Science.gov

Sample records for driven advanced oxidation

  1. Decontamination of soil washing wastewater using solar driven advanced oxidation processes.

    PubMed

    Bandala, Erick R; Velasco, Yuridia; Torres, Luis G

    2008-12-30

    Decontamination of soil washing wastewater was performed using two different solar driven advanced oxidation processes (AOPs): the photo-Fenton reaction and the cobalt/peroxymonosulfate/ultraviolet (Co/PMS/UV) process. Complete sodium dodecyl sulphate (SDS), the surfactant agent used to enhance soil washing process, degradation was achieved when the Co/PMS/UV process was used. In the case of photo-Fenton reaction, almost complete SDS degradation was achieved after the use of almost four times the actual energy amount required by the Co/PMS/UV process. Initial reaction rate in the first 15min (IR15) was determined for each process in order to compare them. Highest IR15 value was determined for the Co/PMS/UV process (0.011mmol/min) followed by the photo-Fenton reaction (0.0072mmol/min) and the dark Co/PMS and Fenton processes (IR15=0.002mmol/min in both cases). Organic matter depletion in the wastewater, as the sum of surfactant and total petroleum hydrocarbons present (measured as chemical oxygen demand, COD), was also determined for both solar driven processes. It was found that, for the case of COD, the highest removal (69%) was achieved when photo-Fenton reaction was used whereas Co/PMS/UV process yielded a slightly lower removal (51%). In both cases, organic matter removal achieved was over 50%, which can be consider proper for the coupling of the tested AOPs with conventional wastewater treatment processes such as biodegradation.

  2. Recent advances in ruthenium complex-based light-driven water oxidation catalysts.

    PubMed

    Xue, Long-Xin; Meng, Ting-Ting; Yang, Wei; Wang, Ke-Zhi

    2015-11-01

    The light driven splitting of water is one of the most attractive approaches for direct conversion of solar energy into chemical energy in the future. Ruthenium complexes as the water oxidation catalysts (WOCs) and light sensitizers have attracted increasing attention, and have made a great progress. This mini-review highlights recent progress on ruthenium complex-based photochemical and photoelectrochemical water oxidation catalysts. The recent representative examples of these ruthenium complexes that are in homogeneous solution or immobilized on solid electrodes, are surveyed. In particular, special attention has been paid on the supramolecular dyads with photosensitizer and WOC being covalently hold together, and grafted onto the solid electrode. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Novel MoSe2 hierarchical microspheres for applications in visible-light-driven advanced oxidation processes.

    PubMed

    Dai, Chu; Qing, Enping; Li, Yong; Zhou, Zhaoxin; Yang, Chao; Tian, Xike; Wang, Yanxin

    2015-12-21

    Advanced oxidation processes as a green technology have been adopted by combining the semiconductor catalyst MoSe2 with H2O2 under visible radiation. And novel three-dimensional self-assembled molybdenum diselenide (MoSe2) hierarchical microspheres from nanosheets were produced by using organic, selenium cyanoacetic acid sodium (NCSeCH2COONa) as the source of Se. The obtained products possess good crystallinity and present hierarchical structures with the average diameter of 1 μm. The band gap of MoSe2 microspheres is 1.68 eV and they present excellent photocatalytic activity under visible light irradiation in the MoSe2-H2O2 system. This effective photocatalytic mechanism was investigated in this study and can be attributed to visible-light-driven advanced oxidation processes.

  4. Novel MoSe2 hierarchical microspheres for applications in visible-light-driven advanced oxidation processes

    NASA Astrophysics Data System (ADS)

    Dai, Chu; Qing, Enping; Li, Yong; Zhou, Zhaoxin; Yang, Chao; Tian, Xike; Wang, Yanxin

    2015-11-01

    Advanced oxidation processes as a green technology have been adopted by combining the semiconductor catalyst MoSe2 with H2O2 under visible radiation. And novel three-dimensional self-assembled molybdenum diselenide (MoSe2) hierarchical microspheres from nanosheets were produced by using organic, selenium cyanoacetic acid sodium (NCSeCH2COONa) as the source of Se. The obtained products possess good crystallinity and present hierarchical structures with the average diameter of 1 μm. The band gap of MoSe2 microspheres is 1.68 eV and they present excellent photocatalytic activity under visible light irradiation in the MoSe2-H2O2 system. This effective photocatalytic mechanism was investigated in this study and can be attributed to visible-light-driven advanced oxidation processes.

  5. Fully solar-driven thermo- and electrochemistry for advanced oxidation processes (STEP-AOPs) of 2-nitrophenol wastewater.

    PubMed

    Nie, Chunhong; Shao, Nan; Wang, Baohui; Yuan, Dandan; Sui, Xin; Wu, Hongjun

    2016-07-01

    The STEP (Solar Thermal Electrochemical Process) for Advanced Oxidation Processes (AOPs, combined to STEP-AOPs), fully driven by solar energy without the input of any other forms of energy and chemicals, is introduced and demonstrated from the theory to experiments. Exemplified by the persistent organic pollutant 2-nitrophenol in water, the fundamental model and practical system are exhibited for the STEP-AOPs to efficiently transform 2-nitrophenol into carbon dioxide, water, and the other substances. The results show that the STEP-AOPs system performs more effectively than classical AOPs in terms of the thermodynamics and kinetics of pollutant oxidation. Due to the combination of solar thermochemical reactions with electrochemistry, the STEP-AOPs system allows the requisite electrolysis voltage of 2-nitrophenol to be experimentally decreased from 1.00 V to 0.84 V, and the response current increases from 18 mA to 40 mA. STEP-AOPs also greatly improve the kinetics of the oxidation at 30 °C and 80 °C. As a result, the removal rate of 2-nitrophenol after 1 h increased from 19.50% at 30 °C to 32.70% at 80 °C at constant 1.90 V. Mechanistic analysis reveals that the oxidation pathway is favorably changed because of thermal effects. The tracking of the reaction displayed that benzenediol and hydroquinone are initial products, with maleic acid and formic acid as sequential carboxylic acid products, and carbon dioxide as the final product. The theory and experiments on STEP-AOPs system exemplified by the oxidation of 2-nitrophenol provide a broad basis for extension of the STEP and AOPs for rapid and efficient treatment of organic wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Advances in Electrically Driven Thermal Management

    NASA Technical Reports Server (NTRS)

    Didion, Jeffrey R.

    2017-01-01

    Electrically Driven Thermal Management is a vibrant technology development initiative incorporating ISS based technology demonstrations, development of innovative fluid management techniques and fundamental research efforts. The program emphasizes high temperature high heat flux thermal management required for future generations of RF electronics and power electronic devices. This presentation reviews i.) preliminary results from the Electrohydrodynamic (EHD) Long Term Flight Demonstration launched on STP-H5 payload in February 2017 ii.) advances in liquid phase flow distribution control iii.) development of the Electrically Driven Liquid Film Boiling Experiment under the NASA Microgravity Fluid Physics Program.

  7. ADVANCED OXIDATION PROCESS

    SciTech Connect

    Dr. Colin P. Horwitz; Dr. Terrence J. Collins

    2003-11-04

    The removal of recalcitrant sulfur species, dibenzothiophene and its derivatives, from automotive fuels is an integral component in the development of cleaner burning and more efficient automobile engines. Oxidative desulfurization (ODS) wherein the dibenzothiophene derivative is converted to its corresponding sulfoxide and sulfone is an attractive approach to sulfur removal because the oxidized species are easily extracted or precipitated and filtered from the hydrocarbon phase. Fe-TAML{reg_sign} activators of hydrogen peroxide (TAML is Tetra-Amido-Macrocyclic-Ligand) catalytically convert dibenzothiophene and its derivatives rapidly and effectively at moderate temperatures (50-60 C) and ambient pressure to the corresponding sulfoxides and sulfones. The oxidation process can be performed in both aqueous systems containing alcohols such as methanol, ethanol, or t-butanol, and in a two-phase hydrocarbon/aqueous system containing tert-butanol or acetonitrile. In the biphasic system, essentially complete conversion of the DBT to its oxidized products can be achieved using slightly longer reaction times than in homogeneous solution. Among the key features of the technology are the mild reaction conditions, the very high selectivity where no over oxidation of the sulfur compounds occurs, the near stoichiometric use of hydrogen peroxide, the apparent lack of degradation of sensitive fuel components, and the ease of separation of oxidized products.

  8. Light-driven water oxidation for solar fuels

    PubMed Central

    Young, Karin J.; Martini, Lauren A.; Milot, Rebecca L.; III, Robert C. Snoeberger; Batista, Victor S.; Schmuttenmaer, Charles A.; Crabtree, Robert H.; Brudvig, Gary W.

    2014-01-01

    Light-driven water oxidation is an essential step for conversion of sunlight into storable chemical fuels. Fujishima and Honda reported the first example of photoelectrochemical water oxidation in 1972. In their system, TiO2 was irradiated with ultraviolet light, producing oxygen at the anode and hydrogen at a platinum cathode. Inspired by this system, more recent work has focused on functionalizing nanoporous TiO2 or other semiconductor surfaces with molecular adsorbates, including chromophores and catalysts that absorb visible light and generate electricity (i.e., dye-sensitized solar cells) or trigger water oxidation at low overpotentials (i.e., photocatalytic cells). The physics involved in harnessing multiple photochemical events for multielectron reactions, as required in the four-electron water oxidation process, has been the subject of much experimental and computational study. In spite of significant advances with regard to individual components, the development of highly efficient photocatalytic cells for solar water splitting remains an outstanding challenge. This article reviews recent progress in the field with emphasis on water-oxidation photoanodes inspired by the design of functionalized thin film semiconductors of typical dye-sensitized solar cells. PMID:25364029

  9. HANDBOOK ON ADVANCED PHOTOCHEMICAL OXIDATION ...

    EPA Pesticide Factsheets

    This handbook summarizes commercial-scale system performance and cost data for advanced photochemical oxidation (APO) treatment of contaminated water, air, and solids. Similar information from pilot- and bench-scale evaluations of APO processes is also included to supplement the commercial-scale data. Performance and cost data is summarized for various APO processes, including vacuum ultraviolet (VUV) photolysis, ultraviolet (UV)/oxidation, photo-Fenton, and dye- or semiconductor-sensitized APO processes. This handbook is intended to assist engineering practitioners in evaluating the applicability of APO processes and in selecting one or more such processes for site-specific evaluation.APO has been shown to be effective in treating contaminated water and air. Regarding contaminated water treatment, UV/oxidation has been evaluated for the most contaminants, while VUV photolysis has been evaluated for the fewest. Regarding contaminated air treatment, the sensitized APO processes have been evaluated for the most contaminants, while VUV photolysis has been evaluated for the fewest.APO processes for treating contaminated solids generally involve treatment of contaminated slurry or leachate generated using an extraction process such as soil washing. APO has been shown to be effective in treating contaminated solids, primarily at the bench-scale level. Information

  10. Advanced motor driven clamped borehole seismic receiver

    DOEpatents

    Engler, Bruce P.; Sleefe, Gerard E.; Striker, Richard P.

    1993-01-01

    A borehole seismic tool including a borehole clamp which only moves perpendicular to the borehole. The clamp is driven by an electric motor, via a right angle drive. When used as a seismic receiver, the tool has a three part housing, two of which are hermetically sealed. Accelerometers or geophones are mounted in one hermetically sealed part, the electric meter in the other hermetically sealed part, and the clamp and right angle drive in the third part. Preferably the tool includes cable connectors at both ends. Optionally a shear plate can be added to the clamp to extend the range of the tool.

  11. Advanced motor driven clamped borehole seismic receiver

    DOEpatents

    Engler, B.P.; Sleefe, G.E.; Striker, R.P.

    1993-02-23

    A borehole seismic tool is described including a borehole clamp which only moves perpendicular to the borehole. The clamp is driven by an electric motor, via a right angle drive. When used as a seismic receiver, the tool has a three part housing, two of which are hermetically sealed. Accelerometers or geophones are mounted in one hermetically sealed part, the electric motor in the other hermetically sealed part, and the clamp and right angle drive in the third part. Preferably the tool includes cable connectors at both ends. Optionally a shear plate can be added to the clamp to extend the range of the tool.

  12. Advanced oxidation scanning probe lithography.

    PubMed

    Ryu, Yu K; Garcia, Ricardo

    2017-04-07

    Force microscopy enables a variety of approaches to manipulate and/or modify surfaces. Few of those methods have evolved into advanced probe-based lithographies. Oxidation scanning probe lithography (o-SPL) is the only lithography that enables the direct and resist-less nanoscale patterning of a large variety of materials, from metals to semiconductors; from self-assembled monolayers to biomolecules. Oxidation SPL has also been applied to develop sophisticated electronic and nanomechanical devices such as quantum dots, quantum point contacts, nanowire transistors or mechanical resonators. Here, we review the principles, instrumentation aspects and some device applications of o-SPL. Our focus is to provide a balanced view of the method that introduces the key steps in its evolution, provides some detailed explanations on its fundamentals and presents current trends and applications. To illustrate the capabilities and potential of o-SPL as an alternative lithography we have favored the most recent and updated contributions in nanopatterning and device fabrication.

  13. Advanced oxidation scanning probe lithography

    NASA Astrophysics Data System (ADS)

    Ryu, Yu K.; Garcia, Ricardo

    2017-04-01

    Force microscopy enables a variety of approaches to manipulate and/or modify surfaces. Few of those methods have evolved into advanced probe-based lithographies. Oxidation scanning probe lithography (o-SPL) is the only lithography that enables the direct and resist-less nanoscale patterning of a large variety of materials, from metals to semiconductors; from self-assembled monolayers to biomolecules. Oxidation SPL has also been applied to develop sophisticated electronic and nanomechanical devices such as quantum dots, quantum point contacts, nanowire transistors or mechanical resonators. Here, we review the principles, instrumentation aspects and some device applications of o-SPL. Our focus is to provide a balanced view of the method that introduces the key steps in its evolution, provides some detailed explanations on its fundamentals and presents current trends and applications. To illustrate the capabilities and potential of o-SPL as an alternative lithography we have favored the most recent and updated contributions in nanopatterning and device fabrication.

  14. Recent advances in laser-driven neutron sources

    NASA Astrophysics Data System (ADS)

    Alejo, A.; Ahmed, H.; Green, A.; Mirfayzi, S. R.; Borghesi, M.; Kar, S.

    2016-11-01

    Due to the limited number and high cost of large-scale neutron facilities, there has been a growing interest in compact accelerator-driven sources. In this context, several potential schemes of laser-driven neutron sources are being intensively studied employing laser-accelerated electron and ion beams. In addition to the potential of delivering neutron beams with high brilliance, directionality and ultra-short burst duration, a laser-driven neutron source would offer further advantages in terms of cost-effectiveness, compactness and radiation confinement by closed-coupled experiments. Some of the recent advances in this field are discussed, showing improvements in the directionality and flux of the laser-driven neutron beams.

  15. Oxide driven strength evolution of silicon surfaces

    DOE PAGES

    Grutzik, Scott J.; Milosevic, Erik; Boyce, Brad L.; ...

    2015-11-19

    Previous experiments have shown a link between oxidation and strength changes in single crystal silicon nanostructures but provided no clues as to the mechanisms leading to this relationship. Using atomic force microscope-based fracture strength experiments, molecular dynamics modeling, and measurement of oxide development with angle resolved x-ray spectroscopy we study the evolution of strength of silicon (111) surfaces as they oxidize and with fully developed oxide layers. We find that strength drops with partial oxidation but recovers when a fully developed oxide is formed and that surfaces intentionally oxidized from the start maintain their high initial strengths. MD simulations showmore » that strength decreases with the height of atomic layer steps on the surface. These results are corroborated by a completely separate line of testing using micro-scale, polysilicon devices, and the slack chain method in which strength recovers over a long period of exposure to the atmosphere. Lastly, combining our results with insights from prior experiments we conclude that previously described strength decrease is a result of oxidation induced roughening of an initially flat silicon (1 1 1) surface and that this effect is transient, a result consistent with the observation that surfaces flatten upon full oxidation.« less

  16. Oxide driven strength evolution of silicon surfaces

    SciTech Connect

    Grutzik, Scott J.; Zehnder, Alan T.; Milosevic, Erik; Boyce, Brad L.

    2015-11-21

    Previous experiments have shown a link between oxidation and strength changes in single crystal silicon nanostructures but provided no clues as to the mechanisms leading to this relationship. Using atomic force microscope-based fracture strength experiments, molecular dynamics modeling, and measurement of oxide development with angle resolved x-ray spectroscopy we study the evolution of strength of silicon (111) surfaces as they oxidize and with fully developed oxide layers. We find that strength drops with partial oxidation but recovers when a fully developed oxide is formed and that surfaces intentionally oxidized from the start maintain their high initial strengths. MD simulations show that strength decreases with the height of atomic layer steps on the surface. These results are corroborated by a completely separate line of testing using micro-scale, polysilicon devices, and the slack chain method in which strength recovers over a long period of exposure to the atmosphere. Combining our results with insights from prior experiments we conclude that previously described strength decrease is a result of oxidation induced roughening of an initially flat silicon (1 1 1) surface and that this effect is transient, a result consistent with the observation that surfaces flatten upon full oxidation.

  17. Oxide driven strength evolution of silicon surfaces

    SciTech Connect

    Grutzik, Scott J.; Milosevic, Erik; Boyce, Brad L.; Zehnder, Alan T.

    2015-11-19

    Previous experiments have shown a link between oxidation and strength changes in single crystal silicon nanostructures but provided no clues as to the mechanisms leading to this relationship. Using atomic force microscope-based fracture strength experiments, molecular dynamics modeling, and measurement of oxide development with angle resolved x-ray spectroscopy we study the evolution of strength of silicon (111) surfaces as they oxidize and with fully developed oxide layers. We find that strength drops with partial oxidation but recovers when a fully developed oxide is formed and that surfaces intentionally oxidized from the start maintain their high initial strengths. MD simulations show that strength decreases with the height of atomic layer steps on the surface. These results are corroborated by a completely separate line of testing using micro-scale, polysilicon devices, and the slack chain method in which strength recovers over a long period of exposure to the atmosphere. Lastly, combining our results with insights from prior experiments we conclude that previously described strength decrease is a result of oxidation induced roughening of an initially flat silicon (1 1 1) surface and that this effect is transient, a result consistent with the observation that surfaces flatten upon full oxidation.

  18. Advances in pulsed-power-driven radiography system design.

    SciTech Connect

    Portillo, Salvador; Hinshelwood, David D.; Rovang, Dean Curtis; Cordova, Steve Ray; Oliver, Bryan Velten; Weber, Bruce V.; Welch, Dale Robert; Shelton, Bradley Allen; Sceiford, Matthew E.; Cooperstein, Gerald; Gignac, Raymond Edward; Puetz, Elizabeth A.; Rose, David Vincent; Barker, Dennis L.; Van De Valde, David M.; Droemer, Darryl W.; Wilkins, Frank Lee; Molina, Isidro; Jaramillo, Deanna M.; Swanekamp, Stephen Brian; Commisso, Robert J.; Bailey, Vernon Leslie; Maenchen, John Eric; Johnson, David Lee; Griffin, Fawn A.; Hahn, Kelly Denise; Smith, Ian

    2004-07-01

    Flash x-ray radiography has undergone a transformation in recent years with the resurgence of interest in compact, high intensity pulsed-power-driven electron beam sources. The radiographic requirements and the choice of a consistent x-ray source determine the accelerator parameters, which can be met by demonstrated Induction Voltage Adder technologies. This paper reviews the state of the art and the recent advances which have improved performance by over an order of magnitude in beam brightness and radiographic utility.

  19. Oxidation of advanced steam turbine alloys

    SciTech Connect

    Holcomb, G.R.; Covino, B.S., Jr.; Bullard, S.J.; Ziomek-Moroz, M.

    2006-03-01

    Advanced or ultra supercritical (USC) steam power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections.

  20. Advanced metal oxide varistor concepts

    NASA Astrophysics Data System (ADS)

    Philipp, H. R.; Mahan, G. D.; Levinson, L. M.

    1984-07-01

    Zinc oxide varistors are ZnO-based ceramic semiconductor devices with highly nonlinear current-voltage characteristics similar to back-to-back Zener diodes but with much greater current, voltage, and energy-handling capabilities. Zinc oxide varistors have proven useful in a variety of applications, particularly as high-quality voltage suppression devices for the protection of ac and dc electric power transmission systems against the effects of transient overvoltages due to switching surges and lightning strikes. Simple varistor systems that use Bi or Pr as the varistor-forming additive and Co or Mn as the varistor-performance ingredient were studied. Commercial varistor materials generally use Bi as the varistor-forming ingredient, and the sintering process in such material probably proceeds in the liquid phase. Varistor materials that use Pr as the varistor-forming ingredient are also produced commercially.

  1. Oxidation of alloys for advanced steam turbines

    SciTech Connect

    Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Ziomek-Moroz, M.; Alman, David E.

    2005-01-01

    Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections.

  2. Oxidation-driven surface dynamics on NiAl(100)

    PubMed Central

    Qin, Hailang; Chen, Xidong; Li, Liang; Sutter, Peter W.; Zhou, Guangwen

    2015-01-01

    Atomic steps, a defect common to all crystal surfaces, can play an important role in many physical and chemical processes. However, attempts to predict surface dynamics under nonequilibrium conditions are usually frustrated by poor knowledge of the atomic processes of surface motion arising from mass transport from/to surface steps. Using low-energy electron microscopy that spatially and temporally resolves oxide film growth during the oxidation of NiAl(100) we demonstrate that surface steps are impermeable to oxide film growth. The advancement of the oxide occurs exclusively on the same terrace and requires the coordinated migration of surface steps. The resulting piling up of surface steps ahead of the oxide growth front progressively impedes the oxide growth. This process is reversed during oxide decomposition. The migration of the substrate steps is found to be a surface-step version of the well-known Hele-Shaw problem, governed by detachment (attachment) of Al atoms at step edges induced by the oxide growth (decomposition). By comparing with the oxidation of NiAl(110) that exhibits unimpeded oxide film growth over substrate steps we suggest that whenever steps are the source of atoms used for oxide growth they limit the oxidation process; when atoms are supplied from the bulk, the oxidation rate is not limited by the motion of surface steps. PMID:25548155

  3. Oxidation-driven surface dynamics on NiAl(100)

    DOE PAGES

    Qin, Hailang; Chen, Xidong; Li, Liang; ...

    2014-12-29

    Atomic steps, a defect common to all crystal surfaces, can play an important role in many physical and chemical processes. However, attempts to predict surface dynamics under nonequilibrium conditions are usually frustrated by poor knowledge of the atomic processes of surface motion arising from mass transport from/to surface steps. Using low-energy electron microscopy that spatially and temporally resolves oxide film growth during the oxidation of NiAl(100) we demonstrate that surface steps are impermeable to oxide film growth. The advancement of the oxide occurs exclusively on the same terrace and requires the coordinated migration of surface steps. The resulting piling upmore » of surface steps ahead of the oxide growth front progressively impedes the oxide growth. This process is reversed during oxide decomposition. The migration of the substrate steps is found to be a surface-step version of the well-known Hele-Shaw problem, governed by detachment (attachment) of Al atoms at step edges induced by the oxide growth (decomposition). As a result, by comparing with the oxidation of NiAl(110) that exhibits unimpeded oxide film growth over substrate steps, we suggest that whenever steps are the source of atoms used for oxide growth they limit the oxidation process; when atoms are supplied from the bulk, the oxidation rate is not limited by the motion of surface steps.« less

  4. Oxidation-driven surface dynamics on NiAl(100)

    SciTech Connect

    Qin, Hailang; Chen, Xidong; Li, Liang; Sutter, Peter W.; Zhou, Guangwen

    2014-12-29

    Atomic steps, a defect common to all crystal surfaces, can play an important role in many physical and chemical processes. However, attempts to predict surface dynamics under nonequilibrium conditions are usually frustrated by poor knowledge of the atomic processes of surface motion arising from mass transport from/to surface steps. Using low-energy electron microscopy that spatially and temporally resolves oxide film growth during the oxidation of NiAl(100) we demonstrate that surface steps are impermeable to oxide film growth. The advancement of the oxide occurs exclusively on the same terrace and requires the coordinated migration of surface steps. The resulting piling up of surface steps ahead of the oxide growth front progressively impedes the oxide growth. This process is reversed during oxide decomposition. The migration of the substrate steps is found to be a surface-step version of the well-known Hele-Shaw problem, governed by detachment (attachment) of Al atoms at step edges induced by the oxide growth (decomposition). As a result, by comparing with the oxidation of NiAl(110) that exhibits unimpeded oxide film growth over substrate steps, we suggest that whenever steps are the source of atoms used for oxide growth they limit the oxidation process; when atoms are supplied from the bulk, the oxidation rate is not limited by the motion of surface steps.

  5. Oxidation-driven surface dynamics on NiAl(100)

    NASA Astrophysics Data System (ADS)

    Qin, Hailang; Chen, Xidong; Li, Liang; Sutter, Peter W.; Zhou, Guangwen

    2015-01-01

    Atomic steps, a defect common to all crystal surfaces, can play an important role in many physical and chemical processes. However, attempts to predict surface dynamics under nonequilibrium conditions are usually frustrated by poor knowledge of the atomic processes of surface motion arising from mass transport from/to surface steps. Using low-energy electron microscopy that spatially and temporally resolves oxide film growth during the oxidation of NiAl(100) we demonstrate that surface steps are impermeable to oxide film growth. The advancement of the oxide occurs exclusively on the same terrace and requires the coordinated migration of surface steps. The resulting piling up of surface steps ahead of the oxide growth front progressively impedes the oxide growth. This process is reversed during oxide decomposition. The migration of the substrate steps is found to be a surface-step version of the well-known Hele-Shaw problem, governed by detachment (attachment) of Al atoms at step edges induced by the oxide growth (decomposition). By comparing with the oxidation of NiAl(110) that exhibits unimpeded oxide film growth over substrate steps we suggest that whenever steps are the source of atoms used for oxide growth they limit the oxidation process; when atoms are supplied from the bulk, the oxidation rate is not limited by the motion of surface steps.

  6. Charge transfer driven emergent phenomena in oxide heterostructures

    NASA Astrophysics Data System (ADS)

    Chen, Hanghui; Millis, Andrew

    2017-06-01

    Complex oxides exhibit many intriguing phenomena, including metal-insulator transition, ferroelectricity/multiferroicity, colossal magnetoresistance and high transition temperature superconductivity. Advances in epitaxial thin film growth techniques enable us to combine different complex oxides with atomic precision and form an oxide heterostructure. Recent theoretical and experimental work has shown that charge transfer across oxide interfaces generally occurs and leads to a great diversity of emergent interfacial properties which are not exhibited by bulk constituents. In this report, we review mechanisms and physical consequence of charge transfer across interfaces in oxide heterostructures. Both theoretical proposals and experimental measurements of various oxide heterostructures are discussed and compared. We also review the theoretical methods that are used to calculate charge transfer across oxide interfaces and discuss the success and challenges in theory. Finally, we present a summary and perspectives for future research.

  7. HANDBOOK ON ADVANCED PHOTOCHEMICAL OXIDATION PROCESSES

    EPA Science Inventory

    This handbook summarizes commercial-scale system performance and cost data for advanced photochemical oxidation (APO) treatment of contaminated water, air, and solids. Similar information from pilot- and bench-scale evaluations of APO processes is also included to supplement the...

  8. HANDBOOK ON ADVANCED NONPHOTOCHEMICAL OXIDATION PROCESSES

    EPA Science Inventory

    The purpose of this handbook is to summarize commercial-scale system performance and cost data for advanced nonphotochemical oxidation (ANPO) treatment of contaminated water, air, and soil. Similar information from pilot-and bench-scale evaluations of ANPO processes is also inclu...

  9. HANDBOOK ON ADVANCED NONPHOTOCHEMICAL OXIDATION PROCESSES

    EPA Science Inventory

    The purpose of this handbook is to summarize commercial-scale system performance and cost data for advanced nonphotochemical oxidation (ANPO) treatment of contaminated water, air, and soil. Similar information from pilot-and bench-scale evaluations of ANPO processes is also inclu...

  10. HANDBOOK ON ADVANCED PHOTOCHEMICAL OXIDATION PROCESSES

    EPA Science Inventory

    This handbook summarizes commercial-scale system performance and cost data for advanced photochemical oxidation (APO) treatment of contaminated water, air, and solids. Similar information from pilot- and bench-scale evaluations of APO processes is also included to supplement the...

  11. Recent advances in oxidative valorization of lignin

    DOE PAGES

    Ma, Ruoshui; Guo, Mond; Zhang, Xiao

    2017-07-21

    Lignin, an aromatic macromolecule synthesized by all higher plants, is one of the most intriguing natural materials for utilization across a wide range of applications. Depolymerization and fragmentation of lignin into small chemicals constituents which can either replace current market products or be used building blocks for new material synthesis is a focus of current lignin valorization strategies. And among the variety of lignin degradation chemistries, catalytic oxidation of lignin presents an energy efficient means of lignin depolymerization and generating selective reaction products. Our review provides a summary of the recent advancements in oxidative lignin valorization couched in a discussionmore » on how these chemistries may contribute to the degradation of the lignin macromolecule through three major approaches: 1) inter-unit linkages cleavage; 2) propanyl side-chain oxidative modification; and 3) oxidation of the aromatic ring and ring cleavage reactions.« less

  12. Degradation of formaldehyde by advanced oxidation processes.

    PubMed

    Guimarães, José Roberto; Farah, Carolina Rittes Turato; Maniero, Milena Guedes; Fadini, Pedro Sérgio

    2012-09-30

    The degradation of formaldehyde in an aqueous solution (400 mg L(-1)) was studied using photolysis, peroxidation and advanced oxidation processes (UV/H(2)O(2), Fenton and photo-Fenton). Photolysis was the only process tested that did not reduce formaldehyde concentration; however, only advanced oxidation processes (AOPs) significantly decreased dissolved organic carbon (DOC). UV/H(2)O(2) and photo-Fenton AOPs were used to degrade formaldehyde at the highest concentrations (1200-12,000 mg L(-1)); the processes were able to reduce CH(2)O by 98% and DOC by 65%. Peroxidation with ultraviolet light (UV/H(2)O(2)) improved the efficiency of treatment of effluent from an anatomy laboratory. The effluent's CH(2)O content was reduced by 91%, DOC by 48%, COD by 46% and BOD by 53% in 420 min of testing.

  13. Advanced oxidation process sanitization of eggshell surfaces.

    PubMed

    Gottselig, Steven M; Dunn-Horrocks, Sadie L; Woodring, Kristy S; Coufal, Craig D; Duong, Tri

    2016-06-01

    The microbial quality of eggs entering the hatchery represents an important critical control point for biosecurity and pathogen reduction programs in integrated poultry production. The development of safe and effective interventions to reduce microbial contamination on the surface of eggs will be important to improve the overall productivity and microbial food safety of poultry and poultry products. The hydrogen peroxide (H2O2) and ultraviolet (UV) light advanced oxidation process is a potentially important alternative to traditional sanitizers and disinfectants for egg sanitation. The H2O2/UV advanced oxidation process was demonstrated previously to be effective in reducing surface microbial contamination on eggs. In this study, we evaluated treatment conditions affecting the efficacy of H2O2/UV advanced oxidation in order to identify operational parameters for the practical application of this technology in egg sanitation. The effect of the number of application cycles, UV intensity, duration of UV exposure, and egg rotation on the recovery of total aerobic bacteria from the surface of eggs was evaluated. Of the conditions evaluated, we determined that reduction of total aerobic bacteria from naturally contaminated eggs was optimized when eggs were sanitized using 2 repeated application cycles with 5 s exposure to 14 mW cm(-2) UV light, and that rotation of the eggs between application cycles was unnecessary. Additionally, using these optimized conditions, the H2O2/UV process reduced Salmonella by greater than 5 log10 cfu egg(-1) on the surface of experimentally contaminated eggs. This study demonstrates the potential for practical application of the H2O2/UV advanced oxidation process in egg sanitation and its effectiveness in reducing Salmonella on eggshell surfaces.

  14. Novel imazethapyr detoxification applying advanced oxidation processes.

    PubMed

    Stathis, Ioannis; Hela, Dimitra G; Scrano, Laura; Lelario, Filomena; Emanuele, Lucia; Bufo, Sabino A

    2011-01-01

    Different degradation methods have been applied to assess the suitability of advanced oxidation process (AOPs) to promote mineralization of imazethapyr [(RS)-5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid], a widely used imidazolinone class herbicide, the persistence of which has been demonstrated in surface and ground waters destined to human uses. Independent of the oxidation process assessed, the decomposition of imazethapyr always followed a pseudo-first order kinetic. The direct UV-irradiation (UV) of the herbicide as well as its oxidation with ozone (O₃), and hydrogen peroxide tied to UV-irradiation (H₂O₂/UV) were sufficiently slow to permit the identification of intermediate products, the formation pathway of which has been proposed. Ozonation joined to UV-irradiation (O₃/UV), ozonation joined to titanium dioxide photo-catalysis (TiO₂/UV+O₃), sole photo-catalysis (TiO₂/UV), and photo-catalysis reinforced with hydrogen peroxide-oxidation (TiO₂/UV+H₂O₂) were characterized by a faster degradation and rapid formation of a lot of small molecules, which were quickly degraded to complete mineralization. The most effective oxidation methods were those using titanium dioxide photo-catalysis enhanced either by ozonation or hydrogen peroxide. Most of all, these last processes were useful to avoid the development of dangerous by-products.

  15. Plasmon-enhanced light-driven water oxidation by a dye-sensitized photoanode.

    PubMed

    Wang, Degao; Sherman, Benjamin D; Farnum, Byron H; Sheridan, Matthew V; Marquard, Seth L; Eberhart, Michael S; Dares, Christopher J; Meyer, Thomas J

    2017-09-12

    Dye-sensitized photoelectrosynthesis cells (DSPECs) provide a flexible approach for solar water splitting based on the integration of molecular light absorption and catalysis on oxide electrodes. Recent advances in this area, including the use of core/shell oxide interfacial structures and surface stabilization by atomic layer deposition, have led to improved charge-separation lifetimes and the ability to obtain substantially improved photocurrent densities. Here, we investigate the introduction of Ag nanoparticles into the core/shell structure and report that they greatly enhance light-driven water oxidation at a DSPEC photoanode. Under 1-sun illumination, Ag nanoparticle electrodes achieved high photocurrent densities, surpassing 2 mA cm(-2) with an incident photon-to-current efficiency of 31.8% under 450-nm illumination.

  16. Induced effects of advanced oxidation processes.

    PubMed

    Liu, Peng; Li, Chaolin; Zhao, Zhuanjun; Lu, Gang; Cui, Haibo; Zhang, Wenfang

    2014-02-07

    Hazardous organic wastes from industrial, military, and commercial activities represent one of the greatest challenges to human beings. Advanced oxidation processes (AOPs) are alternatives to the degradation of those organic wastes. However, the knowledge about the exact mechanisms of AOPs is still incomplete. Here we report a phenomenon in the AOPs: induced effects, which is a common property of combustion reaction. Through analysis EDTA oxidation processes by Fenton and UV-Fenton system, the results indicate that, just like combustion, AOPs are typical induction reactions. One most compelling example is that pre-feeding easily oxidizable organic matter can promote the oxidation of refractory organic compound when it was treated by AOPs. Connecting AOPs to combustion, it is possible to achieve some helpful enlightenment from combustion to analyze, predict and understand AOPs. In addition, we assume that maybe other oxidation reactions also have induced effects, such as corrosion, aging and passivation. Muchmore research is necessary to reveal the possibilities of induced effects in those fields.

  17. Induced effects of advanced oxidation processes

    NASA Astrophysics Data System (ADS)

    Liu, Peng; Li, Chaolin; Zhao, Zhuanjun; Lu, Gang; Cui, Haibo; Zhang, Wenfang

    2014-02-01

    Hazardous organic wastes from industrial, military, and commercial activities represent one of the greatest challenges to human beings. Advanced oxidation processes (AOPs) are alternatives to the degradation of those organic wastes. However, the knowledge about the exact mechanisms of AOPs is still incomplete. Here we report a phenomenon in the AOPs: induced effects, which is a common property of combustion reaction. Through analysis EDTA oxidation processes by Fenton and UV-Fenton system, the results indicate that, just like combustion, AOPs are typical induction reactions. One most compelling example is that pre-feeding easily oxidizable organic matter can promote the oxidation of refractory organic compound when it was treated by AOPs. Connecting AOPs to combustion, it is possible to achieve some helpful enlightenment from combustion to analyze, predict and understand AOPs. In addition, we assume that maybe other oxidation reactions also have induced effects, such as corrosion, aging and passivation. Muchmore research is necessary to reveal the possibilities of induced effects in those fields.

  18. A molecular light-driven water oxidation catalyst.

    PubMed

    Kaveevivitchai, Nattawut; Chitta, Raghu; Zong, Ruifa; El Ojaimi, Maya; Thummel, Randolph P

    2012-07-04

    Two mononuclear Ru(II) complexes, [Ru(ttbt)(pynap)(I)]I and [Ru(tpy)(Mepy)(2)(I)]I (tpy = 2,2';6,2"-terpyridine; ttbt = 4,4',4"-tri-tert-butyltpy; pynap = 2-(pyrid-2'-yl)-1,8-naphthyridine; and Mepy = 4-methylpyridine), are effective catalysts for the oxidation of water. This oxidation can be driven by a blue (λ(max) = 472 nm) LED light source using [Ru(bpy)(3)]Cl(2) (bpy = 2,2'-bipyridine) as the photosensitizer. Sodium persulfate acts as a sacrificial electron acceptor to oxidize the photosensitizer that in turn drives the catalysis. The presence of all four components, light, photosensitizer, sodium persulfate, and catalyst, are required for water oxidation. A dyad assembly has been prepared using a pyrazine-based linker to join a photosensitizer and catalyst moiety. Irradiation of this intramolecular system with blue light produces oxygen with a higher turnover number than the analogous intermolecular component system under the same conditions.

  19. Visible-Light-Driven Water Oxidation by a Molecular Manganese Vanadium Oxide Cluster.

    PubMed

    Schwarz, Benjamin; Forster, Johannes; Goetz, McKenna K; Yücel, Duygu; Berger, Claudia; Jacob, Timo; Streb, Carsten

    2016-05-17

    Photosynthetic water oxidation in plants occurs at an inorganic calcium manganese oxo cluster, which is known as the oxygen evolving complex (OEC), in photosystem II. Herein, we report a synthetic OEC model based on a molecular manganese vanadium oxide cluster, [Mn4 V4 O17 (OAc)3 ](3-) . The compound is based on a [Mn4 O4 ](6+) cubane core, which catalyzes the homogeneous, visible-light-driven oxidation of water to molecular oxygen and is stabilized by a tripodal [V4 O13 ](6-) polyoxovanadate and three acetate ligands. When combined with the photosensitizer [Ru(bpy)3 ](2+) and the oxidant persulfate, visible-light-driven water oxidation with turnover numbers of approximately 1150 and turnover frequencies of about 1.75 s(-1) is observed. Electrochemical, mass-spectrometric, and spectroscopic studies provide insight into the cluster stability and reactivity. This compound could serve as a model for the molecular structure and reactivity of the OEC and for heterogeneous metal oxide water-oxidation catalysts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. ADVANCED OXIDATION TECHNOLOGIES FOR THE TREATMENT OF CONTAMINATED GROUNDWATER

    EPA Science Inventory

    This paper presents information on two pilot-field appliations of advanced oxidation technologies for contaminated groundwater with organis. The two UV/oxidation technologies were developed by Ultrox International of Santa Ana, California and Peroxidatrion Systems, Inc. of Tucso...

  1. ADVANCED OXIDATION TECHNOLOGIES FOR THE TREATMENT OF CONTAMINATED GROUNDWATER

    EPA Science Inventory

    This paper presents information on two pilot-field appliations of advanced oxidation technologies for contaminated groundwater with organis. The two UV/oxidation technologies were developed by Ultrox International of Santa Ana, California and Peroxidatrion Systems, Inc. of Tucso...

  2. Commercial applications of electron beam advanced oxidation technology

    NASA Astrophysics Data System (ADS)

    Curry, Randy D.; Bosma, John T.

    1995-03-01

    Emerging commercial applications of electron-beam advanced oxidation technology offer a significant advancement in the treatment of waste steams. Both electron beam and X-ray (Brehmsstrahlung) advanced oxidation processes have been shown to be effective in the destruction of volatile and semivolatile organic compounds. Emerging commercial applications, however, far exceed in scope current applications of oxidation technologies for the destruction of simple semivolatile and volatile organic compounds in water. Emerging applications include direct treatment of contaminated soil, removal of metal ions from water and sterilization of water, sludges, and food. Application of electron beam advanced oxidation technologies are reviewed, along with electron- beam-generated X-ray (Brehmsstrahlung) advanced oxidation processes. Advantages of each technology are discussed along with advanced accelerator technologies which are applicable for commercial processing of waste streams. An overview of the U.S. companies and laboratories participating in this research area are included in this discussion.

  3. Iron oxides stimulate sulfate-driven anaerobic methane oxidation in seeps.

    PubMed

    Sivan, Orit; Antler, Gilad; Turchyn, Alexandra V; Marlow, Jeffrey J; Orphan, Victoria J

    2014-10-07

    Seep sediments are dominated by intensive microbial sulfate reduction coupled to the anaerobic oxidation of methane (AOM). Through geochemical measurements of incubation experiments with methane seep sediments collected from Hydrate Ridge, we provide insight into the role of iron oxides in sulfate-driven AOM. Seep sediments incubated with (13)C-labeled methane showed co-occurring sulfate reduction, AOM, and methanogenesis. The isotope fractionation factors for sulfur and oxygen isotopes in sulfate were about 40‰ and 22‰, respectively, reinforcing the difference between microbial sulfate reduction in methane seeps versus other sedimentary environments (for example, sulfur isotope fractionation above 60‰ in sulfate reduction coupled to organic carbon oxidation or in diffusive sedimentary sulfate-methane transition zone). The addition of hematite to these microcosm experiments resulted in significant microbial iron reduction as well as enhancing sulfate-driven AOM. The magnitude of the isotope fractionation of sulfur and oxygen isotopes in sulfate from these incubations was lowered by about 50%, indicating the involvement of iron oxides during sulfate reduction in methane seeps. The similar relative change between the oxygen versus sulfur isotopes of sulfate in all experiments (with and without hematite addition) suggests that oxidized forms of iron, naturally present in the sediment incubations, were involved in sulfate reduction, with hematite addition increasing the sulfate recycling or the activity of sulfur-cycling microorganisms by about 40%. These results highlight a role for natural iron oxides during bacterial sulfate reduction in methane seeps not only as nutrient but also as stimulator of sulfur recycling.

  4. Iron oxides stimulate sulfate-driven anaerobic methane oxidation in seeps

    PubMed Central

    Sivan, Orit; Antler, Gilad; Turchyn, Alexandra V.; Marlow, Jeffrey J.; Orphan, Victoria J.

    2014-01-01

    Seep sediments are dominated by intensive microbial sulfate reduction coupled to the anaerobic oxidation of methane (AOM). Through geochemical measurements of incubation experiments with methane seep sediments collected from Hydrate Ridge, we provide insight into the role of iron oxides in sulfate-driven AOM. Seep sediments incubated with 13C-labeled methane showed co-occurring sulfate reduction, AOM, and methanogenesis. The isotope fractionation factors for sulfur and oxygen isotopes in sulfate were about 40‰ and 22‰, respectively, reinforcing the difference between microbial sulfate reduction in methane seeps versus other sedimentary environments (for example, sulfur isotope fractionation above 60‰ in sulfate reduction coupled to organic carbon oxidation or in diffusive sedimentary sulfate–methane transition zone). The addition of hematite to these microcosm experiments resulted in significant microbial iron reduction as well as enhancing sulfate-driven AOM. The magnitude of the isotope fractionation of sulfur and oxygen isotopes in sulfate from these incubations was lowered by about 50%, indicating the involvement of iron oxides during sulfate reduction in methane seeps. The similar relative change between the oxygen versus sulfur isotopes of sulfate in all experiments (with and without hematite addition) suggests that oxidized forms of iron, naturally present in the sediment incubations, were involved in sulfate reduction, with hematite addition increasing the sulfate recycling or the activity of sulfur-cycling microorganisms by about 40%. These results highlight a role for natural iron oxides during bacterial sulfate reduction in methane seeps not only as nutrient but also as stimulator of sulfur recycling. PMID:25246590

  5. RF-driven advanced modes of ITER operation

    SciTech Connect

    Garcia, J.; Artaud, J. F.; Basiuk, V.; Decker, J.; Giruzzi, G.; Hawkes, N.; Imbeaux, F.; Litaudon, X.; Mailloux, J.; Peysson, Y.; Schneider, M.; Brix, M.

    2009-11-26

    The impact of the Radio Frequency heating and current drive systems on the ITER advanced scenarios is analyzed by means of the CRONOS suite of codes for integrated tokamak modelling. As a first step, the code is applied to analyze a high power advanced scenario discharge of JET in order to validate both the heating and current drive modules and the overall simulation procedure. Then, ITER advanced scenarios, based on Radio Frequency systems, are studied on the basis of previous results. These simulations show that both hybrid and steady-state scenarios could be possible within the ITER specifications, using RF heating and current drive only.

  6. RF-driven advanced modes of ITER operation

    NASA Astrophysics Data System (ADS)

    Garcia, J.; Artaud, J. F.; Basiuk, V.; Brix, M.; Decker, J.; Giruzzi, G.; Hawkes, N.; Imbeaux, F.; Litaudon, X.; Mailloux, J.; Peysson, Y.; Schneider, M.

    2009-11-01

    The impact of the Radio Frequency heating and current drive systems on the ITER advanced scenarios is analyzed by means of the CRONOS suite of codes for integrated tokamak modelling. As a first step, the code is applied to analyze a high power advanced scenario discharge of JET in order to validate both the heating and current drive modules and the overall simulation procedure. Then, ITER advanced scenarios, based on Radio Frequency systems, are studied on the basis of previous results. These simulations show that both hybrid and steady-state scenarios could be possible within the ITER specifications, using RF heating and current drive only.

  7. Advanced oxidation technologies for chemical demilitarization

    SciTech Connect

    Rosocha, L.A.; Korzekwa, R.A.; Monagle, M.; Coogan, J.J.; Tennant, R.A.; Brown, L.F.; Currier, R.P.

    1996-12-31

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory. The main project objective was to establish a technical basis for future program development in the area of chemical warfare agent destruction using a Los Alamos-developed advanced oxidation process: a two-stage device consisting of thermal packed-bed reactor (PBR) and a nonthermal plasma (NTP) reactor. Various compounds were evaluated as potential surrogates for chemical warfare (CW) agents. Representative effluent mass balances were projected for future comparisons with incinerators. The design and construction of lab-scale PBR/NTP reactors (consisting of a liquid injection and metering system, electric furnace, condensers, chemical traps, plasma reactors, power supplies, and chemical diagnostics) has been completed. This equipment, the experience gained from chemical-processing experiments, process modeling, and an initial demonstration of the feasibility of closed-loop operation, have provided a technical basis for further demonstrations and program development efforts.

  8. Advances in Optimizing Weather Driven Electric Power Systems.

    NASA Astrophysics Data System (ADS)

    Clack, C.; MacDonald, A. E.; Alexander, A.; Dunbar, A. D.; Xie, Y.; Wilczak, J. M.

    2014-12-01

    The importance of weather-driven renewable energies for the United States (and global) energy portfolio is growing. The main perceived problems with weather-driven renewable energies are their intermittent nature, low power density, and high costs. The National Energy with Weather System Simulator (NEWS) is a mathematical optimization tool that allows the construction of weather-driven energy sources that will work in harmony with the needs of the system. For example, it will match the electric load, reduce variability, decrease costs, and abate carbon emissions. One important test run included existing US carbon-free power sources, natural gas power when needed, and a High Voltage Direct Current power transmission network. This study shows that the costs and carbon emissions from an optimally designed national system decrease with geographic size. It shows that with achievable estimates of wind and solar generation costs, that the US could decrease its carbon emissions by up to 80% by the early 2030s, without an increase in electric costs. The key requirement would be a 48 state network of HVDC transmission, creating a national market for electricity not possible in the current AC grid. These results were found without the need for storage. Further, we tested the effect of changing natural gas fuel prices on the optimal configuration of the national electric power system. Another test that was carried out was an extension to global regions. The extension study shows that the same properties found in the US study extend to the most populous regions of the planet. The extra test is a simplified version of the US study, and is where much more research can be carried out. We compare our results to other model results.

  9. SULFATE RADICAL-BASED ADVANCED OXIDATION PROCESSES- ACS MEETING

    EPA Science Inventory

    This paper will present an overview of sulfate radical-based advanced oxidation technologies for the destruction of environmentally toxic chemicals in wastewater, industrial water, groundwater and sources of water supply. The paper will include fundamental aspects of the generati...

  10. SULFATE RADICAL-BASED ADVANCED OXIDATION PROCESSES- ACS MEETING

    EPA Science Inventory

    This paper will present an overview of sulfate radical-based advanced oxidation technologies for the destruction of environmentally toxic chemicals in wastewater, industrial water, groundwater and sources of water supply. The paper will include fundamental aspects of the generati...

  11. Oxidation-Reduction Resistance of Advanced Copper Alloys

    NASA Technical Reports Server (NTRS)

    Greenbauer-Seng, L. (Technical Monitor); Thomas-Ogbuji, L.; Humphrey, D. L.; Setlock, J. A.

    2003-01-01

    Resistance to oxidation and blanching is a key issue for advanced copper alloys under development for NASA's next generation of reusable launch vehicles. Candidate alloys, including dispersion-strengthened Cu-Cr-Nb, solution-strengthened Cu-Ag-Zr, and ODS Cu-Al2O3, are being evaluated for oxidation resistance by static TGA exposures in low-p(O2) and cyclic oxidation in air, and by cyclic oxidation-reduction exposures (using air for oxidation and CO/CO2 or H2/Ar for reduction) to simulate expected service environments. The test protocol and results are presented.

  12. Advanced scheme for high-yield laser driven nuclear reactions

    NASA Astrophysics Data System (ADS)

    Margarone, D.; Picciotto, A.; Velyhan, A.; Krasa, J.; Kucharik, M.; Mangione, A.; Szydlowsky, A.; Malinowska, A.; Bertuccio, G.; Shi, Y.; Crivellari, M.; Ullschmied, J.; Bellutti, P.; Korn, G.

    2015-01-01

    The use of a low contrast nanosecond laser pulse with a relatively low intensity (3  ×  1016 W cm-2) allowed the enhancing of the yield of induced nuclear reactions in advanced solid targets. In particular the ‘ultraclean’ proton-boron fusion reaction, producing energetic alpha particles without neutron generation, was chosen. A spatially well-defined layer of boron dopants in a hydrogen-enriched silicon substrate was used as a target. A combination of the specific target composition and the laser pulse temporal shape allowed the enhancing of the yield of alpha particles up to 109 per steradian. This result can be ascribed to the interaction of the long-laser pre-pulse with the target and to the optimal target geometry and composition.

  13. Magnetically-Driven Isentropic Compression Status and Future Advances

    NASA Astrophysics Data System (ADS)

    Deeney, Christopher

    2005-07-01

    Since the development of magnetically driven isentropic compression experiments (ICE) on the Z accelerator by Asay et al, this technique has continued to grow in maturity. At lower pressures, isentropic compression has been employed to identify and then study phase transitions and their kinetics. In addition, experiments have used the same techniques to study re-solidification, the response of explosives, and the crush up of porous materials. Most of these experiments rely on the ability of ICE to generate very smooth ramps that can be applied to multiple samples for relative experiments. For equation of state studies, the intrinsic accuracy and peak pressures continue to demand improvement in understanding, analysis techniques and diagnostics. We have spent significant effort in these areas over the last few years because we believe that we must demonstrate a well characterized and understood method to obtain accurate EOS data with well-behaved materials to give confidence in future comparisons between ICE data and calculations of material properties. In our presentation, we will discuss the status of Z experiments, our recent data at multi-megabar pressures with aluminum and other materials, and the status of our analysis abilities. We will also discuss the need for future improvements in diagnostics plus the anticipated capabilities of the ZR facility and the small pulser. This work was supported by the United States Department of Energy's National Nuclear Security Administration under contract No. DE-AC04-94AL85000. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company..

  14. New developments advance forced-oxidation FGD

    SciTech Connect

    Ellison, W.; Kutemeyer, P.M.

    1983-02-01

    In the US, many utility companies are specifying forced oxidation to help to stabilize the sludge from wet-limestone scrubbers. This technique is already used in Japan and West Germany. The oxidized sludge can be more easily dewatered and thus requires considerably less disposal area than is needed for ponding the FGD sludge. The solids can also be upgraded to a commercial-grade gypsum. The processes required and the systems currently in use in Japan and West Germany are described.

  15. ADVANCED OXIDATION: OXALATE DECOMPOSITION TESTING WITH OZONE

    SciTech Connect

    Ketusky, E.; Subramanian, K.

    2012-02-29

    At the Savannah River Site (SRS), oxalic acid is currently considered the preferred agent for chemically cleaning the large underground Liquid Radioactive Waste Tanks. It is applied only in the final stages of emptying a tank when generally less than 5,000 kg of waste solids remain, and slurrying based removal methods are no-longer effective. The use of oxalic acid is preferred because of its combined dissolution and chelating properties, as well as the fact that corrosion to the carbon steel tank walls can be controlled. Although oxalic acid is the preferred agent, there are significant potential downstream impacts. Impacts include: (1) Degraded evaporator operation; (2) Resultant oxalate precipitates taking away critically needed operating volume; and (3) Eventual creation of significant volumes of additional feed to salt processing. As an alternative to dealing with the downstream impacts, oxalate decomposition using variations of ozone based Advanced Oxidation Process (AOP) were investigated. In general AOPs use ozone or peroxide and a catalyst to create hydroxyl radicals. Hydroxyl radicals have among the highest oxidation potentials, and are commonly used to decompose organics. Although oxalate is considered among the most difficult organic to decompose, the ability of hydroxyl radicals to decompose oxalate is considered to be well demonstrated. In addition, as AOPs are considered to be 'green' their use enables any net chemical additions to the waste to be minimized. In order to test the ability to decompose the oxalate and determine the decomposition rates, a test rig was designed, where 10 vol% ozone would be educted into a spent oxalic acid decomposition loop, with the loop maintained at 70 C and recirculated at 40L/min. Each of the spent oxalic acid streams would be created from three oxalic acid strikes of an F-area simulant (i.e., Purex = high Fe/Al concentration) and H-area simulant (i.e., H area modified Purex = high Al/Fe concentration) after nearing

  16. Steam Oxidation of Advanced Steam Turbine Alloys

    SciTech Connect

    Holcomb, Gordon R.

    2008-01-01

    Power generation from coal using ultra supercritical steam results in improved fuel efficiency and decreased greenhouse gas emissions. Results of ongoing research into the oxidation of candidate nickel-base alloys for ultra supercritical steam turbines are presented. Exposure conditions range from moist air at atmospheric pressure (650°C to 800°C) to steam at 34.5 MPa (650°C to 760°C). Parabolic scale growth coupled with internal oxidation and reactive evaporation of chromia are the primary corrosion mechanisms.

  17. Efficient chemical and visible-light-driven water oxidation using nickel complexes and salts as precatalysts.

    PubMed

    Chen, Gui; Chen, Lingjing; Ng, Siu-Mui; Lau, Tai-Chu

    2014-01-01

    Chemical and visible-light-driven water oxidation catalyzed by a number of Ni complexes and salts have been investigated at pH 7-9 in borate buffer. For chemical oxidation, [Ru(bpy)3](3+) (bpy = 2,2'-bipyridine) was used as the oxidant, with turnover numbers (TONs) >65 and a maximum turnover frequency (TOFmax) >0.9 s(-1). Notably, simple Ni salts such as Ni(NO3 )2 are more active than Ni complexes that bear multidentate N-donor ligands. The Ni complexes and salts are also active catalysts for visible-light-driven water oxidation that uses [Ru(bpy)3](2+) as the photosensitizer and S2 O8 (2-) as the sacrificial oxidant; a TON>1200 was obtained at pH 8.5 by using Ni(NO3)2 as the catalyst. Dynamic light scattering measurements revealed the formation of nanoparticles in chemical and visible-light-driven water oxidation by the Ni catalysts. These nanoparticles aggregated during water oxidation to form submicron particles that were isolated and shown to be partially reduced β-NiOOH by various techniques, which include SEM, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, XRD, and IR spectroscopy. These results suggest that the Ni complexes and salts act as precatalysts that decompose under oxidative conditions to form an active nickel oxide catalyst. The nature of this active oxide catalyst is discussed.

  18. Advanced launch system. Advanced development oxidizer turbopump program

    NASA Technical Reports Server (NTRS)

    1993-01-01

    On May 19, 1989, Pratt & Whitney was awarded contract NAS8-37595 by the National Aeronautics and Space Administration, Marshall Space Flight Center, Huntsville Alabama for an Advanced Development Program (ADP) to design, develop and demonstrate a highly reliable low cost, liquid oxygen turbopump for the Advanced Launch System (ALS). The ALS had an overall goal of reducing the cost of placing payloads in orbit by an order of magnitude. This goal would require a substantial reduction in life cycle costs, with emphasis on recurring costs, compared to current launch vehicles. Engine studies supporting these efforts were made for the Space Transportation Main Engine (STME). The emphasis on low cost required design simplification of components and subsystems such that the ground maintenance and test operations was minimized. The results of the Oxygen Turbopump ADP technology effort would provide data to be used in the STME. Initially the STME baseline was a gas generator cycle engine with a vacuum thrust level of 580,000 lbf. This was later increased to 650,000 lbf and the oxygen turbopump design approach was changed to reflect the new thrust level. It was intended that this ADP program be conducted in two phases. Phase 1, a basic phase, would encompass the preliminary design effort, and Phase II, an optional contract phase to cover design, fabrication and test evaluation of an oxygen turbopump at a component test facility at the NASA John C. Stennis Space Center in Mississippi. The basic phase included preliminary design and analysis, evaluation of low cost concepts, and evaluation of fabrication techniques. The option phase included design of the pump and support hardware, analysis of the final configuration to ensure design integrity, fabrication of hardware to demonstrate low cost, DVS Testing of hardware to verify the design, assembly of the turbopump and full scale turbopump testing. In December 1990, the intent of this ADP to support the design and development was

  19. Charge transport-driven selective oxidation of graphene.

    PubMed

    Lee, Young Keun; Choi, Hongkyw; Lee, Changhwan; Lee, Hyunsoo; Goddeti, Kalyan C; Moon, Song Yi; Doh, Won Hui; Baik, Jaeyoon; Kim, Jin-Soo; Choi, Jin Sik; Choi, Choon-Gi; Park, Jeong Young

    2016-06-02

    Due to the tunability of the physical, electrical, and optical characteristics of graphene, precisely controlling graphene oxidation is of great importance for potential applications of graphene-based electronics. Here, we demonstrate a facile and precise way for graphene oxidation controlled by photoexcited charge transfer depending on the substrate and bias voltage. It is observed that graphene on TiO2 is easily oxidized under UV-ozone treatment, while graphene on SiO2 remains unchanged. The mechanism for the selective oxidation of graphene on TiO2 is associated with charge transfer from the TiO2 to the graphene. Raman spectra were used to investigate the graphene following applied bias voltages on the graphene/TiO2 diode under UV-ozone exposure. We found that under a reverse bias of 0.6 V on the graphene/TiO2 diode, graphene oxidation was accelerated under UV-ozone exposure, thus confirming the role of charge transfer between the graphene and the TiO2 that results in the selective oxidation of the graphene. The selective oxidation of graphene can be utilized for the precise, nanoscale patterning of the graphene oxide and locally patterned chemical doping, finally leading to the feasibility and expansion of a variety of graphene-based applications.

  20. Air-Driven Potassium Iodide-Mediated Oxidative Photocyclization of Stilbene Derivatives.

    PubMed

    Matsushima, Tomoya; Kobayashi, Sayaka; Watanabe, Soichiro

    2016-09-02

    A new method has been developed for the potassium iodide-mediated oxidative photocyclization of stilbene derivatives. Compared with conventional iodine-mediated oxidative photocyclization reactions, this new method requires shorter reaction times and affords cyclized products in yields of 45-97%. This reaction proceeds with a catalytic amount of potassium iodide and works in an air-driven manner without the addition of an external scavenger. The radical-mediated oxidative photocyclization of stilbene derivatives using TEMPO was also investigated.

  1. Supported versus colloidal zinc oxide for advanced oxidation processes

    NASA Astrophysics Data System (ADS)

    Laxman, Karthik; Al Rashdi, Manal; Al Sabahi, Jamal; Al Abri, Mohammed; Dutta, Joydeep

    2017-07-01

    Photocatalysis is a green technology which typically utilizes either supported or colloidal catalysts for the mineralization of aqueous organic contaminants. Catalyst surface area and surface energy are the primary factors determining its efficiency, but correlation between the two is still unclear. This work explores their relation and hierarchy in a photocatalytic process involving both supported and colloidal catalysts. In order to do this the active surface areas of supported zinc oxide nanorods (ZnO NR's) and colloidal zinc oxide nanoparticles (having different surface energies) were equalized and their phenol oxidation mechanism and capacity was analyzed. It was observed that while surface energy had subtle effects on the oxidation rate of the catalysts, the degradation efficiency was primarily a function of the surface area; which makes it a better parameter for comparison when studying different catalyst forms of the same material. Thus we build a case for the use of supported catalysts, wherein their catalytic efficiency was tested to be unaltered over several days under both natural and artificial light, suggesting their viability for practical applications.

  2. Oxidation of artificial sweetener sucralose by advanced oxidation processes: a review.

    PubMed

    Sharma, Virender K; Oturan, Mehmet; Kim, Hyunook

    2014-01-01

    Sucralose, a chlorinated carbohydrate, has shown its increased use as an artificial sweetener and persistently exists in wastewater treatment plant effluents and aquatic environment. This paper aims to review possible degradation of sucralose and related carbohydrates by biological, electrochemical, chemical, and advanced oxidation processes. Biodegradation of sucralose in waterworks did not occur significantly. Electrochemical oxidation of carbohydrates may be applied to seek degradation of sucralose. The kinetics of the oxidation of sucralose and the related carbohydrates by different oxidative species is compared. Free chlorine, ozone, and ferrate did not show any potential to degrade sucralose in water. Advanced oxidation processes, generating highly strong oxidizing agent hydroxyl radicals ((•)OH), have demonstrated effectiveness in transforming sucralose in water. The mechanism of oxidation of sucralose by (•)OH is briefly discussed.

  3. Process for light-driven hydrocarbon oxidation at ambient temperatures

    DOEpatents

    Shelnutt, John A.

    1990-01-01

    A photochemical reaction for the oxidation of hydrocarbons uses molecular oxygen as the oxidant. A reductive photoredox cycle that uses a tin(IV)- or antimony(V)-porphyrin photosensitizer generates the reducing equivalents required to activate oxygen. This artificial photosynthesis system drives a catalytic cycle, which mimics the cytochrome P.sub.450 reaction, to oxidize hydrocarbons. An iron(III)- or manganese(III)-porphyrin is used as the hydrocarbon-oxidation catalyst. Methylviologen can be used as a redox relay molecule to provide for electron-transfer from the reduced photosensitizer to the Fe or Mn porphyrin. The system is long-lived and may be used in photo-initiated spectroscopic studies of the reaction to determine reaction rates and intermediates.

  4. Charge transport-driven selective oxidation of graphene

    NASA Astrophysics Data System (ADS)

    Lee, Young Keun; Choi, Hongkyw; Lee, Changhwan; Lee, Hyunsoo; Goddeti, Kalyan C.; Moon, Song Yi; Doh, Won Hui; Baik, Jaeyoon; Kim, Jin-Soo; Choi, Jin Sik; Choi, Choon-Gi; Park, Jeong Young

    2016-06-01

    Due to the tunability of the physical, electrical, and optical characteristics of graphene, precisely controlling graphene oxidation is of great importance for potential applications of graphene-based electronics. Here, we demonstrate a facile and precise way for graphene oxidation controlled by photoexcited charge transfer depending on the substrate and bias voltage. It is observed that graphene on TiO2 is easily oxidized under UV-ozone treatment, while graphene on SiO2 remains unchanged. The mechanism for the selective oxidation of graphene on TiO2 is associated with charge transfer from the TiO2 to the graphene. Raman spectra were used to investigate the graphene following applied bias voltages on the graphene/TiO2 diode under UV-ozone exposure. We found that under a reverse bias of 0.6 V on the graphene/TiO2 diode, graphene oxidation was accelerated under UV-ozone exposure, thus confirming the role of charge transfer between the graphene and the TiO2 that results in the selective oxidation of the graphene. The selective oxidation of graphene can be utilized for the precise, nanoscale patterning of the graphene oxide and locally patterned chemical doping, finally leading to the feasibility and expansion of a variety of graphene-based applications.Due to the tunability of the physical, electrical, and optical characteristics of graphene, precisely controlling graphene oxidation is of great importance for potential applications of graphene-based electronics. Here, we demonstrate a facile and precise way for graphene oxidation controlled by photoexcited charge transfer depending on the substrate and bias voltage. It is observed that graphene on TiO2 is easily oxidized under UV-ozone treatment, while graphene on SiO2 remains unchanged. The mechanism for the selective oxidation of graphene on TiO2 is associated with charge transfer from the TiO2 to the graphene. Raman spectra were used to investigate the graphene following applied bias voltages on the graphene/TiO2

  5. Advanced metal oxide varistor concepts. Final report

    SciTech Connect

    Philipp, H.R.; Mahan, G.D.; Levinson, L.M.

    1984-07-01

    Zinc oxide varistors are ZnO-based ceramic semiconductor devices with highly nonlinear current-voltage characteristics similar to back-to-back Zener diodes but with much greater current, voltage, and energy-handling capabilities. Zinc oxide varistors have proven useful in a variety of applications, particularly as high-quality voltage suppression devices for the protection of ac and dc electric power transmission systems against the effects of transient overvoltages due to switching surges and lightning strikes. In the work described in this report, we have chosen to study simple varistor systems that use Bi or Pr as the varistor-forming additive and Co or Mn as the varistor-performance ingredient. Commercial varistor materials generally use Bi as the varistor-forming ingredient, and the sintering process in such material probably proceeds in the liquid phase. Varistor materials that use Pr as the varistor-forming ingredient are also produced commercially. However, owing to the high melting point of Pr/sub 2/O/sub 3/ compared to Bi/sub 2/O/sub 3/, sintering in these materials probably takes place in the solid state. The performance ingredients Co and Mn are present in almost all commercial mixes. Co is an interesting choice because it is known to introduce a deep level into ZnO, giving such varistors a green color.

  6. Recent advances in heterogeneous selective oxidation catalysis for sustainable chemistry.

    PubMed

    Guo, Zhen; Liu, Bin; Zhang, Qinghong; Deng, Weiping; Wang, Ye; Yang, Yanhui

    2014-05-21

    Oxidation catalysis not only plays a crucial role in the current chemical industry for the production of key intermediates such as alcohols, epoxides, aldehydes, ketones and organic acids, but also will contribute to the establishment of novel green and sustainable chemical processes. This review is devoted to dealing with selective oxidation reactions, which are important from the viewpoint of green and sustainable chemistry and still remain challenging. Actually, some well-known highly challenging chemical reactions involve selective oxidation reactions, such as the selective oxidation of methane by oxygen. On the other hand some important oxidation reactions, such as the aerobic oxidation of alcohols in the liquid phase and the preferential oxidation of carbon monoxide in hydrogen, have attracted much attention in recent years because of their high significance in green or energy chemistry. This article summarizes recent advances in the development of new catalytic materials or novel catalytic systems for these challenging oxidation reactions. A deep scientific understanding of the mechanisms, active species and active structures for these systems are also discussed. Furthermore, connections among these distinct catalytic oxidation systems are highlighted, to gain insight for the breakthrough in rational design of efficient catalytic systems for challenging oxidation reactions.

  7. AWAKE, The Advanced Proton Driven Plasma Wakefield Acceleration Experiment at CERN

    NASA Astrophysics Data System (ADS)

    Gschwendtner, E.; Adli, E.; Amorim, L.; Apsimon, R.; Assmann, R.; Bachmann, A.-M.; Batsch, F.; Bauche, J.; Berglyd Olsen, V. K.; Bernardini, M.; Bingham, R.; Biskup, B.; Bohl, T.; Bracco, C.; Burrows, P. N.; Burt, G.; Buttenschön, B.; Butterworth, A.; Caldwell, A.; Cascella, M.; Chevallay, E.; Cipiccia, S.; Damerau, H.; Deacon, L.; Dirksen, P.; Doebert, S.; Dorda, U.; Farmer, J.; Fedosseev, V.; Feldbaumer, E.; Fiorito, R.; Fonseca, R.; Friebel, F.; Gorn, A. A.; Grulke, O.; Hansen, J.; Hessler, C.; Hofle, W.; Holloway, J.; Hüther, M.; Jaroszynski, D.; Jensen, L.; Jolly, S.; Joulaei, A.; Kasim, M.; Keeble, F.; Li, Y.; Liu, S.; Lopes, N.; Lotov, K. V.; Mandry, S.; Martorelli, R.; Martyanov, M.; Mazzoni, S.; Mete, O.; Minakov, V. A.; Mitchell, J.; Moody, J.; Muggli, P.; Najmudin, Z.; Norreys, P.; Öz, E.; Pardons, A.; Pepitone, K.; Petrenko, A.; Plyushchev, G.; Pukhov, A.; Rieger, K.; Ruhl, H.; Salveter, F.; Savard, N.; Schmidt, J.; Seryi, A.; Shaposhnikova, E.; Sheng, Z. M.; Sherwood, P.; Silva, L.; Soby, L.; Sosedkin, A. P.; Spitsyn, R. I.; Trines, R.; Tuev, P. V.; Turner, M.; Verzilov, V.; Vieira, J.; Vincke, H.; Wei, Y.; Welsch, C. P.; Wing, M.; Xia, G.; Zhang, H.

    2016-09-01

    The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment at CERN and the world's first proton driven plasma wakefield acceleration experiment. The AWAKE experiment will be installed in the former CNGS facility and uses the 400 GeV/c proton beam bunches from the SPS. The first experiments will focus on the self-modulation instability of the long (rms 12 cm) proton bunch in the plasma. These experiments are planned for the end of 2016. Later, in 2017/2018, low energy ( 15 MeV) electrons will be externally injected into the sample wakefields and be accelerated beyond 1 GeV. The main goals of the experiment will be summarized. A summary of the AWAKE design and construction status will be presented.

  8. Hidden Interface Driven Exchange Coupling in Oxide Heterostructures

    DOE PAGES

    Chen, Aiping; Wang, Qiang; Fitzsimmons, Michael R.; ...

    2017-05-02

    In a variety of emergent phenomena have been enabled by interface engineering in complex oxides. The existence of an intrinsic interfacial layer has often been found at oxide heterointerfaces. But, the role of such an interlayerin controlling functionalities is not fully explored. Here, we report the control of the exchange bias (EB) in single-phase manganite thin films with nominallyuniform chemical composition across the interfaces. The sign of EB depends on the magnitude of the cooling field. A pinned layer, confirmed by polarized neutron reflectometry, provides the source of unidirectional anisotropy. The origin of the exchange bias coupling is discussed inmore » terms of magnetic interactions between the interfacial ferromagnetically reduced layer and the bulk ferromagnetic region. The sign of EB is related to the frustration of antiferromagnetic coupling between the ferromagnetic region and the pinned layer. These results shed new light on using oxide interfaces to design functional spintronic devices.« less

  9. Advanced oxidation of acridine orange by aqueous alkaline iodine.

    PubMed

    Azmat, Rafia; Qamar, Noshab; Naz, Raheela; Khursheed, Anum

    2016-11-01

    The advanced oxidation process is certainly used for the dye waste water treatment. In this continuation a new advanced oxidation via aqueous alkaline iodine was developed for the oxidation of acridine orange (AO) {3, 6 -bis (dimethylamino) acridine zinc chloride double salt}. Oxidation Kinetics of AO by alkaline solution of iodine was investigated spectrophotometrically at λmax 491 nm. The reaction was monitored at various operational parameters like several concentrations of dye and iodine, pH, salt electrolyte and temperature. The initial steps of oxidation kinetics followed fractional order reaction with respect to the dye while depend upon the incremental amount of iodine to certain extent whereas maximum oxidation of AO was achieved at high pH. Decline in the reaction rate in the presence of salt electrolyte suggested the presence of oppositely charged species in the rate determining step. Kinetic data revealed that the de-colorization mechanism involves triodate (I3(-)) species, instead of hypoidate (OI(-)) and hypiodous acid (HOI), in alkaline medium during the photo-excitation of hydrolyzed AO. Alleviated concentration of alkali result in decreasing of rate of reaction, clearly indicate that the iodine species are active oxidizing species instead of OH radical. Activation parameters at elevated temperatures were determined which revealed that highly solvated state of dye complex existed into solution. Reaction mixture was subjected to UV/Visible and GC mass spectrum analysis that proves the secondary consecutive reaction was operative in rate determining step and finally dye complex end into smaller fragments.

  10. Two-dimensional oxides: multifunctional materials for advanced technologies.

    PubMed

    Pacchioni, Gianfranco

    2012-08-13

    The last decade has seen spectacular progress in the design, preparation, and characterization down to the atomic scale of oxide ultrathin films of few nanometers thickness grown on a different material. This has paved the way towards several sophisticated applications in advanced technologies. By playing around with the low-dimensionality of the oxide layer, which sometimes leads to truly two-dimensional systems, one can exploit new properties and functionalities that are not present in the corresponding bulk materials or thick films. In this review we provide some clues about the most recent advances in the design of these systems based on modern electronic structure theory and on their preparation and characterization with specifically developed growth techniques and analytical methods. We show how two-dimensional oxides can be used in mature technologies by providing added value to existing materials, or in new technologies based on completely new paradigms. The fields in which two-dimensional oxides are used are classified based on the properties that are exploited, chemical or physical. With respect to chemical properties we discuss use of oxide ultrathin films in catalysis, solid oxide fuel cells, gas sensors, corrosion protection, and biocompatible materials; regarding the physical properties we discuss metal-oxide field effect transistors and memristors, spintronic devices, ferroelectrics and thermoelectrics, and solar energy materials.

  11. Recent advances of lanthanum-based perovskite oxides for catalysis

    DOE PAGES

    Zhu, Huiyuan; Zhang, Pengfei; Dai, Sheng

    2015-09-21

    There is a need to reduce the use of noble metal elements especially in the field of catalysis, where noble metals are ubiquitously applied. To this end, perovskite oxides, an important class of mixed oxide, have been attracting increasing attention for decades as potential replacements. Benefiting from the extraordinary tunability of their compositions and structures, perovskite oxides can be rationally tailored and equipped with targeted physical and chemical properties e.g. redox behavior, oxygen mobility, and ion conductivity for enhanced catalysis. Recently, the development of highly efficient perovskite oxide catalysts has been extensively studied. This review article summarizes the recent developmentmore » of lanthanum-based perovskite oxides as advanced catalysts for both energy conversion applications and traditional heterogeneous reactions.« less

  12. Recent advances of lanthanum-based perovskite oxides for catalysis

    SciTech Connect

    Zhu, Huiyuan; Zhang, Pengfei; Dai, Sheng

    2015-09-21

    There is a need to reduce the use of noble metal elements especially in the field of catalysis, where noble metals are ubiquitously applied. To this end, perovskite oxides, an important class of mixed oxide, have been attracting increasing attention for decades as potential replacements. Benefiting from the extraordinary tunability of their compositions and structures, perovskite oxides can be rationally tailored and equipped with targeted physical and chemical properties e.g. redox behavior, oxygen mobility, and ion conductivity for enhanced catalysis. Recently, the development of highly efficient perovskite oxide catalysts has been extensively studied. This review article summarizes the recent development of lanthanum-based perovskite oxides as advanced catalysts for both energy conversion applications and traditional heterogeneous reactions.

  13. Polarization-driven catalysis via ferroelectric oxide surfaces.

    PubMed

    Kakekhani, Arvin; Ismail-Beigi, Sohrab

    2016-07-20

    The surface chemistry and physics of oxide ferroelectric surfaces with a fixed polarization state have been studied experimentally for some time. Here, we discuss the possibility of using these materials in a different mode, namely under cyclically changing polarization conditions achievable via periodic perturbations by external fields (e.g., temperature, strain or electric field). We use Density Functional Theory (DFT) and electronic structure analysis to understand the polarization-dependent surface physics and chemistry of ferroelectric oxide PbTiO3 as an example of this class of materials. This knowledge is then applied to design catalytic cycles for industrially important reactions including NOx direct decomposition and SO2 oxidation into SO3. The possibility of catalyzing direct partial oxidation of methane to methanol is also investigated. More generally, we discuss how using ferroelectrics under cyclically changing polarization conditions can help overcome some of the fundamental challenges facing the catalysis community such as the limitations imposed by the Sabatier principle and scaling relations.

  14. Advanced oxidation processes with coke plant wastewater treatment.

    PubMed

    Krzywicka, A; Kwarciak-Kozłowska, A

    2014-01-01

    The aim of this study was to determine the most efficient method of coke wastewater treatment. This research examined two processes - advanced oxidation with Fenton and photo-Fenton reaction. It was observed that the use of ultraviolet radiation with Fenton process had a better result in removal of impurities.

  15. Advanced materials for solid oxide fuel cells

    SciTech Connect

    Armstrong, T.R.; Stevenson, J.

    1995-08-01

    The purpose of this research is to improve the properties of the current state-of-the-art materials used for solid oxide fuel cells (SOFCs). The objectives are to: (1) develop materials based on modifications of the state-of-the-art materials; (2) minimize or eliminate stability problems in the cathode, anode, and interconnect; (3) Electrochemically evaluate (in reproducible and controlled laboratory tests) the current state-of-the-art air electrode materials and cathode/electrolyte interfacial properties; (4) Develop accelerated electrochemical test methods to evaluate the performance of SOFCs under controlled and reproducible conditions; and (5) Develop and test materials for use in low-temperature SOFCs. The goal is to modify and improve the current state-of-the-art materials and minimize the total number of cations in each material to avoid negative effects on the materials properties. Materials to reduce potential deleterious interactions, (3) improve thermal, electrical, and electrochemical properties, (4) develop methods to synthesize both state-of-the-art and alternative materials for the simultaneous fabricatoin and consolidation in air of the interconnections and electrodes with the solid electrolyte, and (5) understand electrochemical reactions at materials interfaces and the effects of component composition and processing on those reactions.

  16. Defect driven tailoring of colossal dielectricity of Reduced Graphene Oxide

    SciTech Connect

    Sarkar, S.; Mondal, A.; Dey, K.; Ray, R.

    2016-02-15

    Highlights: • Reduced graphene oxides (RGO) are prepared by two chemical routes. • Defects in RGO are characterized by Raman, FTIR and XPS studies. • Defects tailor colossal dielectricity in RGO. - Abstract: Reduced graphene oxide (RGO) is prepared in two different chemical routes where reduction of graphene oxide is performed by hydrazine hydrate and through high pressure in hydrothermal reactor. Samples are characterized by X-ray powdered diffraction (XRD), thermo gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM) and tunneling electron microscopy (TEM). Types of defects are probed by Raman, FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS). UV–vis absorption reveals different optical band gaps of the two RGOs. Conductivity mechanism is studied through I–V measurements displaying different characteristic features which are addressed due to the presence of defects appeared in different synthesis. Significantly high value (∼10{sup 4}) of dielectric permittivity at 10 MHz is attractive for technological application which could be tuned by the defects present in RGO.

  17. Advanced Launch System advanced development oxidizer turbopump program: Technical implementation plan

    NASA Technical Reports Server (NTRS)

    Ferlita, F.

    1989-01-01

    The Advanced Launch Systems (ALS) Advanced Development Oxidizer Turbopump Program has designed, fabricated and demonstrated a low cost, highly reliable oxidizer turbopump for the Space Transportation Engine that minimizes the recurring cost for the ALS engines. Pratt and Whitney's (P and W's) plan for integrating the analyses, testing, fabrication, and other program efforts is addressed. This plan offers a comprehensive description of the total effort required to design, fabricate, and test the ALS oxidizer turbopump. The proposed ALS oxidizer turbopump reduces turbopump costs over current designs by taking advantage of design simplicity and state-of-the-art materials and producibility features without compromising system reliability. This is accomplished by selecting turbopump operating conditions that are within known successful operating regions and by using proven manufacturing techniques.

  18. Oxidative Lipidomics Coming of Age: Advances in Analysis of Oxidized Phospholipids in Physiology and Pathology

    PubMed Central

    Pitt, Andrew R.

    2015-01-01

    Abstract Significance: Oxidized phospholipids are now well recognized as markers of biological oxidative stress and bioactive molecules with both pro-inflammatory and anti-inflammatory effects. While analytical methods continue to be developed for studies of generic lipid oxidation, mass spectrometry (MS) has underpinned the advances in knowledge of specific oxidized phospholipids by allowing their identification and characterization, and it is responsible for the expansion of oxidative lipidomics. Recent Advances: Studies of oxidized phospholipids in biological samples, from both animal models and clinical samples, have been facilitated by the recent improvements in MS, especially targeted routines that depend on the fragmentation pattern of the parent molecular ion and improved resolution and mass accuracy. MS can be used to identify selectively individual compounds or groups of compounds with common features, which greatly improves the sensitivity and specificity of detection. Application of these methods has enabled important advances in understanding the mechanisms of inflammatory diseases such as atherosclerosis, steatohepatitis, leprosy, and cystic fibrosis, and it offers potential for developing biomarkers of molecular aspects of the diseases. Critical Issues and Future Directions: The future in this field will depend on development of improved MS technologies, such as ion mobility, novel enrichment methods and databases, and software for data analysis, owing to the very large amount of data generated in these experiments. Imaging of oxidized phospholipids in tissue MS is an additional exciting direction emerging that can be expected to advance understanding of physiology and disease. Antioxid. Redox Signal. 22, 1646–1666. PMID:25694038

  19. Mild Oxidation Promotes and Advanced Oxidation Impairs Remodeling of Human High-Density Lipoprotein in vitro

    PubMed Central

    Gao, Xuan; Jayaraman, Shobini; Gursky, Olga

    2008-01-01

    SUMMARY High-density lipoproteins (HDL) prevent atherosclerosis by removing cholesterol from macrophages and by exerting anti-oxidant and anti-inflammatory effects. Oxidation is thought to impair HDL functions, yet certain oxidative modifications may be advantageous; thus, mild oxidation reportedly enhances cell cholesterol uptake by HDL whereas extensive oxidation impairs it. To elucidate the underlying energetic and structural basis, we analyzed the effects of copper and hypochlorite (that preferentially oxidize lipids and proteins, respectively) on thermal stability of plasma spherical HDL. Circular dichroism, light scattering, calorimetry, gel electrophoresis and electron microscopy showed that mild oxidation destabilizes HDL and accelerates protein dissociation and lipoprotein fusion, while extensive oxidation inhibits these reactions; this inhibition correlates with massive protein cross-linking and lipolysis. We propose that mild oxidation lowers kinetic barriers for HDL remodeling due to diminished apolipoprotein affinity for lipids resulting from oxidation of methionine and aromatic residues in apolipoproteins A-I and A-II followed by protein cross-linking into dimers and/or trimers. In contrast, advanced oxidation inhibits protein dissociation and HDL fusion due to lipid re-distribution from core to surface upon lipolysis and to massive protein cross-linking. Our results help reconcile the apparent controversy in the studies of oxidized HDL and suggest that mild oxidation may benefit HDL functions. PMID:18190928

  20. Mild oxidation promotes and advanced oxidation impairs remodeling of human high-density lipoprotein in vitro.

    PubMed

    Gao, Xuan; Jayaraman, Shobini; Gursky, Olga

    2008-02-29

    High-density lipoproteins (HDLs) prevent atherosclerosis by removing cholesterol from macrophages and by exerting antioxidant and anti-inflammatory effects. Oxidation is thought to impair HDL functions, yet certain oxidative modifications may be advantageous; thus, mild oxidation reportedly enhances cell cholesterol uptake by HDL whereas extensive oxidation impairs it. To elucidate the underlying energetic and structural basis, we analyzed the effects of copper and hypochlorite (which preferentially oxidize lipids and proteins, respectively) on thermal stability of plasma spherical HDL. Circular dichroism, light scattering, calorimetry, gel electrophoresis, and electron microscopy showed that mild oxidation destabilizes HDL and accelerates protein dissociation and lipoprotein fusion, while extensive oxidation inhibits these reactions; this inhibition correlates with massive protein cross-linking and with lipolysis. We propose that mild oxidation lowers kinetic barriers for HDL remodeling due to diminished apolipoprotein affinity for lipids resulting from oxidation of methionine and aromatic residues in apolipoproteins A-I and A-II followed by protein cross-linking into dimers and/or trimers. In contrast, advanced oxidation inhibits protein dissociation and HDL fusion due to lipid redistribution from core to surface upon lipolysis and to massive protein cross-linking. Our results help reconcile the apparent controversy in the studies of oxidized HDL and suggest that mild oxidation may benefit HDL functions.

  1. Impact of leachate composition on the advanced oxidation treatment.

    PubMed

    Oulego, Paula; Collado, Sergio; Laca, Adriana; Díaz, Mario

    2016-01-01

    Advanced oxidation processes (AOPs) are gaining importance as an alternative to the biological or physicochemical treatments for the management of leachates. In this work, it has been studied the effect of the characteristics of the leachate (content in humic acids, landfill age and degree of stabilization) on the wet oxidation process and final quality of the treated effluent. A high concentration of humic acids in the leachate had a positive effect on the COD removal because this fraction is more easily oxidizable. Additionally, it has been demonstrated that the simultaneous presence of humic acid and the intermediates generated during the oxidation process improved the degradation of this acid, since such intermediates are stronger initiators of free radicals than the humic acid itself. Similar values of COD removals (49% and 51%) and biodegradability indices (0.30 and 0.35) were observed, after 8 h of wet oxidation, for the stabilised leachate (biologically pretreated) and the raw one, respectively. Nevertheless, final colour removal was much higher for the stabilised leachate, achieving values up to 91%, whereas for the raw one only 56% removal was attained for the same reaction time. Besides, wet oxidation treatment was more efficient for the young leachate than for the old one, with final COD conversions of 60% and 37%, respectively. Eventually, a triangular "three-lump" kinetic model, which considered direct oxidation to CO2 and partial oxidation through intermediate compounds, was here proposed.

  2. Terahertz-Driven Nonlinear Spin Response of Antiferromagnetic Nickel Oxide

    NASA Astrophysics Data System (ADS)

    Baierl, S.; Mentink, J. H.; Hohenleutner, M.; Braun, L.; Do, T.-M.; Lange, C.; Sell, A.; Fiebig, M.; Woltersdorf, G.; Kampfrath, T.; Huber, R.

    2016-11-01

    Terahertz magnetic fields with amplitudes of up to 0.4 Tesla drive magnon resonances in nickel oxide while the induced dynamics is recorded by femtosecond magneto-optical probing. We observe distinct spin-mediated optical nonlinearities, including oscillations at the second harmonic of the 1 THz magnon mode. The latter originate from coherent dynamics of the longitudinal component of the antiferromagnetic order parameter, which are probed by magneto-optical effects of second order in the spin deflection. These observations allow us to dynamically disentangle electronic from lattice-related contributions to magnetic linear birefringence and dichroism—information so far only accessible by ultrafast THz spin control. The nonlinearities discussed here foreshadow physics that will become essential in future subcycle spin switching.

  3. Liquid crystallinity driven highly aligned large graphene oxide composites

    NASA Astrophysics Data System (ADS)

    Lee, Kyung Eun; Oh, Jung Jae; Yun, Taeyeong; Kim, Sang Ouk

    2015-04-01

    Graphene is an emerging graphitic carbon materials, consisting of sp2 hybridized two dimensinal honeycomb structure. It has been widely studied to incorporate graphene with polymer to utilize unique property of graphene and reinforce electrical, mechanical and thermal property of polymer. In composite materials, orientation control of graphene significantly influences the property of composite. Until now, a few method has been developed for orientation control of graphene within polymer matrix. Here, we demonstrate facile fabrication of high aligned large graphene oxide (LGO) composites in polydimethylsiloxane (PDMS) matrix exploiting liquid crystallinity. Liquid crystalline aqueous dispersion of LGO is parallel oriented within flat confinement geometry. Freeze-drying of the aligned LGO dispersion and subsequent infiltration with PDMS produce highly aligned LGO/PDMS composites. Owing to the large shape anisotropy of LGO, liquid crystalline alignment occurred at low concentration of 2 mg/ml in aqueous dispersion, which leads to the 0.2 wt% LGO loaded composites.

  4. Light-driven oxidation of polysaccharides by photosynthetic pigments and a metalloenzyme.

    PubMed

    Cannella, D; Möllers, K B; Frigaard, N-U; Jensen, P E; Bjerrum, M J; Johansen, K S; Felby, C

    2016-04-04

    Oxidative processes are essential for the degradation of plant biomass. A class of powerful and widely distributed oxidative enzymes, the lytic polysaccharide monooxygenases (LPMOs), oxidize the most recalcitrant polysaccharides and require extracellular electron donors. Here we investigated the effect of using excited photosynthetic pigments as electron donors. LPMOs combined with pigments and reducing agents were exposed to light, which resulted in a never before seen 100-fold increase in catalytic activity. In addition, LPMO substrate specificity was broadened to include both cellulose and hemicellulose. LPMO enzymes and pigment derivatives common in the environment of plant-degrading organisms thus form a highly reactive and stable light-driven system increasing the turnover rate and versatility of LPMOs. This light-driven system may find applications in biotechnology and chemical processing.

  5. Light-driven oxidation of polysaccharides by photosynthetic pigments and a metalloenzyme

    PubMed Central

    Cannella, D.; Möllers, K. B.; Frigaard, N.-U.; Jensen, P. E.; Bjerrum, M. J.; Johansen, K. S.; Felby, C.

    2016-01-01

    Oxidative processes are essential for the degradation of plant biomass. A class of powerful and widely distributed oxidative enzymes, the lytic polysaccharide monooxygenases (LPMOs), oxidize the most recalcitrant polysaccharides and require extracellular electron donors. Here we investigated the effect of using excited photosynthetic pigments as electron donors. LPMOs combined with pigments and reducing agents were exposed to light, which resulted in a never before seen 100-fold increase in catalytic activity. In addition, LPMO substrate specificity was broadened to include both cellulose and hemicellulose. LPMO enzymes and pigment derivatives common in the environment of plant-degrading organisms thus form a highly reactive and stable light-driven system increasing the turnover rate and versatility of LPMOs. This light-driven system may find applications in biotechnology and chemical processing. PMID:27041218

  6. Insights on slab-driven mantle flow from advances in three-dimensional modelling

    NASA Astrophysics Data System (ADS)

    Jadamec, Margarete A.

    2016-10-01

    The wealth of seismic observations collected over the past 20 years has raised intriguing questions about the three-dimensional (3D) nature of the mantle flow field close to subduction zones and provided a valuable constraint for how the plate geometry may influence mantle flow proximal to the slab. In geodynamics, there has been a new direction of subduction zone modelling that has explored the 3D nature of slab-driven mantle flow, motivated in part by the observations from shear wave splitting, but also by the observed variations in slab geometries worldwide. Advances in high-performance computing are now allowing for an unprecedented level of detail to be incorporated into numerical models of subduction. This paper summarizes recent advances from 3D geodynamic models that reveal the complex nature of slab-driven mantle flow, including trench parallel flow, toroidal flow around slab edges, mantle upwelling at lateral slab edges, and small scale convection within the mantle wedge. This implies slab-driven mantle deformation zones occur in the asthenosphere proximal to the slab, wherein the mantle may commonly flow in a different direction and rate than the surface plates, implying laterally variable plate-mantle coupling. The 3D slab-driven mantle flow can explain, in part, the lateral transport of geochemical signatures in subduction zones. In addition, high-resolution geographically referenced models can inform the interpretation of slab structure, where seismic data are lacking. The incorporation of complex plate boundaries into high-resolution, 3D numerical models opens the door to a new avenue of research in model construction, data assimilation, and modelling workflows, and gives 3D immersive visualization a new role in scientific discovery.

  7. Advanced treatment of sodium acetate in water by ozone oxidation.

    PubMed

    Yang, De-Min; Yuan, Jian-Mei

    2014-02-01

    Ozone oxidation is an advanced oxidation process for treatment of organic and inorganic wastewater. In this paper, sodium acetate (according to chemical oxygen demand [COD]) was selected as the model pollutant in water, and the degradation efficiencies and mechanism of sodium acetate in water by ozone oxidation were investigated. The results showed that the ozone oxidation was an effective treatment technology for advanced treatment of sodium acetate in water; the COD removal rate obtained the maximum value of 45.89% from sodium acetate solution when the pH value was 10.82, ozone concentration was 100 mg/L, reaction time was 30 minutes, and reaction temperature was 25 degrees C. The COD removal rate increased first and decreased subsequently with the bicarbonate (HCO3-) concentration from 0 to 200 mg/L, the largest decline being 20.35%. The COD removal rate declined by 25.38% with the carbonate (CO3(2-)) concentration from 0 to 200 mg/L; CO3(2-) has a more obvious scavenging effect to inhibit the formation of hydroxyl free radicals than HCO3-. Calcium chloride (CaCl2) and calcium hydroxide (Ca(OH)2) could enhance the COD removal rate greatly; they could reach 77.35 and 96.53%, respectively, after a reaction time of 30 minutes, which was increased by 31.46 and 50.64%, respectively, compared with only ozone oxidation. It was proved that the main ozone oxidation product of sodium acetate was carbon dioxide (CO2), and the degradation of sodium acetate in the ozone oxidation process followed the mechanism of hydroxyl free radicals.

  8. Liquid crystallinity driven highly aligned large graphene oxide composites

    SciTech Connect

    Lee, Kyung Eun; Oh, Jung Jae; Yun, Taeyeong; Kim, Sang Ouk

    2015-04-15

    Graphene is an emerging graphitic carbon materials, consisting of sp{sup 2} hybridized two dimensinal honeycomb structure. It has been widely studied to incorporate graphene with polymer to utilize unique property of graphene and reinforce electrical, mechanical and thermal property of polymer. In composite materials, orientation control of graphene significantly influences the property of composite. Until now, a few method has been developed for orientation control of graphene within polymer matrix. Here, we demonstrate facile fabrication of high aligned large graphene oxide (LGO) composites in polydimethylsiloxane (PDMS) matrix exploiting liquid crystallinity. Liquid crystalline aqueous dispersion of LGO is parallel oriented within flat confinement geometry. Freeze-drying of the aligned LGO dispersion and subsequent infiltration with PDMS produce highly aligned LGO/PDMS composites. Owing to the large shape anisotropy of LGO, liquid crystalline alignment occurred at low concentration of 2 mg/ml in aqueous dispersion, which leads to the 0.2 wt% LGO loaded composites. - Graphical abstract: Liquid crystalline LGO aqueous dispersions are spontaneous parallel aligned between geometric confinement for highly aligned LGO/polymer composite fabrication. - Highlights: • A simple fabrication method for highly aligned LGO/PDMS composites is proposed. • LGO aqueous dispersion shows nematic liquid crystalline phase at 0.8 mg/ml. • In nematic phase, LGO flakes are highly aligned by geometric confinement. • Infiltration of PDMS into freeze-dried LGO allows highly aligned LGO/PDMS composites.

  9. Biologically templated photocatalytic nanostructures for sustained light-driven water oxidation

    NASA Astrophysics Data System (ADS)

    Nam, Yoon Sung; Magyar, Andrew P.; Lee, Daeyeon; Kim, Jin-Woong; Yun, Dong Soo; Park, Heechul; Pollom, Thomas S.; Weitz, David A.; Belcher, Angela M.

    2010-05-01

    Over several billion years, cyanobacteria and plants have evolved highly organized photosynthetic systems to shuttle both electronic and chemical species for the efficient oxidation of water. In a similar manner to reaction centres in natural photosystems, molecular and metal oxide catalysts have been used to photochemically oxidize water. However, the various approaches involving the molecular design of ligands, surface modification and immobilization still have limitations in terms of catalytic efficiency and sustainability. Here, we demonstrate a biologically templated nanostructure for visible light-driven water oxidation that uses a genetically engineered M13 virus scaffold to mediate the co-assembly of zinc porphyrins (photosensitizer) and iridium oxide hydrosol clusters (catalyst). Porous polymer microgels are used as an immobilization matrix to improve the structural durability of the assembled nanostructures and to allow the materials to be recycled. Our results suggest that the biotemplated nanoscale assembly of functional components is a promising route to significantly improved photocatalytic water-splitting systems.

  10. Evaluation of advanced oxidation process for the treatment of groundwater

    SciTech Connect

    Garland, S.B. II ); Peyton, G.R. ); Rice, L.E. . Kansas City Div.)

    1990-01-01

    An advanced oxidation process utilizing ozone, ultraviolet radiation, and hydrogen peroxide was selected for the removal of chlorinated hydrocarbons, particularly trichlorethene and 1,2-dichlorethene, from groundwater underlying the US Department of Energy Kansas City Plant. Since the performance of this process for the removal of organics from groundwater is not well-documented, an evaluation was initiated to determine the performance of the treatment plant, document the operation and maintenance costs experience, and evaluate contaminant removal mechanisms. 11 refs., 3 figs.

  11. Increased Hepatic Fatty Acids Uptake and Oxidation by LRPPRC-Driven Oxidative Phosphorylation Reduces Blood Lipid Levels

    PubMed Central

    Lei, Shi; Sun, Run-zhu; Wang, Di; Gong, Mei-zhen; Su, Xiang-ping; Yi, Fei; Peng, Zheng-wu

    2016-01-01

    Hyperlipidemia is one of the major risk factors of atherosclerosis and other cardiovascular diseases. This study aimed to investigate the impact of leucine rich pentatricopeptide repeat containing protein (LRPPRC)-driven hepatic oxidative phoshorylation on blood lipid levels. The hepatic LRPPRC level was modulated by liver-specific transgenic or adeno-associated virus 8 carried shRNA targeting Lrpprc (aav-shLrpprc). Mice were fed with a high fat diet to induce obesity. Gene expression was analyzed by quantitative real-time PCR and / or western blot. The hepatic ATP level, hepatic and serum lipids contents, and mitochondria oxidative phosphorylation (OxPhos) complex activities were measured using specific assay kits. The uptake and oxidation of fatty acid by hepatocytes were assessed using 14C-palmitate. LRPPRC regulated the expression of genes encoded by mitochondrial genome but not those by nuclear genome involved in mitochondria biogenesis, OxPhos, and lipid metabolism. Increased OxPhos in liver mediated by LRPPRC resulted in the increase of hepatic ATP level. Lrpprc promoted palmitate uptake and oxidation by hypatocytes. The hepatic and serum triglyceride and total cholesterol levels were inversely associated with the hepatic LRPPRC level. These data demonstrated that LRPPRC-driven hepatic OxPhos could promote fatty acids uptake and oxidation by hepatocytes and reduce both hepatic and circulating triglyceride and cholesterol levels. PMID:27462273

  12. Electrochemical advanced oxidation processes: today and tomorrow. A review.

    PubMed

    Sirés, Ignasi; Brillas, Enric; Oturan, Mehmet A; Rodrigo, Manuel A; Panizza, Marco

    2014-01-01

    In recent years, new advanced oxidation processes based on the electrochemical technology, the so-called electrochemical advanced oxidation processes (EAOPs), have been developed for the prevention and remediation of environmental pollution, especially focusing on water streams. These methods are based on the electrochemical generation of a very powerful oxidizing agent, such as the hydroxyl radical ((•)OH) in solution, which is then able to destroy organics up to their mineralization. EAOPs include heterogeneous processes like anodic oxidation and photoelectrocatalysis methods, in which (•)OH are generated at the anode surface either electrochemically or photochemically, and homogeneous processes like electro-Fenton, photoelectro-Fenton, and sonoelectrolysis, in which (•)OH are produced in the bulk solution. This paper presents a general overview of the application of EAOPs on the removal of aqueous organic pollutants, first reviewing the most recent works and then looking to the future. A global perspective on the fundamentals and experimental setups is offered, and laboratory-scale and pilot-scale experiments are examined and discussed.

  13. Alloys for advanced steam turbines--Oxidation behavior

    SciTech Connect

    Holcomb, G.R.

    2007-10-01

    Advanced or ultra supercritical (USC) steam power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy (DOE) include power generation from coal at 60% efficiency, which would require steam temperatures of up to 760°C. Current research on the oxidation of candidate materials for advanced steam turbines is presented with a focus on a methodology for estimating chromium evaporation rates from protective chromia scales. The high velocities and pressures of advanced steam turbines lead to evaporation predictions as high as 5 × 10-8 kg m-2s-1 of CrO2(OH)2(g) at 760°C and 34.5 MPa. This is equivalent to 0.077 mm per year of solid Cr loss.

  14. Trace element cycling through iron oxide minerals during redox-driven dynamic recrystallization

    SciTech Connect

    Frierdich, Andrew J.; Luo, Yun; Catalano, Jeffrey G.

    2011-11-17

    Microbially driven iron redox cycling in soil and sedimentary systems, including during diagenesis and fluid migration, may activate secondary abiotic reactions between aqueous Fe(II) and solid Fe(III) oxides. These reactions catalyze dynamic recrystallization of iron oxide minerals through localized and simultaneous oxidative adsorption of Fe(II) and reductive dissolution of Fe(III). Redox-active trace elements undergo speciation changes during this process, but the impact redox-driven recrystallization has on redox-inactive trace elements associated with iron oxides is uncertain. Here we demonstrate that Ni is cycled through the minerals goethite and hematite during redox-driven recrystallization. X-ray absorption spectroscopy demonstrates that during this process adsorbed Ni becomes progressively incorporated into the minerals. Kinetic studies using batch reactors containing aqueous Fe(II) and Ni preincorporated into iron oxides display substantial release of Ni to solution. We conclude that iron oxide recrystallization activated by aqueous Fe(II) induces cycling of Ni through the mineral structure, with adsorbed Ni overgrown in regions of Fe(II) oxidative adsorption and incorporated Ni released in regions of reductive dissolution of structural Fe(III). The redistribution of Ni among the mineral bulk, mineral surface, and aqueous solution appears to be thermodynamically controlled and catalyzed by Fe(II). Our work suggests that important proxies for ocean composition on the early Earth may be invalid, identifies new processes controlling micronutrient availability in soil, sedimentary, and aquatic ecosystems, and points toward a mechanism for trace element mobilization during diagenesis and enrichment in geologic fluids.

  15. FPIC: A Key Next Step for Stability Studies of Advanced Beam Driven FRCs

    NASA Astrophysics Data System (ADS)

    Dettrick, Sean; Barnes, Dan; Ceccherini, Francesco; Galeotti, Laura; Guerrero, Victor; Hendrix, Doug; Hubbard, Kevin; Milroy, Richard; Necas, Ales; TAE Team

    2015-11-01

    The goal of the C-2U experiment is to use neutral beam heating and edge biasing to sustain an advanced beam-driven FRC for many milliseconds, longer than the growth times of known instabilities and the resistive wall time. To guide the experiment further into unexplored parameter regimes, it is desirable to have a stability code suitable for beam-driven FRC plasmas, in which the bulk of ion orbits are not Larmor-like and hence gyrokinetic approximations are inapplicable. Fully kinetic ions are required for stability simulations of beam driven FRCs, as are multiple ion species, end boundary conditions, and a resistive boundary. To meet these challenges a new 3D quasineutral hybrid code, FPIC, is being developed. FPIC has a choice of zero electron mass and finite electron mass Ohm's law solvers. Uniform staggered grids, finite differencing, and cut cell boundaries are used to simplify and optimize the PIC while allowing arbitrary boundary shapes. Finite resistivity of the boundary is implemented by coupling free-space exterior solutions to the cut-cell edges. The code is MPI parallelized and the particle push is GPU accelerated. Code benchmarks will be presented including the stability of the FRC tilt mode.

  16. Advanced oxidation of alkylphenol ethoxylates in aqueous systems.

    PubMed

    Nagarnaik, Pranav M; Boulanger, Bryan

    2011-10-01

    Alkylphenols and alkylphenol ethoxylates are ubiquitous wastewater contaminants. In this study the oxidation of nonylphenol ethoxylates (NPEO) and octylphenol ethoxylates (OPEO) by oxidant systems generating hydroxide radicals was evaluated. The reaction of each oxidant with a technical mixture of NPEO (Tergitol™) and OPEO (Triton X-100™) in ultrapure laboratory water and four aqueous environmental matrices was carried out in order to develop an understanding of reaction kinetics. The oxidation of APEOs was evaluated by hydroxyl radical generated by (1) hydrogen peroxide in the presence of ultraviolet light, (2) Fenton's reagent, and (3) a photo-Fenton's process. The second order kinetic rate constant for both NPEO and OPEO with hydroxyl radical was calculated to be 1.1×10¹⁰ M⁻¹ s⁻¹. The efficacy of the AOPs within an aqueous environmental matrix was dependent on the rate of formation of hydroxyl radical and the scavenging capacity of the matrix. A model based on the hydroxyl radical formation, scavenging capacity and the kinetic rate constant of target APEO was developed from the existing literature and applied to predict the concentration of APEOs in solution during advanced oxidation in different aqueous environmental matrices. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Mineralization of the biocide chloroxylenol by electrochemical advanced oxidation processes.

    PubMed

    Skoumal, Marcel; Arias, Conchita; Cabot, Pere Lluís; Centellas, Francesc; Garrido, José Antonio; Rodríguez, Rosa María; Brillas, Enric

    2008-04-01

    Electrochemical advanced oxidation processes (EAOPs) are environmentally friendly methods based on the destruction of organic pollutants in wastewaters with in situ electrogenerated hydroxyl radical. This species is formed in anodic oxidation (AO) from water oxidation at the anode and in indirect electro-oxidation methods like electro-Fenton (EF) and photoelectro-Fenton (PEF) also from reaction between catalytic Fe2+ and H2O2 continuously produced at the O2-diffusion cathode. The PEF method involves the irradiation of the treated solution with UVA light to enhance the photolysis of organics including Fe(III) complexes. In this work, the oxidation power of such EAOPs to decontaminate synthetic wastewaters of the biocide chloroxylenol (4-chloro-3,5-dimethylphenol) at pH 3.0 is comparatively examined with an undivided electrolytic cell containing a Pt or boron-doped diamond (BDD) anode and a stainless steel or O2-diffusion cathode. The initial chlorine is released as Cl(-) ion, which remains stable in the medium using Pt or is oxidized to Cl2 on BDD. The biocide solutions can be completely decontaminated using AO with a BDD anode, as well as PEF with a Pt or BDD anode. The PEF procedure with a BDD anode is the most powerful method leading to total mineralization in about 300 min, practically independent of current density. When current density rises, the degradation rate of processes increases, but they become less efficient due to the larger enhancement of waste reactions of oxidants. Chloroxylenol is much more rapidly removed in EF and PEF than in AO. 2,6-dimethylhydroquinone, 2,6-dimethyl-p-benzoquinone and 3,5-dimethyl-2-hydroxy-p-benzoquinone are identified as aromatic by-products, and maleic, malonic, pyruvic, acetic and oxalic acids are found as generated carboxylic acids. A general pathway for chloroxylenol mineralization by all EAOPs including the above by-products is proposed.

  18. Colloidal metal oxide nanocrystal catalysis by sustained chemically driven ligand displacement.

    PubMed

    De Roo, Jonathan; Van Driessche, Isabel; Martins, José C; Hens, Zeger

    2016-05-01

    Surface chemistry is a key enabler for colloidal nanocrystal applications. In this respect, metal oxide nanocrystals (NCs) stand out from other NCs as carboxylic acid ligands adsorb on their surface by dissociation to carboxylates and protons, the latter proving essential in electron transfer reactions. Here, we show that this binding motif sets the stage for chemically driven ligand displacement where the binding of amines or alcohols to HfO2 NCs is promoted by the conversion of a bound carboxylic acid into a non-coordinating amide or ester. Furthermore, the sustained ligand displacement, following the addition of excess carboxylic acid, provides a catalytic pathway for ester formation, whereas the addition of esters leads to NC-catalysed transesterification. Because sustained, chemically driven ligand displacement leaves the NCs-including their surface composition-unchanged and preserves colloidal stability, metal oxide nanocrystals are thus turned into effective nanocatalysts that bypass the tradeoff between colloidal stability and catalytic activity.

  19. Colloidal metal oxide nanocrystal catalysis by sustained chemically driven ligand displacement

    NASA Astrophysics Data System (ADS)

    de Roo, Jonathan; van Driessche, Isabel; Martins, José C.; Hens, Zeger

    2016-05-01

    Surface chemistry is a key enabler for colloidal nanocrystal applications. In this respect, metal oxide nanocrystals (NCs) stand out from other NCs as carboxylic acid ligands adsorb on their surface by dissociation to carboxylates and protons, the latter proving essential in electron transfer reactions. Here, we show that this binding motif sets the stage for chemically driven ligand displacement where the binding of amines or alcohols to HfO2 NCs is promoted by the conversion of a bound carboxylic acid into a non-coordinating amide or ester. Furthermore, the sustained ligand displacement, following the addition of excess carboxylic acid, provides a catalytic pathway for ester formation, whereas the addition of esters leads to NC-catalysed transesterification. Because sustained, chemically driven ligand displacement leaves the NCs--including their surface composition--unchanged and preserves colloidal stability, metal oxide nanocrystals are thus turned into effective nanocatalysts that bypass the tradeoff between colloidal stability and catalytic activity.

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

    PubMed

    Sun, Ke; Saadi, Fadl H; Lichterman, Michael F; Hale, William G; Wang, Hsin-Ping; Zhou, Xinghao; Plymale, Noah T; Omelchenko, Stefan T; He, Jr-Hau; Papadantonakis, Kimberly M; Brunschwig, Bruce S; Lewis, Nathan S

    2015-03-24

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

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

    DOE PAGES

    Sun, Ke; Saadi, Fadl H.; Lichterman, Michael F.; ...

    2015-03-11

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

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

    PubMed Central

    Sun, Ke; Saadi, Fadl H.; Lichterman, Michael F.; Hale, William G.; Wang, Hsin-Ping; Zhou, Xinghao; Plymale, Noah T.; Omelchenko, Stefan T.; He, Jr-Hau; Papadantonakis, Kimberly M.; Brunschwig, Bruce S.; Lewis, Nathan S.

    2015-01-01

    Reactively sputtered nickel oxide (NiOx) films provide transparent, antireflective, electrically conductive, chemically stable coatings that also are highly active electrocatalysts for the oxidation of water to O2(g). These NiOx coatings provide protective layers on a variety of technologically important semiconducting photoanodes, including textured crystalline Si passivated by amorphous silicon, crystalline n-type cadmium telluride, and hydrogenated amorphous silicon. Under anodic operation in 1.0 M aqueous potassium hydroxide (pH 14) in the presence of simulated sunlight, the NiOx films stabilized all of these self-passivating, high-efficiency semiconducting photoelectrodes for >100 h of sustained, quantitative solar-driven oxidation of water to O2(g). PMID:25762067

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

    PubMed

    Rastgar, Shokoufeh; Pilarski, Martin; Wittstock, Gunther

    2016-09-15

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

  4. Homogenous and heterogenous advanced oxidation of two commercial reactive dyes.

    PubMed

    Balcioglu, I A; Arslan, I; Sacan, M T

    2001-07-01

    Two commercial reactive dyes, the azo dye Reactive Black 5 and the copper phythalocyanine dye Reactive Blue 21, have been treated at a concentration of 75 mg l(-1) by titanium dioxide mediated photocatalytic (TiO2/UV), dark and UV-light assisted Fenton (Fe2+/H2O2) and Fenton-like (Fe3+/H2O2) processes in acidic medium. For the treatment of Reactive Black 5, all investigated advanced oxidation processes were quite effective in terms of colour, COD as well as TOC removal. Moreover, the relative growth inhibition of the azo dye towards the marine algae Dunaliella tertiolecta that was initially 70%, did not exhibit an increase during the studied advanced oxidation reactions and complete detoxification at the end of the treatment period could be achieved for all investigated treatment processes. However, for Reactive Blue 21, abatement in COD and UV-VIS absorbance values was mainly due to the adsorption of the dye on the photocatalyst surface and/or the coagulative effect of Fe3+/Fe2+ ions. Although only a limited fraction of the copper phythalocyanine dye underwent oxidative degradation, 47% of the total copper in the dye was already released after 1 h photocatalytic treatment.

  5. Nanophase transition metal oxides show large thermodynamically driven shifts in oxidation-reduction equilibria.

    PubMed

    Navrotsky, Alexandra; Ma, Chengcheng; Lilova, Kristina; Birkner, Nancy

    2010-10-08

    Knowing the thermodynamic stability of transition metal oxide nanoparticles is important for understanding and controlling their role in a variety of industrial and environmental systems. Using calorimetric data on surface energies for cobalt, iron, manganese, and nickel oxide systems, we show that surface energy strongly influences their redox equilibria and phase stability. Spinels (M(3)O(4)) commonly have lower surface energies than metals (M), rocksalt oxides (MO), and trivalent oxides (M(2)O(3)) of the same metal; thus, the contraction of the stability field of the divalent oxide and expansion of the spinel field appear to be general phenomena. Using tabulated thermodynamic data for bulk phases to calculate redox phase equilibria at the nanoscale can lead to errors of several orders of magnitude in oxygen fugacity and of 100 to 200 kelvin in temperature.

  6. Degradation of wine industry wastewaters by photocatalytic advanced oxidation.

    PubMed

    Navarro, P; Sarasa, J; Sierra, D; Esteban, S; Ovelleiro, J L

    2005-01-01

    Wine industry wastewaters contain a high concentration of organic biodegradable compounds as well as a great amount of suspended solids. These waters are difficult to treat by conventional biological processes because they are seasonal and a great flow variation exists. Photocatalytic advanced oxidation is a promising technology for waters containing high amounts of organic matter. In this study we firstly investigated the application of H2O2 as oxidant combined with light (artificial or natural) in order to reduce the organic matter in samples from wine industry effluents. Secondly, we studied its combination with heterogeneous catalysts: titanium dioxide and clays containing iron minerals. The addition of photocatalysts to the system reduces the required H2O2 concentration. Although the H2O2/TiO2 system produces higher efficiencies, the H2O2/clays system requires a H2O2 dosage between three and six times lower.

  7. Comparison of different advanced oxidation processes for phenol degradation.

    PubMed

    Esplugas, Santiago; Giménez, Jaime; Contreras, Sandra; Pascual, Esther; Rodríguez, Miguel

    2002-02-01

    Advanced Oxidation Processes (O3, O3/H2O2, UV, UV/O3, UV/H2O2, O3/UV/H2O2, Fe2+ /H2O2 and photocatalysis) for degradation of phenol in aqueous solution have been studied in earlier works. In this paper, a comparison of these techniques is undertaken: pH influence, kinetic constants, stoichiometric coefficient and optimum oxidant/pollutant ratio. Of the tested processes, Fenton reagent was found to the fastest one for phenol degradation. However, lower costs were obtained with ozonation. In the ozone combinations, the best results were achieved with single ozonation. As for the UV processes, UV/H2O2 showed the highest degradation rate.

  8. Advanced oxidation processes in azo dye wastewater treatment.

    PubMed

    Papić, Sanja; Koprivanac, Natalija; Bozić, Ana Loncarić; Vujević, Dinko; Dragicević, Savka Kusar; Kusić, Hrvoje; Peternel, Igor

    2006-06-01

    The chemical degradation of synthetic azo dyes color index (C.I.) Acid Orange 7, C.I. Direct Orange 39, and C.I. Mordant Yellow 10 has been studied by the following advanced oxidation processes: Fenton, Fenton-like, ozonation, peroxone without or with addition of solid particles, zeolites HY, and NH4ZSM5. Spectrophotometric (UV/visible light spectrum) and total organic carbon measurements were used for determination of process efficiency and reaction kinetics. The degradation rates are evaluated by determining their rate constants. The different hydroxyl radical generation processes were comparatively studied, and the most efficient experimental conditions for the degradation of organic azo dyes solutions were determined.

  9. Computational Fluid Dynamics Simulation of Flows in an Oxidation Ditch Driven by a New Surface Aerator.

    PubMed

    Huang, Weidong; Li, Kun; Wang, Gan; Wang, Yingzhe

    2013-11-01

    In this article, we present a newly designed inverse umbrella surface aerator, and tested its performance in driving flow of an oxidation ditch. Results show that it has a better performance in driving the oxidation ditch than the original one with higher average velocity and more uniform flow field. We also present a computational fluid dynamics model for predicting the flow field in an oxidation ditch driven by a surface aerator. The improved momentum source term approach to simulate the flow field of the oxidation ditch driven by an inverse umbrella surface aerator was developed and validated through experiments. Four kinds of turbulent models were investigated with the approach, including the standard k-ɛ model, RNG k-ɛ model, realizable k-ɛ model, and Reynolds stress model, and the predicted data were compared with those calculated with the multiple rotating reference frame approach (MRF) and sliding mesh approach (SM). Results of the momentum source term approach are in good agreement with the experimental data, and its prediction accuracy is better than MRF, close to SM. It is also found that the momentum source term approach has lower computational expenses, is simpler to preprocess, and is easier to use.

  10. Observation of Energetic Particle Driven Modes Relevant to Advanced Tokamak Regimes

    SciTech Connect

    R. Nazikian; B. Alper; H.L. Berk; D. Borba; C. Boswell; R.V. Budny; K.H. Burrell; C.Z. Cheng; E.J. Doyle; E. Edlund; R.J. Fonck; A. Fukuyama; N.N. Gorelenkov; C.M. Greenfield; D.J. Gupta; M. Ishikawa; R.J. Jayakumar; G.J. Kramer; Y. Kusama; R.J. La Haye; G.R. McKee; W.A. Peebles; S.D. Pinches; M. Porkolab; J. Rapp; T.L. Rhodes; S.E. Sharapov; K. Shinohara; J.A. Snipes; W.M. Solomon; E.J. Strait; M. Takechi; M.A. Van Zeeland; W.P. West; K.L. Wong; S. Wukitch; L. Zeng

    2004-10-21

    Measurements of high-frequency oscillations in JET [Joint European Torus], JT-60U, Alcator C-Mod, DIII-D, and TFTR [Tokamak Fusion Test Reactor] plasmas are contributing to a new understanding of fast ion-driven instabilities relevant to Advanced Tokamak (AT) regimes. A model based on the transition from a cylindrical-like frequency-chirping mode to the Toroidal Alfven Eigenmode (TAE) has successfully encompassed many of the characteristics seen in experiments. In a surprising development, the use of internal density fluctuation diagnostics has revealed many more modes than has been detected on edge magnetic probes. A corollary discovery is the observation of modes excited by fast particles traveling well below the Alfven velocity. These observations open up new opportunities for investigating a ''sea of Alfven Eigenmodes'' in present-scale experiments, and highlight the need for core fluctuation and fast ion measurements in a future burning-plasma experiment.

  11. Efficient Light-Driven Water Oxidation Catalysis by Dinuclear Ruthenium Complexes.

    PubMed

    Berardi, Serena; Francàs, Laia; Neudeck, Sven; Maji, Somnath; Benet-Buchholz, Jordi; Meyer, Franc; Llobet, Antoni

    2015-11-01

    Mastering the light-induced four-electron oxidation of water to molecular oxygen is a key step towards the achievement of overall water splitting to produce alternative solar fuels. In this work, we report two rugged molecular pyrazolate-based diruthenium complexes that efficiently catalyze visible-light-driven water oxidation. These complexes were fully characterized both in the solid state (by X-ray diffraction analysis) and in solution (spectroscopically and electrochemically). Benchmark performances for homogeneous oxygen production have been obtained for both catalysts in the presence of a photosensitizer and a sacrificial electron acceptor at pH 7, and a turnover frequency of up to 11.1 s(-1) and a turnover number of 5300 were obtained after three successive catalytic runs. Under the same experimental conditions with the same setup, the pyrazolate-based diruthenium complexes outperform other well-known water oxidation catalysts owing to both electrochemical and mechanistic aspects.

  12. Sewage sludge treatment using microwave-enhanced advanced oxidation process.

    PubMed

    Yin, Gui Q; Liao, Ping H; Lo, Kwang V

    2008-02-01

    A microwave-enhanced advanced oxidation process using hydrogen peroxide (MW/H(2)O(2)-AOP) was used for the release of nutrients and the destruction of solids from secondary municipal sewage sludge in this study. Using a computer statistical software package for designing experiments and for data analyses, four factors including microwave heating temperature, heating time, hydrogen peroxide dosage, and sludge solids content were examined. Experiments were performed at sludge solids content of 0.5, 1.5 and 2.5%, heating temperature of 80, 100 and 120 degrees C, heating time of 1.5, 3 and 9 minutes, and hydrogen peroxide dosage of 0, 1 and 2 wt %, respectively. Overall, the maximum solubilization of nutrients was obtained at 2.5% of total solids content, 2 wt % of hydrogen peroxide, 5 min. of microwave heating and at 120 degrees C. The most significant factor for the solubilization of nutrients using the microwave enhanced advanced oxidation process was the initial sludge concentration. Hydrogen peroxide dosage was also a very significant factor. The maximum yield occurred at an extended heating period of five minutes in this study. Nevertheless, the results indicated that the nutrient release and disintegration of solids were also very substantial over heating periods of 1.5 and 3 minutes. Even with a heating period of 1.5 minutes, the yield was estimated to be about 70% that of the 5 minute heating.

  13. Performance of advanced oxide fuel pins in EBR-II

    SciTech Connect

    Lawrence, L.A.; Jensen, S.M.; Hales, J.W.; Karnesky, R.A.; Makenas, B.J.

    1986-05-01

    The effects of design and operating parameters on mixed-oxide fuel pin irradiation performance were established for the Hanford Engineering Development Laboratory (HEDL) advanced oxide EBR-II test series. Fourteen fuel pins breached in-reactor with reference 316 SS cladding. Seven of the breaches are attributed to FCMI. Of the remaining seven breached pins, three are attributed to local cladding over-temperatures similar to the breach mechanism for the reference oxide pins irradiated in EBR-II. FCCI was found to be a contributing factor in two high burnup, i.e., 11.7 at. % breaches. The remaining two breaches were attributed to mechanical interaction of UO/sub 2/ fuel and fission products accumulated in the lower cladding insulator gap, and a loss of cladding ductility possibly due to liquid metal embrittlement. Fuel smear density appears to have the most significant impact on lifetime. Quantitative evaluations of cladding diameter increases attributed to FCMI, established fuel smear density, burnup, and cladding thickness-to-diameter ratio as the major parameters influencing the extent of cladding strain.

  14. Hydrothermal fabrication of selectively doped organic assisted advanced ZnO nanomaterial for solar driven photocatalysis.

    PubMed

    Namratha, K; Byrappa, K; Byrappa, S; Venkateswarlu, P; Rajasekhar, D; Deepthi, B K

    2015-08-01

    Hydrothermal fabrication of selectively doped (Ag(+)+Pd(3+)) advanced ZnO nanomaterial has been carried out under mild pressure temperature conditions (autogeneous; 150°C). Gluconic acid has been used as a surface modifier to effectively control the particle size and morphology of these ZnO nanoparticles. The experimental parameters were tuned to achieve optimum conditions for the synthesis of selectively doped ZnO nanomaterials with an experimental duration of 4 hr. These selectively doped ZnO nanoparticles were characterized using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy and scanning electron microscopy (SEM). The solar driven photocatalytic studies have been carried out for organic dyes, i.e., Procion MX-5B dye, Cibacron Brilliant Yellow dye, Indigo Carmine dye, separately and all three mixed, by using gluconic acid modified selectively doped advanced ZnO nanomaterial. The influence of catalyst, its concentration and initial dye concentration resulted in the photocatalytic efficiency of 89% under daylight. Copyright © 2015. Published by Elsevier B.V.

  15. Oxidation of caffeine and related methylxanthines in ascorbate and polyphenol-driven Fenton-type oxidations.

    PubMed

    Stadler, R H; Richoz, J; Turesky, R J; Welti, D H; Fay, L B

    1996-03-01

    Caffeine and related methylxanthines were subjected to free radical mediated oxidation by incubation with Fe(3+)-EDTA/ascorbate and Fe(3+)-EDTA/polyphenolics. The reaction mixtures were analysed by reverse-phase HPLC, revealing the corresponding C-8 hydroxylated analogues as the major products of hydroxyl radical mediated attack. Further oxidation products of caffeine, analysed by liquid chromatography-mass spectrometry (LC-MS), were the N1-, N3- and N7-demethylated methylxanthine analogues theobromine, paraxanthine and theophylline, respectively. Isolable amounts of the imidazole ring operated 6-amino-5-(N-formylmethyl-amino)-1,3-dimethyl-uracil (1,3,7-DAU) derivative were also detected, which was characterised by 1H NMR and mass spectroscopy. The identified products indicate that the pertinent chemical reactions, i.e. C-8 hydroxylation, demethylations, and C8-N9 bond scission, are comparable to the primary metabolic pathways of caffeine in humans. The influence of pH, transition metals, hydrogen peroxide, free radical scavengers and metal chelators on caffeine oxidation was studied. This report illustrates that natural food-borne reactants can aid in identifying specific chemical markers of free radical induced damage. Furthermore, potentially anti-and pro-oxidative reactions can be elucidated which may be important in assessing the impact of nutrient additives and supplements on the shelf life and stability of foods and beverages.

  16. Anodic oxidation with doped diamond electrodes: a new advanced oxidation process.

    PubMed

    Kraft, Alexander; Stadelmann, Manuela; Blaschke, Manfred

    2003-10-31

    Boron-doped diamond anodes allow to directly produce OH* radicals from water electrolysis with very high current efficiencies. This has been explained by the very high overvoltage for oxygen production and many other anodic electrode processes on diamond anodes. Additionally, the boron-doped diamond electrodes exhibit a high mechanical and chemical stability. Anodic oxidation with diamond anodes is a new advanced oxidation process (AOP) with many advantages compared to other known chemical and photochemical AOPs. The present work reports on the use of diamond anodes for the chemical oxygen demand (COD) removal from several industrial wastewaters and from two synthetic wastewaters with malic acid and ethylenediaminetetraacetic (EDTA) acid. Current efficiencies for the COD removal between 85 and 100% have been found. The formation and subsequent removal of by-products of the COD oxidation has been investigated for the first time. Economical considerations of this new AOP are included.

  17. Light-driven biocatalytic oxidation and reduction reactions: scope and limitations.

    PubMed

    Taglieber, Andreas; Schulz, Frank; Hollmann, Frank; Rusek, Monika; Reetz, Manfred T

    2008-03-03

    The quest for practical regeneration concepts for nicotinamide-dependent oxidoreductases continues. Recently we proposed the use of visible light to promote the direct reductive regeneration of a flavin-dependent monooxygenase. With this enzyme (PAMO-P3) light-driven enantioselective Baeyer-Villiger oxidations were performed. In spite of the significant reduction in the complexity achieved, catalytic performance of the novel approach did not meet the requirements for an efficient biocatalytic oxygenation system. Driven by this ultimate goal, we further investigated the limiting factors of our particular system. We discovered that oxidative uncoupling of the flavin-regeneration reaction from enzymatic O2-activation accounts for the futile consumption of approximately 95% of the reducing equivalents provided by the sacrificial electron donor, EDTA. Furthermore, it was found that the apparent turnover frequency (TOF) for PAMO-P3 in the present setup is approximately two orders of magnitude lower than in conventional setups that use NADPH as reductant. This finding was traced to sluggish electron transfer kinetics that arose from an impeded interaction between PAMO-P3-bound FAD and the reducing catalyst. The limiting factors and potential approaches for their circumvention are discussed. Furthermore, we broadened the light-driven regeneration approach to the class of flavin-dependent reductases. By using the Old Yellow Enzyme homologue YqjM as a model system, a significantly higher catalytic turnover for the enzyme catalyst was achieved, which we assign to a higher accessibility of the prosthetic group as well as to the absence of oxidative uncoupling.

  18. Direct Observation of Electrostatically Driven Band Gap Renormalization in a Degenerate Perovskite Transparent Conducting Oxide.

    PubMed

    Lebens-Higgins, Z; Scanlon, D O; Paik, H; Sallis, S; Nie, Y; Uchida, M; Quackenbush, N F; Wahila, M J; Sterbinsky, G E; Arena, Dario A; Woicik, J C; Schlom, D G; Piper, L F J

    2016-01-15

    We have directly measured the band gap renormalization associated with the Moss-Burstein shift in the perovskite transparent conducting oxide (TCO), La-doped BaSnO_{3}, using hard x-ray photoelectron spectroscopy. We determine that the band gap renormalization is almost entirely associated with the evolution of the conduction band. Our experimental results are supported by hybrid density functional theory supercell calculations. We determine that unlike conventional TCOs where interactions with the dopant orbitals are important, the band gap renormalization in La-BaSnO_{3} is driven purely by electrostatic interactions.

  19. Infrared driven CO oxidation reactions on isolated platinum cluster oxides, Pt(n)O(m)+.

    PubMed

    Hermes, Alexander C; Hamilton, Suzanne M; Cooper, Graham A; Kerpal, Christian; Harding, Dan J; Meijer, Gerard; Fielicke, André; Mackenzie, Stuart R

    2012-01-01

    This collaboration has recently shown that infrared excitation can drive decomposition reactions of molecules on the surface of gas-phase transition metal clusters. We describe here a significant extension of this work to the study of bimolecular reactions initiated in a similar manner. Specifically, we have observed the infrared activated CO oxidation reaction (CO(ads) + O(ads) --> CO2(g)) on isolated platinum oxide cations, Pt(n)O(m)+. Small platinum cluster oxides Pt(n)O(m)+ (n = 3-7, m = 2, 4), have been decorated with CO molecules and subjected to multiple photon infrared excitation in the range 400-2200 cm(-1) using the Free Electron Laser for Infrared eXperiments (FELIX). The Pt(n)O(m)CO+ clusters have been characterised by infrared multiple photon dissociation spectroscopy using messenger atom tagging. Evidence is observed for isomers involving both dissociatively and molecularly adsorbed oxygen on the cluster surface. Further information is obtained on the evolution of the cluster structure with number of platinum atoms and CO coverage. In separate experiments, Pt(n)O(m)CO+ clusters have been subjected to infrared heating via the CO stretch around 2100 cm(-1). On all clusters investigated, the CO oxidation reaction, indicated by CO2 loss and production of Pt(n)O(m) = 1+, is found to compete effectively with the CO desorption channel. The experimental observations are compared with the results of preliminary DFT calculations in order to identify both cluster structures and plausible mechanisms for the surface reaction.

  20. The Role of Ultrasound on Advanced Oxidation Processes.

    PubMed

    Babu, Sundaram Ganesh; Ashokkumar, Muthupandian; Neppolian, Bernaurdshaw

    2016-10-01

    This chapter describes the use of ultrasound in remediation of wastewater contaminated with organic pollutants in the absence and presence of other advanced oxidation processes (AOPs) such as sonolysis, sono-ozone process, sonophotocatalysis, sonoFenton systems and sonophoto-Fenton methods in detail. All these methods are explained with the suitable literature illustrations. In most of the cases, hybrid AOPs (combination of ultrasound with one or more AOPs) resulted in superior efficacy to that of individual AOP. The advantageous effects such as additive and synergistic effects obtained by operating the hybrid AOPs are highlighted with appropriate examples. It is worth to mention here that the utilization of ultrasound is not only restricted in preparation of modern active catalysts but also extensively used for the wastewater treatment. Interestingly, ultrasound coupled AOPs are operationally simple, efficient, and environmentally benign, and can be readily applied for large scale industrial processes which make them economically viable.

  1. Iron-Based Metal-Organic Frameworks as Catalysts for Visible Light-Driven Water Oxidation.

    PubMed

    Chi, Le; Xu, Qian; Liang, Xiaoyu; Wang, Jide; Su, Xintai

    2016-03-09

    The development of earth-abundant, active, and stable catalysts is important for solar energy conversion. Metal-organic frameworks (MOFs) have been viewed as a promising class of porous materials, which may have innovative application in photocatalysis. In this paper, three types of Fe-based MOFs and their aminofunctionalized derivatives have been fabricated and systematically studied as water oxidation catalysts (WOCs) for oxygen evolution under visible light irradiation. MIL-101(Fe) possesses a higher current density and earlier onset potential and exhibits excellent visible light-driven oxygen evolution activity than the other Fe-based catalysts. It speeds up the oxygen evolution reaction rate with the higher initial turnover frequencies value of 0.10 s(-1). Our study demonstrates that Fe-based MOFs as efficient WOCs are promising candidates for photocatalytic water oxidation process. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Oxidative stress in aging: advances in proteomic approaches.

    PubMed

    Ortuño-Sahagún, Daniel; Pallàs, Mercè; Rojas-Mayorquín, Argelia E

    2014-01-01

    Aging is a gradual, complex process in which cells, tissues, organs, and the whole organism itself deteriorate in a progressive and irreversible manner that, in the majority of cases, implies pathological conditions that affect the individual's Quality of Life (QOL). Although extensive research efforts in recent years have been made, the anticipation of aging and prophylactic or treatment strategies continue to experience major limitations. In this review, the focus is essentially on the compilation of the advances generated by cellular expression profile analysis through proteomics studies (two-dimensional [2D] electrophoresis and mass spectrometry [MS]), which are currently used as an integral approach to study the aging process. Additionally, the relevance of the oxidative stress factors is discussed. Emphasis is placed on postmitotic tissues, such as neuronal, muscular, and red blood cells, which appear to be those most frequently studied with respect to aging. Additionally, models for the study of aging are discussed in a number of organisms, such as Caenorhabditis elegans, senescence-accelerated probe-8 mice (SAMP8), naked mole-rat (Heterocephalus glaber), and the beagle canine. Proteomic studies in specific tissues and organisms have revealed the extensive involvement of reactive oxygen species (ROS) and oxidative stress in aging.

  3. An advanced oxidation process using ionized gas for wastewater treatment.

    PubMed

    Lee, Eun Ju; Chung, Paul Gene; Kwak, Dong Heui; Kim, Lee Hyung; Kim, Min Jeong

    2010-01-01

    This study on removing non-degradable materials in wastewater focused primarily on advanced oxidation methods such as ozone, ozone/UV and ozone/H2O2. Wastewater treatment using an ionized gas from plasma has been actively progressing. The ionized gas involves reactive species such as O2+, O2- cluster, O radical and OH radical. Since the ionized gas method has such outstanding characteristics as relatively simple structures, non-calorification, non-toxicity and low electricity consumption, it evidently of interest as a new process. A series of experiments were conducted to demonstrate the feasibility of ionized gas as a useful element for the diminution of nondegradable organic matters. On the other hand, a large amount of organic matters were changed to hydrophilic and the compounds containing aromatic functional group gradually decreased. The results implied that the ionized gas has been able to degrade the non-biodegradable organic matters. Therefore, the oxidation process by using an ionized gas process could be considered as an effective alternative unit in water and wastewater treatment plants.

  4. Oxidative Stress in Aging: Advances in Proteomic Approaches

    PubMed Central

    Ortuño-Sahagún, Daniel; Pallàs, Mercè; Rojas-Mayorquín, Argelia E.

    2014-01-01

    Aging is a gradual, complex process in which cells, tissues, organs, and the whole organism itself deteriorate in a progressive and irreversible manner that, in the majority of cases, implies pathological conditions that affect the individual's Quality of Life (QOL). Although extensive research efforts in recent years have been made, the anticipation of aging and prophylactic or treatment strategies continue to experience major limitations. In this review, the focus is essentially on the compilation of the advances generated by cellular expression profile analysis through proteomics studies (two-dimensional [2D] electrophoresis and mass spectrometry [MS]), which are currently used as an integral approach to study the aging process. Additionally, the relevance of the oxidative stress factors is discussed. Emphasis is placed on postmitotic tissues, such as neuronal, muscular, and red blood cells, which appear to be those most frequently studied with respect to aging. Additionally, models for the study of aging are discussed in a number of organisms, such as Caenorhabditis elegans, senescence-accelerated probe-8 mice (SAMP8), naked mole-rat (Heterocephalus glaber), and the beagle canine. Proteomic studies in specific tissues and organisms have revealed the extensive involvement of reactive oxygen species (ROS) and oxidative stress in aging. PMID:24688629

  5. Design Principles for Metal Oxide Redox Materials for Solar-Driven Isothermal Fuel Production

    PubMed Central

    Michalsky, Ronald; Botu, Venkatesh; Hargus, Cory M; Peterson, Andrew A; Steinfeld, Aldo

    2015-01-01

    The performance of metal oxides as redox materials is limited by their oxygen conductivity and thermochemical stability. Predicting these properties from the electronic structure can support the screening of advanced metal oxides and accelerate their development for clean energy applications. Specifically, reducible metal oxide catalysts and potential redox materials for the solar-thermochemical splitting of CO2 and H2O via an isothermal redox cycle are examined. A volcano-type correlation is developed from available experimental data and density functional theory. It is found that the energy of the oxygen-vacancy formation at the most stable surfaces of TiO2, Ti2O3, Cu2O, ZnO, ZrO2, MoO3, Ag2O, CeO2, yttria-stabilized zirconia, and three perovskites scales with the Gibbs free energy of formation of the bulk oxides. Analogously, the experimental oxygen self-diffusion constants correlate with the transition-state energy of oxygen conduction. A simple descriptor is derived for rapid screening of oxygen-diffusion trends across a large set of metal oxide compositions. These general trends are rationalized with the electronic charge localized at the lattice oxygen and can be utilized to predict the surface activity, the free energy of complex bulk metal oxides, and their oxygen conductivity. PMID:26855639

  6. Self-driven visible-blind photodetector based on ferroelectric perovskite oxides

    NASA Astrophysics Data System (ADS)

    Li, Jian-kun; Ge, Chen; Jin, Kui-juan; Du, Jian-yu; Yang, Jing-ting; Lu, Hui-bin; Yang, Guo-zhen

    2017-04-01

    Ultraviolet photodetectors have attracted considerable interest for a variety of applications in health, industry, and science areas. Self-driven visible-blind photodetectors represent an appealing type of sensor, due to the reduced size and high flexibility. In this work, we employed BaTiO3 (BTO) single crystals with a bandgap of 3.2 eV for the realization of a self-driven ultraviolet detector, by utilizing the ferroelectric properties of BTO. We found that the sign of the photocurrent can be reversed by flipping the ferroelectric polarization, which makes the photodetector suitable for electrical manipulation. The photoelectric performance of this photodetector was systematically investigated in terms of rectification character, stability of short-circuit photocurrent, spectral response, and transient photoelectric response. Particularly, the self-driven photodetectors based on BTO showed an ultrafast response time about 200 ps. It is expected that the present work can provide a route for the design of photodetectors based on ferroelectric oxides.

  7. Thermal-driven attachment of gold nanoparticles prepared with ascorbic acid onto indium tin oxide surfaces

    NASA Astrophysics Data System (ADS)

    Aziz, Md. Abdul; Oyama, Munetaka

    2013-05-01

    Thermal-driven attachment of gold nanoparticles (AuNPs), of which size was less than 50 nm, onto the surfaces of indium tin oxide (ITO) is reported as a new phenomenon. This was permitted by preparing AuNPs via the reduction of hydrogen tetrachloroaurate (HAuCl4) with ascorbic acid (AA). While the AuNPs prepared via the AA reduction sparsely attached on the surface of ITO even at room temperature, a heat-up treatment at ca. 75 °C caused denser attachment of AuNPs on ITO surfaces. The attached density and the homogeneity after the thermal treatment were better than those of AuNP/ITO prepared using 3-aminopropyl-trimethoxysilane linker molecules. The denser attachment was observed similarly both by the immersion of ITO samples after the preparations of AuNPs by AA and by the in situ preparation of AuNPs with AA together with ITO samples. Thus, it is considered that the thermal-driven attachment of AuNPs would occur after the formation of AuNPs in the aqueous solutions, not via the growth of AuNPs on ITO surfaces. The preparation of AuNPs with AA would be a key for the thermal-driven attachment because the same attachments were not observed for AuNPs prepared with citrate ions or commercially available tannic acid-capped AuNPs.

  8. Cytosolic and chloroplastic DHARs cooperate in oxidative stress-driven activation of the salicylic acid pathway.

    PubMed

    Rahantaniaina, Marie-Sylviane; Li, Shengchun; Chatel-Innocenti, Gilles; Tuzet, Andrée; Issakidis-Bourguet, Emmanuelle; Mhamdi, Amna; Noctor, Graham

    2017-04-05

    The complexity of plant antioxidative systems gives rise to many unresolved questions. One relates to the functional importance of dehydroascorbate reductases (DHARs) in interactions between ascorbate and glutathione. To investigate this issue, we produced a complete set of loss-of-function mutants for the three annotated Arabidopsis DHARs. The combined loss of DHAR1 and DHAR3 expression decreased extractable activity to very low levels but had little effect on phenotype or ascorbate and glutathione pools in standard conditions. An analysis of the subcellular localization of the DHARs in Arabidopsis lines stably transformed with GFP fusion proteins revealed that DHAR1 and DHAR2 are cytosolic while DHAR3 is chloroplastic, with no evidence for peroxisomal or mitochondrial localizations. When the mutations were introduced into an oxidative stress genetic background (cat2), the dhar1 dhar2 combination decreased glutathione oxidation and inhibited cat2-triggered induction of the salicylic acid pathway. These effects were reversed in cat2 dhar1 dhar2 dhar3 complemented with any of the three DHARs. The data suggest that (1) DHAR can be decreased to negligible levels without marked effects on ascorbate pools; (2) the cytosolic isoforms are particularly important in coupling intracellular H2O2 metabolism to glutathione oxidation; (3) DHAR-dependent glutathione oxidation influences redox-driven salicylic acid accumulation.

  9. A unique isotopic fingerprint during sulfate-driven anaerobic oxidation of methane

    NASA Astrophysics Data System (ADS)

    Antler, G.; Turchyn, A. V.; Herut, B.; Sivan, O.

    2014-12-01

    Bacterial sulfate reduction is responsible for the majority of anaerobic methane oxidation in modern marine sediments. This sulfate-driven AOM can often metabolize all the methane produced within marine sediments, preventing any from reaching the overlying ocean. In certain areas, however, methane concentrations are high enough to form bubbles, which can reach the seafloor, only partially metabolized through sulfate-driven AOM; these areas where methane bubbles into the ocean are called cold seeps, or methane seeps. We use the sulfur and oxygen isotopes of sulfate (d34SSO4 and d18OSO4) in locations where sulfate-driven AOM is occurring both in methane seeps as well as lower flux methane transition zones to show that in methane seeps, the d34SSO4 and d18OSO4 data during the coupled sulfate reduction fall into a very narrow range and with a close to linear relationship (slope 0.37± 0.01 (R^2= 0.98, n=52, 95% confidence interval). In the studied environments, considerably different physical properties exist, excluding the possibility that this linear relationship can be attributed to physical processes such as diffusion, advection or mixing of two end-members. This unique isotopic signature emerges during bacterial sulfate reduction by methane in 'cold' seeps and differs when sulfate is reduced by either organic matter oxidation or by a slower, diffusive flux of methane within marine sediments. We show also that this unique isotope fingerprint is preserved in the rock record in authigenic build-ups of carbonates and barite associated with methane seeps, and may serve as a powerful tool for identifying catastrophic methane release in the geological record.

  10. Advancing data reuse in phyloinformatics using an ontology-driven Semantic Web approach.

    PubMed

    Panahiazar, Maryam; Sheth, Amit P; Ranabahu, Ajith; Vos, Rutger A; Leebens-Mack, Jim

    2013-01-01

    Phylogenetic analyses can resolve historical relationships among genes, organisms or higher taxa. Understanding such relationships can elucidate a wide range of biological phenomena, including, for example, the importance of gene and genome duplications in the evolution of gene function, the role of adaptation as a driver of diversification, or the evolutionary consequences of biogeographic shifts. Phyloinformaticists are developing data standards, databases and communication protocols (e.g. Application Programming Interfaces, APIs) to extend the accessibility of gene trees, species trees, and the metadata necessary to interpret these trees, thus enabling researchers across the life sciences to reuse phylogenetic knowledge. Specifically, Semantic Web technologies are being developed to make phylogenetic knowledge interpretable by web agents, thereby enabling intelligently automated, high-throughput reuse of results generated by phylogenetic research. This manuscript describes an ontology-driven, semantic problem-solving environment for phylogenetic analyses and introduces artefacts that can promote phyloinformatic efforts to promote accessibility of trees and underlying metadata. PhylOnt is an extensible ontology with concepts describing tree types and tree building methodologies including estimation methods, models and programs. In addition we present the PhylAnt platform for annotating scientific articles and NeXML files with PhylOnt concepts. The novelty of this work is the annotation of NeXML files and phylogenetic related documents with PhylOnt Ontology. This approach advances data reuse in phyloinformatics.

  11. Advancing data reuse in phyloinformatics using an ontology-driven Semantic Web approach

    PubMed Central

    2013-01-01

    Phylogenetic analyses can resolve historical relationships among genes, organisms or higher taxa. Understanding such relationships can elucidate a wide range of biological phenomena, including, for example, the importance of gene and genome duplications in the evolution of gene function, the role of adaptation as a driver of diversification, or the evolutionary consequences of biogeographic shifts. Phyloinformaticists are developing data standards, databases and communication protocols (e.g. Application Programming Interfaces, APIs) to extend the accessibility of gene trees, species trees, and the metadata necessary to interpret these trees, thus enabling researchers across the life sciences to reuse phylogenetic knowledge. Specifically, Semantic Web technologies are being developed to make phylogenetic knowledge interpretable by web agents, thereby enabling intelligently automated, high-throughput reuse of results generated by phylogenetic research. This manuscript describes an ontology-driven, semantic problem-solving environment for phylogenetic analyses and introduces artefacts that can promote phyloinformatic efforts to promote accessibility of trees and underlying metadata. PhylOnt is an extensible ontology with concepts describing tree types and tree building methodologies including estimation methods, models and programs. In addition we present the PhylAnt platform for annotating scientific articles and NeXML files with PhylOnt concepts. The novelty of this work is the annotation of NeXML files and phylogenetic related documents with PhylOnt Ontology. This approach advances data reuse in phyloinformatics. PMID:24565381

  12. Overview of the C-2U Advanced Beam-Driven FRC Experimental Program

    NASA Astrophysics Data System (ADS)

    Gota, H.; Binderbauer, M. W.; Tajima, T.; Putvinski, S.; Tuszewski, M.; Barnes, D.; Dettrick, S.; Garate, E.; Korepanov, S.; Smirnov, A.; Thompson, M. C.; Yang, X.; Ivanov, A. A.; the TAE Team

    2015-11-01

    The world's largest compact toroid (CT) device, C-2, has recently been upgraded to C-2U at Tri Alpha Energy to seek for a sustainment of field-reversed configuration (FRC) plasma by neutral-beam (NB) injection. The C-2 experimental program was successfully completed with dramatic improvements in confinement and stability of FRC plasmas, as well as demonstrated plasma pressure increase and plasma heating by NB injection. To enhance the NB injection effect and further improve the FRC performance, the C-2U experimental program has started with following key system upgrades: (i) increased total NB input power to 10 + MW (15 keV hydrogen) with tilted injection angle; (ii) enhanced edge-biasing capability for stability control; (iii) upgraded particle inventory control systems. The initial C-2U experiment has already demonstrated much further improvements, revealing advanced beam-driven FRC plasmas. In the best operating regime we have successfully achieved plasma sustainment up to 5 + ms; while, in the longer-pulsed regime the plasma lifetime can be extended up to the end of NB pulse-duration (8 + ms). The overall C-2U experimental program and the initial experimental results will be presented at the meeting.

  13. Treatment of real industrial wastewater using the combined approach of advanced oxidation followed by aerobic oxidation.

    PubMed

    Ramteke, Lokeshkumar P; Gogate, Parag R

    2016-05-01

    Fenton oxidation and ultrasound-based pretreatment have been applied to improve the treatment of real industrial wastewater based on the use of biological oxidation. The effect of operating parameters such as Fe(2+) loading, contact time, initial pH, and hydrogen peroxide loading on the extent of chemical oxygen demand (COD) reduction and change in biochemical oxygen demand (BOD5)/COD ratio has been investigated. The optimum operating conditions established for the pretreatment were initial pH of 3.0, Fe(2+) loading of 2.0, and 2.5 g L(-1) for the US/Fenton/stirring and Fenton approach, respectively, and temperature of 25 °C with initial H2O2 loading of 1.5 g L(-1). The use of pretreatment resulted in a significant increase in the BOD5/COD ratio confirming the production of easily digestible intermediates. The effect of the type of sludge in the aerobic biodegradation was also investigated based on the use of primary activated sludge (PAS), modified activated sludge (MAS), and activated sludge (AS). Enhanced removal of the pollutants as well as higher biomass yield was observed for MAS as compared to PAS and AS. The use of US/Fenton/stirring pretreatment under the optimized conditions followed by biological oxidation using MAS resulted in maximum COD removal at 97.9 %. The required hydraulic retention time for the combined oxidation system was also significantly lower as compared to only biological oxidation operation. Kinetic studies revealed that the reduction in the COD followed a first-order kinetic model for advanced oxidation and pseudo first-order model for biodegradation. The study clearly established the utility of the combined technology for the effective treatment of real industrial wastewater.

  14. Iron(3) oxide-based nanoparticles as catalysts in advanced organic aqueous oxidation.

    PubMed

    Zelmanov, Grigory; Semiat, Raphael

    2008-01-01

    Water contaminated with dissolved organic matter is an important issue to resolve for all-purpose uses. The catalytic behavior of iron-based nanocatalysts was investigated for the treatment of contaminated water in the advanced chemical oxidation process. In this study, typical organic contaminants, such as ethylene glycol and phenol, were chosen to simulate common contaminants. It was shown that the two substances are efficiently destroyed by the Fenton-like reaction using iron(3) oxide-based nanocatalysts in the presence of hydrogen peroxide without the need for UV or visible radiation sources at room temperature. A strong effect of nanocatalyst concentration on reaction rate was shown. The kinetic reaction was found and the reaction rate coefficient k was calculated.

  15. Oxidative Stress to the Cornea, Changes in Corneal Optical Properties, and Advances in Treatment of Corneal Oxidative Injuries

    PubMed Central

    Cejka, Cestmir; Cejkova, Jitka

    2015-01-01

    Oxidative stress is involved in many ocular diseases and injuries. The imbalance between oxidants and antioxidants in favour of oxidants (oxidative stress) leads to the damage and may be highly involved in ocular aging processes. The anterior eye segment and mainly the cornea are directly exposed to noxae of external environment, such as air pollution, radiation, cigarette smoke, vapors or gases from household cleaning products, chemical burns from splashes of industrial chemicals, and danger from potential oxidative damage evoked by them. Oxidative stress may initiate or develop ocular injury resulting in decreased visual acuity or even vision loss. The role of oxidative stress in the pathogenesis of ocular diseases with particular attention to oxidative stress in the cornea and changes in corneal optical properties are discussed. Advances in the treatment of corneal oxidative injuries or diseases are shown. PMID:25861412

  16. Tin doping speeds up hole transfer during light-driven water oxidation at hematite photoanodes.

    PubMed

    Dunn, Halina K; Feckl, Johann M; Müller, Alexander; Fattakhova-Rohlfing, Dina; Morehead, Samuel G; Roos, Julian; Peter, Laurence M; Scheu, Christina; Bein, Thomas

    2014-11-28

    Numerous studies have shown that the performance of hematite photoanodes for light-driven water splitting is improved substantially by doping with various metals, including tin. Although the enhanced performance has commonly been attributed to bulk effects such as increased conductivity, recent studies have noted an impact of doping on the efficiency of the interfacial transfer of holes involved in the oxygen evolution reaction. However, the methods used were not able to elucidate the origin of this improved efficiency, which could originate from passivation of surface electron-hole recombination or catalysis of the oxygen evolution reaction. The present study used intensity-modulated photocurrent spectroscopy (IMPS), which is a powerful small amplitude perturbation technique that can de-convolute the rate constants for charge transfer and recombination at illuminated semiconductor electrodes. The method was applied to examine the kinetics of water oxidation on thin solution-processed hematite model photoanodes, which can be Sn-doped without morphological change. We observed a significant increase in photocurrent upon Sn-doping, which is attributed to a higher transfer efficiency. The kinetic data obtained using IMPS show that Sn-doping brings about a more than tenfold increase in the rate constant for water oxidation by photogenerated holes. This result provides the first demonstration that Sn-doping speeds up water oxidation on hematite by increasing the rate constant for hole transfer.

  17. Mechanistic study of the visible-light-driven photocatalytic inactivation of bacteria by graphene oxide-zinc oxide composite

    NASA Astrophysics Data System (ADS)

    Wu, Dan; An, Taicheng; Li, Guiying; Wang, Wei; Cai, Yuncheng; Yip, Ho Yin; Zhao, Huijun; Wong, Po Keung

    2015-12-01

    The visible-light-driven (VLD) photocatalytic activity of graphene oxide-zinc oxide (GO-ZnO) composite prepared by a simple hydrothermal method was evaluated toward the inactivation of Escherichia coli K-12. The results showed that GO-ZnO composite had excellent VLD photocatalytic bacterial inactivation activity, comparing with those of ZnO and GO, which was attributed to the strong interaction between ZnO and GO in the composite. Accordingly, an interaction induced VLD photocatalytic inactivation mechanism of the strong interaction of GO with ZnO within the GO-ZnO composite was proposed. GO served as a photosensitizer and facilitated the charge separation and transfer, thus boosted the massive production of reactive oxygen species such as rad OHbulk, which was identified as the major reactive species from conduction band of ZnO, and resulted in a remarkable enhancement of bacterial inactivation efficiency. Moreover, GO-ZnO composite showed obviously superior photocatalytic bacterial inactivation within 10 min under natural solar light irradiation, indicating that GO-ZnO composite has great potential in wastewater treatment and environmental protection.

  18. Stable Solar-Driven Water Oxidation to O2(g) by Ni-Oxide-Coated Silicon Photoanodes.

    PubMed

    Sun, Ke; McDowell, Matthew T; Nielander, Adam C; Hu, Shu; Shaner, Matthew R; Yang, Fan; Brunschwig, Bruce S; Lewis, Nathan S

    2015-02-19

    Semiconductors with small band gaps (<2 eV) must be stabilized against corrosion or passivation in aqueous electrolytes before such materials can be used as photoelectrodes to directly produce fuels from sunlight. In addition, incorporation of electrocatalysts on the surface of photoelectrodes is required for efficient oxidation of H2O to O2(g) and reduction of H2O or H2O and CO2 to fuels. We report herein the stabilization of np(+)-Si(100) and n-Si(111) photoanodes for over 1200 h of continuous light-driven evolution of O2(g) in 1.0 M KOH(aq) by an earth-abundant, optically transparent, electrocatalytic, stable, conducting nickel oxide layer. Under simulated solar illumination and with optimized index-matching for proper antireflection, NiOx-coated np(+)-Si(100) photoanodes produced photocurrent-onset potentials of -180 ± 20 mV referenced to the equilibrium potential for evolution of O2(g), photocurrent densities of 29 ± 1.8 mA cm(-2) at the equilibrium potential for evolution of O2(g), and a solar-to-O2(g) conversion figure-of-merit of 2.1%.

  19. Advanced oxidation-based treatment of furniture industry wastewater.

    PubMed

    Tichonovas, Martynas; Krugly, Edvinas; Grybauskas, Arturas; Jankūnaitė, Dalia; Račys, Viktoras; Martuzevičius, Dainius

    2017-07-16

    The paper presents a study on the treatment of the furniture industry wastewater in a bench scale advanced oxidation reactor. The researched technology utilized a simultaneous application of ozone, ultraviolet radiation and surface-immobilized TiO2 nanoparticle catalyst. Various combinations of processes were tested, including photolysis, photocatalysis, ozonation, catalytic ozonation, photolytic ozonation and photocatalytic ozonation were tested against the efficiency of degradation. The efficiency of the processes was primarily characterized by the total organic carbon (TOC) analysis, indicating the remaining organic material in the wastewater after the treatment, while the toxicity changes in wastewater were researched by Daphnia magna toxicity tests. Photocatalytic ozonation was confirmed as the most effective combination of processes (99.3% of TOC reduction during 180 min of treatment), also being the most energy efficient (4.49-7.83 MJ/g). Photocatalytic ozonation and photolytic ozonation remained efficient across a wide range of pH (3-9), but the pH was an important factor in photocatalysis. The toxicity of wastewater depended on the duration of the treatment: half treated water was highly toxic, while fully treated water did not possess any toxicity. Our results indicate that photocatalytic ozonation has a high potential for the upscaling and application in industrial settings.

  20. OH radical monitoring technologies for AOP advanced oxidation process.

    PubMed

    Han, S K; Nam, S N; Kang, J W

    2002-01-01

    This study has been conducted to investigate OH radical monitoring technologies for the advanced oxidation process (AOP). OH radicals can be measured directly or indirectly through electron paramagnetic resonance (EPR), hydrogen peroxide method and probe compounds such as pCBA. Among the various AOPs, we focused on the application of EPR technique for *OH monitoring in the ultrasonic irradiation process. EPR method is a valuable tool and has a high sensitivity for radical measuring. Our study was performed with 20 kHz ultrasonic processor in 20 ml DMPO (1 mM) solution. The amount of DMPO-OH adduct with hyperfine constants aN = aH = 1.49 mT and g-value 2.0054, coincided with those of the DMPO-OH adduct depends on the reaction time of the sonication. Also, we have found that at least, *OH was accumulated by 2 x 10(-10) M for 10 min sonication, when 60% of the initial amount was destroyed through *OH monitoring using a probe compound. With these results, we could assume that recombination of *OH to form hydrogen peroxide occurs at the interfacial region.

  1. Degradation of 1,4-dioxane using advanced oxidation processes.

    PubMed

    Chitra, Sengadir; Paramasivan, Kanapathy; Cheralathan, Mayilsamy; Sinha, Pradeep Kumar

    2012-03-01

    In the nuclear industry 1,4-dioxane is used as a solvent in liquid scintillation technique for measuring low-energy beta-emitters such as ³H or C¹⁴ in aqueous media. Improper disposal of 1,4-dioxane can contaminate the ground and surface waters. Conventional wastewater treatment processes like chemical treatment, air stripping, carbon adsorption, and biological treatment are ineffective for the degradation of 1,4-dioxane. In the present study, the kinetics of degradation of 1,4-dioxane using advanced oxidation processes viz., H₂O₂ alone, Fe(II) + H₂O₂, UV (15 W) + H₂O₂, UV (15 W) + Fe(II) + H₂O₂, US (130 KHz) + Fe(II) + H₂O₂, and sunlight + Fe(II) + H₂O₂ at pH 3.0 was investigated. The optimization of Fe (II) for the processes using Fe (II) + H₂O₂ was carried out. The kinetics of degradation using sunlight + Fe (II) + H₂O₂ was found to be fastest when compared to the other processes. The degradation was found to follow first-order kinetics. Formation of acidic intermediates was suspected from the observed pH changes during the degradation processes.

  2. Mixed-oxide fuels testing in the advanced test reactor

    SciTech Connect

    Sterbentz, J.W.; Ryskamp, J.M.; Mason, S.C.; Chang, G.S.

    1994-12-31

    A report recently issued by the National Academy of Sciences describes the need to dispose of 50 metric tons of U.S. weapons-grade plutonium and a similar amount from Russia and makes recommendations for means of disposal. One principal recommendation is to use the plutonium as once-through fuel in existing commercial U.S. light water reactors (LWRs). The report states that a coordinated program of research and development should be undertaken immediately to clarify and resolve the identified technical uncertainties. This paper presents a solution to one needed program: reactor testing of mixed-oxide (MOX) fuels. Currently, weapons-grade plutonium MOX and other types of advanced plutonium-based fuels are being considered as a disposition fuel form. The proposed weapons-grade MOX fuel is unusual, even relative to ongoing foreign experience with reactor-grade MOX power reactor fuel. Some demonstration of the in-reactor thermal, mechanical, and fission gas release behavior of a prototype fuel will most likely be required in a limited number of test reactor irradiations.

  3. Industrial wastewater treatment by an advanced oxidation process.

    PubMed

    Gunukula, R V; Tittlebaum, M E

    2001-01-01

    The overall objective of this study was to evaluate an advanced oxidation process (AOP) used to treat oil and grease (O&G), total petroleum hydrocarbons (TPH), and chemical oxygen demand (COD) of industrial wastewaters generated during barge cleaning operations. This wastewater generally contains appreciable concentrations of O&G, TPH, COD, biochemical oxygen demand (BOD) and benzene, toluene, ethylbenzene and xylene (BTEX) compounds. A bench scale AOP test unit was designed and built for the treatment of the barge cleaning industrial wastewater. The AOP test unit was a 0.33 gpm mobile, modular unit consisting of two contact chambers, two counter current columns and two catalytic chambers. Six experiments were performed using the AOP unit to determine its effectiveness on the reduction of O&G, TPH, and COD. The wastewater was delivered to the AOP from a storage tank. The unit was run for a total of 120 minutes at various gas delivery rates of ozone for each treatment run. Influent and effluent samples were collected at 30 minutes intervals and analyzed for O&G, TPH, and COD. Significant reductions in O&G and TPH concentrations were observed. Oxygen alone indicated a 50% removal efficiency for O&G and TPH. The ozone treatment efficiency was 86% for O&G and TPH at a dosage rate of 12 SCFH and 82% for a dosage rate of 6 SCFH.

  4. Climate change-driven treeline advances in the Urals alter soil microbial communities

    NASA Astrophysics Data System (ADS)

    Djukic, Ika; Moiseev, Pavel; Hagedorn, Frank

    2016-04-01

    Climatic warming may affect microbial communities and their functions either directly through increased temperatures or indirectly by changes in vegetation. Treelines are temperature-limited vegetation boundaries from tundra to forests. In unmanaged regions of the Ural mountains, there is evidence that the forest-tundra ecotone has shifted upward in response to climate warming during the 20th century. Little is known about the effects of the treeline advances on the microbial structure and function and hence they feedbacks on the belowground carbon and nitrogen cycling In our study, we aimed to estimate how ongoing upward shifts of the treeline ecotone might affect soil biodiversity and its function and hence soil carbon (C) and nitrogen (N) dynamics in the Southern and Polar Ural mountains. Along altitudinal gradients reaching from the tundra to forests, we determined the soil microbial community composition (using Phospholipid Fatty Acids method) and quantified the activity of several extracellular enzymes involved in the C and nutrient cycling. In addition, we measured C pools in biomass and soils and quantified C and N mineralization. The results for the top soils, both in South Urals and in the Polar Ural, indicate a close link between climate change driven vegetation changes and soil microbial communities. The observed changes in microbial structure are induced through the resulting more favorable conditions than due to a shift in litter quality. The activities of chitinase were significantly higher under trees than under herbaceous plants, while activities of cellulase and protease declined with altitude from the tundra to the closed forest. In contrast to enzymatic activities, soil carbon stocks did not change significantly with altitude very likely as a result of a balancing out of increased C inputs from vegetation by an enhanced C output through mineralization with forest expansion. The accelerated organic matter turnover in the forest than in the tundra

  5. Current-driven phase-change optical gate switch using indium-tin-oxide heater

    NASA Astrophysics Data System (ADS)

    Kato, Kentaro; Kuwahara, Masashi; Kawashima, Hitoshi; Tsuruoka, Tohru; Tsuda, Hiroyuki

    2017-07-01

    We proposed and fabricated a current-driven phase-change optical gate switch using a Ge2Sb2Te5 (GST225) thin film, an indium-tin-oxide (ITO) heater, and a Si waveguide. Microfabrication technology compatible with CMOS fabrication was used for the fabrication of the Si waveguide. The repetitive phase changing of GST225 was obtained by injecting a current pulse into the ITO heater beneath the GST225 thin film. The switching operation was observed by injecting a 100-ns current pulse of 20 mA into the ITO heater. The average extinction ratio over the wavelength range of 1,525 to 1,625 nm was 1.2 dB.

  6. Electroluminescence from localized defects in zinc oxide: toward electrically driven single photon sources at room temperature.

    PubMed

    Choi, Sumin; Berhane, Amanuel M; Gentle, Angus; Ton-That, Cuong; Phillips, Matthew R; Aharonovich, Igor

    2015-03-18

    Single photon sources are required for a wide range of applications in quantum information science, quantum cryptography, and quantum communications. However, the majority of room temperature emitters to date are only excited optically, which limits their proper integration into scalable devices. In this work, we overcome this limitation and present room temperature electrically driven light emission from localized defects in zinc oxide (ZnO) nanoparticles and thin films. The devices emit in the red spectral range and show excellent rectifying behavior. The emission is stable over an extensive period of time, providing an important prerequisite for practical devices. Our results open possibilities for building new ZnO-based quantum integrated devices that incorporate solid-state single photon sources for quantum information technologies.

  7. Alkaline electrochemical advanced oxidation process for chromium oxidation at graphitized multi-walled carbon nanotubes.

    PubMed

    Xue, Yudong; Zheng, Shili; Sun, Zhi; Zhang, Yi; Jin, Wei

    2017-09-01

    Alkaline electrochemical advanced oxidation processes for chromium oxidation and Cr-contaminated waste disposal were reported in this study. The highly graphitized multi-walled carbon nanotubes g-MWCNTs modified electrode was prepared for the in-situ electrochemical generation of HO2(-). RRDE test results illustrated that g-MWCNTs exhibited much higher two-electron oxygen reduction activity than other nanocarbon materials with peak current density of 1.24 mA cm(-2), %HO2(-) of 77.0% and onset potential of -0.15 V (vs. Hg/HgO). It was originated from the highly graphitized structure and good electrical conductivity as illustrated from the Raman, XRD and EIS characterizations, respectively. Large amount of reactive oxygen species (HO2(-) and ·OH) were in-situ electro-generated from the two-electron oxygen reduction and chromium-induced alkaline electro-Fenton-like reaction. The oxidation of Cr(III) was efficiently achieved within 90 min and the conversion ratio maintained more than 95% of the original value after stability test, offering an efficient and green approach for the utilization of Cr-containing wastes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. First-principles data-driven discovery of transition metal oxides for artificial photosynthesis

    NASA Astrophysics Data System (ADS)

    Yan, Qimin

    We develop a first-principles data-driven approach for rapid identification of transition metal oxide (TMO) light absorbers and photocatalysts for artificial photosynthesis using the Materials Project. Initially focusing on Cr, V, and Mn-based ternary TMOs in the database, we design a broadly-applicable multiple-layer screening workflow automating density functional theory (DFT) and hybrid functional calculations of bulk and surface electronic and magnetic structures. We further assess the electrochemical stability of TMOs in aqueous environments from computed Pourbaix diagrams. Several promising earth-abundant low band-gap TMO compounds with desirable band edge energies and electrochemical stability are identified by our computational efforts and then synergistically evaluated using high-throughput synthesis and photoelectrochemical screening techniques by our experimental collaborators at Caltech. Our joint theory-experiment effort has successfully identified new earth-abundant copper and manganese vanadate complex oxides that meet highly demanding requirements for photoanodes, substantially expanding the known space of such materials. By integrating theory and experiment, we validate our approach and develop important new insights into structure-property relationships for TMOs for oxygen evolution photocatalysts, paving the way for use of first-principles data-driven techniques in future applications. This work is supported by the Materials Project Predictive Modeling Center and the Joint Center for Artificial Photosynthesis through the U.S. Department of Energy, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, under Contract No. DE-AC02-05CH11231. Computational resources also provided by the Department of Energy through the National Energy Supercomputing Center.

  9. Peroxynitrite-driven mechanisms in diabetes and insulin resistance - the latest advances.

    PubMed

    Stadler, K

    2011-01-01

    Since its discovery, peroxynitrite has been known as a potent oxidant in biological systems, and a rapidly growing body of literature has characterized its biochemistry and role in the pathophysiology of various conditions. Either directly or by inducing free radical pathways, peroxynitrite damages vital biomolecules such as DNA, proteins including enzymes with important functions, and lipids. It also initiates diverse reactions leading eventually to disrupted cell signaling, cell death, and apoptosis. The potential role and contribution of this deleterious species has been the subject of investigation in several important diseases, including but not limited to, cancer, neurodegeneration, stroke, inflammatory conditions, cardiovascular problems, and diabetes mellitus. Diabetes, obesity, insulin resistance, and diabetes-related complications represent a major health problem at epidemic levels. Therefore, tremendous efforts have been put into investigation of the molecular basics of peroxynitrite-related mechanisms in diabetes. Studies constantly seek new therapeutical approaches in order to eliminate or decrease the level of peroxynitrite, or to interfere with its downstream mechanisms. This review is intended to emphasize the latest findings about peroxynitrite and diabetes, and, in addition, to discuss recent and novel advances that are likely to contribute to a better understanding of peroxynitrite-mediated damage in this disease.

  10. Facile synthesis of a ruthenium assembly and its application for light-driven oxidation of alcohols in water.

    PubMed

    Chao, Duobin; Fu, Wen-Fu

    2013-05-10

    A supramolecular assembly containing two light harvesting fragments [Ru(tpy)2](2+) and one catalytic unit [Ru(tpy)(bpy)Cl](+) was synthesized in a facile manner in 90% yield, and exhibited high photocatalytic product-selectivity compared with the corresponding bimolecular system in the light-driven oxidation of alcohols using [Co(NH3)5Cl]Cl2 as a sacrificial oxidant in water at room temperature.

  11. Superoxide Dismutase 1 Protects Hepatocytes from Type I Interferon-Driven Oxidative Damage

    PubMed Central

    Bhattacharya, Anannya; Hegazy, Ahmed N.; Deigendesch, Nikolaus; Kosack, Lindsay; Cupovic, Jovana; Kandasamy, Richard K.; Hildebrandt, Andrea; Merkler, Doron; Kühl, Anja A.; Vilagos, Bojan; Schliehe, Christopher; Panse, Isabel; Khamina, Kseniya; Baazim, Hatoon; Arnold, Isabelle; Flatz, Lukas; Xu, Haifeng C.; Lang, Philipp A.; Aderem, Alan; Takaoka, Akinori; Superti-Furga, Giulio; Colinge, Jacques; Ludewig, Burkhard; Löhning, Max; Bergthaler, Andreas

    2015-01-01

    Summary Tissue damage caused by viral hepatitis is a major cause of morbidity and mortality worldwide. Using a mouse model of viral hepatitis, we identified virus-induced early transcriptional changes in the redox pathways in the liver, including downregulation of superoxide dismutase 1 (Sod1). Sod1−/− mice exhibited increased inflammation and aggravated liver damage upon viral infection, which was independent of T and NK cells and could be ameliorated by antioxidant treatment. Type I interferon (IFN-I) led to a downregulation of Sod1 and caused oxidative liver damage in Sod1−/− and wild-type mice. Genetic and pharmacological ablation of the IFN-I signaling pathway protected against virus-induced liver damage. These results delineate IFN-I mediated oxidative stress as a key mediator of virus-induced liver damage and describe a mechanism of innate-immunity-driven pathology, linking IFN-I signaling with antioxidant host defense and infection-associated tissue damage. Video Abstract PMID:26588782

  12. Chemically derived luminescent graphene oxide nanosheets and its sunlight driven photocatalytic activity against methylene blue dye

    NASA Astrophysics Data System (ADS)

    Kumar, Sumeet; Kumar, Ashok

    2016-12-01

    In the present work, graphene oxide (GO) nanosheets (NSs) have been synthesized with precise control over their thickness and molecular structure. The existence of oxygen containing functional groups on GO NSs through chemical treatment confers remarkable optical properties on GO. XRD, TEM, Raman and FTIR techniques were used to confirm the phase and degree of oxidation, morphology, structural information and chemical structure of the synthesized GO NSs. UV-Vis. spectroscopy was employed to study the optical absorption properties of the synthesized GO NSs. The excitation wavelength dependent PL measurements of the synthesized GO NSs were carried out which could be useful for the design and development of GO based next generation optoelectronic devices. The most fascinating luminescent property of synthesized GO NSs is that its luminescence peak position can be easily tuned by only varying the excitation wavelength without significant changes in its size and chemical composition. In order to study the photocatalytic degradation of methylene blue (MB) dye using GO NSs as a photocatalyst, a sunlight driven photocatalytic activity has been performed. The degradation rate of MB dye becomes fast when GO NSs are added to the dye solution. The photodegradation efficiency of GO NSs is calculated to be 60%. The present results indicate that synthesized GO NSs can be used as sunlight active photocatalyst. The optimistic response to sunlight irradiation validates the potential of GO NSs in solar energy conversion.

  13. Electron-Driven Metal Oxide Effusion and Graphene Gasification at Room Temperature.

    PubMed

    Ta, Huy Q; Bachmatiuk, Alicja; Warner, Jamie H; Zhao, Liang; Sun, Yinghui; Zhao, Jiong; Gemming, Thomas; Trzebicka, Barbara; Liu, Zhongfan; Pribat, Didier; Rümmeli, Mark H

    2016-06-28

    Metal oxide nanoparticles decorating graphene have attracted abundant interest in the scientific community owing to their significant application in various areas such as batteries, gas sensors, and photocatalysis. In addition, metal and metal oxide nanoparticles are of great interest for the etching of graphene, for example, to form nanoribbons, through gasification reactions. Hence it is important to have a good understanding of how nanoparticles interact with graphene. In this work we examine, in situ, the behavior of CuO and ZnO nanoparticles on graphene at room temperature while irradiated by electrons in a transmission electron microscope. ZnO is shown to etch graphene through gasification. In the gasification reaction C from graphene is released as CO or CO2. We show that the reaction can occur at room temperature. Moreover, CuO and ZnO particles trapped within a graphene fold are shown to effuse out of a fold through small ruptures. The mass transport in the effusion process between the CuO and ZnO particles is fundamentally different. Mass transport for CuO occurs in an amorphous phase, while for ZnO mass transport occurs through the short-lived gliding of vacancies and dislocations. The work highlights the potential and wealth of electron beam driven chemical reactions of nanomaterials, even at room temperature.

  14. Advanced oxidation protein products and ischaemia-modified albumin in obstructive sleep apnea.

    PubMed

    Ozben, Serkan; Huseyinoglu, Nergiz; Hanikoglu, Ferhat; Guvenc, Tolga Sinan; Yildirim, Binnaz Zeynep; Cort, Aysegul; Ozdem, Sebahat; Ozben, Tomris

    2014-11-01

    Several studies have shown that obstructive sleep apnea increases incidence of cardiovascular morbidity and mortality. The high systemic oxidative stress in obstructive sleep apnea has been considered as a major pathogenic mechanism leading to cardiovascular disease. Oxidative stress-related lipid and DNA oxidation in obstructive sleep apnea have been reported in the previous studies. In contrast, there is limited and contradictory information regarding protein oxidation in obstructive sleep apnea patients such as ischaemia-modified albumin and advanced oxidation protein products. Therefore, we aimed to investigate plasma ischaemia-modified albumin and advanced oxidation protein products and their correlation with total oxidative status and total antioxidative capacity in the obstructive sleep apnea patients. Plasma ischaemia-modified albumin, advanced oxidation protein products, total oxidative status and total antioxidative capacity were measured in 25 healthy volunteers and 59 obstructive sleep apnea patients diagnosed with polysomnography. Plasma total antioxidative capacity was significantly lower (P = 0·012) and total oxidative status was significantly higher (P < 0·001) in the patients compared to the controls demonstrating increased oxidative stress in the patients. Plasma advanced oxidation protein products were significantly higher in the patients than the controls (P = 0·024). Plasma ischaemia-modified albumin levels were not statistically different between the obstructive sleep apnea patients and controls (P = 0·74). We conclude that high systemic oxidative stress in obstructive sleep apnea is reflected by increased advanced oxidation protein products without causing an increase in ischaemia-modified albumin. © 2014 Stichting European Society for Clinical Investigation Journal Foundation.

  15. Mixed oxide fuel testing capabilities in the Advanced Test Reactor

    SciTech Connect

    Ryskamp, J.M.; Sterbentz, J.W.; Chang, G.S.; Terry, W.K.

    1996-08-01

    The most attractive way to dispose of weapons-grade Plutonium (WGPu) is to use WGPu as fuel in existing light water reactors (LWRs) in the form of mixed oxide (MOX) fuel--i.e., plutonia (PuO{sub 2}) mixed with urania (UO{sub 2}). Before US reactors could be used for this purpose, their operating licenses would have to be amended. Numerous technical issues must be resolved before LWR operating licenses can be amended to allow the use of MOX fuel. The Advanced Test Reactor (ATR) at the Idaho National Engineering Laboratory (INEL) possesses many advantages for performing tests to resolve most of the issues. It has ample core test volume, high neutron flux, test loops with cooling systems independent of the core coolant, and extensive support facilities. The ATR can deliver a neutron flux of appropriate intensity and energy distribution to the MOX test specimens while simultaneously accommodating test requirements for other programs. The authors have performed calculations to show that the use of hafnium shrouds can produce spectrum adjustments that will bring the flux spectrum in ATR test loops into a good approximation to the spectrum anticipated in a commercial LWR containing MOX fuel while allowing operation of the test fuel assemblies near their design values of linear heat generation rate. The ATR would be a nearly ideal test bed for developing data needed to support applications to license LWRs for operation with MOX fuel made from weapons-grade plutonium. Furthermore, this data can be obtained more quickly by using ATR instead of testing in a commercial LWR.

  16. Modular advanced oxidation process enabled by cathodic hydrogen peroxide production.

    PubMed

    Barazesh, James M; Hennebel, Tom; Jasper, Justin T; Sedlak, David L

    2015-06-16

    Hydrogen peroxide (H2O2) is frequently used in combination with ultraviolet (UV) light to treat trace organic contaminants in advanced oxidation processes (AOPs). In small-scale applications, such as wellhead and point-of-entry water treatment systems, the need to maintain a stock solution of concentrated H2O2 increases the operational cost and complicates the operation of AOPs. To avoid the need for replenishing a stock solution of H2O2, a gas diffusion electrode was used to generate low concentrations of H2O2 directly in the water prior to its exposure to UV light. Following the AOP, the solution was passed through an anodic chamber to lower the solution pH and remove the residual H2O2. The effectiveness of the technology was evaluated using a suite of trace contaminants that spanned a range of reactivity with UV light and hydroxyl radical (HO(•)) in three different types of source waters (i.e., simulated groundwater, simulated surface water, and municipal wastewater effluent) as well as a sodium chloride solution. Irrespective of the source water, the system produced enough H2O2 to treat up to 120 L water d(-1). The extent of transformation of trace organic contaminants was affected by the current density and the concentrations of HO(•) scavengers in the source water. The electrical energy per order (EEO) ranged from 1 to 3 kWh m(-3), with the UV lamp accounting for most of the energy consumption. The gas diffusion electrode exhibited high efficiency for H2O2 production over extended periods and did not show a diminution in performance in any of the matrices.

  17. Modular Advanced Oxidation Process Enabled by Cathodic Hydrogen Peroxide Production

    PubMed Central

    2015-01-01

    Hydrogen peroxide (H2O2) is frequently used in combination with ultraviolet (UV) light to treat trace organic contaminants in advanced oxidation processes (AOPs). In small-scale applications, such as wellhead and point-of-entry water treatment systems, the need to maintain a stock solution of concentrated H2O2 increases the operational cost and complicates the operation of AOPs. To avoid the need for replenishing a stock solution of H2O2, a gas diffusion electrode was used to generate low concentrations of H2O2 directly in the water prior to its exposure to UV light. Following the AOP, the solution was passed through an anodic chamber to lower the solution pH and remove the residual H2O2. The effectiveness of the technology was evaluated using a suite of trace contaminants that spanned a range of reactivity with UV light and hydroxyl radical (HO•) in three different types of source waters (i.e., simulated groundwater, simulated surface water, and municipal wastewater effluent) as well as a sodium chloride solution. Irrespective of the source water, the system produced enough H2O2 to treat up to 120 L water d–1. The extent of transformation of trace organic contaminants was affected by the current density and the concentrations of HO• scavengers in the source water. The electrical energy per order (EEO) ranged from 1 to 3 kWh m–3, with the UV lamp accounting for most of the energy consumption. The gas diffusion electrode exhibited high efficiency for H2O2 production over extended periods and did not show a diminution in performance in any of the matrices. PMID:26039560

  18. Effects on temperature and acidic pre-treatment on Fenton-driven oxidation of MTBE-spent granular activated carbon

    EPA Science Inventory

    Temperature-dependent mechanisms in the Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was investigated. Prior to iron (Fe) amendment to the GAC, acid-treatment altered the surface chemistry of the GAC and lowered the p...

  19. Effects of Temperature and Acidic Pre-Treatment on Fenton-Driven Oxidation of MTBE-Spent Granular Activated Carbon

    EPA Science Inventory

    Temperature-dependent mechanisms in the Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was investigated. Prior to iron (Fe) amendment to the GAC, acid-treatment altered the surface chemistry of the GAC and lowered the pH ...

  20. An advanced tunnel oxide layer process for 65 nm NOR floating-gate flash memories

    NASA Astrophysics Data System (ADS)

    Chiu, Shengfen; Xu, Yue; Ji, Xiaoli; Liao, Yiming; Wu, Fuwei; Yan, Feng

    2015-10-01

    An advanced tunnel oxide layer process for 65 nm NOR-type floating-gate flash memory is proposed to improve tunnel oxide quality by an additive sacrificial oxide layer growth. The sacrificial oxide layer process effectively controls the thickness variation of tunnel oxide and improves the flatness of the SiO2/Si interface across the active area. The interface traps’ generation during program/erase cycling of flash cells is found to be reduced, and the reliability property is significantly improved as compared to flash cells without the sacrificial oxide layer process. The technology is applicable to further scaled floating-gate flash memories.

  1. Methane Uptake in Forest Soils is Driven by Diffusivity and Methane Oxidizer Community Size

    NASA Astrophysics Data System (ADS)

    Sullivan, B. W.; Hart, S. C.; Kolb, T. E.

    2008-12-01

    Upland forest soils are the only known terrestrial biological sink of methane, but the mechanisms controlling methane uptake are poorly understood. Methane uptake is the result of bacterial and archaeal 'methane oxidizer' activity. Temperature, water content, and substrate availability have all been described as potential mechanisms governing methane uptake in soils. We measured methane uptake in soil across two ecological different gradients in an attempt to determine controls on methane uptake in semi-arid soils. We measured the uptake of atmospheric methane in situ across a gradient of northern Arizona, USA ponderosa pine forest disturbance. This gradient included an unthinned, unburned forest, a mechanically thinned forest, and a former forest site that completely burned 10 years prior to measurements. In laboratory incubations, we measured potential methane uptake across a soil chronosequence of basalt-cinder derived soils from 0.001 to 3 million years old by exposing soils to 10x ambient levels of methane. This chronosequence has a gradient of soil texture, which will influence the air filled pore space, and consequently methane diffusion. Both gradients experience distinct dry and wet seasons during the growing season. Our field measurements suggest that methane uptake is greatest when the forest floor is thinnest and the soil is most dry. Our laboratory incubations suggest that, during the dry season, potential methane uptake is driven by diffusion, but that during the wet season potential methane uptake is a function of methane oxidizer community size. Methane uptake patterns across both gradients demonstrates the importance of diffusion and methane oxidizer community size as codominant controlling factors.

  2. Cerebral non-oxidative carbohydrate consumption in humans driven by adrenaline.

    PubMed

    Seifert, Thomas S; Brassard, Patrice; Jørgensen, Thomas B; Hamada, Ahmad J; Rasmussen, Peter; Quistorff, Bjørn; Secher, Niels H; Nielsen, Henning B

    2009-01-15

    During brain activation, the decrease in the ratio between cerebral oxygen and carbohydrate uptake (6 O(2)/(glucose + (1)/(2) lactate); the oxygen-carbohydrate index, OCI) is attenuated by the non-selective beta-adrenergic receptor antagonist propranolol, whereas OCI remains unaffected by the beta(1)-adrenergic receptor antagonist metroprolol. These observations suggest involvement of a beta(2)-adrenergic mechanism in non-oxidative metabolism for the brain. Therefore, we evaluated the effect of adrenaline (0.08 microg kg(-1) min(-1) i.v. for 15 min) and noradrenaline (0.5, 0.1 and 0.15 microg kg(-1) min(-1) i.v. for 20 min) on the arterial to internal jugular venous concentration differences (a-v diff) of O(2), glucose and lactate in healthy humans. Adrenaline (n = 10) increased the arterial concentrations of O(2), glucose and lactate (P < 0.05) and also increased the a-v diff for glucose from 0.6 +/- 0.1 to 0.8 +/- 0.2 mM (mean +/- s.d.; P < 0.05). The a-v diff for lactate shifted from a net cerebral release to an uptake and OCI was lowered from 5.1 +/- 1.5 to 3.6 +/- 0.4 (P < 0.05) indicating an 8-fold increase in the rate of non-oxidative carbohydrate uptake during adrenaline infusion (P < 0.01). Conversely, noradrenaline (n = 8) did not affect the OCI despite an increase in the a-v diff for glucose (P < 0.05). These results support that non-oxidative carbohydrate consumption for the brain is driven by a beta(2)-adrenergic mechanism, giving neurons an abundant provision of energy when plasma adrenaline increases.

  3. Remediation of a winery wastewater combining aerobic biological oxidation and electrochemical advanced oxidation processes.

    PubMed

    Moreira, Francisca C; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

    2015-05-15

    Apart from a high biodegradable fraction consisting of organic acids, sugars and alcohols, winery wastewaters exhibit a recalcitrant fraction containing high-molecular-weight compounds as polyphenols, tannins and lignins. In this context, a winery wastewater was firstly subjected to a biological oxidation to mineralize the biodegradable fraction and afterwards an electrochemical advanced oxidation process (EAOP) was applied in order to mineralize the refractory molecules or transform them into simpler ones that can be further biodegraded. The biological oxidation led to above 97% removals of dissolved organic carbon (DOC), chemical oxygen demand (COD) and 5-day biochemical oxygen demand (BOD5), but was inefficient on the degradation of a bioresistant fraction corresponding to 130 mg L(-1) of DOC, 380 mg O2 L(-1) of COD and 8.2 mg caffeic acid equivalent L(-1) of total dissolved polyphenols. Various EAOPs such as anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF), UVA photoelectro-Fenton (PEF) and solar PEF (SPEF) were then applied to the recalcitrant effluent fraction using a 2.2 L lab-scale flow plant containing an electrochemical cell equipped with a boron-doped diamond (BDD) anode and a carbon-PTFE air-diffusion cathode and coupled to a photoreactor with compound parabolic collectors (CPCs). The influence of initial Fe(2+) concentration and current density on the PEF process was evaluated. The relative oxidative ability of EAOPs increased in the order AO-H2O2 < EF < PEF ≤ SPEF. The SPEF process using an initial Fe(2+) concentration of 35 mg L(-1), current density of 25 mA cm(-2), pH of 2.8 and 25 °C reached removals of 86% on DOC and 68% on COD after 240 min, regarding the biologically treated effluent, along with energy consumptions of 45 kWh (kg DOC)(-1) and 5.1 kWh m(-3). After this coupled treatment, color, odor, COD, BOD5, NH4(+), NO3(-) and SO4(2-) parameters complied with the legislation targets and, in addition, a total

  4. Oxidative decomposition of p-nitroaniline in water by solar photo-Fenton advanced oxidation process.

    PubMed

    Sun, Jian-Hui; Sun, Sheng-Peng; Fan, Mao-Hong; Guo, Hui-Qin; Lee, Yi-Fan; Sun, Rui-Xia

    2008-05-01

    The degradation of p-nitroaniline (PNA) in water by solar photo-Fenton advanced oxidation process was investigated in this study. The effects of different reaction parameters including pH value of solutions, dosages of hydrogen peroxide and ferrous ion, initial PNA concentration and temperature on the degradation of PNA have been studied. The optimum conditions for the degradation of PNA in water were considered to be: the pH value at 3.0, 10 mmol L(-1) H(2)O(2), 0.05 mmol L(-1) Fe(2+), 0.072-0.217 mmol L(-1) PNA and temperature at 20 degrees C. Under the optimum conditions, the degradation efficiencies of PNA were more than 98% within 30 min reaction. The degradation characteristic of PNA showed that the conjugated pi systems of the aromatic ring in PNA molecules were effectively destructed. The experimental results indicated solar photo-Fenton process has more advantages compared with classical Fenton process, such as higher oxidation power, wider working pH range, lower ferrous ion usage, etc. Furthermore, the present study showed the potential use of solar photo-Fenton process for PNA containing wastewater treatment.

  5. Chemical instability of graphene oxide following exposure to highly reactive radicals in advanced oxidation processes.

    PubMed

    Wang, Zhaohui; Sun, Linyan; Lou, Xiaoyi; Yang, Fei; Feng, Min; Liu, Jianshe

    2017-12-01

    The rapidly increasing and widespread use of graphene oxide (GO) as catalyst supports, requires further understanding of its chemical stability in advanced oxidation processes (AOPs). In this study, UV/H2O2 and UV/persulfate (UV/PS) processes were selected to test the chemical instability of GO in terms of their performance in producing highly reactive hydroxyl radicals (OH) and sulfate radicals (SO4(-)), respectively. The degradation intermediates were characterized using UV-visible absorption spectra (UV-vis), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, and matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Experimental data indicate that UV/PS process was more effective in enhancing GO degradation than the UV/H2O2 system. The overall oxygen-containing functionalities (e.g. CO, CO and OCO groups) dramatically declined. After radical attack, sheet-like GO was destructed into lots of flakes and some low-molecular-weight molecules were detected. The results suggest GO is most vulnerable against SO4(-) radical attack, which deserves special attention while GO acts as a catalyst support or even as a catalyst itself. Therefore, stability of GO and its derivatives should be carefully assessed before they are applied to SO4(-)-based AOPs. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Demonstrating Advanced Oxidation Coupled with Biodegradation for Removal of Carbamazepine (WERF Report INFR6SG09)

    EPA Science Inventory

    Carbamazepine is an anthropogenic pharmaceutical found in wastewater effluents that is quite resistant to removal by conventional wastewater treatment processes. Hydroxyl radical-based advanced oxidation processes can transform carbamazepine into degradation products but cannot m...

  7. Demonstrating Advanced Oxidation Coupled with Biodegradation for Removal of Carbamazepine (WERF Report INFR6SG09)

    EPA Science Inventory

    Carbamazepine is an anthropogenic pharmaceutical found in wastewater effluents that is quite resistant to removal by conventional wastewater treatment processes. Hydroxyl radical-based advanced oxidation processes can transform carbamazepine into degradation products but cannot m...

  8. IRON-PEROXYMONOSULFATE: A NOVEL SULFATE RADICAL BASED ADVANCED OXIDATION TECHNOLOGY FOR DEGRADATION OF PCBS

    EPA Science Inventory

    This study investigates the degradation of recalcitrant polychlorinated biphenyl (PCBs) using sulfate radical-based advanced oxidation technologies. Sulfate radicals are generated through coupling of peroxymonosulfate (PMS) with iron (Fe(II), Fe(III)). Sulfate radicals have very ...

  9. Evaluation of Resin Dissolution Using an Advanced Oxidation Process - 13241

    SciTech Connect

    Goulart de Araujo, Leandro; Vicente de Padua Ferreira, Rafael; Takehiro Marumo, Julio; Passos Piveli, Roque; Campos, Fabio

    2013-07-01

    The ion-exchange resin is widely used in nuclear reactors, in cooling water purification and removing radioactive elements. Because of the long periods of time inside the reactor system, the resin becomes radioactive. When the useful life of them is over, its re-utilization becomes inappropriate, and for this reason, the resin is considered radioactive waste. The most common method of treatment is the immobilization of spent ion exchange resin in cement in order to form a solid monolithic matrix, which reduces the radionuclides release into the environment. However, the characteristic of contraction and expansion of the resin limits its incorporation in 10%, resulting in high cost in its direct immobilization. Therefore, it is recommended the utilization of a pre-treatment, capable of reducing the volume and degrading the resin, which would increase the load capacity in the immobilization. This work aims to develop a method of degradation of ion spent resins from the nuclear research reactor of Nuclear and Energy Research Institute (IPEN/CNEN-SP), Brazil, using the Advanced Oxidative Process (AOP) with Fenton's reagent (hydrogen peroxide and ferrous sulphate as catalyst). The resin evaluated was a mixture of cationic (IR 120P) and anionic (IRA 410) resins. The reactions were conducted by varying the concentration of the catalyst (25, 50, 100 e 150 mM) and the volume of the hydrogen peroxide, at three different temperatures, 50, 60 and 70 deg. C. The time of reaction was three hours. Total organic carbon content was determined periodically in order to evaluate the degradation as a function of time. The concentration of 50 mM of catalyst was the most effective in degrading approximately 99%, using up to 330 mL of hydrogen peroxide. The most effective temperature was about 60 deg. C, because of the decomposition of hydrogen peroxide in higher temperatures. TOC content was influenced by the concentration of the catalyst, interfering in the beginning of the degradation

  10. Advances in NMR Spectroscopy for Lipid Oxidation Assessment

    USDA-ARS?s Scientific Manuscript database

    Although there are many analytical methods developed for the assessment of lipid oxidation, different analytical methods often give different, sometimes even contradictory, results. The reason for this inconsistency is that although there are many different kinds of oxidation products, most methods ...

  11. Nitric Oxide-Driven Hypoxia Initiates Synovial Angiogenesis, Hyperplasia and Inflammatory Lesions in Mice

    PubMed Central

    Bao, Fei; Wu, Pei; Xiao, Na; Qiu, Frank; Zeng, Qing-Ping

    2012-01-01

    Background Rheumatoid arthritis (RA) is an inflammatory articular disease with cartilage and bone damage due to hyperplasic synoviocyte invasion and subsequent matrix protease digestion. Although monoclonal antibodies against tumor necrosis factor alpha (TNFα) have been approved for clinical use in patients with RA, desired therapeutic regimens suitable for non-responders are still unavailable because etiological initiators leading to RA remain enigmatic and unidentified. Methodology/Principal Findings Bacteria-induced arthritis (BIA) that simulates collagen-induced arthritis (CIA) is developed in mice upon daily live bacterial feeding. The morphological lesions of paw erythema and edema together with the histological alterations of synovial hyperplasia and lymphocytic infiltration emerge as the early-phase manifestations of BIA and CIA. Bacteria- or collagen-mediated global upregulation of pro-inflammatory cytokines is accompanied by the burst of nitric oxide (NO). Elevation of the serum NO level is correlated with decline of the blood oxygen saturation percentage (SpO2), reflecting a hypoxic consequence during development towards arthritis. NO-driven hypoxia is further evident from a positive relationship between NO and lactic acid (LA), an end product from glycolysis. Upregulation of hypoxia inducible factor 1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF) validates hypoxia-induced angiogenesis in the inflamed synovium of modeling mice. Administration of the NO donor compound sodium nitroprusside (SNP) causes articular inflammation by inducing synovial hypoxia. Anti-bacteria by the antibiotic cefotaxime and/or the immunosuppressant rapamycin or artesunate that also inhibits nitric oxide synthase (NOS) can abrogate NO production, mitigate hypoxia, and considerably ameliorate or even completely abort synovitis, hence highlighting that NO may serve as an initiator of inflammatory arthritis. Conclusions/Significance Like collagen, bacteria also

  12. High-performance photoelectrochemical cells based on a binuclear ruthenium catalyst for visible-light-driven water oxidation.

    PubMed

    Zhang, Linlin; Gao, Yan; Ding, Xin; Yu, Ze; Sun, Licheng

    2014-10-01

    Two photoanodes based on a binuclear (2) and a mononuclear ruthenium (3) water oxidation catalysts were assembled in combination with a molecular photosensitizer (1) by using a co-adsorption method. The anodes were used in dye-sensitized photoelectrochemical cells (DS-PECs) for visible-light-driven water splitting. A DS-PEC device using TiO2 (1+2) as working electrode (WE) exhibits better performance than TiO2 (1+3) as WE in light-driven water splitting. Detailed photoelectrochemical studies on these DS-PEC devices are discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Structure evolution of graphene oxide during thermally driven phase transformation: is the oxygen content really preserved?

    PubMed

    Sun, Pengzhan; Wang, Yanlei; Liu, He; Wang, Kunlin; Wu, Dehai; Xu, Zhiping; Zhu, Hongwei

    2014-01-01

    A mild annealing procedure was recently proposed for the scalable enhancement of graphene oxide (GO) properties with the oxygen content preserved, which was demonstrated to be attributed to the thermally driven phase separation. In this work, the structure evolution of GO with mild annealing is closely investigated. It reveals that in addition to phase separation, the transformation of oxygen functionalities also occurs, which leads to the slight reduction of GO membranes and furthers the enhancement of GO properties. These results are further supported by the density functional theory based calculations. The results also show that the amount of chemically bonded oxygen atoms on graphene decreases gradually and we propose that the strongly physisorbed oxygen species constrained in the holes and vacancies on GO lattice might be responsible for the preserved oxygen content during the mild annealing procedure. The present experimental results and calculations indicate that both the diffusion and transformation of oxygen functional groups might play important roles in the scalable enhancement of GO properties.

  14. Structure Evolution of Graphene Oxide during Thermally Driven Phase Transformation: Is the Oxygen Content Really Preserved?

    PubMed Central

    Sun, Pengzhan; Wang, Yanlei; Liu, He; Wang, Kunlin; Wu, Dehai; Xu, Zhiping; Zhu, Hongwei

    2014-01-01

    A mild annealing procedure was recently proposed for the scalable enhancement of graphene oxide (GO) properties with the oxygen content preserved, which was demonstrated to be attributed to the thermally driven phase separation. In this work, the structure evolution of GO with mild annealing is closely investigated. It reveals that in addition to phase separation, the transformation of oxygen functionalities also occurs, which leads to the slight reduction of GO membranes and furthers the enhancement of GO properties. These results are further supported by the density functional theory based calculations. The results also show that the amount of chemically bonded oxygen atoms on graphene decreases gradually and we propose that the strongly physisorbed oxygen species constrained in the holes and vacancies on GO lattice might be responsible for the preserved oxygen content during the mild annealing procedure. The present experimental results and calculations indicate that both the diffusion and transformation of oxygen functional groups might play important roles in the scalable enhancement of GO properties. PMID:25372142

  15. Orbital driven impurity spin effect on the magnetic order of quasi-3D cupric oxide.

    PubMed

    Ganga, B G; Santhosh, P N; Nanda, B R K

    2017-04-20

    Density functional calculations are performed to study the magnetic order of the severely distorted square planar cupric oxide (CuO) and local spin disorder in it in the presence of the transition metal impurities M (=Cr, Mn, Fe, Co and Ni). The distortion in the crystal structure, arisen to reduce the band energy by minimizing the covalent interaction, creates two crisscrossing zigzag spin-1/2 chains. From the spin dimer analysis we find that while the spin chain along [Formula: see text] has strong Heisenberg type antiferromagnetic coupling (J ~ 127 meV), along [Formula: see text] it exhibits weak, but robust, ferromagnetic coupling (J ~ 9 meV) mediated by reminiscent p-d covalent interactions. The impurity effect on the magnetic ordering is independent of M and purely orbital driven. If the given spin-state of M is such that the [Formula: see text] orbital is spin-polarized, then the original long-range ordering is maintained. However, if [Formula: see text] orbital is unoccupied, the absence of corresponding covalent interaction breaks the weak ferromagnetic coupling and a spin-flip takes place at the impurity site leading to breakdown of the long range magnetic ordering.

  16. Orbital driven impurity spin effect on the magnetic order of quasi-3D cupric oxide

    NASA Astrophysics Data System (ADS)

    Ganga, B. G.; Santhosh, P. N.; Nanda, B. R. K.

    2017-04-01

    Density functional calculations are performed to study the magnetic order of the severely distorted square planar cupric oxide (CuO) and local spin disorder in it in the presence of the transition metal impurities M (=Cr, Mn, Fe, Co and Ni). The distortion in the crystal structure, arisen to reduce the band energy by minimizing the covalent interaction, creates two crisscrossing zigzag spin-1/2 chains. From the spin dimer analysis we find that while the spin chain along ≤ft[1 0 \\bar{1}\\right] has strong Heisenberg type antiferromagnetic coupling (J ~ 127 meV), along ≤ft[1 0 1\\right] it exhibits weak, but robust, ferromagnetic coupling (J ~ 9 meV) mediated by reminiscent p-d covalent interactions. The impurity effect on the magnetic ordering is independent of M and purely orbital driven. If the given spin-state of M is such that the {{d}{{x2}-{{y}2}}} orbital is spin-polarized, then the original long-range ordering is maintained. However, if {{d}{{x2}-{{y}2}}} orbital is unoccupied, the absence of corresponding covalent interaction breaks the weak ferromagnetic coupling and a spin-flip takes place at the impurity site leading to breakdown of the long range magnetic ordering.

  17. Importance of Plasmonic Heating on Visible Light Driven Photocatalysis of Gold Nanoparticle Decorated Zinc Oxide Nanorods

    PubMed Central

    Bora, Tanujjal; Zoepfl, David; Dutta, Joydeep

    2016-01-01

    Herein we explore the role of localized plasmonic heat generated by resonantly excited gold (Au) NPs on visible light driven photocatalysis process. Au NPs are deposited on the surface of vertically aligned zinc oxide nanorods (ZnO NRs). The localized heat generated by Au NPs under 532 nm continuous laser excitation (SPR excitation) was experimentally probed using Raman spectroscopy by following the phonon modes of ZnO. Under the resonant excitation the temperature at the surface of the Au-ZnO NRs reaches up to about 300 °C, resulting in almost 6 times higher apparent quantum yield (AQY) for photocatalytic degradation of methylene blue (MB) compared to the bare ZnO NRs. Under solar light irradiation the Au-ZnO NRs demonstrated visible light photocatalytic activity twice that of what was achieved with bare ZnO NRs, while significantly reduced the activation energy required for the photocatalytic reactions allowing the reactions to occur at a faster rate. PMID:27242172

  18. Halogenated earth abundant metalloporphyrins as photostable sensitizers for visible-light-driven water oxidation in a neutral phosphate buffer solution.

    PubMed

    Chen, Hung-Cheng; Reek, Joost N H; Williams, René M; Brouwer, Albert M

    2016-06-01

    Very photostable tetrachloro-metalloporphyrins were developed as sensitizers for visible-light-driven water oxidation coupled to cobalt based water-oxidation catalysts in concentrated (0.1 M) phosphate buffer solution. Potassium persulfate (K2S2O8) acts as a sacrificial electron acceptor to oxidize the metalloporphyrin photosensitizers in their excited states. The radical cations thus produced drive the cobalt based water-oxidation catalysts: Co4O4-cubane and Co(NO3)2 as pre-catalyst for cobalt-oxide (CoOx) nanoparticles. Two different metalloporphyrins (Cu(ii) and Ni(ii)) both showed very high photostability in the photocatalytic reaction, as compared to non-halogenated analogues. This indicates that photostability primarily depends on the substitution of the porphyrin macrocycle, not on the central metal. Furthermore, our molecular design strategy not only positively increases the electrochemical potential by 120-140 mV but also extends the absorption spectrum up to ∼600 nm. As a result, the solar photon capturing abilities of halogenated metalloporphyrins (Cu(ii) and Ni(ii)) are comparable to that of the natural photosynthetic pigment, chlorophyll a. We successfully demonstrate long-term (>3 h) visible-light-driven water oxidation using our molecular system based on earth-abundant (first-row transition) metals in concentrated phosphate buffer solution.

  19. Nox control for high nitric oxide concentration flows through combustion-driven reduction

    DOEpatents

    Yeh, James T.; Ekmann, James M.; Pennline, Henry W.; Drummond, Charles J.

    1989-01-01

    An improved method for removing nitrogen oxides from concentrated waste gas streams, in which nitrogen oxides are ignited with a carbonaceous material in the presence of substoichiometric quantities of a primary oxidant, such as air. Additionally, reductants may be ignited along with the nitrogen oxides, carbonaceous material and primary oxidant to achieve greater reduction of nitrogen oxides. A scrubber and regeneration system may also be included to generate a concentrated stream of nitrogen oxides from flue gases for reduction using this method.

  20. Diagnostic Overview of the C-2U Advanced Beam-Driven Field-Reversed Configuration Plasma Experiment

    NASA Astrophysics Data System (ADS)

    Thompson, Matthew; Gota, Hiroshi; Putvinski, Sergei; Tuszewski, Michel; Binderbauer, Michl; The TAE Team

    2015-11-01

    The C-2U experiment at Tri Alpha Energy seeks to study the evolution of advanced beam-driven field-reversed configuration (FRC) plasmas sustained by neutral beam (NB) injection for 5 + ms. Data on the FRC plasma performance is provided by a comprehensive suite of diagnostics including magnetic sensors, interferometry, Thomson scattering, spectroscopy, bolometry, reflectometry, and NB-related fast-ion/neutral diagnostics. While many of these diagnostic systems were inherited from the preceding experiment C-2, C-2U has a variety of new and upgraded diagnostic systems: multi-chord far-infrared polarimetry, multiple fast imaging cameras with selectable atomic line filters, proton detector arrays, and 100 channel bolometer units capable of observing multiple regions of the spectrum simultaneously. In addition, extensive ongoing work focuses on advanced methods of measuring separatrix shape that will both improve accuracy and facilitate active control of the FRC plasma.

  1. Study of Plasma Liner Driven Magnetized Target Fusion Via Advanced Simulations

    SciTech Connect

    Samulyak, Roman V.; Parks, Paul

    2013-08-31

    The feasibility of the plasma liner driven Magnetized Target Fusion (MTF) via terascale numerical simulations will be assessed. In the MTF concept, a plasma liner, formed by merging of a number (60 or more) of radial, highly supersonic plasma jets, implodes on the target in the form of two compact plasma toroids, and compresses it to conditions of the fusion ignition. By avoiding major difficulties associated with both the traditional laser driven inertial confinement fusion and solid liner driven MTF, the plasma liner driven MTF potentially provides a low-cost and fast R&D path towards the demonstration of practical fusion energy. High fidelity numerical simulations of full nonlinear models associated with the plasma liner MTF using state-of-art numerical algorithms and terascale computing are necessary in order to resolve uncertainties and provide guidance for future experiments. At Stony Brook University, we have developed unique computational capabilities that ideally suite the MTF problem. The FronTier code, developed in collaboration with BNL and LANL under DOE funding including SciDAC for the simulation of 3D multi-material hydro and MHD flows, has beenbenchmarked and used for fundamental and engineering problems in energy science applications. We have performed 3D simulations of converging supersonic plasma jets, their merger and the formation of the plasma liner, and a study of the corresponding oblique shock problem. We have studied the implosion of the plasma liner on the magnetized plasma target by resolving Rayleigh-Taylor instabilities in 2D and 3D and other relevant physics and estimate thermodynamic conditions of the target at the moment of maximum compression and the hydrodynamic efficiency of the method.

  2. Advances in Statistical and Deterministic Modeling of Wind-Driven Seas

    DTIC Science & Technology

    2011-09-30

    Wind-Driven Seas Zakharov Vladimir, Pushkarev Andrei Waves and Solitons LLC 1719 W. Marlette Ave. Phoenix, AZ 85015 phone: +1 (602) 748-4286 e...NAME(S) AND ADDRESS(ES) Waves and Solitons LLC,1719 W. Marlette Ave,Phoenix,AZ,85015 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING...decrement, kN – spectral density of wave action . Our numerical and analytical results show that kk NΓ and kF surpass conventional parameterizations

  3. Advanced oxide dispersion strengthened sheet alloys for improved combustor durability

    NASA Technical Reports Server (NTRS)

    Henricks, R. J.

    1981-01-01

    Burner design modifications that will take advantage of the improved creep and cyclic oxidation resistance of oxide dispersion strengthened (ODS) alloys while accommodating the reduced fatigue properties of these materials were evaluated based on preliminary analysis and life predictions, on construction and repair feasibility, and on maintenance and direct operating costs. Two designs - the film cooled, segmented louver and the transpiration cooled, segmented twin Wall - were selected for low cycle fatigue (LCF) component testing. Detailed thermal and structural analysis of these designs established the strain range and temprature at critical locations resulting in predicted lives of 10,000 cycles for MA 956 alloy. The ODs alloys, MA 956 and HDA 8077, demonstrated a 167 C (300 F) temperature advantage over Hastelloy X alloy in creep strength and oxidation resistance. The MA 956 alloy was selected for mechanical property and component test evaluations. The MA 956 alloy was superior to Hastelloy X in LCF component testing of the film cooled, segmented louver design.

  4. Recent Advances on Nitric Oxide in the Upper Airways.

    PubMed

    Maniscalco, Mauro; Bianco, Andrea; Mazzarella, Gennaro; Motta, Andrea

    2016-01-01

    Exhaled nitric oxide (NO) originates from the upper airways, and takes action, to varying extents, in regulation, protection and defense, as well as in noxious processes. Nitric oxide retains important functions in a wide range of physiological and pathophysiological processes of the human body, including vaso-regulation, antimicrobial activity, neurotransmission and respiration. This review article reports the ongoing investigations regarding the source, biology and relevance of NO within upper respiratory tract. In addition, we discuss the role of NO, originating from nasal and paranasal sinuses, in inflammatory disorders such as allergic rhinitis, sinusitis, primary ciliary dyskinesia, and cystic fibrosis.

  5. Electrocatalyst advances for hydrogen oxidation in phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Stonehart, P.

    1984-01-01

    The important considerations that presently exist for achieving commercial acceptance of fuel cells are centered on cost (which translates to efficiency) and lifetime. This paper addresses the questions of electrocatalyst utilization within porous electrode structures and the preparation of low-cost noble metal electrocatalyst combinations with extreme dispersions of the metal. Now that electrocatalyst particles can be prepared with dimensions of 10 A, either singly or in alloy combinations, a very large percentage of the noble metal atoms in a crystallite are available for reaction. The cost savings for such electrocatalysts in the present commercially driven environment are considerable.

  6. Electrocatalyst advances for hydrogen oxidation in phosphoric acid fuel cells

    NASA Technical Reports Server (NTRS)

    Stonehart, P.

    1984-01-01

    The important considerations that presently exist for achieving commercial acceptance of fuel cells are centered on cost (which translates to efficiency) and lifetime. This paper addresses the questions of electrocatalyst utilization within porous electrode structures and the preparation of low-cost noble metal electrocatalyst combinations with extreme dispersions of the metal. Now that electrocatalyst particles can be prepared with dimensions of 10 A, either singly or in alloy combinations, a very large percentage of the noble metal atoms in a crystallite are available for reaction. The cost savings for such electrocatalysts in the present commercially driven environment are considerable.

  7. Photocatalytic oxidation of organic dyes with visible-light-driven codoped TiO2 photocatalysts

    NASA Astrophysics Data System (ADS)

    Zhang, Dongfang; Zeng, Fanbin

    2011-06-01

    A novel copper (II) and zinc (II) codoped TiO2 photocatalyst was synthesized by a modified sol-gel method using titanium (IV) isopropoxide, Zn(NO3)2 · 6H2O and copper(Il) nitrate as precursors. The samples were characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS) and photo-luminescence spectra (PL). The XRD results showed undoped and Zn, Cu-codoped TiO2 nanoparticles mainly including anatase phase and a tiny amount of Zn- and Cu-oxides exist in the mixed system, which is attributed to the decomposition of copper and zinc nitrates in the TiO2 gel to form CuO and ZnO and randomly dispersed on the TiO2 surface. On the basis of the optical characterization results, we found that the codoping of copper (II) and zinc (II) resulted a red shift of adsorption and lower recombination probability between electrons and holes, which were the reasons for high photocatalytic activity of Zn, Cu-codoped TiO2 nanoparticles under visible light (λ > 400 nm). The photocatalytic activity of samples was tested for degradation of methyl orange (MO) in solutions. The results indicated that the visible-light driven capability of the codoped catalyst were much higher than that of the pure TiO2 catalyst under visible irradiation. Because of the synergetic effect of copper (II) and zinc (II) element, the Zn, Cu-codoped TiO2 catalyst will show higher quantum yield and enhance absorption of visible light. In the end, a key mechanism was proposed in order to account for the enhanced activity.

  8. Thermochemical Compatibility and Oxidation Resistance of Advanced LWR Fuel Cladding

    DOE PAGES

    Besmann, T. M.; Yamamoto, Y.; Unocic, K. A.

    2016-06-21

    We assessed the thermochemical compatibility of potential replacement cladding materials for zirconium alloys in light water reactors. Considered were FeCrAl steel (similar to Kanthal APMT), Nb-1%Zr (similar to PWC-11), and a hybrid SiC-composite with a metallic barrier layer. The niobium alloy was also seen as requiring an oxidation protective layer, and a diffusion silicide was investigated. Metallic barrier layers for the SiC-composite reviewed included a FeCrAl alloy, Nb-1%Zr, and chromium. Thermochemical calculations were performed to determine oxidation behavior of the materials in steam, and for hybrid SiC-composites possible interactions between the metallic layer and SiC. Additionally, experimental exposures of SiC-alloymore » reaction couples at 673K, 1073K, and 1273K for 168 h in an inert atmosphere were made and microanalysis performed. Whereas all materials were determined to oxidize under higher oxygen partial pressures in the steam environment, these varied by material with expected protective oxides forming. Finally, the computed and experimental results indicate the formation of liquid phase eutectic in the FeCrAl-SiC system at the higher temperatures.« less

  9. Thermochemical Compatibility and Oxidation Resistance of Advanced LWR Fuel Cladding

    SciTech Connect

    Besmann, T. M.; Yamamoto, Y.; Unocic, K. A.

    2016-06-21

    We assessed the thermochemical compatibility of potential replacement cladding materials for zirconium alloys in light water reactors. Considered were FeCrAl steel (similar to Kanthal APMT), Nb-1%Zr (similar to PWC-11), and a hybrid SiC-composite with a metallic barrier layer. The niobium alloy was also seen as requiring an oxidation protective layer, and a diffusion silicide was investigated. Metallic barrier layers for the SiC-composite reviewed included a FeCrAl alloy, Nb-1%Zr, and chromium. Thermochemical calculations were performed to determine oxidation behavior of the materials in steam, and for hybrid SiC-composites possible interactions between the metallic layer and SiC. Additionally, experimental exposures of SiC-alloy reaction couples at 673K, 1073K, and 1273K for 168 h in an inert atmosphere were made and microanalysis performed. Whereas all materials were determined to oxidize under higher oxygen partial pressures in the steam environment, these varied by material with expected protective oxides forming. Finally, the computed and experimental results indicate the formation of liquid phase eutectic in the FeCrAl-SiC system at the higher temperatures.

  10. Thermochemical Compatibility and Oxidation Resistance of Advanced LWR Fuel Cladding

    SciTech Connect

    Besmann, T. M.; Yamamoto, Y.; Unocic, K. A.

    2016-06-21

    We assessed the thermochemical compatibility of potential replacement cladding materials for zirconium alloys in light water reactors. Considered were FeCrAl steel (similar to Kanthal APMT), Nb-1%Zr (similar to PWC-11), and a hybrid SiC-composite with a metallic barrier layer. The niobium alloy was also seen as requiring an oxidation protective layer, and a diffusion silicide was investigated. Metallic barrier layers for the SiC-composite reviewed included a FeCrAl alloy, Nb-1%Zr, and chromium. Thermochemical calculations were performed to determine oxidation behavior of the materials in steam, and for hybrid SiC-composites possible interactions between the metallic layer and SiC. Additionally, experimental exposures of SiC-alloy reaction couples at 673K, 1073K, and 1273K for 168 h in an inert atmosphere were made and microanalysis performed. Whereas all materials were determined to oxidize under higher oxygen partial pressures in the steam environment, these varied by material with expected protective oxides forming. Finally, the computed and experimental results indicate the formation of liquid phase eutectic in the FeCrAl-SiC system at the higher temperatures.

  11. Novel fibrous catalyst in advanced oxidation of photographic processing effluents.

    PubMed

    Yang, Zhuxian; Ishtchenko, Vera V; Huddersman, Katherine D

    2006-01-01

    A novel fibrous catalyst was used to destroy the pollutants in Kodak Non-Silver-Bearing (NSB) photographic processing effluents with high chemical oxygen demand (COD) value. The oxidation activity of the catalyst was evaluated in terms of COD reduction of the effluent. The effects of concentrations of hydrogen peroxide and effluent, amount of catalyst, reaction time and temperature on the COD reduction were studied. In addition, the combination of catalysis with UV treatment on the COD reduction of the effluent was also investigated. Based on the experimental results, room temperature is preferred for the catalytic oxidation of NSB effluent. It was found that COD reduction of the effluent depends on the amount of hydrogen peroxide added to the feed in relation to the mass of catalyst used. Significant COD reduction (up to 52%) is achieved after 4 hours of catalytic treatment. Extending the duration of catalysis up to 24 hours gives further slight decrease in COD value.

  12. In vitro oxidation of fibrinogen promotes functional alterations and formation of advanced oxidation protein products, an inflammation mediator.

    PubMed

    Torbitz, Vanessa Dorneles; Bochi, Guilherme Vargas; de Carvalho, José Antônio Mainardi; de Almeida Vaucher, Rodrigo; da Silva, José Edson Paz; Moresco, Rafael Noal

    2015-01-01

    Fibrinogen (FB) is a soluble blood plasma protein and is a key molecule involved in coagulation. Oxidative modification of proteins, such as the formation of advanced oxidation protein products (AOPP), a heterogeneous family of protein compounds structurally modified and derived from oxidative stress, may be associated with the pathophysiology of a number of chronic inflammatory diseases. Therefore, the aim of this study was to determine whether the formation of this mediator of inflammation occurs from FB and whether its generation is associated with structural changes. Results of the present study suggest that the oxidation of FB may provoke the formation of AOPP, which in turn, may promote functional alterations in FB, thus causing changes in its structural domains and increasing its procoagulant activity.

  13. Advances in metal-induced oxidative stress and human disease.

    PubMed

    Jomova, Klaudia; Valko, Marian

    2011-05-10

    Detailed studies in the past two decades have shown that redox active metals like iron (Fe), copper (Cu), chromium (Cr), cobalt (Co) and other metals undergo redox cycling reactions and possess the ability to produce reactive radicals such as superoxide anion radical and nitric oxide in biological systems. Disruption of metal ion homeostasis may lead to oxidative stress, a state where increased formation of reactive oxygen species (ROS) overwhelms body antioxidant protection and subsequently induces DNA damage, lipid peroxidation, protein modification and other effects, all symptomatic for numerous diseases, involving cancer, cardiovascular disease, diabetes, atherosclerosis, neurological disorders (Alzheimer's disease, Parkinson's disease), chronic inflammation and others. The underlying mechanism of action for all these metals involves formation of the superoxide radical, hydroxyl radical (mainly via Fenton reaction) and other ROS, finally producing mutagenic and carcinogenic malondialdehyde (MDA), 4-hydroxynonenal (HNE) and other exocyclic DNA adducts. On the other hand, the redox inactive metals, such as cadmium (Cd), arsenic (As) and lead (Pb) show their toxic effects via bonding to sulphydryl groups of proteins and depletion of glutathione. Interestingly, for arsenic an alternative mechanism of action based on the formation of hydrogen peroxide under physiological conditions has been proposed. A special position among metals is occupied by the redox inert metal zinc (Zn). Zn is an essential component of numerous proteins involved in the defense against oxidative stress. It has been shown, that depletion of Zn may enhance DNA damage via impairments of DNA repair mechanisms. In addition, Zn has an impact on the immune system and possesses neuroprotective properties. The mechanism of metal-induced formation of free radicals is tightly influenced by the action of cellular antioxidants. Many low-molecular weight antioxidants (ascorbic acid (vitamin C), alpha

  14. Advanced oxidation protein products (AOPP) for monitoring oxidative stress in critically ill patients: a simple, fast and inexpensive automated technique.

    PubMed

    Selmeci, László; Seres, Leila; Antal, Magda; Lukács, Júlia; Regöly-Mérei, Andrea; Acsády, György

    2005-01-01

    Oxidative stress is known to be involved in many human pathological processes. Although there are numerous methods available for the assessment of oxidative stress, most of them are still not easily applicable in a routine clinical laboratory due to the complex methodology and/or lack of automation. In research into human oxidative stress, the simplification and automation of techniques represent a key issue from a laboratory point of view at present. In 1996 a novel oxidative stress biomarker, referred to as advanced oxidation protein products (AOPP), was detected in the plasma of chronic uremic patients. Here we describe in detail an automated version of the originally published microplate-based technique that we adapted for a Cobas Mira Plus clinical chemistry analyzer. AOPP reference values were measured in plasma samples from 266 apparently healthy volunteers (university students; 81 male and 185 female subjects) with a mean age of 21.3 years (range 18-33). Over a period of 18 months we determined AOPP concentrations in more than 300 patients in our department. Our experiences appear to demonstrate that this technique is especially suitable for monitoring oxidative stress in critically ill patients (sepsis, reperfusion injury, heart failure) even at daily intervals, since AOPP exhibited rapid responses in both directions. We believe that the well-established relationship between AOPP response and induced damage makes this simple, fast and inexpensive automated technique applicable in daily routine laboratory practice for assessing and monitoring oxidative stress in critically ill or other patients.

  15. Nanostructured metal oxide-based materials as advanced anodes for lithium-ion batteries.

    PubMed

    Wu, Hao Bin; Chen, Jun Song; Hng, Huey Hoon; Lou, Xiong Wen David

    2012-04-21

    The search for new electrode materials for lithium-ion batteries (LIBs) has been an important way to satisfy the ever-growing demands for better performance with higher energy/power densities, improved safety and longer cycle life. Nanostructured metal oxides exhibit good electrochemical properties, and they are regarded as promising anode materials for high-performance LIBs. In this feature article, we will focus on three different categories of metal oxides with distinct lithium storage mechanisms: tin dioxide (SnO(2)), which utilizes alloying/dealloying processes to reversibly store/release lithium ions during charge/discharge; titanium dioxide (TiO(2)), where lithium ions are inserted/deinserted into/out of the TiO(2) crystal framework; and transition metal oxides including iron oxide and cobalt oxide, which react with lithium ions via an unusual conversion reaction. For all three systems, we will emphasize that creating nanomaterials with unique structures could effectively improve the lithium storage properties of these metal oxides. We will also highlight that the lithium storage capability can be further enhanced through designing advanced nanocomposite materials containing metal oxides and other carbonaceous supports. By providing such a rather systematic survey, we aim to stress the importance of proper nanostructuring and advanced compositing that would result in improved physicochemical properties of metal oxides, thus making them promising negative electrodes for next-generation LIBs.

  16. Advanced theory of driven birdcage resonator with losses for biomedical magnetic resonance imaging and spectroscopy.

    PubMed

    Novikov, Alexander

    2011-02-01

    A complete time-dependent physics theory of symmetric unperturbed driven hybrid birdcage resonator was developed for general application. In particular, the theory can be applied for radiofrequency (RF) coil engineering, computer simulations of coil-sample interaction, etc. Explicit time dependence is evaluated for different forms of driving voltage. The major steps of the solution development are shown and appropriate explanations are given. Green's functions and spectral density formula were developed for any form of periodic driving voltage. The concept of distributed power losses based on transmission line theory is developed for evaluation of local losses of a coil. Three major types of power losses are estimated as equivalent series resistances in the circuit of the birdcage resonator. Values of generated resistances in legs and end-rings are estimated. An application of the theory is shown for many practical cases. Experimental curve of B(1) field polarization dependence is measured for eight-sections birdcage coil. It was shown that the steady-state driven resonance frequencies do not depend on damping factor unlike the free oscillation (transient) frequencies. An equivalent active resistance is generated due to interaction of RF electromagnetic field with a sample. Resistance of the conductor (enhanced by skin effect), Eddy currents and dielectric losses are the major types of losses which contribute to the values of generated resistances. A biomedical sample for magnetic resonance imaging and spectroscopy is the source of the both Eddy current and dielectric losses of a coil. As demonstrated by the theory, Eddy current loss is the major effect of coil shielding.

  17. Advanced Theory of Driven Birdcage Resonator with Losses for Biomedical Magnetic Resonance Imaging and Spectroscopy

    PubMed Central

    Novikov, Alexander

    2010-01-01

    A complete time-dependent physics theory of symmetric unperturbed driven Hybrid Birdcage resonator was developed for general application. In particular, the theory can be applied for RF coil engineering, computer simulations of coil-sample interaction, etc. Explicit time dependence is evaluated for different forms of driving voltage. The major steps of the solution development are shown and appropriate explanations are given. Green’s functions and spectral density formula were developed for any form of periodic driving voltage. The concept of distributed power losses based on transmission line theory is developed for evaluation of local losses of a coil. Three major types of power losses are estimated as equivalent series resistances in the circuit of the Birdcage resonator. Values of generated resistances in Legs and End-Rings are estimated. An application of the theory is shown for many practical cases. Experimental curve of B1 field polarization dependence is measured for eight-sections Birdcage coil. It was shown, that the steady-state driven resonance frequencies do not depend on damping factor unlike the free oscillation (transient) frequencies. An equivalent active resistance is generated due to interaction of RF electromagnetic field with a sample. Resistance of the conductor (enhanced by skin effect), Eddy currents and dielectric losses are the major types of losses which contribute to the values of generated resistances. A biomedical sample for magnetic resonance imaging and spectroscopy is the source of the both Eddy current and dielectric losses of a coil. As demonstrated by the theory, Eddy currents losses is the major effect of coil shielding. PMID:20869184

  18. ADX: A high Power Density, Advanced RF-Driven Divertor Test Tokamak for PMI studies

    NASA Astrophysics Data System (ADS)

    Whyte, Dennis; ADX Team

    2015-11-01

    The MIT PSFC and collaborators are proposing an advanced divertor experiment, ADX; a divertor test tokamak dedicated to address critical gaps in plasma-material interactions (PMI) science, and the world fusion research program, on the pathway to FNSF/DEMO. Basic ADX design features are motivated and discussed. In order to assess the widest range of advanced divertor concepts, a large fraction (>50%) of the toroidal field volume is purpose-built with innovative magnetic topology control and flexibility for assessing different surfaces, including liquids. ADX features high B-field (>6 Tesla) and high global power density (P/S ~ 1.5 MW/m2) in order to access the full range of parallel heat flux and divertor plasma pressures foreseen for reactors, while simultaneously assessing the effect of highly dissipative divertors on core plasma/pedestal. Various options for efficiently achieving high field are being assessed including the use of Alcator technology (cryogenic cooled copper) and high-temperature superconductors. The experimental platform would also explore advanced lower hybrid current drive and ion-cyclotron range of frequency actuators located at the high-field side; a location which is predicted to greatly reduce the PMI effects on the launcher while minimally perturbing the core plasma. The synergistic effects of high-field launchers with high total B on current and flow drive can thus be studied in reactor-relevant boundary plasmas.

  19. Electrochemically driven biocatalysis of the oxygenase domain of neuronal nitric oxide synthase in indium tin oxide nanoparticles/polyvinyl alcohol nanocomposite.

    PubMed

    Xu, Xuan; Wollenberger, Ulla; Qian, Jing; Lettau, Katrin; Jung, Christiane; Liu, Songqin

    2013-12-01

    Nitric oxide synthase (NOS) plays a critical role in a number of key physiological and pathological processes. Investigation of electron-transfer reactions in NOS would contribute to a better understanding of the nitric oxide (NO) synthesis mechanism. Herein, we describe an electrochemically driven catalytic strategy, using a nanocomposite that consisted of the oxygenase domain of neuronal NOS (D290nNOSoxy), indium tin oxide (ITO) nanoparticles and polyvinyl alcohol (PVA). Fast direct electron transfer between electrodes and D290nNOSoxy was observed with the heterogeneous electron transfer rate constant (ket) of 154.8 ± 0.1s(-1) at the scan rate of 5 Vs(-1). Moreover, the substrate N(ω)-hydroxy-L-arginine (NHA) was used to prove the concept of electrochemically driven biocatalysis of D290nNOSoxy. In the presence of the oxygen cosubstrate and tetrahydrobiopterin (BH4) cofactor, the addition of NHA caused the decreases of both oxidation current at +0.1 V and reduction current at potentials ranging from -0.149 V to -0.549 V vs Ag/AgCl. Thereafter, a series of control experiments such as in the absence of BH4 or D290nNOSoxy were performed. All the results demonstrated that D290nNOSoxy biocatalysis was successfully driven by electrodes in the presence of BH4 and oxygen. This novel bioelectronic system showed potential for further investigation of NOS and biosensor applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. High sensitivity far infrared laser diagnostics for the C-2U advanced beam-driven field-reversed configuration plasmas

    SciTech Connect

    Deng, B. H. Beall, M.; Schroeder, J.; Settles, G.; Feng, P.; Kinley, J. S.; Gota, H.; Thompson, M. C.

    2016-11-15

    A high sensitivity multi-channel far infrared laser diagnostics with switchable interferometry and polarimetry operation modes for the advanced neutral beam-driven C-2U field-reversed configuration (FRC) plasmas is described. The interferometer achieved superior resolution of 1 × 10{sup 16} m{sup −2} at >1.5 MHz bandwidth, illustrated by measurement of small amplitude high frequency fluctuations. The polarimetry achieved 0.04° instrument resolution and 0.1° actual resolution in the challenging high density gradient environment with >0.5 MHz bandwidth, making it suitable for weak internal magnetic field measurements in the C-2U plasmas, where the maximum Faraday rotation angle is less than 1°. The polarimetry resolution data is analyzed, and high resolution Faraday rotation data in C-2U is presented together with direct evidences of field reversal in FRC magnetic structure obtained for the first time by a non-perturbative method.

  1. Planned High-gradient Flat-beam-driven Dielectric Wakefield Experiments at the Fermilab’s Advanced Superconducting Test Accelerator

    SciTech Connect

    Lemery, Francois; Mihalcea, Daniel; Piot, Philippe; Zhu, Jun

    2014-07-01

    In beam driven dielectric wakefield acceleration (DWA), high-gradient short-wavelength accelerating fields are generally achieved by employing dielectric-lined waveguides (DLWs)  with small aperture which constraints the beam sizes. In this paper we investigate the possibility of using a low-energy (50-MeV) flat beams to induce high-gradient wakes in a slab-symmetric DLW. We demonstrate via numerical simulations the possibility to produce axial electric field with peak amplitude close to 0.5 GV/m. Our studies are carried out using the Fermilab's Advanced Superconducting Test Accelerator (ASTA) photoinjector beamline. We finally discuss a possible experiment that could be performed in the ASTA photoinjector and eventually at higher energies.  

  2. High sensitivity far infrared laser diagnostics for the C-2U advanced beam-driven field-reversed configuration plasmas.

    PubMed

    Deng, B H; Beall, M; Schroeder, J; Settles, G; Feng, P; Kinley, J S; Gota, H; Thompson, M C

    2016-11-01

    A high sensitivity multi-channel far infrared laser diagnostics with switchable interferometry and polarimetry operation modes for the advanced neutral beam-driven C-2U field-reversed configuration (FRC) plasmas is described. The interferometer achieved superior resolution of 1 × 10(16) m(-2) at >1.5 MHz bandwidth, illustrated by measurement of small amplitude high frequency fluctuations. The polarimetry achieved 0.04° instrument resolution and 0.1° actual resolution in the challenging high density gradient environment with >0.5 MHz bandwidth, making it suitable for weak internal magnetic field measurements in the C-2U plasmas, where the maximum Faraday rotation angle is less than 1°. The polarimetry resolution data is analyzed, and high resolution Faraday rotation data in C-2U is presented together with direct evidences of field reversal in FRC magnetic structure obtained for the first time by a non-perturbative method.

  3. Polyethylene Oxidation in Total Hip Arthroplasty: Evolution and New Advances

    PubMed Central

    Gómez-Barrena, Enrique; Medel, Francisco; Puértolas, José Antonio

    2009-01-01

    Ultra-high molecular weight polyethylene (UHMWPE) remains the gold standard acetabular bearing material for hip arthroplasty. Its successful performance has shown consistent results and survivorship in total hip replacement (THR) above 85% after 15 years, with different patients, surgeons, or designs. As THR results have been challenged by wear, oxidation, and liner fracture, relevant research on the material properties in the past decade has led to the development and clinical introduction of highly crosslinked polyethylenes (HXLPE). More stress on the bearing (more active, overweighted, younger patients), and more variability in the implantation technique in different small and large Hospitals may further compromise the clinical performance for many patients. The long-term in vivo performance of these materials remains to be proven. Clinical and retrieval studies after more than 5 years of in vivo use with HXLPE in THR are reviewed and consistently show a substantial decrease in wear rate. Moreover, a second generation of improved polyethylenes is backed by in vitro data and awaits more clinical experience to confirm the experimental improvements. Also, new antioxidant, free radical scavengers, candidates and the reinforcement of polyethylene through composites are currently under basic research. Oxidation of polyethylene is today significantly reduced by present formulations, and this forgiving, affordable, and wellknown material is still reliable to meet today’s higher requirements in total hip replacement. PMID:20111694

  4. Simulation of fast-ion-driven Alfvén eigenmodes on the Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Hu, Youjun; Todo, Y.; Pei, Youbin; Li, Guoqiang; Qian, Jinping; Xiang, Nong; Zhou, Deng; Ren, Qilong; Huang, Juan; Xu, Liqing

    2016-02-01

    Kinetic-MHD hybrid simulations are carried out to investigate possible fast-ion-driven modes on the Experimental Advanced Superconducting Tokamak. Three typical kinds of fast-ion-driven modes, namely, toroidicity-induced Alfvén eigenmodes, reversed shear Alfvén eigenmodes, and energetic-particle continuum modes, are observed simultaneously in the simulations. The simulation results are compared with the results of an ideal MHD eigenvalue code, which shows agreement with respect to the mode frequency, dominant poloidal mode numbers, and radial location. However, the modes in the hybrid simulations take a twisted structure on the poloidal plane, which is different from the results of the ideal MHD eigenvalue code. The twist is due to the radial phase variation of the eigenfunction, which may be attributed to the non-perturbative kinetic effects of the fast ions. By varying the stored energy of fast ions to change the fast ion drive in the simulations, it is demonstrated that the twist (i.e., the radial phase variation) is positively correlated with the fast ion drive.

  5. Dinitrogenase-Driven Photobiological Hydrogen Production Combats Oxidative Stress in Cyanothece sp. Strain ATCC 51142

    SciTech Connect

    Sadler, Natalie C.; Bernstein, Hans C.; Melnicki, Matthew R.; Charania, Moiz A.; Hill, Eric A.; Anderson, Lindsey N.; Monroe, Matthew E.; Smith, Richard D.; Beliaev, Alexander S.; Wright, Aaron T.; Nojiri, H.

    2016-10-14

    ABSTRACT

    Photobiologically synthesized hydrogen (H2) gas is carbon neutral to produce and clean to combust, making it an ideal biofuel.Cyanothecesp. strain ATCC 51142 is a cyanobacterium capable of performing simultaneous oxygenic photosynthesis and H2production, a highly perplexing phenomenon because H2evolving enzymes are O2sensitive. We employed a system-levelin vivochemoproteomic profiling approach to explore the cellular dynamics of protein thiol redox and how thiol redox mediates the function of the dinitrogenase NifHDK, an enzyme complex capable of aerobic hydrogenase activity. We found that NifHDK responds to intracellular redox conditions and may act as an emergency electron valve to prevent harmful reactive oxygen species formation in concert with other cell strategies for maintaining redox homeostasis. These results provide new insight into cellular redox dynamics useful for advancing photolytic bioenergy technology and reveal a new understanding for the biological function of NifHDK.

    IMPORTANCEHere, we demonstrate that high levels of hydrogen synthesis can be induced as a protection mechanism against oxidative stress via the dinitrogenase enzyme complex inCyanothecesp. strain ATCC 51142. This is a previously unknown feature of cyanobacterial dinitrogenase, and we anticipate that it may represent a strategy to exploit cyanobacteria for efficient and scalable hydrogen production. We utilized a chemoproteomic approach to capture thein situdynamics of reductant partitioning within the cell, revealing proteins and reactive thiols that may be involved in redox sensing and signaling. Additionally, this method is widely applicable across biological systems to achieve a greater understanding of how cells navigate their environment

  6. Photovoltaic-driven organic electrosynthesis and efforts toward more sustainable oxidation reactions

    PubMed Central

    Nguyen, Bichlien H; Perkins, Robert J; Smith, Jake A

    2015-01-01

    Summary The combination of visible light, photovoltaics, and electrochemistry provides a convenient, inexpensive platform for conducting a wide variety of sustainable oxidation reactions. The approach presented in this article is compatible with both direct and indirect oxidation reactions, avoids the need for a stoichiometric oxidant, and leads to hydrogen gas as the only byproduct from the corresponding reduction reaction. PMID:25815081

  7. Tertiary treatment of a municipal wastewater toward pharmaceuticals removal by chemical and electrochemical advanced oxidation processes.

    PubMed

    Moreira, Francisca C; Soler, J; Alpendurada, M F; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

    2016-11-15

    This study focuses on the degradation of pharmaceuticals from a municipal wastewater after secondary treatment by applying various advanced oxidation processes (AOPs) and electrochemical AOPs (EAOPs) like UVC, H2O2/UVC, anodic oxidation (AO), AO with electrogenerated H2O2 (AO-H2O2), AO-H2O2/UVC and photoelectro-Fenton (PEF) using either UVC radiation (PEF-UVC) or UVA radiation (PEF-UVA). The municipal wastewater after secondary treatment was spiked with 5.0 mg L(-1) of trimethoprim (TMP) antibiotic. The efficiency of processes to remove TMP followed the order UVC < AO-H2O2 < PEF-UVA < AO ≈ PEF-UVC < AO-H2O2/UVC < PEF-UVA (pH = 2.8) < H2O2/UVC ≈ PEF-UVC (pH = 2.8), using neutral pH, except when identified. While the UVC radiation alone led to a very low TMP removal, the H2O2/UVC process promoted a very high TMP degradation due to the production of hydroxyl radicals (OH) by H2O2 cleavage. In the AO-H2O2/UVC process, the electrogeneration of H2O2 can avoid the risks associated with the transportation, storage and manipulation of this oxidant and, furthermore, OH at the anode surface are also formed. Nevertheless, low contents of H2O2 were detected mainly at the beginning of the reaction, leading to a lower initial reaction rate when compared with the H2O2/UVC system. In the PEF-UVC, the addition of iron at neutral pH led to the visible formation of insoluble iron oxides that can filter the light. At pH 2.8, the iron remained dissolved, thereby promoting the Fenton's reaction and increasing the organics removal. The UVA-driven processes showed limited efficiency when compared with those using UVC light. For all processes with H2O2 electrogeneration, the active chlorine species can be scavenged by the H2O2, diminishing the efficiency of the processes. This can explain the lower efficiency of AO-H2O2 when compared with AO. Moreover, the degradation of the MWWTP effluent spiked with 18 pharmaceuticals in μg L(-1) during AO process was assessed

  8. Effects of temperature and acidic pre-treatment on Fenton-driven oxidation of MTBE-spent granular activated carbon

    SciTech Connect

    Kan, E.; Huling, S.G.

    2009-03-01

    The effects of temperature and acidic pretreatment on Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC, derived from bituminous coal) were investigated. Limiting factors in MTBE removal in GAC include the heterogeneous distribution of amended Fe, and slow intraparticle diffusive transport of MTBE and hydrogen peroxide (H{sub 2}O{sub 2}) into the 'reactive zone'. Acid pretreatment of GAC before Fe amendment altered the surface chemistry of the GAC, lowered the pH point of zero charge, and resulted in greater penetration and more uniform distribution of Fe in GAC. This led to a condition where Fe, MTBE, and H{sub 2}O{sub 2} coexisted over a larger volume of the GAC contributing to greater MTBE oxidation and removal. H{sub 2}O{sub 2} reaction and MTBE removal in GAC increased with temperature. Modeling H{sub 2}O{sub 2} transport and reaction in GAC indicated that H{sub 2}O{sub 2} penetration was inversely proportional with temperature and tortuosity, and occurred over a larger fraction of the total volume of small GAC particles (0.3 mm diameter) relative to large particles (1.2 mm diameter). Acidic pretreatment of GAC, Fe-amendment, elevated reaction temperature, and use of small GAC particles are operational parameters that improve Fenton-driven oxidation of MTBE in GAC. 29 refs., 6 figs., 1 tab.

  9. Recent Advances in VisIt: AMR Streamlines and Query-Driven Visualization

    SciTech Connect

    Weber, Gunther; Ahern, Sean; Bethel, Wes; Borovikov, Sergey; Childs, Hank; Deines, Eduard; Garth, Christoph; Hagen, Hans; Hamann, Bernd; Joy, Kenneth; Martin, David; Meredith, Jeremy; Prabhat,; Pugmire, David; Rubel, Oliver; Van Straalen, Brian; Wu, Kesheng

    2009-11-12

    Adaptive Mesh Refinement (AMR) is a highly effective method for simulations spanning a large range of spatiotemporal scales such as those encountered in astrophysical simulations. Combining research in novel AMR visualization algorithms and basic infrastructure work, the Department of Energy's (DOEs) Science Discovery through Advanced Computing (SciDAC) Visualization and Analytics Center for Enabling Technologies (VACET) has extended VisIt, an open source visualization tool that can handle AMR data without converting it to alternate representations. This paper focuses on two recent advances in the development of VisIt. First, we have developed streamline computation methods that properly handle multi-domain data sets and utilize effectively multiple processors on parallel machines. Furthermore, we are working on streamline calculation methods that consider an AMR hierarchy and detect transitions from a lower resolution patch into a finer patch and improve interpolation at level boundaries. Second, we focus on visualization of large-scale particle data sets. By integrating the DOE Scientific Data Management (SDM) Center's FastBit indexing technology into VisIt, we are able to reduce particle counts effectively by thresholding and by loading only those particles from disk that satisfy the thresholding criteria. Furthermore, using FastBit it becomes possible to compute parallel coordinate views efficiently, thus facilitating interactive data exploration of massive particle data sets.

  10. A Multi-layer, Data-driven Advanced Reasoning Tool for Intelligent Data Mining and Analysis for Smart Grids

    SciTech Connect

    Lu, Ning; Du, Pengwei; Greitzer, Frank L.; Guo, Xinxin; Hohimer, Ryan E.; Pomiak, Yekaterina G.

    2012-12-31

    This paper presents the multi-layer, data-driven advanced reasoning tool (M-DART), a proof-of-principle decision support tool for improved power system operation. M-DART will cross-correlate and examine different data sources to assess anomalies, infer root causes, and anneal data into actionable information. By performing higher-level reasoning “triage” of diverse data sources, M-DART focuses on early detection of emerging power system events and identifies highest priority actions for the human decision maker. M-DART represents a significant advancement over today’s grid monitoring technologies that apply offline analyses to derive model-based guidelines for online real-time operations and use isolated data processing mechanisms focusing on individual data domains. The development of the M-DART will bridge these gaps by reasoning about results obtained from multiple data sources that are enabled by the smart grid infrastructure. This hybrid approach integrates a knowledge base that is trained offline but tuned online to capture model-based relationships while revealing complex causal relationships among data from different domains.

  11. Dietary advanced lipid oxidation endproducts are risk factors to human health.

    PubMed

    Kanner, Joseph

    2007-09-01

    Lipid oxidation in foods is one of the major degradative processes responsible for losses in food quality. The oxidation of unsaturated fatty acids results in significant generation of dietary advanced lipid oxidation endproducts (ALEs) which are in part cytotoxic and genotoxic compounds. The gastrointestinal tract is constantly exposed to dietary oxidized food compounds, after digestion a part of them are absorbed into the lymph or directly into the blood stream. After ingestion of oxidized fats animals and human have been shown to excrete in urine increase amounts of malondialdehyde but also lipophilic carbonyl compounds. Oxidized cholesterol in the diet was found to be a source of oxidized lipoproteins in human serum. Some of the dietary ALEs, which are absorbed from the gut to the circulatory system, seems to act as injurious chemicals that activate an inflammatory response which affects not only circulatory system but also organs such as liver, kidney, lung, and the gut itself. We believe that repeated consumption of oxidized fat in the diet poses a chronic threat to human health. High concentration of dietary antioxidants could prevent lipid oxidation and ALEs generation not only in foods but also in stomach condition and thereby potentially decrease absorption of ALEs from the gut. This could explains the health benefit of diets containing large amounts of dietary antioxidants such those present in fruits and vegetables, or products such as red-wine or tea consuming during the meal.

  12. Advanced scheme for high-yield laser driven proton-boron fusion reaction

    NASA Astrophysics Data System (ADS)

    Margarone, D.; Picciotto, A.; Velyhan, A.; Krasa, J.; Kucharik, M.; Morrissey, M.; Mangione, A.; Szydlowsky, A.; Malinowska, A.; Bertuccio, G.; Shi, Y.; Crivellari, M.; Ullschmied, J.; Bellutti, P.; Korn, G.

    2015-02-01

    A low contrast nanosecond laser pulse with relatively low intensity (3 × 1016 W cm-2) was used to enhance the yield of induced nuclear reactions in advanced solid targets. In particular the "ultraclean" proton-boron fusion reaction, producing energetic alpha-particles without neutron generation, was chosen. A spatially well-defined layer of boron dopants in a hydrogen-enriched silicon substrate was used as target. The combination of the specific target geometry and the laser pulse temporal shape allowed enhancing the yield of alpha-particles up to 109 per steradian, i.e 100 times higher than previous experimental achievements. Moreover the alpha particle stream presented a clearly peaked angular and energy distribution, which make this secondary source attractive for potential applications. This result can be ascribed to the interaction of the long laser pre-pulse with the target and to the optimal target geometry and composition.

  13. Power, resolution and bias: recent advances in insect phylogeny driven by the genomic revolution.

    PubMed

    Yeates, David K; Meusemann, Karen; Trautwein, Michelle; Wiegmann, Brian; Zwick, Andreas

    2016-02-01

    Our understanding on the phylogenetic relationships of insects has been revolutionised in the last decade by the proliferation of next generation sequencing technologies (NGS). NGS has allowed insect systematists to assemble very large molecular datasets that include both model and non-model organisms. Such datasets often include a large proportion of the total number of protein coding sequences available for phylogenetic comparison. We review some early entomological phylogenomic studies that employ a range of different data sampling protocols and analyses strategies, illustrating a fundamental renaissance in our understanding of insect evolution all driven by the genomic revolution. The analysis of phylogenomic datasets is challenging because of their size and complexity, and it is obvious that the increasing size alone does not ensure that phylogenetic signal overcomes systematic biases in the data. Biases can be due to various factors such as the method of data generation and assembly, or intrinsic biological feature of the data per se, such as similarities due to saturation or compositional heterogeneity. Such biases often cause violations in the underlying assumptions of phylogenetic models. We review some of the bioinformatics tools available and being developed to detect and minimise systematic biases in phylogenomic datasets. Phylogenomic-scale data coupled with sophisticated analyses will revolutionise our understanding of insect functional genomics. This will illuminate the relationship between the vast range of insect phenotypic diversity and underlying genetic diversity. In combination with rapidly developing methods to estimate divergence times, these analyses will also provide a compelling view of the rates and patterns of lineagenesis (birth of lineages) over the half billion years of insect evolution.

  14. An advanced protocol-driven transition from parenteral prostanoids to inhaled trepostinil in pulmonary arterial hypertension

    PubMed Central

    Agarwal, Manyoo; Rischard, Franz; De Marco, Teresa

    2016-01-01

    Abstract Patients with pulmonary arterial hypertension (PAH) often require parenteral prostanoids to improve symptoms and signs of PAH. Complications of parenteral prostanoids—such as catheter-related infections and intolerable adverse effects—may develop, prompting transition to inhaled prostanoids. We report a prospective, protocol-driven transition from parenteral prostanoids to inhaled prostanoids with monitoring of exercise gas exchange and acute hemodynamics. Three PAH centers recruited patients transitioning from parenteral prostanoids to inhaled trepostinil. Rigid inclusion criteria were used, including parenteral prostanoid dose < 30 ng/kg/min, New York Heart Association functional class (FC) < 3, and pulmonary vascular resistance (PVR) < 6 Wood units. Of the 9 patients meeting initial inclusion criteria, 3 were excluded. In the remaining patients, the parenteral prostanoid was reduced and the inhaled prostanoid was increased over 24–36 hours with continuous hemodynamic monitoring. Exercise capacity and FC were measured at baseline and weeks 1, 4, and 12. All patients were successfully weaned from parenteral prostanoids. An acute PVR decrease was seen with most inhaled prostanoid doses, but PVR varied throughout the transition. Patients tolerated inhaled prostanoids for 9–12 breaths 4 times a day with no treatment-limiting adverse events. At week 12, FC was unchanged, and all patients continued to receive inhaled prostanoids without serious adverse events or additional PAH therapy. In 5 of 6 patients, 6-minute walk distance and peak V˙O2 were within 10% of baseline. Using a strict transition protocol and rigid patient selection criteria, the parenteral prostanoid to inhaled prostanoid transition appeared safe and well tolerated and did not result in clinical deterioration over 12 weeks. Hemodynamic variability noted acutely during transition in our study did not adversely affect successful transition. (Trial registration: Clinical

  15. DEMONSTRATION OF THE HIPOX ADVANCED OXIDATION TECHNOLOGY FOR THE TREATMENT OF MTBE-CONTAMINATED GROUNDWATER

    EPA Science Inventory

    The HiPOx technology is an advanced oxidation process that incorporates high-precision delivery of ozone and hydrogen peroxide to chemically destroy organic contaminants with the promise of minimizing bromate formation. A MTBE-contaminated groundwater from the Ventura County Nav...

  16. Development of Advanced Oxide Dispersion Strengthened Tungsten Heavy Alloy for Penetrator Application

    DTIC Science & Technology

    2005-09-30

    preparation, sintering, cyclic heat-treatment, swaging , and annealing processes, on microstructures and static/dynamic mechanical properties of ODS tungsten ... tungsten / tungsten contiguity. The swaging and annealing processes of ODS tungsten heavy alloy increase the tensile strength with decreasing the...Final Report for 2nd Year Contract of AOARD 034032 Development of Advanced Oxide Dispersion Strengthened Tungsten Heavy Alloy for

  17. TiO2-Based Advanced Oxidation Nanotechnologies For Water Purification And Reuse

    EPA Science Inventory

    TiO2 photocatalysis, one of the UV-based advanced oxidation technologies (AOTs) and nanotechnologies (AONs), has attracted great attention for the development of efficient water treatment and purification systems due to the effectiveness of TiO2 to generate ...

  18. TiO2-Based Advanced Oxidation Nanotechnologies For Water Purification And Reuse

    EPA Science Inventory

    TiO2 photocatalysis, one of the UV-based advanced oxidation technologies (AOTs) and nanotechnologies (AONs), has attracted great attention for the development of efficient water treatment and purification systems due to the effectiveness of TiO2 to generate ...

  19. DESTRUCTION OF PAHS AND PCBS IN WATER USING SULFATE RADICAL-BASED CATALYTIC ADVANCED OXIDATION PROCESSES

    EPA Science Inventory

    A new class of advanced oxidation processes (AOPs) based on sulfate radicals is being tested for the degradation of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in aqueous solution. These AOPs are based on the generation of sulfate radicals through...

  20. DEMONSTRATION OF THE HIPOX ADVANCED OXIDATION TECHNOLOGY FOR THE TREATMENT OF MTBE-CONTAMINATED GROUNDWATER

    EPA Science Inventory

    The HiPOx technology is an advanced oxidation process that incorporates high-precision delivery of ozone and hydrogen peroxide to chemically destroy organic contaminants with the promise of minimizing bromate formation. A MTBE-contaminated groundwater from the Ventura County Nav...

  1. A comparison of single oxidants versus advanced oxidation processes as chlorine-alternatives for wild blueberry processing (Vaccinium angustifolium).

    PubMed

    Crowe, Kristi M; Bushway, Alfred A; Bushway, Rodney J; Davis-Dentici, Katherine; Hazen, Russell A

    2007-05-01

    Advanced oxidation processes and single chemical oxidants were evaluated for their antimicrobial efficacy against common spoilage bacteria isolated from lowbush blueberries. Predominant bacterial flora were identified using biochemical testing with the assessment of relative abundance using non-selective and differential media. Single chemical oxidants evaluated for postharvest processing of lowbush blueberries included 1% hydrogen peroxide, 100 ppm chlorine, and 1 ppm aqueous ozone while advanced oxidation processes (AOPs) included combinations of 1% hydrogen peroxide/UV, 100 ppm chlorine/UV, and 1 ppm ozone/1% hydrogen peroxide/UV. Enterobacter agglomerans and Pseudomonas fluorescens were found to comprise 90-95% of the bacterial flora on lowbush blueberries. Results of inoculation studies reveal significant log reductions (p< or 5) in populations of E. agglomerans and P. fluorescens on all samples receiving treatment with 1% hydrogen peroxide, 1% hydrogen peroxide/UV, 1 ppm ozone, or a combined ozone/hydrogen peroxide/UV treatment as compared to chlorine treatments and unwashed control berries. Although population reductions approached 2.5 log CFU/g, microbial reductions among these treatments were not found to be significantly different (p< or 5) from each other despite the synergistic potential that should result from AOPs; furthermore, as a single oxidant, UV inactivation of inoculated bacteria was minimal and did not prove effective as a non-aqueous bactericidal process for fresh pack blueberries. Overall, results indicate that hydrogen peroxide and ozone, as single chemical oxidants, are as effective as AOPs and could be considered as chlorine-alternatives in improving the microbiological quality of lowbush blueberries.

  2. Differential oxidative status and immune characterization of the early and advanced stages of human breast cancer.

    PubMed

    Panis, C; Victorino, V J; Herrera, A C S A; Freitas, L F; De Rossi, T; Campos, F C; Simão, A N Colado; Barbosa, D S; Pinge-Filho, P; Cecchini, R; Cecchini, A L

    2012-06-01

    Breast cancer is the malignant neoplasia with the highest incidence in women worldwide. Chronic oxidative stress and inflammation have been indicated as major mediators during carcinogenesis and cancer progression. Human studies have not considered the complexity of tumor biology during the stages of cancer advance, limiting their clinical application. The purpose of this study was to characterize systemic oxidative stress and immune response parameters in early (ED; TNM I and II) and advanced disease (AD; TNM III and IV) of patients diagnosed with infiltrative ductal carcinoma breast cancer. Oxidative stress parameters were evaluated by plasmatic lipoperoxidation, carbonyl content, thiobarbituric reactive substances (TBARS), nitric oxide levels (NO), total radical antioxidant parameter (TRAP), superoxide dismutase, and catalase activities and GSH levels. Immune evaluation was determined by TNF-α, IL-1β, IL-12, and IL-10 levels and leukocytes oxidative burst evaluation by chemiluminescence. Tissue damage analysis included heart (total CK and CKMB), liver (AST, ALT, GGT), and renal (creatinine, urea, and uric acid) plasmatic markers. C-reactive protein (CRP) and iron metabolism were also evaluated. Analysis of the results verified different oxidative stress statuses occur at distinct cancer stages. ED was characterized by reduction in catalase, 8-isoprostanes, and GSH levels, with enhanced lipid peroxidation and TBARS levels. AD exhibited more pronounced oxidative status, with reduction in catalase activity and TRAP, intense lipid peroxidation and high levels of NO, TBARs, and carbonyl content. ED patients presented a Th2 immune pattern, while AD exhibited Th1 status. CRP levels and ferritin were increased in both stages of disease. Leukocytes burst impairment was observed in both the groups. Plasma iron levels were significantly elevated in AD. The data obtained indicated that oxidative stress enhancement and immune response impairment may be necessary to ensure

  3. Early experience with digital advance care planning and directives, a novel consumer-driven program

    PubMed Central

    Yang, Zhiyong; Spivey, Christy; Boardman, Bonnie; Courtney, Maureen

    2016-01-01

    Barriers to traditional advance care planning (ACP) and advance directive (AD) creation have limited the promise of ACP/AD for individuals and families, the healthcare team, and society. Our objectives were to determine the results of a digital ACP/AD through which consumers create, store, locate, and retrieve their ACP/AD at no charge and with minimal physician involvement, and the ACP/AD can be integrated into the electronic health record. The authors chose 900 users of MyDirectives, a digital ACP/AD tool, to achieve proportional representation of all 50 states by population size and then reviewed their responses. The 900 participants had an average age of 50.8 years (SD = 16.6); 84% of the men and 91% of the women were in self-reported good health when signing their ADs. Among the respondents, 94% wanted their physicians to consult a supportive and palliative care team if they were seriously ill; nearly 85% preferred cessation of life-sustaining treatments during their final days; 76% preferred to spend their final days at home or in a hospice; and 70% would accept attempted cardiopulmonary resuscitation in limited circumstances. Most respondents wanted an autopsy under certain conditions, and 62% wished to donate their organs. In conclusion, analysis of early experience with this ACP/AD platform demonstrates that individuals of different ages and conditions can engage in an interrogatory process about values, develop ADs that are more nuanced than traditional paper-based ADs in reflecting those values, and easily make changes to their ADs. Online ADs have the potential to remove barriers to ACP/AD and thus further improve patient-centered end-of-life care. PMID:27365867

  4. Advances in Understanding the Actions of Nitrous Oxide

    PubMed Central

    Emmanouil, Dimitris E; Quock, Raymond M

    2007-01-01

    Nitrous oxide (N2O) has been used for well over 150 years in clinical dentistry for its analgesic and anxiolytic properties. This small and simple inorganic chemical molecule has indisputable effects of analgesia, anxiolysis, and anesthesia that are of great clinical interest. Recent studies have helped to clarify the analgesic mechanisms of N2O, but the mechanisms involved in its anxiolytic and anesthetic actions remain less clear. Findings to date indicate that the analgesic effect of N2O is opioid in nature, and, like morphine, may involve a myriad of neuromodulators in the spinal cord. The anxiolytic effect of N2O, on the other hand, resembles that of benzodiazepines and may be initiated at selected subunits of the γ-aminobutyric acid type A (GABAA) receptor. Similarly, the anesthetic effect of N2O may involve actions at GABAA receptors and possibly at N-methyl-D-aspartate receptors as well. This article reviews the latest information on the proposed modes of action for these clinicaleffects of N2O. PMID:17352529

  5. Advanced oxidation for the treatment of chlorpyrifos in aqueous solution.

    PubMed

    Ismail, M; Khan, Hasan M; Sayed, Murtaza; Cooper, William J

    2013-10-01

    Chlorpyrifos is an organophosphate pesticide and is significant because of its extensive use, persistence in the environment, wide distribution, and its toxicity may lead to lung and central nervous system damage, developmental and autoimmune disorders and vomiting. In the present study, the irradiation of chlorpyrifos in aqueous solution by (60)Co γ-rays was conducted on a laboratory scale and the removal efficiency of chlorpyrifos was investigated. The SPME-GC-ECD method was used for analysis of chlorpyrifos. Aqueous solutions of different concentrations of target compound (200-1000 μg L(-1)) were irradiated through 30-575 Gy. Gamma irradiation showed 100% degradation for a 500 μg L(-1) solution at an absorbed dose of 575 Gy (the dose rate was 300 Gy h(-1)). The radiolysis of chlorpyrifos was pseudo-first order (decay) with respect to dose. The dose constants determined in this study ranged from 8.2×10(-3) to 2.6×10(-2) Gy(-1), and decreased with an increase in the initial concentration of chlorpyrifos, while the radiation chemical yield (G-value) for the loss of chlorpyrifos was found to decrease with increasing absorbed dose. The effect of saturated solutions of N2 and N2O, and radical scavengers tert-butanol, iso-propanol, H2O2, NaNO3 and NaNO2 on the degradation of chlorpyrifos were also studied. The results showed that the oxidative OH was the most important in the degradation of chlorpyrifos, while the reductive radicals, aqueous electron and H, were of less importance for the degradation of chlorpyrifos. The inorganic by-products Cl(-), SO4(2-) and PO4(3-) were quantitatively determined by IC.

  6. Advanced alternate planar geometry solid oxide fuel cells. Final report

    SciTech Connect

    Elangovan, S.; Prouse, D.; Khandkar, A.; Donelson, R.; Marianowski, L.

    1992-11-01

    The potential of high temperature Solid Oxide Fuel Cells as high performance, high efficiency energy conversion device is well known. Investigation of several cell designs have been undertaken by various researchers to derive the maximum performance benefit from the device while maintaining a lower cost of production to meet the commercialization cost target. The present investigation focused on the planar SOFC design which allows for the use of mature low cost production processes to be employed. A novel design concept was investigated which allows for improvements in performance through increased interface stability, and lowering of cost through enhanced structural integrity and the use of low cost metal interconnects. The new cell design consisted of a co-sintered porous/dense/porous zirconia layer with the electrode material infiltrated into the porous layers. The two year program conducted by a team involving Ceramatec and the Institute of Gas Technology, culminated in a multi-cell stack test that exhibited high performance. Considerable progress was achieved in the selection of cell components, and establishing and optimizing the cell and stack fabrication parameters. It was shown that the stack components exhibited high conductivities and low creep at the operating temperature. The inter-cell resistive losses were shown to be small through out-of-cell characterization. The source of performance loss was identified to be the anode electrolyte interface. This loss however can be minimized by improving the anode infiltration technique. Manifolding and sealing of the planar devices posed considerable challenge. Even though the open circuit voltage was 250 mV/cell lower than theoretical, the two cell stack had a performance of 300 mA/cm{sup 2} at 0.4V/cell with an area specific resistance of 1 {Omega}-cm{sup 2}/cell. improvements in manifolding are expected to provide much higher performance.

  7. Advanced alternate planar geometry solid oxide fuel cells

    SciTech Connect

    Elangovan, S.; Prouse, D.; Khandkar, A.; Donelson, R.; Marianowski, L. )

    1992-11-01

    The potential of high temperature Solid Oxide Fuel Cells as high performance, high efficiency energy conversion device is well known. Investigation of several cell designs have been undertaken by various researchers to derive the maximum performance benefit from the device while maintaining a lower cost of production to meet the commercialization cost target. The present investigation focused on the planar SOFC design which allows for the use of mature low cost production processes to be employed. A novel design concept was investigated which allows for improvements in performance through increased interface stability, and lowering of cost through enhanced structural integrity and the use of low cost metal interconnects. The new cell design consisted of a co-sintered porous/dense/porous zirconia layer with the electrode material infiltrated into the porous layers. The two year program conducted by a team involving Ceramatec and the Institute of Gas Technology, culminated in a multi-cell stack test that exhibited high performance. Considerable progress was achieved in the selection of cell components, and establishing and optimizing the cell and stack fabrication parameters. It was shown that the stack components exhibited high conductivities and low creep at the operating temperature. The inter-cell resistive losses were shown to be small through out-of-cell characterization. The source of performance loss was identified to be the anode electrolyte interface. This loss however can be minimized by improving the anode infiltration technique. Manifolding and sealing of the planar devices posed considerable challenge. Even though the open circuit voltage was 250 mV/cell lower than theoretical, the two cell stack had a performance of 300 mA/cm[sup 2] at 0.4V/cell with an area specific resistance of 1 [Omega]-cm[sup 2]/cell. improvements in manifolding are expected to provide much higher performance.

  8. Mineralization of paracetamol in aqueous solution with advanced oxidation processes.

    PubMed

    Torun, Murat; Gültekin, Özge; Şolpan, Dilek; Güven, Olgun

    2015-01-01

    Paracetamol is a common analgesic drug widely used in all regions of the world more than hundred tonnes per year and it poses a great problem for the aquatic environment. Its phenolic intermediates are classified as persistent organic pollutants and toxic for the environment as well as human beings. In the present study, the irradiation of aqueous solutions of paracetamol with 60Co gamma-rays was examined on a laboratory scale and its degradation path was suggested with detected radiolysis products. The synergic effect of ozone on gamma-irradiation was investigated by preliminary ozonation before irradiation which reduced the irradiation dose from 5 to 3 kGy to completely remove paracetamol and its toxic intermediate hydroquinone from 6 to 4 kGy as well as increasing the radiation chemical yield (Gi values 1.36 and 1.66 in the absence and presence of ozone, respectively). The observed amount of formed hydroquinone was also decreased in the presence of ozone. There is a decrease in pH from 6.4 to 5.2 and dissolved oxygen consumed, which is up to 0.8 mg l(-1), to form some peroxyl radicals used for oxidation. Analytical measurements were carried out with gas chromatography/mass spectrometry and ion chromatography (IC) both qualitatively and quantitatively. Amounts of paracetamol and hydroquinone were measured with gas chromatography after trimethylsilane derivatization. Small aliphatic acids, such as acetic acid, formic acid and oxalic acid, were measured quantitatively with IC as well as inorganic ions (nitrite and nitrate) in which their yields increase with irradiation.

  9. Advanced alternate planar geometry solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Elangovan, S.; Prouse, D.; Khandkar, A.; Donelson, R.; Marianowski, L.

    1992-11-01

    The potential of high temperature Solid Oxide Fuel Cells (SOFC) as high performance, high efficiency energy conversion devices is well known. Investigation of several cell designs have been undertaken by various researchers to derive the maximum performance benefit from the device while maintaining a lower cost of production to meet the commercialization cost target. The present investigation focused on the planar SOFC design which allows for the use of mature low cost production processes. A novel design concept was investigated which allows for the following: improvements in performance through increased interface stability, and lowering of cost through enhanced structural integrity and the use of low cost metal interconnects. The new cell design consisted of a co-sintered porous/dense/porous zirconia layer with the electrode material infiltrated into the porous layers. The two year program conducted by a team involving Ceramatec and the Institute of Gas Technology culminated in a multi-cell stack test that exhibited high performance. Considerable progress was achieved in the selection of cell components and establishing and optimizing the cell and stack fabrication parameters. It was shown that the stack components exhibited high conductivities and low creep at the operating temperature. The inter-cell resistive losses were shown to be small through out-of-cell characterization. The source of performance loss was identified to be the anode electrolyte interface. This loss however can be minimized by improving the anode infiltration technique. Manifolding and sealing of the planar devices posed considerable challenge. Even though the open circuit voltage was 250 mV/cell lower than theoretical, the two cell stack had a performance of 300 mA/sq cm at 0.4V/cell with an area specific resistance of 1 Ohm-sq cm/cell. Improvements in manifolding are expected to provide much higher performance.

  10. Degenerate epitaxy-driven defects in monolayer silicon oxide on ruthenium

    NASA Astrophysics Data System (ADS)

    Mathur, Shashank; Vlaic, Sergio; Machado-Charry, Eduardo; Vu, Anh-Duc; Guisset, Valérie; David, Philippe; Hadji, Emmanuel; Pochet, Pascal; Coraux, Johann

    2015-10-01

    The structure of the ultimately thin crystalline allotrope of silicon oxide, prepared on a ruthenium surface, is unveiled down to the atomic scale with chemical sensitivity, owing to high resolution scanning tunneling microscopy and first principles calculations. An ordered oxygen lattice is imaged which coexists with the two-dimensional monolayer oxide. This coexistence signals a displacive transformation from an oxygen-reconstructed Ru(0001) to silicon oxide, along which laterally shifted domains form, each with equivalent and degenerate epitaxial relationships with the substrate. The unavoidable character of defects at the boundaries between these domains appeals for the development of alternative methods capable of producing single-crystalline two-dimensional oxides.

  11. Nanophase Manganese Oxides: Chemisorbed Water and Small Particle Size Promote Large Thermodynamically Driven Shifts in Oxidation-Reduction Equilibria

    NASA Astrophysics Data System (ADS)

    Birkner, N.; Navrotsky, A.

    2011-12-01

    Manganese oxides are important in terrestrial and Martian settings, and changes in oxidation state (Mn 2+, 3+, 4+) produce different phases. This study focuses on changes in redox energetics at the nanoscale in the Mn-O system with water present. Nanophase hausmannite (Mn3O4), bixbyite (Mn2O3), and pyrolusite (MnO2) were synthesized using minor modifications of previously published methods, stored at room temperature, and then analyzed by powder-XRD, BET surface area measurement, and TGA for total water content. High-temperature oxide-melt drop solution calorimetry was performed on a series of characterized samples with known surface area and water content. The differential heat of water adsorption as a function of coverage was also measured. The surface enthalpies of manganese oxide phases, hausmannite (Mn3O4), bixbyite (Mn2O3), and pyrolusite (MnO2), were determined using the data from high-temperature oxide melt calorimetry and water adsorption calorimetry. Surface energy for the hydrous Mn3O4 tetragonal spinel phase is 0.96±0.08 J/m2, for Mn2O3 cubic phase is 1.29±0.10 J/m2, and for MnO2 cubic rutile phase is 1.64±0.10 J/m2. Surface energy for the anhydrous Mn3O4 is 1.31±0.08 J/m2, for Mn2O3 is 1.57±0.10 J/m2, and for MnO2 is 1.99±0.10 J/m2. Supporting preliminary findings, the spinel phase (hausmannite) has a lower surface energy than bixbyite, while the latter has a smaller surface energy than pyrolusite. We also observed phase changes, some of them rapidly reversible, associated with water adsorption/desorption for the nanophase manganese oxide assemblages. There are geochemical consequences. (1) At the nanoscale, both the pyrolusite/bixbyite and bixbyite/hausmannite equilibria are shifted to higher oxygen fugacity because the reduced phase has the lower surface energy. (2) The ready inter-conversion of phases with different oxidation states under aqueous conditions implies that, after a manganese oxide nanophase forms, it can easily transform to other

  12. Reaction-driven surface restructuring and selectivity control in allylic alcohol catalytic aerobic oxidation over Pd.

    PubMed

    Lee, Adam F; Ellis, Christine V; Naughton, James N; Newton, Mark A; Parlett, Christopher M A; Wilson, Karen

    2011-04-20

    Synchronous, time-resolved DRIFTS/MS/XAS cycling studies of the vapor-phase selective aerobic oxidation of crotyl alcohol over nanoparticulate Pd have revealed surface oxide as the desired catalytically active phase, with dynamic, reaction-induced Pd redox processes controlling selective versus combustion pathways.

  13. Mass Spectrometry-Based Methods for Identifying Oxidized Proteins in Disease: Advances and Challenges

    PubMed Central

    Verrastro, Ivan; Pasha, Sabah; Tveen Jensen, Karina; Pitt, Andrew R.; Spickett, Corinne M.

    2015-01-01

    Many inflammatory diseases have an oxidative aetiology, which leads to oxidative damage to biomolecules, including proteins. It is now increasingly recognized that oxidative post-translational modifications (oxPTMs) of proteins affect cell signalling and behaviour, and can contribute to pathology. Moreover, oxidized proteins have potential as biomarkers for inflammatory diseases. Although many assays for generic protein oxidation and breakdown products of protein oxidation are available, only advanced tandem mass spectrometry approaches have the power to localize specific oxPTMs in identified proteins. While much work has been carried out using untargeted or discovery mass spectrometry approaches, identification of oxPTMs in disease has benefitted from the development of sophisticated targeted or semi-targeted scanning routines, combined with chemical labeling and enrichment approaches. Nevertheless, many potential pitfalls exist which can result in incorrect identifications. This review explains the limitations, advantages and challenges of all of these approaches to detecting oxidatively modified proteins, and provides an update on recent literature in which they have been used to detect and quantify protein oxidation in disease. PMID:25874603

  14. IRON OPTIMIZATION FOR FENTON-DRIVEN OXIDATION OF MTBE-SPENT GRANULAR ACTIVATED CARBON

    EPA Science Inventory

    Fenton-driven chemical regeneration of granular activated carbon (GAC) is accomplished through the addition of H2O2 and iron (Fe) to spent GAC. The overall objective of this treatment process is to transform target contaminants into less toxic byproducts, re-establish the sorpti...

  15. P450BM3 fused to phosphite dehydrogenase allows phosphite-driven selective oxidations.

    PubMed

    Beyer, Nina; Kulig, Justyna K; Bartsch, Anette; Hayes, Martin A; Janssen, Dick B; Fraaije, Marco W

    2017-03-01

    To facilitate the wider application of the NADPH-dependent P450BM3, we fused the monooxygenase with a phosphite dehydrogenase (PTDH). The resulting monooxygenase-dehydrogenase fusion enzyme acts as a self-sufficient bifunctional catalyst, accepting phosphite as a cheap electron donor for the regeneration of NADPH.The well-expressed fusion enzyme was purified and analyzed in comparison to the parent enzymes. Using lauric acid as substrate for P450BM3, it was found that the fusion enzyme had similar substrate affinity and hydroxylation selectivity while it displayed a significantly higher activity than the non-fused monooxygenase. Phosphite-driven conversions of lauric acid at restricted NADPH concentrations confirmed multiple turnovers of the cofactor. Interestingly, both the fusion enzyme and the native P450BM3 displayed enzyme concentration dependent activity and the fused enzyme reached optimal activity at a lower enzyme concentration. This suggests that the fusion enzyme has an improved tendency to form functional oligomers.To explore the constructed phosphite-driven P450BM3 as a biocatalyst, conversions of the drug compounds omeprazole and rosiglitazone were performed. PTDH-P450BM3 driven by phosphite was found to be more efficient in terms of total turnover when compared with P450BM3 driven by NADPH. The results suggest that PTDH-P450BM3 is an attractive system for use in biocatalytic and drug metabolism studies.

  16. IRON OPTIMIZATION FOR FENTON-DRIVEN OXIDATION OF MTBE-SPENT GRANULAR ACTIVATED CARBON

    EPA Science Inventory

    Fenton-driven chemical regeneration of granular activated carbon (GAC) is accomplished through the addition of H2O2 and iron (Fe) to spent GAC. The overall objective of this treatment process is to transform target contaminants into less toxic byproducts, re-establish the sorpti...

  17. Inflammation-induced chondrocyte hypertrophy is driven by receptor for advanced glycation end products.

    PubMed

    Cecil, Denise L; Johnson, Kristen; Rediske, John; Lotz, Martin; Schmidt, Ann Marie; Terkeltaub, Robert

    2005-12-15

    The multiligand receptor for advanced glycation end products (RAGE) mediates certain chronic vascular and neurologic degenerative diseases accompanied by low-grade inflammation. RAGE ligands include S100/calgranulins, a class of low-molecular-mass, calcium-binding polypeptides, several of which are chondrocyte expressed. Here, we tested the hypothesis that S100A11 and RAGE signaling modulate osteoarthritis (OA) pathogenesis by regulating a shift in chondrocyte differentiation to hypertrophy. We analyzed human cartilages and cultured human articular chondrocytes, and used recombinant human S100A11, soluble RAGE, and previously characterized RAGE-specific blocking Abs. Normal human knee cartilages demonstrated constitutive RAGE and S100A11 expression, and RAGE and S100A11 expression were up-regulated in OA cartilages studied by immunohistochemistry. CXCL8 and TNF-alpha induced S100A11 expression and release in cultured chondrocytes. Moreover, S100A11 induced cell size increase and expression of type X collagen consistent with chondrocyte hypertrophy in vitro. CXCL8-induced, IL-8-induced, and TNF-alpha-induced but not retinoic acid-induced chondrocyte hypertrophy were suppressed by treatment with soluble RAGE or RAGE-specific blocking Abs. Last, via transfection of dominant-negative RAGE and dominant-negative MAPK kinase 3, we demonstrated that S100A11-induced chondrocyte type X collagen expression was dependent on RAGE-mediated p38 MAPK pathway activation. We conclude that up-regulated chondrocyte expression of the RAGE ligand S100A11 in OA cartilage, and RAGE signaling through the p38 MAPK pathway, promote inflammation-associated chondrocyte hypertrophy. RAGE signaling thereby has the potential to contribute to the progression of OA.

  18. Treeline advances along the Urals mountain range - driven by improved winter conditions?

    PubMed

    Hagedorn, Frank; Shiyatov, Stepan G; Mazepa, Valeriy S; Devi, Nadezhda M; Grigor'ev, Andrey A; Bartysh, Alexandr A; Fomin, Valeriy V; Kapralov, Denis S; Terent'ev, Maxim; Bugman, Harald; Rigling, Andreas; Moiseev, Pavel A

    2014-11-01

    High-altitude treelines are temperature-limited vegetation boundaries, but little quantitative evidence exists about the impact of climate change on treelines in untouched areas of Russia. Here, we estimated how forest-tundra ecotones have changed during the last century along the Ural mountains. In the South, North, Sub-Polar, and Polar Urals, we compared 450 historical and recent photographs and determined the ages of 11,100 trees along 16 altitudinal gradients. In these four regions, boundaries of open and closed forests (crown covers above 20% and 40%) expanded upwards by 4 to 8 m in altitude per decade. Results strongly suggest that snow was an important driver for these forest advances: (i) Winter precipitation has increased substantially throughout the Urals (~7 mm decade(-1) ), which corresponds to almost a doubling in the Polar Urals, while summer temperatures have only changed slightly (~0.05°C decade(-1) ). (ii) There was a positive correlation between canopy cover, snow height and soil temperatures, suggesting that an increasing canopy cover promotes snow accumulation and, hence, a more favorable microclimate. (iii) Tree age analysis showed that forest expansion mainly began around the year 1900 on concave wind-sheltered slopes with thick snow covers, while it started in the 1950s and 1970s on slopes with shallower snow covers. (iv) During the 20th century, dominant growth forms of trees have changed from multistemmed trees, resulting from harsh winter conditions, to single-stemmed trees. While 87%, 31%, and 93% of stems appearing before 1950 were from multistemmed trees in the South, North and Polar Urals, more than 95% of the younger trees had a single stem. Currently, there is a high density of seedlings and saplings in the forest-tundra ecotone, indicating that forest expansion is ongoing and that alpine tundra vegetation will disappear from most mountains of the South and North Urals where treeline is already close to the highest peaks. © 2014

  19. Oxygen Penalty for Waste Oxidation in an Advanced Life Support System: A Systems Approach

    NASA Technical Reports Server (NTRS)

    Pisharody, Suresh; Wignarajah, K.; Fisher, John

    2002-01-01

    Oxidation is one of a number of technologies that are being considered for waste management and resource recovery from waste materials generated on board space missions. Oxidation processes are a very effective and efficient means of clean and complete conversion of waste materials to sterile products. However, because oxidation uses oxygen there is an "oxygen penalty" associated either with resupply of oxygen or with recycling oxygen from some other source. This paper is a systems approach to the issue of oxygen penalty in life support systems and presents findings on the oxygen penalty associated with an integrated oxidation-Sabatier-Oxygen Generation System (OGS) for waste management in an Advanced Life Support System. The findings reveal that such an integrated system can be operated to form a variety of useful products without a significant oxygen penalty.

  20. Novel designs of microwave discharge electrodeless lamps (MDEL) in photochemical applications. Use in advanced oxidation processes.

    PubMed

    Horikoshi, Satoshi; Abe, Masahiko; Serpone, Nick

    2009-08-01

    Novel light sources based on microwave discharge electrodeless lamps (MDEL) are examined as potential light sources to drive photochemical processes, in particular advanced oxidation processes (AOPs) of which various applications are described. The MDELs possess several features that make them attractive as possible environmental remediation lamps and as light sources to activate metal oxide photocatalysts in environmental remediation processes. Accordingly, the article describes some of the many features, albeit non-exhaustively, of MDEL devices and reports some photoreactors that incorporate these MDELs. Fundamental issues of MDEL light sources in remediation processing of actual pollutants are introduced. Examples are taken from the oxidative destruction of volatile organic compounds (VOCs; e.g. acetaldehyde and toluene), from the oxidative degradation of contaminants present in wastewaters (e.g. the 2,4-D herbicide and the endocrine disruptor bisphenol-A) and from the remediation of dioxin-contaminated fly-ash, along with an actual industrial wastewater sample from the manufacturing of cement.

  1. Experimental Study of Advanced Treatment of Coking Wastewater Using PFS Coagulation-Photocatalytic Oxidation Technology

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Wang, Lina; Liu, Pu; Fu, Benquan; Hwang, Jiannyang; Chen, Shining

    A PFS(polymeric ferric sulfate) coagulation-photocatalytic oxidation technology was used for advanced treatment of coking wastewater from secondary biological treatment. Effects of some key factors on TOC removal rate were investigated, and the results were compared with those of the common photocatalytic oxidation technology under the operating parameters of the photocatalytic oxidation defined. Single factor experimental results showed that TOC removal rate could reach 81%, when optimal operating conditions were as follows: TiO2 loading: 4.0g/L, irradiation time: 4h, initial pH is 5.1and PFS dosage:700mg/L. PFS coagulation and photocatalytic oxidation have synergistic effect, which is meaningful for highly efficient treatment of coking wastewater.

  2. Recent advances (2010-2015) in studies of cerium oxide nanoparticles' health effects.

    PubMed

    Li, Yan; Li, Peng; Yu, Hua; Bian, Ying

    2016-06-01

    Cerium oxide nanoparticles, widespread applied in our life, have attracted much concern for their human health effects. However, most of the works addressing cerium oxide nanoparticles toxicity have only used in vitro models or in vivo intratracheal instillation methods. The toxicity studies have varied results and not all are conclusive. The information about risk assessments derived from epidemiology studies is severely lacking. The knowledge of occupational safety and health (OSH) for exposed workers is very little. Thus this review focuses on recent advances in studies of toxicokinetics, antioxidant activity and toxicity. Additionally, aim to extend previous health effects assessments of cerium oxide nanoparticles, we summarize the epidemiology studies of engineered cerium oxide nanoparticles used as automotive diesel fuel additive, aerosol particulate matter in air pollution, other industrial ultrafine and nanoparticles (e.g., fumes particles generated in welding and flame cutting processes).

  3. Application of UV based advanced oxidation to treat sulfolane in an aqueous medium.

    PubMed

    Yu, Linlong; Mehrabani-Zeinabad, Mitra; Achari, Gopal; Langford, Cooper H

    2016-10-01

    Several oxidative methods were studied to degrade sulfolane in an aqueous medium. These include UVA and UVC irradiation with suitable photoactive oxidants, including ozone, H2O2, and TiO2 based photocatalysis and their combinations. Since sulfolane lacks absorption bands in the UV range beyond 200 nm, initiation of reactions depends on the spectra and photochemistry of the oxidants. Among all the advanced oxidation processes investigated, combinations of (a) UVC with H2O2 and O3 (b) UVC with H2O2 and (c) UVC with O3 led to the highest rate of sulfolane loss in synthetic water samples. Experiments on sulfolane contaminated groundwater samples also indicated that these three combinations can efficiently degrade sulfolane. Furthermore, a synergistic effect was observed in the combination of H2O2 and O3 photolysis.

  4. A pilot scale comparison of advanced oxidation processes for estrogenic hormone removal from municipal wastewater effluent.

    PubMed

    Pešoutová, Radka; Stříteský, Luboš; Hlavínek, Petr

    2014-01-01

    This study investigates the oxidation of selected endocrine disrupting compounds (estrone, 17β-estradiol, estriol and 17α-ethinylestradiol) during ozonation and advanced oxidation of biologically treated municipal wastewater effluents in a pilot scale. Selected estrogenic substances were spiked in the treated wastewater at levels ranging from 1.65 to 3.59 μg · L(-1). All estrogens were removed by ozonation by more than 99% at ozone doses ≥1.8 mg · L(-1). At a dose of 4.4 · mg L(-1) ozonation reduced concentrations of estrone, 17β-estradiol, estriol and 17α-ethinylestradiol by 99.8, 99.7, 99.9 and 99.7%, respectively. All tested advanced oxidation processes (AOPs) achieved high removal rates but they were slightly lower compared to ozonation. The lower removal rates for all tested advanced oxidation processes are caused by the presence of naturally occurring hydroxyl radical scavengers - carbonates and bicarbonates.

  5. Biological efficacy and toxic effect of emergency water disinfection process based on advanced oxidation technology.

    PubMed

    Tian, Yiping; Yuan, Xiaoli; Xu, Shujing; Li, Rihong; Zhou, Xinying; Zhang, Zhitao

    2015-12-01

    An innovative and removable water treatment system consisted of strong electric field discharge and hydrodynamic cavitation based on advanced oxidation technologies was developed for reactive free radicals producing and waterborne pathogens eliminating in the present study. The biological efficacy and toxic effects of this advanced oxidation system were evaluated during water disinfection treatments. Bench tests were carried out with synthetic microbial-contaminated water, as well as source water in rainy season from a reservoir of Dalian city (Liaoning Province, China). Results showed that high inactivation efficiency of Escherichia coli (>5 log) could be obtained for synthetic contaminated water at a low concentration (0.5-0.7 mg L(-1)) of total oxidants in 3-10 s. The numbers of wild total bacteria (108 × 10(3) CFU mL(-1)) and total coliforms (260 × 10(2) MPN 100 mL(-1)) in source water greatly reduced to 50 and 0 CFU mL(-1) respectively after treated by the advanced oxidation system, which meet the microbiological standards of drinking water, and especially that the inactivation efficiency of total coliforms could reach 100%. Meanwhile, source water qualities were greatly improved during the disinfection processes. The values of UV254 in particular were significantly reduced (60-80%) by reactive free radicals. Moreover, the concentrations of possible disinfection by-products (formaldehyde and bromide) in treated water were lower than detection limits, indicating that there was no harmful effect on water after the treatments. These investigations are helpful for the ecotoxicological studies of advanced oxidation system in the treatments of chemical polluted water or waste water. The findings of this work suggest that the developed water treatment system is ideal in the acute phases of emergencies, which also could offer additional advantages over a wide range of applications in water pollution control.

  6. Light driven water oxidation by a single site cobalt salophen catalyst.

    PubMed

    Pizzolato, Erica; Natali, Mirco; Posocco, Bianca; Montellano López, Alejandro; Bazzan, Irene; Di Valentin, Marilena; Galloni, Pierluca; Conte, Valeria; Bonchio, Marcella; Scandola, Franco; Sartorel, Andrea

    2013-11-04

    A salophen cobalt(II) complex enables water oxidation at neutral pH in photoactivated sacrificial cycles under visible light, thus confirming the high appeal of earth abundant single site catalysis for artificial photosynthesis.

  7. Efficient removal of insecticide "imidacloprid" from water by electrochemical advanced oxidation processes.

    PubMed

    Turabik, Meral; Oturan, Nihal; Gözmen, Belgin; Oturan, Mehmet A

    2014-01-01

    The oxidative degradation of imidacloprid (ICP) has been carried out by electrochemical advanced oxidation processes (EAOPs), anodic oxidation, and electro-Fenton, in which hydroxyl radicals are generated electrocatalytically. Carbon-felt cathode and platinum or boron-doped diamond (BDD) anodes were used in electrolysis cell. To determine optimum operating conditions, the effects of applied current and catalyst concentration were investigated. The decay of ICP during the oxidative degradation was well fitted to pseudo-first-order reaction kinetics and absolute rate constant of the oxidation of ICP by hydroxyl radicals was found to be k abs(ICP) = 1.23 × 10(9) L mol(-1) s(-1). The results showed that both anodic oxidation and electro-Fenton process with BDD anode exhibited high mineralization efficiency reaching 91 and 94% total organic carbon (TOC) removal at 2 h, respectively. For Pt-EF process, mineralization efficiency was also obtained as 71%. The degradation products of ICP were identified and a plausible general oxidation mechanism was proposed. Some of the main reaction intermediates such as 6-chloronicotinic acid, 6-chloronicotinaldehyde, and 6-hydroxynicotinic acid were determined by GC-MS analysis. Before complete mineralization, formic, acetic, oxalic, and glyoxylic acids were identified as end-products. The initial chlorine and organic nitrogen present in ICP were found to be converted to inorganic anions Cl(-), NO₃(-), and NH₄(+).

  8. Evidence for roles of radicals in protein oxidation in advanced human atherosclerotic plaque.

    PubMed Central

    Fu, S; Davies, M J; Stocker, R; Dean, R T

    1998-01-01

    Oxidative damage might be important in atherogenesis. Oxidized lipids are present at significant concentrations in advanced human plaque, although tissue antioxidants are mostly present at normal concentrations. Indirect evidence of protein modification (notably derivatization of lysine) or oxidation has been obtained by immunochemical methods; the specificities of these antibodies are unclear. Here we present chemical determinations of six protein-bound oxidation products: dopa, o-tyrosine, m-tyrosine, dityrosine, hydroxyleucine and hydroxyvaline, some of which reflect particularly oxy-radical-mediated reaction pathways, which seem to involve mainly the participation of transition- metal ions. We compared the relative abundance of these oxidation products in normal intima, and in human carotid plaque samples with that observed after radiolytically generated hydroxyl radical attack on BSA in vitro. The close similarities in relative abundances in the latter two circumstances indicate that hydroxyl radical damage might occur in plaque. The relatively higher level of dityrosine in plaque than that observed after radiolysis suggests the additional involvement of HOCl-mediated reactions in advanced plaque. PMID:9677308

  9. Advanced Multi-Component Defect Cluster Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    1990-01-01

    The advantages of using ceramic thermal barrier coatings in gas turbine engine hot sections include increased fuel efficiency and improved engine reliability. However, current thermal barrier coatings will not have the low thermal conductivity and necessary sintering resistance under higher operating temperatures and thermal gradients required by future advanced ultra-efficient and low-emission aircraft engines. In this paper, a novel oxide defect cluster design approach is described for achieving low thermal conductivity and excellent thermal stability of the thermal barrier coating systems. This approach utilizes multi-component rare earth and other metal cluster oxide dopants that are incorporated in the zirconia-yttria based systems, thus significantly reducing coating thermal conductivity and sintering resistance by effectively promoting the formation of thermodynamically stable, essentially immobile defect clusters and/or nanoscale phases. The performance of selected plasma-sprayed cluster oxide thermal barrier coating systems has been evaluated. The advanced multi-component thermal barrier coating systems were found to have significantly lower initial and long-term thermal conductivities, and better high temperature stability. The effect of oxide cluster dopants on coating thermal conductivity, sintering resistance, oxide grain growth behavior and durability will be discussed.

  10. Advanced Multi-Component Defect Cluster Oxide Doped Zirconia-Yttria Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    2003-01-01

    The advantages of using ceramic thermal barrier coatings in gas turbine engine hot sections include increased fuel efficiency and improved engine reliability. However, current thermal barrier coatings will not have the low thermal conductivity and necessary sintering resistance under higher operating temperatures and thermal gradients required by future advanced ultra efficient and low emission aircraft engines. In this paper, a novel oxide defect cluster design approach is described for achieving low thermal conductivity and excellent thermal stability of the thermal barrier coating systems. This approach utilizes multi-component rare earth and other metal cluster oxide dopants that are incorporated in the zirconia-yttna based systems, thus significantly reducing coating thermal conductivity and sintering resistance by effectively promoting the formation of thermodynamically stable, essentially immobile defect clusters and/or nanoscale phases. The performance of selected plasma-sprayed cluster oxide thermal barrier coating systems has been evaluated. The advanced multi-component thermal barrier coating systems were found to have significantly lower initial and long-term thermal conductivities, and better high temperature stability. The effect of oxide cluster dopants on coating thermal conductivity, sintering resistance, oxide grain growth behavior and durability will be discussed.

  11. Pathway-Driven Approaches of Interaction between Oxidative Balance and Genetic Polymorphism on Metabolic Syndrome

    PubMed Central

    2017-01-01

    Despite evidences of association between basic redox biology and metabolic syndrome (MetS), few studies have evaluated indices that account for multiple oxidative effectors for MetS. Oxidative balance score (OBS) has indicated the role of oxidative stress in chronic disease pathophysiology. In this study, we evaluated OBS as an oxidative balance indicator for estimating risk of MetS with 6414 study participants. OBS is a multiple exogenous factor score for development of disease; therefore, we investigated interplay between oxidative balance and genetic variation for development of MetS focusing on biological pathways by using gene-set-enrichment analysis. As a result, participants in the highest quartile of OBS were less likely to be at risk for MetS than those in the lowest quartile. In addition, persons in the highest quartile of OBS had the lowest level of inflammatory markers including C-reactive protein and WBC. With GWAS-based pathway analysis, we found that VEGF signaling pathway, glutathione metabolism, and Rac-1 pathway were significantly enriched biological pathways involved with OBS on MetS. These findings suggested that mechanism of angiogenesis, oxidative stress, and inflammation can be involved in interaction between OBS and genetic variation on risk of MetS. PMID:28191276

  12. In Vitro Oxidation of Collagen Promotes the Formation of Advanced Oxidation Protein Products and the Activation of Human Neutrophils.

    PubMed

    Bochi, Guilherme Vargas; Torbitz, Vanessa Dorneles; de Campos, Luízi Prestes; Sangoi, Manuela Borges; Fernandes, Natieli Flores; Gomes, Patrícia; Moretto, Maria Beatriz; Barbisan, Fernanda; da Cruz, Ivana Beatrice Mânica; Moresco, Rafael Noal

    2016-04-01

    The accumulation of advanced oxidation protein products (AOPPs) has been linked to several pathological conditions. Here, we investigated collagen as a potential source for AOPP formation and determined the effects of hypochlorous acid (HOCl)-treated collagen (collagen-AOPPs) on human neutrophil activity. We also assessed whether alpha-tocopherol could counteract these effects. Exposure to HOCl increased the levels of collagen-AOPPs. Collagen-AOPPs also stimulated the production of AOPPs, nitric oxide (NO), superoxide radicals (O2(-)), and HOCl by neutrophils. Collagen-AOPPs induced apoptosis and decreased the number of viable cells. Alpha-tocopherol prevented the formation of collagen-AOPPs, strongly inhibited the collagen-AOPP-induced production of O2(-) and HOCl, and increased the viability of neutrophils. Our results suggest that collagen is an important protein that interacts with HOCl to form AOPPs, and consequently, collagen-AOPP formation is related to human neutrophil activation and cell death.

  13. Advanced oxidation technologies for the treatment of contaminated groundwater. Book chapter

    SciTech Connect

    Lewis, N.M.; Topudurti, K.

    1994-01-01

    The paper presents information on two pilot-field applications of advanced oxidation technologies for contaminated groundwater with organics. The Ultrox technology was demonstrated in 1989 with the U.S. Environmental Protection Agency's Superfund Innovative Technology Evaluation (SITE) program at the Lorentz Barrel and Drum (LB D) site in San Jose, California. Peroxidation Systems technology was applied at the Old O-Field site located within the Aberdeen Proving Ground, in Maryland. The information presented includes a description of the technologies, factors affecting the technologies, and results from the two pilot-scale studies of the UV/oxidation treatment system applications.

  14. Recent Progress in Using Advanced Characterization and Modeling Approaches to Study Radiation Effects in Oxide Ceramics

    DOE PAGES

    Bai, Xian-Ming

    2014-10-23

    I serve as a Guest Editor for the Nuclear Materials Committee of the TMS Structural Materials Division, and coordinated the topic ‘‘Radiation Effects in Oxide Ceramics and Novel LWR Fuels" for JOM in the December 2014 issue. I selected five articles related this topic. These articles talk about some recent progress of using advanced experimental and modeling tools to study radiation effects in oxide ceramics at atomistic scale and mesoscale. In this guest editor commentary article, I summarize the novel aspects of these papers and also provide some suggestions for future research directions.

  15. Degradation of 4-chlorophenol by microwave irradiation enhanced advanced oxidation processes.

    PubMed

    Zhihui, Ai; Peng, Yang; Xiaohua, Lu

    2005-08-01

    In this work the synergistic effects of several microwave assisted advanced oxidation processes (MW/AOPs) were studied for the degradation of 4-chlorophenol (4-CP). The efficiencies of the degradation of 4-CP in dilute aqueous solution for a variety of AOPs with or without MW irradiation were compared. The results showed that the synergistic effects between MW and H2O2, UV/H2O2, TiO2 photocatalytic oxidation (PCO) resulted in a high degradation efficiency for 4-CP. The potential of MW/AOPs for treatment of industrial wastewater is discussed.

  16. Identification of transformation products during advanced oxidation of diatrizoate: Effect of water matrix and oxidation process.

    PubMed

    Azerrad, Sara P; Lütke Eversloh, Christian; Gilboa, Maayan; Schulz, Manoj; Ternes, Thomas; Dosoretz, Carlos G

    2016-10-15

    Removal of micropollutants from reverse osmosis (RO) brines of wastewater desalination by oxidation processes is influenced by the scavenging capacity of brines components, resulting in the accumulation of transformation products (TPs) rather than complete mineralization. In this work the iodinated contrast media diatrizoate (DTZ) was used as model compound due to its relative resistance to oxidation. Identification of TPs was performed in ultrapure water (UPW) and RO brines applying nonthermal plasma (NTP) and UVA-TiO2 as oxidation techniques. The influence of main RO brines components in the formation and accumulation of TPs, such as chloride, bicarbonate alkalinity and humic acid, was also studied during UVA-TiO2. DTZ oxidation pattern in UPW resulted similar in both UVA-TiO2 and NTP achieving 66 and 61% transformation, respectively. However, DTZ transformation in RO brines was markedly lower in UVA-TiO2 (9%) than in NTP (27%). These differences can be attributed to the synergic effect of RO brines components during NTP. Moreover, reactive species other than hydroxyl radical contributed to DTZ transformation, i.e., direct photolysis in UVA-TiO2 and direct photolysis + O3 in NTP accounted for 16 and 23%, respectively. DTZ transformation led to iodide formation in both oxidation techniques but it further oxidized to iodate by ozone in NTP. In total 14 transformation products were identified in UPW of which 3 were present only in UVA-TiO2 and 2 were present exclusively in NTP; 5 of the 14 TPs were absent in RO brines. Five of them were new and were denoted as TP-474A/B, TP-522, TP-586, TP-602, TP-628. TP-522 (mono-chlorinated) was elucidated only in presence of high chloride titer-synthetic water matrix in NTP, most probably formed by active chlorine species generated in situ. TPs accumulation in RO brines was markedly different in comparison to UPW. This denotes the influence of RO brines components in the formation of reactive species that could further attack

  17. Advanced oxidation protein product levels as a marker of oxidative stress in paediatric patients with chronic tonsillitis.

    PubMed

    Ozbay, I; Kucur, C; Koçak, F E; Savran, B; Oghan, F

    2016-10-01

    We aimed to determine whether advanced oxidation protein product (AOPP) levels can serve as a marker of oxidative stress in paediatric patients with chronic tonsillitis. Thirty children with chronic tonsillitis and 30 healthy children (control group) were recruited from the Otorhinolaryngology (ORL) and Paediatric Surgery departments, respectively, of Dumlupinar University Hospital. In the patient group, blood samples were collected before tonsillectomy, and tonsil tissue was sampled during the operation. Blood samples were also obtained from the control subjects. AOPP levels in the serum and tonsil tissue were measured by the spectrophotometric method. Serum AOPP levels were significantly higher in the patient group (13.1 ± 3.3 ng/ml) than in the control group (11.6 ± 2.3 ng/ml; P < 0.05). In addition, the mean AOPP level (41.9 ± 13.5 ng/mg protein) in the tonsil tissue in the patient group was significantly higher than the mean serum AOPP levels in the control and patient groups (P < 0.05). AOPP levels are elevated in the tonsil tissue and serum of patients with chronic tonsillitis compared to the serum AOPP levels in healthy controls. AOPPs may represent a novel class of pro-inflammatory molecules that are involved in oxidative stress in chronic tonsillitis. AOPPs may be used as a marker of oxidative stress in paediatric patients with chronic tonsillitis. © Copyright by Società Italiana di Otorinolaringologia e Chirurgia Cervico-Facciale, Rome, Italy.

  18. Oxidative stress responses of Daphnia magna exposed to effluents spiked with emerging contaminants under ozonation and advanced oxidation processes.

    PubMed

    Oropesa, Ana Lourdes; Novais, Sara C; Lemos, Marco F L; Espejo, Azahara; Gravato, Carlos; Beltrán, Fernando

    2017-01-01

    Integration of conventional wastewater treatments with advanced oxidation processes (AOPs) has become of great interest to remove pharmaceuticals and their metabolites from wastewater. However, application of these technologies generates reactive oxygen species (ROS) that may reach superficial waters through effluents from sewage treatment plants. The main objective of the present study was to elucidate if ROS present in real effluents after biological and then chemical (single ozonation, solar photolytic ozonation, solar photocatalytic ozonation (TiO2, Fe3O4) and solar photocatalytic oxidation (TiO2)) treatments induce oxidative stress in Daphnia magna. For this, the activity of two antioxidant enzymes (superoxide dismutase and catalase) and the level of lipid peroxidation were determined in Daphnia. The results of oxidative stress biomarkers studied suggest that D. magna is able to cope with the superoxide ion radical (O2·(-)) present in the treated effluent due to single ozonation by mainly inducing the antioxidant activity superoxide dismutase, thus preventing lipid peroxidation. Lethal effects (measured in terms of immobility) were not observed in these organisms after exposure to any solution. Therefore, in order to probe the ecological efficiency of urban wastewater treatments, studies on lethal and sublethal effects in D. magna would be advisable.

  19. Dual wavelength imaging of a scrape-off layer in an advanced beam-driven field-reversed configuration

    SciTech Connect

    Osin, D.; Schindler, T.

    2016-11-15

    A dual wavelength imaging system has been developed and installed on C-2U to capture 2D images of a He jet in the Scrape-Off Layer (SOL) of an advanced beam-driven Field-Reversed Configuration (FRC) plasma. The system was designed to optically split two identical images and pass them through 1 nm FWHM filters. Dual wavelength images are focused adjacent on a large format CCD chip and recorded simultaneously with a time resolution down to 10 μs using a gated micro-channel plate. The relatively compact optical system images a 10 cm plasma region with a spatial resolution of 0.2 cm and can be used in a harsh environment with high electro-magnetic noise and high magnetic field. The dual wavelength imaging system provides 2D images of either electron density or temperature by observing spectral line pairs emitted by He jet atoms in the SOL. A large field of view, combined with good space and time resolution of the imaging system, allows visualization of macro-flows in the SOL. First 2D images of the electron density and temperature observed in the SOL of the C-2U FRC are presented.

  20. Self-Driven Desalination and Advanced Treatment of Wastewater in a Modularized Filtration Air Cathode Microbial Desalination Cell.

    PubMed

    Zuo, Kuichang; Wang, Zhen; Chen, Xi; Zhang, Xiaoyuan; Zuo, Jiaolan; Liang, Peng; Huang, Xia

    2016-07-05

    Microbial desalination cells (MDCs) extract organic energy from wastewater for in situ desalination of saline water. However, to desalinate salt water, traditional MDCs often require an anolyte (wastewater) and a catholyte (other synthetic water) to produce electricity. Correspondingly, the traditional MDCs also produced anode effluent and cathode effluent, and may produce a concentrate solution, resulting in a low production of diluate. In this study, nitrogen-doped carbon nanotube membranes and Pt carbon cloths were utilized as filtration material and cathode to fabricate a modularized filtration air cathode MDC (F-MDC). With real wastewater flowing from anode to cathode, and finally to the middle membrane stack, the diluate volume production reached 82.4%, with the removal efficiency of salinity and chemical oxygen demand (COD) reached 93.6% and 97.3% respectively. The final diluate conductivity was 68 ± 12 μS/cm, and the turbidity was 0.41 NTU, which were sufficient for boiler supplementary or industrial cooling. The concentrate production was only 17.6%, and almost all the phosphorus and salt, and most of the nitrogen were recovered, potentially allowing the recovery of nutrients and other chemicals. These results show the potential utility of the modularized F-MDC in the application of municipal wastewater advanced treatment and self-driven desalination.

  1. Dual wavelength imaging of a scrape-off layer in an advanced beam-driven field-reversed configuration

    NASA Astrophysics Data System (ADS)

    Osin, D.; Schindler, T.

    2016-11-01

    A dual wavelength imaging system has been developed and installed on C-2U to capture 2D images of a He jet in the Scrape-Off Layer (SOL) of an advanced beam-driven Field-Reversed Configuration (FRC) plasma. The system was designed to optically split two identical images and pass them through 1 nm FWHM filters. Dual wavelength images are focused adjacent on a large format CCD chip and recorded simultaneously with a time resolution down to 10 μs using a gated micro-channel plate. The relatively compact optical system images a 10 cm plasma region with a spatial resolution of 0.2 cm and can be used in a harsh environment with high electro-magnetic noise and high magnetic field. The dual wavelength imaging system provides 2D images of either electron density or temperature by observing spectral line pairs emitted by He jet atoms in the SOL. A large field of view, combined with good space and time resolution of the imaging system, allows visualization of macro-flows in the SOL. First 2D images of the electron density and temperature observed in the SOL of the C-2U FRC are presented.

  2. Integrated magnetic and kinetic control of advanced tokamak plasmas on DIII-D based on data-driven models

    NASA Astrophysics Data System (ADS)

    Moreau, D.; Walker, M. L.; Ferron, J. R.; Liu, F.; Schuster, E.; Barton, J. E.; Boyer, M. D.; Burrell, K. H.; Flanagan, S. M.; Gohil, P.; Groebner, R. J.; Holcomb, C. T.; Humphreys, D. A.; Hyatt, A. W.; Johnson, R. D.; La Haye, R. J.; Lohr, J.; Luce, T. C.; Park, J. M.; Penaflor, B. G.; Shi, W.; Turco, F.; Wehner, W.; the ITPA-IOS Group members; experts

    2013-06-01

    The first real-time profile control experiments integrating magnetic and kinetic variables were performed on DIII-D in view of regulating and extrapolating advanced tokamak scenarios to steady-state devices and burning plasma experiments. Device-specific, control-oriented models were obtained from experimental data using a generic two-time-scale method that was validated on JET, JT-60U and DIII-D under the framework of the International Tokamak Physics Activity for Integrated Operation Scenarios (Moreau et al 2011 Nucl. Fusion 51 063009). On DIII-D, these data-driven models were used to synthesize integrated magnetic and kinetic profile controllers. The neutral beam injection (NBI), electron cyclotron current drive (ECCD) systems and ohmic coil provided the heating and current drive (H&CD) sources. The first control actuator was the plasma surface loop voltage (i.e. the ohmic coil), and the available beamlines and gyrotrons were grouped to form five additional H&CD actuators: co-current on-axis NBI, co-current off-axis NBI, counter-current NBI, balanced NBI and total ECCD power from all gyrotrons (with off-axis current deposition). Successful closed-loop experiments showing the control of (a) the poloidal flux profile, Ψ(x), (b) the poloidal flux profile together with the normalized pressure parameter, βN, and (c) the inverse of the safety factor profile, \\bar{\\iota}(x)=1/q(x) , are described.

  3. Computational modeling of electrically-driven deposition of ionized polydisperse particulate powder mixtures in advanced manufacturing processes

    NASA Astrophysics Data System (ADS)

    Zohdi, T. I.

    2017-07-01

    A key part of emerging advanced additive manufacturing methods is the deposition of specialized particulate mixtures of materials on substrates. For example, in many cases these materials are polydisperse powder mixtures whereby one set of particles is chosen with the objective to electrically, thermally or mechanically functionalize the overall mixture material and another set of finer-scale particles serves as an interstitial filler/binder. Often, achieving controllable, precise, deposition is difficult or impossible using mechanical means alone. It is for this reason that electromagnetically-driven methods are being pursued in industry, whereby the particles are ionized and an electromagnetic field is used to guide them into place. The goal of this work is to develop a model and simulation framework to investigate the behavior of a deposition as a function of an applied electric field. The approach develops a modular discrete-element type method for the simulation of the particle dynamics, which provides researchers with a framework to construct computational tools for this growing industry.

  4. Guanylyl cyclase sensitivity to nitric oxide is protected by a thiol oxidation-driven interaction with thioredoxin-1.

    PubMed

    Huang, Can; Alapa, Maryam; Shu, Ping; Nagarajan, Narayani; Wu, Changgong; Sadoshima, Junichi; Kholodovych, Vladyslav; Li, Hong; Beuve, Annie

    2017-09-01

    Nitric oxide (NO) modulates many physiological events through production of cGMP from its receptor, the NO-sensitive guanylyl cyclase (GC1). NO also appears to function in a cGMP-independent manner, via S-nitrosation (SNO), a redox-based modification of cysteine thiols. Previously, we have shown that S-nitrosated GC1 (SNO-GC1) is desensitized to NO stimulation following prolonged NO exposure or under oxidative/nitrosative stress. In animal models of nitrate tolerance and angiotensin II-induced hypertension, decreased vasodilation in response to NO correlates with GC1 thiol oxidation, but the physiological mechanism that resensitizes GC1 to NO and restores basal activity is unknown. Because GC1 interacts with the oxidoreductase protein-disulfide isomerase, we hypothesized that thioredoxin-1 (Trx1), a cytosolic oxidoreductase, could be involved in restoring GC1 basal activity and NO sensitivity because the Trx/thioredoxin reductase (TrxR) system maintains thiol redox homeostasis. Here, by manipulating activity and levels of the Trx1/TrxR system and by using a Trx1-Trap assay, we demonstrate that Trx1 modulates cGMP synthesis through an association between Trx1 and GC1 via a mixed disulfide. A proximity ligation assay confirmed the endogenous Trx1-GC1 complex in cells. Mutational analysis suggested that Cys(609) in GC1 is involved in the Trx1-GC1 association and modulation of GC1 activity. Functionally, we established that Trx1 protects GC1 from S-nitrosocysteine-induced desensitization. A computational model of Trx1-GC1 interaction illustrates a possible mechanism for Trx1 to maintain basal GC1 activity and prevent/rescue GC1 desensitization to NO. The etiology of some oxidative vascular diseases may very well be explained by the dysfunction of the Trx1-GC1 association. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. Flower-like Cobalt Hydroxide/Oxide on Graphitic Carbon Nitride for Visible-Light-Driven Water Oxidation.

    PubMed

    Zhang, Huayang; Tian, Wenjie; Guo, Xiaochen; Zhou, Li; Sun, Hongqi; Tadé, Moses O; Wang, Shaobin

    2016-12-28

    Direct water oxidation via photocatalysis is a four-electron and multiple-proton process which requires high extra energy input to produce free dioxygen gas, making it exacting, especially under visible light irradiation. To improve the oxygen evolution reaction rates (OERs) and utilize more visible light, flower-like cobalt hydroxide/oxide (Fw-Co(OH)2/Fw-Co3O4) photocatalysts were prepared and loaded onto graphitic carbon nitride (g-C3N4) by a facile coating method in this work. Influenced by the unique three-dimensional morphologies, the synthesized Fw-Co(OH)2 or Fw-Co3O4/g-C3N4 hybrids reveal favorable combination and synergism reflected by the modified photoelectric activities and the improved OER performances. Attributed to its prominent hydrotalcite structure, Fw-Co(OH)2 shows better cocatalytic activity for g-C3N4 modification compared with that of Fw-Co3O4. Specifically, 7 wt % Fw-Co(OH)2/g-C3N4 photocatalyst exhibits photocurrent density 4 times higher and OER performance 5 times better than pristine g-C3N4. This work unambiguously promotes the application of sustainable g-C3N4 in water oxidation.

  6. Reduced TiO2-Graphene Oxide Heterostructure As Broad Spectrum-Driven Efficient Water-Splitting Photocatalysts.

    PubMed

    Li, Lihua; Yu, Lili; Lin, Zhaoyong; Yang, Guowei

    2016-04-06

    The reduced TiO2-graphene oxide heterostructure as an alternative broad spectrum-driven efficient water splitting photocatalyst has become a really interesting topic, however, its syntheses has many flaws, e.g., tedious experimental steps, time-consuming, small scale production, and requirement of various additives, for example, hydrazine hydrate is widely used as reductant to the reduction of graphene oxide, which is high toxicity and easy to cause the second pollution. For these issues, herein, we reported the synthesis of the reduced TiO2-graphene oxide heterostructure by a facile chemical reduction agent-free one-step laser ablation in liquid (LAL) method, which achieves extended optical response range from ultraviolet to visible and composites TiO(2-x) (reduced TiO2) nanoparticle and graphene oxide for promoting charge conducting. 30.64% Ti(3+) content in the reduced TiO2 nanoparticles induces the electronic reconstruction of TiO2, which results in 0.87 eV decrease of the band gap for the visible light absorption. TiO(2-x)-graphene oxide heterostructure achieved drastically increased photocatalytic H2 production rate, up to 23 times with respect to the blank experiment. Furthermore, a maximum H2 production rate was measured to be 16 mmol/h/g using Pt as a cocatalyst under the simulated sunlight irradiation (AM 1.5G, 135 mW/cm(2)), the quantum efficiencies were measured to be 5.15% for wavelength λ = 365 ± 10 nm and 1.84% for λ = 405 ± 10 nm, and overall solar energy conversion efficiency was measured to be 14.3%. These findings provided new insights into the broad applicability of this methodology for accessing fascinate photocatalysts.

  7. The study of leachate treatment by using three advanced oxidation process based wet air oxidation

    PubMed Central

    2013-01-01

    Wet air oxidation is regarded as appropriate options for wastewater treatment with average organic compounds. The general purpose of this research is to determine the efficiency of three wet air oxidation methods, wet oxidation with hydrogen peroxide and absorption with activated carbon in removing organic matter and nitrogenous compounds from Isfahan's urban leachate. A leachate sample with the volume of 1.5 liters entered into a steel reactor with the volume of three liters and was put under a 10-bar pressure, at temperatures of 100, 200, and 300° as well as three retention times of 30, 60, and 90 minutes. The sample was placed at 18 stages of leachate storage ponds in Isfahan Compost Plant with the volume of 20 liters, using three WPO, WAO methods and a combination of WAO/GAC for leachate pre-treatment. Thirty percent of pure oxygen and hydrogen peroxide were applied as oxidation agents. The COD removal efficiency in WAO method is 7.8-33.3%, in BOD is 14.7-50.6%, the maximum removal percentage (efficiency) for NH4-N is 53.3% and for NO3-N is 56.4-73.9%. The removal efficiency of COD and BOD5 is 4.6%-34 and 24%-50 respectively in WPO method. Adding GAC to the reactor, the removal efficiency of all parameters was improved. The maximum removal efficiency was increased 48% for COD, 31%-43.6 for BOD5 by a combinational method, and the ratio of BOD5/COD was also increased to 90%. In this paper, WAO and WPO process was used for Leachate pre-treatment and WAO/GAC combinational process was applied for improving the organic matter removal and leachate treatment; it was also determined that the recent process is much more efficient in removing resistant organic matter. PMID:23369258

  8. The study of leachate treatment by using three advanced oxidation process based wet air oxidation.

    PubMed

    Karimi, Behroz; Ehrampoush, Mohammad Hassan; Ebrahimi, Asghar; Mokhtari, Mehdi

    2013-01-02

    Wet air oxidation is regarded as appropriate options for wastewater treatment with average organic compounds. The general purpose of this research is to determine the efficiency of three wet air oxidation methods, wet oxidation with hydrogen peroxide and absorption with activated carbon in removing organic matter and nitrogenous compounds from Isfahan's urban leachate. A leachate sample with the volume of 1.5 liters entered into a steel reactor with the volume of three liters and was put under a 10-bar pressure, at temperatures of 100, 200, and 300° as well as three retention times of 30, 60, and 90 minutes. The sample was placed at 18 stages of leachate storage ponds in Isfahan Compost Plant with the volume of 20 liters, using three WPO, WAO methods and a combination of WAO/GAC for leachate pre-treatment. Thirty percent of pure oxygen and hydrogen peroxide were applied as oxidation agents. The COD removal efficiency in WAO method is 7.8-33.3%, in BOD is 14.7-50.6%, the maximum removal percentage (efficiency) for NH4-N is 53.3% and for NO3-N is 56.4-73.9%. The removal efficiency of COD and BOD5 is 4.6%-34 and 24%-50 respectively in WPO method. Adding GAC to the reactor, the removal efficiency of all parameters was improved. The maximum removal efficiency was increased 48% for COD, 31%-43.6 for BOD5 by a combinational method, and the ratio of BOD5/COD was also increased to 90%. In this paper, WAO and WPO process was used for Leachate pre-treatment and WAO/GAC combinational process was applied for improving the organic matter removal and leachate treatment; it was also determined that the recent process is much more efficient in removing resistant organic matter.

  9. Pre-treatment of penicillin formulation effluent by advanced oxidation processes.

    PubMed

    Arslan-Alaton, Idil; Dogruel, Serdar

    2004-08-09

    A variety of advanced oxidation processes (AOPs; O3/OH-, H2O2/UV, Fe2+/H2O2, Fe3+/H2O2, Fe2+/H2O2/UV and Fe3+/H2O2/UV) have been applied for the oxidative pre-treatment of real penicillin formulation effluent (average COD0 = 1395 mg/L; TOC0 = 920 mg/L; BOD(5,0) approximately 0 mg/L). For the ozonation process the primary involvement of free radical species such as OH* in the oxidative reaction could be demonstrated via inspection of ozone absorption rates. Alkaline ozonation and the photo-Fenton's reagents both appeared to be the most promising AOPs in terms of COD (49-66%) and TOC (42-52%) abatement rates, whereas the BOD5 of the originally non-biodegradable effluent could only be improved to a value of 100 mg/L with O3/pH = 3] treatment (BOD5/COD, f = 0.08). Evaluation on COD and TOC removal rates per applied active oxidant (AOx) and oxidant (Ox) on a molar basis revealed that alkaline ozonation and particularly the UV-light assisted Fenton processes enabling good oxidation yields (1-2 mol COD and TOC removal per AOx and Ox) by far outweighed the other studied AOPs. Separate experimental studies conducted with the penicillin active substance amoxicillin trihydrate indicated that the aqueous antibiotic substance can be completely eliminated after 40 min advanced oxidation applying photo-Fenton's reagent (pH = 3; Fe(2+):H2O2 molar ratio = 1:20) and alkaline ozonation (at pH = 11.5), respectively.

  10. Chemically Driven Enhancement of Oxygen Reduction Electrocatalysis in Supported Perovskite Oxides.

    PubMed

    Lee, Daehee; Tan, Jeiwan; Chae, Keun Hwa; Jeong, Beomgyun; Soon, Aloysius; Ahn, Sung-Jin; Kim, Joosun; Moon, Jooho

    2017-01-05

    Perovskite oxides have the capacity to efficiently catalyze the oxygen reduction reaction (ORR), which is of fundamental importance for electrochemical energy conversion. While the perovskite catalysts have been generally utilized with a support, the role of the supports, regarded as inert toward the ORR, has been emphasized mostly in terms of the thermal stability of the catalyst system and as an ancillary transport channel for oxygen ions during the ORR. We demonstrate a novel approach to improving the catalytic activity of perovskite oxides for solid oxide fuel cells by controlling the oxygen-ion conducting oxide supports. Catalytic activities of (La0.8Sr0.2)0.95MnO3 perovskite thin-film placed on different oxide supports are characterized by electrochemical impedance spectroscopy and X-ray absorption spectroscopy. These analyses confirm that the strong atomic orbital interactions between the support and the perovskite catalyst enhance the surface exchange kinetics by ∼2.4 times, in turn, improving the overall ORR activity.

  11. Oxidative stress-driven parvalbumin interneuron impairment as a common mechanism in models of schizophrenia

    PubMed Central

    Steullet, P; Cabungcal, J-H; Coyle, J; Didriksen, M; Gill, K; Grace, A A; Hensch, T K; LaMantia, A-S; Lindemann, L; Maynard, T M; Meyer, U; Morishita, H; O'Donnell, P; Puhl, M; Cuenod, M; Do, K Q

    2017-01-01

    Parvalbumin inhibitory interneurons (PVIs) are crucial for maintaining proper excitatory/inhibitory balance and high-frequency neuronal synchronization. Their activity supports critical developmental trajectories, sensory and cognitive processing, and social behavior. Despite heterogeneity in the etiology across schizophrenia and autism spectrum disorder, PVI circuits are altered in these psychiatric disorders. Identifying mechanism(s) underlying PVI deficits is essential to establish treatments targeting in particular cognition. On the basis of published and new data, we propose oxidative stress as a common pathological mechanism leading to PVI impairment in schizophrenia and some forms of autism. A series of animal models carrying genetic and/or environmental risks relevant to diverse etiological aspects of these disorders show PVI deficits to be all accompanied by oxidative stress in the anterior cingulate cortex. Specifically, oxidative stress is negatively correlated with the integrity of PVIs and the extracellular perineuronal net enwrapping these interneurons. Oxidative stress may result from dysregulation of systems typically affected in schizophrenia, including glutamatergic, dopaminergic, immune and antioxidant signaling. As convergent end point, redox dysregulation has successfully been targeted to protect PVIs with antioxidants/redox regulators across several animal models. This opens up new perspectives for the use of antioxidant treatments to be applied to at-risk individuals, in close temporal proximity to environmental impacts known to induce oxidative stress. PMID:28322275

  12. Advanced Catalysts for the Ambient Temperature Oxidation of Carbon Monoxide and Formaldehyde

    NASA Technical Reports Server (NTRS)

    Nalette, Tim; Eldridge, Christopher; Yu, Ping; Alpetkin, Gokhan; Graf, John

    2010-01-01

    The primary applications for ambient temperature carbon monoxide (CO) oxidation catalysts include emergency breathing masks and confined volume life support systems, such as those employed on the Shuttle. While Hopcalite is typically used in emergency breathing masks for terrestrial applications, in the 1970s, NASA selected a 2% platinum (Pt) on carbon for use on the Shuttle since it is more active and also more tolerant to water vapor. In the last 10-15 years there have been significant advances in ambient temperature CO oxidation catalysts. Langley Research Center developed a monolithic catalyst for ambient temperature CO oxidation operating under stoichiometric conditions for closed loop carbon dioxide (CO2) laser applications which is also advertised as having the potential to oxidize formaldehyde (HCHO) at ambient temperatures. In the last decade it has been discovered that appropriate sized nano-particles of gold are highly active for CO oxidation, even at sub-ambient temperatures, and as a result there has been a wealth of data reported in the literature relating to ambient/low temperature CO oxidation. In the shorter term missions where CO concentrations are typically controlled via ambient temperature oxidation catalysts, formaldehyde is also a contaminant of concern, and requires specially treated carbons such as Calgon Formasorb as untreated activated carbon has effectively no HCHO capacity. This paper examines the activity of some of the newer ambient temperature CO and formaldehyde (HCHO) oxidation catalysts, and measures the performance of the catalysts relative to the NASA baseline Ambient Temperature Catalytic Oxidizer (ATCO) catalyst at conditions of interest for closed loop trace contaminant control systems.

  13. Single Sublattice Endotaxial Phase Separation Driven by Charge Frustration in a Complex Oxide

    PubMed Central

    2013-01-01

    Complex transition-metal oxides are important functional materials in areas such as energy and information storage. The cubic ABO3 perovskite is an archetypal example of this class, formed by the occupation of small octahedral B-sites within an AO3 network defined by larger A cations. We show that introduction of chemically mismatched octahedral cations into a cubic perovskite oxide parent phase modifies structure and composition beyond the unit cell length scale on the B sublattice alone. This affords an endotaxial nanocomposite of two cubic perovskite phases with distinct properties. These locally B-site cation-ordered and -disordered phases share a single AO3 network and have enhanced stability against the formation of a competing hexagonal structure over the single-phase parent. Synergic integration of the distinct properties of these phases by the coherent interfaces of the composite produces solid oxide fuel cell cathode performance superior to that expected from the component phases in isolation. PMID:23750709

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

    PubMed Central

    Chen, Shi; Ng, Chin Fan; Huan, Cheng Hon Alfred

    2014-01-01

    Summary 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. PMID:24991486

  15. Adaptation of intertidal biofilm communities is driven by metal ion and oxidative stresses

    PubMed Central

    Zhang, Weipeng; Wang, Yong; Lee, On On; Tian, Renmao; Cao, Huiluo; Gao, Zhaoming; Li, Yongxin; Yu, Li; Xu, Ying; Qian, Pei-Yuan

    2013-01-01

    Marine organisms in intertidal zones are subjected to periodical fluctuations and wave activities. To understand how microbes in intertidal biofilms adapt to the stresses, the microbial metagenomes of biofilms from intertidal and subtidal zones were compared. The genes responsible for resistance to metal ion and oxidative stresses were enriched in both 6-day and 12-day intertidal biofilms, including genes associated with secondary metabolism, inorganic ion transport and metabolism, signal transduction and extracellular polymeric substance metabolism. In addition, these genes were more enriched in 12-day than 6-day intertidal biofilms. We hypothesize that a complex signaling network is used for stress tolerance and propose a model illustrating the relationships between these functions and environmental metal ion concentrations and oxidative stresses. These findings show that bacteria use diverse mechanisms to adapt to intertidal zones and indicate that the community structures of intertidal biofilms are modulated by metal ion and oxidative stresses. PMID:24212283

  16. Adaptation of intertidal biofilm communities is driven by metal ion and oxidative stresses.

    PubMed

    Zhang, Weipeng; Wang, Yong; Lee, On On; Tian, Renmao; Cao, Huiluo; Gao, Zhaoming; Li, Yongxin; Yu, Li; Xu, Ying; Qian, Pei-Yuan

    2013-11-11

    Marine organisms in intertidal zones are subjected to periodical fluctuations and wave activities. To understand how microbes in intertidal biofilms adapt to the stresses, the microbial metagenomes of biofilms from intertidal and subtidal zones were compared. The genes responsible for resistance to metal ion and oxidative stresses were enriched in both 6-day and 12-day intertidal biofilms, including genes associated with secondary metabolism, inorganic ion transport and metabolism, signal transduction and extracellular polymeric substance metabolism. In addition, these genes were more enriched in 12-day than 6-day intertidal biofilms. We hypothesize that a complex signaling network is used for stress tolerance and propose a model illustrating the relationships between these functions and environmental metal ion concentrations and oxidative stresses. These findings show that bacteria use diverse mechanisms to adapt to intertidal zones and indicate that the community structures of intertidal biofilms are modulated by metal ion and oxidative stresses.

  17. Metal Organic Chemical Vapor Deposition of Oxide Films for Advanced Applications

    DTIC Science & Technology

    2000-06-01

    recirculating forced convection flow in the system. Samples are heated by a fixed radiative heater below the rotating susceptor. Thermophoresis ...technology. FOCUS ON ZINC OXIDE TCO A natural outgrowth of display technology efforts is the development of advanced transparent and...studies emphasized surface morphology and preferred orientation effects , rather than the electrical and optical properties of ZnO films[1]. ZnO ceramics

  18. Infrared spectroscopy study of electrochromic nanocrystalline tungsten oxide films made by reactive advanced gas deposition

    NASA Astrophysics Data System (ADS)

    Solis, J. L.; Hoel, A.; Lantto, V.; Granqvist, C. G.

    2001-03-01

    Nanocrystalline W oxide films were produced by advanced reactive gas deposition. The material consisted of ˜6 nm diameter tetragonal crystallites, as found from x-ray diffraction and electron microscopy. Optoelectrochemical measurements demonstrated electrochromism upon Li+ intercalation/deintercalation, and infrared absorption spectroscopy gave clear evidence for longitudinal and transversal optical modes being modified following the lithiation. Our data were consistent with ionic transport predominantly in disordered grain boundaries and intercrystalline regions and with electrochromism being associated with small polaron formation.

  19. Endothelium-driven myocardial growth or nitric oxide at the crossroads

    PubMed Central

    Tirziu, Daniela; Simons, Michael

    2009-01-01

    Endothelium lining the coronary vasculature and the heart chambers is a dynamic sensor that serves a variety of functions including bi-directional communications with cardiac myocytes. Among endothelium-released factors nitric oxide exerts multifactorial effects on various cell types in the heart and may play a role in growth of the vasculature and myocardial hypertrophy. This review summarizes new data regarding the endothelium-to-myocyte signaling focusing on its role in regulation of cardiac hypertrophy through a nitric oxide mediated paracrine signal. PMID:19345317

  20. Gas-phase advanced oxidation for effective, efficient in situ control of pollution.

    PubMed

    Johnson, Matthew S; Nilsson, Elna J K; Svensson, Erik A; Langer, Sarka

    2014-01-01

    In this article, gas-phase advanced oxidation, a new method for pollution control building on the photo-oxidation and particle formation chemistry occurring in the atmosphere, is introduced and characterized. The process uses ozone and UV-C light to produce in situ radicals to oxidize pollution, generating particles that are removed by a filter; ozone is removed using a MnO2 honeycomb catalyst. This combination of in situ processes removes a wide range of pollutants with a comparatively low specific energy input. Two proof-of-concept devices were built to test and optimize the process. The laboratory prototype was built of standard ventilation duct and could treat up to 850 m(3)/h. A portable continuous-flow prototype built in an aluminum flight case was able to treat 46 m(3)/h. Removal efficiencies of >95% were observed for propane, cyclohexane, benzene, isoprene, aerosol particle mass, and ozone for concentrations in the range of 0.4-6 ppm and exposure times up to 0.5 min. The laboratory prototype generated a OH(•) concentration derived from propane reaction of (2.5 ± 0.3) × 10(10) cm(-3) at a specific energy input of 3 kJ/m(3), and the portable device generated (4.6 ± 0.4) × 10(9) cm(-3) at 10 kJ/m(3). Based on these results, in situ gas-phase advanced oxidation is a viable control strategy for most volatile organic compounds, specifically those with a OH(•) reaction rate higher than ca. 5 × 10(-13) cm(3)/s. Gas-phase advanced oxidation is able to remove compounds that react with OH and to control ozone and total particulate mass. Secondary pollution including formaldehyde and ultrafine particles might be generated, depending on the composition of the primary pollution.

  1. Comparison of different advanced oxidation processes for the degradation of two fluoroquinolone antibiotics in aqueous solutions.

    PubMed

    Bobu, Maria; Yediler, Ayfer; Siminiceanu, Ilie; Zhang, Feifang; Schulte-Hostede, Sigurd

    2013-01-01

    In this study a comparative assessment using various advanced oxidation processes (UV/H(2)O(2), UV/H(2)O(2)/Fe(II), O(3), O(3)/UV, O(3)/UV/H(2)O(2) and O(3)/UV/H(2)O(2)/Fe(II)) was attempted to degrade efficiently two fluoroquinolone drugs ENR [enrofloxacin (1-Cyclopropyl-7-(4-ethyl-1-piperazinyl)-6-fluoro-1,4-dihydro-4-oxo-3-quinolonecarboxylic acid)] and CIP [ciprofloxacin (1-cyclopropyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-quinoline-3-carboxylic acid)] in aqueous solutions at a concentrations of 0.15 mM for each drug. The efficiency of the applied oxidation processes (AOPs) has been estimated by the conversion of the original substrate (X(ENR) and X(CIP)) and the reduction of chemical oxygen demand (COD), total organic carbon (TOC). Special emphasis was laid on the effect of varying reaction pH as well as of the applied oxidant doses on the observed reaction kinetics for each advanced oxidation processes. High degradation efficiencies, particularly in terms of rates of TOC and COD abatement, were obtained for photo-Fenton assisted ozonation [O(3)/UV/H(2)O(2)/Fe(II)], compared to other advanced oxidation processes. At pH 3 and 25°C best results for the degradation of both investigated drugs were achieved when 10 mM H(2)O(2), 0.5 mM Fe(II) and an initial dose of 8.5 mg L(-1) ozone were applied. In addition, the evolution of toxicity of the reaction mixtures for different AOPs has been studied by the bioluminescence test (LUMIStox 300).

  2. Application of advanced oxidation processes for the treatment of cyanide containing effluent.

    PubMed

    Kim, Y J; Qureshi, T I; Min, K S

    2003-10-01

    Batch experiments were carried out for the removal of cyanide in the effluent of plating industry by the application of advanced oxidation processes. Four systems with different modes of oxidation in combination of ultra violet (UV) light with hydrogen peroxide and/or ozone were investigated. Of all the applied systems, UV-light with two oxidants, i.e. O3 (32 mg min(-1)), and H2O2 (1.36 g l(-1)) was found successful in bringing down the amount of cyanide from 157.32 mg l(-1) to 1.0 mg l(-1), which is the limit set by the Ministry of Environment of Korea for cyanide-containing discharges. Other systems, however, could not bring the cyanide abatement to the targeted value even with higher dosage of oxidants and an extended period of reaction time. Regardless of the oxidation modes applied, all the heavy metal ions in the treated effluent were reduced to 90%. Ultra violet light with the combination of two oxidants had the economic preference over the other systems since a relatively lower dosage of UV-light (2484 W-S cm(-2)) was found effective at achieving the targeted level of cyanide removal.

  3. Treatment of yellow water by membrane separations and advanced oxidation methods.

    PubMed

    Lazarova, Z; Spendlingwimmer, R

    2008-01-01

    Comparative experimental study is performed on purification of yellow wastewaters separated and collected in solarCity, Linz, Austria. Three membrane methods (micro-, ultra-, and nano-filtration), and two advanced oxidations (gamma radiation and electrochemical oxidation) were applied. Best results concerning the removal of pharmaceuticals and hormones from urine by membrane separation were achieved using the membrane NF-200 (FilmTec). Pharmaceuticals (ibuprofen and diclofenac), and hormones (oestrone, beta-oestradiol, ethenyloestradiol, oestriol) were removed completely from urine. NF-separation also has some disadvantages: losses of urea, and lowering the conductivity in the product (permeate). The retentates (concentrates) received have to be treated further by oxidation to destroy the "problem" compounds. The results showed that electrochemical oxidation is more suitable than gamma radiation. Gamma-radiation with intensities higher than 10 kGy has to be applied for efficiently destroying of ibuprofen, and especially diclofenac. A high quantity of intermediate "problem" substances with oestrone structure was formed during the gamma oxidation of hormone containing urine samples. The electrochemical oxidation can be successfully applied for elimination of pharmaceuticals such as diclofenac, and hormones (oestrone, beta-oestradiol) from yellow wastewater without loss of urea (nitrogen fertiliser).

  4. Synergistic cooperation of PDI family members in peroxiredoxin 4-driven oxidative protein folding.

    PubMed

    Sato, Yoshimi; Kojima, Rieko; Okumura, Masaki; Hagiwara, Masatoshi; Masui, Shoji; Maegawa, Ken-ichi; Saiki, Masatoshi; Horibe, Tomohisa; Suzuki, Mamoru; Inaba, Kenji

    2013-01-01

    The mammalian endoplasmic reticulum (ER) harbors disulfide bond-generating enzymes, including Ero1α and peroxiredoxin 4 (Prx4), and nearly 20 members of the protein disulfide isomerase family (PDIs), which together constitute a suitable environment for oxidative protein folding. Here, we clarified the Prx4 preferential recognition of two PDI family proteins, P5 and ERp46, and the mode of interaction between Prx4 and P5 thioredoxin domain. Detailed analyses of oxidative folding catalyzed by the reconstituted Prx4-PDIs pathways demonstrated that, while P5 and ERp46 are dedicated to rapid, but promiscuous, disulfide introduction, PDI is an efficient proofreader of non-native disulfides. Remarkably, the Prx4-dependent formation of native disulfide bonds was accelerated when PDI was combined with ERp46 or P5, suggesting that PDIs work synergistically to increase the rate and fidelity of oxidative protein folding. Thus, the mammalian ER seems to contain highly systematized oxidative networks for the efficient production of large quantities of secretory proteins.

  5. Nitrite-Driven Nitrous Oxide Production Under Aerobic Soil Conditions: Kinetics and Biochemical Controls

    USDA-ARS?s Scientific Manuscript database

    Nitrite (NO2-) can accumulate during nitrification in soil following fertilizer application. While the role of NO2- as a substrate regulating nitrous oxide (N2O) production is recognized, kinetic data are not available that allow for estimating N2O production or soil-to-atmosphere fluxes as a functi...

  6. Direct Light-Driven Water Oxidation by a Ladder-Type Conjugated Polymer Photoanode

    PubMed Central

    2015-01-01

    A conjugated polymer known for high stability (poly[benzimidazobenzophenanthroline], coded as BBL) is examined as a photoanode for direct solar water oxidation. In aqueous electrolyte with a sacrificial hole acceptor (SO32–), photoelectrodes show a morphology-dependent performance. Films prepared by a dispersion-spray method with a nanostructured surface (feature size of ∼20 nm) gave photocurrents up to 0.23 ± 0.02 mA cm–2 at 1.23 VRHE under standard simulated solar illumination. Electrochemical impedance spectroscopy reveals a constant flat-band potential over a wide pH range at +0.31 VNHE. The solar water oxidation photocurrent with bare BBL electrodes is found to increase with increasing pH, and no evidence of semiconductor oxidation was observed over a 30 min testing time. Characterization of the photo-oxidation reaction suggests H2O2 or •OH production with the bare film, while functionalization of the interface with 1 nm of TiO2 followed by a nickel–cobalt catalyst gave solar photocurrents of 20–30 μA cm–2, corresponding with O2 evolution. Limitations to photocurrent production are discussed. PMID:26576469

  7. Mixed Molybdenum Oxides with Superior Performances as an Advanced Anode Material for Lithium-Ion Batteries

    PubMed Central

    Wu, Di; Shen, Rui; Yang, Rong; Ji, Wenxu; Jiang, Meng; Ding, Weiping; Peng, Luming

    2017-01-01

    A simple and effective carbon-free strategy is carried out to prepare mixed molybdenum oxides as an advanced anode material for lithium-ion batteries. The new material shows a high specific capacity up to 930.6 mAh·g−1, long cycle-life (>200 cycles) and high rate capability. 1D and 2D solid-state NMR, as well as XRD data on lithiated sample (after discharge) show that the material is associated with both insertion/extraction and conversion reaction mechanisms for lithium storage. The well mixed molybdenum oxides at the microscale and the involvement of both mechanisms are considered as the key to the better electrochemical properties. The strategy can be applied to other transition metal oxides to enhance their performance as electrode materials. PMID:28294179

  8. Mixed Molybdenum Oxides with Superior Performances as an Advanced Anode Material for Lithium-Ion Batteries.

    PubMed

    Wu, Di; Shen, Rui; Yang, Rong; Ji, Wenxu; Jiang, Meng; Ding, Weiping; Peng, Luming

    2017-03-15

    A simple and effective carbon-free strategy is carried out to prepare mixed molybdenum oxides as an advanced anode material for lithium-ion batteries. The new material shows a high specific capacity up to 930.6 mAh·g(-1), long cycle-life (>200 cycles) and high rate capability. 1D and 2D solid-state NMR, as well as XRD data on lithiated sample (after discharge) show that the material is associated with both insertion/extraction and conversion reaction mechanisms for lithium storage. The well mixed molybdenum oxides at the microscale and the involvement of both mechanisms are considered as the key to the better electrochemical properties. The strategy can be applied to other transition metal oxides to enhance their performance as electrode materials.

  9. Degradation of chelating agents in aqueous solution using advanced oxidation process (AOP).

    PubMed

    Sillanpää, Mika E T; Kurniawan, Tonni Agustiono; Lo, Wai-hung

    2011-06-01

    This article presents an overview with critical analysis of technical applicability of advanced oxidation process (AOP) in removing chelating agents from aqueous solution. Apart from the effect of metals for chelating agents as a major influencing factor, selected information such as pH, oxidant's dose, concentrations of pollutants and treatment performance is presented. The performance of individual AOP is compared. It is evident from our literature survey that photocatalysis with UV irradiation alone or coupled with TiO(2), ozonation and Fenton's oxidation are frequently applied to mineralize target pollutants. Overall, the selection of the most suitable AOP depends on the characteristics of effluents, technical applicability, discharge standard, regulatory requirements and environmental impacts.

  10. Regeneration of siloxane-exhausted activated carbon by advanced oxidation processes.

    PubMed

    Cabrera-Codony, Alba; Gonzalez-Olmos, Rafael; Martín, Maria J

    2015-03-21

    In the context of the biogas upgrading, siloxane exhausted activated carbons need to be regenerated in order to avoid them becoming a residue. In this work, two commercial activate carbons which were proved to be efficient in the removal of octamethylcyclotetrasiloxane (D4) from biogas, have been regenerated through advanced oxidation processes using both O3 and H2O2. After the treatment with O3, the activated carbon recovered up to 40% of the original adsorption capacity while by the oxidation with H2O2 the regeneration efficiency achieved was up to 45%. In order to enhance the H2O2 oxidation, activated carbon was amended with iron. In this case, the regeneration efficiency increased up to 92%.

  11. Mixed Molybdenum Oxides with Superior Performances as an Advanced Anode Material for Lithium-Ion Batteries

    NASA Astrophysics Data System (ADS)

    Wu, Di; Shen, Rui; Yang, Rong; Ji, Wenxu; Jiang, Meng; Ding, Weiping; Peng, Luming

    2017-03-01

    A simple and effective carbon-free strategy is carried out to prepare mixed molybdenum oxides as an advanced anode material for lithium-ion batteries. The new material shows a high specific capacity up to 930.6 mAh·g‑1, long cycle-life (>200 cycles) and high rate capability. 1D and 2D solid-state NMR, as well as XRD data on lithiated sample (after discharge) show that the material is associated with both insertion/extraction and conversion reaction mechanisms for lithium storage. The well mixed molybdenum oxides at the microscale and the involvement of both mechanisms are considered as the key to the better electrochemical properties. The strategy can be applied to other transition metal oxides to enhance their performance as electrode materials.

  12. Steam Oxidation Behavior of Advanced Steels and Ni-Based Alloys at 800 °C

    NASA Astrophysics Data System (ADS)

    Dudziak, T.; Boroń, L.; Deodeshmukh, V.; Sobczak, J.; Sobczak, N.; Witkowska, M.; Ratuszek, W.; Chruściel, K.

    2017-02-01

    This publication studies the steam oxidation behavior of advanced steels (309S, 310S and HR3C) and Ni-based alloys (Haynes® 230®, alloy 263, alloy 617 and Haynes® 282®) exposed at 800 °C for 2000 h under 1 bar pressure, in a pure water steam system. The results revealed that all exposed materials showed relatively low weight gain, with no spallation of the oxide scale within the 2000 h of exposure. XRD analysis showed that Ni-based alloys developed an oxide scale consisting of four main phases: Cr2O3 (alloy 617, Haynes® 282®, alloy 263 and Haynes® 230®), MnCr2O4 (alloy 617, Haynes® 282® and Haynes® 230®), NiCr2O4 (alloy 617) and TiO2 (alloy 263, Haynes® 282®). In contrast, advanced steels showed the development of Cr2O3, MnCr2O4, Mn7SiO12, FeMn(SiO4) and SiO2 phases. The steel with the highest Cr content showed the formation of Fe3O4 and the thickest oxide scale.

  13. Steam Oxidation Behavior of Advanced Steels and Ni-Based Alloys at 800 °C

    NASA Astrophysics Data System (ADS)

    Dudziak, T.; Boroń, L.; Deodeshmukh, V.; Sobczak, J.; Sobczak, N.; Witkowska, M.; Ratuszek, W.; Chruściel, K.

    2017-03-01

    This publication studies the steam oxidation behavior of advanced steels (309S, 310S and HR3C) and Ni-based alloys (Haynes® 230®, alloy 263, alloy 617 and Haynes® 282®) exposed at 800 °C for 2000 h under 1 bar pressure, in a pure water steam system. The results revealed that all exposed materials showed relatively low weight gain, with no spallation of the oxide scale within the 2000 h of exposure. XRD analysis showed that Ni-based alloys developed an oxide scale consisting of four main phases: Cr2O3 (alloy 617, Haynes® 282®, alloy 263 and Haynes® 230®), MnCr2O4 (alloy 617, Haynes® 282® and Haynes® 230®), NiCr2O4 (alloy 617) and TiO2 (alloy 263, Haynes® 282®). In contrast, advanced steels showed the development of Cr2O3, MnCr2O4, Mn7SiO12, FeMn(SiO4) and SiO2 phases. The steel with the highest Cr content showed the formation of Fe3O4 and the thickest oxide scale.

  14. Advanced Oxide Material Systems for 1650 C Thermal/Environmental Barrier Coating Applications

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Fox, Dennis S.; Bansal, Narottam P.; Miller, Robert A.

    2004-01-01

    Advanced thermal and environmental barrier coatings (TEBCs) are being developed for low-emission SiC/SiC ceramic matrix composite (CMC) combustor and vane applications to extend the CMC liner and vane temperature capability to 1650 C (3000 F) in oxidizing and water-vapor-containing combustion environments. The advanced 1650 C TEBC system is required to have a better high-temperature stability, lower thermal conductivity, and more resistance to sintering and thermal stress than current coating systems under engine high-heat-flux and severe thermal cycling conditions. In this report, the thermal conductivity and water vapor stability of selected candidate hafnia-, pyrochlore- and magnetoplumbite-based TEBC materials are evaluated. The effects of dopants on the materials properties are also discussed. The test results have been used to downselect the TEBC materials and help demonstrate the feasibility of advanced 1650 C coatings with long-term thermal cycling durability.

  15. Sub-100 fJ and sub-nanosecond thermally driven threshold switching in niobium oxide crosspoint nanodevices.

    PubMed

    Pickett, Matthew D; Williams, R Stanley

    2012-06-01

    We built and measured the dynamical current versus time behavior of nanoscale niobium oxide crosspoint devices which exhibited threshold switching (current-controlled negative differential resistance). The switching speeds of 110 × 110 nm(2) devices were found to be Δt(ON) = 700 ps and Δt(OFF) = 2:3 ns while the switching energies were of the order of 100 fJ. We derived a new dynamical model based on the Joule heating rate of a thermally driven insulator-to-metal phase transition that accurately reproduced the experimental results, and employed the model to estimate the switching time and energy scaling behavior of such devices down to the 10 nm scale. These results indicate that threshold switches could be of practical interest in hybrid CMOS nanoelectronic circuits.

  16. Glucosamine prevents in vitro collagen degradation in chondrocytes by inhibiting advanced lipoxidation reactions and protein oxidation

    PubMed Central

    Tiku, Moti L; Narla, Haritha; Jain, Mohit; Yalamanchili, Praveen

    2007-01-01

    Osteoarthritis (OA) affects a large segment of the aging population and is a major cause of pain and disability. At present, there is no specific treatment available to prevent or retard the cartilage destruction that occurs in OA. Recently, glucosamine sulfate has received attention as a putative agent that may retard cartilage degradation in OA. The precise mechanism of action of glucosamine is not known. We investigated the effect of glucosamine in an in vitro model of cartilage collagen degradation in which collagen degradation induced by activated chondrocytes is mediated by lipid peroxidation reaction. Lipid peroxidation in chondrocytes was measured by conjugated diene formation. Protein oxidation and aldehydic adduct formation were studied by immunoblot assays. Antioxidant effect of glucosamine was also tested on malondialdehyde (thiobarbituric acid-reactive substances [TBARS]) formation on purified lipoprotein oxidation for comparison. Glucosamine sulfate and glucosamine hydrochloride in millimolar (0.1 to 50) concentrations specifically and significantly inhibited collagen degradation induced by calcium ionophore-activated chondrocytes. Glucosamine hydrochloride did not inhibit lipid peroxidation reaction in either activated chondrocytes or in copper-induced oxidation of purified lipoproteins as measured by conjugated diene formation. Glucosamine hydrochloride, in a dose-dependent manner, inhibited malondialdehyde (TBARS) formation by oxidized lipoproteins. Moreover, we show that glucosamine hydrochloride prevents lipoprotein protein oxidation and inhibits malondialdehyde adduct formation in chondrocyte cell matrix, suggesting that it inhibits advanced lipoxidation reactions. Together, the data suggest that the mechanism of decreasing collagen degradation in this in vitro model system by glucosamine may be mediated by the inhibition of advanced lipoxidation reaction, preventing the oxidation and loss of collagen matrix from labeled chondrocyte matrix

  17. Complete cobalt recovery from lithium cobalt oxide in self-driven microbial fuel cell - Microbial electrolysis cell systems

    NASA Astrophysics Data System (ADS)

    Huang, Liping; Yao, Binglin; Wu, Dan; Quan, Xie

    2014-08-01

    Complete cobalt recovery from lithium cobalt oxide requires to firstly leach cobalt from particles LiCoO2 and then recover cobalt from aqueous Co(II). A self-driven microbial fuel cell (MFC)-microbial electrolysis cell (MEC) system can completely carry out these two processes, in which Co(II) is firstly released from particles LiCoO2 on the cathodes of MFCs and then reduced on the cathodes of MECs which are powered by the cobalt leaching MFCs. A cobalt leaching rate of 46 ± 2 mg L-1 h-1 with yield of 1.5 ± 0.1 g Co g-1 COD (MFCs) and a Co(II) reduction rate of 7 ± 0 mg L-1 h-1 with yield of 0.8 ± 0.0 g Co g-1 COD (MECs), as well as a overall system cobalt yield of 0.15 ± 0.01 g Co g-1 Co can be achieved in this self-driven MFC-MEC system. Coulombic efficiencies reach 41 ± 1% (anodic MFCs), 75 ± 0% (anodic MECs), 100 ± 2% (cathodic MFCs), and 29 ± 1% (cathodic MECs) whereas overall system efficiency averages 34 ± 1%. These results provide a new process of linking MFCs to MECs for complete recovery of cobalt and recycle of spent lithium ion batteries with no external energy consumption.

  18. Photo-driven oxidation of water on α-Fe2O3 surfaces: An ab initio study

    NASA Astrophysics Data System (ADS)

    Nguyen, Manh-Thuong; Seriani, Nicola; Piccinin, Simone; Gebauer, Ralph

    2014-02-01

    Adopting the theoretical scheme developed by the Nørskov group [see, for example, Nørskov et al., J. Phys. Chem. B 108, 17886 (2004)], we conducted a density functional theory study of photo-driven oxidation processes of water on various terminations of the clean hematite (α-Fe2O3) (0001) surface, explicitly taking into account the strong correlation among the 3d states of iron through the Hubbard U parameter. Six best-known terminations, namely, Fe-Fe-O_3- (we call S_1), O-Fe-Fe- (S_2), O_2-Fe-Fe-(S_3), O_3-Fe-Fe- (S_4), Fe-O_3-Fe- (S_5), and O-Fe-O_3-(S_6), are first exposed to water, the stability of resulting surfaces is investigated under photoelectrochemical conditions by considering different chemical reactions (and their reaction free energies) that lead to surfaces covered by O atoms or/and OH groups. Assuming that the water splitting reaction is driven by the redox potential for photogenerated holes with respect to the normal hydrogen electrode, UVB, at voltage larger than UVB, most 3-oxygen terminated substrates are stable. These results thus suggest that the surface, hydroxylated in the dark, should release protons under illumination. Considering the surface free energy of all the possible terminations shows that O_3-S_5 and O_3-S_1 are the most thermodynamically stable. While water oxidation process on the former requires an overpotential of 1.22 V, only 0.84 V is needed on the latter.

  19. Photo-driven oxidation of water on α-Fe2O3 surfaces: an ab initio study.

    PubMed

    Nguyen, Manh-Thuong; Seriani, Nicola; Piccinin, Simone; Gebauer, Ralph

    2014-02-14

    Adopting the theoretical scheme developed by the Nørskov group [see, for example, Nørskov et al., J. Phys. Chem. B 108, 17886 (2004)], we conducted a density functional theory study of photo-driven oxidation processes of water on various terminations of the clean hematite (α-Fe2O3) (0001) surface, explicitly taking into account the strong correlation among the 3d states of iron through the Hubbard U parameter. Six best-known terminations, namely, Fe−Fe−O3− (we call S1), O−Fe−Fe−(S2), O2−Fe−Fe−(S3), O3−Fe−Fe− (S4), Fe−O3−Fe− (S5), and O−Fe−O3−(S6), are first exposed to water, the stability of resulting surfaces is investigated under photoelectrochemical conditions by considering different chemical reactions (and their reaction free energies) that lead to surfaces covered by O atoms or/and OH groups. Assuming that the water splitting reaction is driven by the redox potential for photogenerated holes with respect to the normal hydrogen electrode, UVB, at voltage larger than UVB, most 3-oxygen terminated substrates are stable. These results thus suggest that the surface, hydroxylated in the dark, should release protons under illumination. Considering the surface free energy of all the possible terminations shows that O3–S5 and O3–S1 are the most thermodynamically stable. While water oxidation process on the former requires an overpotential of 1.22 V, only 0.84 V is needed on the latter.

  20. Spin-orbit driven magnetic insulating state with Jeff=1/2 character in a 4d oxide

    DOE PAGES

    Calder, S.; Li, Ling; Okamoto, Satoshi; ...

    2015-11-30

    The unusual magnetic and electronic ground states of 5d iridates has been shown to be driven by intrinsically enhanced spin-orbit coupling (SOC). The influence of appreciable but reduced SOC in creating the manifested magnetic insulating states in 4d oxides is less clear, with one hurdle being the existence of such compounds. Here we present experimental and theoretical results on Sr4RhO6 that reveal SOC dominated behavior. Neutron measurements show the octahedra are both spatially separated and locally ideal, making the electronic ground state susceptible to alterations by SOC. Magnetic ordering is observed with a similar structure to an analogous Jeff=1/2 Mottmore » iridate. We consider the underlying role of SOC in this rhodate with density functional theory and x-ray absorption spectroscopy and find a magnetic insulating ground state with Jeff =1/2 character.The unusual magnetic and electronic ground states of 5d iridates have been shown to be driven by intrinsically enhanced spin-orbit coupling (SOC). The influence of appreciable but reduced SOC in creating the manifested magnetic insulating states in 4d oxides is less clear, with one hurdle being the existence of such compounds. Here, we present experimental and theoretical results on Sr4RhO6 that reveal SOC dominated behavior. Neutron measurements show the octahedra are both spatially separated and locally ideal, making the electronic ground state susceptible to alterations by SOC. Magnetic ordering is observed with a similar structure to an analogous Jeff=1/2 Mott iridate. We consider the underlying role of SOC in this rhodate with density functional theory and x-ray absorption spectroscopy, and find a magnetic insulating ground state with Jeff=12 character.« less

  1. Advanced Oxidation Protein Products and Carbonylated Proteins as Biomarkers of Oxidative Stress in Selected Atherosclerosis-Mediated Diseases.

    PubMed

    Gryszczyńska, Bogna; Formanowicz, Dorota; Budzyń, Magdalena; Wanic-Kossowska, Maria; Pawliczak, Elżbieta; Formanowicz, Piotr; Majewski, Wacław; Strzyżewski, Krzysztof Wojciech; Kasprzak, Magdalena P; Iskra, Maria

    2017-01-01

    The main question of this study was to evaluate the intensity of oxidative protein modification shown as advanced oxidation protein products (AOPP) and carbonylated proteins, expressed as protein carbonyl content (C=O) in abdominal aortic aneurysms (AAA), aortoiliac occlusive disease (AIOD), and chronic kidney disease (CKD). The study was carried out in a group of 35 AAA patients and 13 AIOD patients. However, CKD patients were divided into two groups: predialysis (PRE) included 50 patients or hemodialysis (HD) consisted of 34 patients. AOPP and C=O were measured using colorimetric assay kit, while C-reactive protein concentration was measured by high-sensitivity assay (hsCRP). The concentration of AOPP in both AAA and AIOD groups was higher than in PRE and HD groups according to descending order: AAA~AIOD > HD > PRE. The content of C=O was higher in the PRE group in comparison to AIOD and AAA according to the descending order: PRE~HD > AAA~AIOD. AAA, AIOD, and CKD-related atherosclerosis (PRE and HD) contribute to the changes in the formation of AOPP and C=O. They may promote modification of proteins in a different way, probably due to the various factors that influence oxidative stress here.

  2. Inhibitory actions of selected natural substances on formation of advanced glycation endproducts and advanced oxidation protein products.

    PubMed

    Grzebyk, Ewa; Piwowar, Agnieszka

    2016-09-29

    Advanced glycation endproducts (AGE) and advanced oxidation protein products (AOPP) arise as a result of excessive glycation and oxidation processes of proteins in hyperglycemia and oxidative stress conditions respectively, both in vivo and in vitro. In vivo these processes are especially intensified in patients with diabetes, and the adverse effects of AGE and AOPP are particularly unfavorable for the pathogenesis and aggravate the biochemical disturbances and clinical complications of diabetes. Total AGE and AOPP (T-AGE and T-AOPP) are heterogeneous groups of compounds, and they can be divided into two main fractions: high- and low-molecular-weight, i.e. HMW-AGE and HMW-AOPP as well as LMW-AGE and LMW-AOPP. Therefore it is important to find natural substances that will prevent formation of total AGE and AOPP and their high- and low-molecular-weight fractions and thereby reduce their adverse effects on tissues and organs. Selected natural substances and dietary supplements such as vitamin C, aminoguanidine, quercetin and green tea as well as the multicompound formulations Padma Circosan and Padma 28 were tested in an in vitro model using bovine serum albumin (BSA). Fluorescence of T-, HMW- and LMW-AGE and concentration of T-, HMW- and LMW-AOPP were measured after incubation with these substances. In the examined concentrations quercetin showed the greatest degree of inhibition for T-AGE (60.5 %) as well as for HMW-AGE (79.5 %), while in the case of LMW-AGE the greatest degree of glycation inhibition was shown by Padma Circosan (74.9 %). T-AOPP and HMW-AOPP were best inhibited by vitamin C (87.3 and 89.1 % respectively). The results obtained for LMW-AOPP are atypical, but the lowest concentration was observed in a sample with Padma 28. The results show that all tested natural compounds have inhibitory activity towards the formation of total and low- and high-molecular-weight forms of AGE and AOPP in vitro. That suggest a possible role in the prevention of

  3. A Turbine-Driven Ventilator Improves Adherence to Advanced Cardiac Life Support Guidelines During a Cardiopulmonary Resuscitation Simulation.

    PubMed

    Allen, Scott G; Brewer, Lara; Gillis, Erik S; Pace, Nathan L; Sakata, Derek J; Orr, Joseph A

    2017-09-01

    Research has shown that increased breathing frequency during cardiopulmonary resuscitation is inversely correlated with systolic blood pressure. Rescuers often hyperventilate during cardiopulmonary resuscitation (CPR). Current American Heart Association advanced cardiac life support recommends a ventilation rate of 8-10 breaths/min. We hypothesized that a small, turbine-driven ventilator would allow rescuers to adhere more closely to advanced cardiac life support (ACLS) guidelines. Twenty-four ACLS-certified health-care professionals were paired into groups of 2. Each team performed 4 randomized rounds of 2-min cycles of CPR on an intubated mannikin, with individuals altering between compressions and breaths. Two rounds of CPR were performed with a self-inflating bag, and 2 rounds were with the ventilator. The ventilator was set to deliver 8 breaths/min, pressure limit 22 cm H2O. Frequency, tidal volume (VT), peak inspiratory pressure, and compression interruptions (hands-off time) were recorded. Data were analyzed with a linear mixed model and Welch 2-sample t test. The median (interquartile range [IQR]) frequency with the ventilator was 7.98 (7.98-7.99) breaths/min. Median (IQR) frequency with the self-inflating bag was 9.5 (8.2-10.7) breaths/min. Median (IQR) ventilator VT was 0.5 (0.5-0.5) L. Median (IQR) self-inflating bag VT was 0.6 (0.5-0.7) L. Median (IQR) ventilator peak inspiratory pressure was 22 (22-22) cm H2O. Median (IQR) self-inflating bag peak inspiratory pressure was 30 (27-35) cm H2O. Mean ± SD hands-off times for ventilator and self-inflating bag were 5.25 ± 2.11 and 6.41 ± 1.45 s, respectively. When compared with a ventilator, volunteers ventilated with a self-inflating bag within ACLS guidelines. However, volunteers ventilated with increased variation, at higher VT levels, and at higher peak pressures with the self-inflating bag. Hands-off time was also significantly lower with the ventilator. (ClinicalTrials.gov registration NCT02743299

  4. An efficient bismuth tungstate visible-light-driven photocatalyst for breaking down nitric oxide.

    PubMed

    Li, Guisheng; Zhang, Dieqing; Yu, Jimmy C; Leung, Michael K H

    2010-06-01

    This paper reports a photocatalytic removal of 400 ppb level of NO in air under visible light irradiation by utilizing three-dimensional (3D) hierarchical bismuth tungstate (Bi(2)WO(6)) microspheres. A facile microwave-assisted hydrothermal method involving bismuth nitrate and sodium wolframate was developed to synthesize the photocatalyst. The Bi(2)WO(6) samples were characterized by using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Raman and ultraviolet-visible reflectance (UV-vis) spectroscopy. The relationship between the physicochemical property and the photocatalytic performance of the as prepared samples is discussed. The present work demonstrates that the 3D hierarchical Bi(2)WO(6) microspheres are effective visible-light-driven photocatalytic functional materials for air purification.

  5. Kinetics and Product Yields of the OH Driven Oxidation of Hydroxymethyl Hydroperoxide

    NASA Astrophysics Data System (ADS)

    Allen, H.; Teng, A.; Bates, K. H.; Crounse, J.; Thayer, M. P.; Rivera, J. C.; Keutsch, F. N.; St Clair, J. M.; Wennberg, P. O.

    2016-12-01

    Hydroperoxides play a significant role in altering the atmosphere's oxidative potential by acting as a sink and mobile reservoir of OH and odd oxygen species. Hydroxymethyl hydroperoxide (HMHP), formed primarily via the reaction of the C1 criegee with water, is among the most abundant organic peroxides in the atmosphere. Although reaction with OH is thought to represent one of the most important removal processes for HMHP, to date, no experimental study of HMHP and OH has been reported. Here, we present a laboratory study of the kinetics and product distributions formed in the reaction of HMHP with OH. Synthesized HMHP was oxidized by OH in an environmental chamber, and the decay of the hydroperoxide was monitored over time via CF3O- chemical ionization mass spectrometry (CIMS). Product yields, primarily formic acid and formaldehyde, were characterized by CIMS and by laser induced fluorescence (LIF). We use these measurements to interpret HMHP measurements obtained during SOAS and SEAC4RS. We further use global simulations with GEOS-Chem to evaluate the global importance of different HMHP sinks and the impact of HMHP oxidation on global formaldehyde and formic acid concentrations.

  6. The retina visual cycle is driven by cis retinol oxidation in the outer segments of cones.

    PubMed

    Sato, Shinya; Frederiksen, Rikard; Cornwall, M Carter; Kefalov, Vladimir J

    2017-01-01

    Vertebrate rod and cone photoreceptors require continuous supply of chromophore for regenerating their visual pigments after photoactivation. Cones, which mediate our daytime vision, demand a particularly rapid supply of 11-cis retinal chromophore in order to maintain their function in bright light. An important contribution to this process is thought to be the chromophore precursor 11-cis retinol, which is supplied to cones from Müller cells in the retina and subsequently oxidized to 11-cis retinal as part of the retina visual cycle. However, the molecular identity of the cis retinol oxidase in cones remains unclear. Here, as a first step in characterizing this enzymatic reaction, we sought to determine the subcellular localization of this activity in salamander red cones. We found that the onset of dark adaptation of isolated salamander red cones was substantially faster when exposing directly their outer vs. their inner segment to 9-cis retinol, an analogue of 11-cis retinol. In contrast, this difference was not observed when treating the outer vs. inner segment with 9-cis retinal, a chromophore analogue which can directly support pigment regeneration. These results suggest, surprisingly, that the cis-retinol oxidation occurs in the outer segments of cone photoreceptors. Confirming this notion, pigment regeneration with exogenously added 9-cis retinol was directly observed in the truncated outer segments of cones, but not in rods. We conclude that the enzymatic machinery required for the oxidation of recycled cis retinol as part of the retina visual cycle is present in the outer segments of cones.

  7. Online monitoring of Escherichia coli and Bacillus thuringiensis spore inactivation after advanced oxidation treatment.

    PubMed

    Sherchan, Samendra P; Snyder, Shane A; Gerba, Charles P; Pepper, Ian L

    2014-01-01

    Various studies have shown that advanced oxidation processes (AOPs) such as UV light in combination with hydrogen peroxide is an efficient process for the removal of a large variety of emerging contaminants including microorganisms. The mechanism of destruction in the presence of hydrogen peroxide (H2O2) is the enhanced formation of hydroxyl (·OH) radicals, which have a high oxidation potential. The goal of this study was to utilize in-line advanced oxidation to inactivate microbes, and document the inactivation via an in-line, real-time sensor. Escherichia coli cells and Bacillus thuringiensis spores were exposed to UV/H2O2 treatment in DI water, and the online sensor BioSentry(®) was evaluated for its potential to monitor inactivation in real-time. B. thuringiensis was selected as a non-pathogenic surrogate for B. anthracis, the causative agent of anthrax and a proven biological weapon. UV radiation and UV/H2O2 exposure resulted in a >6 log10 reduction of the viable culturable counts of E. coli vegetative cells, and a 3 log10 reduction of B. thuringiensis spores. Scanning electron microscopy of the treated samples revealed severe damage on the surface of most E. coli cells, yet there was no significant change observed in the morphology of the B. thuringiensis spores. Following AOP exposure, the BioSentry sensor showed an increase in the categories of unknown, rod and spores counts, but overall, did not correspond well with viable count assays. Data from this study show that advanced oxidation processes effectively inactivate E. coli vegetative cells, but not B. thuringiensis spores, which were more resistant to AOP. Further, the BioSentry in-line sensor was not successful in documenting destruction of the microbial cells in real-time.

  8. Enhancing hydrophilicity and water permeability of PET track-etched membranes by advanced oxidation process

    NASA Astrophysics Data System (ADS)

    Korolkov, Ilya V.; Mashentseva, Anastassiya A.; Güven, Olgun; Zdorovets, Maxim V.; Taltenov, Abzal A.

    2015-12-01

    In this study we present results on the application of advanced oxidation systems for effective and non-toxic oxidation of poly(ethylene terephthalate) track-etched membranes (PET TeMs) to improve their wettability and water transport properties. Two oxidizing systems: H2O2 under UV irradiation (H2O2/UV) and Fenton system under visible light (Fenton/H2O2/Vis) were compared. The surface of functionalized PET TeMs was characterized by using colorimetric assay, contact angle measurements and X-ray photoelectron spectroscopy (XPS). Results clearly showed that water permeability of PET TeMs treated with H2O2/UV was improved by 28 ± 5% compared with etched-only membrane, the same parameter was found to increase by 13 ± 4% in the case of Fenton/H2O2/Vis treatment. The proposed oxidation technique is very simple, environment friendly and not requiring special equipment or expensive chemicals. The surface hydrophilicity of the membranes stored for 360 days in air between paper sheets was analyzed by contact angle test, colorimetric assay to measure concentration of carboxylic groups on the surface with toluidine blue and XPS analysis. The hydrophilic properties of oxidized PET TeMs were found to be stable for a long period of time.

  9. New advanced surface modification technique: titanium oxide ceramic surface implants: long-term clinical results

    NASA Astrophysics Data System (ADS)

    Szabo, Gyorgy; Kovacs, Lajos; Barabas, Jozsef; Nemeth, Zsolt; Maironna, Carlo

    2001-11-01

    The purpose of this paper is to discuss the background to advanced surface modification technologies and to present a new technique, involving the formation of a titanium oxide ceramic coating, with relatively long-term results of its clinical utilization. Three general techniques are used to modify surfaces: the addition or removal of material and the change of material already present. Surface properties can also be changed without the addition or removal of material, through the laser or electron beam thermal treatment. The new technique outlined in this paper relates to the production of a corrosion-resistant 2000-2500 A thick, ceramic oxide layer with a coherent crystalline structure on the surface of titanium implants. The layer is grown electrochemically from the bulk of the metal and is modified by heat treatment. Such oxide ceramic-coated implants have a number of advantageous properties relative to implants covered with various other coatings: a higher external hardness, a greater force of adherence between the titanium and the oxide ceramic coating, a virtually perfect insulation between the organism and the metal (no possibility of metal allergy), etc. The coated implants were subjected to various physical, chemical, electronmicroscopic, etc. tests for a qualitative characterization. Finally, these implants (plates, screws for maxillofacial osteosynthesis and dental root implants) were applied in surgical practice for a period of 10 years. Tests and the experience acquired demonstrated the good properties of the titanium oxide ceramic-coated implants.

  10. Integration of advanced oxidation processes at mild conditions in wet scrubbers for odourous sulphur compounds treatment.

    PubMed

    Vega, Esther; Martin, Maria J; Gonzalez-Olmos, Rafael

    2014-08-01

    The effectiveness of different advanced oxidation processes on the treatment of a multicomponent aqueous solution containing ethyl mercaptan, dimethyl sulphide and dimethyl disulphide (0.5 mg L(-1) of each sulphur compound) was investigated with the objective to assess which one is the most suitable treatment to be coupled in wet scrubbers used in odour treatment facilities. UV/H2O2, Fenton, photo-Fenton and ozone treatments were tested at mild conditions and the oxidation efficiency obtained was compared. The oxidation tests were carried out in magnetically stirred cylindrical quartz reactors using the same molar concentration of oxidants (hydrogen peroxide or ozone). The results show that ozone and photo-Fenton are the most efficient treatments, achieving up to 95% of sulphur compounds oxidation and a mineralisation degree around 70% in 10 min. Furthermore, the total costs of the treatments taking into account the capital and operational costs were also estimated for a comparative purpose. The economic analysis revealed that the Fenton treatment is the most economical option to be integrated in a wet scrubber to remove volatile organic sulphur compounds, as long as there are no space constraints to install the required reactor volume. In the case of reactor volume limitation or retrofitting complexities, the ozone and photo-Fenton treatments should be considered as viable alternatives.

  11. Aging induces cardiac diastolic dysfunction, oxidative stress, accumulation of advanced glycation endproducts and protein modification.

    PubMed

    Li, Shi-Yan; Du, Min; Dolence, E Kurt; Fang, Cindy X; Mayer, Gabriele E; Ceylan-Isik, Asli F; LaCour, Karissa H; Yang, Xiaoping; Wilbert, Christopher J; Sreejayan, Nair; Ren, Jun

    2005-04-01

    Evidence suggests that aging, per se, is a major risk factor for cardiac dysfunction. Oxidative modification of cardiac proteins by non-enzymatic glycation, i.e. advanced glycation endproducts (AGEs), has been implicated as a causal factor in the aging process. This study was designed to examine the role of aging on cardiomyocyte contractile function, cardiac protein oxidation and oxidative modification. Mechanical properties were evaluated in ventricular myocytes from young (2-month) and aged (24-26-month) mice using a MyoCam system. The mechanical indices evaluated were peak shortening (PS), time-to-PS (TPS), time-to-90% relengthening (TR90) and maximal velocity of shortening/relengthening (+/- dL/dt). Oxidative stress and protein damage were evaluated by glutathione and glutathione disulfide (GSH/GSSG) ratio and protein carbonyl content, respectively. Activation of NAD(P)H oxidase was determined by immunoblotting. Aged myocytes displayed a larger cell cross-sectional area, prolonged TR90, and normal PS, +/- dL/dt and TPS compared with young myocytes. Aged myocytes were less tolerant of high stimulus frequency (from 0.1 to 5 Hz) compared with young myocytes. Oxidative stress and protein oxidative damage were both elevated in the aging group associated with significantly enhanced p47phox but not gp91phox expression. In addition, level of cardiac AGEs was approximately 2.5-fold higher in aged hearts than young ones determined by AGEs-ELISA. A group of proteins with a molecular range between 50 and 75 kDa with pI of 4-7 was distinctively modified in aged heart using one- or two-dimension SDS gel electrophoresis analysis. These data demonstrate cardiac diastolic dysfunction and reduced stress tolerance in aged cardiac myocytes, which may be associated with enhanced cardiac oxidative damage, level of AGEs and protein modification by AGEs.

  12. Hydrogen Oxidation-Driven Hot Electron Flow Detected by Catalytic Nanodiodes

    SciTech Connect

    Hervier, Antoine; Renzas, J. Russell; Park, Jeong Y.; Somorjai, Gabor A.

    2009-07-20

    Hydrogen oxidation on platinum is shown to be a surface catalytic chemical reaction that generates a steady state flux of hot (>1 eV) conduction electrons. These hot electrons are detected as a steady-state chemicurrent across Pt/TiO{sub 2} Schottky diodes whose Pt surface is exposed to hydrogen and oxygen. Kinetic studies establish that the chemicurrent is proportional to turnover frequency for temperatures ranging from 298 to 373 K for P{sub H2} between 1 and 8 Torr and P{sub O2} at 760 Torr. Both chemicurrent and turnover frequency exhibit a first order dependence on P{sub H2}.

  13. Closer to nature: an ATP-driven bioinspired catalytic oxidation process.

    PubMed

    Stefan, Loic; Duret, Damien; Spinelli, Nicolas; Defrancq, Eric; Monchaud, David

    2013-02-21

    The capability of DNA to acquire enzyme-like properties has led to the emergence of the so-called DNAzyme field; herein, we take a further leap along this nature-inspired road, demonstrating that a template assembled synthetic G-quartet (TASQ) can act as a pre-catalyst for catalytic peroxidase-mimicking oxidation reactions, whatever its nature (guanine or guanosine-based G-quartets), in an ATP-dependent manner, thereby bringing this bioinspired TASQzyme process even closer to nature.

  14. Determining oxidative and non-oxidative genotoxic effects driven by estuarine sediment contaminants on a human hepatoma cell line.

    PubMed

    Pinto, M; Costa, P M; Louro, H; Costa, M H; Lavinha, J; Caeiro, S; Silva, M J

    2014-04-15

    Estuarine sediments may be reservoirs of hydrophilic and hydrophobic pollutants, many of which are acknowledged genotoxicants, pro-mutagens and even potential carcinogens for humans. Still, studies aiming at narrowing the gap between ecological and human health risk of sediment-bound contaminant mixtures are scarce. Taking an impacted estuary as a case study (the Sado, SW Portugal), HepG2 (human hepatoma) cells were exposed in vitro for 48 h to extracts of sediments collected from two areas (urban/industrial and Triverine/agricultural), both contaminated by distinct mixtures of organic and inorganic toxicants, among which are found priority mutagens such as benzo[a]pyrene. Comparatively to a control test, extracts of sediments from both impacted areas produced deleterious effects in a dose-response manner. However, sediment extracts from the industrial area caused lower replication index plus higher cytotoxicity and genotoxicity (concerning total DNA strand breakage and clastogenesis), with emphasis on micronucleus induction. On the other hand, extracts from the rural area induced the highest oxidative damage to DNA, as revealed by the FPG (formamidopyrimidine-DNA glycosylase) enzyme in the Comet assay. Although the estuary, on its whole, has been classified as moderately contaminated, the results suggest that the sediments from the industrial area are significantly genotoxic and, furthermore, elicit permanent chromosome damage, thus potentially being more mutagenic than those from the rural area. The results are consistent with contamination by pro-mutagens like polycyclic aromatic hydrocarbons (PAHs), potentiated by metals. The sediments from the agriculture-influenced area likely owe their genotoxic effects to metals and other toxicants, probably pesticides and fertilizers, and able to induce reactive oxygen species without the formation of DNA strand breakage. The findings suggest that the mixtures of contaminants present in the assayed sediments are genotoxic

  15. Near infrared light-driven water oxidation in a molecule-based artificial photosynthetic device using an upconversion nano-photosensitizer.

    PubMed

    Liu, Xiaomin; Chen, Hung-Cheng; Kong, Xianggui; Zhang, Youlin; Tu, Langping; Chang, Yulei; Wu, Fei; Wang, Tongtong; Reek, Joost N H; Brouwer, Albert M; Zhang, Hong

    2015-08-21

    We provide the first demonstration of a near infrared light driven water oxidation reaction in a molecule-based artificial photosynthetic device using an upconversion nano-photosensitizer. One very attractive advantage of this system is that using NIR light irradiation does not cause significant photodamage, a serious problem in molecular based artificial photosynthesis under visible light irradiation.

  16. Recent advances in metal oxide-based electrode architecture design for electrochemical energy storage.

    PubMed

    Jiang, Jian; Li, Yuanyuan; Liu, Jinping; Huang, Xintang; Yuan, Changzhou; Lou, Xiong Wen David

    2012-10-02

    Metal oxide nanostructures are promising electrode materials for lithium-ion batteries and supercapacitors because of their high specific capacity/capacitance, typically 2-3 times higher than that of the carbon/graphite-based materials. However, their cycling stability and rate performance still can not meet the requirements of practical applications. It is therefore urgent to improve their overall device performance, which depends on not only the development of advanced electrode materials but also in a large part "how to design superior electrode architectures". In the article, we will review recent advances in strategies for advanced metal oxide-based hybrid nanostructure design, with the focus on the binder-free film/array electrodes. These binder-free electrodes, with the integration of unique merits of each component, can provide larger electrochemically active surface area, faster electron transport and superior ion diffusion, thus leading to substantially improved cycling and rate performance. Several recently emerged concepts of using ordered nanostructure arrays, synergetic core-shell structures, nanostructured current collectors, and flexible paper/textile electrodes will be highlighted, pointing out advantages and challenges where appropriate. Some future electrode design trends and directions are also discussed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Synthesis, characterization, and reactivity of dyad ruthenium-based molecules for light-driven oxidation catalysis.

    PubMed

    Farràs, Pau; Maji, Somnath; Benet-Buchholz, Jordi; Llobet, Antoni

    2013-05-27

    Dyad molecules containing the 2,3,5,6-tetrakis(2-pyridyl)pyrazine (tppz) ligand with general formula [(tpy)Ru(μ-tppz)Ru(X)(L-L)](n+) (X=Cl, CF3COO, or H2O; L-L=2,2'-bipyridine (bpy) or 3,5-bis(2-pyridyl)pyrazole (Hbpp); tpy=2,2':6',2"-terpyridine) have been prepared, purified, and isolated. The complexes have been characterized by analytical and spectroscopic techniques and by X-ray diffraction analysis for two of them. Additionally, full electrochemical characterization based on cyclic voltammetry, differential pulse voltammetry, and square wave voltammetry has been also performed. The pH dependence of the redox couples for the aqua complexes have also been studied and their corresponding Pourbaix diagrams drawn. Furthermore, their capacity to catalytically oxidize organic substrates, such as alcohols, alkenes, and sulfides, has been carried out chemically, electrochemically, and photochemically. Finally, their capacity to behave as water oxidation catalysts has also been tested. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Gold-TiO2-Nickel catalysts for low temperature-driven CO oxidation reaction

    NASA Astrophysics Data System (ADS)

    Hinojosa-Reyes, Mariana; Zanella, Rodolfo; Maturano-Rojas, Viridiana; Rodríguez-González, Vicente

    2016-04-01

    Nickel-doped-TiO2 catalysts were prepared by the sol-gel method and surface modified with gold nanoparticles (AuNPs) by the urea-deposition-precipitation technique. The as-synthesized catalysts were characterized by X-ray diffraction, Raman and XPS spectroscopies, N2 physisorption, STEM-HAADF microscopy and TPR hydrogen consumption. The Au/TiO2-Ni catalysts were evaluated catalytically performing CO oxidation reactions. The catalyst with nickel content of 1 wt. % (Au/TiO2-Ni 1) showed the highest CO conversion with respect to the high-nickel-content or bare/commercial TiO2 at 0 °C. In situ DRIFTS showed a strong participation of both nickel due to the presence of surface-nickel-metallic nanoparticles formed during the CO adsorption process at reaction temperatures above 200 °C, and surface-bridged-nickel-CO species. A minor deactivation rate was observed for the Au/TiO2-Ni 1 catalyst in comparison with the Au/TiO2 one. The oxygen vacancies that were created on the sol-gel-doped TiO2 improved the catalytic behavior during the performance of CO oxidation reactions, and inhibited the AuNP sintering.

  19. A solid oxide photoelectrochemical cell with UV light-driven oxygen storage in mixed conducting electrodes.

    PubMed

    Walch, Gregor; Rotter, Bernhard; Brunauer, Georg Christoph; Esmaeili, Esmaeil; Opitz, Alexander Karl; Kubicek, Markus; Summhammer, Johann; Ponweiser, Karl; Fleig, Jürgen

    2017-01-28

    A single crystalline SrTiO3 working electrode in a zirconia-based solid oxide electrochemical cell is illuminated by UV light at temperatures of 360-460 °C. In addition to photovoltaic effects, this leads to the build-up of a battery-type voltage up to more than 300 mV. After switching off UV light, this voltage only slowly decays. It is caused by UV-induced oxygen incorporation into the mixed conducting working electrode and thus by changes of the oxygen stoichiometry δ in SrTiO3-δ under UV illumination. These changes of the oxygen content could be followed in time-dependent voltage measurements and also manifest themselves in time-dependent resistance changes during and after UV illumination. Discharge currents measured after UV illumination reveal that a large fraction of the existing oxygen vacancies in SrTiO3 become filled under UV light. Additional measurements on cells with TiO2 thin film electrodes show the broader applicability of this novel approach for transforming light into chemical energy and thus the feasibility of solid oxide photoelectrochemical cells (SOPECs) in general and of a "light-charged oxygen battery" in particular.

  20. A solid oxide photoelectrochemical cell with UV light-driven oxygen storage in mixed conducting electrodes

    PubMed Central

    Walch, Gregor; Rotter, Bernhard; Brunauer, Georg Christoph; Esmaeili, Esmaeil; Opitz, Alexander Karl; Kubicek, Markus; Summhammer, Johann; Ponweiser, Karl

    2017-01-01

    A single crystalline SrTiO3 working electrode in a zirconia-based solid oxide electrochemical cell is illuminated by UV light at temperatures of 360–460 °C. In addition to photovoltaic effects, this leads to the build-up of a battery-type voltage up to more than 300 mV. After switching off UV light, this voltage only slowly decays. It is caused by UV-induced oxygen incorporation into the mixed conducting working electrode and thus by changes of the oxygen stoichiometry δ in SrTiO3–δ under UV illumination. These changes of the oxygen content could be followed in time-dependent voltage measurements and also manifest themselves in time-dependent resistance changes during and after UV illumination. Discharge currents measured after UV illumination reveal that a large fraction of the existing oxygen vacancies in SrTiO3 become filled under UV light. Additional measurements on cells with TiO2 thin film electrodes show the broader applicability of this novel approach for transforming light into chemical energy and thus the feasibility of solid oxide photoelectrochemical cells (SOPECs) in general and of a “light-charged oxygen battery” in particular. PMID:28261480

  1. Synthesis, characterization, and hierarchical organization of tungsten oxide nanorods: spreading driven by Marangoni flow.

    PubMed

    Yella, Aswani; Tahir, Muhammad Nawaz; Meuer, Stefan; Zentel, Rudolf; Berger, Rüdiger; Panthöfer, Martin; Tremel, Wolfgang

    2009-12-09

    Tungsten oxide nanorods were synthesized by a soft chemistry approach using tungsten alkoxide and trioctyl amine and oleic acid as the surfactants. The optical properties of the nanorods were studied. The nanorods were found to be soluble in a wide range of solvents like chloroform, cyclohexane, and so on. Upon solvent evaporation, the nanorods formed hierarchically organized solid state structures. Depending on the solvent used, the nanorods organized in different mesostructures. Moreover, the organization of the nanorods from mixtures of polar and nonpolar solvents was studied. Here, the Marangoni effect resulting from differences in the surface tensions of the two solvents was found to play a role in the organization of the nanorods. Furthermore, dip coating of the nanorod solutions on a mica substrate resulted in the formation of a uniform thin film of the nanorods, which may be useful for a variety of applications such as in electrochromic devices and in organic light emitting devices (OLEDs) using tungsten oxide as a buffer layer.

  2. Anaerobic methane oxidation driven by microbial reduction of natural organic matter in a tropical wetland.

    PubMed

    Valenzuela, Edgardo I; Prieto-Davó, Alejandra; López-Lozano, Nguyen E; Hernández-Eligio, Alberto; Vega-Alvarado, Leticia; Juárez, Katy; García-González, Ana Sarahí; López, Mercedes G; Cervantes, Francisco J

    2017-03-24

    Wetlands constitute the main natural source of methane on Earth due to their high content of natural organic matter (NOM), but key drivers such as electron acceptors supporting methanotrophic activities in these habitats are poorly understood. We performed anoxic incubations using freshly collected sediment along with water samples harvested from a tropical wetland, amended with (13)C-methane (0.67 atm) to test the capacity of its microbial community to perform anaerobic methane oxidation (AOM) linked to the reduction of the humic fraction of its NOM. Collected evidence demonstrates that electron-accepting functional groups (e.g. quinones) present in NOM fueled AOM by serving as terminal electron acceptor. Indeed, while sulfate reduction was the predominant process accounting for up to 42.5% of the AOM activities, microbial reduction of NOM concomitantly occurred. Furthermore, enrichment of wetland sediment with external NOM provided complementary electron-accepting capacity, which reduction accounted for ∼100 nmol (13)C-CH4 oxidized cm(-3) d(-1) Spectroscopic evidence showed that quinone moieties were heterogeneously distributed in the wetland sediment, and that their reduction occurred during the course of AOM. Moreover, an enrichment derived from wetland sediments performing AOM linked to NOM reduction stoichiometrically oxidized methane coupled to the reduction of the humic analogue, anthraquinone-2,6-disulfonate. Microbial populations potentially involved in AOM coupled to microbial reduction of NOM were dominated by divergent biota from putative AOM-associated archaea. We estimate that this microbial process could potentially contribute to the suppression of up to 114 Tg CH4 yr(-1) in coastal wetlands and more than 1,300 Tg yr(-1) considering the global wetland area.Importance Identifying key processes governing methane emissions from natural systems is of major importance considering the global warming effects triggered by this greenhouse gas. AOM coupled

  3. Unipolar assembly of zinc oxide rods manifesting polarity-driven collective luminescence

    PubMed Central

    Gautam, Ujjal K.; Imura, Masataka; Rout, Chandra Sekhar; Bando, Yoshio; Fang, Xiaosheng; Dierre, Benjamin; Sakharov, Leonid; Govindaraj, A.; Sekiguchi, Takashi; Golberg, Dmitri; Rao, C. N. R.

    2010-01-01

    Oriented assemblies of small crystals forming larger structures are common in nature and crucial for forthcoming technologies as they circumvent the difficulties of structural manipulation at microscopic scale. We have discovered two distinctive concentric assemblies of zinc oxide rods, wherein each rod has an intrinsically positive and a negative polar end induced by the noncentrosymmetric arrangement of Zn and O atoms. All the rods in a single assembly emanate out of a central core maintaining a single polar direction. Due to growth along the two polar surfaces with different atomic arrangements, these assemblies are distinct in their intrinsic properties and exhibit strong UV luminescence in the exterior of Zn-polar assemblies, unlike the O-polar assemblies. Although novel applications can be envisioned, these observations suggest that hierarchical organization with respect to internal asymmetry might be widespread in natural crystal assemblies. PMID:20643960

  4. High-temperature electromagnons in the magnetically induced multiferroic cupric oxide driven by intersublattice exchange.

    PubMed

    Jones, S P P; Gaw, S M; Doig, K I; Prabhakaran, D; Hétroy Wheeler, E M; Boothroyd, A T; Lloyd-Hughes, J

    2014-04-29

    Magnetically induced ferroelectric multiferroics present an exciting new paradigm in the design of multifunctional materials, by intimately coupling magnetic and polar order. Magnetoelectricity creates a novel quasiparticle excitation--the electromagnon--at terahertz frequencies, with spectral signatures that unveil important spin interactions. To date, electromagnons have been discovered at low temperature (<70 K) and predominantly in rare-earth compounds such as RMnO3. Here we demonstrate using terahertz time-domain spectroscopy that intersublattice exchange in the improper multiferroic cupric oxide (CuO) creates electromagnons at substantially elevated temperatures (213-230 K). Dynamic magnetoelectric coupling can therefore be achieved in materials, such as CuO, that exhibit minimal static cross-coupling. The electromagnon strength and energy track the static polarization, highlighting the importance of the underlying cycloidal spin structure. Polarized neutron scattering and terahertz spectroscopy identify a magnon in the antiferromagnetic ground state, with a temperature dependence that suggests a significant role for biquadratic exchange.

  5. Biodegradability of iopromide products after UV/H₂O₂ advanced oxidation.

    PubMed

    Keen, Olya S; Love, Nancy G; Aga, Diana S; Linden, Karl G

    2016-02-01

    Iopromide is an X-ray and MRI contrast agent that is virtually non-biodegradable and persistent through typical wastewater treatment processes. This study determined whether molecular transformation of iopromide in a UV/H2O2 advanced oxidation process (AOP) can result in biodegradable products. The experiments used iopromide labeled with carbon-14 on the aromatic ring to trace degradation of iopromide through UV/H2O2 advanced oxidation and subsequent biodegradation. The biotransformation assay tracked the formation of radiolabeled (14)CO2 which indicated full mineralization of the molecule. The results indicated that AOP formed biodegradable iopromide products. There was no (14)C released from the pre-AOP samples, but up to 20% of all radiolabeled carbon transformed into (14)CO2 over the course of 42 days of biodegradation after iopromide was exposed to advanced oxidation (compared to 10% transformation in inactivated post-AOP controls). In addition, the quantum yield of photolysis of iopromide was determined using low pressure (LP) and medium pressure (MP) mercury lamps as 0.069 ± 0.005 and 0.080 ± 0.007 respectively. The difference in the quantum yields for the two UV sources was not statistically significant at the 95% confidence interval (p = 0.08), which indicates the equivalency of using LP or MP UV sources for iopromide treatment. The reaction rate between iopromide and hydroxyl radicals was measured to be (2.5 ± 0.2) × 10(9) M(-1) s(-1). These results indicate that direct photolysis is a dominant degradation pathway in UV/H2O2 AOP treatment of iopromide. Other iodinated contrast media may also become biodegradable after exposure to UV or UV/H2O2.

  6. Advanced treatment of biologically pretreated coking wastewater by electrochemical oxidation using boron-doped diamond electrodes.

    PubMed

    Zhu, Xiuping; Ni, Jinren; Lai, Peng

    2009-09-01

    Electrochemical oxidation is a promising technology to treatment of bio-refractory wastewater. Coking wastewater contains high concentration of refractory and toxic compounds and the water quality usually cannot meet the discharge standards after conventional biological treatment processes. This paper initially investigated the electrochemical oxidation using boron-doped diamond (BDD) anode for advanced treatment of coking wastewater. Under the experimental conditions (current density 20-60mAcm(-2), pH 3-11, and temperature 20-60 degrees C) using BDD anode, complete mineralization of organic pollutants was almost achieved, and surplus ammonia-nitrogen (NH(3)-N) was further removed thoroughly when pH was not adjusted or at alkaline value. Moreover, the TOC and NH(3)-N removal rates in BDD anode cell were much greater than those in other common anode systems such as SnO(2) and PbO(2) anodes cells. Given the same target to meet the National Discharge Standard of China, the energy consumption of 64kWhkgCOD(-1) observed in BDD anode system was only about 60% as much as those observed in SnO(2) and PbO(2) anode systems. Further investigation revealed that, in BDD anode cell, organic pollutants were mainly degraded by reaction with free hydroxyl radicals and electrogenerated oxidants (S(2)O(8)(2-), H(2)O(2), and other oxidants) played a less important role, while direct electrochemical oxidation and indirect electrochemical oxidation mediated by active chlorine can be negligible. These results showed great potential of BDD anode system in engineering application as a final treatment of coking wastewater.

  7. Reduction of antibiotic resistance genes in municipal wastewater effluent by advanced oxidation processes.

    PubMed

    Zhang, Yingying; Zhuang, Yao; Geng, Jinju; Ren, Hongqiang; Xu, Ke; Ding, Lili

    2016-04-15

    This study investigated the reduction of antibiotic resistance genes (ARGs), intI1 and 16S rRNA genes, by advanced oxidation processes (AOPs), namely Fenton oxidation (Fe(2+)/H2O2) and UV/H2O2 process. The ARGs include sul1, tetX, and tetG from municipal wastewater effluent. The results indicated that the Fenton oxidation and UV/H2O2 process could reduce selected ARGs effectively. Oxidation by the Fenton process was slightly better than that of the UV/H2O2 method. Particularly, for the Fenton oxidation, under the optimal condition wherein Fe(2+)/H2O2 had a molar ratio of 0.1 and a H2O2 concentration of 0.01molL(-1) with a pH of 3.0 and reaction time of 2h, 2.58-3.79 logs of target genes were removed. Under the initial effluent pH condition (pH=7.0), the removal was 2.26-3.35 logs. For the UV/H2O2 process, when the pH was 3.5 with a H2O2 concentration of 0.01molL(-1) accompanied by 30min of UV irradiation, all ARGs could achieve a reduction of 2.8-3.5 logs, and 1.55-2.32 logs at a pH of 7.0. The Fenton oxidation and UV/H2O2 process followed the first-order reaction kinetic model. The removal of target genes was affected by many parameters, including initial Fe(2+)/H2O2 molar ratios, H2O2 concentration, solution pH, and reaction time. Among these factors, reagent concentrations and pH values are the most important factors during AOPs.

  8. Oxidative degradation of endotoxin by advanced oxidation process (O3/H2O2 & UV/H2O2).

    PubMed

    Oh, Byung-Taek; Seo, Young-Suk; Sudhakar, Dega; Choe, Ji-Hyun; Lee, Sang-Myeong; Park, Youn-Jong; Cho, Min

    2014-08-30

    The presence of endotoxin in water environments may pose a serious public health hazard. We investigated the effectiveness of advanced oxidative processes (AOP: O3/H2O2 and UV/H2O2) in the oxidative degradation of endotoxin. In addition, we measured the release of endotoxin from Escherichia coli following typical disinfection methods, such as chlorine, ozone alone and UV, and compared it with the use of AOPs. Finally, we tested the AOP-treated samples in their ability to induce tumor necrosis factor alpha (TNF-α) in mouse peritoneal macrophages. The production of hydroxyl radical in AOPs showed superior ability to degrade endotoxin in buffered solution, as well as water samples from Korean water treatment facilities, with the ozone/H2O2 being more efficient compared to UV/H2O2. In addition, the AOPs proved effective not only in eliminating E. coli in the samples, but also in endotoxin degradation, while the standard disinfection methods lead to the release of endotoxin following the bacteria destruction. Furthermore, in the experiments with macrophages, the AOPs-deactivated endotoxin lead to the smallest induction of TNF-α, which shows the loss of inflammation activity, compared to ozone treatment alone. In conclusion, these results suggest that AOPs offer an effective and mild method for endotoxin degradation in the water systems.

  9. Optimisation of an Advanced Oxidation Protein Products Assay: Its Application to Studies of Oxidative Stress in Diabetes Mellitus

    PubMed Central

    Taylor, Emma L.; Armstrong, Kenneth R.; Perrett, David; Hattersley, Andrew T.; Winyard, Paul G.

    2015-01-01

    Advanced oxidation protein products (AOPP) are reportedly elevated in the plasma of patients with a number of diseases, including diabetes mellitus, that involve oxidative stress. However, the accurate measurement of AOPP in human plasma is hampered by the formation of a precipitate following the addition of potassium iodide and glacial acetic acid according to the published assay procedure. Here we describe a modification of the AOPP assay which eliminates interference by precipitation and provides a robust, reliable, and reproducible protocol for the measurement of iodide oxidising capacity in plasma samples (intra-assay CV 1.7–5.3%, interassay CV 5.3–10.5%). The improved method revealed a significant association of AOPP levels with age (p < 0.05) and hypertension (p = 0.01) in EDTA-anticoagulated plasma samples from 52 patients with diabetes and 38 nondiabetic control subjects, suggesting a possible link between plasma oxidising capacity and endothelial and/or vascular dysfunction. There was no significant difference between AOPP concentrations in diabetic (74.8 ± 7.2 μM chloramine T equivalents) and nondiabetic (75.5 ± 7.0 μM chloramine T equivalents) individuals. PMID:26113954

  10. Post-treatment of reclaimed waste water based on an electrochemical advanced oxidation process

    NASA Technical Reports Server (NTRS)

    Verostko, Charles E.; Murphy, Oliver J.; Hitchens, G. D.; Salinas, Carlos E.; Rogers, Tom D.

    1992-01-01

    The purification of reclaimed water is essential to water reclamation technology life-support systems in lunar/Mars habitats. An electrochemical UV reactor is being developed which generates oxidants, operates at low temperatures, and requires no chemical expendables. The reactor is the basis for an advanced oxidation process in which electrochemically generated ozone and hydrogen peroxide are used in combination with ultraviolet light irradiation to produce hydroxyl radicals. Results from this process are presented which demonstrate concept feasibility for removal of organic impurities and disinfection of water for potable and hygiene reuse. Power, size requirements, Faradaic efficiency, and process reaction kinetics are discussed. At the completion of this development effort the reactor system will be installed in JSC's regenerative water recovery test facility for evaluation to compare this technique with other candidate processes.

  11. Post-treatment of reclaimed waste water based on an electrochemical advanced oxidation process

    NASA Technical Reports Server (NTRS)

    Verostko, Charles E.; Murphy, Oliver J.; Hitchens, G. D.; Salinas, Carlos E.; Rogers, Tom D.

    1992-01-01

    The purification of reclaimed water is essential to water reclamation technology life-support systems in lunar/Mars habitats. An electrochemical UV reactor is being developed which generates oxidants, operates at low temperatures, and requires no chemical expendables. The reactor is the basis for an advanced oxidation process in which electrochemically generated ozone and hydrogen peroxide are used in combination with ultraviolet light irradiation to produce hydroxyl radicals. Results from this process are presented which demonstrate concept feasibility for removal of organic impurities and disinfection of water for potable and hygiene reuse. Power, size requirements, Faradaic efficiency, and process reaction kinetics are discussed. At the completion of this development effort the reactor system will be installed in JSC's regenerative water recovery test facility for evaluation to compare this technique with other candidate processes.

  12. Advanced oxidation process using hydrogen peroxide/microwave system for solubilization of phosphate.

    PubMed

    Liao, Ping Huang; Wong, Wayne T; Lo, Kwang Victor

    2005-01-01

    An advanced oxidation process (AOP) combining hydrogen peroxide and microwave heating was used for the solubilization of phosphate from secondary municipal sludge from an enhanced biological phosphorus removal process. The microwave irradiation is used as a generator agent of oxidizing radicals as well as a heating source in the process. This AOP process could facilitate the release of a large amount of the sludge-bound phosphorus from the sewage sludge. More than 84% of the total phosphorous could be released at a microwave heating time of 5 min at 170 degrees C. This innovative process has the potential of being applied to simple sludge treatment processes in domestic wastewater treatment and to the recovery of phosphorus from the wastewater.

  13. Chemical and toxicological evaluation of transformation products during advanced oxidation processes.

    PubMed

    vom Eyser, C; Börgers, A; Richard, J; Dopp, E; Janzen, N; Bester, K; Tuerk, J

    2013-01-01

    The entry of pharmaceuticals into the water cycle from sewage treatment plants is of growing concern because environmental effects are evident at trace levels. Ozonation, UV- and UV/H(2)O(2)-treatment were tested as an additional step in waste water treatment because they have been proven to be effective in eliminating aqueous organic contaminants. The pharmaceuticals carbamazepine, ciprofloxacin, diclofenac, metoprolol and sulfamethoxazole as well as the personal care products galaxolide and tonalide were investigated in terms of degradation efficiency and by-product formation in consideration of toxic effects. The substances were largely removed from treatment plant effluent by ozonation, UV- and UV/H(2)O(2)-treatment. Transformation products were detected in all tested treatment processes. Accompanying analysis showed no genotoxic, cytotoxic or estrogenic potential for the investigated compounds after oxidative treatment of real waste waters. The results indicate that by-product formation from ozonation and advanced oxidation processes does not have any negative environmental impact.

  14. Comparison of various advanced oxidation processes for the degradation of phenylurea herbicides.

    PubMed

    Kovács, Krisztina; Farkas, János; Veréb, Gábor; Arany, Eszter; Simon, Gergő; Schrantz, Krisztina; Dombi, András; Hernádi, Klára; Alapi, Tünde

    2016-01-01

    Various types of advanced oxidation processes (AOPs), such as UV photolysis, ozonation, heterogeneous photocatalysis and their combinations were comparatively examined at the same energy input in a home-made reactor. The oxidative transformations of the phenylurea herbicides fenuron, monuron and diuron were investigated. The initial rates of transformation demonstrated that UV photolysis was highly efficient in the cases of diuron and monuron. Ozonation proved to be much more effective in the transformation of fenuron than in those of the chlorine containing monuron and diuron. In heterogeneous photocatalysis, the rate of decomposition decreased with increase of the number of chlorine atoms in the target molecule. Addition of ozone to UV-irradiated solutions and/or TiO2-containing suspensions markedly increased the initial rates of degradation. Dehalogenation of monuron and diuron showed that each of these procedures is suitable for the simultaneous removal of chlorinated pesticides and their chlorinated intermediates. Heterogeneous photocatalysis was found to be effective in the mineralization.

  15. Three-dimensional self-supported metal oxides for advanced energy storage.

    PubMed

    Ellis, Brian L; Knauth, Philippe; Djenizian, Thierry

    2014-06-04

    The miniaturization of power sources aimed at integration into micro- and nano-electronic devices is a big challenge. To ensure the future development of fully autonomous on-board systems, electrodes based on self-supported 3D nanostructured metal oxides have become increasingly important, and their impact is particularly significant when considering the miniaturization of energy storage systems. This review describes recent advances in the development of self-supported 3D nanostructured metal oxides as electrodes for innovative power sources, particularly Li-ion batteries and electrochemical supercapacitors. Current strategies for the design and morphology control of self-supported electrodes fabricated using template, lithography, anodization and self-organized solution techniques are outlined along with different efforts to improve the storage capacity, rate capability, and cyclability.

  16. Ozone catalysed with solids as an advanced oxidation process for landfill leachate treatment.

    PubMed

    Tizaoui, C; Mansouri, L; Bousselmi, L

    2007-01-01

    Heterogeneous catalytic ozonation (HCO) of wastewater is gaining both research and industrial interests. It is proved to be an advanced oxidation process since it involves hydroxyl radicals as oxidation species. Few studies have been carried out to test HCO in the treatment of landfill leachates. This work has been carried out to test three types of catalysts: activated carbon (AC), expanded perlite (EP) and titanium dioxide (TiO2) combined with ozone at 80 g/m3 gas concentration for the treatment of a leachate generated by Jebel Chakir landfill site near Tunis-capital of Tunisia. The work has shown a reduction in COD of about 45% and an increase in biodegradability (BOD5/COD) from 0.1 to 0.34. A catalyst concentration of 0.7 g/L was found optimal for the treatment of the leachate.

  17. Oxide semiconductor thin-film transistors: a review of recent advances.

    PubMed

    Fortunato, E; Barquinha, P; Martins, R

    2012-06-12

    Transparent electronics is today one of the most advanced topics for a wide range of device applications. The key components are wide bandgap semiconductors, where oxides of different origins play an important role, not only as passive component but also as active component, similar to what is observed in conventional semiconductors like silicon. Transparent electronics has gained special attention during the last few years and is today established as one of the most promising technologies for leading the next generation of flat panel display due to its excellent electronic performance. In this paper the recent progress in n- and p-type oxide based thin-film transistors (TFT) is reviewed, with special emphasis on solution-processed and p-type, and the major milestones already achieved with this emerging and very promising technology are summarizeed. After a short introduction where the main advantages of these semiconductors are presented, as well as the industry expectations, the beautiful history of TFTs is revisited, including the main landmarks in the last 80 years, finishing by referring to some papers that have played an important role in shaping transparent electronics. Then, an overview is presented of state of the art n-type TFTs processed by physical vapour deposition methods, and finally one of the most exciting, promising, and low cost but powerful technologies is discussed: solution-processed oxide TFTs. Moreover, a more detailed focus analysis will be given concerning p-type oxide TFTs, mainly centred on two of the most promising semiconductor candidates: copper oxide and tin oxide. The most recent data related to the production of complementary metal oxide semiconductor (CMOS) devices based on n- and p-type oxide TFT is also be presented. The last topic of this review is devoted to some emerging applications, finalizing with the main conclusions. Related work that originated at CENIMAT|I3N during the last six years is included in more detail, which

  18. Removal of PCBs in contaminated soils by means of chemical reduction and advanced oxidation processes.

    PubMed

    Rybnikova, V; Usman, M; Hanna, K

    2016-09-01

    Although the chemical reduction and advanced oxidation processes have been widely used individually, very few studies have assessed the combined reduction/oxidation approach for soil remediation. In the present study, experiments were performed in spiked sand and historically contaminated soil by using four synthetic nanoparticles (Fe(0), Fe/Ni, Fe3O4, Fe3 - x Ni x O4). These nanoparticles were tested firstly for reductive transformation of polychlorinated biphenyls (PCBs) and then employed as catalysts to promote chemical oxidation reactions (H2O2 or persulfate). Obtained results indicated that bimetallic nanoparticles Fe/Ni showed the highest efficiency in reduction of PCB28 and PCB118 in spiked sand (97 and 79 %, respectively), whereas magnetite (Fe3O4) exhibited a high catalytic stability during the combined reduction/oxidation approach. In chemical oxidation, persulfate showed higher PCB degradation extent than hydrogen peroxide. As expected, the degradation efficiency was found to be limited in historically contaminated soil, where only Fe(0) and Fe/Ni particles exhibited reductive capability towards PCBs (13 and 18 %). In oxidation step, the highest degradation extents were obtained in presence of Fe(0) and Fe/Ni (18-19 %). The increase in particle and oxidant doses improved the efficiency of treatment, but overall degradation extents did not exceed 30 %, suggesting that only a small part of PCBs in soil was available for reaction with catalyst and/or oxidant. The use of organic solvent or cyclodextrin to improve the PCB availability in soil did not enhance degradation efficiency, underscoring the strong impact of soil matrix. Moreover, a better PCB degradation was observed in sand spiked with extractable organic matter separated from contaminated soil. In contrast to fractions with higher particle size (250-500 and <500 μm), no PCB degradation was observed in the finest fraction (≤250 μm) having higher organic matter content. These findings

  19. Advanced Oxide Material Systems For 1650 C Thermal/Environmental Barrier Coating Applications

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Fox, Dennis S.; Bansal, Narottam P.; Miller, Robert A.

    2004-01-01

    Advanced thermal/environmental barrier coatings (T/EBCs) are being developed for low emission SiC/SiC ceramic matrix composite (CMC) combustor and vane applications to extend the CMC liner and vane temperature capability to 1650 C (3000 F) in oxidizing and water-vapor containing combustion environments. The 1650 C T/EBC system is required to have better thermal stability, lower thermal conductivity, and improved sintering and thermal stress resistance than current coating systems. In this paper, the thermal conductivity, water vapor stability and cyclic durability of selected candidate zirconia-/hafnia-, pyrochlore- and magnetoplumbite-based T/EBC materials are evaluated. The test results have been used to downselect the T/EBC coating materials, and help demonstrate advanced 1650OC coatings feasibility with long-term cyclic durability.

  20. Remediation of phenol, lignin and paper effluents by advanced oxidative processes.

    PubMed

    Peralta-Zamora, P; Wypych, F; Carneiro, L M; Vaz, S R

    2004-12-01

    The tremendous environmental impact of pulping and bleaching effluents and the relatively low efficiency of the current biological remediation processes represent one of the most important problems of the paper industry. In this work the efficiency of heterogeneous and homogeneous advanced oxidative processes was evaluated toward the degradation of model substrates (phenol and lignin) and the remediation of paper effluents. Best results were found by application of the UV-H2O2 system, with almost total discoloration of both pulping and bleaching effluents and typical COD removal higher than 60%, at reaction times of 120 min. In view of the reported results, and mainly on account of the simplicity of the UV-H2O2 system, shows good potential for the advanced process to remediation of recalcitrant effluents like those studied in this present work.

  1. Occurrence and Removal of Organic Micropollutants in Landfill Leachates Treated by Electrochemical Advanced Oxidation Processes.

    PubMed

    Oturan, Nihal; van Hullebusch, Eric D; Zhang, Hui; Mazeas, Laurent; Budzinski, Hélène; Le Menach, Karyn; Oturan, Mehmet A

    2015-10-20

    In recent years, electrochemical advanced oxidation processes have been shown to be an effective alternative for the removal of refractory organic compounds from water. This study is focused on the effective removal of recalcitrant organic matter (micropollutants, humic substances, etc.) present in municipal solid waste landfill leachates. A mixture of eight landfill leachates has been studied by the electro-Fenton process using a Pt or boron-doped diamond (BDD) anode and a carbon felt cathode or by the anodic oxidation process with a BDD anode. These processes exhibit great oxidation ability due to the in situ production of hydroxyl radicals ((•)OH), a highly powerful oxidizing species. Both electrochemical processes were shown to be efficient in the removal of dissolved total organic carbon (TOC) from landfill leachates. Regarding the electro-Fenton process, the replacement of the classical anode Pt by the anode BDD allows better performance in terms of dissolved TOC removal. The occurrence and removal yield of 19 polycyclic aromatic hydrocarbons, 15 volatile organic compounds, 7 alkylphenols, 7 polychlorobiphenyls, 5 organochlorine pesticides, and 2 polybrominated diphenyl ethers in landfill leachate were also investigated. Both electrochemical processes allow one to reach a quasicomplete removal (about 98%) of these organic micropollutants.

  2. Degradation of the commercial surfactant nonylphenol ethoxylate by advanced oxidation processes.

    PubMed

    da Silva, Salatiel Wohlmuth; Klauck, Cláudia Regina; Siqueira, Marco Antônio; Bernardes, Andréa Moura

    2015-01-23

    Four different oxidation process, namely direct photolysis (DP) and three advanced oxidation processes (heterogeneous photocatalysis - HP, eletrochemical oxidation - EO and photo-assisted electrochemical oxidation - PEO) were applied in the treatment of wastewater containing nonylphenol ethoxylate (NPnEO). The objective of this work was to determine which treatment would be the best option in terms of degradation of NPnEO without the subsequent generation of toxic compounds. In order to investigate the degradation of the surfactant, the processes were compared in terms of UV/Vis spectrum, mineralization (total organic carbon), reaction kinetics, energy efficiency and phytotoxicity. A solution containing NPnEO was prepared as a surrogate of the degreasing wastewater, was used in the processes. The results showed that the photo-assisted processes degrade the surfactant, producing biodegradable intermediates in the reaction. On the other hand, the electrochemical process influences the mineralization of the surfactant. The process of PEO carried out with a 250W lamp and a current density of 10mA/cm(2) showed the best results in terms of degradation, mineralization, reaction kinetics and energy consumption, in addition to not presenting phytotoxicity. Based on this information, this process can be a viable alternative for treating wastewater containing NPnEO, avoiding the contamination of water resources. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Degradation of herbicide 4-chlorophenoxyacetic acid by advanced electrochemical oxidation methods.

    PubMed

    Boye, Birame; Dieng, Momar M; Brillas, Enric

    2002-07-01

    The herbicide 4-chlorophenoxyacetic acid (4-CPA) has been degraded in aqueous medium by advanced electrochemical oxidation processes such as electro-Fenton and photoelectro-Fenton with UV light, using an undivided cell containing a Pt anode. In these environmentally clean methods, the main oxidant is the hydroxyl radical produced from Fenton's reaction between Fe2+ added to the medium and H2O2 electrogenerated from an 02-diffusion cathode. Solutions of a 4-CPA concentration <400 ppm within the pH range of 2.0-6.0 at 35 degrees C can be completely mineralized at low current by photoelectro-Fenton, while electro-Fenton leads to ca. 80% of mineralization. 4-CPA is much more slowly degraded by anodic oxidation in the absence and presence of electrogenerated H2O2. 4-Chlorophenol, 4-chlorocatechol, and hydroquinone are identified as aromatic intermediates by CG-MS and quantified by reverse-phase chromatography. Further oxidation of these chloroderivatives yields stable chloride ions. Generated carboxylic acids such as glycolic, glyoxylic, formic, malic, maleic, fumaric, and oxalic are followed by ion exclusion chromatography. The highest mineralization rate found for photoelectro-Fenton is accounted for by the fast photodecomposition of complexes of Fe3+ with such short-chain acids, mainly oxalic acid, under the action of UV light.

  4. Efficiency of advanced oxidation processes in lowering bisphenol A toxicity and oestrogenic activity in aqueous samples.

    PubMed

    Plahuta, Maja; Tišler, Tatjana; Toman, Mihael Jožef; Pintar, Albin

    2014-03-01

    Bisphenol A (BPA) is a well-known endocrine disruptor with adverse oestrogen-like effects eliciting adverse effects in humans and wildlife. For this reason it is necessary to set up an efficient removal of BPA from wastewaters, before they are discharged into surface waters. The aim of this study was to compare the efficiency of BPA removal from aqueous samples with photolytic, photocatalytic, and UV/H₂O₂ oxidation. BPA solutions were illuminated with different bulbs (halogen; 17 W UV, 254 nm; and 150 W UV, 365 nm) with or without the TiO₂ P-25 catalyst or H₂O₂ (to accelerate degradation). Acute toxicity and oestrogenic activity of treated samples were determined using luminescent bacteria (Vibrio fischeri), water fleas (Daphnia magna), zebrafish embryos (Danio rerio), and Yeast Estrogen Screen (YES) assay with genetically modified yeast Saccharomyces cerevisiae. The results confirmed that BPA is toxic and oestrogenically active. Chemical analysis showed a reduction of BPA levels after photolytic treatment and 100 % conversion of BPA by photocatalytic and UV/H₂O₂ oxidation. The toxicity and oestrogenic activity of BPA were largely reduced in photolytically treated samples. Photocatalytic oxidation, however, either did not reduce BPA toxic and oestrogenic effects or even increased them in comparison with the baseline, untreated BPA solution. Our findings suggest that chemical analysis is not sufficient to determine the efficiency of advanced oxidation processes in removing pollutants from water and needs to be complemented with biological tests.

  5. Recent advances in synthesis and surface modification of superparamagnetic iron oxide nanoparticles with silica

    NASA Astrophysics Data System (ADS)

    Sodipo, Bashiru Kayode; Aziz, Azlan Abdul

    2016-10-01

    Research on synthesis of superparamagnetic iron oxide nanoparticles (SPION) and its surface modification for biomedical applications is of intense interest. Due to superparamagnetic property of SPION, the nanoparticles have large magnetic susceptibility, single magnetic domain and controllable magnetic behaviour. However, owing to easy agglomeration of SPION, surface modification of the magnetic particles with biocompatible materials such as silica nanoparticle has gained much attention in the last decade. In this review, we present recent advances in synthesis of SPION and various routes of producing silica coated SPION.

  6. US-UK Collaboration on Fossil Energy Advanced Materials: Task 1—Steam Oxidation

    SciTech Connect

    Holcomb, Gordon R.; Tylczak, Joseph; Carney, Casey

    2016-04-19

    This presentation goes over the following from the US-UK collaboration on Fossil Energy Advanced Materials: Task 1, Steam Oxidation: US-led or co-led deliverables, Phase II products (US), 2011-present, Phase III products, Phase III Plan, an explanation of sCO2 compared with sH2O, an explanation of Ni-base Alloys, an explanation of 300 Series (18Cr-8Ni)/E-Brite, an explanation of the typical Microchannel HX Fabrication process, and an explanation of diffusion bonded Ni-base superalloys.

  7. Sono-bromination of aromatic compounds based on the ultrasonic advanced oxidation processes.

    PubMed

    Fujita, Mitsue; Lévêque, Jean-Marc; Komatsu, Naoki; Kimura, Takahide

    2015-11-01

    A novel, mild "sono-halogenation" of various aromatic compounds with potassium halide was investigated under ultrasound in a biphasic carbon tetrachloride/water medium. The feasibility study was first undertaken with the potassium bromide and then extended to chloride and iodide analogues. This methodology could be considered as a new expansion of the ultrasonic advanced oxidation processes (UAOPs) into a synthetic aspect as the developed methodology is linked to the sonolytic disappearance of carbon tetrachloride. Advantages of the present method are not only that the manipulation of the bromination is simple and green, but also that the halogenating agents used are readily available, inexpensive, and easy-handling.

  8. Monolithic solid oxide fuel cell technology advancement for coal-based power generation

    SciTech Connect

    Not Available

    1992-04-14

    The program is conducted by a team consisting of AiResearch Los Angeles Division of Allied-Signal Aerospace Company and Argonne National Laboratory (ANL). The objective of the program is to advance materials and fabrication methodologies to develop a monolithic solid oxide fuel cell (MSOFC) system capable of meeting performance, life, and cost goals for coal-based power generation. The program focuses on materials research and development, fabrication process development, cell/stack performance testing and characterization, cost and system analysis, and quality development.

  9. Combining Advanced Oxidation Processes: Assessment Of Process Additivity, Synergism, And Antagonism

    SciTech Connect

    Peters, Robert W.; Sharma, M.P.; Gbadebo Adewuyi, Yusuf

    2007-07-01

    This paper addresses the process interactions from combining integrated processes (such as advanced oxidation processes (AOPs), biological operations, air stripping, etc.). AOPs considered include: Fenton's reagent, ultraviolet light, titanium dioxide, ozone (O{sub 3}), hydrogen peroxide (H{sub 2}O{sub 2}), sonication/acoustic cavitation, among others. A critical review of the technical literature has been performed, and the data has been analyzed in terms of the processes being additive, synergistic, or antagonistic. Predictions based on the individual unit operations are made and compared against the behavior of the combined unit operations. The data reported in this paper focus primarily on treatment of petroleum hydrocarbons and chlorinated solvents. (authors)

  10. Treatment of statin compounds by advanced oxidation processes: Kinetic considerations and destruction mechanisms

    NASA Astrophysics Data System (ADS)

    Razavi, Behnaz; Song, Weihua; Santoke, Hanoz; Cooper, William J.

    2011-03-01

    This study examined the use of advanced oxidation/reduction processes (AO/RPs) for the destruction of cholesterol lowering statin pharmaceuticals. AO/RPs which utilize the oxidizing hydroxyl radical ( rad OH) and reducing aqueous electron (e -aq), to degrade chemical contaminants are alternatives to traditional water treatment methods, and are alternatives as water reuse becomes more generally implemented. Four major statin pharmaceuticals, fluvastatin, lovastatin, pravastatin and simvastatin, were studied, and the absolute bimolecular reaction rate constants with rad OH determined, (6.96±0.16)×10 9, (2.92±0.06)×10 9, (4.16±0.13)×10 9, and (3.13±0.15)×10 9 M -1 s -1, and for e -aq (2.31±0.06)×10 9, (0.45±0.01)×10 9, (1.26±0.01)×10 9, and (0.69±0.02)×10 9 M -1 s -1, respectively. To provide additional information on the radicals formed upon oxidation, transient spectra were measured and the overall reaction efficiency determined. Radical-based destruction mechanisms for destruction of the statins are proposed based on the LC-MS determination of the stable reaction by-products formed using 137Cs γ-irradiation of statin solutions. Knowing the reaction rates, reaction efficiencies and destruction mechanisms of these compounds is essential for the consideration of the use of advanced oxidation/reduction processes for the destruction of statins in aqueous systems.

  11. Controlling Magnetism in Spin-Orbit-Driven Oxides with Epitaxial Strain

    NASA Astrophysics Data System (ADS)

    Clancy, Patrick

    2015-03-01

    The layered perovskite iridates Sr2IrO4andBa2IrO4 are the prototypical spin-orbital Mott insulators, displaying a novel jeff = 1/2 ground state driven by strong 5d spin-orbit coupling effects. Efforts to understand, and ultimately control, this spin-orbit-induced ground state have led to a surge of interest in thin film iridates, which offer unique opportunities for the tuning of electronic and magnetic properties via epitaxial strain. We have performed complementary resonant magnetic x-ray scattering (RMXS) and resonant inelastic x-ray scattering (RIXS) measurements on epitaxial thin film samples of Sr2IrO4andBa2IrO4. By measuring 13 to 50 nm films grown on a variety of different substrates (PSO, GSO, STO, LSAT), we are able to investigate the impact of applied tensile and compressive strain on the magnetic structure, correlation lengths, and characteristic excitations of these materials. We find that the dispersion of the low-lying magnetic and orbital excitations is strongly affected by strain-induced structural changes, and show that epitaxial strain provides an effective method for tuning three distinct energy scales: the magnetic ordering temperature (TN) , the magnetic exchange interactions (J), and the non-cubic crystal field splitting (ΔCEF) . Perhaps most strikingly, we demonstrate that hard x-ray RIXS can be used to perform detailed magnetic dispersion measurements on thin film samples of 13 nm (~5 unit cells) or less. Work performed in collaboration with H. Gretarsson, A. Lupascu, J.A. Sears, Z. Nie, Y.-J. Kim (University of Toronto), Z. Islam, M.H. Upton, J. Kim, D. Casa, T. Gog, A.H. Said (Argonne National Laboratory), J. Nichols, J. Terzic, S.S.A. Seo, G. Cao (University of Kentucky), M. Uchida, D.G. Schlom, K.M. Shen (Cornell University), H. Stoll (University of Stuttgart), V.M. Katukuri, L.Hozoi, J. van den Brink (IFW Dresden).

  12. Biogenic concrete protection driven by the formate oxidation by Methylocystis parvus OBBP.

    PubMed

    Ganendra, Giovanni; Wang, Jianyun; Ramos, Jose A; Derluyn, Hannelore; Rahier, Hubert; Cnudde, Veerle; Ho, Adrian; Boon, Nico

    2015-01-01

    The effectiveness of Microbiologically Induced Carbonate Precipitation (MICP) from the formate oxidation by Methylocystis parvus OBBP as an alternative process for concrete protection was investigated. MICP was induced on Autoclaved Aerated Concrete (AAC), the model material, by immersing the material in 10(9) M. parvus cells mL(-1) containing 5 g L(-1) of calcium formate. A 2 days immersion of the material gave the maximum weight increase of the specimens (38 ± 19 mg) and this was likely due to the deposition of calcium carbonate, biomass, and unconverted calcium formate. The solid deposition mainly occurred in the micropores of the specimen, close to the outer surface. A significantly lower water absorption was observed in the bacterially treated specimens compared to the non-treated ones (up to 2.92 ± 0.91 kg m(-2)) and this could be attributed to the solid deposition. However, the sonication test demonstrated that the bacterial treatment did not give a consolidating effect to the material. Overall, compared to the currently employed urea hydrolysis process, the formate-based MICP by M. parvus offers a more environmentally friendly approach for the biotechnological application to protect concrete.

  13. Nonlocal Spin Diffusion Driven by Giant Spin Hall Effect at Oxide Heterointerfaces.

    PubMed

    Jin, Mi-Jin; Moon, Seon Young; Park, Jungmin; Modepalli, Vijayakumar; Jo, Junhyeon; Kim, Shin-Ik; Koo, Hyun Cheol; Min, Byoung-Chul; Lee, Hyun-Woo; Baek, Seung-Hyub; Yoo, Jung-Woo

    2017-01-11

    A two-dimensional electron gas emerged at a LaAlO3/SrTiO3 interface is an ideal system for "spin-orbitronics" as the structure itself strongly couple the spin and orbital degree of freedom through the Rashba spin-orbit interaction. One of core experiments toward this direction is the nonlocal spin transport measurement, which has remained elusive due to the low spin injection efficiency to this system. Here we bypass the problem by generating a spin current not through the spin injection from outside but instead through the inherent spin Hall effect and demonstrate the nonlocal spin transport. The analysis on the nonlocal spin voltage, confirmed by the signature of a Larmor spin precession and its length dependence, displays that both D'yakonov-Perel' and Elliott-Yafet mechanisms involve in the spin relaxation at low temperature. Our results show that the oxide heterointerface is highly efficient in spin-charge conversion with exceptionally strong spin Hall coefficient γ ∼ 0.15 ± 0.05 and could be an outstanding platform for the study of coupled charge and spin transport phenomena and their electronic applications.

  14. Are sperm capacitation and apoptosis the opposite ends of a continuum driven by oxidative stress?

    PubMed Central

    Aitken, Robert J; Baker, Mark A; Nixon, Brett

    2015-01-01

    This chapter explores the possibility that capacitation and apoptosis are linked processes joined by their common dependence on the continued generation of reactive oxygen species (ROS). According to this model capacitation is initiated in spematozoa following their release into the female reproductive tract as a consequence of intracellular ROS generation, which stimulates intracellular cAMP generation, inhibits tyrosine phosphatase activity and enhances the formation of oxysterols prior to their removal from the sperm surface by albumin. The continued generation of ROS by capacitating populations of spermatozoa eventually overwhelms the limited capacity of these cells to protect themselves from oxidative stress. As a result the over-capacitation of spermatozoa leads to a state of senescence and the activation of a truncated intrinsic apoptotic cascade characterized by enhanced mitochondrial ROS generation, lipid peroxidation, motility loss, caspase activation and phosphatidylserine externalization. The latter may be particularly important in instructing phagocytic leukocytes that the removal of senescent, moribund spermatozoa should be a silent process unaccompanied by the generation of proinflammatory cytokines. These observations reveal the central role played by redox chemistry in defining the life and death of spermatozoa. A knowledge of these mechanisms may help us to engineer novel solutions to both support and preserve the functionality of these highly specialized cells. PMID:25999358

  15. Biogenic concrete protection driven by the formate oxidation by Methylocystis parvus OBBP

    PubMed Central

    Ganendra, Giovanni; Wang, Jianyun; Ramos, Jose A.; Derluyn, Hannelore; Rahier, Hubert; Cnudde, Veerle; Ho, Adrian; Boon, Nico

    2015-01-01

    The effectiveness of Microbiologically Induced Carbonate Precipitation (MICP) from the formate oxidation by Methylocystis parvus OBBP as an alternative process for concrete protection was investigated. MICP was induced on Autoclaved Aerated Concrete (AAC), the model material, by immersing the material in 109 M. parvus cells mL−1 containing 5 g L−1 of calcium formate. A 2 days immersion of the material gave the maximum weight increase of the specimens (38 ± 19 mg) and this was likely due to the deposition of calcium carbonate, biomass, and unconverted calcium formate. The solid deposition mainly occurred in the micropores of the specimen, close to the outer surface. A significantly lower water absorption was observed in the bacterially treated specimens compared to the non-treated ones (up to 2.92 ± 0.91 kg m−2) and this could be attributed to the solid deposition. However, the sonication test demonstrated that the bacterial treatment did not give a consolidating effect to the material. Overall, compared to the currently employed urea hydrolysis process, the formate-based MICP by M. parvus offers a more environmentally friendly approach for the biotechnological application to protect concrete. PMID:26284061

  16. Are sperm capacitation and apoptosis the opposite ends of a continuum driven by oxidative stress?

    PubMed

    Aitken, Robert J; Baker, Mark A; Nixon, Brett

    2015-01-01

    This chapter explores the possibility that capacitation and apoptosis are linked processes joined by their common dependence on the continued generation of reactive oxygen species (ROS). According to this model capacitation is initiated in spematozoa following their release into the female reproductive tract as a consequence of intracellular ROS generation, which stimulates intracellular cAMP generation, inhibits tyrosine phosphatase activity and enhances the formation of oxysterols prior to their removal from the sperm surface by albumin. The continued generation of ROS by capacitating populations of spermatozoa eventually overwhelms the limited capacity of these cells to protect themselves from oxidative stress. As a result the over-capacitation of spermatozoa leads to a state of senescence and the activation of a truncated intrinsic apoptotic cascade characterized by enhanced mitochondrial ROS generation, lipid peroxidation, motility loss, caspase activation and phosphatidylserine externalization. The latter may be particularly important in instructing phagocytic leukocytes that the removal of senescent, moribund spermatozoa should be a silent process unaccompanied by the generation of proinflammatory cytokines. These observations reveal the central role played by redox chemistry in defining the life and death of spermatozoa. A knowledge of these mechanisms may help us to engineer novel solutions to both support and preserve the functionality of these highly specialized cells.

  17. BiVO(4)/CuWO(4) heterojunction photoanodes for efficient solar driven water oxidation.

    PubMed

    Pilli, Satyananda Kishore; Deutsch, Todd G; Furtak, Thomas E; Brown, Logan D; Turner, John A; Herring, Andrew M

    2013-03-07

    BiVO(4)/CuWO(4) heterojunction electrodes were prepared using spray deposition of a highly porous bismuth vanadate film onto the surface of an electrodeposited three dimensional network connected copper tungstate. Bilayer BiVO(4)/CuWO(4)/fluorine doped tin oxide glass (FTO) electrodes demonstrated higher photocurrent magnitudes than either with BiVO(4)/FTO or CuWO(4)/FTO electrodes in 1.0 M Na(2)SO(4) electrolyte buffered at pH 7. The photocurrent is enhanced by the formation of the heterojunction that aids charge carrier collection brought about by the band edge offsets. When the pH 7 buffered electrolytes contained 1.0 M bicarbonate is employed instead of 1.0 M sulfate, the charge transfer resistance was decreased. This led to nearly 1.8 times the photocurrent density at 1.0 V vs. Ag/AgCl. The photocurrent was stable over 24 hours in bicarbonate electrolyte.

  18. Towards highly efficient photoanodes: boosting sunlight-driven semiconductor nanomaterials for water oxidation.

    PubMed

    Gan, Jiayong; Lu, Xihong; Tong, Yexiang

    2014-07-07

    Harvesting energy directly from sunlight is a very attractive and desirable way to solve the rising energy demand. In the past few decades, considerable efforts have been focused on identifying appropriate materials and devices that can utilize solar energy to produce chemical fuels. Among these, one of the most promising options is the construction of a photoelectrochemical (PEC) cell that can produce hydrogen fuel or oxygen from water. Significant advancement in the understanding and construction of efficient photoanodes to improve performance has been accomplished within a short period of time owing to various newly developed ideas and approaches, including facilitating charge transportation in narrow band gap semiconductors or doping in wide band gap semiconductors for enhancing visible-light absorption; electrocatalysts for decreasing overpotentials; controlling the morphology of the materials for enhancing light absorption and shortening the transfer distance of minority carriers; and other methods such as using heterojunction structures for band-structure engineering, sensitization, and passivating layers. In this review, we focus on the recent developments of some promising visible-light active photoanode materials with high PEC performance, such as BiVO4, α-Fe2O3, WO3, TaON, and Ta3N5.

  19. WO3/W:BiVO4/BiVO4 graded photoabsorber electrode for enhanced photoelectrocatalytic solar light driven water oxidation.

    PubMed

    Choi, Junghyun; Sudhagar, Pitchaimuthu; Kim, Joo Hyun; Kwon, Jiseok; Kim, Jeonghyun; Terashima, Chiaki; Fujishima, Akira; Song, Taeseup; Paik, Ungyu

    2017-02-08

    We demonstrate the dual advantages of graded photoabsorbers in mesoporous metal oxide-based hetero interfacial photoanodes in improving photogenerated charge carrier (e(-)/h(+)) separation for the solar light-driven water-oxidation process. The pre-deposition of sol-gel-derived, tungsten-doped bismuth vanadate (W:BiVO4) onto a primary BiVO4 water oxidation layer forms graded interfaces, which facilitate charge transfer from the primary photoabsorber to the charge transport layer, thereby superseding the thickness-controlled charge recombination at the BiVO4 water oxidation catalyst. As a result, the WO3/BiVO4 hetero photoanode containing the photoactive W:BiVO4 interfacial layer showed 130% higher photocurrent than that of the interfacial layer-free hetero photoelectrode owing to the enhanced charge separation led water oxidation process.

  20. Assessment of the weather research and forecasting model generalized parameterization schemes for advancement of precipitation forecasting in monsoon-driven river basins

    NASA Astrophysics Data System (ADS)

    Sikder, Safat; Hossain, Faisal

    2016-09-01

    Some of the world's largest and flood-prone river basins experience a seasonal flood regime driven by the monsoon weather system. Highly populated river basins with extensive rain-fed agricultural productivity such as the Ganges, Indus, Brahmaputra, Irrawaddy, and Mekong are examples of monsoon-driven river basins. It is therefore appropriate to investigate how precipitation forecasts from numerical models can advance flood forecasting in these basins. In this study, the Weather Research and Forecasting model was used to evaluate downscaling of coarse-resolution global precipitation forecasts from a numerical weather prediction model. Sensitivity studies were conducted using the TOPSIS analysis to identify the likely best set of microphysics and cumulus parameterization schemes, and spatial resolution from a total set of 15 combinations. This identified best set can pinpoint specific parameterizations needing further development to advance flood forecasting in monsoon-dominated regimes. It was found that the Betts-Miller-Janjic cumulus parameterization scheme with WRF Single-Moment 5-class, WRF Single-Moment 6-class, and Thompson microphysics schemes exhibited the most skill in the Ganges-Brahmaputra-Meghna basins. Finer spatial resolution (3 km) without cumulus parameterization schemes did not yield significant improvements. The short-listed set of the likely best microphysics-cumulus parameterization configurations was found to also hold true for the Indus basin. The lesson learned from this study is that a common set of model parameterization and spatial resolution exists for monsoon-driven seasonal flood regimes at least in South Asian river basins.

  1. Advances in Instrumentation for Quantification of Isotopic Nitrous Oxide from ppb levels to 100%

    NASA Astrophysics Data System (ADS)

    Dong, F.; Gupta, M.; Leen, J.; Provencal, R. A.; Owano, T. G.; Baer, D. S.

    2013-12-01

    The isotopic composition of trace gases provides information of their origin and fate that cannot be determined from their concentration measurements alone. Biological source and loss processes, like bacterial production of nitrous oxide, are typically accompanied by isotopic selectivity associated with the kinetics of bond formation and destruction. Of the three important biologically mediated greenhouse gases (CO2, CH4 and N2O), the understanding of nitrous oxide isotopic budget in air lags behind the other two gases primarily due to the relatively low concentration of N2O in ambient air (~320 ppb). Furthermore, the origin of nitrates in rivers, lakes, ocean and other water supplies may be determined from analyses of isotopic nitrous oxide produced via chemical reduction or biological conversion. These processes can produce nitrous oxide at levels considerably greater than those present in ambient air. To date, analyses of isotopic nitrous oxide requires either pre-concentration of samples containing low concentrations or dilution of samples with high concentrations. We report significant advances of instrumentation for real-time measurements of site-specific isotopic nitrogen (δ15Nα, δ15Nβ, δ15N, δ18O) and mixing ratio [N2O] of nitrous oxide over a very wide range of mole fractions in air. Specifically, LGR's Isotopic N2O Analyzer can report site-specific isotopic nitrogen and isotopic oxygen continuously in flows ranging from 0.2 to over 20 ppm (parts per million) nitrous oxide in air (with preconcentration or dilution). Furthermore, for samples of limited volume, a batch technique may be used for similar isotopic measurements in discrete samples containing 0.2 ppm to 100% nitrous oxide (e.g., sample volumes from bacterial digestion can be as little as 1-10 mL). This novel technology, which employs cavity enhanced absorption spectroscopy (Off-Axis ICOS) and a mid-infrared laser (4.56 microns) and does not require any cryogenic components, has been

  2. Transformation products of pharmaceuticals in surface waters and wastewater formed during photolysis and advanced oxidation processes - degradation, elucidation of byproducts and assessment of their biological potency.

    PubMed

    Fatta-Kassinos, D; Vasquez, M I; Kümmerer, K

    2011-10-01

    The significance of transformation products of pharmaceuticals resulting from the parent compounds during natural and technical photolytic processes and advanced oxidation processes has only recently started to attract the interest of the scientific community. Even though relevant studies have now started to produce important knowledge, still many gaps exist that hinder the in-depth and broad understanding of the extent of the potential problems stemming from the presence of such compounds in the environment and the applicability of such techniques for wastewater and potable water treatment. The great diversity of pharmaceutical compounds, the variety of processes and conditions applied by the various research groups active in the field, and the endless list of potential biological endpoints that could potentially be explored, coupled with the limitations related to the analytical capabilities presently available, are some of the crucial parameters that characterize this challenging research direction. This review paper tries to highlight some of the most relevant studies performed so far and to summarize the parameters that prevent scientists from reaching comprehensive conclusions in relation to the formation, fate, and effects of transformation products of pharmaceutical compounds during photo-driven and advanced oxidation processes.

  3. Self-Powered Electrochemical Oxidation of 4-Aminoazobenzene Driven by a Triboelectric Nanogenerator.

    PubMed

    Gao, Shuyan; Su, Jingzhen; Wei, Xianjun; Wang, Miao; Tian, Miao; Jiang, Tao; Wang, Zhong Lin

    2017-01-24

    A rotary disc-structured triboelectric nanogenerator (rd-TENG) on the basis of free-standing electrification has been designed, where the aluminum composite panel has not been tailored to the stator becauseit is commercially available and cost-effective, has good electronic conductivity, and is easily processed. With the rotating speed increasing from 200 to 1000 rpm, the short-circuit current (Isc) is sharply enhanced from 50 μA to 200 μA, while the measured open-circuit voltage (Voc) and transferred charge (Qtr) almost keep constant, 600 V and 0.4 μC, respectively. The matched load for the rd-TENG at a rotating speed of 600 rpm is 2.7 MΩ, generating a maximum power of 19.75 mW, which corresponds to a maximum power density of 2.28 W m(-2). Using the electric power generated by such a rd-TENG, highly toxic and carcinogenic 4-aminoazobenzene can be selectively treated to produce CO2 or an oligomer via reasonably controlling electrochemical oxidation potentials. The underlying mechanism is tentatively proposed based on the cyclic voltammogram, gas chromatograph-mass spectrometer, electrochemical impedance spectroscopy, and UV-vis spectra. Here the electrochemical degradation in a single-compartment cell is more valid, preferable, and feasible. The output Voc and rectified current of rd-TENG guarantee its extensive application to self-power electrochemical degradation of other azo compounds, i.e., 2-(4-dimethylaminophenylazo) benzoic acid, to CO2. This work suggests that rd-TENG, sustainable energy, can be feasibly designed to self-power a practical electrochemical treatment of dyeing wastewater by harvesting vibration energy.

  4. Temperature-driven growth of reduced graphene oxide/copper nanocomposites for glucose sensing.

    PubMed

    Zhang, Qi; Wu, Zhong; Xu, Chen; Liu, Lei; Hu, Wenbin

    2016-12-09

    A one-spot method was developed for the synthesis of graphene sheet decorated with copper nanoparticles using different reduction temperatures via a molecular level mixing process. Here, we demonstrate that the reduction temperature is a crucial determinant of the properties of reduced graphene oxide (RGO)/metal composite and its electrocatalytic application in glucose sensing. To show this, we prepared a series of RGO/Cu composites at different reduction temperatures and examined the change rules of size, loading and dispersion of Cu particles, and the reduction extent of the RGO. Results showed that the Cu particle size increased with increasing reduction temperatures due to the Ostwald ripening process. Meanwhile, the Cu loading decreased with increasing reduction temperatures and the aggregation had not appeared in the high Cu loading situation. Additionally, the increasing reduction temperatures led to the decreasing concentrations of various oxygen-containing functional group of RGO with various degrees. The cyclic voltammogram showed that the RGO/metal composites fabricated under lower reduction temperatures exhibited higher electrocatalytic activity for glucose sensing, which was attributed to the higher surface area from larger loading of RGO/metal composites with smaller particle size. It can be concluded that the above factors play more significant roles in electrocatalytic efficiency than the decreased electron transfer rate between RGO and Cu within a certain range. These results highlight the importance of the reduction temperature influencing the properties of the RGO/metal composite and its application. We believe that these findings can be of great value in the further developing RGO/metal-based sensors for electrochemical detection of different analytes in emerging fields.

  5. Temperature-driven growth of reduced graphene oxide/copper nanocomposites for glucose sensing

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Wu, Zhong; Xu, Chen; Liu, Lei; Hu, Wenbin

    2016-12-01

    A one-spot method was developed for the synthesis of graphene sheet decorated with copper nanoparticles using different reduction temperatures via a molecular level mixing process. Here, we demonstrate that the reduction temperature is a crucial determinant of the properties of reduced graphene oxide (RGO)/metal composite and its electrocatalytic application in glucose sensing. To show this, we prepared a series of RGO/Cu composites at different reduction temperatures and examined the change rules of size, loading and dispersion of Cu particles, and the reduction extent of the RGO. Results showed that the Cu particle size increased with increasing reduction temperatures due to the Ostwald ripening process. Meanwhile, the Cu loading decreased with increasing reduction temperatures and the aggregation had not appeared in the high Cu loading situation. Additionally, the increasing reduction temperatures led to the decreasing concentrations of various oxygen-containing functional group of RGO with various degrees. The cyclic voltammogram showed that the RGO/metal composites fabricated under lower reduction temperatures exhibited higher electrocatalytic activity for glucose sensing, which was attributed to the higher surface area from larger loading of RGO/metal composites with smaller particle size. It can be concluded that the above factors play more significant roles in electrocatalytic efficiency than the decreased electron transfer rate between RGO and Cu within a certain range. These results highlight the importance of the reduction temperature influencing the properties of the RGO/metal composite and its application. We believe that these findings can be of great value in the further developing RGO/metal-based sensors for electrochemical detection of different analytes in emerging fields.

  6. Subarctic wintertime dissolved iron speciation driven by thermal constraints on Fe(II) oxidation, dissolved organic matter and stream reach

    NASA Astrophysics Data System (ADS)

    Morita, Yuichiroh; Yamagata, Kei; Oota, Atsuki; Ooki, Atsushi; Isoda, Yutaka; Kuma, Kenshi

    2017-10-01

    We studied the seasonal variations in Fe(II), Fe(III), humic-like dissolved organic matter (DOM), nitrate and nitrite (NO3 + NO2), and silicate (Si(OH)4) in river waters of three subarctic rivers flowing into Hakodate Bay in southwestern Hokkaido, Japan from May 2010 to February 2014. High Fe(II) concentrations were detected in winter at the sampling sites where the river bottom was comprised of sandy or silty sediment, primarily the lower and middle reaches of the rivers. Conversely, from early spring to late autumn Fe(II) levels were low or undetectable. We infer that soluble Fe(II) concentration in these subarctic river waters is driven by the balance between the influx of Fe(II) to the river and the Fe(II) oxidation rates that determines the dynamics in Fe(II) concentration in the river water. The Fe(II) may originate from reductive dissolution of Fe(III) in the river sediment or from Fe(II)-bearing groundwater. The latter seems to be the most likely source during winter time. The high Fe(II) concentrations during winter is predominantly attributed to the extremely slow oxidation rate of Fe(II) to Fe(III) at low water temperature rather than to an actual increase in the flux of reduced Fe(II). Nevertheless, we propose that the flux of reduced Fe(II) from river sediments and groundwater in lowland area of the catchment to overlying river waters might be the most important sources of iron in river waters. This provides an important insight into the role of river processes and the interaction between climate and river morphology in determining the inputs of iron to subarctic coastal marine waters.

  7. A summary and assessment of oxidation driven volatility experiments at the INEL and their application to fusion reactor safety assessments

    SciTech Connect

    McCarthy, K.A.; Smolik, G.R.; Harms, S.L.

    1994-09-01

    This report contains a summary and assessment of oxidation-driven volatility tests through March 1994 at the Idaho National Engineering Laboratory. Materials tested include a Cu alloy in air and steam, PCA stainless steel (similar to 316SS) in air and steam, AMCR-033 steel in air, HT-9 steel in air and steam, a Nb alloy in air and steam, a W alloy in air and steam, and two V alloys in air with a limited number of tests in steam. We give a brief description of the tests, including alloy compositions and test temperatures. For many materials, our results indicate that both volatility and oxide spalling are responsible for mobilizing mass, thus we refer to our measurements as mass flux or mobility flux. We plot mobility data for each element and present curve fits to the data. We include a section on how the mobility information is used in safety assessments. We calculate the early dose inventory of a first wall made of each material tested (the early dose to the maximum exposed individual that would result if all the material were mobilized and transported to the site boundary), and the early dose that would result when mobility fractions are considered in the calculation. We use this information to assess the data by determining which elements are the most important and concentrating on providing the mobility data for those elements. We discuss where more data are needed, and our plans for obtaining that data. Additionally, we discuss what must be done to produce a database that will withstand regulatory scrutiny.

  8. Cadmium sulfide quantum dots supported on gallium and indium oxide for visible-light-driven hydrogen evolution from water.

    PubMed

    Pan, Yun-xiang; Zhuang, Huaqiang; Hong, Jindui; Fang, Zheng; Liu, Hai; Liu, Bin; Huang, Yizhong; Xu, Rong

    2014-09-01

    In this work, CdS quantum dots (QDs) supported on Ga2O3 and In2O3 are applied for visible-light-driven H2 evolution from aqueous solutions that contain lactic acid. With Pt as the cocatalyst, the H2 evolution rates on CdS/Pt/Ga2O3 and CdS/Pt/In2O3 are as high as 995.8 and 1032.2 μmol h(-1), respectively, under visible light (λ>420 nm) with apparent quantum efficiencies of 43.6 and 45.3% obtained at 460 nm, respectively. These are much higher than those on Pt/CdS (108.09 μmol h(-1)), Pt/Ga2O3 (0.12 μmol h(-1)), and Pt/In2O3 (0.05 μmol h(-1)). The photocatalysts have been characterized thoroughly and their band structures and photocurrent responses have been measured. The band alignment between the CdS QDs and In2O3 can lead to interfacial charge separation, which cannot occur between the CdS QDs and Ga2O3. Among the various possible factors that contribute to the high H2 evolution rates on CdS/Pt/oxide, the surface properties of the metal oxides play important roles, which include (i) the anchoring of CdS QDs and Pt nanoparticles for favorable interactions and (ii) the efficient trapping of photogenerated electrons from the CdS QDs because of surface defects (such as oxygen defects) based on photoluminescence and photocurrent studies.

  9. Application of electrochemical advanced oxidation processes to the mineralization of the herbicide diuron.

    PubMed

    Pipi, Angelo R F; Sirés, Ignasi; De Andrade, Adalgisa R; Brillas, Enric

    2014-08-01

    Here, solutions with 0.185mM of the herbicide diuron of pH 3.0 have been treated by electrochemical advanced oxidation processes (EAOPs) like electrochemical oxidation with electrogenerated H2O2 (EO-H2O2), electro-Fenton (EF) and UVA photoelectro-Fenton (PEF) or solar PEF (SPEF). Trials were performed in stirred tank reactors of 100mL and in a recirculation flow plant of 2.5L using a filter-press reactor with a Pt or boron-doped diamond (BDD) anode and an air-diffusion cathode for H2O2 electrogeneration. Oxidant hydroxyl radicals were formed from water oxidation at the anode and/or in the bulk from Fenton's reaction between added Fe(2+) and generated H2O2. In both systems, the relative oxidation ability of the EAOPs increased in the sequence EO-H2O2

  10. Advanced oxidation processes coupled with electrocoagulation for the exhaustive abatement of Cr-EDTA.

    PubMed

    Durante, Christian; Cuscov, Marco; Isse, Abdirisak Ahmed; Sandonà, Giancarlo; Gennaro, Armando

    2011-02-01

    Using Cr-EDTA as a model system, a two-step method has been investigated for the abatement of persistent chromium complexes in water. The treatment consists of an oxidative decomposition of the organic ligands by means of ozonization or electrochemical oxidation at a boron doped diamond (BDD) electrode, followed by removal of the metal via electrochemical coagulation. In the designed synthetic waste, EDTA has been used both as a chelating agent and as a mimic of the organic content of a typical wastewater provided by a purification leather plant. A crucial point evaluated is the influence of the oxidative pretreatment on the chemical modification of the synthetic waste and hence on the electrocoagulation efficacy. Because of the great stability of Cr complexes, such as Cr-EDTA, the classical coagulation methods, based on ligand exchange between Cr(III) and Fe(II) or Fe(III), are ineffective toward Cr abatement in the presence of organic substances. On the contrary, when advanced oxidation processes (AOPs), such as ozonization or electrooxidation at a BDD anode are applied in series with electrocoagulation (EC), complete abatement of the recalcitrant Cr fraction can be achieved. ECs have been carried out by using Fe sacrificial anodes, with alternating polarization and complete Cr abatement (over 99%) has been obtained with modest charge consumption. It has been found that Cr(III) is first oxidized to Cr(VI) in the AOP preceding EC. Then, during EC, Cr(VI) is mainly reduced back to Cr(III) by electrogenerated Fe(II). Thus, Cr is mainly eliminated as Cr(III). However, a small fraction of Cr(VI) goes with the precipitate as confirmed by XPS analysis of the sludge.

  11. Association between advanced oxidation protein products and 5-year mortality risk among amazon riparian elderly population.

    PubMed

    Silva, T O; Jung, I E C; Moresco, R N; Barbisan, F; Ribeiro, E E; Ribeiro, E A M; Motta, K; Britto, E; Tasch, E; Bochi, G; Duarte, M M F; Oliveira, A R; Marcon, M; Belló, C; dos Santos Montagner, G F; da Cruz, I B M

    2015-02-01

    Proteins are important targets of several modifications caused by oxidative stress, leading to structural changes and consequently partial or total loss of their functions. The oxidized proteins include advanced oxidation protein products (AOPP) derived from oxidation-modified albumin, as well as fibrinogen and lipoproteins. An increase in AOPP levels indicates an oxidative stress state and the presence of coexisting inflammation. Several investigations have also suggested an association between high AOPP levels and aging-related diseases. However, the link between elevated AOPP levels and elderly mortality risk has not yet been investigated. Here, we report on a 5-year longitudinal study that investigated the potential association between AOPP levels and mortality using a population-based representative sample of riparian elders living in Brazilian Amazon region (Maués-AM). Age, sex, socioeconomic and cultural conditions, chronic morbidities, polypharmacy, and previous morbidities were also tested as potential confounders. The AOPP levels were measured in 540 (84.78%) individuals, all of whom were followed over a 5-year period in order to establish the mortality rate. Within this study period, 74 (13.7%) elders died and 466 (86.3%) survived. The AOPP levels were higher among the elders who died within the 5-year period (46.27 ± 40.6 mmol/L) compared with those who survived (36.79 ± 20.84 mmol/L) (p = 0.002). The analysis confirmed the link between high AOPP levels and mortality risk, independent of other intervenient factors. These results suggest that elevated AOPP levels could be used to predict mortality risk in elderly patients.

  12. Advanced oxidation protein products and their relationship with cardiovascular risk factors in young apparently healthy people.

    PubMed

    Villalpando Sánchez, Diana Carolina; Alvarez Aguilar, Cleto; Gómez García, Anel

    Advanced oxidation protein products (AOPPs) are used as a marker to estimate oxidative stress in plasma proteins. Oxidative stress is considered a factor of cardiovascular risk (CVRF) related to increased blood pressure, and dyslipidaemia. The aim of this study was to evaluate the association between plasma AOPPs and CVRF in apparently healthy young adults. A prospective cross-sectional study was conducted on 120 students of the Faculty of Chemical-Pharmacobiology of the UMSNH. Body mass index (BMI) and blood pressure were determined. A blood specimen was also collected to quantify AOPPs, glucose, total cholesterol, lipoproteins (high, low, and very low density), and triglycerides. Differences were observed in the groups with and without CVRF, with significant differences in BMI, waist, body fat (P<.05), and lipid profile (P<.0001). AOPPs were higher in the group of young people with three and four CVRF (F: 4.651; P=.002). A negatively correlation was found between AOPPs and LDL cholesterol (r=-0.364; P=.0001). It was observed that AOPPs concentrations are increased as CVRF increase in young adults. Thus, this could be considered an important risk factor, because their deposition in the atherosclerotic plaque favours the atherogenic process, and thus the development of cardiovascular disease. Quantification of AOPPs contributes to the indirect determination of oxidative status in the body. The study of metabolic and oxidative state of apparently healthy young adults is important in the prevention of cardiovascular disease in later life. More longitudinal studies are required to study its evolution. Copyright © 2017 Sociedad Española de Arteriosclerosis. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. Drinking water treatment of priority pesticides using low pressure UV photolysis and advanced oxidation processes.

    PubMed

    Sanches, Sandra; Barreto Crespo, Maria T; Pereira, Vanessa J

    2010-03-01

    This study reports the efficiency of low pressure UV photolysis for the degradation of pesticides identified as priority pollutants by the European Water Framework Directive 2000/60/EC. Direct low pressure UV photolysis and advanced oxidation processes (using hydrogen peroxide and titanium dioxide) experiments were conducted in laboratory grade water, surface water, and groundwater. LP direct photolysis using a high UV fluence (1500 mJ/cm(2)) was found to be extremely efficient to accomplish the degradation of all pesticides except isoproturon, whereas photolysis using hydrogen peroxide and titanium dioxide did not significantly enhance their removal. In all matrices tested the experimental photolysis of the pesticides followed the same trend: isoproturon degradation was negligible, alachlor, pentachlorophenol, and atrazine showed similar degradation rate constants, whereas diuron and chlorfenvinphos were highly removed. The degradation trend observed for the selected compounds followed the decadic molar absorption coefficients order with exception of isoproturon probably due to its extremely low quantum yield. Similar direct photolysis rate constants were obtained for each pesticide in the different matrices tested, showing that the water components did not significantly impact degradation. Extremely similar photolysis rate constants were also obtained in surface water for individual compounds when compared to mixtures. The model fluence and time-based rate constants reported were very similar to the direct photolysis experimental results obtained, while overestimating the advanced oxidation results. This model was used to predict how degradation of isoproturon, the most resilient compound, could be improved.

  14. Inactivation of adenovirus using low-dose UV/H2O2 advanced oxidation.

    PubMed

    Bounty, Sarah; Rodriguez, Roberto A; Linden, Karl G

    2012-12-01

    Adenovirus has consistently been observed to be the most resistant known pathogen to disinfection by ultraviolet light. This has had an impact on regulations set by the United States Environmental Protection Agency regarding the use of UV disinfection for virus inactivation in groundwater and surface water. In this study, enhancement of UV inactivation of adenovirus was evaluated when hydrogen peroxide was added to create an advanced oxidation process (AOP). While 4 log reduction of adenovirus was determined to require a UV dose (UV fluence) of about 200 mJ/cm(2) from a low pressure (LP) UV source (emitting at 253.7 nm), addition of 10 mg/L H(2)O(2) achieved 4 log inactivation at a dose of 120 mJ/cm(2). DNA damage was assessed using a novel nested PCR approach, and similar levels of DNA damage between the two different treatments were noted, suggesting the AOP enhancement in inactivation was not due to additional DNA damage. Hydroxyl radicals produced in the advanced oxidation process are likely able to damage parts of the virus not targeted by LPUV, such as attachment proteins, enhancing the UV-induced inactivation. The AOP-enhanced inactivation potential was modeled in three natural waters. This research sheds light on the inactivation mechanisms of viruses with ultraviolet light and in the presence of hydroxyl radicals and provides a practical means to enhance inactivation of this UV-resistant virus.

  15. Comparison of various advanced oxidation processes used in remediation of industrial wastewater laden with recalcitrant pollutants

    NASA Astrophysics Data System (ADS)

    Krishnan, S.; Rawindran, H.; Sinnathambi, C. M.; Lim, J. W.

    2017-06-01

    Due to the scarcity of water, it has become a necessity to improve the quality of wastewater that is discharged into the environment. Conventional wastewater treatment can be either a physical, chemical, and/or biological processes, or in some cases a combination of these operations. The main purpose of wastewater treatment is to eliminate nutrients, solids, and organic compounds from effluents. Current wastewater treatment technologies are deemed ineffective in the complete removal of pollutants, particularly organic matter. In many cases, these organic compounds are resistant to conventional treatment methods, thus creating the necessity for tertiary treatment. Advanced oxidation process (AOP), constitutes as a promising treatment technology for the management of wastewater. AOPs are characterised by a common chemical feature, where they utilize the highly reactive hydroxyl radicals for achieving complete mineralization of the organic pollutants into carbon dioxide and water. This paper delineates advanced oxidation processes currently used for the remediation of water and wastewater. It also provides the cost estimation of installing and running an AOP system. The costs are separated into three categories: capital, operational, and operating & maintenance.

  16. Fenton Reaction-Generated Advanced Oxidation Protein Products Induces Inflammation in Human Embryonic Kidney Cells.

    PubMed

    Bochi, Guilherme Vargas; Torbitz, Vanessa Dorneles; Santos, Roberto Christ Vianna; Cubillos-Rojas, Monica; López, José Luis Rosa; Siebel, Anna Maria; Gomes, Patrícia; de Oliveira, Jarbas Rodrigues; Moresco, Rafael Noal

    2016-08-01

    Fenton reaction is a new mechanism able to generate advanced oxidation protein products (AOPPs) by exposing the human serum albumin to the Fenton system. Here, we characterized the effects of Fenton reaction-generated advanced oxidation protein products (AOPP-FR) on the gene transcription of the nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2), and interleukin-6 (IL-6) in human embryonic kidney cells (HEK 293). To investigate the effects of AOPP-FR and AOPP-HOCl on transcription of inflammatory genes, the NF-κB, COX-2, and IL-6 luciferase promoter activities were analyzed. AOPP-FR and AOPP-HOCl were able to induce the activation of the gene transcription of NF-κB, COX-2, and IL-6 in HEK 293 cells. However, the effects of AOPP-FR were significantly higher than the effects of AOPP-HOCl in relation to COX-2 and IL-6. AOPP-FR induces the activation of the gene transcription of NF-κB, COX-2, and IL-6 and may represent a novel pathogenic mediator of inflammation in kidney.

  17. Analytical tools employed to determine pharmaceutical compounds in wastewaters after application of advanced oxidation processes.

    PubMed

    Afonso-Olivares, Cristina; Montesdeoca-Esponda, Sarah; Sosa-Ferrera, Zoraida; Santana-Rodríguez, José Juan

    2016-12-01

    Today, the presence of contaminants in the environment is a topic of interest for society in general and for the scientific community in particular. A very large amount of different chemical substances reaches the environment after passing through wastewater treatment plants without being eliminated. This is due to the inefficiency of conventional removal processes and the lack of government regulations. The list of compounds entering treatment plants is gradually becoming longer and more varied because most of these compounds come from pharmaceuticals, hormones or personal care products, which are increasingly used by modern society. As a result of this increase in compound variety, to address these emerging pollutants, the development of new and more efficient removal technologies is needed. Different advanced oxidation processes (AOPs), especially photochemical AOPs, have been proposed as supplements to traditional treatments for the elimination of pollutants, showing significant advantages over the use of conventional methods alone. This work aims to review the analytical methodologies employed for the analysis of pharmaceutical compounds from wastewater in studies in which advanced oxidation processes are applied. Due to the low concentrations of these substances in wastewater, mass spectrometry detectors are usually chosen to meet the low detection limits and identification power required. Specifically, time-of-flight detectors are required to analyse the by-products.

  18. Electrochemical advanced oxidation and biological processes for wastewater treatment: a review of the combined approaches.

    PubMed

    Ganzenko, Oleksandra; Huguenot, David; van Hullebusch, Eric D; Esposito, Giovanni; Oturan, Mehmet A

    2014-01-01

    As pollution becomes one of the biggest environmental challenges of the twenty-first century, pollution of water threatens the very existence of humanity, making immediate action a priority. The most persistent and hazardous pollutants come from industrial and agricultural activities; therefore, effective treatment of this wastewater prior to discharge into the natural environment is the solution. Advanced oxidation processes (AOPs) have caused increased interest due to their ability to degrade hazardous substances in contrast to other methods, which mainly only transfer pollution from wastewater to sludge, a membrane filter, or an adsorbent. Among a great variety of different AOPs, a group of electrochemical advanced oxidation processes (EAOPs), including electro-Fenton, is emerging as an environmental-friendly and effective treatment process for the destruction of persistent hazardous contaminants. The only concern that slows down a large-scale implementation is energy consumption and related investment and operational costs. A combination of EAOPs with biological treatment is an interesting solution. In such a synergetic way, removal efficiency is maximized, while minimizing operational costs. The goal of this review is to present cutting-edge research for treatment of three common and problematic pollutants and effluents: dyes and textile wastewater, olive processing wastewater, and pharmaceuticals and hospital wastewater. Each of these types is regarded in terms of recent scientific research on individual electrochemical, individual biological and a combined synergetic treatment.

  19. Degradation of estrone in water and wastewater by various advanced oxidation processes.

    PubMed

    Sarkar, Shubhajit; Ali, Sura; Rehmann, Lars; Nakhla, George; Ray, Madhumita B

    2014-08-15

    A comprehensive study was conducted to determine the relative efficacy of various advanced oxidation processes such as O3, H2O2, UV, and combinations of UV/O3, UV/H2O2 for the removal of estrone (E1) from pure water and secondary effluent. In addition to the parent compound (E1) removal, performance of the advanced oxidation processes was characterized using removal of total organic carbon (TOC), and estrogenicity of the effluent. Although E1 removal was high for all the AOPs, intermediates formed were more difficult to degrade leading to slow TOC removal. Energy calculations and cost analysis indicated that, although UV processes have low electricity cost, ozonation is the least cost option ($ 0.34/1000 gallons) when both capital and operating costs were taken into account. Ozonation also is superior to the other tested AOPs due to higher removal of TOC and estrogenicity. The rate of E1 removal decreased linearly with the background TOC in water, however, E1 degradation in the secondary effluent from a local wastewater treatment plant was not affected significantly due to the low COD values in the effluent.

  20. Degradation of diethyl phthalate in treated effluents from an MBR via advanced oxidation processes: effects of nitrate on oxidation and a pilot-scale AOP operation.

    PubMed

    Park, J H; Park, C G; Lee, J W; Ko, K B

    2010-01-01

    The major objective of this study was to delineate the oxidation of diethyl phthalate (DEP) in water, using bench-scale UV/H2O2 and O3/H2O2 processes, and to determine the effects of nitrate (NO(3-)-N, 5 mg L(-1)) on this oxidation. The oxidation of DEP was also investigated through a pilot-scale advanced oxidation process (AOP), into which a portion of the effluent from a pilot-scale membrane bioreactor (MBR) plant was pumped. The bench-scale operation showed that DEP could be oxidized via solely UV oxidation or O3 oxidation. The adverse effect of nitrate on the DEP oxidation was remarkable in the UV/H2O2 process, and the nitrate clearly reduced its oxidation. The adverse effect of nitrate on O3 oxidation was also observed. It was noted, however, that the nitrate clearly enhanced the DEP oxidation in the O3/H2O2 process. A series of pilot-scale AOP operations indicated that the addition of H2O2 enhanced DEP oxidation in both the UV/H2O2 and O3/H2O2 processes. No noticeable adverse effect of nitrate was observed in the NO(3-)-N concentration of about 6.0 mg L(-1), which was naturally contained in the treatment stream. About 52% and 61% of the DEP were oxidized by each of these two oxidation processes in this pilot-scale operation. Both the UV/H2O2 and O3/H2O2 processes appeared to be desirable alternatives for DEP oxidation in treatment effluent streams.

  1. Organic Nitrogen-Driven Stimulation of Arbuscular Mycorrhizal Fungal Hyphae Correlates with Abundance of Ammonia Oxidizers

    PubMed Central

    Bukovská, Petra; Gryndler, Milan; Gryndlerová, Hana; Püschel, David; Jansa, Jan

    2016-01-01

    Large fraction of mineral nutrients in natural soil environments is recycled from complex and heterogeneously distributed organic sources. These sources are explored by both roots and associated mycorrhizal fungi. However, the mechanisms behind the responses of arbuscular mycorrhizal (AM) hyphal networks to soil organic patches of different qualities remain little understood. Therefore, we conducted a multiple-choice experiment examining hyphal responses to different soil patches within the root-free zone by two AM fungal species (Rhizophagus irregularis and Claroideoglomus claroideum) associated with Medicago truncatula, a legume forming nitrogen-fixing root nodules. Hyphal colonization of the patches was assessed microscopically and by quantitative real-time PCR (qPCR) using AM taxon-specific markers, and the prokaryotic and fungal communities in the patches (pooled per organic amendment treatment) were profiled by 454-amplicon sequencing. Specific qPCR markers were then designed and used to quantify the abundance of prokaryotic taxa showing the strongest correlation with the pattern of AM hyphal proliferation in the organic patches as per the 454-sequencing. The hyphal density of both AM fungi increased due to nitrogen (N)-containing organic amendments (i.e., chitin, DNA, albumin, and clover biomass), while no responses as compared to the non-amended soil patch were recorded for cellulose, phytate, or inorganic phosphate amendments. Abundances of several prokaryotes, including Nitrosospira sp. (an ammonium oxidizer) and an unknown prokaryote with affiliation to Acanthamoeba endosymbiont, which were frequently recorded in the 454-sequencing profiles, correlated positively with the hyphal responses of R. irregularis to the soil amendments. Strong correlation between abundance of these two prokaryotes and the hyphal responses to organic soil amendments by both AM fungi was then confirmed by qPCR analyses using all individual replicate patch samples. Further

  2. Organic Nitrogen-Driven Stimulation of Arbuscular Mycorrhizal Fungal Hyphae Correlates with Abundance of Ammonia Oxidizers.

    PubMed

    Bukovská, Petra; Gryndler, Milan; Gryndlerová, Hana; Püschel, David; Jansa, Jan

    2016-01-01

    Large fraction of mineral nutrients in natural soil environments is recycled from complex and heterogeneously distributed organic sources. These sources are explored by both roots and associated mycorrhizal fungi. However, the mechanisms behind the responses of arbuscular mycorrhizal (AM) hyphal networks to soil organic patches of different qualities remain little understood. Therefore, we conducted a multiple-choice experiment examining hyphal responses to different soil patches within the root-free zone by two AM fungal species (Rhizophagus irregularis and Claroideoglomus claroideum) associated with Medicago truncatula, a legume forming nitrogen-fixing root nodules. Hyphal colonization of the patches was assessed microscopically and by quantitative real-time PCR (qPCR) using AM taxon-specific markers, and the prokaryotic and fungal communities in the patches (pooled per organic amendment treatment) were profiled by 454-amplicon sequencing. Specific qPCR markers were then designed and used to quantify the abundance of prokaryotic taxa showing the strongest correlation with the pattern of AM hyphal proliferation in the organic patches as per the 454-sequencing. The hyphal density of both AM fungi increased due to nitrogen (N)-containing organic amendments (i.e., chitin, DNA, albumin, and clover biomass), while no responses as compared to the non-amended soil patch were recorded for cellulose, phytate, or inorganic phosphate amendments. Abundances of several prokaryotes, including Nitrosospira sp. (an ammonium oxidizer) and an unknown prokaryote with affiliation to Acanthamoeba endosymbiont, which were frequently recorded in the 454-sequencing profiles, correlated positively with the hyphal responses of R. irregularis to the soil amendments. Strong correlation between abundance of these two prokaryotes and the hyphal responses to organic soil amendments by both AM fungi was then confirmed by qPCR analyses using all individual replicate patch samples. Further

  3. Nitrous oxide emission budgets and land-use-driven hotspots for organic soils in Europe

    NASA Astrophysics Data System (ADS)

    Leppelt, T.; Dechow, R.; Gebbert, S.; Freibauer, A.; Lohila, A.; Augustin, J.; Drösler, M.; Fiedler, S.; Glatzel, S.; Höper, H.; Järveoja, J.; Lærke, P. E.; Maljanen, M.; Mander, Ü.; Mäkiranta, P.; Minkkinen, K.; Ojanen, P.; Regina, K.; Strömgren, M.

    2014-12-01

    Organic soils are a main source of direct emissions of nitrous oxide (N2O), an important greenhouse gas (GHG). Observed N2O emissions from organic soils are highly variable in space and time, which causes high uncertainties in national emission inventories. Those uncertainties could be reduced when relating the upscaling process to a priori-identified key drivers by using available N2O observations from plot scale in empirical approaches. We used the empirical fuzzy modelling approach MODE to identify main drivers for N2O and utilize them to predict the spatial emission pattern of European organic soils. We conducted a meta-study with a total amount of 659 annual N2O measurements, which was used to derive separate models for different land use types. We applied our models to available, spatially explicit input driver maps to upscale N2O emissions at European level and compared the inventory with recently published IPCC emission factors. The final statistical models explained up to 60% of the N2O variance. Our study results showed that cropland and grasslands emitted the highest N2O fluxes 0.98 ± 1.08 and 0.58 ± 1.03 g N2O-N m-2 a-1, respectively. High fluxes from cropland sites were mainly controlled by low soil pH value and deep-drained groundwater tables. Grassland hotspot emissions were strongly related to high amount of N-fertilizer inputs and warmer winter temperatures. In contrast, N2O fluxes from natural peatlands were predominantly low (0.07 ± 0.27 g N2O-N m-2 a-1) and we found no relationship with the tested drivers. The total inventory for direct N2O emissions from organic soils in Europe amount up to 149.5 Gg N2O-N a-1, which also included fluxes from forest and peat extraction sites and exceeds the inventory calculated by IPCC emission factors of 87.4 Gg N2O-N a-1. N2O emissions from organic soils represent up to 13% of total European N2O emissions reported in the European Union (EU) greenhouse gas inventory of 2011 from only 7% of the EU area

  4. Nitrogen Oxide Measurements in Urban Environments Using a Novel LED-Driven Long-Path DOAS Instrument

    NASA Astrophysics Data System (ADS)

    Kern, C.; Trick, S.; Zingler, J.; Rippel, B.; Pedersen, D.; Platt, U.

    2005-12-01

    Nitrogen oxides and especially the nitrate radical play an important role in the chemical processes of the urban boundary layer. The long-path Differential Optical Absorption Spectroscopy (DOAS) measurement technique is a well established method for measuring atmospheric trace gases such as these along a defined light path. Steady advances in light-emitting diode (LED) technology have led to the applicability of LEDs as light sources for active DOAS measurements, where they represent a potentially very advantageous alternative to common thermal emitters for a variety of reasons including low cost, high durability and reduced power consumption. The assets and drawbacks of these modern light sources will be discussed, and the design of a first LED-powered instrument shown. The novel instrumentation was used to conduct nitrogen oxide measurements over the cites of Heidelberg and Jerusalem. In both cases, NO3 mixing ratios upwards of 150 ppt were found on some nights. The results of these experiments will be presented along with their implications for the chemistry of urban source regions.

  5. Employing Microbial Electrochemical Technology-driven electro-Fenton oxidation for the removal of recalcitrant organics from sanitary landfill leachate.

    PubMed

    Hassan, Muhammad; Pous, Narcis; Xie, Bing; Colprim, Jesús; Balaguer, M Dolors; Puig, Sebastia

    2017-07-08

    The feasibility of employing Microbial Electrochemical Technology (MET)-driven electro-Fenton oxidation was evaluated as a post-treatment of an anammox system treating sanitary landfill leachate. Two different MET configuration systems were operated using effluent from partial nitrification-anammox reactor treating mature leachate. In spite of the low organic matter biodegradability of the anammox's effluent (2401±562mgCODL(-1); 237±57mgBOD5L(-1)), the technology was capable to reach COD removal rates of 1077-1244mgL(-1)d(-1) with concomitant renewable electricity production (43.5±2.1Am(-3)NCC). The operation in continuous mode versus batch mode reinforced the removal capacity of the technology. The recirculation of acidic catholyte into anode chamber hindered the anodic efficiency due to pH stress on anodic electricigens. The obtained results demonstrated that the integrated system is a potentially applicable process to deal with bio-recalcitrant compounds present in mature landfill leachate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Fe-rich carbonate chimney in Okinawa Trough Implication for Fe-driven Microbial Anaerobic Oxidation of Methane (AMO)

    NASA Astrophysics Data System (ADS)

    Peng, X.; Guo, Z.

    2016-12-01

    Marine sediments associated with cold seeps at continental margins discharge substantial amounts of methane. Microbial anaerobic oxidation of methane (AMO) is a key biogeochemical process in these environments, which can trigger the formation of carbonate chimneys within sediments. The exact biogeochemical mechanism of how AMO control the formation of carbonate chimneys and influence their mineralogy and chemistry remains poorly constrained. Here, we use nano-scale secondary ion mass spectrometry to characterize the petrology and geochemistry of methane-derived Fe-rich carbonate chimneys formed between 5-7 Ma in the Northern Okinawa Trough. We find abundant framboid pyrites formed in the authigenic carbonates in the chimneys, indicating a non-Fe limitation sedimentary system. The δ13C values of carbonate (-18.9‰ to -45.9‰, PDB) show their probable origin from a mixing source of biogenic and thermogenic methane. The δ34S values range from -3.9 ± 0.5‰ to 23.2 ± 0.5‰ (VCDT), indicative of a strong exhaustion of sulfates in a local sulfate pool. We proposed that Fe-rich carbonate chimneys formed at the bottom of the sulfate-methane transition zone, beneath which Fe-driven AOM may happen and provide available ferrous for the extensive precipitation of pyrite in carbonate chimneys. The accumulation of reductive Fe in sediments via this process may widely occur in other analogous settings, with important application for Fe and S biogeochemical cycling within deep sediments at continental margins.

  7. Uniform distribution of graphene oxide sheets into a poly-vinylidene fluoride nanoparticle matrix through shear-driven aggregation.

    PubMed

    Sheng, Xinxin; Xie, Delong; Zhang, Xinya; Zhong, Li; Wu, Hua; Morbidelli, Massimo

    2016-07-06

    A general methodology has been developed for preparing nanocomposites with uniform, random distribution of fillers in polymer matrices, purely based on intense shear-driven aggregation, while avoiding filler aggregation. This procedure is demonstrated for a binary colloid composed of graphene oxide (GO) sheets and poly-vinylidene fluoride (PVDF) nanoparticles (NPs), both negatively charged and stable at rest. On the other hand, the PVDF NPs are shear-active (i.e. aggregation occurs under intensive shear), while the GO sheets are shear-inactive. It is found that when the two suspensions are mixed and the resulting binary colloid is forced to pass through a microchannel (MC) device (at a very high shear rate, G = 1.2 × 10(6) s(-1)), the shear-inactive GO sheets are captured and well distributed inside the PVDF NP clusters or gels. In addition, it is shown that in order to have 100% capture efficiency for the GO sheets, a minimum solid content of the binary colloid is required, which can be identified experimentally as the minimum leading to gelation after passing through the MC only one time.

  8. Diffused sunlight driven highly synergistic pathway for complete mineralization of organic contaminants using reduced graphene oxide supported photocatalyst.

    PubMed

    Babu, Sundaram Ganesh; Ramalingam Vinoth; Neppolian, Bernaurdshaw; Dionysiou, Dionysios D; Ashokkumar, Muthupandian

    2015-06-30

    Diffused sunlight is found to be an effective light source for the efficient degradation and mineralization of organic pollutant (methyl orange as a probe) by sono-photocatalytic degradation using reduced graphene oxide (rGO) supported CuO-TiO2 photocatalyst. The prepared catalysts are characterized by XRD, XPS, UV-vis DRS, PL, photoelectrochemical, SEM-EDS and TEM. A 10 fold synergy is achieved for the first time by combining sonochemical and photocatalytic degradation under diffused sunlight. rGO loading augments the activity of bare CuO-TiO2 more than two fold. The ability of rGO in storing, transferring, and shuttling electrons at the heterojunction between TiO2 and CuO facilitates the separation of photogenerated electron-hole pairs, as evidenced by the photoluminescence results. The complete mineralization of MO and the by-products within a short span of time is confirmed by TOC analysis. Further, hydroxyl radical mediated degradation under diffused sunlight is confirmed by LC-MS. This system shows similar activity for the degradation of methylene blue and 4-chlorophenol indicating the versatility of the catalyst for the degradation of various pollutants. This investigation is likely to open new possibilities for the development of highly efficient diffused sunlight driven TiO2 based photocatalysts for the complete mineralization of organic contaminants.

  9. In-situ synthesis of highly efficient visible light driven stannic oxide/graphitic carbon nitride heterostructured photocatalysts.

    PubMed

    Tao, Binglin; Yan, Zifeng

    2016-10-15

    Novel and efficient visible-light-driven stannic oxide/graphitic carbon nitride heterostructured photocatalysts are prepared via a simple in-situ solvothermal method. Characterization results demonstrate that there exist strong interactions between SnO2 nanoparticles and g-C3N4 matrix, which indicates the formation of SnO2/g-C3N4 heterojunction. The as-synthesized SnO2/g-C3N4 composite exhibits improved efficiency for photodegradation of rhodamine B in aqueous solutions, with an apparent rate constant 6.5 times higher than that of commercial TiO2 (Degussa P25). The enhanced photocatalytic activity is attributed to synergistic effect between SnO2 and g-C3N4, resulting in effective interfacial charge transfer and prolonged charge-hole separation time. Moreover, SnO2/g-C3N4 composite photocatalysts possess excellent durability and stability after 6 recycling runs, and a possible photocatalytic mechanism is also proposed. This research highlights the promising applications of two dimensional g-C3N4 based composite photocatalysts in the field of waste water disposal and environmental remediation. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Stability of 6:2 fluorotelomer sulfonate in advanced oxidation processes: degradation kinetics and pathway.

    PubMed

    Yang, Xiaoling; Huang, Jun; Zhang, Kunlun; Yu, Gang; Deng, Shubo; Wang, Bin

    2014-03-01

    Perfluorooctane sulfonate (PFOS), a widely used mist suppressant in hard chrome electroplating industry, has been listed in the Stockholm Convention for global ban. 6:2 Fluorotelomer sulfonate (6:2 FTS) acid and salts have been adopted as alternative products in the market, but no data about their abiotic degradation has been reported. In the present study, the degradability of 6:2 FTS potassium salt (6:2 FTS-K) was evaluated under various advanced oxidation processes, including ultraviolet (UV) irradiation, UV with hydrogen peroxide (H2O2), alkaline ozonation (O3, pH = 11), peroxone (O3/H2O2), and Fenton reagent oxidation (Fe(2+)/H2O2). UV/H2O2 was found to be the most effective approach, where the degradation of 6:2 FTS-K followed the pseudo-first-order kinetics. The intermediates were mainly shorter chain perfluoroalkyl carboxylic acid (C7 to C2), while sulfate (SO4 (2-)) and fluoride (F(-)) were found to be the final products. The high yields of SO4 (2-) and F(-) indicate that 6:2 FTS-K can be nearly completely desulfonated and defluorinated under UV/H2O2 condition. The degradation should firstly begin with the substitution of hydrogen atom by hydroxyl radicals, followed by desulfonation, carboxylation, and sequential "flake off" of CF2 unit. Compared with PFOS which is inert in most advanced oxidation processes, 6:2 FTS-K is more degradable as the alternative.

  11. Advanced oxidation treatment of physico-chemically pre-treated olive mill industry effluent.

    PubMed

    Gomec, Cigdem Y; Erdim, Esra; Turan, Ilknur; Aydin, Ali F; Ozturk, Izzet

    2007-08-01

    In this study, the applicability of physico-chemical methods was investigated for the pre-treatment of the olive mill effluents prior to the discharge into the common sewerage ending with a municipal wastewater treatment plant. The samples were taken from an olive oil industry operated as three-phase process located in Turkey. Various pre-treatment methods including acid craking, polyelectrolyte and lime additions were applied. Advanced oxidation study using Fenton's process was also investigated following pre-treatment by acid cracking and cationic polyelectrolyte. Acid cracking alone gave satisfactory treatment efficiencies and polyelectrolite additions to the acid-cracked samples enhanced treatment efficiency. Since a complete treatment plant is available at the end of the sewer system, results indicated that the effluents of the investigated industry could be discharged into the municipal sewerage in the case of total chemical oxygen demand (COD(tot)), suspended solid (SS) and volatile suspended solid (VSS) concentrations according to the Turkish Water Pollution Control Regulation after pre-treatment with 5 ppm anionic polyelectrolyte following acid cracking. The minimum COD(tot), SS and VSS removals were observed when raw wastewater was pre-treated with lime and the discharge standards to the municipal sewer system could not be met. Advanced oxidation with Fenton's process was applied after acid cracking and cationic polyelectrolyte treatment in order to investigate further reduction in chemical oxygen demand (COD) concentration for minimizing the influence of this industrial discharge on the existing municipal wastewater treatment plant. Results indicated that COD(tot) removal increased up to 89% from 74% after Fenton's oxidation for the acid cracked samples in which cationic polyelectrolite (10 ppm) was added.

  12. Advanced oxidation process based on the Cr(III)/Cr(VI) redox cycle.

    PubMed

    Bokare, Alok D; Choi, Wonyong

    2011-11-01

    Oxidative degradation of aqueous organic pollutants, using 4-chlorophenol (4-CP) as a main model substrate, was achieved with the concurrent H(2)O(2)-mediated transformation of Cr(III) to Cr(VI). The Fenton-like oxidation of 4-CP is initiated by the reaction between the aquo-complex of Cr(III) and H(2)O(2), which generates HO(•) along with the stepwise oxidation of Cr(III) to Cr(VI). The Cr(III)/H(2)O(2) system is inactive in acidic condition, but exhibits maximum oxidative capacity at neutral and near-alkaline pH. Since we previously reported that Cr(VI) can also activate H(2)O(2) to efficiently generate HO(•), the dual role of H(2)O(2) as an oxidant of Cr(III) and a reductant of Cr(VI) can be utilized to establish a redox cycle of Cr(III)-Cr(VI)-Cr(III). As a result, HO(•) can be generated using both Cr(III)/H(2)O(2) and Cr(VI)/H(2)O(2) reactions, either concurrently or sequentially. The formation of HO(•) was confirmed by monitoring the production of p-hydroxybenzoic acid from [benzoic acid + HO(•)] as a probe reaction and by quenching the degradation of 4-CP in the presence of methanol as a HO(•) scavenger. The oxidation rate of 4-CP in the Cr(III)/H(2)O(2) solution was highly influenced by pH, which is ascribed to the hydrolysis of Cr(III)(H(2)O)(n) into Cr(III)(H(2)O)(n-m)(OH)(m) and the subsequent condensation to oligomers. The present study proposes that the Cr(III)/H(2)O(2) combined with Cr(VI)/H(2)O(2) process is a viable advanced oxidation process that operates over a wide pH range using the reusable redox cycle of Cr(III) and Cr(VI).

  13. Decomposition of 1,4-dioxane by advanced oxidation and biochemical process.

    PubMed

    Kim, Chang-Gyun; Seo, Hyung-Joon; Lee, Byung-Ryul

    2006-01-01

    This study was undertaken to determine the optimal decomposition conditions when 1,4-dioxane was degraded using either the AOPs (Advanced Oxidation Processes) or the BAC-TERRA microbial complex. The advanced oxidation was operated with H2O2, in the range 4.7 to 51 mM, under 254 nm (25 W lamp) illumination, while varying the reaction parameters, such as the air flow rate and reaction time. The greatest oxidation rate (96%) of 1,4-dioxane was achieved with H2O2 concentration of 17 mM after a 2-hr reaction. As a result of this reaction, organic acid intermediates were formed, such as acetic, propionic and butyric acids. Furthermore, the study revealed that suspended particles, i.e., bio-flocs, kaolin and pozzolan, in the reaction were able to have an impact on the extent of 1,4-dioxane decomposition. The decomposition of 1,4-dioxane in the presence of bio-flocs was significantly declined due to hindered UV penetration through the solution as a result of the consistent dispersion of bio-particles. In contrast, dosing with pozzolan decomposed up to 98.8% of the 1,4-dioxane after 2 hr of reaction. Two actual wastewaters, from polyester manufacturing, containing 1,4-dioxane in the range 370 to 450 mg/L were able to be oxidized by as high as 100% within 15 min with the introduction of 100:200 (mg/L) Fe(II):H202 under UV illumination. Aerobic biological decomposition, employing BAC-TERRA, was able to remove up to 90% of 1,4-dioxane after 15 days of incubation. In the meantime, the by-products (i.e., acetic, propionic and valeric acid) generated were similar to those formed during the AOPs investigation. According to kinetic studies, both photo-decomposition and biodegradation of 1,4-dioxane followed pseudo first-order reaction kinetics, with k = 5 x 10(-4) s(-1) and 2.38 x 10(-6) s(-1), respectively. It was concluded that 1,4-dioxane could be readily degraded by both AOPs and BAC-TERRA, and that the actual polyester wastewater containing 1,4-dioxane could be successfully

  14. Recent Progress in Self‐Supported Metal Oxide Nanoarray Electrodes for Advanced Lithium‐Ion Batteries

    PubMed Central

    Zhang, Feng

    2016-01-01

    The rational design and fabrication of electrode materials with desirable architectures and optimized properties has been demonstrated to be an effective approach towards high‐performance lithium‐ion batteries (LIBs). Although nanostructured metal oxide electrodes with high specific capacity have been regarded as the most promising alternatives for replacing commercial electrodes in LIBs, their further developments are still faced with several challenges such as poor cycling stability and unsatisfying rate performance. As a new class of binder‐free electrodes for LIBs, self‐supported metal oxide nanoarray electrodes have many advantageous features in terms of high specific surface area, fast electron transport, improved charge transfer efficiency, and free space for alleviating volume expansion and preventing severe aggregation, holding great potential to solve the mentioned problems. This review highlights the recent progress in the utilization of self‐supported metal oxide nanoarrays grown on 2D planar and 3D porous substrates, such as 1D and 2D nanostructure arrays, hierarchical nanostructure arrays, and heterostructured nanoarrays, as anodes and cathodes for advanced LIBs. Furthermore, the potential applications of these binder‐free nanoarray electrodes for practical LIBs in full‐cell configuration are outlined. Finally, the future prospects of these self‐supported nanoarray electrodes are discussed. PMID:27711259

  15. Critical review of electrochemical advanced oxidation processes for water treatment applications.

    PubMed

    Chaplin, Brian P

    2014-05-01

    Electrochemical advanced oxidation processes (EAOPs) have emerged as novel water treatment technologies for the elimination of a broad-range of organic contaminants. Considerable validation of this technology has been performed at both the bench-scale and pilot-scale, which has been facilitated by the development of stable electrode materials that efficiently generate high yields of hydroxyl radicals (OH˙) (e.g., boron-doped diamond (BDD), doped-SnO2, PbO2, and substoichiometic- and doped-TiO2). Although a promising new technology, the mechanisms involved in the oxidation of organic compounds during EAOPs and the corresponding environmental impacts of their use have not been fully addressed. In order to unify the state of knowledge, identify research gaps, and stimulate new research in these areas, this review critically analyses published research pertaining to EAOPs. Specific topics covered in this review include (1) EAOP electrode types, (2) oxidation pathways of select classes of contaminants, (3) rate limitations in applied settings, and (4) long-term sustainability. Key challenges facing EAOP technologies are related to toxic byproduct formation (e.g., ClO4(-) and halogenated organic compounds) and low electro-active surface areas. These challenges must be addressed in future research in order for EAOPs to realize their full potential for water treatment.

  16. Toxicological and chemical assessment of arsenic-contaminated groundwater after electrochemical and advanced oxidation treatments.

    PubMed

    Radić, Sandra; Crnojević, Helena; Vujčić, Valerija; Gajski, Goran; Gerić, Marko; Cvetković, Želimira; Petra, Cvjetko; Garaj-Vrhovac, Vera; Oreščanin, Višnja

    2016-02-01

    Owing to its proven toxicity and mutagenicity, arsenic is regarded a principal pollutant in water used for drinking. The objective of this study was the toxicological and chemical evaluation of groundwater samples obtained from arsenic enriched drinking water wells before and after electrochemical and ozone-UV-H2O2-based advanced oxidation processes (EAOP). For this purpose, acute toxicity test with Daphnia magna and chronic toxicity test with Lemna minor L. were employed as well as in vitro bioassays using human peripheral blood lymphocytes (HPBLs). Several oxidative stress parameters were estimated in L.minor. Physicochemical analysis showed that EAOP treatment was highly efficient in arsenic but also in ammonia and organic compound removal from contaminated groundwater. Untreated groundwater caused only slight toxicity to HPBLs and D. magna in acute experiments. However, 7-day exposure of L. minor to raw groundwater elicited genotoxicity, a significant growth inhibition and oxidative stress injury. The observed genotoxicity and toxicity of raw groundwater samples was almost completely eliminated by EAOP treatment. Generally, the results obtained with L. minor were in agreement with those obtained in the chemical analysis suggesting the sensitivity of the model organism in monitoring of arsenic-contaminated groundwater. In parallel to chemical analysis, the implementation of chronic toxicity bioassays in a battery is recommended in the assessment of the toxic and genotoxic potential of such complex mixtures.

  17. Advanced oxidation protein products and total antioxidant activity in colorectal carcinoma.

    PubMed

    Avinash, S S; Anitha, M; Vinodchandran; Rao, Gayathri M; Sudha, K; Shetty, Beena V

    2009-01-01

    The present study was designed to assess the levels of advanced oxidation protein products (AOPP) and percent hemolysis (that indirectly indicates the degree of membrane damage secondary to lipid peroxidation) in colorectal carcinoma. Glutathione (GSH), total thiols and albumin were measured to determine the antioxidant status. Considering the dynamic interaction between various antioxidants in the body, we measured the total antioxidant activity (AOA). Globulin was measured to assess the inflammatory response secondary to oxidative stress. Investigations were conducted in 45 cases of recently diagnosed primary colorectal adenocarcinoma. As control, 45 age and sex matched healthy persons were chosen. GSH was estimated in whole blood, percent hemolysis in RBC suspension and other parameters in plasma. We observed a very high significant increase (P<0.001) in AOPP, percent hemolysis and a highly significant increase (P<0.01) in globulin in colorectal carcinoma. We observed a very high significant decrease (P<0.001) in whole blood GSH, total thiols, albumin, AOA and a significant decrease (P<0.05) in plasma GSH in colorectal carcinoma. A very high significant negative correlation between percent hemolysis and AOA and an apparent negative correlation between total thiols and AOPP was seen in colorectal carcinoma. This demonstrated oxidative stress, decreased antioxidant status and secondary inflammatory response in colorectal carcinoma.

  18. Recent Progress in Self-Supported Metal Oxide Nanoarray Electrodes for Advanced Lithium-Ion Batteries.

    PubMed

    Zhang, Feng; Qi, Limin

    2016-09-01

    The rational design and fabrication of electrode materials with desirable architectures and optimized properties has been demonstrated to be an effective approach towards high-performance lithium-ion batteries (LIBs). Although nanostructured metal oxide electrodes with high specific capacity have been regarded as the most promising alternatives for replacing commercial electrodes in LIBs, their further developments are still faced with several challenges such as poor cycling stability and unsatisfying rate performance. As a new class of binder-free electrodes for LIBs, self-supported metal oxide nanoarray electrodes have many advantageous features in terms of high specific surface area, fast electron transport, improved charge transfer efficiency, and free space for alleviating volume expansion and preventing severe aggregation, holding great potential to solve the mentioned problems. This review highlights the recent progress in the utilization of self-supported metal oxide nanoarrays grown on 2D planar and 3D porous substrates, such as 1D and 2D nanostructure arrays, hierarchical nanostructure arrays, and heterostructured nanoarrays, as anodes and cathodes for advanced LIBs. Furthermore, the potential applications of these binder-free nanoarray electrodes for practical LIBs in full-cell configuration are outlined. Finally, the future prospects of these self-supported nanoarray electrodes are discussed.

  19. Mechanistic Study of the Validity of Using Hydroxyl Radical Probes To Characterize Electrochemical Advanced Oxidation Processes.

    PubMed

    Jing, Yin; Chaplin, Brian P

    2017-02-21

    The detection of hydroxyl radicals (OH(•)) is typically accomplished by using reactive probe molecules, but prior studies have not thoroughly investigated the suitability of these probes for use in electrochemical advanced oxidation processes (EAOPs), due to the neglect of alternative reaction mechanisms. In this study, we investigated the suitability of four OH(•) probes (coumarin, p-chlorobenzoic acid, terephthalic acid, and p-benzoquinone) for use in EAOPs. Experimental results indicated that both coumarin and p-chlorobenzoic acid are oxidized via direct electron transfer reactions, while p-benzoquinone and terephthalic acid are not. Coumarin oxidation to form the OH(•) adduct product 7-hydroxycoumarin was found at anodic potentials lower than that necessary for OH(•) formation. Density functional theory (DFT) simulations found a thermodynamically favorable and non-OH(•) mediated pathway for 7-hydroxycoumarin formation, which is activationless at anodic potentials > 2.10 V/SHE. DFT simulations also provided estimates of E° values for a series of OH(•) probe compounds, which agreed with voltammetry results. Results from this study indicated that terephthalic acid is the most appropriate OH(•) probe compound for the characterization of electrochemical and catalytic systems.

  20. Degradation of triketone herbicides, mesotrione and sulcotrione, using advanced oxidation processes.

    PubMed

    Jović, Milica; Manojlović, Dragan; Stanković, Dalibor; Dojčinović, Biljana; Obradović, Bratislav; Gašić, Uroš; Roglić, Goran

    2013-09-15

    Degradation of two triketone herbicides, mesotrione and sulcotrione, was studied using four different advanced oxidation processes (AOPs): ozonization, dielectric barrier discharge (DBD reactor), photocatalysis and Fenton reagent, in order to find differences in mechanism of degradation. Degradation products were identified by high performance liquid chromatography (HPLC-DAD) and UHPLC-Orbitrap-MS analyses. A simple mechanism of degradation for different AOP was proposed. Thirteen products were identified during all degradations for both pesticides. It was assumed that the oxidation mechanisms in the all four technologies were not based only on the production and use of the hydroxyl radical, but they also included other kinds of oxidation mechanisms specific for each technology. Similarity was observed between degradation mechanism of ozonation and DBD. The greatest difference in the products was found in Fenton degradation which included the opening of benzene ring. When degraded with same AOP pesticides gave at the end of treatment the same products. Global toxicity and COD value of samples was determined after all degradations. Real water sample was used to study influence of organic matter on pesticide degradation. These results could lead to accurate estimates of the overall effects of triketone herbicides on environmental ecosystems and also contributed to the development of improved removal processes.

  1. Performance evaluation of different solar advanced oxidation processes applied to the treatment of a real textile dyeing wastewater.

    PubMed

    Manenti, Diego R; Soares, Petrick A; Silva, Tânia F C V; Módenes, Aparecido N; Espinoza-Quiñones, Fernando R; Bergamasco, Rosângela; Boaventura, Rui A R; Vilar, Vítor J P

    2015-01-01

    The performance of different solar-driven advanced oxidation processes (AOPs), such as TiO2/UV, TiO2/H2O2/UV, and Fe(2+)/H2O2/UV-visible in the treatment of a real textile effluent using a pilot plant with compound parabolic collectors (CPCs), was investigated. The influence of the main photo-Fenton reaction variables such as iron concentration (20-100 mg Fe(2+) L(-1)), pH (2.4-4.5), temperature (10-50 °C), and irradiance (22-68 WUV m(-2)) was evaluated in a lab-scale prototype using artificial solar radiation. The real textile wastewater presented a beige color, with a maximum absorbance peak at 641 nm, alkaline pH (8.1), moderate organic content (dissolved organic carbon (DOC) = 129 mg C L(-1) and chemical oxygen demand (COD) = 496 mg O2 L(-1)), and high conductivity mainly associated to the high concentration of chloride (1.1 g Cl(-) L(-1)), sulfate (0.4 g SO 4 (2 -) L(- 1)), and sodium (1.2 g Na(+) L(-1)) ions. Although all the processes tested contributed to complete decolorization and effective mineralization, the most efficient process was the solar photo-Fenton with an optimum catalyst concentration of 60 mg Fe(2+) L(-1), leading to 70 % mineralization (DOCfinal = 41 mg C L(-1); CODfinal < 150 mg O2 L(-1)) at pH 3.6, requiring a UV energy dose of 3.5 kJUV L(-1) (t 30 W = 22.4 min; [Formula: see text]; [Formula: see text]) and consuming 18.5 mM of H2O2.

  2. Evaluation of the advanced mixed oxide fuel test FO-2 irradiated in Fast Flux Test Facility

    SciTech Connect

    Gilpin, L.L.; Baker, R.B.; Chastain, S.A.

    1989-05-01

    The advanced mixed-oxide (UO/sub 2/-PuO/sub 2/) test assembly, FO-2, irradiated in the Fast Flux Test Facility (FFTF), is undergoing postirradiation examination (PIE). This is one of the first FFTF tests examined that used the advanced ferrite-martensite alloy, HT9, which is highly resistant to irradiation swelling. The FO-2 includes the first annular fueled pins irradiated in FFTF to undergo destructive examination. The FO-2 is a lead assembly for the ongoing FFTF Core Demonstration Experiment (CDE) (Leggett and Omberg 1987) and was designed to evaluate the effects of fuel design variables, such as pellet density, smeared density, and fuel form (annular or solid fuel), on advanced pin performance. The assembly contains a total of 169 fuel pins of twelve different types. The test was irradiated for 312 equivalent full power days (EFPD) in FFTF. It had a peak pin power of 13.7 kW/ft and reached a peak burnup of 65.2 MWd/kgM with a peak fast fluence of 9.9 /times/ 10/sup 22/ n/cm/sup 2/ (E > 0.1 MeV). This document discusses the test and its results. 6 refs., 19 figs., 4 tabs.

  3. Jet outflow and open field line measurements on the C-2U advanced beam-driven field-reversed configuration plasma experiment

    SciTech Connect

    Sheftman, D. Gupta, D.; Roche, T.; Thompson, M. C.; Giammanco, F.; Conti, F.; Marsili, P.; Moreno, C. D.

    2016-11-15

    Knowledge and control of the axial outflow of plasma particles and energy along open-magnetic-field lines are of crucial importance to the stability and longevity of the advanced beam-driven field-reversed configuration plasma. An overview of the diagnostic methods used to perform measurements on the open field line plasma on C-2U is presented, including passive Doppler impurity spectroscopy, microwave interferometry, and triple Langmuir probe measurements. Results of these measurements provide the jet ion temperature and axial velocity, electron density, and high frequency density fluctuations.

  4. Jet outflow and open field line measurements on the C-2U advanced beam-driven field-reversed configuration plasma experiment

    NASA Astrophysics Data System (ADS)

    Sheftman, D.; Gupta, D.; Roche, T.; Thompson, M. C.; Giammanco, F.; Conti, F.; Marsili, P.; Moreno, C. D.

    2016-11-01

    Knowledge and control of the axial outflow of plasma particles and energy along open-magnetic-field lines are of crucial importance to the stability and longevity of the advanced beam-driven field-reversed configuration plasma. An overview of the diagnostic methods used to perform measurements on the open field line plasma on C-2U is presented, including passive Doppler impurity spectroscopy, microwave interferometry, and triple Langmuir probe measurements. Results of these measurements provide the jet ion temperature and axial velocity, electron density, and high frequency density fluctuations.

  5. Degradation of atrazine by electrochemical advanced oxidation processes using a boron-doped diamond anode.

    PubMed

    Borràs, Núria; Oliver, Ramon; Arias, Conchita; Brillas, Enric

    2010-06-24

    Solutions of 30 mg L(-1) of the herbicide atrazine have been degraded by environmentally friendly electrochemical advanced oxidation processes (EAOPs) such as anodic oxidation (AO), electro-Fenton (EF), and photoelectro-Fenton (PEF) using a small open and cylindrical cell with a boron-doped diamond (BDD) anode. AO has been carried out either with a stainless steel cathode or an O(2) diffusion cathode able to generate H(2)O(2). Hydroxyl radicals ((*)OH) formed at the BDD surface in all EAOPs and in the bulk from Fenton's reaction between added Fe(2+) and electrogenerated H(2)O(2) in EF and PEF are the main oxidants. All treatments yielded almost overall mineralization, although the rate for total organic carbon (TOC) removal is limited by the oxidation of persistent byproducts with (*)OH at the BDD surface. In AO, TOC abatement is enhanced by parallel electrochemical reduction of organics at the stainless steel cathode, while in PEF, it also increases from additional photolysis of intermediates by UVA light under the synergistic action of (*)OH in the bulk. The effect of current and pH on the degradative behavior of EAOPs has been examined to determine their optimum values. Atrazine decay always follows a pseudo-first-order reaction, being more rapidly destroyed from (*)OH in the bulk than at the BDD surface. Aromatic intermediates such as desethylatrazine, desethyldesisopropylatrazine, and cyanuric acid and short linear carboxylic acids such as formic, oxalic, and oxamic have been identified and quantified by reversed-phase and ion-exclusion HPLC, respectively. Released inorganic ions such as Cl(-), NO(3)(-), and NH(4)(+) have been followed by ionic chromatography.

  6. Advanced TEM characterization of oxide nanoparticles in ODS Fe–12Cr–5Al alloys

    DOE PAGES

    Unocic, Kinga A; Hoelzer, David T; Pint, Bruce A

    2016-01-01

    For oxide nanoparticles present in three oxide-dispersion-strengthened (ODS) Fe–12Cr–5Al alloys containing additions of (1) Y2O3 (125Y), (2) Y2O3 + ZrO2 (125YZ), and (3) Y2O3 + HfO2 (125YH), were investigated using transmission and scanning transmission electron microscopy. Furthermore, in all three alloys nano-sized (<3.5 nm) oxide particles distributed uniformly throughout the microstructure were characterized using advanced electron microscopy techniques. In the 125Y alloy, mainly Al2O3 and yttrium–aluminum garnet (YAG) phases (Y3Al5O12) were present, while in the 125YZ alloy, additional Zr(C,N) precipitates were identified. The 125YH alloy had the most complex precipitation sequence whereby in addition to the YAG and Al2O3 phases,more » Hf(C,N), Y2Hf2O7, and HfO2 precipitates were also found. The presence of HfO2 was mainly due to the incomplete incorporation of HfO2 powder during mechanical alloying of the 125YH alloy. The alloy having the highest total number density of the oxides, the smallest grain size, and the highest Vickers hardness was the 125YZ alloy indicating, that Y2O3 + ZrO2 additions had the strongest effect on grain size and tensile properties. Finally, high-temperature mechanical testing will be addressed in the near future, while irradiation studies are underway to investigate the irradiation resistance of these new ODS FeCrAl alloys.« less

  7. Sequential ozone advanced oxidation and biological oxidation processes to remove selected pharmaceutical contaminants from an urban wastewater.

    PubMed

    Espejo, Azahara; Aguinaco, Almudena; García-Araya, J F; Beltrán, Fernando J

    2014-01-01

    Sequential treatments consisting in a chemical process followed by a conventional biological treatment, have been applied to remove mixtures of nine contaminants of pharmaceutical type spiked in a primary sedimentation effluent of a municipal wastewater. Combinations of ozone, UVA black light (BL) and Fe(III) or Fe₃O₄ catalysts constituted the chemical systems. Regardless of the Advanced Oxidation Process (AOP), the removal of pharmaceutical compounds was achieved in 1 h of reaction, while total organic carbon (TOC) only diminished between 3.4 and 6%. Among selected ozonation systems to be implemented before the biological treatment, the application of ozone alone in the pre-treatment stage is recommended due to the increase of the biodegradability observed. The application of ozone followed by the conventional biological treatment leads high TOC and COD removal rates, 60 and 61%, respectively, and allows the subsequent biological treatment works with shorter hydraulic residence time (HRT). Moreover, the influence of the application of AOPs before and after a conventional biological process was compared, concluding that the decision to take depends on the characterization of the initial wastewater with pharmaceutical compounds.

  8. Incorporation of electrochemical advanced oxidation processes in a multistage treatment system for sanitary landfill leachate.

    PubMed

    Moreira, Francisca C; Soler, J; Fonseca, Amélia; Saraiva, Isabel; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

    2015-09-15

    The current study has proved the technical feasibility of including electrochemical advanced oxidation processes (EAOPs) in a multistage strategy for the remediation of a sanitary landfill leachate that embraced: (i) first biological treatment to remove the biodegradable organic fraction, oxidize ammonium and reduce alkalinity, (ii) coagulation of the bio-treated leachate to precipitate humic acids and particles, followed by separation of the clarified effluent, and (iii) oxidation of the resulting effluent by an EAOP to degrade the recalcitrant organic matter and increase its biodegradability so that a second biological process for removal of biodegradable organics and nitrogen content could be applied. The influence of current density on an UVA photoelectro-Fenton (PEF) process was firstly assessed. The oxidation ability of various EAOPs such as electro-Fenton (EF) with two distinct initial total dissolved iron concentrations ([TDI]0), PEF and solar PEF (SPEF) was further evaluated and these processes were compared with their analogous chemical ones. A detailed assessment of the two first treatment stages was made and the biodegradability enhancement during the SPEF process was determined by a Zahn-Wellens test to define the ideal organics oxidation state to stop the EAOP and apply the second biological treatment. The best current density was 200 mA cm(-2) for a PEF process using a BDD anode, [TDI]0 of 60 mg L(-1), pH 2.8 and 20 °C. The relative oxidation ability of EAOPs increased in the order EF with 12 mg [TDI]0 L(-1) < EF with 60 mg [TDI]0 L(-1) < PEF with 60 mg [TDI]0 L(-1) ≤ SPEF with 60 mg [TDI]0 L(-1), using the abovementioned conditions. While EF process was much superior to the Fenton one, the superiority of PEF over photo-Fenton was less evident and SPEF attained similar degradation to solar photo-Fenton. To provide a final dissolved organic carbon (DOC) of 163 mg L(-1) to fulfill the discharge limits into the environment after

  9. Amorphous mixed-metal hydroxide nanostructures for advanced water oxidation catalysts

    NASA Astrophysics Data System (ADS)

    Gao, Y. Q.; Liu, X. Y.; Yang, G. W.

    2016-02-01

    The design of highly efficient, durable, and earth-abundant catalysts for the oxygen evolution reaction (OER) is crucial in order to promote energy conversion and storage processes. Here, we synthesize amorphous mixed-metal (Ni-Fe) hydroxide nanostructures with a homogeneous distribution of Ni/Fe as well as a tunable Ni/Fe ratio by a simple, facile, green and low-cost electrochemical technique, and we demonstrate that the synthesized amorphous nanomaterials possess ultrahigh activity and super long-term cycle stability in the OER process. The amorphous Ni0.71Fe0.29(OH)x nanostructure affords a current density of 10 mA cm-2 at an overpotential of a mere 0.296 V and a small Tafel slope of 58 mV dec-1, while no deactivation is detected in the CV testing even up to 30 000 cycles, which suggests the promising application of these amorphous nanomaterials in electrochemical oxidation. Meanwhile, the distinct catalytic activities among these amorphous Ni-Fe hydroxide nanostructures prompts us to take notice of the composition of the alloy hydroxides/oxides when studying their catalytic properties, which opens an avenue for the rational design and controllable preparation of such amorphous nanomaterials as advanced OER electrocatalysts.The design of highly efficient, durable, and earth-abundant catalysts for the oxygen evolution reaction (OER) is crucial in order to promote energy conversion and storage processes. Here, we synthesize amorphous mixed-metal (Ni-Fe) hydroxide nanostructures with a homogeneous distribution of Ni/Fe as well as a tunable Ni/Fe ratio by a simple, facile, green and low-cost electrochemical technique, and we demonstrate that the synthesized amorphous nanomaterials possess ultrahigh activity and super long-term cycle stability in the OER process. The amorphous Ni0.71Fe0.29(OH)x nanostructure affords a current density of 10 mA cm-2 at an overpotential of a mere 0.296 V and a small Tafel slope of 58 mV dec-1, while no deactivation is detected in the CV

  10. Advanced treatment of biologically pretreated coal gasification wastewater by a novel integration of catalytic ultrasound oxidation and membrane bioreactor.

    PubMed

    Jia, Shengyong; Han, Hongjun; Zhuang, Haifeng; Xu, Peng; Hou, Baolin

    2015-01-01

    Laboratorial scale experiments were conducted to investigate a novel system integrating catalytic ultrasound oxidation (CUO) with membrane bioreactor (CUO-MBR) on advanced treatment of biologically pretreated coal gasification wastewater. Results indicated that CUO with catalyst of FeOx/SBAC (sewage sludge based activated carbon (SBAC) which loaded Fe oxides) represented high efficiencies in eliminating TOC as well as improving the biodegradability. The integrated CUO-MBR system with low energy intensity and high frequency was more effective in eliminating COD, BOD5, TOC and reducing transmembrane pressure than either conventional MBR or ultrasound oxidation integrated MBR. The enhanced hydroxyl radical oxidation, facilitation of substrate diffusion and improvement of cell enzyme secretion were the mechanisms for CUO-MBR performance. Therefore, the integrated CUO-MBR was the promising technology for advanced treatment in engineering applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Simultaneous nitrate reduction and acetaminophen oxidation using the continuous-flow chemical-less VUV process as an integrated advanced oxidation and reduction process.

    PubMed

    Moussavi, Gholamreza; Shekoohiyan, Sakine

    2016-11-15

    This work was aimed at investigating the performance of the continuous-flow VUV photoreactor as a novel chemical-less advanced process for simultaneously oxidizing acetaminophen (ACT) as a model of pharmaceuticals and reducing nitrate in a single reactor. Solution pH was an important parameter affecting the performance of VUV; the highest ACT oxidation and nitrate reduction attained at solution pH between 6 and 8. The ACT was oxidized mainly by HO while the aqueous electrons were the main working agents in the reduction of nitrate. The performance of VUV photoreactor improved with the increase of hydraulic retention time (HRT); the complete degradation of ACT and ∼99% reduction of nitrate with 100% N2 selectivity achieved at HRT of 80min. The VUV effluent concentrations of nitrite and ammonium at HRT of 80min were below the drinking water standards. The real water sample contaminated with the ACT and nitrate was efficiently treated in the VUV photoreactor. Therefore, the VUV photoreactor is a chemical-less advanced process in which both advanced oxidation and advanced reduction reactions are accomplished. This unique feature possesses VUV photoreactor as a promising method of treating water contaminated with both pharmaceutical and nitrate. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Noise Survey Under Static Conditions of a Turbine-Driven Transonic Propeller with an Advance Ratio of 4.0

    NASA Technical Reports Server (NTRS)

    Kurbjun, Max C.

    1959-01-01

    Overall sound-pressure levels and frequency spectra have been obtained under static conditions on a transonic propeller with an advance ratio of 4.0. This advance ratio represents a practical minimum tip speed for transonic flight speeds. The three-blade, 6.85-foot-diameter, 1,710-rpm propeller is powered by a turbine engine and is designed to operate at a forward Mach number of 0.82 at an altitude of 35,000 feet. The results consist of overall sound-pressure levels and frequency spectra obtained from analyses made of recordings taken during ground runups of the propeller with an advance ratio of 4.0. These results are compared with similar results obtained from a supersonic propeller having an advance ratio of 2.2 reported in NACA Technical Note 4059 and from a modified supersonic propeller having an advance ratio of 3.2 reported in NACA Technical Note 4172. The advance-ratio-4.0 propeller of the present investigation produced a maximum sound-pressure level of 117.5 decibels when corrected to 1,400 horsepower. This overall noise output represents a lowering of the maximum overall sound-pressure level by approximately 5 decibels from that of the advance-ratio-3.2 propeller and by 14 decibels from that of the advance-ratio-2.2 propeller at comparable engine horsepowers. The frequency spectrum for the present propeller was the same as that for the advance-ratio-3.2 propeller, that is, high sound-pressure levels for the low-blade-passage harmonics with a rapid decrease in level with increasing order of harmonic. The 5-decibels reduction, under static conditions, is not considered sufficient to warrant the increased weight and operational penalties that would accompany this selection over the more efficient advance-ratio-3.2 propeller. At high forward speeds, however, the noise level of the present advance-ratio-4.0 propeller, especially in the fre- quency range where passenger comfort is important, should probably be substantially lower than that of the advance

  13. Nitric Oxide Dysregulation in Platelets from Patients with Advanced Huntington Disease

    PubMed Central

    Maglione, Vittorio; Damato, Antonio; Amico, Enrico; Formisano, Luigi; Vecchione, Carmine; Squitieri, Ferdinando

    2014-01-01

    Nitric oxide (NO) is a biologically active inorganic molecule involved in the regulation of many physiological processes, such as control of blood flow, platelet adhesion, endocrine function, neurotransmission and neuromodulation. In the present study, for the first time, we investigated the modulation of NO signaling in platelets of HD patients. We recruited 55 patients with manifest HD and 28 gender- and age-matched healthy controls. Our data demonstrated that NO-mediated vasorelaxation, when evoked by supernatant from insulin-stimulated HD platelets, gradually worsens along disease course. The defective vasorelaxation seems to stem from a faulty release of NO from platelets of HD patients and, it is associated with impairment of eNOS phosphorylation (Ser1177) and activity. This study provides important insights about NO metabolism in HD and raises the hypothesis that the decrease of NO in platelets of HD individuals could be a good tool for monitoring advanced stages of the disease. PMID:24587005

  14. Evaluation of copper slag to catalyze advanced oxidation processes for the removal of phenol in water.

    PubMed

    Huanosta-Gutiérrez, T; Dantas, Renato F; Ramírez-Zamora, R M; Esplugas, S

    2012-04-30

    The aim of this work was to evaluate the use of copper slag to catalyze phenol degradation in water by advanced oxidation processes (AOPs). Copper slag was tested in combination with H(2)O(2) (slag/H(2)O(2)) and H(2)O(2)/UV (slag/H(2)O(2)/UV). The studied methods promoted the complete photocatalytic degradation of phenol. Besides, they were able to reduce about 50% the TOC content in the samples. Slag/H(2)O(2)/UV and slag/H(2)O(2) treatments have favored biodegradability increment along the reaction time. Nevertheless, the irradiated method achieved higher values of the biodegradability indicator (BOD(5)/TOC). The toxicity assessment indicated the formation of more toxic compounds in both treatments. However, the control of the reaction time would minimize the environmental impact of the effluents.

  15. Advanced oxidation processes for wastewater treatment using a plasma/ozone combination system

    NASA Astrophysics Data System (ADS)

    Takeuchi, Nozomi; Kamiya, Yu; Saeki, Ryo; Tachibana, Kosuke; Yasuoka, Koichi

    2014-10-01

    Advanced oxidation process (AOP) using OH radicals is a promising method for the decomposition of persistent organic compounds in wastewater. Although many types of plasma reactors have been developed for the AOP, they are unsuitable for the complete decomposition of highly concentrated organic compounds. The reason for the incomplete decomposition is that OH radicals, particularly at a high density, recombine among themselves to form hydrogen peroxide. We have developed a combination plasma reactor in which ozone gas is fed, so that the generated hydrogen peroxide is re-converted to OH radicals. Pulsed plasmas generated within oxygen bubbles supply not only OH radicals but also hydrogen peroxide into wastewater. The total organic carbon (TOC) of the wastewater was more than 1 gTOC/L. The TOC values decreased linearly with time, and the persistent compounds which could not be decomposed by ozone were completely mineralized within 8 h of operation.

  16. Advanced Oxidation of Tartrazine and Brilliant Blue with Pulsed Ultraviolet Light Emitting Diodes.

    PubMed

    Scott, Robert; Mudimbi, Patrick; Miller, Michael E; Magnuson, Matthew; Willison, Stuart; Phillips, Rebecca; Harper, Willie F

    2017-01-01

      This study investigated the effect of ultraviolet light-emitting diodes (UVLEDs) coupled with hydrogen peroxide as an advanced oxidation process (AOP) for the degradation of two test chemicals. Brilliant Blue FCF consistently exhibited greater degradation than tartrazine, with 83% degradation after 300 minutes at the 100% duty cycle compared with only 17% degradation of tartrazine under the same conditions. These differences are attributable to the structural properties of the compounds. Duty cycle was positively correlated with the first-order rate constants (k) for both chemicals but, interestingly, negatively correlated with the normalized first-order rate constants (k/duty cycle). Synergistic effects of both hydraulic mixing and LED duty cycle were manifested as novel oscillations in the effluent contaminant concentration. Further, LED output and efficiency were dependent upon duty cycle and less efficient over time perhaps due to heating effects on semiconductor performance.

  17. Pretreatment of whole blood using hydrogen peroxide and UV irradiation. Design of the advanced oxidation process.

    PubMed

    Bragg, Stefanie A; Armstrong, Kristie C; Xue, Zi-Ling

    2012-08-15

    A new process to pretreat blood samples has been developed. This process combines the Advanced Oxidation Process (AOP) treatment (using H(2)O(2) and UV irradiation) with acid deactivation of the enzyme catalase in blood. A four-cell reactor has been designed and built in house. The effect of pH on the AOP process has been investigated. The kinetics of the pretreatment process shows that at high C(H(2)O(2),t=0), the reaction is zeroth order with respect to C(H(2)O(2)) and first order with respect to C(blood). The rate limiting process is photon flux from the UV lamp. Degradation of whole blood has been compared with that of pure hemoglobin samples. The AOP pretreatment of the blood samples has led to the subsequent determination of chromium and zinc concentrations in the samples using electrochemical methods.

  18. Controlled synthesis of uniform BiVO4 microcolumns and advanced visible-light-driven photocatalytic activity for the degradation of metronidazole-contained wastewater.

    PubMed

    Yu, Chongfei; Dong, Shuying; Feng, Jinglan; Sun, Jingyu; Hu, Limin; Li, Yukun; Sun, Jianhui

    2014-02-01

    Well-defined, uniform bismuth vanadate (BiVO4) microcolumns were synthesized through a refined hydrothermal route. During the fabrication process, a detailed orthogonal design on the synthetic conditions was performed, aiming to optimize the experimental parameters to produce BiVO4 materials (BiVO4 (Opt.)) with the most prominent visible-light-driven photocatalytic efficiency, where the catalytic activities of the synthesized materials were evaluated via the decolorization of methylene blue under visible light irradiation. The BiVO4 (Opt.) were then targetedly produced according to the determined optimal conditions and well characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet and visible diffuse-reflectance spectroscopy and photoluminescence spectroscopy. Compared with the commercial P25-TiO2 photocatalysts, the as-synthesized BiVO4 (Opt.) displayed superior visible-light-driven photocatalytic activities for the degradation of metronidazole-contained wastewater with the presence of H2O2. The degradation efficiency of metronidazole reached up to 70 % within 180 min, leading to a brief speculation on the possibly major steps of the visible-light-driven photocatalytic process. The current study provides a distinctive route to design novel shaped BiVO4 architectures with advanced photocatalytic capacities for the treatment of organic pollutants in the aqueous environment.

  19. Can activated sludge treatments and advanced oxidation processes remove organophosphorus flame retardants?

    PubMed

    Cristale, Joyce; Ramos, Dayana D; Dantas, Renato F; Machulek Junior, Amilcar; Lacorte, Silvia; Sans, Carme; Esplugas, Santiago

    2016-01-01

    This study aims to determine the occurrence of 10 OPFRs (including chlorinated, nonchlorinated alkyl and aryl compounds) in influent, effluent wastewaters and partitioning into sludge of 5 wastewater treatment plants (WWTP) in Catalonia (Spain). All target OPFRs were detected in the WWTPs influents, and the total concentration ranged from 3.67 µg L(-1) to 150 µg L(-1). During activated sludge treatment, most OPFRs were accumulated in the sludge at concentrations from 35.3 to 9980 ng g(-1) dw. Chlorinated compounds tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP) and tris(2,3-dichloropropyl) phosphate (TDCPP) were not removed by the conventional activated sludge treatment and they were released by the effluents at approximately the same inlet concentration. On the contrary, aryl compounds tris(methylphenyl) phosphate (TMPP) and 2-ethylhexyl diphenyl phosphate (EHDP) together with alkyl tris(2-ethylhexyl) phosphate (TEHP) were not detected in any of the effluents. Advanced oxidation processes (UV/H2O2 and O3) were applied to investigate the degradability of recalcitrant OPFRs in WWTP effluents. Those detected in the effluent sample (TCEP, TCIPP, TDCPP, tributyl phosphate (TNBP), tri-iso-butyl phosphate (TIBP) and tris(2-butoxyethyl) phosphate (TBOEP)) had very low direct UV-C photolysis rates. TBOEP, TNBP and TIBP were degraded by UV/H2O2 and O3. Chlorinated compounds TCEP, TDCPP and TCIPP were the most recalcitrant OPFR to the advanced oxidation processes applied. The study provides information on the partitioning and degradability pathways of OPFR within conventional activated sludge WWTPs.

  20. Combined treatment technology based on synergism between hydrodynamic cavitation and advanced oxidation processes.

    PubMed

    Gogate, Parag R; Patil, Pankaj N

    2015-07-01

    The present work highlights the novel approach of combination of hydrodynamic cavitation and advanced oxidation processes for wastewater treatment. The initial part of the work concentrates on the critical analysis of the literature related to the combined approaches based on hydrodynamic cavitation followed by a case study of triazophos degradation using different approaches. The analysis of different combinations based on hydrodynamic cavitation with the Fenton chemistry, advanced Fenton chemistry, ozonation, photocatalytic oxidation, and use of hydrogen peroxide has been highlighted with recommendations for important design parameters. Subsequently degradation of triazophos pesticide in aqueous solution (20 ppm solution of commercially available triazophos pesticide) has been investigated using hydrodynamic cavitation and ozonation operated individually and in combination for the first time. Effect of different operating parameters like inlet pressure (1-8 bar) and initial pH (2.5-8) have been investigated initially. The effect of addition of Fenton's reagent at different loadings on the extent of degradation has also been investigated. The combined method of hydrodynamic cavitation and ozone has been studied using two approaches of injecting ozone in the solution tank and at the orifice (at the flow rate of 0.576 g/h and 1.95 g/h). About 50% degradation of triazophos was achieved by hydrodynamic cavitation alone under optimized operating parameters. About 80% degradation of triazophos was achieved by combination of hydrodynamic cavitation and Fenton's reagent whereas complete degradation was achieved using combination of hydrodynamic cavitation and ozonation. TOC removal of 96% was also obtained for the combination of ozone and hydrodynamic cavitation making it the best treatment strategy for removal of triazophos.

  1. Advanced oxidation degradation kinetics as a function of ultraviolet LED duty cycle.

    PubMed

    Duckworth, Kelsey; Spencer, Michael; Bates, Christopher; Miller, Michael E; Almquist, Catherine; Grimaila, Michael; Magnuson, Matthew; Willison, Stuart; Phillips, Rebecca; Racz, LeeAnn

    2015-01-01

    Ultraviolet (UV) light emitting diodes (LEDs) may be a viable option as a UV light source for advanced oxidation processes (AOPs) utilizing photocatalysts or oxidizing agents such as hydrogen peroxide. The effect of UV-LED duty cycle, expressed as the percentage of time the LED is powered, was investigated in an AOP with hydrogen peroxide, using methylene blue (MB) to assess contaminant degradation. The UV-LED AOP degraded the MB at all duty cycles. However, adsorption of MB onto the LED emitting surface caused a linear decline in reactor performance over time. With regard to the effect of duty cycle, the observed rate constant of MB degradation, after being adjusted to account for the duty cycle, was greater for 5 and 10% duty cycles than higher duty cycles, providing a value approximately 160% higher at 5% duty cycle than continuous operation. This increase in adjusted rate constant at low duty cycles, as well as contaminant fouling of the LED surface, may impact design and operational considerations for pulsed UV-LED AOP systems.

  2. Effects of advanced oxidation pretreatment on residual aluminum control in high humic acid water purification.

    PubMed

    Wang, Wendong; Li, Hua; Ding, Zhenzhen; Wang, Xiaochang

    2011-01-01

    Due to the formation of disinfection by-products and high concentrations of Al residue in drinking water purification, humic substances are a major component of organic matter in natural waters and have therefore received a great deal of attention in recent years. We investigated the effects of advanced oxidation pretreatment methods usually applied for removing dissolved organic matters on residual Al control. Results showed that the presence of humic acid increased residual Al concentration notably. With 15 mg/L of humic acid in raw water, the concentrations of soluble aluminum and total aluminum in the treated water were close to the quantity of Al addition. After increasing coagulant dosage from 12 to 120 mg/L, the total-Al in the treated water was controlled to below 0.2 mg/L. Purification systems with ozonation, chlorination, or potassium permanganate oxidation pretreatment units had little effects on residual Al control; while UV radiation decreased Al concentration notably. Combined with ozonation, the effects of UV radiation were enhanced. Optimal dosages were 0.5 mg O3/mg C and 3 hr for raw water with 15 mg/L of humic acid. Under UV light radiation, the combined forces or bonds that existed among humic acid molecules were destroyed; adsorption sites increased positively with radiation time, which promoted adsorption of humic acid onto polymeric aluminum and Al(OH)3(s). This work provides a new solution for humic acid coagulation and residual Al control for raw water with humic acid purification.

  3. Unexpected toxicity to aquatic organisms of some aqueous bisphenol A samples treated by advanced oxidation processes.

    PubMed

    Tišler, Tatjana; Erjavec, Boštjan; Kaplan, Renata; Şenilă, Marin; Pintar, Albin

    2015-01-01

    In this study, photocatalytic and catalytic wet-air oxidation (CWAO) processes were used to examine removal efficiency of bisphenol A from aqueous samples over several titanate nanotube-based catalysts. Unexpected toxicity of bisphenol A (BPA) samples treated by means of the CWAO process to some tested species was determined. In addition, the CWAO effluent was recycled five- or 10-fold in order to increase the number of interactions between the liquid phase and catalyst. Consequently, the inductively coupled plasma mass spectrometry (ICP-MS) analysis indicated higher concentrations of some toxic metals like chromium, nickel, molybdenum, silver, and zinc in the recycled samples in comparison to both the single-pass sample and the photocatalytically treated solution. The highest toxicity of five- and 10-fold recycled solutions in the CWAO process was observed in water fleas, which could be correlated to high concentrations of chromium, nickel, and silver detected in tested samples. The obtained results clearly demonstrated that aqueous samples treated by means of advanced oxidation processes should always be analyzed using (i) chemical analyses to assess removal of BPA and total organic carbon from treated aqueous samples, as well as (ii) a battery of aquatic organisms from different taxonomic groups to determine possible toxicity.

  4. Solar-Enhanced Advanced Oxidation Processes for Water Treatment: Simultaneous Removal of Pathogens and Chemical Pollutants

    PubMed Central

    Tsydenova, Oyuna; Batoev, Valeriy; Batoeva, Agniya

    2015-01-01

    The review explores the feasibility of simultaneous removal of pathogens and chemical pollutants by solar-enhanced advanced oxidation processes (AOPs). The AOPs are based on in-situ generation of reactive oxygen species (ROS), most notably hydroxyl radicals •OH, that are capable of destroying both pollutant molecules and pathogen cells. The review presents evidence of simultaneous removal of pathogens and chemical pollutants by photocatalytic processes, namely TiO2 photocatalysis and photo-Fenton. Complex water matrices with high loads of pathogens and chemical pollutants negatively affect the efficiency of disinfection and pollutant removal. This is due to competition between chemical substances and pathogens for generated ROS. Other possible negative effects include light screening, competitive photon absorption, adsorption on the catalyst surface (thereby inhibiting its photocatalytic activity), etc. Besides, some matrix components may serve as nutrients for pathogens, thus hindering the disinfection process. Each type of water/wastewater would require a tailor-made approach and the variables that were shown to influence the processes—catalyst/oxidant concentrations, incident radiation flux, and pH—need to be adjusted in order to achieve the required degree of pollutant and pathogen removal. Overall, the solar-enhanced AOPs hold promise as an environmentally-friendly way to substitute or supplement conventional water/wastewater treatment, particularly in areas without access to centralized drinking water or sewage/wastewater treatment facilities. PMID:26287222

  5. Advanced oxidation process-biological system for wastewater containing a recalcitrant pollutant.

    PubMed

    Oller, I; Malato, S; Sánchez-Pérez, J A; Maldonado, M I; Gernjak, W; Pérez-Estrada, L A

    2007-01-01

    Two advanced oxidation processes (AOPs), ozonation and photo-Fenton, combined with a pilot aerobic biological reactor at field scale were employed for the treatment of industrial non-biodegradable saline wastewater (TOC around 200 mgL(-1)) containing a biorecalcitrant compound, alpha-methylphenylglycine (MPG), at a concentration of 500 mgL(-1). Ozonation experiments were performed in a 50-L reactor with constant inlet ozone of 21.9 g m(-3). Solar photo-Fenton tests were carried out in a 75-L pilot plant made up of four compound parabolic collector (CPC) units. The catalyst concentration employed in this system was 20 mgL(-1) of Fe2+ and the H2O2 concentration was kept in the range of 200-500mgL(-1). Complete degradation of MPG was attained after 1,020 min of ozone treatment, while only 195 min were required for photo-Fenton. Samples from different stages of both AOPs were taken for Zahn-Wellens biocompatibility tests. Biodegradability enhancement of the industrial saline wastewater was confirmed (>70% biodegradability). Biodegradable compounds generated during the preliminary oxidative processes were biologically mineralised in a 170-L aerobic immobilised biomass reactor (IBR). The global efficiency of both AOP/biological combined systems was 90% removal of an initial TOC of over 500 mgL(-1).

  6. Feasibility studies: UV/chlorine advanced oxidation treatment for the removal of emerging contaminants.

    PubMed

    Sichel, C; Garcia, C; Andre, K

    2011-12-01

    UV/chlorine (UV/HOCl and UV/ClO(2)) Advanced Oxidation Processes (AOPs) were assessed with varying process layout and compared to the state of the art UV/H(2)O(2) AOP. The process comparison focused on the economical and energy saving potential of the UV/chlorine AOP. Therefore the experiments were performed at technical scale (250 L/h continuous flow reactor) and at process energies, oxidant and model contaminant concentrations expected in full scale reference plants. As model compounds the emerging contaminants (ECs): desethylatrazine, sulfamethoxazole, carbamazepine, diclofenac, benzotriazole, tolyltriazole, iopamidole and 17α-ethinylestradiol (EE2) were degraded at initial compound concentrations of 1 μg/L in tap water and matrixes with increased organic load (46 mg/L DOC). UV/chlorine AOP organic by-product forming potential was assessed for trihalomethanes (THMs) and N-Nitrosodimethylamine (NDMA). A process design was evaluated which can considerably reduce process costs, energy consumption and by-product generation from UV/HOCl AOPs.

  7. Combined advanced oxidation and biological treatment processes for the removal of pesticides from aqueous solutions.

    PubMed

    Lafi, Walid K; Al-Qodah, Z

    2006-09-01

    Advanced oxidation processes were combined with biological treatment processes in this study to remove both pesticides and then the COD load from aqueous solutions. It was found that O(3) and O(3)/UV oxidation systems were able to reach 90 and 100%, removal of the pesticide Deltamethrin, respectively, in a period of 210 min. The use of O(3) combined with UV radiation enhances pesticides degradation and the residual pesticide reaches zero in the case of Deltamethrin. The combined O(3)/UV system can reduce COD up to 20% if the pH of the solution is above 4. Both pesticide degradation and COD removal in the combined O(3)/UV system follow the pseudo-first-order kinetics and the parameters of this model were evaluated. The application of the biological treatment to remove the bulk COD from different types of feed solution was investigated. More than 95% COD removal was achieved when treated wastewater by the O(3)/UV system was fed to the bioreactor. The parameters of the proposed Grau model were estimated.

  8. Solar-Enhanced Advanced Oxidation Processes for Water Treatment: Simultaneous Removal of Pathogens and Chemical Pollutants.

    PubMed

    Tsydenova, Oyuna; Batoev, Valeriy; Batoeva, Agniya

    2015-08-14

    The review explores the feasibility of simultaneous removal of pathogens and chemical pollutants by solar-enhanced advanced oxidation processes (AOPs). The AOPs are based on in-situ generation of reactive oxygen species (ROS), most notably hydroxyl radicals •OH, that are capable of destroying both pollutant molecules and pathogen cells. The review presents evidence of simultaneous removal of pathogens and chemical pollutants by photocatalytic processes, namely TiO2 photocatalysis and photo-Fenton. Complex water matrices with high loads of pathogens and chemical pollutants negatively affect the efficiency of disinfection and pollutant removal. This is due to competition between chemical substances and pathogens for generated ROS. Other possible negative effects include light screening, competitive photon absorption, adsorption on the catalyst surface (thereby inhibiting its photocatalytic activity), etc. Besides, some matrix components may serve as nutrients for pathogens, thus hindering the disinfection process. Each type of water/wastewater would require a tailor-made approach and the variables that were shown to influence the processes-catalyst/oxidant concentrations, incident radiation flux, and pH-need to be adjusted in order to achieve the required degree of pollutant and pathogen removal. Overall, the solar-enhanced AOPs hold promise as an environmentally-friendly way to substitute or supplement conventional water/wastewater treatment, particularly in areas without access to centralized drinking water or sewage/wastewater treatment facilities.

  9. Degradation and changes in toxicity and biodegradability of tetracycline during ozone/ultraviolet-based advanced oxidation.

    PubMed

    Luu, Huyen Trang; Lee, Kisay

    2014-01-01

    Advanced oxidation processes (AOPs) composed of O3, H2O2 and ultraviolet (UV) were applied to degrade tetracycline (TC). Degradation efficiency was evaluated in terms of changes in absorbance (ABS) and total organic carbon (TOC). The change in biotoxicity was monitored with Escherichia coli and Vibrio fischeri. The improvement in biodegradability during oxidation was demonstrated through 5-day biochemical oxygen demand/chemical oxygen demand ratio and aerobic biological treatment. The combination of O3/H2O2/UV and O3/UV showed the best performance for the reductions in ABS and TOC. However, mineralization and detoxification were not perfect under the experimental conditions that were used in this study. Therefore, for the ultimate treatment of TC compounds, it is suggested that AOP treatment is followed by biological treatment, utilizing enhanced biodegradability. In this study, aerobic biological treatment by Pseudomonas putida was performed for O3/UV-treated TC. It was confirmed that O3/UV treatment improved TOC reduction and facilitated complete mineralization in biological treatment.

  10. Parabens abatement from surface waters by electrochemical advanced oxidation with boron doped diamond anodes.

    PubMed

    Domínguez, Joaquín R; Muñoz-Peña, Maria J; González, Teresa; Palo, Patricia; Cuerda-Correa, Eduardo M

    2016-10-01

    The removal efficiency of four commonly-used parabens by electrochemical advanced oxidation with boron-doped diamond anodes in two different aqueous matrices, namely ultrapure water and surface water from the Guadiana River, has been analyzed. Response surface methodology and a factorial, composite, central, orthogonal, and rotatable (FCCOR) statistical design of experiments have been used to optimize the process. The experimental results clearly show that the initial concentration of pollutants is the factor that influences the removal efficiency in a more remarkable manner in both aqueous matrices. As a rule, as the initial concentration of parabens increases, the removal efficiency decreases. The current density also affects the removal efficiency in a statistically significant manner in both aqueous matrices. In the water river aqueous matrix, a noticeable synergistic effect on the removal efficiency has been observed, probably due to the presence of chloride ions that increase the conductivity of the solution and contribute to the generation of strong secondary oxidant species such as chlorine or HClO/ClO (-). The use of a statistical design of experiments made it possible to determine the optimal conditions necessary to achieve total removal of the four parabens in ultrapure and river water aqueous matrices.

  11. Decolorization and degradation of reactive yellow HF aqueous solutions by electrochemical advanced oxidation processes.

    PubMed

    Bedolla-Guzman, A; Feria-Reyes, R; Gutierrez-Granados, S; Peralta-Hernández, Juan M

    2016-07-29

    Textile manufacturing is the one responsible for water bodies' contamination through the discharge of colored wastes. This work presents the study of reactive yellow HF (RYHF) dye degradation under two different electrochemical advanced oxidation processes (EAOP), namely anodic oxidation (AO) and electro-Fenton (EF)/boron-doped diamond (BDD) process. For the AO, 100 and 300 mg/L solutions using Pt and BDD as anodes in a 100 mL stirred tank cell were used, with a supporting electrolyte of 0.05 mol/L of Na2SO4 at pH 3 under 30 and 50 mA/cm(2) current density. The EF/BDD process was carried out in a flow reactor at 4 and 7 L/min to degrade 100, 200, and 300 mg/L RYHF solutions under 50 and 80 mA/cm(2). UV-Vis determinations were used for decolorization evaluation, while high-performance liquid chromatography (HPLC) method provided information on dye degradation rate.

  12. Inactivation of dinoflagellate Scripsiella trochoidea in synthetic ballast water by advanced oxidation processes.

    PubMed

    Yang, Zhishan; Jiang, Wenju; Zhang, Yi; Lim, T M

    2015-01-01

    Ship-borne ballast water contributes significantly to the transfer of non-indigenous species across aquatic environments. To reduce the risk of bio-invasion, ballast water should be treated before discharge. In this study, the efficiencies of several conventional and advanced oxidation processes were investigated for potential ballast water treatment, using a marine dinoflagellate species, Scripsiella trochoidea, as the indicator organism. A stable and consistent culture was obtained and treated by ultraviolet (UV) light, ozone (O3), hydrogen peroxide (H2O2), and their various combinations. UV apparently inactivated the cells after only 10 s of irradiation, but subsequently photo-reactivation of the cells was observed for all methods involving UV. O3 exhibited 100% inactivation efficiency after 5 min treatment, while H2O2 only achieved maximum 80% inactivation in the same duration. Combined methods, e.g. UV/O3 and UV/H2O2, were found to inhibit photo-reactivation and improve treatment efficiency to some degree, indicating the effectiveness of using combined treatment processes. The total residual oxidant (TRO) levels of the methods were determined, and the results indicated that UV and O3 generated the lowest and highest TRO, respectively. The synergic effect of combined processes on TRO generation was found to be insignificant, and thus UV/O3 was recommended as a potentially suitable treatment process for ballast water.

  13. Treatment of winery wastewater by electrochemical methods and advanced oxidation processes.

    PubMed

    Orescanin, Visnja; Kollar, Robert; Nad, Karlo; Mikelic, Ivanka Lovrencic; Gustek, Stefica Findri

    2013-01-01

    The aim of this research was development of new system for the treatment of highly polluted wastewater (COD = 10240 mg/L; SS = 2860 mg/L) originating from vine-making industry. The system consisted of the main treatment that included electrochemical methods (electro oxidation, electrocoagulation using stainless steel, iron and aluminum electrode sets) with simultaneous sonication and recirculation in strong electromagnetic field. Ozonation combined with UV irradiation in the presence of added hydrogen peroxide was applied for the post-treatment of the effluent. Following the combined treatment, the final removal efficiencies of the parameters color, turbidity, suspended solids and phosphates were over 99%, Fe, Cu and ammonia approximately 98%, while the removal of COD and sulfates was 77% and 62%, respectively. A new approach combining electrochemical methods with ultrasound in the strong electromagnetic field resulted in significantly better removal efficiencies for majority of the measured parameters compared to the biological methods, advanced oxidation processes or electrocoagulation. Reduction of the treatment time represents another advantage of this new approach.

  14. Design, properties, and weldability of advanced oxidation-resistant FeCrAl alloys

    DOE PAGES

    Gussev, M. N.; Field, K. G.; Yamamoto, Y.

    2017-05-05

    FeCrAl alloys are promising as corrosion- and oxidation-resistance materials for extreme high-temperature applications. However, further alloy design and improvement requires a delicate balance between workability, weldability, propensity for '-phase formation, among other factors. Here, a series of advanced oxidant resistant FeCrAl alloys were produced and investigated. Variants with Al (+2%), Nb (+1%), and TiC (0.1, 0.3, and 1%) additions over the reference alloy (Fe-13%Cr-5%Al) were characterized in detail before and after controlled laser beam welding using tensile tests with digital image correlation, SEM-EBSD analysis, and fractography. All investigated alloys demonstrated yield stress in the weldment over 500 MPa; no welding-inducedmore » cracking was observed. However, it was shown that the increase in the Al-content over 5% was detrimental leading to a brittle fracture mechanism and decreased ductility in the weldment. At the same time, Nb and TiC additions were beneficial for preventing grain growth and reducing local softening (yield stress reduction) in the heat-affected zone. The 1% TiC addition also effectively refined grain size in the weldment.« less

  15. Microwaves and their coupling to advanced oxidation processes: enhanced performance in pollutants degradation.

    PubMed

    Nascimento, Ulisses M; Azevedo, Eduardo B

    2013-01-01

    This review assesses microwaves (MW) coupled to advanced oxidation processes (AOPs) for pollutants degradation, as well as the basic theory and mechanisms of MW dielectric heating. We addressed the following couplings: MW/H2O2, MW/UV/H2O2, MW/Fenton, MW/US, and MW/UV/TiO2, as well as few studies that tested alternative oxidants and catalysts. Microwave Discharge Electrodeless Lamps (MDELs) are being extensively used with great advantages over ballasts. In their degradation studies, researchers generally employed domestic ovens with minor adaptations. Non-thermal effects and synergies between UV and MW radiation play an important role in the processes. Published papers so far report degradation enhancements between 30 and 1,300%. Unfortunately, how microwaves enhance pollutants is still obscure and real wastewaters scarcely studied. Based on the results surveyed in the literature, MW/AOPs are promising alternatives for treating/remediating environmental pollutants, whenever one considers high degradation yields, short reaction times, and small costs.

  16. Amorphous mixed-metal hydroxide nanostructures for advanced water oxidation catalysts.

    PubMed

    Gao, Y Q; Liu, X Y; Yang, G W

    2016-03-07

    The design of highly efficient, durable, and earth-abundant catalysts for the oxygen evolution reaction (OER) is crucial in order to promote energy conversion and storage processes. Here, we synthesize amorphous mixed-metal (Ni-Fe) hydroxide nanostructures with a homogeneous distribution of Ni/Fe as well as a tunable Ni/Fe ratio by a simple, facile, green and low-cost electrochemical technique, and we demonstrate that the synthesized amorphous nanomaterials possess ultrahigh activity and super long-term cycle stability in the OER process. The amorphous Ni0.71Fe0.29(OH)x nanostructure affords a current density of 10 mA cm(-2) at an overpotential of a mere 0.296 V and a small Tafel slope of 58 mV dec(-1), while no deactivation is detected in the CV testing even up to 30 000 cycles, which suggests the promising application of these amorphous nanomaterials in electrochemical oxidation. Meanwhile, the distinct catalytic activities among these amorphous Ni-Fe hydroxide nanostructures prompts us to take notice of the composition of the alloy hydroxides/oxides when studying their catalytic properties, which opens an avenue for the rational design and controllable preparation of such amorphous nanomaterials as advanced OER electrocatalysts.

  17. Removal of artificial sweetener aspartame from aqueous media by electrochemical advanced oxidation processes.

    PubMed

    Lin, Heng; Oturan, Nihal; Wu, Jie; Sharma, Virender K; Zhang, Hui; Oturan, Mehmet A

    2017-01-01

    The degradation and mineralization of aspartame (ASP) in aqueous solution were investigated, for the first time, by electrochemical advanced oxidation processes (EAOPs) in which hydroxyl radicals were formed concomitantly in the bulk from Fenton reaction via in situ electrogenerated Fenton's reagent and at the anode surface from the water oxidation. Experiments were performed in an undivided cylindrical glass cell with a carbon-felt cathode and a Pt or boron-doped diamond (BDD) anode. The effect of Fe(2+) concentration and applied current on the degradation and mineralization kinetics of ASP was evaluated. The absolute rate constant for the reaction between ASP and OH was determined as (5.23 ± 0.02) × 10(9) M(-1) s(-1) by using the competition kinetic method. Almost complete mineralization of ASP was achieved with BDD anode at 200 mA constant current electrolysis. The formation and generation of the formed carboxylic acids (as ultimate end products before complete mineralization) and released inorganic ion were monitored by ion-exclusion high performance liquid chromatography (HPLC) and ion chromatography techniques, respectively. The global toxicity of the treated ASP solution during treatment was assessed by the Microtox(®) method using V. fischeri bacteria luminescence inhibition. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Advanced oxidation treatment of pulp mill effluent for TOC and toxicity removals.

    PubMed

    Catalkaya, Ebru Cokay; Kargi, Fikret

    2008-05-01

    Pulp mill effluent was treated by different advanced oxidation processes (AOPs) consisting of UV, UV/H2O2, TiO2-assisted photo-catalysis (UV/TiO2) and UV/H2O2/TiO2 in lab-scale reactors for total organic carbon (TOC) and toxicity removals. Effects of some operating parameters such as the initial pH, oxidant and catalyst concentrations on TOC and toxicity removals were investigated. Almost every method resulted in some degree of TOC and toxicity removal from the pulp mill effluent. However, the TiO2-assisted photo-catalysis (UV/TiO2) resulted in the highest TOC and toxicity removals under alkaline conditions when compared with the other AOPs tested. Approximately, 79.6% TOC and 94% toxicity removals were obtained by the TiO2-assisted photo-catalysis (UV/TiO2) with a titanium dioxide concentration of 0.75gl(-1) at pH 11 within 60min.

  19. Optimizing the electrical excitation of an atmospheric pressure plasma advanced oxidation process.

    PubMed

    Olszewski, P; Li, J F; Liu, D X; Walsh, J L

    2014-08-30

    The impact of pulse-modulated generation of atmospheric pressure plasma on the efficiency of organic dye degradation has been investigated. Aqueous samples of methyl orange were exposed to low temperature air plasma and the degradation efficiency was determined by absorbance spectroscopy. The plasma was driven at a constant frequency of 35kHz with a duty cycle of 25%, 50%, 75% and 100%. Relative concentrations of dissolved nitrogen oxides, pH, conductivity and the time evolution of gas phase ozone were measured to identify key parameters responsible for the changes observed in degradation efficiency. The results indicate that pulse modulation significantly improved dye degradation efficiency, with a plasma pulsed at 25% duty showing a two-fold enhancement. Additionally, pulse modulation led to a reduction in the amount of nitrate contamination added to the solution by the plasma. The results clearly demonstrate that optimization of the electrical excitation of the plasma can enhance both degradation efficiency and the final water quality.

  20. Responses to oxidative and heavy metal stresses in cyanobacteria: recent advances.

    PubMed

    Cassier-Chauvat, Corinne; Chauvat, Franck

    2014-12-31

    Cyanobacteria, the only known prokaryotes that perform oxygen-evolving photosynthesis, are receiving strong attention in basic and applied research. In using solar energy, water, CO2 and mineral salts to produce a large amount of biomass for the food chain, cyanobacteria constitute the first biological barrier against the entry of toxics into the food chain. In addition, cyanobacteria have the potential for the solar-driven carbon-neutral production of biofuels. However, cyanobacteria are often challenged by toxic reactive oxygen species generated under intense illumination, i.e., when their production of photosynthetic electrons exceeds what they need for the assimilation of inorganic nutrients. Furthermore, in requiring high amounts of various metals for growth, cyanobacteria are also frequently affected by drastic changes in metal availabilities. They are often challenged by heavy metals, which are increasingly spread out in the environment through human activities, and constitute persistent pollutants because they cannot be degraded. Consequently, it is important to analyze the protection against oxidative and metal stresses in cyanobacteria because these ancient organisms have developed most of these processes, a large number of which have been conserved during evolution. This review summarizes what is known regarding these mechanisms, emphasizing on their crosstalk.

  1. Responses to Oxidative and Heavy Metal Stresses in Cyanobacteria: Recent Advances

    PubMed Central

    Cassier-Chauvat, Corinne; Chauvat, Franck

    2014-01-01

    Cyanobacteria, the only known prokaryotes that perform oxygen-evolving photosynthesis, are receiving strong attention in basic and applied research. In using solar energy, water, CO2 and mineral salts to produce a large amount of biomass for the food chain, cyanobacteria constitute the first biological barrier against the entry of toxics into the food chain. In addition, cyanobacteria have the potential for the solar-driven carbon-neutral production of biofuels. However, cyanobacteria are often challenged by toxic reactive oxygen species generated under intense illumination, i.e., when their production of photosynthetic electrons exceeds what they need for the assimilation of inorganic nutrients. Furthermore, in requiring high amounts of various metals for growth, cyanobacteria are also frequently affected by drastic changes in metal availabilities. They are often challenged by heavy metals, which are increasingly spread out in the environment through human activities, and constitute persistent pollutants because they cannot be degraded. Consequently, it is important to analyze the protection against oxidative and metal stresses in cyanobacteria because these ancient organisms have developed most of these processes, a large number of which have been conserved during evolution. This review summarizes what is known regarding these mechanisms, emphasizing on their crosstalk. PMID:25561236

  2. Development of Nonalcoholic Hepatopathy: Contributions of Oxidative Stress and Advanced Glycation End Products

    PubMed Central

    Santos, Juliana Célia de F.; Valentim, Iara B.; de Araújo, Orlando R. P.; Ataide, Terezinha da R.; Goulart, Marília O. F.

    2013-01-01

    Advanced glycation end products (AGEs) are generated spontaneously in cells; however, under conditions of hyperglycemia and lipid peroxidation, their levels are higher than usual, which contribute to the development of diseases such as the nonalcoholic fatty liver disease (NAFLD). NAFLD is associated with oxidative stress (OS), which is linked to the transition of steatosis to steatohepatitis due to lipid peroxidation. The AGE-receptor interaction in hepatic stellate cells leads to an increase in reactive oxygen species and enhances the proliferation and activation of these cells, worsening liver fibrosis and disease progression. In this vicious cycle, there is production of (carboxymethyl)lysine, a biomarker for products of advanced glycation and lipid peroxidation, being a shared component between the two pathways. In this review, we aim to compile evidence to support the basic molecular mechanisms of AGEs and OS generation and their influence, independently or combined, on the evolution of NAFLD. The deeper understanding of the interrelations of AGEs + OS may help to elucidate the pathogenic pathways of NAFLD and to devise rational therapeutic interventions for this disease, with an expected positive impact on quality of life of patients. PMID:24084729

  3. Recent Advances in Superparamagnetic Iron Oxide Nanoparticles for Cellular Imaging and Targeted Therapy Research

    PubMed Central

    Wang, Yi-Xiang J.; Xuan, Shouhu; Port, Marc; Idee, Jean-Marc

    2013-01-01

    Advances of nanotechnology have led to the development of nanomaterials with both potential diagnostic and therapeutic applications. Among them, superparamagnetic iron oxide (SPIO) nanoparticles have received particular attention. Over the past decade, various SPIOs with unique physicochemical and biological properties have been designed by modifying the particle structure, size and coating. This article reviews the recent advances in preparing SPIOs with novel properties, the way these physicochemical properties of SPIOs influence their interaction with cells, and the development of SPIOs in liver and lymph nodes magnetic resonance imaging (MRI) contrast. Cellular uptake of SPIO can be exploited in a variety of potential clinical applications, including stem cell and inflammation cell tracking and intra-cellular drug delivery to cancerous cells which offers higher intra-cellular concentration. When SPIOs are used as carrier vehicle, additional advantages can be achieved including magnetic targeting and hyperthermia options, as well as monitoring with MRI. Other potential applications of SPIO include magnetofection and gene delivery, targeted retention of labeled stem cells, sentinel lymph nodes mapping, and magnetic force targeting and cell orientation for tissue engineering. PMID:23621536

  4. Insights into real cotton-textile dyeing wastewater treatment using solar advanced oxidation processes.

    PubMed

    Soares, Petrick A; Silva, Tânia F C V; Manenti, Diego R; Souza, Selene M A G U; Boaventura, Rui A R; Vilar, Vítor J P

    2014-01-01

    Different advanced oxidation processes (AOPs) were applied to the treatment of a real cotton-textile dyeing wastewater as a pre-oxidation step to enhance the biodegradability of the recalcitrant compounds, which can be further oxidized using a biological process. Tests were conducted on a lab-scale prototype using artificial solar radiation and at pilot scale with compound parabolic collectors using natural solar radiation. The cotton-textile dyeing wastewater presents a lilac color, with a maximum absorbance peak at 641 nm, alkaline pH (pH = 8.2), moderate organic content (DOC = 152 mg C L(-1), COD = 684 mg O2 L(-1)) and low-moderate biodegradability (40 % after 28 days in Zahn-Wellens test). All the tested processes contributed to an effective decolorization and mineralization, but the most efficient process was the solar-photo-Fenton with an optimum catalyst concentration of 60 mg Fe(2+) L(-1), leading to 98.5% decolorization and 85.5% mineralization after less than 0.1 and 5.8 kJUV L(-1), respectively. In order to achieve a final wastewater with a COD below 250 mg O2 L(-1) (discharge limit into water bodies imposed by the Portuguese Legislation-Portaria no. 423/97 of 25 June 1997), considering the combination of a solar-photo-Fenton reaction with a biological process, the phototreatment energy required is 0.5 kJUV L(-1), consuming 7.5 mM hydrogen peroxide, resulting in 58.4% of mineralization [Formula: see text].

  5. Decomposition of two haloacetic acids in water using UV radiation, ozone and advanced oxidation processes.

    PubMed

    Wang, Kunping; Guo, Jinsong; Yang, Min; Junji, Hirotsuji; Deng, Rongsen

    2009-03-15

    The decomposition of two haloacetic acids (HAAs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), from water was studied by means of single oxidants: ozone, UV radiation; and by the advanced oxidation processes (AOPs) constituted by combinations of O(3)/UV radiation, H(2)O(2)/UV radiation, O(3)/H(2)O(2), O(3)/H(2)O(2)/UV radiation. The concentrations of HAAs were analyzed at specified time intervals to elucidate the decomposition of HAAs. Single O(3) or UV did not result in perceptible decomposition of HAAs within the applied reaction time. O(3)/UV showed to be more suitable for the decomposition of DCAA and TCAA in water among the six methods of oxidation. Decomposition of DCAA was easier than TCAA by AOPs. For O(3)/UV in the semi-continuous mode, the effective utilization rate of ozone for HAA decomposition decreased with ozone addition. The kinetics of HAAs decomposition by O(3)/UV and the influence of coexistent humic acids and HCO(3)(-) on the decomposition process were investigated. The decomposition of the HAAs by the O(3)/UV accorded with the pseudo-first-order mode under the constant initial dissolved O(3) concentration and fixed UV radiation. The pseudo-first-order rate constant for the decomposition of DCAA was more than four times that for TCAA. Humic acids can cause the H(2)O(2) accumulation and the decrease in rate constants of HAAs decomposition in the O(3)/UV process. The rate constants for the decomposition of DCAA and TCAA decreased by 41.1% and 23.8%, respectively, when humic acids were added at a concentration of 1.2mgTOC/L. The rate constants decreased by 43.5% and 25.9%, respectively, at an HCO(3)(-) concentration of 1.0mmol/L.

  6. Inhibition of oxidative phosphorylation suppresses the development of osimertinib resistance in a preclinical model of EGFR-driven lung adenocarcinoma.

    PubMed

    Martin, Matthew J; Eberlein, Cath; Taylor, Molly; Ashton, Susan; Robinson, David; Cross, Darren

    2016-12-27

    Metabolic plasticity is an emerging hallmark of cancer, and increased glycolysis is often observed in transformed cells. Small molecule inhibitors that target driver oncogenes can potentially inhibit the glycolytic pathway. Osimertinib (AZD9291) is a novel EGFR tyrosine kinase inhibitor (TKI) that is potent and selective for sensitising (EGFRm) and T790M resistance mutations. Clinical studies have shown osimertinib to be efficacious in patients with EGFRm/ T790M advanced NSCLC who have progressed after EGFR-TKI treatment. However experience with targeted therapies suggests that acquired resistance may emerge. Thus there is a need to characterize resistance mechanisms and to devise ways to prevent, delay or overcome osimertinib resistance. We show here that osimertinib suppresses glycolysis in parental EGFR-mutant lung adenocarcinoma lines, but has not in osimertinib-resistant cell lines. Critically, we show osimertinib treatment induces a strict dependence on mitochondrial oxidative phosphorylation (OxPhos), as OxPhos inhibitors significantly delay the long-term development of osimertinib resistance in osimertinib-sensitive lines. Accordingly, growth conditions which promote a less glycolytic phenotype confer a degree of osimertinib resistance. Our data support a model in which the combination of osimertinib and OxPhos inhibitors can delay or prevent resistance in osimertinib-naïve tumour cells, and represents a novel strategy that warrants further pre-clinical investigation.

  7. Inhibition of oxidative phosphorylation suppresses the development of osimertinib resistance in a preclinical model of EGFR-driven lung adenocarcinoma

    PubMed Central

    Martin, Matthew J.; Eberlein, Cath; Taylor, Molly; Ashton, Susan; Robinson, David; Cross, Darren

    2016-01-01

    Metabolic plasticity is an emerging hallmark of cancer, and increased glycolysis is often observed in transformed cells. Small molecule inhibitors that target driver oncogenes can potentially inhibit the glycolytic pathway. Osimertinib (AZD9291) is a novel EGFR tyrosine kinase inhibitor (TKI) that is potent and selective for sensitising (EGFRm) and T790M resistance mutations. Clinical studies have shown osimertinib to be efficacious in patients with EGFRm/ T790M advanced NSCLC who have progressed after EGFR-TKI treatment. However experience with targeted therapies suggests that acquired resistance may emerge. Thus there is a need to characterize resistance mechanisms and to devise ways to prevent, delay or overcome osimertinib resistance. We show here that osimertinib suppresses glycolysis in parental EGFR-mutant lung adenocarcinoma lines, but has not in osimertinib-resistant cell lines. Critically, we show osimertinib treatment induces a strict dependence on mitochondrial oxidative phosphorylation (OxPhos), as OxPhos inhibitors significantly delay the long-term development of osimertinib resistance in osimertinib-sensitive lines. Accordingly, growth conditions which promote a less glycolytic phenotype confer a degree of osimertinib resistance. Our data support a model in which the combination of osimertinib and OxPhos inhibitors can delay or prevent resistance in osimertinib-naïve tumour cells, and represents a novel strategy that warrants further pre-clinical investigation. PMID:27861144

  8. Manufacture and engine test of advanced oxide dispersion strengthened alloy turbine vanes. [for space shuttle thermal protection

    NASA Technical Reports Server (NTRS)

    Bailey, P. G.

    1977-01-01

    Oxide-Dispersion-strengthened (ODS) Ni-Cr-Al alloy systems were exploited for turbine engine vanes which would be used for the space shuttle thermal protection system. Available commercial and developmental advanced ODS alloys were evaluated, and three were selected based on established vane property goals and manufacturing criteria. The selected alloys were evaluated in an engine test. Candidate alloys were screened by strength, thermal fatigue resistance, oxidation and sulfidation resistance. The Ni-16Cr (3 to 5)Al-ThO2 system was identified as having attractive high temperature oxidation resistance. Subsequent work also indicated exceptional sulfidation resistance for these alloys.

  9. Advanced H2O2 oxidation for diethyl phthalate degradation in treated effluents: effect of nitrate on oxidation and a pilot-scale AOP operation.

    PubMed

    Ko, K B; Park, C G; Moon, T H; Ahn, Y H; Lee, J K; Ahn, K H; Park, J H; Yeom, I T

    2008-01-01

    One of the objectives of this study was to delineate the effect of nitrate on diethyl phthalate (DEP) oxidation by conducting a bench-scale ultraviolet (UV)/H2O2 and O3/H2O2 operations as suggested in a previous study. We also aim to investigate DEP oxidation at various UV doses and H2O2 concentrations by performing a pilot-scale advanced oxidation processes (AOP) system, into which a portion of the effluent from a pilot-scale membrane bioreactor (MBR) plant was pumped. In the bench-scale AOP operation, the O3 oxidation alone as well as the UV irradiation without H2O2 addition could be among the desirable alternatives for the efficient removal of DEP dissolved in aqueous solutions at a low DEP concentration range of 85+/-15 microg/L. The adverse effect in the UV/H2O2 process was significantly greater than that in the UV oxidation alone, and its oxidation was almost halved by the nitrate. However, the nitrate clearly enhanced the DEP oxidation in the O3 oxidation and O3/H2O2 process. Especially, the addition of nitrate almost doubled the DEP oxidation efficiency in the O3/H2O2 process. The series of pilot-scale AOP operations confirmed that about 30-50% of DEP dissolved in the treated MBR effluent streams was, at least, oxidized by the O3 oxidation alone as well as the UV irradiation without H2O2 addition. The UV photolysis of H2O2 was most effective for DEP degradation with an H2O2 concentration of 40 mg/L at a UV dose of 500 mJ/cm2.

  10. Advanced oxidation protein products are more related to metabolic syndrome components than biomarkers of lipid peroxidation.

    PubMed

    Venturini, Danielle; Simão, Andréa Name Colado; Dichi, Isaias

    2015-09-01

    Although advanced oxidation protein products (AOPPs) have been reported as the most appropriate parameter for determination of oxidative stress in patients with metabolic syndrome (MetS), a direct comparison between protein and lipid peroxidation has not been performed yet. The aim of this study was to compare protein peroxidation with lipid peroxidation measured by 2 different methodologies (tert-butyl hydroperoxide-initiated chemiluminescence and ferrous oxidation-xylenol orange assay). The hypothesis of this study was that AOPPs would be more related to MetS than to oxidative markers of lipid peroxidation. This cross-sectional study evaluated 76 patients with MetS and 20 healthy subjects. Prooxidant-antioxidant index (PAI) assessed as AOPP/total radical-trapping antioxidant parameter ratio progressively increased (P < .05) according to the number of MetS components, whereas AOPPs and total radical-trapping antioxidant parameter increased (P < .05) when 5 components were compared with 3 components. Spearman test showed a positive correlation between AOPPs and waist circumference (r = 0.318, P < .01), fasting glucose (r = 0.250, P < .05), homeostasis model assessment insulin resistance (r = 0.043, P < .01), triacylglycerol (r = 0.713, P < .0001), highly sensitive C-reactive protein (r = 0.275, P < .05), and uric acid (r = 0.356, P < .01), whereas there was an inverse correlation with high-density lipoprotein cholesterol (r = -0.399, P < .001). Prooxidant-antioxidant index demonstrated a positive correlation with waist circumference (r = 0.386, P < .01), fasting glucose (r = 0.388, P < .01), fasting insulin (r = 0.344, P < .05), homeostasis model assessment insulin resistance (r = 0.519, P < .001), triacylglycerol (r = 0.687, P < .0001), highly sensitive C-reactive protein (r = 0.278, P < .05), and uric acid (r = 0.557, P < .0001), whereas there was an inverse correlation with high-density lipoprotein cholesterol (r = -0.480, P < .0001). In conclusion, protein

  11. Advanced TEM characterization of oxide nanoparticles in ODS Fe–12Cr–5Al alloys

    SciTech Connect

    Unocic, Kinga A; Hoelzer, David T; Pint, Bruce A

    2016-01-01

    For oxide nanoparticles present in three oxide-dispersion-strengthened (ODS) Fe–12Cr–5Al alloys containing additions of (1) Y2O3 (125Y), (2) Y2O3 + ZrO2 (125YZ), and (3) Y2O3 + HfO2 (125YH), were investigated using transmission and scanning transmission electron microscopy. Furthermore, in all three alloys nano-sized (<3.5 nm) oxide particles distributed uniformly throughout the microstructure were characterized using advanced electron microscopy techniques. In the 125Y alloy, mainly Al2O3 and yttrium–aluminum garnet (YAG) phases (Y3Al5O12) were present, while in the 125YZ alloy, additional Zr(C,N) precipitates were identified. The 125YH alloy had the most complex precipitation sequence whereby in addition to the YAG and Al2O3 phases, Hf(C,N), Y2Hf2O7, and HfO2 precipitates were also found. The presence of HfO2 was mainly due to the incomplete incorporation of HfO2 powder during mechanical alloying of the 125YH alloy. The alloy having the highest total number density of the oxides, the smallest grain size, and the highest Vickers hardness was the 125YZ alloy indicating, that Y2O3 + ZrO2 additions had the strongest effect on grain size and tensile properties. Finally, high-temperature mechanical testing will be addressed in the near future, while irradiation studies are underway to investigate the irradiation resistance of these new ODS FeCrAl alloys.

  12. Effect Of Inorganic, Synthetic And Naturally Occurring Chelating Agents On Fe(II) Mediated Advanced Oxidation Of Chlorophenols

    EPA Science Inventory

    This study examines the feasibility and application of Advanced Oxidation Technologies (AOTs) for the treatment of chlorophenols that are included in US EPA priority pollutant list. A novel class of sulfate/hydroxyl radical-based homogeneous AOTs (Fe(II)/PS, Fe(II)/PMS, Fe(II)/H...

  13. ADVANCED OXIDATION PROCESSES (AOPS) FOR DESTRUCTION OF METHYL TERTIARY BUTYL ETHER (MTBE -AN UNREGULATED CONTAMINANT) IN DRINKING WATER

    EPA Science Inventory

    Advanced oxidation processes (AOPs) provide a promising treatment option for the destruction of MTBE directly in surface and ground waters. An ongoing study is evaluating the ability of three AOPs; hydrogen peroxide/ozone (H2O2/ O3), ultraviolet irradiation/ozone (UV/O3) and ultr...

  14. Effect Of Inorganic, Synthetic And Naturally Occurring Chelating Agents On Fe(II) Mediated Advanced Oxidation Of Chlorophenols

    EPA Science Inventory

    This study examines the feasibility and application of Advanced Oxidation Technologies (AOTs) for the treatment of chlorophenols that are included in US EPA priority pollutant list. A novel class of sulfate/hydroxyl radical-based homogeneous AOTs (Fe(II)/PS, Fe(II)/PMS, Fe(II)/H...

  15. ADVANCED OXIDATION PROCESSES (AOPS) FOR DESTRUCTION OF METHYL TERTIARY BUTYL ETHER (MTBE -AN UNREGULATED CONTAMINANT) IN DRINKING WATER

    EPA Science Inventory

    Advanced oxidation processes (AOPs) provide a promising treatment option for the destruction of MTBE directly in surface and ground waters. An ongoing study is evaluating the ability of three AOPs; hydrogen peroxide/ozone (H2O2/ O3), ultraviolet irradiation/ozone (UV/O3) and ultr...

  16. Mission-Driven Expected Impact: Assessing Scholarly Output for 2013 Association to Advance Collegiate Schools of Business Standards

    ERIC Educational Resources Information Center

    Goulet, Laurel R.; Lopes, Kevin J.; White, John Bryan

    2016-01-01

    As of the 2016-2017 academic year, all schools undergoing Association to Advance Collegiate Schools of Business accreditation will be assessed on the new standards that were ratified in 2013, which include the assessment of the impact of portfolios of intellectual contributions. The authors discuss key ideas underlying a business school's research…

  17. Mission-Driven Expected Impact: Assessing Scholarly Output for 2013 Association to Advance Collegiate Schools of Business Standards

    ERIC Educational Resources Information Center

    Goulet, Laurel R.; Lopes, Kevin J.; White, John Bryan

    2016-01-01

    As of the 2016-2017 academic year, all schools undergoing Association to Advance Collegiate Schools of Business accreditation will be assessed on the new standards that were ratified in 2013, which include the assessment of the impact of portfolios of intellectual contributions. The authors discuss key ideas underlying a business school's research…

  18. Temperature-Driven Structural and Morphological Evolution of Zinc Oxide Nano-Coalesced Microstructures and Its Defect-Related Photoluminescence Properties.

    PubMed

    Lim, Karkeng; Abdul Hamid, Muhammad Azmi; Shamsudin, Roslinda; Al-Hardan, N H; Mansor, Ishak; Chiu, Weesiong

    2016-04-20

    In this paper, we address the synthesis of nano-coalesced microstructured zinc oxide thin films via a simple thermal evaporation process. The role of synthesis temperature on the structural, morphological, and optical properties of the prepared zinc oxide samples was deeply investigated. The obtained photoluminescence and X-ray photoelectron spectroscopy outcomes will be used to discuss the surface structure defects of the prepared samples. The results indicated that the prepared samples are polycrystalline in nature, and the sample prepared at 700 °C revealed a tremendously c-axis oriented zinc oxide. The temperature-driven morphological evolution of the zinc oxide nano-coalesced microstructures was perceived, resulting in transformation of quasi-mountain chain-like to pyramidal textured zinc oxide with increasing the synthesis temperature. The results also impart that the sample prepared at 500 °C shows a higher percentage of the zinc interstitial and oxygen vacancies. Furthermore, the intensity of the photoluminescence emission in the ultraviolet region was enhanced as the heating temperature increased from 500 °C to 700 °C. Lastly, the growth mechanism of the zinc oxide nano-coalesced microstructures is discussed according to the reaction conditions.

  19. Fluctuations in Ammonia Oxidizing Communities Across Agricultural Soils are Driven by Soil Structure and pH.

    PubMed

    Pereira E Silva, Michele C; Poly, Frank; Guillaumaud, Nadine; van Elsas, Jan Dirk; Salles, Joana Falcão

    2012-01-01

    The milieu in soil in which microorganisms dwell is never constant. Conditions such as temperature, water availability, pH and nutrients frequently change, impacting the overall functioning of the soil system. To understand the effects of such factors on soil functioning, proxies (indicators) of soil function are needed that, in a sensitive manner, reveal normal amplitude of variation. Thus, the so-called normal operating range (NOR) of soil can be defined. In this study we determined different components of nitrification by analyzing, in eight agricultural soils, how the community structures and sizes of ammonia oxidizing bacteria and archaea (AOB and AOA, respectively), and their activity, fluctuate over spatial and temporal scales. The results indicated that soil pH and soil type are the main factors that influence the size and structure of the AOA and AOB, as well as their function. The nitrification rates varied between 0.11 ± 0.03 μgN h(-1) gdw(-1) and 1.68 ± 0.11 μgN h(-1) gdw(-1), being higher in soils with higher clay content (1.09 ± 0.12 μgN h(-1) gdw(-1)) and lower in soils with lower clay percentages (0.27 ± 0.04 μgN h(-1) gdw(-1)). Nitrifying activity was driven by soil pH, mostly related to its effect on AOA but not on AOB abundance. Regarding the influence of soil parameters, clay content was the main soil factor shaping the structure of both the AOA and AOB communities. Overall, the potential nitrifying activities were higher and more variable over time in the clayey than in the sandy soils. Whereas the structure of AOB fluctuated more (62.7 ± 2.10%) the structure of AOA communities showed lower amplitude of variation (53.65 ± 3.37%). Similar trends were observed for the sizes of these communities. The present work represents a first step toward defining a NOR for soil nitrification. The sensitivity of the process and organisms to impacts from the milieu support their use as proxies in the

  20. In Situ Atomic Scale Visualization Of Surface Kinetics Driven Dynamics Of Oxide Growth On A Ni–Cr Surface

    SciTech Connect

    Luo, Langli; Zou, Lianfeng; Schreiber, Daniel K.; Olszta, Matthew J.; Baer, Donald R.; Bruemmer, Stephen M.; Zhou, Guangwen; Wang, Chong M.

    2016-01-20

    We report in situ atomic-scale visualization of the dynamical three-dimensional (3D) growth of NiO during initial oxidation of Ni-10at%Cr using environmental transmission electron microscopy (ETEM). Despite the thermodynamic preference for Cr2O3 formation, cubic NiO oxides nucleated and grew epitaxially as the dominating oxide phase on the Ni-Cr (100) surface during initial oxidation. The growth of NiO islands proceeds through step-by-step adatom mechanism in 3D, which is sustained by surface diffusion of Ni and O atoms. Although the shapes of oxide islands are controlled by strain energy between oxide and alloy substrate, local surface kinetic variations can lead to the change of surface planes of oxide islands. These results demonstrate that surface diffusion dominates initial oxidation of Ni-Cr in these test conditions.

  1. Application of advanced oxidation processes for cleaning of industrial water generated in wet dedusting of shaft furnace gases.

    PubMed

    Czaplicka, Marianna; Kurowski, Ryszard; Jaworek, Katarzyna; Bratek, Łukasz

    2013-01-01

    The paper presents results of studies into advanced oxidation processes in 03 and 03/UV systems. An advanced oxidation process (AOP) was conducted to reduce the load of impurities in circulating waters from wet de-dusting of shaft furnace gases. Besides inorganic impurities, i.e. mainly arsenic compounds (16 g As L(-1) on average), lead, zinc, chlorides and sulphates, the waters also contain some organic material. The organic material is composed of a complex mixture that contains, amongst others, aliphatic compounds, phenol and its derivatives, pyridine bases, including pyridine, and its derivatives. The test results show degradation of organic and inorganic compounds during ozonation and photo-oxidation processes. Analysis of the solutions from the processes demonstrated that the complex organic material in the industrial water was oxidized in ozonation and in photo-oxidation, which resulted in formation of aldehydes and carboxylic acids. Kinetic degradation of selected pollutants is presented. Obtained results indicated that the O3/UV process is more effective in degradation of organic matter than ozonation. Depending on the process type, precipitation of the solid phase was observed. The efficiency of solid-phase formation was higher in photo-oxidation with ozone. It was found that the precipitated solid phase is composed mainly of arsenic, iron and oxygen.

  2. Optimization of stabilized leachate treatment using ozone/persulfate in the advanced oxidation process

    SciTech Connect

    Abu Amr, Salem S.; Aziz, Hamidi Abdul; Adlan, Mohd Nordin

    2013-06-15

    Highlights: ► Ozone and persulfate reagent (O{sub 3}/S{sub 2}O{sub 8}{sup 2-}) was used to treat stabilized leachate. ► Central composite design (CCD) with response surface methodology (RSM) was applied. ► Operating variables including ozone and persulfate dosage, pH variance, and reaction time. ► Optimum removal of COD, color, and NH{sub 3}–N was 72%, 96%, and 76%, respectively. ► A good value of ozone consumption (OC) obtained with 0.60 (kg O{sub 3}/kg COD). - Abstract: The objective of this study was to investigate the performance of employing persulfate reagent in the advanced oxidation of ozone to treat stabilized landfill leachate in an ozone reactor. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as ozone and persulfate dosages, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following four responses proved to be significant with very low probabilities (<0.0001): COD, color, NH{sub 3}–N, and ozone consumption (OC). The obtained optimum conditions included a reaction time of 210 min, 30 g/m{sup 3} ozone, 1 g/1 g COD{sub 0}/S{sub 2}O{sub 8}{sup 2-} ratio, and pH 10. The experimental results were corresponded well with predicted models (COD, color, and NH{sub 3}–N removal rates of 72%, 96%, and 76%, respectively, and 0.60 (kg O{sub 3}/kg COD OC). The results obtained in the stabilized leachate treatment were compared with those from other treatment processes, such as ozone only and persulfate S{sub 2}O{sub 8}{sup 2-} only, to evaluate its effectiveness. The combined method (i.e., O{sub 3}/S{sub 2}O{sub 8}{sup 2-}) achieved higher removal efficiencies for COD, color, and NH{sub 3}–N compared with other studied applications. Furthermore, the new method is more efficient than ozone/Fenton in advanced oxidation process in the treatment of the same studied leachate.

  3. Advanced glycation end products accelerate rat vascular calcification through RAGE/oxidative stress.

    PubMed

    Wei, Qin; Ren, Xiaomei; Jiang, Yibo; Jin, Hong; Liu, Naifeng; Li, Jie

    2013-03-05

    Arterial media calcification (AMC) is highly prevalent and is a major cause of morbidity, mortality, stroke and amputation in patients with diabetes mellitus (DM). Previous research suggests that advanced glycation end products (AGEs) are responsible for vascular calcification in diabetic patients. The potential link between oxidative stress and AGEs-induced vascular calcification, however, has not been examined. Male Wistar rats received a high fat diet for 8 weeks followed by a single dose of streptozotocin to induce DM (DM). Calcification was induced with Vitamin D3 and nicotine (VDN). We started VDN treatment at 1 week after the initial streptozotocin injection (DM+VDN). Age-matched rats were used as controls (CON). Metabolic parameters, aortic calcium content, alkaline phosphatase (ALP) protein, malondialdehyde (MDA) content, Cu/Zn superoxide dismutase (SOD) activity, aorta receptor for advanced glycation end products (RAGE) and aorta AGEs levels were measured. In vitro, vascular smooth muscle cells (VSMCs) were cultured with AGEs in DMEM containing 10 mmol·L(-1) ß -glycerophosphate (ß-GP). Calcium content and ALP activity were used to identify osteoblastic differentiation and mineralization. Western blots were used to examine protein expression of Cu/Zn SOD, NADPH oxidase Nox1 and RAGE. In addition, the intracellular reactive oxygen species (ROS) generation was evaluated using fluorescent techniques with dihydroethidine (DHE) method. The DM+VDN group showed a significant increase in aortic calcium content, levels of aorta AGEs, MDA content, ALP protein levels and RAGE expression, although Cu/Zn SOD activity decreased significantly. In vitro, enhanced Nox1, RAGE expression as well as the production of intracellular superoxide anions, and reduced expression of Cu/Zn SOD induced by AGEs were attenuated by the anti-RAGE antibody or a ROS inhibitor. Furthermore, the AGEs-stimulated ROS increase was also significantly inhibited by a SOD mimetic. Increased ALP

  4. Formation of nitroaromatic compounds in advanced oxidation processes: Photolysis versus photocatalysis

    SciTech Connect

    Dzengel, J.; Theurich, J.; Bahnemann, D.W.

    1999-01-15

    There is a growing demand for efficient treatment of organic polluted wastewaters by advanced oxidation processes (AOPs). Besides optimization of the processes, the detailed understanding of degradation mechanisms and interactions of organic pollutants with inorganic substrates is important for technical applications of AOPs. Therefore, the aim of the present study was to investigate the influence of nitrate ions on the photooxidation of phenol for various AOPs at different pH values. Three different oxidation processes were compared in these studies: direct photolysis, TiO{sub 2}/UV, and H{sub 2}O{sub 2}/UV. Special emphasis has been laid on the analysis of byproducts especially on the formation of nitroaromatic compounds. The formation of intermediates as well as the depletion of phenol were monitored by HPLC technique. The total organic carbon content, TOC, was measured to monitor the mineralization. Highest degradation rates and lowest concentrations of intermediates were observed with TiO{sub 2}/UV being the AOP. Formation of highly toxic nitrophenols was only observed when homogeneous AOPs were employed. For the TiO{sub 2}/UV process no formation of Nitroaromatic byproducts occurred. At pH 5 formation of nitrophenols was observed employing direct photolysis in the presence of NO{sub 2}{sup {minus}}, while with H{sub 2}O{sub 2}/UV nitrophenols were detected only when the concentration of NO{sub 2}{sup {minus}} was higher than that of H{sub 2}O{sub 2}. At pH 11 no nitroaromatic intermediates were found for any AOPs compared in this study.

  5. Advanced glycation end products, oxidative stress and metalloproteinases are altered in the cerebral microvasculature during aging.

    PubMed

    Safciuc, Florentina; Constantin, Alina; Manea, Adrian; Nicolae, Manuela; Popov, Doina; Raicu, Monica; Alexandru, Dorin; Constantinescu, Elena

    2007-11-01

    Biological aging is associated with an increased incidence of cerebrovascular disease. Recent findings indicate that oxidative stress promoting age-related changes of cerebral circulation are involved in neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease. The aim of this study was to evaluate the contribution of cerebral microvessels to the oxidative stress during brain aging, by: (i) assessment of precursors for advanced glycation end products (AGE) formation, (ii) activities of antioxidant enzymes, namely superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione disulfide reductase (GR), and (iii) the activities of metalloproteinases (MMPs), MMP-2 and MMP-9, involved in synaptogenesis and memory consolidation. The experiments were performed on two groups of male Wistar rats: 15 young (3-6 months old) and 15 aged (18-24 months old) animals. The cerebral microvessels were isolated by mechanical homogenization, the concentration of protein carbonyls and the activity of antioxidant enzymes were evaluated by spectrophotometry, and gelatin SDS-PAGE zymography was employed to evaluate MMP-2 and MMP-9 activities. The results showed that, by comparison with young rats, aged brain microvessels contain: (i) approximately 106 % increase of protein carbonyls production; (ii) approximately 68% higher GPx activity, unmodified activities of SOD and GR; (iii) approximately 30% diminishment in MMP-2 activity, and the specific occurrence of MMP-9 enzyme. The data suggest that the age-related changes of microvessels could increase the propensity for cerebral diseases and might represent, at least in part, a prerequisite for the deterioration of mental and physical status in the elderly.

  6. Medium-high frequency ultrasound and ozone based advanced oxidation for amoxicillin removal in water.

    PubMed

    Kıdak, Rana; Doğan, Şifa

    2017-01-28

    In this study, treatment of an antibiotic compound amoxicillin by medium-high frequency ultrasonic irradiation and/or ozonation has been studied. Ultrasonic irradiation process was carried out in a batch reactor for aqueous amoxicillin solutions at three different frequencies (575, 861 and 1141kHz). The applied ultrasonic power was 75W and the diffused power was calculated as 14.6W/L. The highest removal was achieved at 575kHz ultrasonic frequency (>99%) with the highest pseudo first order reaction rate constant 0.04min(-1) at pH 10 but the mineralization achieved was around 10%. Presence of alkalinity and humic acid species had negative effect on the removal efficiency (50% decrease). To improve the poor outcomes, ozonation had been applied with or without ultrasound. Ozone removed the amoxicillin at a rate 50 times faster than ultrasound. Moreover, due to the synergistic effect, coupling of ozone and ultrasound gave rise to rate constant of 2.5min(-1) (625 times higher than ultrasound). In the processes where ozone was used, humic acid did not show any significant effect because the rate constant was so high that ozone has easily overcome the scavenging effects of natural water constituents. Furthermore, the intermediate compounds, after the incomplete oxidation mechanisms, has been analyzed to reveal the possible degradation pathways of amoxicillin through ultrasonic irradiation and ozonation applications. The outcomes of the intermediate compounds experiments and the toxicity was investigated to give a clear explanation about the safety of the resulting solution. The relevance of all the results concluded that hybrid advanced oxidation system was the best option for amoxicillin removal.

  7. Advanced treatment of wet-spun acrylic fiber manufacturing wastewater using three-dimensional electrochemical oxidation.

    PubMed

    Zheng, Tianlong; Wang, Qunhui; Shi, Zhining; Fang, Yue; Shi, Shanshan; Wang, Juan; Wu, Chuanfu

    2016-12-01

    A three-dimensional electrochemical oxidation (3D-EC) reactor with introduction of activated carbon (AC) as particle micro-electrodes was applied for the advanced treatment of secondary wastewater effluent of a wet-spun acrylic fiber manufacturing plant. Under the optimized conditions (current density of 500A/m(2), circulation rate of 5mL/min, AC dosage of 50g, and chloride concentration of 1.0g/L), the average removal efficiencies of chemical oxygen demand (CODcr), NH3-N, total organic carbon (TOC), and ultraviolet absorption at 254nm (UV254) of the 3D-EC reactor were 64.5%, 60.8%, 46.4%, and 64.8%, respectively; while the corresponding effluent concentrations of CODcr, NH3-N, TOC, and UV254 were 76.6, 20.1, and 42.5mg/L, and 0.08Abs/cm, respectively. The effluent concentration of CODcr was less than 100mg/L, which showed that the treated wastewater satisfied the demand of the integrated wastewater discharge standard (GB 8978-1996). The 3D-EC process remarkably improved the treatment efficiencies with synergistic effects for CODcr, NH3-N, TOC, and UV254 during the stable stage of 44.5%, 38.8%, 27.2%, and 10.9%, respectively, as compared with the sum of the efficiencies of a two-dimensional electrochemical oxidation (2D-EC) reactor and an AC adsorption process, which was ascribed to the numerous micro-electrodes of AC in the 3D-EC reactor. Gas chromatography mass spectrometry (GC-MS) analysis revealed that electrochemical treatment did not generate more toxic organics, and it was proved that the increase in acute biotoxicity was caused primarily by the production of free chlorine.

  8. Advanced oxidation and disinfection processes for onsite net-zero greywater reuse: A review.

    PubMed

    Gassie, Lucien W; Englehardt, James D

    2017-08-30

    Net-zero greywater (NZGW) reuse, or nearly closed-loop recycle of greywater for all original uses, can recover both water and its attendant hot-water thermal energy, while avoiding the installation and maintenance of a separate greywater sewer in residential areas. Such a system, if portable, could also provide wash water for remote emergency health care units. However, such greywater reuse engenders human contact with the recycled water, and hence superior treatment. The purpose of this paper is to review processes applicable to the mineralization of organics, including control of oxidative byproducts such as bromate, and maintenance of disinfection consistent with potable reuse guidelines, in NZGW systems. Specifically, TiO2-UV, UV-hydrogen peroxide, hydrogen peroxide-ozone, ozone-UV advanced oxidation processes, and UV, ozone, hydrogen peroxide, filtration, and chlorine disinfection processes were reviewed for performance, energy demand, environmental impact, and operational simplicity. Based on the literature reviewed, peroxone is the most energy-efficient process for organics mineralization. However, in portable applications where delivery of chemicals to the site is a concern, the UV-ozone process appears promising, at higher energy demand. In either case, reverse osmosis, nanofiltration, or ED may be useful in controlling the bromide precursor in make-up water, and a minor side-stream of ozone may be used to prevent microbial regrowth in the treated water. Where energy is not paramount, UV-hydrogen peroxide and UV-TiO2 can be used to mineralize organics while avoiding bromate formation, but may require a secondary process to prevent microbial regrowth. Chlorine and ozone may be useful for maintenance of disinfection residual. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Removal of COD from a stabilized landfill leachate by physicochemical and advanced oxidative process.

    PubMed

    Cheibub, Ana F; Campos, Juacyara C; da Fonseca, Fabiana V

    2014-01-01

    This work investigated the effectiveness of a physicochemical and oxidative process for the removal of chemical oxygen demand (COD) from stabilized landfill leachates. The application of these technologies for landfill leachate treatment greatly depends on the optimal operating conditions for a specific leachate. Coagulation-flocculation followed by H2O2, Fenton and photo-Fenton processes was evaluated. Advanced oxidation processes were evaluated in the raw leachate and the leachate pretreated by coagulation-flocculation. Via the coagulation process, at 30 sec and a stirring speed of 150 rpm followed by flocculation and settling steps, 53% COD was removed at an optimal dose of 1400 mg L(-1) and pH 4.0. Moreover, from the POA evaluated, the Fenton process was determined to be the most effective process for removing COD from the leachate pretreated by coagulation-flocculation, reaching 83.3% COD removal with 1330 mg L(-1) of H2O2 and 266 mg L(-1) of Fe(2+). The photo-Fenton process applied directly to the raw effluent was effective for the removal of COD; a 75% reduction in COD was observed in tests using 2720 mg L(-1) of H2O2 and 544 mg L(-1) of Fe(2+). Due to the variability in the composition of the Gramacho landfill leachate, the combination of coagulation-flocculation and the Fenton process is an effective technology for reducing the COD in samples of this leachate.

  10. [Effects of organic pollutants in drinking water on the removal of dimethyl phthalate by advanced oxidation processes].

    PubMed

    Rui, Min; Gao, Nai-yun; Xu, Bin; Li, Fu-sheng; Zhao, Jian-fu; Le, Lin-sheng

    2006-12-01

    Humic acids were used to simulate natural organic compounds in water for the investigation of DMP oxidation by three different AOPs (advanced oxidation processes) of UV-H2O2, O3 and UV-O3. The results showed that pseudo-first-order reaction equation could describe the oxidation of DMP by UV-H2O2 perfectly, which was strongly affected humic acids in water. The relationship between pseudo-first-order reaction rate and TOC value could be expressed as K = 0. 162 0 [TOC]-0.8171. It was also found that humic acids in the water exhibited obvious influence on the oxidation of DMP by UV-O3. However, effect of humic acids on the oxidation of DMP by ozone was not obvious. It was also analyzed that oxidation of DMP was dominated by ozone oxidation both in ozonation process and UV-O3 process; the importance of "OH in the oxidation of DMP was enhanced as the concentration of DMP decreased in UV-O3 process. The degree of impact form humic acids towards different AOPs could be ranked in a decreasing order as UV-H2O3, UV-O3, 03.

  11. Removal of atrazine and its by-products from water using electrochemical advanced oxidation processes.

    PubMed

    Komtchou, Simon; Dirany, Ahmad; Drogui, Patrick; Robert, Didier; Lafrance, Pierre

    2017-08-17

    Atrazine (ATZ) is one of the most common pesticides detected in surface water in Quebec (Canada). The present study was mainly focused on the degradation of ATZ and its by-products using electrochemical advanced oxidation processes such as photo-electro-Fenton (PEF), electro-Fenton (EF) and anodic-oxidation with simultaneous H2O2 formation (AO - H2O2). The comparison of these processes showed that PEF process was found to be the most effective process in removing ATZ and its by-products from both synthetic solution (ATZ0 = 100 μg L(-1)) and real agricultural surface water enriched with ATZ (ATZ0 = 10 μg L(-1)). Different operating parameters, including wavelength of the light, pH, current density and the presence of natural organic matter (humic acids) were investigated for PEF process using boron-doped diamond (BDD) anode and graphite cathode. The current density and the wavelength of the light were the most important parameters in the ATZ degradation efficiency. The best operating conditions were recorded for the synthetic samples at a current density of 18.2 mA cm(-2), a pH of 3.0 and treatment time of 45 min. Results showed that atrazine-desethyl-desisopropyl (DEDIA) was the most important by-product recorded. More than 99% of ATZ oxidation was recorded after 15 min of treatment and all the concentrations of major by-products were less than the limit of detection after 45 min of treatment. The PEF process was also tested for real surface water contaminated by ATZ: i) with and without addition of iron; ii) without pH adjustment (pH ∼ 6.7) and with pH adjustment (pH ∼ 3.1). In spite of the presence of radical scavenger and iron complexation the PEF process was more effective to remove ATZ from real surface water when the pH value was adjusted near to 3.0. The ATZ removal was 96.0% with 0.01 mM of iron (kapp = 0.13 min(-1)) and 100% with 0.1 mM of iron (kapp = 0.17 min(-1)). Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Dechlorination of chlorophenols found in pulp bleach plant E-1 effluents by advanced oxidation processes.

    PubMed

    Wang, Rui; Chen, Chen-Loung; Gratzl, Josef S

    2005-05-01

    Studies were conducted on the response of 2,4,6-trichlorophenol (1), 2,3,4,5-tetrachloro-phenol (2) and 4,5-dichloroguaiacol (3) toward advanced oxidation processes, such as UV-, O2/UV-, H2O2/UV-, O3/UV- and O3-H2O2/UV-photolyses with irradiation of 254 nm photons. The compounds 1-3 are among the chlorophenols found in the Kraft-pulp bleach plant E-1 effluents. The studies were extended to treatment of these compounds with ozonation and O3-H2O2 oxidation systems in alkaline aqueous solution. Except for the O2/UV-photolysis of 1 and H2O2/UV-photolysis of 2, the dechlorination of 1-3 by O2/UV- and H2O2/UV-potolyses were less effective than the corresponding N2UV-potolysis of 1-3. Guaiacol-type chlorophenols were more readily able to undergo dechlorination than non-guaiacol type chlorophenols by N2/UV-, O2/UV- and H2O2/UV-potolyses. In addition, the efficiency for the dechlorination of 1-3 by N2/UV-, O2/UV- and H2O2/UV-potolyses appeared to be dependent upon the inductive and resonance effects of substituents as well as number and position of chlorine substituent in the aromatic ring of the compounds. The dechlorination of 2 by treatment with O3 alone is slightly more effective than the corresponding the O3/UV-photlysis, whereas the dechlorination of 2 by treatment with the combination of O3 and H2O2 was slightly less effective than the corresponding O3-H2O2/UV-photolysis. In contrast, the dechlorination of 3 on treatment with O3 alone was slightly less effective than the corresponding the O3/UV-photolysis, whereas the dechlorination of 3 on treatment with the combination of O3 and H2O2 was slightly more effective than the corresponding the O3-H2O2/UV-photolysis. In the dechlorination of 2 and 3, chemical species derived from ozone and hydrogen peroxide in alkaline solution were dominant reactions in the O3/UV- and O3-H2O2/UV-photolysis systems as in the O3 and O3-H2O2 oxidation systems. Possible dechlorination mechanisms involved were discussed on the basis of

  13. Development of nanomaterial-enabled advanced oxidation techniques for treatment of organic micropollutants

    NASA Astrophysics Data System (ADS)

    Oulton, Rebekah Lynn

    Increasing demand for limited fresh water resources necessitates that alternative water sources be developed. Nonpotable reuse of treated wastewater represents one such alternative. However, the ubiquitous presence of organic micropollutants such as pharmaceuticals and personal care products (PPCPs) in wastewater effluents limits use of this resource. Numerous investigations have examined PPCP fate during wastewater treatment, focusing on their removal during conventional and advanced treatment processes. Analysis of influent and effluent data from published studies reveals that at best 1-log10 concentration unit of PPCP removal can generally be achieved with conventional treatment. In contrast, plants employing advanced treatment methods, particularly ozonation and/or membranes, remove most PPCPs often to levels below analytical detection limits. However, membrane treatment is cost prohibitive for many facilities, and ozone treatment can be very selective. Ozone-recalcitrant compounds require the use of Advanced Oxidation Processes (AOPs), which utilize highly reactive hydroxyl radicals (*OH) to target resistant pollutants. Due to cost and energy use concerns associated with current AOPs, alternatives such as catalytic ozonation are under investigation. Catalytic ozonation uses substrates such as activated carbon to promote *OH formation during ozonation. Here, we show that multi-walled carbon nanotubes (MWCNTs) represent another viable substrate, promoting *OH formation during ozonation to levels exceeding activated carbon and equivalent to conventional ozone-based AOPs. Via a series of batch reactions, we observ a strong correlation between *OH formation and MWCNT surface oxygen concentrations. Results suggest that deprotonated carboxyl groups on the CNT surface are integral to their reactivity toward ozone and corresponding *OH formation. From a practical standpoint, we show that industrial grade MWCNTs exhibit similar *OH production as their research

  14. Advanced glycation endproducts alter functions and promote apoptosis in endothelial progenitor cells through receptor for advanced glycation endproducts mediate overpression of cell oxidant stress.

    PubMed

    Chen, Jianfei; Song, Minbao; Yu, Shiyong; Gao, Pan; Yu, Yang; Wang, Hong; Huang, Lan

    2010-02-01

    Endothelial progenitor cells (EPCs) play an important role in preventing atherosclerosis. The factors that regulate the function of EPCs are not completely clear. Increased formation of advanced glycation endproducts (AGEs) is generally regarded as one of the main mechanisms responsible for vascular damage in patients with diabetes and atherosclerosis. AGEs lead to the generation of reactive oxygen species (ROS) and part of the regenerative capacity of EPCs seems to be due to their low baseline ROS levels and reduced sensitivity to ROS-induced cell apoptosis. Therefore, we tested the hypothesis that AGEs can alter functions and promote apoptosis in EPCs through overpress cell oxidant stress. EPCs, isolated from bone marrow, were cultured in the absence or presence of AGEs (50, 100, and 200 microg/ml). A modified Boyden's chamber was used to assess the migration of EPCs and the number of recultured EPCs was counted to measure the adhesiveness function. MTT assay was used to determine the proliferation function. ROS were analyzed using the ROS assay kit. A spectrophotometer was used to assess superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activity, and PCR was used to test mRNA expression of SOD and GSH-PX. SiRNA was used to block receptor for advanced glycation endproducts (RAGEs) expression. Apoptosis was evaluated by Annexin V immunostaining and TUNEL staining. Co-culturing with AGEs increases ROS production, decreases anti-oxidant defenses, overpresses oxidant stress, inhibits the proliferation, migration, and adhesion of EPCs, and induces EPCs apoptosis. In addition, these effects were attenuated during block RAGE protein expression by siRNA. AGEs may serve to impair EPCs functions through RAGE-mediate oxidant stress, and promote EPCs sensitivity toward oxidative-stress-mediated apoptosis, which indicates a new pathophysiological mechanism of disturbed vascular adaptation in atherosclerosis and suggests that lower levels of AGEs might improve the

  15. Advanced oxidation of a commercially important nonionic surfactant: investigation of degradation products and toxicity.

    PubMed

    Karci, Akin; Arslan-Alaton, Idil; Bekbolet, Miray

    2013-12-15

    The evolution of degradation products and changes in acute toxicity during advanced oxidation of the nonionic surfactant nonylphenol decaethoxylate (NP-10) with the H2O2/UV-C and photo-Fenton processes were investigated. H2O2/UV-C and photo-Fenton processes ensured complete removal of NP-10, which was accompanied by the generation of polyethylene glycols with 3-8 ethoxy units. Formation of aldehydes and low carbon carboxylic acids was evidenced. According to the acute toxicity tests carried out with Vibrio fischeri, degradation products being more inhibitory than the original NP-10 solution were formed after the H2O2/UV-C process, whereas the photo-Fenton process appeared to be toxicologically safer since acute toxicity did not increase relative to the original NP-10 solution after treatment. Temporal evolution of the acute toxicity was strongly correlated with the identified carboxylic acids being formed during the application of H2O2/UV-C and photo-Fenton processes.

  16. Recent advances in theranostic nanocarriers of doxorubicin based on iron oxide and gold nanoparticles.

    PubMed

    Gautier, J; Allard-Vannier, E; Munnier, E; Soucé, M; Chourpa, I

    2013-07-10

    Hybrid (organic/inorganic) nanoparticles emerged as a simple solution to build "theranostic" systems. Due to their physical properties, superparamagnetic iron oxide nanoparticles (SPIONs) and plasmonic gold nanoparticles (Au-NPs) are extensively studied as a part of diagnostic and therapeutic strategies in cancer treatments. They can be used as agents for in vitro or in vivo imaging, for magnetic drug targeting and/or thermal therapy. Their functionalization with organic shells enhances their potential performance in tumor targeting and drug delivery. The advances in such hybrid nanocarriers are well illustrated with the example of the anticancer drug doxorubicin (DOX). The aim of this review is to give a multidisciplinary overview of such smart nanosystems loaded with DOX, based on examples taken from recent publications. From a physico-chemical point of view, we discuss the choices for the strategies for loading DOX and the consequences on drug release. From a biological point of view, we analyze the in vitro and in vivo assays concerning tumor imaging, targeted drug delivery and anticancer efficiency. Future opportunities and challenges are also addressed. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Cork boiling wastewater treatment and reuse through combination of advanced oxidation technologies.

    PubMed

    Ponce-Robles, L; Miralles-Cuevas, S; Oller, I; Agüera, A; Trinidad-Lozano, M J; Yuste, F J; Malato, S

    2016-08-12

    Industrial preparation of cork consists of its immersion for approximately 1 hour in boiling water. The use of herbicides and pesticides in oak tree forests leads to absorption of these compounds by cork; thus, after boiling process, they are present in wastewater. Cork boiling wastewater shows low biodegradability and high acute toxicity involving partial inhibition of their biodegradation when conventional biological treatment is applied. In this work, a treatment line strategy based on the combination of advanced physicochemical technologies is proposed. The final objective is the reuse of wastewater in the cork boiling process; thus, reducing consumption of fresh water in the industrial process itself. Coagulation pre-treatment with 0.5 g/L of FeCl3 attained the highest turbidity elimination (86 %) and 29 % of DOC elimination. Similar DOC removal was attained when using 1 g/L of ECOTAN BIO (selected for ozonation tests), accompanied of 64 % of turbidity removal. Ozonation treatments showed less efficiency in the complete oxidation of cork boiling wastewater, compared to solar photo-Fenton process, under the studied conditions. Nanofiltration system was successfully employed as a final purification step with the aim of obtaining a high-quality reusable permeate stream. Monitoring of unknown compounds by LC-QTOF-MS allowed the qualitative evaluation of the whole process. Acute and chronic toxicity as well as biodegradability assays were performed throughout the whole proposed treatment line.

  18. Using advanced oxidation treatment for biofilm inactivation by varying water vapor content in air plasma

    NASA Astrophysics Data System (ADS)

    Ryota, Suganuma; Koichi, Yasuoka

    2015-09-01

    Biofilms are caused by environmental degradation in food factories and medical facilities. The inactivation of biofilms involves making them react with chemicals including chlorine, hydrogen peroxide, and ozone, although inactivation using chemicals has a potential problem because of the hazardous properties of the residual substance and hydrogen peroxide, which have slow reaction velocity. We successfully performed an advanced oxidation process (AOP) using air plasma. Hydrogen peroxide and ozone, which were used for the formation of OH radicals in our experiment, were generated by varying the amount of water vapor supplied to the plasma. By varying the content of the water included in the air, the main product was changed from air plasma. When we increased the water content in the air, hydrogen peroxide was produced, while ozone peroxide was produced when we decreased the water content in the air. By varying the amount of water vapor, we realized a 99.9% reduction in the amount of bacteria in the biofilm when we discharged humidified air only. This work was supported by JSPS KAKENHI Grant Number 25630104.

  19. Removal of disinfection by-product precursors with ozone-UV advanced oxidation process.

    PubMed

    Chin, A; Bérubé, P R

    2005-05-01

    The efficacy of using ozone (O3), ultraviolet irradiation (UV) and the combined O3-UV advanced oxidation process (AOP) to remove 2 classes of disinfection by-product (DBP) precursors from raw surface water samples have been evaluated and compared. In particular, trihalomethane and haloacetic acids formation potentials were measured. Laboratory batch scale experiments were carried out as a function of ozone and UV dosage in order to study the removal kinetics. It is concluded that the combined O3-UV AOP is more effective than either the ozone or UV treatment alone. Ozone-UV AOP is capable of mineralizing up to 50% of the total organic carbon from the raw source water at an ozone dose of 0.62+/-0.019 mg O3/mL and a UV dose of 1.61 W s/cm2. In addition, O3-UV AOP can reduce trihalomethane formation potential by roughly 80% and haloacetic acids formation potential by roughly 70% at the same ozone and UV dosage.

  20. Mechanisms of advanced oxidation processing on bentonite consumption reduction in foundry.

    PubMed

    Wang, Yujue; Cannon, Fred S; Komarneni, Sridhar; Voigt, Robert C; Furness, J C

    2005-10-01

    Prior full-scale foundry data have shown that when an advanced oxidation (AO) process is employed in a green sand system, the foundry needs 20-35% less makeup bentonite clay than when AO is not employed. We herein sought to explore the mechanism of this enhancement and found that AO water displaced the carbon coating of pyrolyzed carbonaceous condensates that otherwise accumulated on the bentonite surface. This was discerned by surface elemental analysis. This AO treatment restored the clay's capacity to adsorb methylene blue (as a measure of its surface charge) and water vapor (as a reflection of its hydrophilic character). In full-scale foundries, these parameters have been tied to improved green compressive strength and mold performance. When baghouse dust from a full-scale foundry received ultrasonic treatment in the lab, 25-30% of the dust classified into the clay-size fraction, whereas only 7% classified this way without ultrasonics. Also, the ultrasonication caused a size reduction of the bentonite due to the delamination of bentonite particles. The average bentonite particle diameter decreased from 4.6 to 3 microm, while the light-scattering surface area increased over 50% after 20 min ultrasonication. This would greatly improve the bonding efficiency of the bentonite according to the classical clay bonding mechanism. As a combined result of these mechanisms, the reduced bentonite consumption in full-scale foundries could be accounted for.

  1. Comparison of advanced oxidation processes and identification of monuron photodegradation products in aqueous solution.

    PubMed

    Bobu, Maria; Wilson, Steven; Greibrokk, Tyge; Lundanes, Elsa; Siminiceanu, Ilie

    2006-06-01

    The photodegradation of monuron (3-(4-chlorophenyl)-1,1-dimethylurea) in aqueous solutions under simulated solar irradiation has been conducted by different advanced oxidation processes (UV/H(2)O(2), UV/H(2)O(2)/Fe(2+), UV/H(2)O(2)/TiO(2), UV/TiO(2), dark H(2)O(2)/Fe(3+)). The degradation rates were always higher for the homogeneous catalysis in photo-Fenton reactions (UV/H(2)O(2)/Fe(2+)) compared to the heterogeneous photocatalytic systems (TiO(2)/UV and UV/H(2)O(2)/TiO(2)). Optimal concentrations of Fe(2+) and H(2)O(2) for the abatement of the herbicide in the photo-Fenton system were found to be 1 mM Fe(II) and 10 mM H(2)O(2). Several intermediary products were identified using large volume injection micro-liquid chromatography with UV detection (mu-LC-UV), mu-LC-MS and GC-MS techniques and a degradation mechanism has been proposed.

  2. Characteristics of Toluene Treatment by Combination of Surface Discharge and Ad-vance Oxidation Processes

    NASA Astrophysics Data System (ADS)

    Shimosaki, Mitsuaki; Hayashi, Nobuya; Yamabe, Chobei

    2004-09-01

    Recently, decomposition of the toluene has been studied using several types of discharges, and the decom-position was 70% using the surface discharge. In order to improve the decomposition rate of toluene and to con-trol byproducts, combination of surface discharges and Advanced Oxidation Process was developed for the treat-ment of volatile organic compound. The oxygen radical was generated by irradiation of ultraviolet rays (253.7 nm) to ozone, which was able to decompose toxic substances such as toluene. UV rays from UV light tube irradiated to ozone which generated by the surface discharge to generate oxygen radical. Toluene was decomposed efficiently by the surface discharge and oxygen radical. The maximum decomposition rate of toluene was achieved to be ap-proximately 98%, when discharge power exceeded 3.5 kV. Measured byproducts were water vapor, carbon monoxide, carbon dioxide and formic acid. However, formic acid was generated in the case of low discharge power (below 3 kV), it was decomposed to water, carbon monoxide and carbon dioxide, when discharge power exceeded 3 kV.

  3. Bioelectro-Fenton: evaluation of a combined biological-advanced oxidation treatment for pharmaceutical wastewater.

    PubMed

    Ganzenko, Oleksandra; Trellu, Clement; Papirio, Stefano; Oturan, Nihal; Huguenot, David; van Hullebusch, Eric D; Esposito, Giovanni; Oturan, Mehmet A

    2017-01-31

    Electro-Fenton (EF), an advanced