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Sample records for cerium oxide diesel

  1. Brain suppression of AP-1 by inhaled diesel exhaust and reversal by cerium oxide nanoparticles

    NARCIS (Netherlands)

    Lung, Shyang; Cassee, Flemming R; Gosens, Ilse; Campbell, Arezoo

    One of the uses of cerium oxide nanoparticles (nanoceria, CeO2) is as a diesel fuel additive to improve fuel efficiency. Gene/environment interactions are important determinants in the etiology of age-related disorders. Thus, it is possible that individuals on high-fat diet and genetic

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

    Science.gov (United States)

    Snow, Samantha J.; McGee, John; Miller, Desinia B.; Bass, Virginia; Schladweiler, Mette C.; Thomas, Ronald F.; Krantz, Todd; King, Charly; Ledbetter, Allen D.; Richards, Judy; Weinstein, Jason P.; Conner, Teri; Willis, Robert; Linak, William P.; Nash, David; Wood, Charles E.; Elmore, Susan A.; Morrison, James P.; Johnson, Crystal L.; Gilmour, Matthew Ian; Kodavanti, Urmila P.

    2014-01-01

    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 results in greater adverse pulmonary effects compared with DE. Male Sprague Dawley rats were exposed to filtered air, DE, or DECe for 5 h/day for 2 days. N-acetyl glucosaminidase activity was increased in bronchial alveolar lavage fluid (BALF) of rats exposed to DECe but not DE. There were also marginal but insignificant increases in several other lung injury biomarkers in both exposure groups (DECe > DE for all). To further characterize DECe toxicity, rats in a second study were exposed to filtered air or DECe for 5 h/day for 2 days or 4 weeks. Tissue analysis indicated a concentration- and time-dependent accumulation of lung and liver cerium followed by a delayed clearance. The gas-phase and high concentration of DECe increased lung inflammation at the 2-day time point, indicating that gas-phase components, in addition to particles, contribute to pulmonary toxicity. This effect was reduced at 4 weeks except for a sustained increase in BALF γ-glutamyl transferase activity. Histopathology and transmission electron microscopy revealed increased alveolar septa thickness due to edema and increased numbers of pigmented macrophages after DECe exposure. Collectively, these findings indicate that DECe induces more adverse pulmonary effects on a mass basis than DE. In addition, lung accumulation of cerium, systemic translocation to the liver, and delayed clearance are added concerns to existing health effects of DECe. PMID:25239632

  3. Atomic layer deposition of cerium oxide for potential use in diesel soot combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ivanova, Tatiana V., E-mail: tatiana.ivanova@lut.fi, E-mail: ivanova.tatyana.v@gmail.com; Toivonen, Jenni; Maydannik, Philipp S.; Kääriäinen, Tommi; Sillanpää, Mika [ASTRaL Team, Laboratory of Green Chemistry, School of Engineering Science, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Homola, Tomáš; Cameron, David C. [R& D Centre for Low-Cost Plasma and Nanotechnology Surface Modification, Masaryk University, Kotlářská 267/2, 611 37 Brno (Czech Republic)

    2016-05-15

    The particulate soot emission from diesel motors has a severe impact on the environment and people's health. The use of catalytic convertors is one of the ways to minimize the emission and decrease the hazard level. In this paper, the activity of cerium oxide for catalytic combustion of diesel soot was studied. Thin films of cerium dioxide were synthesized by atomic layer deposition using tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionato)cerium [Ce(thd){sub 4}] and ozone as precursors. The characteristics of the films were studied as a function of deposition conditions within the reaction temperature range of 180–350 °C. Thickness, crystallinity, elemental composition, and morphology of the CeO{sub 2} films deposited on Si (100) were characterized by ellipsometry, x-ray diffraction, x-ray photoelectron spectroscopy, atomic force microscopy, and field emission scanning electron microscopy, respectively. The growth rate of CeO{sub 2} was observed to be 0.30 Å/cycle at temperatures up to 250 °C with a slight increase to 0.37 Å/cycle at 300 °C. The effect of CeO{sub 2} films grown on stainless steel foil supports on soot combustion was measured with annealing tests. Based on the analysis of these, in catalytic applications, CeO{sub 2} has been shown to be effective in lowering the soot combustion temperature from 600 °C for the uncoated substrates to 370 °C for the CeO{sub 2} coated ones. It was found that the higher deposition temperatures had a positive effect on the catalyst performance.

  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

    International Nuclear Information System (INIS)

    Cassee, Flemming R.; Campbell, Arezoo; Boere, A. John F.; McLean, Steven G.; Duffin, Rodger; Krystek, Petra; Gosens, Ilse; Miller, Mark R.

    2012-01-01

    Background: Cerium oxide (CeO 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 −/− ) mice were exposed by inhalation to diluted exhaust (1.7 mg/m 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 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 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. 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.

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

    Science.gov (United States)

    Cassee, Flemming R; Campbell, Arezoo; Boere, A John F; McLean, Steven G; Duffin, Rodger; Krystek, Petra; Gosens, Ilse; Miller, Mark R

    2012-05-01

    Cerium oxide (CeO(2)) nanoparticles improve the burning efficiency of fuel, however, little is known about health impacts of altered emissions from the vehicles. Atherosclerosis-prone apolipoprotein E knockout (ApoE(-/-)) mice were exposed by inhalation to diluted exhaust (1.7 mg/m(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. Addition of CeO(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. These results imply that addition of CeO(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. Copyright © 2012 Elsevier Inc. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    NARCIS (Netherlands)

    Cassee, Flemming R.; Campbell, Arezoo; Boere, A. John F.; McLean, Steven G.; Duffin, Rodger; Krystek, Petra; Gosens, Ilse; Miller, Mark R.

    Bacground: Cerium oxide (CeO 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 -/-) mice were exposed by inhalation to diluted exhaust (1.7mg/m

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

    Directory of Open Access Journals (Sweden)

    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.

  11. 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.

  12. Calcination of the cerium concentrate to be cerium oxide

    International Nuclear Information System (INIS)

    Suyanti; MV Purwani

    2016-01-01

    Calcination of the cerium concentrate to be cerium oxide has done. The cerium concentrate were obtained from the Ce making process wear KBrO_3 and without using KBrO_3. The calcination were done with a variation of time 1, 2, 3 and 4 hours with the temperature variations of 700, 800 and 900°C. The easiest calcination of Ce concentrates to be CeO_2 containing majority of Ce(OH)_4 and contains least impurities as Th(OH)_4, (NH_4)_2Y(NO_3), H_4N_5O_1_2La, H_1_2N_3NdO_1_5 and N_3O_9Sm. On the calcination of Ce concentrates process results without using KBrO_3 1, the calcination temperature 900°C was obtained CeO_2 content of 73.53% for calcination time of 4 hours, has little difference when compared with the predictions and calculation result of complete calcination was equal 73.84%. (author)

  13. Cerium and yttrium oxide nanoparticles are neuroprotective

    International Nuclear Information System (INIS)

    Schubert, David; Dargusch, Richard; Raitano, Joan; Chan, S.-W.

    2006-01-01

    The responses of cells exposed to nanoparticles have been studied with regard to toxicity, but very little attention has been paid to the possibility that some types of particles can protect cells from various forms of lethal stress. It is shown here that nanoparticles composed of cerium oxide or yttrium oxide protect nerve cells from oxidative stress and that the neuroprotection is independent of particle size. The ceria and yttria nanoparticles act as direct antioxidants to limit the amount of reactive oxygen species required to kill the cells. It follows that this group of nanoparticles could be used to modulate oxidative stress in biological systems

  14. Electrochemical reduction of cerium oxide into metal

    Energy Technology Data Exchange (ETDEWEB)

    Claux, Benoit [CEA, Valduc, F-21120 Is-sur-Tille (France); Universite de Grenoble, LEPMI-ENSEEG, 1130 rue de la Piscine, BP75, F-38402 St Martin d' Heres Cedex (France); Serp, Jerome, E-mail: jerome.serp@cea.f [CEA, Valduc, F-21120 Is-sur-Tille (France); Fouletier, Jacques [Universite de Grenoble, LEPMI-ENSEEG, 1130 rue de la Piscine, BP75, F-38402 St Martin d' Heres Cedex (France)

    2011-02-28

    The Fray Farthing and Chen (FFC) and Ono and Suzuki (OS) processes were developed for the reduction of titanium oxide to titanium metal by electrolysis in high temperature molten alkali chloride salts. The possible transposition to CeO{sub 2} reduction is considered in this study. Present work clarifies, by electro-analytical techniques, the reduction pathway leading to the metal. The reduction of CeO{sub 2} into metal was feasible via an indirect mechanism. Electrolyses on 10 g of CeO{sub 2} were carried out to evaluate the electrochemical process efficiency. Ca metal is electrodeposited at the cathode from CaCl{sub 2}-KCl solvent and reacts chemically with ceria to form not only metallic cerium, but also cerium oxychloride.

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

    International Nuclear Information System (INIS)

    Prabaharan, Devadoss Mangalam Durai Manoharadoss; Sadaiyandi, Karuppasamy; Mahendran, Manickam; Sagadevan, Suresh

    2016-01-01

    Cerium oxide (CeO 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)

  16. 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)

  17. Electrochemical reduction of cerium oxides in molten salts

    International Nuclear Information System (INIS)

    Claux, B.; Serp, J.; Fouletier, J.

    2011-01-01

    This brief article describes a pyrochemical process that is used by CEA to turn actinide oxides into metal actinides. This process is applied to Cerium oxides (CeO 2 ) that simulate actinide oxides well chemically as cerium belongs to the lanthanide family. The process is in fact an electrolysis of cerium oxide in a bath of molten calcium chloride salt whose temperature is between 800 and 900 Celsius degrees. At those temperatures calcium chloride becomes a ionic liquid (Ca 2+ and Cl - ) that is a good electrical conductor and is particularly well-adapted as solvent to an electrolytic process. The electrolysis current allows the transformation of solvent Ca 2+ ions into metal calcium which, in turn, can reduce cerium oxide into metal cerium through chromatically. Experimental data shows the reduction of up to 90% of 10 g samples of CeO 2 in a 6 hour long electrolysis while the best reduction rate ever known was 80% so far. This result is all the more promising that cerium oxides are more difficult to reduce than actinide oxides from the thermodynamical perspective

  18. Thin film ionic conductors based on cerium oxide

    International Nuclear Information System (INIS)

    Haridoss, P.; Hellstrom, E.; Garzon, F.H.; Brown, D.R.; Hawley, M.

    1994-01-01

    Fluorite and perovskite structure cerium oxide based ceramics are a class of materials that may exhibit good oxygen ion and/or protonic conductivity. The authors have successfully deposited thin films of these materials on a variety of substrates. Interesting orientation relationships were noticed between cerium oxide films and strontium titanate bi-crystal substrates. Near lattice site coincidence theory has been used to study these relationships

  19. 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.

  20. Chlorination and Carbochlorination of Cerium Oxide

    International Nuclear Information System (INIS)

    Esquivel, Marcelo; Bohe, Ana; Pasquevich, Daniel

    2000-01-01

    The chlorination and carbochlorination of cerium oxide were studied by thermogravimetry under controlled atmosphere (TG) in the 700 0 C 950 0 C temperature range.Both reactants and products were analyzed by X-ray diffraction (RX), scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS). Thermodynamic calculations were performed by computer assisted software.The chlorination starts at a temperature close to 800 0 C.This reaction involves the simultaneous formation and evaporation of CeCl3.Both processes control the reaction rate and their kinetic may not be easily separated.The apparent chlorination activation energy in the 850 0 C-950 0 C temperature range is 172 to 5 kJ/ mole.Carbon transforms the CeO2-Cl2 into a more reactive system: CeO2-C-Cl2, where the effects of the carbon content, total flow rate and temperature were analyzed.The carbochlorination starting temperature is 700 0 C.This reaction is completed in one step controlled by mass transfer with an apparent activation energy of 56 to 5 kJ/mole in the 850 0 C-950 0 C temperature range

  1. Preparation of cerium oxide for lens polishing powder

    International Nuclear Information System (INIS)

    Injarean, Uthaiwan; Rodthongkom, Chouvana; Pichestapong, Pipat; Changkrurng, Kalaya

    2003-10-01

    Cerium is an element of rare earth group which is called lanthanide series. It is found in the ores like monazite and xenotime which are the tailings of tin mines in the south of Thailand. Cerium is used mostly as lens polishing powder besides the applications in other industries. In this study, cerium extracted from monazite ore breakdown by alkaline process was used for the preparation of lens polishing powder. Cerium hydroxide cake from the process was dissolved by hydrochloric acid and precipitated with oxalic acid. The oxalate precipitate then was calcined to oxide powder and its particle size was measured. Precipitation conditions being studied are concentration of feed cerium chloride solution, concentration of oxalic acid used for the precipitation, concentration of sulfuric acid used as precipitation control reagent and the precipitation temperature. It was found that the appropriate precipitation conditions yielded the fine oxide powder with particle size about 12μm. The oxide powder can be ground to the size of 1-3 μm which is suitable for making lens polishing powder

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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 CeO_2 was increased. Synthesized nanoparticle were characterized by the XRD and UV absorption techniques.

  3. 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...

  4. Gas sensing behaviour of cerium oxide and magnesium aluminate

    Indian Academy of Sciences (India)

    Gas sensing behaviour of cerium oxide and magnesium aluminate composites ... A lone pairof the electron state was identified from the electro paramagnetic ... carbon monoxide (CO) (at 0.5, 1.0 and 1.5 bar) and ethanol (at 50 and 100 ppm) was ... The magnitude of the temperature varied linearly regardless of the gas ...

  5. 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.

  6. Cerium oxide and platinum nanoparticles protect cells from oxidant-mediated apoptosis

    International Nuclear Information System (INIS)

    Clark, Andrea; Zhu Aiping; Sun Kai; Petty, Howard R.

    2011-01-01

    Catalytic nanoparticles represent a potential clinical approach to replace or correct aberrant enzymatic activities in patients. Several diseases, including many blinding eye diseases, are promoted by excessive oxidant stress due to reactive oxygen species (ROS). Cerium oxide and platinum nanoparticles represent two potentially therapeutic nanoparticles that de-toxify ROS. In the present study, we directly compare these two classes of catalytic nanoparticles. Cerium oxide and platinum nanoparticles were found to be 16 ± 2.4 and 1.9 ± 0.2 nm in diameter, respectively. Using surface plasmon-enhanced microscopy, we find that these nanoparticles associate with cells. Furthermore, cerium oxide and platinum nanoparticles demonstrated superoxide dismutase catalytic activity, but did not promote hemolytic or cytolytic pathways in living cells. Importantly, both cerium oxide and platinum nanoparticles reduce oxidant-mediated apoptosis in target cells as judged by the activation of caspase 3. The ability to diminish apoptosis may contribute to maintaining healthy tissues.

  7. 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...

  8. Oxidative stress induced by cerium oxide nanoparticles in cultured BEAS-2B cells

    International Nuclear Information System (INIS)

    Park, Eun-Jung; Choi, Jinhee; Park, Young-Kwon; Park, Kwangsik

    2008-01-01

    Cerium oxide nanoparticles of different sizes (15, 25, 30, 45 nm) were prepared by the supercritical synthesis method, and cytotoxicity was evaluated using cultured human lung epithelial cells (BEAS-2B). Exposure of the cultured cells to nanoparticles (5, 10, 20, 40 μg/ml) led to cell death, ROS increase, GSH decrease, and the inductions of oxidative stress-related genes such as heme oxygenase-1, catalase, glutathione S-transferase, and thioredoxin reductase. The increased ROS by cerium oxide nanoparticles triggered the activation of cytosolic caspase-3 and chromatin condensation, which means that cerium oxide nanoparticles exert cytotoxicity by an apoptotic process. Uptake of the nanoparticles to the cultured cells was also tested. It was observed that cerium oxide nanoparticles penetrated into the cytoplasm and located in the peri-region of the nucleus as aggregated particles, which may induce the direct interaction between nanoparticles and cellular molecules to cause adverse cellular responses

  9. Fundamental aspects of regenerative cerium oxide nanoparticles and their applications in nanobiotechnology

    Science.gov (United States)

    Patil, Swanand D.

    Cerium oxide has been used extensively for various applications over the past two decades. The use of cerium oxide nanoparticles is beneficial in present applications and can open avenues for future applications. The present study utilizes the microemulsion technique to synthesize uniformly distributed cerium oxide nanoparticles. The same technique was also used to synthesize cerium oxide nanoparticles doped with trivalent elements (La and Nd). The fundamental study of cerium oxide nanoparticles identified variations in properties as a function of particle size and also due to doping with trivalent elements (La and Nd). It was found that the lattice parameter of cerium oxide nanoparticles increases with decrease in particle size. Also Raman allowed mode shift to lower energies and the peak at 464 cm-1 becomes broader and asymmetric. The size dependent changes in cerium oxide were correlated to increase in oxygen vacancy concentration in the cerium oxide lattice. The doping of cerium oxide nanoparticles with trivalent elements introduces more oxygen vacancies and expands the cerium oxide lattice further (in addition to the lattice expansion due to the size effect). The lattice expansion is greater for La-doped cerium oxide nanoparticles compared to Nd-doping due to the larger ionic radius of La compared to Nd, the lattice expansion is directly proportional to the dopant concentration. The synthesized cerium oxide nanoparticles were used to develop an electrochemical biosensor of hydrogen peroxide (H2O2). The sensor was useful to detect H2O2 concentrations as low as 1muM in water. Also the preliminary testing of the sensor on tomato stem and leaf extracts indicated that the sensor can be used in practical applications such as plant physiological studies etc. The nanomolar concentrations of cerium oxide nanoparticles were also found to be useful in decreasing ROS (reactive oxygen species) mediated cellular damages in various in vitro cell cultures. Cerium oxide

  10. Synthesis and crystal kinetics of cerium oxide nanocrystallites prepared by co-precipitation process

    International Nuclear Information System (INIS)

    Shih, C.J.; Chen, Y.J.; Hon, M.H.

    2010-01-01

    Cerium oxide nanocrystallites were synthesized at a relatively low temperature using cerium nitrate as starting materials in a water solution by a co-precipitation process. Effect of calcination temperature on the crystallite growth of cerium oxide nano-powders was investigated by X-ray diffraction, transmission electron microscopy and electron diffraction. The crystallization temperature of the cerium oxide powders was estimated to be about 273 K by XRD analysis. When calcined from 473 to 1273 K, the crystallization of the face-centered cubic phase was observed by XRD. The crystallite size of the cerium oxide increased from 10.0 to 43.8 nm with calcining temperature increasing from 673 to 1273 K. The activation energy for growth of cerium oxide nanoparticles was found to be 16.0 kJ mol -1 .

  11. Synthesis and crystal kinetics of cerium oxide nanocrystallites prepared by co-precipitation process

    Energy Technology Data Exchange (ETDEWEB)

    Shih, C.J., E-mail: cjshih@kmu.edu.tw [Department of Fragrance and Cosmetics Science, Kaohsiung Medical University, 100 Shi-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Chen, Y.J. [Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Hon, M.H. [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)

    2010-05-15

    Cerium oxide nanocrystallites were synthesized at a relatively low temperature using cerium nitrate as starting materials in a water solution by a co-precipitation process. Effect of calcination temperature on the crystallite growth of cerium oxide nano-powders was investigated by X-ray diffraction, transmission electron microscopy and electron diffraction. The crystallization temperature of the cerium oxide powders was estimated to be about 273 K by XRD analysis. When calcined from 473 to 1273 K, the crystallization of the face-centered cubic phase was observed by XRD. The crystallite size of the cerium oxide increased from 10.0 to 43.8 nm with calcining temperature increasing from 673 to 1273 K. The activation energy for growth of cerium oxide nanoparticles was found to be 16.0 kJ mol{sup -1}.

  12. Electron donating and acid-base properties of cerium oxide and its mixed oxides with alumina

    International Nuclear Information System (INIS)

    Sugunan, S.; Jalaja, J.M.

    1994-01-01

    The electron donating properties of cerium oxide activated at 300, 500 and 800 degC and of its mixed oxides with alumina were examined based on the adsorption of electron acceptors exhibiting different electron affinities. The surface acidity/basicity of the oxides was determined by titrimetry; the H 0,max values are given. The limit of electron transfer from the oxide surface lies within the region of 1.77 and 2.40 eV in terms of the electron affinity of the electron acceptor. Cerium oxide promotes the electron donor nature of alumina while leaving the limit of electron transfer unchanged. 2 tabs., 4 figs., 13 refs

  13. 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.

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

    International Nuclear Information System (INIS)

    Cho, Young Jun; Jang, Hanmin; Lee, Kwan-Soo; Kim, Dong Rip

    2015-01-01

    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

  15. Ultrasound-Assisted Oxidative Desulfurization of Diesel

    OpenAIRE

    Niran K. Ibrahim; Walla A. Noori; Jaffar M. Khasbag

    2016-01-01

    Due to the dramatic environmental impact of sulfur emissions associated with the exhaust of diesel engines, last environmental regulations for ultra-low-sulfur diesel require a very deep desulfurization (up to 15 ppm), which cannot be met by the conventional hydrodesulfurization units alone. The proposed method involves a batch ultrasound-assisted oxidative desulfurization (UAODS) of a previously hydrotreated diesel (containing 480 ppm sulfur) so as to convert the residual sulfur-bearing comp...

  16. Pilot demonstration of cerium oxide coated anodes

    Energy Technology Data Exchange (ETDEWEB)

    Gregg, J.S.; Frederick, M.S.; Shingler, M.J.; Alcorn, T.R.

    1992-10-01

    Cu cermet anodes were tested for 213 to 614 hours with an in-situ deposited CEROX coating in a pilot cell operated by Reynolds Manufacturing Technology Laboratory. At high bath ratio ([approximately]1.5) and low current density (0.5 A/cm[sup 2]), a [ge]1 mm thick dense CEROX coating was deposited on the anodes. At lower bath ratios and higher current density, the CEROX coating was thinner and less dense, but no change in corrosion rate was noted. Regions of low current density on the anodes and sides adjacent to the carbon anode sometimes had thin or absent CEROX coatings. Problems with cracking and oxidation of the cermet substrates led to higher corrosion rates in a pilot cell than would be anticipated from lab scale results.

  17. Thermally stimulated iron oxide transformations and magnetic behaviour of cerium dioxide/iron oxide reactive sorbents

    Czech Academy of Sciences Publication Activity Database

    Luňáček, J.; Životský, O.; Jirásková, Yvonna; Buršík, Jiří; Janoš, P.

    2016-01-01

    Roč. 120, OCT (2016), s. 295-303 ISSN 1044-5803 R&D Projects: GA MŠk(CZ) LQ1601 Institutional support: RVO:68081723 Keywords : Oxide -nano-composites * Mössbauer spectroscopy * TEM * Cerium oxide * Magnetic parameters Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.714, year: 2016

  18. 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.

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

    International Nuclear Information System (INIS)

    Ševčíková, Klára; Nehasil, Václav; Vorokhta, Mykhailo; Haviar, Stanislav; Matolín, Vladimír

    2015-01-01

    Highlights: • Thin films of ceria doped by rhodium deposited by RF magnetron sputtering. • Concentration of rhodium has great impact on properties of Rh–CeO 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 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 4+ and Ce 3+ and rhodium occurs in two oxidation states, Rh 3+ and Rh n+ . We show that the concentration of rhodium has a great influence on the chemical composition, structure and reducibility of the Rh–CeO 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 x thin films leads to preparing materials with different properties

  20. Structure and activity of tellurium-cerium oxide acrylonitrile catalysts

    International Nuclear Information System (INIS)

    Bart, J.C.J.; Giordano, N.

    1982-01-01

    Ammoxidation of propylene to acrylonitrile (ACN) was investigated over various silica-supported (Te,Ce)O catalysts at 360 and 440 0 C. The binary oxide system used consists of a single nonstoichiometric fluorite-type phase α-(Ce,Te)O 2 up to about 80 mole% TeO 2 and a tellurium-saturated solid solution β-(Ce,Te)O 2 at higher tellurium concentrations. The ACN yield varies almost linearly with the tellurium content of (Ce,Te)O 2 . The β-(Ce,Te)O 2 phase is the most active component of the system (propylene conversion and ACN selectivity at 440 C of 76.7 and 74%, respectively) and is slightly more selective to ACN than α-Te0 2 . Tellurium reduces the overoxidation properties of cerium and selective oxidation occurs through Te(IV)-bonded oxygen

  1. Cerium fluoride nanoparticles protect cells against oxidative stress

    International Nuclear Information System (INIS)

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

    2015-01-01

    A novel facile method of non-doped and fluorescent terbium-doped cerium fluoride stable aqueous sols synthesis is proposed. Intense green luminescence of CeF 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 3 nanoparticles are shown to provide noteworthy protection to cells against the vesicular stomatitis virus. - Highlights: • Facile method of CeF 3 and CeF 3 :Tb stable aqueous sols synthesis is proposed. • Naked CeF 3 nanoparticles are shown to be non-toxic and to protect cells from the action of H 2 O 2 . • CeF 3 and CeF 3 :Tb nanoparticles are shown to protect living cells against the vesicular stomatitis virus

  2. 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.

  3. Desulfurization of oxidized diesel using ionic liquids

    Science.gov (United States)

    Wilfred, Cecilia D.; Salleh, M. Zulhaziman M.; Mutalib, M. I. Abdul

    2014-10-01

    The extraction of oxidized sulfur compounds from diesel were carried out using ten types of ionic liquids consisting of different cation and anion i.e. 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazoium thiocyanate, 1-butyl-3-methylimidazoium dicyanamide, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazoliumhexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, trioctylmethylammonium chloride, 1-propionitrile-3-butylimidazolium thiocyanate, 1-propionitrile-3-butylimidazolium dicyanamide and 1-butyl-6-methylquinolinium dicyanamide. The oxidation of diesel was successfully done using phosphotungstic acid as the catalyst, hydrogen peroxide (H2O2) as the oxidant and trioctylmethylammonium chloride as the phase transfer agent. The oxidation of diesel changes the sulfur compounds into sulfone which increases its polarity and enhances the ionic liquid's extraction performance. Result showed that ionic liquid [C4mquin][N(CN)2] performed the highest sulfur removal (91% at 1:5 diesel:IL ratio) compared to the others.

  4. 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.

  5. Nanoporous cerium oxide thin film for glucose biosensor.

    Science.gov (United States)

    Saha, Shibu; Arya, Sunil K; Singh, S P; Sreenivas, K; Malhotra, B D; Gupta, Vinay

    2009-03-15

    Nanoporous cerium oxide (CeO(2)) thin film deposited onto platinum (Pt) coated glass plate using pulsed laser deposition (PLD) has been utilized for immobilization of glucose oxidase (GOx). Atomic force microscopy studies reveal the formation of nanoporous surface morphology of CeO(2) thin film. Response studies carried out using differential pulsed voltammetry (DPV) and optical measurements show that the GOx/CeO(2)/Pt bio-electrode shows linearity in the range of 25-300 mg/dl of glucose concentration. The low value of Michaelis-Menten constant (1.01 mM) indicates enhanced enzyme affinity of GOx to glucose. The observed results show promising application of the nanoporous CeO(2) thin film for glucose sensing application without any surface functionalization or mediator.

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

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; Fransen, T.; Geerdink, Bert; 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

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

    Czech Academy of Sciences Publication Activity Database

    Janos, P.; Henych, Jiří; Pelant, O.; Pilařová, V.; Vrtoch, L.; Kormunda, M.; Mazanec, K.; Štengl, Václav

    2016-01-01

    Roč. 304, MAR (2016), s. 259-268 ISSN 0304-3894 Institutional support: RVO:61388980 Keywords : Cerium oxide * Chemical warfare agents * Organophosphate compounds * Decontamination Subject RIV: CA - Inorganic Chemistry Impact factor: 6.065, year: 2016

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

    Science.gov (United States)

    Cho, Young Jun; Jang, Hanmin; Lee, Kwan-Soo; Kim, Dong Rip

    2015-06-01

    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.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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_2, CA + nCeO_2) bulk cerium oxide (bCeO_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_2 increased shoot length by ~ 9 and ~ 13%, respectively, while bCeO_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_2 at 250 mg/kg, but reduced by bCeO_2 at 62.5 mg/kg, compared with MPW. At 250 and 500 mg/kg, nCeO_2 increased Ce in roots by 10 and 7 times, compared to CA + nCeO_2, but none of the treatments affected the Ce concentration in above ground tissues. Neither nCeO_2 nor CA + nCeO_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_2 at 62.5 increased Zn (152%) but reduced P (80%) in stems. Only nCeO_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_2 on tomato plants. - Highlights: • At 500 mg/kg, coated and bare NPs increased stem length by 13 and 9%, respectively. • Coated NPs at 500 mg/kg increased CAT activity in

  10. Imidazolium ionic liquids as solvents for cerium(IV)-mediated oxidation reactions

    OpenAIRE

    Mehdi, Hasan; Bodor, Andrea; Lantos, Diana; Horváth, István T; De Vos, Dirk; Binnemans, Koen

    2007-01-01

    Use of imidazolium ionic liquids as solvents for organic transformations with tetravalent cerium salts as oxidizing agents was evaluated. Good solubility was found for ammonium hexanitratocerate(IV) (ceric ammonium nitrate, CAN) and cerium(IV) triflate in 1-alkyl-3-methylimidazolium triflate ionic liquids. Oxidation of benzyl alcohol to benzaldehyde in 1-ethyl-3-methylimidazolium triflate was studied by in-situ FTIR spectroscopy and 13C NMR spectroscopy on carbon-13-labeled benzyl alcohol. Ca...

  11. 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...

  12. Synthesis, characterization and antibacterial activity of hybrid chitosan-cerium oxide nanoparticles: As a bionanomaterials.

    Science.gov (United States)

    Senthilkumar, R P; Bhuvaneshwari, V; Ranjithkumar, R; Sathiyavimal, S; Malayaman, V; Chandarshekar, B

    2017-11-01

    The hybrid chitosan cerium oxide nanoparticles were prepared for the first time by green chemistry approach using plant leaf extract. The intense peak observed around 292nm in the UV-vis spectrum indicate the formation of cerium oxide nanoparticles. The XRD pattern revealed that the hybrid chitosan-cerium oxide nanoparticles have a polycrystalline structure with cubic fluorite phase. The FTIR spectrum of prepared samples showed the formation of Ce-O bonds and chitosan main chains COC and CO. The FESEM image of hybrid chitosan cerium oxide nanoparticles revealed that the particles are spherical in shape with grains size varying from 23.12nm to 89.91nm. EDAX analysis confirmed the presence of Ce, O, C and N elements in the prepared sample. TEM images showed that the prepared hybrid chitosan-cerium oxide nanoparticles are predominantly uniform in size and most of the particles are spherical in shape with less agglomeration and the particles size varies from 3.61nm to 24.40nm. The prepared chitosan cerium oxide nanoparticles of 50μL concentration showed good antibacterial properties against test pathogens, which was confirmed by the FESEM analysis. The prepared small particle size facilitate that these hybrid ChiCO 2 NPs could effectively be used in biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. 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.

  14. Diesel soot oxidation under controlled conditions

    OpenAIRE

    Song, Haiwen

    2003-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University, 11/12/2003. In order to improve understanding of diesel soot oxidation, an experimental rig was designed and set up, in which the soot oxidation conditions, such as temperature, oxygen partial pressure, and CO2 partial pressure, could be varied independently of each other. The oxidizing gas flow in the oxidizer was under laminar condition. This test rig comprised a naturally-aspirated single ...

  15. 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)

  16. Optical properties of cerium oxide (CeO2) nanoparticles synthesized by hydroxide mediated method

    Science.gov (United States)

    Ali, Mawlood Maajal; Mahdi, Hadeel Salih; Parveen, Azra; Azam, Ameer

    2018-05-01

    The nanoparticles of cerium oxide have been successfully synthesized by hydroxide mediated method, using cerium nitrate and sodium hydroxide as precursors. The microstructural properties were analyzed by X-ray diffraction technique (XRD). The X-ray diffraction results show that the cerium oxide nanoparticles were in cubic structure. The optical absorption spectra of cerium oxide were recorded by UV-VIS spectrophotometer in the range of 320 to 600 nm and photoluminescence spectra in the range of 400-540 nm and have been presented. The energy band gap was determined by Tauc relationship. The crystallite size was determined from Debye-Scherer equation and came out to be 6.4 nm.

  17. The acute pulmonary and thrombotic effects of cerium oxide nanoparticles after intratracheal instillation in mice

    Directory of Open Access Journals (Sweden)

    Nemmar A

    2017-04-01

    Full Text Available Abderrahim Nemmar,1 Suhail Al-Salam,2 Sumaya Beegam,1 Priya Yuvaraju,2 Badreldin H Ali3 1Department of Physiology, 2Department of Pathology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, UAE; 3Department of Pharmacology and Clinical Pharmacy, College of Medicine & Health Sciences, Sultan Qaboos University, Muscat, Al-Khod, Sultanate of Oman Abstract: Cerium oxide nanoparticles (CeO2 NPs, used as a diesel fuel catalyst, can be emitted into the ambient air, resulting in exposure to humans by inhalation. Recent studies have reported the development of lung toxicity after pulmonary exposure to CeO2 NPs. However, little is known about the possible thrombotic effects of these NPs. The present study investigated the acute (24 hours effect of intratracheal (IT instillation of either CeO2 NPs (0.1 or 0.5 mg/kg or saline (control on pulmonary and systemic inflammation and oxidative stress and thrombosis in mice. CeO2 NPs induced a significant increase of neutrophils into the bronchoalveolar lavage (BAL fluid with an elevation of tumor necrosis factor α (TNFα and a decrease in the activity of the antioxidant catalase. Lung sections of mice exposed to CeO2 NPs showed a dose-dependent infiltration of inflammatory cells consisting of macrophages and neutrophils. Similarly, the plasma levels of C-reactive protein and TNFα were significantly increased, whereas the activities of catalase and total antioxidant were significantly decreased. Interestingly, CeO2 NPs significantly and dose dependently induced a shortening of the thrombotic occlusion time in pial arterioles and venules. Moreover, the plasma concentrations of fibrinogen and plasminogen activator inhibitor-1 were significantly elevated by CeO2 NPs. The direct addition of CeO2 NPs (1, 5, or 25 µg/mL to mouse whole blood, collected from the inferior vena cava, in vitro neither caused significant platelet aggregation nor affected prothrombin time or partial

  18. Ultrasound-Assisted Oxidative Desulfurization of Diesel

    Directory of Open Access Journals (Sweden)

    Niran K. Ibrahim

    2016-11-01

    Full Text Available Due to the dramatic environmental impact of sulfur emissions associated with the exhaust of diesel engines, last environmental regulations for ultra-low-sulfur diesel require a very deep desulfurization (up to 15 ppm, which cannot be met by the conventional hydrodesulfurization units alone. The proposed method involves a batch ultrasound-assisted oxidative desulfurization (UAODS of a previously hydrotreated diesel (containing 480 ppm sulfur so as to convert the residual sulfur-bearing compounds into their corresponding highly polar oxides, which can be eliminated easily by extraction with a certain highly polar solvent. The oxidizing system utilized was H2O2 as an oxidant, CH3COOH as a promoter, with FeSO4 as a catalyst; whereas acetonitrile was used as extractant. The major influential parameters related to UAODS process have been investigated, namely: ratio of oxidant/fuel, ratio of the promoter/oxidant, dose of catalyst, reaction temperature, and intensity of ultrasonic waves. Kinetics of the reaction has been also studied; it was observed that the UAODS of diesel fuels fitted pseudo-first-order kinetics under the best experimental conditions, whereas values of the apparent rate constant and activation energy were 0.373 min-1 and 24 KJ/mol, respectively. The oxidation treatment, in combination with ultrasonic irradiation, revealed a synergistic effect for diesel desulfurization. The experimental results showed that sulfur removal efficiency could amount to 98% at mild operating conditions (70 ○C and 1 bar. This indicates that the process is efficient and promising for the production of ultra-low-sulfur diesel fuels.

  19. 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.

  20. 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

    This work evaluates the performance of cobalt/cerium oxide (Co/CeO2) composite coatings and pure Co coatings to be used for solid oxide fuel cell (SOFC) interconnects. The coatings are electroplated on the ferritic stainless steels Crofer 22 APU and Crofer 22H. Coated and uncoated samples...

  1. Determination of trace amounts of cerium in silicate rocks based on its candoluminescence in a calcium oxide based matrix

    International Nuclear Information System (INIS)

    Belcher, R.; Nasser, T.A.K.; Polo-Diez, L.; Townshend, A.

    1977-01-01

    A very sensitive method for the determination of cerium (above 10 ng ml -1 ) has been developed (Belcher et al., Analyst;100:415(1975)), based on the measurement of the green candoluminescence produced by cerium in a calcium oxide-calcium sulphate matrix, with sulphuric acid as a coactivator, when the matrix is inserted into a hydrogen-nitrogen-air flame. This paper describes the application of this method to the determination of trace amounts of cerium in rocks. It involves the fusion of the sample with lithium metaborate, and does not require the isolation of cerium from other components of the rock, before measuring the candoluminescence intensity of the cerium. (author)

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

    International Nuclear Information System (INIS)

    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 (CeO 2 ) nanoparticles have been detected in the exhaust, which raises a health concern. Previous studies have shown that exposure of rats to nanoscale CeO 2 by intratracheal instillation (IT) induces sustained pulmonary inflammation and fibrosis. In the present study, male Sprague–Dawley rats were exposed to CeO 2 or CeO 2 coated with a nano layer of amorphous SiO 2 (aSiO 2 /CeO 2 ) by a single IT and sacrificed at various times post-exposure to assess potential protective effects of the aSiO 2 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), CeO 2 but not aSiO 2 /CeO 2 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 CeO 2 (high dose at 3.5 mg/kg) treatment at 28 days post-exposure. aSiO 2 coating significantly reduced CeO 2 -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 aSiO 2 /CeO 2 -exposed lungs up to 3 days after exposure, suggesting that aSiO 2 dissolved off the CeO 2 core, and some of the CeO 2 was transformed to CePO 4 with time. These results demonstrate that aSiO 2 coating reduce CeO 2 -induced inflammation, phospholipidosis and fibrosis. - Highlights: • Both CeO 2 and aSiO 2 /CeO 2 particles were detected in the respective particle-exposed lungs. • The

  3. Characterization of microstructure and catalytic of cerium oxide obtained by colloidal solution

    International Nuclear Information System (INIS)

    Senisse, C.A.L.; Bergmann, C.P.; Alves, A.K.

    2012-01-01

    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)

  4. 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...

  5. 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.

  6. Catalytic properties and biomedical applications of cerium oxide nanoparticles

    KAUST Repository

    Walkey, Carl D.; Das, Soumen C.; Seal, Sudipta; Erlichman, Joseph S.; Heckman, Karin L.; Ghibelli, Lina; Traversa, Enrico; McGinnis, James F.; Self, William Thomas

    2014-01-01

    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?

  7. 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?

  8. 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

  9. Nutritional quality assessment of tomato fruits after exposure to uncoated and citric acid coated cerium oxide nanoparticles, bulk cerium oxide, cerium acetate and citric acid.

    Science.gov (United States)

    Barrios, Ana Cecilia; Medina-Velo, Illya A; Zuverza-Mena, Nubia; Dominguez, Osvaldo E; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L

    2017-01-01

    Little is known about the effects of surface modification on the interaction of nanoparticles (NPs) with plants. Tomato (Solanum lycopersicum L.) plants were cultivated in potting soil amended with bare and citric acid coated nanoceria (nCeO 2, nCeO 2 +CA), cerium acetate (CeAc), bulk cerium oxide (bCeO 2 ) and citric acid (CA) at 0-500 mg kg -1 . Fruits were collected year-round until the harvesting time (210 days). Results showed that nCeO 2 +CA at 62.5, 250 and 500 mg kg -1 reduced dry weight by 54, 57, and 64% and total sugar by 84, 78, and 81%. At 62.5, 125, and 500 mg kg -1 nCeO 2 +CA decreased reducing sugar by 63, 75, and 52%, respectively and at 125 mg kg -1 reduced starch by 78%, compared to control. The bCeO 2 at 250 and 500 mg kg -1 , increased reducing sugar by 67 and 58%. In addition, when compared to controls, nCeO 2 at 500 mg kg -1 reduced B (28%), Fe (78%), Mn (33%), and Ca (59%). At 125 mg kg -1 decreased Al by 24%; while nCeO 2 +CA at 125 and 500 mg kg -1 increased B by 33%. On the other hand, bCeO 2 at 62.5 mg kg -1 increased Ca (267%), but at 250 mg kg -1 reduced Cu (52%), Mn (33%), and Mg (58%). Fruit macromolecules were mainly affected by nCeO 2 +CA, while nutritional elements by nCeO 2 ; however, all Ce treatments altered, in some way, the nutritional quality of tomato fruit. To our knowledge, this is the first study comparing effects of uncoated and coated nanoceria on tomato fruit quality. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  10. Optical properties and electronic transitions of zinc oxide, ferric oxide, cerium oxide, and samarium oxide in the ultraviolet and extreme ultraviolet

    DEFF Research Database (Denmark)

    Pauly, N; Yubero, F; Espinós, J P

    2017-01-01

    Optical properties and electronic transitions of four oxides, namely zinc oxide, ferric oxide, cerium oxide, and samarium oxide, are determined in the ultraviolet and extreme ultraviolet by reflection electron energy loss spectroscopy using primary electron energies in the range 0.3-2.0 ke...

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Thermodynamic Studies of the Phase Relationships of Nonstoichiometric Cerium Oxides at Higher Temperatures

    DEFF Research Database (Denmark)

    Sørensen, Ole Toft

    1976-01-01

    Partial molar thermodynamic quantities for oxygen in nonstoichiometric cerium oxides were determined by thermogravimetric analysis in CO/CO2 mixtures in the temperature range 900–1400°C. Under these conditions compositions within the range 2.00 greater-or-equal, slanted O/M greater-or-equal, slan......Partial molar thermodynamic quantities for oxygen in nonstoichiometric cerium oxides were determined by thermogravimetric analysis in CO/CO2 mixtures in the temperature range 900–1400°C. Under these conditions compositions within the range 2.00 greater-or-equal, slanted O/M greater...

  16. 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)

  17. Synthesis of cerium oxide catalysts supported on MCM-41 molecular sieve

    International Nuclear Information System (INIS)

    Souza, E.L.S.; Barros, T.R.B.; Sousa, B.V. de

    2016-01-01

    Porous materials have been widely studied as catalysts and catalyst support. The MCM-41 structure is the one that has been most studied because of its application possibilities in chemical processes. This work aimed to obtain and characterize cerium oxide catalysts supported on MCM-41 molecular sieve. The molecular sieve was synthesized by the conventional method with the following molar composition: 1 SiO2: 0.30 CTABr: NH3 11: 144 H2O. Then, 25% w/w cerium was incorporated into the MCM-41 using the wet impregnation process and the material obtained was activated by calcination. From the XRD patterns was confirmed the structure of the molecular sieve, and were identified the cerium oxide phases in its structure. The textural catalysts characteristics were investigated by isotherms of N2 adsorption/desorption (BET method). (author)

  18. 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.

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

    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), El Paso, TX (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), El Paso, TX (United States); Trujillo-Reyes, Jesica [Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); Sun, Youping [Texas AgriLife Research Center at El Paso, Texas A& M University System, 1380 A & M Circle, El Paso, TX 79927 (United States); Barrios, Ana C. [Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); Niu, Genhua [Texas AgriLife Research Center at El Paso, Texas A& M University System, 1380 A & M Circle, El Paso, TX 79927 (United States); Margez, Juan P. Flores- [Autonomous University of Ciudad Juarez, Departamento de Química y Biología, Instituto de Ciencias Biomédicas, Anillo envolvente PRONAF y Estocolmo, Ciudad Juarez, Chihuahua 32310, México (Mexico); 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), El Paso, TX (United States)

    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 0–500 mg/kg cerium oxide nanoparticles (nano-CeO{sub 2}) under greenhouse condition. After 52 days 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-CeO{sub 2} 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-CeO{sub 2} concentration in LOMS, the effect on the physiological processes were inconsequential. In OMES leaves, exposure to 62.5–250 mg/kg nano-CeO{sub 2} 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 250 mg/kg nano-CeO{sub 2}. In addition, catalase activity increased in LOMS stems, and ascorbate peroxidase increased in OMES leaves of nano-CeO{sub 2} 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. - Highlights: • Ce translocation to leaves was facilitated by higher organic matter (OM) in soil. • Lower soil OM increased leaf cover area in nano-CeO{sub 2} exposed plants. • Nano-CeO{sub 2} effects on metabolic processes were more

  20. Colloidal stabilization of cerium-gadolinium oxide (CGO) suspensions via rheology

    DEFF Research Database (Denmark)

    Marani, Debora; Sudireddy, Bhaskar Reddy; Bentzen, Janet Jonna

    2015-01-01

    colloidally stable state. The method was applied to explore the ability of four commercial dispersants (acidic affine, neutral, basic affine, and polyvinylpyrrolidone (PVP)) to disperse cerium-gadolinium oxide (CGO) in ethanol. Only the acidic affine and the PVP dispersants were found to efficiently disperse...

  1. Influences of the main anodic electroplating parameters on cerium oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yang; Yang, Yumeng; Du, Xiaoqing; Chen, Yu [Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang (China); Zhang, Zhao, E-mail: eaglezzy@zjuem.zju.edu.cn [Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang (China); Zhang, Jianqing [Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang (China); State Key Laboratory for Corrosion and Protection of Metals, Shenyang 110016 (China)

    2014-06-01

    Cerium oxide thin films were fabricated onto 316 L stainless steel via a potentiostatically anodic electrodeposition approach in the solutions containing cerium(III) nitrate (0.05 M), ammonia acetate (0.1 M) and ethanol (10% V/V). The electrochemical behaviors and deposition parameters (applied potential, bath temperature, dissolving O{sub 2} and bath pH) have been investigated. Results show that, the electrochemical oxidation of Ce{sup 3+} goes through one electrochemical step, which is under charge transfer control. The optimum applied potential for film deposition is 0.8 V. Bath temperature plays a significant effect on the deposition rate, composition (different colors of the film) and surface morphology of the deposits. Due to the hydrolysis of Ce{sup 3+}, cerous hydroxide is facility to form when the bath temperature is higher than 60 °C. The electroplating bath pH is another key role for the anodic deposition of cerium oxide thin films, and the best bath pH is around 6.20. N{sub 2} or O{sub 2} purged into the bath will result in film porosities and O{sub 2} favors cerium oxide particles and film generation.

  2. 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,...

  3. 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.

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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.

  5. Thermometric titrimetry Studies of the cerium(IV) oxidation of alpha-mercaptocarboxylic acids.

    Science.gov (United States)

    Alexander, W A; Mash, C J; McAuley, A

    1969-04-01

    The cerium(IV) oxidation of thioglycollic, thiolactic and thiomalic acids has been examined by thermometric titration. The titration curves indicate stoichiometries of more than 1 mole of cerium(IV) per mole of alpha-thiol, suggesting possible side-reactions. In the presence of methyl acrylate, however, the expected ratio is observed. The overall heat of each reaction has been derived. Only with a titration method of this kind where allowance can be made for side-reactions can the heats of reaction for these systems be measured.

  6. Electro-catalytic oxidation of reactive Orange 107 using cerium doped oxides of Nd3+ nanoparticle

    International Nuclear Information System (INIS)

    Rajkumar, K.; Muthukumar, M.; Mangalaraja, R.V.

    2011-01-01

    A new rare earth doped cerium oxide powder was used as a catalyst to investigate the removal of colour and TOC from simulated wastewater of Reactive Orange 107. The electro oxidation process was carried out in the reactor in presence of an electrolyte NaCl. Graphite electrode was used as anode and cathode and electrolysis were carried out at a current density of 34.96 mAcm -2 with a catalyst concentration of 0.05g L -1 . In order to find the efficiency of nanocatalyst, experiments were also conducted without catalyst. From the experiment, it was found that complete colour removal was achieved on electrocatalytic oxidation as well as electro oxidation. When comparing the above processes, catalytic oxidation shows more efficient than electro oxidation. With respect to the degradation of the dye, catalytic oxidation shows more TOC removal than the oxidation taken place without catalyst. It infers that even though the electro-catalytic oxidation process achieves complete decolouration but it does not achieve complete mineralisation. The FTIR and GCMS studies confirmed the formation of by-products. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jane, E-mail: jym1@cdc.gov [Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV (United States); Mercer, Robert R.; Barger, Mark; Schwegler-Berry, Diane [Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV (United States); Cohen, Joel M.; Demokritou, Philip [Harvard TH Chan School of Public Health, Harvard University, Boston, MA (United States); Castranova, Vincent [School of Pharmacy, West Virginia University, Morgantown, WV (United States)

    2015-10-01

    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 (CeO{sub 2}) nanoparticles have been detected in the exhaust, which raises a health concern. Previous studies have shown that exposure of rats to nanoscale CeO{sub 2} by intratracheal instillation (IT) induces sustained pulmonary inflammation and fibrosis. In the present study, male Sprague–Dawley rats were exposed to CeO{sub 2} or CeO{sub 2} coated with a nano layer of amorphous SiO{sub 2} (aSiO{sub 2}/CeO{sub 2}) by a single IT and sacrificed at various times post-exposure to assess potential protective effects of the aSiO{sub 2} 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), CeO{sub 2} but not aSiO{sub 2}/CeO{sub 2} 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 CeO{sub 2} (high dose at 3.5 mg/kg) treatment at 28 days post-exposure. aSiO{sub 2} coating significantly reduced CeO{sub 2}-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 aSiO{sub 2}/CeO{sub 2}-exposed lungs up to 3 days after exposure, suggesting that aSiO{sub 2} dissolved off the CeO{sub 2} core, and some of the CeO{sub 2} was transformed to CePO{sub 4} with time. These results demonstrate that aSiO{sub 2} coating reduce CeO{sub 2}-induced inflammation, phospholipidosis and fibrosis. - Highlights: • Both

  8. Corrosion behaviour of nanometre sized cerium oxide and titanium oxide incorporated aluminium in NaCl solution

    International Nuclear Information System (INIS)

    Ashraf, P. Muhamed; Edwin, Leela

    2013-01-01

    Highlights: ► Corrosion resistant aluminium incorporated with nano oxides of cerium and titanium. ► 0.2% nano CeO 2 and 0.05% nano TiO 2 showed increased corrosion resistance. ► Nano TiO 2 concentration influenced the optimum performance of the material. ► Comparison of Micro and nano CeO 2 and TiO 2 aluminium showed the latter is best. - Abstract: The study highlights the development of an aluminium matrix composite by incorporating mixture of nanometre sized cerium oxide and titanium oxide in pure aluminium and its corrosion resistance in marine environment. The mixed nanometre sized oxides incorporated aluminium exhibited improved microstructure and excellent corrosion resistance. Corrosion resistance depends on the concentration of nanometre sized titanium oxide. Electrochemical characteristics improved several folds in nanometre sized mixed oxides incorporated aluminium than micrometre sized oxides incorporated aluminium.

  9. 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...

  10. 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.

  11. Catalytic activity of oxide cerium-molybdenum-tellurium catalysts in oxidation ammonolysis

    International Nuclear Information System (INIS)

    Dzhordano, N.; Bart, D.; Madzhori, R.

    1984-01-01

    A commercial catalyst containing a mixture of Ce-, Mo-, Te oxides deposited on SiO 2 is shown to manifest a high efficiency in oxidative ammonolysis of propylene (C 3 - ) to acrylonitrile (AN). The dependence of the catalytic properties on the catalyst composition and reaction conditions is studied. It is established that three-component mixtures are more active and selective than the systems with a lesser number of components. Using the catalyst with the optimum ratio of constituent oxides in a microreactor at 440 deg enabled one to achieve initial selectivity in terms of AN equal to 82.5% at 97% conversion of C 3 - . Acrolein, acetonitrile, HCN and nitrogen oxides are the reaction by-products. A supposition is made that the reaction proceeds via the formation of π-compleXes on the centres of Te(4). Setective oxidation occurs on oxygen atoms bonded with the Mo(6) ions. Tellurium enhances the molybdenum reducibleness due to delocalization of electrons, whereas the cerium addition to the mixture of tellurium- and molybdenum oxides increases the rate of molybdenum reoxidation and thus enhances the catalytic system stability

  12. 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.

  13. Methods study of homogeneity and stability test from cerium oxide CRM candidate

    International Nuclear Information System (INIS)

    Samin; Susanna TS

    2016-01-01

    The methods study of homogeneity and stability test from cerium oxide CRM candidate has been studied based on ISO 13258 and KAN DP. 01. 34. The purpose of this study was to select the test method homogeneity and stability tough on making CRM cerium oxide. Prepared 10 sub samples of cerium oxide randomly selected types of analytes which represent two compounds, namely CeO_2 and La_2O_3. At 10 sub sample is analyzed CeO_2 and La_2O_3 contents in duplicate with the same analytical methods, by the same analyst, and in the same laboratory. Data analysis results calculated statistically based on ISO 13528 and KAN DP.01.34. According to ISO 13528 Cerium Oxide samples said to be homogeneous if Ss ≤ 0.3 σ and is stable if | Xr – Yr | ≤ 0.3 σ. In this study, the data of homogeneity test obtained CeO_2 is Ss = 2.073 x 10-4 smaller than 0.3 σ (0.5476) and the stability test obtained | Xr - Yr | = 0.225 and the price is < 0.3 σ. Whereas for La_2O_3, the price for homogeneity test obtained Ss = 1.649 x 10-4 smaller than 0.3 σ (0.4865) and test the stability of the price obtained | Xr - Yr | = 0.2185 where the price is < 0.3 σ. Compared with the method from KAN, a sample of cerium oxide has also been homogenized for Fcalc < Ftable and stable, because | Xi - Xhm | < 0.3 x n IQR. Provided that the results of the evaluation homogeneity and stability test from CeO_2 CRM candidate test data were processed using statistical methods ISO 13528 is not significantly different with statistical methods from KAN DP.01.34, which together meet the requirements of a homogeneous and stable. So the test method homogeneity and stability test based on ISO 13528 can be used to make CRM cerium oxide. (author)

  14. Thermally stimulated iron oxide transformations and magnetic behaviour of cerium dioxide/iron oxide reactive sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Luňáček, J., E-mail: jiri.lunacek@vsb.cz [Department of Physics, VŠB – Technical University of Ostrava, 17, listopadu 15/2172, 708 33 Ostrava-Poruba (Czech Republic); Department 606, VŠB – Technical University of Ostrava, 17, listopadu 15/2172, 708 33 Ostrava-Poruba (Czech Republic); Životský, O. [Department of Physics, VŠB – Technical University of Ostrava, 17, listopadu 15/2172, 708 33 Ostrava-Poruba (Czech Republic); Department 606, VŠB – Technical University of Ostrava, 17, listopadu 15/2172, 708 33 Ostrava-Poruba (Czech Republic); Jirásková, Y. [CEITEC IPM, Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, 616 62 Brno (Czech Republic); Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, 616 62 Brno (Czech Republic); Buršík, J. [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, 616 62 Brno (Czech Republic); Janoš, P. [Faculty of the Environment, University of Jan Evangelista Purkyně, Králova Výšina 7, 400 96 Ústí nad Labem (Czech Republic)

    2016-10-15

    The present paper is devoted to detailed study of the magnetically separable sorbents based on a cerium dioxide/iron oxide composite annealed at temperatures T{sub a} = 773 K, 873 K, and 973 K. The X-ray diffraction and high resolution transmission electron microscopy are used to determine the phase composition and microstructure morphology. Mössbauer spectroscopy at room (300 K) and low (5 K) temperatures has contributed to more exact identification of iron oxides and their transformations Fe{sub 3}O{sub 4} → γ-Fe{sub 2}O{sub 3} (ε-Fe{sub 2}O{sub 3}) → α-Fe{sub 2}O{sub 3} in dependence on calcination temperature. Different iron oxide phase compositions and grain size distributions influence the magnetic characteristics determined from the room- and low-temperature hysteresis loop measurements. The results are supported by zero-field-cooled and field-cooled magnetization measurements allowing a quantitative estimation of the grain size distribution and its effect on the iron oxide transformations. - Highlights: •Magnetically separable sorbents based on a CeO{sub 2}/Fe{sub 2}O{sub 3} composite were investigated. •Microstructure of sorbents was determined by XRD, TEM and Mössbauer spectroscopy. •Magnetic properties were studied by hysteresis loops at room- and low-temperatures. •Phase transitions of iron oxides with increasing annealing temperature are observed.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Joshua K.; Arcibar-Orozco, Javier A.; Bandosz, Teresa J., E-mail: tbandosz@ccny.cuny.edu

    2016-12-30

    Highlights: • Microporous zirconium-cerium (hydr) oxides were synthetized. • Ce presence narrowed the band gap of the materials. • The samples showed a high efficiency for removal of CEES vapors. • 1,2-Bis (ethyl thio) ethane and ethyl vinyl sulfide were the main reaction products. • 5% (Ce/Zr mol) addition of cerium oxide results in the best performing material. - Abstract: Highly porous cerium oxide modified Zr(OH){sub 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 (CeO{sub 2}) and hydroxide (Zr(OH){sub 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.

  16. Characterization of composite metal-ceramic of nickel-oxide cerium doped gadolinium

    International Nuclear Information System (INIS)

    Silva, M.L.A. da; Varela, M.C.R.S.

    2016-01-01

    Composite nickel doped cerium oxide are used in SOFC anode materials. In this study we evaluated the effect of the presence of gadolinium on the properties of composite nickel and ceria and. The supports were synthesized by sol-gel method. The impregnation with nickel nitrate was taken sequentially, followed by calcination. The materials were characterized by X-ray diffraction, measurement of specific surface area, temperature programmed reduction, Raman spectroscopy. The presence of gadolinium retained the fluorite structure of ceria by forming a solid solution, also not influencing significantly on the specific surface area of the support. On the other hand, there was a decrease in the area catalysts, which can be attributed to sintering of nickel. Furthermore, addition of gadolinium favored the formation of intrinsic and extrinsic vacancies in cerium oxide, which leads to an increase in the ionic conductivity of the solid, desirable property for an SOFC anode catalyst. (author)

  17. 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)

  18. 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.

  19. Zirconia dispersion as a toughening agent in alumina - Influence of the cerium oxide

    International Nuclear Information System (INIS)

    Gritti, Olivier

    1987-01-01

    The improvement of mechanical properties of alumina can be obtained by fine dispersion of zirconia particles. The addition of cerium oxide as a stabilizer of the tetragonal phase has been examined. Different powder preparations, based on impregnation of the alumina powder by zirconium and cerium precursor salts, have been studied. Parameters, such as properties of alumina powder and cerium oxide content, for the production of reactive powders have been determined by two laboratory processes. The sintering of these powders in air at 1600 deg. C has resulted in dense materials with homogeneous microstructure. The mechanical properties, in particular the biaxial flexure strength and the toughness, have been determined in the temperature range 20 deg. C-900 deg. C. A reinforcement of about 80 pc in comparison with alumina is achieved. The optimal composition is (Al 2 O 3 ) 0.8 (ZrO 2 ) 0.18 (CeO 2 ) 0.02 . In the other hand, powder preparation by spray drying has been chosen for an approach to a larger scale process. The sintered ceramics made with these powders present a double microstructure which does not affect the mechanical properties. The presence of cerium oxide produces the following improvements: - increased mobility of the intergranular zirconia inclusions which results in a faster densification; - stabilization of a tetragonal phase without prohibiting the stress induced transformation; - increase of the critical sizes of the tetragonal → monoclinic transformation; - a large decrease in the transformation kinetic in water at 300 deg. C in comparison with that observed for alumina-zirconia doped with yttrium oxide. (author) [fr

  20. 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.

  1. 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)

  2. Low Temperature Synthesis and Properties of Gadolinium-Doped Cerium Oxide Nanoparticles

    DEFF Research Database (Denmark)

    Machado, M. F. S.; Moraes, L. P. R.; Monteiro, N. K.

    2017-01-01

    Gadolinium-doped cerium oxide (GDC) is an attractive ceramic material for solid oxide fuel cells (SOFCs) both as the electrolyte and in composite electrodes operating at low and intermediate temperatures. GDC exhibits high oxygen ion conductivity at a wide range of temperatures and displays a high...... resistance to carbon deposition when hydrocarbons are used as fuels. However, an inconvenience of ceria-based oxides is the high sintering temperature needed to obtain a fully dense ceramic body. In this study, a green chemistry route for the synthesis of 10 mol% GDC nanoparticles is proposed. The aqueous...

  3. Study of cyclic oxidation for stainless steels AISI 309 T 253 M A, with low additions of cerium

    International Nuclear Information System (INIS)

    Velazquez F, G.L.; Martinez, M.; Ruiz, A.

    1998-01-01

    It has been detected that the addition of small amounts (<1%) of the so called 'reactive elements' such as Cerium to Fe-Cr alloys that was utilized in oxidating environment at high temperatures improving its resistance to oxidation under isothermal and cyclic conditions. In this work, it was evaluated the behavior under cyclic oxidation conditions for an austenitic stainless steel at chromium-nickel (253MA) with cerium addition, and comparing it with the AISI 310S austenitic stainless steel. The cyclic oxidation essays consist of five cycles by 24 hours each one, following of a cooling in air until ambient temperature from the temperatures of 850, 900 and 950 Centigrade, registering the gain mass of the specimen at end of each cycle. In order to this were prepared samples with dimensions of 20 mm. x 10 mm. x 1 mm. Later to the oxidation essays was evaluated the morphology of the corrosion products layer by scanning electron microscopy. The present phases were identified by X-ray diffraction and by chemical microanalysis by Dispersive energy (EDAX). The results obtained show that the steel with cerium addition, presents a higher adherence and resistance to the spalling noting that the cerium promotes the casting anchor of the oxides layer to matrix and by reducing the grain size of the layer improving its plasticity. Additionally the cerium promotes the preferential oxidation of the forming elements of protective layers like the chromium. (Author)

  4. Role of epithelial-mesenchymal transition (EMT) and fibroblast function in cerium oxide nanoparticles-induced lung fibrosis

    International Nuclear Information System (INIS)

    Ma, Jane; Bishoff, Bridget; Mercer, R.R.; Barger, Mark; Schwegler-Berry, Diane; Castranova, Vincent

    2017-01-01

    The emission of cerium oxide nanoparticles (CeO 2 ) from diesel engines, using cerium compounds as a catalyst to lower the diesel exhaust particles, is a health concern. We have previously shown that CeO 2 induced pulmonary inflammation and lung fibrosis. The objective of the present study was to investigate the modification of fibroblast function and the role of epithelial-mesenchymal transition (EMT) in CeO 2 -induced fibrosis. Male Sprague-Dawley rats were exposed to CeO 2 (0.15 to 7 mg/kg) by a single intratracheal instillation and sacrificed at various times post-exposure. The results show that at 28 days after CeO 2 (3.5 mg/kg) exposure, lung fibrosis was evidenced by increased soluble collagen in bronchoalveolar lavage fluid, elevated hydroxyproline content in lung tissues, and enhanced sirius red staining for collagen in the lung tissue. Lung fibroblasts and alveolar type II (ATII) cells isolated from CeO 2 -exposed rats at 28 days post-exposure demonstrated decreasing proliferation rate when compare to the controls. CeO 2 exposure was cytotoxic and altered cell function as demonstrated by fibroblast apoptosis and aggregation, and ATII cell hypertrophy and hyperplasia with increased surfactant. The presence of stress fibers, expressed as α-smooth muscle actin (SMA), in CeO 2 -exposed fibroblasts and ATII cells was significantly increased compared to the control. Immunohistofluorescence analysis demonstrated co-localization of TGF-β or α-SMA with prosurfactant protein C (SPC)-stained ATII cells. These results demonstrate that CeO 2 exposure affects fibroblast function and induces EMT in ATII cells that play a role in lung fibrosis. These findings suggest potential adverse health effects in response to CeO 2 nanoparticle exposure. - Highlights: • CeO 2 exposure induced lung fibrosis. • CeO 2 were detected in lung tissue, alveolar type II (ATII) cells and fibroblasts. • CeO 2 caused ATII cell hypertrophy and hyperplasia and altered fibroblast function

  5. Role of epithelial-mesenchymal transition (EMT) and fibroblast function in cerium oxide nanoparticles-induced lung fibrosis

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jane [Health Effects Laboratory Division, NIOSH, Morgantown, WV (United States); Bishoff, Bridget [Mylan Pharmaceuticals, Morganntown, WV (United States); Mercer, R.R.; Barger, Mark; Schwegler-Berry, Diane [Health Effects Laboratory Division, NIOSH, Morgantown, WV (United States); Castranova, Vincent, E-mail: vcastran@hsc.wvu.edu [School of Pharmacy, West Virginia University, Morgantown, WV (United States)

    2017-05-15

    The emission of cerium oxide nanoparticles (CeO{sub 2}) from diesel engines, using cerium compounds as a catalyst to lower the diesel exhaust particles, is a health concern. We have previously shown that CeO{sub 2} induced pulmonary inflammation and lung fibrosis. The objective of the present study was to investigate the modification of fibroblast function and the role of epithelial-mesenchymal transition (EMT) in CeO{sub 2}-induced fibrosis. Male Sprague-Dawley rats were exposed to CeO{sub 2} (0.15 to 7 mg/kg) by a single intratracheal instillation and sacrificed at various times post-exposure. The results show that at 28 days after CeO{sub 2} (3.5 mg/kg) exposure, lung fibrosis was evidenced by increased soluble collagen in bronchoalveolar lavage fluid, elevated hydroxyproline content in lung tissues, and enhanced sirius red staining for collagen in the lung tissue. Lung fibroblasts and alveolar type II (ATII) cells isolated from CeO{sub 2}-exposed rats at 28 days post-exposure demonstrated decreasing proliferation rate when compare to the controls. CeO{sub 2} exposure was cytotoxic and altered cell function as demonstrated by fibroblast apoptosis and aggregation, and ATII cell hypertrophy and hyperplasia with increased surfactant. The presence of stress fibers, expressed as α-smooth muscle actin (SMA), in CeO{sub 2}-exposed fibroblasts and ATII cells was significantly increased compared to the control. Immunohistofluorescence analysis demonstrated co-localization of TGF-β or α-SMA with prosurfactant protein C (SPC)-stained ATII cells. These results demonstrate that CeO{sub 2} exposure affects fibroblast function and induces EMT in ATII cells that play a role in lung fibrosis. These findings suggest potential adverse health effects in response to CeO{sub 2} nanoparticle exposure. - Highlights: • CeO{sub 2} exposure induced lung fibrosis. • CeO{sub 2} were detected in lung tissue, alveolar type II (ATII) cells and fibroblasts. • CeO{sub 2} caused ATII

  6. 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.)

  7. Growth of monodisperse nanocrystals of cerium oxide during synthesis and annealing

    International Nuclear Information System (INIS)

    Ghosh, Swapankumar; Divya, Damodaran; Remani, Kottayilpadi C.; Sreeremya, Thadathil S.

    2010-01-01

    Monodisperse cerium oxide nanocrystals have been successfully synthesised using simple ammonia precipitation technique from cerium(III) nitrate solution at different temperatures in the range 35-80 o C. The activation energy for growth of CeO 2 nanocrystals during the precipitation is calculated as 11.54 kJ/mol using Arrhenius plot. Average crystal diameter was obtained from XRD analysis, HR-TEM and light scattering (PCS). The analysis of size data from HR-TEM images and PCS clearly indicated the formation of highly crystalline CeO 2 particles in narrow size range. CeO 2 nanocrystals precipitated at 35 o C were further annealed at temperatures in the range 300-700 o C. The activation energy for crystal growth during annealing is also calculated and is close to the reported values. An effort is made to predict the mechanism of crystal growth during the precipitation and annealing.

  8. 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.

  9. Low Temperature Synthesis and Properties of Gadolinium-Doped Cerium Oxide Nanoparticles

    DEFF Research Database (Denmark)

    Machado, Marina F. S.; P. R. Moraes, Leticia; Monteiro, Natalia K.

    2017-01-01

    Gadolinium-doped cerium oxide (GDC) is an attractive ceramic material for solid oxide fuel cells (SOFCs) both as the electrolyte or in composite electrodes. The Ni/GDC cermet can be tuned as a catalytic layer, added to the conventional Ni/yttria-stabilized zirconia (YSZ), for the internal steam...... sintering temperature needed to obtain a fully dense ceramic body, which can result in undesired reactions with YSZ. In this study, a green chemistry route for the synthesis of 10 mol% GDC nanoparticles is proposed. Such a low temperature synthesis provides control over particle size and sinterability...

  10. Desulfurization of Diesel Fuel by Oxidation and Solvent Extraction

    Directory of Open Access Journals (Sweden)

    Wadood Taher Mohammed

    2015-02-01

    Full Text Available This research presents a study in ultra-desulfurization of diesel fuel produced from conventional hydro desulfurization process, using oxidation and solvent extraction techniques. Dibenzothiophene (DBT was the organosulfur compound that had been detected in sulfur removal. The oxidation process used hydrogen peroxide as an oxidant and acetic acid as homogeneous catalyst . The solvent extraction process used acetonitrile (ACN and N-methyl – 2 - pyrrolidone (NMP as extractants . Also the effect of five parameters (stirring speed :150 , 250 , 350 , and 450 rpm, temperature (30 , 40 , 45 , and 50 oC, oxidant/simulated diesel fuel ratio (0.5 , 0.75 , 1 , and 1.5 , catalyst/oxidant ratio(0.125,0.25,0.5,and0.75 , and solvent/simulated diesel fuel ratio(0.5,0.6,0.75,and1 were examined as well as solvent type. The results exhibit that the highest removal of sulfur is 98.5% using NMP solvent while it is 95.8% for ACN solvent. The set of conditions that show the highest sulfur removal is: stirring speed of 350 rpm , temperature 50oC , oxidant/simulated diesel fuel ratio 1 , catalyst/oxidant ratio 0.5 , solvent/simulated diesel fuel ratio 1. These best conditions were applied upon real diesel fuel (produced from Al-Dora refinerywith 1000 ppm sulfur content . It was found that sulfur removal was 64.4% using ACN solvent and 75% using NMP solvent.

  11. Influence of annealing on texture properties of cerium oxide thin films

    International Nuclear Information System (INIS)

    Arunkumar, P.; Suresh Babu, K.; Ramaseshan, R.; Dash, S.

    2013-01-01

    Future power demand needs an energy source with higher efficiency, better power density, clean energy and fuel flexibility. Solid oxide fuel cell (SOFC) is one of the potential sources for future needs. Though the polymer and direct methanol based electrolyte are much suitable, for versatile applications (portable devices) they are having major challenges such as design, platinum based catalyst, lower power density and fuel flexibility (free from hydrocarbons). However, in SOFC the high operating temperature is the only major issue. Operating temperature of SOFC could be reduced by proper selection of electrolyte material which should have minimum ionic conductivity of 0.1 Scm -1 at reduced activation energy. This can be achieved by thin film based doped cerium oxide electrolyte for SOFC, leads to Intermediate Temperature Solid Oxide Fuel Cell (ITSOFC). In the present work, we focus on the synthesis of cerium oxide and 20 mol % samarium doped cerium oxide (SDC) nanoparticles by co-precipitation method and to synthesis thin films of the same. Pellets of those powders were heat treated at different temperatures and used as targets for e-beam evaporation to fabricate thin film based electrolyte. Stoichiometry of both powders and thin films were confirmed by XRF and EPMA. GIXRD profiles of ceria and SDC thin films are shown below and a preferred orientation effect is observed in SDC films. In SDC films the X-ray peaks have a shift towards lower angles, due to the difference in ionic radii of Ce 4+ and Sm 3+ . The band gap of CeO 2 (2.88 eV) from optical absorption technique indicates the presence of Ce 3+ with Ce 4+ , indirectly shows the concentration of oxygen vacancies which is required for the thin film electrolyte

  12. Evaluation of mechanically treated cerium (IV) oxides as corrosion inhibitors for galvanized steel

    Energy Technology Data Exchange (ETDEWEB)

    Deflorian, F., E-mail: flavio.deflorian@ing.unitn.it [Department of Materials Engineering and Industrial Technology, University of Trento, Via Mesiano 77, 38123 Trento (Italy); Fedel, M.; Rossi, S. [Department of Materials Engineering and Industrial Technology, University of Trento, Via Mesiano 77, 38123 Trento (Italy); Kamarchik, P. [PPG Industries, Coatings Innovation Center, 4325 Rosanna Drive, Allison Park, PA 15101 (United States)

    2011-09-30

    The use of cerium salts as corrosion inhibitors for hot dip galvanized steel has been object of a numerous studies in the last few years. The role of cerium ions as corrosion inhibitors was proved: cerium is able to block the cathodic sites of the metal, forming insoluble hydroxides and oxides on the zinc surface. This fact leads to a dramatic decrease of the cathodic current densities and, therefore, to a reduction the overall corrosion processes. On the other hand, the potential of cerium oxides as corrosion inhibitors was also proposed. However, the real effectiveness of this kind of anticorrosive pigments has not been clarified yet. In this work cerium (IV) oxides are considered as corrosion inhibitors for galvanized steel. The corrosion inhibition mechanism of mechanically treated (milled) CeO{sub 2} alone and in combination with milled SiO{sub 2} nanoparticles was investigated. For this purpose milled CeO{sub 2}, CeO{sub 2} and SiO{sub 2} milled together and milled SiO{sub 2} particles were studied as corrosion inhibitors in water solution. Therefore, the different mechanically treated particles were dispersed in 0.1 M NaCl solution to test their effectiveness as corrosion inhibitors for galvanized steel. The galvanized steel was immersed in the different solutions and the corrosion inhibition efficiency of the different particles was measured by means of electrochemical techniques. For this purpose, electrochemical impedance spectroscopy (EIS) measurements were carried out, monitoring the evolution of the corrosion processes occurring at the metal surface with the immersion time in the solution. The effect of the different pigments was also investigated by carrying out anodic and cathodic polarization measurements. The polarization curves were acquired under conditions of varied pH. The experimental measurements suggest that the mechanical treatment performed on the SiO{sub 2} and CeO{sub 2} particles promote the formation of an effective corrosion pigment

  13. Effect of coating parameters on the microstructure of cerium oxide conversion coatings

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Benedict Y.; Edington, Joe; O' Keefe, Matthew J

    2003-11-25

    The microstructure and morphology of cerium oxide conversion coatings prepared under different deposition conditions were characterized by transmission electron microscopy (TEM). The coatings were formed by a spontaneous reaction between a water-based solution containing CeCl{sub 3} and aluminum alloy 7075-T6 substrates. Microstructural characterization was performed to determine the crystallinity of the coatings and to obtain a better understanding of the deposition parameters on coating microstructure. The results of TEM imaging and electron diffraction analysis indicated that the as-deposited coating was composed of nanocrystalline particles of a previously unreported cerium compound. The particles of the coatings produced using glycerol as an additive were found to be much finer than those of the coatings prepared in the absence of glycerol. This indicates that glycerol may act as a grain refiner and/or growth inhibitor during coating deposition. After deposition, the coated panels were treated for 5 min in a phosphate sealing solution. The sealing treatment converted the as-deposited coating into hydrated cerium phosphate. Panels coated from solutions containing no glycerol followed by phosphate sealing performed poorly in salt fog tests. With glycerol addition, the corrosion resistance of the coatings that were phosphate sealed improved considerably, achieving an average passing rate of 85%.

  14. Bioavailability of cerium oxide nanoparticles to Raphanus sativus L. in two soils.

    Science.gov (United States)

    Zhang, Weilan; Musante, Craig; White, Jason C; Schwab, Paul; Wang, Qiang; Ebbs, Stephen D; Ma, Xingmao

    2017-01-01

    Cerium oxide nanoparticles (CeO 2 NP) are a common component of many commercial products. Due to the general concerns over the potential toxicity of engineered nanoparticles (ENPs), the phytotoxicity and in planta accumulation of CeO 2 NPs have been broadly investigated. However, most previous studies were conducted in hydroponic systems and with grain crops. For a few studies performed with soil grown plants, the impact of soil properties on the fate and transport of CeO 2 NPs was generally ignored even though numerous previous studies indicate that soil properties play a critical role in the fate and transport of environmental pollutants. The objectives of this study were to evaluate the soil fractionation and bioavailability of CeO 2 NPs to Raphanus sativus L (radish) in two soil types. Our results showed that the silty loam contained slightly higher exchangeable fraction (F1) of cerium element than did loamy sand soil, but significantly lower reducible (F2) and oxidizable (F3) fractions as CeO 2 NPs concentration increased. CeO 2 NPs associated with silicate minerals or the residue fraction (F4) dominated in both soils. The cerium concentration in radish storage root showed linear correlation with the sum of the first three fractions (r 2  = 0.98 and 0.78 for loamy sand and silty loam respectively). However, the cerium content in radish shoots only exhibited strong correlations with F1 (r 2  = 0.97 and 0.89 for loamy sand and silty loam respectively). Overall, the results demonstrated that soil properties are important factors governing the distribution of CeO 2 NPs in soil and subsequent bioavailability to plants. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  15. Development of New Diesel Oxidation and NH3 Slip Catalysts

    DEFF Research Database (Denmark)

    Hansen, Thomas Klint

    Diesel engines used in the transport sector and for other heavy machinery form pollutants during the combustion process. Emission of these pollutants into the atmosphere has harmful consequences on human health and the environment. In order to mitigate these harmful effects, regulations have been...... imposed by environmental protection agencies on the most significant pollutants, including CO, hydrocarbons, NOx, and particulate matter. To reduce emissions to the levels specified by the recent Euro VI regulations, it is necessary to apply catalytic exhaust gas aftertreat-ment systems. A modern diesel...... exhaust aftertreatment system commonly consists of a Pt-based diesel oxidation catalyst (DOC) to oxidize CO and unburnt hydrocarbons to CO2 and H2O, and oxidize NO to NO2. This is followed by the diesel particulate filter (DPF), which entraps particulate matter from the exhaust gas. A solution of urea...

  16. Multifunctional cerium-based nanomaterials and methods for producing the same

    Science.gov (United States)

    O'Keefe, Matthew J.; Castano Londono, Carlos E.; Fahrenholtz, William G.

    2018-01-09

    Embodiments relate to a cerium-containing nano-coating composition, the composition including an amorphous matrix including one or more of cerium oxide, cerium hydroxide, and cerium phosphate; and crystalline regions including one or more of crystalline cerium oxide, crystalline cerium hydroxide, and crystalline cerium phosphate. The diameter of each crystalline region is less than about 50 nanometers.

  17. Cerium oxide nanoparticles stimulate proliferation of primary mouse embryonic fibroblasts in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Popov, Anton L., E-mail: antonpopovleonid@gmail.com [Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region (Russian Federation); Popova, Nelly R. [Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region (Russian Federation); Selezneva, Irina I. [Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region (Russian Federation); Pushchino State Institute of Natural sciences, Pushchino, Moscow region (Russian Federation); Akkizov, Azamat Y. [Kabardino-Balkarian State University, Nalchik (Russian Federation); Ivanov, Vladimir K. [Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); National Research Tomsk State University, Tomsk (Russian Federation)

    2016-11-01

    The increasing application of cell therapy technologies in the treatment of various diseases requires the development of new effective methods for culturing primary cells. The major limitation for the efficient use of autologous cell material is the low rate of cell proliferation. Successful cell therapy requires sufficient amounts of cell material over a short period of time with the preservation of their differentiation and proliferative potential. In this regard, the development of novel, highly efficient stimulators of proliferative activity in stem cells is a truly urgent task. In this paper we have demonstrated that citrate-stabilized cerium oxide nanoparticles (nanoceria) enhance the proliferative activity of primary mouse embryonic fibroblasts in vitro. Cerium oxide nanoparticles stimulate cell proliferation in a wide range of concentrations (10{sup −3} M–10{sup −9} M) through reduction of intracellular levels of reactive oxygen species (ROS) during the lag phase of cell growth and by modulating the expression level of the major antioxidant enzymes. We found the optimal concentration of nanoceria, which provides the greatest acceleration of cell proliferation in vitro, while maintaining the levels of intracellular ROS and mRNA of antioxidant enzymes in the physiological range. Our results confirm that nanocrystalline ceria can be considered as a basis for effective and inexpensive supplements in cell culturing. - Highlights: • Citrate-stabilized cerium oxide nanoparticles are shown to stimulate proliferation of primary embryonic cells in vitro. • Some of mechanisms involved in stimulating of the proliferation by CeO{sub 2} have been uncovered. • The most effective (optimal) concentration of CeO{sub 2} nanoparticles for stimulation of proliferation was determined.

  18. Kinetics and mechanism of the oxidation of cerium in air at ambient temperature

    International Nuclear Information System (INIS)

    Wheeler, D.W.

    2016-01-01

    Highlights: • XRD and transverse sections suggest Ce_2O_3 forms on Ce before being overlaid by CeO_2. • XRD and oxide thickness measurements both indicate linear oxidation. • Extensive cracking on oxide surface which sustains continuing oxidation. • Electron microscopy has shown features indicative of nodular oxidation. • Oxide growth rate determined to be 0.1 μm day"−"1 under the conditions in this study. - Abstract: This paper describes a study of the oxidation of cerium in air at ambient temperature. Specimens were exposed for up to 60 days, during which they were analysed by X-ray diffraction (XRD) at regular intervals. Both XRD and oxide thickness measurements indicate linear oxidation over the duration of this study. Under the conditions employed in this study, the rate of oxide growth has been determined to be 0.1 μm day"−"1. The oxidation process appears to be assisted by extensive cracking in the oxide layer which acts as a non-protective film for the underlying metal.

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

    Energy Technology Data Exchange (ETDEWEB)

    Niroumandrad, S. [Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of); Rostami, M. [Department of Nanomaterials and Nanocoatings, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of); Ramezanzadeh, B., E-mail: ramezanzadeh-bh@icrc.ac.ir [Department of Surface Coatings and Corrosion, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of)

    2015-12-01

    Graphical abstract: - Highlights: • Flaky aluminum pigments were modified with cerium nitrate salt. • pH value of 3.0 was chosen as the optimized pH for the cerium solution. • Corrosion resistance of the pigment significantly increased after modification. • Alkaline pre-treatment prior to modification affected the cerium layer performance. - Abstract: 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 Ce{sub 2}O{sub 3} and CeO{sub 2} 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.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    Graphical abstract: - Highlights: • Flaky aluminum pigments were modified with cerium nitrate salt. • pH value of 3.0 was chosen as the optimized pH for the cerium solution. • Corrosion resistance of the pigment significantly increased after modification. • Alkaline pre-treatment prior to modification affected the cerium layer performance. - Abstract: 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 Ce 2 O 3 and CeO 2 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.

  1. Kinetics of bromide catalysed oxidation of dextrose by cerium (IV) in aqueous sulphuric acid solution

    International Nuclear Information System (INIS)

    Sharma, J.; Sah, M.P.

    1994-01-01

    Kinetics of bromide catalysed oxidation of dextrose by Ce IV in aqueous sulphuric acid medium show first order dependence each in dextrose and cerium(IV). The reaction rate decreases on increasing the concentration of hydrogen ion. The increase in [HSO 4 - ] or [SO 4 2- ] decreases the rate. The bromide ion shows positive catalytic effect on the reaction rate. The value of activation energy has been calculated and a suitable mechanism confirming to the kinetic data is proposed. (author). 3 refs., 3 tabs

  2. Analysis of cerium-composite polymer-electrolyte membranes during and after accelerated oxidative-stability test

    Science.gov (United States)

    Shin, Dongwon; Han, Myungseong; Shul, Yong-Gun; Lee, Hyejin; Bae, Byungchan

    2018-02-01

    The oxidative stability of membranes constructed from a composite of pristine sulfonated poly(arylene ether sulfone) and cerium was investigated by conducting an accelerated oxidative-stability test at the open-circuit voltage (OCV). The membranes were analyzed in situ through OCV and impedance measurements, cyclic voltammetry, and linear-sweep voltammetry to monitor the electrochemical properties during the stability test. Although the high-frequency resistance of a composite membrane was slightly higher than that of a pristine membrane because of the exchange of protons from the sulfonic acid with cerium ions, the composite membrane maintained its potential for much longer than the pristine membrane. The effect of the cerium ions as radical scavengers was confirmed by analyzing the drain water and chemical structure after operation. These post-operation analyses confirmed that cerium ions improved the oxidative stability of the hydrocarbon-based polymer during fuel-cell operation. It is clear that the cerium-based radical scavengers prevented chemical degradation of the polymer membrane as well as the electrode in terms of hydrogen cross-over, polymer-chain scission, and the electrochemical surface area, while they rarely diffused outward from the membrane.

  3. The evolution mechanism of the dislocation loops in irradiated lanthanum doped cerium oxide

    International Nuclear Information System (INIS)

    Miao, Yinbin; Aidhy, Dilpuneet; Chen, Wei-Ying; Mo, Kun; Oaks, Aaron; Wolf, Dieter; Stubbins, James F.

    2014-01-01

    Cerium dioxide, a non-radioactive surrogate of uranium dioxide, is useful for simulating the radiation responses of uranium dioxide and mixed oxide fuel (MOX). Controlled additions of lanthanum can also be used to form various levels of lattice oxide or anion vacancies. In previous transmission electron microscopy (TEM) experimental studies, the growth rate of dislocation loops in irradiated lanthanum doped ceria was reported to vary with lanthanum concentration. This work reports findings of the evolution mechanisms of the dislocation loops in cerium oxide with and without lanthanum dopants based on a combination of molecular statics and molecular dynamics simulations. These dislocation loops are found to be b=1/3〈111〉 interstitial type Frank loops. Calculations of the defect energy profiles of the dislocation loops with different structural configurations and radii reveal the basis for preference of nucleation as well as the driving force of growth. Frenkel pair evolution simulations and displacement cascade overlaps simulations were conducted for a variety of lanthanum doping conditions. The nucleation and growth processes of the Frank loop were found to be controlled by the mobility of cation interstitials, which is significantly influenced by the lanthanum doping concentration. Competition mechanisms coupled with the mobility of cation point defects were discovered, and can be used to explain the lanthanum effects observed in experiments

  4. Effect of polyvinylpyrrolidone on cerium oxide nanoparticle characteristics prepared by a facile heat treatment technique

    Directory of Open Access Journals (Sweden)

    Anwar Ali Baqer

    Full Text Available An aqueous medium composed of polyvinylpyrrolidone (PVP and cerium nitrates at calcination temperature was utilised in the production of cerium oxide (CeO2 semiconductor nanoparticles. A variety of analytical approaches was utilized to examine the structural, morphological and optical characteristics of the resulting nanoparticles. Differential thermal (DTA and thermogravimetric (TGA analyses, indicated that the best calcination temperatures for achieving CeO2 nanoparticle production were more than 485 °C. The results from Fourier-transform infrared (FTIR verified the formation of a crystalline structure after calcination procedures were performed to remove residual organic compounds. Additionally, results from X-ray diffraction (XRD analysis confirmed the cubic fluorite structure of the CeO2 produced. Samples were also analysed by energy dispersive spectroscopy (EDXA which indicated the existence of O and Ce in the samples. Field emission scanning electron microscopy (FESEM was used in the characterisation of nanoparticle morphological features. Transmission electron microscopy (TEM was employed to estimate typical nanoparticle and distribution within sample. This analysis indicated that mean particle sizes were inversely correlated with PVP concentration, with nanoparticle sizes ranging between 12 ± 7 nm at 0.03 g/mL PVP and 6 ± 2 nm at 0.05 g/mL PVP. These results corroborated those obtained by XRD analysis. A UV–vis spectrophotometer was utilised in the demonstration of optical properties and to examine the band gap energy of samples. The potential UV-shielding properties of the nanoparticles were demonstrated by the observed blue shift of the estimated optical energy band, i.e. from 3.35 to 3.43 eV, whilst PL spectra results indicated that decreasing particle size was associated with diminishing photoluminescence intensity. Keywords: Cerium oxide nanoparticles, Heat treatment technique, Structural properties, Optical

  5. Cerium oxide nanoparticles protect rodent lungs from hypobaric hypoxia-induced oxidative stress and inflammation

    Directory of Open Access Journals (Sweden)

    Arya A

    2013-11-01

    Full Text Available Aditya Arya,1 Niroj Kumar Sethy,1 Sushil Kumar Singh,2 Mainak Das,3 Kalpana Bhargava1 1Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences, Defence Research and Development Organization, Delhi, 2Functional Materials Division, Solid State Physics Laboratory, Defence Research and Development Organization, Delhi, 3Biological Science and Bioengineering, Indian Institute of Technology, Kanpur, Uttar Pradesh, India Background: Cerium oxide nanoparticles (nanoceria are effective at quenching reactive oxygen species (ROS in cell culture and animal models. Although nanoceria reportedly deposit in lungs, their efficacy in conferring lung protection during oxidative stress remains unexplored. Thus, the study evaluated the protective efficacy of nanoceria in rat lung tissue during hypobaric hypoxia. Methods: A total of 48 animals were randomly divided into four equal groups (control [C], nanoceria treated [T], hypoxia [H], and nanoceria treated plus hypoxia [T+H]. Animals were injected intraperitoneally with either a dose of 0.5 µg/kg body weight/week of nanoceria (T and T+H groups or vehicle (C and H groups for 5 weeks. After the final dose, H and T+H animals were challenged with hypobaric hypoxia, while C and T animals were maintained at normoxia. Lungs were isolated and homogenate was obtained for analysis of ROS, lipid peroxidation, glutathione, protein carbonylation, and 4-hydroxynonenal-adduct formation. Plasma was used for estimating major inflammatory cytokines using enzyme-linked immunosorbent assay. Intact lung tissues were fixed and both transmission electron microscopy and histopathological examinations were carried out separately for detecting internalization of nanoparticles as well as altered lung morphology. Results: Spherical nanoceria of 7–10 nm diameter were synthesized using a microemulsion method, and the lung protective efficacy of the nanoceria evaluated during hypobaric hypoxia. With repeated

  6. 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.

  7. Kinetics of tetravalent plutonium oxidation by cerium (4)

    Energy Technology Data Exchange (ETDEWEB)

    Nikitina, G P; Shumakov, V G; Egorova, V P

    1975-01-01

    Stoichiometry and kinetics of the Pu(4) + Ce(4) reaction is studied by spectrophotometric method at 5-30 deg C in nitric acid solutions (..mu..=(HNO/sub 3/)+(NaNO/sub 3/) = 1.0 - 5.7; (Ce(4)) = 5.10/sup -5/ - 1.2.10/sup -3/ g-ion/1, (Pu(4)) =1.10/sup -5/ - 8.5.10/sup -4/ g-ion/1. Oxidation of one Pu(4) ion to a hexavalent state requires two Ce(4) ions. The plutonium oxidation is not complicated by by-processes. Reverse Ce(3) + PuO/sub 2//sup +/ reaction does not contribute essentially to the process at (Ce(3)) 2.6.10/sup -2/ g-ion/1. The reaction rate obeys the kinetic equation - d(Pu(4))/dt = ksub(eff)(Pu(4))(Ce(4))/a sub(+-HNO/sub 3/). The thermodynamical activation parameters are found for solutions at the varied nitric acid concentrations:..delta..Gsup(not equal) = 17.0+-0.2 and ..delta..Hsup(not equal) = 21.8+-2 kcal/mole(..mu..=1.0); ..delta..Gsup(not equal) = 19.1+-0.1 and ..delta..Hsup(not equal) = 23.1+-1 kcal/mole(..mu..=4.9). The reaction mechanism is discussed in terms of the theory of absolute reaction rates and the model of long-range charge transfer.

  8. 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.

  9. Oxidation stability of rapeseed biodiesel/petroleum diesel blends

    DEFF Research Database (Denmark)

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

    2016-01-01

    of the oxidation of a biodiesel fuel blend consisting of 30% (v/v) rapeseed methyl ester in petroleum diesel (B30) was conducted at 70 and 90 °C with three aeration rates. Oxidation rates increased with increasing temperature as indicated by decreases in induction period (Rancimat), concentrations of unsaturated...

  10. 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.

  11. Studies on the promotion of nickel—alumina coprecipitated catalysts: III. Cerium oxide

    NARCIS (Netherlands)

    Lansink Rotgerink, H.G.J.; Slaa, J.C.; van Ommen, J.G.; Ross, J.R.H.

    1988-01-01

    Three series of cerium-promoted nickel—alumina catalysts with different nickel-to-aluminium ratios each containing different amounts of cerium have been prepared and characterized. The calcination and reduction behaviour were found not to be altered by the presence of cerium. Part of the promoter

  12. Determination of cerium

    International Nuclear Information System (INIS)

    Stepin, V.V.; Kurbatova, V.I.; Fedorova, N.D.

    1980-01-01

    Techniques of cerium determination in steels and alloys are developed. Amperometric method of determination which is based on Ce(4) titration by a solution of double salt of sulfuric Fe(2) and ammonium when cerium amount exceeds 0.01% is suggested. Cerium is oxidated to tetravalent state by KMnO 4 . The elements interfering with the determination (Cr, Ni etc.) are separated by means of deposition. When cerium content exceeds 0.005% in steels and alloys the determination is carried out using photometric method with arsenazo 3 in hydrochloric medium (pH 1.8-2.3). Optimum concentration is 5-50 μg [ru

  13. Redox-active cerium oxide nanoparticles protect human dermal fibroblasts from PQ-induced damage

    Directory of Open Access Journals (Sweden)

    Claudia von Montfort

    2015-04-01

    Full Text Available Recently, it has been published that cerium (Ce oxide nanoparticles (CNP; nanoceria are able to downregulate tumor invasion in cancer cell lines. Redox-active CNP exhibit both selective pro-oxidative and antioxidative properties, the first being responsible for impairment of tumor growth and invasion. A non-toxic and even protective effect of CNP in human dermal fibroblasts (HDF has already been observed. However, the effect on important parameters such as cell death, proliferation and redox state of the cells needs further clarification. Here, we present that nanoceria prevent HDF from reactive oxygen species (ROS-induced cell death and stimulate proliferation due to the antioxidative property of these particles.

  14. Cerium concentrate and mixed rare earth chloride by the oxidative decomposition of bastnaesite in molten sodium hydroxide

    International Nuclear Information System (INIS)

    Iijima, Toshio; Kato, Kazuhiro; Kuno, Toyohiko; Okuwaki, Akitsugu; Umetsu, Yoshiaki; Okabe, Taijiro

    1993-01-01

    Bastnaesite was treated in molten NaOH at 623-777 K for 10-60 min under atmosphere. Cerium-(III) in the ore was easily oxidized 95% or more within 30 min to give an oxidation product composed of solid solutions of CeO 2 -rich and CeO 2 -lean phases and Ce-free rare earth oxide phase. Simultaneously fluoride ion was removed 97% or more. Cerium concentrate was prepared from the oxidation product by leaching with 0.1-3 M HCl solution. The yield of cerium concentrate and the CeO 2 content reached 55-57% and 70-72%, respectively. Mixed rare earth chloride is composed of about 90% rare earth chloride and 10% alkaline earth chloride, and the contents of CeCl 3 , LaCl 3 , NdCl 3 , and PrCl 3 are 11.5, 58.5, 14.4, and 5.4%, respectively. The particle size of resulting cerium concentrate was fairly uniform and about 0.1 μm

  15. 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...

  16. 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.

  17. 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...

  18. Desulfurization of Diesel Fuel by Oxidation and Solvent Extraction

    OpenAIRE

    Wadood Taher Mohammed; Raghad Fareed Kassim Almilly; Sheam Bahjat Abdulkareem Al-Ali

    2015-01-01

    This research presents a study in ultra-desulfurization of diesel fuel produced from conventional hydro desulfurization process, using oxidation and solvent extraction techniques. Dibenzothiophene (DBT) was the organosulfur compound that had been detected in sulfur removal. The oxidation process used hydrogen peroxide as an oxidant and acetic acid as homogeneous catalyst . The solvent extraction process used acetonitrile (ACN) and N-methyl – 2 - pyrrolidone (NMP) as extractants . Also the ef...

  19. Growth of monodisperse nanocrystals of cerium oxide during synthesis and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Swapankumar, E-mail: swapankumar.ghosh2@mail.dcu.ie; Divya, Damodaran [National Institute for Interdisciplinary Science and Technology (NIIST), Council of Scientific and Industrial Research (CSIR) (India); Remani, Kottayilpadi C. [Sree Neelakanda Government Sanskrit College, Department of Chemistry (India); Sreeremya, Thadathil S. [National Institute for Interdisciplinary Science and Technology (NIIST), Council of Scientific and Industrial Research (CSIR) (India)

    2010-06-15

    Monodisperse cerium oxide nanocrystals have been successfully synthesised using simple ammonia precipitation technique from cerium(III) nitrate solution at different temperatures in the range 35-80 {sup o}C. The activation energy for growth of CeO{sub 2} nanocrystals during the precipitation is calculated as 11.54 kJ/mol using Arrhenius plot. Average crystal diameter was obtained from XRD analysis, HR-TEM and light scattering (PCS). The analysis of size data from HR-TEM images and PCS clearly indicated the formation of highly crystalline CeO{sub 2} particles in narrow size range. CeO{sub 2} nanocrystals precipitated at 35 {sup o}C were further annealed at temperatures in the range 300-700 {sup o}C. The activation energy for crystal growth during annealing is also calculated and is close to the reported values. An effort is made to predict the mechanism of crystal growth during the precipitation and annealing.

  20. 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.

  1. Comparison of the air oxidation behaviors of Zircaloy-4 implanted with yttrium and cerium ions at 500 deg. C

    International Nuclear Information System (INIS)

    Chen, X.W.; Bai, X.D.; Xu, J.; Zhou, Q.G.; Chen, B.S.

    2002-01-01

    As a valuable process for surface modification of materials, ion implantation is eminent to improve mechanical properties, electrochemical corrosion resistance and oxidation behaviors of varieties of materials. To investigate and compare the oxidation behaviors of Zircaloy-4, implantation of yttrium ion and cerium ion were respectively employed by using an MEVVA source at the energy of 40 keV with a dose ranging from 1x10 16 to 1x10 17 ions/cm 2 . Subsequently, weight gain curves of the different specimens including as-received Zircaloy-4 and Zircaloy-4 specimens implanted with the different ions were measured after oxidation in air at 500 deg. C for 100 min. It was obviously found that a significant improvement was achieved in the oxidation behaviors of implanted Zircaloy-4 compared with that of the as-received Zircaloy-4, and the oxidation behavior of cerium-implanted Zircaloy-4 was somewhat better than that of yttrium-implanted specimen. To obtain the valence and the composition of the oxides in the scale, X-ray photoemission spectroscopy was used in the present study. Glancing angle X-ray diffraction, employed to analyze the phase transformation in the oxide films, showed that the addition of yttrium transformed the phase from monoclinic zirconia to tetragonal zirconia, yet the addition of cerium transformed the phase from monoclinic zirconia to hexagonal zirconia. In the end, the mechanism of the improvement of the oxidation behavior was discussed

  2. Effects of ultra-low sulphur diesel fuel and diesel oxidation catalysts on nitrogen dioxide emissions

    International Nuclear Information System (INIS)

    Stachulak, J.S.; Zarling, D.

    2010-01-01

    Diesel oxidation catalysts (DOCs) are used on diesel equipment in underground mines to reduce exhaust emissions of carbon monoxide (CO), hydrocarbons (C) and odour that are associated with gaseous HCs. New catalysts have also been formulated to minimize sulphate production, but little is know about their effects on nitrogen dioxide (NO 2 ) emissions. DOCs are known to oxidize nitric oxide (NO) to NO 2 , which is more toxic than NO at low levels. Vale Inco uses ultra-low sulphur diesel (ULSD) fuel for its underground diesel equipment. Although ULSD is a cleaner burning fuel, its impact on the emissions performance of DOCs is not fully known. Technical material gathered during a literature review suggested that ULSD fuel may increase NO 2 production if DOCs are used, but that the increase would be small. This paper presented the results of a laboratory evaluation of DOCs with varying amounts of time-in service in Vale Inco mines. The 4 Vale Inco DOCs were found to produce excess NO 2 during some test conditions. In both steady-state and transient testing, there were no obvious trends in NO 2 increases with increasing DOC age. Two possibilities for these observations are that the DOCs may have been well within their useful life or their initial compositions differed. Future studies will make use of improved instrumentation, notably NO 2 analyzers, to definitely determine the influence of DOCs on NO 2 formation. 13 refs., 1 tab., 8 figs.

  3. 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.

  4. 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.

  5. Properties of protective oxide scales containing cerium on Incoloy 800H in oxidizing and sulfidizing environments. I. Constant-extension-rate study of mechanical properties

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Fransen, T.; Geerdink, Bert; Gellings, P.J.

    1988-01-01

    The mechanical properties of ceramic coatings containing cerium oxide, prepared by the sol-gel method and used to protect Incoloy 800H against aggressive environments, are reported. Deformation and cracking behavior in oxidizing and sulfidizing environments has been investigated by

  6. 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...

  7. 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 |

  8. Separation of pure Cerium oxides from rare earth compounds. Homogeneous precipitation using Urea-Hydrogen Peroxide

    International Nuclear Information System (INIS)

    Umeda, K.; Abrao, E.

    1975-01-01

    The obtainment of ceric oxide (CeO 2 ) of purity higher than 97% by application of homogeneous precipitation technique is described. The selective separation of cerium was reached by hydrolysis of urea in the presence of hydrogen peroxide, using a rare earths concentrate named rare earths chloride, a natural mixture of all lanthanides provenient from the industrialization of monazite. The best conditions for the preparation of CeO 2 of 94% purity are: 35-70g R 2 O 3 /1 and pH2,0 hydrolysis temperature: 88-90 0 C, urea/R 2 O 3 ratio: 4, H 2 O 2 /Ce 2 O 3 ratio: 1,5-5,0 and hydrolysis duration: 4 hours. A leaching procedure of the precipitate with 0,25-0,75M NHO 3 leads to a product of 97-99,5% CeO 2

  9. Bio-sensing applications of cerium oxide nanoparticles: Advantages and disadvantages.

    Science.gov (United States)

    Charbgoo, Fahimeh; Ramezani, Mohammad; Darroudi, Majid

    2017-10-15

    Cerium oxide nanoparticles (CNPs) contain several properties such as catalytic activity, fluorescent quencher and electrochemical, high surface area, and oxygen transfer ability, which have attracted considerable attention in developing high-sensitive biosensors. CNPs can be used as a whole sensor or a part of recognition or transducer element. However, reports have shown that applying these nanoparticles in sensor design could remarkably enhance detection sensitivity. CNP's outstanding properties in biosensors which go from high catalytic activity and surface area to oxygen transfer and fluorescent quenching capabilities are also highlighted. Herein, we discuss the advantages and disadvantages of CNPs-based biosensors that function through various detection modes including colorimetric, electrochemistry, and chemoluminescent regarding the detection of small organic chemicals, metal ions and biomarkers. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Photocatalytic Degradation of Malachite Green Using Nano-sized cerium-iron Oxide

    Directory of Open Access Journals (Sweden)

    K. L. Ameta

    2014-05-01

    Full Text Available Nano-sized cerium-iron oxide nanoparticles has been synthesized, characterized and explored as an efficient photocatalyst for the photocatalytic degradation of malachite green. The effects of different variables on degradation of dye were optimized such as the pH of the dye solution, dye concentration, amount of photocatalyst and light intensity. About 91% degradation of dye of 2×10-5 M concentration was observed after 2 hours at 8.5 pH and 600 Wm-2 light intensity. The reason for the high catalytic activity of the synthesized nanoparticles is ascribed to the high surface area which determines the active sites of the catalyst and accelerates the photocatalytic degradation.

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

    KAUST Repository

    Zhang, Tao; Li, Weiwei; Croue, Jean-Philippe

    2011-01-01

    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.

  12. 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.

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

    International Nuclear Information System (INIS)

    Tam, Phuong Dinh; Thang, Cao Xuan

    2016-01-01

    This paper developed a label-free immunosensor based on cerium oxide nanowire for Vibrio cholerae O1 detection application. The CeO 2 nanowires were synthesized by hydrothermal reaction. The immobilization of Anti-V. cholerae O1 onto CeO 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) 6 ] 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 2 CFU/mL to 1.0 × 10 4 CFU/mL. The detection limit of the immunosensor was 1.0 × 10 2 CFU/mL. The immunosensor sensitivity was 56.82 Ω/CFU·mL −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 2 CFU/mL to 1.0 × 10 4 CFU/mL. • The detection limit of the immunosensor was 1.0 × 10 2 CFU/mL. • The immunosensor sensitivity was 56.82 Ω/CFU.mL −1 .

  14. 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}.

  15. 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.

  16. Destruction of commercial pesticides by cerium redox couple mediated electrochemical oxidation process in continuous feed mode

    International Nuclear Information System (INIS)

    Balaji, Subramanian; Chung, Sang Joon; Ryu, Jae-Yong; Moon, Il Shik

    2009-01-01

    Mediated electrochemical oxidation was carried out for the destruction of commercial pesticide formulations using cerium(IV) in nitric acid as the mediator electrolyte solution in a bench scale set up. The mediator oxidant was regenerated in situ using an electrochemical cell. The real application of this sustainable process for toxic organic pollutant destruction lies in its ability for long term continuous operation with continuous organic feeding and oxidant regeneration with feed water removal. In this report we present the results of fully integrated MEO system. The task of operating the continuous feed MEO system for a long time was made possible by continuously removing the feed water using an evaporator set up. The rate of Ce(IV) regeneration in the electrochemical cell and the consumption for the pesticide destruction was matched based on carbon content of the pesticides. It was found that under the optimized experimental conditions for Ce(III) oxidation, organic addition and water removal destruction efficiency of ca. 99% was obtained for all pesticides studied. It was observed that the Ce(IV) concentration was maintained nearly the same throughout the experiment. The stable operation for 6 h proved that the process can be used for real applications and for possible scale up for the destruction of larger volumes of toxic organic wastes.

  17. Deep desulfurization of diesel oil oxidized by Fe (VI) systems

    Energy Technology Data Exchange (ETDEWEB)

    Shuzhi Liu; Baohui Wang; Baochen Cui; Lanlan Sun [Daqing Petroleum Institute, Daqing (China). College of Chemistry and Chemical Engineering

    2008-03-15

    Fe (VI) compound, such as K{sub 2}FeO{sub 4}, is a powerful oxidizing agent. Its oxidative potential is higher than KMnO{sub 4}, O{sub 3} and Cl{sub 2}. Oxidation activity of Fe (VI) compounds can be adjusted by modifying their structure and pH value of media. The reduction of Fe (VI), differing from Cr and Mn, results in a relatively non-toxic by-product Fe (III) compounds, which suggests that Fe (VI) compound is an environmentally friendly oxidant. Oxidation of model sulfur compound and diesel oil by K{sub 2}FeO{sub 4} in water-phase, in organic acid and in the presence of phase-transfer catalysts is investigated, respectively. The results show that the activity of oxidation of benzothiophene (BT) and dibenzothiophene (DBT) is low in water-phase, even adding phase-transfer catalyst to the system, because K{sub 2}FeO{sub 4} reacts rapidly with water to form brown Fe(OH){sub 3} to lose ability of oxidation of organic sulfur compounds. The activity of oxidation of the BT and DBT increases markedly in acetic acid. Moreover, the addition of the solid catalyst to the acetic acid medium promotes very remarkably oxidation of organic sulfur compounds. Conversions of the DBT and BT are 98.4% and 70.1%, respectively, under the condition of room temperature, atmospheric pressure, acetic acid/oil (v/v) = 1.0, K{sub 2}FeO{sub 4}/S (mol/mol) = 1.0 and catalyst/K{sub 2}FeO{sub 4} (mol/mol) = 1.0. Under the same condition, diesel oil is oxidized, followed by furfural extraction, the results display sulfur removal rate is 96.7% and sulfur content in diesel oil reduces from 457 ppm to 15.1 ppm. 11 refs., 9 figs., 5 tabs.

  18. Preparation of high-purity cerium nitrate

    International Nuclear Information System (INIS)

    Avila, Daniela Moraes; Silva Queiroz, Carlos Alberto da; Santos Mucillo, Eliana Navarro dos

    1995-01-01

    The preparation of high-purity cerium nitrate has been carried out Cerium oxide has been prepared by fractioned precipitation and ionic exchange techniques, using a concentrate with approximately 85% of cerium oxide from NUCLEMON as raw material. Five sequential ion-exchange columns with a retention capacity of 170 g each have been used. The ethylenediamine-tetraacetic acid (EDTA) was used as eluent. The cerium content has been determined by gravimetry and iodometry techniques. The resulting cerium oxide has a purity > 99%. This material was transformed in cerium nitrate to be used as precursor for the preparation of Zirconia-ceria ceramics by the coprecipitation technique. (author)

  19. Basic study on decontamination of TRU wastes with cerium mediated electrolytic oxidation method

    International Nuclear Information System (INIS)

    Ishii, Junichi; Kobayashi, Fuyumi; Uchida, Shoji; Sumiya, Masato; Kida, Takashi; Shirahashi, Koichi; Umeda, Miki; Sakuraba, Koichi

    2010-03-01

    At Nuclear Fuel Cycle Safety Engineering Research Facility (NUCEF), the cerium mediated electrolytic oxidation method which is a decontamination technique to decrease the radioactivity of TRU wastes to the clearance-level has been developed for the effective reduction of TRU wastes generated from the decommissioning of a nuclear fuel reprocessing facility and so on. This method corrodes the oxide layer and the surface of metallic TRU metal wastes by the strong oxidation power of Ce 4+ in nitric acid. In this study, parameter tests were conducted to optimize the solution condition of Ce 3+ initial concentrations and nitric acid concentrations. The target corrosion rate of metallic TRU wastes set to be 2 - 4 μm/h for the practical use of this method. Under the optimized solution condition, a dissolution test of stainless steel simulating wastes was carried out. From the result of the dissolution test, the average corrosion rate was 3.3 μm/h during the test time of 90 hours. Based on the supposition that the corrosion depth of metallic TRU wastes was 20 μm enough to achieve the clearance-level, the treatment time for the decontamination was about 6 hours. It was confirmed from the result that the decontamination could be performed within one day and the decontamination solution could repeatedly reuse 15 times. (author)

  20. Antioxidative study of Cerium Oxide nanoparticle functionalised PCL-Gelatin electrospun fibers for wound healing application

    Directory of Open Access Journals (Sweden)

    Hilal Ahmad Rather

    2018-06-01

    Full Text Available Skin wound healing involves a coordinated cellular response to achieve complete reepithelialisation. Elevated levels of reactive oxygen species (ROS in the wound environment often pose a hindrance in wound healing resulting in impaired wound healing process. Cerium oxide nanoparticles (CeNPs have the ability to protect the cells from oxidative damage by actively scavenging the ROS. Furthermore, matrices like nanofibers have also been explored for enhancing wound healing. In the current study CeNP functionalised polycaprolactone (PCL-gelatin nanofiber (PGNPNF mesh was fabricated by electrospinning and evaluated for its antioxidative potential. Wide angle XRD analysis of randomly oriented nanofibers revealed ∼2.6 times reduced crystallinity than pristine PCL which aided in rapid degradation of nanofibers and release of CeNP. However, bioactive composite made between nanoparticles and PCL-gelatin maintained the fibrous morphology of PGNPNF upto 14 days. The PGNPNF mesh exhibited a superoxide dismutase (SOD mimetic activity due to the incorporated CeNPs. The PGNPNF mesh enhanced proliferation of 3T3-L1 cells by ∼48% as confirmed by alamar blue assay and SEM micrographs of cells grown on the nanofibrous mesh. Furthermore, the PGNPNF mesh scavenged ROS, which was measured by relative DCF intensity and fluorescence microscopy; and subsequently increased the viability and proliferation of cells by three folds as it alleviated the oxidative stress. Overall, the results of this study suggest the potential of CeNP functionalised PCL-gelatin nanofibrous mesh for wound healing applications.

  1. 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.

  2. 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

  3. Defect states and room temperature ferromagnetism in cerium oxide nanopowders prepared by decomposition of Ce-propionate

    DEFF Research Database (Denmark)

    Mihalache, V.; Grivel, J. C.; Secu, M.

    2018-01-01

    . An improvement of ferromagnetism and intensity of defect-related PL emission was observed when annealing the products in which nanocrystalline cerium oxide coexists with Ce - oxicarbonate traces, Ce2O2CO3. The experimental results were explained based on the following considerations: room temperature......Four batches of cerium oxide powders (with nanocrystallite size of 6.9 nm–572 nm) were prepared from four precursor nanopowders by thermal decomposition of Ce-propionate and annealing in air between 250 °C–1200 °C for 10 min–240 min. Ceria formation reactions, structure, vibrational, luminescence...... and magnetic properties were investigated by differential scanning calorimetry, x-ray diffraction, electron microscopy, infrared spectroscopy, photoluminescence and SQUID. All the samples exhibit room temperature ferromagnetism, RTFM, (with coercivity, Hc, of 8 Oe - 121 Oe and saturation magnetization, Ms...

  4. Effect of calcination temperature on the crystallite growth of cerium oxide nano-powders prepared by the co-precipitation process

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jian-Chih [Department of Orthopaedics, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Chen, Wen-Cheng [School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Tien, Yin-Chun [Department of Orthopaedics, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Shih, Chi-Jen, E-mail: cjshih@kmu.edu.t [Department of Fragrance and Cosmetics Science, Kaohsiung Medical University, 100 Shi-Chuan1st Road, Kaohsiung 80708, Taiwan (China)

    2010-04-30

    Cerium oxide nanocrystallites were synthesized by a co-precipitation process at a relatively low temperature, using cerium (III) nitrate as the starting material in a water solution with pH in the range of 8-9. The effect of calcination temperature on the crystallite growth of cerium oxide nano-powders was investigated by X-ray diffraction, transmission electron microscopy and electron diffraction. The crystallization temperature of the cerium oxide powders was estimated to be about 273 K, by XRD analysis. When calcined at temperatures from 473 to 1273 K, face-centered cubic phase crystallization was observed by XRD. The crystallite size of the cerium oxide increased from 12.0 to 48 nm as the calcining temperature increased from 473 to 1273 K, in the pH range 8-9. The activation energy for the growth of cerium oxide nanoparticles was found to have very low values of 17.5 kJ/mol for pH = 8 and 16.0 kJ/mol for pH = 9.

  5. Study on recovering directly the commercial cerium oxide and total of residue rare earths from Dongpao bastnasite concentrate

    International Nuclear Information System (INIS)

    Nguyen Trong Hung; Nguyen Thanh Chung; Luu Xuan Dinh

    2003-01-01

    A technology for decomposition roasting and sequential leaching processes of Dong Pao bastnasite concentrate to recover directly commercial cerium oxide and total of residue rare earth elements from the leaching solution of the roasted product have been investigated. The bastnasite concentrate is initially roasted at temperature range of 600 - 650 degC and for time of 4 hrs in order to decompose and convert the hardly soluble carbonate forms of ore into easily soluble oxide. The roasted solid is then leached with sulfuric acid solution of 6N at 60 degC for 4 hrs to convert rare earths in oxide and fluoride form into rare earth sulfate. The recovery yield of rare earths of these stages is more than 95%. The attention has especially been paid on recovering directly the commercial cerium oxide and total of residue rare earth element from the above leaching solution. Complex ions of CeSO 4 2+ , Ce(SO 4 ) 2 , Ce(SO 4 ) 3 2- and Ce(SO 4 ) 4 4- exist in aqueous solution of cerium (IV) sulfate. Based on the property, the method of ion - sieve with DOWEX cation resin column has been applied to estimating separation of the ceric complex anions from Ln(III). The survey showed that most of the ceric complex anions are separated from total of residue rare earths. The latter which are absorbed in the cation column are recovered by elution of HCl of 4N. The recovery yield of cerium can only be reached 20% but the purity of that is very high, can be reached 99.6%. About 5 kg of CeO 2 of high grade and 5 kg of TREO of commercial specification have been produced. (author)

  6. Oxidative decarboxylation of glycolic and phenylacetic acids with cerium(4) catalyzed by silver ions in the sulfuric acid media

    International Nuclear Information System (INIS)

    Venkatesvar Rao, G.; Nagardzhun Rao, Ch.; Sajprakash, P.K.

    1981-01-01

    Oxidative decarboxylation of glycolic and phenylacetic acids by cerium (4) in the presence of Ag + ions is studied. The Ce(4) order equals 1, glycolic acid order in the absence of a catalyst also equals 1 and is fractional (0.5) for a catalytic reaction. The phenylacetic acid order is fractional (0.75). The Ag + ion reaction order is fractional and constitutes 0.32 for glycolic and 0.36 for phenylacetic acids. The reaction mechanism is proposed [ru

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

    KAUST Repository

    Nanda, Himansu Sekhar

    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.

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

    KAUST Repository

    Nanda, Himansu Sekhar

    2016-01-01

    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.

  9. 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.

  10. Structure and properties of cerium oxides in bulk and nanoparticulate forms

    International Nuclear Information System (INIS)

    Gangopadhyay, Shruba; Frolov, Dmitry D.; Masunov, Artëm E.; Seal, Sudipta

    2014-01-01

    The experimental and computational studies on the cerium oxide nanoparticles, as well as stoichiometric phases of bulk ceria are reviewed. Based on structural similarities of these phases in hexagonal aspect, electroneutral and non-polar pentalayers are identified as building blocks of type A sesquioxide structure. The idealized core/shell structure of the ceria nanoparticles is described as dioxide core covered by a single pentalayer of sesquioxide, which explains the exceptional stability of subsurface vacancies in nanoceria. The density functional theory (DFT) predictions of the lattice parameters and elastic moduli for the Ce(IV) and Ce(III) oxides at the hybrid DFT level are also presented. The calculated values for both compounds agree with available experimental data and allow predicting changes in the lattice parameter with decreasing size of the nanoparticles. The lattice parameter is calculated as equilibrium between contraction of sesquioxide structure in the core, and expansion of dioxide structure in the shell of the nanoparticle. This is consistent with available XRD data on ceria NPs obtained in mild aqueous conditions. The core/shell model, however, breaks down when applied to the size dependence of lattice parameter in NPs obtained by the laser ablation techniques

  11. Study of oxidation stability of Jatropha curcas biodiesel/ diesel blends

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Siddharth; Sharma, M.P. [Biofuel Research Laboratory, Alternate Hydro Energy Centre, Indian Institute of Technology Roorkee, Uttarakhand- 247667 (India)

    2011-07-01

    Biodiesel production is undergoing rapid technological reforms in industries and academia. This has become more obvious and relevant since the recent increase in the petroleum prices and the growing awareness relating to the environmental consequences of the fuel overdependency. However, the possibilities of production of biodiesel from edible oil resources in India is almost impossible, as primary need is to first meet the demand of edible oil that is already imported therefore it is essential to explore non-edible seed oils, like Jatropha curcas and Pongamia as biodiesel raw materials. The oxidation stability of biodiesel from Jatropha curcas oil is very poor. Therefore the aim of the present paper is to study the oxidation stability of Jatropha curcas biodiesel/ diesel blend. Also the effectiveness of various antioxidants is checked with respect to various blends of biodiesel with diesel.

  12. Emissions of nitrogen oxides and particulates of diesel vehicles

    OpenAIRE

    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 since, despite a continual tightening of European emissions limits, the real-world NOx emissions of new diesel passenger cars and light commercial vehicles have remained virtually unchanged over the la...

  13. Intratracheal instillation of cerium oxide nanoparticles induces hepatic toxicity in male Sprague-Dawley rats

    Directory of Open Access Journals (Sweden)

    Nalabotu SK

    2011-10-01

    Full Text Available Siva K Nalabotu1,2, Madhukar B Kolli1,2, William E Triest3,4, Jane Y Ma5, Nandini DPK Manne2,6, Anjaiah Katta1,2, Hari S Addagarla2, Kevin M Rice2,6–8, Eric R Blough1,2,6,7,91Department of Pharmacology, Physiology and Toxicology, Marshall University, Joan C Edwards School of Medicine; 2Center for Diagnostic Nanosystems, Marshall University; 3Pathology and Laboratory Medicine Service, Veterans Affairs Medical Center; 4Section of Pathology, Department of Anatomy and Pathology, Joan C Edwards School of Medicine, Marshall University, Huntington; 5Health Effects Laboratory Division, NIOSH, Morgantown; 6Department of Biological Sciences; 7School of Kinesiology, College of Health Professions, Marshall University; 8Biotechnology Department, West Virginia State University; 9Department of Cardiology, Joan C Edwards School of Medicine, Marshall University Huntington, WV, USABackground: Cerium oxide (CeO2 nanoparticles have been posited to have both beneficial and toxic effects on biological systems. Herein, we examine if a single intratracheal instillation of CeO2 nanoparticles is associated with systemic toxicity in male Sprague-Dawley rats.Methods and results: Compared with control animals, CeO2 nanoparticle exposure was associated with increased liver ceria levels, elevations in serum alanine transaminase levels, reduced albumin levels, a diminished sodium-potassium ratio, and decreased serum triglyceride levels (P < 0.05. Consistent with these data, rats exposed to CeO2 nanoparticles also exhibited reductions in liver weight (P < 0.05 and dose-dependent hydropic degeneration, hepatocyte enlargement, sinusoidal dilatation, and accumulation of granular material. No histopathological alterations were observed in the kidney, spleen, and heart. Analysis of serum biomarkers suggested an elevation of acute phase reactants and markers of hepatocyte injury in the rats exposed to CeO2 nanoparticles.Conclusion: Taken together, these data suggest that

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

    International Nuclear Information System (INIS)

    Panky, Sreedevi; Thandavan, Kavitha; Sivalingam, Durgajanani; Sethuraman, Swaminathan; Krishnan, Uma Maheswari; Jeyaprakash, Beri Gopalakrishnan; Rayappan, John Bosco Balaguru

    2013-01-01

    Nanostructured cerium oxide (CeO 2 ) thin films were deposited on transparent conducting oxide (TCO) substrate using spray pyrolysis technique with cerium nitrate salt, Ce(NO 3 ) 3 ·6H 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 2 and TCO were found to be 3.2 eV and 2.6 eV respectively. Lipase enzyme was physisorbed on the surface of CeO 2 /TCO film to form the lipase/nano-CeO 2 /TCO bioelectrode. Sensing studies were carried out using cyclic voltammetry and amperometry, with lipase/nano-CeO 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 μM 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 2 /TCO film and hence the lipase/nano-CeO 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 μM with sharp response time of 5 s and a shelf life of about 6

  15. 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

  16. 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.

  17. Correlation of the oxidation state of cerium in sol-gel glasses as a function of thermal treatment via optical spectroscopy and XANES studies.

    Science.gov (United States)

    Assefa, Zerihun; Haire, R G; Caulder, D L; Shuh, D K

    2004-07-01

    Sol-gel glass matrices containing lanthanides have numerous technological applications and their formation involves several chemical facets. In the case of cerium, its ability to exist in two different oxidation states or in mixed valence state provides additional complexities for the sol-gel process. The oxidation state of cerium present during different facets of preparation of sol-gel glasses, and also as a function of the starting oxidation state of cerium added, were studied both by optical spectroscopy and X-ray absorption near-edge structures (XANES). The findings acquired by each approach were compared. The primary focus was on the redox chemistries associated with sample preparation, gelation, and thermal treatment. When Ce3+ is introduced into the starting sols, the trivalent state normally prevails in the wet and room temperature-dried gels. Heating in air at >100 degrees C can generate a light yellow coloration with partial oxidation to the tetravalent state. Above 200 degrees C and up to approximately 1000 degrees C, cerium is oxidized to its tetravalent state. In contrast, when tetravalent cerium is introduced into the sol, both the wet and room temperature-dried gels lose the yellow-brown color of the initial ceric ammonium nitrate solution. When the sol-gel is heated to 110 degrees C it turns yellowish as the cerium tends to be re-oxidized. The yellow color is believed to represent the effect of oxidation and oligomerization of the cerium-silanol units in the matrix. The luminescence properties are also affected by these changes, the details of which are reported herein.

  18. Chemiluminescence behavior based on oxidation reaction of rhodamine B with cerium(IV) in sulfuric acid medium

    International Nuclear Information System (INIS)

    Ma Yongjun; Jin Xiaoyong; Zhou Min; Zhang Ziyu; Teng Xiulan; Chen Hui

    2003-01-01

    The chemiluminescence (CL) of the rhodamine B (RhB)-cerium(IV) system was investigated by flow-injection. Rhodamine B was suggested to be a suitable chemiluminescent reagent in acidic conditions. When the concentration of rhodamine B was 100 mg l -1 and cerium sulfate was 1.6 mmol l -1 in sulfuric acid, the chemiluminescent intensity was found to be highest by using 0.3 mol l -1 sulfuric acid as a carrier solution. The particular chemiluminescent system could tolerate such distinct acidic environments that it was utilized for detecting many compounds that are stable in acidic solutions. Furthermore, by virtue of IR, UV-Vis and luminescence spectroscopic measurements, the chemiluminescent behavior of rhodamine B was studied and a possible mechanism for this chemiluminescent reaction was proposed. The emitter was affirmed to be a radical species due to one of the oxidation products of RhB; the chemiluminescent emissive wavelength was about 425 nm

  19. UV absorption by cerium oxide nanoparticles/epoxy composite thin films

    International Nuclear Information System (INIS)

    Dao, Ngoc Nhiem; Luu, Minh Dai; Nguyen, Quang Khuyen; Kim, Byung Sun

    2011-01-01

    Cerium oxide (CeO 2 ) nanoparticles have been used to modify properties of an epoxy matrix in order to improve the ultra-violet (UV) absorption property of epoxy thin films. The interdependence of mechanical properties, UV absorption property and the dispersed concentration of CeO 2 nanoparticles was investigated. Results showed that, by increasing the dispersed concentration of CeO 2 nanoparticles up to 3 wt%, tensile modulus increases while two other mechanical properties, namely tensile strength and elongation, decrease. The UV absorption peak and the absorption edges of the studied thin films were observed in the UV-Vis absorption spectra. By incorporating CeO 2 nanoparticles into the epoxy matrix, an absorption peak appears at around 318 nm in UV-Vis spectra with increasing CeO 2 concentration from 0.1 to 1.0 wt%. Scanning electron microscopy (SEM) images revealed that a good dispersion of nanoparticles in the epoxy matrix by an ultrasonic method was achieved

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

  1. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Intrinsic and Extrinsic Properties Affecting Innate Immune Responses to Nanoparticles: The Case of Cerium Oxide

    Directory of Open Access Journals (Sweden)

    Eudald Casals

    2017-08-01

    Full Text Available We review the apparent discrepancies between studies that report anti-inflammatory effects of cerium oxide nanoparticles (CeO2 NPs through their reactive oxygen species-chelating properties and immunological studies highlighting their toxicity. We observe that several underappreciated parameters, such as aggregation size and degree of impurity, are critical determinants that need to be carefully addressed to better understand the NP biological effects in order to unleash their potential clinical benefits. This is because NPs can evolve toward different states, depending on the environment where they have been dispersed and how they have been dispersed. As a consequence, final characteristics of NPs can be very different from what was initially designed and produced in the laboratory. Thus, aggregation, corrosion, and interaction with extracellular matrix proteins critically modify NP features and fate. These modifications depend to a large extent on the characteristics of the biological media in which the NPs are dispersed. As a consequence, when reviewing the scientific literature, it seems that the aggregation state of NPs, which depends on the characteristics of the dispersing media, may be more significant than the composition or original size of the NPs. In this work, we focus on CeO2 NPs, which are reported sometimes to be protective and anti-inflammatory, and sometimes toxic and pro-inflammatory.

  3. Electrospun cerium-based TiO2 nanofibers for photocatalytic oxidation of elemental mercury in coal combustion flue gas.

    Science.gov (United States)

    Wang, Lulu; Zhao, Yongchun; Zhang, Junying

    2017-10-01

    Photocatalytic oxidation is an attractive method for Hg-rich flue gas treatment. In the present study, a novel cerium-based TiO 2 nanofibers was prepared and selected as the catalyst to remove mercury in flue gas. Accordingly, physical/chemical properties of those nanofibers were clarified. The effects of some important parameters, such as calcination temperature, cerium dopant content and different illumination conditions on the removal of Hg 0 using the photocatalysis process were investigated. In addition, the removal mechanism of Hg 0 over cerium-based TiO 2 nanofibers focused on UV irradiation was proposed. The results show that catalyst which was calcined at 400 °C exhibited better performance. The addition of 0.3 wt% Ce into TiO 2 led to the highest removal efficiency at 91% under UV irradiation. As-prepared samples showed promising stability for long-term use in the test. However, the photoluminescence intensity of nanofibers incorporating ceria was significantly lower than TiO 2 , which was attributed to better photoelectron-hole separation. Although UV and O 2 are essential factors, the enhancement of Hg 0 removal is more obviously related to the participation of catalyst. The coexistence of Ce 3+ and Ce 4+ , which leads to the efficient oxidation of Hg 0 , was detected on samples. Hg 2+ is the final product in the reaction of Hg 0 removal. As a consequence, the emissions of Hg 0 from flue gas can be significantly suppressed. These indicate that combining photocatalysis technology with cerium-based TiO 2 nanofibers is a promising strategy for reducing Hg 0 efficiently. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. 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

  5. Studies of binary cerium(IV)-praseodymium(IV) and cerium(IV)-terbium(IV) oxides as pigments for ceramic applications

    International Nuclear Information System (INIS)

    Furtado, L.M.L.

    1991-01-01

    It was investigated a series of pigments of general composition Ce 1-x Pr x O 2 , and Ce x Tb y O 2 , exhibiting radish and brown colors, respectively, and high temperature stability. The pigments were obtained by dissolving appropriate amounts of the pure lanthanide oxides in acids and precipitating the rare earths as mixed oxalates, which were isolated and calcined under air, at 1000 0 C. X-Ray powder diffractograms were consistent with a cubic structure for the pigments. Magnetic susceptibility measurements, using Gouy method, indicated the presence of Pr(IV) ions in the Ce 1-x Pr x O 2 pigments and of Terbium predominantly as Tb(III) ions in the Ce-tb mixed oxides. A new method, based on suspension of solid samples in PVA-STB gels (STB = sodium tetradecaborate), was employed for the measurements of the electronic spectra of the pigments. The thermal behaviour the pigments was investigated by the calcination of the oxalates in the temperature range of 500 to 1200 O C, from 10 to 60 minutes. (author)

  6. Magnetic structural effect (MSE in epitaxial films of cerium oxide and lanthanum zirconate

    Directory of Open Access Journals (Sweden)

    Fatima Kh. Chibirova

    2015-06-01

    Full Text Available Increasing the critical current density in the second generation high-temperature superconducting wires (2G HTS is the major challenge for researchers and manufacturers of 2G HTS wires all over the world. We proposed a new approach to increase the number of percolation paths for supercurrent, i.e. increasing the number of low angle grain boundaries (<5° in the epitaxial superconducting YBCO layer by magnetic structural processing (MSP of buffer layers. New experimental results have been presented on the application of MSP for improving the structure and increasing the texture sharpness of buffer in electrical conducting element of 2G HTS wire. The influence of MCO on the structural and textural properties has been investigated in a buffer consisting of epitaxial films of cerium oxide CeO2 and lanthanum zirconate La2Zr2O7 in the CeO2/4La2Zr2O7 architecture. The influence of the magnetic processing of the epitaxial La2Zr2O7 buffer film on the shape of grains has been found. An atomic force microscopical study has shown that after magnetic processing the shape of grains improved significantly. A multilayer CeO2/4La2Zr2O7 buffer each layer of which was processed in a magnetic field has a high degree of orientation: only one diffraction peak with (200 indexes is observed in the X-ray spectrum. The X-ray settings of the (200 diffraction peak indicate a well developed epitaxial structure of CeO2 and La2Zr2O7 layers. The texture of the buffer is by more than 2° sharper than that of the Ni–5 at% W substrate.

  7. 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.

  8. Cerium and rare earth separation process

    International Nuclear Information System (INIS)

    Martin, M.; Rollat, M.

    1986-01-01

    An aqueous solution containing cerium III and rare earths is oxidized in the anodic compartment of an electrolytic cell, cerium IV is extracted by an organic solvent, the organic phase containing Ce IV is reduced in the catodic compartment of the same electrolytic cell and cerium III is extracted in a nitric aqueous phase [fr

  9. Fabrication of Al5083 surface composites reinforced by CNTs and cerium oxide nano particles via friction stir processing

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, S.A. [Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz (Iran, Islamic Republic of); Ranjbar, Khalil, E-mail: k_ranjbar@scu.ac.ir [Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz (Iran, Islamic Republic of); Dehmolaei, R. [Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz (Iran, Islamic Republic of); Amirani, A.R. [12th Ghaem Street, Bld. Hashemzadeh, Shahrak Golestan, Tehran (Iran, Islamic Republic of)

    2015-02-15

    Highlights: • Using friction stir processing, an effect of CNTs and CeO{sub 2} reinforcements on mechanical and corrosion properties of Al5083 alloy is reported. • The strength of Al5083 was increased by 42%, its matrix grain size reduced five times, and hardness was doubled by the incorporation of CNTs-CeO{sub 2} mixture in the volume ratio of 75-25 respectively. • Unlike the CNTs, incorporation of nanosized CeO{sub 2} particles resulted in remarkable increase in pitting resistance of the alloy. - Abstract: In the present investigation, friction stir processing (FSP) was utilized to incorporate Multi Walled Carbon Nano Tubes (MWCNT) and nanosized cerium oxide particles into the matrix of Al5083 alloy to form surface reinforced composites. The effect of these nanosized reinforcements either separately or in the combined form, on microstructural modification, mechanical properties and corrosion resistance of FSPed Al5083 surface composites was studied. A threaded cylindrical hardened steel tool was used with the rotation speeds of 600 and 800 rpm and travel speeds of 35 and 45 mm/min and a tilt angle of 5°. Mechanical properties and corrosion resistance of FSPed samples were evaluated and compared with the base alloy. The maximum tensile strength and hardness value were achieved for the hybrid composite containing a mixture of CNTs and cerium oxide in the volume ratio of 75-25, respectively, whereas a significant increase in pitting resistance of the base alloy was obtained when cerium oxide alone was incorporated. The corrosion behavior of the samples was investigated by potentiodynamic polarization tests and assessed in term of pitting potential and passivation range. Microstructural analysis carried out by using optical and electron microscopes showed that reinforcements are well dispersed inside the nugget zone (NZ), and remarkable grain refinement is gained. The study was aimed to fabricate surface composites with improved mechanical properties and

  10. 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......The influence of hydroxyl content of binders on rheological properties of screen printing inks is investigated. The actual amount of hydroxyl groups is correlated to the level of hyper-entanglement that characterizes the binders in solution. Three of the most used binders (ethyl cellulose, and two...

  11. Prophylactic Treatment with Cerium Oxide Nanoparticles Attenuate Hepatic Ischemia Reperfusion Injury in Sprague Dawley Rats

    Directory of Open Access Journals (Sweden)

    Nandini D.P.K. Manne

    2017-07-01

    Full Text Available Background: Hepatic ischemia reperfusion is one the main causes for graft failure following transplantation. Although, the molecular events that lead to hepatic failure following ischemia reperfusion (IR are diverse and complex, previous studies have shown that excessive formation of reactive oxygen species (ROS are responsible for hepatic IR injury. Cerium oxide (CeO2 nanoparticles have been previously shown to act as an anti-oxidant and anti-inflammatory agent. Here, we evaluated the protective effects of CeO2 nanoparticles on hepatic ischemia reperfusion injury. Methods: Male Sprague Dawley rats were randomly assigned to one of the four groups: Control, CeO2 nanoparticle only, hepatic ischemia reperfusion (IR group and hepatic ischemia reperfusion (IR plus CeO2 nanoparticle group (IR+ CeO2. Partial warm hepatic ischemia was induced in left lateral and median lobes for 1h, followed by 6h of reperfusion. Animals were sacrificed after 6h of reperfusion and blood and tissue samples were collected and processed for various biochemical experiments. Results: Prophylactic treatment with CeO2 nanoparticles (0.5mg/kg i.v (IR+CeO2 group 1 hour prior to hepatic ischemia and subsequent reperfusion injury lead to a decrease in serum levels of alanine aminotransaminase and lactate dehydrogenase at 6 hours after reperfusion. These changes were accompanied by significant decrease in hepatocyte necrosis along with reduction in several serum inflammatory markers such as macrophage derived chemokine, macrophage inflammatory protein-2, KC/GRO, myoglobin and plasminogen activator inhibitor-1. However, immunoblotting demonstrated no significant changes in the levels of apoptosis related protein markers such as bax, bcl2 and caspase 3 in IR and IR+ CeO2 groups at 6 hours suggesting necrosis as the main pathway for hepatocyte death. Conclusion: Taken together, these data suggest that CeO2 nanoparticles attenuate IR induced cell death and can be used as a prophylactic

  12. Oxidative Stress, Inflammation, and DNA Damage Responses Elicited by Silver, Titanium Dioxide, and Cerium Oxide Nanomaterials

    Science.gov (United States)

    Previous literature on the biological effects of engineered nanomaterials has focused largely on oxidative stress and inflammation endpoints without further investigating potential pathways. Here we examine time-sensitive biological response pathways affected by engineered nanoma...

  13. Co/Zr substitution in a cerium-zirconium oxide by catalytic steam reforming of bio-ethanol

    International Nuclear Information System (INIS)

    Vargas, J.C.; Thomas, S.; Roger, A.C.; Kiennemann, A.; Vargas, J.C.

    2006-01-01

    This work deals with the production of hydrogen by bio-ethanol catalytic steam reforming. The aim is to develop a catalyst active in ethanol conversion, selective in hydrogen and resistant to deactivation, particularly those induced by the formation of carbon deposition. The metal-support interaction being one of the keys of this challenge, catalysts in which a transition metal is inserted into an oxide by a liquid synthesis method (by the precursor method) have been developed. The initial insertion of cobalt into a cerium oxide-zirconia structure presents the advantages to increase the redox properties of the host oxide and to allow a stable reduction of a cobalt part while favoring the metal-support interaction. (O.M.)

  14. Synthesis of cerium oxide catalysts supported on MCM-41 molecular sieve; Sintese de catalisadores de oxido de cerio suportados na peneira molecular MCM-41

    Energy Technology Data Exchange (ETDEWEB)

    Souza, E.L.S.; Barros, T.R.B.; Sousa, B.V. de, E-mail: emylle.souza@gmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia Quimica

    2016-07-01

    Porous materials have been widely studied as catalysts and catalyst support. The MCM-41 structure is the one that has been most studied because of its application possibilities in chemical processes. This work aimed to obtain and characterize cerium oxide catalysts supported on MCM-41 molecular sieve. The molecular sieve was synthesized by the conventional method with the following molar composition: 1 SiO2: 0.30 CTABr: NH3 11: 144 H2O. Then, 25% w/w cerium was incorporated into the MCM-41 using the wet impregnation process and the material obtained was activated by calcination. From the XRD patterns was confirmed the structure of the molecular sieve, and were identified the cerium oxide phases in its structure. The textural catalysts characteristics were investigated by isotherms of N2 adsorption/desorption (BET method). (author)

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    Graphical abstract: - Highlights: • Supported Ce-Gd-oxides are applied for soot oxidation for the first time. • Gd 2 O 3 doping facilitates enhanced extrinsic oxygen vacancy concentration in ceria. • The Ce-Gd/TiO 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 2 O 3 , SiO 2 , and TiO 2 supports in modulating the catalytic performance of ceria-based solid solutions. In this study, we prepared nanosized Ce-Gd/Al 2 O 3 , Ce-Gd/SiO 2 , and Ce-Gd/TiO 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 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 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 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 2 catalyst exhibited the highest activity, suggesting the existence of strong interfacial metal support interaction between the active metal oxide and the support

  16. 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.

  17. Synthesis and performance of cerium oxide as anode materials for lithium ion batteries by a chemical precipitation method

    International Nuclear Information System (INIS)

    Liu, Haowen; Le, Qi

    2016-01-01

    In this present work, chemical precipitation method was employed for preparing cerium oxide. XRD, SEM, TEM, TGA/DTA and BET were used to investigate the structure, shape and formation mechanism, respectively. No impurities were detected. It was found that alcohol had obvious effection on the growth of the final sample. The shape of the precursor was retained after calcined at 500 °C. This result led to the possibility of an easy scale up to a commercial process. EIS and charge–discharge tests were carried out by using the as-prepared CeO_2 as an anode material for lithium ion batteries. Specially, the initial discharge specific capacity of the rhombus CeO_2 was about 529 mAh g"−"1 and stabilized reversibly at about 374 mAh g"−"1 after 50 cycles. It showed a promising usage as anode materials in lithium ion battery. - Highlights: • Chemical precipitation method was employed for the synthesis of cerium oxide. • Alcohol has obvious effection on the growth of the final sample. • The rhombus CeO_2 showed the better electrochemical properties as anode of lithium ion batteries.

  18. Synthesis and performance of cerium oxide as anode materials for lithium ion batteries by a chemical precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Haowen, E-mail: liuhwchem@hotmail.com; Le, Qi

    2016-06-05

    In this present work, chemical precipitation method was employed for preparing cerium oxide. XRD, SEM, TEM, TGA/DTA and BET were used to investigate the structure, shape and formation mechanism, respectively. No impurities were detected. It was found that alcohol had obvious effection on the growth of the final sample. The shape of the precursor was retained after calcined at 500 °C. This result led to the possibility of an easy scale up to a commercial process. EIS and charge–discharge tests were carried out by using the as-prepared CeO{sub 2} as an anode material for lithium ion batteries. Specially, the initial discharge specific capacity of the rhombus CeO{sub 2} was about 529 mAh g{sup −1} and stabilized reversibly at about 374 mAh g{sup −1} after 50 cycles. It showed a promising usage as anode materials in lithium ion battery. - Highlights: • Chemical precipitation method was employed for the synthesis of cerium oxide. • Alcohol has obvious effection on the growth of the final sample. • The rhombus CeO{sub 2} showed the better electrochemical properties as anode of lithium ion batteries.

  19. The impact of cerium oxide nanoparticles on the physiology of soybean (Glycine max (L.) Merr.) under different soil moisture conditions.

    Science.gov (United States)

    Cao, Zhiming; Rossi, Lorenzo; Stowers, Cheyenne; Zhang, Weilan; Lombardini, Leonardo; Ma, Xingmao

    2018-01-01

    The ongoing global climate change raises concerns over the decreasing moisture content in agricultural soils. Our research investigated the physiological impact of two types of cerium oxide nanoparticles (CeO 2 NPs) on soybean at different moisture content levels. One CeO 2 NP was positively charged on the surface and the other negatively charged due to the polyvinylpyrrolidone (PVP) coating. The results suggest that the effect of CeO 2 NPs on plant photosynthesis and water use efficiency (WUE) was dependent upon the soil moisture content. Both types of CeO 2 NPs exhibited consistently positive impacts on plant photosynthesis at the moisture content above 70% of field capacity (θ fc ). Similar positive impact of CeO 2 NPs was not observed at 55% θ fc , suggesting that the physiological impact of CeO 2 NPs was dependent upon the soil moisture content. The results also revealed that V Cmax (maximum carboxylation rate) was affected by CeO 2 NPs, indicating that CeO 2 NPs affected the Rubisco activity which governs carbon assimilation in photosynthesis. In conclusion, CeO 2 NPs demonstrated significant impacts on the photosynthesis and WUE of soybeans and such impacts were affected by the soil moisture content. Graphical abstract Soil moisture content affects plant cerium oxide nanoparticle interactions.

  20. 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. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. 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.

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

    KAUST Repository

    Yang, Seung Yeon; Naser, Nimal; Chung, Suk-Ho; Al-Qurashi, Khalid

    2014-01-01

    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.

  3. 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.

  4. Oxidative desulfurization of diesel with TBHP/isobutyl aldehyde/air oxidation system

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Wei; Wang, Chengyong; Lin, Peng; Lu, Xiaoping [Institute of Sonochemical Engineering, Nanjing University of Technology, Nanjing 210009, Jiangsu (China)

    2011-01-15

    Oxidative desulfurization of hydrogenation diesel (40 mL) was studied using air as oxidant, tert-butyl hydroperoxide (TBHP) as radical initiator at ambient pressure and moderate temperature in the presence of isobutyl aldehyde. TBHP could accelerate the production of carbonyl radical and its peroxidation. When the molar fraction of TBHP was 5 mmol, the conversion of DBT could reach 96.1% in the present of 20 mmol isobutyl aldehyde and air, which was more than that of 85.5% without initiator. The air was an effective oxidant and acetonitrile was an optimal solvent in this process. The sulfur content of the hydrogenation diesel could be reduced from 403 to 13 ppm (96.8% removed) under the synergistic effect of air, TBHP and isobutyl aldehyde. (author)

  5. 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.

  6. 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

  7. One-step synthesis and characterizations of cerium oxide nanoparticles in an ambient temperature via Co-precipitation method

    Science.gov (United States)

    Pujar, Malatesh S.; Hunagund, Shirajahammad M.; Desai, Vani R.; Patil, Shivaprasadgouda; Sidarai, Ashok H.

    2018-04-01

    We report the simple Co-precipitation method for the synthesis of Cerium oxide (CeO2) nanoparticles (NPs) in an ambient temperature. We have taken the Cerium (III) nitrate hexahydrate (Ce(NO3)3.6H2O) and Sodium hydroxide (NaOH) as the precursors. The obtained NPs were analyzed using the UV-Vis spectrophotometer, Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The obtained results signify that UV-Vis spectrum exhibited a well-defined absorption peak at 274 nm and the estimated energy gap (Eg) is 4.05 eV. The FT-IR analysis provides the supporting evidence for the presence of bonding of O-H, nitrates, alcohols and O-Ce-O vibrations. The XRD result reveals that the synthesized CeO2 NPs was crystallite with cubic phase structure and the estimated average crystallite size of CeO2 NPs using Scherer's and W-H method was significantly different due to their assumptions. Further, it is purposed to study their photocatalytic biological activities.

  8. Chemiluminescence behavior based on oxidation reaction of rhodamine B with cerium(IV) in sulfuric acid medium

    Energy Technology Data Exchange (ETDEWEB)

    Ma Yongjun; Jin Xiaoyong; Zhou Min; Zhang Ziyu; Teng Xiulan; Chen Hui

    2003-08-18

    The chemiluminescence (CL) of the rhodamine B (RhB)-cerium(IV) system was investigated by flow-injection. Rhodamine B was suggested to be a suitable chemiluminescent reagent in acidic conditions. When the concentration of rhodamine B was 100 mg l{sup -1} and cerium sulfate was 1.6 mmol l{sup -1} in sulfuric acid, the chemiluminescent intensity was found to be highest by using 0.3 mol l{sup -1} sulfuric acid as a carrier solution. The particular chemiluminescent system could tolerate such distinct acidic environments that it was utilized for detecting many compounds that are stable in acidic solutions. Furthermore, by virtue of IR, UV-Vis and luminescence spectroscopic measurements, the chemiluminescent behavior of rhodamine B was studied and a possible mechanism for this chemiluminescent reaction was proposed. The emitter was affirmed to be a radical species due to one of the oxidation products of RhB; the chemiluminescent emissive wavelength was about 425 nm.

  9. Structural analysis of nickel doped cerium oxide catalysts for fuel reforming in solid oxide fuel cells

    Science.gov (United States)

    Cavendish, Rio

    As world energy demands increase, research into more efficient energy production methods has become imperative. Heterogeneous catalysis and nanoscience are used to promote chemical transformations important for energy production. These concepts are important in solid oxide fuel cells (SOFCs) which have attracted attention because of their potential to provide an efficient and environmentally favorable power generation system. The SOFC is also fuel-flexible with the ability to run directly on many fuels other than hydrogen. Internal fuel reforming directly in the anode of the SOFC would greatly reduce the cost and complexity of the device. Methane is the simplest hydrocarbon and a main component in natural gas, making it useful when testing catalysts on the laboratory scale. Nickel (Ni) and gadolinium (Gd) doped ceria (CeO 2) catalysts for potential use in the SOFC anode were synthesized with a spray drying method and tested for catalytic performance using partial oxidation of methane and steam reforming. The relationships between catalytic performance and structure were then investigated using X-ray diffraction, transmission electron microscopy, and environmental transmission electron microscopy. The possibility of solid solutions, segregated phases, and surface layers of Ni were explored. Results for a 10 at.% Ni in CeO2 catalyst reveal a poor catalytic behavior while a 20 at.% Ni in CeO2 catalyst is shown to have superior activity. The inclusion of both 10 at.% Gd and 10 at.% Ni in CeO2 enhances the catalytic performance. Analysis of the presence of Ni in all 3 samples reveals Ni heterogeneity and little evidence for extensive solid solution doping. Ni is found in small domains throughout CeO2 particles. In the 20 at.% Ni sample a segregated, catalytically active NiO phase is observed. Overall, it is found that significant interaction between Ni and CeO2 occurs that could affect the synthesis and functionality of the SOFC anode.

  10. Unusual kinetics of poly(ethylene glycol) oxidation with cerium(IV) ions in sulfuric acid medium and implications for copolymer synthesis.

    Science.gov (United States)

    Szymański, Jan K; Temprano-Coleto, Fernando; Pérez-Mercader, Juan

    2015-03-14

    The cerium(IV)-alcohol couple in an acidic medium is an example of a redox system capable of initiating free radical polymerization. When the alcohol has a polymeric nature, the outcome of such a process is a block copolymer, a member of a class of compounds possessing many useful properties. The most common polymer with a terminal -OH group is poly(ethylene glycol) (PEG); however, the detailed mechanism of its reaction with cerium(IV) remains underexplored. In this paper, we report our findings for this reaction based on spectrophotometric measurements and kinetic modeling. We find that both the reaction order and the net rate constant for the oxidation process depend strongly on the nature of the acidic medium used. In order to account for the experimental observations, we postulate that protonation of PEG decreases its affinity for some of the cerium(IV)-sulfate complexes formed in the system.

  11. Probing and tuning the size, morphology, chemistry and structure of nanoscale cerium oxide

    Science.gov (United States)

    Kuchibhatla, Satyanarayana Vnt

    Cerium oxide (ceria)-based materials in the nanoscale regime are of significant fundamental and technological interest. Nanoceria in pure and doped forms has current and potential use in solid oxide fuel cells, catalysis, UV-screening, chemical mechanical planarization, oxygen sensors, and bio-medical applications. The characteristic feature of Ce to switch between the +3 and +4 oxidation states renders oxygen buffering capability to ceria. The ease of this transformation was expected to be enhanced in the nanoceria. In most the practical scenarios, it is necessary to have a stable suspension of ceria nanoparticles (CNPs) over longer periods of time. However, the existing literature is confined to short term studies pertaining to synthesis and property evaluation. Having understood the need for a comprehensive understanding of the CNP suspensions, this dissertation is primarily aimed at understanding the behavior of CNPs in various chemical and physical environments. We have synthesized CNPs in the absence of any surfactants at room temperature and studied the aging characteristics. After gaining some understanding about the behavior of this functional oxide, the synthesis environment and aging temperature were varied, and their affects were carefully analyzed using various materials analysis techniques such as high resolution transmission electron microscopy (HRTEM), UV-Visible spectroscopy (UV-Vis), and X-ray photoelectron spectroscopy (XPS). When the CNPs were aged at room temperature in as-synthesized condition, they were observed to spontaneously assemble and evolve as fractal superoctahedral structures. The reasons for this unique polycrystalline morphology were attributed to the symmetry driven assembly of the individual truncated octahedral and octahedral seed of the ceria. HRTEM and Fast Fourier Transform (FFT) analyses were used to explain the agglomeration behavior and evolution of the octahedral morphology. Some of the observations were supported by

  12. 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.

  13. The iron and cerium oxide influence on the electric conductivity and the corrosion resistance of anodized aluminium

    International Nuclear Information System (INIS)

    Souza, Kellie Provazi de

    2006-01-01

    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 4 ) 2 (NH 4 ) 2 .6H 2 O electrolyte composition was changed with the addition of boric and ascorbic acids. To the sealing treatment the CeCl 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)

  14. Influence of cerium, zirconium and boron on the oxidation resistance of heat-resistant steels in air

    International Nuclear Information System (INIS)

    Gala, A.; Schendler, W.

    1981-01-01

    Isothermal and cyclic oxidation experiments were carried out in air to investigate the influence of the minor elements such as Cerium, Zirkonium and Boron on the oxidation resistance of heat resistant ferritic and austenitic steels like X10Cr18, X10CrAl18 and X15CrNiSi2012. In the case of cyclicexperiments samples were exposed at constant temperatures for 100 h and then cooled to R.T. This cycle was repeated 10 times. The corrosion was determined as weight change and was continuously measured by a thermo-balance. The distribution of the alloying elements on the phase boundary scale/steel was examined by Scanning-Electron-Microscope. Addition of small amounts of Ce (0.3 wt-% max.) could reduce the oxidation rate in the case of isothermal and cyclic conditions. Zirkonium concentrations below 0.1 wt-% could have a beneficial effect, but at higher concentrations the oxidation rate increases with increasing amounts of Zr. Small Boron concentrations of 0.02 wt-% lead to catastrophic oxidation at temperatures above 1000 0 C. (orig.) [de

  15. Effect of additions of cerium, lanthanum, and zirconium on the state of plantinum and the activity of aluminoplatinum catalysts for the complete oxidation of hydrocarbons

    International Nuclear Information System (INIS)

    Drozdov, V.A.; Davydov, A.A.; Popovskii, V.V.; Tsyrul'nikov, P.G.

    1986-01-01

    It is shown from an analysis of the diffuse reflectance spectra that additions of cerium, lanthanum or zirconium to aluminoplatinum catalyst stabilize the platinum in an oxidized state. This leads to a change in the specific catalytic activity (SCA) towards the total oxidation of methane and butane. The SCA of modified, reduced samples is greater than the SCA of samples that were calcined in air. This is because of the greater activity of metallic platinum compared to the ionic form

  16. Oxidation of diesel soot on binary oxide CuCr(Co)-based monoliths.

    Science.gov (United States)

    Soloviev, Sergiy O; Kapran, Andriy Y; Kurylets, Yaroslava P

    2015-02-01

    Binary oxide systems (CuCr2O4, CuCo2O4), deposited onto cordierite monoliths of honeycomb structure with a second support (finely dispersed Al2O3), were prepared as filters for catalytic combustion of diesel soot using internal combustion engine's gas exhausts (O2, NOx, H2O, CO2) and O3 as oxidizing agents. It is shown that the second support increases soot capacity of aforementioned filters, and causes dispersion of the particles of spinel phases as active components enhancing thereby catalyst activity and selectivity of soot combustion to CO2. Oxidants used can be arranged with reference to decreasing their activity in a following series: O3≫NO2>H2O>NO>O2>CO2. Ozone proved to be the most efficient oxidizing agent: the diesel soot combustion by O3 occurs intensively (in the presence of copper chromite based catalyst) even at closing to ambient temperatures. Results obtained give a basis for the conclusion that using a catalytic coating on soot filters in the form of aforementioned binary oxide systems and ozone as the initiator of the oxidation processes is a promising approach in solving the problem of comprehensive purification of automotive exhaust gases at relatively low temperatures, known as the "cold start" problem. Copyright © 2014. Published by Elsevier B.V.

  17. 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.

  18. Deep desulfurization of diesel via peroxide oxidation using phosphotungstic acid as phase transfer catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Sachdeva, T.O.; Pant, K.K. [Department of Chemical Engineering, Indian Institute of Technology, Delhi, New Delhi, 110016 (India)

    2010-09-15

    High sulfur level in diesel fuel has been identified as a major contributor to air pollutant in term of sulfur dioxide (SO{sub x}) through diesel fueled vehicles. The main aim of the present work is to develop a promising methodology for ultra deep desulfurization of diesel fuel using oxidation followed by phase transfer of oxidized sulfur. Experiments were carried out in a batch reactor using n-decane as the model diesel compound and also using commercial diesel feedstock. To remove sulfur tetraoctylammonium bromide, phosphotungstic acid, and hydrogen peroxide were used as phase transfer agent, catalyst and oxidant respectively. The percent sulfur removal increases with increasing the initial concentration of sulfur in fuel and with increasing the reaction temperature. Similar trends were observed when commercial diesel was used to carry out desulfurization studies. The amphiphilic catalyst serves as a catalyst and also as an emulsifying agent to stabilize the emulsion droplets. The effects of temperature, agitation speed, quantity of catalyst and the phase transfer agent were studied to estimate the optimal conditions for the reactions. The sulfur removal from a commercial diesel by phase transfer catalysis has been found effective and removal efficiency was more than 98%. Kinetic experiments carried out for the desulfurization revealed that the sulfur removal results are best fitted to a pseudo first order kinetics and the apparent activation energy of desulfurization was 30.6 kJ/mol. (author)

  19. Deep desulfurization of diesel via peroxide oxidation using phosphotungstic acid as phase transfer catalyst

    International Nuclear Information System (INIS)

    Sachdeva, T.O.; Pant, K.K.

    2010-01-01

    High sulfur level in diesel fuel has been identified as a major contributor to air pollutant in term of sulfur dioxide (SO x ) through diesel fueled vehicles. The main aim of the present work is to develop a promising methodology for ultra deep desulfurization of diesel fuel using oxidation followed by phase transfer of oxidized sulfur. Experiments were carried out in a batch reactor using n-decane as the model diesel compound and also using commercial diesel feedstock. To remove sulfur tetraoctylammonium bromide, phosphotungstic acid, and hydrogen peroxide were used as phase transfer agent, catalyst and oxidant respectively. The percent sulfur removal increases with increasing the initial concentration of sulfur in fuel and with increasing the reaction temperature. Similar trends were observed when commercial diesel was used to carry out desulfurization studies. The amphiphilic catalyst serves as a catalyst and also as an emulsifying agent to stabilize the emulsion droplets. The effects of temperature, agitation speed, quantity of catalyst and the phase transfer agent were studied to estimate the optimal conditions for the reactions. The sulfur removal from a commercial diesel by phase transfer catalysis has been found effective and removal efficiency was more than 98%. Kinetic experiments carried out for the desulfurization revealed that the sulfur removal results are best fitted to a pseudo first order kinetics and the apparent activation energy of desulfurization was 30.6 kJ/mol. (author)

  20. Ultrasound assisted green synthesis of cerium oxide nanoparticles using Prosopis juliflora leaf extract and their structural, optical and antibacterial properties

    Directory of Open Access Journals (Sweden)

    Arunachalam Thirunavukkarasu

    2018-03-01

    Full Text Available Cerium oxide nanoparticles (CONPs were prepared using ultrasound assisted leaf extract of Prosopis juliflora acting as a reducing as well as stabilizing agent. The synthesized CONPs were characterized by ultraviolet-visible absorption spectroscopy (UV-Vis, particle size analyzer (PSA, Fourier transform infrared spectroscopy (FT-IR, Raman spectroscopy, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS and high-resolution transmission electron microscopy (HRTEM. From the UV-Vis analysis, the optical band gap of the prepared CONPs (Eg = 3.62 eV was slightly increased as compared to the bulk ceria (Eg = 3.19 eV. The phytochemicals in the extract reduced the particle size to 3.7 nm ± 0.3 nm, as it is evident from the PSA. FT-IR results confirmed the Ce-O stretching bands by showing the peaks at 452 cm-1. The Raman spectrumshowed a characteristic peak shift for CONPs at 461.2 cm-1. XRD analysis revealed the cubic fluorite structure of the synthesizednanoparticles with the lattice constant, a of 5.415 Å and unit cell volume, V of 158.813 Å3. XPS signals were used to determine the concentration of Ce3+ and Ce4+ in the prepared CONPs and it was found that major amount of cerium exist in the Ce4+ state. HRTEM images showed spherical shaped particles with an average size of 15 nm. Furthermore, the antibacterial activity of the prepared CONPs was evaluated and their efficacies were compared with the conventional antibiotics using disc diffusion assay against a set of Gram positive (G+ bacteria (Staphylococcus aureus, Streptococcus pneumonia and Gram negative (G- bacteria (Pseudomonas aeruginosa, Proteus vulgaris. The results suggested that CONPs showed antibacterial activity with significant variations due to the differences in the membrane structure and cell wall composition among the two groups tested.

  1. ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF MOBILE SOURCE EMISSIONS CONTROL DEVICES/CLEAN DIESEL TECHNOLOGIES FUEL BORNE CATALYST WITH CLEANAIR SYSTEM'S DIESEL OXIDATION CATALYST

    Science.gov (United States)

    The Environmental Technology Verification report discusses the technology and performance of the Fuel-Borne Catalyst with CleanAir System's Diesel Oxidation Catalyst manufactured by Clean Diesel Technologies, Inc. The technology is a fuel-borne catalyst used in ultra low sulfur d...

  2. Amorphous saturated Cerium-Tungsten-Titanium oxide nanofibers catalysts for NOx selective catalytic reaction

    DEFF Research Database (Denmark)

    Dankeaw, Apiwat; Gualandris, Fabrizio; Silva, Rafael Hubert

    2018-01-01

    experiments at the best working conditions (dry and in absence of SO2) are performed to characterize the intrinsic catalytic behavior of the new catalysts. At temeprature lower than 300 °C, superior NOx conversion properties of the amorphous TiOx nanofibers over the crystallized TiO2 (anatase) nanofibers......Herein for the first time, Ce0.184W0.07Ti0.748O2-δ nanofibers are prepared by electrospinning to serve as catalyst in the selective catalytic reduction (SCR) process. The addition of cerium is proven to inhibit crystallization of TiO2, yielding an amorphous TiOx-based solid solution stable up...... temperatures (catalysts in a wide range...

  3. Characterization of composite metal-ceramic of nickel-oxide cerium doped gadolinium; Caracterizacao de compositos ceramica-metal de niquel e oxido de cerio dopado com gadolinio

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.L.A. da, E-mail: maria.andrade@pro.unifacs.br [Universidade Salvador (UNIFACS), BA (Brazil). Escola de Engenharia, Arquitetura e TI; Universidade Federal da Bahia (UFBA), BA (Brazil); Varela, M.C.R.S. [Universidade Federal da Bahia (UFBA), BA (Brazil)

    2016-07-01

    Composite nickel doped cerium oxide are used in SOFC anode materials. In this study we evaluated the effect of the presence of gadolinium on the properties of composite nickel and ceria and. The supports were synthesized by sol-gel method. The impregnation with nickel nitrate was taken sequentially, followed by calcination. The materials were characterized by X-ray diffraction, measurement of specific surface area, temperature programmed reduction, Raman spectroscopy. The presence of gadolinium retained the fluorite structure of ceria by forming a solid solution, also not influencing significantly on the specific surface area of the support. On the other hand, there was a decrease in the area catalysts, which can be attributed to sintering of nickel. Furthermore, addition of gadolinium favored the formation of intrinsic and extrinsic vacancies in cerium oxide, which leads to an increase in the ionic conductivity of the solid, desirable property for an SOFC anode catalyst. (author)

  4. Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids - Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method

    International Nuclear Information System (INIS)

    2004-01-01

    This first edition of ISO 7097-1 together with ISO 7097-2:2004 cancels and replaces ISO 7097:1983, which has been technically revised, and ISO 9989:1996. ISO 7097 consists of the following parts, under the general title Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids: Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method; Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method. This part 2. of ISO 7097 describes procedures for determination of uranium in solutions, uranium hexafluoride and solids. The procedures described in the two independent parts of this International Standard are similar: this part uses a titration with cerium(IV) and ISO 7097-1 uses a titration with potassium dichromate

  5. Alumina supported Co-K-Mo based catalytic material for diesel soot oxidation

    Czech Academy of Sciences Publication Activity Database

    Dhakad, M.; Joshi, A.G.; Rayalu, S.; Tanwar, P.; Bassin, J.K.; Kumar, R.; Lokhande, S.; Šubrt, Jan; Mitsuhashi, T.; Labhsetwar, N.

    2009-01-01

    Roč. 52, 13-20 (2009), s. 2070-2075 ISSN 1022-5528 Institutional research plan: CEZ:AV0Z40320502 Keywords : soot oxidation * diesel particulate filter * catalyst carbon oxidation Subject RIV: CA - Inorganic Chemistry Impact factor: 2.379, year: 2009

  6. Nanocasted synthesis of magnetic mesoporous iron cerium bimetal oxides (MMIC) as an efficient heterogeneous Fenton-like catalyst for oxidation of arsenite.

    Science.gov (United States)

    Wen, Zhipan; Zhang, Yalei; Dai, Chaomeng; Sun, Zhen

    2015-04-28

    Magnetic mesoporous iron cerium bimetal oxides (MMIC) with large surface area and pore volume was synthesized via the hard template approach. This obtained MMIC was easily separated from aqueous solution with an external magnetic field and was proposed as a heterogeneous Fenton-like catalyst for oxidation of As(III). The MMIC presented excellent catalytic activity for the oxidation of As(III), achieving almost complete oxidation of 1000ppb As(III) after 60min and complete removal of arsenic species after 180min with reaction conditions of 0.4g/L catalyst, pH of 3.0 and 0.4mM H2O2. Kinetics analysis showed that arsenic removal followed the pseudo-first order, and the pseudo-first-order rate constants increased from 0.0014min(-1) to 0.0548min(-1) as the H2O2 concentration increased from 0.04mM to 0.4mM. On the basis of the effects of XPS analysis and reactive oxidizing species, As(III) in aqueous solution was mainly oxidized by OH radicals, including the surface-bound OHads generated on the MMIC surface which were involved in Fe(2+) and Ce(3+), and free OHfree generation by soluble iron ions which were released from the MMIC into the bulk solution, and the generated As(V) was finally removed by MMIC through adsorption. Copyright © 2015 Elsevier B.V. All rights reserved.

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

  8. Catalytic oxidative desulfurization of diesel utilizing hydrogen peroxide and functionalized-activated carbon in a biphasic diesel-acetonitrile system

    Energy Technology Data Exchange (ETDEWEB)

    Haw, Kok-Giap; Bakar, Wan Azelee Wan Abu; Ali, Rusmidah; Chong, Jiunn-Fat [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia); Kadir, Abdul Aziz Abdul [Department of Petroleum Engineering, Faculty of Chemical and Natural Resources Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

    2010-09-15

    This paper presents the development of granular functionalized-activated carbon as catalysts in the catalytic oxidative desulfurization (Cat-ODS) of commercial Malaysian diesel using hydrogen peroxide as oxidant. Granular functionalized-activated carbon was prepared from oil palm shell using phosphoric acid activation method and carbonized at 500 C and 700 C for 1 h. The activated carbons were characterized using various analytical techniques to study the chemistry underlying the preparation and calcination treatment. Nitrogen adsorption/desorption isotherms exhibited the characteristic of microporous structure with some contribution of mesopore property. The Fourier Transform Infrared Spectroscopy results showed that higher activation temperature leads to fewer surface functional groups due to thermal decomposition. Micrograph from Field Emission Scanning Electron Microscope showed that activation at 700 C creates orderly and well developed pores. Furthermore, X-ray Diffraction patterns revealed that pyrolysis has converted crystalline cellulose structure of oil palm shell to amorphous carbon structure. The influence of the reaction temperature, the oxidation duration, the solvent, and the oxidant/sulfur molar ratio were examined. The rates of the catalytic oxidative desulfurization reaction were found to increase with the temperature, and H{sub 2}O{sub 2}/S molar ratio. Under the best operating condition for the catalytic oxidative desulfurization: temperature 50 C, atmospheric pressure, 0.5 g activated carbon, 3 mol ratio of hydrogen peroxide to sulfur, 2 mol ratio of acetic acid to sulfur, 3 oxidation cycles with 1 h for each cycle using acetonitrile as extraction solvent, the sulfur content in diesel was reduced from 2189 ppm to 190 ppm with 91.3% of total sulfur removed. (author)

  9. Study of cyclic oxidation for stainless steels AISI 309 T 253 M A, with low additions of cerium; Estudio de la oxidacion ciclica de los aceros inoxidables AISI 309 T 253 MA, con pequenas adiciones de Cerio

    Energy Technology Data Exchange (ETDEWEB)

    Velazquez F, G.L.; Martinez, M.; Ruiz, A. [Universidad Nacional Experimental Politecnica (UNEXPO) - Vicerrectorado de Puerto Ordaz, Centro de Estudios de Corrosion. Puerto Ordaz. venezuela (Venezuela)

    1998-12-31

    It has been detected that the addition of small amounts (<1%) of the so called `reactive elements` such as Cerium to Fe-Cr alloys that was utilized in oxidating environment at high temperatures improving its resistance to oxidation under isothermal and cyclic conditions. In this work, it was evaluated the behavior under cyclic oxidation conditions for an austenitic stainless steel at chromium-nickel (253MA) with cerium addition, and comparing it with the AISI 310S austenitic stainless steel. The cyclic oxidation essays consist of five cycles by 24 hours each one, following of a cooling in air until ambient temperature from the temperatures of 850, 900 and 950 Centigrade, registering the gain mass of the specimen at end of each cycle. In order to this were prepared samples with dimensions of 20 mm. x 10 mm. x 1 mm. Later to the oxidation essays was evaluated the morphology of the corrosion products layer by scanning electron microscopy. The present phases were identified by X-ray diffraction and by chemical microanalysis by Dispersive energy (EDAX). The results obtained show that the steel with cerium addition, presents a higher adherence and resistance to the spalling noting that the cerium promotes the casting anchor of the oxides layer to matrix and by reducing the grain size of the layer improving its plasticity. Additionally the cerium promotes the preferential oxidation of the forming elements of protective layers like the chromium. (Author)

  10. Biodegradation and corrosion behavior of manganese oxidizer Bacillus cereus ACE4 in diesel transporting pipeline

    International Nuclear Information System (INIS)

    Rajasekar, A.; Ganesh Babu, T.; Karutha Pandian, S.; Maruthamuthu, S.; Palaniswamy, N.; Rajendran, A.

    2007-01-01

    The degradation problem of petroleum products arises since hydrocarbon acts as an excellent food source for a wide variety of microorganisms. Microbial activity leads to unacceptable level of turbidity, corrosion of pipeline and souring of stored product. The present study emphasizes the role of Bacillus cereus ACE4 on degradation of diesel and its influence on corrosion of API 5LX steel. A demonstrating bacterial strain ACE4 was isolated from corrosion products and 16S rRNA gene sequence analysis showed that it has more than 99% similarity with B. cereus. The biodegradation and corrosion studies revealed that B. cereus degraded the aliphatic protons and aromatic protons in diesel and is capable of oxidizing ferrous/manganese into oxides. This is the first report that discloses the involvement of manganese oxidizer B. cereus ACE4 on biodegradation of diesel and its influence on corrosion in a tropical country pipeline

  11. 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.

  12. Modulation of surface structure and catalytic properties of cerium oxide nanoparticles by thermal and microwave synthesis techniques

    Energy Technology Data Exchange (ETDEWEB)

    He, Jian [College of Pharmacy, Third Military Medical University, Chongqing 400038 (China); Zhou, Lan; Liu, Jie; Yang, Lu; Zou, Ling; Xiang, Junyu; Dong, Shiwu [School of Biomedical Engineering, Third Military Medical University, Chongqing 400038 (China); Yang, Xiaochao, E-mail: xcyang@tmmu.edu.cn [School of Biomedical Engineering, Third Military Medical University, Chongqing 400038 (China)

    2017-04-30

    Highlights: • The CNPs synthesized by microwave irradiation have more reactive hot spots than that synthesized by convective heating. • The CNPs synthesized by microwave irradiation exhibited higher SOD activity than that synthesized by convective heating. • The CNPs synthesized by microwave irradiation heating could better protect cells from oxidative stress. - Abstract: Cerium oxide nanoparticles (CNPs) have been intensively explored for biomedical applications in recent few years due to the versatile enzyme mimetic activities of the nanoparticles. However, the control of CNPs quality through the optimization of synthesis conditions remains largely unexplored as most of the previous studies only focus on utilizing the catalytic activities of the nanoparticles. In the present study, CNPs with size about 5 nm were synthesized by thermal decomposition method using traditional convective heating and recently developed microwave irradiation as heating source. The quality of CNPs synthesized by the two heating manner was evaluated. The CNPs synthesized by convective heating were slightly smaller than that synthesized by microwave irradiation heating. The cores of the CNPs synthesized by the two heating manner have similar crystal structure. While the surface subtle structures of the CNPs synthesized by two heating manner were different. The CNPs synthesized by microwave irradiation have more surface reactive hot spot than that synthesized by convective heating as the nanoparticles responded more actively to the redox environment variation. This difference resulted in the higher superoxide dismutase (SOD) mimetic activity of CNPs synthesized by microwave irradiation heating than that of the convective heating. Preliminary experiments indicated that the CNPs synthesized by microwave irradiation heating could better protect cells from oxidative stress due to the higher SOD mimetic activity of the nanoparticles.

  13. Modulation of surface structure and catalytic properties of cerium oxide nanoparticles by thermal and microwave synthesis techniques

    International Nuclear Information System (INIS)

    He, Jian; Zhou, Lan; Liu, Jie; Yang, Lu; Zou, Ling; Xiang, Junyu; Dong, Shiwu; Yang, Xiaochao

    2017-01-01

    Highlights: • The CNPs synthesized by microwave irradiation have more reactive hot spots than that synthesized by convective heating. • The CNPs synthesized by microwave irradiation exhibited higher SOD activity than that synthesized by convective heating. • The CNPs synthesized by microwave irradiation heating could better protect cells from oxidative stress. - Abstract: Cerium oxide nanoparticles (CNPs) have been intensively explored for biomedical applications in recent few years due to the versatile enzyme mimetic activities of the nanoparticles. However, the control of CNPs quality through the optimization of synthesis conditions remains largely unexplored as most of the previous studies only focus on utilizing the catalytic activities of the nanoparticles. In the present study, CNPs with size about 5 nm were synthesized by thermal decomposition method using traditional convective heating and recently developed microwave irradiation as heating source. The quality of CNPs synthesized by the two heating manner was evaluated. The CNPs synthesized by convective heating were slightly smaller than that synthesized by microwave irradiation heating. The cores of the CNPs synthesized by the two heating manner have similar crystal structure. While the surface subtle structures of the CNPs synthesized by two heating manner were different. The CNPs synthesized by microwave irradiation have more surface reactive hot spot than that synthesized by convective heating as the nanoparticles responded more actively to the redox environment variation. This difference resulted in the higher superoxide dismutase (SOD) mimetic activity of CNPs synthesized by microwave irradiation heating than that of the convective heating. Preliminary experiments indicated that the CNPs synthesized by microwave irradiation heating could better protect cells from oxidative stress due to the higher SOD mimetic activity of the nanoparticles.

  14. Effect of cerium doping on the electrical properties of ultrathin indium tin oxide films for application in touch sensors

    International Nuclear Information System (INIS)

    Kang, Saewon; Cho, Sanghyun; Song, Pungkeun

    2014-01-01

    The electrical and microstructure properties of cerium doped indium tin oxide (ITO:Ce) ultrathin films were evaluated to assess their potential application in touch sensors. 10 to 150-nm ITO and ITO:Ce films were deposited on glass substrates (200 °C) by DC magnetron sputtering using different ITO targets (doped with CeO 2 : 0, 1, 3, 5 wt.%). ITO:Ce (doped with CeO 2 : 3 wt.%) films with thickness < 25 nm showed lower resistivity than ITO. This lower resistivity was accompanied by a significant increase in the Hall mobility despite a decrease in crystallinity. In addition, the surface morphology and wetting properties improved with increasing Ce concentration. This is related to an earlier transition from an island structure to continuous film formation caused by an increase in the initial nucleation density. - Highlights: • 10 to 150-nm InSnO 2 (ITO) and ITO:Ce thin films were deposited by sputtering. • ITO:Ce films with thickness < 25 nm showed lower resistivity than ITO. • Hall mobility was strongly affected by initial film formation. • Surface morphology and wetting property improved with increasing Ce concentration. • Such behavior is related to an earlier transition to continuous film formation

  15. Nucleation front instability in two-dimensional (2D) nanosheet gadolinium-doped cerium oxide (CGO) formation

    DEFF Research Database (Denmark)

    Marani, Debora; Moraes, Leticia Poras Reis; Gualandris, Fabrizio

    2018-01-01

    Herein we report for the first time the synthesis of ceramic–organic three-dimensional (3D) layered gadolinium-doped cerium oxide (Ce1−XGdXO2−δ, CGO) and its exfoliation into two-dimensional (2D) nanosheets. We adopt a water-based synthetic route via a homogenous precipitation approach at low...... temperatures (10–80 °C). The reaction conditions are tuned to investigate the effects of thermal energy on the final morphology. A low temperature (40 °C) morphological transition from nanoparticles (1D) to two-dimensional (2D) nanosheets is observed and associated with a low thermal energy transition of ca. 2.......6 kJ mol−1. For the 3D-layered material, exfoliation experiments are conducted in water/ethanol solutions. Systems at volume fractions ranging from 0.15 to 0.35 are demonstrated to promote under ultrasonic treatment the delamination into 2D nanosheets....

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

    International Nuclear Information System (INIS)

    Li, Jia; Zhang, Quan; Lai, Alvin C.K.; Zeng, Liping

    2016-01-01

    In order to degrade in-car formaldehyde gas, graphene oxide (GO), cerium (Ce), and TiO_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_2 composite film by way of immersion, coating, and calcinations. The morphology and crystal structure of as-prepared Ce-GO-TiO_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_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)

  17. Continuous precipitation of mineral products: influence of mixing conditions on the co-precipitation of cerium-zirconium mixed oxides

    International Nuclear Information System (INIS)

    Di Patrizio, Nicolas

    2015-01-01

    An automated experimental set-up with rapid mixers is used to study the influence of mixing conditions on the co-precipitation of cerium-zirconium mixed oxides. The intensity of mixing is controlled by the inlet flow rates of the reacting solutions. An engulfment model is used to estimate a mixing time from the measurement of a segregation index by the Villermaux-Dushman reaction system. Three geometries of Hartridge Roughton mixers are compared. Mixing performance is better when a separate mixing chamber upstream of a narrower outlet pipe is present. A better mixing decreases the maximal reducibility temperature of the material and increases the crystal strains of the particles calcined at 1100 C. This is probably due to a better homogenization of the particles content. The important incorporation of nitrates in the particle at the outlet of the mixers shows precipitation occurs while the mixing process is not finished. This experimental result was confirmed by numerical simulation and an estimation of sur-saturations during the mixing process. (author)

  18. 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%.

  19. Incorporation of cerium oxide into hydroxyapatite coating regulates osteogenic activity of mesenchymal stem cell and macrophage polarization.

    Science.gov (United States)

    Li, Kai; Shen, Qingyi; Xie, Youtao; You, Mingyu; Huang, Liping; Zheng, Xuebin

    2017-02-01

    Biomedical coatings for orthopedic implants should facilitate osseointegration and mitigate implant-induced inflammatory reactions. Cerium oxide (CeO 2 ) ceramics possess anti-oxidative properties and can be used to decrease mediators of inflammation, which makes them attractive for biomedical applications. In our work, two kinds of CeO 2 incorporated hydroxyapatite coatings (HA-10Ce and HA-30Ce) were prepared via plasma spraying technique and the effects of CeO 2 addition on the responses of bone mesenchymal stem cells (BMSCs) and RAW264.7 macrophages were investigated. An increase in CeO 2 content in the HA coatings resulted in better osteogenic behaviors of BMSCs in terms of cell proliferation, alkaline phosphatase (ALP) activity and mineralized nodule formation. RT-PCR and western blot analysis suggested that the incorporation of CeO 2 may promote the osteogenic differentiation of BMSCs through the Smad-dependent BMP signaling pathway, which activated Runx2 expression and subsequently enhanced the expression of ALP and OCN. The expression profiles of macrophages cultured on the CeO 2 modified coating revealed a tendency toward a M2 phenotype, because of an upregulation of M2 surface markers (CD163 and CD206), anti-inflammatory cytokines (TNF-α and IL-6) and osteoblastogenesis-related genes (BMP2 and TGF-β1) as well as a downregulation of M1 surface markers (CCR7 and CD11c), proinflammatory cytokines (IL-10 and IL-1ra) and reactive oxygen species production. The results suggested the regulation of BMSCs behaviors and macrophage-mediated responses at the coating's surface were associated with CeO 2 incorporation. The incorporation of CeO 2 in HA coatings can be a valuable strategy to promote osteogenic responses and reduce inflammatory reactions.

  20. 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.

  1. In-vehicle measurement of ultrafine particles on compressed natural gas, conventional diesel, and oxidation-catalyst diesel heavy-duty transit buses.

    Science.gov (United States)

    Hammond, Davyda; Jones, Steven; Lalor, Melinda

    2007-02-01

    Many metropolitan transit authorities are considering upgrading transit bus fleets to decrease ambient criteria pollutant levels. Advancements in engine and fuel technology have lead to a generation of lower-emission buses in a variety of fuel types. Dynamometer tests show substantial reductions in particulate mass emissions for younger buses (vehicle particle number concentration measurements on conventional diesel, oxidation-catalyst diesel and compressed natural gas transit buses are compared to estimate relative in-vehicle particulate exposures. Two primary consistencies are observed from the data: the CNG buses have average particle count concentrations near the average concentrations for the oxidation-catalyst diesel buses, and the conventional diesel buses have average particle count concentrations approximately three to four times greater than the CNG buses. Particle number concentrations are also noticeably affected by bus idling behavior and ventilation options, such as, window position and air conditioning.

  2. Interactions of NO{sub 2} at ambient temperature with cerium-zirconium mixed oxides supported on SBA-15

    Energy Technology Data Exchange (ETDEWEB)

    Levasseur, Benoit; Ebrahim, Amani M. [The City College of New York and The Graduate School of CUNY 160 Convent Ave, New York, NY 10031 (United States); Burress, Jacob [NIST Center for Neutron Research, National Institute of Standards and Technology 100 Bureau Drive, Gaithersburg, MD 20899 (United States); Bandosz, Teresa J., E-mail: tbandosz@ccny.cuny.edu [The City College of New York and The Graduate School of CUNY 160 Convent Ave, New York, NY 10031 (United States)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Ce{sub 1-y}Zr{sub y}O{sub 2-x} mixed oxides were highly dispersed in mesoporous silica SBA-15. Black-Right-Pointing-Pointer A strong increase in the NO{sub 2} adsorption capacity was observed on composites. Black-Right-Pointing-Pointer The insertion of Zr{sup 4+} in ceria fluorite structure promotes the reduction of Ce{sup 4+} into Ce{sup 3+}. Black-Right-Pointing-Pointer Ce{sup 3+} and -OH groups were found to be the main active centers for NO{sub x} retention. Black-Right-Pointing-Pointer The structure remains quite stable after exposure to NO{sub 2} in ambient conditions. - Abstract: New silica-based composites were obtained using a slow precipitation of mixed oxide Ce{sub 1-x}Zr{sub x}O{sub 2} on the surface of mesoporous silica, SBA-15. The samples were tested as NO{sub 2} adsorbents in dynamic conditions at room temperature. The surface of the initial and exhausted materials was characterized using N{sub 2} sorption, XRD, TEM, potentiometric titration, and thermal analysis before and after exposure to NO{sub 2}. In comparison with unsupported Ce{sub 1-x}Zr{sub x}O{sub 2} mixed oxides, a significant increase in the NO{sub 2} adsorption capacity was observed. This is due to the high dispersion of active oxide phase on the surface of SBA-15. A linear trend was found between the NO{sub 2} adsorption capacity and the amount of Zr(OH){sub 4} added to the structure. Introduction of Zr{sup 4+} cations to ceria contributes to an increase in the amount of Ce{sup 3+}, which is the active center for the NO{sub 2} adsorption, and to an increase in the density of -OH groups. These groups are found to be involved in the retention of both NO{sub 2} and NO on the surface. After exposure to NO{sub 2}, an acidification of the surface caused by the oxidation of the cerium as well as the formation of nitrite and nitrates took place. The structure of the composites appears not to be affected by reactive adsorption of NO{sub 2}.

  3. 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)

  4. 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

  5. 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.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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 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, 18 O 2 isotopic exchange and O 2 -H 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.

  7. The effects of gamma irradiation on the elastic properties of soda lime glass doped with cerium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Laopaiboon, R.; Laopaiboon, J.; Pencharee, S. [Glass Technology Excellent Center (GTEC), Department of Physics, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190 (Thailand); Nontachat, S. [Department of Radiotherapy, Ubon Ratchathani Cancer Centre, Ubon Ratchathani, 34190 (Thailand); Bootjomchai, C., E-mail: cherdsak_per@hotmail.co.th [Glass Technology Excellent Center (GTEC), Department of Physics, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190 (Thailand)

    2016-05-05

    Soda lime glass doped with cerium oxide was prepared using a conventional melt quenching technique. The density and molar volume of the glass samples were measured. Ultrasonic wave velocities of the glass samples were carried out using a pulse echo technique. The density and ultrasonic velocities were used for determining elastic moduli of the glass samples, both before and after irradiation with gamma rays at 1 kGy. The results revealed that the influence of gamma irradiation caused the matrix structure of the glass samples to be damaged by creating displacements, electronic defects and/or breaks in the network bonds, leading to the formation of non-bridging oxygens (NBOs). Elastic properties were investigated under the influence of gamma irradiation. The results also revealed that the structures of the glass samples were distorted by irradiation. Damage by irradiation created the NBOs and/or the transformation of main glass network structures from Q{sub 4} to Q{sub 3}. Evidence of these results was acquired from FTIR spectra. The results of FTIR supported the results and were obtained from ultrasonic velocities. In addition, the elastic properties obtained from experiments were compared with theoretical values calculated from the Makishima and Mackenzie model (M–M model). - Highlights: • Results show good agreement between experimental and theoretical of elastic moduli. • Influence of irradiation created a distorted network structure. • Transformation of network structure from Ref. Q{sub 4} to Q{sub 3} after irradiation. • FTIR result is good evidence of the result is obtained from ultrasonic technique.

  8. Storage and characterization of the hydrogen in mixed oxides on base of cerium-nickel and zirconium or the aluminium

    International Nuclear Information System (INIS)

    Debeusscher, S.

    2008-12-01

    The mixed oxides based on cerium-nickel and zirconium or aluminium are able to store large quantities of hydrogen, To determine nature, reactivity and properties of hydrogen species (spill-over, direct desorption), the solid were studied by different physicochemical techniques in the dried, calcined and partially reduced states: XRD, porosity, TGA, TPR, TPA, TPD, chemical titration and inelastic neutron scattering (INS). Solids are mainly meso-porous with a common pore size at 4 nm, They are constituted of CeO 2 phase, Ce-Ni or Ce-Ni-Zr solid solution and of Ni(OH) 2 in the dried state and NiO in the calcined state. The Ni species are in various environments and the strong interactions between the cations in solid solution and at different particles interface influence their reducibility and the creation of anionic vacancies. Activation in H 2 in temperature is determining for hydrogen storage in the solid while calcination step is not necessary. INS Analyses evidence that the hydrogen species inserted during treatment in H 2 are H + (OH - ), hydride H - and H * (metallic nickel) species, present in various chemical environments, in particular for hydride species. All kinds of hydrogen species participate to the reaction during the chemical titration in agreement with the proposed hydrogenation mechanism. The study of the adsorption of hydrogen shows that this step is fast and in quantity of the same order as that measured by chemical titration. The direct desorption of H 2 is very low, linked to the presence of hydrogen in interaction with metallic nickel (H *- .). Desorption of water is also observed, in parallel, corresponding to the elimination of groups. The hydride species are not desorbed. These various observations allow connecting hydrogen species properties with their localization in the structure and to model active sites. (author)

  9. Cerium oxide nanoparticles alter the salt stress tolerance of Brassica napus L. by modifying the formation of root apoplastic barriers.

    Science.gov (United States)

    Rossi, Lorenzo; Zhang, Weilan; Ma, Xingmao

    2017-10-01

    Rapidly growing global population adds significant strains on the fresh water resources. Consequently, saline water is increasingly tapped for crop irrigation. Meanwhile, rapid advancement of nanotechnology is introducing more and more engineered nanoparticles into the environment and in agricultural soils. While some negative effects of ENPs on plant health at very high concentrations have been reported, more beneficial effects of ENPs at relatively low concentrations are increasingly noticed, opening doors for potential applications of nanotechnology in agriculture. In particular, we found that cerium oxide nanoparticles (CeO 2 NPs) improved plant photosynthesis in salt stressed plants. Due to the close connections between salt stress tolerance and the root anatomical structures, we postulated that CeO 2 NPs could modify plant root anatomy and improve plant salt stress tolerance. This study aimed at testing the hypothesis with Brassica napus in the presence of CeO 2 NPs (0, 500 mg kg -1 dry sand) and/or NaCl (0, 50 mM) in a growth chamber. Free hand sections of fresh roots were taken every seven days for three weeks and the suberin lamellae development was examined under a fluorescence microscope. The results confirmed the hypothesis that CeO 2 NPs modified the formation of the apoplastic barriers in Brassica roots. In salt stressed plants, CeO 2 NPs shortened the root apoplastic barriers which allowed more Na + transport to shoots and less accumulation of Na + in plant roots. The altered Na + fluxes and transport led to better physiological performance of Brassica and may lead to new applications of nanotechnology in agriculture. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Evaluation of in vitro cytotoxicity, biocompatibility, and changes in the expression of apoptosis regulatory proteins induced by cerium oxide nanocrystals

    Science.gov (United States)

    Khan, Shahanavaj; Ansari, Anees A.; Rolfo, Christian; Coelho, Andreia; Abdulla, Maha; Al-Khayal, Khayal; Ahmad, Rehan

    2017-12-01

    Cerium oxide nanocrystals (CeO2-NCs) exhibit superoxide dismutase and catalase mimetic activities. Based on these catalytic activities, CeO2-NCs have been suggested to have the potential to treat various diseases. The crystalline size of these materials is an important factor that influences the performance of CeO2-NCs. Previous reports have shown that several metal-based nanocrystals, including CeO2-NCs, can induce cytotoxicity in cancer cells. However, the underlying mechanisms have remained unclear. To characterize the anticancer activities of CeO2-NCs, several assays related to the mechanism of cytotoxicity and induction of apoptosis has been performed. Here, we have carried out a systematic study to characterize CeO2-NCs phase purity (X-ray diffraction), morphology (electron microscopy), and optical features (optical absorption, Raman scattering, and photoluminescence) to better establish their potential as anticancer drugs. Our study revealed anticancer effects of CeO2-NCs in HT29 and SW620 colorectal cancer cell lines with half-maximal inhibitory concentration (IC50) values of 2.26 and 121.18 μg ml-1, respectively. Reductions in cell viability indicated the cytotoxic potential of CeO2-NCs in HT29 cells based on inverted and florescence microscopy assessments. The mechanism of cytotoxicity confirmed by estimating possible changes in the expression levels of Bcl2, BclxL, Bax, PARP, cytochrome c, and β-actin (control) proteins in HT29 cells. Down-regulation of Bcl2 and BclxL and up-regulation of Bax, PARP, and cytochrome c proteins suggested the significant involvement of CeO2-NCs exposure in the induction of apoptosis. Furthermore, biocompatibility assay showed minimum effect of CeO2-NCs on human red blood cells.

  11. Particle-specific toxicity and bioavailability of cerium oxide (CeO{sub 2}) nanoparticles to Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xinping; Pan, Haopeng [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Wang, Peng, E-mail: p.wang3@uq.edu.au [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); The University of Queensland, School of Agriculture and Food Sciences, St. Lucia, Queensland 4072 (Australia); Zhao, Fang-Jie [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom)

    2017-01-15

    Highlights: • The phytotoxicity and uptake of CeO{sub 2} NPs were examined in Arabidopsis. • CeO{sub 2} NPs stimulated plant growth at low doses but were toxic at high doses. • The toxicity was due to the NPs per se, rather than from the dissolved Ce ions. • A similar up-translocation factor was found for CeO{sub 2} NPs, bulk CeO{sub 2} and Ce ions. - Abstract: The use of manufactured cerium oxide nanoparticles (CeO{sub 2}-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 CeO{sub 2}-NPs in Arabidopsis thaliana grown in an agar medium. Although low concentrations of CeO{sub 2}-NPs had stimulatory effects on plant growth, at higher concentrations, CeO{sub 2}-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. CeO{sub 2}-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. CeO{sub 2}-NPs, CeO{sub 2}-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 CeO{sub 2}-NPs in plants, which needs to be considered in environmental risk assessment for the safe use and disposal of CeO{sub 2}-NPs.

  12. Effects of Alumina Nano Metal Oxide Blended Palm Stearin Methyl Ester Bio-Diesel on Direct Injection Diesel Engine Performance and Emissions

    Science.gov (United States)

    Krishna, K.; Kumar, B. Sudheer Prem; Reddy, K. Vijaya Kumar; Charan Kumar, S.; Kumar, K. Ravi

    2017-08-01

    The Present Investigation was carried out to study the effect of Alumina Metal Oxide (Al2O3) Nano Particles as additive for Palm Stearin Methyl Ester Biodiesel (B 100) and their blends as an alternate fuel in four stroke single cylinder water cooled, direct injection diesel engine. Alumina Nano Particles has high calorific value and relatively high thermal conductivity (30-1 W m K-1) compare to diesel, which helps to promote more combustion in engines due to their higher thermal efficiency. In the experimentation Al2O3 were doped in various proportions with the Palm Stearin Methyl Ester Biodiesel (B-100) using an ultrasonicator and a homogenizer with cetyl trimethyl ammonium bromide (CTAB) as the cationic surfactant. The test were performed on a Kirsloskar DI diesel engine at constant speed of 1500 rpm using different Nano Biodiesel Fuel blends (psme+50 ppm, psme+150 ppm, and psme+200 ppm) and results were compared with those of neat conventional diesel and Palm Stearin Methyl Ester Bio diesel. It was observed that for Nano Biodiesel Fuel blend (psme+50ppm) there is an significant reduction in carbon monoxide (CO) emissions and Nox emissions compared to diesel and the brake thermal efficiency for (psme+50ppm) was almost same as diesel.

  13. The possible role of cerium oxide (CeO 2 ) nanoparticles in ...

    African Journals Online (AJOL)

    Results showed that CeO2NPs resulted in partial neuroprotection against disturbances in motor performance. It also partially decreased apoptosis and oxidative stress in preventive group, while it failed to increase striatal dopamine level as compared to untreated rats. The present study verified some neuroprotective effects ...

  14. 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...

  15. Comparison of Titration ICP and XRF Spectrometry Methods in Determination of Cerium in Lens Polishing Powder

    International Nuclear Information System (INIS)

    Ninlaphruk, Sumalee; Pichestapong, Pipat; Mungpayabal, Harinate; Jiyavaranant, Thitima; Srisukho, Supapan; Chaisai, Prapassurn

    2004-10-01

    Three analytical methods in determination of cerium in cerium oxide separated from monazite ore for producing lens polishing powder were compared. These methods are titration ICP and XRF spectrometry techniques. The cerium oxide sample with estimated 45% cerium content needed to be digested and converted into solution before the analysis. The analytical results shown significantly no difference between each method. However, the titration method was found to be more convenient and suitable for quality control in the production of cerium oxide as it does not require standard cerium and the complicated analytical instruments

  16. Preparation of high-purity cerium nitrate; Preparacao de nitrato de cerio de alta pureza

    Energy Technology Data Exchange (ETDEWEB)

    Avila, Daniela Moraes; Silva Queiroz, Carlos Alberto da; Santos Mucillo, Eliana Navarro dos [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1995-12-31

    The preparation of high-purity cerium nitrate has been carried out Cerium oxide has been prepared by fractioned precipitation and ionic exchange techniques, using a concentrate with approximately 85% of cerium oxide from NUCLEMON as raw material. Five sequential ion-exchange columns with a retention capacity of 170 g each have been used. The ethylenediamine-tetraacetic acid (EDTA) was used as eluent. The cerium content has been determined by gravimetry and iodometry techniques. The resulting cerium oxide has a purity > 99%. This material was transformed in cerium nitrate to be used as precursor for the preparation of Zirconia-ceria ceramics by the coprecipitation technique. (author) 2 tabs.

  17. Effects of nano metal oxide blended Mahua biodiesel on CRDI diesel engine

    Directory of Open Access Journals (Sweden)

    C. Syed Aalam

    2017-12-01

    Full Text Available In this paper, aluminium oxide nanoparticles (ANPs were added to Mahua biodiesel blend (MME20 in different proportions to investigate the effects on a four stroke, single cylinder, common rail direct injection (CRDI diesel engine. The ANPs were doped in different proportions with the Mahua biodiesel blend (MME20 using an ultrasonicator and a homogenizer with cetyl trimethyl ammonium bromide (CTAB as the cationic surfactant. The experiments were conducted in a CRDI diesel engine at a constant speed of 1500 rpm using different ANP-blended biodiesel fuel (MME20 + ANP50 and MME20 + ANP100 and the results were compared with those of neat diesel and Mahua biodiesel blend (MME20. The experimental results exposed a substantial enhancement in the brake thermal efficiency and a marginal reduction in the harmful pollutants (such as CO, HC and smoke for the nanoparticles blended biodiesel.

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

    International Nuclear Information System (INIS)

    Leino, Ewelina; Kumar, Narendra; Mäki-Arvela, Päivi; Aho, Atte; Kordás, Krisztián; Leino, Anne-Riikka; Shchukarev, Andrey; Murzin, Dmitry Yu.; Mikkola, Jyri-Pekka

    2013-01-01

    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 2 properties was discussed. Moreover, the comparison of CeO 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 2 . Significant variations in physico-chemical properties of CeO 2 by varying the preparation conditions were observed. Furthermore, the catalytic performances of CeO 2 catalysts were compared in the synthesis of diethyl carbonate starting from ethanol and CO 2 using butylene oxide as a dehydrating agent. The dependence of CeO 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 2

  19. EXAFS and XRD studies of nanocrystalline cerium oxide: the effect of preparation method on the microstructure

    International Nuclear Information System (INIS)

    Savin, S.L.P.; Chadwick, A.V.; Smith, M.E.; O'Dell, L.A.

    2007-01-01

    There is considerable interest in nanocrystalline materials due to their unusual properties, such as enhanced ionic conductivity in the case of nanocrystalline ionic solids. This has potential commercial applications, particularly for oxide ion conductors. However, a detailed knowledge of the microstructure is important in fully understanding the novel properties exhibited by nanocrystalline materials. The final microstructure of a material is dependent on the preparation method used, for example, sol-gel and ball-milling methods are commonly used in the preparation of nanocrystalline oxides. Additionally, there is a problem in maintaining the materials in nanocrystalline form when they are subjected to elevated temperatures. We have been exploring strategies to restrict the growth of nanocrystalline oxides and have found that adding a small amount of an inert material, e.g. SiO 2 or Al 2 O 3 , is particularly effective. We will report XRD and EXAFS studies of nanocrystalline ceria prepared by sol-gel, sol-gel pinned and ball-milling methods and the effect of preparation method on the final microstructure. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Experimental investigation on regulated and unregulated emissions of a diesel/methanol compound combustion engine with and without diesel oxidation catalyst.

    Science.gov (United States)

    Zhang, Z H; Cheung, C S; Chan, T L; Yao, C D

    2010-01-15

    The use of methanol in combination with diesel fuel is an effective measure to reduce particulate matter (PM) and nitrogen oxides (NOx) emissions from in-use diesel vehicles. In this study, a diesel/methanol compound combustion (DMCC) scheme was proposed and a 4-cylinder naturally-aspirated direct-injection diesel engine modified to operate on the proposed combustion scheme. The effect of DMCC and diesel oxidation catalyst (DOC) on the regulated emissions of total hydrocarbons (THC), carbon monoxide (CO), NOx and PM was investigated based on the Japanese 13 Mode test cycle. Certain unregulated emissions, including methane, ethyne, ethene, 1,3-butadiene, BTX (benzene, toluene, xylene), unburned methanol and formaldehyde were also evaluated based on the same test cycle. In addition, the soluble organic fraction (SOF) in the particulate and the particulate number concentration and size distribution were investigated at certain selected modes of operation. The results show that the DMCC scheme can effectively reduce NOx, particulate mass and number concentrations, ethyne, ethene and 1,3-butadiene emissions but significantly increase the emissions of THC, CO, NO(2), BTX, unburned methanol, formaldehyde, and the proportion of SOF in the particles. After the DOC, the emission of THC, CO, NO(2), as well as the unregulated gaseous emissions, can be significantly reduced when the exhaust gas temperature is sufficiently high while the particulate mass concentration is further reduced due to oxidation of the SOF. Copyright 2009 Elsevier B.V. All rights reserved.

  1. Nanocasted synthesis of magnetic mesoporous iron cerium bimetal oxides (MMIC) as an efficient heterogeneous Fenton-like catalyst for oxidation of arsenite

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Zhipan [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Zhang, Yalei, E-mail: zhangyalei@tongji.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Dai, Chaomeng [College of Civil Engineering, Tongji University, Shanghai 200092 (China); Sun, Zhen [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)

    2015-04-28

    Highlights: • MMIC with large surface area and pore volume was synthesized via the hard template. • MMIC could be easily separated from aqueous solution with an external magnetic field. • MMIC presented excellent catalytic activity for the oxidation of As(III). • As(III) was mainly oxidized by surface-bound ·OH{sub ads} and free ·OH{sub free} radicals. • MMIC played a dual function role for the arsenic removal in aqueous solution. - Abstract: Magnetic mesoporous iron cerium bimetal oxides (MMIC) with large surface area and pore volume was synthesized via the hard template approach. This obtained MMIC was easily separated from aqueous solution with an external magnetic field and was proposed as a heterogeneous Fenton-like catalyst for oxidation of As(III). The MMIC presented excellent catalytic activity for the oxidation of As(III), achieving almost complete oxidation of 1000 ppb As(III) after 60 min and complete removal of arsenic species after 180 min with reaction conditions of 0.4 g/L catalyst, pH of 3.0 and 0.4 mM H{sub 2}O{sub 2}. Kinetics analysis showed that arsenic removal followed the pseudo-first order, and the pseudo-first-order rate constants increased from 0.0014 min{sup −1} to 0.0548 min{sup −1} as the H{sub 2}O{sub 2} concentration increased from 0.04 mM to 0.4 mM. On the basis of the effects of XPS analysis and reactive oxidizing species, As(III) in aqueous solution was mainly oxidized by ·OH radicals, including the surface-bound ·OH{sub ads} generated on the MMIC surface which were involved in ≡Fe{sup 2+} and ≡Ce{sup 3+}, and free ·OH{sub free} generation by soluble iron ions which were released from the MMIC into the bulk solution, and the generated As(V) was finally removed by MMIC through adsorption.

  2. Structure and surface morphology studies of cerium oxide system using XRD and SEM analysis

    International Nuclear Information System (INIS)

    Ahmad Jais Alimin; Farid Nasir Ani; Wan Azelee Wan Abu Bakar

    2000-01-01

    Conventional Precious Group Materials (PGM) catalyst systems have been using CeO 2 as an Oxygen Storage Capacity component in the catalyst washcoat. Due to the limitations of the PGM catalyst, researches are now focusing on improving or replacing this conventional system. In a previous work, the potential of a copper-ceria (Cu-Ce) oxide as a catalyst system has been identified. In this paper, the morphology and characterisation of Cu-Ce oxides analysed using XRD and SEM will be described. The Cu-Ce samples were prepared at a fixed ratio under temperatures of 400 o C and 800 o C. XRD diffractograms showed CeO 2 is in a cubic phase at 400 o C and 800 o C. At 800 o C, the CuO particle is visible, presumably has incorporated with the lattice structure of ceria, indicating an absent of solid state condition between copper and ceria. Analysis by SEM revealed significant increase in particle sizes with increasing calcination temperatures. (Author)

  3. Emission characteristics of negative oxygen ions into vacuum from cerium oxide

    International Nuclear Information System (INIS)

    Sakai, Takaaki; Fujiwara, Yukio; Kaimai, Atsushi; Yashiro, Keiji; Matsumoto, Hiroshige; Nigara, Yutaka; Kawada, Tatsuya; Mizusaki, Junichiro

    2006-01-01

    The oxygen ion emission characteristics of CeO 2 were studied under electric field in a vacuum chamber to find a candidate material for a novel ion source, 'solid oxide ion source (SOIS)'. The emission current was observed from CeO 2 under a pressure of around 10 -3 Pa, at the temperature ranging from 973 K to 1173 K. It was found that the emission current increased with temperature and applied voltage. The ions emitted from CeO 2 were confirmed to be oxygen negative ions (O - ) by the use of quadrupole mass spectrometer. The emission current decreased with time as was observed in the earlier works with other oxide ion conductors such as stabilized zirconia or other materials . To enhance the emission current from CeO 2 , an introduction of donor into CeO 2 was tested using Ce 0.992 Nb 0.008 O 2 . For comparison, effect of acceptor doping was also tested using Ce 0.9 Gd 0.1 O 1.95 . The emission current from Ce 0.9 Gd 0.1 O 1.95 was smaller than that from donor-doped and pure CeO 2. Clear enhancement of the emission current was not observed with Ce 0.992 Nb 0.008 O 2

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

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jihoon [WCD Department of Energy Engineering, Hanyang University, Seoul (Korea, Republic of); Moon, Jinok [WCD Department of Energy Engineering, Hanyang University, Seoul (Korea, Republic of); Clean/CMP Technology Team, Memory, Samsung Electronics, Hwaseong (Korea, Republic of); Kim, Joo Hyun; Lee, Kangchun [WCD Department of Energy Engineering, Hanyang University, Seoul (Korea, Republic of); Hwang, Junha [WCD Department of Energy Engineering, Hanyang University, Seoul (Korea, Republic of); Materials R& D Center, K.C.Tech, Anseong (Korea, Republic of); Yoon, Heesung [WCD Department of Energy Engineering, Hanyang University, Seoul (Korea, Republic of); Yi, Dong Kee, E-mail: vitalis@mju.ac.kr [Department of Chemistry, Myongji University, Yongin (Korea, Republic of); Paik, Ungyu, E-mail: upaik@hanyang.ac.kr [WCD Department of Energy Engineering, Hanyang University, Seoul (Korea, Republic of)

    2016-12-15

    Highlights: • We investigated the role of Ce oxidation state (Ce{sup 3+}/Ce{sup 4+}) on the CeO{sub 2} surfaces for the silicate adsorption. • As the Ce{sup 3+} concentration increased from 19.3 to 27.6%, the surface density of −OH group increased from 0.34 to 0.72 OH/nm{sup 2}. • The Freundlich constant for the relative adsorption capacity (K{sub F}) and adsorption intensity (1/n) indicated that CeO{sub 2} NPs with high Ce{sup 3+} concentration show higher adsorption affinity with silicate ions. - Abstract: In this study, we have investigated the role of the Ce oxidation state (Ce{sup 3+}/Ce{sup 4+}) on the CeO{sub 2} surfaces for silicate adsorption. In aqueous medium, the Ce{sup 3+} sites lead to the formation of −OH groups at the CeO{sub 2} surface through H{sub 2}O dissociation. Silicate ions can adsorb onto the CeO{sub 2} surface through interaction with the −OH groups (−Ce−OH− + −Si−O{sup −} ↔ −Ce−O−Si− + OH{sup −}). As the Ce{sup 3+} concentration increased from 19.3 to 27.6%, the surface density of −OH group increased from 0.34 to 0.72 OH/nm{sup 2}. To evaluate the adsorption behaviors of silicate ions onto CeO{sub 2} 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 (K{sub F}) and adsorption intensity (1/n) indicated that CeO{sub 2} NPs with high Ce{sup 3+} concentration show higher adsorption affinity with silicate ions. As a result, we have demonstrated that the Ce oxidation state (Ce{sup 3+}/Ce{sup 4+}) on the CeO{sub 2} surface can have a significant influence on the silicate adsorption.

  5. Model of the thermodynamic properties and structure of the non-stoichiometric plutonium and cerium oxides

    International Nuclear Information System (INIS)

    Manes, L.; Mari, C.; Ray, I.

    1979-01-01

    The tetrahedral defect consisting of one oxygen vacancy bonded to two reduced cations - is an important concept, which, as shown in the present work, can explain both the thermodynamic properties and the structures of the phases of the PuO 2 -x and CeO 2 -x systems. Based on this concept a statistical thermodynamic model has been developed and this model is described along with some preliminary calculations. A relatively good agreement with experimental thermodynamic data was obtained in this calculation. Using the exclusion principle, defect complexes each containing one tetrahedral defect are derived and it is shown that a systematic packing of these gives a good description both of the non-stoichiometric and the ordered phases observed for these oxide systems. (orig.) [de

  6. 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.

  7. Pilot demonstration of cerium oxide coated anodes. Final report, April 1990--October 1992

    Energy Technology Data Exchange (ETDEWEB)

    Gregg, J.S.; Frederick, M.S.; Shingler, M.J.; Alcorn, T.R.

    1992-10-01

    Cu cermet anodes were tested for 213 to 614 hours with an in-situ deposited CEROX coating in a pilot cell operated by Reynolds Manufacturing Technology Laboratory. At high bath ratio ({approximately}1.5) and low current density (0.5 A/cm{sup 2}), a {ge}1 mm thick dense CEROX coating was deposited on the anodes. At lower bath ratios and higher current density, the CEROX coating was thinner and less dense, but no change in corrosion rate was noted. Regions of low current density on the anodes and sides adjacent to the carbon anode sometimes had thin or absent CEROX coatings. Problems with cracking and oxidation of the cermet substrates led to higher corrosion rates in a pilot cell than would be anticipated from lab scale results.

  8. Interactions between sub-10-nm iron and cerium oxide nanoparticles and 3T3 fibroblasts: the role of the coating and aggregation state

    Science.gov (United States)

    Safi, M.; Sarrouj, H.; Sandre, O.; Mignet, N.; Berret, J.-F.

    2010-04-01

    Recent nanotoxicity studies revealed that the physico-chemical characteristics of engineered nanomaterials play an important role in the interactions with living cells. Here, we report on the toxicity and uptake of cerium and iron oxide sub-10-nm nanoparticles by NIH/3T3 mouse fibroblasts. Coating strategies include low-molecular weight ligands (citric acid) and polymers (poly(acrylic acid), MW = 2000 g mol - 1). Electrostatically adsorbed on the surfaces, the organic moieties provide a negatively charged coating in physiological conditions. We find that most particles were biocompatible, as exposed cells remained 100% viable relative to controls. Only the bare and the citrate-coated nanoceria exhibit a slight decrease in mitochondrial activity at very high cerium concentrations (>1 g l - 1). We also observe that the citrate-coated particles are internalized/adsorbed by the cells in large amounts, typically 250 pg/cell after 24 h incubation for iron oxide. In contrast, the polymer-coated particles are taken up at much lower rates (<30 pg/cell). The strong uptake shown by the citrated particles is related to the destabilization of the dispersions in the cell culture medium and their sedimentation down to the cell membranes. In conclusion, we show that the uptake of nanomaterials by living cells depends on the coating of the particles and on its ability to preserve the colloidal nature of the dispersions.

  9. Interactions between sub-10-nm iron and cerium oxide nanoparticles and 3T3 fibroblasts: the role of the coating and aggregation state

    International Nuclear Information System (INIS)

    Safi, M; Sarrouj, H; Berret, J-F; Sandre, O; Mignet, N

    2010-01-01

    Recent nanotoxicity studies revealed that the physico-chemical characteristics of engineered nanomaterials play an important role in the interactions with living cells. Here, we report on the toxicity and uptake of cerium and iron oxide sub-10-nm nanoparticles by NIH/3T3 mouse fibroblasts. Coating strategies include low-molecular weight ligands (citric acid) and polymers (poly(acrylic acid), M W = 2000 g mol -1 ). Electrostatically adsorbed on the surfaces, the organic moieties provide a negatively charged coating in physiological conditions. We find that most particles were biocompatible, as exposed cells remained 100% viable relative to controls. Only the bare and the citrate-coated nanoceria exhibit a slight decrease in mitochondrial activity at very high cerium concentrations (>1 g l -1 ). We also observe that the citrate-coated particles are internalized/adsorbed by the cells in large amounts, typically 250 pg/cell after 24 h incubation for iron oxide. In contrast, the polymer-coated particles are taken up at much lower rates (<30 pg/cell). The strong uptake shown by the citrated particles is related to the destabilization of the dispersions in the cell culture medium and their sedimentation down to the cell membranes. In conclusion, we show that the uptake of nanomaterials by living cells depends on the coating of the particles and on its ability to preserve the colloidal nature of the dispersions.

  10. Interactions between sub-10-nm iron and cerium oxide nanoparticles and 3T3 fibroblasts: the role of the coating and aggregation state

    Energy Technology Data Exchange (ETDEWEB)

    Safi, M; Sarrouj, H; Berret, J-F [Matiere et Systemes Complexes, UMR 7057 CNRS, Universite Denis Diderot Paris VII, Batiment Condorcet, 10 rue Alice Domon et Leonie Duquet, F-75205 Paris (France); Sandre, O [UPMC Universite Paris VI-Laboratoire de Physico-chimie des Electrolytes, Colloides et Sciences Analytiques, UMR 7195 UPMC Universite Paris 6/CNRS/ESPCI Paristech, 4 place Jussieu, F-75252 Paris Cedex 05 (France); Mignet, N, E-mail: jean-francois.berret@univ-paris-diderot.fr [CNRS UMR 8151, Faculte de Pharmacie, 4 avenue de l' Observatoire, F-75270 Paris (France)

    2010-04-09

    Recent nanotoxicity studies revealed that the physico-chemical characteristics of engineered nanomaterials play an important role in the interactions with living cells. Here, we report on the toxicity and uptake of cerium and iron oxide sub-10-nm nanoparticles by NIH/3T3 mouse fibroblasts. Coating strategies include low-molecular weight ligands (citric acid) and polymers (poly(acrylic acid), M{sub W} = 2000 g mol{sup -1}). Electrostatically adsorbed on the surfaces, the organic moieties provide a negatively charged coating in physiological conditions. We find that most particles were biocompatible, as exposed cells remained 100% viable relative to controls. Only the bare and the citrate-coated nanoceria exhibit a slight decrease in mitochondrial activity at very high cerium concentrations (>1 g l{sup -1}). We also observe that the citrate-coated particles are internalized/adsorbed by the cells in large amounts, typically 250 pg/cell after 24 h incubation for iron oxide. In contrast, the polymer-coated particles are taken up at much lower rates (<30 pg/cell). The strong uptake shown by the citrated particles is related to the destabilization of the dispersions in the cell culture medium and their sedimentation down to the cell membranes. In conclusion, we show that the uptake of nanomaterials by living cells depends on the coating of the particles and on its ability to preserve the colloidal nature of the dispersions.

  11. 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.

  12. A recyclable ionic liquid-oxomolybdenum(vi) catalytic system for the oxidative desulfurization of model and real diesel fuel.

    Science.gov (United States)

    Julião, Diana; Gomes, Ana C; Pillinger, Martyn; Valença, Rita; Ribeiro, Jorge C; Gonçalves, Isabel S; Balula, Salete S

    2016-10-14

    The oxidative desulfurization of model and real diesel has been studied using the complex [MoO2Cl2(4,4'-di-tert-butyl-2,2'-bipyridine)] as (pre)catalyst, aq. H2O2 as oxidant, and an ionic liquid as extraction solvent. Under moderate conditions (50 °C) and short reaction times (desulfurization and ECODS steps, 76% sulfur removal was achieved for a real diesel (Sinitial = 2300 ppm). For both the model and real diesels, the catalyst/IL phase could be easily recycled and reused with no loss of desulfurization efficiency.

  13. Oxidative desulfurization of diesel fuel using amphiphilic quaternary ammonium phosphomolybdate catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Jianghua; Wang, Guanghui; Zeng, Danlin; Tang, Yan [College of Chemical Engineering and Technology, Wuhan University of Science and Technology, Wuhan 430081 (China); Wang, Meng; Li, Yanjun [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)

    2009-12-15

    Phosphomolybdic acid (HPMo) modified respectively with tetramethyl ammonium chloride (TMAC), dodecyl trimethyl ammonium chloride (DTAC) and hexadecyl trimethyl ammonium chloride (HTAC) as the catalysts were prepared and characterized by FT-IR, XRD and SEM. The catalysts were evaluated for the oxidative desulfurization of benzothiophene (BT), dibenzothiophene (DBT) and straight-run diesel using hydrogen peroxide as an oxidant. Results show that all of the catalysts keep the Keggin structures and are finely dispersed with mixing of quaternary ammonium salts. Hexadecyl chains are more favorable to wrap up DBT to the catalytic center and form stable emulsion system with higher conversion rates of DBT. The shorter dodecyl chains can wrap up BT more suitably and bring smaller steric hindrance, which display higher conversion rates of BT. The oxidative reactions fit apparent first-order kinetics, and the apparent activation energies of DBT are much lower than those of BT. The desulfurization rate of straight-run diesel can be up to 84.4% with the recovery rate of 98.1% catalyzed by [HPMo][HTAC]{sub 2} in 2 h. When increasing the extraction times, the desulfurization rates increase, but the recovery rates of diesel decrease significantly. (author)

  14. Thermodynamic Aspects of Gasification Derived Syngas Desulfurization, Removal of Hydrogen Halides and Regeneration of Spent Sorbents Based on La2O3/La2O2CO3 and Cerium Oxides.

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Karel; Leitner, J.; Havlica, Jaromír; Pohořelý, Michael; Brynda, Jiří; Šyc, Michal; Chyou, Y.-P.; Chen, P.-Ch.

    2017-01-01

    Roč. 197, JUN 1 (2017), s. 277-289 ISSN 0016-2361 R&D Projects: GA ČR GC14-09692J Institutional support: RVO:67985858 Keywords : cerium oxides * dehalogenation * thermodynamics Subject RIV: DI - Air Pollution ; Quality OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 4.601, year: 2016

  15. Pulsed laser deposition of bimetallic gold–platinum nanoparticles on cerium oxide and their characterisation by X-ray photoelectron spectroscopy and temperature-programmed desorption of isotopically labelled carbon monoxide

    Czech Academy of Sciences Publication Activity Database

    Plšek, Jan; Bastl, Zdeněk

    2013-01-01

    Roč. 109, MAR 2013 (2013), s. 109-118 ISSN 0021-9517 R&D Projects: GA ČR GA104/08/1501 Institutional support: RVO:61388955 Keywords : pulsed laser deposition * cerium oxide * Au-Pt nanostructures Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 6.073, year: 2013

  16. Thermodynamic Aspects of Gasification Derived Syngas Desulfurization, Removal of Hydrogen Halides and Regeneration of Spent Sorbents Based on La2O3/La2O2CO3 and Cerium Oxides.

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Karel; Leitner, J.; Havlica, Jaromír; Pohořelý, Michael; Brynda, Jiří; Šyc, Michal; Chyou, Y.-P.; Chen, P.-Ch.

    2017-01-01

    Roč. 197, JUN 1 (2017), s. 277-289 ISSN 0016-2361 R&D Projects: GA ČR GC14-09692J Institutional support: RVO:67985858 Keywords : cerium oxides * dehalogenation * thermodynamic s Subject RIV: DI - Air Pollution ; Quality OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 4.601, year: 2016

  17. A combinatorial chemistry approach to the investigation of cerium oxide and plutonium oxide reactions with small molecules

    Science.gov (United States)

    Brady, John T.; Warner, Benjamin P.; Bridgewater, Jon S.; Havrilla, George J.; Morris, David E.; Buscher, C. Thomas

    2000-07-01

    We are currently investigating the potential chemistry of the 3013 Standard waste storage containers. These containers are filled with waste that is a mixture of inorganic salts and plutonium oxide that has been calcined to remove water and other volatiles. There has been concern about possible pressure buildup due to the formation of hydrogen or other gases. We are utilizing a combinatorial chemistry approach to investigate a range of possible reactions that may occur in the containers with various concentrations of metal oxides and inorganic salts.

  18. 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)

  19. 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.

  20. Separation of cerium from other lanthanides by leaching with nitric acid rare earth(III) hydroxide-cerium(IV) oxide mixtures

    International Nuclear Information System (INIS)

    Mioduski, T.; Dong Anh Hao; Hoang Hong Luan

    1989-01-01

    The objective of the present work is a method for separating Ce from other Ln in the raw natural mixtures of rare earth hydroxides obtained from Vietnamese and Mongolian fluorocarbonate ores. The method, a simple acid digestion, should combine a maximum Ln(III) concentration of the effluent solution with a nitrate counter-ion environment and high selectivity vs. leaching yield parameters. Under optimum conditions Ce (and Th, if present) virtually does not pass into solution while the yield of leaching and the sum of REE oxides concentration in the after-leach solution reach the maximum values of 97% (mass) and 0.18 kg x dm -3 , respectively. (author) 9 refs.; 8 tabs

  1. Exposure to Cerium Oxide Nanoparticles Is Associated With Activation of Mitogen-activated Protein Kinases Signaling and Apoptosis in Rat Lungs

    Directory of Open Access Journals (Sweden)

    Kevin M. Rice

    2015-05-01

    Full Text Available Objectives: With recent advances in nanoparticle manufacturing and applications, potential exposure to nanoparticles in various settings is becoming increasing likely. No investigation has yet been performed to assess whether respiratory tract exposure to cerium oxide (CeO2 nanoparticles is associated with alterations in protein signaling, inflammation, and apoptosis in rat lungs. Methods: Specific-pathogen-free male Sprague-Dawley rats were instilled with either vehicle (saline or CeO2 nanoparticles at a dosage of 7.0 mg/kg and euthanized 1, 3, 14, 28, 56, or 90 days after exposure. Lung tissues were collected and evaluated for the expression of proteins associated with inflammation and cellular apoptosis. Results: No change in lung weight was detected over the course of the study; however, cerium accumulation in the lungs, gross histological changes, an increased Bax to Bcl-2 ratio, elevated cleaved caspase-3 protein levels, increased phosphorylation of p38 MAPK, and diminished phosphorylation of ERK-1/2-MAPK were detected after CeO2 instillation (p<0.05. Conclusions: Taken together, these data suggest that high-dose respiratory exposure to CeO2 nanoparticles is associated with lung inflammation, the activation of signaling protein kinases, and cellular apoptosis, which may be indicative of a long-term localized inflammatory response.

  2. 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

  3. Comparison of Elemental Mercury Oxidation Across Vanadium and Cerium Based Catalysts in Coal Combustion Flue Gas: Catalytic Performances and Particulate Matter Effects.

    Science.gov (United States)

    Wan, Qi; Yao, Qiang; Duan, Lei; Li, Xinghua; Zhang, Lei; Hao, Jiming

    2018-03-06

    This paper discussed the field test results of mercury oxidation activities over vanadium and cerium based catalysts in both coal-fired circulating fluidized bed boiler (CFBB) and chain grate boiler (CGB) flue gases. The characterizations of the catalysts and effects of flue gas components, specifically the particulate matter (PM) species, were also discussed. The catalytic performance results indicated that both catalysts exhibited mercury oxidation preference in CGB flue gas rather than in CFBB flue gas. Flue gas component studies before and after dust removal equipment implied that the mercury oxidation was well related to PM, together with gaseous components such as NO, SO 2 , and NH 3 . Further investigations demonstrated a negative PM concentration-induced effect on the mercury oxidation activity in the flue gases before the dust removal, which was attributed to the surface coverage by the large amount of PM. In addition, the PM concentrations in the flue gases after the dust removal failed in determining the mercury oxidation efficiency, wherein the presence of different chemical species in PM, such as elemental carbon (EC), organic carbon (OC) and alkali (earth) metals (Na, Mg, K, and Ca) in the flue gases dominated the catalytic oxidation of mercury.

  4. Nanostructured cerium oxide catalyst support: Effects of morphology on the electro activity of gold toward oxidative sensing of glucose

    International Nuclear Information System (INIS)

    Gougis, Maxime; Tabet-Aoul, Amel; Ma, Dongling; Mohamedi, Mohamed

    2014-01-01

    We report on the fabrication of nanostructured CeO 2 -gold electrodes by means of laser ablation. The synthetic conditions were varied in order to obtain different morphologies of CeO 2 . The physical and chemical properties of the samples were studied by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The effect of the morphology of CeO 2 on the electrocatalytic oxidation of glucose were studied by cyclic voltammetry and square-wave voltammetry. Among the various electrodes fabricated, the CeO 2 coating produced under 10 mTorr of oxygen showed the best supporting catalytic properties for gold by displaying 44 μA cm −2 mM −1 sensitivity for glucose oxidation at near neutral pH values. The detection limit is as low as 10 μM. This electrochemical activity makes the optimized nanostructured electrode potentially useful for non-enzymatic sensing of glucose. (author)

  5. 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

  6. The influence of cerium and yttrium ion implantation upon the oxidation behaviour of a 20% Cr/25% Ni/Nb stabilised stainless steel, in carbon dioxide, at 8250C

    International Nuclear Information System (INIS)

    Bennett, M.J.; Dearnaley, G.; Houlton, M.R.; Hawes, R.W.M.

    1982-01-01

    The influence of cerium and yttrium ion implantation upon the oxidation behaviour of a 20% Cr/25% Ni niobium stabilised stainless steel during up to 7 157h exposure to carbon dioxide, at 825 0 C has been examined. The doses ranged between 5 x 10 14 and 10 17 ions cm -2 . Above thresholds of between 5 x 10 14 and 5 x 10 15 yttrium and between 5 x 10 15 and 10 16 cerium ions cm -2 the implantation of both elements improved the oxidation resistance of the 20/25/Nb steel. Yttrium exerted the greater influence, reducing by a factor of two the attack after 7 157h. Up to 80% of the oxide formed on the 20/25/Nb steel spalled, particularly on thermal cycling. Cerium and yttrium implantation improved oxide adhesion by similar extents, which increased with ion dose such that with the highest doses, no spallation was measurable. The effect of the implanted elements derived from their incorporation within the oxide film. It was initiated by their promotion of the formation of an initial chromium-rich oxide layer, which had a finer grain size than that formed on the 20/25/Nb steel. Reduction in continuing attack was associated in part, with improved oxide adhesion, as this decreased the significant contribution to the attack of the 20/25/Nb steel from the reoxidation of spalled areas. (author)

  7. Synthesis and structural studies on cerium substituted La0.4Ca0.6MnO3 as solid oxide fuel cell electrode material

    Science.gov (United States)

    Singh, Monika; Kumar, Dinesh; Singh, Akhilesh Kumar

    2018-04-01

    For solid oxide fuel cell electrode material, calcium doped lanthanum manganite La0.4Ca0.6MnO3 (LCMO) and cerium-incorporated on Ca-site with composition La0.40Ca0.55Ce0.05MnO3 (LCCMO) were synthesized using most feasible and efficient glycine-nitrate method. The formation of crystalline single phase was confirmed by x-ray diffraction (XRD). The Rietveld analysis reveals that both systems crystallize into orthorhombic crystal structure with Pnma space group. Additionally, 8 mole % Y2O3 stabilized ZrO2 (8YSZ) solid electrolyte was also synthesized using high energy ball mill to check the reaction with electrode materials. It was found that the substitution of Ce+4 cations in LCMO perovskite suppressed formation of undesired insulating CaZrO3 phase.

  8. Corrosion resistance and durability of superhydrophobic surface formed on magnesium alloy coated with nanostructured cerium oxide film and fluoroalkylsilane molecules in corrosive NaCl aqueous solution.

    Science.gov (United States)

    Ishizaki, Takahiro; Masuda, Yoshitake; Sakamoto, Michiru

    2011-04-19

    The corrosion resistant performance and durability of the superhydrophobic surface on magnesium alloy coated with nanostructured cerium oxide film and fluoroalkylsilane molecules in corrosive NaCl aqueous solution were investigated using electrochemical and contact angle measurements. The durability of the superhydrophobic surface in corrosive 5 wt% NaCl aqueous solution was elucidated. The corrosion resistant performance of the superhydrophobic surface formed on magnesium alloy was estimated by electrochemical impedance spectroscopy (EIS) measurements. The EIS measurements and appropriate equivalent circuit models revealed that the superhydrophobic surface considerably improved the corrosion resistant performance of magnesium alloy AZ31. American Society for Testing and Materials (ASTM) standard D 3359-02 cross cut tape test was performed to investigate the adhesion of the superhydrophobic film to the magnesium alloy surface. The corrosion formation mechanism of the superhydrophobic surface formed on the magnesium alloy was also proposed. © 2011 American Chemical Society

  9. An assessment of the validity of cerium oxide as a surrogate for plutonium oxide gallium removal studies

    International Nuclear Information System (INIS)

    Kolman, D.G.; Park, Y.; Stan, M.; Hanrahan, R.J. Jr.; Butt, D.P.

    1999-01-01

    Methods for purifying plutonium metal have long been established. These methods use acid solutions to dissolve and concentrate the metal. However, these methods can produce significant mixed waste, that is, waste containing both radioactive and chemical hazards. The volume of waste produced from the aqueous purification of thousands of weapons would be expensive to treat and dispose. Therefore, a dry method of purification is highly desirable. Recently, a dry gallium removal research program commenced. Based on initial calculations, it appeared that a particular form of gallium (gallium suboxide, Ga 2 O) could be evaporated from plutonium oxide in the presence of a reducing agent, such as small amounts of hydrogen dry gas within an inert environment. Initial tests using ceria-based material (as a surrogate for PuO 2 ) showed that thermally-induced gallium removal (TIGR) from small samples (on the order of one gram) was indeed viable. Because of the expense and difficulty of optimizing TIGR from plutonium dioxide, TIGR optimization tests using ceria have continued. This document details the relationship between the ceria surrogate tests and those conducted using plutonia

  10. Study on soot particle formation and oxidation in DI diesel engine; Chokufunshiki diesel kikan ni okeru susu ryushi no seicho sanka ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Kurata, K; Senda, J; Fujimoto, H [Doshisha University, Kyoto (Japan); Asai, G [Yanmar Diesel Engine Co. Ltd., Osaka (Japan)

    1997-10-01

    To clarify soot formation and oxidation process in diesel combustion, the natural emission of OH radical and the flame temperature were obtained in the combustion chamber of D.I. diesel engine. Further, soot were detected by LII (Laser Induced Incandescence) and LIS (Laser Induced Scattering) technique to assess the relative soot diameter and its number density. OH emission and flame temperature were compared with data of soot diameter and number- density. The results show that : (1) OH emission has relation to flame temperature. (2) OH emission arises latter than soot emission, because early soot at early combustion consume OH to oxidate. (3) As soon as it is ignited, soot particles are formed in the region of low temperature. 6 refs., 7 figs., 2 tabs.

  11. A kinetic and mechanistic study on the oxidation of l-methionine and N-acetyl l-methionine by cerium(IV in sulfuric acid medium

    Directory of Open Access Journals (Sweden)

    T. Sumathi

    2016-09-01

    Full Text Available The kinetics of oxidation of l-methionine and N-acetyl l-methionine by Ce(IV in sulfuric acid–sulfate media in the range of 288.1–298.1 K has been investigated. The major oxidation products of methionine and N-acetyl l-methionine have been identified as methionine sulfoxide and N-acetyl methionine sulfoxide. The major oxidation products have been confirmed by qualitative analysis and boiling point. The reaction was first order with respect to l-methionine, N-acetyl l-methionine and Ce(IV. Increase in [H+], ionic strength and HSO4- did not affect the reaction rate. Under the experimental conditions, Ce4+ was the effective oxidizing species of cerium. Increase in dielectric constant of the medium decreased the reaction rate. Under nitrogen atmosphere, the reaction system can initiate polymerization of acrylonitrile, indicating the generation of free radicals. Activation parameters associated with the overall reaction have been calculated.

  12. Oxidation behaviours of particulate matter emitted by a diesel engine equipped with a NTP device

    International Nuclear Information System (INIS)

    Gao, Jianbing; Ma, Chaochen; Xing, Shikai; Sun, Liwei

    2017-01-01

    Highlights: • Final oxidation temperatures increased for PM aggregation compared with raw PM. • Devolatilized PM aggregation exhibited similar oxidation rate constants. • DSC-based method is more accurate than TGA-based method. - Abstract: To resolve the regeneration problem of non-thermal plasma (NTP) reactor, the oxidation behaviours of diesel particulate matter (PM) were investigated. Oxidation kinetic parameters were calculated using Flynn-Wall-Ozawa (FWO) and Friedman-Reich-Levi (FRL) methods based on thermal gravimetric analyzer (TGA) and differential scanning calorimetry (DSC) results. The DSC-based method avoided the disadvantages of TGA-based method, and the oxidation kinetic parameters calculated using the two methods were compared. The results showed that the effect of plasma on the oxidation behaviours differed greatly for PM sampled at engine loads. The TGA profiles of PM aggregation (collected on the collection plate of NTP reactor) sampled at 60% and 100% engine loads were similar although they differed significantly for raw PM. Devolatilization of raw PM led the TGA profiles to shift slightly to lower temperature, however, the TGA curves shifted to higher temperature for PM aggregation and PM treated with plasma (PM escaping from NTP reactor). The oxidation rate constants of devolatilized PM aggregation sampled at different engine loads were almost the same. DSC-based method revealed the oxidation behaviours and kinetic parameters with more accuracy than TGA-based method.

  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. Ultrafine particles from diesel engines induce vascular oxidative stress via JNK activation.

    Science.gov (United States)

    Li, Rongsong; Ning, Zhi; Cui, Jeffery; Khalsa, Bhavraj; Ai, Lisong; Takabe, Wakako; Beebe, Tyler; Majumdar, Rohit; Sioutas, Constantinos; Hsiai, Tzung

    2009-03-15

    Exposure to particulate air pollution is linked to increased incidences of cardiovascular diseases. Ambient ultrafine particles (UFP) from diesel vehicle engines have been shown to be proatherogenic in ApoE knockout mice and may constitute a major cardiovascular risk in humans. We posited that circulating nano-sized particles from traffic pollution sources induce vascular oxidative stress via JNK activation in endothelial cells. Diesel UFP were collected from a 1998 Kenworth truck. Intracellular superoxide assay revealed that these UFP dose-dependently induced superoxide (O(2)(-)) production in human aortic endothelial cells (HAEC). Flow cytometry showed that UFP increased MitoSOX red intensity specific for mitochondrial superoxide. Protein carbonyl content was increased by UFP as an indication of vascular oxidative stress. UFP also up-regulated heme oxygenase-1 (HO-1) and tissue factor (TF) mRNA expression, and pretreatment with the antioxidant N-acetylcysteine significantly decreased their expression. Furthermore, UFP transiently activated JNK in HAEC. Treatment with the JNK inhibitor SP600125 and silencing of both JNK1 and JNK2 with siRNA inhibited UFP-stimulated O(2)(-) production and mRNA expression of HO-1 and TF. Our findings suggest that JNK activation plays an important role in UFP-induced oxidative stress and stress response gene expression.

  15. Nitric oxide in a diesel engine. Laser-based detection and interpretation

    International Nuclear Information System (INIS)

    Stoffels, G.G.M.

    1999-01-01

    The main objective of the work described in this thesis is the development of a method to determine the nitric oxide (NO) density with both spatial and temporal resolution during the combustion inside the cylinder of a diesel engine by means of laser diagnostics. As a tool to observe the NO molecules the Laser Induced Fluorescence (LIF) technique is used. This non-intrusive technique allows to detect minority species in combustion with spatial and temporal resolution. The intensity of the fluorescence resulting from the NO molecules, that are excited by the laser radiation is a measure for the amount of NO present in the cylinder of the running engine. The engine used is a one-cylinder, two-stroke, direct injection diesel engine. The engine is made optically accessible by mounting two quartz windows in the cylinder wall through which the laser beam can traverse the combustion chamber. A third window is placed in the centre of the cylinder head and is used to detect the fluorescence. The engine was operated in steady-state, on standard commercial diesel fuel and non-oxygen enriched intake air, in contrast to most other experiments reported in literature. In previously described experiments the research engine was mostly operated in skip-fired mode on a substitute fuel and often extra oxygen was supplied to the intake air. The experiments reported in this thesis have shown that it is possible to observe NO inside the combustion chamber of the two-stroke diesel engine applying the LIF technique. 93 refs

  16. 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 

  17. 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.

  18. 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.

  19. 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.

  20. Method of cerium separation from other lanthanides and yttrium

    International Nuclear Information System (INIS)

    Tran, Duc Hiep; Mostecky, J.

    1988-01-01

    Cerium is separated from a suspension produced during the aerial oxidation process. The suspension is subject to a cyclic process of two-stage fractional dissolution. Following the first dissolution, almost all cerium remains undissolved while 95% of the other lanthanides pass into the solution. The filtrate of the second stage of dissolution containing about 5% of ceriumm is returned for oxidation with the next batch of hydroxide mixed concentrate. Following oxidation, the two-stage fractional dissolution is repeated. This cycling provides quantitative cerium separation from other rare earth elements. (E.S.)

  1. 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.

  2. Chemiluminescence from an oxidation reaction of rhodamine B with cerium(IV) in a reversed micellar medium of cetyltrimethylammonium chloride in 1-hexanol-cyclohexane/water.

    Science.gov (United States)

    Hasanin, Tamer H A; Tsunemine, Yusuke; Tsukahara, Satoshi; Okamoto, Yasuaki; Fujiwara, Terufumi

    2011-01-01

    The chemiluminescence (CL) emission, observed when rhodamine B (RB) in 1-hexanol-cyclohexane was mixed with cerium(IV) sulfate in sulfuric acid dispersed in a reversed micellar medium of cetyltrimethylammonium chloride (CTAC) in 1-hexanol-cyclohexane/water, was investigated using a flow-injection system. The CL emission from the oxidation reaction of RB with Ce(IV) was found to be stronger in the CTAC reversed micellar solution compared with an aqueous solution. Bearing on the enhancement effect of the CTAC reverse micelles on the RB-Ce(IV) CL, several studies including stopped-flow, fluorescence and electron spin resonance (ESR) spectrometries were performed. Rapid spectral changes of an intermediate in the RB-Ce(IV) reaction in the aqueous and reversed micellar solutions were successfully observed using a stopped-flow method. The effect of the experimental variables, i.e., oxidant concentration, sulfuric acid concentration, the mole fraction of 1-hexanol, water-to-surfactant molar concentration ratio, flow rate, upon the CL intensity was evaluated. Under the experimental conditions optimized for a flow-injection determination of RB based on the new reversed micellar-mediated CL reaction with Ce(IV), a detection limit of 0.08 µmol dm(-3) RB was achieved, and a linear calibration graph was obtained with a dynamic range from 0.5 to 20 µmol dm(-3). The relative standard deviation (n = 6) obtained at an RB concentration of 3 µmol dm(-3) was 3%.

  3. Use of water containing acetone–butanol–ethanol for NOx-PM (nitrogen oxide-particulate matter) trade-off in the diesel engine fueled with biodiesel

    International Nuclear Information System (INIS)

    Chang, Yu-Cheng; Lee, Wen-Jhy; Wu, Tser Son; Wu, Chang-Yu; Chen, Shui-Jen

    2014-01-01

    Fuel blends that contain biodiesel are known to produce greater NO x (nitrogen oxide) emissions in diesel engine exhaust than regular diesel, and this is one of the key barriers to the wider adoption of biodiesel as an alternative fuel. In this study, a water-containing ABE (acetone–butanol–ethanol) solution, which simulates products that are produced from biomass fermentation without dehydration processing, was tested as a biodiesel-diesel blend additive to lower NO x emissions from diesel engines. The energy efficiency and the PM (particulate matter) and PAHs (polycyclic aromatic hydrocarbons) emissions were investigated and compared under various operating conditions. Although biodiesel had greater NO x emissions, the blends that contained 25% of the water-containing ABE solution had significantly lower NO x (4.30–30.7%), PM (10.9–63.1%), and PAH (polycyclic aromatic hydrocarbon) emissions (26.7–67.6%) than the biodiesel–diesel blends and regular diesel, respectively. In addition, the energy efficiency of this new blend was 0.372–7.88% higher with respect to both the biodiesel–diesel blends and regular diesel. Because dehydration and surfactant addition are not necessary, the application of ABE–biodiesel–diesel blends can simplify fuel production processes, reduce energy consumption, and lower pollutant emissions, meaning that the ABE–biodiesel–diesel blend is a promising green fuel. - Highlights: • Water-containing ABE (acetone–butanol–ethanol)–biodiesel–diesel was tested in a diesel engine. • The addition of ABE to biodiesel–diesel blends can enhance the energy efficiency. • The addition of ABE can solve the problem of NO x -PM (nitrogen oxide-particulate matter) trade-off when using biodiesel. • PAHs (polycyclic aromatic hydrocarbons) can be further reduced by adding ABE in biodiesel–diesel blends. • Fuel production was simplified due to the acceptance of water in ABE

  4. 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...

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

    NARCIS (Netherlands)

    Verbiezen, K.; Vliet, van A.P.; Klein-Douwel, R.J.H.; Ganippa, L.C.; Bougie, H.J.T.; Meerts, W.L.; Dam, N.J.; Meulen, ter J.J.

    2005-01-01

    Quantitative in-cylinder laser-induced fluorescence measurements ofnitric oxide in a heavy-duty Diesel engine are presented. Special attention is paid to experimental techniques to assess the attenuation of the laser beam and the fluorescence signal by the cylinder contents.This attenuation can be

  6. 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

  7. Heterogeneous oxidative desulfurization of diesel fuel catalyzed by mesoporous polyoxometallate-based polymeric hybrid.

    Science.gov (United States)

    Yang, Huawei; Jiang, Bin; Sun, Yongli; Zhang, Luhong; Huang, Zhaohe; Sun, Zhaoning; Yang, Na

    2017-07-05

    In this work, the simple preparation of novel polymer supported polyoxometallates (POMs) catalysts has been reported. Soluble task-specific cross-linked poly (ionic liquid) (PIL) was prepared with N,​N-​dimethyl-​dodecyl-​(4-​vinylbenzyl) ammonium chloride and divinylbenzene as co-monomers. The as-prepared cationic PILs were assembled with different commercial POMs to form the interlinked mesoporous catalysts, and the formation mechanism was provided. The catalytic oxidation activities of the catalysts were closely related to the formation pathway of their corresponding peroxide active species. The catalyst with H 2 W 12 O 42 10- as counterion, which exhibited the best activity in the oxidation of benzothiophene (BT) and dibenzothiophene (DBT) to sulfones in model oil with hydrogen peroxide (H 2 O 2 , 30wt%) as oxidant, was characterized by different techniques and systematically studied for its sulfur removal performance. As for the oxidative desulfurization of a real diesel, it was observed that almost all of the original sulfur compounds could be completely converted, and the catalyst could be reused for at least eight cycles without noticeable changes in both catalytic activity and chemical structure. In the end, a catalytic mechanism was put forward with the assistant of Raman analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Cylinder-averaged histories of nitrogen oxide in a DI diesel with simulated turbocharging

    Science.gov (United States)

    Donahue, Ronald J.; Borman, Gary L.; Bower, Glenn R.

    1994-10-01

    An experimental study was conducted using the dumping technique (total cylinder sampling) to produce cylinder mass-averaged nitric oxide histories. Data were taken using a four stroke diesel research engine employing a quiescent chamber, high pressure direct injection fuel system, and simulated turbocharging. Two fuels were used to determine fuel cetane number effects. Two loads were run, one at an equivalence ratio of 0.5 and the other at a ratio of 0.3. The engine speed was held constant at 1500 rpm. Under the turbocharged and retarded timing conditions of this study, nitric oxide was produced up to the point of about 85% mass burned. Two different models were used to simulate the engine mn conditions: the phenomenological Hiroyasu spray-combustion model, and the three dimensional, U.W.-ERO modified KIVA-2 computational fluid dynamic code. Both of the models predicted the correct nitric oxide trend. Although the modified KIVA-2 combustion model using Zeldovich kinetics correctly predicted the shapes of the nitric oxide histories, it did not predict the exhaust concentrations without arbitrary adjustment based on experimental values.

  9. Evaluation of the role of oxidative stress, inflammation and apoptosis in the pulmonary and the hepatic toxicity induced by cerium oxide nanoparticles following intratracheal instillation in male Sprague-Dawley rats

    Science.gov (United States)

    Nalabotu, Siva Krishna

    The field of nanotechnology is rapidly progressing with potential applications in the automobile, healthcare, electronics, cosmetics, textiles, information technology, and environmental sectors. Nanomaterials are engineered structures with at least one dimension of 100 nanometers or less. With increased applications of nanotechnology, there are increased chances of exposure to manufactured nanomaterials. Recent reports on the toxicity of engineered nanomaterials have given scientific and regulatory agencies concerns over the safety of nanomaterials. Specifically, the Organization for Economic Co-operation and Development (OECD) has identified fourteen high priority nanomaterials for study. Cerium oxide (CeO2) nanoparticles are one among the high priority group. Recent data suggest that CeO2 nanoparticles may be toxic to lung cell lines in vitro and lung tissues in vivo. Other work has proposed that oxidative stress may play an important role in the toxicity; however, the exact mechanism of the toxicity, has to our knowledge, not been investigated. Similarly, it is not clear whether CeO2 nanoparticles exhibit systemic toxicity. Here, we investigate whether pulmonary exposure to CeO2 nanoparticles is associated with oxidative stress, inflammation and apoptosis in the lungs and liver of adult male Sprague-Dawley rats. Our data suggest that the intratracheal instillation of CeO2 nanoparticles can cause an increased lung weight to body weight ratio. Changes in lung weights were associated with the accumulation of cerium in the lungs, elevations in serum inflammatory markers, an increased Bax to Bcl-2 ratio, elevated caspase-3 protein levels, increased phosphorylation of p38-MAPK and diminished phosphorylation of ERK1/2-MAPK. Our findings from the study evaluating the possible translocation of CeO2 nanoparticles from the lungs to the liver suggest that CeO 2 nanoparticle exposure was associated with increased liver ceria levels, elevations in serum alanine transaminase

  10. 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...

  11. Cerium oxalate precipitation

    International Nuclear Information System (INIS)

    Chang, T.P.

    1987-02-01

    Cerium, a nonradioactive, common stand-in for plutonium in development work, has been used to simulate several plutonium precipitation processes at the Savannah River Laboratory. There are similarities between the plutonium trifluoride and the cerium oxalate precipitations in particle size and extent of plating, but not particle morphology. The equilibrium solubility, precipitation kinetics, particle size, extent of plating, and dissolution characteristics of cerium oxalate have been investigated. Interpretations of particle size and plating based on precipitation kinetics (i.e., nucleation and crystal growth) are presented. 16 refs., 7 figs., 6 tabs

  12. Photovoltaic performance and stability of fullerene/cerium oxide double electron transport layer superior to single one in p-i-n perovskite solar cells

    Science.gov (United States)

    Xing, Zhou; Li, Shu-Hui; Wu, Bao-Shan; Wang, Xin; Wang, Lu-Yao; Wang, Tan; Liu, Hao-Ran; Zhang, Mei-Lin; Yun, Da-Qin; Deng, Lin-Long; Xie, Su-Yuan; Huang, Rong-Bin; Zheng, Lan-Sun

    2018-06-01

    Interface engineering that involves in the metal cathodes and the electron transport layers (ETLs) facilitates the simultaneous improvement of device performances and stability in perovskite solar cells (PSCs). Herein, low-temperature solution-processed cerium oxide (CeOx) films are prepared by a facile sol-gel method and employed as the interface layers between [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) and an Ag back contact to form PC61BM/CeOx double ETLs. The introduction of CeOx enables electron extraction to the Ag electrode and protects the underlying perovskite layer and thus improves the device performance and stability of the p-i-n PSCs. The p-i-n PSCs with double PC61BM/CeOx ETLs demonstrate a maximum power conversion efficiency (PCE) of 17.35%, which is superior to those of the devices with either PC61BM or CeOx single ETLs. Moreover, PC61BM/CeOx devices exhibit excellent stability in light soaking, which is mainly due to the chemically stable CeOx interlayer. The results indicate that CeOx is a promising interface modification layer for stable high-efficiency PSCs.

  13. Electrochemical redox processes involving soluble cerium species

    International Nuclear Information System (INIS)

    Arenas, L.F.; Ponce de León, C.; Walsh, F.C.

    2016-01-01

    Highlights: • The relevance of cerium in laboratory and industrial electrochemistry is considered. • The history of fundamental electrochemical studies and applications is considered. • The chemistry, redox thermodynamics and electrode kinetics of cerium are summarised. • The uses of cerium ions in synthesis, energy storage, analysis and environmental treatment are illustrated. • Research needs and development perspectives are discussed. - Abstract: Anodic oxidation of cerous ions and cathodic reduction of ceric ions, in aqueous acidic solutions, play an important role in electrochemical processes at laboratory and industrial scale. Ceric ions, which have been used for oxidation of organic wastes and off-gases in environmental treatment, are a well-established oxidant for indirect organic synthesis and specialised cleaning processes, including oxide film removal from tanks and process pipework in nuclear decontamination. They also provide a classical reagent for chemical analysis in the laboratory. The reversible oxidation of cerous ions is an important reaction in the positive compartment of various redox flow batteries during charge and discharge cycling. A knowledge of the thermodynamics and kinetics of the redox reaction is critical to an understanding of the role of cerium redox species in these applications. Suitable choices of electrode material (metal or ceramic; coated or uncoated), geometry/structure (2-or 3-dimensional) and electrolyte flow conditions (hence an acceptable mass transport rate) are critical to achieving effective electrocatalysis, a high performance and a long lifetime. This review considers the electrochemistry of soluble cerium species and their diverse uses in electrochemical technology, especially for redox flow batteries and mediated electrochemical oxidation.

  14. 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......(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...

  15. Oxidative desulfurization of synthetic diesel using supported catalysts. Part 3. Support effect on vanadium-based catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cedeno-Caero, Luis; Gomez-Bernal, Hilda; Fraustro-Cuevas, Adriana; Guerra-Gomez, Hector D.; Cuevas-Garcia, Rogelio [UNICAT, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria 04510, Mexico D.F. (Mexico)

    2008-04-15

    Oxidesulfurization (ODS) of benzothiophenic compounds prevailing in diesel was conducted with hydrogen peroxide in presence of various catalysts, using a model diesel and actual diesel fuel. ODS activities of dibenzothiophenes (DBTs) in hexadecane for a series of V{sub 2}O{sub 5} catalysts supported on alumina, titania, ceria, niobia and silica, were evaluated. Results show that the oxidation activity of DBTs depends on the support used. It was observed that the sulfone yield is not proportional to textural properties or V content. For all catalysts, ODS of benzothiophene (BT), dibenzothiophene (DBT), 4-methyl dibenzothiophene (4-MDBT) and 4,6-dimethyl dibenzothiophene (4,6-DMDBT) decreased in the following order: DBT > 4-MDBT > 4,6-DMDBT > BT. This trend does not depend on the catalyst used or the textural properties of the catalysts and supports. In presence of indole ODS activities diminish, except with catalysts supported on alumina-titania mixed oxide, whereas with V{sub 2}O{sub 5}/TiO{sub 2} catalyst the performance is the highest. ODS of Mexican diesel fuel was carried out in presence of this catalyst and S level was diminished in about 99%. (author)

  16. Selective catalytic reduction of NO{sub x} with NH{sub 3} over iron-cerium-tungsten mixed oxide catalyst prepared by different methods

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Zhi-bo, E-mail: xzb328@163.com [School of Energy and Power Engineering, University of Shanghai for Science & Technology, Shanghai 200093 (China); Collaborative Innovation Research Institute, University of Shanghai for Science & Technology, Shanghai 200093 (China); Shanghai Power Equipment Research Institute, Shanghai 200240 (China); Liu, Jing; Zhou, Fei; Liu, Dun-yu; Lu, Wei [School of Energy and Power Engineering, University of Shanghai for Science & Technology, Shanghai 200093 (China); Jin, Jing [School of Energy and Power Engineering, University of Shanghai for Science & Technology, Shanghai 200093 (China); Collaborative Innovation Research Institute, University of Shanghai for Science & Technology, Shanghai 200093 (China); Ding, Shi-fa [Shanghai Power Equipment Research Institute, Shanghai 200240 (China)

    2017-06-01

    Highlights: • Iron-cerium-tungsten mixed oxide catalysts were prepared through three different methods. • The effect of preparation methods on the NH{sub 3}-SCR activity and the surface structure properties of catalyst were investigated. • Iron-cerium-tungsten mixed oxide prepared through microwave irradiation assistant critic acid sol-gel shows higher NH{sub 3}-SCR activity. - Abstract: A series of magnetic Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z} catalysts were synthesized by three different methods(Co-precipitation(Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-CP), Hydrothermal treatment assistant critic acid sol-gel method(Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-HT) and Microwave irradiation assistant critic acid sol-gel method(Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-MW)), and the catalytic activity was evaluated for selective catalytic reduction of NO with NH{sub 3}. The catalyst was characterized by XRD, N{sub 2} adsorption-desorption, XPS, H{sub 2}-TPR and NH{sub 3}-TPD. Among the tested catalysts, Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-MW shows the highest NO{sub x} conversion over per gram in unit time with NO{sub x} conversion of 60.8% at 350 °C under a high gas hourly space velocity of 1,200,000 ml/(g h). Different from Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-CP catalyst, there exists a large of iron oxide crystallite(γ-Fe{sub 2}O{sub 3} and α-Fe{sub 2}O{sub 3}) scattered in Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z} catalysts prepared through hydrothermal treatment or microwave irradiation assistant critic acid sol-gel method, and higher iron atomic concentration on their surface. And Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-MW shows higher surface absorbed oxygen concentration and better dispersion compared with Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-HT catalyst. These features were favorable for the high catalytic performance of NO reduction with NH{sub 3} over Fe{sub 0.85}Ce{sub 0.10}W{sub 0.05}O{sub z}-MW catalyst.

  17. Development of a portable, modular unit for the optimization of ultrasound-assisted oxidative desulfurization of diesel

    Science.gov (United States)

    Wan, Meng-Wei

    Due to the stringent rules requiring ultra-low sulfur content in diesel fuels, it is necessary to develop alternative methods of desulfurization of fossil fuel derived oil, such as diesel. Current technology is not sufficient to solve this problem. Ultrasound applied to oxidative desulfurization which combined three complementary techniques: ultrasonication, phase transfer catalysis (PTC) and transition metal catalyzed oxidation, has accomplished high sulfur removal in a short contact time at ambient temperature and atmospheric pressure. This research has successfully demonstrated that the higher oxidation efficiency of BT to BTO and free of any by-products by using tetraoctylammonium fluoride as phase transfer agent. The oxidation rate of BT to BTO increased with increasing the carbon chain length of QAS cations. Under the same length of carbon chain, the oxidation rate of BT to BTO increased with decreasing the molecular size of QAS anions. Moreover, for diesel fuels containing various levels of sulfur content, UAOD process followed by solvent extraction has demonstrated that the sulfur reduction can reach above 95 % removal efficiency or final sulfur content below 15 ppm in mild condition. For large-scale commercial production, this research has successfully developed and operated a continuous desulfurization unit, which consists of a sonoractor, an RF amplifier, a function generator, a pretreatment tank, and a pipeline system. A single unit only needed 2' x 4' x 1' space for installation. The results indicated that the remarkable 92% removal efficiency for the sulfur in marine logistic diesel, even at a treatment rate as high as 25 lb/hour which is approximately 2 barrels per day. Therefore, this sonoreactor demonstrated the feasibility of large-scale operation even in a relatively small installation with low capital investment and maintenance cost. It also ensures the safety considerations by operating with diluted hydrogen peroxide under ambient temperature

  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. TU-H-CAMPUS-TeP2-05: Selective Protection of Normal Tissue by Cerium Oxide Nanoparticles During Radiation Therapy

    International Nuclear Information System (INIS)

    Ouyang, Z; Ngwa, W; Yasmin-Karim, S; Strack, G; Sajo, E

    2016-01-01

    Purpose: Cerium oxide nanoparticles (CONPs) have unique pH dependent properties such that they act as a radical modulator. These properties may be used in radiation therapy (RT) to protect normal tissue. This work investigates the selective radioprotection of CONPs in-vitro and potential for in-situ delivery of CONPs in prostate cancer RT. Methods: i) Normal human umbilical vein endothelial cells (HUVEC) and human prostate cancer cells (PC-3) were treated with 0 or 2 ng/mL CONPs (NP size: 5 nm). 2 Gy of 100 kVp radiation was delivered to the cells 4 hours after the CONP treatment. Cell viability was checked 48 hours later using MTS assays. ii) A prostate tumor was modeled as a 2-cm diameter sphere. CONPs were proposed to be loaded in a hollow radiotherapy fiducial marker. The concentration profile for the CONPs within the tumor was modeled with a previously validated diffusion equation employed in other studies for nanoparticles 10 nm or less. Results: i) Without radiation, cell viability was above 90% when treated with 2 ng/mL CONPs for both HUVEC and PC-3. After irradiation, a slightly higher viability was observed in HUVEC with CONPs than the ones without CONPs, and this effect was not observed in PC-3. ii) Based on the calculations, 2 ng/mL of CONPs could be delivered to normal cells by diffusion with a 1 µg/mL initial concentration within two weeks. Conclusion: We conclude that CONPs can provide selective radioprotection. The delivery of needed concentrations of CONPs is feasible via in-situ release from radiotherapy biomaterials (e.g. fiducials) loaded with the CONPs.

  20. TU-H-CAMPUS-TeP2-05: Selective Protection of Normal Tissue by Cerium Oxide Nanoparticles During Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Ouyang, Z; Ngwa, W [University of Massachusetts Lowell, Lowell, MA (United States); Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (United States); Yasmin-Karim, S [Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (United States); Strack, G; Sajo, E [University of Massachusetts Lowell, Lowell, MA (United States)

    2016-06-15

    Purpose: Cerium oxide nanoparticles (CONPs) have unique pH dependent properties such that they act as a radical modulator. These properties may be used in radiation therapy (RT) to protect normal tissue. This work investigates the selective radioprotection of CONPs in-vitro and potential for in-situ delivery of CONPs in prostate cancer RT. Methods: i) Normal human umbilical vein endothelial cells (HUVEC) and human prostate cancer cells (PC-3) were treated with 0 or 2 ng/mL CONPs (NP size: 5 nm). 2 Gy of 100 kVp radiation was delivered to the cells 4 hours after the CONP treatment. Cell viability was checked 48 hours later using MTS assays. ii) A prostate tumor was modeled as a 2-cm diameter sphere. CONPs were proposed to be loaded in a hollow radiotherapy fiducial marker. The concentration profile for the CONPs within the tumor was modeled with a previously validated diffusion equation employed in other studies for nanoparticles 10 nm or less. Results: i) Without radiation, cell viability was above 90% when treated with 2 ng/mL CONPs for both HUVEC and PC-3. After irradiation, a slightly higher viability was observed in HUVEC with CONPs than the ones without CONPs, and this effect was not observed in PC-3. ii) Based on the calculations, 2 ng/mL of CONPs could be delivered to normal cells by diffusion with a 1 µg/mL initial concentration within two weeks. Conclusion: We conclude that CONPs can provide selective radioprotection. The delivery of needed concentrations of CONPs is feasible via in-situ release from radiotherapy biomaterials (e.g. fiducials) loaded with the CONPs.

  1. The controlled-potential coulometric determination of plutonium based upon cerium oxidation and the Pu022+/Pu4+ valency change

    International Nuclear Information System (INIS)

    Phillips, G.; Crossley, D.; Venkataramana, P.

    1977-09-01

    Conditions have been established enabling plutonium to be oxidised quantitatively to the hexavalent state in the working compartment of a controlled-potential coulometric cell using electrogenerated ceric ion or excess ceric nitrate. The excess ceric ion is reduced in situ electrochemically without reduction of the hexavalent plutonium. The plutonium is then determined controlled-potential coulometrically by reduction to Pu 3+ followed by oxidation to Pu 4+ . The first oxidation step is conducted in molar nitric acid solution containing sulphamic acid but the coulometric determination step is conducted in molar sulphuric acid solution. The results obtained in the coulometric determination step were less satisfactory following oxidation with electrogenerated ceric ion rather than with chemically added ceric nitrate. Using the recommended conditions, 6 mg quantities of plutonium can be determined with an accuracy of 100.06% and a precision of 0.12% (coefficient of variation). The behaviour of chromium, manganese and vanadium impurity is reported. (author)

  2. A Very Simple and Sensitive Spectrofluorimetric Method Based on the Oxidation with Cerium (IV for the Determination of Four Different Drugs in Their Pharmaceutical Formulations

    Directory of Open Access Journals (Sweden)

    Ahad Bavili-Tabrizi, Farshad Bahrami, Hossein Badrouj

    2017-03-01

    Full Text Available Background: Methyldopa is a catecholamine widely used as an antihypertensive agent. Pioglitazone is an oral anti-hyperglycemic agent. It is used for the treatment of diabetes mellitus type 2. A survey of the literature reveals that only one spectrofluorimetric method has been reported for the determination of pioglitazone in pharmaceutical preparations. Atenolol and metoprolol are prescription drugs of the β-blocker class with hypotensive action to treat angina, MI, alcohol syndrome, hypertension, and arrhythmias. A survey of the literature reveals that several spectrofluorimetric methods have been reported for the determination of atenolol and metoprolol in pharmaceutical preparations. In continuing of our studies on the developing of simple and fast spectrofluorimetric methods for determination of drugs and active ingredients, in this work we have developed a spectrofluorimetric method based on the oxidation with cerium (IV for the determination of studied drugs in their pharmaceutical formulations. Methods: A simple, rapid and sensitive spectrofluorimetric method was developed for the determination of studied drugs in pharmaceutical formulations. Proposed method is based on the oxidation of these drugs with Ce (IV to produce Ce (III, and its fluorescence was monitored at 356 ± 3 nm after excitation at 254 ± 3 nm. Results: The variables affecting oxidation of each drug were studied and optimized. Under the experimental conditions used, the calibration graphs were linear over the range of 25-450, 50-550, 15-800 and 15-800 ng/mL in the case of atenolol, metoprolol, pioglitazone and methyldopa, respectively. The limit of detection was found to be 8.27, 16.5, 1.52 and 5.08 ng/mL in the case of atenolol, metoprolol, pioglitazone and methyldopa, respectively. Intra- and inter-day assay precisions, expressed as the relative standard deviation (RSD, were lower than 3% in all cases. Conclusion: The proposed method was applied to the determination of

  3. Effects of ultrafine diesel exhaust particles on oxidative stress generation and dopamine metabolism in PC-12 cells.

    Science.gov (United States)

    Kim, Yong-Dae; Lantz-McPeak, Susan M; Ali, Syed F; Kleinman, Michael T; Choi, Young-Sook; Kim, Heon

    2014-05-01

    A major constituent of urban air pollution is diesel exhaust, a complex mixture of gases, chemicals, and particles. Recent evidence suggests that exposure to air pollution can increase the risk of a fatal stroke, cause cerebrovascular damage, and induce neuroinflammation and oxidative stress that may trigger neurodegenerative diseases, such as Parkinson's disease. The specific aim of this study was to determine whether ultrafine diesel exhaust particles (DEPs), the particle component of exhaust from diesel engines, can induce oxidative stress and effect dopamine metabolism in PC-12 cells. After 24 h exposure to DEPs of 200 nm or smaller, cell viability, ROS and nitric oxide (NO(2)) generation, and levels of dopamine (DA) and its metabolites, (dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA)), were evaluated. Results indicated cell viability was not significantly changed by DEP exposure. However, ROS showed dramatic dose-dependent changes after DEP exposure (2.4 fold increase compared to control at 200 μg/mL). NO(2) levels were also dose-dependently increased after DEP exposure. Although not in a dose-dependent manner, upon DEP exposure, intracellular DA levels were increased while DOPAC and HVA levels decreased when compared to control. Results suggest that ultrafine DEPs lead to dopamine accumulation in the cytoplasm of PC-12 cells, possibly contributing to ROS formation. Further studies are warranted to elucidate this mechanism. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  4. Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

    KAUST Repository

    Caputo, Fanny; De Nicola, Milena; Sienkiewicz, Andrzej; Giovanetti, Anna; Bejarano, Ignacio; Licoccia, Silvia; Traversa, Enrico; Ghibelli, Lina

    2015-01-01

    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

  5. 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.

  6. Determination of plutonium in nitric acid solutions - Method by oxidation by cerium(IV), reduction by iron(II) ammonium sulfate and amperometric back-titration with potassium dichromate

    International Nuclear Information System (INIS)

    1987-01-01

    This International Standard specifies a precise and accurate analytical method for determining plutonium in nitric acid solutions. Plutonium is oxidized to plutonium(VI) in a 1 mol/l nitric acid solution with cerium(IV). Addition of sulfamic acid prevents nitrite-induced side reactions. The excess of cerium(IV) is reduced by adding a sodium arsenite solution, catalysed by osmium tetroxide. A slight excess of arsenite is oxidized by adding a 0.2 mol/l potassium permanganate solution. The excess of permanganate is reduced by adding a 0.1 mol/l oxalic acid solution. Iron(III) is used to catalyse the reduction. A small excess of oxalic acid does not interfere in the subsequent plutonium determination. These reduction and oxidation stages can be followed amperometrically and the plutonium is left in the hexavalent state. The sulfuric acid followed by a measured amount of standardized iron(II) ammonium sulfate solution in excess of that required to reduce the plutonium(VI) to plutonium(IV) is added. The excess iron(II) and any plutonium(III) formed to produce iron(III) and plutonium(IV) is amperometrically back-titrated using a standard potassium dichromate solution. The method is almost specifically for plutonium. It is suitable for the direct determination of plutonium in materials ranging from pure product solutions, to fast reactor fuel solutions with a uranium/plutonium ratio of up to 10:1, either before or after irradiation

  7. 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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  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. Controlled exposure to diesel exhaust and traffic noise - Effects on oxidative stress and activation in mononuclear blood cells

    DEFF Research Database (Denmark)

    Hemmingsen, Jette Gjerke; Møller, Peter; Jantzen, Kim

    2015-01-01

    exhaust (DE) at 276μg/m(3) from a passenger car or filtered air, with co-exposure to traffic noise at 48 or 75dB(A). Gene expression markers of inflammation, (interleukin-8 and tumor necrosis factor), oxidative stress (heme oxygenase (decycling-1)) and DNA repair (8-oxoguanine DNA glycosylase (OGG1)) were...... molecules in leukocyte subtypes. CONCLUSION: 3-h exposure to DE caused no genotoxicity, oxidative stress or inflammation in PBMCs, whereas exposure to noise might cause oxidatively damaged DNA.......Particulate air pollution increases risk of cancer and cardiopulmonary disease, partly through oxidative stress. Traffic-related noise increases risk of cardiovascular disease and may cause oxidative stress. In this controlled random sequence study, 18 healthy subjects were exposed for 3h to diesel...

  10. Selected cerium phase diagrams

    International Nuclear Information System (INIS)

    Gschneidner, K.A. Jr.; Verkade, M.E.

    1974-09-01

    A compilation of cerium alloy phase equilibria data based on the most reliable information available is presented. The binary systems selected are those of cerium with each of the following twenty nine elements which might be commonly found in steels: Al, Sb, As, Bi, Ca, C, Cr, Co, Nb, Cu, Fe, Pb, Mg, Mn, Mo, Ni, N, O, P, Se, Si, Ag, S, Te, Sn, Ti, W, and Zn. A brief discussion, a summary of crystal lattice parameters where applicable, and a list of references is included for each element surveyed. (U.S.)

  11. 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.

  12. 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.

  13. STUDY ON THE NITROGEN OXIDES EMISSIONS GENERATED BY THE DIRECT INJECTION DIESEL ENGINES RUNNING WITH BIODIESEL

    Directory of Open Access Journals (Sweden)

    Doru Cosofret

    2016-05-01

    Full Text Available Currently, research results on the use of mixtures of biofuels with fossil fuels to power diesel engines are controversial in terms of reducing emissions of NO in the exhaust gases of diesel engines. This diversity on the results is due to possibly different type of biodiesel used, the type of engine on which the tests were carried out and the methods and conditions for obtaining these results. Therefore research on biodiesel mixed with diesel is still a matter of study. In this regard, we conducted a laboratory study on a 4-stroke diesel engine naturally aspirated, using different mixtures (10, 15, 20, 25, 30, 40 and 50% of diesel with biodiesel made from rapeseed oil. The study results revealed that the NO emissions of the mixtures used are lower than the same emissions produced when the engine is powered with diesel. Also, the emissions of NO do not have a significant drop in the case of mixtures compared with the diesel fuel.

  14. Production of Monodisperse Cerium Oxide Microspheres with Diameters near 100 µm by Internal Gelation Sol-Gel Methods

    Energy Technology Data Exchange (ETDEWEB)

    Katalenich, Jeffrey A.; Kitchen, Brian B.; Pierson, Bruce

    2018-05-01

    Internal gelation sol-gel methods have used a variety of sphere forming methods in the past to produce metal oxide microspheres, but typically with poor control over the size uniformity at diameters near 100 µm. This work describes efforts to make and measure internal gelation, sol-gel microspheres with very uniform diameters in the 100 – 200 µm size range using a two-fluid nozzle. A custom apparatus was used to form aqueous droplets of sol-gel feed solutions in silicone oil and heat them to cause gelation of the spheres. Gelled spheres were washed, dried, and sintered prior to mounting on glass slides for optical imaging and analysis. Microsphere diameters and shape factors were determined as a function of silicone oil flow rate in a two-fluid nozzle and the size of a needle dispensing the aqueous sol-gel solution. Nine batches of microspheres were analyzed and had diameters ranging from 65.5 ± 2.4 µm for the smallest needle and fastest silicone oil flow rate to 211 ± 4.7 µm for the largest needle and slowest silicone oil flow rate. Standard deviations for measured diameters were less than 8% for all samples and most were less than 4%. Microspheres had excellent circularity with measured shape factors of 0.9 – 1. However, processing of optical images was complicated by shadow effects in the photoresist layer on glass slides and by overlapping microspheres. Based on calculated flow parameters, microspheres were produced in a simple dripping mode in the two-fluid nozzle. Using flow rates consistent with a simple dripping mode in a two-fluid nozzle configuration allows for very uniform oxide microspheres to be produced using the internal-gelation sol-gel method.

  15. 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)

  16. Oxidative damage to DNA by diesel exhaust particle exposure in co-cultures of human lung epithelial cells and macrophages

    DEFF Research Database (Denmark)

    Jantzen, Kim; Roursgaard, Martin; Madsen, Claus Desler

    2012-01-01

    Studies in mono-culture of cells have shown that diesel exhaust particles (DEPs) increase the production of reactive oxygen species (ROS) and oxidative stress-related damage to DNA. However, the level of particle-generated genotoxicity may depend on interplay between different cell types, e.g. lung...... treatment with standard reference DEPs, SRM2975 and SRM1650b. The exposure to DEPs did not affect the colony-forming ability of A549 cells in co-culture with THP-1a cells. The DEPs generated DNA strand breaks and oxidatively damaged DNA, measured using the alkaline comet assay as formamidopyrimidine...... relationship between levels of respiration and ROS production. In conclusion, exposure of mono-cultured cells to DEPs generated oxidative stress to DNA, whereas co-cultures with macrophages had lower levels of oxidatively damaged DNA than A549 epithelial cells....

  17. 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)

  18. Thermoluminescence of magnesium oxide doped with cerium and lithium obtained by a glycine-based solution combustion method

    International Nuclear Information System (INIS)

    Escobar O, F. M.; Orante B, V. R.; Cruz V, C.; Bernal, R.

    2015-10-01

    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 3+ , Li + 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 2 for the annealed powder samples. Photoluminescence emission spectra showed the characteristic Ce 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 3+ , Li + powder obtained by Scs is a promising material for radiation dosimetry applications. (Author)

  19. Role of cerium oxide nanoparticle-induced autophagy as a safeguard to exogenous H2O2-mediated DNA damage in tobacco BY-2 cells.

    Science.gov (United States)

    Sadhu, Abhishek; Ghosh, Ilika; Moriyasu, Yuji; Mukherjee, Anita; Bandyopadhyay, Maumita

    2018-04-13

    The effect of cerium oxide nanoparticle (CeNP) in plants has elicited substantial controversy. While some investigators have reported that CeNP possesses antioxidant properties, others observed CeNP to induce reactive oxygen species (ROS). In spite of considerable research carried out on the effects of CeNP in metazoans, fundamental studies that can unveil its intracellular consequences linking ROS production, autophagy and DNA damage are lacking in plants. To elucidate the impact of CeNP within plant cells, tobacco BY-2 cells were treated with 10, 50 and 250 µg ml-1 CeNP (Ce10, Ce50 and Ce250), for 24 h. Results demonstrated concentration-dependent accumulation of Ca2+ and ROS at all CeNP treatment sets. However, significant DNA damage and alteration in antioxidant defence systems were noted prominently at Ce50 and Ce250. Moreover, Ce50 and Ce250 induced DNA damage, analysed by comet assay and DNA diffusion experiments, complied with the concomitant increase in ROS. Furthermore, to evaluate the antioxidant property of CeNP, treated cells were washed after 24 h (to minimise CeNP interference) and challenged with H2O2 for 3 h. Ce10 did not induce genotoxicity and H2O2 exposure to Ce10-treated cells showed lesser DNA breakage than cells treated with H2O2 only. Interestingly, Ce10 provided better protection over N-acetyl-L-cysteine against exogenous H2O2 in BY-2 cells. CeNP exposure to transgenic BY-2 cells expressing GFP-Atg8 fusion protein exhibited formation of autophagosomes at Ce10. Application of vacuolar protease inhibitor E-64c and fluorescent basic dye acridine orange, further demonstrated accumulation of particulate matters in the vacuole and occurrence of acidic compartments, the autophagolysosomes, respectively. BY-2 cells co-treated with CeNP and autophagy inhibitor 3-methyladenine exhibited increased DNA damage in Ce10 and cell death at all assessed treatment sets. Thus, current results substantiate an alternative autophagy-mediated, antioxidant and

  20. Structure and corrosion behavior of sputter deposited cerium oxide based coatings with various thickness on Al 2024-T3 alloy substrates

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yuanyuan [College of Materials Science and Engineering, Chongqing University, Chongqing 400045 (China); Materials Research Center, Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Huang, Jiamu, E-mail: huangjiamu@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing 400045 (China); Claypool, James B.; Castano, Carlos E. [Materials Research Center, Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); O’Keefe, Matthew J., E-mail: mjokeefe@mst.edu [Materials Research Center, Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States)

    2015-11-15

    Highlights: • Crystalline CeO{sub 2} coatings are deposited on Al 2024-T3 alloys by magnetron sputtering. • The crystal size and internal stress both increased with the thickness of CeO{sub 2} coating. • The ∼210 nm thick coating has the highest adhesion strength to the Al alloy substrate. • The ∼900 nm thick coating increased the corrosion resistance two orders of magnitude. • CeO{sub 2} coatings provide good cathodic inhibition for Al alloys by acting as physical barriers. - Abstract: Cerium oxide based coatings from ∼100 to ∼1400 nm in thickness were deposited onto Al 2024-T3 alloy substrates by magnetron sputtering of a 99.99% pure CeO{sub 2} target. The crystallite size of CeO{sub 2} coatings increased from 15 nm to 46 nm as the coating thickness increased from ∼100 nm to ∼1400 nm. The inhomogeneous lattice strain increased from 0.36% to 0.91% for the ∼100 nm to ∼900 nm thick coatings and slightly decreased to 0.89% for the ∼1400 nm thick coating. The highest adhesion strength to Al alloy substrates was for the ∼210 nm thick coating, due to a continuous film coverage and low internal stress. Electrochemical measurements indicated that sputter deposited crystalline CeO{sub 2} coatings acted as physical barriers that provide good cathodic inhibition for Al alloys in saline solution. The ∼900 nm thick CeO{sub 2} coated sample had the best corrosion performance that increased the corrosion resistance by two orders magnitude and lowered the cathodic current density 30 times compared to bare Al 2024-T3 substrates. The reduced defects and exposed surface, along with suppressed charge mobility, likely accounts for the improved corrosion performance as coating thickness increased from ∼100 nm to ∼900 nm. The corrosion performance decreased for ∼1400 nm thick coatings due in part to an increase in coating defects and porosity along with a decrease in adhesion strength.

  1. 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

    2016-01-01

    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 higher trend

  2. Assigning the Cerium Oxidation State for CH2CeF2 and OCeF2 Based on Multireference Wave Function Analysis.

    Science.gov (United States)

    Mooßen, Oliver; Dolg, Michael

    2016-06-09

    The geometric and electronic structure of the recently experimentally studied molecules ZCeF2 (Z = CH2, O) was investigated by density functional theory (DFT) and wave function-based ab initio methods. Special attention was paid to the Ce-Z metal-ligand bonding, especially to the nature of the interaction between the Ce 4f and the Z 2p orbitals and the possible multiconfigurational character arising from it, as well as to the assignment of an oxidation state of Ce reflecting the electronic structure. Complete active space self-consistent field (CASSCF) calculations were performed, followed by orbital rotations in the active orbital space. The methylene compound CH2CeF2 has an open-shell singlet ground state, which is characterized by a two-configurational wave function in the basis of the strongly mixed natural CASSCF orbitals. The system can also be described in a very compact way by the dominant Ce 4f(1) C 2p(1) configuration, if nearly pure Ce 4f and C 2p orbitals are used. In the basis of these localized orbitals, the molecule is almost monoconfigurational and should be best described as a Ce(III) system. The singlet ground state of the oxygen OCeF2 complex is of closed-shell character when a monoconfigurational wave function with very strongly mixed Ce 4f and O 2p CASSCF natural orbitals is used for the description. The transformation to orbitals localized on the cerium and oxygen atoms leads to a multiconfigurational wave function and reveals characteristics of a mixed valent Ce(IV)/Ce(III) compound. Additionally, the interactions of the localized active orbitals were analyzed by evaluating the expectation values of the charge fluctuation operator and the local spin operator. The Ce 4f and C 2p orbital interaction of the CH2CeF2 compound is weakly covalent and resembles the interaction of the H 1s orbitals in a stretched hydrogen dimer. In contrast, the interaction of the localized active orbitals for OCeF2 shows ionic character. Calculated vibrational Ce

  3. 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

  4. 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.

  5. 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)

  6. Development of a Real-Time Virtual Nitric Oxide Sensor for Light-Duty Diesel Engines

    Directory of Open Access Journals (Sweden)

    Seungha Lee

    2017-03-01

    Full Text Available This study describes the development of a semi-physical, real-time nitric oxide (NO prediction model that is capable of cycle-by-cycle prediction in a light-duty diesel engine. The model utilizes the measured in-cylinder pressure and information obtained from the engine control unit (ECU. From the inputs, the model takes into account the pilot injection burning and mixing, which affects the in-cylinder mixture formation. The representative in-cylinder temperature for NO formation was determined from the mixture composition calculation. The selected temperature and mixture composition was substituted using a simplified form of the NO formation rate equation for the cycle-by-cycle estimation. The reactive area and the duration of NO formation were assumed to be limited by the fuel quantity. The model predictability was verified not only using various steady-state conditions, including the variation of the EGR rate, the boost pressure, the rail pressure, and the injection timing, but also using transient conditions, which represent the worldwide harmonized light vehicles test procedure (WLTC. The WLTC NO prediction results produced less than 3% error with the measured value. In addition, the proposed model maintained its reliability in terms of hardware aging, the changing and artificial perturbations during steady-state and transient engine operations. The model has been shown to require low computational effort because of the cycle-by-cycle, engine-out NO emission prediction and control were performed simultaneously in an embedded system for the automotive application. We expect that the developed NO prediction model can be helpful in emission calibration during the engine design stage or in the real-time controlling of the exhaust NO emission for improving fuel consumption while satisfying NO emission legislation.

  7. Effect of adduct formation on valent state of cerium in its. beta. -diketonates

    Energy Technology Data Exchange (ETDEWEB)

    Spitsyn, V.I.; Martynenko, L.I.; Pechurova, N.I.; Snezhko, N.I.; Murav' eva, I.A.; Anufrieva, S.I. (Moskovskij Gosudarstvennyj Univ. (USSR))

    1982-04-01

    Physicochemical investigation of the system cerium (III, IV)-..beta..-diketone-additional ligand shows that ..beta..-diketonate ability to adduct formation decreases in the series tenoyltrifluoro-acetonate > acetylacetonate > dibenzoylmethanate > benzoylmethanate. Adduct formation of the cerium (III, IV) ..beta..-diketonates stabilizes cerium in trivalent condition, while oxidation degree 4+ is stable in tetrakis-..beta..-diketonates. The additional ligands are arranged in the series: tributhylphosphate < trioctyl-phosphineoxide < triphenylphosphineoxide < ..cap alpha.., ..cap alpha..'-dipyridyl < o-phenanthroline by the effect on cerium (III) stabilization in its ..beta..-diketonates.

  8. Effect of adduct formation on valent state of cerium in its ν-diketonates

    International Nuclear Information System (INIS)

    Spitsyn, V.I.; Martynenko, L.I.; Pechurova, N.I.; Snezhko, N.I.; Murav'eva, I.A.; Anufrieva, S.I.

    1982-01-01

    Physicochemical investigation of the system cerium (III, IV)-ν-diketone-additional ligand shows that ν-diketonate ability to adduct formation decreases in the series tenoyltrifluoro-acetonate > acetylacetonate > dibenzoylmethanate > benzoylmethanate. Adduct formation of the cerium (III, IV) ν-diketonates stabilizes cerium in trivalent condition, while oxidation degree 4+ is stable in tetrakis-ν-diketonates. The additional ligands are arranged in the series: tributhylphosphate < trioctyl-phosphineoxide < triphenylphosphineoxide < α, α'-dipyridyl < o-phenanthroline by the effect on cerium (III) stabilization in its ν-diketonates

  9. 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...

  10. Evaluation of biodiesel fuel and a diesel oxidation catalyst in an underground metal mine : Part 3 : Biological and chemical characterization

    Energy Technology Data Exchange (ETDEWEB)

    Bagley, S.T. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Biological Sciences; Gratz, L.D. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Mechanical Engineering-Engineering Mechanics

    1998-07-24

    A collaborative, international, multidisciplinary effort led to the evaluation of the effects of using a 50 per cent biodiesel fuel blend and an advanced-type diesel oxidation catalyst (DOC) on underground metal mine air quality. The location selected for the field trials was the Creighton Mine 3 in Sudbury, Ontario, operated by Inco. Specifically, part 3 of the study evaluated the effects of using a biodiesel blend fuel on potentially health-related diesel particulate matter (DPM) components, with a special emphasis on polynuclear aromatic hydrocarbons (PAH), nitro-PAH, and mutagenic activity. High volume sampler filters containing submicrometer particles were examined, and comparisons made for DPM and DPM component concentrations. The downwind concentrations of DPM were reduced by 20 per cent with the use of the blend biodiesel fuel as compared with the number 2 diesel fuel with an advanced-type DOC. Significant reductions in solids (up to 30 per cent) and up to 75 per cent in the case of mutagenic activity were noted. Significant reductions in the DPM components potentially harmful to human health should result from the use of this blended fuel combined with an advanced-type DOC in an underground environment. 23 refs., 19 tabs.

  11. Berkelium (4) and cerium (4) extraction with tertiary amines

    International Nuclear Information System (INIS)

    Milyukova, M.S.; Malikov, D.A.; Myasoedov, B.V.

    1978-01-01

    Oxidation of indicator quantities of berkelium and cerium by a mixture of silver nitrate and ammonium persulfate in the solutions of nitric and sulfuric acid has been examined. The stability of the elements in a tetravalent state and their extraction by the solutions of ternary amines have been investigated. It has been established that berkelium and cerium oxidation under these conditions occurs under the effect of ions of divalent silver which is formed owing to oxidation of monovalent silver by peroxide sulfate ions. The following supposition has been put forward: a difference in the behaviour of tetravalent berkelium and cerium during their extraction by ternary amines is explained by their different stability in this state, but not by the formation of complex compounds with nitrate ions

  12. 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.

  13. Experimental investigation of performance and regulated emissions of a diesel engine with Calophyllum inophyllum biodiesel blends accompanied by oxidation inhibitors

    International Nuclear Information System (INIS)

    Rizwanul Fattah, I.M.; Masjuki, H.H.; Kalam, M.A.; Wakil, M.A.; Ashraful, A.M.; Shahir, S.A.

    2014-01-01

    Highlights: • Calophyllum inophyllum biodiesel blends were evaluated using antioxidants. • Blend fuel properties met the ASTM D7467 specification. • Usage of antioxidants provided good stabilization with improved BP and BSFC. • Treated blends showed lower NOx but higher CO and HC compared to untreated blend. - Abstract: Biodiesel having higher unsaturation possesses lower oxidation stability, which needs treatment of oxidation inhibitors or antioxidants. It is expected that antioxidants may affect the clean burning characteristic of biodiesel. Calophyllum inophyllum Linn oil is one of the promising non-edible based feedstock which consists of mostly unsaturated fatty acids. This paper presents an experimental investigation of the antioxidant addition effect on engine performance and emission characteristics. Biodiesel (CIBD) was produced by one step esterification using sulfuric acid (H 2 SO 4 ) as catalyst and one step transesterification using potassium hydroxide (KOH) as a catalyst. Two monophenolic, 2(3)-tert-Butyl-4-methoxyphenol (BHA) and 2,6-di-tert-butyl-4-methylphenol (BHT) and one diphenolic, 2-tert-butylbenzene-1,4-diol (TBHQ) were added at 2000 ppm concentration to 20% CIBD (CIB20). The addition of antioxidants increased oxidation stability without causing any significant negative effect of physicochemical properties. TBHQ showed the greatest capability in increasing stability of CIB20. The tests were carried out using a 55 kW 2.5 L four-cylinder diesel engine at constant load varying speed condition. The performance results indicate that CIB20 showed 1.36% lower mean brake power (BP) and 4.90% higher mean brake specific fuel consumption (BSFC) compared to diesel. The addition of antioxidants increased BP and reduced BSFC slightly. Emission results show that CIB20 increased NOx but decreased CO and HC emission. Antioxidants reduced 1.6–3.6% NOx emission, but increased both CO and HC emission compared to CIB20. However, the level was below the

  14. Studies on the influence of combustion bowl modification for the operation of Cymbopogon flexuosus biofuel based diesel blends in a DI diesel engine

    International Nuclear Information System (INIS)

    Dhinesh, B.; Annamalai, M.; Lalvani, Isaac JoshuaRamesh; Annamalai, K.

    2017-01-01

    Highlights: • A novel biofuel, Cymbopogon flexuosus is used as an alternative energy source. • C20-D80 + 20 ppm profile stayed close to diesel fuel with BB. • Three different combustion bowl CB1, CB2, and CB3 were considered. • Resulting in higher thermal efficiency and lower HC, CO, emission. • Reduction of oxides of nitrogen and smoke emission for C20-D80 + 20 ppm and CB2. - Abstract: The aim of this experimental work is to figure out the optimized the combustion bowl geometry on a constant speed diesel engine for its efficient functioning with a novel biofuel. The novel biofuel considered for this research work was Cymbopogon flexuosus biofuel. To improve the performance level, 20% Cymbopogon flexuosus biofuel was blended with 80% of diesel fuel (C20-D80) and to further reduce the emission magnitude, 20 ppm of cerium oxide was added to the blended fuel (C20-D80 + 20 ppm). For this study four different combustion bowls were designed based on the keen literature survey. They were hemispherical combustion bowl (BB), shallow depth re-entrant combustion bowl (CB1), Toroidal re-entrant combustion bowl (CB2), Toroidal combustion bowl (CB3). Based on the experimental evaluation, the results have been discussed for low load and full load conditions for better understanding. Regarding the fuel modification, C20-D80 + 20 ppm resulted in better engine characteristics owing to combined effect of the oxygen molecule bearing fuel and superior thermal stability and activation energy of the cerium oxide nanoparticle. Of the various bowls considered for the tests, the combustion bowl CB2 showed superior performance and emission reduction compared with its competitors CB1, CB2, and BB. It could have ascribed to the better mixing rate, gain of swirl velocity and the turbulence level of the bowl. CB2 resulted in higher BTE and lower BSEC of 4.1% and 12.02% in low and full load conditions for C20-D80 + 20 ppm. Emission reduction observed was 17% of HC, 43.66% of CO and

  15. Ultrathin, epitaxial cerium dioxide on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Flege, Jan Ingo, E-mail: flege@ifp.uni-bremen.de; Kaemena, Björn; Höcker, Jan; Schmidt, Thomas; Falta, Jens [Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen (Germany); Bertram, Florian [Photon Science, Deutsches Elektronensynchrotron (DESY), Notkestraße 85, 22607 Hamburg (Germany); Wollschläger, Joachim [Department of Physics, University of Osnabrück, Barbarastraße 7, 49069 Osnabrück (Germany)

    2014-03-31

    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 Ce{sub 2}O{sub 3} film may very effectively be converted at room temperature to almost fully oxidized CeO{sub 2} 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.

  16. Combined effect of nanoemulsion and EGR on combustion and emission characteristics of neat lemongrass oil (LGO)-DEE-diesel blend fuelled diesel engine

    International Nuclear Information System (INIS)

    Sathiyamoorthi, R.; Sankaranarayanan, G.; Pitchandi, K.

    2017-01-01

    Highlights: • Neat lemongrass oil can be used as an alternate fuel in diesel engine. • The combined effect of nano emulsion and EGR using LGO25-DEE-Diesel is investigated. • The BTE is improved for nano emulsion fuel blend. • The NO_x and smoke emissions decrease significantly. • Cylinder pressure and Heat release rate increase with longer ignition delay. - Abstract: In the present experimental study, the combined effects of nanoemulsion and exhaust gas recirculation (EGR) on the performance, combustion and emission characteristics of a single cylinder, four stroke, variable compression ratio diesel engine fueled with neat lemongrass oil (LGO)-diesel-DEE (diethyl ether) blend are investigated. The Neat Lemongrass oil could be used as a new alternate fuel in compression ignition engines without any engine modifications. The entire investigation was conducted in the diesel engine using the following test fuels: emulsified LGO25, cerium oxide blended emulsified LGO25 and DEE added emulsified LGO25 with EGR respectively and compared with standard diesel and LGO25 (75% by volume of diesel and 25% by volume of lemongrass oil) fuels. The combined effect of DEE added nano-emulsified LGO25 with EGR yielded a significant reduction in NO_x and smoke emission by 30.72% and 11.2% respectively compared to LGO25. Furthermore, the HC and CO emissions were reduced by 18.18% and 33.31% respectively than with LGO25. The brake thermal efficiency and brake specific fuel consumption increased by 2.4% and 10.8% respectively than LGO25. The combustion characteristics such as cylinder pressure and heat release rate increased by 4.46% and 3.29% respectively than with LGO25. The combustion duration and ignition delay increase at nano-emulsified LGO25 with DEE and EGR mode but decrease for nano-emulsified LGO25 fuel.

  17. Geochemical and microbiological characteristics during in situ chemical oxidation and in situ bioremediation at a diesel contaminated site.

    Science.gov (United States)

    Sutton, Nora B; Kalisz, Mariusz; Krupanek, Janusz; Marek, Jan; Grotenhuis, Tim; Smidt, Hauke; de Weert, Jasperien; Rijnaarts, Huub H M; van Gaans, Pauline; Keijzer, Thomas

    2014-02-18

    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 compatibility with further bioremediation, a pilot scale treatment at a diesel-contaminated location was performed consisting of two persulfate injection events followed by a single nutrient amendment. Groundwater parameters measured throughout the 225 day experiment showed a significant decrease in pH and an increase in dissolved diesel and organic carbon within the treatment area. Molecular analysis of the microbial community size (16S rRNA gene) and alkane degradation capacity (alkB gene) by qPCR indicated a significant, yet temporary impact; while gene copy numbers initially decreased 1-2 orders of magnitude, they returned to baseline levels within 3 months of the first injection for both targets. Analysis of soil samples with sequential extraction showed irreversible oxidation of metal sulfides, thereby changing subsurface mineralogy and potentially mobilizing Fe, Cu, Pb, and Zn. Together, these results give insight into persulfate application in terms of risks and effective coupling with bioremediation.

  18. Role of Oxidative Stress on Diesel-Enhanced Influenza Infection in Mice

    Science.gov (United States)

    Numerous studies have shown that air pollutants, including diesel exhaust (DE), reduce host defenses, resulting in decreased resistance to subsequent respiratory infections. The purpose of this study was to determine if DE exposure could affect the severity of an ongoing influenz...

  19. 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)

  20. DNA damage and defence gene expression after oxidative stress induced by x-rays and diesel exhaust particles

    International Nuclear Information System (INIS)

    Risom, Lotte

    2004-01-01

    Particulate air pollution is one the most important environmental health factors for people living in cities. Especially the exhaust particles from traffic are possible causes for cancer and cardiopulmonary diseases. The aim of this thesis was to characterize the health effects of diesel exhaust particles (DEP) by inducing oxidative stress and analyse the underlying mechanisms. Methods for determining oxidative stress, DNA damage, and gene expression were validated and calibrated in lung tissue by studying the dose response relations after ionizing radiation. The study showed the feasibility of partial-body x-ray irradiation as an in vivo model for induction and repair of oxidative DNA damage, of DNA repair enzymes expression, and antioxidant defense genes. A 'nose-only' mouse model for inhalation of ultra-fine particles showed that particles induce oxidative DNA damage in lung tissue and in bronchoalveolar lavage cells. The exposure increased the expression of HO-1 mRNA and oxoguanine DNA glycosylase OGG1 mRNA. The levels of 8-oxodG and OGG1 mRNA were mirror images. Colon and liver were analysed after administration of DEP in the diet with or without increasing doses of sucrose. This study indicated that DEP induces DNA adducts and oxidative stress through formation of DNA strand breaks, DNA repair enzyme expression, apoptosis, and protein oxidisation in colon and liver at relatively low exposure doses. The thesis is based on four published journal articles. (ln)

  1. DNA damage and defence gene expression after oxidative stress induced by x-rays and diesel exhaust particles

    Energy Technology Data Exchange (ETDEWEB)

    Risom, Lotte

    2004-07-01

    Particulate air pollution is one the most important environmental health factors for people living in cities. Especially the exhaust particles from traffic are possible causes for cancer and cardiopulmonary diseases. The aim of this thesis was to characterize the health effects of diesel exhaust particles (DEP) by inducing oxidative stress and analyse the underlying mechanisms. Methods for determining oxidative stress, DNA damage, and gene expression were validated and calibrated in lung tissue by studying the dose response relations after ionizing radiation. The study showed the feasibility of partial-body x-ray irradiation as an in vivo model for induction and repair of oxidative DNA damage, of DNA repair enzymes expression, and antioxidant defense genes. A 'nose-only' mouse model for inhalation of ultra-fine particles showed that particles induce oxidative DNA damage in lung tissue and in bronchoalveolar lavage cells. The exposure increased the expression of HO-1 mRNA and oxoguanine DNA glycosylase OGG1 mRNA. The levels of 8-oxodG and OGG1 mRNA were mirror images. Colon and liver were analysed after administration of DEP in the diet with or without increasing doses of sucrose. This study indicated that DEP induces DNA adducts and oxidative stress through formation of DNA strand breaks, DNA repair enzyme expression, apoptosis, and protein oxidisation in colon and liver at relatively low exposure doses. The thesis is based on four published journal articles. (ln)

  2. 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)

  3. Characterization of platinized and unplatinized cerium dioxide and other cerium containing catalyst supports

    International Nuclear Information System (INIS)

    Daniel, D.W.

    1984-01-01

    The adsorption of CO on platinized cerium dioxide has been investigated by FTIR (Fourier Transform Infrared Spectroscopy). Four active surface sites and two adsorption geometries were found for the oxidized catalyst. Although the metallic sites and both geometries, linear and bridged, were retained upon reduction the two cationic sites were not. During stepwise desorption, CO dissociates leaving behind adsorbed carbon inhibiting readsorption. At elevated temperatures CeO 2 oxidizes Pt. The large decrease in CO adsorption resulting from high temperature reduction was reversed by reoxidation. XPS (X-ray Photoelectron Spectroscopy) data provided no evidence of encapsulation and XRD (X-ray Diffraction) showed the retention of a constant particle size. The results were interpreted as electronic metal-support interaction. The addition of H 2 or D 2 to adsorbed CO at 25 0 C caused spillover of the CO onto the support and a decrease in CO band frequency. When O 2 was added to preadsorbed CO a new band associated with oxygen and CO coadsorbed on a single Pt atom appeared. Carbon dioxide dissociation at room temperature is proposed to occur via a Langmuir-Hinshelwood mechanism. CO adsorption on platinized titania, silica, ceria/titania, ceria/silica, and cerium titanate has also been studied by the same techniques. The adsorption/desorption behavior of the cerium/titania and the single oxide systems paralleled that of Pt/CeO 2

  4. Evaluation of retrofit crankcase ventilation controls and diesel oxidation catalysts for reducing air pollution in school buses

    Science.gov (United States)

    Trenbath, Kim; Hannigan, Michael P.; Milford, Jana B.

    2009-12-01

    This study evaluates the effect of retrofit closed crankcase ventilation filters (CCFs) and diesel oxidation catalysts (DOCs) on the in-cabin air quality in transit-style diesel school buses. In-cabin pollution levels were measured on three buses from the Pueblo, CO District 70 fleet. Monitoring was conducted while buses were driven along their regular routes, with each bus tested three times before and three times after installation of control devices. Ultrafine number concentrations in the school bus cabins were 33-41% lower, on average, after the control devices were installed. Mean mass concentrations of particulate matter less than 2.5 μm in diameter (PM2.5) were 56% lower, organic carbon (OC) 41% lower, elemental carbon (EC) 85% lower, and formaldehyde 32% lower after control devices were installed. While carbon monoxide concentrations were low in all tests, mean concentrations were higher after control devices were installed than in pre-retrofit tests. Reductions in number, OC, and formaldehyde concentrations were statistically significant, but reductions in PM2.5 mass were not. Even with control devices installed, during some runs PM2.5 and OC concentrations in the bus cabins were elevated compared to ambient concentrations observed in the area. OC concentrations inside the bus cabins ranged from 22 to 58 μg m -3 before and 13 to 33 μg m -3 after control devices were installed. OC concentrations were correlated with particle-bound organic tracers for lubricating oil emissions (hopanes) and diesel fuel and tailpipe emissions (polycyclic aromatic hydrocarbons (PAH) and aliphatic hydrocarbons). Mean concentrations of hopanes, PAH, and aliphatic hydrocarbons were lower by 37, 50, and 43%, respectively, after the control devices were installed, suggesting that both CCFs and DOCs were effective at reducing in-cabin OC concentrations.

  5. Effects of particulate oxidation catalyst on unregulated pollutant emission and toxicity characteristics from heavy-duty diesel engine.

    Science.gov (United States)

    Feng, Xiangyu; Ge, Yunshan; Ma, Chaochen; Tan, Jianwei

    2015-01-01

    To evaluate the effects of particulate oxidation catalyst (POC) on unregulated pollutant emission and toxicity characteristics, polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), soot, soluble organic fractions (SOF) and sulphate emissions emitted from a heavy-duty diesel engine retrofitted with a POC were investigated on a diesel bench. The particulate matter (PM) in the exhaust was collected by Teflon membrane, and the PAHs and VOCs were analysed by a gas chromatography/mass spectrometer (GC/MS). The results indicate that the POC exhibits good performance on the emission control of VOCs, PAHs and PM. The POC and the diesel particulate filters (DPF) both show a good performance on reducing the VOCs emission. Though the brake-specific emission (BSE) reductions of the total PAHs by the POC were lower than those by the DPF, the POC still removed almost more than 50% of the total PAHs emission. After the engine was retrofitted with the POC, the reductions of the PM mass, SOF and soot emissions were 45.2-89.0%, 7.8-97.7% and 41.7-93.3%, respectively. The sulphate emissions decreased at low and medium loads, whereas at high load, the results were contrary. The PAHs emissions were decreased by 32.4-69.1%, and the contributions of the PAH compounds were affected by the POC, as well as by load level. The benzo[a]pyrene equivalent (BaPeq) of PAHs emissions were reduced by 35.9-97.6% with the POC. The VOCs emissions were reduced by 21.8-94.1% with the POC, and the reduction was more evident under high load.

  6. 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 ...

  7. Impact of energy efficiency and replacement of diesel fuel with natural gas in public transport on reducing emissions of nitrogen oxides

    Energy Technology Data Exchange (ETDEWEB)

    Dimitrovski, Dame; Jovanovski, Antonio [Faculty of Mechanical Engineering, ' Ss. Cyril and Methodius' University, Skopje (Macedonia, The Former Yugoslav Republic of)

    2014-07-01

    This paper analyzes the direct emissions of nitrogen oxides from the public transport (bus) in urban areas in the Republic of Macedonia. As influential factors on which to compare the quantity of these emissions are taken: Penetration of new (energy efficient) technologies in bus transport, the intensity of the bus fleet renewal for public transport and replacement of diesel with natural gas. (Author)

  8. Coulometric microdetermination of organic compounds with manganese(III) and cerium(IV)

    International Nuclear Information System (INIS)

    Chateau-Gosselin, M.; Patriarche, G.J.

    1977-01-01

    The oxidation of compounds such as hydroquinon, p-aminophenol, paracetamol and phenacetin was performed using cerium(IV) and manganese(III) coulometrically electrogenerated. Quantitative results obtained are excellent even at the microscale level. (author)

  9. Phase segregation in cerium-lanthanum solid solutions

    NARCIS (Netherlands)

    Belliere, V.; Joorst, G; Stephan, O; de Groot, FMF; Weckhuysen, BM

    2006-01-01

    Electron energy-loss spectroscopy (EELS) in combination with scanning transmission electron microscopy ( STEM) reveals that the La enrichment at the surface of cerium-lanthanum solid solutions is an averaged effect and that segregation occurs in a mixed oxide phase. This separation occurs within a

  10. 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.

  11. Enhanced activity and stability of copper oxide/γ-alumina catalyst in catalytic wet-air oxidation: Critical roles of cerium incorporation

    Science.gov (United States)

    Zhang, Yongli; Zhou, Yanbo; Peng, Chao; Shi, Junjun; Wang, Qingyu; He, Lingfeng; Shi, Liang

    2018-04-01

    By successive impregnation method, the Ce-modified Cu-O/γ-Al2O3 catalyst was prepared and characterized using nitrogen adsorption-desorption, scanning electron microscopy energy dispersive X-ray analysis (SEM-EDS), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman, and H2-Temperature programming reduction (H2-TPR). In catalytic wet-air oxidation (CWAO) process for the printing and dyeing wastewater (PDW), the effects of Ce addition on performance, mechanism and kinetics of the catalyst were investigated. The Ce addition increases the Brunauer-Emmett-Teller (BET) surface area and pore volume of the catalyst and makes the active components uniformly distributed on the catalyst surface. Formation of a stable CuAl2O4 solid solution by anchoring Cu onto the γ-Al2O3 crystal lattice leads to a significant decrease in metal leaching of the Ce-modified catalyst. The proportion of lattice oxygen in the catalyst substantially increases and the apparent activation energy of Cu-O/γ-Al2O3 catalyst decreases owing to Ce addition. Therefore, the catalytic activity and stability of the Ce-modified catalyst are considerably improved. The scavengers experiments identify the active species existed in the CWAO reaction system, with the order of reactivity: h+ > O2•- > H2O2 > HO•. This novel Cu-Ce-O/γ-Al2O3 catalyst has great potential in applications for treatment of concentrated organic wastewater due to its superior catalytic activity and improved stability.

  12. Electrorefining of Cerium in LiCl-KCl Molten Salts

    International Nuclear Information System (INIS)

    Campbell-Kelly, R.P.; Paget, T.J.

    2010-01-01

    Electrorefining of cerium from cerium-gallium alloys has been demonstrated in lithium chloride-potassium chloride salts at temperatures below 500 deg. C, with excellent current efficiencies and high product yields. These experiments are being carried out as non-active trials for a process for the purification of impure actinide metals. The results reported show anodic current efficiencies consistently close to 100%, and in several experiments complete oxidation of the cerium in the feed occurred. The cathodic product is hard and metallic, and incorporates a significant amount of salt into its structure. The product can be consolidated into a dense, pure metal by melting under calcium chloride at 850 deg. C. The yield of this consolidation step varies between 16 and 75%, seeming to depend on the total mass of metal being consolidated and the quality of inert atmosphere. A small-scale electrochemical cell has been demonstrated which will be used in initial active experiments. (authors)

  13. Electronic state of cerium-based catalysts studied by spectroscopic methods (XPS, XAS)

    International Nuclear Information System (INIS)

    Le Normand, F.; Bernhardt, P.; Hilaire, L.; Kili, K.; Maire, G.; Krill, G.

    1987-01-01

    X-ray Photoelectron Spectroscopy (XPS) of the 3d core level of cerium and X-ray Absorption Spectroscopy (XAS) of the L III absorption edge of cerium have been used to study Pd/CeO 2 , Pd-Ce/γAl 2 O 3 and Ce/γAl 2 O 3 catalysts. The oxidation state of cerium was found to decrease with decreasing amounts of cerium on the surface. It was quite close to III for very low contents of cerium (2-3%). For higher cerium contents the oxidation state was nearer to IV but differences between the two methods were found, owing to the fact that XAS is a volume sensitive probe. The oxidation state of cerium was also lower for Pd-Ce/γAl 2 O 3 than for Ce/γAl 2 O 3 , suggesting the formation of Ce III OCl, chlorine coming from the precursor salt of palladium. 15 refs.; 5 figs.; 1 table

  14. 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%.

  15. Biodiesel versus diesel exposure: Enhanced pulmonary inflammation, oxidative stress, and differential morphological changes in the mouse lung

    International Nuclear Information System (INIS)

    Yanamala, Naveena; Hatfield, Meghan K.; Farcas, Mariana T.; Schwegler-Berry, Diane; Hummer, Jon A.; Shurin, Michael R.; Birch, M. Eileen; Gutkin, Dmitriy W.; Kisin, Elena; Kagan, Valerian E.; Bugarski, Aleksandar D.; Shvedova, Anna A.

    2013-01-01

    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. Continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process: An efficient diesel treatment by injection of the aqueous phase.

    Science.gov (United States)

    Rahimi, Masoud; Shahhosseini, Shahrokh; Movahedirad, Salman

    2017-11-01

    A new continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process was developed in order to decrease energy and aqueous phase consumption. In this process the aqueous phase is injected below the horn tip leading to enhanced mixing of the phases. Diesel fuel as the oil phase with sulfur content of 1550ppmw and an appropriate mixture of hydrogen peroxide and formic acid as the aqueous phase were used. At the first step, the optimized condition for the sulfur removal has been obtained in the batch mode operation. Hence, the effect of more important oxidation parameters; oxidant-to-sulfur molar ratio, acid-to-sulfur molar ratio and sonication time were investigated. Then the optimized conditions were obtained using Response Surface Methodology (RSM) technique. Afterwards, some experiments corresponding to the best batch condition and also with objective of minimizing the residence time and aqueous phase to fuel volume ratio have been conducted in a newly designed double-compartment reactor with injection of the aqueous phase to evaluate the process in a continuous flow operation. In addition, the effect of nozzle diameter has been examined. Significant improvement on the sulfur removal was observed specially in lower sonication time in the case of dispersion method in comparison with the conventional contact between two phases. Ultimately, the flow pattern induced by ultrasonic device, and also injection of the aqueous phase were analyzed quantitatively and qualitatively by capturing the sequential images. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. 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.

  18. 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. Les resultats que

  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. The use of cerium(IV) phosphate for the gravimetric determination and separation of cerium

    International Nuclear Information System (INIS)

    Masin, V.; Dolezal, J.

    1978-01-01

    A method for the gravimetric determination of cerium as Ce 3 (PO 4 ) 4 is described. Cerium can be separated from many metals in this form, as well as from permanganate and dichromate; the cerium separated can then be titrated with iron(II) solution. The method was verified for the determination of cerium in a rare earth concentrate. (Auth.)

  1. Modelling the effect of injection pressure on heat release parameters and nitrogen oxides in direct injection diesel engines

    Directory of Open Access Journals (Sweden)

    Yüksek Levent

    2014-01-01

    Full Text Available Investigation and modelling the effect of injection pressure on heat release parameters and engine-out nitrogen oxides are the main aim of this study. A zero-dimensional and multi-zone cylinder model was developed for estimation of the effect of injection pressure rise on performance parameters of diesel engine. Double-Wiebe rate of heat release global model was used to describe fuel combustion. extended Zeldovich mechanism and partial equilibrium approach were used for modelling the formation of nitrogen oxides. Single cylinder, high pressure direct injection, electronically controlled, research engine bench was used for model calibration. 1000 and 1200 bars of fuel injection pressure were investigated while injection advance, injected fuel quantity and engine speed kept constant. The ignition delay of injected fuel reduced 0.4 crank angle with 1200 bars of injection pressure and similar effect observed in premixed combustion phase duration which reduced 0.2 crank angle. Rate of heat release of premixed combustion phase increased 1.75 % with 1200 bar injection pressure. Multi-zone cylinder model showed good agreement with experimental in-cylinder pressure data. Also it was seen that the NOx formation model greatly predicted the engine-out NOx emissions for both of the operation modes.

  2. Procedure for the separation of cerium from crude phosphates and rare earth concentrates

    International Nuclear Information System (INIS)

    Richter, H.; Koenig, O.; Schmitt, A.; Grauss, H.; Freitag, S.

    1986-01-01

    The invention has to do with a procedure for the separation of cerium from crude phosphates and rare earth phosphate concentrates originating from the partial neutralization of nitric crude phosphate decomposition solutions. It is aimed at the cerium separation from the raw material at an early stage of reprocessing without preceding elimination of other components and impurities. The rare earth phosphate concentrates or crude phosphates are dissolved in nitric acid, the Ce 3+ is oxidized with potassium permanganate or magnanese(IV) hydroxide, and cerium(IV) phosphate is precipitated as pure substance by decreasing the acidity of the solution

  3. The study on preparation of high dispersion and pure cerium dioxide for producing automotive exhaust catalysts

    International Nuclear Information System (INIS)

    Le Minh Tuan; Nguyen Trong Hung; Nguyen Thanh Chung

    2003-01-01

    The multi-stage counter-current solvent extraction process using TBP as the solvent has been carried out for purifying cerium and the ammonium carbonate precipitation method has been used to produce the cerium oxide of high dispersion and pure. The flow sheet of extraction system includes 3 extraction stages with O/A = 0.7,2 stripping stages and 4 scrubbing stages with O/A = 5. The condition for ammonium carbonate precipitation, drying and calcination have been investigated and a procedure that seem to be practically suitable to prepare cerium dioxide powder with great specific surface area for producing automotive exhaust catalyst has been proposed. (LMT)

  4. 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.

  5. 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

  6. 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......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 acellullarly, whereas the exposure to urban dust did not generate ROS. ApoE(-/-) mice, which were exposed twice to 0.5 mg/kg of the particles by intratracheal instillation, had unaltered acetylcholine-elicited vasorelaxation in aorta segments. There was unaltered pulmonary expression level of Vcam-1, Icam-1...

  7. Diesel exhaust controls and aftertreatment

    Energy Technology Data Exchange (ETDEWEB)

    Rubeli, B. [Natural Resources Canada, Sudbury, ON (Canada). CANMET Mining and Mineral Sciences Laboratories

    2009-07-01

    This presentation discussed the safe use of diesel fuels in underground mines, with particular reference to advanced technology engines and system technology options for mines. The use of diesel fuels underground requires well designed diesel engines with an effective preventive maintenance programs utilizing diesel emissions testing. The mines must have a well-engineered ventilation system and an adequate air quality monitoring system. An outline of diesel pollutant formation was included in the presentation. Diesel emission control technologies can address localized air quality problems and control emissions at the source. This presentation summarized the best available diesel emission control technologies for underground mines, namely diesel oxidation catalysts (DOC); diesel particulate filters (DPF); active diesel particulate filters (A-DPF); selective catalytic reduction (SCR); water scrubbers; and fume diluters. An emissions control plan using aftertreatment technology should target the vehicles that are the biggest contributors to diesel exhaust. Low sulphur fuel is a prerequisite for most emission control technologies. The successful control of emissions requires knowledge of the high emitting vehicle groups; an integrated ventilation and emission control technology application plan; ambient and tailpipe emissions testing; and training of operators and mechanics. tabs., figs.

  8. Procedure for the separation of cerium from rare earth phosphate mixtures

    International Nuclear Information System (INIS)

    Richter, H.; Grauss, H.; Schmitt, A.; Schade, H.; Lindeholz, M.; Lorenz, E.; Weickart, J.

    1986-01-01

    The invention is concerned with a procedure for the separation of cerium from rare earth concentrates originating from the partial neutralization of nitric crude phosphate decomposition solutions without preceding elimination of impurities from the raw material. The rare earth phosphates are treated with an excess of concentrated nitric acid through which the Ce 3+ , contained in the solution, is oxidized to Ce 4+ and precipitated as cerium(IV) phosphate by neutralization with alkalis

  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.

    2017-05-01

    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. Performance evaluation of a biodiesel fuelled transportation engine retrofitted with a non-noble metal catalysed diesel oxidation catalyst for controlling unregulated emissions.

    Science.gov (United States)

    Shukla, Pravesh Chandra; Gupta, Tarun; Agarwal, Avinash Kumar

    2018-02-15

    In present study, engine exhaust was sampled for measurement and analysis of unregulated emissions from a four cylinder transportation diesel engine using a state-of-the-art FTIR (Fourier transform infrared spectroscopy) emission analyzer. Test fuels used were Karanja biodiesel blend (B20) and baseline mineral diesel. Real-time emission measurements were performed for raw exhaust as well as exhaust sampled downstream of the two in-house prepared non-noble metal based diesel oxidation catalysts (DOCs) and a baseline commercial DOC based on noble metals. Two prepared non-noble metal based DOCs were based on Co-Ce mixed oxide and Lanthanum based perovskite catalysts. Perovskite based DOC performed superior compared to Co-Ce mixed oxide catalyst based DOC. Commercial noble metal based DOC was found to be the most effective in reducing unregulated hydrocarbon emissions in the engine exhaust, followed by the two in-house prepared non-noble metal based DOCs. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Sintering effect on material properties of electrochemical reactors used for removal of nitrogen oxides and soot particles emitted from diesel engines

    DEFF Research Database (Denmark)

    He, Zeming; Andersen, Kjeld Bøhm; Keel, Li

    2010-01-01

    In the present work, 12-layered electrochemical reactors (comprising five cells) with a novel configuration including supporting layer lanthanum strontium manganate (LSM)-yttria stabilised zirconia (YSZ), electrode layer LSM-gadolinia-doped cerium oxide (CGO) and electrolyte layer CGO were...... fabricated via the processes of slurry preparation, tape casting and lamination and sintering. The parameters of porosity, pore size, pore size distribution, shrinkage, flow rate of the sintered reactors and the electrical conductivities of the supporting layer and the electrode in the sintered reactors were...... characterised. The effect of sintering temperature on microstructures and properties of the sintered samples was discussed, and 1,250 °C was determined as the appropriate sintering temperature for reactor production based on the performance requirements for applications. Using the present ceramic processing...

  12. Cyclic thermochemical process for producing hydrogen using cerium-titanium compounds

    Science.gov (United States)

    Bamberger, C.E.

    A thermochemical cyclic process for producing hydrogen employs the reaction between ceric oxide and titanium dioxide to form cerium titanate and oxygen. The titanate is treated with an alkali metal hydroxide to give hydrogen, ceric oxide, an alkali metal titanate and water. Alkali metal titanate and water are boiled to give titanium dioxide which, along with ceric oxide, is recycled.

  13. Rudolph Diesel

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. Rudolph Diesel. Articles written in Resonance – Journal of Science Education. Volume 17 Issue 4 April 2012 pp 406-424 Classics. Diesel's Rational Heat Motor · Rudolph Diesel · More Details Fulltext PDF ...

  14. The comparison of oxidative thermokinetics between emulsion and microemulsion diesel fuel

    International Nuclear Information System (INIS)

    Leng, Lijian; Yuan, Xingzhong; Zeng, Guangming; Wang, Hou; Huang, Huajun; Chen, Xiaohong

    2015-01-01

    Highlights: • Microemulsion fuel (>90 days) was much more stable than emulsion (≈2 days). • Microemulsification decreased activation energy of the fuel system by 5 kJ mol −1 . • Emulsification increased activation energy of the fuel system by 15 kJ mol −1 . • Microemulsification was more competitive for fuel upgrading than emulsification. - Abstract: Water fuel emulsion has been widely studied with the advantages of saving energy, enhancing engine torque, improving engine performance, and reducing the pollutant emissions. However, it has unfavorable disadvantages such as phase separation and long ignition delay. Water fuel microemulsion with rhamnolipid as the surfactant was formed in this study and characterized in comparison to water fuel emulsion. Water fuel microemulsion was thermodynamically stable without phase separation after 90 days vs. the milky-white emulsion fuel, separated within 2 days. In the thermogravimetric analysis, the TG and DTG curves were shifted to higher temperatures as the increment of heating rate. However, the shift for emulsion at 40 K min −1 was inconspicuous, which implies the reduction in heat transfer, mass transfer, and vaporization rates and further the lengthened ignition delay upon combustion in diesel engine. The activation energies (E a ) predicted by Ozawa–Flynn–Wall (OFW), Kissinger–Akhira–Sunose (KAS), and Starink’s methods indicate that the formation of microemulsion could decrease the activation energy of the fuel by about 5 kJ mol −1 , while the formation of emulsion would increase by 15 kJ mol −1 . The lower activation energy of microemulsion fuel is an indication of easy ignition or shortened ignition delay. Thus, microemulsification may be a more competitive technique for fuel upgrading compared to emulsification

  15. Silver-promoted catalyst for removal of nitrogen oxides from emission of diesel engines

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, K.; Tsujimura, K. [New ACE Institute Co., Ltd., Ibaraki (Japan); Shinoda, K.; Kato, T. [Mitsui Mining and Smelting Co., Ltd. Ageo, Saitama (Japan)

    1996-02-29

    Removal of NO{sub x} from diesel exhaust gas using C{sub 3}H{sub 6}, CH{sub 3}OH or (CH{sub 3}){sub 2}O as a reducing agent was investigated on Ag/Al{sub 2}O{sub 3}, Ag/ZSM-5 and Ag/mordenite catalysts over a wide range of temperatures. Among them, (CH{sub 3}){sub 2}O was found to be suitable for the elimination of NO{sub x} over Ag/mordenite catalyst at the relatively low temperature of 200C to 350C. CH{sub 3}OH was suitable over Ag/Al{sub 2}O{sub 3} catalyst from 350C to 450C while the Ag/mordenite catalyst using (CH{sub 3}){sub 2}O was superior to the Ag/Al{sub 2}O{sub 3} catalyst using CH{sub 3}OH with respect to the temperature range. The Ag/ZSM-5 catalyst had a poor elimination ability when compared with Ag/Al{sub 2}O{sub 3} and Ag/mordenite catalysts. The effects of Ag on mordenite and Al{sub 2}O{sub 3} were also investigated. It was found that Ag improved the removal of NO{sub x} in the higher range of temperatures with mordenite, while Ag improved the removal of NO{sub x} in the lower temperature range with Al{sub 2}O{sub 3}. It was concluded that Ag/mordenite catalyst using (CH{sub 3}){sub 2}O as a reducing agent has a good ability for NO{sub x} removal over a wide range of temperatures

  16. 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.

  17. Application of persulfate-oxidation foam spraying as a bioremediation pretreatment for diesel oil-contaminated soil.

    Science.gov (United States)

    Bajagain, Rishikesh; Lee, Sojin; Jeong, Seung-Woo

    2018-05-15

    This study investigated a persulfate-bioaugmentation serial foam spraying technique to remove total petroleum hydrocarbons (TPHs) present in diesel-contaminated unsaturated soil. Feeding of remedial agents by foam spraying increased the infiltration/unsaturated hydraulic conductivity of reagents into the unsaturated soil. Persulfate mixed with a surfactant solution infiltrated the soil faster than peroxide, resulting in relatively even soil moisture content. Persulfate had a higher soil infiltration tendency, which would facilitate its distribution over a wide soil area, thereby enhancing subsequent biodegradation efficiency. Nearly 80% of soil-TPHs were degraded by combined persulfate-bioaugmentation foam spraying, while bioaugmentation foam spraying alone removed 52%. TPH fraction analysis revealed that the removal rate for the biodegradation recalcitrant fraction (C 18 to C 22 ) in deeper soil regions was higher for persulfate-bioaugmentation serial foam application than for peroxide-bioaugmentation foam application. Persulfate-foam spraying may be superior to peroxide for TPH removal even at a low concentration (50 mN) because persulfate-foam is more permeable, persistent, and does not change soil pH in the subsurface. Although the number of soil microbes declines by oxidation pretreatment, bioaugmentation-foam alters the microbial population exponentially. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Oxidation of Commercial Petronas Diesel with Tert-Butyl Hydroperoxide Over Poly molybdate Alumina Supported Catalyst Modified With Alkaline Earth Metals

    International Nuclear Information System (INIS)

    Wan Nazwanie Wan Abdullah; Rusmidah Ali; Wan Azlee Wan Abu Bakar

    2016-01-01

    Due to strict environmental legislation for ultra-low sulfur diesel fuels, increasing technical and operational challenges are imposed to conventional hydrodesulfurization (HDS) technology. Therefore, catalytic oxidative desulfurization (Cat-ODS) has been suggested to be an alternative method to replace a conventional method which is hydrodesulfurization. In this study, catalytic oxidation of commercial diesel was performed using an oil-soluble oxidant, tert-butyl hydroperoxide (TBHP), over poly molybdate supported on alumina MoO_3-PO_4/ Al_2O_3 catalyst. A commercial Petronas diesel with 440 ppm of total sulfur was employed to evaluate the elimination of sulfur compounds. Besides, the percentage of sulfur removal was measured by (GC-FPD). Alkaline earth metals, such as Calcium (Ca), Barium (Ba) and Strontium (Sr) were introduced on the surface of MoO_3-PO_4/ Al_2O_3. The results showed that the catalytic activity decreased in the order, Ca/ MoO_3-PO_4/ Al_2O_3>Sr/ MoO_3-PO_4/ Al_2O_3> Ba/ MoO_3-PO_4/ Al_2O_3. The Ca/ MoO_3-PO_4/ Al_2O_3 catalyst was characterized by XRD and FESEM. XRD results showed that the best catalyst was highly amorphous while FESEM micrograph illustrated an aggregation and agglomeration of various particle sizes. The catalytic activity of Ca/ MoO_3-PO_4/ Al_2O_3 catalyst with various Ca/ Mo ratios were also studied. When the Ca/ Mo ratio was 15:85, the sulfur removal was the highest (79 %) at 45 degree Celsius, 30 min and O/ S molar ratio 3.0 with solvent = dimethylformamide (DMF), diesel/ solvent ratio = 1.0. (author)

  19. Effect of antioxidant on the oxidation stability and combustion–performance–emission characteristics of a diesel engine fueled with diesel–biodiesel blend

    International Nuclear Information System (INIS)

    Rashedul, H.K.; Masjuki, H.H.; Kalam, M.A.; Teoh, Y.H.; How, H.G.; Rizwanul Fattah, I.M.

    2015-01-01

    Highlights: • Alexandrian laurel or Calophyllum inophyllum biodiesel blend fulfill the ASTM (D7467) specification. • Addition of antioxidant to biodiesel higher the oxidation stability. • Antioxidant treated blends showed lower NO X and BSFC compared to untreated blend. • Antioxidant treated blends showed higher CO, HC and smoke compared to untreated blend. - Abstract: Alexandrian laurel or Calophyllum inophyllum oil is recently considered one of the most anticipated nonconsumable or nonedible biodiesel sources. An attempt has been made in this study to increase the oxidation stability and investigate the engine performance, emission, and combustion characteristics of a diesel engine by adding 1% (by vol.) of two antioxidants, such as 2,6-Di-tert.-butyl-4-methylphenol and 2,2′-methylenebis (4-methyl-6-tert-butylphenol), in higher percentages of C. inophyllum biodiesel (CB30) with diesel fuel (B0). The experiment was performed on a single-cylinder, water-cooled, direct-injection diesel engine for this purpose. The addition of both antioxidants increased the oxidation stability without significantly changing other physicochemical properties. Results also show that the antioxidants enhanced the start of combustion of biodiesel, which resulted in a short ignition delay. The peak pressure and the peak heat release rate during premixed combustion phase of pure CB30 and its modified blend with antioxidant were higher than those of B0. Both antioxidant blends showed higher brake power, higher brake thermal efficiency, and lower brake specific fuel consumption than pure CB30. Both antioxidants significantly reduced NO X emission; however, CO, HC, and smoke opacity were slightly higher than those of CB30. Based on this study, Alexandrian laurel or C. inophyllum biodiesel blend (CB30) with antioxidant can be used as an alternative fuel in a diesel engine without modifications.

  20. 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.

  1. Storage of Nitrous Oxide (NOx in Diesel Engine Exhaust Gas using Alumina-Based Catalysts: Preparation, Characterization, and Testing

    Directory of Open Access Journals (Sweden)

    A. Alsobaai

    2017-03-01

    Full Text Available This work investigated the nitrous oxide (NOx storage process using alumina-based catalysts (K2 O/Al2 O3 , CaO/Al2 O3,  and BaO/Al2 O3 . The feed was a synthetic exhaust gas containing 1,000 ppm of nitrogen monoxide (NO, 1,000 ppm i-C4 H10 , and an 8% O2  and N2  balance. The catalyst was carried out at temperatures between 250–450°C and a contact time of 20 minutes. It was found that NOx was effectively adsorbed in the presence of oxygen. The NOx storage capacity of K2 O/Al2 O3 was higher than that of BaO/Al2 O3.  The NOx storage capacity for K2 O/Al2 O3  decreased with increasing temperature and achieved a maximum at 250°C. Potassium loading higher than 15% in the catalyst negatively affected the morphological properties. The combination of Ba and K loading in the catalyst led to an improvement in the catalytic activity compared to its single metal catalysts. As a conclusion, mixed metal oxide was a potential catalyst for de-NOx process in meeting the stringent diesel engine exhaust emissions regulations. The catalysts were characterized by a number of techniques and measurements, such as X-ray diffraction (XRD, electron affinity (EA, a scanning electron microscope (SEM, Brunner-Emmett-Teller (BET to measure surface area, and pore volume and pore size distribution assessments.

  2. Oxidative desulfurization of model diesel via dual activation by a protic ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Lü, Hongying, E-mail: hylv@ytu.edu.cn; Wang, Shunan; Deng, Changliang; Ren, Wanzhong; Guo, Baocun

    2014-08-30

    Highlights: • A protic ionic liquid, [Hnmp]HCOO, was used as in ODS. • The mechanism of ODS was involved in dual activation by the PIL. • The [Hnmp]HCOO exhibited high catalytic activity in ODS. • The amounts of PILs and oxidant dosage play vital roles in desulfurization system. • This system can be recycled five times with an unnoticeable decrease in activity. - Abstract: A novel and green carboxylate-anion-based protic ionic liquid (PIL), [Hnmp]HCOO, was prepared through a simple and atom economic neutralization reaction between N-methyl-2-pyrrolidonium (NMP) and formic acids. Both FT-IR spectra and {sup 1}H NMR confirmed its simple salt structure. [Hnmp]HCOO exhibited so high catalytic activity that the dibenzothiophene (DBT) removal reached 99% at 50 °C in 3 h under conditions of V{sub PIL}/V{sub model} {sub oil} = 1:10 and H{sub 2}O{sub 2}/DBT (O/S, molar ratio) = 5. The catalytic oxidation reactivity of S-compounds was found to be in the order of DBT > 4,6-dimethyldibenzothiophene (4,6-DMDBT) > benzothiophene (BT). The investigation on mechanism showed that oxidative desulfurization was realized through dual activation of PIL. Moreover, [Hnmp]HCOO can be recycled for five times with an unnoticeable decrease in desulfurization activity.

  3. Oxidative desulfurization of model diesel via dual activation by a protic ionic liquid

    International Nuclear Information System (INIS)

    Lü, Hongying; Wang, Shunan; Deng, Changliang; Ren, Wanzhong; Guo, Baocun

    2014-01-01

    Highlights: • A protic ionic liquid, [Hnmp]HCOO, was used as in ODS. • The mechanism of ODS was involved in dual activation by the PIL. • The [Hnmp]HCOO exhibited high catalytic activity in ODS. • The amounts of PILs and oxidant dosage play vital roles in desulfurization system. • This system can be recycled five times with an unnoticeable decrease in activity. - Abstract: A novel and green carboxylate-anion-based protic ionic liquid (PIL), [Hnmp]HCOO, was prepared through a simple and atom economic neutralization reaction between N-methyl-2-pyrrolidonium (NMP) and formic acids. Both FT-IR spectra and 1 H NMR confirmed its simple salt structure. [Hnmp]HCOO exhibited so high catalytic activity that the dibenzothiophene (DBT) removal reached 99% at 50 °C in 3 h under conditions of V PIL /V model oil = 1:10 and H 2 O 2 /DBT (O/S, molar ratio) = 5. The catalytic oxidation reactivity of S-compounds was found to be in the order of DBT > 4,6-dimethyldibenzothiophene (4,6-DMDBT) > benzothiophene (BT). The investigation on mechanism showed that oxidative desulfurization was realized through dual activation of PIL. Moreover, [Hnmp]HCOO can be recycled for five times with an unnoticeable decrease in desulfurization activity

  4. Valence instabilities in cerium intermetallics

    International Nuclear Information System (INIS)

    Dijkman, W.H.

    1982-01-01

    The primary purpose of this investigation was to study the magnetic behaviour of cerium in intermetallic compounds, that show an IV behaviour, e.g. CeSn 3 . In the progress of the investigations, it became of interest to study the effect of changes in the lattice of the IV compound by substituting La or Y for Ce, thus constituting the Cesub(1-x)Lasub(x)Sn 3 and Cesub(1-x)Ysub(x)Sn 3 quasibinary systems. A second purpose was to examine the possibility of introducing instabilities in the valency of a trivalent intermetallic cerium compound: CeIn 3 , also by La and Y-substitutions in the lattice. Measurements on the resulting Cesub(1-x)Lasub(x)In 3 and Cesub(1-x)Ysub(x)In 3 quasibinaries are described. A third purpose was to study the (gradual) transition from a trivalent cerium compound into an IV cerium compound. This was done by examining the magnetic properties of the CeInsub(x)Snsub(3-x) and CePbsub(x)Snsub(3-x) systems. Finally a new possibility was investigated: that of the occurrence of IV behaviour in CeSi 2 , CeSi, and in CeGa 2 . (Auth.)

  5. A reduced chemical kinetic model for the analytical investigations on the oxidation kinetics and performance characteristics of diesel fuel

    International Nuclear Information System (INIS)

    Selvaraj, N.; Manoj Kumar, C.V.; Babu, M.S.

    2010-01-01

    A detailed study of the combustion of diesel fuel has been conducted analytically using a kinetic scheme with 767 elementary reactions and 158 species. A program has been developed in MATLAB for the analysis of ignition delay, performance, soot formation and emission characteristics of diesel fuel. Nitrogen is considered as the diluent and its percentage is assumed as 79%. The criteria used for the determination of ignition delay time are based on OH concentration to reach a value of 1x10 -9 . A brief review of diesel combustion and soot formation is given. (author)

  6. 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

  7. A kinetic and mechanistic study on the oxidation of l-methionine and N-acetyl l-methionine by cerium(IV) in sulfuric acid medium

    OpenAIRE

    T. Sumathi; P. Shanmugasundaram; G. Chandramohan

    2016-01-01

    The kinetics of oxidation of l-methionine and N-acetyl l-methionine by Ce(IV) in sulfuric acid–sulfate media in the range of 288.1–298.1 K has been investigated. The major oxidation products of methionine and N-acetyl l-methionine have been identified as methionine sulfoxide and N-acetyl methionine sulfoxide. The major oxidation products have been confirmed by qualitative analysis and boiling point. The reaction was first order with respect to l-methionine, N-acetyl l-methionine and Ce(IV). I...

  8. Oxidative desulfurization of model diesel via dual activation by a protic ionic liquid.

    Science.gov (United States)

    Lü, Hongying; Wang, Shunan; Deng, Changliang; Ren, Wanzhong; Guo, Baocun

    2014-08-30

    A novel and green carboxylate-anion-based protic ionic liquid (PIL), [Hnmp]HCOO, was prepared through a simple and atom economic neutralization reaction between N-methyl-2-pyrrolidonium (NMP) and formic acids. Both FT-IR spectra and (1)H NMR confirmed its simple salt structure. [Hnmp]HCOO exhibited so high catalytic activity that the dibenzothiophene (DBT) removal reached 99% at 50°C in 3h under conditions of VPIL/Vmodel oil=1:10 and H2O2/DBT (O/S, molar ratio)=5. The catalytic oxidation reactivity of S-compounds was found to be in the order of DBT>4,6-dimethyldibenzothiophene (4,6-DMDBT)>benzothiophene (BT). The investigation on mechanism showed that oxidative desulfurization was realized through dual activation of PIL. Moreover, [Hnmp]HCOO can be recycled for five times with an unnoticeable decrease in desulfurization activity. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. 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.

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

  11. An assessment on performance, combustion and emission behavior of a diesel engine powered by ceria nanoparticle blended emulsified biofuel

    International Nuclear Information System (INIS)

    Annamalai, M.; Dhinesh, B.; Nanthagopal, K.; SivaramaKrishnan, P.; Isaac JoshuaRamesh Lalvani, J.; Parthasarathy, M.; Annamalai, K.

    2016-01-01

    Highlights: • A novel biofuel, lemongrass is used as a renewable energy source. • Emulsion prepared using 5% of water, 93% of lemongrass oil and 2% of surfactant. • Emulsified nano biofuel performance profile stayed closer to diesel fuel. • Drastic reduction in HC, CO, NO_X and marginal decrease of smoke compared with diesel. - Abstract: The consequence of using cerium oxide (CeO_2) nanoparticle as additive in Lemongrass Oil (LGO) emulsion fuel was experimentally investigated in a single cylinder, constant speed diesel engine. A novel biofuel plant was introduced in this project, namely lemongrass whose binomial name is Cymbopogon flexuosus. The main objective of the project is to reduce the level of harmful pollutants in the exhaust such as unburned hydrocarbon (HC), carbon monoxide (CO), oxides of nitrogen (NO_X), and smoke. The engine performance could also be increased due to the addition of CeO_2 nanoparticle. The LGO emulsion fuel was prepared in the proportion of 5% of water, 93% of LGO and 2% of span80 by volume basis. Span80 acted as surfactant and it would reduce surface tension between the liquids with a hydrophilic-lipophilic balance (HLB) value of 4.2. The ceria nanoparticle was dispersed with the LGO emulsion fuel in the dosage of 30 ppm (ppm). The diesel engine performance, combustion behavior and emission magnitude were compared with diesel and LGO as the base fuels. The whole investigation was conducted with a single cylinder diesel engine using the following fuels, namely neat diesel, neat LGO, LGO emulsion and LGO nano emulsion fuels respectively. The LGO emulsion fuel could reduce smoke and NO_X emissions and could improve Brake Thermal Efficiency (BTE), Brake Specific Energy Consumption (BSEC) compared with neat LGO despite the marginal increase in HC and CO emissions. For ceria nanoparticle blended test fuel, the drastic reduction of carbon monoxide (CO), unburned hydrocarbon (HC), oxides of nitrogen (NO_X) and marginal decrease of

  12. Part 3. Assessment of genotoxicity and oxidative stress after exposure to diesel exhaust from U.S. 2007-compliant diesel engines: report on 1- and 3-month exposures in the ACES bioassay.

    Science.gov (United States)

    Hallberg, L M; Ward, J B; Hernandez, C; Ameredes, B T; Wickliffe, J K

    2012-09-01

    Human health hazards due to diesel exhaust (DE*) exposure have been associated with both solvent and combustion components. In the past, diesel engine exhaust components have been linked to increased mutagenicity in cultures of Salmonella typhimurium and mammalian cells (Tokiwa and Ohnishi 1986). In addition, DE has been shown to increase both the incidence of tumors and the induction of 8-hydroxy-deoxyguanosine adducts (8-OHdG) in ICR mice (Ichinose et al. 1997). Furthermore, DE is composed of a complex mixture of polycyclic aromatic hydrocarbons (PAHs) and particulates. One such PAH, 3-nitrobenzanthrone (3-NBA), has been identified in DE and found in urban air. 3-NBA has been observed to induce micronucleus formation in DNA of human hepatoma cells (Lamy et al. 2004). The purpose of the current research, which is part of the Advanced Collaborative Emissions Study (ACES), a multidisciplinary program being carried out by the Health Effects Institute and the Coordinating Research Council, is to determine whether improvements in the engineering of heavy-duty diesel engines reduce the oxidative stress and genotoxic risk associated with exposure to DE components. To this end, the genotoxicity and oxidative stress of DE from an improved diesel engine was evaluated in bioassays of tissues from Wistar Han rats and C57BL/6 mice exposed to DE. Genotoxicity was measured as strand breaks using an alkaline-modified comet assay. To correlate possible DNA damage found by the comet assay, measurement of DNA-adduct formation was evaluated by a competitive enzyme-linked immunosorbent assay (ELISA) to determine the levels of free 8-OHdG found in the serum of the animals exposed to DE. 8-OHdG is a specific modified base indicating an oxidative type of DNA damage to DNA nucleotides. In addition, a thiobarbituric acid reactive substances (TBARS) assay was used to assess oxidative stress and damage in the form of lipid peroxidation in the hippocampus region of the brains of DE

  13. 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 (NO x ) 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 NO x 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 NO x 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/NO x 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 NO x emission as well as the estimation of exhaust-induced HONO/NO x 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/NO x 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/NO x ratios varied from 0.16 to 1.00 %. The HONO/NO x 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/NO x ratio of 0.8% has possibly linked to underestimation of the total HONO

  14. 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

  15. Cerium neodymium oxide solid solution synthesis as a potential analogue for substoichiometric AmO{sub 2} for radioisotope power systems

    Energy Technology Data Exchange (ETDEWEB)

    Watkinson, E.J., E-mail: ejw36@le.ac.uk [Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom); Ambrosi, R.M. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom); Williams, H.R. [Department of Engineering, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom); Sarsfield, M.J. [National Nuclear Laboratory, Central Laboratory, Sellafield, Seascale, Cumbria, CA20 1PG (United Kingdom); Stephenson, K. [European Space Agency, ESTEC TEC-EP, Keplerlaan 1, Noordwijk, 2201AZ (Netherlands); Weston, D.P. [Department of Engineering, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom); Marsh, N.; Haidon, C. [Department of Geology, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom)

    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 AmO{sub 2-(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) Ce{sub 1-x}Nd{sub x}O{sub 2-(x/2)} oxides with 0.5 < x < 0.7 could be used as a surrogate for some Ia-3 AmO{sub 2-(x/2)}. A new Ce{sub 1-x}Nd{sub x}O{sub 2-(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. - Highlights: •A European radioisotope power systems fuel option is AmO{sub 2-(x/2)} i.e. AmO{sub 1.65} to AmO{sub 1.75} that stays cubic with temperature. •Superstructure (Ia-3) Ce{sub 1-x}Nd{sub x}O{sub 2-(x/2)} is proposed as a surrogate for some Ia-3 AmO{sub 2-(x/2)} phases. •Continuously precipitated oxalates were calcined to oxides. An x of 0.6 was targeted by the nitrate feeds’ molar ratio. •Powder X-ray diffraction and Raman spectroscopy confirmed Ia-3 Ce{sub 1-x}Nd{sub x}O{sub 2-(x/2)}. Samples had Nd/[Ce+Nd] ratios or x of 0.62. •Oxalate particles precipitated at 60 °C had larger modal sizes than those at 25 °C. Lath/plate-like particles were made.

  16. Use of aluminum oxides, titanium and cerium in the production of ceramic composites for protective coating of storage tanks and transportation of oil raw

    International Nuclear Information System (INIS)

    Rego, S.A.B.C.; Ferreira, R.A.S.; Yadava, Y.P.

    2012-01-01

    The deployment of the Abreu e Lima refinery in the port of SUAPE - PE will increase the need to store oil in the region, it is essential to research and develop new materials inert to chemical attack promoted by oil. In this work, we produce the ceramic composite alumina-titania, ceria of high mechanical strength which is observed that with additions of titanium oxide in the order of 15% and 20% better results are obtained as possibly indicating these composites suitable for use in coating ceramic storage tanks of crude oil. (author)

  17. 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...

  18. Carbonation of cerium oxychloride

    International Nuclear Information System (INIS)

    Peterson, E.J.; Onstott, E.I.; Bowman, M.G.

    1977-01-01

    Cerous carbonates can be used in thermochemical cycles for H production if the resulting ceric oxides can be converted back into cerous carbonates. One way is to reduce and hydrolyze ceric oxide with HCl to produce CeOCl and then to carbonate it. The reaction 3CeOCl + 3CO 2 + 8H 2 O → CeCl 3 (aq) + Ce 2 (CO 3 ) 3 . 8H 2 O was found to occur in aqueous medium if the final CeCl 3 content is low. Carbonation of CeOCl could also be conducted in acetone --H 2 O . CeClCO 3 . 3H 2 O was decomposed and characterized. The reactions which can be used for water splitting are discussed briefly

  19. Interfacial redox reaction-directed synthesis of silver@cerium oxide core-shell nanocomposites as catalysts for rechargeable lithium-air batteries

    Science.gov (United States)

    Liu, Ying; Wang, Man; Cao, Lu-Jie; Yang, Ming-Yang; Ho-Sum Cheng, Samson; Cao, Chen-Wei; Leung, Kwan-Lan; Chung, Chi-Yuen; Lu, Zhou-Guang

    2015-07-01

    A facile oxidation-reduction reaction method has been implemented to prepare pomegranate-like Ag@CeO2 multicore-shell structured nanocomposites. Under Ar atmosphere, redox reaction automatically occurs between AgNO3 and Ce(NO3)3 in an alkaline solution, where Ag+ is reduced to Ag nanopartilces and Ce3+ is simultaneously oxidized to form CeO2, followed by the self-assembly to form the pomegranate-like multicore-shell structured Ag@CeO2 nanocomposites driven by thermodynamic equilibrium. No other organic amines or surfactants are utilized in the whole reaction system and only NaOH instead of organic reducing agent is used to prevent the introduction of a secondary reducing byproduct. The as-obtained pomegranate-like Ag@CeO2 multicore-shell structured nanocomposites have been characterized as electro-catalysts for the air cathode of lithium-air batteries operated in a simulated air environment. Superior electrochemical performance with high discharge capacity of 3415 mAh g-1 at 100 mA g-1, stable cycling and small charge/discharge polarization voltage is achieved, which is much better than that of the CeO2 or simple mixture of CeO2 and Ag. The enhanced properties can be primarily attributed to the synergy effect between the Ag core and the CeO2 shell resulting from the unique pomegranate-like multicore-shell nanostructures possessing plenty of active sites to promote the facile formation and decomposition of Li2O2.

  20. Oxidation and low temperature properties of biofuels obtained from pyrolysis and alcoholysis of soybean oil and their blends with petroleum diesel

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Brajendra K. [Food and Industrial Oil Research Unit, National Center for Agricultural Utilization Research, United States Department of Agriculture, Agricultural Research Service, 1815N. University St., Peoria, IL 61604 (United States); Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Suarez, Paulo A.Z. [Food and Industrial Oil Research Unit, National Center for Agricultural Utilization Research, United States Department of Agriculture, Agricultural Research Service, 1815N. University St., Peoria, IL 61604 (United States); LMC-IQ, Universidade de Brasilia, CP 4478, CEP 70919-970, Brasilia-DF (Brazil); Perez, Joseph M. [Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Erhan, Sevim Z. [Food and Industrial Oil Research Unit, National Center for Agricultural Utilization Research, United States Department of Agriculture, Agricultural Research Service, 1815N. University St., Peoria, IL 61604 (United States)

    2009-10-15

    Diesel-like fuels were synthesized by a pyrolysis method using soybean oil (pyrodiesel, PD) and soybean soapstock (SPD), respectively, as starting material. These pyrodiesel samples were compared with soy biodiesel (BD) samples. All these three biofuels (PD, SPD and BD) and their blends with high sulfur (HSD) and low sulfur (LSD) diesel fuels were evaluated by measuring a number of fuel properties, such as oxidative stability, low-temperature performance, acid value and corrosion properties. Compared to BD blends, PD and SPD and their blends were found to have better oxidative stability, though inferior acid values. SPD and its blends have better flow performance at low-temperature compared to BD and PD blends. All the biofuels and their blends met the copper corrosion requirement prescribed by US and European standard. Based on the results reported here, pyrodiesels from these two-different feedstocks have potential and will require some upgrading or change in pyrolysis conditions, if they are to be used as fuel blending component. (author)

  1. Dissolution properties of cerium dibutylphosphate corrosion inhibitors

    NARCIS (Netherlands)

    Soestbergen, van M.; 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

  2. Oxidative mobilization of cerium and uranium and enhanced release of "immobile" high field strength elements from igneous rocks in the presence of the biogenic siderophore desferrioxamine B

    Science.gov (United States)

    Kraemer, Dennis; Kopf, Sebastian; Bau, Michael

    2015-09-01

    Polyvalent trace elements such as the high field strength elements (HFSE) are commonly considered rather immobile during low-temperature water-rock interaction. Hence, they have become diagnostic tools that are widely applied in geochemical studies. We present results of batch leaching experiments focused on the mobilization of certain HFSE (Y, Zr, Hf, Th, U and rare earth elements) from mafic, intermediate and felsic igneous rocks in the presence and absence, respectively, of the siderophore desferrioxamine B (DFOB). Our data show that DFOB strongly enhances the mobility of these trace elements during low-temperature water-rock interaction. The presence of DFOB produces two distinct features in the Rare Earths and Yttrium (REY) patterns of leaching solutions, regardless of the mineralogical and chemical composition or the texture of the rock type studied. Bulk rock-normalized REY patterns of leaching solutions with DFOB show (i) a very distinct positive Ce anomaly and (ii) depletion of La and other light REY relative to the middle REY, with a concave downward pattern between La and Sm. These features are not observed in experiments with hydrochloric acid, acetic acid or deionized water. In DFOB-bearing leaching solutions Ce and U are decoupled from and selectively enriched relative to light REY and Th, respectively, due to oxidation to Ce(IV) and U(VI). Oxidation of Ce3+ and U4+ is promoted by the significantly higher stability of the Ce(IV) and U(VI) DFOB complexes as compared to the Ce(III) and U(IV) DFOB complexes. This is similar to the relationship between the Ce(IV)- and Ce(III)-pentacarbonate complexes that cause positive Ce anomalies in alkaline lakes. However, while formation of Ce(IV) carbonate complexes is confined to alkaline environments, Ce(IV) DFOB complexes may produce positive Ce anomalies even in mildly acidic and near-neutral natural waters. Siderophore-promoted dissolution processes also significantly enhance mobility of other 'immobile' HFSE

  3. 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.

  4. 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).

  5. 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.

  6. Deep Desulfurization of Diesel Fuels with Plasma/Air as Oxidizing Medium, Diperiodatocuprate (III) as Catalyzer and Ionic Liquid as Extraction Solvent

    Science.gov (United States)

    Ban, Lili; Liu, Ping; Ma, Cunhua; Dai, Bin

    2013-12-01

    In this paper, the oxidative desulfurization (ODS) system is directly applied to deal with the catalytic oxidation of sulfur compounds of sulfur-containing model oil by dielectric barrier discharge (DBD) plasma in the presence of air plus an extraction step with the oxidation-treated fuel put over ionic liquid [BMIM]FeCl4 (1-butyl-3-methylimidazolium tetrachloroferrate). This new system exhibited an excellent desulfurization effect. The sulfur content of DBT in diesel oil decreased from 200 ppm to 4.92 ppm (S removal rate up to 97.5%) under the following optimal reaction conditions: air flow rate (ν) of 60 mL/min, amplitude of applied voltage (U) on DBD of 16 kV, input frequency (f) of 79 kHz, catalyst amount (ω) of 1.25 wt%, reaction time (t) of 10 min. Moreover, a high desulfurization rate was obtained during oxidation of benzothiophene (BT) or 4,6-DMDBT (4,6-dimethyl-dibenzothiophene) under the aforementioned conditions. The oxidation reactivity of different S compounds was decreased in the order of DBT, 4,6-DMDBT and BT. The remarkable advantage of the novel ODS system is that the desulfurization condition applies in the presence of air at ambient conditions without peroxides, aqueous solvent or biphasic oil-aqueous solution system.

  7. Deep Desulfurization of Diesel Fuels with Plasma/Air as Oxidizing Medium, Diperiodatocuprate (III) as Catalyzer and Ionic Liquid as Extraction Solvent

    International Nuclear Information System (INIS)

    Ban Lili; Liu Ping; Ma Cunhua; Dai Bin

    2013-01-01

    In this paper, the oxidative desulfurization (ODS) system is directly applied to deal with the catalytic oxidation of sulfur compounds of sulfur-containing model oil by dielectric barrier discharge (DBD) plasma in the presence of air plus an extraction step with the oxidation-treated fuel put over ionic liquid [BMIM]FeCl 4 (1-butyl-3-methylimidazolium tetrachloroferrate). This new system exhibited an excellent desulfurization effect. The sulfur content of DBT in diesel oil decreased from 200 ppm to 4.92 ppm (S removal rate up to 97.5%) under the following optimal reaction conditions: air flow rate (ν) of 60 mL/min, amplitude of applied voltage (U) on DBD of 16 kV, input frequency (f) of 79 kHz, catalyst amount (ω) of 1.25 wt%, reaction time (t) of 10 min. Moreover, a high desulfurization rate was obtained during oxidation of benzothiophene (BT) or 4,6-DMDBT (4,6-dimethyl-dibenzothiophene) under the aforementioned conditions. The oxidation reactivity of different S compounds was decreased in the order of DBT, 4,6-DMDBT and BT. The remarkable advantage of the novel ODS system is that the desulfurization condition applies in the presence of air at ambient conditions without peroxides, aqueous solvent or biphasic oil-aqueous solution system. (plasma technology)

  8. Crystalline cerium(IV) phosphates

    International Nuclear Information System (INIS)

    Herman, R.G.; Clearfield, A.

    1976-01-01

    The ion exchange behaviour of seven crystalline cerium(IV) phosphates towards some of the alkali metal cations is described. Only two of the compounds (A and C) possess ion exchange properties in acidic solutions. Four others show some ion exchange characteristics in basic media with some of the alkali cations. Compound G does not behave as an ion exchanger in solutions of pH + , but show very little Na + uptake. Compound E undergoes ion exchange with Na + and Cs + , but not with Li+. Both Li + and Na + are sorbed by compounds A and C. The results are indicative of structures which show steric exclusion phenomena. (author)

  9. Remarkable changes in the photoluminescent properties of Y2Ce2O7:Eu(3+) red phosphors through modification of the cerium oxidation states and oxygen vacancy ordering.

    Science.gov (United States)

    Raj, Athira K V; Prabhakar Rao, P; Sreena, T S; Sameera, S; James, Vineetha; Renju, U A

    2014-11-21

    A new series of red phosphors based on Eu(3+)-doped yttrium cerate [Y1.9Ce2O7:0.1Eu(3+), Y2Ce1.9O7:0.1Eu(3+) and Y2Ce2-xO7:xEu(3+) (x = 0.05, 0.10, 0.15, 0.20, 0.25 and 0.50)] was prepared via a conventional solid-state method. The influence of the substitution of Eu(3+) at the aliovalent site on the photoluminescent properties was determined by powder X-ray diffraction, FT Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy with energy-dispersive spectroscopy, UV-visible absorption spectroscopy, photoluminescence spectroscopy and lifetime measurements. The substitution of Eu(3+) at the Ce(4+) site induces a structural transition from a defect fluorite to a C-type structure, which increases the oxygen vacancy ordering and the distortion of the Eu(3+) environment, and decreases the formation of Ce(3+) states. In contrast, phosphors with isovalent substitution at the Y(3+) site exhibit the biphasic nature of defect fluorite and a C-type structure, thereby increasing the number of Ce(3+) oxidation states. These modifications resulted in remarkable changes in the photoluminescent properties of Y2Ce1.9O7:0.1Eu(3+) red phosphors, with emission intensities 3.8 times greater than those of the Ce0.9O2:0.1Eu(3+) and Y1.9Ce2O7:0.1Eu(3+). The photoluminescent properties of Y2Ce2-xO7:xEu(3+) were studied at different Eu(3+) concentrations under excitation with blue light. These phosphors emit intense red light due to the (5)D0-(7)F2 transition under excitation at 466 nm and no concentration quenching is observed with up to 50 mol% Eu(3+). They show increased lifetimes in the range 0.62-0.72 ms at Eu(3+) concentrations. The cation ordering linked to the oxygen vacancy ordering led to the uniform distribution of Eu(3+) ions in the lattice, thus allowing higher doping concentrations without quenching and consequently increasing the lifetime of the (5)D0 states. Our results demonstrate that significant improvements in

  10. The effects of cerium doping on the size, morphology, and optical properties of α-hematite nanoparticles for ultraviolet filtration

    Energy Technology Data Exchange (ETDEWEB)

    Cardillo, Dean [Institute for Superconducting and Electronic Materials, AIIM Facility, University of Wollongong Innovation Campus, Squires Way, North Wollongong, NSW 2500 (Australia); Konstantinov, Konstantin, E-mail: konstan@uow.edu.au [Institute for Superconducting and Electronic Materials, AIIM Facility, University of Wollongong Innovation Campus, Squires Way, North Wollongong, NSW 2500 (Australia); Devers, Thierry [Centre de Recherche sur la Matière Divisée, Institut de Physique, site de Chartres, Université d’Orléans (France)

    2013-11-15

    Highlights: • Possible application of cerium-doped α-hematite as ultraviolet filter. • Nanoparticles obtained through co-precipitation technique using various cerium doping levels followed by annealing. • Comprehensive materials characterisation utilizing XRD, DSC/TGA, STEM, UV–vis spectroscopy. • Increasing cerium content reduces particle sizing and alters morphology. • Solubility of cerium in hematite seen between 5 and 10% doping, 10% cerium doping greatly enhances attenuation in ultraviolet region and increases optical bandgap. - Abstract: Metal oxide nanoparticles have potential use in energy storage, electrode materials, as catalysts and in the emerging field of nanomedicine. Being able to accurately tailor the desirable properties of these nanoceramic materials, such as particle size, morphology and optical bandgap (E{sub g}) is integral in the feasibility of their use. In this study we investigate the altering of both the structure and physical properties through the doping of hematite (α-Fe{sub 2}O{sub 3}) nanocrystals with cerium at a range of concentrations, synthesised using a one-pot co-precipitation method. This extremely simple synthesis followed by thermal treatment results in stable Fe{sub 2−x}Ce{sub x}O{sub y} nanoceramics resulting from the burning of any unreacted precursors and transformation of goethite-cerium doped nanoparticle intermediate. The inclusion of Ce into the crystal lattice of these α-Fe{sub 2}O{sub 3} nanoparticles causes a significantly large reduction in mean crystalline size and alteration in particle morphology with increasing cerium content. Finally we report an increase optical semiconductor bandgap, along with a substantial increase in the ultraviolet attenuation found for a 10% Ce-doping concentration which shows the potential application of cerium-doped hematite nanocrystals to be used as a pigmented ultraviolet filter for cosmetic products.

  11. Influence of turbulence-chemistry interaction for n-heptane spray combustion under diesel engine conditions with emphasis on soot formation and oxidation

    Science.gov (United States)

    Bolla, Michele; Farrace, Daniele; Wright, Yuri M.; Boulouchos, Konstantinos; Mastorakos, Epaminondas

    2014-03-01

    The influence of the turbulence-chemistry interaction (TCI) for n-heptane sprays under diesel engine conditions has been investigated by means of computational fluid dynamics (CFD) simulations. The conditional moment closure approach, which has been previously validated thoroughly for such flows, and the homogeneous reactor (i.e. no turbulent combustion model) approach have been compared, in view of the recent resurgence of the latter approaches for diesel engine CFD. Experimental data available from a constant-volume combustion chamber have been used for model validation purposes for a broad range of conditions including variations in ambient oxygen (8-21% by vol.), ambient temperature (900 and 1000 K) and ambient density (14.8 and 30 kg/m3). The results from both numerical approaches have been compared to the experimental values of ignition delay (ID), flame lift-off length (LOL), and soot volume fraction distributions. TCI was found to have a weak influence on ignition delay for the conditions simulated, attributed to the low values of the scalar dissipation relative to the critical value above which auto-ignition does not occur. In contrast, the flame LOL was considerably affected, in particular at low oxygen concentrations. Quasi-steady soot formation was similar; however, pronounced differences in soot oxidation behaviour are reported. The differences were further emphasised for a case with short injection duration: in such conditions, TCI was found to play a major role concerning the soot oxidation behaviour because of the importance of soot-oxidiser structure in mixture fraction space. Neglecting TCI leads to a strong over-estimation of soot oxidation after the end of injection. The results suggest that for some engines, and for some phenomena, the neglect of turbulent fluctuations may lead to predictions of acceptable engineering accuracy, but that a proper turbulent combustion model is needed for more reliable results.

  12. Modelling and Simulation of Packed Bed Catalytic Converter for Oxidation of Soot in Diesel Powered Vehicles Flue Gas

    Directory of Open Access Journals (Sweden)

    Mohammad Nasikin

    2010-10-01

    Full Text Available Diesel vehicle is used in Indonesia in very big number. This vehicle exhausts pollutants especially diesel soot that can be reduces by using a catalytic converter to convert the soot to CO2. To obtain the optimal dimension of catalytic converter it is needed a model that can represent the profile of soot weight, temperature and pressure along the catalytic converter. In this study, a model is developed for packed bed catalytic converter in an adiabatic condition based on a kinetic study that has been  reported previously. Calculation of developed equations in this model uses Polymath 5.X solver with Range Kutta Method. The simulation result shows that temperature profile along catalytic converter increases with the decrease of soot weight,  while pressure profile decreases. The increase of soot weight in entering gas increases the needed converter length. On the other hand, the increase of catalyst diameter does not affect to soot weight along converter and temperature profile, but results a less pressure drop. For 2.500 c diesel engine, packed bed catalytic converter with ellipse's cross sectional of 14,5X7,5 cm diagonal and 0,8 cm catalyst particle diameter, needs 4,1 cm length.

  13. Extraction-differential-photometric method to determine rare earths of cerium subgroup

    International Nuclear Information System (INIS)

    Askerov, D.N.; Gusejnov, I.K.; Melikov, A.A.

    1985-01-01

    The extraction - photometric method to determine great quantities of rare earths of the cerium subgroup as a complex with antipyrine A and diphenylguanidine is developed. Isobutyl and n-butyl alcohols are used as extractants. It is established that proportional dependence between relative optical density and concentration of rare earths of the cerium subgroup in the solution takes place in the concentration interval of 10.3-14.7 μg of rare earths in 1 ml of the solution. Determination error is+-1.12%. The technique is used to determine rare earths of the cerium subgroup in rare earth oxides of a mixed composition, as well as in monozite and loparite

  14. 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

  15. 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 (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). PMID:24688402

  16. 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).

  17. moteur diesel

    African Journals Online (AJOL)

    A board diagnostic system based on the use of fuzzy pattern recognition techniques was ... with model - Classification. ... ensemble de modèles du moteur diesel avec et .... classes). Nous nous plaçons dans le cas d'un apprentissage non supervisé car on ne connait ..... of noise in clustering, Pattern Recognition Letters,.

  18. Rudolf Diesel

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 4. Rudolf Diesel - The Rational Inventor of a Heat Engine. Tilottama Shrinivasa. Article-in-a-Box Volume 17 Issue 4 April 2012 pp 319-320. Fulltext. Click here to view fulltext PDF. Permanent link:

  19. A real time zero-dimensional diagnostic model for the calculation of in-cylinder temperatures, HRR and nitrogen oxides in diesel engines

    International Nuclear Information System (INIS)

    Finesso, Roberto; Spessa, Ezio

    2014-01-01

    Highlights: • Real-time zero-dimensional three-zone diagnostic combustion model. • Capable of evaluating in-cylinder temperatures, HRR and NOx in DI diesel engines. • Able to be integrated in the engine ECU for control applications. • Able to be integrated in the test bed acquisition software for calibration tasks. • Tested under both steady state and fast transient conditions. - Abstract: A real-time zero-dimensional diagnostic combustion model has been developed and assessed to evaluate in-cylinder temperatures, HRR (heat release rate) and NOx (nitrogen oxides) in DI (Direct Injection) diesel engines under steady state and transient conditions. The approach requires very little computational time, that is, of the order of a few milliseconds, and is therefore suitable for real-time applications. It could, for example, be implemented in an ECU (Engine Control Unit) for the on-board diagnostics of combustion and emission formation processes, or it could be integrated in acquisition software installed on an engine test bench for indicated analysis. The model could also be used for post-processing analysis of previously acquired experimental data. The methodology is based on a three-zone thermodynamic model: the combustion chamber is divided into a fuel zone, an unburned gas zone and a stoichiometric burned gas zone, to which the energy and mass conservation equations are applied. The main novelty of the proposed method is that the equations can be solved in closed form, thus making the approach suitable for real-time applications. The evaluation of the temperature of burned gases allows the in-cylinder NOx concentration to be calculated, on the basis of prompt and Zeldovich thermal mechanisms. The procedure also takes into account the NOx level in the intake charge, and is therefore suitable for engines equipped with traditional short-route EGR (Exhaust Gas Recirculation) systems, and engines equipped with SCR (Selective Catalytic Reduction) and long

  20. Specific Features of the Response of Cerium to Pulsed Actions

    Science.gov (United States)

    Atroshenko, S. A.; Zubareva, A. N.; Morozov, V. A.; Savenkov, G. G.; Utkin, A. V.

    2018-02-01

    Experimental studies of cerium at high rates and nanosecond durations of action have been performed. The isomorphic phase transition was studied upon shock compression. The spall strength of cerium has been determined. Cerium demonstrates anomalous compressibility upon dynamic loading. Stress waves dampen under action of a high-current electron beam due to the energy dissipation during fragmentation and twinning.

  1. Corrosion inhibition of 7000 series aluminium alloys with cerium diphenyl phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Julie-Anne [Department of Materials Engineering and Australian Centre of Excellence for Electromaterials Science, Wellington Rd, Monash University, Clayton, Victoria (Australia); Markley, Tracey [Department of Materials Engineering and Australian Centre of Excellence for Electromaterials Science, Wellington Rd, Monash University, Clayton, Victoria (Australia); CSIRO, Division of Materials Science and Technology, Clayton, Victoria (Australia); Forsyth, Maria, E-mail: maria.forsyth@deakin.edu.au [Department of Materials Engineering and Australian Centre of Excellence for Electromaterials Science, Wellington Rd, Monash University, Clayton, Victoria (Australia); Howlett, Patrick C. [Department of Materials Engineering and Australian Centre of Excellence for Electromaterials Science, Wellington Rd, Monash University, Clayton, Victoria (Australia); Hinton, Bruce R.W. [Department of Materials Engineering and Australian Centre of Excellence for Electromaterials Science, Wellington Rd, Monash University, Clayton, Victoria (Australia); Defence Science and Technology Organisation, Melbourne, Victoria (Australia)

    2011-02-03

    Graphical abstract: Scanning electron micrographs of microtomed surface shows pristine surface free of corrosion related 'mud cracking' inset for an inhibited AA7050 specimen when only 150 ppm Ce(dpp)3 is present in 0.1 M NaCl solution. Display Omitted Research highlights: > The thin film of hydrolysis products of Ce(dpp)3 and aluminium oxide is proposed to cause the inhibition. > The film consists of discrete Ce rich particles and a thin film over the matrix of Ce, P and Al oxides. > Discrete deposition of Ce is specifically influenced by Cu rich intermetallics. - Abstract: Cerium diphenyl phosphate (Ce(dpp){sub 3}) has previously been shown to be a strong corrosion inhibitor for aluminium-copper magnesium alloy AA2024-T3 and AA7075 in chloride solutions. Surface characterisation including SEM and ToF-SIMS coupled with electrochemical impedance spectroscopy (EIS) measurements are used to propose a mechanism of corrosion inhibition which appears to involve the formation of a complex oxide film of aluminium and cerium also incorporating the organophosphate component. The formation of a thin complex film consisting of hydrolysis products of the Ce(dpp){sub 3} compound and aluminium oxide is proposed to lead to the observed inhibition. SEM analysis shows that some intermetallics favour the creation of thicker deposits predominantly containing cerium oxide compounds.

  2. 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

  3. Prolonged Pulmonary Exposure to Diesel Exhaust Particles Exacerbates Renal Oxidative Stress, Inflammation and DNA Damage in Mice with Adenine-Induced Chronic Renal Failure.

    Science.gov (United States)

    Nemmar, Abderrahim; Karaca, Turan; Beegam, Sumaya; Yuvaraju, Priya; Yasin, Javed; Hamadi, Naserddine Kamel; Ali, Badreldin H

    2016-01-01

    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. 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. 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. Prolonged pulmonary exposure to diesel exhaust particles worsen renal oxidative stress, inflammation and DNA damage in mice with adenine-induced chronic renal failure. Our data provide biological plausibility that air

  4. 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

  5. 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

  6. 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 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...... for the study of oxidative damage induced by particulate matter. (C) 2003 Elsevier Science (USA). All rights reserved....

  7. Features of the theories of the formation of oxide films on aluminum alloys piston diesel engines with micro-arc oxidation

    Directory of Open Access Journals (Sweden)

    Skryabin M.L.

    2017-12-01

    Full Text Available The article considers one of the promising methods of surface hardening of piston aluminum alloy – microarc oxidation. Described fundamental differences from the micro-arc oxidation anodizing and similar electrochemical processes. The schemes of formation of the barrier and outer layers surface treatment in aqueous electrolytes. Shows the mechanism of formation of the interface. Considers the formation of layers with high porosity and method of exposure. Also describes the exponential dependence of the current density from the electric field in the surface film of the base metal. The role of discharges in the formation of oxide layers on the treated surface. Proposed and described features of the three main theories of formation of oxide films on the surface of the piston: physical and geometrical model of Keller; models of formation of oxide films as a colloid formations and plasma theory (theory of oxidation with the formation of plasma in the zone of oxidation. The features of formation of films in each of the models. For the model of Keller porous oxide film is a close-Packed oxide cell, having the shape of a prism. They are based on a hexagonal prism. These cells have normal orientation to the surface of the metal. In the center of the unit cell there is one season that is a channel, whose size is determined by the composition of the electrolyte, the chemical composition of the base metal and the electrical parameters of the process of oxidation. In the micro-arc oxidation process according to this model, the beginning of the formation of cells occurs with the formation of the barrier layer, passing in the porous layer and, over time, the elonga-tion of the pores, due to the constant etching electrolyte. In the theory of formation of the oxide films as kolloidnyh formations revealed that formation of pores in the film is a result of their growth. The anodic oxide is represented by a directed electric field, the alumina gel colloidal and

  8. EXAFS and XANES analysis of plutonium and cerium edges from titanate ceramics for fissile materials disposal

    International Nuclear Information System (INIS)

    Fortner, J. A.; Kropf, A. J.; Bakel, A. J.; Hash, M. C.; Aase, S. B.; Buck, E. C.; Chamerlain, D. B.

    1999-01-01

    We report x-ray absorption near edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) spectra from the plutonium L III edge and XANES from the cerium L II edge in prototype titanate ceramic hosts. The titanate ceramics studied are based upon the hafnium-pyrochlore and zirconolite mineral structures and will serve as an immobilization host for surplus fissile materials, containing as much as 10 weight % fissile plutonium and 20 weight % (natural or depleted) uranium. Three ceramic formulations were studied: one employed cerium as a ''surrogate'' element, replacing both plutonium and uranium in the ceramic matrix, another formulation contained plutonium in a ''baseline'' ceramic formulation, and a third contained plutonium in a formulation representing a high-impurity plutonium stream. The cerium XANES from the surrogate ceramic clearly indicates a mixed III-IV oxidation state for the cerium. In contrast, XANES analysis of the two plutonium-bearing ceramics shows that the plutonium is present almost entirely as Pu(IV) and occupies the calcium site in the zirconolite and pyrochlore phases. The plutonium EXAFS real-space structure shows a strong second-shell peak, clearly distinct from that of PuO 2 , with remarkably little difference in the plutonium crystal chemistry indicated between the baseline and high-impurity formulations

  9. Diesel engine performance and emission analysis using soybean ...

    African Journals Online (AJOL)

    Biodiesel presents a large potential for replacing other fossil-based fuels. Thus, the present work aimed to assess the specific fuel consumption (SFC), thermal efficiency and emissions of nitric oxide (NO) and nitrogen oxides (NOx), in a cycle diesel engine-generator set, using soybean biodiesel and diesel as fuels.

  10. Preparation and Characterization of MoO3/Al2O3 Catalyst for Oxidative Desulfurization of Diesel using H2O2: Effect of Drying Method and Mo Loading

    OpenAIRE

    Azam Akbari; Mohammadreza Omidkhah; Jafar Toufighi Darian

    2012-01-01

    The mesoporous MoO3/γ-Al2O3 catalyst was prepared by incipient wetness impregnation method aiming to investigate the effect of drying method and molybdenum content on the catalyst property and performance towards the oxidation of benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyle dibenzothiophene (4,6-DMDBT) with H2O2 for deep oxidative desulfurization of diesel fuel. The catalyst was characterized by XRD, BET, BJH and SEM method. The catalyst with 10wt.% and 1...

  11. Corrosion of Zn5Al and Zn55Al alloys with cerium, praseodymium and neodymium

    International Nuclear Information System (INIS)

    Alikhanova, S.D.

    2017-01-01

    The present work is devoted to corrosion of Zn5Al and Zn55Al alloys with cerium, praseodymium and neodymium. The purpose of present work is elaboration of optimal composition of zinc-aluminium alloys Zn5Al and Zn55Al alloyed by rare-earth metals of cerium subgroup which are used as anode covers for protection of steel from corrosion. Therefore, the regularities of change of corrosion-electrochemical properties in various corrosive mediums have been determined; processes mechanisms of high temperature oxidation of alloys in solid state have been studied; in the products of alloys oxidation their phase components have been defined and their role in the corrosion process have been revealed; the optimal compositions of zinc-aluminium alloys alloyed by rare earth metals, which are protected by two patents of the Republic of Tajikistan have been elaborated.

  12. Polymer-bound oxidovanadium(IV) and dioxidovanadium(V) complexes as catalysts for the oxidative desulfurization of model fuel diesel.

    Science.gov (United States)

    Maurya, Mannar R; Arya, Aarti; Kumar, Amit; Kuznetsov, Maxim L; Avecilla, Fernando; Costa Pessoa, João

    2010-07-19

    The Schiff base (Hfsal-dmen) derived from 3-formylsalicylic acid and N,N-dimethyl ethylenediamine has been covalently bonded to chloromethylated polystyrene to give the polymer-bound ligand, PS-Hfsal-dmen (I). Treatment of PS-Hfsal-dmen with [V(IV)O(acac)(2)] in the presence of MeOH gave the oxidovanadium(IV) complex PS-[V(IV)O(fsal-dmen)(MeO)] (1). On aerial oxidation in methanol, complex 1 was oxidized to PS-[V(V)O(2)(fsal-dmen)] (2). The corresponding neat complexes, [V(IV)O(sal-dmen)(acac)] (3) and [V(V)O(2)(sal-dmen)] (4) were similarly prepared. All these complexes are characterized by various spectroscopic techniques (IR, electronic, NMR, and electron paramagnetic resonance (EPR)) and thermal as well as field-emission scanning electron micrographs (FE-SEM) studies, and the molecular structures of 3 and 4 were determined by single crystal X-ray diffraction. The EPR spectrum of the polymer supported V(IV)O-complex 1 is characteristic of magnetically diluted V(IV)O-complexes, the resolved EPR pattern indicating that the V(IV)O-centers are well dispersed in the polymer matrix. A good (51)V NMR spectrum could also be measured with 4 suspended in dimethyl sulfoxide (DMSO), the chemical shift (-503 ppm) being compatible with a VO(2)(+)-center and a N,O binding set. The catalytic oxidative desulfurization of organosulfur compounds thiophene, dibenzothiophene, benzothiophene, and 2-methyl thiophene (model of fuel diesel) was carried out using complexes 1 and 2. The sulfur in model organosulfur compounds oxidizes to the corresponding sulfone in the presence of H(2)O(2). The systems 1 and 2 do not loose efficiency for sulfoxidation at least up to the third cycle of reaction, this indicating that they preserve their integrity under the conditions used. Plausible intermediates involved in these catalytic processes are established by UV-vis, EPR, (51)V NMR, and density functional theory (DFT) studies, and an outline of the mechanism is proposed. The (51)V NMR spectra

  13. Nanostructured sol-gel coatings doped with cerium nitrate as pre-treatments for AA2024-T3

    International Nuclear Information System (INIS)

    Zheludkevich, M.L.; Serra, R.; Montemor, M.F.; Yasakau, K.A.; Salvado, I.M. Miranda; Ferreira, M.G.S.

    2005-01-01

    Nanostructured hybrid sol-gel coatings doped with cerium ions were investigated in the present work as pre-treatments for the AA2024-T3 alloy. The sol-gel films have been synthesized from tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTMS) precursors. Additionally the hybrid sol was doped with zirconia nanoparticles prepared from hydrolyzed tetra-n-propoxyzirconium (TPOZ). Cerium nitrate, as corrosion inhibitor, was added into the hybrid matrix or into the oxide nanoparticles. The chemical composition and the structure of the hybrid sol-gel films were studied by XPS (X-ray photoelectron spectroscopy) and AFM (atomic force microscopy), respectively. The evolution of the corrosion protection properties of the sol-gel films was studied by EIS (electrochemical impedance spectroscopy), which can provide quantitative information on the role of the different pre-treatments. Different equivalent circuits, for different stages of the corrosion processes, were used in order to model the coating degradation. The models were supported by SEM (scanning electron microscopy) measurements. The results show that the sol-gel films containing zirconia nanoparticles present improved barrier properties. Doping the hybrid nanostructured sol-gel coatings with cerium nitrate leads to additional improvement of the corrosion protection. The zirconia particles present in the sol-gel matrix seem to act as nanoreservoirs providing a prolonged release of cerium ions. The nanostructured sol-gel films doped with cerium nitrate can be proposed as a potential candidate for substitution of the chromate pre-treatments for AA2024-T3

  14. Influence of alumina oxide nanoparticles on the performance and emissions in a methyl ester of neem oil fuelled direct injection diesel engine

    Directory of Open Access Journals (Sweden)

    Balaji Gnanasikamani

    2017-01-01

    Full Text Available The experimental investigation of the influence of Al2O3 nanoadditive on performance and emissions in a methyl ester of neem oil fueled direct injection Diesel engine is reported in this paper. The Al2O3 nanoparticles are mixed in various proportions (100 to 300 ppm with methyl ester of neem oil. The performance and emissions are tested in a single cylinder computerized, 4-stroke, stationary, water-cooled Diesel engine of 3.5 kW rated power. Results show that the nanoadditive is effective in increasing the performance and controlling the NO emissions of methyl ester of neem oil fueled Diesel engines.

  15. Cerium Titanate Nano dispersoids in Ni-base ODS Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Suk Hoon; Chun, Young-Bum; Rhee, Chang-Kyu; Jang, Jinsung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Chung, Hee-Suk [Korea Basic Science Institute, Jeonju (Korea, Republic of)

    2016-10-15

    Oxide-dispersion-strengthened (ODS) nickel-base alloys have potential for use in rather demanding elevated-temperature environments, such as aircraft turbine engines, heat exchanger of nuclear reactor. For improved high temperature performance, several ODS alloys were developed which possess good elevated temperature strength and over-temperature capacity plus excellent static oxidation resistance. The high temperature strength of ODS alloys is due to the presence of a uniform dispersion of fine, inert particles. Ceria mixed oxides have been studied because of their application potential in the formation of nanoclusters. By first principle study, it was estimated that the formation energy of the Ce-O dimer with voids in the nickel base alloy is lower than other candidates. The result suggests that the dispersion of the Ceria mixed oxides can suppress the voiding or swelling behavior of nickel base alloy during neutron irradiation. In this study, the evolution of cerium titanate nano particles was investigated using in-situ TEM. It was found that the Ce{sub 2}Ti{sub 3}O{sub 9} phase was easily formed rather than remain as CeO{sub 2} during annealing; Ti was effective to form the finer oxide particles. Ce{sub 2}Ti{sub 3}O{sub 9} is expected to do the great roll as dispersoids in Ni-base alloy, contribute to achieve the better high temperature property, high swelling resistance during neutron radiation.

  16. Features of the theories of the formation of oxide films on aluminum alloys piston diesel engines with micro-arc oxidation

    OpenAIRE

    Skryabin M.L.; Smekhova I. N.

    2017-01-01

    The article considers one of the promising methods of surface hardening of piston aluminum alloy – microarc oxidation. Described fundamental differences from the micro-arc oxidation anodizing and similar electrochemical processes. The schemes of formation of the barrier and outer layers surface treatment in aqueous electrolytes. Shows the mechanism of formation of the interface. Considers the formation of layers with high porosity and method of exposure. Also describes the exponential depende...

  17. Protective effects of Curcuma longa against neurobehavioral and neurochemical damage caused by cerium chloride in mice.

    Science.gov (United States)

    Kadri, Yamina; Nciri, Riadh; Brahmi, Noura; Saidi, Saber; Harrath, Abdel Halim; Alwasel, Saleh; Aldahmash, Waleed; El Feki, Abdelfatteh; Allagui, Mohamed Salah

    2018-05-07

    Cerium chloride (CeCl 3 ) is considered an environmental pollutant and a potent neurotoxic agent. Medicinal plants have many bioactive compounds that provide protection against damage caused by such pollutants. Curcuma longa is a bioactive compound-rich plant with very important antioxidant properties. To study the preventive and healing effects of Curcuma longa on cerium-damaged mouse brains, we intraperitoneally injected cerium chloride (CeCl 3 , 20 mg/kg BW) along with Curcuma longa extract, administrated by gavage (100 mg/kg BW), into mice for 60 days. We then examined mouse behavior, brain tissue damage, and brain oxidative stress parameters. Our results revealed a significant modification in the behavior of the CeCl 3 -treated mice. In addition, CeCl 3 induced a significant increment in lipid peroxidation, carbonyl protein (PCO), and advanced oxidation protein product levels, as well as a significant reduction in superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. Acetylcholinesterase (AChE) activity remarkably increased in the brain of CeCl 3 -treated mice. Histopathological observations confirmed these results. Curcuma longa attenuated CeCl 3 -induced oxidative stress and increased the activities of antioxidant enzymes. It also decreased AChE activity in the CeCl 3 -damaged mouse brain that was confirmed by histopathology. In conclusion, this study suggests that Curcuma longa has a neuroprotective effect against CeCl 3 -induced damage in the brain.

  18. Assessment of the abatement of acelsulfame K using cerium doped ZnO as photocatalyst

    International Nuclear Information System (INIS)

    Calza, P.; Gionco, C.; Giletta, M.; Kalaboka, M.; Sakkas, V.A.; Albanis, T.; Paganini, M.C.

    2017-01-01

    Highlights: • Hydrothermal synthesis and characterization of Ce doped ZnO. • The abatement of ACE K is assessed in ultrapure water and in river water matrix. • Demonstrated higher degradation activity than P25 under visible light. • The degradation activity is less affected in river water than for P25. - Abstract: In the present study, we investigated the possibility to abate Acesulfame K, a persistent emerging contaminant, in aqueous media using zinc oxide based materials. For this purpose, bare and Ce-doped zinc oxide was prepared via an easy and cheap hydrothermal process using different cerium salts as precursors. Their photocatalytic performance was evaluated in different media, namely ultrapure and river water under both UV–vis and visible light. Commercial TiO_2 P25 was also employed and used as a reference photocatalyst for comparison purposes. The obtained results pointed out that cerium doped zinc oxide composites exhibit higher performance than TiO_2 P25, especially under visible light and in the presence of organic matter, when the activity of the latter is greatly depressed. In particular, ZnO doped with cerium (1%) was the most effective material, and could be a promising alternative to TiO_2 P25, especially in the treatment of natural waters.

  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. Numerical investigation of soot formation and oxidation processes under large two-stroke marine diesel engine-like conditions using integrated CFD-chemical kinetics

    DEFF Research Database (Denmark)

    Pang, Kar Mun; Karvounis, Nikolas; Walther, Jens Honore

    2016-01-01

    n-heptane mechanism and a revised multi-step soot model using laser extinction measurements of diesel soot obtained at different ambient pressure levels in an optical accessible, constant volume chamber experiment. It is revealed that ignition delay times and liftoff lengths generated using the new......In this reported work, multi-dimensional computational fluid dynamics studies of diesel combustion and soot formation processes in a constant volume combustion chamber and a marine diesel engine are carried out. The key interest here is firstly to validate the coupling of a newly developed skeletal...... using the revised soot model agrees reasonably well with the measurements in terms of peak values. The numerical model is subsequently applied to investigate the flame development, soot/nitrogen monoxide formation and heat transfer in a two-stroke, low-speed uniflow-scavenged marine diesel engine...

  1. Engine performance and emissions characteristics of a diesel engine fueled with diesel-biodiesel-bioethanol emulsions

    International Nuclear Information System (INIS)

    Tan, Yie Hua; Abdullah, Mohammad Omar; Nolasco-Hipolito, Cirilo; Zauzi, Nur Syuhada Ahmad; Abdullah, Georgie Wong

    2017-01-01

    were observed to be higher in comparison to diesel, A. The CO_2 (carbon dioxide) and CO (carbon monoxide) emissions were reported to be lower than diesel oil. The effect of using emulsion fuels decreased the NOx (nitrogen oxides) emissions at medium engine speeds, i.e. approximately 30.0%. Lesser NOx emission was attributed by the reduction of cetane number of the diesel-biodiesel-bioethanol emulsion fuels’ cetane number as the amount of bioethanol increases. However, the emissions of NOx were found to increase gradually at low speed (∼1600 rpm), high load; high speed (∼2400 rpm), medium load conditions. It was found that the combustion performance and emissions of the diesel engine very much depend on the fuel, its emulsion combination types and engine operating conditions.

  2. Thrombosis, systemic and cardiac oxidative stress and DNA damage induced by pulmonary exposure to diesel exhaust particles, and the effect of nootkatone thereon.

    Science.gov (United States)

    Nemmar, Abderrahim; Al-Salam, Suhail; Beegam, Sumaya; Yuvaraju, Priya; Ali, Badreldin H

    2018-01-05

    Adverse cardiovascular effects of particulate air pollution persist even at lower concentrations than those of the current air quality limit. Therefore, identification of safe and effective measures against particles-induced cardiovascular toxicity is needed. Nootkatone is a sesquiterpenoid in grapefruit with diverse bioactivities including anti-inflammatory and antioxidant effects. However, its protective effect on the cardiovascular injury induced by diesel exhaust particles (DEP) has not been studied before. We assessed the possible protective effect of nootkatone (90 mg/kg) administered by gavage 1h before intratracheal (i.t.) instillation of DEP (30 μg/mouse). Twenty-four h following the i.t. administration of DEP various thrombotic and cardiac parameters were assessed. Nootkatone inhibited the prothrombotic effect induced by DEP in pial arterioles and venules in vivo and platelet aggregation in whole blood in vitro. Also, nootkatone prevented the shortening of activated partial thromboplastin time and prothrombin time induced by DEP. Nootkatone inhibited the increase of plasma concentration of fibrinogen, plasminogen activator inhibitor-1, interleukin-6 and lipid peroxidation induced by DEP. Immunohistochemically, hearts showed an analogous increase in glutathione and nuclear factor erythroid-derived 2-like 2 (Nrf2) expression by cardiac myocytes and endothelial cells following DEP exposure, and these effects were enhanced in mice treated with nootkatone+DEP. Likewise, heme oxygenase-1 (HO-1) was increased in mice treated with nootkatone+DEP compared with those treated with DEP or nootkatone+saline. The DNA damage caused by DEP was prevented by nootkatoone pretreatment. In conclusion, nootkatoone alleviates DEP-induced thrombogenicity and systemic and cardiac oxidative stress and DNA damage, at least partly, through Nrf2 and HO-1 activation.

  3. ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF MOBILE SOURCE EMISSIONS CONTROL DEVICES: CLEAN DIESEL TECHNOLOGIES FUEL-BORNE CATALYST WITH MITSUI/PUREARTH CATALYZED WIRE MESH FILTER

    Science.gov (United States)

    The Environmental Technology Verification report discusses the technology and performance of the Fuel-Borne Catalyst with Mitsui/PUREarth Catalyzed Wire Mesh Filter manufactured by Clean Diesel Technologies, Inc. The technology is a platinum/cerium fuel-borne catalyst in commerci...

  4. Two-phase titration of cerium(3) by permanganate

    International Nuclear Information System (INIS)

    Lazarev, A.I.; Lazareva, V.I.; Gerko, V.V.

    1986-01-01

    Reaction of cerium (3) and permanganate was investigated at a room temperature depending on PH, concentrations of pyrophosphate, cerium (3), tetraphenylphosphonium and foreign compounds. Selective method of two-phase titration determination of cerium (3) by permanganate without using silver compounds, preliminary separation of chlorides, nitrates, was developed. The method was tested using alloys based on iron, nickel, REE, copper, cobalt (S r ≤0.008). Correctness is proved with method of standard additives

  5. 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.