Roda; Battin-Leclerc, Frédérique; Dagaut, Philippe; Montagne, X; 10.1016/j.proci.2008.06.019

    2009-01-01

    This paper presents an experimental and numerical study of the impact of various additives on the oxidation of a typical automotive surrogate fuel blend, i.e. n-heptane and toluene. It examines the impact of engine re-cycled exhaust has compounds on the control of an Homogeneous Charge Compression-Ignition (HCCI) engine. Series of experiments were performed in a hihly diluted Jet-Stirred Reactor (JDR) at pressures of 1 and 10 atm (1 atm = 101,325 Pa). The chosen thermo-chemical conditions were close to those characteristices of the pre-ignition period in an HCCI engine. The influence of various additives, namely nitric oxide (NO), ethylene (C2H4) and methanol (CH3OH), on the oxidation of a n-heptane/toluene blend was studied over a wide range of temperatures (550-1100 K), including the zone of the Negative Temperature Coefficient (NTC).

  1. Improvement of engine emissions with conventional diesel fuel and diesel-biodiesel blends.

    Science.gov (United States)

    Nabi, Md Nurun; Akhter, Md Shamim; Zaglul Shahadat, Mhia Md

    2006-02-01

    In this report combustion and exhaust emissions with neat diesel fuel and diesel-biodiesel blends have been investigated. In the investigation, firstly biodiesel from non-edible neem oil has been made by esterification. Biodiesel fuel (BDF) is chemically known as mono-alkyl fatty acid ester. It is renewable in nature and is derived from plant oils including vegetable oils. BDF is non-toxic, biodegradable, recycled resource and essentially free from sulfur and carcinogenic benzene. In the second phase of this investigation, experiment has been conducted with neat diesel fuel and diesel-biodiesel blends in a four stroke naturally aspirated (NA) direct injection (DI) diesel engine. Compared with conventional diesel fuel, diesel-biodiesel blends showed lower carbon monoxide (CO), and smoke emissions but higher oxides of nitrogen (NOx) emission. However, compared with the diesel fuel, NOx emission with diesel-biodiesel blends was slightly reduced when EGR was applied.

  2. Mutagenicity of diesel engine exhaust is eliminated in the gas phase by an oxidation catalyst but only slightly reduced in the particle phase.

    Science.gov (United States)

    Westphal, Götz A; Krahl, Jürgen; Munack, Axel; Ruschel, Yvonne; Schröder, Olaf; Hallier, Ernst; Brüning, Thomas; Bünger, Jürgen

    2012-06-05

    Concerns about adverse health effects of diesel engine emissions prompted strong efforts to minimize this hazard, including exhaust treatment by diesel oxidation catalysts (DOC). The effectiveness of such measures is usually assessed by the analysis of the legally regulated exhaust components. In recent years additional analytical and toxicological tests were included in the test panel with the aim to fill possible analytical gaps, for example, mutagenic potency of polycyclic aromatic hydrocarbons (PAH) and their nitrated derivatives (nPAH). This investigation focuses on the effect of a DOC on health hazards from combustion of four different fuels: rapeseed methyl ester (RME), common mineral diesel fuel (DF), SHELL V-Power Diesel (V-Power), and ARAL Ultimate Diesel containing 5% RME (B5ULT). We applied the European Stationary Cycle (ESC) to a 6.4 L turbo-charged heavy load engine fulfilling the EURO III standard. The engine was operated with and without DOC. Besides regulated emissions we measured particle size and number distributions, determined the soluble and solid fractions of the particles and characterized the bacterial mutagenicity in the gas phase and the particles of the exhaust. The effectiveness of the DOC differed strongly in regard to the different exhaust constituents: Total hydrocarbons were reduced up to 90% and carbon monoxide up to 98%, whereas nitrogen oxides (NO(X)) remained almost unaffected. Total particle mass (TPM) was reduced by 50% with DOC in common petrol diesel fuel and by 30% in the other fuels. This effect was mainly due to a reduction of the soluble organic particle fraction. The DOC caused an increase of the water-soluble fraction in the exhaust of RME, V-Power, and B5ULT, as well as a pronounced increase of nitrate in all exhausts. A high proportion of ultrafine particles (10-30 nm) in RME exhaust could be ascribed to vaporizable particles. Mutagenicity of the exhaust was low compared to previous investigations. The DOC reduced

  3. Study of the catalytic activity of pure or cerium-containing thoria in the catalytic oxidation of carbon monoxide (1963); Etude de l'activite catalytique de la thorine pure ou contenant du cerium. Dans l'oxydation de l'oxyde de carbone (1963)

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-07-01

    We have undertaken research into the oxidation of carbon monoxide on pure thoria prepared by the decomposition of thorium nitrate, and on the same oxide containing small amounts of cerium. The results we have obtained, both as concerns the chemisorption of the various gases as well as the conductivity of the absorbent and the kinetics of the oxidation itself, appear to be quite coherent. The following steps occur: 1) The carbon monoxide is adsorbed on a clean catalyst surface, the oxygen remaining un-adsorbed. 2) The oxygen is adsorbed on a previously adsorbed carbon, monoxide layer, and reacts to give carbon dioxide (no role being played by the lattice oxygen). This behaviour is usual for a p-type semiconductor. We have in fact confirmed that semi-conductivity is of this type, and the gas-solid interactions can be written: (1) CO{sub (g)} {r_reversible} CO{sup +}{sub (a)} + e{sup -} (2) CO{sup +} 1/2 O{sub 2(g)} + 2 e{sup -} {yields} CO{sup -}{sub 2(a)} (3) CO{sup -}{sub 2(a)} {r_reversible} CO{sub 2(g)} + e{sup -} The kinetic equation obtained by supposing that step (2) is the slowest, makes it possible to deduce correctly the experimental results which can be expressed as: dp / dt = k (P{sup 0.3}{sub CO} x P{sup 0.5}{sub O{sub 2}}) / (1+ k' x P{sub CO{sub 2}}) The influence of the addition of small amounts of cerium can also be explained logically by this process; there is in fact both a decrease in the conductivity and an increase in the catalytic activity, this being characteristic, according to VOLKENSTEIN [52] of an n-type rate-determining reaction occurring on a p-type semi-conductor. We believe that these first results could be advantageously complemented by a study of thoria prepared by other means and doped differently. (author) [French] Nous avons entrepris l'etude de l'oxydation de l'oxyde de carbone sur la thorine pure preparee par decomposition du nitrate de thorium, et sur le meme oxyde renfermant de petites quantites de cerium

  4. Titrimetric and Spectrophotometric Methods for the Assay of Ketotifen Using Cerium(IV) and Two Reagents

    OpenAIRE

    Madihalli Srinivas Raghu; Kanakapura Basavaiah; Kudige Nagaraj Prashanth; Kanakapura Basavaiah Vinay

    2013-01-01

    One titrimetric and two spectrophotometric methods are described for the determination of ketotifen fumarate (KTF) in bulk drug and in tablets using cerium(IV) as the oxidimetric agent. In titrimetry (method A), the drug was treated with a measured excess of cerium(IV) in H2SO4 medium and after a standing time of 10 min, the surplus oxidant was determined by back titration with iron(II). The spectrophotometric procedures involve addition of a known excess of cerium(IV) to KTF in acid medium f...

  5. Purification of cerium, neodymium and gadolinium for low background experiments

    Directory of Open Access Journals (Sweden)

    Boiko R.S.

    2014-01-01

    Full Text Available Cerium, neodymium and gadolinium contain double beta active isotopes. The most interesting are 150Nd and 160Gd (promising for 0ν2β search, 136Ce (2β+ candidate with one of the highest Q2β. The main problem of compounds containing lanthanide elements is their high radioactive contamination by uranium, radium, actinium and thorium. The new generation 2β experiments require development of methods for a deep purification of lanthanides from the radioactive elements. A combination of physical and chemical methods was applied to purify cerium, neodymium and gadolinium. Liquid-liquid extraction technique was used to remove traces of Th and U from neodymium, gadolinium and for purification of cerium from Th, U, Ra and K. Co-precipitation and recrystallization methods were utilized for further reduction of the impurities. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe gamma spectrometry. As a result of the purification procedure the radioactive contamination of gadolinium oxide (a similar purification efficiency was reached also with cerium and neodymium oxides was decreased from 0.12 Bq/kg to 0.007 Bq/kg in 228Th, from 0.04 Bq/kg to <0.006 Bq/kg in 226Ra, and from 0.9 Bq/kg to 0.04 Bq/kg in 40K. The purification methods are much less efficient for chemically very similar radioactive elements like actinium, lanthanum and lutetium.

  6. L-proline-based deep eutectic solvents (DESs) for deep catalytic oxidative desulfurization (ODS) of diesel.

    Science.gov (United States)

    Hao, Lingwan; Wang, Meiri; Shan, Wenjuan; Deng, Changliang; Ren, Wanzhong; Shi, Zhouzhou; Lü, Hongying

    2017-10-05

    A series of L-proline-based DESs was prepared through an atom economic reaction between L-proline (L-Pro) and four different kinds of organic acids. The DESs were characterized by Fourier transform infrared spectroscopy (FT-IR), H nuclear magnetic resonance ((1)HNMR), cyclic voltammogram (CV) and the Hammett method. The synthesized DESs were used for the oxidative desulfurization and the L-Pro/p-toluenesultonic acid (L-Pro/p-TsOH) system shows the highest catalytic activity that the removal of dibenzothiophene (DBT) reached 99% at 60°C in 2h, which may involve the dual activation of the L-Pro/p-TsOH. The acidity of four different L-proline-based DESs was measured and the results show that it could not simply conclude that the correlation between the acidity of DESs and desulfurization capability was positive or negative. The electrochemical measurements evidences and recycling experiment indicate a good stability performance of L-Pro/p-TsOH in desulfurization. This work will provide a novel and potential method for the deep oxidation desulfurization. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Gaseous nitrous acid (HONO) and nitrogen oxides (NOx) emission from gasoline and diesel vehicles under real-world driving test cycles.

    Science.gov (United States)

    Trinh, Ha T; Imanishi, Katsuma; Morikawa, Tazuko; Hagino, Hiroyuki; Takenaka, Norimichi

    2017-04-01

    Reactive nitrogen species emission from the exhausts of gasoline and diesel vehicles, including nitrogen oxides (NOx) and nitrous acid (HONO), contributes as a significant source of photochemical oxidant precursors in the ambient air. Multiple laboratory and on-road exhaust measurements have been performed to estimate the NOx emission factors from various vehicles and their contribution to atmospheric pollution. Meanwhile, HONO emission from vehicle exhaust has been under-measured despite the fact that HONO can contribute up to 60% of the total hydroxyl budget during daytime and its formation pathway is not fully understood. A profound traffic-induced HONO to NOx ratio of 0.8%, established by Kurtenbach et al. since 2001, has been widely applied in various simulation studies and possibly linked to under-estimation of HONO mixing ratios and OH radical budget in the morning. The HONO/NOx ratios from direct traffic emission have become debatable when it lacks measurements for direct HONO emission from vehicles upon the fast-changing emission reduction technology. Several recent studies have reported updated values for this ratio. This study has reported the measurement of HONO and NOx emission as well as the estimation of exhaust-induced HONO/NOx ratios from gasoline and diesel vehicles using different chassis dynamometer tests under various real-world driving cycles. For the tested gasoline vehicle, which was equipped with three-way catalyst after-treatment device, HONO/NOx ratios ranged from 0 to 0.95 % with very low average HONO concentrations. For the tested diesel vehicle equipped with diesel particulate active reduction device, HONO/NOx ratios varied from 0.16 to 1.00 %. The HONO/NOx ratios in diesel exhaust were inversely proportional to the average speeds of the tested vehicles. Photolysis of HONO is a dominant source of morning OH radicals. Conventional traffic-induced HONO/NOx ratio of 0.8% has possibly linked to underestimation of the total HONO budget and

  8. Effects of cerium dioxide nanoparticles in Oncorhynchus mykiss gills after an acute exposure: assessment of oxidative stress, genotoxicity and histological alterations

    Directory of Open Access Journals (Sweden)

    Alberto Teodorico Correia

    2015-12-01

    Full Text Available Data about the toxicological effects of cerium dioxide nanoparticles (CeO2 NP in fish are scarce. This work aimed to assess the CeO2 NP possible deleterious effects on the gills of Oncorhynchus mykiss. A semi-continuous acute test was conducted to expose the rainbow trout to a freshwater control, 0.25, 2.50 and 25.00 mg/L CeO2 NPs for up to 96 hours. Gills pathological index showed a dose-effect relationship for the individuals exposed to CeO2. Gills showed aneurisms, epithelial lifting and hyperplasia. Furthermore exposure to CeO2 NPs caused statistical differences in some biomarkers determinations, namely a significant increase in the catalase activity and genotoxicity the higher concentrations. No significant changes were however observed in thiobarbituric acid reactive substances content, Na+-K+ ATPase and glutathione s-transferase activities. This study suggests that CeO2 nanoparticles are toxic compounds that can lead to histological, biochemical and genotoxic alterations.

  9. Session 4: The Mo/Al{sub 2}O{sub 3}-H{sub 2}O{sub 2} a catalytic system for the obtention of ultra low sulfur diesel by oxidative desulfurization process

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Gutierrez, J.L.; Jimenez Cruz, F.; Atocha Hernandez Cortazar, F. de; Cano Dominguez, J.L.; Ramirez Verduzco, L.F.; Murrieta Guevara, F.R. [Programa de Tratamiento de Crudo Maya. Instituto Mexicano del Petroleo Eje Central Lazaro Cardenas 152, D. F. (Mexico)

    2004-07-01

    At present the production of transportation fuels free of polluting compounds is a matter of consequence worldwide. Particularly, sulfur compounds are undesirable in gasoline and diesel because they contribute to air pollution and acid rain. In this work, we present the results obtained in the development of some supported catalysts containing molybdenum and its evaluation in the desulfurization of several model sulfur systems and diesel by the oxidation-extraction process using hydrogen peroxide with the aim of produce ultra low sulfur diesel. The molybdenum catalysts were prepared by the equilibrium adsorption method. The oxidizing reagent was hydrogen peroxide (30 wt % solution in water) and the fuel was a Mexican diesel with 0.0320 wt % sulfur. The sulfur concentration in the samples was measured by a total sulfur analyzer equipped with a X-ray fluorescence detector, the accuracy is {+-} 5 %. The oxidation-extraction process of diesel was carried out in a batch reactor in presence of hydrogen peroxide, a solvent and the catalyst. The oxidation proceeds under mild conditions: temperature less than 373 K and atmospheric pressure. Oxidized sulfur compounds were separated from the diesel by extraction with the same solvent used in the oxidation process. The effect of the reaction variables, e. g.: time, temperature, hydrogen peroxide concentration, solvent and its concentration, molybdenum precursor, support, the stability of the catalytic activity, structure of the model sulfur compounds, were examined. The results show that the catalyst activity depends on the isoelectric point of the support. It was observed that the oxidation was carried out with good yield only in the presence of a polar solvent. A linear dependence was found between the electric density of the sulfur atom for the organosulfur compounds and its oxidation facility with the oxidation system in matter. This is in good agreement with the work reported by Otsuki. In the oxidation of diesel, it was

  10. PLUTONIUM-CERIUM-COBALT AND PLUTONIUM-CERIUM-NICKEL ALLOYS

    Science.gov (United States)

    Coffinberry, A.S.

    1959-08-25

    >New plutonium-base teroary alloys useful as liquid reactor fuels are described. The alloys consist of 10 to 20 atomic percent cobalt with the remainder plutonium and cerium in any desired proportion, with the plutonium not in excess of 88 atomic percent; or, of from 10 to 25 atomic percent nickel (or mixture of nickel and cobalt) with the remainder plutonium and cerium in any desired proportion, with the plutonium not in excess of 86 atomic percent. The stated advantages of these alloys over unalloyed plutonium for reactor fuel use are a lower melting point and a wide range of permissible plutonium dilution.

  11. High-permitivity cerium oxide prepared by molecular beam deposition as gate dielectric and passivation layer and applied to AlGaN/GaN power high electron mobility transistor devices

    Science.gov (United States)

    Chiu, Yu Sheng; Liao, Jen Ting; Lin, Yueh Chin; Chien Liu, Shin; Lin, Tai Ming; Iwai, Hiroshi; Kakushima, Kuniyuki; Chang, Edward Yi

    2016-05-01

    High-κ cerium oxide (CeO2) was applied to AlGaN/GaN high-electron-mobility transistors (HEMTs) as a gate insulator and a passivation layer by molecular beam deposition (MBD) for high-power applications. From capacitance-voltage (C-V) measurement results, the dielectric constant of the CeO2 film was 25.2. The C-V curves showed clear accumulation and depletion behaviors with a small hysteresis (20 mV). Moreover, the interface trap density (D it) was calculated to be 5.5 × 1011 eV-1 cm-2 at 150 °C. A CeO2 MOS-HEMT was fabricated and demonstrated a low subthreshold swing (SS) of 87 mV/decade, a high ON/OFF drain current ratio (I ON/I OFF) of 1.14 × 109, and a low gate leakage current density (J leakage) of 2.85 × 10-9 A cm-2 with an improved dynamic ON-resistance (R ON), which is about one order of magnitude lower than that of a conventional HEMT.

  12. Catalysts with Cerium in a Membrane Reactor for the Removal of Formaldehyde Pollutant from Water Effluents.

    Science.gov (United States)

    Gutiérrez-Arzaluz, Mirella; Noreña-Franco, Luis; Ángel-Cuevas, Saúl; Mugica-Álvarez, Violeta; Torres-Rodríguez, Miguel

    2016-05-24

    We report the synthesis of cerium oxide, cobalt oxide, mixed cerium, and cobalt oxides and a Ce-Co/Al₂O₃ membrane, which are employed as catalysts for the catalytic wet oxidation (CWO) reaction process and the removal of formaldehyde from industrial effluents. Formaldehyde is present in numerous waste streams from the chemical industry in a concentration low enough to make its recovery not economically justified but high enough to create an environmental hazard. Common biological degradation methods do not work for formaldehyde, a highly toxic but refractory, low biodegradability substance. The CWO reaction is a recent, promising alternative that also permits much lower temperature and pressure conditions than other oxidation processes, resulting in economic benefits. The CWO reaction employing Ce- and Co-containing catalysts was carried out inside a slurry batch reactor and a membrane reactor. Experimental results are reported. Next, a mixed Ce-Co oxide film was supported on an γ-alumina membrane used in a catalytic membrane reactor to compare formaldehyde removal between both types of systems. Catalytic materials with cerium and with a relatively large amount of cerium favored the transformation of formaldehyde. Cerium was present as cerianite in the catalytic materials, as indicated by X-ray diffraction patterns.

  13. Catalysts with Cerium in a Membrane Reactor for the Removal of Formaldehyde Pollutant from Water Effluents

    Directory of Open Access Journals (Sweden)

    Mirella Gutiérrez-Arzaluz

    2016-05-01

    Full Text Available We report the synthesis of cerium oxide, cobalt oxide, mixed cerium, and cobalt oxides and a Ce–Co/Al2O3 membrane, which are employed as catalysts for the catalytic wet oxidation (CWO reaction process and the removal of formaldehyde from industrial effluents. Formaldehyde is present in numerous waste streams from the chemical industry in a concentration low enough to make its recovery not economically justified but high enough to create an environmental hazard. Common biological degradation methods do not work for formaldehyde, a highly toxic but refractory, low biodegradability substance. The CWO reaction is a recent, promising alternative that also permits much lower temperature and pressure conditions than other oxidation processes, resulting in economic benefits. The CWO reaction employing Ce- and Co-containing catalysts was carried out inside a slurry batch reactor and a membrane reactor. Experimental results are reported. Next, a mixed Ce–Co oxide film was supported on an γ-alumina membrane used in a catalytic membrane reactor to compare formaldehyde removal between both types of systems. Catalytic materials with cerium and with a relatively large amount of cerium favored the transformation of formaldehyde. Cerium was present as cerianite in the catalytic materials, as indicated by X-ray diffraction patterns.

  14. Cerium, manganese and cerium/manganese ceramic monolithic catalysts. Study of VOCs and PM removal

    Institute of Scientific and Technical Information of China (English)

    COLMAN-LERNER Esteban; PELUSO Miguel Andrs; SAMBETH Jorge; THOMAS Horacio

    2016-01-01

    Ceramic supported cerium, manganese and cerium-manganese catalysts were prepared by direct impregnation of aqueous precursor, and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller method (BET), temperature programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS) acidity measurements and electrical conductivity. The catalytic activity was evaluated for volatile organic compounds (VOC) (ethanol, methyl ethyl ketone and toluene) oxidation. Additionally, catalysts were tested in particulate matter (PM) combustion. The characterization results indicated that Ce was in the form of Ce4+ and Ce3+, and Mn existed in the form of Mn4+and Mn3+on the surface of the Mn/AC sample and in the form of Mn4+ in the Ce/Mn/AC monolith. VOC oxidation results revealed that the Ce/Mn/AC sample showed an excellent performance compared with ceramic supported CeO2 (Ce/AC) and MnOx (Mn/AC) samples. The PM combustion was also higher on Ce/Mn/AC monoliths. The enhanced catalytic activity was mainly attributed to the Ce and Mn interaction which enhanced the acidity, conductiv-ity and the reducibility of the oxides.

  15. Differential Responses upon Inhalation Exposure to Biodiesel versus Diesel Exhaust on Oxidative Stress, Inflammatory and Immune Outcomes

    Science.gov (United States)

    Biodiesel (BD) exhaust may have reduced adverse health effects due to lower mass emissions and reduced production of hazardous compounds compared to diesel exhaust. To investigate this possibility, we compared adverse effects in lungs and liver of BALB/cJ mice after inhalation ex...

  16. Reduction of nitric oxide emissions of stationary diesel engines with SCR and urea as reduction agents. Stickstoffoxidminderung bei stationaeren Dieselmotoren mittels SCR und Harnstoff als Reduktionsmittel

    Energy Technology Data Exchange (ETDEWEB)

    Koebel, M.; Elsener, M.; Eicher, H.P.

    1991-03-01

    Experiments were carried out to determine whether urea can replace ammonia in the selective catalytic reduction of nitric oxides. Pyrolysis experiments with aqueous urea solutions showed that it depended on the conditions of decomposition whether ammonia or urea was produced in changing quantities. Like pure ammonia the pyrolysis-gas mixture can be used in SCR catalytic converters with nitric oxides. Experiments with the exhaust gas of a diesel engine showed that the method also works in practice and is basically ready for application. Successfull application on a wider basis however can only start after overcoming the difficult technical problems of administering the reduction agent, process control, intermitting operation and service life of catalytic converter. (orig.).

  17. Investigation of process variables and intensification effects of ultrasound applied in oxidative desulfurization of model diesel over MoO3/Al2O3 catalyst.

    Science.gov (United States)

    Akbari, Azam; Omidkhah, Mohammadreza; Darian, Jafar Towfighi

    2014-03-01

    A new heterogeneous sonocatalytic system consisting of a MoO3/Al2O3 catalyst and H2O2 combined with ultrasonication was studied to improve and accelerate the oxidation of model sulfur compounds of diesel, resulting in a significant enhancement in the process efficiency. The influence of ultrasound on properties, activity and stability of the catalyst was studied in detail by means of GC-FID, PSD, SEM and BET techniques. Above 98% conversion of DBT in model diesel containing 1000 μg/g sulfur was obtained by new ultrasound-assisted desulfurization at H2O2/sulfur molar ratio of 3, temperature of 318 K and catalyst dosage of 30 g/L after 30 min reaction, contrary to the 55% conversion obtained during the silent process. This improvement was considerably affected by operation parameters and catalyst properties. The effects of main process variables were investigated using response surface methodology in silent process compared to ultrasonication. Ultrasound provided a good dispersion of catalyst and oxidant by breakage of hydrogen bonding and deagglomeration of them in the oil phase. Deposition of impurities on the catalyst surface caused a quick deactivation in silent experiments resulting only 5% of DBT oxidation after 6 cycles of silent reaction by recycled catalyst. Above 95% of DBT was oxidized after 6 ultrasound-assisted cycles showing a great improvement in stability by cleaning the surface during ultrasonication. A considerable particle size reduction was also observed after 3 h sonication that could provide more dispersion of catalyst in model fuel.

  18. Performance of diesel engine using diesel B3 mixed with crude palm oil.

    Science.gov (United States)

    Namliwan, Nattapong; Wongwuttanasatian, Tanakorn

    2014-01-01

    The objective of this study was to test the performance of diesel engine using diesel B3 mixed with crude palm oil in ratios of 95 : 5, 90 : 10, and 85 : 15, respectively, and to compare the results with diesel B3. According to the tests, they showed that the physical properties of the mixed fuel in the ratio of 95 : 5 were closest to those of diesel B3. The performance of the diesel engine that used mixed fuels had 5-17% lower torque and power than that of diesel B3. The specific fuel consumption of mixed fuels was 7-33% higher than using diesel B3. The components of gas emissions by using mixed fuel had 1.6-52% fewer amount of carbon monoxide (CO), carbon dioxide (CO2), sulfur dioxide (SO2), and oxygen (O2) than those of diesel B3. On the other hand, nitric oxide (NO) and nitrogen oxides (NO X ) emissions when using mixed fuels were 10-39% higher than diesel B3. By comparing the physical properties, the performance of the engine, and the amount of gas emissions of mixed fuel, we found out that the 95 : 5 ratio by volume was a suitable ratio for agricultural diesel engine (low-speed diesel engine).

  19. Performance of Diesel Engine Using Diesel B3 Mixed with Crude Palm Oil

    Directory of Open Access Journals (Sweden)

    Nattapong Namliwan

    2014-01-01

    Full Text Available The objective of this study was to test the performance of diesel engine using diesel B3 mixed with crude palm oil in ratios of 95 : 5, 90 : 10, and 85 : 15, respectively, and to compare the results with diesel B3. According to the tests, they showed that the physical properties of the mixed fuel in the ratio of 95 : 5 were closest to those of diesel B3. The performance of the diesel engine that used mixed fuels had 5–17% lower torque and power than that of diesel B3. The specific fuel consumption of mixed fuels was 7–33% higher than using diesel B3. The components of gas emissions by using mixed fuel had 1.6–52% fewer amount of carbon monoxide (CO, carbon dioxide (CO2, sulfur dioxide (SO2, and oxygen (O2 than those of diesel B3. On the other hand, nitric oxide (NO and nitrogen oxides (NOX emissions when using mixed fuels were 10–39% higher than diesel B3. By comparing the physical properties, the performance of the engine, and the amount of gas emissions of mixed fuel, we found out that the 95 : 5 ratio by volume was a suitable ratio for agricultural diesel engine (low-speed diesel engine.

  20. The impact of carbon dioxide and exhaust gas recirculation on the oxidative reactivity of soot from ethylene flames and diesel engines

    Science.gov (United States)

    Al-Qurashi, Khalid O.

    Restrictive emissions standards to reduce nitrogen oxides (NOx) and particulate matter (PM) emissions from diesel engines necessitate the development of advanced emission control technology. The engine manufacturers in the United States have implemented the exhaust gas recirculation (EGR) and diesel particulate filters (DPF) to meet the stringent emissions limits on NOx and PM, respectively. Although the EGR-DPF system is an effective means to control diesel engine emissions, there are some concerns associated with its implementation. The chief concern with this system is the DPF regenerability, which depends upon several factors, among which are the physicochemical properties of the soot. Despite the plethora of research that has been conducted on DPF regenerability, the impact of EGR on soot reactivity and DPF regenerability is yet to be examined. This work concerns the impact of EGR on the oxidative reactivity of diesel soot. It is part of ongoing research to bridge the gap in establishing a relationship between soot formation conditions, properties, and reactivity. This work is divided into three phases. In the first phase, carbon dioxide (CO2) was added to the intake charge of a single cylinder engine via cylinders of compressed CO2. This approach simulates the cold-particle-free EGR. The results showed that inclusion of CO2 changes the soot properties and yields synergistic effects on the oxidative reactivity of the resulting soot. The second phase of this research was motivated by the findings from the first phase. In this phase, post-flame ethylene soot was produced from a laboratory co-flow laminar diffusion flame to better understand the mechanism by which the CO2 affects soot reactivity. This phase was accomplished by successfully isolating the dilution, thermal, and chemical effects of the CO2. The results showed that all of these effects account for a measurable increase in soot reactivity. Nevertheless, the thermal effect was found to be the most

  1. Deep Oxidative Desulfurization of Dibenzothiophene in Simulated Oil and Real Diesel Using Heteropolyanion-Substituted Hydrotalcite-Like Compounds as Catalysts

    Directory of Open Access Journals (Sweden)

    Rui Wang

    2013-11-01

    Full Text Available Three heteropolyanion substituted hydrotalcite-like compounds (HPA-HTLcs including Mg9Al3(OH24[PW12O40](MgAl-PW12, Mg9Al3(OH24[PMo12O40] (MgAl-PMo12 and Mg12Al4(OH32[SiW12O40] (MgAl-SiW12, were synthesized, characterized and used as catalysts for the oxidative desulfurization of simulated oil (dibenzothiophene, DBT, in n-octane. MgAl-PMo12 was identified as an effective catalyst for the oxidative removal of DBT under very mild conditions of atmospheric pressure and 60 °C in a biphasic system using hydrogen peroxide as oxidant and acetonitrile as extractant. The conversion of DBT was nearly 100%. As a result, because of the influence of the electron density and the space steric hindrance, the oxidation reactivity of the different sulfur compounds in simulated oil followed the order DBT > 4,6-dimethyldibenzothiophene (4,6-DMDBT > benzothiophene (BT > thiophene (TH. When the reaction is finished, the catalysts can be recovered from the acetonitrile phase by filtration. The recovered MgAl-PMo12 retains nearly the same catalytic activity as the fresh material. Moreover, MgAl-PMo12 was found to exhibit an ideal catalytic activity in the oxidative desulfurization of real diesel resulting in a total remaining sulfur content of 9.12 ppm(w.

  2. Deep oxidative desulfurization of dibenzothiophene in simulated oil and real diesel using heteropolyanion-substituted hydrotalcite-like compounds as catalysts.

    Science.gov (United States)

    Yu, Fengli; Wang, Rui

    2013-11-05

    Three heteropolyanion substituted hydrotalcite-like compounds (HPA-HTLcs) including Mg₉Al₃(OH)₂₄[PW₁₂O₄₀](MgAl-PW₁₂), Mg₉Al₃(OH)₂₄[PMo₁₂O₄₀] (MgAl-PMo₁₂) and Mg₁₂Al₄(OH)₃₂[SiW₁₂O₄₀] (MgAl-SiW₁₂), were synthesized, characterized and used as catalysts for the oxidative desulfurization of simulated oil (dibenzothiophene, DBT, in n-octane). MgAl-PMo₁₂ was identified as an effective catalyst for the oxidative removal of DBT under very mild conditions of atmospheric pressure and 60 °C in a biphasic system using hydrogen peroxide as oxidant and acetonitrile as extractant. The conversion of DBT was nearly 100%. As a result, because of the influence of the electron density and the space steric hindrance, the oxidation reactivity of the different sulfur compounds in simulated oil followed the order DBT > 4,6-dimethyldibenzothiophene (4,6-DMDBT) > benzothiophene (BT) > thiophene (TH). When the reaction is finished, the catalysts can be recovered from the acetonitrile phase by filtration. The recovered MgAl-PMo₁₂ retains nearly the same catalytic activity as the fresh material. Moreover, MgAl-PMo₁₂ was found to exhibit an ideal catalytic activity in the oxidative desulfurization of real diesel resulting in a total remaining sulfur content of 9.12 ppm(w).

  3. Anode regeneration following carbon depositions in an industrial-sized anode supported solid oxide fuel cell operating on synthetic diesel reformate

    Science.gov (United States)

    Subotić, Vanja; Schluckner, Christoph; Mathe, Jörg; Rechberger, Jürgen; Schroettner, Hartmuth; Hochenauer, Christoph

    2015-11-01

    Carbon deposition is a primary concern during operation of solid oxide fuel cells (SOFCs) fueled with carbon-containing fuels. It leads to cell degradation and thus reduces SOFC sustained operation and durability. This paper reports on an experimental investigation of carbon formation on the nickel/yttria-stabilized zirconia (Ni/YSZ) anode of an anode-supported SOFC and its regeneration. The cell was fueled with a synthetically produced diesel reformate to investigate and simulate the cell behavior under real operating conditions. For this purpose the cell was operated under load to determine the critical operating time. Rapid carbon generation, such as at open circuit voltage (OCV), can be prevented when the cell is under load. Carbon depositions were detected using scanning electron microscopy (SEM) and further analyzed by Raman spectroscopy. Industrial-size cells suitable for commercial applications were studied. This study proves the reversibility of carbon formation and the reproducibility of the regeneration process. It shows that carbon formations can be recognized and effectively, fully and cell-protecting regenerated. It indicates the excellent possibility of using SOFCs in the automotive industry as an auxiliary power unit (APU) or combined power-heat unit, operated with diesel reformate, without danger from cell degradation caused by carbon-containing fuels.

  4. Bioremediation of diesel-polluted soil using biostimulation as post-treatment after oxidation with Fenton-like reagents: assays in a pilot plant.

    Science.gov (United States)

    Silva-Castro, Gloria Andrea; Rodelas, Belén; Perucha, Carlos; Laguna, Jaime; González-López, Jesús; Calvo, Concepción

    2013-02-15

    The present study focuses on the remediation of diesel-polluted soil using modified Fenton treatment coupled with inorganic NPK fertilizer ("Fenton+NPK"). Studies were carried out in a pilot plant containing 1 m(3) of sandy soil contaminated with 20,000 mg kg(-1) of diesel, placed outdoors at a temperature ranging between 5 and 10 °C. Results showed that NPK-fertilizer as post-treatment stimulated culturable degrading bacteria and enhanced dehydrogenase activity. Fenton+NPK treatment increased total petroleum hydrocarbon (TPH) removal efficacy. Natural attenuation removed 49% of TPH in the surface layer, 23% of TPH in the non-saturated layer and 4% of the TPH in the saturated layer, while the percentage removed of TPH after Fenton+NPK treatment was 58%, 57% and 32% respectively. The results from our study showed that, immediately after soil contamination, occurred a specialization and differentiation of the bacterial community, but after this initial modification, no significant changes of bacterial diversity was observed under natural attenuation conditions. In contrast, when the Fenton's reagent was applied a reduction of the bacterial biodiversity was observed. However, the post-biostimulation did enhance the degrading microbiota and stimulated their degrading biological activity. In conclusion, biostimulation, as a post-treatment step in chemical oxidation, is an effective solution to remediate hydrocarbon-polluted sites.

  5. Oxidation of alginate and pectate biopolymers by cerium(IV) in perchloric and sulfuric acid solutions: A comparative kinetic and mechanistic study.

    Science.gov (United States)

    Fawzy, Ahmed

    2016-03-15

    The kinetics of oxidation of alginate (Alg) and pectate (Pec) carbohydrate biopolymers was studied by spectrophotometry in aqueous perchloric and sulfuric acid solutions at fixed ionic strengths and temperature. In both acids, the reactions showed a first order dependence on [Ce(IV)], whereas the orders with respect to biopolymer concentrations are less than unity. In perchloric acid, the reactions exhibited less than unit orders with respect to [H(+)] whereas those proceeded in sulfuric acid showed negative fractional-first order dependences on [H(+)]. The effect of ionic strength and dielectric constant was studied. Probable mechanistic schemes for oxidation reactions were proposed. In both acids, the final oxidation products were characterized as mono-keto derivatives of both biopolymers. The activation parameters with respect to the slow step of the mechanisms were computed and discussed. The rate laws were derived and the reaction constants involved in the different steps of the mechanisms were calculated.

  6. Adsorption of Fluoride Ion by Inorganic Cerium Based Adsorbent

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

  7. DNA adduct formation and oxidative stress in colon and liver of Big Blue (R) rats after dietary exposure to diesel particles

    DEFF Research Database (Denmark)

    Dybdahl, M.; Risom, L.; Møller, P.

    2003-01-01

    Exposure to diesel exhaust particles (DEP) via the gastrointestinal route may impose risk of cancer in the colon and liver. We investigated the effects of DEP given in the diet to Big Blue(R) rats by quantifying a panel of markers of DNA damage and repair, mutation, oxidative damage to proteins...... and lipids, and antioxidative defence mechanisms in colon mucosa cells, liver tissue and the blood compartment. Seven groups of rats were fed a diet with 0, 0.2, 0.8, 2, 8, 20 or 80 mg DEP/kg feed for 21 days. DEP induced a significant increase in DNA strand breaks in colon and liver. There was no effect...

  8. Diesel/biodiesel soot oxidation with CeO{sub 2} and CeO{sub 2}-ZrO{sub 2}- modified cordierites: a facile way of accounting for their catalytic ability in fuel combustion processes

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Rodrigo F.; Oliveira, Edimar de; Sousa Filho, Paulo C. de; Neri, Claudio R.; Serra, Osvaldo A., E-mail: crneri@usp.b [Universidade de Sao Paulo (DQ/FFCLRP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Quimica

    2011-07-01

    CeO{sub 2} and mixed CeO{sub 2}-ZrO{sub 2} nanopowders were synthesized and efficiently deposited onto cordierite substrates, with the evaluation of their morphologic and structural properties through XRD, SEM, and FTIR. The modified substrates were employed as outer heterogeneous catalysts for reducing the soot originated from the diesel and diesel/biodiesel blends incomplete combustion. Their activity was evaluated in a diesel stationary motor, and a comparative analysis of the soot emission was carried out through diffuse reflectance spectroscopy. The analyses have shown that the catalyst-impregnated cordierite samples are very efficient for soot oxidation, being capable of reducing the soot emission in more than 60%. (author)

  9. The Kinetics Research of Diesel Catalytic Oxidation Desulfurization%柴油催化氧化脱硫反应动力学的研究

    Institute of Scientific and Technical Information of China (English)

    艾抚宾; 祁文博; 徐彤; 王海波; 勾连科; 宋丽芝

    2015-01-01

    The kinetics of diesel catalytic oxidation desulfurization is studied. A universal equation is obtained by the regression of the experimental data. The study on kinetics of diesel catalytic oxidation desulfurization shows: when concentration of reactant is constant, reaction speed is inversely proportional to the square of reaction time, indicating that the reaction is a quick response. This reaction has a low energy of apparent activation and reaction control steps are not reaction steps, but the diffusion step. The dynamic equation can be used as the basis for the industrial design of the device.%对柴油催化氧化脱硫反应进行了动力学研究,对试验数据进行回归计算后得到了温度对该反应影响的经验性关系式。由柴油催化氧化脱硫反应动力学研究可知,在反应物初始浓度一定的条件下,反应速度与反应时间的平方成反比,说明该反应是一个快速反应;该反应的表观活化能较小,反应的控制步骤不是反应步骤,而是扩散步骤。该动力学方程的计算值与试验值拟合较好,该方程可以作为中试放大及工业生产装置设计的依据。

  10. 超声波技术在柴油氧化脱硫中的应用%Application of ultrasound technologies in diesel fuels oxidative desulfurization

    Institute of Scientific and Technical Information of China (English)

    刘先军; 王宝辉; 刘淑芝; 崔宝臣

    2011-01-01

    介绍了超声波在H2O2-无机酸、H2O2-有机酸" H2O2-固体酸、Fenton试剂氧化柴油脱硫技术中的应用,其中超声波-Fenton试剂氧化脱硫效果较好,极有可能获得更广阔的工业化前景.SulphCo已成功的应用超声波在相当低的温度和压力条件下使用一套5000桶/d的可移动的超声裂化装置对柴油进行脱硫处理,该装置造价比新的高压加氢装置低50%,在柴油精制中应用该技术总成本也非常低.同时,对柴油超声波氧化脱硫技术的应用前景进行了展望.%Several ultrasound-assisted oxidative desulfurization(UAOD)technologies were reviewed,including H2O2- inorganic acid systems and H2O2- organic acid systems and Fenton' s reagent systems.The UAOD technologies in combination with Fenton' s reagent showed a good desulfurization effect.SulphCo has successfully used a 5000 barrel/d mobile Sonocracking unit to duplicate on a commercial scale its proprietary process that applies ultrasonics at relatively low temperatures and pressures.The UAOD technology estimate capital costs less than half the cost of a new high-pressure hydrotreater.The total costs of the Sonocracking technology in many diesel finishing applications are much cheaper.The opinions with respect to the future application trend of ultrasound-assisted oxidative desulfurization technologies of diesel fuels are proposed.

  11. Exposure and Health Effects Review of Engineered Nanoscale Cerium and Cerium Dioxide Associated with its Use as a Fuel Additive - NOW IN PRINT IN THE JOURNAL

    Science.gov (United States)

    Advances of nanoscale science have produced nanomaterials with unique physical and chemical properties at commercial levels that are now incorporated into over 1000 products. Nanoscale cerium (di) oxide (Ce02) has recently gained a wide range of applications which includes coatin...

  12. The Effect of H2O2-HCOOH-Activataed Carbon Catalytic Oxidation System on Diesel Composition%H2O2-HCOOH-活性炭氧化脱硫体系对柴油组分影响

    Institute of Scientific and Technical Information of China (English)

    姬乔娜

    2012-01-01

    H2O2-HCOOH-activated carbon catalytic oxidation system was used to remove the thiophenic sulfur in diesel fuel.But whether the diesel destructed by the system was unknown.The composition of diesel was determined by gas chromatography-mass spectrometry(GC-MS).Results showed the system could reduce the content of arene and alkene in diesel,so the proportion of saturated hydrocarbons increased,which was positive for the quality of diesel.%H2O2-HCOOH-活性炭氧化体系可深度脱除柴油中噻吩类硫化物[1],但是否会破坏柴油中的有效成分,尚未见报道。本文用气相色谱-质谱(GC-MS)测定柴油的组分及含量,旨在分析柴油品质的变化。结果表明:该体系可减少柴油中芳烃和烯烃的含量,提高烷烃所占比例,对柴油成分的影响是积极的。

  13. Investigation of the Effect of Yttrium Oxide Nanoparticles Doped with Cerium and Neodymium on Electro-Optics of Liquid Crystal Polymer Composites

    Science.gov (United States)

    Zharkova, G. M.; Osipov, V. V.; Platonov, V. V.; Podkin, A. V.; Strel'tsov, S. A.

    2016-12-01

    Morphology and properties of liquid crystal polymer composites doped with inorganic nanoparticles are described. These composites comprised nematic liquid crystal 5CB, polyvinyl acetate, and nanoparticles of oxides (Y2O3, CeO2:Y2O3, and Nd2O3:Y2O3). Nanopowders were synthesized by the laser method of vaporization of a solid target under CO2-laser or fiber ytterbium laser irradiation. The effect of oxides on the electro-optical properties of the composites and times of response to an electrical pulse is investigated. It is shown that incorporation of CeO2:Y2O3 nanopowder in liquid crystal polymer composites affects the decrease of the control field and the increase of light transmission in an electric field stronger than incorporation of Nd2O3:Y2O3 nanoparticles.

  14. The Preparation and Characterization of Mesoporous Cerium Dioxide and Its Properties in the Oxidation of CO%介孔二氧化铈的制备、表征以及对CO的氧化性能研究

    Institute of Scientific and Technical Information of China (English)

    田俊杰; 纳薇; 王华; 高文桂; 刘自松; 郭伟

    2013-01-01

    以无机盐硝酸铈和柠檬酸为原料,CTAB(十六烷基三甲基溴化铵)为模板剂,采用水热法制备了大比表面积的介孔CeO2,结合X射线粉末衍射(XRD)、N2吸附与脱附、H2程序升温还原(H2-TPR)和CO2程序升温脱附(CO2-TPD)等表征手段研究了CTAB加入及焙烧温度对介孔CeO2晶型结构和比表面积的影响,并对CO氧化催化机理进行了初步探讨.结果表明:前驱体与焙烧样品都具有晶型较好的CeO2立方萤石晶相结构和较大的比表面积,CTAB的加入不仅增大了样品的比表面积和孔容,而且在一定程度上提高了样品的结晶度;与其他样品相比,加入CTAB焙烧后的样品具有较好的催化效果.%High surface area mesoporous CeO2 was synthesized using inorganic salt nitric acid cerium and citric acid as raw materials and CTAB (hexadecyl trimethyl ammonium bromide) as template via hydrothermal method. The X-ray powder diffraction (XRD), N2 adsorption and desorption, H2 temperature programmed reduction(H2-TPR) and CO2 temperature programmed desorption(CO2-TPD) were used to study the crystal structure and surface area as well as the mechanism of CO oxidation of the obtained mesoporous CeO2 samples. The results show that all of the samples have pure CeO2 cubic fluorite crystalline structure and a high surface area. The addition of CTAB has not only improved surface area and pore volume of the products, but also enhanced the crystallinity of obtained CeO2. The sample which in the presence of CTAB exhibits a more excellent catalytic activity for CO oxidation rather than the other samples.

  15. Catalytic conversion of carbon dioxide into dimethyl carbonate using reduced copper-cerium oxide catalysts as low as 353 K and 1.3 MPa and the reaction mechanism

    Directory of Open Access Journals (Sweden)

    Seiki eWada

    2013-06-01

    Full Text Available Synthesis of dimethyl carbonate (DMC from CO2 and methanol under milder reaction conditions was performed using reduced cerium oxide catalysts and reduced copper-promoted Ce oxide catalysts. Although the conversion of methanol was low (0.005–0.11% for 2 h of reaction, DMC was synthesized as low as 353 K and at total pressure of as low as 1.3 MPa using reduced Cu–CeO2 catalyst (0.5 wt% of Cu. The apparent activation energy was 120 kJ mol–1 and the DMC synthesis rates were proportional to the partial pressure of CO2. An optimum amount of Cu addition to CeO2 was 0.1 wt% for DMC synthesis under the conditions at 393 K and total pressure of 1.3 MPa for 2 h (conversion of methanol: 0.15% due to the compromise of two effects of Cu: the activation of H2 during reduction prior to the kinetic tests and the block (cover of the surface active site. The reduction effects in H2 were monitored through the reduction of Ce4+ sites to Ce3+ based on the shoulder peak intensity at 5727 eV in the Ce L3-edge X-ray absorption near-edge structure (XANES. The Ce3+ content was 10% for reduced CeO2 catalyst whereas it increased to 15% for reduced Cu–CeO2 catalyst (0.5wt% of Cu. Moreover, the content of reduced Ce3+ sites (10% associated with the surface O vacancy (defect sites decreased to 5% under CO2 at 290 K for reduced Cu–CeO2 catalyst (0.1wt% of Cu. The adsorption step of CO2 on the defect sites might be the key step in DMC synthesis and thus the DMC synthesis rate dependence on the partial pressure of CO2 was proportional. Subsequent H atom subtraction steps from methanol at the neighboring surface Lewis base sites should combine two methoxy species to the adsorbed CO2 to form DMC, water, and restore the surface O vacancy.

  16. Acute effects of diesel exhaust particles and cisplatin on oxidative stress in cultured human kidney (HEK 293) cells, and the influence of curcumin thereon.

    Science.gov (United States)

    Waly, Mostafa I; Ali, Badreldin H; Nemmar, Abderrahim

    2013-12-01

    Particulate air pollution with particle diameters less than 2.5μm contribute to respiratory and extra-respiratory morbidity and mortality. We have recently reported the first in vivo experimental evidence that Diesel exhaust particles (DEP) in the lung aggravated the renal, pulmonary, and systemic effects of cisplatin (CP)-induced acute renal failure in rats. This in vitro study sought to determine whether and to what extent does DEP exposure exacerbate the effects of CP-induced oxidative stress in human embryonic kidney (HEK-293) cells, and to examine if these effects could be mitigated/prevented with curcumin (the yellow pigment isolated from turmeric). Cells viability, cysteine uptake and oxidative stress indices [glutathione (GSH), total antioxidant capacity (TAC), and the activities of antioxidant enzymes (catalase; glutathione peroxidase; superoxide dismutase)] were evaluated in all study groups. DEP aggravated the CP- induced HEK-293 cells toxicity, as evidenced by decreasing cell viability and by inducing oxidative stress (GSH depletion, TAC impairment, and antioxidant enzymes inhibition). DEP, but not CP, significantly reduced cysteine uptake. Curcumin prevented the observed DEP and CP-induced cellular insults. These findings suggest that DEP augmented the CP-induced toxicity in HEK-293 cells. Curcumin exhibited a strong potential for protection against DEP and CP-induced cytotoxicity.

  17. Dissolution properties of cerium dibutylphosphate corrosion inhibitors

    NARCIS (Netherlands)

    Soestbergen, M. van; Erich, S.J.F.; Huinink, H.P.; Adan, O.C.G.

    2013-01-01

    The corrosion inhibitor cerium dibutylphosphate, Ce(dbp)3, prevents corrosion by cerium and dbp deposition at the alkaline cathode and acidic anode respectively. The pH dependent Ce(dbp)3 solubility seems to play an essential role in the inhibition degree. We found that Ce(dbp) 3 scarcely dissolves

  18. pH-distribution of cerium species in aqueous systems

    Institute of Scientific and Technical Information of China (English)

    B.Bouchaud; J.Balmain; G.Bonnet; F.Pedraza

    2012-01-01

    Cerium-based oxide coalings can be obtained through either chemical or electrochemical processes on various conductor and semiconductor substrates.In both cases the films develop through a precipitation mechanism,which strongly depends on the solution chemistry.In the particular case of the electrolytic approach,the elaboration parameters play a key role on the interfacial pH modification thereby leading to an indirect precipitation mechanism.Indeed,the nucleation and growth mechanisms of crystallites and the composition of the resulting layers have been shown to be also strongly affected by the deposition conditions as well as by the substrate composition,which could in turn modify the protectiveness provided by such coatings.Therefore a better fundamental understanding of the system is required,in particular of the distribution of cerium-containing species in aqueous solution.To this end,the present work intended to develop a diagram showing the distribution as well as the relative amount of Ce(Ⅲ)/Ce(Ⅳ) species in aqueous media as a function of the pH range.The resulting pH-distribution diagram turned out to be a useful tool to predict the relevant precipitation mechanisms and species involved during the growth of cerium-containing films and to draw correlations with the characteristics of the as-deposited films.

  19. Catalytic oxidation degradation of marine diesel pollution by horseradish peroxidase%用辣根过氧化物酶催化降解海水中柴油污染的研究

    Institute of Scientific and Technical Information of China (English)

    尚晓琳; 于晓彩; 季秋忆; 张健; 吴云英; 杨利

    2016-01-01

    为深入探索酶催化技术在海洋石油污染处理中的应用,以游离辣根过氧化物酶( HRP)催化降解海水中柴油污染,研究了酶用量、溶液pH值、柴油初始浓度和催化反应时间等因素对酶催化降解海水中柴油污染的影响,确定了HRP催化降解海水中柴油污染的优化工艺条件,同时考察了反应助剂对海水中柴油污染去除率的影响。结果表明: HRP能有效催化降解海水的柴油污染,当海水中柴油的质量浓度为1.2 g/L时,在温度为25℃、 HRP加入量为1.6 U/mL、 H2 O2为250 mg/L、溶液pH为5的条件下,催化降解3 h,柴油去除率可达90.77%;聚乙二醇( PEG)对HRP催化降解海水中的柴油污染有较显著的影响。%The influence of dosage, solution pH value, diesel initial concentration and catalytic period on free horseradish peroxidase ( HRP) degradation of marine diesel pollution were studied and optimized for the process conditions by orthogonal experiment to exploite utilization of horseradish peroxidase in the catalytic oxidation degra-dation of marine diesel pollution. The removal of marine diesel pollution by a reaction promoter was observed. The results showed that free horseradish peroxidase was shown to degradate the diesel pollution in the seawater effective-ly under the optimum conditions of diesel initial concentration of 1. 2 g/L, temperature of 25℃, HRP activity con-centration of 1. 6 U/mL, H2 O2 mass concentration of 250 mg/L, pH 7. 5 and reaction time of 3 h, with the diesel removal rate of 90. 77%. It was found that polyethylene glycol ( PEG) improved the efficiency for HRP catalytic oxidation in seawater diesel pollution.

  20. Promotional effects of cerium doping and NOx on the catalytic soot combustion over MnMgAlO hydrotalcite-based mixed oxides

    Institute of Scientific and Technical Information of China (English)

    李倩; 王晓; 常伟; 陈慧; 张昭良

    2014-01-01

    A series of MnMgAlO samples with different amounts of Ce doping were facilely prepared using coprecipitation method and their catalytic soot combustion activity was evaluated by temperature programmed oxidation reaction (TPO). The methods of X-ray diffraction (XRD), Brumauer-Emmett-Teller (BET), H2-TPR, NO-TPO and in situ IR were used to characterize the physio-chemical properties of these samples. Dopant Ce improved the soot combustion performance of MnMgAlO catalyst due to the en-hanced redox ability. Introduction of NOx led to the further increase of catalytic soot oxidation activity on these samples. Over Ce-containing samples, the catalytic activity was slightly decreased as the amount of dopant Ce increased in O2. Differently, in NO+O2, a certain amount of dopant Ce was much more favorable and excess amount of Ce resulted in a sharp drop of the catalytic soot combustion activity. Both NO2 and nitrates were found to have great contributions to the effects of NOx on the soot combustion activity of Ce-doped catalysts. More NO2 was generated as dopant Ce increased. When appropriate amount of Ce was introduced, the as-formed NO2 was stored as bridging bidentate nitrate on Mn-Ce site, which was confirmed to have higher reactivity with soot than nitrite or monodentate nitrate on Mn and/or Ce sites. Overall, Mn0.5Mg2.5Ce0.1Al0.9O was considered as the most potential catalyst for soot combustion.

  1. Diesel/biodiesel soot oxidation with ceo2 and ceo2-zro2-modified cordierites: a facile way of accounting for their catalytic ability in fuel combustion processes

    OpenAIRE

    Silva,Rodrigo F.; Edimar DeOliveira; Paulo C. de Sousa Filho; Neri,Cláudio R.; OSVALDO A. SERRA

    2011-01-01

    CeO2 and mixed CeO2-ZrO2 nanopowders were synthesized and efficiently deposited onto cordierite substrates, with the evaluation of their morphologic and structural properties through XRD, SEM, and FTIR. The modified substrates were employed as outer heterogeneous catalysts for reducing the soot originated from the diesel and diesel/biodiesel blends incomplete combustion. Their activity was evaluated in a diesel stationary motor, and a comparative analysis of the soot emission was carried out ...

  2. Quercetin attenuates oxidative damage induced by treatment of embryonic chicken spermatogonial cells with 4-nitro-3-phenylphenol in diesel exhaust particles.

    Science.gov (United States)

    Mi, Yuling; Zhang, Caiqiao; Li, ChunMei; Taneda, Shinji; Watanabe, Gen; Suzuki, Akira K; Taya, Kazuyoshi

    2010-01-01

    Quercetin, an antioxidant flavonoid, is considered beneficial for human and animal health. In this study, the protective effect of quercetin on oxidative damage to testicular cells was studied in embryonic chickens after treatment with 4-nitro-3-phenylphenol (PNMPP) derived from diesel exhaust particles. Testicular cells were challenged with PNMPP (10(-8)-10(-6) M) alone and in combination with quercetin for 48 h. The results showed that quercetin manifested no deleterious effect on spermatogonial cells up to 1.0 microg/ml. Exposure to PNMPP (10(-6) M) induced condensed nuclei and vacuolated cytoplasm and reductions in testicular cell viability and spermatogonial cell numbers (p<0.05). It also induced lipid peroxidation by an elevation of thiobarbituric acid reactive substances and decreased glutathione peroxidase activity and superoxide dismutase activity (p<0.05). Simultaneous supplementation with quercetin restored these parameters to the same levels as in the control. These data indicate that quercetin protects spermatogonial cells from oxidative damage in embryonic chickens intoxicated with PNMPP.

  3. Characterization and ecological risk assessment of nanoparticulate CeO2 as a diesel fuel catalyst.

    Science.gov (United States)

    Batley, Graeme E; Halliburton, Brendan; Kirby, Jason K; Doolette, Casey L; Navarro, Divina; McLaughlin, Mike J; Veitch, Colin

    2013-08-01

    Nanoparticulate cerium dioxide (nano-CeO2 ), when combusted as an additive to diesel fuel, was transformed from 6 nm to 14 nm sizes into particles near 43 nm, with no obvious change in the unit cell dimensions or crystalline form. Cerium sulfate, if formed during combustion, was below detection limits. Ceria nanoparticles were agglomerated within the soot matrix, with a mean aerodynamic diameter near 100 nm. The dissolution of cerium from the dried ceria catalyst in synthetic soft water was extremely small (<0.0006% or <0.2 µg Ce/L), with particles being highly agglomerated (<450 nm). Agglomeration was reduced in the presence of humic acid. In the combusted samples, soot was dominant, and the solubility of cerium in soft water showed an almost 100-fold increase in the <1 nm fraction compared to that before combustion. It appeared that the nano-CeO2 remained agglomerated within the soot matrix and would not be present as dispersed nanoparticles in aquatic or soil environments. Despite the increased dissolution, the solubility was not sufficient for the combusted ceria to represent a risk in aquatic ecosystems. The predicted environmental concentrations were still orders of magnitude below the predicted no effects concentration of near 1 mg/L. In the soil environment, any cerium released from soot materials would interact with natural colloids, decreasing cerium concentrations in soil solutions and further minimizing the potential risk to soil organisms.

  4. Zinc, copper, or cerium accumulation from metal oxide nanoparticles or ions in sweet potato: Yield effects and projected dietary intake from consumption.

    Science.gov (United States)

    Bradfield, Scott J; Kumar, Pawan; White, Jason C; Ebbs, Stephen D

    2017-01-01

    The potential release of metal oxide engineered nanoparticles (ENP) into agricultural systems has created the need to evaluate the impact of these materials on crop yield and food safety. The study here grew sweet potato (Ipomoea batatas) to maturity in field microcosms using substrate amended with three concentrations (100, 500 or 1000 mg kg DW(-1)) of either nZnO, nCuO, or nCeO2 or equivalent amounts of Zn(2+), Cu(2+), or Ce(4+). Adverse effects on tuber biomass were observed only for the highest concentration of Zn or Cu applied. Exposure to both forms of Ce had no adverse effect on yield and a slight positive benefit at higher concentrations on tuber diameter. The three metals accumulated in both the peel and flesh of the sweet potato tubers, with concentrations higher in the peel than the flesh for each element. For Zn, >70% of the metal was in the flesh and for Cu >50%. The peels retained 75-95% of Ce in the tubers. The projected dietary intake of each metal by seven age-mass classes from child to adult only exceeded the oral reference dose for chronic toxicity in a scenario where children consumed tubers grown at the highest metal concentration. The results throughout were generally not different between the ENP- and ionic-treatments, suggesting that the added ENPs underwent dissolution to release their component ions prior to accumulation. The results offer insight into the fate and impact of these ENPs in soils. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  5. Tetrabromobisphenol A photoelectrocatalytic degradation using reduced graphene oxide and cerium dioxide comodified TiO2 nanotube arrays as electrode under visible light.

    Science.gov (United States)

    Zhou, Qingxiang; Xing, An; Zhao, Danchen; Zhao, Kuifu

    2016-12-01

    Tetrabromobisphenol A, one of the most important brominated retardants, is an typical persistent organic pollutant and it is of great value to develop rapid and effective degradation method. Present study established a photoelectrodegradation method with CeO2 and reduced graphene oxide co-modified TiO2 nanotube arrays (RGO-CeO2-TiO2 NAs), which were successfully synthesized and characterized with scanning electron microscopy (SEM) and Energy Dispersive X Ray Spectrometry (EDX). The SEM Images revealed that the nanotubes had a diameter of about 100 nm and an obvious layer of CeO2 and RGO on the surface of TiO2 nanotube arrays. The EDX data exhibited the presence of Ce element. The results demonstrated that TBBPA was degraded at a high degradation rate constant of 0.0191 min(-1), and photogenerated holes played a major role in the degradation reaction. Significant decrease of degradation efficiency was achieved with the presence of EDTA-2Na(hole scavenger), yet while the existence of t-BuOH(OH scavenger) resulted in less inhibition on the degradation. Besides, RGO-CeO2-TiO2 NAs exhibited good stability with rarely decline of degradation efficiency for ten reused runs. All these indicated that RGO-CeO2-TiO2 NAs were a good catalyst with extraordinary catalytic activity and stability for PEC degradation, and would have great potential in the control and removal of pollutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Ultra-deep oxidative desulfurization of diesel fuel with H{sub 2}O{sub 2} catalyzed under mild conditions by polymolybdates supported on Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Gutierrez, Jose Luis; Murrieta, Florentino; Navarrete, Juan; Jimenez-Cruz, Federico [Instituto Mexicano del Petroleo, Programa de Procesos y Reactores, Eje Central Lazaro Cardenas 152, 07730 Mexico D.F. (Mexico); Fuentes, Gustavo A.; Hernandez-Teran, Maria Eugenia [Area de Ingenieria Quimica, Universidad A. Metropolitana-Iztapalapa, 09340 Mexico D.F. (Mexico)

    2006-05-17

    The evaluation of the catalytic oxidative desulfurization (OD) activity of alumina-supported polymolybdates (Mo/Al{sub 2}O{sub 3}) was carried out using organosulfur model compounds and diesel fuel. Hydrogen peroxide was the oxidizing reagent. Ultra-deep desulfurization, 97.8% removal of sulfur in diesel fuel, was achieved by reaction under mild conditions followed by solvent extraction. The catalyst was prepared by equilibrium adsorption and characterized by infrared, Raman, X-ray photoelectron, {sup 31}P and {sup 27}Al MAS NMR spectroscopies. Our results indicate that the phosphomolybdate used during synthesis of the catalysts decomposes and forms hydrated hepta- and octamolybdates as well as phosphate ions on the surface of alumina. (author)

  7. Prolonged Pulmonary Exposure to Diesel Exhaust Particles Exacerbates Renal Oxidative Stress, Inflammation and DNA Damage in Mice with Adenine-Induced Chronic Renal Failure

    Directory of Open Access Journals (Sweden)

    Abderrahim Nemmar

    2016-05-01

    Full Text Available Background/Aims: Epidemiological evidence indicates that patients with chronic kidney diseases have increased susceptibility to adverse outcomes related to long-term exposure to particulate air pollution. However, mechanisms underlying these effects are not fully understood. Methods: Presently, we assessed the effect of prolonged exposure to diesel exhaust particles (DEP on chronic renal failure induced by adenine (0.25% w/w in feed for 4 weeks, which is known to involve inflammation and oxidative stress. DEP (0.5m/kg was intratracheally (i.t. instilled every 4th day for 4 weeks (7 i.t. instillation. Four days following the last exposure to either DEP or saline (control, various renal endpoints were measured. Results: While body weight was decreased, kidney weight increased in DEP+adenine versus saline+adenine or DEP. Water intake, urine volume, relative kidney weight were significantly increased in adenine+DEP versus DEP and adenine+saline versus saline. Plasma creatinine and urea increased and creatinine clearance decreased in adenine+DEP versus DEP and adenine+saline versus saline. Tumor necrosis factor α, lipid peroxidation and reactive oxygen species were significantly increased in adenine+DEP compared with either DEP or adenine+saline. The antioxidant calase was significantly decreased in adenine+DEP compared with either adenine+saline or DEP. Notably, renal DNA damage was significantly potentiated in adenine+DEP compared with either adenine+saline or DEP. Similarly, systolic blood pressure was increased in adenine+DEP versus adenine+saline or DEP, and in DEP versus saline. Histological evaluation revealed more collagen deposition, higher number of necrotic cell counts and dilated tubules, cast formation and collapsing glomeruli in adenine+DEP versus adenine+saline or DEP. Conclusion: Prolonged pulmonary exposure to diesel exhaust particles worsen renal oxidative stress, inflammation and DNA damage in mice with adenine-induced chronic

  8. Options for the recovery of cerium by solvent extraction

    Energy Technology Data Exchange (ETDEWEB)

    Soldenhoff, K.H. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    This paper reports the results of an experimental program to examine the use of various commercial reagents for the extraction of cerium (IV) from sulphate solutions. Extractants tested include organophosphorus esters (TOPO, Cyanex 923 and Cyanex 925), organophosphorus acids (DEHPA, lonquest 801 and Cyanex 272) and high molecular weight amine, Alamine 336. The suitability of reagents is assessed in terms of process relevant criteria such as extraction dependence on acidity, selectivity over other rare earths and thorium, stability of reagent towards oxidation and loading characteristics. (author) 15 refs., 2 tabs., 5 figs.

  9. Study on Kinetics for Desulfurization of Model Diesel

    Institute of Scientific and Technical Information of China (English)

    Qian Jianhua; Zhou Yuenan; Liu Lin; Wang Yue; Xing Jinjuan; Lü Hong

    2009-01-01

    In this study, by means of the experiments for desulfurization of model diesel through oxi-dative extraction, the changes associated with the rate of desulfurization of diesel and the mechanism for oxidation of sulfides in diesel were explored. Through studying the mechanism for oxidation of sulfides and the principle of solvent extraction, the kinetic equation of desulfurization via oxidative extraction were determined. By means of the evaluation of model parameters and curve fitting, the reaction order between organic sulfide and sulfone, the intrinsic oxidation rate constant of organic sulfide and sulfone, and the equilibrium constant between suifone in model diesel and extractive sol-vent were determined. The experimental values of the desulfurization rate and the theoretical values of the corresponding model equation had closely demonstrated that the desulfurization reaction rate had high accuracy. And the reaction kinetics could provide an important basis for diesel desulfurization process in the future.

  10. LUMINESCENT PROPERTIES OF SILICATE GLASSES WITH CERIUM IONS AND ANTIMONY

    Directory of Open Access Journals (Sweden)

    A. M. Klykova

    2014-05-01

    Full Text Available The paper deals with the results of an experimental study of luminescence excitation spectra and luminescence of silicate glasses containing cerium ions and antimony. The aim of this work was to study the features of the luminescence and the effect of UV irradiation and heat treatment on luminescence and the state of cerium ions and antimony in glass. We investigated glass system Na2O-ZnO-Al2O3-SiO2-NaF-NaBr with additives CeO2 and Sb2O3. Synthesis was carried out in platinum crucibles in the air at 14500C. The samples were polished glass plates with a thickness of 0.5-1 mm. UV irradiation was carried out with a mercury lamp having a wide range of radiation in the spectral range 240-390 nm. It was conducted in a Nabertherm muffle furnaces. Luminescence spectra and excitation spectra were measured using a spectrofluorimeter MPF-44A (PerkinElmer at the room temperature. Measured luminescence spectra were corrected in view of the spectral sensitivity of the photodetector for spectrofluorimeter. Adjustment of the excitation spectra for the spectral dependence of the intensity of the excitation source was not carried out. During the experiments it was found that in silicate glasses Sb3+ ions can exist in two energy states, which corresponds to a different environment with oxygen ions. Heat treatment of these glasses in an oxidizing atmosphere leads to an increase in ion concentration of Sb3+ ions with a greater amount of oxygen in the environment. In glasses containing antimony and cerium ions, ultraviolet irradiation causes a change in the valence of cerium ions and antimony, which is accompanied by luminescence quenching. Subsequent heat treatment of glass leads to the inverse processes and restore luminescence excitation spectra. The study of fluorescent properties of silicate glasses with cerium and antimony ions led to the conclusion of the practical significance of this work. Promising multifunctional materials can be created on the basis of

  11. Inhibition of endothelial nitric oxide synthase activity and suppression of endothelium-dependent vasorelaxation by 1,2-naphthoquinone, a component of diesel exhaust particles

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yang; Taguchi, Keiko; Sumi, Daigo [University of Tsukuba, Department of Environmental Medicine, Doctoral Programs in Medical Sciences, Graduate School of Comprehensive Sciences, Ibaraki (Japan); Yamano, Shigeru [Fukuoka University, Faculty of Pharmaceutical Sciences, Fukuoka (Japan); Kumagai, Yoshito [University of Tsukuba, Department of Environmental Medicine, Doctoral Programs in Medical Sciences, Graduate School of Comprehensive Sciences, Ibaraki (Japan); Southern California Particle Center and Supersite, Los Angeles, CA (United States)

    2006-05-15

    Diesel exhaust particles contain redox-active quinones, such as 9,10-phenanthraquinone (9,10-PQ) and 1,2-naphthoquinone (1,2-NQ), which act as potent electron acceptors, thereby altering electron transfer on proteins. We have previously found that 9,10-PQ inhibits constitutive nitric oxide synthase (NOS) activity, by shunting electrons away from NADPH on the cytochrome P450 reductase domain of NOS, and thus suppresses acetylcholine (Ach)-induced vasorelaxation in the aortic ring. However, the effect of 1,2-NQ on endothelial NOS (eNOS) activity is still poorly understood. With the membrane fraction of cultured bovine aortic endothelial cells, we found that 1,2-NQ was a potent inhibitor of eNOS with an IC{sub 50} value of 1.4 {mu}M, whereas trans-1,2-dihydroxy-1,2-dihydronaphthalene (1,2-DDN), a redox-negative naphthalene analog of 1,2-NQ, did not show such an inhibitory action. Although 1,2-DDN (5 {mu}M) did not affect Ach-mediated vasorelaxation, 1,2-NQ caused a significant suppression of Ach-induced endothelium-dependent vasorelaxation in the aortic ring. However, 1,2-NQ did not affect sodium nitroprusside-induced endothelium-independent vasorelaxation. These results suggest that 1,2-NQ is an environmental quinone that inhibits eNOS activity, thereby disrupting NO-dependent vascular tone. (orig.)

  12. Growth of transition metals on cerium tungstate model catalyst layers

    Science.gov (United States)

    Skála, T.; Tsud, N.; Stetsovych, V.; Mysliveček, J.; Matolín, V.

    2016-10-01

    Two model catalytic metal/oxide systems were investigated by photoelectron spectroscopy and scanning tunneling microscopy. The mixed-oxide support was a cerium tungstate epitaxial thin layer grown in situ on the W(1 1 0) single crystal. Active particles consisted of palladium and platinum 3D islands deposited on the tungstate surface at 300 K. Both metals were found to interact weakly with the oxide support and the original chemical state of both support and metals was mostly preserved. Electronic and morphological changes are discussed during the metal growth and after post-annealing at temperatures up to 700 K. Partial transition-metal coalescence and self-cleaning from the CO and carbon impurities were observed.

  13. Particulate morphology of waste cooking oil biodiesel and diesel in a heavy duty diesel engine

    Science.gov (United States)

    Hwang, Joonsik; Jung, Yongjin; Bae, Choongsik

    2014-08-01

    The effect of biodiesel produced from waste cooking oil (WCO) on the particulate matters (PM) of a direct injection (DI) diesel engine was experimentally investigated and compared with commercial diesel fuel. Soot agglomerates were collected with a thermophoretic sampling device installed in the exhaust pipe of the engine. The morphology of soot particles was analyzed using high resolution transmission electron microscopy (TEM). The elemental and thermogravimetric analysis (TGA) were also conducted to study chemical composition of soot particles. Based on the TEM images, it was revealed that the soot derived from WCO biodiesel has a highly graphitic shell-core arrangement compared to diesel soot. The mean size was measured from averaging 400 primary particles for WCO biodiesel and diesel respectively. The values for WCO biodiesel indicated 19.9 nm which was smaller than diesel's 23.7 nm. From the TGA results, WCO biodiesel showed faster oxidation process. While the oxidation of soot particles from diesel continued until 660°C, WCO biodiesel soot oxidation terminated at 560°C. Elemental analysis results showed that the diesel soot was mainly composed of carbon and hydrogen. On the other hand, WCO biodiesel soot contained high amount of oxygen species.

  14. Geochemical and Microbiological Characteristics during in Situ Chemical Oxidation and in Situ Bioremediation at a Diesel Contaminated Site

    NARCIS (Netherlands)

    Sutton, N.B.; Kalisz, M.; Krupanek, J.; Marek, J.; Grotenhuis, J.T.C.; Smidt, H.; Weert, de J.; Rijnaarts, H.H.M.; Gaans, van P.; Keijzer, T.

    2014-01-01

    While in situ chemical oxidation with persulfate has seen wide commercial application, investigations into the impacts on groundwater characteristics, microbial communities and soil structure are limited. To better understand the interactions of persulfate with the subsurface and to determine the co

  15. Luminescence properties and decay kinetics of nano ZnO powder doped with cerium ions

    Energy Technology Data Exchange (ETDEWEB)

    Panda, Nihar Ranjan, E-mail: nihar@iitbbs.ac.in [Indian Institute of Technology Bhubaneswar, Bhubaneswar 751013, Orissa (India); Acharya, B.S., E-mail: bsacharya1950@gmail.com [Department of Physics, C.V. Raman College of Engineering, Bhubaneswar 752054, Orissa (India); Singh, Th. Basanta [Luminescence Dating Laboratory, Manipur University, Imphal 795003 (India); Gartia, R.K. [Department of Physics, Manipur University, Imphal 795003 (India)

    2013-04-15

    ZnO nanopowders doped with cerium ions (1.2 and 1.5 at. wt.%) were synthesized through soft solution route using ultrasound. Sonication has been found to be an effective way for doping rare earth ions like cerium into ZnO. This was confirmed from energy dispersive analysis of X-rays (EDAX) measurement. Further, optical absorption and photoluminescence (PL) measurements corroborate this finding. X-ray diffraction (XRD) studies show the increase of crystallite size and unit cell volume with doping of cerium ions. Formation of fibrous structure of ZnO:Ce was observed from the transmission electron microscopy (TEM) measurements. Although the structural measurements indicate Ce{sup 4+} ion occupying substitutional site in ZnO, PL and absorption studies confirmed the presence of Ce{sup 3+} ion in the powder. The coexistence of Ce{sup 3+} and Ce{sup 4+} ions has been explained on the basis of conversion of Ce{sup 3+} to Ce{sup 4+} in the oxidizing environment. Thermoluminescence (TL) and photo-stimulated decay of luminescence (PSDL) decay studies give an idea of various trapping levels present in the band gap of ZnO. These traps release electrons during optical stimulation to give bimolecular kinetics in nano ZnO:Ce powders. -- Highlights: ► Sonication: an effective way of incorporation of cerium ions into ZnO. ► Site dependent characteristic emission of cerium. ► Energy transfer from host lattice to cerium ions. ► Mono and bimolecular kinetics of ZnO:Ce.

  16. Titrimetric and Spectrophotometric Methods for the Assay of Ketotifen Using Cerium(IV and Two Reagents

    Directory of Open Access Journals (Sweden)

    Madihalli Srinivas Raghu

    2013-01-01

    Full Text Available One titrimetric and two spectrophotometric methods are described for the determination of ketotifen fumarate (KTF in bulk drug and in tablets using cerium(IV as the oxidimetric agent. In titrimetry (method A, the drug was treated with a measured excess of cerium(IV in H2SO4 medium and after a standing time of 10 min, the surplus oxidant was determined by back titration with iron(II. The spectrophotometric procedures involve addition of a known excess of cerium(IV to KTF in acid medium followed by the determination of unreacted oxidant by reacting with either p-dimethyl amino benzaldehyde and measuring the resulting colour at 460 nm (method B or o-dianisidine and subsequent measurement of the absorbance of coloured product at 470 nm (method C. Titrimetric assay is based on a 1 : 2 reaction stoichiometry between KTF and cerium(IV and the method is applicable over 2–18 mg range. In spectrophotometry, regression analysis of Beer’s law plots showed a good correlation in 0.4–8.0 and 0.4–10.0 g mL−1 KTF ranges for method B and method C, respectively, and the corresponding molar absorptivity coefficients are calculated to be and  L mol−1 cm−1.

  17. Effects of a nanoceria fuel additive on the physicochemical properties of diesel exhaust particles.

    Science.gov (United States)

    Zhang, Junfeng Jim; Lee, Ki-Bum; He, Linchen; Seiffert, Joanna; Subramaniam, Prasad; Yang, Letao; Chen, Shu; Maguire, Pierce; Mainelis, Gediminas; Schwander, Stephan; Tetley, Teresa; Porter, Alexandra; Ryan, Mary; Shaffer, Milo; Hu, Sheng; Gong, Jicheng; Chung, Kian Fan

    2016-10-12

    Nanoceria (i.e., CeO2 nanoparticles) fuel additives have been used in Europe and elsewhere to improve fuel efficiency. Previously we have shown that the use of a commercial fuel additive Envirox™ in a diesel-powered electricity generator reduced emissions of diesel exhaust particle (DEP) mass and other pollutants. However, such additives are currently not permitted for use in on-road vehicles in North America, largely due to limited data on the potential health impact. In this study, we characterized a variety of physicochemical properties of DEPs emitted from the same engine. Our methods include novel techniques such as Raman spectrometry for analyzing particle surface structure and an assay for DEP oxidative potential. Results show that with increasing Envirox™ concentrations in the fuel (0×, 0.1×, 1×, and 10× of manufacturer recommended 0.5 mL Envirox™ per liter fuel), DEP sizes decreased from 194.6 ± 20.1 to 116.3 ± 14.8 nm; the zeta potential changed from -28.4 mV to -22.65 mV; DEP carbon content decreased from 91.8% to 79.4%; cerium and nitrogen contents increased from 0.3% to 6.5% and 0.2% to 0.6%, respectively; the ratio of organic carbon (OC) to elemental carbon (EC) increased from 22.9% to 38.7%; and the ratio of the disordered carbon structure to the ordered carbon structure (graphitized carbon) in DEPs decreased. Compared to DEPs emitted from 0×, 0.1×, and 1× fuels, DEPs from the 10× fuel had a lower oxidative potential likely due to the increased ceria content because pure ceria nanoparticles exhibited the lowest oxidative potential compared to all the DEPs. Since the physicochemical parameters tested here are among the determinants of particle toxicity, our findings imply that adding ceria nanoparticles into diesel may alter the toxicity of DEPs. The findings from the present study, hence, can help future studies that will examine the impact of nanoceria additives on DEP toxicities.

  18. *Differential injury in healthy and cytokine-treated epithelial cells exposed to diesel exhaust particles involves interaction of superoxide and nitric oxide

    Science.gov (United States)

    RATIONALE: Individuals with chronic pulmonary inflammation due to disease are more susceptible to the adverse health effects associated with exposure to particulate matter (PM) air pollutants, such as diesel exhaust particles (DEP). Increasing evidence suggests that these adverse...

  19. ETV-DRAFT TEST REPORT OF MOBILE SOURCE EMISSIONS CONTROL DEVICES DONALDSON COMPANY,INC. SERIES 6100 DIESEL OXIDATION CATALYST MUFFLER

    Science.gov (United States)

    This report reflects verification testing of a catalytic muffler for diesel trucks. Produced by Donaldson Corp., it was tested on low sulfur and ultra low sulfur fuel, and shown to have reduced emissions.

  20. Diesel emissions in Vienna

    Science.gov (United States)

    Horvath, H.; Kreiner, I.; Norek, C.; Preining, O.; Georgi, B.

    The aerosol in a non-industrial town normally is dominated by emissions from vehicles. Whereas gasoline-powered cars normally only emit a small amount of particulates, the emission by diesel-powered cars is considerable. The aerosol particles produced by diesel engines consist of graphitic carbon (GC) with attached hydrocarbons (HCs) including also polyaromatic HCs. Therefore the diesel particles can be carcinogenic. Besides diesel vehicles, all other combustion processes are also a source for GC; thus source apportionment of diesel emissions to the GC in the town is difficult. A direct apportionment of diesel emissions has been made possible by marking all the diesel fuel used by the vehicles in Vienna by a normally not occurring and easily detectable substance. All emitted diesel particles thus were marked with the tracer and by analyzing the atmospheric samples for the marking substance we found that the mass concentrations of diesel particles in the atmosphere varied between 5 and 23 μg m -3. Busy streets and calm residential areas show less difference in mass concentration than expected. The deposition of diesel particles on the ground has been determined by collecting samples from the road surface. The concentration of the marking substance was below the detection limit before the marking period and a year after the period. During the period when marked diesel fuel was used, the concentrations of the diesel particles settling to the ground was 0.012-0.07 g g -1 of collected dust. A positive correlation between the diesel vehicle density and the sampled mass of diesel vehicles exists. In Vienna we have a background diesel particle concentration of 11 μg m -3. This value increases by 5.5 μg m -3 per 500 diesel vehicles h -1 passing near the sampling location. The mass fraction of diesel particles of the total aerosol mass varied between 12.2 and 33%; the higher values were found in more remote areas, since diesel particles apparently diffuse easily

  1. Particulate emissions from road transportation (gasoline and diesel). Chemical and granulometric characteristics; relative contribution; Emissions particulaires par les transports routiers (essence et diesel) caracteristiques chimiques et granulometriques contribution relative

    Energy Technology Data Exchange (ETDEWEB)

    Belot, G. [PSA-Peugiot-Citroen, 92 - La Garenne-Colombes (France)

    1996-12-31

    The formation process and chemical composition of diesel, leaded and lead-free gasoline combustion particulates are presented, and the effects of engine technology, post-treatments (oxidative catalysis), automobile speed and fuel type (more especially diesel type), on the granulometry of gasoline and diesel automotive particulates are studied. The emission contributions from the various diesel vehicle types (automobiles, trucks, buses), gasoline and diesel automobiles and other natural and anthropogenic particulate sources, are presented and compared

  2. Experimental studies on a DI diesel engine fueled with bioethanol-diesel emulsions

    Directory of Open Access Journals (Sweden)

    Dulari Hansdah

    2013-09-01

    Full Text Available This paper explores the possibility of utilizing bioethanol obtained from Madhuca Indica flower as an alternative fuel in a direct injection (DI diesel engine. Three different percentages of bioethanol (5%, 10%, and 15% on volume basis were emulsified with diesel proportionality with the help of a surfactant. The emulsions were designated as BMDE5, BMDE10, and BMDE15 where the numeric value refers to the percentage of bioethanol. The emulsions were tested as fuels in a single cylinder, four stroke, and air cooled DI diesel engine developing a power of 4.4 kW at 1500 rpm. Results indicated that the bioethanol–diesel emulsions exhibited a longer ignition delay by about 2.2 °CA than that of diesel operation at full load. Overall, the nitric oxide (NO and smoke emissions were found to be lesser by about 4% and 20%, respectively, with the bioethanol–diesel emulsions compared to that of diesel operation at full load. The BMDE5 emulsion gave a better performance and lower emissions compared to that of BMDE10 and BMDE15. It is suggested that the bioethanol produced from Madhuca Indica flower can be used as a potential alternative fuel replacing 5% of petroleum diesel.

  3. Emission characteristics of a turbocharged diesel engine fueled with gas-to-liquids

    Institute of Scientific and Technical Information of China (English)

    WU Tao; ZHANG Wugao; FANG Junhua; HUANG Zhen

    2007-01-01

    Emission characteristics of a turbocharged,intercooled,heavy-duty diesel engine operating on neat gas-toliquids (GTL) and blends of GTL with conventional diesel were investigated and a comparison was made with those of diesel fuel.The results show that nitrogen oxides (NOx),smoke,and particulate matter (PM) emissions can be decreased when operating on GTL and diesel-GTL blends.Engine emissions decrease with an increase of GTL fraction in the blends.Compared with diesel fuel,an engine operatingon GTL can reduce NOx,PM,carbon monoxide (CO),and hydrocarbon (HC) by 23.7%,27.6%,16.6% and 12.9% in ECE R49 13-mode procedure,respectively.Engine speed and load have great influences on emissions when operating on diesel-GTL blends and diesel fuel in the turbocharged diesel engine.The study indicates that GTL is a promisingalternative fuel for diesel engines to reduce emissions.

  4. EPDM composite membranes modified with cerium doped lead zirconate titanate

    Science.gov (United States)

    Zaharescu, T.; Dumitru, A.; Lungulescu, M. E.; Velciu, G.

    2016-01-01

    This study was performed on γ-irradiated ethylene-propylene diene terpolymer (EPDM) loaded with lead zirconate titanate. The inorganic phase has a perovskite structure with general formula Pb(Zr0.65-xCexTi0.35)O3. The three composites with different Ce dopant concentrations revealed the stabilization activity of filler against oxidation proved by chemiluminescence investigation in respect to pristine polymer. The presence of cerium low concentrations in the solid lead zirconate titanate nanoparticles causes significant slowing of oxidation rate during radiation exposure. The improvement in the stabilization feature of filler is correlated with the existence of traps, whose interaction with free radicals assumes medium energy due to their convenient depth.

  5. Laser-based diagnostics on NO in a diesel engine

    NARCIS (Netherlands)

    Brugman, Theodorus Maria

    1999-01-01

    Of all internal combustion engines diesel engines tend to be the most efficient. However, this high efficiency is coupled with specific emissions of nitric oxides (NOx = NO and NO2) and soot. Such emissions are best fought against at their very source: the diesel combustion process itself. The objec

  6. Diesel emission control: Catalytic filters for particulate removal

    Directory of Open Access Journals (Sweden)

    Debora Fino

    2007-01-01

    Full Text Available The European diesel engine industry represents a vital sector across the Continent, with more than 2 million direct work positions and a turnover of over 400 billion Euro. Diesel engines provide large paybacks to society since they are extensively used to transport goods, services and people. In recent years increasing attention has been paid to the emissions from diesel engines which, like gasoline engine emissions, include carbon monoxide (CO, hydrocarbons (HC and oxides of nitrogen (NOx. Diesel engines also produce significant levels of particulate matter (PM, which consists mostly of carbonaceous soot and a soluble organic fraction (SOF of hydrocarbons that have condensed on the soot.

  7. Development of microwave-heated diesel particulate filters

    Energy Technology Data Exchange (ETDEWEB)

    Janney, M.A.; Stinton, D.P. [Oak Ridge National Lab., TN (United States); Yonushonis, T.M.; McDonald, A.C.; Wiczynski, P.D.; Haberkamp, W.C.

    1996-06-01

    Diesel engines are a prime mover of freight in the United States. Because of legislated reductions in diesel engine emissions, considerable research has been focused on the reduction of these emissions while maintaining the durability, reliability, and fuel economy of diesel engines. The Environmental Protection Agency (EPA) has found that particulate exhaust from diesel powered vehicles represents a potential health hazard. As a result, regulations have been promulgated limiting the allowable amounts of particulate from those vehicles. The 0.1 g/bhp/hr (gram per brake horsepower per hour) particulate standard that applies to heavy-duty diesels became effective in 1994. Engine manufacturers have met those requirements with engine modifications and/or oxidation catalysts. EPA has established more stringent standards for diesel-powered urban buses because of health concerns in densely populated urban areas.

  8. Analysis of oxidation characteristics on combustion of diesel fuels with CeO2 nano-catalyst particulates%CeO2纳米颗粒催化柴油燃烧氧化特性分析

    Institute of Scientific and Technical Information of China (English)

    孟建; 刘军恒; 孙平; 冯浩杰

    2016-01-01

    Diesel particle emission is a major resource of particulate matter 2.5 (PM2.5) and is harmful to human health. Diesel particulate filter (DPF) is a principal method to reduce diesel PM emission. The DPF requires periodical regeneration by oxidizing the particulates deposited in filters to prevent plugging. The exhaust gas temperature of the diesel engine is considerably lower than the ignition temperature of diesel particulates. Adding a nano-catalyst directly to the fuel to lower the ignition temperature of the diesel particulates is a good method. CeO2 nano-catalyst is proved to oxide the soot with high catalytic activity and stability, and is considered as a promising catalyst for application in DPF. The influence of CeO2 nano-catalyst added in diesel oil on the oxidation and structure characteristics of diesel particulates was studied using thermogravimetric analysis (TGA) and scanning electron microscope (SEM) in this article. Three kinds of CeO2 nano-catalyst fuels were confected, in which CeO2mass fractions were 0, 50 and 100 mg/kg (F0, F50 and F100), respectively. The micro-orifice uniform deposition impactor (MOUDI) was used to collect the particulates generated by burning P0, P50 and P100. The SEM was used to study the influence of CeO2 mass fraction on the particle morphology characteristics. The effects of heating rates and CeO2 mass fraction on particle thermal oxidation characteristics were studied by thermogravimetric analysis method. The activation energy of particulates was calculated with Coast-Redfern integrate method. The results show that there were obvious clusters morphology of particulates from diesel engine fueled with the three CeO2 nano-catalyst fuels, and the particle distribution sizes were mainly concentrated between 20 nm and 70 nm, which were single peak curves. With the increase of CeO2 mass fraction, the particle sizes of P0, P50 and P100, the mean diameter of particulates decreased and the box dimension increased, accordingly. The

  9. Adsorbate-modified growth of ultrathin rare-earth oxide films on silicon and complementary studies of cerium oxide on ruthenium; Adsorbat-modifiziertes Wachstum ultraduenner Seltenerdoxid-Filme auf Silizium und komplementaere Studien von Ceroxid auf Ruthenium

    Energy Technology Data Exchange (ETDEWEB)

    Kaemena, Bjoern

    2013-11-27

    Rare-earth oxides (REOx) are extensively investigated due to their extraordinary physical and chemical properties, which essentially arise from the unfilled 4f electron shell, in order to reveal the nature of these exceptional properties and ultimately to utilize them for multiple technological applications. To maintain the exponential increase in integration density in CMOS technology, which is also known as Moore s law, there is a strong desire for ultrathin, well-ordered, epitaxial REOx layers with a precisely engineered interface, which is essential for reliable, ultrahigh-performance devices. So far this has been considerably impeded by RE-promoted silicon oxidation, leading to amorphous silicon oxide and RE silicon formation. By using complementary synchrotron radiation methods such as X-ray standing waves (XSW), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), structural and spectroscopic information are inferred simultaneously from ultrathin ceria and lanthana films grown on chlorine, silver and gallium passivated silicon(111). In general, it is revealed that the chemical and structural composition of the interface and the crystallinity of ultrathin REOx layers on silicon can be precisely controlled by adsorbate-mediated growth. This might represent a crucial step towards a perfectly engineered interface, eventually allowing for the integration of REOx as high-k gate oxides in microelectronics. In catalysis inverse model catalysts are studied with the aim of getting an in-depth understanding of the basic principles of catalysis. These model systems are employed to study, e. g., the nature of active sites and the reaction pathways in complex catalytic converters. However, a lot remains unknown about the chemical activity and selectivity as a function of the growth mechanism, structure and morphology of these model systems. The powerful spectroscopic photoemission and low-energy electron microscope, which is able to reveal the surface

  10. Effect of hydrogen–diesel dual-fuel usage on performance, emissions and diesel combustion in diesel engines

    Directory of Open Access Journals (Sweden)

    Yasin Karagöz

    2016-08-01

    Full Text Available Diesel engines are inevitable parts of our daily life and will be in the future. Expensive after-treatment technologies to fulfil normative legislations about the harmful tail-pipe emissions and fuel price increase in recent years created expectations from researchers for alternative fuel applications on diesel engines. This study investigates hydrogen as additive fuel in diesel engines. Hydrogen was introduced into intake manifold using gas injectors as additive fuel in gaseous form and also diesel fuel was injected into cylinder by diesel injector and used as igniter. Energy content of introduced hydrogen was set to 0%, 25% and 50% of total fuel energy, where the 0% references neat diesel operation without hydrogen injection. Test conditions were set to full load at 750, 900, 1100, 1400, 1750 and finally 2100 r/min engine speed. Variation in engine performance, emissions and combustion characteristics with hydrogen addition was investigated. Hydrogen introduction into the engine by 25% and 50% of total charge energy reveals significant decrease in smoke emissions while dramatic increase in nitrogen oxides. With increasing hydrogen content, a slight rise is observed in total unburned hydrocarbons although CO2 and CO gaseous emissions reduced considerably. Maximum in-cylinder gas pressure and rate of heat release peak values raised with hydrogen fraction.

  11. Experimental investigations on mixing of two biodiesels blended with diesel as alternative fuel for diesel engines

    Directory of Open Access Journals (Sweden)

    K. Srithar

    2017-01-01

    Full Text Available The world faces the crises of energy demand, rising petroleum prices and depletion of fossil fuel resources. Biodiesel has obtained from vegetable oils that have been considered as a promising alternate fuel. The researches regarding blend of diesel and single biodiesel have been done already. Very few works have been done with the combination of two different biodiesel blends with diesel and left a lot of scope in this area. The present study brings out an experiment of two biodiesels from pongamia pinnata oil and mustard oil and they are blended with diesel at various mixing ratios. The effects of dual biodiesel works in engine and exhaust emissions were examined in a single cylinder, direct injection, air cooled and high speed diesel engine at various engine loads with constant engine speed of 3000 rpm. The influences of blends on CO, CO2, HC, NOx and smoke opacity were investigated by emission tests. The brake thermal efficiency of blend A was found higher than diesel. The emissions of smoke, hydro carbon and nitrogen oxides of dual biodiesel blends were higher than that of diesel. But the exhaust gas temperature for dual biodiesel blends was lower than diesel.

  12. Catalytic activity of cerium-doped Ru/Al2O3 during ozonation of dimethyl phthalate

    Institute of Scientific and Technical Information of China (English)

    Yunrui ZHOU; Wanpeng ZHU; Xun CHEN

    2008-01-01

    In this paper, factors influencing the mineraliza-tion of dimethyl phthalate (DMP) during catalytic ozona-tion with a cerium-doped Ru/Al2O3 catalyst were studied. The catalytic contribution was calculated through the results of a companrison experiment. It showed that doping cerium significantly enhanced catalytic activity. The total organic carbon (TOC) removal over the doped catalyst at 100 rain reached 75.1%, 61.3% using Ru/Al2O3 catalyst and only 14.0% using ozone alone. Catalytic activity reached the maximum when 0.2% of ruthenium and 1.0% of cerium'were simultaneously loaded onto Al2O3 support. Results of experiments on oxidation by ozone alone, adsorption of the catalyst, Ce ion's and heterogeneous catalytic ozonation confirmed that the contribution of het-erogeneous catalytic ozonation was about 50%, which showed the obvious effect of Ru-Ce/Al2O3 on catalytic activity.

  13. Oxidative Stress, Inflammatory Biomarkers and Toxicity in Mouse Lung and Liver after Inhalation Exposure to 100% Biodiesel or Petroleum Diesel Emissions

    Science.gov (United States)

    BACKGROUND: Over the past decade, biodiesel (BD) has become a first alternative energy source that is economically viable and meets requirements of the Clean Air Act. Due to lower mass emissions and reduced hazardous compounds compared to diesel combustion emissions (CE), BD expo...

  14. Dual fuel diesel engine operation using LPG

    Science.gov (United States)

    Mirica, I.; Pana, C.; Negurescu, N.; Cernat, Al; Nutu, N. C.

    2016-08-01

    Diesel engine fuelling with LPG represents a good solution to reduce the pollutant emissions and to improve its energetic performances. The high autoignition endurance of LPG requires specialized fuelling methods. From all possible LPG fuelling methods the authors chose the diesel-gas method because of the following reasons: is easy to be implemented even at already in use engines; the engine does not need important modifications; the LPG-air mixture has a high homogeneity with favorable influences over the combustion efficiency and over the level of the pollutant emissions, especially on the nitrogen oxides emissions. This paper presents results of the theoretical and experimental investigations on operation of a LPG fuelled heavy duty diesel engine at two operating regimens, 40% and 55%. For 55% engine load is also presented the exhaust gas recirculation influence on the pollutant emission level. Was determined the influence of the diesel fuel with LPG substitution ratio on the combustion parameters (rate of heat released, combustion duration, maximum pressure, maximum pressure rise rate), on the energetic parameters (indicate mean effective pressure, effective efficiency, energetic specific fuel consumption) and on the pollutant emissions level. Therefore with increasing substitute ratio of the diesel fuel with LPG are obtained the following results: the increase of the engine efficiency, the decrease of the specific energetic consumption, the increase of the maximum pressure and of the maximum pressure rise rate (considered as criteria to establish the optimum substitute ratio), the accentuated reduction of the nitrogen oxides emissions level.

  15. Cerium oxide as a promoter for the electro-oxidation reaction of ethanol: in situ XAFS characterization of the Pt nanoparticles supported on CeO2 nanoparticles and nanorods.

    Science.gov (United States)

    Corchado-García, Juan; Betancourt, Luis E; Vélez, Carlos A; Senanayake, Sanjaya D; Stacchiola, Dario; Sasaki, Kotaro; Guinel, Maxime J-F; Zhou, Yunyun; Cheung, Chin Li; Cabrera, Carlos R

    2015-12-28

    In this study we probe the electrocatalytic activity of Pt nanoparticles supported on ceria nanoparticles (NPs) and nanorods (NRs) in the ethanol oxidation reaction (EOR) in alkaline media. The goal of this study was to relate morphology, support structure and composition to the EOR catalytic activity by using in situ X-ray absorption fine structure (XAFS) studies. Cyclic voltammetry experiments showed that both ceria supported catalysts (NP vs. NR) had similar peak current densities at fast scan rates, however at slow scan rates, the ceria NR catalyst showed superior catalytic activity. In situ XAFS studies in KOH showed that both ceria supported catalysts had more electron density in their d-band (with the ceria NR having more electron density overall) than ceria - free Pt/Vulcan standard. However, in an ethanol solution the ceria NR catalyst had the least electron density. We propose that this change is due to the increased charge transfer efficiency between the ceria nanorod support and platinum. In the KOH solution, the increased electron density makes the platinum less electrophilic and hinders Pt-OH bond formation. In the EtOH solution, platinum's increased nucleophilicity facilitates the bond formation between Pt and the electron deficient carbon in ethanol which in turn withdraws the electron density from platinum and increases the white line intensity as observed in the XAS measurements.

  16. IMPACT OF OXYGENATED FUEL ON DIESEL ENGINE PERFORMANCE AND EMISSIONS

    Energy Technology Data Exchange (ETDEWEB)

    Boehman, Andre L.

    2000-08-20

    As evidenced by recent lawsuits brought against operators of large diesel truck fleets [1] and by the Consent Decree brought against the heavy-duty diesel manufacturers [2], the environmental and health effects of diesel engine emissions continue to be a significant concern. Reduction of diesel engine emissions has traditionally been achieved through a combination of fuel system, combustion chamber, and engine control modifications [3]. Catalytic aftertreatment has become common on modern diesel vehicles, with the predominant device being the diesel oxidation catalytic converter [3]. To enable advanced after-treatment devices and to directly reduce emissions, significant recent interest has focused on reformulation of diesel fuel, particularly the reduction of sulfur content. The EPA has man-dated that diesel fuel will have only 15 ppm sulfur content by 2007, with current diesel specifications requiring around 300 ppm [4]. Reduction of sulfur will permit sulfur-sensitive aftertreatment devices, continuously regenerating particulate traps, NOx control catalysts, and plasma assisted catalysts to be implemented on diesel vehicles [4]. Another method of reformulating diesel fuel to reduce emissions is to incorporate oxygen in the fuel, as was done in the reformulation of gasoline. The use of methyl tertiary butyl ether (MTBE) in reformulated gasoline has resulted in contamination of water resources across the country [5]. Nonetheless, by relying on the lessons learned from MTBE, oxygenation of diesel fuel may be accomplished without compromising water quality. Oxygenation of diesel fuel offers the possibility of reducing particulate matter emissions significantly, even for the current fleet of diesel vehicles. The mechanism by which oxygen content leads to particulate matter reductions is still under debate, but recent evidence shows clearly that ''smokeless'' engine operation is possible when the oxygen content of diesel fuel reaches roughly 38% by

  17. Synthesis of Cerium-Doped Titania Nanoparticles and Nanotubes.

    Science.gov (United States)

    Cao, Wei; Suzuki, Takuya; Elsayed-Ali, Hani E; Abdel-Fattah, Tarek M

    2015-03-01

    Cerium-doped titania nanoparticles and nanotubes were synthesized via hydrothermal processes. X-Ray Diffraction revealed that cerium-doped titania nanoparticles have an anatase crystal structure, while cerium-doped titania nanotubes have an H2Ti3O7-type structure. Scanning electron microscopy and high resolution transmission electron microscopy showed that both types of titania are well crystallized with relatively uniform size distribution. The photocatalytic degradation of methylthioninium chloride known as methylene blue dye was tested and both cerium-doped titania nanoparticles and nanotubes. The preliminary photocatalytic degradation of Methylene Blue data showed significantly improved visible light photocatalytic activities as compared to commercial titania powders.

  18. Reduction of nitrogen oxide emission from maritime diesel engines in common rail operation; Reduzierung der Stickoxidemission von Schiffsdieselmotoren im Common-Rail-Betrieb

    Energy Technology Data Exchange (ETDEWEB)

    Fink, Christian [Rostock Univ. (Germany). Lehrstuhl fuer Kolbenmaschinen und Verbrennungsmotoren; Frobenius, Moritz [AVL Deutschland GmbH, Muenchen (Germany); Pittermann, Roland [WTZ Rosslau gGmbH, Dessau-Rosslau (Germany); Schlemmer-Kelling, Udo [Caterpillar GmbH und Co. KG, Kiel (Germany); Schneider, Hartmut [L' Orange GmbH, Stuttgart (Germany)

    2009-11-15

    In the framework of the joint EMI-MINI II project, research activities on how to meet the future IMO limits for maritime diesel engines have been performed over a period of 3 years. A reduction of NO{sub x} emission by approximately 40 % could be reached by a combination of the Miller cycle with the common rail injection technology, while keeping the efficiency factor constant and an acceptable smoke behaviour. (orig.)

  19. Deposition of cerium contained conversion films on LC4 alloy with square wave pulse method

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; LI Jiuqing; WU Yinshun; ZHANG Pei; HE Jianping

    2004-01-01

    Cerium contained conversion films were deposited on LC4 aluminum alloy using square wave pulse (SWP) in a CeC13 solution with KMnO4 as the oxidant. Energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM) were adopted to study the composition and the morphology of the film. It is found that the film is composed of Al, Zn, Cu,and small amount of cerium. The polarization curves of the specimens treated with SWP technique measured in 3.5% (mass fraction) NaCl solution reveal that the film thus formed inhibits both the anodic and cathodic process of the corrosion of the specimen. The immersion tests of treated specimens in 3.5% NaCl solution indicate that the corrosion resistance of the SWP treated specimen is better than that of the untreated and is equivalent to or even better than that of the traditionally electrochemically treated specimens.

  20. Diesel particulate filter design simulation: A review

    Directory of Open Access Journals (Sweden)

    Shichun Yang

    2016-03-01

    Full Text Available Simulation is a powerful tool in the design and analysis of diesel particulate filters. Various models have been developed in the last three decades and great improvements have been made in terms of model comprehensiveness and accuracy. However, simulation of diesel particulate filter is still not a reliable resort to fine-tuning of diesel particulate filter and much effort is still needed. To promote the development of effective simulation models, first, the various models are viewed. Their characteristics and application occasions are discussed. Second, regarding the limitations of these models, some key submodels are introduced, which are pressure drop model in the wall, filtration model, and soot oxidation model. Finally, some conclusions are made and further researches are recommended.

  1. Thermochemical Modeling of the Uranium-Cerium-Oxygen System

    Energy Technology Data Exchange (ETDEWEB)

    Voit, Stewart L [ORNL; Besmann, Theodore M [ORNL

    2010-10-01

    The objective of the Fuel Cycle R&D Program, Advanced Fuels campaign is to provide the research and development necessary to develop low loss, high quality nuclear fuels for ultra-high burnup reactor operation. Primary work in this area will be focused on the ceramic and metallic fuel systems. The goal of the current work is to enhance the understanding of ceramic nuclear fuel thermochemistry to support fuel research and development efforts. The thermochemical behavior of oxide nuclear fuel under irradiation is dependent on the oxygen to metal ratio (O:M). In fluorite-structured fuel, the actinide metal cation is bonded with {approx}2 oxygen atoms on a crystal lattice and as the metal atoms fission, fission fragments and free oxygen are created. The resulting fission fragments will contain some oxide forming elements, however these are insufficient to bind to all the liberated oxygen and therefore, there is an average increase in O:M with fuel burnup. Some of the fission products also form species that will migrate to and react with the cladding surface in a phenomenon known as Fuel Clad Chemical Interaction (FCCI). Cladding corrosion is life-limiting so it is desirable to understand influencing factors, such as oxide thermochemistry, which can be used to guide the design and fabrication of higher burn up fuel. A phased oxide fuel thermochemical model development effort is underway within the Advanced Fuels Campaign. First models of binary oxide systems are developed. For nuclear fuel system this means U-O and transuranic systems such as Pu-O, Np-O and Am-O. Next, the binary systems will be combined to form pseudobinary systems such as U-Pu-O, etc. The model development effort requires the use of data to allow optimization based on known thermochemical parameters as a function of composition and temperature. Available data is mined from the literature and supplemented by experimental work as needed. Due to the difficulty of performing fuel fabrication development

  2. Recovery of Cerium Dioxide from Spent Glass-Polishing Slurry and Its Utilization as a Reactive Sorbent for Fast Degradation of Toxic Organophosphates

    Directory of Open Access Journals (Sweden)

    Pavel Janoš

    2015-01-01

    Full Text Available The recovery of cerium (and possibly other rare earth elements from the spent glass-polishing slurries is rather difficult because of a high resistance of polishing-grade cerium oxide toward common digestion agents. It was shown that cerium may be extracted from the spent polishing slurries by leaching with strong mineral acids in the presence of reducing agents; the solution may be used directly for the preparation of a ceria-based reactive sorbent. A mixture of concentrated nitric acid and hydrogen peroxide was effective in the digestion of partially dewatered glass-polishing slurry. After the removal of undissolved particles, cerous carbonate was precipitated by gaseous NH3 and CO2. Cerium oxide was prepared by a thermal decomposition of the carbonate precursor in an open crucible and tested as reactive sorbent for the degradation of highly toxic organophosphate compounds. The samples annealed at the optimal temperature of approximately 400°C exhibited a good degradation efficiency toward the organophosphate pesticide fenchlorphos and the nerve agents soman and VX. The extraction/precipitation procedure recovers approximately 70% of cerium oxide from the spent polishing slurry. The presence of minor amounts of lanthanum does not disturb the degradation efficiency.

  3. Fabrication of ultra-thin cerium oxide layers on Ru(0001) single crystal surfaces. Scanning tunneling microscopic and photoelectron spectroscopic studies on growth, structure and properties; Herstellung ultraduenner Ceroxidschichten auf Ru(0001)-Einkristallflaechen. Rastertunnelmikroskopische und photoelektronenspektroskopische Untersuchungen zu Wachstum, Struktur und Eigenschaften

    Energy Technology Data Exchange (ETDEWEB)

    Bouchtaoui, Mustapha

    2016-12-07

    The thesis at hand aims at a study of structure and properties of well-defined ultrathin CeO{sub 2} films supported on Ru(0001). Such systems may serve as model systems in heterogenous catalysis. The epitaxial growth of ceria films on Ru(0001) surface has been achieved by electron beam evaporation of metal Cer at low background oxygen pressure of 10{sup -6} mbar under ultrahigh-vacuum conditions at room temperature. Cerium oxide qualifies for proper oxygen-storage in oxidation reactions, and hence it widely used in heterogenous catalysis. The oxidation begins with the adsorption of CO on the CeO{sub 2}(111) surface, and it ends with participation of lattice oxygen leading to vacancy formation and CO{sub 2} desorption. We investigate the geometric structure by means of scanning tunneling microscopy and low energy electron diffraction. The coverage of 2.5 monolayers (ML) was sufficient to cover the substrate almost completely. We further analysed the interaction of CO with the CeO{sub 2}/Ru(0001) and the Pt/CeO{sub 2}/Ru(0001) systems. During the interaction process the ratio of Ce{sup 4+} and Ce{sup 3+} changes significantly. This ratio change as well as the effect of Pt evaporated onto the surface with respect to the reducibility of CeO{sub 2}/Ru(0001) in CO environment has been studied by X-ray photoemission spectroscopy and it has been confirmed with thermal desorption spectroscopy. It is revealed that the Pt-Nanoparticles with a height from 7.15 Aa to 9.73 Aa clearly enhances the reducibility of CeO{sub 2}.

  4. Particulate matters from diesel engine exhaust emission

    Directory of Open Access Journals (Sweden)

    Petrović Velimir S.

    2008-01-01

    Full Text Available Air pollution caused by diesel engine emissions, especially particulate matters and nitric oxides emissions, is one of the biggest problems of current transportation. In the near future the emission of diesel particulate matters will become one of the most important factors that will affect the trend of engine development. Ambient airborne particles have adverse environmental and health effects and therefore their concentration in the air is regulated. Recent medical studies showed that different particle properties are important (for example: number/concentration, active surface, chemical composition/morphology and may take role in the responsibility for their human health impact. Thus, diesel engines are one of the most important sources of particles in the atmosphere, especially in urban areas. Studying health effects and diesel engine particulate properties, it has been concluded that they are a complex mixture of solids and liquids. Biological activity of particulate matter may be related to particle sizes and their number. The paper presents the activities of UN-ECE working group PMP on defining the best procedure and methodology for the measurement of passenger cars diesel engines particle mass and number concentrations. The results of inter-laboratory emissions testing are presented for different engine technologies with special attention on repeatability and reproducibility of measured data. .

  5. Thermodynamics of congruently subliming cerium-antimony

    Energy Technology Data Exchange (ETDEWEB)

    Schiffman, R.A.; Franzen, H.F.

    1982-01-01

    Congruently vaporizing cerium-antimony has been investigated by vapor pressure measurementa using a simultaneous weight-loss mass-spectrometric Knudsen effusion technique. The melting point of the 1:1 stoichiometry was determined to be 2179 +/- 10 K. The heat of formation at 298 K of CeSb was found to be -128.9 kJ/g-at from thermodynamic measurements in the temperature range 1985-2172 K.

  6. Evaluation of the Use of Ultra Low Sulfur Diesel Oil for an Emergency Diesel Generator

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Young-Chul; Chung, Woo-Geun [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    The aim of this study is to assess the compatibility and effect on driving an emergency diesel generator using ULSD examining the specific gravity and lubricity of the oil. Because generators at NPPs use ULSD which is not mostly used for medium-large diesel generator engines, this study seeks to provide effective precautions for the driving stability of emergency diesel generators. One of the major fuel oils used in medium-large diesel engines for the normal driving of vessels and the generation of emergency power at power plants is heavy fuel oil. There are no vessels and power generation engines known to use high-quality diesel oil which is widely used in cars. The findings of this study suggest that when driving a diesel generator, there will be increased fuel consumption by 3.6% [m{sup 3}/hr.]. Furthermore, the mechanical fuel limiter on the engine needs an upward adjustment because the system is set for 110% load operations for the former LSD fuel. Both LSD and ULSD retain lubricity with a WSD around 330~350μm. These results clearly show that bad lubricity problems are not expected to occur. We had presumed an increased amount of foreign particulates because of the increased additives for high lubricity and oxidative stability.

  7. Emissions of Transport Refrigeration Units with CARB Diesel, Gas-to-Liquid Diesel, and Emissions Control Devices

    Energy Technology Data Exchange (ETDEWEB)

    Barnitt, R. A.; Chernich, D.; Burnitzki, M.; Oshinuga, A.; Miyasato, M.; Lucht, E.; van der Merwe, D.; Schaberg, P.

    2010-05-01

    A novel in situ method was used to measure emissions and fuel consumption of transport refrigeration units (TRUs). The test matrix included two fuels, two exhaust configurations, and two TRU engine operating speeds. Test fuels were California ultra low sulfur diesel and gas-to-liquid (GTL) diesel. Exhaust configurations were a stock muffler and a Thermo King pDPF diesel particulate filter. The TRU engine operating speeds were high and low, controlled by the TRU user interface. Results indicate that GTL diesel fuel reduces all regulated emissions at high and low engine speeds. Application of a Thermo King pDPF reduced regulated emissions, sometimes almost entirely. The application of both GTL diesel and a Thermo King pDPF reduced regulated emissions at high engine speed, but showed an increase in oxides of nitrogen at low engine speed.

  8. Analysis of single and binary phases in cerium doped sodium bismuth titanate -inorganic materials Na{sub 0}.5Bi{sub (}0.5-x)Ce{sub x}TiO{sub 3}; Estudio de fases simples y binarias en BNT puro y dopado con cerio Na{sub 0},5Bi{sub (}0,5-x)Ce{sub x}TiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Supriya, S.; Dos Santos-Garcia, A. J.; Frutos, J. de; Fernandez-Martinez, F.

    2015-07-01

    The pure and cerium doped sodium bismuth titanate (NBT) inorganic powders were synthesized by solid-state reaction method. The presence of rhombohedral phase was observed in cerium doped NBT compounds. When x= 0.05 of cerium doped NBT is heat treated at 1200 degree centigrade, the compound forms single perovskite phase. The samples of x = 0.10 and 0.15 were heat treated up to 1350 degree centigrade, the binary phases with cerium and bismuth oxides were observed. The X-ray diffraction, Fourier transform infrared spectroscopy, reflectance spectra, differential thermal analysis and thermogravimetric analysis were used to analyze the various properties of samples. Moreover, the effects of cerium doping and calcining temperature on NBT samples were investigated. In this work, we present our recent results on the synthesis and characterization of cerium doped sodium bismuth titanate materials. (Author)

  9. Improvement of thermal effciency in diesel engine. Diesel engine no koritsu kojo

    Energy Technology Data Exchange (ETDEWEB)

    Kawamura, H. (Isuzu Ceramics Research Inst. Co. Ltd., Kanagawa, (Japan))

    1993-04-05

    Diesel engines cause worsening air pollution due to much more discharge of nitrogen oxides than gasoline engines, however for reduction of carbon dioxide, Diesel engines consuming less fuel are better than gasoline engines for protection of the global environment. Theoretical thermal efficiency is larger as compression ratio and isochronic burnup are bigger, hence such an engine is needed that is made on the basis of a Diesel engine, whose compression ratio is twice or more larger than that of gasoline engine and which has good thermal efficiency, and reduces its nitrogen oxides by the development of the combustion technique by means of controlling combustion temperature as well as fuel equivalent ratio. With regard to the improvement of thermal efficiency of Diesel engines, it can be attained, utilizing the respective features of the antechamber-type and the direct injection-type Diesels, by burning the homogeneous mixture, whose fuel equivalent ratio is big, in the initial stage and by controlling the main combustion period in the main chamber short. inaddition, a radiation shield-type turbocompound engine has been test fabricated and rough explanations are given on its structure, its combustion and the recovery of its exhaust gas energy. 5 refs., 6 figs., 1 tab.

  10. Water-in-diesel emulsions and related systems.

    Science.gov (United States)

    Lif, Anna; Holmberg, Krister

    2006-11-16

    Water-in-diesel emulsions are fuels for regular diesel engines. The advantages of an emulsion fuel are reductions in the emissions of nitrogen oxides and particulate matters, which are both health hazardous, and reduction in fuel consumption due to better burning efficiency. An important aspect is that diesel emulsions can be used without engine modifications. This review presents the influence of water on the emissions and on the combustion efficiency. Whereas there is a decrease in emissions of nitrogen oxides and particulate matters, there is an increase in the emissions of hydrocarbons and carbon monoxide with increasing water content of the emulsion. The combustion efficiency is improved when water is emulsified with diesel. This is a consequence of the microexplosions, which facilitate atomization of the fuel. The review also covers related fuels, such as diesel-in-water-in-diesel emulsions, i.e., double emulsions, water-in-diesel microemulsions, and water-in-vegetable oil emulsions, i.e., biodiesel emulsions. A brief overview of other types of alternative fuels is also included.

  11. Activated carbon use in treating diesel engine exhausts

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, S.G.; Babyak, R.A. [Sorbent Technologies Corp., Twinsburg, OH (United States)

    1996-10-01

    Several active carbon materials were observed to be particularly effective in processes for the removal of nitrogen oxides from exhaust gases. This paper describes the application of active carbon materials to two diesel engine exhaust gases at McClellan AFB in California. More specifically, one application involved a large diesel engine that supplies emergency power at the Base, and the second involved a mobile diesel-fueled generator that provides auxiliary power to aircraft. The designs of systems to control emissions for each application are discussed, and the results of tests on laboratory-scale, pilot-scale, and full-scale systems are presented.

  12. The use of urea to combat nitrogen oxides; Selective catalytic denitrification of Diesel emissions. Mit Harnstoff gegen Stickoxide; Selektive katalytische Entstickung von Dieselabgasen

    Energy Technology Data Exchange (ETDEWEB)

    Koebel, M.; Elsener, M.; Eicher, H. (Paul Scherrer Inst. (PSI), Villigen (Switzerland))

    1990-01-01

    Reports available deal with efforts to denitrify Diesel emissions by the use of urea instead of ammonia and applying an SCT (selective catalytic reduction) process. These efforts are pursued in a common project carried out by the Paul Scherrer Institute and the Eicher + Pauli AG, and promoted by the Federal Office of Energy. The Paul Scherrer Institute is dedicated mainly to basic research, and technique of analyzing and laboratory work, while Eicher + Pauli AG are responsible for the construction and operation of the pilot plant.

  13. Bio-Diesel production and Effect of Catalytic Converter on Emission performance with Bio-Diesel Blends

    Directory of Open Access Journals (Sweden)

    R.Murali Manohar

    2010-06-01

    Full Text Available Bio-Diesel the word itself defines almost all the features of the Bio-Diesel literary. In the Era of this Global Warming where the people are making their living more and more comfortable and they are deteriorating the environment also. The uses of the automobiles with the conventional source of fuel leads to the production of the toxic gaseous substances like carbon monoxide, carbon dioxide, oxides of nitrogen, oxide of sulphur, hydro-carbons etc. The limitation comes with the rise in the price of the fuel as well as the produce of the green house gases as the exhaust gas. In the present study, a new method has been employed to produce Bio-Diesel in a homely basis. Theproduction of the Bio-Diesel is done by using Bio-Diesel processor. It requires the used vegetable oil, methanol and the lye with the accurate proportionate. Generally, emissions of regulated compounds changed linearly with the blend level. The objective is to detect any posit ive or negative effects depending on blend levels, because conventional diesel fuel and biodiesel can be blended in every ratio. The known positive and negative effects of biodiesel varied accordingly and investigate the effect of Catalytic Converter on emission performance with Bio- Diesel Blends.

  14. Cerium Biomagnification in a Terrestrial Food Chain: Influence of Particle Size and Growth Stage.

    Science.gov (United States)

    Majumdar, Sanghamitra; Trujillo-Reyes, Jesica; Hernandez-Viezcas, Jose A; White, Jason C; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L

    2016-07-01

    Mass-flow modeling of engineered nanomaterials (ENMs) indicates that a major fraction of released particles partition into soils and sediments. This has aggravated the risk of contaminating agricultural fields, potentially threatening associated food webs. To assess possible ENM trophic transfer, cerium accumulation from cerium oxide nanoparticles (nano-CeO2) and their bulk equivalent (bulk-CeO2) was investigated in producers and consumers from a terrestrial food chain. Kidney bean plants (Phaseolus vulgaris var. red hawk) grown in soil contaminated with 1000-2000 mg/kg nano-CeO2 or 1000 mg/kg bulk-CeO2 were presented to Mexican bean beetles (Epilachna varivestis), which were then consumed by spined soldier bugs (Podisus maculiventris). Cerium accumulation in plant and insects was independent of particle size. After 36 days of exposure to 1000 mg/kg nano- and bulk-CeO2, roots accumulated 26 and 19 μg/g Ce, respectively, and translocated 1.02 and 1.3 μg/g Ce, respectively, to shoots. The beetle larvae feeding on nano-CeO2 exposed leaves accumulated low levels of Ce since ∼98% of Ce was excreted in contrast to bulk-CeO2. However, in nano-CeO2 exposed adults, Ce in tissues was higher than Ce excreted. Additionally, Ce content in tissues was biomagnified by a factor of 5.3 from the plants to adult beetles and further to bugs.

  15. Stability and filtering capacity of diesel oil; Estabilidade e filtrabilidade do oleo diesel

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Marcelo Vieira; Rocha, Mauro Iurk [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES). Gerencia de Combustiveis]. E-mails: marvial@petrobras.com.br; miurk@petrobras.com.br; Zotin, Fatima Maria Zanon [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Inst. de Quimica]. E-mail: fzotin@uerj.br; Pinto, Ricardo Rodrigues da Cunha [PETROBRAS, Rio de Janeiro, RJ (Brazil). Recursos Humanos. Gerencia de Escola de Ciencias e Tecnologias]. E-mail: rcp@petrobras.com.br

    2006-12-15

    The increasing demand for the reduction in the emission of polluting agents by diesel motors has led to the use of more advanced injection systems. These systems are increasingly reducing clearances and portray more restrictive filtering capacity, protecting them from the release of fuel particles. Those particles may originate in the degradation of oil products, formed by the acid-catalyzed condensation between aromatic compounds and heterocyclic nitrogens. These compounds appear in the various chains used in the composition of the fuel. We address here the aspects influencing the stability to oxidation and fuel filterability as well as the methods used to assess the degradation capacity of several diesel oil formulations. (author)

  16. Cobalt, titanium or cerium oxide protective coatings for the nickel cathode of the molten carbonate fuel cells; Revetements protecteurs a base d'oxyde de cobalt, de titane ou de cerium pour la cathode de nickel des piles a combustible a carbonates fondus

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza Blanco, L.

    2003-10-15

    The aim of this work is to combine the MCFC cathode Li{sub x}Ni{sub 1-x}O properties to those of the protective coatings of LiCoO{sub 2}, Li{sub 2}TiO{sub 3} or of CeO{sub 2}, less soluble in the molten carbonates. In the cases of LiCoO{sub 2}, have been carried out by controlled potential coulometry in aqueous solution, a deposition of Co{sub 3}O{sub 4} on dense Ni. The cobalt oxide reacts rapidly in the Li{sub 2}CO{sub 3}-Na{sub 2}CO{sub 3} medium at 650 C to give LiCoO{sub 2}, a spinel cubic phase revealed by Raman spectroscopy. (O.M.)

  17. Diesel fuel stability; Estabilidade de oleo diesel

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Marcelo V.; Pinto, Ricardo R.C. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Zotin, Fatima M.Z. [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)

    2008-07-01

    The demand for the reduction of the pollutants emissions by diesel engines has led to the adoption of more advanced injection systems and concern about fuel stability. The degradation of the diesel fuel can happen during storage and distribution, according to the acid-catalysed condensation of aromatic compounds such phenalenones and indolic nitrogenated heterocyclic compounds. These precursors appear in several streams used in diesel fuel formulation. In this study the sediment formation in model and real, aromatic and paraffinic fuels, containing such precursors naturally or by addition was analysed. The fuels were submitted to accelerated (16 hours at 90 deg C) and long term (13 weeks at 43 deg C) storage stability tests. The model fuels responded positively to the storage stability tests with formation of sediments, concluding that these methods can be considered adequate to verify the occurrence of the studied degradation process. The real fuels response was even more due to their chemical complexity, composition and impurities. The formation of sediments showed to be affected by the hydrocarbon distribution of the fuels. (author)

  18. Mastering the diesel process

    Energy Technology Data Exchange (ETDEWEB)

    Antila, E.; Kaario, O.; Lahtinen, T. (and others)

    2004-07-01

    This is the final report of the research project 'Mastering the Diesel Process'. The project has been a joint research effort of the Helsinki University of Technology, the Tampere University of Technology, the Technical Research Centre of Finland, and the Aabo Akademi University. Moreover, the contribution of the Michigan Technological University has been important. The project 'Mastering the Diesel Process' has been a computational research project on the physical phenomena of diesel combustion. The theoretical basis of the project lies on computational fluid dynamics. Various submodels for computational fluid dynamics have been developed or tested within engine simulation. Various model combinations in three diesel engines of different sizes have been studied. The most important submodels comprise fuel spray drop breakup, fuel evaporation, gas-fuel interaction in the spray, mixing model of combustion, heat transfer, emission mechanisms. The boundary conditions and flow field modelling have been studied, as well. The main simulation tool have been Star-CD. KIVA code have been used in the model development, as well. By the help of simulation, we are able to investigate the effect of various design parameters or operational parameters on diesel combustion and emission formation. (orig.)

  19. Cerium-tannic acid passivation treatment on galvamzed steel

    Institute of Scientific and Technical Information of China (English)

    LIU Guangming; YU Fei; YANG Liu; TIAN Jihong; DU Nan

    2009-01-01

    A novel cerium-tannic acid passivation treatment was performed on galvanized steel. The corrosion resistance of cerium-tannic passivated samples was tested by dropping test with 0.5 wt.% CuSO4 aqueous solution. The mass loss per unit area of passivated samples was measured after the corrosion in 0.5 mol/L NaCl + 0.005 mol/L H2SO4 at room temperature for 96 h. The electrochemical behaviors of cerium, tannic acid, and cerium-tannic acid passivated samples on galvanized steel in 0.5 mol/L NaCI solution were investigated by polarization curves and electrochemical impendence spectra. The corrosion equivalent circuit was established according to the impedance characteristics. The results show that cerium-tannic acid treated samples exhibit better corrosion resistance than the sole cerium or tannic acid treated samples under the same condition. The mechanism of synergistic effect for cerium-tannic acid passivation on galvanized steel was discussed.

  20. Oxidative stress, genotoxicity, and vascular cell adhesion molecule expression in cells exposed to particulate matter from combustion of conventional diesel and methyl ester biodiesel blends

    DEFF Research Database (Denmark)

    Hemmingsen, Jette Gjerke; Møller, Peter; Nøjgaard, Jacob Klenø;

    2011-01-01

    Our aim was to compare hazards of particles from combustion of biodiesel blends and conventional diesel (D(100)) in old and improved engines. We determined DNA damage in A549 cells, mRNA levels of CCL2 and IL8 in THP-1 cells, and expression of ICAM-1 and VCAM-1 in human umbilical cord endothelial...... cells (HUVECs). Viability and production of reactive oxygen species (ROS) were investigated in all cell types. We collected particles from combustion of D(100) and 20% (w/w) blends of animal fat or rapeseed oil methyl esters in light-duty vehicle engines complying with Euro2 or Euro4 standards....... Particles emitted from the Euro4 engine were smaller in size and more potent than particles emitted from the Euro2 engine with respect to ROS production and DNA damage, but similarly potent concerning cytokine mRNA expression. Particles emitted from combustion of biodiesel blends were larger in size...

  1. Increased luminescence and improved decay kinetics in lithium and cerium co-doped yttrium aluminum garnet scintillators grown by the Czochralski method

    Science.gov (United States)

    Dickens, Peter T.; Haven, Drew T.; Friedrich, Stephan; Saleh, Muad; Lynn, Kelvin G.

    2017-03-01

    In this study, four yttrium aluminum garnet single crystals co-doped with cerium and lithium were produced by the Czochralski method and the scintillation and defect properties were investigated. Our results demonstrated an increase in luminescence with Li co-doping as well as elimination of longer decay times. Surprisingly, although Li is monovalent, no oxidation of cerium from Ce3+ to Ce4+ was found as would be expected to maintain charge neutrality. Additionally, thermoluminescence results indicated a reduction in the trapping of charge carriers by shallow and deep traps, and room temperature photoluminescence measuremen