WorldWideScience

Sample records for cerevisiae wet oxidation

  1. Potential inhibitors from wet oxidation of wheat straw and their effect on ethanol production of Saccharomyces cerevisiae: Wet oxidation and fermentation by yeast

    DEFF Research Database (Denmark)

    Klinke, Helene Bendstrup; Olsson, Lisbeth; Thomsen, A.B.;

    2003-01-01

    concentrations of 50-100 times the concentration found in the hydrolysate for their effect on fermentation by yeast. At these high concentrations (10 mM), 4-hydroxy-benzaldehyde, vanillin, 4-hydroxyacetophenone and acetovanillone caused a 53-67% decrease in the volumetric ethanol productivity in S. cerevisiae...

  2. Wet oxidation of quinoline

    DEFF Research Database (Denmark)

    Thomsen, A.B.; Kilen, H.H.

    1998-01-01

    The influence of oxygen pressure (0.4 and 2 MPa). reaction time (30 and 60 min) and temperature (260 and 280 degrees C) on the wet oxidation of quinoline has been studied. The dominant parameters for the decomposition of quinoline were oxygen pressure and reaction temperature. whereas the reaction...... time was less important within the range studied. Nitrifying bacteria were used to measure the inhibition from wet oxidative-treated samples to study the effect of the (wet oxidation) reaction conditions. Wet oxidation made quinoline more toxic to Nitrosomonas. This was observed for Nitrobacter as well....... The combined wet oxidation and biological treatment of reaction products resulted in 91% oxidation of the parent compound to CO2 and water. Following combined wet oxidation and biological treatment the sample showed low toxicity towards Nitrosomonas and no toxicity towards Nitrobacter. (C) 1998 Elsevier...

  3. Potential inhibitors from wet oxidation of wheat straw and their effect on ethanol production of Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Klinke, H.B.; Olsson, L.; Thomsen, A.B.;

    2003-01-01

    concentrations of 50-100 times the concentration found in the hydrolysate for their effect on fermentation by yeast. At these high concentrations (10 mM), 4-hydroxy-benzaldehyde, vanillin, 4-hydroxyacetophenone and acetovanillone caused a 53-67% decrease in the volumetric ethanol productivity in S. cerevisiae...

  4. Inhibiting Wet Oxidation of Ammonia

    Science.gov (United States)

    Onisko, D. B. L.

    1985-01-01

    Simple modification of wet-oxidation process for treating organicwaste reduces loss of fixed nitrogen, potentially valuable byproduct of process. Addition of sufficient sulfuric acid to maintain reaction pH below 3 greatly reduces oxidation of ammonia to free nitrogen. No equipment modification required.

  5. Coal combustion by wet oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Bettinger, J.A.; Lamparter, R.A.; McDowell, D.C.

    1980-11-15

    The combustion of coal by wet oxidation was studied by the Center for Waste Management Programs, of Michigan Technological University. In wet oxidation a combustible material, such as coal, is reacted with oxygen in the presence of liquid water. The reaction is typically carried out in the range of 204/sup 0/C (400/sup 0/F) to 353/sup 0/C (650/sup 0/F) with sufficient pressure to maintain the water present in the liquid state, and provide the partial pressure of oxygen in the gas phase necessary to carry out the reaction. Experimental studies to explore the key reaction parameters of temperature, time, oxidant, catalyst, coal type, and mesh size were conducted by running batch tests in a one-gallon stirred autoclave. The factors exhibiting the greatest effect on the extent of reaction were temperature and residence time. The effect of temperature was studied from 204/sup 0/C (400/sup 0/F) to 260/sup 0/C (500/sup 0/F) with a residence time from 600 to 3600 seconds. From this data, the reaction activation energy of 2.7 x 10/sup 4/ calories per mole was determined for a high-volatile-A-Bituminous type coal. The reaction rate constant may be determined at any temperature from the activation energy using the Arrhenius equation. Additional data were generated on the effect of mesh size and different coal types. A sample of peat was also tested. Two catalysts were evaluated, and their effects on reaction rate presented in the report. In addition to the high temperature combustion, low temperature desulfurization is discussed. Desulfurization can improve low grade coal to be used in conventional combustion methods. It was found that 90% of the sulfur can be removed from the coal by wet oxidation with the carbon untouched. Further desulfurization studies are indicated.

  6. Mechanisms of wet oxidation by hydrogen peroxide

    International Nuclear Information System (INIS)

    A research programme is currently under way at BNL and MEL to investigate the possible use of Hydrogen Peroxide with metal ion catalysts as a wet oxidation treatment system for CEGB organic radioactive wastes. The published literature relating to the kinetics and mechanism of oxidation and decomposition reactions of hydrogen peroxide is reviewed and the links with practical waste management by wet oxidation are examined. Alternative wet oxidation systems are described and the similarities to the CEGB research effort are noted. (author)

  7. Wet oxidation of a spacecraft model waste

    Science.gov (United States)

    Johnson, C. C.; Wydeven, T.

    1985-01-01

    Wet oxidation was used to oxidize a spacecraft model waste under different oxidation conditions. The variables studied were pressure, temperature, duration of oxidation, and the use of one homogeneous and three heterogeneous catalysts. Emphasis is placed on the final oxidation state of carbon and nitrogen since these are the two major components of the spacecraft model waste and two important plant nutrients.

  8. Advanced methods for the treatment of organic aqueous wastes: wet air oxidation and wet peroxide oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Debellefontaine, Hubert; Chakchouk, Mehrez; Foussard, Jean Noel [Institut National des Sciences Appliquees (INSA), 31 - Toulouse (France). Dept. de Genie des Procedes Industriels; Tissot, Daniel; Striolo, Phillipe [IDE Environnement S.A., Toulouse (France)

    1993-12-31

    There is a growing concern about the problems of wastes elimination. Various oxidation techniques are suited for elimination of organic aqueous wastes, however, because of the environmental drawbacks of incineration, liquid phase oxidation should be preferred. `Wet Air Oxidation` and `Wet Peroxide Oxidation`are alternative processes which are discussed in this paper. 17 refs., 13 figs., 4 tabs.

  9. Wet Chemistry of Spinel Iron oxide Particles

    OpenAIRE

    Jolivet, J.; Chanéac, C.; Prené, P.; Vayssières, L.; Tronc, E.

    1997-01-01

    Various properties of spinel iron oxide nanograins are reviewed, illustrating the broad possibilities of wet chemistry for tailoring materials for a wide range of utilizations, from catalysis and sensors to cast magnetic materials.

  10. Fuel ethanol production from wet oxidised corn stover by S. cerevisiae

    DEFF Research Database (Denmark)

    Qiang, zhang; Thomsen, Anne Belinda

    2012-01-01

    In order to find out appropriate process for ethanol production from corn stover, wet oxidation (195°C, 15 minutes) and simultaneous saccharification and fermentation (SSF) was carried out to produce ethanol. The results showed that the cellulose recovery of 92.9% and the hemicellulose recovery of...

  11. Wet oxidation processes for water pollution remediation

    OpenAIRE

    García Molina, Verónica

    2006-01-01

    [eng] The main objective of this work was to test the efficiency of wet oxidation processes when treating several types of aqueous wastes. On one side its performance for the abatement of chloro-organic aromatic toxic pollutants, such as 4-chlorophenol and 2,4-dichlorophenol has been studied. On the other hand, wastewater from pulp and paper mills, which has been reported to be an indirect source of entry of chlorophenols in the aquatic environment, has been investigated. More in detail, it h...

  12. Specific features of aluminum nanoparticle water and wet air oxidation

    International Nuclear Information System (INIS)

    The oxidation processes of the electrically exploded aluminum nanopowders in water and in wet air are examined in the paper. The morphology of the intermediate reaction products of aluminum oxidation has been studied using the transmission electron microscopy. It was shown that the aluminum nanopowder water oxidation causes the formation of the hollow spheres with mesoporous boehmite nanosheets coating. The wedge-like bayerite particles are formed during aluminum nanopowder wet air oxidation

  13. Copper oxide nanoparticles inhibit the metabolic activity of Saccharomyces cerevisiae.

    Science.gov (United States)

    Mashock, Michael J; Kappell, Anthony D; Hallaj, Nadia; Hristova, Krassimira R

    2016-01-01

    Copper oxide nanoparticles (CuO NPs) are used increasingly in industrial applications and consumer products and thus may pose risk to human and environmental health. The interaction of CuO NPs with complex media and the impact on cell metabolism when exposed to sublethal concentrations are largely unknown. In the present study, the short-term effects of 2 different sized manufactured CuO NPs on metabolic activity of Saccharomyces cerevisiae were studied. The role of released Cu(2+) during dissolution of NPs in the growth media and the CuO nanostructure were considered. Characterization showed that the 28 nm and 64 nm CuO NPs used in the present study have different primary diameter, similar hydrodynamic diameter, and significantly different concentrations of dissolved Cu(2+) ions in the growth media released from the same initial NP mass. Exposures to CuO NPs or the released Cu(2+) fraction, at doses that do not have impact on cell viability, showed significant inhibition on S. cerevisiae cellular metabolic activity. A greater CuO NP effect on the metabolic activity of S. cerevisiae growth under respiring conditions was observed. Under the tested conditions the observed metabolic inhibition from the NPs was not explained fully by the released Cu ions from the dissolving NPs. PMID:26178758

  14. Exposure to benzene metabolites causes oxidative damage in Saccharomyces cerevisiae.

    Science.gov (United States)

    Raj, Abhishek; Nachiappan, Vasanthi

    2016-06-01

    Hydroquinone (HQ) and benzoquinone (BQ) are known benzene metabolites that form reactive intermediates such as reactive oxygen species (ROS). This study attempts to understand the effect of benzene metabolites (HQ and BQ) on the antioxidant status, cell morphology, ROS levels and lipid alterations in the yeast Saccharomyces cerevisiae. There was a reduction in the growth pattern of wild-type cells exposed to HQ/BQ. Exposure of yeast cells to benzene metabolites increased the activity of the anti-oxidant enzymes catalase, superoxide dismutase and glutathione peroxidase but lead to a decrease in ascorbic acid and reduced glutathione. Increased triglyceride level and decreased phospholipid levels were observed with exposure to HQ and BQ. These results suggest that the enzymatic antioxidants were increased and are involved in the protection against macromolecular damage during oxidative stress; presumptively, these enzymes are essential for scavenging the pro-oxidant effects of benzene metabolites. PMID:27016252

  15. Wet Air Oxidation and Catalytic Wet Air Oxidation for Refinery Spent Caustics Degradation

    International Nuclear Information System (INIS)

    The work focuses on evaluating wet air oxidation and catalytic wet air oxidation technique to degrade refinery spent caustics (original COD is 250,781 mg/L) in a milder operation conditions (150-200 degree C, 0.2-2.5MPa). The results show that: in non-catalyst WAO, the highest COD degradation conversion could reach about 75% when 200 degree C, 2MPa oxygen and 300rpm were used. At every temperature, the reaction procedures follow pseudo-first order equations and the activation energy is 45.5 kJ/mol. The reactivity of three main contaminants in wastewater is on the order of sulphide > petroleum > volatile phenol. The COD degradation conversion could improve to about 95% when composite catalyst MnOx-CeO/sub x//sub x/ gamma-Al/sub 2/O/sub 3/ (W/sub Mn//W gamma-/sub Al/sub 2/O/sub 3/ =0.5/ and WCe/W MnOx Al/sub 2/O/sub 3/=0.4) was used. The pseudo-first order equations also could be applied for catalyst system and its activation energy decreases to 27.2 kJ/mol. The catalyst could improve the degradation efficiency of petroleum and volatile phenol. Their conversions could increase to 85% and 74% respectively after catalyst used. (author)

  16. Wet-air oxidation cleans up black wastewater

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    Sterling Organics produces the analgesic paracetamol (acetaminophen) at its Dudley, England, plant. The wastewater from the batch process contains intermediates such as para-aminophenol (PAP) and byproducts such as thiosulfates, sulfites and sulfides. To stay ahead of increasingly strict environmental legislation, Sterling Organics installed a wet-air oxidation system at the Dudley facility in August 1992. The system is made by Zimpro Environmental Inc. (Rothschild, Wis.). Zimpro's wet-air oxidation system finds a way around the limitations of purely chemical or physical processes. In the process, compressed air at elevated temperature and pressure oxidizes the process intermediates and byproducts and removes the color from the wastewater.

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

    OpenAIRE

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

    2013-01-01

    Abstract 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...

  18. The Study of LeachateTreatment by Using Three Advanced Oxidation Process Based Wet air Oxidation

    OpenAIRE

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

    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 unde...

  19. Graphene-based materials in catalytic wet peroxide oxidation

    OpenAIRE

    Gomes, Helder; Ribeiro, Rui; Pastrana-Martínez, Luisa; Figueiredo, José; Faria, Joaquim; Silva, Adrián

    2014-01-01

    In catalytic wet peroxide oxidation (CWPO),an advanced oxidation process, hydrogen peroxide (H2O2) is decomposed catalytically giving rise to hydroxyl radicals (HO•).These radicals, exhibiting high oxidizing potential, serve as effective and non selective species for the degradation of several organic pollutants in liquid phase. Since the report of Lücking et al. [1], carbon materials have been explored as catalysts for CWPO[2]. Recent reports address process intensification issues, br...

  20. Catalytic wet Air Oxidation of o-Chlorophenol in Wastewater

    Institute of Scientific and Technical Information of China (English)

    徐新华; 汪大翬

    2003-01-01

    Catalytic wet air oxidation (CWAO) was investigated in laboratory-scale experiments for the treatment of o-chlorophenol in wastewater. Experimental results showed that wet air oxidation (WAO) process in the absence of catalyst was also effective for o-chlorophenol in wastewater treatment. Up to 80% of the initial CODCr was removed by wet air oxidation at 270℃ with twice amount of the required stoichiometric oxygen supply. At temperature of 150℃, the removal rate of CODCr was only 30%. Fe2(SO4)3, CuSO4, Cu(NO3)2 and MnSO4 exhibited high catalytic activity. Higher removal rate of CODCr was obtained by CWAO. More than 96% of the initial CODCr was removed at 270℃ and 84.6%-93.6% of the initial CODCr was removed at 150℃. Mixed catalysts had better catalytic activity for the degradation of o-chlorophenol in wastewater.

  1. Wet Oxidation of PVA-Containing Desizing Wastewater

    Institute of Scientific and Technical Information of China (English)

    雷乐成; 汪大翬

    2000-01-01

    Polyvinyl alcohol (PVA)-containing desizing wastewater was treated by various wet oxidation methods.Parameters such as reaction temperature, initial solution pH, and the dosage of H2O2 were investigated in terms of chemical oxygen demand (CODcr) and total organic carbon (TOC) removal rate. Up to 90% of the initial CODcr was removed by wet air oxidation(WAO) at 270℃ with stoichiometric oxygen supply, while at temperature of 200℃, the CODcr removal rate was found to be 80%. Similar results were obtained by Promoted WAO (PWAO) and wet peroxide oxidation(WPO) at a lower temperature of 150℃. Reaction temperature was found to have a significant effect on the oxidation performance for all the methods. Initial solution pH was observed to play a significant role in PWAO and WPO where H2O2 was employed. Comparison of WAO, CWAO(catalytic wet air oxidation), PWAO and WPO shows that the rate of CODcr removal increases in the order: WAO, CWAO, PWAO and WPO.

  2. Oxidation and wet wear of silicon carbide

    OpenAIRE

    Presser, Volker

    2009-01-01

    Siliziumkarbid (SiC) ist sowohl die wohl bedeutendste Nichtoxidkeramik aber auch als Halbleiter ein vielversprechendes Material. Gaskorrosion in Gegenwart von Sauerstoff führt dabei als einzige feste Phase zu Bildung von SiO2 (passive Oxidation). Hierbei spielen jedoch viele Einflussfaktoren eine wichtige Rolle, wie zum Beispiel Porosität, Sinteradditive, Verunreinigungen, die kristallographische Orientierung, vorhergehende Oberflächenbehandlung und die chemische Zusammensetzung der oxidie...

  3. The applicability of the catalytic wet-oxidation to CELSS

    Science.gov (United States)

    Takahashi, Y.; Nitta, K.; Ohya, H.; Oguchi, M.

    1987-01-01

    The wet oxidation catalysis of Au, Pd, Pt, Rh or Ru on a ceramic honeycomb carrier was traced in detail by 16 to 20 repetitive batch tests each. As a result, Pt or Pd on a honeycomb carrier was shown to catalyze complete nitrogen gasification as N2. Though the catalysts which realize both complete nitrogen gasification and complete oxidation could not be found, the Ru+Rh catalyst was found to be most promising. Ru honeycomb catalyzed both nitrification and nitrogen gasification.

  4. Optimization of wet oxidation pretreatment of wheat straw

    DEFF Research Database (Denmark)

    Schmidt, A.S.; Thomsen, A.B.

    1998-01-01

    The wet oxidation process (water; oxygen and elevated temperature) was investigated under alkaline conditions for fractionation of hemicellulose, cellulose, and lignin from wheat straw. At higher temperature and longer reaction time, a purified cellulose fraction (69% w/w) was produced with high...

  5. The Response to Heat Shock and Oxidative Stress in Saccharomyces cerevisiae

    OpenAIRE

    Morano, Kevin A.; Grant, Chris M.; Moye-Rowley, W. Scott

    2012-01-01

    A common need for microbial cells is the ability to respond to potentially toxic environmental insults. Here we review the progress in understanding the response of the yeast Saccharomyces cerevisiae to two important environmental stresses: heat shock and oxidative stress. Both of these stresses are fundamental challenges that microbes of all types will experience. The study of these environmental stress responses in S. cerevisiae has illuminated many of the features now viewed as central to ...

  6. Wet oxidation as a waste treatment in closed systems

    Science.gov (United States)

    Onisko, B. L.; Wydeven, T.

    1981-01-01

    The chemistry of the wet oxidation process has been investigated in relation to production of plant nutrients from plant and human waste materials as required for a closed life-support system. Hydroponically grown lettuce plants were used as a model plant waste and oxygen gas was used as oxidant. Organic nitrogen content was decreased 88-100% depending on feed material. Production of ammonia and nitrogen gas account for all of the observed decrease in organic nitrogen content. No nitrous oxide (N2O) was detected. The implications of these results for closed life-support systems are discussed.

  7. Wet Oxidation as a Waste Treatment Method in Closed Systems

    Science.gov (United States)

    Onisko, B. L.; Wydeven, T.

    1982-01-01

    The chemistry of the wet oxidation process was investigated in relation to production of plant nutrients from plant and human waste materials as required for a closed life support system. Hydroponically grown lettuce plants were used as a model plant waste, and oxygen gas was used as an oxidant. Organic nitrogen content was decreased 88-100%, depending on feed material. Production of ammonia and nitrogen gas accounted for all of the observed decrease in organic nitrogen content. No nitrous oxide (N2O) was detected. The implications of these results for closed life support systems are discussed.

  8. Process of forming catalytic surfaces for wet oxidation reactions

    Science.gov (United States)

    Jagow, R. B. (Inventor)

    1977-01-01

    A wet oxidation process was developed for oxidizing waste materials, comprising dissolved ruthenium salt in a reactant feed stream containing the waste materials. The feed stream is introduced into a reactor, and the reactor contents are then raised to an elevated temperature to effect deposition of a catalytic surface of ruthenium black on the interior walls of the reactor. The feed stream is then maintained in the reactor for a period of time sufficient to effect at least partial oxidation of the waste materials.

  9. Wet oxidation of real coke wastewater containing high thiocyanate concentration.

    Science.gov (United States)

    Oulego, Paula; Collado, Sergio; Garrido, Laura; Laca, Adriana; Rendueles, Manuel; Díaz, Mario

    2014-01-01

    Coke wastewaters, in particular those with high thiocyanate concentrations, represent an important environmental problem because of their very low biodegradability. In this work, the treatment by wet oxidation of real coke wastewaters containing concentrations of thiocyanate above 17 mM has been studied in a 1-L semi-batch reactor at temperatures between 453 and 493 K, with total oxygen pressures in the range of 2.0-8.0 MPa. A positive effect of the matrix of real coke wastewater was observed, resulting in faster thiocyanate degradation than was obtained with synthetic wastewaters. Besides, the effect of oxygen concentration and temperature on thiocyanate wet oxidation was more noticeable in real effluents than in synthetic wastewaters containing only thiocyanate. It was also observed that the degree of mineralization of the matrix organic compounds was higher when the initial thiocyanate concentration increased. Taking into account the experimental data, kinetic models were obtained, and a mechanism implying free radicals was proposed for thiocyanate oxidation in the matrix considered. In all cases, sulphate, carbonates and ammonium were identified as the main reaction products of thiocyanate wet oxidation. PMID:24269931

  10. Wet Electrolytic Oxidation of Organics and Application for Sludge Treatment

    Science.gov (United States)

    Serikawa, Roberto M.

    Wet electrolytic oxidation (WEO) is electrochemical oxidation conducted at subcritical water temperature and pressure. Under these conditions, the electrolytic reaction of water is very different from the reaction usually seen in water electrolysis. Electrolysis of an aqueous NaCl solution at 250°C proceeds without the evolution of any oxygen, chlorine or even hydrogen. Rapid oxidation of organics to CO2 occurs in WEO with the production of hydrogen. Further addition of an oxidizer enhances the electrochemical oxidation of organics with the suppression of hydrogen evolution. AOX compounds found in usual electrooxidation are not formed in WEO treatment. When WEO is applied to sludge treatment, colors are drastically reduced and there is an increase in the yield of organic acids. The biodegradability increases by up to 50% and the treated water shows higher methane yields during anaerobic fermentation.

  11. Microwave assisted wet oxidation of p-nitrophenol

    Institute of Scientific and Technical Information of China (English)

    BO; Longli; CHEN; Shuo; QUAN; Xie; LIU; Xitao; ZHAO; Huimin

    2005-01-01

    Aqueous solution of p-nitrophenol (PNP) was treated continuously by microwave assisted wet oxidation while flowing through a granular activated carbon (GAC) fixed bed. PNP was pre-adsorbed onto GAC prior to being put into the reactor so as to prevent PNP adsorption on GAC during microwave irradiation. PNP solutions with different initial concentration (218.6 mg/L and 1200 mg/L) were treated under conditions of microwave power 500 W, liquid flow 6.4 mL/min and air flow 40 mL/min or 60 mL/min. The results indicated that the removal of PNP was higher than 90% and more than 65% PNP was mineralized. Phenol, nitrobenzene, hydroquinone and benzoquinone occurred as course products during the operation process, which were degraded further. The biodegradability of the outflow was improved greatly by microwave assisted wet oxidation.

  12. Evaluation of wet oxidation pretreatment for enzymatic hydrolysis of softwood

    DEFF Research Database (Denmark)

    Palonen, H.; Thomsen, A.B.; Tenkanen, M.;

    2004-01-01

    The wet oxidation pretreatment (water, oxygen, elevated temperature, and pressure) of softwood (Picea abies) was investigated for enhancing enzymatic hydrolysis. The pretreatment was preliminarily optimized. Six different combinations of reaction time, temperature, and pH were applied, and the...... compositions of solid and liquid fractions were analyzed. The solid fraction after wet oxidation contained 58-64% cellulose, 2-16% hemicellulose, and 24-30% lignin. The pretreatment series gave information about the roles of lignin and hemicellulose in the enzymatic hydrolysis. The temperature of the...... pretreatment, the residual hemicellulose content of the substrate, and the type of the commercial cellulase preparation used were the most important factors affecting the enzymatic hydrolysis. The highest sugar yield in a 72-h hydrolysis, 79% of theoretical, was obtained using a pretreatment of 200degreesC for...

  13. Combined wet oxidation and alkaline hydrolysis of polyvinylchloride

    DEFF Research Database (Denmark)

    Sørensen, E.; Bjerre, A.B.

    1992-01-01

    In view of the widespread aversion to burning polyvinylchloride (PVC) together with municipal waste, we have attempted an alternative approach to its decomposition. This paper describes a combined wet oxidation/alkaline hydrolysis yielding water soluble, biodegradable products. Experiments were...... carried out at temperatures from 180-260 degree C and reaction times of 8-24 min. The chloride liberated provides information on the rate constants. Considering the measured Cl- and Chemical Oxygen Demand (COD) values, we find hydrolysis and oxidation processes to be interdependent. The main products are...

  14. Development studies of a novel wet oxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, T.W.; Dhooge, P.M. [Delphi Research, Inc., Albuquerque, NM (United States)

    1995-10-01

    Many DOE waste streams and remediates contain complex and variable mixtures of organic compounds, toxic metals, and radionuclides. These materials are often dispersed in organic or inorganic matrices, such as personal protective equipment, various sludges, soils, and water. Incineration and similar combustive processes do not appear to be viable options for treatment of these waste streams due to various considerations. The objective of this project is to develop a novel catalytic wet oxidation process for the treatment of multi-component wastes. The DETOX process uses a unique combination of metal catalysts to increase the rate of oxidation of organic materials.

  15. Wet-oxidation waste management system for CELSS

    Science.gov (United States)

    Takahashi, Y.; Ohya, H.

    1986-01-01

    A wet oxidation system will be useful in the Closed Ecological Life Support System (CELSS) as a facility to treat organic wastes and to redistribute inorganic compounds and elements. However at rather higher temperatures needed in this reaction, for instance, at 260 deg C, only 80% of organic in a raw material can be oxidized, and 20% of it will remain in the liquid mainly as acetic acid, which is virtually noncombustible. Furthermore, nitrogen is transformed to ammonium ions which normally cannot be absorbed by plants. To resolve these problems, it becomes necessary to use catalysts. Noble metals such as Ru, Rh and so on have proved to be partially effective as these catalysts. That is, oxidation does not occur completely, and the unexpected denitrification, instead of the expected nitrification, occurs. So, it is essential to develop the catalysts which are able to realize the complete oxidation and the nitrification.

  16. Wet oxidation pretreatment of rape straw for ethanol production

    International Nuclear Information System (INIS)

    Rape straw can be used for production of second generation bioethanol. In this paper we optimized the pretreatment of rape straw for this purpose using Wet oxidation (WO). The effect of reaction temperature, reaction time, and oxygen gas pressure was investigated for maximum ethanol yield via Simultaneous Saccharification and Fermentation (SSF). To reduce the water use and increase the energy efficiency in WO pretreatment features like recycling liquid (filtrate), presoaking of rape straw in water or recycled filtrate before WO, skip washing pretreated solids (filter cake) after WO, or use of whole slurry (Filter cake + filtrate) in SSF were also tested. Except ethanol yields, pretreatment methods were evaluated based on achieved glucose yields, amount of water used, recovery of cellulose, hemicellulose, and lignin. The highest ethanol yield obtained was 67% after fermenting the whole slurry produced by WO at 205 °C for 3 min with 12 bar of oxygen gas pressure and featured with presoaking in water. At these conditions after pre-treatment, cellulose and hemicellulose was recovered quantitatively (100%) together with 86% of the lignin. WO treatments of 2–3 min at 205–210 °C with 12 bar of oxygen gas produced higher ethanol yields and cellulose, hemicelluloses, and lignin recoveries, than 15 min WO treatment at 195 °C. Also, recycling filtrate and use of higher oxygen gas pressure reduced recovery of materials. The use of filtrate could be inhibitory for the yeast, but also reduced lactic acid formation in SSF. -- Highlights: ► Wet Oxidation pretreatment on rape straw for sugar and ethanol production. ► Variables were reaction time, temperature, and oxygen gas pressure. ► Also, other configurations for increase of water and energy efficiency. ► Short Wet oxidation pretreatment (2–3 min) produced highest ethanol yield. ► After these pretreatment conditions recovery of lignin in solids was 86%.

  17. Development studies for a novel wet oxidation process

    International Nuclear Information System (INIS)

    A catalytic wet oxidation process (DETOX), which uses an acidic iron solution to oxidize organic compounds to carbon dioxide, water, and other simple products, was investigated as a potential method for the treatment of multicomponent hazardous and mixed wastes. The organic compounds picric acid, poly(vinyl chloride), tetrachlorothiophene, pentachloropyridine, Aroclor 1260 (a polychlorinated biphenyl), and hexachlorobenzene were oxidized in 125 ml reaction vessels. The metals arsenic, barium, beryllium, cadmium, cerium (as a surrogate for plutonium), chromium, lead, mercury, neodymium (as a surrogate for uranium), nickel, and vanadium were tested in the DETOX solution. Barium, beryllium, cerium, chromium, mercury, neodymium, nickel, and vanadium were all found to be very soluble (>100 g/l) in the DETOX chloride-based solution. Arsenic, barium, cadmium, and lead solubilities were lower. Lead could be selectively precipitated from the DETOX solution. Chromium(VI) was reduced to relatively non-toxic chromium(III) by the solution. Six soils were contaminated with arsenic, barium, beryllium, chromium, lead, and neodymium oxides at approximately 0.1% by weight, and benzene, trichloroethene, mineral oil, and Aroclor 1260 at approximately 5% by weight total, and 5.g amounts treated with the DETOX solution in unstirred 125. ml reaction bombs. It is felt that soil treatment in a properly designed system is entirely possible despite incomplete oxidation of the less volatile organic materials in these unstirred tests

  18. Development studies for a novel wet oxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Dhooge, P.M.; Hakim, L.B.

    1994-01-01

    A catalytic wet oxidation process (DETOX), which uses an acidic iron solution to oxidize organic compounds to carbon dioxide, water, and other simple products, was investigated as a potential method for the treatment of multicomponent hazardous and mixed wastes. The organic compounds picric acid, poly(vinyl chloride), tetrachlorothiophene, pentachloropyridine, Aroclor 1260 (a polychlorinated biphenyl), and hexachlorobenzene were oxidized in 125 ml reaction vessels. The metals arsenic, barium, beryllium, cadmium, cerium (as a surrogate for plutonium), chromium, lead, mercury, neodymium (as a surrogate for uranium), nickel, and vanadium were tested in the DETOX solution. Barium, beryllium, cerium, chromium, mercury, neodymium, nickel, and vanadium were all found to be very soluble (>100 g/l) in the DETOX chloride-based solution. Arsenic, barium, cadmium, and lead solubilities were lower. Lead could be selectively precipitated from the DETOX solution. Chromium(VI) was reduced to relatively non-toxic chromium(III) by the solution. Six soils were contaminated with arsenic, barium, beryllium, chromium, lead, and neodymium oxides at approximately 0.1% by weight, and benzene, trichloroethene, mineral oil, and Aroclor 1260 at approximately 5% by weight total, and 5.g amounts treated with the DETOX solution in unstirred 125. ml reaction bombs. It is felt that soil treatment in a properly designed system is entirely possible despite incomplete oxidation of the less volatile organic materials in these unstirred tests.

  19. Pretreatment of apramycin wastewater by catalytic wet air oxidation

    Institute of Scientific and Technical Information of China (English)

    YANG Shao-xia; FENG Yu-jie; WAN Jia-feng; LIN Qing-ying; ZHU Wan-peng; JIANG Zhan-peng

    2005-01-01

    The pretreatment technology of wet air oxidation(WAO) and coagulation and acidic hydrolysis for apramycin wastewater was investigated in this paper. The COD, apramycin, NH4+ concentration, and the ratio of BOD5/COD were analyzed, and the color and odor of the effluent were observed. WAO of apramycin wastewater, without catalyst and with RuO2/Al2 O3 and RuO2-CeO2/Al2 O3 catalysts, was carried out at degradation temperature of 200℃ and the total pressure of 4 MPa in a 1 L batch reactor. The result showed that the apramycin removals were respectively 50.2% and 55.0%, COD removals were 40.0% and 46.0%, and the ratio of BOD5/COD was increased to 0.49 and 0.54 with RuO2/Al2 O3 and RuO2-CeO2/Al2 O3 catalysts in catylytic wet air oxidation(CWAO) after the reaction of 150 min. With the pretreatment of coagulation and acidic hydrolysis, COD and apramycin removals were slight decreased, and the ratio of BOD5/COD was increased to 0.45, and the effluents was not suitable to biological treatment. The color and odor of the wastewater were the apramycin wastewater. The addition of CeO2 could promote the activity and stability of RuO2/Al2 O3 in WAO of apramycin wastewater.

  20. Leachate Treatment UsingWet Air Oxidation Processes

    Directory of Open Access Journals (Sweden)

    A Ebrahimi

    2011-04-01

    Full Text Available "nBackground and Objectives: Wet air oxidation (WAO is One of the advanced oxidation process which reduce organic matter concentration from industrial wastewater, toxic and non biodegradable substances and, solid waste leachate,etc. In this study the efficiency of wet air oxidation method in leachate treatment generating from Esfahan Composting factory was Evaluated."nMaterial and Methods: The experiment was carried out by adding 1.5 Lit of pretreated leachate sample the steel reactor with the volume of 3L. The reactor then underwent10 bar pressure at different temperature (100, 200 and 300 °C and various retention time (30, 60 and 90 min. Leachate sample in 18 stages from composting factory in Isfahan in the volume of 20 Lit was taken and the WAO method, was used for pre-treatments. Removal efficiency of COD, BOD, NH4-N, NO3 and TSS were examined."nResults: The results showed that the removal efficiency was more than 35% for COD, 38% for BOD, and 85% for TSS within one hour of reaction. The Maximum removal efficiency obtained in this study were 53.3% for NH4-N and 73.9 % forNO3-N."nConclusion: the results indicate that the reaction temperatures are the most important factors affecting degradation of organic matter. COD and BOD5 removal efficiency by WAO process increased as the time of reaction went up. In addition, BOD5/COD ratios of the effluents, which are generally regarded as an important index of biodegradability of leachate sample, were determined and improved grately as it reached to 84%. TheWAO process presented in this paper is considered an efficient process for pretreatment of leachate, as the COD, BOD5 and NO3 reduction observed in leachate samples.

  1. Comparison between wet oxidation and steam explosion as pretreatment methods for enzymatic hydrolysis of sugarcane bagasse

    DEFF Research Database (Denmark)

    Medina, Carlos Martín; Marcet, M.; Thomsen, Anne Belinda

    2008-01-01

    Alkaline wet oxidation and steam explosion pretreatments of sugarcane bagasse were compared with regard to biomass fractionation, formation of by-products, and enzymatic convertibility of the pretreated material. Wet oxidation led to the solubilisation of 82% of xylan and 50% of lignin, and to a...... significantly in steam explosion. This investigation demonstrates the potential of wet oxidation as a promising pretreatment method for enzyme-based bagasse-to-ethanol processes....

  2. Catalytic wet air oxidation of chlorophenols over supported ruthenium catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Li Ning [Institut de recherches sur la catalyse et l' environnement de Lyon (IRCELYON), UMR 5256, CNRS/Universite Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France); Descorme, Claude [Institut de recherches sur la catalyse et l' environnement de Lyon (IRCELYON), UMR 5256, CNRS/Universite Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France)]. E-mail: claude.descorme@catalyse.cnrs.fr; Besson, Michele [Institut de recherches sur la catalyse et l' environnement de Lyon (IRCELYON), UMR 5256, CNRS/Universite Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France)

    2007-07-31

    A series of noble metal (Pt, Pd, Ru) loaded zirconia catalysts were evaluated in the catalytic wet air oxidation (CWAO) of mono-chlorophenols (2-CP, 3-CP, 4-CP) under relatively mild reaction conditions. Among the investigated noble metals, Ru appeared to be the best to promote the CWAO of CPs as far as incipient-wetness impregnation was used to prepare all the catalysts. The position of the chlorine substitution on the aromatic ring was also shown to have a significant effect on the CP reactivity in the CWAO over 3 wt.% Ru/ZrO{sub 2}. 2-CP was relatively easier to degradate compared to 3-CP and 4-CP. One reason could be the higher adsorption of 2-CP on the catalyst surface. Further investigations suggested that 3 wt.% Ru/ZrO{sub 2} is a very efficient catalyst in the CWAO of 2-CP as far as high 2-CP conversion and TOC abatement could still be reached at even lower temperature (393 K) and lower total pressure (3 MPa). Additionally, the conversion of 2-CP was demonstrated to increase with the initial pH of the 2-CP solution. The dechlorination reaction is promoted at higher pH. In all cases, the adsorption of the reactants and the reaction intermediates was shown to play a major role. All parameters that would control the molecule speciation in solution or the catalyst surface properties would have a key effect.

  3. Transformation and removal of wood extractives from pulp mill sludge using wet oxidation and thermal hydrolysis.

    Science.gov (United States)

    Baroutian, Saeid; Robinson, Murray; Smit, Anne-Marie; Wijeyekoon, Suren; Gapes, Daniel

    2013-10-01

    In order to remove wood extractive compounds from pulp mill sludge and thereby enhancing anaerobic digestibility, samples were subjected to either oxidative hydrothermal treatment (wet oxidation) or non-oxidative hydrothermal treatment (thermal hydrolysis). Treatments were carried out at 220 °C with initial pressure of 20 bar. More than 90% destruction of extractive compounds was observed after 20 min of wet oxidation. Wet oxidation eliminated 95.7% of phenolics, 98.6% fatty acids, 99.8% resin acids and 100% of phytosterols in 120 min. Acetic acid concentration increased by approximately 2 g/l after 120 min of wet oxidation. This has potential for rendering sludge more amenable to anaerobic digestion. In contrast thermal hydrolysis was found to be ineffective in degrading extractive compounds. Wet oxidation is considered to be an effective process for removal of recalcitrant and inhibitive compounds through hydrothermal pre-treatment of pulp mill sludge. PMID:23948266

  4. Wet oxidation pretreatment of rape straw for ethanol production

    DEFF Research Database (Denmark)

    Arvaniti, Efthalia; Bjerre, Anne Belinda; Schmidt, Jens Ejbye

    2012-01-01

    Rape straw can be used for production of second generation bioethanol. In this paper we optimized the pretreatment of rape straw for this purpose using Wet oxidation (WO). The effect of reaction temperature, reaction time, and oxygen gas pressure was investigated for maximum ethanol yield via...... slurry (Filter cake + filtrate) in SSF were also tested. Except ethanol yields, pretreatment methods were evaluated based on achieved glucose yields, amount of water used, recovery of cellulose, hemicellulose, and lignin.The highest ethanol yield obtained was 67% after fermenting the whole slurry...... gas produced higher ethanol yields and cellulose, hemicelluloses, and lignin recoveries, than 15 min WO treatment at 195 °C. Also, recycling filtrate and use of higher oxygen gas pressure reduced recovery of materials. The use of filtrate could be inhibitory for the yeast, but also reduced lactic acid...

  5. Homogeneous catalytic wet air oxidation for the treatment oftextile wastewaters

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An extensive series of experiments was carried out in order to identify suitable catalysts to boost the reaction rate of wet air oxidation of real textile wastewaters at relatively mild temperature and pressure. Experimental results indicated that all catalysts tested in this investigation had shown an impressive increase in the initial COD and TOC removal rate as well as the COD and TOC removal levels in two hours reaction. Among all the catalysts tested, copper salts were more effective than the rest. Anions of the salt soluffonsalso played a role in the catalytic process with nitrate ions having better effect than sulfate ions. Hence copper nitrates were more effective than copper sulfates. It was also found that a mixture of salts with different metals performed better than either of the component single salt alone.

  6. The use of catalyst to enhance the wet oxidation process.

    Science.gov (United States)

    Maugans, C; Kumfer, B

    2007-01-01

    Wet oxidation tests were performed on two pure compound streams: acetic acid and ammonia; and on two wastewater streams: acrylic acid wastewater and sulphide laden spent caustic. Test results showed that Mn/Ce and Pt/TiO2 were effective catalysts that greatly enhanced acetic acid, ammonia and acrylic acid wastewater destruction. However, the Mn/Ce catalyst performance appears to be inhibited by concentrated salts dissolved in solution. This could limit the applicability of this catalyst for the treatment of brackish wastewaters. Zr, Ce and Ce nanoparticles were also shown to exhibit some catalytic activity, however not to the extent of the Mn/Ce and the Pt/TiO2. PMID:17674847

  7. Oxidative stress is involved in heat-induced cell death in Saccharomyces cerevisiae.

    OpenAIRE

    Davidson, J. F.; Whyte, B.; Bissinger, P H; Schiestl, R H

    1996-01-01

    The cause for death after lethal heat shock is not well understood. A shift from low to intermediate temperature causes the induction of heat-shock proteins in most organisms. However, except for HSP104, a convincing involvement of heat-shock proteins in the development of stress resistance has not been established in Saccharomyces cerevisiae. This paper shows that oxidative stress and antioxidant enzymes play a major role in heat-induced cell death in yeast. Mutants deleted for the antioxida...

  8. Preliminary comparison of three processes of AlN oxidation: dry, wet and mixed ones

    Directory of Open Access Journals (Sweden)

    Korbutowicz R.

    2016-03-01

    Full Text Available Three methods of AlN layers oxidation: dry, wet and mixed (wet with oxygen were compared. Some physical parameters of oxidized thin films of aluminum nitride (AlN layers grown on silicon Si(1 1 1 were investigated by means Energy-Dispersive X-ray Spectroscopy (EDS and Spectroscopic Ellipsometry (SE. Three series of the thermal oxidations processes were carried out at 1012 °C in pure nitrogen as carrying gas and various gas ambients: (a dry oxidation with oxygen, (b wet oxidation with water steam and (c mixed atmosphere with various process times. All the research methods have shown that along with the rising of the oxidation time, AlN layer across the aluminum oxide nitride transforms to aluminum oxide. The mixed oxidation was a faster method than the dry or wet ones.

  9. Degradation of paracetamol by catalytic wet air oxidation and sequential adsorption – Catalytic wet air oxidation on activated carbons

    International Nuclear Information System (INIS)

    Highlights: ► Three activated carbons (AC) compared as adsorbents and oxidation catalysts. ► Similar evolution for catalytic and adsorptive properties of AC over reuses. ► Acidic and mesoporous AC to be preferred, despite lower initial efficiency. ► Oxidative degradation of paracetamol improves biodegradability. ► Convenient hybrid adsorption–regenerative oxidation process for continuous treatment. - Abstract: The concern about the fate of pharmaceutical products has raised owing to the increasing contamination of rivers, lakes and groundwater. The aim of this paper is to evaluate two different processes for paracetamol removal. The catalytic wet air oxidation (CWAO) of paracetamol on activated carbon was investigated both as a water treatment technique using an autoclave reactor and as a regenerative treatment of the carbon after adsorption in a sequential fixed bed process. Three activated carbons (ACs) from different source materials were used as catalysts: two microporous basic ACs (S23 and C1) and a meso- and micro-porous acidic one (L27). During the first CWAO experiment the adsorption capacity and catalytic performance of fresh S23 and C1 were higher than those of fresh L27 despite its higher surface area. This situation changed after AC reuse, as finally L27 gave the best results after five CWAO cycles. Respirometry tests with activated sludge revealed that in the studied conditions the use of CWAO enhanced the aerobic biodegradability of the effluent. In the ADOX process L27 also showed better oxidation performances and regeneration efficiency. This different ageing was examined through AC physico-chemical properties.

  10. Degradation of paracetamol by catalytic wet air oxidation and sequential adsorption - Catalytic wet air oxidation on activated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Quesada-Penate, I. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France); Julcour-Lebigue, C., E-mail: carine.julcour@ensiacet.fr [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France); Jauregui-Haza, U.J. [Instituto Superior de Tecnologias y Ciencias Aplicadas, Ave. Salvador Allende y Luaces, Habana (Cuba); Wilhelm, A.M.; Delmas, H. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, 4, Allee Emile Monso, F-31432 Toulouse (France); CNRS, Laboratoire de Genie Chimique, F-31432 Toulouse (France)

    2012-06-30

    Highlights: Black-Right-Pointing-Pointer Three activated carbons (AC) compared as adsorbents and oxidation catalysts. Black-Right-Pointing-Pointer Similar evolution for catalytic and adsorptive properties of AC over reuses. Black-Right-Pointing-Pointer Acidic and mesoporous AC to be preferred, despite lower initial efficiency. Black-Right-Pointing-Pointer Oxidative degradation of paracetamol improves biodegradability. Black-Right-Pointing-Pointer Convenient hybrid adsorption-regenerative oxidation process for continuous treatment. - Abstract: The concern about the fate of pharmaceutical products has raised owing to the increasing contamination of rivers, lakes and groundwater. The aim of this paper is to evaluate two different processes for paracetamol removal. The catalytic wet air oxidation (CWAO) of paracetamol on activated carbon was investigated both as a water treatment technique using an autoclave reactor and as a regenerative treatment of the carbon after adsorption in a sequential fixed bed process. Three activated carbons (ACs) from different source materials were used as catalysts: two microporous basic ACs (S23 and C1) and a meso- and micro-porous acidic one (L27). During the first CWAO experiment the adsorption capacity and catalytic performance of fresh S23 and C1 were higher than those of fresh L27 despite its higher surface area. This situation changed after AC reuse, as finally L27 gave the best results after five CWAO cycles. Respirometry tests with activated sludge revealed that in the studied conditions the use of CWAO enhanced the aerobic biodegradability of the effluent. In the ADOX process L27 also showed better oxidation performances and regeneration efficiency. This different ageing was examined through AC physico-chemical properties.

  11. Preliminary comparison of three processes of AlN oxidation: dry, wet and mixed ones

    OpenAIRE

    Korbutowicz R.; Zakrzewski A.

    2016-01-01

    Three methods of AlN layers oxidation: dry, wet and mixed (wet with oxygen) were compared. Some physical parameters of oxidized thin films of aluminum nitride (AlN) layers grown on silicon Si(1 1 1) were investigated by means Energy-Dispersive X-ray Spectroscopy (EDS) and Spectroscopic Ellipsometry (SE). Three series of the thermal oxidations processes were carried out at 1012 °C in pure nitrogen as carrying gas and various gas ambients: (a) dry oxidation with oxygen, (b) wet oxidation with w...

  12. Treatment of hydraulic fracturing wastewater by wet air oxidation.

    Science.gov (United States)

    Wang, Wei; Yan, Xiuyi; Zhou, Jinghui; Ma, Jiuli

    2016-01-01

    Wastewater produced by hydraulic fracturing for oil and gas production is characterized by high salinity and high chemical oxygen demand (COD). We applied a combination of flocculation and wet air oxidation technology to optimize the reduction of COD in the treatment of hydraulic fracturing wastewater. The experiments used different values of flocculant, coagulant, and oxidizing agent added to the wastewater, as well as different reaction times and treatment temperatures. The use of flocculants for the pretreatment of fracturing wastewater was shown to improve treatment efficiency. The addition of 500 mg/L of polyaluminum chloride (PAC) and 20 mg/L of anionic polyacrylamide (APAM) during pretreatment resulted in a COD removal ratio of 8.2% and reduced the suspended solid concentration of fracturing wastewater to 150 mg/L. For a solution of pretreated fracturing wastewater with 12 mL of added H2O2, the COD was reduced to 104 mg/L when reacted at 300 °C for 75 min, and reduced to 127 mg/L when reacted at the same temperature for 45 min while using a 1 L autoclave. An optimal combination of these parameters produced treated wastewater that met the GB 8978-1996 'Integrated Wastewater Discharge Standard' level I emission standard. PMID:26942530

  13. Catalytic wet air oxidation for the treatment of emulsifying wastewater

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jian-fu; CHEN Ling; LU Yi-cheng; TANG Wen-wei

    2005-01-01

    The wet air oxidation (WAO) and catalytic WAO (CWAO) of the high strength emulsifying wastewater containing nonionic surfactants have been investigated in terms of COD and TOC removal. The WAO and homogeneous CWAO processes were carried out at the temperature from 433 K to 513 K, with initial oxygen pressure 1.2 MPa. It was found that homogeneous catalyst copper(Cu ( NO3 )2 )had an fairly good catalytic activity for the WAO process, and the oxidation was catalyzed when the temperature was higher than 473 K.Moreover, several heterogeneous catalysts were proved to be effective for the WAO process. At the temperature 473 K, after 2 h reaction,WAO process could achieve about 75% COD removal and 66% TOC removal, while catalysts Cu/Al2O3 and Mn-Ce/Al2O3 elevated the COD removal up to 86%-89% and that of TOC up to 82%. However, complete elimination of COD and TOC was proved to be difficult even the best non-noble catalyst was used. Therefore, the effluent from WAO or CWAO process need to be further disposed. The bioassay proved that the effluent from WAO process was amenable to the biochemical method.

  14. Copper on activated carbon for catalytic wet air oxidation

    Directory of Open Access Journals (Sweden)

    Nora Dolores Martínez

    2009-03-01

    Full Text Available Textile industry is an important source of water contamination. Some of the organic contaminants cannot be eliminated by nature in a reasonable period. Heterogeneous catalytic wet air oxidation is one of the most effective methods to purify wastewater with organic contaminants. In this work, catalysts based on copper supported on activated carbon were synthesized. The activated carbons were obtained from industrial wastes (apricot core and grape stalk of San Juan, Argentina. These were impregnated with a copper salt and thermically treated in an inert atmosphere. Analysis of specific surface, pore volume, p zc, acidity, basicity and XRD patterns were made in order to characterize the catalysts. The catalytic activity was tested in the oxidation of methylene blue (MB and polyvinyl alcohol (PVA in aqueous phase with pure oxygen. Reaction tests were carried out in a Parr batch reactor at different temperatures, with a 0.2 MPa partial pressure of oxygen. The amount of unconverted organics was measured by spectrophotometry. Higher temperatures were necessary for the degradation of PVA compared to those for methylene blue.

  15. Development studies for a novel wet oxidation process. Phase 2

    International Nuclear Information System (INIS)

    DETOXSM is a catalyzed wet oxidation process which destroys organic materials in an acidic water solution of iron at 373 to 473 K. The solution can be used repeatedly to destroy great amounts of organic materials. Since the process is conducted in a contained vessel, air emissions from the process can be well controlled. The solution is also capable of dissolving and concentrating many heavy and radioactive metals for eventual stabilization and disposal. The Phase 2 effort for this project is site selection and engineering design for a DETOX demonstration unit. Site selection was made using a set of site selection criteria and evaluation factors. A survey of mixed wastes at DOE sites was conducted using the Interim Mixed Waste Inventory Report. Sites with likely suitable waste types were identified. Potential demonstration sites were ranked based on waste types, interest, regulatory needs, scheduling, ability to provide support, and available facilities. Engineering design for the demonstration unit is in progress and is being performed by Jacobs Applied Technology. The engineering design proceeded through preliminary process flow diagrams (PFDs), calculation of mass and energy balances for representative waste types, process and instrumentation diagrams (P and IDs), preparation of component specifications, and a firm cost estimate for fabrication of the demonstration unit

  16. Wet Oxidation Pre-Treatment – the Way To Improve Economics of Energy Production From Manure?

    DEFF Research Database (Denmark)

    Uellendahl, Hinrich; Mladenovska, Zuzana; Langvad, Niels Bo;

    2006-01-01

    and Wheatley, 1993). The combination of high temperature and pressure, together with the addition of oxygen in the wet oxidation process, has shown a superior potential for increasing the hydrolysis of lignocellulosic biomass with subsequent ethanol fermentation. In the present study the wet oxidation...... process was tested as pretreatment for increasing the biogas yield of the fiber fraction of manure. The wet oxidation pretreatment in combination with solid liquid separation of manure by using either chemical precipitation or decanter centrifuge (Møller et al., 2004) could be a promising option for a...

  17. A novel advanced oxidation process——wet electrocatalytic oxidation for high concentrated organic wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    DAI QiZhou; ZHOU MingHua; LEI LeCheng; ZHANG Xing Wang

    2007-01-01

    A novel advanced oxidation process-wet electrocatalytic oxidation(WEO)was studied with p-nitrophenol as model pollutant and β-PbO2 electrode as the anode.Compared with the effect of the individual wet air oxidation(WAO)and electrochemical oxidation(EO),the effect of WEO showed synergistic effect on COD removal under the conditions of temperature 160℃,C=1000mg·L-1,PN2=0.50MPa,Po2=0.9 MPa,current density=3 mA·cm-2,Na2SO4 3 g·L-1.And the synergistic factor got the best value of 0.98 within 120 min after 180 min treatment.The synergistic factor was studied after 120 min treatment at 100℃,120℃,140℃and 160℃,and the effect of 120℃was the best with the value of 1.26.Possible mechanism for the synergistic effect was discussed based on the analysis of free-radical generation and intermediates detected by HPLC and GC/MS.

  18. The Study of LeachateTreatment by Using Three Advanced Oxidation Process Based Wet air Oxidation

    Directory of Open Access Journals (Sweden)

    Behroz Karimi

    2013-01-01

    Full Text Available 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[degree sign] 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.

  19. Wet deposition of oxidized nitrogen in the United States Pacific Northwest for 2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This spatial data set was created by the U.S. Geological Survey (USGS) to represent the amount of wet deposition of oxidized nitrogen in the Pacific Northwest...

  20. A kinetic model of municipal sludge degradation during non-catalytic wet oxidation.

    Science.gov (United States)

    Prince-Pike, Arrian; Wilson, David I; Baroutian, Saeid; Andrews, John; Gapes, Daniel J

    2015-12-15

    Wet oxidation is a successful process for the treatment of municipal sludge. In addition, the resulting effluent from wet oxidation is a useful carbon source for subsequent biological nutrient removal processes in wastewater treatment. Owing to limitations with current kinetic models, this study produced a kinetic model which predicts the concentrations of key intermediate components during wet oxidation. The model was regressed from lab-scale experiments and then subsequently validated using data from a wet oxidation pilot plant. The model was shown to be accurate in predicting the concentrations of each component, and produced good results when applied to a plant 500 times larger in size. A statistical study was undertaken to investigate the validity of the regressed model parameters. Finally the usefulness of the model was demonstrated by suggesting optimum operating conditions such that volatile fatty acids were maximised. PMID:26426294

  1. Thermal wet oxidation improves anaerobic biodegradability of raw and digested biowaste

    DEFF Research Database (Denmark)

    Lissens, G.; Thomsen, Anne Belinda; De Baere, L.;

    2004-01-01

    Anaerobic digestion of solid biowaste generally results in relatively low methane yields of 50-60% of the theoretical maximum. Increased methane recovery from organic waste would lead to reduced handling of digested solilds, lower methane emissions to the environment, and higher green energy....... Measured methane yields for raw yard waste, wet oxidized yard waste, raw food waste, and wet oxidized food waste were 345, 685, 536, and 571 mL of CH4/g of volatile suspended solids, respectively. Higher oxygen pressure during wet oxidation of digested biowaste considerably increased the total methane...... profits. The objective of this research was to enhance the anaerobic biodegradability and methane yields from different biowastes (food waste, yard waste, and digested biowaste already treated in a full-scale biogas plant (DRANCO, Belgium)) by assessing thermal wet oxidation. The biodegradability of the...

  2. CATALYTIC WET AIR OXIDATION OF INDUSTRIAL EFFLUENTS USING A Pt CATALIST SUPPORTED ON MULTIWALLED CARBON NANOTUBES

    OpenAIRE

    Gabriel Ovejero; José L. Sotelo; Araceli Rodríguez; Ana Vallet; Juan García

    2011-01-01

    In this work, catalytic wet air oxidation in a batch reactor was studied by catalytic wet air oxidation to treat industrial wastewater. Basic Yellow 11, a basic dye, was employed as a model compound and platinum supported over multi-walled nanotubes (Pt/MWNT) was used as catalyst. Additionally, two different industrial wastewaters were tested. The results prove the high effectivity of this treatment, showing high extents of total organic carbon and toxicity removal of the final effluent. We c...

  3. Development Studies for a Novel Wet Oxidation Process

    Energy Technology Data Exchange (ETDEWEB)

    Delphi Research

    1999-09-30

    DETOX is a catalyzed wet oxidation process that destroys organic materials in an acidic water solution of iron at 373 to 473 K. The solution can be used repeatedly to destroy great amounts of organic materials. Since the process is conducted in a contained vessel, air emissions from the process can be well controlled. The solution is also capable of dissolving and concentrating many heavy and radioactive metals for eventual stabilization and disposal. The Phase III effort for this project is fabrication, assembly, and installation of the DETOX demonstration unit, preparation of documentation and training to meet site requirements for operation, followed by system run-in and shakedown testing of the unit prior to demonstration testing. The Title III design was completed and the unit was fabricated according to standards set forth by OSHA, EPA, the American Petroleum Institute (i.e., chemical and petroleum industry standards), and the ASME B-313 Piping Code requirements as agreed to in preliminary design meetings with primary stakeholders. The unit was assembled in three modules and two trailers and then shipped to the TNX facility at the Savannah River Site in September and october of 1996. On-going site integration tasks were address while delays in installation arose due to funding sources and costs. In March of 1997, Delphi was authorized to proceed with the installation of the unit, making electrical and mechanical connections necessary to operate the unit. All installation tasks were completed in August of 1997. Results of an Operational Readiness Review conducted in August 1997 verified that Delphi's procedures and documentation met the necessary requirements to operate the unit at SRS. Completion of the final checklist of WSRC requirements was then addressed including the Owner's Independent Inspection Report, verifying all components of the unit met B-31.3 standards. Final hydraulic and pneumatic tests were completed in November to satisfy the B-31

  4. CuO impregnated activated carbon for catalytic wet peroxide oxidation of phenol

    International Nuclear Information System (INIS)

    This paper presents an original approach to the removal of phenol in synthetic wastewater by catalytic wet peroxide oxidation with copper binding activated carbon (CuAC) catalysts. The characteristics and oxidation performance of CuAC in the wet hydrogen peroxide catalytic oxidation of phenol were studied in a batch reactor at 80 deg. C. Complete conversion of the oxidant, hydrogen peroxide, was observed with CuAC catalyst in 20 min oxidation, and a highly efficient phenol removal and chemical oxygen demand (COD) abatement were achieved in the first 30 min. The good oxidation performance of CuAC catalyst was contributed to the activity enhancement of copper oxide, which was binding in the carbon matrix. It can be concluded that the efficiency of oxidation dominated by the residual H2O2 in this study. An over 90% COD removal was achieved by using the multiple-step addition in this catalytic oxidation.

  5. Soluble Moringa oleifera leaf extract reduces intracellular cadmium accumulation and oxidative stress in Saccharomyces cerevisiae.

    Science.gov (United States)

    Kerdsomboon, Kittikhun; Tatip, Supinda; Kosasih, Sattawat; Auesukaree, Choowong

    2016-05-01

    Moringa oleifera leaves are a well-known source of antioxidants and traditionally used for medicinal applications. In the present study, the protective action of soluble M. oleifera leaf extract (MOLE) against cadmium toxicity was investigated in the model eukaryote Saccharomyces cerevisiae. The results showed that this extract exhibited a protective effect against oxidative stress induced by cadmium and H2O2 through the reduction of intracellular reactive oxygen species. Interestingly, not only the co-exposure of soluble MOLE with cadmium but also pretreatment of this extract prior to cadmium exposure significantly reduced the cadmium uptake through an inhibition of Fet4p, a low-affinity iron(II) transporter. In addition, the supplementation of soluble MOLE significantly reduced intracellular iron accumulation in a Fet4p-independent manner. Our findings suggest the potential use of soluble extract from M. oleifera leaves as a dietary supplement for protection against cadmium accumulation and oxidative stress. PMID:26675819

  6. Kinetics study on catalytic wet air oxidation of phenol by several metal oxide catalysts

    Institute of Scientific and Technical Information of China (English)

    WAN Jia-feng; FENG Yu-jie; CAI Wei-min; YANG Shao-xia; SUN Xiao-jun

    2004-01-01

    Four metal oxide catalysts composed of copper (Cu), stannum (Sn), copper-stannum (Cu-Sn) and copper-cerium(Cu-Ce) respectively were prepared by the co-impregnation method, and γ-alumina(γ-Al2O3) is selected as support. A first-order kinetics model was established to study the catalytic wet air oxidation of phenol at different temperature when these catalysts were used. The model simulations are good agreement with present experimental data. Results showed that the reaction rate constants can be significantly increased when catalysts were used, and the catalyst of 6% Cu-10%Ce/γ-Al2O3 showed the best catalytic activity. This is consistent with the result of catalytic wet air oxidation of phenol and the COD removal can be arrived at 98.2% at temperature 210℃, oxygen partial pressure 3 MPa and reaction time 30 min. The activation energies of each reaction with different catalysts are nearly equal, which is found to be about 42 kJ/mol and the reaction in this study is proved to be kinetics control.

  7. Comparison between wet oxidation and steam explosion as pretreatment methods for enzymatic hydrolysis of sugarcane bagasse

    DEFF Research Database (Denmark)

    Medina, Carlos Martín; Marcet, M.; Thomsen, Anne Belinda

    2008-01-01

    Alkaline wet oxidation and steam explosion pretreatments of sugarcane bagasse were compared with regard to biomass fractionation, formation of by-products, and enzymatic convertibility of the pretreated material. Wet oxidation led to the solubilisation of 82% of xylan and 50% of lignin, and to a...... fraction than steam explosion did. A better enzymatic convertibility of cellulose was achieved for the wet-oxidised material (57.4 %) than for the steam-exploded material (48.9 %). Cellulose convertibility was lower for the whole slurry than for the washed solids in both pretreatments, but more...

  8. Magnetic carbon xerogels for the catalytic wet peroxide oxidation of 4-nitrophenol solutions

    OpenAIRE

    Ribeiro, R; Silva, Adrián; Faria, Joaquim; Gomes, Helder

    2015-01-01

    Catalytic wet peroxide oxidation (CWPO) is a well-known advanced oxidation process for the removal of organic pollutants from industrial process waters and wastewater. Specifically, CWPO employs hydrogen peroxide (H2O2) as oxidation source and a suitable catalyst to promote its decomposition via formation of hydroxyl radicals (HO•), which exhibit high oxidizing potential and serve as effective species in the destruction of a huge range of organic pollutants

  9. Oxidative stress and alterations in actin cytoskeleton trigger glutathione efflux in Saccharomyces cerevisiae.

    Science.gov (United States)

    Bradamante, Silvia; Villa, Alessandro; Versari, Silvia; Barenghi, Livia; Orlandi, Ivan; Vai, Marina

    2010-12-01

    A marked deficiency in glutathione (GSH), the most abundant antioxidant in living systems, plays a major role in aging and the pathogenesis of diseases ranging from neurological disorders to early atherosclerosis and the impairment of various immunological functions. In an attempt to shed light on GSH homeostasis, we carried out the space experiment SCORE (Saccharomyces cerevisiae oxidative stress response evaluation) during the FOTON-M3 mission. Microgravity and hyperoxic conditions induced an enormous extracellular release of GSH from S. cerevisiae cells (≈40% w/dw), changed the distribution of the buds, and activated the high osmolarity glycerol (HOG) and cell integrity/PKC pathways, as well as protein carbonylation. The results from the single spaceflight experiment were validated by a complete set of experiments under conditions of simulated microgravity and indicate that cytoskeletal alterations are mainly responsible for the observed effects. The results of ground experiments in which we induced cytoskeletal modifications by means of treatment with dihydrocytochalasin B (DHCB), a potent inhibitor of actin polymerisation, or (R)-(+)-trans-4-(1-aminoethyl)-N-(4-pyridyl)cyclohexanecarboxamide dihydrochloride monohydrate (Y-27632), a selective ROCK (Rho-associated coiled-coil forming protein serine/threonine kinase) inhibitor, confirmed the role of actin in GSH efflux. We also found that the GSH release can be inhibited using the potent chloride channel blocker 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB). PMID:20708643

  10. Wet strength improvement of unbleached kraft pulp through laccase catalyzed oxidation.

    Science.gov (United States)

    Lund, M; Felby, C

    2001-06-01

    Previous investigations have shown that laccase catalyzed oxidation of lignin containing wood fibers can enhance the strength of medium density fiberboards. In the present work it was investigated if laccase treatment had any impact on the tensile strength of a high yield unbleached kraft pulp. Treatment with laccase alone had only a very little effect on the wet strength of the pulp, whereas addition of lignin rich extractives increased the wet strength after the enzyme treatment significantly. A mediated oxidation gave a similar improvement of the wet tensile strength although no lignin was added to the fiber suspension. Furthermore, it was found that a heat treatment combined with a mediated oxidation gave a higher improvement in wet tensile strength than could be accounted for by the individual treatments. No change in dry tensile strength from the laccase treatment was observed. It is suggested that the observed improvement in wet tensile strength is related to polymerization of lignin on fibers in the hand sheet and/or coupling of phenoxy radicals on lignin associated to adjacent fibers. For the different mediators studied, a correlation was found between oxygen consumption upon mediated oxidation and generation of wet strength in the pulp. PMID:11397456

  11. Measurement of the oxidation-extraction of uranium from wet-process phosphoric acid

    International Nuclear Information System (INIS)

    The present invention relates to processes for the recovery of uranium from wet-process phosphoric acid and more particularly to the oxidation-extraction steps in the DEPA-TOPO process for such recovery. A more efficient use of oxidant is obtained by monitoring the redox potential during the extraction step

  12. An approach to modeling of silicon oxidation in a wet ultra-diluted ambient

    NARCIS (Netherlands)

    Kovalgin, A.Y.; Hof, A.J.; Schmitz, J.

    2005-01-01

    In this work, we make steps towards developing a new wet-oxidation model of silicon based on electron-stimulated dissociation of H2O molecules. The need for a new model arises from the fact that existing physical models are inadequate to describe the thin-oxide regime. Two regimes of silicon oxidati

  13. Degradation of quinoline by wet oxidation - kinetic aspects and reaction mechanisms

    DEFF Research Database (Denmark)

    Thomsen, A.B.

    1998-01-01

    The high temperature, high pressure wet oxidation reaction of quinoline has been studied as a function of initial concentration, pH and temperature. At neutral to acidic pH, it is effective in the oxidation of quinoline at 240 degrees C and above, whereas under alkaline conditions the reaction is...... markedly slowed down. The results indicate that the reaction is an auto-catalysed, free radical chain reaction transforming 99% of quinoline to other substances. Of the quinoline. 30-50% was oxidised to CO2 and H2O depending on the initial concentration. Wet oxidation of deuterium-labelled quinoline was...

  14. Development of a Catalytic Wet Air Oxidation Method to Produce Feedstock Gases from Waste Polymers

    Science.gov (United States)

    Kulis, Michael J.; Guerrero-Medina, Karen J.; Hepp, Aloysius F.

    2012-01-01

    Given the high cost of space launch, the repurposing of biological and plastic wastes to reduce the need for logistical support during long distance and long duration space missions has long been recognized as a high priority. Described in this paper are the preliminary efforts to develop a wet air oxidation system in order to produce fuels from waste polymers. Preliminary results of partial oxidation in near supercritical water conditions are presented. Inherent corrosion and salt precipitation are discussed as system design issues for a thorough assessment of a second generation wet air oxidation system. This work is currently being supported by the In-Situ Resource Utilization Project.

  15. The Oxidation of AlN in Dry and Wet Oxygen

    Science.gov (United States)

    Opila, Elizabeth; Humphrey, Donald; Jacobson, Nathan; Yoshio, Tetsuo; Oda, Kohei

    1998-01-01

    The oxidation kinetics of AlN containing 3.5 wt% Y2O3 were studied by thermogravimetric analysis in dry oxygen and 10% H2O/balance oxygen at temperatures between 1000 and 1200 C for times between 48 and 100 h. The oxidation kinetics for AlN in dry oxygen were parabolic and of approximately the same magnitude and temperature dependence as other alumina forming materials. In this case, diffusion of oxygen and/or aluminum through the alumina scale is the rate limiting mechanism. The oxidation kinetics for AlN in wet oxygen were nearly linear and much more rapid than rates observed in dry oxygen. Numerous micropores were observed in the alumina formed on AIN in wet oxygen. These pores provide a fast path for oxygen transport. The linear kinetics observed in this case suggest that the interface reaction rate of AlN with wet oxygen is the oxidation rate limiting step.

  16. Key parameters when developing carbonaceous materials for catalytic wet peroxide oxidation

    OpenAIRE

    Ribeiro, Rui; Silva, Adrián; Pastrana-Martínez, Luisa; Figueiredo, José; Faria, Joaquim; Gomes, Helder

    2014-01-01

    Catalytic wet peroxide oxidation (CWPO) is an advanced oxidation process, operated using simple equipment and mild operating conditians, in which highly oxidizing hydraxyl radicaIs (HO') are generated fram the catalytic decompasition af hydrogen peroxide (H,O,) [L 2). Sinee the report of Lüeking el ai. in 1998 [3], the develapment af suitab-Ie -carbonaceous materials (without any added metal phase) for CWPO has been intensively explored [4). lhe influenee of struetUfal and surr...

  17. Response to different oxidants of Saccharomyces cerevisiae ure2Delta mutant.

    Science.gov (United States)

    Todorova, Tatina T; Petrova, Ventsislava Y; Vuilleumier, Stéphane; Kujumdzieva, Anna V

    2009-11-01

    Growth of Saccharomyces cerevisiae ure2Delta mutant strain was investigated in the presence of diverse oxidant compounds. The inability of the strain to grow on a medium supplemented with H(2)O(2) was confirmed and a relationship between diminishing levels of glutathione (GSH) and peroxide sensitivity was established. Data for the lack of significant effect of URE2 disruption on the cellular growth in the presence of paraquat and menadione were obtained. The possible role of Ure2p in acquiring sensitivity to oxidative stress by means of its regulatory role in the GATA signal transduction pathway was discussed. It was suggested that the susceptibility of ure2Delta mutant to the exogenous hydrogen peroxide can result from increased GSH degradation due to the deregulated localization of the gamma-glutamyl transpeptidase activating factors Gln3/Gat1. The important role of Ure2p in in vivo glutathione-mediated reactive oxygen species (ROS) scavenging was shown by measuring the activity of antioxidant enzymes glutathione peroxidase, superoxide dismutase (SOD) and catalase in an URE2 disrupted strain. A time-dependent increase in SOD and catalase activity was observed. More importantly, it was shown that the ure2 mutation could cause significant disturbance in cellular oxidant balance and increased ROS level. PMID:19777209

  18. Combination of coagulation and catalytic wet oxidation for the treatment of pulp and paper mill effluents.

    Science.gov (United States)

    Verenich; Laari, A; Nissen, M; Kallas, J

    2001-01-01

    Wet oxidation (WO) is a well established process for purification of concentrated municipal and industrial wastewaters. Many attempts have been made to modify the WO process or to create a suitable combination of processes. This work was undertaken to investigate wet oxidation integrated with coagulation, i.e. to treat the sludge remaining after coagulation with a WO process. The possibility of regeneration of the used coagulant was also considered. Two waters from paper mills were used: TMP (thermomechanical pulp) circulation water and membrane concentrate. About 50% of the COD in the original water can be removed by coagulation using Fe2(SO4)3. The results from the wet oxidation experiments show the positive effect of iron in the chemical sludge as a catalyst. The efficiency of the WO process was enhanced almost by 100%. The remaining dissolved organic matter can be easily removed biologically. PMID:11695452

  19. COMPARISON BETWEEN WET OXIDATION AND STEAM EXPLOSION AS PRETREATMENT METHODS FOR ENZYMATIC HYDROLYSIS OF SUGARCANE BAGASSE

    Directory of Open Access Journals (Sweden)

    Carlos Martín

    2008-08-01

    Full Text Available Alkaline wet oxidation and steam explosion pretreatments of sugarcane bagasse were compared with regard to biomass fractionation, formation of by-products, and enzymatic convertibility of the pretreated material. Wet oxidation led to the solubilisation of 82% of xylan and 50% of lignin, and to a two-fold increase of cellulose content in the pretreated solids, while steam explosion solubilised only 60% of xylan and 35% of lignin and increased cellulose content in the solid material by one third. Wet oxidation formed more aliphatic acids and phenolics, and less furan aldehydes in the liquid fraction than steam explosion did. A better enzymatic convertibility of cellulose was achieved for the wet-oxidised material (57.4 % than for the steam-exploded material (48.9 %. Cellulose convertibility was lower for the whole slurry than for the washed solids in both pretreatments, but more significantly in steam explosion. This investigation demonstrates the potential of wet oxidation as a promising pretreatment method for enzyme-based bagasse-to-ethanol processes.

  20. Improved wet peroxide oxidation strategies for the treatment of chlorophenols

    OpenAIRE

    Muñoz, Macarena; de Pedro, Zahara M.; Casas, José Antonio; Rodríguez, Juan José

    2013-01-01

    Different advanced oxidation strategies have been investigated for the treatment of chlorophenols in aqueous phase with the aim of improving the removal efficiency in terms of mineralization, remanent by-products and kinetics. Those strategies were homogeneous Fenton-like oxidation and CWPO with two different own-prepared FexOy/γ-Al2O3 catalysts. The intensification of the process by increasing the temperature has been also evaluated. CWPO of chlorophenols with those catalysts has proved to b...

  1. A novel oxidation-based wet etching method for AlGaN/GaN heterostructures

    Institute of Scientific and Technical Information of China (English)

    Cai Jinbao; Wang Jinyan; Liu Yang; Xu Zhe; Wang Maojun; Yu Min; Xie Bing

    2013-01-01

    A novel wet etching method for AlGaN/GaN heterojunction structures is proposed using thermal oxidation followed by wet etching in KOH solution.It is found that an AlGaN/GaN heterostructure after high temperature oxidation above 700 ℃ could be etched off in a homothermal (70 ℃) KOH solution while the KOH solution had no etching effects on the region of the A1GaN/GaN heterostructure protected by a SiO2 layer during the oxidation process.A groove structure with 150 nm step depth on an AlGaN/GaN heterostructure was formed after 8 h thermal oxidation at 900 ℃ followed by 30 min treatment in 70 ℃ KOH solution.As the oxidation time increases,the etching depth approaches saturation and the roughness of the etched surface becomes much better.The physical mechanism of this phenomenon is also discussed.

  2. Pretreatment of Reed by Wet Oxidation and Subsequent Utilization of the Pretreated Fibers for Ethanol Production

    DEFF Research Database (Denmark)

    Szijarto, Nora; Kádár, Zsófia; Varga, Eniko;

    2009-01-01

    lignocelluloses usually do. In the present study, wet oxidation was investigated as the pretreatment method to enhance the enzymatic digestibility of reed cellulose to soluble sugars and thus improve the convertibility of reed to ethanol. The most effective treatment increased the digestibility of reed cellulose...... by cellulases more than three times compared to the untreated control. During this wet oxidation, 51.7% of the hemicellulose and 58.3% of the lignin were solubilized, whereas 87.1% of the cellulose remained in the solids. After enzymatic hydrolysis of pretreated fibers from the same treatment, the...

  3. Formation and degradation of valuable intermediate products during wet oxidation of municipal sludge.

    Science.gov (United States)

    Baroutian, Saeid; Gapes, Daniel J; Sarmah, Ajit K; Farid, Mohammed M; Young, Brent R

    2016-04-01

    The current study investigated the formation of organic acids and alcohols as major intermediate products of wet oxidation of municipal sludge. Municipal sludge was subjected to 60-min wet oxidation at temperatures ranging from 220 to 240°C, with 20bar oxygen partial pressure. Acetic acid was the main intermediate compound produced in this study, followed by propionic, n-butyric, iso-butyric and pentanoic acids and methanol. It was found that the process severity has a significant influence on the formation and degradation of these intermediate products. PMID:26832394

  4. Preparation of rare-earth metal complex oxide catalysts for catalytic wet air oxidation

    Institute of Scientific and Technical Information of China (English)

    LI Ning; LI Guangming; YAO Zhenya; ZHAO Jianfu

    2007-01-01

    Catalytic wet air oxidation(CWAO)is one of the most promising technologies for pollution abatement.Developing catalysts with high activity and stability is crucial for the application of the CWAO process.The Mn/Ce complex oxide catalyrsts for CWAO of high concentration phenol containing wastewater were prepared by coprecipitation.The catalyst preparation conditions were optimized by using an orthogonal layout method and single-factor experimental analysis.The Mn/Ce serial catalysts were characterized by Brunauer-Emmett-Teller(BET)analysis and the metal cation leaching was measured by inductively coupled plasma torch-atomic emission spectrometry(ICP-AES).The results show that the catalysts have high catalytic activities even at a low temperature(80℃)and low oxygen partial pressure(0.5 MPa)in a batch reactor.The metallic ion leaching is comparatively low(Mn<6.577 mg/L and Ce<0.6910 mg/L,respectively)in the CWAO process.The phenol,CODCD and TOC removal efficiencies in the solution exceed 98.5% using the optimal catalyst(named CSP).The new catalyst would have a promising application in CWAO treatment of high concentration organic wastewater.

  5. Wet oxidation behaviors of polycrystalline Si1-xGex films

    International Nuclear Information System (INIS)

    We investigated the oxidation behaviors of poly Si1-xGex films with a 15% and 42% Ge content. The films were deposited using ultrahigh vacuum chemical vapor deposition on a 1000 Aa thick thermal SiO2 layer, and were oxidized using a conventional furnace in wet oxygen ambient at 700 and 800 deg. C. The physical and chemical properties of the oxide were analyzed by using Rutherford backscattering spectrometry, x-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy before and after the oxidation. We observed that the Ge content in the oxide layer and oxidation rate increased with the increase of Ge content in poly Si1-xGex films. We also observed that Ge content in the oxide layer decreased with the increase of oxidation temperature

  6. Influence the oxidant action of selenium in radiosensitivity induction and cell death in yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Ionizing radiations are from both natural sources such as from anthropogenic sources. Recently, radiotherapy has emerged as one of the most common therapies against cancer. Co-60 irradiators (cobalt-60 linear accelerators) are used to treat of malignant tumors routinely in hospitals around the world. Exposure to ionizing radiation can induce changes in cellular macromolecules and affect its functions, because they cause radiolysis of the water molecule generating reactive oxygen species, which can cause damage to virtually all organelles and cell components known as oxidative damage that can culminate in oxidative stress. Oxidative stress is a situation in which the balance between oxidants and antioxidants is broken resulting in excessive production of reactive species, it is not accompanied by the increase in antioxidant capacity, making it impossible to neutralize them. Selenium is a micronutrient considered as antioxidant, antiinflammatory, which could prevent cancer. Selenium in biological system exists as seleno proteins. Nowadays, 25 human seleno proteins have been identified, including glutathione peroxidase, an antioxidant enzyme. Yeasts have the ability to incorporate various metals such as iron, cadmium, zinc and selenium, as well as all biological organisms. The yeast Saccharomyces cerevisiae, unlike mammalian cells is devoid of seleno proteins, being considered as a practical model for studies on the toxicity of selenium, without any interference from the metabolism of seleno proteins. Moreover, yeast cells proliferate through the fermentation, the microbial equivalent of aerobic glycolysis in mammals and the process is also used by tumors. Several reports show that the pro-oxidante effects and induced toxic selenium compounds occur at lower doses and in malignant cells compared with benign cells. Therefore selenium giving a great therapeutic potential in cancer treatment .Our objective was to determine whether selenium is capable to sensitize yeasts

  7. Fabrication and characterization of a novel zinc oxide thin film piezoelectric micocantilever with wet etching method

    OpenAIRE

    Bhatia, Deepak; Sharma, Himanshu; Nawaz, S.; Meena, R. S.; Tomy, C. V.; Palkar, V. R.

    2015-01-01

    In this work the fabrication and characterization of a novel zinc oxide thin film piezoelectric micocantilever with wet etching method have been reported for the first time ever. The piezoelectric zinc oxide (ZnO) thin film was deposited using dielectric (RF magnetron) sputtering method. The crystalline structures, surface roughness (morphology) and charge reversal of ZnO film are evaluated by X-ray Diffractometer (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM), re...

  8. Orange II removal by catalytic wet peroxide oxidation using activated carbon xerogels

    OpenAIRE

    Pinho, Maria; Silva, Adrián; Fathy, Nady; Attia, Amina; Gomes, Helder; Faria, Joaquim

    2013-01-01

    Orange II is a synthetic dye widely employed in the textile industry and responsible for serious environrnentaI cancerns. Dyes like this urge the development af new technologies for the treatment af wastewaters generated in this industrial activity. Those include catalytic wet peroxide oxidation (CWPO), which is an advanced oxidation process (AOP) based on the generation of hydroxyl radicais (I-lO·) from hydrogen peroxide with tlle aid ofa suitable catalysl [I].

  9. VAPOR-PHASE CRACKING AND WET OXIDATION AS POTENTIAL POLLUTANT CONTROL TECHNIQUES FOR COAL GASIFICATION

    Science.gov (United States)

    The report gives results of an investigation of two techniques (hydrocracking of heavy organics in the raw gas prior to quency, and wet oxidation of the gasifier condensate) for pollutant control in coal gasification processes. Bench-scale experiments were used to determine rates...

  10. Design, fabrication and testing of a wet oxidation waste processing system. [for manned space flight

    Science.gov (United States)

    1975-01-01

    The wet oxidation of sewage sludge during space flight was studied for water and gas recovery, and the elimination of overboard venting. The components of the system are described. Slurry and oxygen supply modules were fabricated and tested. Recommendations for redesign of the equipment are included.

  11. Ethanol production from maize silage as lignocellulosic biomass in anaerobically digested and wet-oxidized manure

    DEFF Research Database (Denmark)

    Oleskowicz-Popiel, Piotr; Lisiecki, P.; Holm-Nielsen, J.B.;

    2008-01-01

    investigated using 2 1 bioreactors. Wet oxidation performed for 20 min at 121 degrees C was found as the most suitable pretreatment conditions for AD manure. High ammonia concentration and significant amount of macro- and micro-nutrients in the AD manure had a positive influence on the ethanol fermentation. No...

  12. Development studies of a novel wet oxidation process

    International Nuclear Information System (INIS)

    Many DOE waste streams and remediates contain complex and variable mixtures of organic compounds, toxic metals, and radionuclides. These materials are often dispersed in organic or inorganic matrices, such as personal protective equipment, various sludges, soils, and water. Incineration and similar combustive processes do not appear to be viable options for treatment of these waste streams due to various considerations. There is a need for non-combustion processes with a wide application range to treat the large majority of these waste forms. The non-combustion process should also be safe, effective, cost-competitive, permit-able, and preferrably mobile. This paper describes the DETOX process of organic waste oxidation

  13. Pretreatment of wheat straw using combined wet oxidation and alkaline hydrolysis resulting in convertible cellulose and hemicellulose

    DEFF Research Database (Denmark)

    Bjerre, A.B.; Bjerring Olesen, A.; Fernqvist, T.;

    1996-01-01

    The wet oxidation process of wheat straw has been studied as a pretreatment method to attain our main goal: To break down cellulose to glucose enzymatic, and secondly, to dissolve hemicellulose (e.g., for fermentation) without producing microbial inhibitors. Wet oxidation combined with base addit...

  14. Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gary Blythe; Conor Braman; Katherine Dombrowski; Tom Machalek

    2010-12-31

    This document is the final technical report for Cooperative Agreement DE-FC26-04NT41992, 'Pilot Testing of Mercury Oxidation Catalysts for Upstream of Wet FGD Systems,' which was conducted over the time-period January 1, 2004 through December 31, 2010. The objective of this project has been to demonstrate at pilot scale the use of solid catalysts and/or fixed-structure mercury sorbents to promote the removal of total mercury and oxidation of elemental mercury in flue gas from coal combustion, followed by wet flue gas desulfurization (FGD) to remove the oxidized mercury at high efficiency. The project was co-funded by the U.S. DOE National Energy Technology Laboratory (DOE-NETL), EPRI, Great River Energy (GRE), TXU Energy (now called Luminant), Southern Company, Salt River Project (SRP) and Duke Energy. URS Group was the prime contractor. The mercury control process under development uses fixed-structure sorbents and/or catalysts to promote the removal of total mercury and/or oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone FGD systems. Oxidized mercury not adsorbed is removed in the wet FGD absorbers and leaves with the byproducts from the FGD system. The project has tested candidate materials at pilot scale and in a commercial form, to provide engineering data for future full-scale designs. Pilot-scale catalytic oxidation tests have been completed for periods of approximately 14 to19 months at three sites, with an additional round of pilot-scale fixed-structure sorbent tests being conducted at one of those sites. Additionally, pilot-scale wet FGD tests have been conducted downstream of mercury oxidation catalysts at a total of four sites. The sites include the two of three sites from this project and two sites where catalytic oxidation pilot testing was conducted as part of a previous DOE-NETL project. Pilot-scale wet FGD tests were also conducted at a fifth site, but with no catalyst or fixed

  15. Characteristics of titania supported copper oxide catalysts for wet air oxidation of phenol

    International Nuclear Information System (INIS)

    Various techniques have been used to characterize the CuO x/TiO2 catalysts with different copper loading. Surface area, pore volume and pore size distribution of the prepared catalysts were estimated from nitrogen adsorption isotherm. Temperature programmed reduction (TPR), X-ray diffraction (XRD), electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES) experiments were performed to investigate the chemical state of the copper species. The chemical state of copper in the CuO x/TiO2 catalysts varied with copper loading (1-25 wt.%): highly dispersed Cu2+ cluster for 1 and 5 wt.%, and bulk CuO for 7-25 wt.%. The activity and mineralization selectivity of the CuO x/TiO2 catalysts increased with copper loading up to 20 wt.%, and remained almost constant for higher copper loading. The optimum copper loading was 20 wt.% for the wet air oxidation of phenol over the CuO x/TiO2 catalysts in this work. The stability of the CuO x/TiO2 catalysts with different copper loading was also studied with respect to carbonaceous deposits and copper leaching

  16. Catalytic wet oxidation of thiocyanate with homogeneous copper(II) sulphate catalyst

    International Nuclear Information System (INIS)

    The wet oxidation of thiocyanate has been investigated in a semi-batch reactor at temperatures between 423 and 473 K and pressures between 6.1 x 103 and 1.0 x 104 kPa in the presence of copper(II) sulphate as catalyst. The effects of copper concentration, initial thiocyanate concentration, pressure and temperature on the reaction rate were analyzed and the main products of reaction were identified. A kinetic model for the Cu-catalyzed reaction is here proposed, including temperature, oxygen concentration, and the reduction of Cu2+ to Cu+ that gives an accurate prediction of the oxidation process under the assayed conditions. A mechanistic model based on the formation of a transition complex between a copper cation and two thiocyanate anions has been proposed for the catalytic wet oxidation.

  17. Development studies of a novel wet oxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, T.W.; Dooge, P.M.

    1996-12-31

    The objective of this study is to develop a novel catalytic chemical oxidation process that can be used to effectively treat multi-component wastes with a minimum of pretreatment characterization, thus providing a versatile, non-combustion method which will destroy hazardous organic compounds while simultaneously containing and concentrating toxic and radioactive metals for recovery or disposal in a readily stabilized matrix. Although the DETOX{sup SM} process had been tested to a limited extent for potential application to mixed wastes, there had not been sufficient experience with the process to determine its range of application to multicomponent waste forms. The potential applications of the process needed to be better identified. Then, the process needed to be demonstrated on wastes and remediate types on a practical scale in order that data could be obtained on application range, equipment size, capital and operating costs, effectiveness, safety, reliability, permittability, and potential commercial applications of the process. The approach for the project was, therefore, to identify the potential range of applications of the process (Phase I), to choose demonstration sites and design a demonstration prototype (Phase II), to fabricate and shakedown the demonstration unit (Phase III), then finally to demonstrate the process on surrogate hazardous and mixed wastes, and on actual mixed wastes (Phase IV).

  18. Oxidation Kinetics of Chemically Vapor-Deposited Silicon Carbide in Wet Oxygen

    Science.gov (United States)

    Opila, Elizabeth J.

    1994-01-01

    The oxidation kinetics of chemically vapor-deposited SiC in dry oxygen and wet oxygen (P(sub H2O) = 0.1 atm) at temperatures between 1200 C and 1400 C were monitored using thermogravimetric analysis. It was found that in a clean environment, 10% water vapor enhanced the oxidation kinetics of SiC only very slightly compared to rates found in dry oxygen. Oxidation kinetics were examined in terms of the Deal and Grove model for oxidation of silicon. It was found that in an environment containing even small amounts of impurities, such as high-purity Al2O3 reaction tubes containing 200 ppm Na, water vapor enhanced the transport of these impurities to the oxidation sample. Oxidation rates increased under these conditions presumably because of the formation of less protective sodium alumino-silicate scales.

  19. Catalytic wet oxidation of ammonia solution: Activity of the nanoscale platinum-palladium-rhodium composite oxide catalyst

    International Nuclear Information System (INIS)

    Aqueous solutions of 400-1000 mg/L of ammonia were oxidized in a trickle-bed reactor (TBR) in this study of nanoscale platinum-palladium-rhodium composite oxide catalysts, which were prepared by the co-precipitation of H2PtCl6, Pd(NO3)3 and Rh(NO3)3. Hardly any of the dissolved ammonia was removed by wet oxidation in the absence of any catalyst, whereas about 99% of the ammonia was reduced during wet oxidation over nanoscale platinum-palladium-rhodium composite oxide catalysts at 503 K in an oxygen partial pressure of 2.0 MPa. A synergistic effect exists in the nanoscale platinum-palladium-rhodium composite structure, which is the material with the highest ammonia reduction activity. The nanometer-sized particles were characterized by TEM, XRD and FTIR. The effect of the initial concentration and reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid hourly space velocity of under 9 h-1 in the wet catalytic processes

  20. Effect of Alloying Additions on the Oxidation of High Speed Steels under Dry and Wet Conditions

    Institute of Scientific and Technical Information of China (English)

    F.C. RIZZO; M.J.MONTEIRO; S.R.J.SAUNDERS

    2009-01-01

    An investigation has been carried out into the effects of chromium and vanadium content on the oxidation rate and on the adhesion of oxide scales grown on three different chemical compositions of high speed steels under dry and wet conditions. The oxidation tests were carried out in a thermobalance at 650 ℃ for up to 14.4 ks. The mass gain of the specimens increased with increasing contents of water vapour. Alloy composition had no effect on the oxidation rate in dry conditions. The "adhesion" of the oxide scale was determined using indentation with a Rockwell C diamond and the pull adhesion test to determine the interfacial toughness and the tensile strength of the oxide metal bond, respectively. Generally, the results of the investigation indicated that oxide adhesion was lowest for the specimens exposed to dry conditions, and that with increasing water vapour content, the scale was more adherent. Indentation test results showed that an increase in the Ⅴ concentration was deleterious to oxidc adhesion in both the dry and wet environments, whereas an increase in the Cr-content had little effect on adhesion.

  1. Phytoxicity study of the products of wet oxidation of a representative biomass (lettuce)

    Science.gov (United States)

    Onisko, B. L.; Wydeven, T.

    1983-01-01

    In an attempt to verify the results reported previously concerning the phytotoxicity of wet-oxidation (wet-ox) products, lettuce solids were suspended in water and then heated to 548 K for 3.6 ksec (1 hr) under 4.1x10 to the -7 Pa (400 psig at 294 K) oxygen pressure and 1.52x10 to the 8th (1500 psig at 548 K) total pressure. Such treatment resulted in oxidation of 80% of the initial organic carbon to carbon dioxide. Thirty-three percent of the remaining organic carbon was present in acetic acid. Organic nitrogen in the feed was decreased 90% by the wet-ox treatment. Ammonia and nitrogen gas were the main nitrogen products. Analysis of the liquid product of wet-ox indicated that most of the minerals essential for plant growth were present. However, when tested using a lettuce-root growth-rate assay, the solution was toxic. This toxicity was not due to excessive salt or ammonia or to an improper pH. Analysis of the wet-ox solution revealed the presence of silver and chromium, thus implicating reactor corrosion as the cause of the phytotoxicity. Both cation and anion exchange resins removed the silver and the toxicity of the liquid effluent, indicating silver as the toxic component. Uptake of both silver and chromium by lettuce roots correlated with diminished root growth. Toxicity of the solution from wet-ox was not observed when precautions were taken to minimize contact of the liquid in the reactor with the metal reactor components.

  2. Modifications of oxidized Zircaloy-4 surface in contact with radiolysed wet air

    Energy Technology Data Exchange (ETDEWEB)

    Guipponi, C. [Universite de Lyon, Institut de Physique Nucleaire de Lyon, Universite Claude Bernard Lyon 1, CNRS UMR5822, 4 rue Enrico Fermi, 69 622 Villeurbanne Cedex (France); Millard-Pinard, N., E-mail: millard@ipnl.in2p3.fr [Universite de Lyon, Institut de Physique Nucleaire de Lyon, Universite Claude Bernard Lyon 1, CNRS UMR5822, 4 rue Enrico Fermi, 69 622 Villeurbanne Cedex (France); Bererd, N. [Universite de Lyon, Institut de Physique Nucleaire de Lyon, Universite Claude Bernard Lyon 1, CNRS UMR5822, 4 rue Enrico Fermi, 69 622 Villeurbanne Cedex (France); Universite de Lyon, UCBL-IUT Lyon 1, departement chimie, 43 Bd du 11 novembre 1918, F-69622 Villeurbanne Cedex (France); Serris, E.; Pijolat, M.; Peres, V. [Ecole Nationale Superieure des Mines de Saint Etienne, Centre SPIN, CNRS UMR5148, 158 cours Fauriel, 42 033 Saint Etienne Cedex (France); Wasselin-Trupin, V. [Institut de Radioprotection et de Surete Nucleaire, BP. 17, 92 262 Fontenay aux Roses (France)

    2012-02-01

    In the framework of radioactive waste geological disposal, the long term evolution of the nuclear wastes packages and the release of the radionuclides from the wastes have to be studied. Regarding compacted wastes (cladding tubes) coming from reprocessing of spent fuel, the Zircaloy-4 (zirconium alloy) cladding tubes have been activated and oxidized in reactors. In the disposal, the radioactive waste is exposed to humid air in a first phase and to water after the resaturation phase. In order to better assess the degradation process of these nuclear waste package, the influence of wet air proton radiolysis on the behavior of surface oxidized Zircaloy-4 has been investigated. Radiolysis experiments were performed using an irradiation cell which is associated to an extracted beam. Samples are exposed to wet air, under and without radiolysis, during 12 and 24 h. The water partial pressure has been fixed at 6 and 50 mbar in order to have, respectively, localized adsorbed water molecules and a thin film of adsorbed water. Before and after each treatment, sample surfaces were characterized by X-ray Photoelectron Spectroscopy (XPS) in order to identify the elements at the topmost surface of the solid. The wet air radiolysis causes changes at the surface of oxidized Zircaloy-4 and influences the corrosion phenomenon. Indeed, an enrichment of tin and the presence of nitrogen species were observed. It could be due to the formation of tritin(II) tetrahydroxide dinitrate and a Zr{sup 4+} tetramer on the topmost oxide surface.

  3. Differential response of ammonia-oxidizing archaea and bacteria to the wetting of salty arid soil.

    Science.gov (United States)

    Sher, Yonatan; Ronen, Zeev; Nejidat, Ali

    2016-08-01

    Ammonia-oxidizing archaea and bacteria (AOA, AOB) catalyze the first and rate-limiting step of nitrification. To examine their differential responses to the wetting of dry and salty arid soil, AOA and AOB amoA genes (encoding subunit A of the ammonia monooxygenase) and transcripts were enumerated in dry (summer) and wet (after the first rainfall) soil under the canopy of halophytic shrubs and between the shrubs. AOA and AOB were more abundant under shrub canopies than between shrubs in both the dry and wetted soil. Soil wetting caused a significant decrease in AOB abundance under the canopy and an increase of AOA between the shrubs. The abundance of the archaeal amoA gene transcript was similar for both the wet and dry soil, and the transcript-to-gene ratios were amoA transcript-to-gene ratios were between 78 and 514. The lowest ratio was in dry soil under the canopy and the highest in the soil between the shrubs. The results suggest that the AOA are more resilient to stress conditions and maintain a basic activity in arid ecosystems, while the AOB are more responsive to changes in the biotic and abiotic conditions. PMID:27037935

  4. Effect of oxidizing agents on selenate formation in a wet FGD

    Energy Technology Data Exchange (ETDEWEB)

    Hiroyuki Akiho; Shigeo Ito; Hiromitsu Matsuda [Central Research Institute of Electric Power Industry (CRIEPI), Kanagawa (Japan). Energy Engineering Research Laboratory

    2010-09-15

    In a coal combustion process, a considerable amount of selenium is captured in the wet FGD, where it is oxidized from selenite to selenate, which is difficult to remove. Diethyl-p-phenylene-diammonium (DPD) absorptiometric analysis and ion chromatography identified peroxodisulfate ion (S{sub 2}O{sub 8}{sup 2-}) as the dominant oxidizing agent in the FGD liquor. Selenite was easily oxidized to selenate in the presence of S{sub 2}O{sub 8}{sup 2-} and the oxidation was accelerated as the temperature increased. Addition of Mn{sup 2+} ion was found to be effective in controlling selenate formation. When Mn{sup 2+} ion was added, oxidized not selenite to selenate but rather Mn{sup 2+} to MnO{sub 2}, which captured some dissolved selenite. 13 refs., 9 figs. 1 tab.

  5. Transcriptomics in human blood incubation reveals the importance of oxidative stress response in Saccharomyces cerevisiae clinical strains

    Directory of Open Access Journals (Sweden)

    Llopis Silvia

    2012-08-01

    Full Text Available Abstract Background In recent years an increasing number of yeast infections in humans have been related to certain clinical isolates of Saccharomyces cerevisiae. Some clinical strains showed in vivo and in vitro virulence traits and were able to cause death in mice whereas other clinical strains were avirulent. Results In this work, we studied the transcriptional profiles of two S. cerevisiae clinical strains showing virulent traits and two control non-virulent strains during a blood incubation model and detected a specific transcriptional response of clinical strains. This response involves an mRNA levels increase of amino acid biosynthesis genes and especially oxidative stress related genes. We observed that the clinical strains were more resistant to reactive oxygen species in vitro. In addition, blood survival of clinical isolates was high, reaching similar levels to pathogenic Candida albicans strain. Furthermore, a virulent strain mutant in the transcription factor Yap1p, unable to grow in oxidative stress conditions, presented decreased survival levels in human blood compared with the wild type or YAP1 reconstituted strain. Conclusions Our data suggest that this enhanced oxidative stress response in virulent clinical isolates, presumably induced in response to oxidative burst from host defense cells, is important to increase survival in human blood and can help to infect and even produce death in mice models.

  6. Treatment of desizing wastewater from the textile industry by wet air oxidation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper describes the application of wet air oxidation to the treatment of desizing wastewater from two textile companies. A two-liter high temperature, high pressure autoclave reactor was used in the study. The range of operating temperatures examined was between 150 and 290℃, and the partial pressure of oxygen ranged from 0. 375 to 2.25 MPa. Variations in pH,CODCr and TOD content were monitored during each experiment and used to assess the extent of conversion of the process. The effects of temperature, pressure and reaction time were explored extensively. More than 90 % CODCr reduction and 80 % TOC removal have been obtained. The results have also been demonstrated that WAO is a suitable pre-treatment methods due to improvement of the BOD5/CODCr ratio of desizing wastewater. The reaction kinetics of wet air oxidation of desizing wastewater has been proved to be two steps, a fast reaction followed by a slow reaction stage.

  7. Kinetics and Modelling of Glucose Wet Air Oxidation over Pd/C Catalyst.

    Czech Academy of Sciences Publication Activity Database

    Gogová, Zuzana; Zedníková, Mária; Hanika, Jiří

    Bratislava: Slovak Society of Chemical Engineering, 2007 - (Markoš, J.; Štefuca, V.), s. 309 ISBN 978-80-227-2640-5. [International Conference of Slovak Society of Chemical Engineering /34./. Tatranské Matliare (SK), 21.05.2007-25.05.2007] R&D Projects: GA ČR(CZ) GD203/03/H140 Institutional research plan: CEZ:AV0Z40720504 Keywords : glucose * wet air oxidation * kinetics Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  8. Toluene removal by oxidation reaction in spray wet scrubber: experimental, modeling and optimization

    OpenAIRE

    Roumporn Nikom; Juntima Chungsiriporn; Charun Bunyakan

    2006-01-01

    Toluene, an important volatile organic compound (VOC), is used in many kinds of industries, such as painting, printing, coating, and petrochemical industries. The emission of toluene causes serious air pollution, odor problem, flammability problem and affects human health. This paper proposes the removal of toluene from waste air using a spray wet scrubber combining the absorption and oxidation reaction. Aqueous sodium hypochlorite (NaOCl) solution was used as the scrubbing liquid in the syst...

  9. Kinetics of wet oxidation of phenol over an Fe/activated carbon catalyst

    NARCIS (Netherlands)

    Quintanilla, A.; Casas, J.A.; Rodriquez, J.J.; Kreutzer, M.T.; Kapteijn, F.; Moulijn, J.A.

    2007-01-01

    Wet oxidation of phenol over an Fe/activated carbon catalyst has been studied in a trickle-bed reactor in the following operational window: inlet C phenol=0.5 and 1 g/L, T=100-127 ºC, PT=3-8 atm, W=0-4.8 g, QL=0.125-2 mL/min and QO2=91.6 NmL/min. The experiments were carried out in the absence of ma

  10. Carbon nanotubes: a suitable material for catalytic wet peroxide oxidation of organic pollutants?

    OpenAIRE

    Ribeiro, Rui; Silva, Adrián; Faria, Joaquim; Gomes, Helder

    2012-01-01

    Carbon materials, such as activated carbons (AC), graphite and activated carbon xerogels, have been explored as metal-free catalysts for the catalytic wet peroxide oxidation (CWPO) of bio-refractory organic compounds, such as azo dyes and phenolic compounds [1-3]. At the same time, the application of carbon nanomaterials in catalysis, such as carbon nanotubes (CNT), has grown exponentially [4]. In the present work, commercial multiwalled carbon nanotubes (MWNT) were used in the CWPO of 2-nitr...

  11. The influence of carbon material properties on the efficiency of catalytic wet peroxide oxidation processes

    OpenAIRE

    Gomes, Helder; R. Ribeiro; Silva, Adrián; Figueiredo, José; Faria, Joaquim

    2015-01-01

    Carbon materiais are well known catalysts for activatin§ H^O^ into hydroxyl radicais (HO'), which are efficient oxidizin § agents. By making use of highly reactive HO" radicais, the elimination of organic compounds can be accomplished by catalytic wet peroxide oxidation (CWPO), a water treatment technology operating under mild conditions of pressure and temperature that hás gained importance due to the decreasing cost of H;0; and its increasing use in wastewater treatm...

  12. Development and testing of a wet oxidation waste processing system. [for waste treatment aboard manned spacecraft

    Science.gov (United States)

    Weitzmann, A. L.

    1977-01-01

    The wet oxidation process is considered as a potential treatment method for wastes aboard manned spacecraft for these reasons: (1) Fecal and urine wastes are processed to sterile water and CO2 gas. However, the water requires post-treatment to remove salts and odor; (2) the residual ash is negligible in quantity, sterile and easily collected; and (3) the product CO2 gas can be processed through a reduction step to aid in material balance if needed. Reaction of waste materials with oxygen at elevated temperature and pressure also produces some nitrous oxide, as well as trace amounts of a few other gases.

  13. Wet oxidation lumped kinetic model for wastewater organic burden biodegradability prediction.

    Science.gov (United States)

    Verenich, Svetlana; Kallas, Juha

    2002-08-01

    In many cases, treatment of wastewaters requires a combination of processes that very often includes biological treatment. Wet oxidation (WO) in combination with biotreatment has been successfully used for the treatment of refractory wastes. Therefore, information about the biodegradability of wastewater solutes and particulates after wet oxidation is very important. The present work proposes a model that can describe the oxidation process via organic concentration characteristics such as chemical oxygen demand (COD), biochemical oxygen demand (BOD), and immediately available BOD (IA BOD) and so can allow the prediction of biodegradability (i.e., BOD/COD ratio). The reaction mechanism includes the destruction of nonbiodegradable substances bytwo pathways: oxidation to carbon dioxide and water and oxidation to larger biodegradable compounds with their further degradation to smaller ones measured via IA BOD. The destruction of small biodegradable compounds to end products is also included in the model. The experiments were performed at different temperatures (170-200 degrees C) and partial oxygen pressures (0.5-1.5 MPa) in a batch stainless steel high-pressure autoclave. The model of concentrated thermomechanical pulp circulation water was selected for the experiments. The proposed model correlates with the experimental data well and it is compared with other WO models in the literature. PMID:12188362

  14. Influence of Substrate Particle Size and Wet Oxidation on Physical Surface Structures and Enzymatic Hydrolysis of Wheat Straw

    DEFF Research Database (Denmark)

    Pedersen, Mads; Meyer, Anne S.

    2009-01-01

    microscopy images of the straw particles revealed edged, nonspherical, porous particles with variable surface structures as a result of the grinding. Wet oxidation pretreatment tore up the surface structures of the particles to retain vascular bundles of xylem and phloem. The enzymatic hydrolysis left behind......In the worldwide quest for producing biofuels from lignocellulosic biomass, the importance of the substrate pretreatment is becoming increasingly apparent. This work examined the effects of reducing the substrate particle sizes of wheat straw by grinding prior to wet oxidation and enzymatic...... hydrolysis. The yields of glucose and xylose were assessed after treatments with a benchmark cellulase system consisting of Celluclast 1.5 L (Trichoderma reesei) and Novozym 188 -glucosidase (Aspergillus niger). Both wet oxidized and not wet oxidized wheat straw particles gave increased glucose release with...

  15. High Temperature Behavior of Oxidized Mild Steel in Dry and Wet Atmospheres

    International Nuclear Information System (INIS)

    During the hot rolling process, steels develop an oxide scale on their surface. This scale can affect the mechanical properties of the rolled steel and its surface aspect. The main problem comes from the mechanical integrity of the oxide scales which could delaminate or crack, leading eventually to later oxide incrustation within the steel. The objective of the present work is to qualify the mechanical integrity of the iron oxide scales during the hot rolling process. The laboratory experiments use a four point bending test to simulate the mechanical solicitation which takes place during the rolling sequence of the steel slabs. The oxide scales grow on a mild steel at 900 .deg. C under wet or dry atmosphere and the oxidized steel is then mechanically tested at 900 .deg. C or 700 .deg. C. The high temperature four point bending tests are completed with microstructural observations and with the record of acoustic emission to follow in-situ the mechanical damages of the oxide scales. The results show the role of water vapor which promotes the scale adherence, and the role of the temperature as the oxide are more damaged at 700 .deg. C than at 900 .deg. C

  16. Study on dynamics characteristics of wet air oxidation of non-ionic surfactants

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Wet air oxidation is an effective method to deal with highly concentrated nondegradable emulsification wastewater which contains non-ionic surfactants. This article illustrates our investigation on dynamic characteristics of wet air oxidation of typical non-ionic surfactants like polyether, phenol ether and widely used alcohol ether. The experimental results indicated that the oxidation rate of polyether, phenol ether and alcohol ether obviously ascended as the temperature rose. A good oxidation effect was available at 240℃. The TOC removal rate could reach 88.0%, 94% and 91.5%, after 125 min reaction. Alcohol ether was prone to an easier oxidation compared with polyether and phenol ether when the temperature was 220℃ or below. The oxidation rate of alcohol ether was higher than that of polyether at 160℃, while the oxidation rate of polyether was higher than that of phenol ether between 180℃ and 220℃. During the later period of the reaction at 240℃, the rate of phenol ether was higher than that of alcohol ether, which was still higher than that of polyether. Partitioned first order kinetics model analy-sis showed that the apparent activation energy of alcohol ether was lower than that of both polyether and phenol ether in the leading stage and lagging stage, and it was easy to acquire a higher oxidation rate for alcohol ether at low temperature. Three parameter general dynamics model analyses showed that the reason why the oxidation rate of polyether was lower than that of alcohol ether was that the oxidation of polyether was more apt to be converted to intermediate production than that of alcohol ether, whereas between 200℃ and 220℃, the direct oxidation rate of polyether and the oxidation rate of intermediate product were obviously lower than that of alcohol ether. The apparent activation energy of direct and indirect oxidation of polyether was 43.37 and 60.45 kJ?mol?1, respectively, while the corre-sponding apparent activation energy of alcohol

  17. Study on dynamics characteristics of wet air oxidation of non-ionic surfactants

    Institute of Scientific and Technical Information of China (English)

    ZENG XinPing; TANG WenWei; ZHAO JianFu; GU GuoWei

    2008-01-01

    Wet air oxidation is an effective method to deal with highly concentrated nondegradable emulsification wastewater which contains non-ionic surfactants. This article illustrates our investigation on dynamic characteristics of wet air oxidation of typical non-ionic surfactants like polyether, phenol ether and widely used alcohol ether. The experimental results indicated that the oxidation rate of polyether, phenol ether and alcohol ether obviously ascended as the temperature rose. A good oxidation effect was available at 240℃. The TOC removal rate could reach 88.0%, 94% and 91.5%, after 125 min reaction. Alcohol ether was prone to an easier oxidation compared with polyether and phenol ether when the temperature was 220℃ or below. The oxidation rate of alcohol ether was higher than that of polyether at 160℃, while the oxidation rate of polyether was higher than that of phenol ether between 180℃ and 220℃. During the later period of the reaction at 240℃, the rate of phenol ether was higher than that of alcohol ether, which was still higher than that of polyether. Partitioned first order kinetics model analysis showed that the apparent activation energy of alcohol ether was lower than that of both polyether and phenol ether in the leading stage and lagging stage, and it was easy to acquire a higher oxidation rate for alcohol ether at low temperature. Three parameter general dynamics model analyses showed that the reason why the oxidation rate of polyether was lower than that of alcohol ether was that the oxidation of polyether was more apt to be converted to intermediate production than that of alcohol ether, whereas between 200℃ and 220℃, the direct oxidation rate of polyether and the oxidation rate of intermediate product were obviously lower than that of alcohol ether. The apparent activation energy of direct and indirect oxidation of polyether was 43.37 and 60.45 kJ·mol-1, respectively, while the corresponding apparent activation energy of alcohol

  18. Catalytic wet peroxide oxidation of phenol solutions over CuO/CeO2 systems

    International Nuclear Information System (INIS)

    Three 5% CuO/CeO2 catalysts were synthesized by sol-gel, precipitation and combustion methods, followed by incipient wetness impregnation with copper nitrate. The samples were characterized by XRD, TPR, BET and tested for the catalytic wet peroxide oxidation of a phenol solution (5 g/L). The reaction took place in a batch reactor at atmospheric pressure, in a temperature range of 60-80°C , during 4 h. Phenol conversion, H2O2 consumption, pH and chemical oxygen demand were determined. The reaction temperature and the catalyst loading did improve the phenol and the H2O2 conversions. The effect on the selectivity towards complete mineralization was less marked, with levels among 60-70%. Stepwise addition of H2O2 was also tested.

  19. Real-time in situ monitoring of wet thermal oxidation for precise confinement in VCSELs

    International Nuclear Information System (INIS)

    A new imaging method is presented enabling the monitoring of the lateral wet thermal oxidation of a thin Al-containing layer embedded in a vertical cavity lasers (VCSEL) structure. This method is based on the measurement of the modification of the VCSEL reflectivity spectrum inherent to the aperture layer refractive index change, with an observation window restricted to the wavelength ranges for which this reflectivity variation is maximal. The main purpose is the accurate control of the buried confinement aperture, and, thereby, that of the electro-optical characteristics of the laser device. The kinetics of the lateral oxidation has been studied for small-size aperture VCSEL (3–10 µm) and for long-range oxidation depths. This straightforward method based on an optical imaging system will enable robust improvement of the production yield of this multifactor-dependent technological process

  20. Chloride interference in the analysis of dissolved organic carbon by the wet oxidation method

    Science.gov (United States)

    Aiken, G.R.

    1992-01-01

    The presence of Cl- in concentrations greater than 0.02 M is shown to interfere with the analysis of aqueous DOC concentrations by the wet oxidation method of analysis when a reaction time of 5 min is employed. Chloride competes with DOC for S2O82-, lowering the overall oxidation efficiency. The resulting HOCl from the oxidation of Cl- reacts with DOC, producing significant amounts of chlorinated intermediate compounds in addition to CO2. These compounds were found in the waste effluent from the reaction chamber and in the gas stream transporting CO2 to the detector. While a possible Cl- effect has been noted for DOC measurements in the past, it has not previously been demonstrated to be a source of error at the concentrations reported in this paper. The interference can be overcome either by increasing the digestion time or by diluting samples to contain less than 0.02 M Cl-.

  1. Full-Scale Testing of a Mercury Oxidation Catalyst Upstream of a Wet FGD System

    Energy Technology Data Exchange (ETDEWEB)

    Gary Blythe; Jennifer Paradis

    2010-06-30

    This document presents and discusses results from Cooperative Agreement DE-FC26-06NT42778, 'Full-scale Testing of a Mercury Oxidation Catalyst Upstream of a Wet FGD System,' which was conducted over the time-period July 24, 2006 through June 30, 2010. The objective of the project was to demonstrate at full scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in pulverized-coal-fired flue gas. Oxidized mercury is removed downstream in wet flue gas desulfurization (FGD) absorbers and collected with the byproducts from the FGD system. The project was co-funded by EPRI, the Lower Colorado River Authority (LCRA), who also provided the host site, Great River Energy, Johnson Matthey, Southern Company, Salt River Project (SRP), the Tennessee Valley Authority (TVA), NRG Energy, Ontario Power and Westar. URS Group was the prime contractor and also provided cofunding. The scope of this project included installing and testing a gold-based catalyst upstream of one full-scale wet FGD absorber module (about 200-MW scale) at LCRA's Fayette Power Project (FPP) Unit 3, which fires Powder River Basin coal. Installation of the catalyst involved modifying the ductwork upstream of one of three wet FGD absorbers on Unit 3, Absorber C. The FGD system uses limestone reagent, operates with forced sulfite oxidation, and normally runs with two FGD modules in service and one spare. The full-scale catalyst test was planned for 24 months to provide catalyst life data. Over the test period, data were collected on catalyst pressure drop, elemental mercury oxidation across the catalyst module, and mercury capture by the downstream wet FGD absorber. The demonstration period began on May 6, 2008 with plans for the catalyst to remain in service until May 5, 2010. However, because of continual increases in pressure drop across the catalyst and concerns that further increases would adversely affect Unit 3 operations, LCRA decided to end the

  2. Wet oxidative degradation of cellulosic wastes 5- chemical and thermal properties of the final waste forms

    International Nuclear Information System (INIS)

    In this study, the residual solution arising from the wet oxidative degradation of solid organic cellulosic materials, as one of the component of radioactive solid wastes, using hydrogen peroxide as oxidant. Were incorporated into ordinary Portland cement matrix. Leaching as well as thermal characterizations of the final solidified waste forms were evaluated to meet the final disposal requirements. Factors, such as the amount of the residual solution incorporated, types of leachant. Release of different radionuclides and freezing-thaw treatment, that may affect the leaching characterization. Were studied systematically from the data obtained, it was found that the final solid waste from containing 35% residual solution in tap water is higher than that in ground water or sea water. Based on the data obtained from thermal analysis, it could be concluded that incorporating the residual solution form the wet oxidative degradation of cellulosic materials has no negative effect on the hydration of cement materials and consequently on the thermal stability of the final solid waste from during the disposal process

  3. Application of Catalytic Wet Air Oxidation to Treatment of Landfill Leachate on Co/Bi Catalyst

    Institute of Scientific and Technical Information of China (English)

    LI Hai-sheng; LIU Liang; ZHANG Rong; DONG De-ming; LIU Hong-liang; LI Yu

    2004-01-01

    Catalytic wet air oxidation(CWAO) was employed to reduce the organic compounds in landfill leachate and the effects of temperature, oxygen pressure, catalyst dosage, and concentration of the organic compounds on the TOC and CODCr removal rates were studied. The degradation kinetics of landfill leachate was also investigated and an exponential experiential model consisting of four influential factors was established to describe the reduction of the organic compounds in the landfill leachate. Meanwhile, the GC-MS technique was used to detect the components of the organic intermediates for the inference of the decomposition mechanisms of the organic compounds in landfill leachate. The results reveal that the reaction temperature and the catalyst dosage are the most important factors affecting the degradation reaction of the organic compounds and that the principal intermediates confirmed by GC-MS are organic acids at a percentage of more than 88% with no aldehydes or alcohols detected. The decomposition mechanisms of the organic compounds in landfill leachate were inferred based on the GC-MS information as follows: the activated gas phase O2 captured the hydrogen of the organic pollutants to produce free radicals, which then initiated the catalytic reaction. So most of the organic compounds were oxidized into CO2 and H2O ultimately. In general, catalytic wet air oxidation over catalyst Co3O4/Bi2O3 was a very promising technique for the treatment of landfill leachate.

  4. An analytical method for 14C in environmental water based on a wet-oxidation process.

    Science.gov (United States)

    Huang, Yan-Jun; Guo, Gui-Yin; Wu, Lian-Sheng; Zhang, Bing; Chen, Chao-Feng; Zhang, Hai-Ying; Qin, Hong-Juan; Shang-Guan, Zhi-Hong

    2015-04-01

    An analytical method for (14)C in environmental water based on a wet-oxidation process was developed. The method can be used to determine the activity concentrations of organic and inorganic (14)C in environmental water, or total (14)C, including in drinking water, surface water, rainwater and seawater. The wet-oxidation of the organic component allows the conversion of organic carbon to an inorganic form, and the extraction of the inorganic (14)C can be achieved by acidification and nitrogen purging. Environmental water with a volume of 20 L can be used for the wet-oxidation and extraction, and a detection limit of about 0.02 Bq/g(C) can be achieved for water with carbon content above 15 mg(C)/L, obviously lower than the natural level of (14)C in the environment. The collected carbon is sufficient for measurement with a low level liquid scintillation counter (LSC) for typical samples. Extraction or recovery experiments for inorganic carbon and organic carbon from typical materials, including analytical reagents of organic benzoquinone, sucrose, glutamic acid, nicotinic acid, humic acid, ethane diol, et cetera., were conducted with excellent results based on measurement on a total organic carbon analyzer and LSC. The recovery rate for inorganic carbon ranged tween 98.7%-99.0% with a mean of 98.9(± 0.1)%, for organic carbon recovery ranged between 93.8% and 100.0% with a mean of 97.1(± 2.6)%. Verification and an uncertainty budget of the method are also presented for a representative environmental water. The method is appropriate for (14)C analysis in environmental water, and can be applied also to the analysis of liquid effluent from nuclear facilities. PMID:25590997

  5. An analytical method for 14C in environmental water based on a wet-oxidation process

    International Nuclear Information System (INIS)

    An analytical method for 14C in environmental water based on a wet-oxidation process was developed. The method can be used to determine the activity concentrations of organic and inorganic 14C in environmental water, or total 14C, including in drinking water, surface water, rainwater and seawater. The wet-oxidation of the organic component allows the conversion of organic carbon to an inorganic form, and the extraction of the inorganic 14C can be achieved by acidification and nitrogen purging. Environmental water with a volume of 20 L can be used for the wet-oxidation and extraction, and a detection limit of about 0.02 Bq/g(C) can be achieved for water with carbon content above 15 mg(C)/L, obviously lower than the natural level of 14C in the environment. The collected carbon is sufficient for measurement with a low level liquid scintillation counter (LSC) for typical samples. Extraction or recovery experiments for inorganic carbon and organic carbon from typical materials, including analytical reagents of organic benzoquinone, sucrose, glutamic acid, nicotinic acid, humic acid, ethane diol, et cetera., were conducted with excellent results based on measurement on a total organic carbon analyzer and LSC. The recovery rate for inorganic carbon ranged tween 98.7%–99.0% with a mean of 98.9(±0.1)%, for organic carbon recovery ranged between 93.8% and 100.0% with a mean of 97.1(±2.6)%. Verification and an uncertainty budget of the method are also presented for a representative environmental water. The method is appropriate for 14C analysis in environmental water, and can be applied also to the analysis of liquid effluent from nuclear facilities. - Highlights: • An analytical method of 14C in environmental water was developed. • Extraction or recovery experiments were conducted with excellent results. • Verification and uncertainty assessment was presented

  6. Hydrogen content of underwater wet welds deposited by rutile and oxidizing electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Pope, A.M. [PETROBRAS Research and Development Center, Rio de Janeiro (Brazil); Liu, S. [Colorado School of Mines, Golden, CO (United States). Center for Welding, Joining and Coatings Research

    1996-12-01

    Shielded metal arc wet welding, due to its flexibility and ease of mobilization, is one of the most attractive methods for repair of underwater structures. However, the quality of the weld metals deposited by this process is detrimentally affected by the direct contact of the welding arc with the aqueous environment. Oxygen and hydrogen generated by the decomposition of water in the arc are responsible for the main problems related to this specific process: loss of deoxidizers, oxygen pickup, increase in oxide inclusions content, hydrogen-induced cracking, and porosity. Rutile electrodes are recognized in the literature as being able to deposit welds with adequate mechanical properties but with high hydrogen content. Oxidizing electrodes, on the other hand, are able to deposit welds with lower hydrogen content but higher oxygen content. Welds deposited by rutile electrodes presented approximately 90 ml/100g of diffusible hydrogen while oxidizing electrodes produced welds with diffusible hydrogen contents varying from 40 to 50 ml/100g. It was found that the measured diffusible hydrogen contents of underwater wet welds are more dependent on the type of electrode covering than on the weld metal oxygen content. The residual hydrogen content of underwater welds showed a tendency to increase to a constant level of approximately 5 ml/100g as the oxygen content of the weld increased to the saturation value (0.22 wt.pct.). It seems, therefore, that the diffusible hydrogen content of underwater wet welds is more influenced by the amount of total hydrogen absorbed by the liquid metal before solidification than by the amount of inclusions, acting as hydrogen traps, in the weld metal.

  7. Chloride ions promoted the catalytic wet peroxide oxidation of phenol over clay-based catalysts.

    Science.gov (United States)

    Zhou, Shiwei; Zhang, Changbo; Xu, Rui; Gu, Chuantao; Song, Zhengguo; Xu, Minggang

    2016-01-01

    Catalytic wet peroxide oxidation (CWPO) of phenol over clay-based catalysts in the presence and absence of NaCl was investigated. Changes in the H2O2, Cl(-), and dissolved metal ion concentration, as well as solution pH during phenol oxidation, were also studied. Additionally, the intermediates formed during phenol oxidation were detected by liquid chromatography-mass spectroscopy and the chemical bonding information of the catalyst surfaces was analyzed by X-ray photoelectron spectroscopy (XPS). The results showed that the presence of Cl(-) increased the oxidation rate of phenol to 155%, and this phenomenon was ubiquitous during the oxidation of phenolic compounds by H2O2 over clay-based catalysts. Cl(-)-assisted oxidation of phenol was evidenced by several analytical techniques such as mass spectroscopy (MS) and XPS, and it was hypothesized that the rate-limiting step was accelerated in the presence of Cl(-). Based on the results of this study, the CWPO technology appears to be promising for applications in actual saline phenolic wastewater treatment. PMID:26942523

  8. Surface activation of thin silicon oxides by wet cleaning and silanization

    International Nuclear Information System (INIS)

    Silanization protocols for glass slides and silicon oxide substrates usually include acid rinsing steps to activate the surfaces prior to silanization. In our group, field-effect transistor devices and electrolyte-insulator-semiconductor structures are used to electronically record signals from cells or to detect biomolecular interactions at the solid-liquid interface. A miniaturized, high sensitive, field-effect-based semiconductor device should expose at its input stage just a thin oxide (< 10 nm) to the electrolyte solution. Therefore, silanization protocols are needed, which do not alter the thin oxide layers in terms of topology changes or thickness loss. In this article we evaluated different protocols for wet cleaning and activation of thin silicon oxides. The efficiency of the cleaning methods was verified with Contact Angle Measurements, Atomic Force Microscopy, and Fourier-Transform Infrared Spectroscopy. Furthermore, X-ray Photoelectron Spectroscopy was used to characterize the oxides after the cleaning and silanization procedures. (3-aminopropyl)triethoxysilane was used to functionalize the oxide surfaces for further attachment of biological molecules (e.g. proteins, DNA). Thicknesses and uniformity of the silane coatings were evaluated by Imaging Ellipsometry

  9. Kinetics of wet peroxide oxidation of phenol with a gold/activated carbon catalyst

    OpenAIRE

    Domínguez, Carmen M.; Quintanilla, Asunción; Casas, José Antonio; Rodríguez, Juan José

    2014-01-01

    Gold nanoparticles supported on activated carbon (Au/AC) have been tested in catalytic wet peroxide oxidation using phenol as target pollutant. In the current work, the effect of several operating conditions, including initial pH (3.5–10.5), catalyst load (0–6 g/L), initial phenol concentration (0.1–5 g/L), hydrogen peroxide dose (4–100% of the theoretical stoichiometric amount) and reaction temperature (50–80 °C) has been investigated. The results show that the Au/AC catalyst would be useful...

  10. Ethanol production from wet oxidized corn straw by simultaneous saccharification and fermentation

    DEFF Research Database (Denmark)

    Zhang, Q.; Yin, Y.; Thygesen, Anders;

    2010-01-01

    In order to find out the appropriate process for ethanol production from corn straw, alkaline wet-oxidation pretreatment (195°C, 15 min, Na2CO3 2 g/L, O2 1200 kPa) and simultaneous saccharification and fermentation (SSF) were adopted to produce ethanol. The results showed that 90% of cellulose...... obtained. The estimated total ethanol production was 262.7 kg/t raw material by assuming the consumption of both C-6 and C-5. No obvious inhibition effect occurred during SSF. These offered experiment evidences for ethanol production from corn straw....

  11. Pretreatment of corn stover using wet oxidation to enhance enzymatic digestibility

    DEFF Research Database (Denmark)

    Varga, E.; Schmidt, A.S.; Reczey, K.;

    2003-01-01

    Corn stover is an abundant, promising raw material for fuel ethanol production. Although it has a high cellulose content, without pretreatment it resists enzymatic hydrolysis, like most lignocellulosic materials. Wet oxidation (water, oxygen, mild alkali or acid, elevated temperature and pressure......) was investigated to enhance the enzymatic digestibility of corn stover. Six different combinations of reaction temperature, time, and pH were applied. The best conditions (60 g/L of corn stover, 195degreesC, 15 min, 12 bar O-2, 2 g/L of Na2CO) increased the enzymatic conversion of corn stover four...

  12. Development of Pillared Clays for Wet Hydrogen Peroxide Oxidation of Phenol and Its Application in the Posttreatment of Coffee Wastewater

    OpenAIRE

    Nancy R. Sanabria; Rafael Molina; Sonia Moreno

    2012-01-01

    This paper focuses on the use of pillared clays as catalysts for the Fenton-like advanced oxidation, specifically wet hydrogen peroxide catalytic oxidation (WHPCO). This paper discusses the limitations on the application of a homogeneous Fenton system, development of solid catalysts for the oxidation of phenol, advances in the synthesis of pillared clays, and their potential application as catalysts for phenol oxidation. Finally, it analyzes the use of pillared clays as heterogeneous Fenton-l...

  13. Development of Pillared Clays for Wet Hydrogen Peroxide Oxidation of Phenol and Its Application in the Posttreatment of Coffee Wastewater

    Directory of Open Access Journals (Sweden)

    Nancy R. Sanabria

    2012-01-01

    Full Text Available This paper focuses on the use of pillared clays as catalysts for the Fenton-like advanced oxidation, specifically wet hydrogen peroxide catalytic oxidation (WHPCO. This paper discusses the limitations on the application of a homogeneous Fenton system, development of solid catalysts for the oxidation of phenol, advances in the synthesis of pillared clays, and their potential application as catalysts for phenol oxidation. Finally, it analyzes the use of pillared clays as heterogeneous Fenton-like catalysts for a real wastewater treatment, emphasizing the oxidation of phenolic compounds present in coffee wastewater. Typically, the wet hydrogen peroxide catalytic oxidation in a real effluent system is used as pretreatment, prior to biological treatment. In the specific case of coffee wet processing wastewater, catalytic oxidation with pillared bentonite with Al-Fe is performed to supplement the biological treatment, that is, as a posttreatment system. According to the results of catalytic activity of pillared bentonite with Al-Fe for oxidation of coffee processing wastewater (56% phenolic compounds conversion, 40% selectivity towards CO2, and high stability of active phase, catalytic wet hydrogen peroxide oxidation emerges as a viable alternative for management of this type of effluent.

  14. Catalytic and non-catalytic wet air oxidation of sodium dodecylbenzene sulfonate: kinetics and biodegradability enhancement.

    Science.gov (United States)

    Suárez-Ojeda, María Eugenia; Kim, Jungkwon; Carrera, Julián; Metcalfe, Ian S; Font, Josep

    2007-06-18

    Wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) were investigated as suitable precursors for the biological treatment of industrial wastewater containing sodium dodecylbenzene sulfonate (DBS). Two hours WAO semi-batch experiments were conducted at 15 bar of oxygen partial pressure (P(O2)) and at 180, 200 and 220 degrees C. It was found that the highest temperature provides appreciable total organic carbon (TOC) and chemical oxygen demand (COD) abatement of about 42 and 47%, correspondingly. Based on the main identified intermediates (acetic acid and sulfobenzoic acid) a reaction pathway for DBS and a kinetic model in WAO were proposed. In the case of CWAO experiments, seventy-two hours tests were done in a fixed bed reactor in continuous trickle flow regime, using a commercial activated carbon (AC) as catalyst. The temperature and P(O2) were 140-160 degrees C and 2-9 bar, respectively. The influence of the operating conditions on the DBS oxidation, the occurrence of oxidative coupling reactions over the AC, and the catalytic activity (in terms of substrate removal) were established. The results show that the AC without any supported active metal behaves bi-functional as adsorbent and catalyst, giving TOC conversions up to 52% at 160 degrees C and 2 bar of P(O2), which were comparable to those obtained in WAO experiments. Respirometric tests were completed before and after CWAO and to the main intermediates identified through the WAO and CWAO oxidation route. Then, the readily biodegradable COD (COD(RB)) of the CWAO and WAO effluents were found. Taking into account these results it was possible to compare whether or not the CWAO or WAO effluents were suitable for a conventional activated sludge plant inoculated with non adapted culture. PMID:17363148

  15. Catalytic and non-catalytic wet air oxidation of sodium dodecylbenzene sulfonate: Kinetics and biodegradability enhancement

    International Nuclear Information System (INIS)

    Wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) were investigated as suitable precursors for the biological treatment of industrial wastewater containing sodium dodecylbenzene sulfonate (DBS). Two hours WAO semi-batch experiments were conducted at 15bar of oxygen partial pressure (PO2) and at 180, 200 and 220deg. C. It was found that the highest temperature provides appreciable total organic carbon (TOC) and chemical oxygen demand (COD) abatement of about 42 and 47%, correspondingly. Based on the main identified intermediates (acetic acid and sulfobenzoic acid) a reaction pathway for DBS and a kinetic model in WAO were proposed. In the case of CWAO experiments, seventy-two hours tests were done in a fixed bed reactor in continuous trickle flow regime, using a commercial activated carbon (AC) as catalyst. The temperature and PO2 were 140-160deg. C and 2-9bar, respectively. The influence of the operating conditions on the DBS oxidation, the occurrence of oxidative coupling reactions over the AC, and the catalytic activity (in terms of substrate removal) were established. The results show that the AC without any supported active metal behaves bi-functional as adsorbent and catalyst, giving TOC conversions up to 52% at 160deg. C and 2 bar of PO2, which were comparable to those obtained in WAO experiments. Respirometric tests were completed before and after CWAO and to the main intermediates identified through the WAO and CWAO oxidation route. Then, the readily biodegradable COD (CODRB) of the CWAO and WAO effluents were found. Taking into account these results it was possible to compare whether or not the CWAO or WAO effluents were suitable for a conventional activated sludge plant inoculated with non adapted culture

  16. Catalytic and non-catalytic wet air oxidation of sodium dodecylbenzene sulfonate: Kinetics and biodegradability enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Suarez-Ojeda, Maria Eugenia [Departament d' Enginyeria Quimica, Escola Tecnica Superior d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paisos Catalans 26, 43007 Tarragona, Catalonia (Spain); Departament d' Enginyeria Quimica, Edifici Q-ETSE, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona, Catalonia (Spain); Kim, Jungkwon [Chemical Engineering and Analytical Sciences Department, University of Manchester, Manchester (United Kingdom); Carrera, Julian [Departament d' Enginyeria Quimica, Edifici Q-ETSE, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona, Catalonia (Spain); Metcalfe, Ian S. [Chemical Engineering and Advanced Materials Department, University of Newcastle upon Tyne, Newcastle upon Tyne (United Kingdom); Font, Josep [Departament d' Enginyeria Quimica, Escola Tecnica Superior d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paisos Catalans 26, 43007 Tarragona, Catalonia (Spain)]. E-mail: jose.font@urv.cat

    2007-06-18

    Wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) were investigated as suitable precursors for the biological treatment of industrial wastewater containing sodium dodecylbenzene sulfonate (DBS). Two hours WAO semi-batch experiments were conducted at 15bar of oxygen partial pressure (P{sub O{sub 2}}) and at 180, 200 and 220deg. C. It was found that the highest temperature provides appreciable total organic carbon (TOC) and chemical oxygen demand (COD) abatement of about 42 and 47%, correspondingly. Based on the main identified intermediates (acetic acid and sulfobenzoic acid) a reaction pathway for DBS and a kinetic model in WAO were proposed. In the case of CWAO experiments, seventy-two hours tests were done in a fixed bed reactor in continuous trickle flow regime, using a commercial activated carbon (AC) as catalyst. The temperature and P{sub O{sub 2}} were 140-160deg. C and 2-9bar, respectively. The influence of the operating conditions on the DBS oxidation, the occurrence of oxidative coupling reactions over the AC, and the catalytic activity (in terms of substrate removal) were established. The results show that the AC without any supported active metal behaves bi-functional as adsorbent and catalyst, giving TOC conversions up to 52% at 160deg. C and 2 bar of P{sub O{sub 2}}, which were comparable to those obtained in WAO experiments. Respirometric tests were completed before and after CWAO and to the main intermediates identified through the WAO and CWAO oxidation route. Then, the readily biodegradable COD (COD{sub RB}) of the CWAO and WAO effluents were found. Taking into account these results it was possible to compare whether or not the CWAO or WAO effluents were suitable for a conventional activated sludge plant inoculated with non adapted culture.

  17. Spin-on metal oxide materials with high etch selectivity and wet strippability

    Science.gov (United States)

    Yao, Huirong; Mullen, Salem; Wolfer, Elizabeth; McKenzie, Douglas; Rahman, Dalil; Cho, JoonYeon; Padmanaban, Munirathna; Petermann, Claire; Hong, SungEun; Her, YoungJun

    2016-03-01

    Metal oxide or metal nitride films are used as hard mask materials in semiconductor industry for patterning purposes due to their excellent etch resistances against the plasma etches. Chemical vapor deposition (CVD) or atomic layer deposition (ALD) techniques are usually used to deposit the metal containing materials on substrates or underlying films, which uses specialized equipment and can lead to high cost-of-ownership and low throughput. We have reported novel spin-on coatings that provide simple and cost effective method to generate metal oxide films possessing good etch selectivity and can be removed by chemical agents. In this paper, new spin-on Al oxide and Zr oxide hard mask formulations are reported. The new metal oxide formulations provide higher metal content compared to previously reported material of specific metal oxides under similar processing conditions. These metal oxide films demonstrate ultra-high etch selectivity and good pattern transfer capability. The cured films can be removed by various chemical agents such as developer, solvents or wet etchants/strippers commonly used in the fab environment. With high metal MHM material as an underlayer, the pattern transfer process is simplified by reducing the number of layers in the stack and the size of the nano structure is minimized by replacement of a thicker film ACL. Therefore, these novel AZ® spinon metal oxide hard mask materials can potentially be used to replace any CVD or ALD metal, metal oxide, metal nitride or spin-on silicon-containing hard mask films in 193 nm or EUV process.

  18. Metabolic Engineering of Saccharomyces cerevisiae for Astaxanthin Production and Oxidative Stress Tolerance▿

    OpenAIRE

    Ukibe, Ken; Hashida, Keisuke; Yoshida, Nobuyuki; Takagi, Hiroshi

    2009-01-01

    The red carotenoid astaxanthin possesses higher antioxidant activity than other carotenoids and has great commercial potential for use in the aquaculture, pharmaceutical, and food industries. In this study, we produced astaxanthin in the budding yeast Saccharomyces cerevisiae by introducing the genes involved in astaxanthin biosynthesis of carotenogenic microorganisms. In particular, expression of genes of the red yeast Xanthophyllomyces dendrorhous encoding phytoene desaturase (crtI product)...

  19. Effect of SUS316L stainless steel surface conditions on the wetting of molten multi-component oxides ceramic

    International Nuclear Information System (INIS)

    Highlights: • Multi-component oxides had a good wetting on stainless substrates with pretreatments. • Various substrates surface roughness caused the difference of final contact angles. • The wetting rate was slow on polished substrate due to the slow surface oxidation. - Abstract: A study on the effect of SUS316L stainless steel surface conditions on the wetting behavior of molten multi-component oxides ceramic was performed and aimed to contribute to the further understanding of the application of oxides ceramic in penetration treatment of stainless steel coatings and the deposition of stainless steel cermet coatings. The results show that at 1273 K, different surface pre-treatments (polishing and heating) had an important effect on the wetting behavior. The molten multi-component oxides showed good wettability on both stainless steel substrates, however, the wetting process on the polished substrate was significantly slower than that on the heated substrates. The mechanism of the interfacial reactions was discussed based on the microscopic and thermodynamic analysis, the substrates reacted with oxygen generated from the decomposition of the molten multi-component oxides and oxygen contained in the argon atmosphere, and the oxide film caused the molten multi-component oxides ceramic to spread on the substrates surfaces. For the polished substrate, more time was required for the surface oxidation to reach the surface composition of Heated-S, which resulted in relatively slow spreading and wetting rates. Moreover, the variance of the surface roughness drove the final contact angles to slightly different values following the sequence Polished-S > Heated-S

  20. Effect of SUS316L stainless steel surface conditions on the wetting of molten multi-component oxides ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jin, E-mail: wangjinustb@gmail.com [Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka, 808-0196 (Japan); Matsuda, Nozomu [Bar and Wire Product Unit, Nippon steel and Sumitomo Metal Corporation, Fukuoka, 802-8686 (Japan); Shinozaki, Nobuya [Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka, 808-0196 (Japan); Miyoshi, Noriko [The Center for Instrumental Analysis, Kyushu Institute of Technology, Fukuoka, 804-8550 (Japan); Shiraishi, Takanobu [Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, 852-8588 (Japan)

    2015-02-01

    Highlights: • Multi-component oxides had a good wetting on stainless substrates with pretreatments. • Various substrates surface roughness caused the difference of final contact angles. • The wetting rate was slow on polished substrate due to the slow surface oxidation. - Abstract: A study on the effect of SUS316L stainless steel surface conditions on the wetting behavior of molten multi-component oxides ceramic was performed and aimed to contribute to the further understanding of the application of oxides ceramic in penetration treatment of stainless steel coatings and the deposition of stainless steel cermet coatings. The results show that at 1273 K, different surface pre-treatments (polishing and heating) had an important effect on the wetting behavior. The molten multi-component oxides showed good wettability on both stainless steel substrates, however, the wetting process on the polished substrate was significantly slower than that on the heated substrates. The mechanism of the interfacial reactions was discussed based on the microscopic and thermodynamic analysis, the substrates reacted with oxygen generated from the decomposition of the molten multi-component oxides and oxygen contained in the argon atmosphere, and the oxide film caused the molten multi-component oxides ceramic to spread on the substrates surfaces. For the polished substrate, more time was required for the surface oxidation to reach the surface composition of Heated-S, which resulted in relatively slow spreading and wetting rates. Moreover, the variance of the surface roughness drove the final contact angles to slightly different values following the sequence Polished-S > Heated-S.

  1. Effects of microcystin-LR on Saccharomyces cerevisiae growth, oxidative stress and apoptosis.

    Science.gov (United States)

    Valério, Elisabete; Vilares, Arminda; Campos, Alexandre; Pereira, Paulo; Vasconcelos, Vitor

    2014-11-01

    Microcystins (MC) are cyanotoxins occurring globally, known for causing acute hepatotoxicity in humans/animals, tumor promotion in animals and potential carcinogenicity. The mechanism of MC toxicity is considered a multi-pathway process involving the inhibition of protein phosphatases PP1/PP2A and the production of reactive oxygen species (ROS). However, their mechanism of action is not fully characterized, thus hampering the complete hazard identification. In this study, we evaluated the effect of several microcystin-LR concentrations on the growth, ROS levels, antioxidant system response and apoptosis induction on Saccharomyces cerevisiae. Our results showed that the growth of S. cerevisiae was not inhibited when compared to control cells. However, the staining of cells with DHR123 and DHE revealed an intracellular increase of the ROS levels. This ROS increase resulted in an augment of catalase activity and inhibition of SOD. All these facts suggest that hydrogen peroxide was the main ROS induced by MCLR. Signs of apoptosis were also detected in the cells exposed to toxin. Our results show that S. cerevisiae VL3 displays MCLR toxicity effects known to occur in higher eukaryotes and confirmed that it can be a simple and good model to help further in the elucidation of MCLR molecular mechanisms of toxicity. PMID:25157802

  2. SPONTANEOUS CATALYTIC WET AIR OXIDATION DURING PRE-TREATMENT OF HIGH-LEVEL RADIOACTIVE WASTE SLUDGE

    Energy Technology Data Exchange (ETDEWEB)

    Koopman, D.; Herman, C.; Pareizs, J.; Bannochie, C.; Best, D.; Bibler, N.; Fellinger, T.

    2009-10-01

    Savannah River Remediation, LLC (SRR) operates the Defense Waste Processing Facility for the U.S. Department of Energy at the Savannah River Site. This facility immobilizes high-level radioactive waste through vitrification following chemical pretreatment. Catalytic destruction of formate and oxalate ions to carbon dioxide has been observed during qualification testing of non-radioactive analog systems. Carbon dioxide production greatly exceeded hydrogen production, indicating the occurrence of a process other than the catalytic decomposition of formic acid. Statistical modeling was used to relate the new reaction chemistry to partial catalytic wet air oxidation of both formate and oxalate ions driven by the low concentrations of palladium, rhodium, and/or ruthenium in the waste. Variations in process conditions led to increases or decreases in the total oxidative destruction, as well as partially shifting the preferred species undergoing destruction from oxalate ion to formate ion.

  3. Treatment of toxic and hazardous organic wastes by wet oxidation process with oxygenated water at low temperature

    International Nuclear Information System (INIS)

    The wet oxidation process using air or molecular oxygen is a well-known process from long time. It is suitable to oxidize several types of waste refractory to the usual biological, thermal and chemical treatments. The drastic operating conditions (high pressures and temperatures) prevented its industrial development. In the last years a new interest was assigned to the process for the treatment of nuclear wastes (organic resins and exhaust organic wastes); the treatment is carried out at widely reduced operating conditions (atmospheric pressure and boiling temperature) by means of metallic catalysts and hydrogen peroxide. With some limits, the wet oxidation with hydrogen peroxide at low temperature can be applied to conventional waste waters containing toxic organic compounds. In the present report are summarized the activities developed at ENEA Fuel Cycle Department by the task force 'Deox' constituted by laboratory and plant specialists in order to verify the application of the wet oxidation process to the treatment of the toxic wastes. (author)

  4. Catalytic wet air oxidation of 2-chlorophenol over sewage sludge-derived carbon-based catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Yuting [Institut de recherches sur la catalyse et l’environnement de Lyon (IRCELYON), CNRS – Université Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France); School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Xiong, Ya; Tian, Shuanghong [School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275 (China); Kong, Lingjun [School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Descorme, Claude, E-mail: claude.descorme@ircelyon.univ-lyon1.fr [Institut de recherches sur la catalyse et l’environnement de Lyon (IRCELYON), CNRS – Université Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France)

    2014-07-15

    Highlights: • A sewage sludge derived carbon-supported iron oxide catalyst (FeSC) was prepared. • FeSC exhibited high catalytic activity in the wet air oxidation of 2-chlorophenol. • A strong correlation was observed between the 2-CP conversion, the iron leaching and the pH. • Using an acetate buffer, the iron leaching was suppressed while keeping some catalytic activity. • A simplified reaction pathway was proposed for the CWAO of 2-CP over the FeSC catalyst. - Abstract: A sewage sludge derived carbon-supported iron oxide catalyst (FeSC) was prepared and used in the Catalytic Wet Air Oxidation (CWAO) of 2-chlorophenol (2-CP). The catalysts were characterized in terms of elemental composition, surface area, pH{sub PZC}, XRD and SEM. The performances of the FeSC catalyst in the CWAO of 2-CP was assessed in a batch reactor operated at 120 °C under 0.9 MPa oxygen partial pressure. Complete decomposition of 2-CP was achieved within 5 h and 90% Total Organic Carbon (TOC) was removed after 24 h of reaction. Quite a straight correlation was observed between the 2-CP conversion, the amount of iron leached in solution and the pH of the reaction mixture at a given reaction time, indicating a strong predominance of the homogeneous catalysis contribution. The iron leaching could be efficiently prevented when the pH of the solution was maintained at values higher than 4.5, while the catalytic activity was only slightly reduced. Upon four successive batch CWAO experiments, using the same FeSC catalyst recovered by filtration after pH adjustment, only a very minor catalyst deactivation was observed. Finally, based on all the identified intermediates, a simplified reaction pathway was proposed for the CWAO of 2-CP over the FeSC catalyst.

  5. Catalytic wet air oxidation of 2-chlorophenol over sewage sludge-derived carbon-based catalysts

    International Nuclear Information System (INIS)

    Highlights: • A sewage sludge derived carbon-supported iron oxide catalyst (FeSC) was prepared. • FeSC exhibited high catalytic activity in the wet air oxidation of 2-chlorophenol. • A strong correlation was observed between the 2-CP conversion, the iron leaching and the pH. • Using an acetate buffer, the iron leaching was suppressed while keeping some catalytic activity. • A simplified reaction pathway was proposed for the CWAO of 2-CP over the FeSC catalyst. - Abstract: A sewage sludge derived carbon-supported iron oxide catalyst (FeSC) was prepared and used in the Catalytic Wet Air Oxidation (CWAO) of 2-chlorophenol (2-CP). The catalysts were characterized in terms of elemental composition, surface area, pHPZC, XRD and SEM. The performances of the FeSC catalyst in the CWAO of 2-CP was assessed in a batch reactor operated at 120 °C under 0.9 MPa oxygen partial pressure. Complete decomposition of 2-CP was achieved within 5 h and 90% Total Organic Carbon (TOC) was removed after 24 h of reaction. Quite a straight correlation was observed between the 2-CP conversion, the amount of iron leached in solution and the pH of the reaction mixture at a given reaction time, indicating a strong predominance of the homogeneous catalysis contribution. The iron leaching could be efficiently prevented when the pH of the solution was maintained at values higher than 4.5, while the catalytic activity was only slightly reduced. Upon four successive batch CWAO experiments, using the same FeSC catalyst recovered by filtration after pH adjustment, only a very minor catalyst deactivation was observed. Finally, based on all the identified intermediates, a simplified reaction pathway was proposed for the CWAO of 2-CP over the FeSC catalyst

  6. Green chemicals from pulp production black liquor by partial wet oxidation.

    Science.gov (United States)

    Muddassar, Hassan Raja; Melin, Kristian; de Villalba Kokkonen, Daniela; Riera, Gerard Viader; Golam, Sarwar; Koskinen, Jukka

    2015-11-01

    To reduce greenhouse gas emissions, more sustainable sources of energy, fuel and chemicals are needed. Biomass side streams such as black liquor, which is a by-product of pulp production, has the potential to be used for this purpose. The aim of the study was the production of carboxylic acids, such as lactic acid, formic acid and acetic acid, from kraft and non-wood black liquor. The processes studied were partial wet oxidation (PWO) and catalytic partial wet oxidation (CPWO). The results show that the yield of carboxylic acid is higher when treated by PWO than the results from CPWO at temperatures of 170 °C and 230 °C. The results shows that the PWO process can increase the yield of carboxylic acids and hydroxy acids in black liquor, reduce lignin content and decrease pH, which makes further separation of the acids more favourable. The hydroxy acids are valuable raw materials for biopolymers, and acetic acid and formic acid are commonly used chemicals conventionally produced from fossil feedstock. PMID:26377325

  7. Biodegradability enhancement by wet oxidation in alkaline media: delignification as a case study.

    Science.gov (United States)

    Verenich, S; Kallas, J

    2002-06-01

    Nowadays many industries are considering the recycling of process waters as a way of improving environmental safety, preventing pollution, and avoiding the loss of valuable production materials. One industry in the forefront of this trend is the pulp and paper industry. Lignin is a pollutant present in the mill process waters and such macromolecules can cause problems during biological treatment of process waters. Wet oxidation (WO) is a process that can be used as a pre-treatment method for lignin fragmentation and improvement of biodegradability. Wet oxidation (WO) under alkaline conditions permits faster lignin fragmentation than the conventional WO process and, therefore, should favour biodegradability improvement. In this study, the experiments were carried out in a high-pressure batch reactor with an alkali lignin solution at temperatures up to 438 K, an alkali concentration of 1.5-3.5 g l(-1) and an oxygen partial pressure of 0.4 to 1.5 MPa. At an alkali concentration of 3.5 g l(-1)1 and 0.4 MPa of oxygen partial pressure, an increase in BOD/COD ratio was achieved from an initial 11% to 71%. The experiments also showed that the amount of small molecules in the solution measured by Immediately Available BOD (IA BOD) depends on the amount of alkali added and the operating temperature. PMID:12118617

  8. Treatment of desizing wastewater from the textile industry by wet air oxidation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper describes the application of wet air oxidation to the treatment of desizing wastewater from two textile companies. A two-liter high temperature, high pressure autoclave reactor was used in the study. The range of operating temperatures examined was between 150 and 290℃, and the partial pressure of oxygen ranged from 0. 375 to 2.25 MPa. Variations in pH,CODCr and TOD content were monitored during each experiment and used to assess the extent of conversion of the process. The effects of temperature, pressure and reaction time were explored extensively. More than 90 % CODCr reduction and 80 % TOC removal have been obtained. The results have also been demonstrated that WAO is a suitable pre-treatment methods due to improvement of the BOD5/CODCr ratio of desizing wastewater. The reaction kinetics of wet air oxidation of desizing wastewater has been proved to be two steps, a fast reaction followed by a slow reaction stage.

  9. Kinetics of Wet Air Oxidation of Wastewater from Natural Fiber Web Desizing

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This work described the application of wet air oxidation (WAO) to the treatment of desizing wastewater from natural fiber processing. A two-liter autoclave batch reactor was used for the experiments. The range of operating temperature examined was between 150 and 290℃, and partial pressure of oxygen ranged from 0.375 to 2.25 MPa standardized at 25℃. Variations in Chemical Oxygen Demand(COD) and Total Organic Carbon(TOC) were monitored during each experiment and used to assess the performance of the process. Experimental results showed that WAO can be an efficient method for the treatment of desizing wnstewater. Furthermore, Catalytic Wet Air Oxidation (CWAO) was applied to reduce the reaction temperature and pressure in WAO process. A higher COD removal ratio was achieved under more mild reaction condition with the aid of CWAO. A mathematical model was also proposed to simulate the WAO process of desizing wastewater, in which three distinct kinetics steps were considered to describe the degradation of starch. The model simulations were in well agreement with the experimental data.

  10. Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Bojsen, Rasmus K; Andersen, Kaj Scherz; Regenberg, Birgitte

    2012-01-01

    Microbial biofilms can be defined as multi-cellular aggregates adhering to a surface and embedded in an extracellular matrix (ECM). The nonpathogenic yeast, Saccharomyces cerevisiae, follows the common traits of microbial biofilms with cell-cell and cell-surface adhesion. S. cerevisiae is shown t...... cues, cell-to-cell variation and niches in S. cerevisiae biofilm. Being closely related to Candida species, S. cerevisiae is a model to investigate biofilms of pathogenic yeast....

  11. Effect of nitrogen doping on wetting and photoactive properties of laser processed zinc oxide-graphene oxide nanocomposite layers

    Energy Technology Data Exchange (ETDEWEB)

    György, E., E-mail: egyorgy@icmab.es [Consejo Superior de Investigaciones Cientificas, Instituto de Ciencia de Materiales de Barcelona (CSIC-ICMAB), Campus UAB, 08193 Bellaterra (Spain); National Institute for Lasers, Plasma and Radiation Physics, P. O. Box MG 36, 76900 Bucharest V (Romania); Pérez del Pino, A. [Consejo Superior de Investigaciones Cientificas, Instituto de Ciencia de Materiales de Barcelona (CSIC-ICMAB), Campus UAB, 08193 Bellaterra (Spain); Logofatu, C. [National Institute for Materials Physics, P. O. Box MG. 7, 77125 Bucharest (Romania); Duta, A.; Isac, L. [Transilvania University of Brasov, Research Centre for Renewable Energy Systems and Recycling, Eroilor 29, 500036, Brasov (Romania)

    2014-07-14

    Zinc oxide-graphene oxide nanocomposite layers were submitted to laser irradiation in air or controlled nitrogen atmosphere using a frequency quadrupled Nd:YAG (λ = 266 nm, τ{sub FWHM} ≅ 3 ns, ν = 10 Hz) laser source. The experiments were performed in air at atmospheric pressure or in nitrogen at a pressure of 2 × 10{sup 4} Pa. The effect of the irradiation conditions, incident laser fluence value, and number of subsequent laser pulses on the surface morphology of the composite material was systematically investigated. The obtained results reveal that nitrogen incorporation improves significantly the wetting and photoactive properties of the laser processed layers. The kinetics of water contact angle variation when the samples are submitted to laser irradiation in nitrogen are faster than that of the samples irradiated in air, the surfaces becoming super-hydrophilic under UV light irradiation.

  12. On ultra-thin oxide/Si and very-thin oxide/Si structures prepared by wet chemical process

    International Nuclear Information System (INIS)

    The properties of ultra-thin oxide/Si and very-thin oxide/Si structures prepared by wet chemical oxidation in nitric acid aqueous solutions (NAOS) and passivated in HCN aqueous solutions were investigated by electrical, optical and structural methods. n- and p-doped (1 0 0) crystalline Si substrates were used. There were identified more types of interface defect states in dependence on both post-oxidation treatment and passivation procedure. On samples prepared on n-type Si, continuous spectrum of defect states of 0.05-0.2 eV range and discrete defect traps, ∼ECB - 0.26 eV and ∼ECB - 0.39 eV, were found. All mentioned defects are related with various types of Si dangling bonds and/or with SiOx precipitates. Post-metallization annealing of investigated MOS structures reduced the interface defect density and suppressed the leakage currents. It did not change spectral profile of interface defect states in the Si band gap. In addition, there are presented following two optical phenomena: relation between amplitude of photoluminescence signal of NAOS samples and parameters of chemical oxidation process and quantum confinement effect observed on samples containing Si grains of size less as ∼2 nm.

  13. Oxidation of a novel CeO{sub 2}-dispersed chromium coating in wet air

    Energy Technology Data Exchange (ETDEWEB)

    Peng, X.; Yan, J.; Zheng, L.; Wang, F. [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2011-06-15

    An electrodeposited Ni-CeO{sub 2} composite was used as a ''precursor film'' for a novel CeO{sub 2}-dispersed chromium coating deposited using a traditional pack cementation method. The substrate was a carbon steel. For comparison, chromium coatings were also prepared on the untreated and pure Ni-film-treated carbon steel using the same pack cementation conditions. Oxidation in 5% O{sub 2} + 40% H{sub 2}O + N{sub 2} at 900 C showed that, compared to the CeO{sub 2}-free coating counterparts, the CeO{sub 2}-dispersed chromium coating exhibited greatly increased oxidation resistance, owing to the development of a denser and more slowly growing chromia scale. The slow growth of the scale was correlated with the CeO{sub 2} dispersion exerting the so-called ''reactive elemental effect (REE)'' on oxidation. The oxidation mechanisms in wet air of the various types of coatings were compared to those in dry air and are fully discussed in this work. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Influencia de la Peroxidación de Lípidos sobre el Daño Oxidativo Mitocondrial y la Integridad de Saccharomyces cerevisiae Influence of Lipoperoxidation over Mitochondrial Oxidative Damage and Integrity of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Christian Cortés-Rojo

    2009-01-01

    Full Text Available Se ha estudiado la influencia de la peroxidación de lípidos sobre el daño oxidativo mitocondrial y la integridad de Saccharomyces cerevisiae. Para esto, se aumentó el grado de insaturación de las membranas celulares de S. cerevisiae con ácido α-linolénico (C18:3. Se obtuvieron esferoplastos para poder estudiar la función mitocondrial in situ. Se encontró que la peroxidación de lípidos, estimulada por la adición de Fe2+, incrementó únicamente en esferoplastos con C18:3, mientras que la función mitocondrial, medida como el consumo de oxígeno sensible a cianuro y la integridad celular, determinada por la exclusión del colorante azul de tripano, se ven afectadas de manera significativa sólo en esferoplastos con C18:3. Estos resultados muestran que la peroxidación de lípidos sensibiliza la integridad celular y la función mitocondrial hacia los daños por el estrés oxidativo.The influence of lipoperoxidation over mitochondrial oxidative damage and integrity of Saccharomyces cerevisiae has been studied. For this, the unsaturation degree of cell membranes from Saccharomyces cerevisiae was increased by adding α-linolenic acid (C18:3. Spheroplasts were obtained to evaluate in situ the mitochondrial function. Lipid peroxidation levels, stimulated by the treatment with Fe2+, increased only in spheroplasts with C18:3, while mitochondrial function, measured as cyanide-sensitive oxygen consumption, and cell integrity, determined by trypan blue exclusion, were affected significatively only in spheroplasts with C18:3. These results show that lipid peroxidation sensitizes cell integrity and mitochondrial function towards damaging effects of oxidative stress.

  15. Inhibition and deactivation effects in catalytic wet oxidation of high-strength alcohol-distillery liquors

    Energy Technology Data Exchange (ETDEWEB)

    Belkacemi, K.; Larachi, F.; Hamoudi, S.; Turcotte, G.; Sayari, A. [Laval Univ., Sainte-Foy, Quebec (Canada)

    1999-06-01

    The removal efficiency of total organic carbon (TOC) from raw high-strength alcohol-distillery waste liquors was evaluated using three different treatments: thermolysis (T), noncatalytic wet oxidation (WO), and solid-catalyzed wet oxidation (CWO). The distillery liquors (TOC = 22,500 mg/l, sugars = 18,000 mg/l, and proteins = 13,500 mg/l) were produced by alcoholic fermentation of enzymatic hydrolyzates from steam-exploded timothy grass. TOC-abatement studies were conducted batchwise in a stirred autoclave to evaluate the influence of the catalyst (7:3, MnO{sub 2}/CeO{sub 2} mixed oxide), oxygen partial pressure (0.5--2.5 MPa), and temperature (453--523 K) on T, WO, and CWO processes. Although CWO outperformed T and WO, TOC conversions did not exceed {approximately}60% at the highest temperature used. Experiments provided prima facie evidence for a gradual fouling of the catalyst and a developing inhibition in the liquors which impaired deep TOC removals. Occurrence of catalyst deactivation by carbonaceous deposits was proven experimentally through quantitative and qualitative experiments such as elemental analysis and X-ray photoelectron spectroscopy. Inhibition toward further degradation of the liquors was ascribed to the occurrence of highly stable antioxidant intermediates via the Maillard reactions between dissolved sugars and proteins. A lumping kinetic model involving both reaction inhibition by dissolved intermediates and catalyst deactivation by carbonaceous deposits was proposed to account for the distribution of carbon in the liquid, solid, and the vapor phases.

  16. Conversion of the refractory ammonia and acetic acid in catalytic wet air oxidation of animal byproducts

    Institute of Scientific and Technical Information of China (English)

    Virginie Fontanier; Sofiane Zalouk; Stéphane Barbati

    2011-01-01

    Wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) of slaughtered animal byproducts (ABPs) were investigated.Two step experiment was carried out consisting ofa non-catalysed WAO run followed by a CWAO run at 170-275℃, 20 MPa, and reaction time 180 min.The WAO (1st step) of sample (5 g/L total organic carbon (TOC)) yielded (82.0 ± 4)% TOC removal and (78.4 ± 13.2)%conversion of the initial organic-N into NH4+-N.Four metal catalysts (Pd, Pt, Rh, Ru) supported over alumina have been tested in catalytic WAO (2nd step) at elevated pH to enhance ammonia conversion and organic matter removal, particularly acetic acid.It was found that the catalysts Ru, Pt, and Rh had significant effects on the TOC removal (95.1%, 99.5% and 96.7%, respectively) and on the abatement of ammonia (93.4%, 96.7% and 96.3%, respectively) with high nitrogen selectivity.The catalyst Pd was found to have the less activity while Pt had the best performance.The X-Ray diffraction analysis showed that the support of catalyst was not stable under the experimental conditions since it reacted with phosphate present in solution.Nitrite and nitrate ions were monitored during the oxidation reaction and it was concluded that CWAO of ammonia in real waste treatment framework was in good agreement with the results obtained from the literature for ideal solutions of ammonia.

  17. Comparison of the chemical properties of wheat straw and beech fibers following alkaline wet oxidation and laccase treatments

    DEFF Research Database (Denmark)

    Schmidt, A. S.; Mallon, S.; Thomsen, Anne Belinda;

    2002-01-01

    Wheat straw (Triticum aestivum) and beech (Fagus sylvatica), were used to evaluate the effects of two pre-treatment processes (alkaline wet oxidation and enzyme treatment with laccase) on lignocellulosic materials for applications in particleboards and fiberboards. Wheat straw and beech fibers...... reacted differently in the two processes. The chemical composition changed little following enzyme treatment. After alkaline wet oxidation, fibers enriched in cellulose were obtained. With both materials, almost all hemicellulose (80%) together with a large portion of the lignin were solubilised by...... alkaline wet oxidation, but essentially all cellulose remained in the solid fraction. Following enzyme treatment most material remained as a solid. For wheat straw, reaction with acetic anhydride indicated that both treatments resulted in more hydroxyl groups being accessible for reaction. The enzyme...

  18. Development of chemical and biological processes for production of bioethanol. Optimization of the wet oxidation process and characterization of products

    International Nuclear Information System (INIS)

    The combination of the wet oxidation pretreatment process and alkaline hydrolysis was investigated in order to efficiently solubilize the hemicellulose, degrade the lignin, and open the solid crystalline cellulose structure of wheat straw lignocellulose without generating fermentation inhibitors. The effects of temperature, oxygen pressure, reaction time, and concentration of straw were evaluated. The degree of lignin degradation and hemicellulose solubilization increased with the reaction temperature and time. The optimum conditions were 15 minutes at 185 deg. C, producing 9.8 g/L hemicellulose. For quantification of the solubilized hemicellulose the best overall acid hydrolysis was obtained by treatment with 4 %w/v sulfuric acid for 10 minutes. The Aminex HPX-87H column was less sensitive towards impurities than the Aminex HPX-87P column. HPX-87H gave improved recovery and reproducibility, and was chosen for routine quantification of hydrolyzed hemicellulose sugars. The purity of the solid cellulose fraction also improved with higher temperature. The optimum condition for obtaining enzymatic convertible cellulose (90%) was 10 minutes at 170 deg. C using a high carbonate concentration. The hemicellulose yield and recovery were significantly reduced under these conditions indicating that a simultaneous optimal utilization of the hemicellulose and cellulose was difficult. The oxygen pressure and sodium carbonate concentration had little effect on the solubilization of hemicellulose, however, by combining wet oxidation with alkaline hydrolysis the formation of 2-furfural, a known microbial inhibitor, was minimal. Much more hemicellulose and lignin were solubilized from the straw by wet oxidation than by steaming(an alternative process). More cellulose was solubilized (and degraded) by steaming than by wet oxidation. Overall carbohydrates 'losses' of 20.1% for steaming and 16.2% for wet oxidation were found. More 2-furfural was formed by steaming than by wet oxidation

  19. Development of chemical and biological processes for production of bioethanol. Optimization of the wet oxidation process and characterization of products

    Energy Technology Data Exchange (ETDEWEB)

    Bjerre, A.B.; Skammelsen Schmidt, A.

    1997-02-01

    The combination of the wet oxidation pretreatment process and alkaline hydrolysis was investigated in order to efficiently solubilize the hemicellulose, degrade the lignin, and open the solid crystalline cellulose structure of wheat straw lignocellulose without generating fermentation inhibitors. The effects of temperature, oxygen pressure, reaction time, and concentration of straw were evaluated. The degree of lignin degradation and hemicellulose solubilization increased with the reaction temperature and time. The optimum conditions were 15 minutes at 185 deg. C, producing 9.8 g/L hemicellulose. For quantification of the solubilized hemicellulose the best overall acid hydrolysis was obtained by treatment with 4 %w/v sulfuric acid for 10 minutes. The Aminex HPX-87H column was less sensitive towards impurities than the Aminex HPX-87P column. HPX-87H gave improved recovery and reproducibility, and was chosen for routine quantification of hydrolyzed hemicellulose sugars. The purity of the solid cellulose fraction also improved with higher temperature. The optimum condition for obtaining enzymatic convertible cellulose (90%) was 10 minutes at 170 deg. C using a high carbonate concentration. The hemicellulose yield and recovery were significantly reduced under these conditions indicating that a simultaneous optimal utilization of the hemicellulose and cellulose was difficult. The oxygen pressure and sodium carbonate concentration had little effect on the solubilization of hemicellulose, however, by combining wet oxidation with alkaline hydrolysis the formation of 2-furfural, a known microbial inhibitor, was minimal. Much more hemicellulose and lignin were solubilized from the straw by wet oxidation than by steaming(an alternative process). More cellulose was solubilized (and degraded) by steaming than by wet oxidation. Overall carbohydrates `losses` of 20.1% for steaming and 16.2% for wet oxidation were found. More 2-furfural was formed by steaming than by wet oxidation.

  20. Volume reduction of lake sediment and decrease of its cesium content in decontamination process by wet oxidation method

    International Nuclear Information System (INIS)

    Wet oxidation method was applied aiming to decrease cesium contents in lake sediment. In this research, “reactive oxygen water”, that is prepared from hypochlorous acid by contact with metal ceramics, was reacted with three kinds of samples, that is, lake sediment, mixture of lake sediment and fallen leaves, and incineration ash of fallen leaves. Experimental results revealed that sample volume was reduced by means of wet oxidation of organic components in samples and that a large amount of cesium contents were transferred from sample to water phase. (author)

  1. Subcritical wet oxidation of municipal sewage sludge: comparison of batch and continuous experiments.

    Science.gov (United States)

    Lendormi, T; Prevot, C; Doppenbe, F; Foussard, J N; Debellefontaine, H

    2001-01-01

    Wet oxidation in subcritical conditions is a new alternative to usual routes for sewage sludge treatment and it complies with environmental standards. The paper presents tests carried out on a batch reactor and on a continuous pilot unit, treating municipal sewage sludge. A method is proposed that shows that the oxidation efficiency in a continuous reactor can only be easily predicted from the residence time distribution and batch tests results. Nevertheless, a partial settling of the solid residue in the continuous bubble column reactor is evident, and it increases the solid residence time and then decreases its organic content with respect to a similar batch test. In addition, these results highlight the considerable influence of temperature in the oxidation reactor and of the type of sewage sludge which is treated. At temperatures around 240 degrees C, foaming can seriously impair the operation of the continuous reactor, because of the presence of non-degraded fatty compounds and surfactants. Moreover, the COD reduction is limited to 70%. On the contrary, at 300 degrees C, COD removal efficiency greater than 80% is achieved without any catalyst additive and, in addition, only highly biodegradable compounds remain in the oxidised liquor. PMID:11695455

  2. Manganese zinc ferrite nanoparticles as efficient catalysts for wet peroxide oxidation of organic aqueous wastes

    Indian Academy of Sciences (India)

    Manju Kurian; Divya S Nair

    2015-03-01

    Manganese substituted zinc nanoparticles, MnxZn1−xFe2O4 (x = 0.0, 0.25, 0.5, 0.75, 1.0) prepared by sol gel method were found to be efficient catalysts for wet peroxide oxidation of 4-chlorophenol. Complete degradation of the target pollutant occurred within 90 min at 70°C. Zinc substitution enhanced the catalytic efficiency and the unsubstituted ZnFe2O4 oxidized the target compound completely within 45 min. Studies on the effect of reaction variables revealed that only a small amount of the oxidant, H2O2 (3–4 mL) is required for complete degradation of 4-chlorophenol. More than 80% of 4-chlorophenol was removed at catalyst concentrations of 100 mg/L. Direct correlation between the amount of catalyst present and the extent of degradation of 4-chlorophenol was observed, ruling out hesterogeneous-homogeneous mechanism. The catalysts are reusable and complete degradation of target pollutant occurred after five successive runs. The extent of iron leaching was fairly low after five consecutive cycles indicating the mechanism to be heterogeneous.

  3. Fe salts as catalyst for the wet oxidation of o-chlorophenol

    Institute of Scientific and Technical Information of China (English)

    XU Xin-hua; HE Ping; JIN Jian; HAO Zhi-wei

    2005-01-01

    Catalytic wet air oxidation (CWAO) of o-chlorophenol in wastewater was studied in a stainless steel autoclave using four different Fe catalysts in the temperature range of 100-200 ℃. Experimental results showed that high rate of o-chlorophenol and CODcr (Chemical Oxygen Demand, mg/L) removal by CWAO was obtained at relatively low temperature and pressure. The catalysts Fe2(SO4)3, FeSO4, Fe2O3 and FeCl3 all exhibited high catalytic activity. More than 93.7% of the initial CODCr and nearly100% of o-chlorophenol were removed at 150 ℃ after 150 min with FeSO4 as catalyst. The CWAO of o-chlorophenol was found to be pseudo-first order reaction with respect to o-chlorophenol, with activation energy of 75.56 k J/mol in the temperature range of100-175 ℃.

  4. High solid simultaneous saccharification and fermentation of wet oxidized corn stover to ethanol

    DEFF Research Database (Denmark)

    Varga, E.; Klinke, H.B.; Reczey, K.;

    2004-01-01

    In this study ethanol was produced from corn stover pretreated by alkaline and acidic wet oxidation (WO) (195 degreesC, 15 min, 12 bar oxygen) followed by nonisothermal simultaneous saccharification and fermentation (SSF). In the first step of the SSF, small amounts of cellulases were added at 50....../L) were present in the hemicellulose rich hydrolyzate at subinhibitory levels, thus no detoxification was needed prior to SSF of the whole slurry. Based on the cellulose available in the WO corn stover 83% of the theoretical ethanol yield was obtained under optimized SSF conditions. This was achieved with...... a substrate concentration of 12% dry matter (DM) acidic WO corn stover at 30 FPU/g DM (43.5 FPU/g cellulose) enzyme loading. Even with 20 and 15 FPU/g DM (corresponding to 29 and 22 FPU/g cellulose) enzyme loading, ethanol yields of 76 and 73%, respectively, were obtained. After 120 h of SSF the...

  5. Detox{sup SM} wet oxidation system studies for engineering scale up

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, D.T.; Moslander, J.E.; Zigmond, J.A. [Delphi Research, Inc., Albuquerque, NM (United States)] [and others

    1995-12-31

    Catalyzed wet oxidation utilizing iron(III) has been shown to have promise for treating many hazardous and mixed wastes. The reaction occurs at the surface of contact between an aqueous iron(III) solution and organic material. Studies with liquid- and vapor-phase organic waste surrogates have established reaction kinetics and the limits of reaction rate based on organic concentration and iron(III) diffusion. Continuing engineering studies have concentrated on reaction vessel agitator and solids feed configurations, an improved bench scale reflux condenser and reflux condenser calculations, sparging of organic compounds from the process condensate water, filtration of solids from the process solution, and flammability limits for volatile organic compounds in the headspace of the reaction vessel under the reaction conditions. Detailed engineering design and fabrication of a demonstration unit for treatment of mixed waste is in progress.

  6. Study on Catalytic Wet Oxidation of H2S into Sulfur on Fe/Cu Catalyst

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A wet catalytic oxidation at room temperature was investigated with solution containing ferric, ferrous and cupric ions for H2S removal. The experiments were carried out in a two step process,and the results obtained show that the removal efficiency of H2S can always reach 100% in a 300 mm scrubbing column with four sieve plates, and the regeneration of ferric ions in 200 mm bubble column can match the consumed ferric species in absorption. Removal of H2S, production of elemental sulfur and regeneration of ferric, cupric ions can all be accomplished at the same time. No raw material is consumed except O2 in flue gas or air, the process has no secondary pollution and no problem of catalyst degradation and congestion.

  7. Enhancing denitrification using a carbon supplement generated from the wet oxidation of waste activated sludge.

    Science.gov (United States)

    Strong, P J; McDonald, B; Gapes, D J

    2011-05-01

    This study compared the effect of four pure carbon supplements on biological denitrification to a liquor derived as a by-product from the wet oxidation (WO) of waste activated sludge. Sequencing batch reactors were used to acclimate sludge biomass, which was used in batch assays. Acetate, WO liquor and ethanol-supplementation generated the fastest denitrification rates. Acetate and WO liquor were efficiently utilised by all acclimated biomass types, while poor rates were achieved with methanol and formate. When comparing an inoculum from an ethanol-supplemented and non-supplemented wastewater treatment plant (WWTP), the ethanol-acclimated sludge obtained superior denitrification rates when supplemented with ethanol. Similarly high nitrate removal rates were achieved with both sludge types with acetate and WO liquor supplementation, indicating that WO liquors could achieve excellent rates of nitrate removal. The performance of the WO liquor was attributed to the variety of organic carbon substrates (particularly acetic acid) present within the liquor. PMID:21196117

  8. A study on wet catalysis oxidation of spent radioactive ion-exchange resin by hydrogen peroxide

    International Nuclear Information System (INIS)

    Spent radioactive ion-exchange resin (IER) is one of the main kinds of wastes produced by nuclear installations. The authors describe the study on decomposition behaviors of cationic, anionic and mixed IER in H2O2-Ni2+/Cu2+, H2O2-Mn2+/Cu2+, H2O2-Fe2+/Cu2+ and H2O2-Cu2+ systems, analyzes the effects on reaction process and consequence of many factors such as amount of H2O2, catalyst, temperature, pH-value, NaOH and so on. The relation between cementation process and the amount of decomposition residuals was studied. It provided the possible maximum COD-value under which the solidification process would not be affected. The reaction mechanism of the wet chemical oxidation of IER was discussed preliminarily

  9. Optimizing Oily Wastewater Treatment Via Wet Peroxide Oxidation Using Response Surface Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Jianzhong; Wang, Xiuqing; Wang, Xiaoyin [Wuhan Textile Univ., Wuhan (China)

    2014-02-15

    The process of petroleum involves in a large amount of oily wastewater that contains high levels of chemical oxygen demand (COD) and toxic compounds. So they must be treated before their discharge into the receptor medium. In this paper, wet peroxide oxidation (WPO) was adopted to treat the oily wastewater. Central composite design, an experimental design for response surface methodology (RSM), was used to create a set of 31 experimental runs needed for optimizing of the operating conditions. Quadratic regression models with estimated coefficients were developed to describe the COD removals. The experimental results show that WPO could effectively reduce COD by 96.8% at the optimum conditions of temperature 290 .deg. C, H{sub 2}O{sub 2} excess (HE) 0.8, the initial concentration of oily wastewater 3855 mg/L and reaction time 9 min. RSM could be effectively adopted to optimize the operating multifactors in complex WPO process.

  10. Optimizing Oily Wastewater Treatment Via Wet Peroxide Oxidation Using Response Surface Methodology

    International Nuclear Information System (INIS)

    The process of petroleum involves in a large amount of oily wastewater that contains high levels of chemical oxygen demand (COD) and toxic compounds. So they must be treated before their discharge into the receptor medium. In this paper, wet peroxide oxidation (WPO) was adopted to treat the oily wastewater. Central composite design, an experimental design for response surface methodology (RSM), was used to create a set of 31 experimental runs needed for optimizing of the operating conditions. Quadratic regression models with estimated coefficients were developed to describe the COD removals. The experimental results show that WPO could effectively reduce COD by 96.8% at the optimum conditions of temperature 290 .deg. C, H2O2 excess (HE) 0.8, the initial concentration of oily wastewater 3855 mg/L and reaction time 9 min. RSM could be effectively adopted to optimize the operating multifactors in complex WPO process

  11. Analytical aspects of the remediation of soil by wet oxidation - Characterisation of tar contaminants and their degradation products

    DEFF Research Database (Denmark)

    Thomsen, A.B.; Nielsen, T.; Plöger, A.;

    1999-01-01

    Wet oxidation of tar compounds gives rise to a wide range of products. Due to the incorporation of oxygen, these products become increasingly more water soluble and the analytical strategy has to take into account the different physical/chemicalproperties of the compounds. An interplay between gas...

  12. Potential inhibitors from wet oxidation of wheat straw and their effect on growth and ethanol production by Thermoanaerobacter mathranii

    DEFF Research Database (Denmark)

    Klinke, Helene Bendstrup; Thomsen, A.B.; Ahring, Birgitte Kiær

    2001-01-01

    Alkaline wet oxidation (WO) (using water, 6.5 g/l sodium carbonate, and 12 bar oxygen at 195 degreesC) was used for pre-treating wheat straw (60 g/l), resulting in a hemicellulose-rich hydrolysate and a cellulose-rich solid fraction. The hydrolysate consisted of soluble hemicellulose (9 g/l), ali...

  13. Wet oxidation treatment of organic household waste enriched with wheat straw for simultaneous saccharification and fermentation into ethanol

    DEFF Research Database (Denmark)

    Lissens, G.; Klinke, H.B.; Verstraete, W.;

    2004-01-01

    Organic municipal solid waste enriched with wheat straw was subjected to wet-oxidation as a pre-treatment for subsequent enzymatic conversion and fermentation into bio-ethanol. The effect of tempera (185-195degrees C), oxygen pressure (3-12) and sodium carbonate (0-2 g l(-1)) addition on enzymati...

  14. Wet oxidation pre-treatment of woody yard waste: Parameter optimization and enzymatic digestibility for ethanol production

    DEFF Research Database (Denmark)

    Lissens, G.; Klinke, H.B.; Verstraete, W.;

    2004-01-01

    Woody yard waste with high lignin content (22% of dry matter (DM)) was subjected to wet oxidation pre-treatment for subsequent enzymatic conversion and fermentation. The effects of temperature (185-200 degreesC), oxygen pressure (3-12 bar) and addition of sodium carbonate (0-3.3 g per 100 g DM bi...

  15. Wet oxidation of domestic sludge and process integration: the Mineralis process.

    Science.gov (United States)

    Lendormi, T; Prévot, C; Doppenberg, F; Spérandio, M; Debellefontaine, H

    2001-01-01

    Wet oxidation (WO) in subcritical conditions is a new alternative to usual routes for sewage sludge treatment that complies with environmental standards. This paper presents tests carried out using a batch reactor and continuous pilot and industrial units, treating municipal sewage sludge. The main products after oxidation are CO2, water, VFA and ammonia. The results highlight the considerable influence of the treatment temperature and of the type of sewage sludge which is treated. At temperatures around 240 degrees C, VFA fraction present in WO supernatant is limited to 50% because of the presence of non-degraded fatty compounds and surfactants. Moreover, the COD reduction is limited to 70%. On the contrary, at 300 degrees C, COD removal efficiencies greater than 80% are achieved without any catalyst addition and, in addition, only highly biodegradable compounds remain in the oxidised liquor. In order to treat the residual ammonia nitrogen by biological processes, it is therefore necessary to obtain a VFA fraction as high as possible for achieving denitrification and then to operate the WO process at high temperature and without catalyst addition. PMID:11794648

  16. Wet oxidation of spent TBP/OK and interphase crud by H2O2

    International Nuclear Information System (INIS)

    Wet oxidation of simulated organic filth by hydrogen peroxide catalysed by Fe2+ is investigated. The factors influencing reactions such as H2O2 dosage, catalyst, pH-value and so on are studied. With regard to reagent addition manner, intermittent addition is advised for the utilization of H2O2, pH value of the system is 1-2. To assure fast startup and going along placidly of the reaction, a third of the catalyst is mixed with the filth before the oxidation, the other two thirds are added in the reacting solution continuously during the reaction process and finished the addition half an hour before the end of the reaction. TBP/OK, HDBP/OK and interphase crud can be decomposed effectively by H2O2. Finally, trivariant normal experiments are employed for determination of the optimal conditions. When the dosage of cruds is 2.00 g, the optimal conditions are pH=1, 10 mL H2O2, 10 mL 0.1 mol/L Fe2+. The element analysis and infrared spectroscopic analysis shows that the main component of the residual from the reaction is phosphate. (authors)

  17. The novel zinc cluster regulator Tog1 plays important roles in oleate utilization and oxidative stress response in Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Thepnok, Piyasuda; Ratanakhanokchai, Khanok; Soontorngun, Nitnipa, E-mail: nitnipa.soo@kmutt.ac.th

    2014-08-08

    Highlights: • TOG1 deletion results in defective growth on non-fermentable carbon sources. • Removal of TOG1 sensitizes cells to oxidative stress. • Tog1 directly binds and activates expression of oleate utilizing genes. • The Δtog1 cells display reduced peroxisomal content in oleate culture. • S. cerevisiae zinc cluster Tog1 is a novel activator of oleate utilization. - Abstract: Many zinc cluster proteins have been shown to play a role in the transcriptional regulation of glucose-repressible genes during glucose exhaustion and diauxic shift. Here, we studied an additional member of this family called Yer184c (herein called Tog1) for transcriptional regulator of oleate. Our results showed that a Δtog1 strain displays impaired growth with several non-fermentable carbons. Tog1 is also implicated in oxidative stress tolerance. Importantly, during the glucose–oleate shift, combined results from quantitative real time-PCR and chromatin immunoprecipitation (ChIP) experiments showed that Tog1 acts as a direct activator of oleate utilizing genes, encoded key enzymes in β-Oxidation and NADPH regeneration (POX1, FOX2, POT1 and IDP2), the glyoxylate shunt (MLS1 and ICL1), and gluconeogenesis (PCK1 and FBP1). A transmission electron microscopy (TEM) analysis of the Δtog1 strain assayed with oleate also revealed a substantial decrease in peroxisome abundance that is vital for fatty acid oxidation. Overall, our results clearly demonstrated that Tog1 is a newly characterized zinc cluster regulator that functions in the complex network of non-fermentable carbon metabolism in Saccharomycescerevisiae.

  18. The novel zinc cluster regulator Tog1 plays important roles in oleate utilization and oxidative stress response in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Highlights: • TOG1 deletion results in defective growth on non-fermentable carbon sources. • Removal of TOG1 sensitizes cells to oxidative stress. • Tog1 directly binds and activates expression of oleate utilizing genes. • The Δtog1 cells display reduced peroxisomal content in oleate culture. • S. cerevisiae zinc cluster Tog1 is a novel activator of oleate utilization. - Abstract: Many zinc cluster proteins have been shown to play a role in the transcriptional regulation of glucose-repressible genes during glucose exhaustion and diauxic shift. Here, we studied an additional member of this family called Yer184c (herein called Tog1) for transcriptional regulator of oleate. Our results showed that a Δtog1 strain displays impaired growth with several non-fermentable carbons. Tog1 is also implicated in oxidative stress tolerance. Importantly, during the glucose–oleate shift, combined results from quantitative real time-PCR and chromatin immunoprecipitation (ChIP) experiments showed that Tog1 acts as a direct activator of oleate utilizing genes, encoded key enzymes in β-Oxidation and NADPH regeneration (POX1, FOX2, POT1 and IDP2), the glyoxylate shunt (MLS1 and ICL1), and gluconeogenesis (PCK1 and FBP1). A transmission electron microscopy (TEM) analysis of the Δtog1 strain assayed with oleate also revealed a substantial decrease in peroxisome abundance that is vital for fatty acid oxidation. Overall, our results clearly demonstrated that Tog1 is a newly characterized zinc cluster regulator that functions in the complex network of non-fermentable carbon metabolism in Saccharomycescerevisiae

  19. Development of a novel wet oxidation process for hazardous and mixed wastes

    International Nuclear Information System (INIS)

    Many DOE waste streams and remediates contain complex and variable mixtures of organic compounds, toxic metals, and radionuclides. These materials are often dispersed in organic or inorganic matrices, such as personal protective equipment, various sludges, soils, and water. The over all objective of the effort described here is to develop a novel catalytic wet oxidation process for the treatment of these multi-component wastes, with the aim of providing a versatile, non-thermal method which will destroy hazardous organic compounds while simultaneously containing and concentrating toxic and radioactive metals for recovery or disposal in a readily stabilized matrix. The DETOX process uses a unique combination of metal catalysts to increase the rate of oxidation of organic materials. The metal catalysts are in the form of salts dissolved in a dilute acid solution. A typical catalyst composition is 60% ferric chloride, 3--4% hydrochloric acid, 0.13% platinum ions, and 0.13% ruthenium ions in a water solution. The catalyst solution is maintained at 423--473 K. Wastes are introduced into contact with the solution, where their organic portion is oxidized to carbon dioxide and water. If the organic portion is chlorinated, hydrogen chloride will be produced as a product. The process is a viable alternative to incineration for the treatment of organic mixed wastes. Estimated costs for waste treatment using the process are from $2.50/kg to $25.00/kg, depending on the size of the unit and the amount of waste processed. Process units can be mobile for on-site treatment of wastes. Results from phase 1 and 2, design and engineering studies, are described

  20. Influence of the different oxidation treatment on the performance of multi-walled carbon nanotubes in the catalytic wet air oxidation of phenol

    International Nuclear Information System (INIS)

    Highlights: ► Carbon nanotubes were used as catalysts in the catalytic wet air oxidation of phenol. ► Four chemical oxidants (HNO3/H2SO4, H2O2, O3 and air) were used to modify the CNTs. ► The O3-functionalized CNTs exhibit the highest activity and the perfect stability. - Abstract: Multi-walled carbon nanotubes (MWCNTs) functionalized by different oxidants (HNO3/H2SO4, H2O2, O3 and air) have been used as catalysts for the wet air oxidation of phenol. To investigate the effect of the oxidation conditions on the structure of the functionalized MWCNTs, various characterization techniques, e.g., scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) have been used. The MWCNTs treated with O3 and H2O2 show higher amounts of oxygen-containing functional groups and carboxylic acid groups, and a weaker acidic nature, in comparison with those treated with other oxidizing agents. All the functionalized MWCNTs exhibit good activity in the catalytic wet air oxidation (CWAO) of phenol. However, the MWCNTs treated with O3 show the highest activity with desirable stability in comparison with other functionalized MWCNTs, indicating that the functionalization of carbon nanotubes with O3 is a very promising strategy in synthesizing efficient catalysts for CWAO.

  1. Optimization of a cytochrome P450 oxidation system for enhancing protopanaxadiol production in Saccharomyces cerevisiae.

    Science.gov (United States)

    Zhao, Fanglong; Bai, Peng; Liu, Ting; Li, Dashuai; Zhang, Xiangmei; Lu, Wenyu; Yuan, Yingjin

    2016-08-01

    Ginsenosides, the major bioactive components of Panax ginseng, are regarded as promising high-value pharmaceutical compounds. In ginseng, ginsenosides are produced from their precursor protopanaxadiol. Recently, an artificial biosynthetic pathway of protopanaxadiol was built in Saccharomyces cerevisiae by introducing a P. ginseng dammarenediol-II synthase, a P. ginseng cytochrome P450-type protopanaxadiol synthase (PPDS), and a Arabidopsis thaliana NADPH-cytochrome P450 reductase (ATR1). In this engineered yeast strain, however, the low metabolic flux through PPDS resulted in a low productivity of protopanaxadiol. Moreover, health of the yeast cells was significantly affected by reactive oxygen species released by the pool coupling between PPDS and ATR1. To overcome the obstacles in protopanaxadiol production, PPDS was modified through transmembrane domain truncation and self-sufficient PPDS-ATR1 fusion construction in this study. The fusion enzymes conferred approximately 4.5-fold increase in catalytic activity, and 71.1% increase in protopanaxadiol production compared with PPDS and ATR1 co-expression. Our in vivo experiment indicated that the engineered yeast carrying fusion protein effectively converted 96.8% of dammarenediol-II into protopanaxadiol. Protopanaxadiol production in a 5 L bioreactor in fed-batch fermentation reached 1436.6 mg/L. Our study not only improved protopanaxadiol production in yeast, but also provided a generic method to improve activities of plant cytochrome P450 monooxygenases. This method is promising to be applied to other P450 systems in yeast. Biotechnol. Bioeng. 2016;113: 1787-1795. © 2016 Wiley Periodicals, Inc. PMID:26757342

  2. Treatment of biomass-gasification wastewaters by wet-air oxidation

    Energy Technology Data Exchange (ETDEWEB)

    English, C.J.

    1981-09-01

    Production of synthetic natural gas from gasification of biomass results in the generation of a high-strength wastewater that is difficult to treat by conventional means. This study investigated the use of wet air oxidation (WAO) as a treatment method for these wastewaters. A literature review was conducted to identify the suitability of WAO for the treatment of high-strength industrial wastewaters and to determine typical operating conditions for such treatment. Data presented in the literature showed that WAO should be suitable for treatment. Data presented in the literature showed that WAO should be suitable for treatment of biomass gasification wastewaters (BGW), and a laboratory treatability study was designed. BGW, having an initial chemical oxygen demand (COD) of 30,800 mg/1 and initial color of 183,000 APHA units, was treated in a laboratory autoclave for 20, 40, 60, 120, and 180 min at temperatures and pressures of 150/sup 0/C, 5.1 MPa (750 psi); 200/sup 0/C, 6.9 MPa (1000 psi); 250/sup 0/C, 10.3 MPa (1500 psi); and 300/sup 0/C, 13.8 MPa (2000 psi). Maximum COD removals of 0% for the 150/sup 0/C, 5.2 MPa (750 psi) runs; 40% for the 200/sup 0/C, 6.9 MPa (1000 psi) runs, 55% for the 250/sup 0/C, 10.3 MPa (1500 psi) runs; and 85% for the 300/sup 0/C, 13.8 MPa (2000 psi) runs were measured. Maximum color removals for these respective runs were 56%, 82%, 97%, and 99%. Initial removal rates of COD and color were observed to increase with reaction temperature. The experimental results suggest that oxidation of BGW organics by WAO occurs in a stepwise fashion with large organic molecules first being hydrolyzed and then partially oxidized to low molecular weight intermediates. Complete oxidation of these intermediates is more difficult and most easily accomplished at high reaction temperatures. The best application of WAO to treatment of BGW appears to be as a pretreatment to biological treatment and it is recommended that this application be investigated.

  3. Anaerobic treatability of liquid residue from wet oxidation of sewage sludge.

    Science.gov (United States)

    Bertanza, Giorgio; Galessi, Raniero; Menoni, Laura; Pedrazzani, Roberta; Salvetti, Roberta; Zanaboni, Sabrina

    2015-05-01

    Wet Oxidation (WO) of sewage sludge is a chemical oxidation of sludge at high temperatures and pressures by means of an oxygen-containing gas. The liquid stream originated by WO is easily biodegradable, and therefore, the recirculation to the biological Waste Water Treatment Plant (WWTP) may be a feasible solution. However, the WO effluent has a residual organic and nitrogen content so that its treatment may be required when the receiving WWTP has no surplus treatment capacity left. The aim of this research was the assessment of the anaerobic treatability of the WO liquid residue, in order to reduce the organic load to be recirculated to the WWTP, simultaneously promoting energy recovery. For this purpose, the liquid residue obtained during full scale WO tests on two different types of sludge was submitted to anaerobic digestion in a continuous flow pilot reactor (V = 5 L). Furthermore, batch tests were carried out in order to evaluate possible inhibition factors. Experimental results showed that, after the start-up/acclimation period (~130 days), Chemical Oxygen Demand (COD) removal efficiency was stably around 60% for about 120 days, despite the change in operating conditions. In the last phase of the experimental activity, COD removal reached 70% under the following treatment conditions: Hydraulic Retention Time (HRT) = 20 days, Volumetric Organic Loading Rate (VOLR) = 0.868 kg COD/m(3)/day, Organic Loading Rate per Volatile Suspended Solids (OLRvss) = 0.078 kg COD/kg VSS/day, temperature (T) = 36.5 °C, pH = 8. Energy balance calculation demonstrated anaerobic treatment sustainability. PMID:25035054

  4. Toluene removal by oxidation reaction in spray wet scrubber: experimental, modeling and optimization

    Directory of Open Access Journals (Sweden)

    Roumporn Nikom

    2006-11-01

    Full Text Available Toluene, an important volatile organic compound (VOC, is used in many kinds of industries, such as painting, printing, coating, and petrochemical industries. The emission of toluene causes serious air pollution, odor problem, flammability problem and affects human health. This paper proposes the removal of toluene from waste air using a spray wet scrubber combining the absorption and oxidation reaction. Aqueous sodium hypochlorite (NaOCl solution was used as the scrubbing liquid in the system. NaOCl, the strongest oxidative agent, presents an effective toluene removal. As the scrubbed toluene is reacted, recirculation of the scrubbing liquid could be operated with a constant removal efficiency throughout the operting time. The investigated variables affecting the removal efficiency were air flow rate, inlet toluene concentration, NaOCl concentration, scrubbing liquid flow rate and size of spray nozzle. Influence of the scrubbing parameters was experimentally studied to develop a mathematical model of the toluene removal efficiency. The removal model reveals that the increase of scrubbing liquid flow rate, toluene concentration, and NaOCl concentration together with the decrease of air flow rate and size of spray nozzle can increase the toluene removal efficiency. Optimization problem with an objective function and constraints was set to provide the maximum toluene removal efficiency and solved by Matlab optimization toolbox. The optimization constraints were formed from the mathematical model and process limitation. The solution of the optimization was an air flow rate of 100 m3/h, toluene concentration of 1500 ppm, NaOCl concentration of 0.02 mol/l, NaOCl solution feed rate of 0.8 m3/h, and spray nozzle size of 0.5 mm. Solution of the optimization gave the highest toluene removal efficiency of 91.7%.

  5. Catalytic wet oxidation of the pretreated synthetic pulp and paper mill effluent under moderate conditions.

    Science.gov (United States)

    Garg, Anurag; Mishra, I M; Chand, Shri

    2007-01-01

    In the present study, catalytic wet oxidation (CWO) was investigated for the destruction of organic pollutants in the thermally pretreated effluent from a pulp and paper mill under moderate temperature and pressure conditions. The thermal pretreatment studies were conducted at atmospheric pressure and 368K using copper sulfate as a catalyst. The thermal pretreatment reduced COD by about 61%. The filtrate of the thermal pretreatment step was used at pH 8.0 for CWO at 383-443K temperature and a total pressure of 0.85MPa for 4h. Catalysts used for the reaction include copper sulfate, 5% CuO/95% activated carbon, 60% CuO/40% MnO(2), and 60% CuO/40% CeO(2). Maximum COD reduction was found to be 89% during CWO step using 5% CuO/95% activated carbon with a catalyst loading of 8gl(-1) at 443K and 0.85MPa total pressure. Overall COD reduction for the pretreatment and the CWO was found to be 96%. Besides this, 60% CuO/40% CeO(2) catalyst also exhibited the similar activity as that of obtained with 5% CuO/95% activated carbon catalyst at 423K temperature and 0.85MPa total pressure. The pH of the solution during the experimental runs decreases initially due to the formation of carboxylic acid and then increases due to the decomposition of acids. PMID:16934854

  6. Energetic optimization of wet air oxidation process using experimental design coupled with process simulation

    International Nuclear Information System (INIS)

    Wet air oxidation process (WAO) is used for wastewater treatment, especially when it contains high chemical oxygen demand. With non-catalytic processes, temperatures between 200 and 350 °C and pressures between 15 and 30 MPa are generally applied. A method, based on the coupling of simulations and experimental design, is used to compare and optimize two reactors (adiabatic and isotherm), their volume being equal and fixed. The interest of an experimental design approach is to plan simulation and to present results in immediate response surface. Four parameters have been selected; temperature, pressure, chemical oxygen demand, air ratio. After achieving the 25 simulations of the “numerical design”, mass and energy balances were analysed through two energetic values integrated as the design responses: exergetic efficiency and minimum heat required by the process for the functioning. The surface response methodology determines which are the most influencing parameters on design responses. It also shows that temperature of reaction and air ratio are the most influencing parameters. At least elements to calculate the cost of the plant, for both reactors are given. Both reactors allow to get complete degradation of pollutants, but strategy of investment and control are opposite.

  7. Supported noble metal catalysts in the catalytic wet air oxidation of industrial wastewaters and sewage sludges.

    Science.gov (United States)

    Besson, M; Descorme, C; Bernardi, M; Gallezot, P; di Gregorio, F; Grosjean, N; Minh, D Pham; Pintar, A

    2010-12-01

    This paper reviews some catalytic wet air oxidation (CWAO) investigations of industrial wastewaters over platinum and ruthenium catalysts supported on TiO2 and ZrO2 formulated to be active and resistant to leaching, with particular focus on the stability of the catalyst. Catalyst recycling experiments were performed in batch reactors and long-term stability tests were conducted in trickle-bed reactors. The catalyst did not leach upon treatment of Kraft bleaching plant and olive oil mill effluents, and could be either recycled or used for long periods of time in continuous reactors. Conversely, these catalysts were rapidly leached when used to treat effluents from the production of polymeric membranes containing N,N-dimethylformamide. The intermediate formation of amines, such as dimethylamine and methylamine with a high complexing capacity for the metal, was shown to be responsible for the metal leaching. These heterogeneous catalysts also deactivated upon CWAO of sewage sludges due to the adsorption of the solid organic matter. Pre-sonication of the sludge to disintegrate the flocs and improve solubility was inefficient. PMID:21214003

  8. Determination of boron in graphite by a wet oxidation decomposition/curcumin photometric method

    International Nuclear Information System (INIS)

    The wet oxidation decomposition of graphite materials has been studied for the accurate determination of boron using a curcumin photometric method. A graphite sample of 0.5 g was completely decomposed with a mixture of 5 ml of sulfuric acid, 3 ml of perchloric acid, 0.5 ml of nitric acid and 5 ml of phosphoric acid in a silica 100 ml Erlenmeyer flask fitted with an air condenser at 200degC. Any excess of perchloric and nitric acids in the solution was removed by heating on a hot plate at 150degC. Boron was distilled with methanol, and then recovered in 10 ml of 0.2 M sodium hydroxide. The solution was evaporated to dryness. To the residue were added curcumin-acetic acid and sulfuric-acetic acid. The mixture was diluted with ethanol, and the absorbance at 555 nm was measured. The addition of 5 ml of phosphoric acid proved to be effective to prevent any volatilization loss of boron during decomposition of the graphite sample and evaporation of the resulting solution. The relative standard deviation was 4-8% for samples with 2 μg g-1 levels of boron. The results on CRMs JAERI-G5 and G6 were in good agreement with the certified values. (author)

  9. Decomposition and Mineralization of Dimethyl Phthalate in an Aqueous Solution by Wet Oxidation

    Directory of Open Access Journals (Sweden)

    Dar-Ren Ji

    2015-01-01

    Full Text Available Dimethyl phthalate (DMP was treated via wet oxygen oxidation process (WOP. The decomposition efficiency ηDMP of DMP and mineralization efficiency ηTOC of total organic carbons were measured to evaluate the effects of operation parameters on the performance of WOP. The results revealed that reaction temperature T is the most affecting factor, with a higher T offering higher ηDMP and ηTOC as expected. The ηDMP increases as rotating speed increases from 300 to 500 rpm with stirring enhancement of gas liquid mass transfer. However, it exhibits reduction effect at 700 rpm due to purging of dissolved oxygen by overstirring. Regarding the effects of pressure PT, a higher PT provides more oxygen for the forward reaction with DMP, while overhigh PT increases the absorption of gaseous products such as CO2 and decomposes short-chain hydrocarbon fragments back into the solution thus hindering the forward reaction. For the tested PT of 2.41 to 3.45 MPa, the results indicated that 2.41 MPa is appropriate. A longer reaction time of course gives better performance. At 500 rpm, 483 K, 2.41 MPa, and 180 min, the ηDMP and ηTOC are 93 and 36%, respectively.

  10. Engineering the Saccharomyces cerevisiae β-oxidation pathway to increase medium chain fatty acid production as potential biofuel.

    Directory of Open Access Journals (Sweden)

    Liwei Chen

    Full Text Available Fatty acid-derived biofuels and biochemicals can be produced in microbes using β-oxidation pathway engineering. In this study, the β-oxidation pathway of Saccharomyces cerevisiae was engineered to accumulate a higher ratio of medium chain fatty acids (MCFAs when cells were grown on fatty acid-rich feedstock. For this purpose, the haploid deletion strain Δpox1 was obtained, in which the sole acyl-CoA oxidase encoded by POX1 was deleted. Next, the POX2 gene from Yarrowia lipolytica, which encodes an acyl-CoA oxidase with a preference for long chain acyl-CoAs, was expressed in the Δpox1 strain. The resulting Δpox1 [pox2+] strain exhibited a growth defect because the β-oxidation pathway was blocked in peroxisomes. To unblock the β-oxidation pathway, the gene CROT, which encodes carnitine O-octanoyltransferase, was expressed in the Δpox1 [pox2+] strain to transport the accumulated medium chain acyl-coAs out of the peroxisomes. The obtained Δpox1 [pox2+, crot+] strain grew at a normal rate. The effect of these genetic modifications on fatty acid accumulation and profile was investigated when the strains were grown on oleic acids-containing medium. It was determined that the engineered strains Δpox1 [pox2+] and Δpox1 [pox2+, crot+] had increased fatty acid accumulation and an increased ratio of MCFAs. Compared to the wild-type (WT strain, the total fatty acid production of the strains Δpox1 [pox2+] and Δpox1 [pox2+, crot+] were increased 29.5% and 15.6%, respectively. The intracellular level of MCFAs in Δpox1 [pox2+] and Δpox1 [pox2+, crot+] increased 2.26- and 1.87-fold compared to the WT strain, respectively. In addition, MCFAs in the culture medium increased 3.29-fold and 3.34-fold compared to the WT strain. These results suggested that fatty acids with an increased MCFAs ratio accumulate in the engineered strains with a modified β-oxidation pathway. Our approach exhibits great potential for transforming low value fatty acid

  11. Oxidation Behavior of Mo-Si-B Alloys in Wet Air; TOPICAL

    International Nuclear Information System (INIS)

    Multiphase composite alloys based on the Mo-Si-B system are candidate materials for ultra-high temperature applications. In non load-bearing uses such as thermal barrier coatings or heat exchangers in fossil fuel burners, these materials may be ideally suited. The present work investigated the effect of water vapor on the oxidation behavior of Mo-Si-B phase assemblages. Three alloys were studied: Alloy 1= Mo(sub 5)Si(sub 3)B(sub x) (T1)- MoSi(sub 2)- MoB, Alloy 2= T1- Mo(sub 5)SiB(sub 2) (T2)- Mo(sub 3)Si, and Alloy 3= Mo- T2- Mo(sub 3)Si. Tests were conducted at 1000 and 1100C in controlled atmospheres of dry air and wet air nominally containing 18, 55, and 150 Torr H(sub 2)O. The initial mass loss of each alloy was approximately independent of the test temperature and moisture content of the atmosphere. The magnitude of these initial losses varied according to the Mo content of the alloys. All alloys formed a continuous, external silica scale that protected against further mass change after volatilization of the initially formed MoO(sub 3). All alloys experienced a small steady state mass change, but the calculated rates cannot be quantitatively compared due to statistical uncertainty in the individual mass measurements. Of particular interest is that Alloy 3, which contains a significant volume fraction of Mo metal, formed a protective scale. All alloys formed varying amounts of subscale Mo and MoO(sub 2). This implies that oxygen transport through the external silica scale has been significantly reduced. For all alloys, water vapor accelerated the growth of a multiphase interlayer at the silica scale/unoxidized alloy interface. This interlayer is likely composed of fine Mo and MoO(sub 2) that is dispersed within a thin silica matrix. Alloy 3 was particularly sensitive to water accelerated growth of this interlayer. At 1100 C, the scale thickness after 300 hours increased from about 20 mm in dry air to nearly 100 mm in wet air

  12. Conditioning of Si-interfaces by wet-chemical oxidation: Electronic interface properties study by surface photovoltage measurements

    Energy Technology Data Exchange (ETDEWEB)

    Angermann, Heike, E-mail: angermann@helmholtz-berlin.de

    2014-09-01

    Highlights: • Determination of electronic interface properties by contact-less surface photovoltage (SPV) technique. • Systematic correlations of substrate morphology and surface electronic properties. • Optimization of surface pre-treatment for flat, saw damage etched, and textured Si solar cell substrates. • Ultra-thin passivating Si oxide layers with low densities of rechargeable states by wet-chemical oxidation and subsequent annealing. • Environmentally acceptable processes, utilizing hot water, diluted HCl, or ozone low cost alternative to current approaches with concentrated chemicals. • The effect of optimized wet-chemical pre-treatments can be preserved during subsequent layer deposition. - Abstract: The field-modulated surface photovoltage (SPV) method, a very surface sensitive technique, was utilized to determine electronic interface properties on wet-chemically oxidized and etched silicon (Si) interfaces. The influence of preparation-induced surface micro-roughness and un-stoichiometric oxides on the resulting the surface charge, energetic distribution D{sub it}(E), and density D{sub it,min} of rechargeable states was studied by simultaneous, spectroscopic ellipsometry (SE) measurements on polished Si(111) and Si(100) substrates. Based on previous findings and new research, a study of conventional and newly developed wet-chemical oxidation methods was established, correlating the interactions between involved oxidizing and etching solutions and the initial substrate morphology to the final surface conditioning. It is shown, which sequences of wet-chemical oxidation and oxide removal, have to be combined in order to achieve atomically smooth, hydrogen terminated surfaces, as well as ultra-thin oxide layers with low densities of rechargeable states on flat, saw damage etched, and textured Si substrates, as commonly applied in silicon device and solar cell manufacturing. These conventional strategies for wet-chemical pre-treatment are mainly

  13. Continuous wet oxidation pretreatment of lignocellulosic biomass with subsequent continuous ethanol production; Kontinuerlig vaadoxidationsforbehandling af lignocelluloseholdige biomasser med efterfoelgende kontinuerlig ethanolfremstilling

    Energy Technology Data Exchange (ETDEWEB)

    Ahring, B.K.; Torry-Smith, M.; Loeth, A.H.

    2001-07-01

    In this project the possibility of implementing a UASB-reactor for detoxification of the recirculation water is investigated. Bioethanol- effluent (BEE) made from wet-oxidized wheat straw (60 g-wheat straw/l-water) fermented with Saccharomyces cerevisiae and Thermoanaerobacter mathranii A3M4 is in this project used to simulate the effluent from a commercial bioethanol plant. To investigate the gas potential and conversion of inhibitors, BEE is investigated both in batch and in a laboratory scale UASB reactor. In batch tests the conversion of acetovanillon, 2-furan acid and 4-hydroxyacetophenon was investigated with the substances themselves, as single substrat, and by co-digestion with BEE. The experiments show that the conversion of the three substances together with BEE had a positive influence on the decomposition and the inhibition levels. Tests with conversion of BEE in a laboratory scale UASB-reactor showed that by loading up to 29 g-COD/l it was possible to obtain a COD-reduction at 80% (w/w). At the same time GC-analyses of vanillin acid, homo vanillin acid, aceton vanillon, syringon acid, acetosyringon, syringol, 4-hydroxybenzo acid, 4-hydroxbenzaldenhyde, 2-furan acid, and phenol showed that all these substances were converted in the UASB-reactor. Economical calculations carried out on the basis of the results from the experiments indicate that the implementation of a UASB-cleaning step for cleaning the bioethanol process water can be carried out with a economical profit, which among other means a short payback time on the investment. It is things concluded that the implementation of a UASB-cleaning step is a qualified method to detoxify process water for bioethanol production and thereby reduce the total production costs of the commercial bioethanol production based on lignocelluslose materials. The necessity of tests with repeated recirculations are indicated, because continuous reuse of the process water can result in up-concentration of any inhibitors

  14. Catalytic oxidation with Al-Ce-Fe-PILC as a post-treatment system for coffee wet processing wastewater.

    Science.gov (United States)

    Sanabria, Nancy R; Peralta, Yury M; Montañez, Mardelly K; Rodríguez-Valencia, Nelson; Molina, Rafael; Moreno, Sonia

    2012-01-01

    The effluent from the anaerobic biological treatment of coffee wet processing wastewater (CWPW) contains a non-biodegradable compound that must be treated before it is discharged into a water source. In this paper, the wet hydrogen peroxide catalytic oxidation (WHPCO) process using Al-Ce-Fe-PILC catalysts was researched as a post-treatment system for CWPW and tested in a semi-batch reactor at atmospheric pressure and 25 °C. The Al-Ce-Fe-PILC achieved a high conversion rate of total phenolic compounds (70%) and mineralization to CO(2) (50%) after 5 h reaction time. The chemical oxygen demand (COD) of coffee processing wastewater after wet hydrogen peroxide catalytic oxidation was reduced in 66%. The combination of the two treatment methods, biological (developed by Cenicafé) and catalytic oxidation with Al-Ce-Fe-PILC, achieved a 97% reduction of COD in CWPW. Therefore, the WHPCO using Al-Ce-Fe-PILC catalysts is a viable alternative for the post-treatment of coffee processing wastewater. PMID:22907449

  15. Thermodynamic and kinetic study of phenol degradation by a non-catalytic wet air oxidation process.

    Science.gov (United States)

    Lefèvre, Sébastien; Boutin, Olivier; Ferrasse, Jean-Henry; Malleret, Laure; Faucherand, Rémy; Viand, Alain

    2011-08-01

    This work is dedicated to an accurate evaluation of thermodynamic and kinetics aspects of phenol degradation using wet air oxidation process. Phenol is a well known polluting molecule and therefore it is important having data of its behaviour during this process. A view cell is used for the experimental study, with an internal volume of 150 mL, able to reach pressures up to 30 MPa and temperatures up to 350°C. Concerning the thermodynamic phase equilibria, experimental and modelling results are obtained for different binary systems (water/nitrogen, water/air) and ternary system (water/nitrogen/phenol). The best model is the Predictive Soave Redlich Kwong one. This information is necessary to predict the composition of the gas phase during the process. It is also important for an implementation in a process simulation. The second part is dedicated to kinetics evaluation of the degradation of phenol. Different compounds have been detected using GC coupled with a MS. A kinetic scheme is deduced, taking into account the evolution of phenol, hydroquinones, catechol, resorcinol and acetic acid. The kinetic parameters are calculated for this scheme. These data are important to evaluate the evolution of the concentration of the different polluting molecules during the process. A simplified kinetic scheme, which can be easily implemented in a process simulation, is also determined for the direct degradation of phenol into H(2)O and CO(2). The Arrhenius law data obtained for the phenol disappearance are the following: k=1.8×10(6)±3.9×10(5)M(-1)s(-1) (pre-exponential factor) and E(a)=77±8 kJ mol(-1) (activation energy). PMID:21700312

  16. THE EFFECT OF SEVERAL NON-OXIDIZING BIOCIDES ON FINE PAPER WET-END CHEMISTRY

    OpenAIRE

    Patrick Huber; Bruno Carré; Elisa Zeno

    2010-01-01

    Biocide programs have become necessary in most fine paper manufacturing circuits, as drastic reduction of fresh water consumption in the industry enhances microbial development. Depending on their chemical nature, biocides may interfere with typical wet-end chemistry additives and furnish. A reference wet-end chemistry was set (including fixing aid, dry strength aid, sizing agent, and retention system), then biocides were added to the furnish (bleached virgin fibres + mineral filler) prior to...

  17. Wet Oxidation of Crude Manure and Manure Fibers: Substrate Characteristics Influencing the Pretreatment Efficiency for Increasing the Biogas Yield of Manure

    DEFF Research Database (Denmark)

    Uellendahl, Hinrich; Mladenovska, Zuzana; Ahring, Birgitte Kiær

    2007-01-01

    The biogas yield of manure is typically lower than 25 m3/t due to its low dry matter content and its high ratio of lignocellulosic fibers that are recalcitrant towards anaerobic digestion. A new pre-treatment method – wet oxidation – has been tested for disruption of the lignocellulosic fiber...... structure with subsequent higher degradation efficiencies and methane yields. A screening of crude manure and the separated fiber fraction shows that wet oxidation is more adequate for treatment of high concentrated solid fraction than for crude manure and an increase of 35% in biogas yield can be gained...... from wet oxidation of digested fibers. The wet oxidation treatment of the manure fiber fraction has to be carefully adjusted in order to achieve the highest increase in biogas yield for the manure fiber fraction under low production of inhibiting compounds and low losses of valuable organic matter....

  18. Functionalization to control microstructural, optical, electronic and wetting properties of metal oxide surfaces

    Science.gov (United States)

    Singh, Jagdeep

    This thesis focuses on engineering the surface chemistry of oxide surfaces in order to control their microstructural, optical, electronic and wetting properties. Several different types of experiments have been performed to tailor the properties of silicon oxide, titanium dioxide, and zinc oxide surfaces. Applications of this work include organic electronics, sensors and nanomanufacturing. Adsorption of 3-mercaptopropyltrimethoxysilane (MPS) on hydroxylated silicon oxide substrates by immersion in MPS solution or exposure to MPS vapor has been compared using X-ray photoelectron spectroscopy (XPS). To aid the interpretation, MPS has also been cryogenically condensed in ultrahigh vacuum (UHV) onto gold surfaces. Condensation of MPS vapor on gold in the absence of water does not result in MPS polymerization, as evidenced by multilayer desorption upon warming to room temperature. The C1s XPS spectrum has been used to infer the relative abundance of methoxy groups. Vapor-deposition on hydroxylated silicon oxide leads to an unpolymerized MPS monolayer consisting of molecules with two methoxy groups. UV induced hydrophilicity of titanium dioxide surfaces could possibly be used to provide a means of registration and alignment in high-rate nanomanufacturing applications or to induce transfer of nanoelements. In order to understand the nature and magnitude of intermolecular forces, force-distance curves have been measured on TiO2. Toward the goal of possibly using light to induce nanoparticle transfer, force curves have been recorded using an SiO2 colloidal probe before and after irradiating the TiO 2 surface with UV light. In order to eliminate the effects of capillary forces, the relative humidity has been kept below 1% by flowing either N 2 or N2/O2 (1:1) into the AFM chamber. In a dry nitrogen environment, no difference is observed in adhesive forces measured with and without UV exposure. Gold-coated atomic force microscope (AFM) tips functionalized with amine-, hydroxyl

  19. Role of Bismuth Oxide in Bi-MCo2O4(M=Co,Ni,Cu,Zn) Catalysts for Wet Air Oxidation of Acetic Acid

    Institute of Scientific and Technical Information of China (English)

    JIANG Peng-bo; CHENG Tie-xin; ZHUANG Hong; CUI Xiang-hao; BI Ying-li; ZHEN Kai-ji

    2004-01-01

    Two series of cobalt(Ⅲ)-containing spinel catalysts were prepared by the decomposition of the corresponding nitrates. The catalysts doped with bismuth oxide exhibit a higher activity in the wet air oxidation of acetic acid than those without dopant bismuth oxide. The catalysts were investigated by XRD, TEM, ESR, UV-DRS and XPS, and the interaction between Co and Bi was studied as well. It has been found that nano-sized bismuth oxide is paved on the surface of cobalt spinel crystal and the structures of cobalt(Ⅲ)-containing spinel are still maintained. The shift of the binding energy of Bi4f7/2 is related to the catalytic activity of these catalysts doped with bismuth oxide.

  20. Electronic interface properties of silicon substrates after ozone based wet-chemical oxidation studied by SPV measurements

    International Nuclear Information System (INIS)

    The preparation of ultra-thin oxide layers on mono-crystalline silicon substrate surfaces with ozone dissolved in ultra pure water at ambient temperature was investigated as a low cost alternative to current wet-chemical cleaning and passivation processes in solar cell manufacturing. Surface photovoltage technique was applied as fast, nondestructive, and surface sensitive method, to provide detailed information about the influence of oxidation rate and substrate surface morphology on electronic properties of the oxidised silicon interfaces and subsequently prepared hydrogen terminated surfaces. Sequences of wet-chemical oxidation in ozone containing ultra pure water and subsequent oxide removal in diluted hydrofluoric acid solution could be utilised to prepare hydrophobic substrates, which are predominantly required as starting point for layer deposition and contact formation. On so prepared hydrogen-terminated substrates values of interface state densities Dit,min ≈ 5 × 1011 eV-1 cm-2 could be achieved, comparable to values obtained on the same substrates by the standard RCA process followed by HF dip.

  1. Electronic interface properties of silicon substrates after ozone based wet-chemical oxidation studied by SPV measurements

    Science.gov (United States)

    Angermann, Heike; Wolke, Klaus; Gottschalk, Christiane; Moldovan, Ana; Roczen, Maurizio; Fittkau, Jens; Zimmer, Martin; Rentsch, Jochen

    2012-08-01

    The preparation of ultra-thin oxide layers on mono-crystalline silicon substrate surfaces with ozone dissolved in ultra pure water at ambient temperature was investigated as a low cost alternative to current wet-chemical cleaning and passivation processes in solar cell manufacturing. Surface photovoltage technique was applied as fast, nondestructive, and surface sensitive method, to provide detailed information about the influence of oxidation rate and substrate surface morphology on electronic properties of the oxidised silicon interfaces and subsequently prepared hydrogen terminated surfaces. Sequences of wet-chemical oxidation in ozone containing ultra pure water and subsequent oxide removal in diluted hydrofluoric acid solution could be utilised to prepare hydrophobic substrates, which are predominantly required as starting point for layer deposition and contact formation. On so prepared hydrogen-terminated substrates values of interface state densities Dit,min ≈ 5 × 1011 eV-1 cm-2 could be achieved, comparable to values obtained on the same substrates by the standard RCA process followed by HF dip.

  2. Controlling the shape and gap width of silicon electrodes using local anodic oxidation and anisotropic TMAH wet etching

    International Nuclear Information System (INIS)

    A simple method for fabricating silicon electrodes with various shapes and gap widths was designed using the special properties of anisotropic tetramethylammonium hydroxide (TMAH) wet etching and local anodic oxidation (LAO). A statistical system was used for the optimization of the parameters of the LAO process to facilitate a better understanding and precise analysis of the process. Analyses of the interaction effects among the significant factors of LAO showed that the relative humidity and applied voltage were interdependent. They had the strongest interaction effect on the dimensions of the oxide mask. TMAH with a concentration of 25% was used as an etchant solution in (1 0 0) silicon with a rectangular oxide mask. The observed undercutting at convex corners, tip shape of emitters and gap widths of electrodes were exactly consistent with theoretical studies. Combination of the LAO method and anisotropic TMAH wet etching was successfully used to fabricate Si nano-gap electrodes. This fabrication method of sharp and round tip emitters was simple, controllable and faster than common techniques. These results indicate that the method can be a new approach for studying the electrical properties of nano-gap electrodes. (paper)

  3. Controlling the shape and gap width of silicon electrodes using local anodic oxidation and anisotropic TMAH wet etching

    Science.gov (United States)

    Rouhi, Jalal; Mahmud, Shahrom; Derita Hutagalung, Sabar; Naderi, Nima; Kakooei, Saeid; Johar Abdullah, Mat

    2012-06-01

    A simple method for fabricating silicon electrodes with various shapes and gap widths was designed using the special properties of anisotropic tetramethylammonium hydroxide (TMAH) wet etching and local anodic oxidation (LAO). A statistical system was used for the optimization of the parameters of the LAO process to facilitate a better understanding and precise analysis of the process. Analyses of the interaction effects among the significant factors of LAO showed that the relative humidity and applied voltage were interdependent. They had the strongest interaction effect on the dimensions of the oxide mask. TMAH with a concentration of 25% was used as an etchant solution in (1 0 0) silicon with a rectangular oxide mask. The observed undercutting at convex corners, tip shape of emitters and gap widths of electrodes were exactly consistent with theoretical studies. Combination of the LAO method and anisotropic TMAH wet etching was successfully used to fabricate Si nano-gap electrodes. This fabrication method of sharp and round tip emitters was simple, controllable and faster than common techniques. These results indicate that the method can be a new approach for studying the electrical properties of nano-gap electrodes.

  4. Catalytic wet-air oxidation of lignin in a three-phase reactor with aromatic aldehyde production

    OpenAIRE

    Sales F.G.; Abreu C.A.M.; Pereira J. A. F. R.

    2004-01-01

    In the present work a process of catalytic wet air oxidation of lignin obtained from sugar-cane bagasse is developed with the objective of producing vanillin, syringaldehyde and p-hydroxybenzaldehyde in a continuous regime. Palladium supported on g-alumina was used as the catalyst. The reactions in the lignin degradation and aldehyde production were described by a kinetic model as a system of complex parallel and series reactions, in which pseudo-first-order steps are found. For the purpose o...

  5. Energy balance and cost-benefit analysis of biogas production from perennial energy crops pretreated by wet oxidation

    DEFF Research Database (Denmark)

    Uellendahl, Hinrich; Wang, Guangtao; Møller, Henrik B.;

    2008-01-01

    conversion into biogas in anaerobic digestion plants shows however much lower specific methane yields for the raw perennial crops like miscanthus and willow due to their lignocellulosic structure. Without pretreatment the net energy gain is therefore lower for the perennials than for corn. When applying wet...... oxidation to the perennial crops, however, the specific methane yield increases significantly and the ratio of energy output to input and of costs to benefit for the whole chain of biomass supply and conversion into biogas becomes higher than for corn. This will make the use of perennial crops as energy...

  6. Wet oxidation treatment of organic household waste enriched with wheat straw for simultaneous saccharification and fermentation into ethanol

    DEFF Research Database (Denmark)

    Lissens, G.; Klinke, H.B.; Verstraete, W.; Ahring, Birgitte Kiær; Thomsen, Anne Belinda

    2004-01-01

    -toxic carboxylic acids mainly (2.2-4.5 % on DS basis). Simultaneous saccharification and fermentation (SSF) of the treated waste at 10% DS by Saccharomyces cerevisae yielded average ethanol concentrations of 16.5 to 22 g l(-1) for enzyme loadings of 5 and 25 FPU g(-1) DS, respectively. The cellulose to ethanol...... conversion efficiency during SSF was 50, 62 65 and 70% for a total enzyme loading of 5, 10, 15 and 25 FPU g(-1) DS, respectively. Hence, this study shows that wet oxidation is a suitable pre-treatment for the conversion of organic waste carbohydrates into ethanol and that compatible conversion yields (60...

  7. Influence of wet etching time cycles on morphology features of thin porous Anodic Aluminum oxide (AAO) template for nanostructure's synthesis

    Science.gov (United States)

    Chahrour, Khaled M.; Ahmed, Naser M.; Hashim, M. R.; Elfadill, Nezar G.; Al-Diabat, Ahmad M.; Bououdina, M.

    2015-12-01

    This study examines the influence of chemical wet etching time cycles on the morphological features of thin porous AAO template. Pore widening via wet-etching treatment at room temperature was found to modify the pore quality of AAO template and reduces the barrier layer on the bottom of AAO pore array in order to facilitate uniform electrodeposition of nanostructures onto AAO template. High quality AAO pore arrays with different mean pore diameters (64, 70, and 87 nm) were prepared under controllable pore-widening time cycles of 10, 30 and 45 min at room temperature, respectively. The AAO templates and the produced Cu nanorods were characterized using FESEM, EDX, XRD and AFM. The results indicate that the morphology of the aligned arrays of Cu nanorods is strongly affected by the duration of etching and the removal of AAO template. This study showed that the optimum etching duration required to maintain the aligned nanorods without any fracture is approximately 5 min. In addition, the regular hemispherical concave Al surface ensuring the self-ordering of AAO pore can be established when striping is employed for 45 min. Thus, it can be inferred that the duration of wet etching treatment (striping) of Al oxide film performed after the first-step anodization plays a vital role in the final arrangement of nanopores.

  8. Influence the oxidant action of selenium in radiosensitivity induction and cell death in yeast Saccharomyces cerevisiae; Influencia da acao oxidante do selenio na inducao da radiossensibilidade e morte celular na levedura Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Porto, Barbara Abranches de Araujo

    2012-07-01

    Ionizing radiations are from both natural sources such as from anthropogenic sources. Recently, radiotherapy has emerged as one of the most common therapies against cancer. Co-60 irradiators (cobalt-60 linear accelerators) are used to treat of malignant tumors routinely in hospitals around the world. Exposure to ionizing radiation can induce changes in cellular macromolecules and affect its functions, because they cause radiolysis of the water molecule generating reactive oxygen species, which can cause damage to virtually all organelles and cell components known as oxidative damage that can culminate in oxidative stress. Oxidative stress is a situation in which the balance between oxidants and antioxidants is broken resulting in excessive production of reactive species, it is not accompanied by the increase in antioxidant capacity, making it impossible to neutralize them. Selenium is a micronutrient considered as antioxidant, antiinflammatory, which could prevent cancer. Selenium in biological system exists as seleno proteins. Nowadays, 25 human seleno proteins have been identified, including glutathione peroxidase, an antioxidant enzyme. Yeasts have the ability to incorporate various metals such as iron, cadmium, zinc and selenium, as well as all biological organisms. The yeast Saccharomyces cerevisiae, unlike mammalian cells is devoid of seleno proteins, being considered as a practical model for studies on the toxicity of selenium, without any interference from the metabolism of seleno proteins. Moreover, yeast cells proliferate through the fermentation, the microbial equivalent of aerobic glycolysis in mammals and the process is also used by tumors. Several reports show that the pro-oxidante effects and induced toxic selenium compounds occur at lower doses and in malignant cells compared with benign cells. Therefore selenium giving a great therapeutic potential in cancer treatment .Our objective was to determine whether selenium is capable to sensitize yeasts

  9. Catalytic wet-air oxidation of lignin in a three-phase reactor with aromatic aldehyde production

    Directory of Open Access Journals (Sweden)

    Sales F.G.

    2004-01-01

    Full Text Available In the present work a process of catalytic wet air oxidation of lignin obtained from sugar-cane bagasse is developed with the objective of producing vanillin, syringaldehyde and p-hydroxybenzaldehyde in a continuous regime. Palladium supported on g-alumina was used as the catalyst. The reactions in the lignin degradation and aldehyde production were described by a kinetic model as a system of complex parallel and series reactions, in which pseudo-first-order steps are found. For the purpose of producing aromatic aldehydes in continuous regime, a three-phase fluidized reactor was built, and it was operated using atmospheric air as the oxidizer. The best yield in aromatic aldehydes was of 12%. The experimental results were compatible with those values obtained by the pseudo-heterogeneous axial dispersion model (PHADM applied to the liquid phase.

  10. Wet-chemical green synthesis of L-lysine amino acid stabilized biocompatible iron-oxide magnetic nanoparticles.

    Science.gov (United States)

    Krishna, Rahul; Titus, Elby; Krishna, Rohit; Bardhan, Neelkanth; Bahadur, Dhirendra; Gracio, José

    2012-08-01

    In this paper, we report a novel method for the synthesis of L-Lysine (lys) amino acid coated maghemite (gamma-Fe2O3) magnetic nanoparticles (MNPs). The facile and cost effective method permitted preparation of the high-quality superparamagnetic gamma-Fe2O3 MNPs with hydrophilic and biocompatible nature. For this work, first we synthesized magnetite phase Fe3O4/lys by wet chemical method and oxidized to y-Fe2O3 in controlled oxidizing environment, as evidenced by XRD and VSM magnetometry. The crystallite size and magnetization of gamma-Fe2O3/lys MNPs was found to be 14.5 nm, 40.6 emu/gm respectively. The surface functionalization by L-lysine amino acid and metal-ligand bonding was also confirmed by FTIR spectroscopy. The hydrodynamic diameter, colloidal stability and surface charge on MNPs were characterized by DLS and zeta potential analyser. PMID:22962801

  11. Chemical treatment of secondary waste solutions resulting from wet oxidative degradation of spent ion-exchange resins

    International Nuclear Information System (INIS)

    The present experimental work has been carried out to evaluate the chemical treatment process of radioactive secondary waste solutions resulting from the wet oxidative degradation of simulated spent radioactive cation-exchange resins using hydrogen peroxide as oxidant. The present study aims mainly to evaluate the ability of ferrocyanide compound of nickel for selective fixation of radio-cesium from the secondary waste solution in presence of traces of soluble organic residues. Based on the data obtained, it was found that, using 5 x 10-3 of nickel ferrocyanide, at ph range from 1-9 and in the presence of traces of soluble organic carbon, more than 99% of the radiocesium initially found could be efficiently removed from the secondary radioactive waste solutions under consideration

  12. A compact process for the treatment of olive mill wastewater by combining wet hydrogen peroxide catalytic oxidation and biological techniques

    International Nuclear Information System (INIS)

    A system based on combined actions of catalytic wet oxidation and microbial technologies for the treatment of highly polluted OMW containing polyphenols was studied. The wet hydrogen peroxide catalytic oxidation (WHPCO) process has been investigated in the semi-batch mode at atmospheric pressure, using aluminium-iron-pillared inter layer clay ((Al-Fe)PILC), under two different catalytic processes: ((Al-Fe)PILC/H2O2/ultraviolet radiations) at 25 deg. C and ((Al-Fe)PILC/H2O2) at 50 deg. C. The results show that raw OMW was resistant to the photocatalytic process. However ((Al-Fe)PILC/H2O2), system operating at 50 deg. C reduced considerably the COD, colour and total phenolic contents, and thus decreased the inhibition of the marine photobacteria Vibrio fischeri luminescence by 70%. This study also examined the feasibility of coupling WHPCO and anaerobic digestion treatment. Biomethanisation experiments performed with raw OMW or pre-treated OMW proved that pre-treatments with ((Al-Fe)PILC/H2O2) system, for more than 2 h, resulted in higher methane production. Both untreated OMW as well as 2-h pre-treated OMW revealed as toxic to anaerobic bacteria.

  13. A compact process for the treatment of olive mill wastewater by combining wet hydrogen peroxide catalytic oxidation and biological techniques

    Energy Technology Data Exchange (ETDEWEB)

    Azabou, Samia [Laboratoire des BioProcedes, Centre de Biotechnologie de Sfax, BP 1177, 3018 Sfax (Tunisia); Najjar, Wahiba [Laboratoire de Chimie des Materiaux et Catalyse, Faculte des Sciences de Tunis, Campus Universitaire, 2092 Tunis (Tunisia); Bouaziz, Mohamed [Laboratoire des BioProcedes, Centre de Biotechnologie de Sfax, BP 1177, 3018 Sfax (Tunisia); Ghorbel, Abdelhamid [Laboratoire de Chimie des Materiaux et Catalyse, Faculte des Sciences de Tunis, Campus Universitaire, 2092 Tunis (Tunisia); Sayadi, Sami, E-mail: sami.sayadi@cbs.rnrt.tn [Laboratoire des BioProcedes, Centre de Biotechnologie de Sfax, BP 1177, 3018 Sfax (Tunisia)

    2010-11-15

    A system based on combined actions of catalytic wet oxidation and microbial technologies for the treatment of highly polluted OMW containing polyphenols was studied. The wet hydrogen peroxide catalytic oxidation (WHPCO) process has been investigated in the semi-batch mode at atmospheric pressure, using aluminium-iron-pillared inter layer clay ((Al-Fe)PILC), under two different catalytic processes: ((Al-Fe)PILC/H{sub 2}O{sub 2}/ultraviolet radiations) at 25 deg. C and ((Al-Fe)PILC/H{sub 2}O{sub 2}) at 50 deg. C. The results show that raw OMW was resistant to the photocatalytic process. However ((Al-Fe)PILC/H{sub 2}O{sub 2}), system operating at 50 deg. C reduced considerably the COD, colour and total phenolic contents, and thus decreased the inhibition of the marine photobacteria Vibrio fischeri luminescence by 70%. This study also examined the feasibility of coupling WHPCO and anaerobic digestion treatment. Biomethanisation experiments performed with raw OMW or pre-treated OMW proved that pre-treatments with ((Al-Fe)PILC/H{sub 2}O{sub 2}) system, for more than 2 h, resulted in higher methane production. Both untreated OMW as well as 2-h pre-treated OMW revealed as toxic to anaerobic bacteria.

  14. Synthesis of Polyhydroxyalkanoate in the Peroxisome of Saccharomyces cerevisiae by Using Intermediates of Fatty Acid β-Oxidation

    OpenAIRE

    Poirier, Yves; Erard, Nadine; Petétot, Jean MacDonald-Comber

    2001-01-01

    Medium-chain-length polyhydroxyalkanoates (PHAs) are polyesters having properties of biodegradable thermoplastics and elastomers that are naturally produced by a variety of pseudomonads. Saccharomyces cerevisiae was transformed with the Pseudomonas aeruginosa PHAC1 synthase modified for peroxisome targeting by the addition of the carboxyl 34 amino acids from the Brassica napus isocitrate lyase. The PHAC1 gene was put under the control of the promoter of the catalase A gene. PHA synthase expre...

  15. Effects of immature cashew nut-shell liquid (Anacardium occidentale) against oxidative damage in Saccharomyces cerevisiae and inhibition of acetylcholinesterase activity.

    Science.gov (United States)

    De Lima, S G; Feitosa, C M; Citó, A M G L; Moita Neto, J M; Lopes, J A D; Leite, A S; Brito, M C; Dantas, S M M; Cavalcante, A A C Melo

    2008-01-01

    The cashew tree (Anacardium occidentale) represents one of the major cheapest sources of non-isoprenoid phenolic lipids, which have a variety of biological properties: they can act as molluscicides, insecticides, fungicides, have anti-termite properties, have medicinal applications, and demonstrate antioxidant activity in vitro. Immature cashew nut-shell liquid (iCNSL) is a unique natural source of unsaturated long-chain phenols. Their use has stimulated much research in order to prepare drug analogues for application in several fields. The objective of the present study was to determine whether iCNSL has antioxidant properties when used in strains of the yeast Saccharomyces cerevisiae and to measure the inhibitory activity of acetylcholinesterase. The constituents were identified using thin-layer chromatography, gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy, and (1)H and (13)C nuclear magnetic resonance. The iCNSL contains anacardic acid, cardanol, cardol, and 2-methyl cardol. Immature cashew nut oil contains triacylglycerols, fatty acids, alkyl-substituted phenols, and cholesterol. The main constituents of the free fatty acids are palmitic (C(16:0)) and oleic acid (C(18:1)). iCNSL has excellent protective activities in strains of S. cerevisiae against oxidative damage induced by hydrogen peroxide and inhibits acetylcholinesterase activity. iCNSL may have an important role in protecting DNA against damage induced by reactive oxygen species, as well as hydrogen peroxide, generated by intra- and extracellular mechanisms. PMID:18949700

  16. Wet oxidation of EDTA using metal-doped MCM-41 as catalyst

    International Nuclear Information System (INIS)

    Decontaminants like ethylenediaminetetraacetic acid (EDTA), ascorbic acid, and citric acid are widely used in the radioactive decontamination of reactor components. The complexants interfere in the treatment of radioactive effluent and hence it is imperative to oxidatively destroy the complexant to enable easy treatment of radioactive effluent. An attempt has been made to oxidatively destroy EDTA using hydrogen peroxide as oxidant in the presence of metal-doped MCM-41A as catalyst. The reason for using metal-doped MCM-41 as catalyst for the oxidative degradation is because of its larger surface area (∝ 1 000 m2 . g-1) with small pore size (20-100 Aa). Also the metal used has variable valency, which helps in undergoing electron transfer reactions. Metal-doped MCM-41 was synthesized. Results indicate that among the metals chosen for doping MCM-41, the catalytic efficiency in the oxidative degradation decreased in the following order: molybdenum > vanadium > titanium. (orig.)

  17. Catalytic Wet Air Oxidation of o-Chlorophenol in Wastewater%邻氯苯酚废水的催化湿式氧化处理

    Institute of Scientific and Technical Information of China (English)

    徐新华; 汪大翚

    2003-01-01

    Catalytic wet air oxidation (CWAO) was investigated in laboratory-scale experiments for the treatmentof o-chlorophenol in wastewater. Experimental results showed that wet air oxidation (WAO) process in the absence ofcatalyst was also effective for o-chlorophenol in wastewater treatment. Up to 80% of the initial CODCr was removedby wet air oxidation at 270℃ with twice amount of the required stoichiometric oxygen supply. At temperatureof 150℃, the removal rate of CODCr was only 30%. Fe2(SO4)3, CuSO4, Cu(NO3)2 and MnSO4 exhibited highcatalytic activity. Higher removal rate of CODCr was obtained by CWAO. More than 96% of the initial CODCrwas removed at 270℃ and 84.6%-93.6% of the initial CODCr was removed at 150℃. Mixed catalysts had bettercatalytic activity for the degradation of o-chlorophenol in wastewater.

  18. Disrupted short chain specific β-oxidation and improved synthase expression increase synthesis of short chain fatty acids in Saccharomyces cerevisiae.

    Science.gov (United States)

    Leber, Christopher; Choi, Jin Wook; Polson, Brian; Da Silva, Nancy A

    2016-04-01

    Biologically derived fatty acids have gained tremendous interest as an alternative to petroleum-derived fuels and chemical precursors. We previously demonstrated the synthesis of short chain fatty acids in Saccharomyces cerevisiae by introduction of the Homo sapiens fatty acid synthase (hFAS) with heterologous phosphopantetheine transferases and heterologous thioesterases. In this study, short chain fatty acid production was improved by combining a variety of novel enzyme and metabolic engineering strategies. The use of a H. sapiens-derived thioesterase and phosphopantetheine transferase were evaluated. In addition, strains were engineered to disrupt either the full β-oxidation (by deleting FAA2, PXA1, and POX1) or short chain-specific β-oxidation (by deleting FAA2, ANT1, and PEX11) pathways. Prohibiting full β-oxidation increased hexanoic and octanoic acid levels by 8- and 79-fold relative to the parent strain expressing hFAS. However, by targeting only short chain β-oxidation, hexanoic and octanoic acid levels increased further to 31- and 140-fold over the parent. In addition, an optimized hFAS gene increased hexanoic, octanoic, decanoic and total short chain fatty acid levels by 2.9-, 2.0-, 2.3-, and 2.2-fold, respectively, relative to the non-optimized counterpart. By combining these unique enzyme and metabolic engineering strategies, octanoic acid was increased more than 181-fold over the parent strain expressing hFAS. PMID:26388428

  19. Microstructure and properties of tungsten–samarium oxide composite prepared by a novel wet chemical method and spark plasma sintering

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • W–Sm2O3 powders were synthesized by a novel wet chemical method. • Oxide particles were distributed in both the tungsten grains and grain boundaries. • Tensile strength of W–Sm2O3 samples was higher than those of pure W samples. - Abstract: W–1 wt% Sm2O3 powders doped with highly uniform Sm2O3 were successfully synthesized by a novel wet chemical method followed by hydrogen reduction. The powders were consolidated by spark plasma sintering (SPS) at 1800 °C to suppress grain growth during sintering. The FE-SEM and HRTEM analysis, tensile test and thermal conductivity measurements were used to characterize these samples. The grain size, relative density of the bulk samples fabricated by SPS sintering were 4 μm and 97.8%, respectively. The tensile strength values of Sm2O3/W samples were higher than those of pure W samples. As the temperature rises from 25 to 800 °C, the thermal conductivity of pure W and W–1 wt% Sm2O3 composites decreased with the same trend and the thermal conductivity of both samples was above 160 W/m K at room temperature

  20. Fabrication and characterization of ZnO nanowires by wet oxidation of Zn thin film deposited on Teflon substrate

    Science.gov (United States)

    Farhat, O. F.; Halim, M. M.; Abdullah, M. J.; Ali, M. K. M.; Ahmed, Naser M.; Bououdina, M.

    2015-10-01

    In this study, ZnO nanowires (NWs) were successfully grown for the first time on to Teflon substrate by a wet oxidation of a Zn thin film coated by RF sputtering technique. The sputtered Zn thin film was oxidized at 100 °C for 5 h under water-vapour using a horizontal furnace. This oxidation process transformed Zn thin film into ZnO with wire-like nanostructure. XRD analysis confirms the formation of single nanocrystalline ZnO phase having a low compressive strain. FESEM observations reveal high density of ZnO NWs with diameter ranging from 34 to 52 nm and length about 2.231 μm, which are well distributed in different direction. A flexible ZnO NWs-based metal-semiconductor-metal UV photodetector was fabricated. Photo-response and sensitivity measurements under low power illumination (375 nm, 1.5 mW/cm2) showed a high sensitivity of 2050%, which can be considered a relatively fast response and baseline recovery for UV detection.

  1. Energy balance and cost-benefit analysis of biogas production from perennial energy crops pretreated by wet oxidation

    DEFF Research Database (Denmark)

    Uellendahl, Hinrich; Wang, Guangtao; Møller, H.B.;

    2008-01-01

    Perennial crops need far less energy to plant, require less fertilizer and pesticides, and show a lower negative environmental impact compared with annual crops like for example corn. This makes the cultivation of perennial crops as energy crops more sustainable than the use of annual crops. The...... conversion into biogas in anaerobic digestion plants shows however much lower specific methane yields for the raw perennial crops like miscanthus and willow due to their lignocellulosic structure. Without pretreatment the net energy gain is therefore lower for the perennials than for corn. When applying wet...... oxidation to the perennial crops, however, the specific methane yield increases significantly and the ratio of energy output to input and of costs to benefit for the whole chain of biomass supply and conversion into biogas becomes higher than for corn. This will make the use of perennial crops as energy...

  2. Development of the Monolith Froth Reactor for Catalytic Wet Oxidation of CELSS Model Wastes

    Science.gov (United States)

    Abraham, Martin; Fisher, John W.

    1995-01-01

    The aqueous phase oxidation of acetic acid, used as a model compound for the treatment of CELSS (Controlled Ecological Life Support System) waste, was carried out in the monolith froth reactor which utilizes two-phase flow in the monolith channels. The catalytic oxidation of acetic acid was carried out over a Pt/Al2O3 catalyst, prepared at The University of Tulsa, at temperatures and pressures below the critical point of water. The effect of externally controllable parameters (temperature, liquid flow rate, distributor plate orifice size, pitch, and catalyst distance from the distributor plate) on the rate of acetic acid oxidation was investigated. Results indicate reaction rate increased with increasing temperature and exhibited a maximum with respect to liquid flow rate. The apparent activation energy calculated from reaction rate data was 99.7 kJ/mol. This value is similar to values reported for the oxidation of acetic acid in other systems and is comparable to intrinsic values calculated for oxidation reactions. The kinetic data were modeled using simple power law kinetics. The effect of "froth" feed system characteristics was also investigated. Results indicate that the reaction rate exhibits a maximum with respect to distributor plate orifice size, pitch, and catalyst distance from the distributor plate. Fundamental results obtained were used to extrapolate where the complete removal of acetic acid would be obtained and for the design and operation of a full scale CELSS treatment system.

  3. Hydrolysis of solubilized hemicellulose derived from wet-oxidized wheat straw by a mixture of commercial fungal enzyme preparations

    Energy Technology Data Exchange (ETDEWEB)

    Skammelsen Schmidt, Anette; Thomsen, Alle Belinda; Woidemann, Anders [Risoe National Lab. (Denmark); Tenkanen, Maija [VTT Biotechnology and Food Research (Finland)

    1998-04-01

    The enzymatic hydrolysis of the solubilized hemicellulose fraction from wet-oxidized wheat straw was investigated for quantification purposes. An optimal hydrolysis depends on factors such as composition of the applied enzyme mixture and the hydrolysis conditions (enzyme loading, hydrolysis time, pH-value, and temperature). A concentrated enzyme mixture was used in this study prepared at VTT Biotechnology and Food Research, Finland, by mixing four commercial enzyme preparations. No distinctive pH-value and temperature optima were identified after a prolonged incubation of 24 hours. By reducing the hydrolysis time to 2 hours a temperature optimum was found at 50 deg. C, where a pH-value higher than 5.2 resulted in reduced activity. An enzyme-substrate-volume-ratio of 0.042, a pH-value of 5.0, and a temperature of 50 deg. C were chosen as the best hydrolysis conditions due to an improved monosaccharide yield. The hydrolysis time was chosen to be 24 hours to ensure equilibrium and total quantification. Even under the best hydrolysis conditions, the overall sugar yield from the enzymatic hydrolysis was only 85% of that of the optimal acid hydrolysis. The glucose yield were approximately the same for the two types of hydrolyses, probably due to the high cellulase activity in the VTT-enzyme mixture. For xylose and arabinose the enzymatic hydrolysis yielded only 80% of that of the acid hydrolysis. As the pentoses existed mainly as complex polymers their degradation required many different enzymes, some of which might be missing from the VTT-enzyme mixture. Furthermore, the removal of side-choins from the xylan backbone during the wet-oxidation pretreatment process might enable the hemicellulosic polymers to interact and precipitate, hence, reducing the enzymatic digestibility of the hemicellulose. (au) 8 tabs., 10 ills., 65 refs.

  4. Fe-Al-Pillared Clays: Catalysts for Wet Peroxide Oxidation of Phenol

    Science.gov (United States)

    Guélou, Erwan; Tatibouët, Jean-Michel; Barrault, Joël

    Catalytic phenol oxidation with hydrogen peroxide (CWPO) was performed over iron containing clays, pillared with Al or mixed Fe-Al complexes. This study deals with the better conditions for the oxidation reaction (temperature, pH, hydrogen peroxide concentration, atmosphere, etc.) in the presence of homogeneous or heterogeneous catalysts. The reaction was performed in a dynamic fixed-bed reactor, which gave the effect of the main experimental variables and an estimation of the kinetic parameters. The catalysts were characterized by classical techniques and by electron spin resonance (ESR). From ESR experiments the reaction mechanism involving hydroxyl radicals was also investigated.

  5. Wet carbon-based solid acid/potassium permanganate as an efficient heterogeneous reagents for oxidation of alcohols under mild conditions

    Institute of Scientific and Technical Information of China (English)

    Arash Shokrolahi; Abbas Zali; Mohammad Hossein Kes

    2008-01-01

    Wet carbon-based solid acid and potassium permanganate were used as new reagents for oxidation of alcohols to their corresponding aldehydes and ketones in heterogeneous mixtures.The experiments were done moderately at mild condition and high yields in suitable times were obtained.

  6. Potential inhibitors from wet oxidation of wheat straw and their effect on growth and ethanol production by ¤Thermoanaerobacter mathranii¤

    DEFF Research Database (Denmark)

    Klinke, H.B.; Thomsen, A.B.; Ahring, B.K.

    2001-01-01

    Alkaline wet oxidation (WO) (using water, 6.5 g/l sodium carbonate, and 12 bar oxygen at 195 degreesC) was used for pre-treating wheat straw (60 g/l), resulting in a hemicellulose-rich hydrolysate and a cellulose-rich solid fraction. The hydrolysate consisted of soluble hemicellulose (9 g/l), ali...

  7. Controlled preparation of carbon nanotube-iron oxide nanoparticle hybrid materials by a modified wet impregnation method

    Energy Technology Data Exchange (ETDEWEB)

    Tsoufis, Theodoros, E-mail: ttsoufis@cc.uoi.gr [University of Ioannina, Department of Materials Science and Engineering (Greece); Douvalis, Alexios P. [University of Ioannina, Physics Department (Greece); Lekka, Christina E. [University of Ioannina, Department of Materials Science and Engineering (Greece); Trikalitis, Pantelis N. [University of Crete, Department of Chemistry (Greece); Bakas, Thomas [University of Ioannina, Physics Department (Greece); Gournis, Dimitrios [University of Ioannina, Department of Materials Science and Engineering (Greece)

    2013-09-15

    We report a novel, simple, versatile, and reproducible approach for the in situ synthesis of iron oxide nanoparticles (NP) on the surface of carbon nanotubes (CNT). Chemically functionalized single- or multi-wall CNT were used as nanotemplates for the synthesis of a range of very small (<10 nm) ferrimagnetic and/or anti-ferromagnetic iron oxide NP on their surface. For the synthesis of the hybrid materials, we employed for the first time a modified wet impregnation method involving the adsorption of ferric cations (as nanoparticle's precursor) on the functionalized nanotube surface and the subsequent interaction with acetic acid vapors followed by calcination at 400 Degree-Sign C under different atmospheres (air, argon, and oxygen). X-ray diffraction, transmission electron microscopy, Moessbauer spectroscopy, and magnetization measurements were used to study in-detail the morphology, size, and type of crystalline phases in the resulting hybrid materials. In addition, Raman measurements were used to monitor possible structural changes of the nanotubes during the synthetic approach. The experimental results were further supported by density functional theory calculations. These calculations were also used to disclose, how the type of the carbon nanotube template affects the nature and the size of the resulting NP in the final hybrids.

  8. CATALYTIC WET PEROXIDE OXIDATION OF HYDROQUINONE WITH Co(II)/ACTIVE CARBON CATALYST LOADED IN STATIC BED

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Catalysts based on Co(II) supported on active carbon were prepared and loaded in static bed. The hydroquinone would be degraded completely after treated by Catalytic wet peroxide oxidation method with Co(II)/active carbon catalyst. After activate treatment, the active carbon was immerged in cobaltous nitrate solution, then put into a drying oven, Co(II) could be loaded on the micro-surface of carbon. Taking the static bed as the equipment, the absorption of active carbon and catalysis of Co(II) was used to reduce activation energy of hydroquinone. Thus hydroquinone could be drastically degraded and the effluent can be drained under the standard. Referring to Fenton reaction mechanism, experiment had been done to study the heterogeneous catalyzed oxidation mechanism of Co(II). The degradation rate of hydroquinone effluent could be achieved to 92% when treated in four columns at H2O2 concentration 10%, reaction temperature 40℃ , pH 5 and reaction time 2.5h.

  9. CATALYTIC WET PEROXIDE OXIDATION OF HYDROQUINONE WITH Co(Ⅱ)/ACTIVE CARBON CATALYST LOADED IN STATIC BED

    Institute of Scientific and Technical Information of China (English)

    LI Chunxiang; YAN Yongsheng; XU Wanzhen

    2008-01-01

    Catalysts based on Co(Ⅱ) supported on active carbon were prepared and loaded in static bed.The hydroquinone wouid be degraded completely after treated by Catalytic wet peroxide oxidation method with Co(Ⅱ)/active carbon catalyst.After activate treatment, the active carbon was immerged in cobaltoas nitrate solution, then put into a drying oven, Co(Ⅱ) could be loaded on the micro-surface of carbon.Taking the static bed as the equipment, the absorption of active carbon and catalysis of Co(Ⅱ) was used to reduce activation energy of hydroquinone.Thus hydroquinone could be drastically degraded and the effluent can be drained under the standard.Referring to Fenton reaction mechanism, experiment had been done to study the heterogeneous catalyzed oxidation mechanism of Co(Ⅱ).The degradation rate of hydroquinone effluent could be achieved to 92% when treated in four columns at H2O2 concentration 10%, reaction temperature 40℃, pH 5 and reaction time 2.5h.

  10. A study of the wet chemical oxidation and solidification of radioactive spent ion exchange resins

    International Nuclear Information System (INIS)

    This paper describes the research works on the decomposition of Ion-Exchange Resins (IERs) in H2O2-Fe2+/Cu2+ catalysis systems for volume reduction and improvement of immobilization in cement. The resins used in the study were polystyrene strong acidic and basic resins containing about 45% of water. The radioactive spent resins loading 60Co, 137Cs, 134Cs, 90Sr and 51Cr with a radioactive activity level of 4GBq/m3 were obtained from a reactor installation. It has been found in batch scale experiment that many factors has influence on the decomposition of IERs, and the most important ones are H2O2 dosage, H2O2 dose rate, temperature and pH value. The best temperature range is 97-99 deg. C. The pH-value of resin slurry chosen in this study is 2.0-3.0. The appropriate dosage of H2O2(30% vol.) is 200 ml/25 g wet mixed resins. The decomposition ratio is 100% and more than 90% for cation and anion IERs respectively, while it is 85% for mixed resins (as TOC-value). The analytical results indicates that the radioactive nuclides loaded in the spent resins are concentrated in decomposition solution and solid residues. No radioactivity enters into the off-gas, while the condensate from the reaction system has a radioactive activity of 1.65 Bq/l. Foaming is a problem associated with resin dissolution. Addition of a little amount of anti-foam agent can solve this problem very well. Three cementation materials have been chosen for encapsulation of decomposition residue. All of the tree kind of solidification materials can produce qualified cemented products with excellent properties for long term storage. The adopted volume reduction (VR) process can significantly reduce waste volume of solidified product decreases by 40% compared with that of original spent resin. (author). 4 refs, 2 figs, 2 tabs

  11. Temperature Induced Wetting and Dewetting Effects of Dioctylbenzothieno-benzothiophene on Silicon Oxide Surfaces

    International Nuclear Information System (INIS)

    Full text: The excellent performance of the molecule dioctyl-benzothieno-benzothiophene (C8-BTBT) in organic thin film transistors is strongly influenced by heat treatment. Spin coating of the film at elevated temperatures (within the liquid-crystalline state), leads to an increase in charge carrier mobilities up to 3 cm2/V s. The structural properties of C8-BTBT thin films are investigated as a function of temperature in terms of crystallographic properties and morphology. Spatially resolved microscopic methods (AFM and optical microscopy) as well as integral characterisation methods (Grazing incidence x-ray scattering, x-ray reflectivity) are used. The disordered monolayer film (thickness 2.4 nm) remains unstable after the spin coating process. With increasing temperatures, dewetting of the monolayer is observed by the formation of crystalline islands with an average height of about 15 nm. Approaching the transition temperature to the smectic state, at a temperature of 900C, re-wetting is observed and a monolayer is formed on the substrate surface. This monolayer (thickness 2.9 nm) remains stable in the liquid crystalline state as well as after cooling back to room temperature. Also multilayer films show pronounced dewetting during heating by the formation of huge crystalline islands with a lateral size in the μm range. At 1050C a monolayer (thickness 2.9 nm), at 1080C a bilayer and at 1150C a triple layer has developed. Decreasing temperatures reveal the reversibility of the layer-by-layer formation. All found layered structures can be stabilized by rapid cooling. (author)

  12. Oxidative stripping process for the recovery of uranium from wet-process phosphoric acid

    International Nuclear Information System (INIS)

    The present invention is a two-cycle liquid-liquid extraction process in which the uranium, as uranous ion, is extracted with a first-cycle extractant and then oxidatively stripped with a concentrated phosphoric acid solution. This uranium-enriched strip solution then serves as feed for a second liquid-liquid solvent extraction cycle where uranyl ions are extracted into an organic phase, stripped from the organic phase with ammonium carbonate soluton, and recovered as a high-grade u3O8 product. (author)

  13. Cermet sintering on the oase of molybdenum, nickel, aluminium oxide in dry and wet hydrogen medium

    International Nuclear Information System (INIS)

    Cermet sintering on the base of molybdenum, nickel and aluminium oxide in dry and wer hydrogen medium is studied. It is stated that presence of water vapours permits to decrease sintering temperature of molybdenum containing cermets and to prepare dense nickeliferous cermets. Cermet density can he rather high at final stages of sintering that is probably conditioned by decrease of growth rate of corundum crystals. Pressing pressure activates cermet siptering at intermediate stages and it is low effective at finite stages of condensation. Constancy of relative reduction of void volume is preserved only at final stages of sintering

  14. Large-Scale Mercury Control Technology Testing for Lignite-Fired Utilities - Oxidation Systems for Wet FGD

    Energy Technology Data Exchange (ETDEWEB)

    Steven A. Benson; Michael J. Holmes; Donald P. McCollor; Jill M. Mackenzie; Charlene R. Crocker; Lingbu Kong; Kevin C. Galbreath

    2007-03-31

    Mercury (Hg) control technologies were evaluated at Minnkota Power Cooperative's Milton R. Young (MRY) Station Unit 2, a 450-MW lignite-fired cyclone unit near Center, North Dakota, and TXU Energy's Monticello Steam Electric Station (MoSES) Unit 3, a 793-MW lignite--Powder River Basin (PRB) subbituminous coal-fired unit near Mt. Pleasant, Texas. A cold-side electrostatic precipitator (ESP) and wet flue gas desulfurization (FGD) scrubber are used at MRY and MoSES for controlling particulate and sulfur dioxide (SO{sub 2}) emissions, respectively. Several approaches for significantly and cost-effectively oxidizing elemental mercury (Hg{sup 0}) in lignite combustion flue gases, followed by capture in an ESP and/or FGD scrubber were evaluated. The project team involved in performing the technical aspects of the project included Babcock & Wilcox, the Energy & Environmental Research Center (EERC), the Electric Power Research Institute, and URS Corporation. Calcium bromide (CaBr{sub 2}), calcium chloride (CaCl{sub 2}), magnesium chloride (MgCl{sub 2}), and a proprietary sorbent enhancement additive (SEA), hereafter referred to as SEA2, were added to the lignite feeds to enhance Hg capture in the ESP and/or wet FGD. In addition, powdered activated carbon (PAC) was injected upstream of the ESP at MRY Unit 2. The work involved establishing Hg concentrations and removal rates across existing ESP and FGD units, determining costs associated with a given Hg removal efficiency, quantifying the balance-of-plant impacts of the control technologies, and facilitating technology commercialization. The primary project goal was to achieve ESP-FGD Hg removal efficiencies of {ge}55% at MRY and MoSES for about a month.

  15. Wet thermal annealing effect on TaN/HfO2/Ge metal-oxide-semiconductor capacitors with and without a GeO2 passivation layer

    Institute of Scientific and Technical Information of China (English)

    Liu Guan-Zhou; Chen Song-Yan; Li Cheng; Lu Chang-Bao; Tang Rui-Fan; Tang Meng-Rao; Wu Zheng; Yang Xu; Huang Wei; Lai Hong-Kai

    2012-01-01

    Wet thermal annealing effects on the properties of TaN/HfO2/Ge metal-oxide-semiconductor (MOS) structures with and without a GeO2 passivation layer are investigated.The physical and the electrical properties are characterized by X-ray photoemission spectroscopy,high-resolution transmission electron microscopy,capacitane-voltage (C V) and current-voltage characteristics.It is demonstrated that wet thermal annealing at relatively higher temperature such as 550 °C can lead to Ge incorporation in HfO2 and the partial crystallization of HfO2,which should be responsible for the serious degradation of the electrical characteristics of the TaN/HfO2/Ge MOS capacitors.However,wet thermal annealing at 400°C can decrease the GeOx interlayer thickness at the HfO2/Ge interface,resulting in a significant reduction of the interface states and a smaller effective oxide thickness,along with the introduction of a positive charge in the dielectrics due to the hydrolyzable property of GeOx in the wet ambient.The pre-growth of a thin GeO2 passivation layer can effectively suppress the interface states and improve the C-V characteristics for the as-prepared HfO2 gated Ge MOS capacitors,but it also dissembles the benefits of wet thermal annealing to a certain extent.

  16. Enzymatic recognition of DNA damage induced by UVB-photosensitized titanium dioxide and biological consequences in Saccharomyces cerevisiae: Evidence for oxidatively DNA damage generation

    International Nuclear Information System (INIS)

    Although titanium dioxide (TiO2) has been considered to be biologically inert, finding use in cosmetics, paints and food colorants, recent reports have demonstrated that when TiO2 is attained by UVA radiation oxidative genotoxic and cytotoxic effects are observed in living cells. However, data concerning TiO2-UVB association is poor, even if UVB radiation represents a major environmental carcinogen. Herein, we investigated DNA damage, repair and mutagenesis induced by TiO2 associated with UVB irradiation in vitro and in vivo using Saccharomyces cerevisiae model. It was found that TiO2 plus UVB treatment in plasmid pUC18 generated, in addition to cyclobutane pyrimidine dimers (CPDs), specific damage to guanine residues, such as 8-oxo-7,8-dihydroguanine (8-oxoG) and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG), which are characteristic oxidatively generated lesions. In vivo experiments showed that, although the presence of TiO2 protects yeast cells from UVB cytotoxicity, high mutation frequencies are observed in the wild-type (WT) and in an ogg1 strain (deficient in 8-oxoG and FapyG repair). Indeed, after TiO2 plus UVB treatment, induced mutagenesis was drastically enhanced in ogg1 cells, indicating that mutagenic DNA lesions are repaired by the Ogg1 protein. This effect could be attenuated by the presence of metallic ion chelators: neocuproine or dipyridyl, which partially block oxidatively generated damage occurring via Fenton reactions. Altogether, the results indicate that TiO2 plus UVB potentates UVB oxidatively generated damage to DNA, possibly via Fenton reactions involving the production of DNA base damage, such as 8-oxo-7,8-dihydroguanine.

  17. Enzymatic recognition of DNA damage induced by UVB-photosensitized titanium dioxide and biological consequences in Saccharomyces cerevisiae: Evidence for oxidatively DNA damage generation

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, A. Viviana, E-mail: alicia.pinto@incqs.fiocruz.br [Laboratorio de Diagnostico Molecular e Hematologia, Faculdade de Farmacia, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21941-540, Rio de Janeiro (Brazil); Laboratorio de Radiobiologia Molecular, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21949-900, Rio de Janeiro (Brazil); Deodato, Elder L. [Laboratorio de Diagnostico Molecular e Hematologia, Faculdade de Farmacia, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21941-540, Rio de Janeiro (Brazil); Laboratorio de Radiobiologia Molecular, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21949-900, Rio de Janeiro (Brazil); Cardoso, Janine S. [Laboratorio de Radiobiologia Molecular, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21949-900, Rio de Janeiro (Brazil); Oliveira, Eliza F.; Machado, Sergio L.; Toma, Helena K. [Laboratorio de Diagnostico Molecular e Hematologia, Faculdade de Farmacia, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21941-540, Rio de Janeiro (Brazil); Leitao, Alvaro C. [Laboratorio de Radiobiologia Molecular, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21949-900, Rio de Janeiro (Brazil); Padula, Marcelo de [Laboratorio de Diagnostico Molecular e Hematologia, Faculdade de Farmacia, Universidade Federal do Rio de Janeiro, Centro de Ciencias da Saude - Ilha do Fundao, CEP 21941-540, Rio de Janeiro (Brazil)

    2010-06-01

    Although titanium dioxide (TiO{sub 2}) has been considered to be biologically inert, finding use in cosmetics, paints and food colorants, recent reports have demonstrated that when TiO{sub 2} is attained by UVA radiation oxidative genotoxic and cytotoxic effects are observed in living cells. However, data concerning TiO{sub 2}-UVB association is poor, even if UVB radiation represents a major environmental carcinogen. Herein, we investigated DNA damage, repair and mutagenesis induced by TiO{sub 2} associated with UVB irradiation in vitro and in vivo using Saccharomyces cerevisiae model. It was found that TiO{sub 2} plus UVB treatment in plasmid pUC18 generated, in addition to cyclobutane pyrimidine dimers (CPDs), specific damage to guanine residues, such as 8-oxo-7,8-dihydroguanine (8-oxoG) and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG), which are characteristic oxidatively generated lesions. In vivo experiments showed that, although the presence of TiO{sub 2} protects yeast cells from UVB cytotoxicity, high mutation frequencies are observed in the wild-type (WT) and in an ogg1 strain (deficient in 8-oxoG and FapyG repair). Indeed, after TiO{sub 2} plus UVB treatment, induced mutagenesis was drastically enhanced in ogg1 cells, indicating that mutagenic DNA lesions are repaired by the Ogg1 protein. This effect could be attenuated by the presence of metallic ion chelators: neocuproine or dipyridyl, which partially block oxidatively generated damage occurring via Fenton reactions. Altogether, the results indicate that TiO{sub 2} plus UVB potentates UVB oxidatively generated damage to DNA, possibly via Fenton reactions involving the production of DNA base damage, such as 8-oxo-7,8-dihydroguanine.

  18. Engineering development and demonstration of DETOX{sup SM} wet oxidation for mixed waste treatment

    Energy Technology Data Exchange (ETDEWEB)

    Dhooge, P.M.; Goldblatt, S.D.; Moslander, J.E.; Robertson, D.T.; Rogers, T.W.; Zigmond, J.A.

    1997-12-01

    DETOX{sup SM}, a catalyzed chemical oxidation process, is under development for treatment of hazardous and mixed wastes at Department of Energy sites. To support this effort, developmental engineering studies have been formed for aspects of the process to help ensure safe and effective operation. Subscale agitation studies have been preformed to identify a suitable mixing head and speed for the primary reaction vessel agitator. Mechanisms for feeding solid waste materials to the primary reaction vessel have been investigated. Filtration to remove solid field process residue, and the use of various filtration aids, has been studied. Extended compatibility studies on the materials of construction have been performed. Due to a change to Rocky Flats Environmental Technology Site (RFETS) for the mixed waste portion of the demonstration, types of wastes suitable and appropriate for treatment at RFETS had to be chosen. A Prototype unit has been fabricated and will be demonstrated on hazardous and mixed wastes at Savannah River Site (SRS) and RFETS during 1997 and 1998. The unit is in shakedown testing at present. Data validation and an engineering evaluation will be performed during the demonstration.

  19. Vertically aligned Mn-doped zinc oxide nanorods by hybrid wet chemical route

    International Nuclear Information System (INIS)

    Mn-doped zinc oxide (Mn:ZnO) nanorods were synthesized by incorporating manganese in aligned ZnO nanorods. For this, Mn was evaporated onto ZnO nanorods and the composite structure was subjected to rapid thermal annealing. The nanorods were preferentially oriented in (0 0 2) direction as indicated by the XRD measurement. Optical band gap was seen to decrease with increasing amount of Mn incorporation. XPS studies indicated that incorporated Mn was in Mn2+ and Mn4+ states. Mn2+ atomic concentration was found to be larger than Mn4+ concentration in all the samples. The Raman spectra of the Mn:ZnO nanorods indicated the presence of the characteristic peak at ∼438 cm-1 for high frequency branch of E2 mode of ZnO. The PL peak at ∼376 nm (∼3.29 eV) was ascribed to the band edge luminescence while the peak at ∼394 nm (∼3.15 eV) was assigned to the donor bound exciton (DoX) and free exciton transition related to Mn2+ states.

  20. Enhancement of dispersion and bonding of graphene-polymer through wet transfer of functionalized graphene oxide

    Directory of Open Access Journals (Sweden)

    F. Sharif

    2012-12-01

    Full Text Available Dispersion of nanomaterials in polymeric matrices plays an important role in determining the final properties of the composites. Dispersion in nano scale, and especially in single layers, provides best opportunity for bonding. In this study, we propose that by proper functionalization and mixing strategy of graphene its dispersion, and bonding to the polymeric matrix can be improved. We then apply this strategy to graphene-epoxy system by amino functionalization of graphene oxide (GO. The process included two phase extraction, and resulted in better dispersion and higher loading of graphene in epoxy matrix. Rheological evaluation of different graphene-epoxy dispersions showed a rheological percolation threshold of 0.2 vol% which is an indication of highly dispersed nanosheets. Observation of the samples by optical microscopy, scanning electron microscopy (SEM, and atomic force microscopy (AFM, showed dispersion homogeneity of the sheets at micro and nano scales. Study of graphene-epoxy composites showed good bonding between graphene and epoxy. Mechanical properties of the samples were consistent with theoretical predictions for ideal composites indicating molecular level dispersion and good bonding between nanosheets and epoxy matrix.

  1. Wet oxidation of glycerol into fine organic acids: catalyst selection and kinetic evaluation

    Directory of Open Access Journals (Sweden)

    J. E. N. Brainer

    2014-12-01

    Full Text Available The liquid phase oxidation of glycerol was performed producing fine organic acids. Catalysts based on Pt, Pd and Bi supported on activated carbon were employed to perform the conversion of glycerol into organic acids at 313 K, 323 K and 333 K, under atmospheric pressure (1.0 bar, in a mechanically agitated slurry reactor (MASR. The experimental results indicated glycerol conversions of 98% with production of glyceric, tartronic and glycolic acids, and dihydroxyacetone. A yield of glyceric acid of 69.8%, and a selectivity of this compound of 70.6% were reached after 4 h of operation. Surface mechanisms were proposed and rate equations were formulated to represent the kinetic behavior of the process. Selective formation of glyceric acid was observed, and the kinetic parameter values indicated the lowest activation energy (38.5 kJ/mol for its production reaction step, and the highest value of the adsorption equilibrium constant of the reactant glycerol (10-4 dm³/mol.

  2. Extraction-wet oxidation process using sulphuric acid for treatment of TBP-dodecane wastes

    International Nuclear Information System (INIS)

    In the nuclear fuel reprocessing plants, 30% n-tributyl phosphate in hydrocarbon diluent is used for extraction of uranium and plutonium from the spent fuel by Purex process. When TBP-dodecane can no longer be purified from its degradation products, it is discarded as alpha bearing, intermediate level wastes containing plutonium and ruthenium-106. To overcome shortcomings of extraction-pyrolysis and saponification processes, studies were undertaken to find the suitability of H2SO4 as an alternative extractant for TBP. Oxidation of TBP to H3PO4 using H2O2 was also explored as H3PO4 can be treated by known procedures for removal of plutonium and ruthenium-106. The experiments were conducted with aged spent solvent wastes discharged from reprocessing plant at Trombay using H2SO4 and H2SO4 - H3PO4 mixture. The decontamination factors (DFs) for alpha activity were found to be satisfactory. The DFs for ruthenium were lower as compared to those obtained in experiments with simulated degraded waste. The gas chromatographic analysis of separated diluent revealed high branched alkane content and low n-dodecane content of separated diluent. It is very much different from that of diluent currently in use. Hence incineration of separated diluent is recommended. (author)

  3. Engineering development and demonstration of DETOXSM wet oxidation for mixed waste treatment

    International Nuclear Information System (INIS)

    DETOXSM, a catalyzed chemical oxidation process, is under development for treatment of hazardous and mixed wastes at Department of Energy sites. To support this effort, developmental engineering studies have been formed for aspects of the process to help ensure safe and effective operation. Subscale agitation studies have been preformed to identify a suitable mixing head and speed for the primary reaction vessel agitator. Mechanisms for feeding solid waste materials to the primary reaction vessel have been investigated. Filtration to remove solid field process residue, and the use of various filtration aids, has been studied. Extended compatibility studies on the materials of construction have been performed. Due to a change to Rocky Flats Environmental Technology Site (RFETS) for the mixed waste portion of the demonstration, types of wastes suitable and appropriate for treatment at RFETS had to be chosen. A Prototype unit has been fabricated and will be demonstrated on hazardous and mixed wastes at Savannah River Site (SRS) and RFETS during 1997 and 1998. The unit is in shakedown testing at present. Data validation and an engineering evaluation will be performed during the demonstration

  4. Preparation and Photocatalytic Activity of Potassium- Incorporated Titanium Oxide Nanostructures Produced by the Wet Corrosion Process Using Various Titanium Alloys

    Directory of Open Access Journals (Sweden)

    So Yoon Lee

    2015-08-01

    Full Text Available Nanostructured potassium-incorporated Ti-based oxides have attracted much attention because the incorporated potassium can influence their structural and physico-chemical properties. With the aim of tuning the structural and physical properties, we have demonstrated the wet corrosion process (WCP as a simple method for nanostructure fabrication using various Ti-based materials, namely Ti–6Al–4V alloy (TAV, Ti–Ni (TN alloy and pure Ti, which have 90%, 50% and 100% initial Ti content, respectively. We have systematically investigated the relationship between the Ti content in the initial metal and the precise condition of WCP to control the structural and physical properties of the resulting nanostructures. The WCP treatment involved various concentrations of KOH solutions. The precise conditions for producing K-incorporated nanostructured titanium oxide films (nTOFs were strongly dependent on the Ti content of the initial metal. Ti and TAV yielded one-dimensional nanowires of K-incorporated nTOFs after treatment with 10 mol/L-KOH solution, whereas TN required a higher concentration (20 mol/L-KOH solution to produce comparable nanostructures. The obtained nanostructures revealed a blue-shift in UV absorption spectra due to the quantum confinement effects. A significant enhancement of the photocatalytic activity was observed via the chromomeric change and the intermediate formation of methylene blue molecules under UV irradiation. This study demonstrates the WCP as a simple, versatile and scalable method for the production of nanostructured K-incorporated nTOFs to be used as high-performance photocatalysts for environmental and energy applications.

  5. Toxicity to Daphnia magna and Vibrio fischeri of Kraft bleach plant effluents treated by catalytic wet-air oxidation.

    Science.gov (United States)

    Pintar, Albin; Besson, Michèle; Gallezot, Pierre; Gibert, Janine; Martin, Dominique

    2004-01-01

    Two Kraft-pulp bleaching effluents from a sequence of treatments which include chlorine dioxide and caustic soda were treated by catalytic wet-air oxidation (CWAO) at T=463 K in trickle-bed and batch-recycle reactors packed with either TiO2 extrudates or Ru(3 wt%)/TiO2 catalyst. Chemical analyses (TOC removal, color, HPLC) and bioassays (48-h and 30-min acute toxicity tests using Daphnia magna and Vibrio fischeri, respectively) were used to get information about the toxicity impact of the starting effluents and of the treated solutions. Under the operating conditions, complex organic compounds are mostly oxidized into carbon dioxide and water, along with short-chain carboxylic acids. Bioassays were found as a complement to chemical analyses for ensuring the toxicological impact on the ecosystem. In spite of a large decrease of TOC, the solutions of end products were all more toxic to Daphnia magna than the starting effluents by factors ranging from 2 to 33. This observation is attributed to the synergistic effects of acetic acid and salts present in the solutions. On the other hand, toxicity reduction with respect to Vibrio fischeri was achieved: detoxification factors greater than unity were measured for end-product solutions treated in the presence of the Ru(3 wt%)/TiO2 catalyst, suggesting the absence of cumulative effect for this bacteria, or a lower sensitivity to the organic acids and salts. Bleach plant effluents treated by the CWAO process over the Ru/TiO2 catalyst were completely biodegradable. PMID:14675640

  6. Wet air oxidation of resorcinol as a model treatment for refractory organics in wastewaters from the wood processing industry.

    Science.gov (United States)

    Weber, Bernd; Chavez, Alma; Morales-Mejia, Julio; Eichenauer, Sabrina; Stadlbauer, Ernst A; Almanza, Rafael

    2015-09-15

    Wastewater treatment systems are important tools to enhance sustainability in terms of reducing environmental impact and complying with sanitary requirements. This work addresses the wet air oxidation (WAO) process for pre-treatment of phenolic wastewater effluents. The aim was to increase biodegradability prior to a subsequent anaerobic stage. In WAO laboratory experiments using a micro-autoclave, the model compound resorcinol was degraded under different oxygen availability regims within the temperature range 150 °C-270 °C. The activation energy was determined to be 51.5 kJ/mol. Analysis of the products revealed that after 3 h of reaction at 230 °C, 97.5% degradation of resorcinol was achieved. At 250 °C and the same reaction time complete removal of resorcinol was observed. In this case the total organic carbon content was reduced down to 29%, from 118.0 mg/L down to 34.4 mg/L. Under these process conditions, the pollutant was only partially mineralized and the ratio of the biological oxygen demand relative to the chemical oxygen demand, which is 0.07 for resorcinol, was increased to a value exceeding 0.5. The main by-product acetic acid, which is a preferred compound for methanogenic bacteria, was found to account for 33% of the total organic carbon. PMID:26164636

  7. Resting Study of Tracer Experiment on Catalytic Wet Oxidation Reactor under Micro-gravity and Earth Gravity Conditions

    Institute of Scientific and Technical Information of China (English)

    YANG Ji; JIA Jin-ping

    2005-01-01

    The International Space Station(ISS) employs catalytic wet oxidation carried out in a Volatile Reactor Assembly (VRA) for water recycling. Previous earth gravity experiments show that the VRA is very effective at removing polar,low molecular weight organics. To compare the reactor performance under micro-gravity and Earth gravity conditions,a tracer study was performed on a space shuttle in 1999 by using 0. 2% potassium carbonate as the chemical tracer.In this paper, the experimental data were analyzed and it is indicated that the reactor can be considered as a plug flow one under both micro-gravity and earth gravity experimental conditions. It has also been proved that dispersion is not important in the VRA reactor under the experimental conditions. Tracer retardation was observed in the experiments and it is most likely caused by catalyst adsorption. It is concluded that the following reasons may also have influence on the retardation of mean residence time: (1) the liquid can be held by appurtenances, which will retard the mean residence time; (2) the pores can hold the tracer, which can also retard the mean residence time.

  8. Thermodynamic study contribution of U-Fe and U-Ga alloys by high temperature mass spectroscopy, and of the wetting of yttrium oxide by uranium

    International Nuclear Information System (INIS)

    High temperature thermodynamic properties study of U-Fe and U-Ga alloys, and wetting study of yttrium oxide by uranium are presented. High temperature mass spectrometry coupled to a Knudsen effusion multi-cell allows to measure iron activity in U-Fe alloys and of gallium in U-Ga alloys, the U activity is deduced from Gibbs-Duhem equation. Wetting of the system U/Y2O3-x is studied between 1413 K and 1973 K by the put drop method visualized by X-rays. This technique also furnishes density, surface tension of U and of U-Fe alloys put on Y2O3-x. A new model of the interfacial oxygen action on wetting is done for the system U/Y2O3-x. (A.B.). 117 refs., figs., tabs

  9. Iron, copper, and manganese complexes with in vitro superoxide dismutase and/or catalase activities that keep Saccharomyces cerevisiae cells alive under severe oxidative stress.

    Science.gov (United States)

    Ribeiro, Thales P; Fernandes, Christiane; Melo, Karen V; Ferreira, Sarah S; Lessa, Josane A; Franco, Roberto W A; Schenk, Gerhard; Pereira, Marcos D; Horn, Adolfo

    2015-03-01

    Due to their aerobic lifestyle, eukaryotic organisms have evolved different strategies to overcome oxidative stress. The recruitment of some specific metalloenzymes such as superoxide dismutases (SODs) and catalases (CATs) is of great importance for eliminating harmful reactive oxygen species (hydrogen peroxide and superoxide anion). Using the ligand HPClNOL {1-[bis(pyridin-2-ylmethyl)amino]-3-chloropropan-2-ol}, we have synthesized three coordination compounds containing iron(III), copper(II), and manganese(II) ions, which are also present in the active site of the above-noted metalloenzymes. These compounds were evaluated as SOD and CAT mimetics. The manganese and iron compounds showed both SOD and CAT activities, while copper showed only SOD activity. The copper and manganese in vitro SOD activities are very similar (IC50~0.4 μmol dm(-3)) and about 70-fold higher than those of iron. The manganese compound showed CAT activity higher than that of the iron species. Analyzing their capacity to protect Saccharomyces cerevisiae cells against oxidative stress (H2O2 and the O2(•-) radical), we observed that all compounds act as antioxidants, increasing the resistance of yeast cells mainly due to a reduction of lipid oxidation. Especially for the iron compound, the data indicate complete protection when wild-type cells were exposed to H2O2 or O2(•-) species. Interestingly, these compounds also compensate for both superoxide dismutase and catalase deficiencies; their antioxidant activity is metal ion dependent, in the order iron(III)>copper(II)>manganese(II). The protection mechanism employed by the complexes proved to be independent of the activation of transcription factors (such as Yap1, Hsf1, Msn2/Msn4) and protein synthesis. There is no direct relation between the in vitro and the in vivo antioxidant activities. PMID:25511255

  10. Catalytic wet peroxide oxidation of aniline in wastewater using copper modified SBA-15 as catalyst.

    Science.gov (United States)

    Kong, Liming; Zhou, Xiang; Yao, Yuan; Jian, Panming; Diao, Guowang

    2016-01-01

    SBA-15 mesoporous molecular sieves modified with copper (Cu-SBA-15) were prepared by pH-adjusting hydrothermal method and characterized by X-ray diffraction, BET, transmission electron microscopy, UV-Vis and (29)Si MAS NMR. The pH of the synthesis gel has a significant effect on the amount and the dispersion of copper on SBA-15. The Cu-SBA-15(4.5) (where 4.5 denotes the pH value of the synthesis gel) modified with highly dispersed copper was used as catalyst for the oxidation of aniline by H2O2. The Cu-SBA-15(4.5) shows a higher catalytic activity compared to CuO on the surface of SBA-15. The influences of reaction conditions, such as initial pH of the aqueous solutions, temperature, as well as the dosages of H2O2 and catalyst were investigated. Under weakly alkaline aqueous solution conditions, the aniline conversion, the H2O2 decomposition and the total organic carbon (TOC) removal could be increased significantly compared to the acid conditions. The percentage of leaching Cu(2+) could be decreased from 45.0% to 3.66% when the initial pH of solution was increased from 5 to 10. The TOC removal could be enhanced with the increases of temperature, H2O2 and catalyst dosage, but the aniline conversion and H2O2 decomposition change slightly with further increasing dosage of catalyst and H2O2. At 343 K and pH 8.0, 100% aniline conversion and 66.9% TOC removal can be achieved under the conditions of 1.0 g/L catalyst and 0.05 mol/L H2O2 after 180 min. Although copper might be slightly leached from catalyst, the homogeneous Cu(2+) contribution to the whole catalytic activity is unimportant, and the highly dispersed copper on SBA-15 plays a dominant role. PMID:26227827

  11. Research on Synergy of Combining Electrochemical Oxidation and Catalytic Wet Oxidation%电场效应与催化湿式氧化协同作用研究

    Institute of Scientific and Technical Information of China (English)

    王华; 李光明; 张芳; 黄菊文

    2009-01-01

    A new catalytic wet oxidation fixed-bed reactor combined with three-dimensional electric-field was developed to investigate catalytic wet oxidation, electrochemical oxidation and electroassisted catalytic wet oxidation of the solution containing phenol in the presence of a catalyst Mn-Sn-Sb-3/γ-Al_2O_3 . Good eleetroassisted catalytic wet oxidation efficiency was obtained in the setup for the combination system even at mild conditions ( T = 130℃, po_2 =1.0 MPa) that the phenol conversion and TOC reduction were up to 94.0% and 88.4% after 27 min treatment, respectively. The result also shows that the rate constants of electroassisted catalytic wet oxidation are much higher than that of not only both catalytic wet oxidation and electrochemical oxidation process alone but also additive efficiencies of catalytic wet oxidation and electrochemical oxidation processes, which indicates an apparent synergetic effect between CWO and ECO processes.%在自行研制开发的一套固定床和复合三维电场一体化连续式催化湿式氧化反应器中,采用浸渍法制备的Mn-Sn-Sb-3/γAl_2O_3催化剂,实验研究了苯酚催化湿式氧化、电催化氧化以及电场效应下的催化湿式氧化过程的行为.结果表明,一体化反应器在较低反应温度(T=130℃)和氧分压(Po_2=1.0 MPa)下即可获得相当满意的处理效果,空时仅为27min时苯酚和TOC的去除率就分别可达到94.0%和88.4%.电场效应下的催化湿式氧化协同降解苯酚的反应速率常数大于单独电催化或催化湿式氧化降解苯酚的反应速率常数,而且还大大超过两者之和,电催化氧化对催化湿式氧化工艺存在明显的协同增效作用.

  12. Short communication: effect of saccharomyces cerevisiae supplementation on some biomarkers of oxidative stress in weaned rabbits during the hot-dry season

    Directory of Open Access Journals (Sweden)

    B.M. Shehu

    2016-03-01

    Full Text Available A feeding trial was conducted to evaluate the effect of Saccharomyces cerevisiae (SC supplementation on some biomarkers of oxidative stress in rabbits during the hot-dry season (temperaturehumidity index: 33.2±0.9oC. Sixty healthy weaned crossbred rabbits, aged between 5-6 wk with live weight of 612.7±60.8 g (mean±standard deviation were used. The rabbits were divided into 5 treatment groups; SC0 receiving a control diet without supplementation of SC, and SC2, SC4, SC6 and SC8 receiving the control diet supplemented with SC at the rate of 2, 4, 6 and 8×109 colony forming units/kg, respectively. The activity of total superoxide dismutase and malonaldehyde in serum were not significantly affected, but serum catalase concentration rose (P<0.05 as the SC inclusion level increased. Although further studies are required, baker’s yeast containing SC could help ameliorate the adverse effects of heat stress in rabbits.

  13. Protection effect of a SiO2 layer in Al0.85Ga0.15As wet oxidation

    Institute of Scientific and Technical Information of China (English)

    Zhou Wenfei; Ye Xiaoling; Xu Bo; Zhang Shizhu; Wang Zhanguo

    2012-01-01

    The Al0.85Ga0.15As layers buried below the GaAs core layer with and without the SiO2 layer were successfully oxidized in a wet ambient environment.The experimental results show that the SiO2 layer has little impact on the lateral-wet-oxidation rate of the Al0.85Ga0.15As layer.The contrast of the SEM image of the oxidized regions and the absence of As-related Raman peaks for samples with the SiO2 layer arise from the removal of As ingredients with the largest atomic number,which leads to improvements in the thermal stability of the oxidized layer.The PL intensities of samples with the SiO2 layer are much stronger than those without the SiO2 layer.The PL emission peak is almost unshifted with a slight broadening under the protection of the SiO2 layer.This is attributed to the SiO2 layer preventing oxidation damage to the GaAs capping layer.

  14. Post-treatment of biologically treated wastewater containing organic contaminants using a sequence of H2O2 based advanced oxidation processes: photolysis and catalytic wet oxidation.

    Science.gov (United States)

    Rueda-Márquez, J J; Sillanpää, M; Pocostales, P; Acevedo, A; Manzano, M A

    2015-03-15

    In this paper the feasibility of a multi-barrier treatment (MBT) for the regeneration of synthetic industrial wastewater (SIWW) was evaluated. Industrial pollutants (orange II, phenol, 4-chlorophenol and phenanthrene) were added to the effluent of municipal wastewater treatment plant. The proposed MBT begins with a microfiltration membrane pretreatment (MF), followed by hydrogen peroxide photolysis (H2O2/UVC) and finishing, as a polishing step, with catalytic wet peroxide oxidation (CWPO) using granular activated carbon (GAC) at ambient conditions. During the microfiltration step (0.7 μm) the decrease of suspended solids concentration, turbidity and Escherichia coli in treated water were 88, 94 and 99%, respectively. Also, the effluent's transmittance (254 nm) was increased by 14.7%. Removal of more than 99.9% of all added pollutants, mineralization of 63% of organic compounds and complete disinfection of total coliforms were reached during the H2O2/UVC treatment step (H2O2:TOC w/w ratio = 5 and an UVC average dose accumulated by wastewater 8.80 WUVC s cm(-2)). The power and efficiency of the lamp, the water transmittance and photoreactor geometry are taken into account and a new equation to estimate the accumulated dose in water is suggested. Remaining organic pollutants with a higher oxidation state of carbon atoms (+0.47) and toxic concentration of residual H2O2 were present in the effluent of the H2O2/UVC process. After 2.3 min of contact time with GAC at CWPO step, 90 and 100% of total organic carbon and residual H2O2 were removed, respectively. Also, the wastewater toxicity was studied using Vibrio fischeri and Sparus aurata larvae. The MBT operational and maintenance costs (O&M) was estimated to be 0.59 € m(-3). PMID:25600300

  15. Improved wetting behavior and thermal conductivity of the three-dimensional nickel foam/epoxy composites with graphene oxide as interfacial modifier

    Science.gov (United States)

    Huang, Liang; Zhu, Pengli; Li, Gang; Sun, Rong

    2016-05-01

    The partial reduced graphene oxide (P-rGO) sheets-wrapped nickel foams (NF@P-rGO) were prepared by hydrothermal method, and then their epoxy composites were fabricated via a simple drop-wetting process. The P-rGO sheets on the metal networks could effectively improve the compatibility between nickel foam and epoxy resin, thus greatly accelerate the wetting of epoxy resin on the foams and avoid cracks in the network-polymer interface. Owing to the existence of high-efficiency conductive metal networks, the NF@P-rGO/epoxy composite has a high thermal conductivity of 0.584 W m-1 K-1, which is 2.6 times higher than that of neat epoxy resin. Additionally, owing to the improved wetting ability, NF@P-rGO-10 wt% boron nitride (BN) microsheets/epoxy composites could be fabricated and have a further higher thermal conductivity of 0.71 W m-1 K-1. We believe the use of P-rGO as a novel surface modifier and the following liquid polymer drop-wetting could be an effective method to obtain novel and outstanding metal foam/polymer composites.

  16. A comparative account of the wet oxidation of cation exchange resin with hydrogen peroxide using titanium, vanadium, and molybdenum doped MCM-41 as catalysts

    International Nuclear Information System (INIS)

    Ion exchange resins are widely used in the nuclear industry for treatment of radioactive waste as well as for the upgrading of heavy water used in the primary heat transport system and moderator system. Repeated usage of the resins calls for replacement and treatment before disposal. The present work involves the application of metal-doped MCM-41 material as a catalyst for the wet oxidation of cation exchange resins using hydrogen peroxide as an oxidizing agent. The sulfate produced from the exchangeable group of the resin reflects the extent of decomposition and the carbonate produced reflects the extent of oxidation of the ion exchange resin. Results indicate that the percentage decomposition and oxidation increase with the weight of the catalyst and the volume of the oxidant, i.e., hydrogen peroxide. As much as 0.5 g of the resin could be decomposed by 12 mL of 30% hydrogen peroxide to 98.7% and oxidized to 99.25% using molybdenum doped MCM-41. Vanadium doped and titanium doped MCM-41 required 14 to 16 mL for complete decomposition and 18 to 20 mL for complete oxidation of the ion exchange resin. (orig.)

  17. Comparing oxidative and dilute acid wet explosion pretreatment of Cocksfoot grass at high dry matter concentration for cellulosic ethanol production

    DEFF Research Database (Denmark)

    Njoku, Stephen Ikechukwu; Uellendahl, Hinrich; Ahring, Birgitte Kiær

    2013-01-01

    investigated for cellulosic ethanol production. The biomass raw materials were pretreated using wet explosion (WEx) at 25% dry matter concentration with addition of oxygen or dilute sulfuric acid. The enzymatic hydrolysis of cellulose was significantly improved after pretreatment. The highest conversion into...

  18. Total catalytic wet oxidation of phenol and its chlorinated derivates with MnO2/CeO2 catalyst in a slurry

    Directory of Open Access Journals (Sweden)

    A. J. Luna

    2009-09-01

    Full Text Available In the present work, a synthetic effluent of phenol was treated by means of a total oxidation process-Catalyzed Wet Oxidation (CWO. A mixed oxide of Mn-Ce (7:3, the catalyst, was synthesized by co-precipitation from an aqueous solution of MnCl2 and CeCl3 in a basic medium. The mixed oxide, MnO2/CeO2, was characterized and used in the oxidation of phenol in a slurry reactor in the temperature range of 80-130ºC and pressure of 2.04-4.76 MPa. A phenol solution containing 2.4-dichlorophenol and 2.4-dichlorophenoxyacetic acid was also degraded with good results. A lumped kinetic model, with two parallel reaction steps, fits precisely with the integrated equation and the experimental data. The kinetic parameters obtained are in agreement with the Arrhenius equation. The activation energies were determined to be 38.4 for the total oxidation and 53.4 kJ/mol for the organic acids formed.

  19. Carbon isotope analysis of dissolved organic carbon in fresh and saline (NaCl) water via continuous flow cavity ring-down spectroscopy following wet chemical oxidation

    Science.gov (United States)

    Conaway, Christopher; Thomas, Randal B.; Saad, Nabil; Thordsen, James J.; Kharaka, Yousif K.

    2015-01-01

    This work examines the performance and limitations of a wet chemical oxidation carbon analyser interfaced with a cavity ring-down spectrometer (WCO-CRDS) in a continuous flow (CF) configuration for measuring δ13C of dissolved organic carbon (δ13C-DOC) in natural water samples. Low-chloride matrix (22.5 µg C/aliquot) may be analysed. The WCO-CRDS approach requires more total carbon (µg C/aliquot) than conventional CF-isotope ratio mass spectrometer, but is nonetheless applicable to a wide range of DOC concentration and water types, including brackish water, produced water, and basinal brines.

  20. Zipping Wetting

    CERN Document Server

    Sbragaglia, Mauro; Pirat, Christophe; Borkent, Bram M; Lammertink, Rob G H; Wessling, Matthias; Lohse, Detlef

    2007-01-01

    Water droplets can completely wet micro-structured superhydrophobic surfaces. The {\\it dynamics} of this rapid process is analyzed by ultra-high-speed imaging. Depending on the scales of the micro-structure, the wetting fronts propagate smoothly and circularly or -- more interestingly -- in a {\\it stepwise} manner, leading to a growing {\\it square-shaped} wetted area: entering a new row perpendicular to the direction of front propagation takes milliseconds, whereas once this has happened, the row itself fills in microseconds ({\\it ``zipping''}). Numerical simulations confirm this view and are in quantitative agreement with the experiments.

  1. Wetting transitions

    International Nuclear Information System (INIS)

    When a liquid droplet is put onto a surface, two situations distinguishable by the contact angle may result. If the contact angle is zero, the droplet spreads across the surface, a situation referred to as complete wetting. On the other hand, if the contact angle is between 0 deg. and 180 deg., the droplet does not spread, a situation called partial wetting. A wetting transition is a surface phase transition from partial wetting to complete wetting. We review the key experimental findings on this transition, together with simple theoretical models that account for the experiments. The wetting transition is generally first order (discontinuous), implying a discontinuity in the first derivative of the surface free energy. In this case, if one measures the thickness of the adsorbed film beside the droplet, at the wetting transition a discontinuous jump in film thickness occurs from a microscopically thin to a thick film. We show that this can lead to the observation of metastable surface states and an accompanying hysteresis. The observed hysteresis poses, in turn, a number of questions concerning the nucleation of wetting films that we also consider here. In addition, we consider the equilibrium wetting film thickness that results from a competition between the long-range van der Waals forces and gravity. Finally, the first-order character of the wetting transition can lead to a similar transition even when the phase that does the wetting is not (yet) stable in the bulk. For such prewetting transitions, a discontinuous thin-to-thick film transition occurs off bulk coexistence. We show that, for the large variety of systems for which prewetting transitions have been observed, the behaviour is surprisingly uniform, and can be mapped onto a simple generic phase diagram. The second part of the review deals with the exceptions to the first-order nature of the wetting transition. Two different types of continuous or critical wetting transition have been reported, for which

  2. Kinetic study of wet oxidation of Si0.5Ge0.5 alloy by Rutherford backscattering spectroscopy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The oxidation of Si0. sGeo.5 alloy has been investigated at the temperatures of 800℃ and 900 ℃. Rutherford backscattering spectroscopy has been employed to determine the composition and thickness of the oxide layers. Only Sio.5Geo. 5O2 layer formed during the oxidation at 800℃, whilst three layers, Si0.5Ge0.5O2, SiO2 and Ge, are existed after the oxidation at 900℃. Experimental results are interpreted by adding a germanium flux F4 in Deal-Grove oxidation model of Silicon.

  3. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory : determination of nonpurgeable suspended organic carbon by wet-chemical oxidation and infrared spectrometry

    Science.gov (United States)

    Burkhardt, Mark R.; Kammer, James A.; Jha, Virendra K.; O'Mara-Lopez, Peggy G.; Woodworth, Mark T.

    1997-01-01

    Precision and accuracy results are described for the determination of nonpurgeable suspended organic carbon (SOC) by silver-filter filtration, wet-chemical oxidation, and infrared determination of hte resulting carbon dioxide (CO2) used at the U.S. Geological Survey's nationalWater Quality Laboratory. An aliquot of raw water isfiltered through a 0.45-micrometer silver filter. The trapped organic material is oxidized using phosphoric acid and potassium persulfate in a scaled glass ampule,and the rseulting CO2 is measured by an infrared CO2 detector. The amount of CO3 is proportional to the concentration of chemically oxidizable nonpurgeable organic carbon in the sample. The SOC method detection limit for routine analysis is 0.2 milligram per liter. The average percent recovery is 97.1 percent and the average standard deviation is 11 percent.

  4. Assessment for development of an industrial wet oxidation system for burning waste and low-grade fuels. Final report, October 18, 1989--February 28, 1995

    International Nuclear Information System (INIS)

    The ultimate goal of this program was to demonstrate safe, reliable, and effective operation of the supercritical water oxidation process (SCWO) at a pilot plant-level throughput. This program was a three phase program. Phase 1 of the program preceded MODEC's participation in the program. MODEC did participate in Phases 2 and 3 of the program. In Phase 2, the target waste and industry were pulp mill sludges from the pulp and paper industry. In Phase 3, the target was modified to be DOE-generated mixed low level waste; wastes containing RCRA hazardous constituents and radionuclide surrogates were used as model wastes. The paper describes the research unit planning and design; bench-scale development of SCWO; research and development of wet oxidation of fuels; and the design of a super-critical water pilot plant

  5. Experimental research on influencing factors of wet removal of NO from coal-fired flue gas by UV/H2O2 advanced oxidation process

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Wet removal of NO from coal-fired flue gas by UV/H2O2 Advanced Oxidation Process (AOP) were investigated in a self-designed UV-bubble reactor. Several main influencing factors (UV intensity, H2O2 initial concentration, initial pH value, solution temperature, NO initial concentration, liquid-gas ratio and O2 percentage content) on the NO removal efficiency were studied. The results showed that UV intensity, H2O2 initial concentration, NO initial concentration and liquid-gas ratio are the main influencing factors. In the best conditions, the highest NO removal efficiency by UV/H2O2 advanced oxidation process could reach 82.9%. Based on the experimental study, the influencing mechanism of the relevant influencing factors were discussed in depth.

  6. Degradation process analysis of the azo dyes by catalytic wet air oxidation with catalyst CuO/γ-Al2O3.

    Science.gov (United States)

    Hua, Li; Ma, Hongrui; Zhang, Lei

    2013-01-01

    Three azo dyes (Methyl Orange, Direct Brown and Direct Green) were treated by catalytic wet air oxidation (CWAO) with the catalysts CuO/γ-Al(2)O(3) prepared by consecutive impregnation. The relationship of decolorization extent, chemical oxygen demand (COD) removal extent and total organic carbon (TOC) in dye solution were investigated. The results indicated that the CuO/γ-Al(2)O(3) catalyst had excellent catalytic activity in treating azo dyes. Almost 99% of color and 70% of TOC were removed in 2h. The high removal extent of color and TOC indicated that the CWAO obtained perfect decomposition for pollutants. The degradation pathway of azo dyes was analyzed by UV-Vis, FTIR and MS. According to the examined results, the hydroxyl ((·)OH) radicals induced strong oxidizing effects in the target solution and destroyed the chromophoric groups of azo-benzene conjugated of the molecular structure. Considering characteristics of the dye structure, the azo bond (-N=N-) would first be attacked by the hydroxyl radical and other free radicals. With the continuous oxidization and the long reaction time at high temperature, these intermediates could be oxidized to the final oxidation products, such as water and carbon dioxide. PMID:22795071

  7. Full scale calcium bromide injection with subsequent mercury oxidation and removal within wet flue gas desulphurization system: Experience at a 700 MW coal-fired power facility

    Science.gov (United States)

    Berry, Mark Simpson

    The Environmental Protection Agency promulgated the Mercury and Air Toxics Standards rule, which requires that existing power plants reduce mercury emissions to meet an emission rate of 1.2 lb/TBtu on a 30-day rolling average and that new plants meet a 0.0002 lb/GWHr emission rate. This translates to mercury removals greater than 90% for existing units and greater than 99% for new units. Current state-of-the-art technology for the control of mercury emissions uses activated carbon injected upstream of a fabric filter, a costly proposition. For example, a fabric filter, if not already available, would require a 200M capital investment for a 700 MW size unit. A lower-cost option involves the injection of activated carbon into an existing cold-side electrostatic precipitator. Both options would incur the cost of activated carbon, upwards of 3M per year. The combination of selective catalytic reduction (SCR) reactors and wet flue gas desulphurization (wet FGD) systems have demonstrated the ability to substantially reduce mercury emissions, especially at units that burn coals containing sufficient halogens. Halogens are necessary for transforming elemental mercury to oxidized mercury, which is water-soluble. Plants burning halogen-deficient coals such as Power River Basin (PRB) coals currently have no alternative but to install activated carbon-based approaches to control mercury emissions. This research consisted of investigating calcium bromide addition onto PRB coal as a method of increasing flue gas halogen concentration. The treated coal was combusted in a 700 MW boiler and the subsequent treated flue gas was introduced into a wet FGD. Short-term parametric and an 83-day longer-term tests were completed to determine the ability of calcium bromine to oxidize mercury and to study the removal of the mercury in a wet FGD. The research goal was to show that calcium bromine addition to PRB coal was a viable approach for meeting the Mercury and Air Toxics Standards rule

  8. Wetting Splashing

    CERN Document Server

    Tsai, Peichun; Dijkstra, Remko; Lohse, Detlef

    2010-01-01

    We present fluid dynamics videos illustrating wetting splashing-produced by water drop impact onto hydrophobic microstructures at high impact velocity ($\\sim 3$ ms$^{-1}$). The substrate consists of regular and transparent microtextures in square or hexagonal lattice, yielding a high contact angle of $\\sim 150 ^\\circ$. Our high speed top-or-bottom view recordings through the transparent surface shed light on the solid-liquid-air interfaces at impact. Despite the superhydrophobicity of the latticed micropillars (of a periodicity of $10 {\\mu}m), water droplet wets a certain central area and moreover entraps an air bubble beneath the droplet. Besides the central wet area, lamella surf on air splashing outward at high impinging velocity. The effects of micropatterns and air pressure on the impact outcome are also examined. We show that microscopic boundary condition, imposed by the solid texture, profoundly influences the macroscopic flow dynamics upon superhydrophobic surfaces at high impinging velocity. In addi...

  9. Wet oxidative method for removal of 2,4,6-trichlorophenol in water using Fe(III), Co(II), Ni(II) supported MCM41 catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Chaliha, Suranjana [Department of Chemistry, Gauhati University, Guwahati 781014, Assam (India); Bhattacharyya, Krishna Gopal [Department of Chemistry, Gauhati University, Guwahati 781014, Assam (India)], E-mail: krishna2604@sify.com

    2008-02-11

    Chlorophenols in water are resistant to biological oxidation and they have to be destroyed by chemical oxidation. In the present work, Fe(III), Co(II) and Ni(II) incorporated MCM41 mesoporous solids were used as catalysts for oxidation of 2,4,6-trichlorophenol in water with or without the oxidant, H{sub 2}O{sub 2}. The catalysts were prepared by impregnation and were characterized by XRD and FTIR measurements. The parent MCM41, Fe(III), Co(II) and Ni(II) impregnated MCM41 had cation exchange capacity of 20.5, 25.5, 24.2, 26.0 mequiv./100 g, respectively. The catalysts were used after calcination at 773-873 K for 5 h. The reactions were carried out in a high pressure stirred reactor at 0.2 MPa (autogenous) and 353 K under various reaction conditions. The conversion achieved with Fe(III), Co(II) and Ni(II) incorporated MCM41 in 5 h is respectively 59.4, 50.0 and 65.6% with 2,4,6-TCP:H{sub 2}O{sub 2} molar ratio of 1:1, and 60.2, 60.9 and 68.8% in absence of H{sub 2}O{sub 2}. The oxidation has a first order rate coefficient of (1.2-4.8) x 10{sup -3} min{sup -1}. The results show that introduction of Fe(III), Co(II) and Ni(II) into MCM-41 through impregnation produces very effective catalysts for wet oxidation of 2,4,6-trichlorophenol.

  10. Wet oxidation of ordered mesoporous carbon FDU-15 by using (NH4)2S2O8 for fast adsorption of Sr(II): An investigation on surface chemistry and adsorption mechanism

    Science.gov (United States)

    Song, Yang; Ye, Gang; Chen, Jing; Lv, Dachao; Wang, Jianchen

    2015-12-01

    Surface modification of ordered mesoporous carbon (OMC) by wet oxidation provides an oxygen-enriched platform for complexation of metal ions. Here, we present a comprehensive study on the surface chemistry and textual property of OMC FDU-15 modified by wet oxidation using (NH4)2S2O8 as a benign oxidant. And, for the first time, the adsorption behavior and mechanism of wet-oxidized OMC FDU-15 toward Sr(II) in aqueous solutions were investigated. The mesostructural regularity of the OMC FDU-15 was well-reserved under wet oxidation. Compared to OMC CMK-type counterparts prepared via nanocasting, the OMC FDU-15 by soft template method showed much-enhanced structural stability. Due to the introduction of abundant oxygen-containing species, the oxidized OMC FDU-15 exhibited excellent hydrophilicity and dispersibility in aqueous solutions. The adsorption behavior toward Sr(II) was fully investigated, showing a super-fast adsorption kinetics (equilibrium) and a Langmuir adsorption isotherm. Moreover, an in-depth X-ray photoelectron spectroscopy analysis through deconvolution of high resolution C1s and O1s spectra was implemented to identify the chemical species of the surface functional groups, while probing the adsorption mechanism. The results suggested that oxygen donor atoms in Csbnd O single bonds mainly contribute to the adsorption of Sr(II) via formation of metal-ligand complexation.

  11. Selective recovery of pure copper nanopowder from indium-tin-oxide etching wastewater by various wet chemical reduction process: Understanding their chemistry and comparisons of sustainable valorization processes.

    Science.gov (United States)

    Swain, Basudev; Mishra, Chinmayee; Hong, Hyun Seon; Cho, Sung-Soo

    2016-05-01

    Sustainable valorization processes for selective recovery of pure copper nanopowder from Indium-Tin-Oxide (ITO) etching wastewater by various wet chemical reduction processes, their chemistry has been investigated and compared. After the indium recovery by solvent extraction from ITO etching wastewater, the same is also an environmental challenge, needs to be treated before disposal. After the indium recovery, ITO etching wastewater contains 6.11kg/m(3) of copper and 1.35kg/m(3) of aluminum, pH of the solution is very low converging to 0 and contain a significant amount of chlorine in the media. In this study, pure copper nanopowder was recovered using various reducing reagents by wet chemical reduction and characterized. Different reducing agents like a metallic, an inorganic acid and an organic acid were used to understand reduction behavior of copper in the presence of aluminum in a strong chloride medium of the ITO etching wastewater. The effect of a polymer surfactant Polyvinylpyrrolidone (PVP), which was included to prevent aggregation, to provide dispersion stability and control the size of copper nanopowder was investigated and compared. The developed copper nanopowder recovery techniques are techno-economical feasible processes for commercial production of copper nanopowder in the range of 100-500nm size from the reported facilities through a one-pot synthesis. By all the process reported pure copper nanopowder can be recovered with>99% efficiency. After the copper recovery, copper concentration in the wastewater reduced to acceptable limit recommended by WHO for wastewater disposal. The process is not only beneficial for recycling of copper, but also helps to address environment challenged posed by ITO etching wastewater. From a complex wastewater, synthesis of pure copper nanopowder using various wet chemical reduction route and their comparison is the novelty of this recovery process. PMID:26918838

  12. Carbon isotopic analysis of dissolved organic carbon in produced water brines by wet chemical oxidation and cavity ring-down spectroscopy

    Science.gov (United States)

    Thomas, B.; Conaway, C.; Kharaka, Y. K.; Saad, N.

    2012-12-01

    We have adapted the Picarro iTOC CRDS isotope analyzer for analysis of produced water brines via wet chemical persulfate oxidation. In particular, we developed strategies and techniques for overcoming the limitation imposed by low oxidation efficiencies due to the chloride ion interference with persulfate oxidation. These techniques are important for understanding the origin of dissolved organic carbon in subsurface fluids from oilfields, as a tracer of fracking fluids in groundwater, and in interpreting changes in groundwater DOC as a result of microbial activity including oil biodegradation or microbially enhanced oil recovery. We describe the limitations of this new instrument for the analysis of DOC in brines including sample requirements, matrix effects, and the effect of DOC composition on reaction efficiency and isotopic measurements. We compare strategies including anion exchange cartridges, persulfate reactant concentrations, and reaction time. The CRDS analysis of DOC in brines is a useful tool for understanding the origin and fate of DOC and is a potentially powerful tool to identifiy evidence of contamination due to hydrofracturing chemicals that have a distinctive carbon isotopic signature relative to natural brine.

  13. Sewage-sludge-derived carbonaceous materials for catalytic wet hydrogen peroxide oxidation of m-cresol in batch and continuous reactors.

    Science.gov (United States)

    Yu, Yang; Wei, Huangzhao; Yu, Li; Wang, Wei; Zhao, Ying; Gu, Bin; Sun, Chenglin

    2016-01-01

    In this study, four sewage-sludge-derived carbonaceous materials (SWs) were evaluated for their catalytic wet hydrogen peroxide oxidation (CWPO) performance of m-cresol in batch reactor and continuous reactor, respectively. The SWs were produced by carbonization (SW); carbonization with the addition of CaO (CaO-SW); HNO3 pretreatment (HNO3-SW) and steam activation (Activated-SW). The properties of SW catalysts were assessed by thermogravimetric analysis, Brunauer-Emmett-Teller, Fourier Transform Infrared Spectroscopy, X-ray Fluorescence, Scanning electron microscopy, energy dispersive X-ray analysis and zeta potential. The results showed that SW treated by HNO3 (HNO3-SW) had a high conversion of m-cresol in batch reactor and continuous reactor, respectively. Under the conditions of batch reaction (Cm-cresol = 100 mg L(-1), CH2O2 = 15.7 mmol L(-1), initial pH=7.0, 0.5 g L(-1) catalyst, 80°C, 180 min adsorption and 210 min oxidation), the conversion of m-cresol reached 100% and total organic carbon removal was 67.1%. It had a high catalytic activity and stability on the treatment of m-cresol in CWPO for more than 1100 h. Furthermore, a possible reaction mechanism for the oxidation of m-cresol to 2-methyl-p-benzoquinone by CWPO was proposed. PMID:26109374

  14. CuZnAl Mixed Oxide Catalyst Prepared from Hydrotalcite-like Precursor for Catalytic Wet Oxidation of Phenol%由类水滑石前驱体制备的CuZnAl复合氧化物催化剂催化湿氧化处理苯酚

    Institute of Scientific and Technical Information of China (English)

    孙颖; 杨民; 窦和瑞; 何雨; 王炜; 孙承林

    2003-01-01

    @@ The efficiency of several noble metals for catalytic wet oxidation (CWO) of various pollutants has been demonstrated[1,2]. However, the noble metals are expensive, affecting greatly the economics of the corresponding process.

  15. Treatment of aniline by catalytic wet air oxidation: comparative study over CuO/CeO2 and NiO/Al2O3.

    Science.gov (United States)

    Ersöz, Gülin; Atalay, Süheyda

    2012-12-30

    The treatment of aniline by catalytic wet air oxidation (CWAO) was studied in a bubble reactor. The experiments were performed to investigate the effects of catalyst loading, temperature, reaction time, air flow rate, and pressure on aniline removal. The catalytic effects of the prepared nanostructured catalysts, CuO/CeO(2) (10% wt) and NiO/Al(2)O(3) (10% wt), on the CWAO treatment efficiency were also examined and compared. The prepared catalysts seem to be active having an aniline removal of 45.7% with CuO/CeO(2) and 41.9% with NiO/Al(2)O(3). The amount of N(2) formed was approximately the same for both of the catalysts. PMID:23041516

  16. Degradation of H-acid in aqueous solution by microwave assisted wet air oxidation using Ni-loaded GAC as catalyst

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yao-bin; QUAN Xie; ZHAO Hui-min; CHEN Shuo; YANG Feng-lin

    2005-01-01

    A novel process, microwave assisted catalytic wet air oxidation(MW-CWO), was applied for the degradation of H-acid( 1-amino8-naphthol-3, 6-disulfonic acid) in aqueous solution. Ni-loaded granular activated carbon (GAG), prepared by immersion-calcination method, was used as catalyst. The results showed that the MW-CWO process was very effective for the degradation of H-acid in aqueous solution under atmospheric pressure with 87.4% TOC (total organic carbon) reduction in 20 min. Ni on GAC existed in the form of NiO as specified by XRD. Loss of Ni was significant in the initial stage, and then remained almost constant after 20 min reaction. BET surface area results showed that the surface property of GAC after MW-CWO process was superior to that of blank GAC.

  17. Subcritical and supercritical water oxidation of organic, wet wastes for carbon cycling in regenerative life support systems

    Science.gov (United States)

    Ronsse, Frederik; Lasseur, Christophe; Rebeyre, Pierre; Clauwaert, Peter; Luther, Amanda; Rabaey, Korneel; Zhang, Dong Dong; López Barreiro, Diego; Prins, Wolter; Brilman, Wim

    2016-07-01

    For long-term human spaceflight missions, one of the major requirements is the regenerative life support system which has to be capable of recycling carbon, nutrients and water from both solid and liquid wastes generated by the crew and by the local production of food through living organisms (higher plants, fungi, algae, bacteria, …). The European Space Agency's Life Support System, envisioned by the MELiSSA project, consists of a 5 compartment artificial ecosystem, in which the waste receiving compartment (so-called compartment I or briefly 'CI') is based on thermophilic fermentation. However, as the waste generated by the crew compartment and food production compartment contain typical plant fibres (lignin, cellulose and hemicellulose), these recalcitrant fibres end up largely unaffected in the digestate (sludge) generated in the C-I compartment. Therefore, the C-I compartment has to be supplemented with a so-called fibre degradation unit (in short, FDU) for further oxidation or degradation of said plant fibres. A potential solution to degrading these plant fibres and other recalcitrant organics is their oxidation, by means of subcritical or supercritical water, into reusable CO2 while retaining the nutrients in an organic-free liquid effluent. By taking advantage of the altered physicochemical properties of water above or near its critical point (647 K, 22.1 MPa) - including increased solubility of non-polar compounds and oxygen, ion product and diffusivity - process conditions can be created for rapid oxidation of C into CO2. In this research, the oxidizer is provided as a hydrogen peroxide solution which, at elevated temperature, will dissociated into O2. The purpose of this study is to identify ideal process conditions which (a) ensure complete oxidation of carbon, (b) retaining the nutrients other than C in the liquid effluent and (c) require as little oxidizer as possible. Experiments were conducted on a continuous, tubular heated reactor and on batch

  18. Improved method for the determination of nonpurgeable suspended organic carbon in natural water by silver filter filtration, wet chemical oxidation, and infrared spectrometry

    Science.gov (United States)

    Burkhardt, M.R.; Brenton, R.W.; Kammer, J.A.; Jha, V.K.; O'Mara-Lopez, P. G.; Woodworth, M.T.

    1999-01-01

    Precision and accuracy are reported for the first time for the analysis of nonpurgeable suspended organic carbon by silver membrane filtration followed by wet chemical oxidation. A water sample is pressure filtered through a 0.45-??m-pore-size, 47-mm-diameter silver membrane filter. The silver membrane filter then is cut into ribbons and placed in a flame-sealable glass ampule. The organic material trapped on the membrane filter strips is acidified, purged with oxygen to remove inorganic carbonates and volatile organic compounds, and oxidized to carbon dioxide (CO2) using phosphoric acid and potassium persulfate in the sealed glass ampule. The resulting CO2 is measured by a nondispersive infrared CO2 detector. The amount of CO2 is proportional to the concentration of chemically oxidizable nonpurgeable organic carbon in the environmental water sample. The quantitation and method detection limit for routine analysis is 0.2 mg/L. The average percent recovery in five representative matrices was 97 ?? 11%. The errors associated with sampling and sample preparation of nonpurgeable suspended organic carbon are also described.Precision and accuracy are reported for the first time for the analysis of nonpurgeable suspended organic carbon by silver membrane filtration followed by wet chemical oxidation. A water sample is pressure filtered through a 0.45-??m-pore-size, 47-mm-diameter silver membrane filter. The silver membrane filter then is cut into ribbons and placed in a flame-sealable glass ampule. The organic material trapped on the membrane filter strips is acidified, purged with oxygen to remove inorganic carbonates and volatile organic compounds, and oxidized to carbon dioxide (CO2) using phosphoric acid and potassium persulfate in the sealed glass ampule. The resulting CO2 is measured by a nondispersive infrared CO2 detector. The amount of CO2 is proportional to the concentration of chemically oxidizable nonpurgeable organic carbon in the environmental water sample

  19. Functional, genomic and molecular characterisation of Mtl1, an element of the CWI pathway of Saccharomyces cerevisiae with a role in the oxidative stress response

    OpenAIRE

    Ivanova Petkova, Mima

    2011-01-01

    Saccharomyces cerevisiae és un microorganisme eucariota que s’utilitza com a model per l’estudi de les vies de transducció de senyal implicades en la resposta a estrès oxidatiu. Fins l’actualitat, no s’ha descrit l’existència d’una via específica de senyals d’oxidació. Mtl1 es un membre de la via CWI (Cell Wall Integrity: via d’integritat cel.lular) que funciona com un sensor transmembrana que dectecta l’estrès oxidatiu. En aquest estudi es demostra que Mtl1 es esencial en el p...

  20. Atmospheric peroxyacetyl nitrate measurements over the Brazilian Amazon Basin during the wet season - Relationships with nitrogen oxides and ozone

    Science.gov (United States)

    Singh, H. B.; Herlth, D.; O'Hara, D.; Salas, L.; Torres, A. L.; Gregory, G. L.; Sachse, G. W.

    1990-01-01

    An analysis is presented on the distribution and variability of PAN as well as its relationship with measured chemical and meteorological parameters. The chemicals of most interest for which measurements were available are PAN, NO(x), O3, CO, and C2Cl4. PAN was measured by the electron capture gas chromatographic technique, and the technique for calibrations and measurements are detailed. Data show that significant concentrations of PAN (5-125 ppt) are present during the wet season and this PAN is 1-5 times more abundant than NO(x). PAN levels at different atmospheric locations are discussed, and it is noted that PAN shows evidence of a possible latitudinal gradient in the free troposphere, with values falling rapidly from the northern midlatitudes toward the equator. High correlations between O3 and PAN levels suggest that nonmethane hydrocarbons may contribute significantly to high O3 in the free troposphere. Evidence indicates that virtually all of the NO(x) above 4 km could result from PAN decomposition.

  1. APPLICATION OF MAGNETIC CATALYSTS TO THE CATALYTIC WET PEROXIDE OXIDATION (CWPO OF INDUSTRIAL WASTEWATER CONTAINING NON BIODEGRADABLE ORGANIC POLLUTANTS

    Directory of Open Access Journals (Sweden)

    Macarena Munoz

    2014-03-01

    Full Text Available A new ferromagnetic -Al2O3-supported iron catalyst has been prepared and its activity and stability have been compared with those of a previous iron-based conventional catalyst and with the traditional homogeneous Fenton process in the oxidation of chlorophenols. The use of solid catalysts improved significantly the efficiency on the use of H2O2, achieving higher mineralization degrees. The magnetic catalyst led to significantly higher oxidation rates than the conventional one due to the presence of both Fe (II and Fe (III. On the other hand, the use of a catalyst with magnetic properties is of interest, since it allows rapid recovery after treatment using a magnetic field. Moreover, it showed a high stability with fairly low iron leaching (<1% upon CWPO runs. An additional clear advantage of this new catalyst is its easy separation and recovery from the reaction medium by applying an external magnetic field.

  2. Wet Aerobic Oxidation of Lignin into Aromatic Aldehydes Catalysed by a Perovskite-type Oxide: LaFe1-xCuxO3 (x=0, 0.1, 0.2

    Directory of Open Access Journals (Sweden)

    Lu Lin

    2009-07-01

    Full Text Available The perovskite-type oxide catalyst LaFe1-xCuxO3 (x=0, 0.1, 0.2 was prepared by the sol–gel method, and tested as a catalyst in the wet aerobic oxidation (WAO of lignin into aromatic aldehydes. The lignin conversion and the yield of each aromatic aldehyde were significantly enhanced in the catalytic process, compared with the non-catalyzed process. Moreover, it was shown that the stability of activity and structure of LaFe1-xCuxO3 (x=0, 0.1, 0.2 remained nearly unchanged after a series of successive recyclings of the catalytic reactions, indicating it was an efficient and recyclable heterogeneous catalyst for the conversion of lignin into aromatic aldehydes in the WAO process.

  3. Nanoscale analysis of the influence of pre-oxidation on oxide formation and wetting behavior of hot-dip galvanized high strength steel

    International Nuclear Information System (INIS)

    Highlights: • Pre-oxidized hot-dip galvanized advanced high strength steel was examined. • The interface was analyzed in detail via high energy resolution Auger spectra. • Evidence for an aluminothermic reduction of the Mn oxide was found. • A new model for galvanizing high manganese steel was developed. - Abstract: Hot-dip galvanized (HDG) 2nd generation advanced high strength steel (AHSS), nano-TWIP (twinning induced plasticity) with 15.8 wt.% Mn, 0.79 wt.% C, was analyzed at the interface between steel and zinc by scanning Auger electron microscopy (AES) in order to confirm and improve an existing model of additional pre-oxidation treatment before annealing and immersion into the hot zinc bath. Furthermore these steel samples were fractured in the analysis chamber of the AES and analyzed without breaking vacuum. In these measurements the results of an aluminothermic reduction of the manganese and iron surface oxides on the steel could be confirmed by AES

  4. A MEMS based acetone sensor incorporating ZnO nanowires synthesized by wet oxidation of Zn film

    International Nuclear Information System (INIS)

    In this work, we report a simple and efficient method for synthesis of ZnO nanowires by thermal oxidation of Zn film and their integration with MEMS technologies to fabricate a sensor for acetone vapour detection. ZnO nanowires were prepared by thermal oxidation of sputter deposited Zn film. The nanostructured ZnO was characterized by x-ray diffraction, a scanning electron microscope and room temperature photoluminescence measurements. The ZnO nanowires synthesis process was integrated with MEMS technologies to obtain a sensor for volatile organic compounds, incorporating an on-chip Ni microheater and an interdigited electrode structure. To reduce the heat loss from the on-chip microheater, the sensor was made on a thin silicon diaphragm obtained via a modified reactive ion etching process. This resulted in considerable power saving during sensor operation. For this, a three-mask process was used. The performance of the microheater was simulated on COMSOL and validated experimentally. The sensor has been tested for acetone vapour sensing and the operating parameters were optimized. The sensor has the ability to detect acetone vapour at 5 parts per million (ppm) concentrations when operated at 100 °C. The sensor consumed only 36 mW power and showed a high-sensitivity value of 26.3% for 100 ppm of acetone vapour. (paper)

  5. A MEMS based acetone sensor incorporating ZnO nanowires synthesized by wet oxidation of Zn film

    Science.gov (United States)

    Behera, Bhagaban; Chandra, Sudhir

    2015-01-01

    In this work, we report a simple and efficient method for synthesis of ZnO nanowires by thermal oxidation of Zn film and their integration with MEMS technologies to fabricate a sensor for acetone vapour detection. ZnO nanowires were prepared by thermal oxidation of sputter deposited Zn film. The nanostructured ZnO was characterized by x-ray diffraction, a scanning electron microscope and room temperature photoluminescence measurements. The ZnO nanowires synthesis process was integrated with MEMS technologies to obtain a sensor for volatile organic compounds, incorporating an on-chip Ni microheater and an interdigited electrode structure. To reduce the heat loss from the on-chip microheater, the sensor was made on a thin silicon diaphragm obtained via a modified reactive ion etching process. This resulted in considerable power saving during sensor operation. For this, a three-mask process was used. The performance of the microheater was simulated on COMSOL and validated experimentally. The sensor has been tested for acetone vapour sensing and the operating parameters were optimized. The sensor has the ability to detect acetone vapour at 5 parts per million (ppm) concentrations when operated at 100 °C. The sensor consumed only 36 mW power and showed a high-sensitivity value of 26.3% for 100 ppm of acetone vapour.

  6. 催化湿式氧化预处理造纸黑液%Pretreatment of Black Liquor by Catalytic Wet Air Oxidation

    Institute of Scientific and Technical Information of China (English)

    董振海; 李利敏; 闫海生; 于姗姗; 李秀珍; 毕延文

    2011-01-01

    采用连续式固定床反应器,利用自制稀土类复合金属氧化物催化剂对草浆造纸黑液进行了催化湿式氧化(CWAO)预处理研究.通过正交实验确定了最佳工艺条件为:进水COD 40 800 mg/L,空速0.8h-1,反应温度260℃,反应压力6.5 MPa.在此最佳条件下进行实验,COD去除率达90%.经CWAO工艺处理后,草浆造纸黑液的可生化性显著提高,BOD5/COD由0.11提高至0.62.在1 000 h CWAO连续实验中,自制稀土类复合金属氧化物催化剂显示出较高催化活性和较好的稳定性.%The black liquor from straw pulp paper-making was pretreated by catalytic wet air oxidation (CWAO) in the continuous fixed bed reactor with self-made rare earth oxide catalyst. The optimum process conditions determined by the orthogonal tests are as follows: influent COD 40 800 mg/L,space velocity 0. 8 h-1 .reaction temperature 260℃, reaction pressure 6. 5 Mpa. Under these conditions, the COD removal rate is 90%. The biodegradability of the treated black liquor is significantly improved with BOD5/COD increased from 0. 11 to 0. 62. During 1 000 h of the CWAO continuous experiment, the catalytic activity and stability of the self-made rare earth oxide catalyst are good.

  7. Wet oxidation of phenol over transition metal oxide catalysts supported on Ce0.65 Zr0.35 O2 prepared by continuous hydrothermal synthesis in supercritical water.

    Science.gov (United States)

    Kim, Kyoung-Hun; Kim, Jeong-Rang; Ihm, Son-Ki

    2009-08-15

    The mixed oxide (Ce(0.65)Zr(0.35)O(2)) prepared by supercritical synthesis was applied as a support of transition metal (Mn, Fe, Co, Ni, and Cu) oxide catalysts for catalytic wet oxidation (CWO) of phenol in view of their higher thermal stability, better oxygen storage capacity, and higher surface area. The prepared catalysts showed an enhanced catalytic activity for CWO of phenol due to the excellent redox properties of ceria-zirconia mixed oxide. Among the prepared catalysts, the CuO(x)/Ce(0.65)Zr(0.35)O(2) was the most effective catalyst in view of catalytic activity and CO(2) selectivity. The leached copper ions seem to contribute to the higher conversion of phenol over the CuO(x)/Ce(0.65)Zr(0.35)O(2) via homogeneous catalysis. The characterization with XPS, XANES, and TPR experiments confirmed that the active copper species in the CuO(x)/Ce(0.65)Zr(0.35)O(2) is highly dispersed Cu(2+) clusters. Although the MnO(x)/Ce(0.65)Zr(0.35)O(2) showed a high conversion of phenol and TOC, the converted phenol was mainly changed to carbon deposits on the surface of catalyst resulting in catalyst deactivation. PMID:19264401

  8. Profiling of the toxicity mechanisms of coated and uncoated silver nanoparticles to yeast Saccharomyces cerevisiae BY4741 using a set of its 9 single-gene deletion mutants defective in oxidative stress response, cell wall or membrane integrity and endocytosis.

    Science.gov (United States)

    Käosaar, Sandra; Kahru, Anne; Mantecca, Paride; Kasemets, Kaja

    2016-09-01

    The widespread use of nanosilver in various antibacterial, antifungal, and antiviral products warrants the studies of the toxicity pathways of nanosilver-enabled materials toward microbes and viruses. We profiled the toxicity mechanisms of uncoated, casein-coated, and polyvinylpyrrolidone-coated silver nanoparticles (AgNPs) using Saccharomyces cerevisiae wild-type (wt) and its 9 single-gene deletion mutants defective in oxidative stress (OS) defense, cell wall/membrane integrity, and endocytosis. The 48-h growth inhibition assay in organic-rich growth medium and 24-h cell viability assay in deionized (DI) water were applied whereas AgNO3, H2O2, and SDS served as positive controls. Both coated AgNPs (primary size 8-12nm) were significantly more toxic than the uncoated (~85nm) AgNPs. All studied AgNPs were ~30 times more toxic if exposed to yeast cells in DI water than in the rich growth medium: the IC50 based on nominal concentration of AgNPs in the growth inhibition test ranged from 77 to 576mg Ag/L and in the cell viability test from 2.7 to 18.7mg Ag/L, respectively. Confocal microscopy showed that wt but not endocytosis mutant (end3Δ) internalized AgNPs. Comparison of toxicity patterns of wt and mutant strains defective in OS defense and membrane integrity revealed that the toxicity of the studied AgNPs to S. cerevisiae was not caused by the OS or cell wall/membrane permeabilization. PMID:27260961

  9. 湿法烟气脱硫环境下亚硫酸钙的非催化氧化%NON-CATALYTIC OXIDATION KINETICS OF CALCIUM SULFITE IN WET LIMESTONE-GYPSUM FGD PROCESS

    Institute of Scientific and Technical Information of China (English)

    杜谦; 吴少华; 朱群益; 秦裕琨

    2003-01-01

    A study on non-catalytic oxidation kinetics of calcium sulfite is presented under typical conditions of wet flue gas desulfurization (FGD)in this paper. A laboratory-scale mechanically stirred tank reactor is used with continuous feed of both gas and liquid phase. The results show that increasing CaSO3 load from a lower value, the reaction rate increases and is limited by solid sulfite dissolution. The oxidation rate limitation is observed at loads exceeding certain concentration. The rate limitation is possibly caused by solid sulfite solubility or oxygen gas-liquid diffusion. The experimental conclusions are useful for design and operation of the holding tank in forced-oxidation wet FGD.

  10. Measurements of reactive nitrogen oxides (NO/y/) within and above a tropical forest canopy in the wet season

    Science.gov (United States)

    Bakwin, Peter S.; Wofsy, Steven C.; Fan, Song-Miao

    1990-01-01

    Measurements of ambient concentrations of reactive nitrogen oxides were made in the Amazon rain forest, near Manaus, Brazil, continuously at 39 m (above the canopy), and on several days and nights at 19 m (within the canopy). Concentrations were very low, typically 100-700 pptv, except for brief periods when up to 5000 pptv of NO(y) was observed, indicating polluted air from the urban area of Manaus. The forest was a net sink for NO(y) with the NO(y) flux = -7.6 + or - 5.0) x 10 to the 9th molecules/sq cm per sec in unpolluted periods, even though soils emitted NO at a significant rate (8.9 + or - 1.5 x 10 to the 9th molecules/sq cm per sec). The deposition rate for NO(y) appeared to be much larger during the daytime than at night, suggesting that uptake was controlled either by plant processes (stomatal opening) or by supply of reactive components of NO(y) (e.g., HNO3) during the daytime. Implications for regional and global atmospheric chemistry are discussed.

  11. Influence of organic acids and organochlorinated insecticides on metabolism of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Pejin Dušanka J.

    2005-01-01

    Full Text Available Saccharomyces cerevisiae is exposed to different stress factors during the production: osmotic, temperature, oxidative. The response to these stresses is the adaptive mechanism of cells. The raw materials Saccharomyces cerevisiae is produced from, contain metabolism products of present microorganisms and protective agents used during the growth of sugar beet for example the influence of acetic and butyric acid and organochlorinated insecticides, lindan and heptachlor, on the metabolism of Saccharomyces cerevisiae was investigated and presented in this work. The mentioned compounds affect negatively the specific growth rate, yield, content of proteins, phosphorus, total ribonucleic acids. These compounds influence the increase of trechalose and glycogen content in the Saccharomyces cerevisiae cells.

  12. Reliable wet-chemical cleaning of natively oxidized high-efficiency Cu(In,Ga)Se2 thin-film solar cell absorbers

    International Nuclear Information System (INIS)

    Currently, Cu-containing chalcopyrite-based solar cells provide the highest conversion efficiencies among all thin-film photovoltaic (PV) technologies. They have reached efficiency values above 20%, the same performance level as multi-crystalline silicon-wafer technology that dominates the commercial PV market. Chalcopyrite thin-film heterostructures consist of a layer stack with a variety of interfaces between different materials. It is the chalcopyrite/buffer region (forming the p-n junction), which is of crucial importance and therefore frequently investigated using surface and interface science tools, such as photoelectron spectroscopy and scanning probe microscopy. To ensure comparability and validity of the results, a general preparation guide for “realistic” surfaces of polycrystalline chalcopyrite thin films is highly desirable. We present results on wet-chemical cleaning procedures of polycrystalline Cu(In1-xGax)Se2 thin films with an average x = [Ga]/([In] + [Ga]) = 0.29, which were exposed to ambient conditions for different times. The hence natively oxidized sample surfaces were etched in KCN- or NH3-based aqueous solutions. By x-ray photoelectron spectroscopy, we find that the KCN treatment results in a chemical surface structure which is – apart from a slight change in surface composition – identical to a pristine as-received sample surface. Additionally, we discover a different oxidation behavior of In and Ga, in agreement with thermodynamic reference data, and we find indications for the segregation and removal of copper selenide surface phases from the polycrystalline material

  13. Carbon and nitrogen removal from glucose-glycine melanoidins solution as a model of distillery wastewater by catalytic wet air oxidation.

    Science.gov (United States)

    Phuong Thu, Le; Michèle, Besson

    2016-06-01

    Sugarcane molasses distillery wastewater contains melanoidins, which are dark brown recalcitrant nitrogenous polymer compounds. Studies were carried out in batch mode to evaluate Pt and Ru supported catalysts in the Catalytic Wet Air Oxidation (CWAO) process of a synthetic melanoidins solution, prepared by stoichiometric reaction of glucose with glycine. The addition of a catalyst slightly improved TOC removal compared with the non-catalytic reaction, and especially promoted the conversion of ammonium produced from organically-bound nitrogen in melanoidins to molecular nitrogen and nitrate. The selectivity to N2 attained 89% in the presence of the Pt catalysts in the reaction conditions used (TOC=2200mgL(-1), TN=280mgL(-1), 0.5g catalyst loaded with 3% metal, 210°C, 70bar total air pressure). To avoid leaching of the active metal by organically-bound nitrogen, the reaction was very efficiently performed in a two-step reaction consisting in WAO to convert nitrogen into ammonium, before the introduction of a catalyst. PMID:26900982

  14. Bubble-free ozone addition through ceramic membranes for wet-oxidative waste water treatment; Blasenfreier Ozoneintrag durch keramische Membranen zur nassoxidativen Abwasserbehandlung

    Energy Technology Data Exchange (ETDEWEB)

    Janknecht, P.; Wilderer, P.A. [Technische Univ. Muenchen, Garching (Germany). Lehrstuhl und Pruefamt fuer Wasserguete- und Abfallwirtschaft

    1999-07-01

    A prerequisite for successful wet oxidation is very accurately tuned and carefully monitored process control. In the alternative, a decline in water quality is actually possible. In particular, earlier studies in the ozonification of landfill leachate encountered problems in reducing levels of AOX in the presence of halogenated hydrocarbons. Serious problems in process control may arise when ozone is conventionally added and forms bubbles in the presence of surface-active substances; this foam accumulates and is so persistent as to evade mechanical control. Since the formation of foam is directly due to gas bubbles carried in, bubble-free addition of ozone through a membrane may be a viable approach. (orig.) [German] Voraussetzung fuer den Erfolg einer Nassoxidation ist eine sehr genau eingestellte und sorgfaeltig ueberwachte Prozessfuehrung, da anderenfalls auch eine Verschlechterung der Wasserqualitaet eintreten kann; insbesondere haben sich hier bei frueheren Untersuchungen zur Ozonung von Deponiesickerwaessern Schwierigkeiten bei der Reduzierung des AOX-Wertes in Anwesenheit von halogenierten Kohlenwasserstoffen ergeben. Gravierende Schwierigkeiten in der Prozessfuehrung kann Schaum bereiten, der sich bei konventionellem Blaseneintrag des Ozons in Anwesenheit von oberflaechenaktiven Substanzen bildet, sich in der Anlage ansammelt und dabei so bestaendig ist, dass er auf mechanische Weise nicht zu kontrollieren ist. Da die Schaumbildung direkt auf die eingetragenen Gasblasen zurueckzufuehren ist, stellt der blasenfreie Eintrag von Ozon durch eine Membran einen moeglichen Loesungsansatz dar. (orig.)

  15. Photocatalytic oxidation of nitric oxide from simulated flue gas by wet scrubbing using ultraviolet/TiO2/H2O2 process

    Institute of Scientific and Technical Information of China (English)

    张波; 仲兆平; 付宗明

    2015-01-01

    Nitric oxide (NO) from flue gas is hard to remove because of low solubility and reactivity. A new technology for photocatalytic oxidation of NO using ultraviolet (UV)/TiO2/H2O2 process is studied in an efficient laboratory-scale reactor. Effects of several key operational parameters on NO removal efficiency are studied, including TiO2 content, H2O2 initial concentration, UV lamp power, NO initial content, oxygen volume fraction and TiO2/H2O2 solution volume. The results illustrate that the NO removal efficiency increases with the increasing of H2O2 initial concentration or UV lamp power. Meanwhile, a lower NO initial content or a higher TiO2/H2O2 solution volume will result in higher NO removal efficiency. In addition, oxygen volume fraction has a little effect. The highest NO removal efficiency is achieved at the TiO2 content of 0.75 g/L, H2O2 initial concentration of 2.5 mol/L, UV lamp power of 36 W, NO initial content of 206×10−6 and TiO2/H2O2 solution volume of 600 mL. It is beneficial for the development and application of NO removal from coal-fired flue gas with UV/TiO2/H2O2 process.

  16. Conference: the wet catalytic oxidation, a technology for the removal of organic pollutants in industrial waters; Conference: l'oxydation voie humide catalytique, une technologie pour l'elimination des polluants organiques dans les eaux industrielles

    Energy Technology Data Exchange (ETDEWEB)

    Besson, M. [Institut de recherches sur la catalyse - CNRS, 2 avenue Albert Einstein, 69626 Villeurbanne Cedex (France)

    2004-07-01

    In this conference, it is taken stock on the use of catalysts in the wet oxidation process. Supported (TiO{sub 2}, ZrO{sub 2}....) heterogeneous metallic catalysts (Pt, Ru...) are particularly studied. It is shown that this type of catalysts can answer to the required characteristics: activity for the removal of organic matter, lack of active metal leaching in aqueous acid medium, no deactivation...Examples are given. (O.M.)

  17. Investigation on preparation of CuO-SnO2-CeO2/γ-Al2O3 catalysts for catalytic wet air oxidation process and their catalytic activity for degradation of phenol

    Institute of Scientific and Technical Information of China (English)

    SUN Xiao-jun; ZHANG Mi-lin; WAN Jia-feng; XIA Zhi; LIU Xiao-hui; LIU hui

    2008-01-01

    Catalytic Wet Air Oxidation process is an efficient measure for treatment of wastewater with great strength which is not biodegradable. Heterocatalysts now become the key investigation subject of catalytic wet air oxidation process due to their good stability and easy separation. In the paper, CuO-SnOE-CeO2/γ-Al2O3 catalysts are prepared by impregnation method, with SnO2 as a doping component, CuO as an active component, CeO2 as a structure stabilizer, γ-Al2O3 as a substrate. XPS test is carried out to investigate the effect of Sn on the chemical surrounding of Cu and O element on the catalyst surface and their catalytic activity. It is shown that the right do-ping of Sn can increase Cu+ content on the catalyst surface, as a result the quantity of adsorption oxygen is also increased. It is found that Cu + content on the catalyst surface is one of the primary factors that determin catalytic activity of catalyst through analyzing the catalytic wet air oxidation process of phenol.

  18. Electrical and physical characterizations of the effects of oxynitridation and wet oxidation at the interface of SiO2/4H-SiC(0001) and (000\\bar{1})

    Science.gov (United States)

    Shiomi, Hiromu; Kitai, Hidenori; Tsujimura, Masatoshi; Kiuchi, Yuji; Nakata, Daisuke; Ono, Shuichi; Kojima, Kazutoshi; Fukuda, Kenji; Sakamoto, Kunihiro; Yamasaki, Kimiyohi; Okumura, Hajime

    2016-04-01

    The effects of oxynitridation and wet oxidation at the interface of SiO2/4H-SiC(0001) and (000\\bar{1}) were investigated using both electrical and physical characterization methods. Hall measurements and split capacitance-voltage (C-V) measurements revealed that the difference in field-effect mobility between wet oxide and dry oxynitride interfaces was mainly attributed to the ratio of the mobile electron density to the total induced electron density. The surface states close to the conduction band edge causing a significant trapping of inversion carriers were also evaluated. High-resolution Rutherford backscattering spectroscopy (HR-RBS) analysis and high-resolution elastic recoil detection analysis (HR-ERDA) were employed to show the nanometer-scale compositional profile of the SiC-MOS interfaces for the first time. These analyses, together with cathode luminescence (CL) spectroscopy and transmission electron microscopy (TEM), suggested that the deviations of stoichiometry and roughness at the interface defined the effects of oxynitridation and wet oxidation at the interface of SiO2/4H-SiC(0001) and (000\\bar{1}).

  19. Abatement of phenolic mixtures by catalytic wet oxidation enhanced by Fenton's pretreatment: Effect of H2O2 dosage and temperature

    International Nuclear Information System (INIS)

    Catalytic wet oxidation (CWO) of a phenolic mixture containing phenol, o-cresol and p-cresol (500 mg/L on each pollutant) has been carried out using a commercial activated carbon (AC) as catalyst, placed in a continuous three-phase reactor. Total pressure was 16 bar and temperature was 127 deg. C. Pollutant conversion, mineralization, intermediate distribution, and toxicity were measured at the reactor outlet. Under these conditions no detoxification of the inlet effluent was found even at the highest catalyst weight (W) to liquid flow rate (QL) ratio used. On the other hand, some Fenton Runs (FR) have been carried out in a batch way using the same phenolic aqueous mixture previously cited. The concentration of Fe2+ was set to 10 mg/L. The influence of the H2O2 amount (between 10 and 100% of the stoichiometric dose) and temperature (30, 50, and 70 deg. C) on phenols conversion, mineralization, and detoxification have been analyzed. Phenols conversion was near unity at low hydrogen peroxide dosage but mineralization and detoxification achieved an asymptotic value at each temperature conditions. The integration of Fenton reagent as pretreatment of the CWO process remarkably improves the efficiency of the CWO reactor and allows to obtain detoxified effluents at mild temperature conditions and relatively low W/QL values. For a given phenolic mixture a temperature range of 30-50 deg. C in the Fenton pretreatment with a H2O2 dosage between 20 and 40% of the stoichiometric amount required can be proposed

  20. Comparative study of supported CuOx and MnOx catalysts for the catalytic wet air oxidation of β-naphthol

    International Nuclear Information System (INIS)

    Highlights: ► Degradation of β-naphthol was carried out by CWAO and the COD removal was 93.7%. ► Comparative study of supported CuOx and MnOx catalysts was implemented. ► Destruction of β-naphthol was catalyzed by metal oxides supported on nano-TiO2. - Abstract: MnOx/nano-TiO2, MnOx/Al2O3–TiO2 (Al-Ti), CuOx/nano-TiO2 and CuOx/Al-Ti were prepared and their application in catalytic wet air oxidation (CWAO) of β-naphthol were investigated. The catalysts had been characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR) measurements. Phases of CuO, Cu2O, CuAl2O4, MnO2 and Mn2O3 could be found on the surface of the aforementioned catalysts. Significant differences in activities were observed among the prepared catalysts. Compared to CuOx/nano-TiO2, the combined action of highly dispersed CuO as well as CuAl2O4 of CuOx/Al-Ti helped to achieve higher activity for the CWAO of β-naphthol, while the Cu2O component lead to lower efficiency of CuOx/nano-TiO2. On the surface of MnOx/nano-TiO2, both the larger amount of highly dispersed MnO2 and the stronger electron transfer between MnO2 and Mn2O3 were helpful to promote the activity for the degradation of β-naphthol. However, the higher amount of bulk MnO2 and the weaker electron transfer for MnOx/Al-Ti were unfavorable to increase its efficiency. Among the four catalysts as-prepared, MnOx/nano-TiO2 was identified the highest activity with 93.7% COD removal.

  1. A low-cost, high-throughput measurement for stable carbon isotope analysis of dissolved organic carbon in fresh water using wet chemical oxidation

    Science.gov (United States)

    Itoh, M.; Tayasu, I.; Yoshimizu, C.; Ohte, N.

    2011-12-01

    Isotope ratio mass spectrometer (IRMS) techniques can be used to analyze the 13C of dissolved organic carbon (DOC) in freshwater samples. The IRMS is usually interfaced with an elemental analyzer (EA) or a wet chemical oxidation (WCO) total organic carbon analyzer. However, the EA-IRMS technique typically requires water samples to be evaporated or freeze-dried, which requires much water and preparation time. Meanwhile, WCO-IRMS requires an expensive total organic carbon (TOC) analyzer for isotopic measurements and the instrument limits the flexibility of the analyses. Here, we propose a new method for analyzing the 13C of DOC in freshwater samples, using WCO. The analyses are performed using a GasBench II head space sampler (Thermo Electron) on-line with an IRMS. This method allows multi-sample processing, which includes the removal of dissolved inorganic carbon (DIC) and oxidation of DOC to CO2 on a dry heating block system. These procedures are conducted in glass vials, which are then placed in an auto sampler and analyzed on the GasBench II connected to the IRMS. It takes 20 min to remove both the DIC and WCO in the glass vials for multiple samples and 10 min to measure the carbon isotope in a sample. The main advantages of this method are the small sample volume requirement (10 μgC in a water sample), rapid analyses (~60 samples/d), and small initial cost if the laboratory already has a GasBench head space sampler. To investigate the performance of our method, we applied it to a solution of standard materials including some amino-acids, hydrogen phthalate, humic acids, and fulvic acids whose δ13C values were determined by EA-IRMS in advance. A good correlation was obtained between the δ13C values with the EA-IRMS measurement and with our method, using 6-ml standard solutions with a concentration of 2 mg-C/L (12 μgC). In our presentation, we will also show the results of DO13C measurements in natural fresh water, including soil water, groundwater, and stream

  2. Trx2p-dependent regulation of Saccharomyces cerevisiae oxidative stress response by the Skn7p transcription factor under respiring conditions.

    Directory of Open Access Journals (Sweden)

    Rocío Gómez-Pastor

    Full Text Available The whole genome analysis has demonstrated that wine yeasts undergo changes in promoter regions and variations in gene copy number, which make them different to lab strains and help them better adapt to stressful conditions during winemaking, where oxidative stress plays a critical role. Since cytoplasmic thioredoxin II, a small protein with thiol-disulphide oxidoreductase activity, has been seen to perform important functions under biomass propagation conditions of wine yeasts, we studied the involvement of Trx2p in the molecular regulation of the oxidative stress transcriptional response on these strains. In this study, we analyzed the expression levels of several oxidative stress-related genes regulated by either Yap1p or the co-operation between Yap1p and Skn7p. The results revealed a lowered expression for all the tested Skn7p dependent genes in a Trx2p-deficient strain and that Trx2p is essential for the oxidative stress response during respiratory metabolism in wine yeast. Additionally, activity of Yap1p and Skn7p dependent promoters by β-galactosidase assays clearly demonstrated that Skn7p-dependent promoter activation is affected by TRX2 gene deficiency. Finally we showed that deleting the TRX2 gene causes Skn7p hyperphosphorylation under oxidative stress conditions. We propose Trx2p to be a new positive efector in the regulation of the Skn7p transcription factor that controls phosphorylation events and, therefore, modulates the oxidative stress response in yeast.

  3. Reducing the genetic complexity of glycolysis in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Solis Escalante, D.

    2015-01-01

    Glycolysis, a biochemical pathway that oxidizes glucose to pyruvate, is at the core of sugar metabolism in Saccharomyces cerevisiae (bakers’ yeast). Glycolysis is not only a catabolic route involved in energy conservation, but also provides building blocks for anabolism. From an applied perspective,

  4. Investigation of biological partners by ESI Q-TOF mass spectrometry of Saccharomyces cerevisiae cytosolic thioredoxin peroxidase I (cTpxI ) and III (cTpxIII) by oxidative stress

    International Nuclear Information System (INIS)

    Full text: One of the oxidative protective mechanisms present in the cell is the peroxiredoxin family. This class of enzymes, present in prokaryotes and eukaryotes, promotes the elimination of H2O2 and alkyl hydrogen peroxides using reactive cysteines named peroxidatic cysteine (Cysp) and resolving cysteine (Cysr). Five peroxiredoxins have been discovered in Saccharomyces cerevisiae, three are cytosolic, one is mitochondrial, and another is nuclear. The present work aims the identification of cTPxIc170S and cTPxIIIc120S biological partners linked by mixed disulfide bonds in response to H2O2 and t-BOOH oxidative stress. We generated mutant cTPxIc170S and cTPxIIIc120S, purified by IMAC, treated with DTT, incubated with crude protein extracts of yeast ΔcTPxI/ΔcTPxII or ΔAHPI and challenge to H2O2 or t-BOOH to promote complexes formation. After the complexes were submitted to analysis by ESI Q-TOF mass spectrometry and processed using MASCOT MS/MS Ion Search. At present our results indicate interactions between cTPxIc170S and GSF2, a membrane protein that provides the secretion of hexose transporters; OMS1, a mitochondrial protein with a conserved methyltransferase motif; the hypothetical protein YGR031WP; TDH3p, a triose-phosphate dehydrogenase protein and RPS18ap, protein component of the small (40S) ribosomal subunit. Attached to cTPxIIIc120S it was identified Crn1p an protein that binds actin filaments (F-actin) and cross-links F-actin to form long actin filament bundles and identified its own isoform cTPxI. (author)

  5. DESTRUCTION OF TETRAPHENYLBORATE IN TANK 48H USING WET AIR OXIDATION BATCH BENCH SCALE AUTOCLAVE TESTING WITH ACTUAL RADIOACTIVE TANK 48H WASTE

    Energy Technology Data Exchange (ETDEWEB)

    Adu-Wusu, K; Paul Burket, P

    2009-03-31

    Wet Air Oxidation (WAO) is one of the two technologies being considered for the destruction of Tetraphenylborate (TPB) in Tank 48H. Batch bench-scale autoclave testing with radioactive (actual) Tank 48H waste is among the tests required in the WAO Technology Maturation Plan. The goal of the autoclave testing is to validate that the simulant being used for extensive WAO vendor testing adequately represents the Tank 48H waste. The test objective was to demonstrate comparable test results when running simulated waste and real waste under similar test conditions. Specifically: (1) Confirm the TPB destruction efficiency and rate (same reaction times) obtained from comparable simulant tests, (2) Determine the destruction efficiency of other organics including biphenyl, (3) Identify and quantify the reaction byproducts, and (4) Determine off-gas composition. Batch bench-scale stirred autoclave tests were conducted with simulated and actual Tank 48H wastes at SRNL. Experimental conditions were chosen based on continuous-flow pilot-scale simulant testing performed at Siemens Water Technologies Corporation (SWT) in Rothschild, Wisconsin. The following items were demonstrated as a result of this testing. (1) Tetraphenylborate was destroyed to below detection limits during the 1-hour reaction time at 280 C. Destruction efficiency of TPB was > 99.997%. (2) Other organics (TPB associated compounds), except biphenyl, were destroyed to below their respective detection limits. Biphenyl was partially destroyed in the process, mainly due to its propensity to reside in the vapor phase during the WAO reaction. Biphenyl is expected to be removed in the gas phase during the actual process, which is a continuous-flow system. (3) Reaction byproducts, remnants of MST, and the PUREX sludge, were characterized in this work. Radioactive species, such as Pu, Sr-90 and Cs-137 were quantified in the filtrate and slurry samples. Notably, Cs-137, boron and potassium were shown as soluble as a

  6. Modeled Wet Nitrate Deposition

    Data.gov (United States)

    U.S. Environmental Protection Agency — Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface...

  7. Introduction to wetting phenomena

    International Nuclear Information System (INIS)

    In these lectures the field of wetting phenomena is introduced from the point of view of statistical physics. The phase transition from partial to complete wetting is discussed and examples of relevant experiments in binary liquid mixtures are given. Cahn's concept of critical-point wetting is examined in detail. Finally, a connection is drawn between wetting near bulk criticality and the universality classes of surface critical phenomena. (author)

  8. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Daanen, H.A.M.; Kappers, A.M.L.

    2011-01-01

    The sensation of wetness is well-known but barely investigated. There are no specific wetness receptors in the skin, but the sensation is mediated by temperature and pressure perception. In our study, we have measured discrimination thresholds for the haptic perception of wetness of three di erent t

  9. Synthesis of ammonia directly from wet air using new perovskite oxide La0.8Cs0.2Fe0.8Ni0.2O3-δ as catalyst

    International Nuclear Information System (INIS)

    Single phase perovskite oxide La0.8Cs0.2Fe0.8Ni0.2O3-δ was synthesised to be used as electrocatalyst for electrochemical synthesis of ammonia directly from wet air. It exhibits an orthorhombic structure with space group Pnma(62); a = 5.5493(5) Å, b = 7.8352(10) Å, c = 5. 5295(5) Å, V = 240.42(4) Å3. Composite made of Ce0.8Gd0.2O2-δ (CGO) and (Li,Na,K)2CO3 was used as electrolyte. An ammonia formation rate of 9.21 × 10−7 mol s−1 m−2 was obtained at 400 °C when applied a voltage of 1.4 V, while wet air (3 mol% H2O) was introduced to the single chamber reactor. This is just slightly lower than the value of 1.23 × 10−6 mol s−1 m−2 when wet N2 (3 mol% H2O) was fed under the same experimental conditions. These values are more than two orders of magnitude higher than the reported ammonia formation rates when synthesised from N2 and H2O at ∼ 600 °C. The perovskite catalyst is also low cost compared to the Ru/MgO and Pt/C catalysts in previous reports. This experiment indicates that ammonia can be directly synthesised from wet air using low-cost catalysts. This is a very promising simple technology for sustainable synthesis of ammonia in the future

  10. Long term wet spent nuclear fuel storage

    International Nuclear Information System (INIS)

    The meeting showed that there is continuing confidence in the use of wet storage for spent nuclear fuel and that long-term wet storage of fuel clad in zirconium alloys can be readily achieved. The importance of maintaining good water chemistry has been identified. The long-term wet storage behaviour of sensitized stainless steel clad fuel involves, as yet, some uncertainties. However, great reliance will be placed on long-term wet storage of spent fuel into the future. The following topics were treated to some extent: Oxidation of the external surface of fuel clad, rod consolidation, radiation protection, optimum methods of treating spent fuel storage water, physical radiation effects, and the behaviour of spent fuel assemblies of long-term wet storage conditions. A number of papers on national experience are included

  11. 21 CFR 866.5785 - Anti-Saccharomyces cerevisiae (S. cerevisiae) antibody (ASCA) test systems.

    Science.gov (United States)

    2010-04-01

    ...) antibody (ASCA) test systems. 866.5785 Section 866.5785 Food and Drugs FOOD AND DRUG ADMINISTRATION... Immunological Test Systems § 866.5785 Anti-Saccharomyces cerevisiae (S. cerevisiae) antibody (ASCA) test systems. (a) Identification. The Anti-Saccharomyces cerevisiae (S. cerevisiae) antibody (ASCA) test system...

  12. H 2 O2湿式氧化法脱除铝酸钠溶液中的有机物%Removal of Organics From Industrial Sodium Aluminate Solution by Hydrogen Peroxide Wet Oxidation

    Institute of Scientific and Technical Information of China (English)

    杜振华; 李军旗; 金会心; 米秋秋

    2014-01-01

    By wet hydrogen peroxide oxidation ,the effects of alkali concentration ,oxidation time ,the amount of hydrogen peroxide and oxidation temperature on the removal of organics in Bayer liquor were investigated .The experiment results show that wet hydrogen peroxide oxidation method can effectively eliminate most of the organics in the sodium aluminate solution .T he better oxidation conditions is alkali concentration of 280 g/L ,oxidation temperature of 80 ℃ ,the amount of hydrogen peroxide of 80 mL ,oxidation time of 120 min for sodium aluminate solution of 80 mL .The removal rate of sodium oxalate is 65 .31% and the removal rate of total organic carbon is 60 .86% at the best conditions .T he process is simple ,no impurity is introduced in the system .%研究了采用 H2 O2湿式氧化法脱除某铝厂分解母液中的有机物,考察了母液苛性碱浓度、氧化时间、双氧水用量、温度对脱除有机物的影响。结果表明:H2 O2湿式氧化法可有效脱除铝酸钠溶液中的大部分有机物;试验获得的适宜工艺条件为苛性碱质量浓度280 g/L ,氧化时间120 min ,氧化温度80℃,双氧水用量80 mL。适宜条件下,草酸钠脱除率为65.31%,总有机物脱除率为60.86%。H2 O2湿式氧化法脱除铝酸钠溶液中有机物工艺简单,系统中不引入杂质。

  13. PREFACE: Dynamics of wetting Dynamics of wetting

    Science.gov (United States)

    Grest, Gary S.; Oshanin, Gleb; Webb, Edmund B., III

    2009-11-01

    Capillary phenomena associated with fluids wetting other condensed matter phases have drawn great scientific interest for hundreds of years; consider the recent bicentennial celebration of Thomas Young's paper on equilibrium contact angles, describing the geometric shape assumed near a three phase contact line in terms of the relevant surface energies of the constituent phases [1]. Indeed, nearly a century has passed since the seminal papers of Lucas and Washburn, describing dynamics of capillary imbibition [2, 3]. While it is generally appreciated that dynamics of fluid wetting processes are determined by the degree to which a system is out of capillary equilibrium, myriad complications exist that challenge the fundamental understanding of dynamic capillary phenomena. The topic has gathered much interest from recent Nobel laureate Pierre-Gilles de Gennes, who provided a seminal review of relevant dissipation mechanisms for fluid droplets spreading on solid surfaces [4] Although much about the dynamics of wetting has been revealed, much remains to be learned and intrinsic technological and fundamental interest in the topic drives continuing high levels of research activity. This is enabled partly by improved experimental capabilities for resolving wetting processes at increasingly finer temporal, spatial, and chemical resolution. Additionally, dynamic wetting research advances via higher fidelity computational modeling capabilities, which drive more highly refined theory development. The significance of this topic both fundamentally and technologically has resulted in a number of reviews of research activity in wetting dynamics. One recent example addresses the evaluation of existing wetting dynamics theories from an experimentalist's perspective [5]. A Current Opinion issue was recently dedicated to high temperature capillarity, including dynamics of high temperature spreading [6]. New educational tools have recently emerged for providing instruction in wetting

  14. Wetting in electrolyte solutions.

    Science.gov (United States)

    Ibagon, Ingrid; Bier, Markus; Dietrich, S

    2013-06-01

    Wetting of a charged substrate by an electrolyte solution is investigated by means of classical density functional theory applied to a lattice model. Within the present model the pure, i.e., salt-free solvent, for which all interactions are of the nearest-neighbor type only, exhibits a second-order wetting transition for all strengths of the substrate-particle and the particle-particle interactions for which the wetting transition temperature is nonzero. The influences of the substrate charge density and of the ionic strength on the wetting transition temperature and on the order of the wetting transition are studied. If the substrate is neutral, the addition of salt to the solvent changes neither the order nor the transition temperature of the wetting transition of the system. If the surface charge is nonzero, upon adding salt this continuous wetting transition changes to first-order within the wide range of substrate surface charge densities and ionic strengths studied here. As the substrate surface charge density is increased, at fixed ionic strength, the wetting transition temperature decreases and the prewetting line associated with the first-order wetting transition becomes longer. This decrease of the wetting transition temperature upon increasing the surface charge density becomes more pronounced by decreasing the ionic strength. PMID:23758391

  15. Anaplerotic Role for Cytosolic Malic Enzyme in Engineered Saccharomyces cerevisiae Strains

    NARCIS (Netherlands)

    Zelle, R.M.; Harrison, J.C.; Pronk, J.T.; Van Maris, A.J.A.

    2010-01-01

    Malic enzyme catalyzes the reversible oxidative decarboxylation of malate to pyruvate and CO2. The Saccharomyces cerevisiae MAE1 gene encodes a mitochondrial malic enzyme whose proposed physiological roles are related to the oxidative, malate-decarboxylating reaction. Hitherto, the inability of pyru

  16. Wet Gas Compressor Performance

    OpenAIRE

    Natås, Erik

    2014-01-01

    The world’s energy demand is increasing and more attention is given to increase the recovery of gas fields. Installing a compressor near the wellhead can contribute to this. Constantly changing reservoir conditions requires the system to handle small amounts of liquid water and condensate. Wet gas compression is a cost efficient and compact alternative to liquid separation on the seabed. A wet gas compressor test facility exists at NTNU`s thermal laboratory and research on wet gas fundam...

  17. Interfacial Reactions and Cubic Neodymium Oxide Formation in Low Dispersed Nd2O3-SiO2 System by Wet Chemical Method

    Institute of Scientific and Technical Information of China (English)

    S. Duhan; P. Aghamkar

    2009-01-01

    Neodymium (binary oxide) powders are synthesized by a solgel technique. Prepared powders are heat treated under different temperature for different time duration and obtained nanostructure of Nd. Metal particle have diameters in the range 7.8-21.6nm. It is found that the heat treatment plays an important role to produce different structure of Nd-doped silica matrix. The peak position shifts to lower angle as the size of the nano metal oxide particles size increases.

  18. Interfacial Reactions and Cubic Neodymium Oxide Formation in Low Dispersed Nd2O3-SiO2 System by Wet Chemical Method

    Science.gov (United States)

    Duhan, S.; Aghamkar, P.

    2009-01-01

    Neodymium (binary oxide) powders are synthesized by a solgel technique. Prepared powders are heat treated under different temperature for different time duration and obtained nanostructure of Nd. Metal particle have diameters in the range 7.8-21.6 nm. It is found that the heat treatment plays an important role to produce different structure of Nd-doped silica matrix. The peak position shifts to lower angle as the size of the nano metal oxide particles size increases.

  19. Improvement of wet-oxidized AlxGa1-xAs (x∼1) through the use of AlAs/GaAs digital alloys

    International Nuclear Information System (INIS)

    A comparison of the water vapor oxidation characteristics of AlAs, Al0.98Ga0.02As, and an AlxGa1-xAs digital alloy was performed. The AlxGa1-xAs digital alloy consists of periods of 49 monolayers of AlAs and 1 monolayer of GaAs and has an equivalent composition of x=0.98. Oxidation rates and the structural integrity of the three layers were compared. When oxidized in water vapor, the AlxGa1-xAs digital alloy and the AlAs have similar oxidation rates, both of which are twice as fast as the Al0.98Ga0.02As layer. Post-oxidation annealing of these samples at 450 degree sign C showed severe delamination at the oxide/GaAs interface in the AlAs sample while the AlxGa1-xAs digital alloy sample was not damaged. (c) 2000 American Institute of Physics

  20. Wetting and Photocatalytic Properties of TiO2 Nanotube Arrays Prepared via Anodic Oxidation of E-Beam Evaporated Ti Thin Films

    Directory of Open Access Journals (Sweden)

    Soon Wook Kim

    2015-01-01

    Full Text Available TiO2 nanotube arrays (TNAs are fabricated on quartz substrate by anodizing E-beam evaporated Ti films. E-beam evaporated Ti films are directly anodized at various anodizing voltages ranging from 20 to 45 V and their morphological, wetting, and photocatalytic properties are examined. The photocatalytic activity of the prepared TNAs is evaluated by the photodecomposition of methylene blue under UV illumination. The TNAs prepared at an anodizing voltage of 30 V have a high roughness of 30.1 nm and a low water contact angle of 7.5°, resulting in a high photocatalytic performance. The surface roughness of the TNAs is found to correlate inversely with the water contact angle. High roughness (i.e., high surface area, which leads to high hydrophilicity, is desirable for effective photocatalytic activity.

  1. Application of wet powder spraying for anode supported solid oxide fuel cell with a perovskite SrTi{sub 0.98}Nb{sub 0.02}O{sub 3-{delta}} anode

    Energy Technology Data Exchange (ETDEWEB)

    Gdaniec, Pawel; Karczewski, Jakub; Bochentyn, Beata; Gazda, Maria; Kusz, Boguslaw [Faculty of Applied Physics and Mathematics, Gdansk University of Technology, ul. Narutowicza 11/12, Gdansk, 80-233 (Poland); Molin, Sebastian; Jasinski, Piotr [Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, ul. Narutowicza 11/12, Gdansk, 80-233 (Poland); Krupa, Andrzej [Institute of Fluid Flow Machinery, Polish Academy of Sciences, ul. Fiszera 14, Gdansk, 80-231 (Poland)

    2013-12-15

    Anode-supported solid oxide fuel cell with SrTi{sub 0.98}Nb{sub 0.02}O{sub 3-{delta}}anode, yttria-stabilized zirconia electrolyte and La(Ni{sub 0.6}Fe{sub 0.4})O{sub 3{+-}{delta}} cathode has been successfully fabricated and evaluated. Process of anode support fabrication has been presented. Wet powder spraying and high temperature sintering method have been studied and applied to deposit the thin electrolyte layer.In order to improve catalytic properties of the anode, it has been impregnated with Ni. Electrical properties of fuel cells have been measured to determine their performance. The open cell voltage of 1.08 V and maximum power density at the level of 160 mWcm {sup -2} were observed at 800 C. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Disruption of the Saccharomyces cerevisiae homologue to the murine fatty acid transport protein impairs uptake and growth on long-chain fatty acids

    DEFF Research Database (Denmark)

    Færgeman, Nils J.; DiRusso, C C; Elberger, A;

    1997-01-01

    The yeast Saccharomyces cerevisiae is able to utilize exogenous fatty acids for a variety of cellular processes including beta-oxidation, phospholipid biosynthesis, and protein modification. The molecular mechanisms that govern the uptake of these compounds in S. cerevisiae have not been describe...

  3. Erosion corrosion in wet steam

    International Nuclear Information System (INIS)

    The effect of different remedies against erosion corrosion in wet steam has been studied in Barsebaeck 1. Accessible steam systems were inspected in 1984, 1985 and 1986. The effect of hydrogen peroxide injection of the transport of corrosion products in the condensate and feed water systems has also been followed through chemical analyses. The most important results of the project are: - Low alloy chromium steels with a chromium content of 1-2% have shown excellent resistance to erosion corrosion in wet steam. - A thermally sprayed coating has shown good resistance to erosion corrosion in wet steam. In a few areas with restricted accessibility minor attacks have been found. A thermally sprayed aluminium oxide coating has given poor results. - Large areas in the moisture separator/reheater and in steam extraction no. 3 have been passivated by injection of 20 ppb hydrogen peroxide to the high pressure steam. In other inspected systems no significant effect was found. Measurements of the wall thickness in steam extraction no. 3 showed a reduced rate of attack. - The injection of 20 ppb hydrogen peroxide has not resulted in any significant reduction of the iron level result is contrary to that of earlier tests. An increase to 40 ppb resulted in a slight decrease of the iron level. - None of the feared disadvantages with hydrogen peroxide injection has been observed. The chromium and cobalt levels did not increase during the injection. Neither did the lifetime of the precoat condensate filters decrease. (author)

  4. Wet Gas Compressor Transients

    OpenAIRE

    Owren, Bjørn Berge

    2014-01-01

    This master thesis considers three subtasks related to transient operation of wet gas compressors.HYSYS Dynamics is used to establish a dynamic simulation model in the first subtask. The model is designed to predict transient behavior of the compressor test facility at NTNU during dry and wet gas trip scenarios. Its steady state performance has been validated against test data. The deviation of polytropic head and suction volume flow is less than 1% for all test points but one.Dry and wet gas...

  5. Soil methane oxidation in both dry and wet temperate eucalypt forests show near identical relationship with soil air-filled porosity

    OpenAIRE

    Fest, Benedikt J.; Hinko-Najera, Nina; Wardlaw, Tim; Griffith, David W. T.; Livesley, Stephen J.; Arndt, Stefan K.

    2016-01-01

    Well-drained, aerated soils are important sinks for atmospheric methane (CH4) via the process of CH4 oxidation by methane oxidising bacteria (MOB). This terrestrial CH4 sink may contribute towards climate change mitigation, but the impact of changing soil moisture and temperature regimes on CH4 uptake is not well understood in all ecosystems. Temperate eucalypt forests in south-eastern Australia are predicted to experience rapid and extreme changes in rainfall patterns, temperatures and wild ...

  6. BIOSORPTION OF CHROMIUM (VI FROM INDUSTRIAL EFFLUENT BY WILD ANDMUTANT TYPE STRAIN OF SACCHAROMYCES CEREVISIAE AND ITS IMMOBILIZED FORM

    Directory of Open Access Journals (Sweden)

    K Selvam, K Arungandhi, B Vishnupriya, T Shanmuga priya and M Yamuna

    2013-01-01

    Full Text Available Biosorption of chromium was studied by wild type Saccharomyces cerevisiae strain, mutant strain, immobilized-wild type and mutant strain. Chromium absorption pattern was observed in all experimental conditions. Hexavalent chromium (VI was analyzed by diphenyl carbazide method, by oxidizing the trivalent chromium (III. The percentage efficiency of wild type S. cerevisiae and its mutant strain, immobilized-wild type and mutant strain were 94.8%, 98.7%, 97.4% and 100% respectively. S. cerevisiae mutant strain and their immobilized form was found to be effective in biosorption of chromium (VI than the wild type forms.

  7. Adsorption and wetting.

    NARCIS (Netherlands)

    Schlangen, L.J.M.

    1995-01-01

    Adsorption and wetting are related phenomena. In order to improve knowledge of both and their relations, experiments, thermodynamics and a theoretical interpretation have been connected, starring n-alkanes.Starting from the Gibbs adsorption equation thermodynamic relations between vapour adsorption

  8. 海藻酸钠TEMPO改性及其在造纸中的应用初探%Preliminary Study on TEMPO Oxidation of Sodium Alginate and Its Application on Wet-end of Paper

    Institute of Scientific and Technical Information of China (English)

    张玉娟; 戴红旗; 袁广翔; 房凯

    2012-01-01

    钙离子对实现造纸白水封闭循环有关键性的制约作用。通过对天然海藻酸钠进行改性来制备高羧基含量的化学助剂用于造纸湿部,可以起到控制钙离子影响的效果。通过测定2,2,6,6-四甲基哌啶-1-氧自由基(TEMPO)改性海藻酸钠羧基含量和螯合值,分析研究了NaClO用量、pH值和温度对反应过程的影响。选取氧化后羧基含量为2.14%、3.61%和未氧化(1.96%)的三组海藻酸钠添加到造纸湿部中进行应用实验,结果表明在一定的添加量下海藻酸钠能提高纸料的留着、滤水性能,并同时提高纸张强度。海藻酸钠加入量0.02%时最佳,并且羧基含量为3.61%的改性海藻酸钠作用效果最好。%Calcium ions play an important role in achieving closing white water circuit.Higher carboxyl content sodium alginate modified by 2,2,6,6-tetramethyl piperidine-1-oxyl radical(TEMPO) oxidation which could be used in wet-end was able to control the compact of calcium ions.Through the determination of carboxyl contents and chelate values of sodium alginate modified by TEMPO oxidation,the affect from dosage of NaClO,pH value and temperature to the oxidation process was researched.Three kinds of sodium alginate which contained different amounts of carboxyl groups(2.14%,3.61% and 1.96%) were selected for further use on wet-end of papermaking through capturing calcium ions.Results showed that both modified and unmodified sodium alginate could improve drainage/retention abilities of pulp and strength of paper sheets.Meanwhile,the most appropriate amount of sodium alginate was 0.02% and the sodium alginate which contained 3.61% of carboxyl group had the best affection among the three kind of sodium alginate.

  9. Cystathionine accumulation in Saccharomyces cerevisiae.

    OpenAIRE

    Ono, B; Suruga, T; Yamamoto, M.; Yamamoto, S.; Murata, K; Kimura, A; Shinoda, S; Ohmori, S.

    1984-01-01

    A cysteine-dependent strain of Saccharomyces cerevisiae and its prototrophic revertants accumulated cystathionine in cells. The cystathionine accumulation was caused by a single mutation having a high incidence of gene conversion. The mutation was designated cys3 and was shown to cause loss of gamma-cystathionase activity. Cysteine dependence of the initial strain was determined by two linked and interacting mutations, cys3 and cys1 . Since cys1 mutations cause a loss of serine acetyltransfer...

  10. Wetting of soluble polymers

    OpenAIRE

    Dupas, Julien

    2012-01-01

    The wetting of a soluble substrate is a situation commonly encountered in day-to-day life. For instance, the practical motivation of this study concerns the preparation of beverages using dehydrated powders, consisting of water-soluble substances such as carbohydrates. Hydrodynamical theories describing wetting onto insoluble substrates cannot account for experimental observations in the case of a liquid spreading onto a soluble substrate. Tay et al.(1) made the hypothesis that the water cont...

  11. Adsorption and wetting.

    OpenAIRE

    Schlangen, L.J.M.

    1995-01-01

    Adsorption and wetting are related phenomena. In order to improve knowledge of both and their relations, experiments, thermodynamics and a theoretical interpretation have been connected, starring n-alkanes.Starting from the Gibbs adsorption equation thermodynamic relations between vapour adsorption and wetting are derived. The surface pressure of a film, formed by vapour adsorption on a solid surface, is calculated by integrating the vapour adsorption isotherm. The surface pressure at the sat...

  12. Detoxification of Aflatoxin B1 by Saccharomyces cerevisiae Mutants of Anti-Oxidative Relating Genes%酿酒酵母抗氧化相关基因突变体对黄曲霉毒素B1的清除作用

    Institute of Scientific and Technical Information of China (English)

    史锋; 黄宇啸; 李永富

    2012-01-01

    黄曲霉毒素(AF)是粮食作物和饲料原料中容易污染的一种强毒性和强致癌性物质,酿酒酵母具有毒素清除功能.利用HPLC分析了酿酒酵母野生菌BY4742及三株关键的抗氧化相关基因缺失茵zwf1△、sod2△、glr1△对黄曲霉毒素B1的清除能力.结果表明,在PBS缓冲液中存活和死亡的细胞对AFB1的清除率分别为74%~76%和71%~73%,说明酵母细胞对AFB1的清除以生物吸附作用为主.在培养基中,3种突变菌活细胞对AFB1的清除率发生不同程度的降低,其中glr1△的AFB1清除能力下降最明显,其次是sod2△,而zwf1△下降最少,说明这些关键的抗氧化基因的缺失会影响细胞在生长状态下对AFB1的清除作用.%Aflatoxins are a group of mycotoxins with strong mutagenic and carcinogenic properties. Various commodities including crop and feed materials are easy to be contaminated with aflatoxin. Saccharomyces cerevisiae have been reported to bind or degrade aflatoxin. Here, detoxification of aflatoxin B1 (AFB1 ) by wild-type strain of S. cerevisiae (BY4742) and three mutants of anti-oxidative relating genes (zw/l△, sod2△and girl △) were determined by HPLC. In PBS buffer, AFBi binding abilities of viable and dead cells were 74% -76% and 71% — 73%, respectively, indicating AFB1 was removed by yeast cells mainly through cell adsorption. In YPD medium, clearance of AFB1 by three mutant viable cells reduced, while that by wild-type BY4742 remaining high. AFB1 binding ability of g/rlA decreased most seriously, then was that of sod2△ and zwfl△. Thus, the deletion of critical anti-oxidative relating genes would decrease the AFB1 binding ability of S. cerevisiae growing cells.

  13. BIOSORPTION OF CHROMIUM (VI) FROM INDUSTRIAL EFFLUENT BY WILD ANDMUTANT TYPE STRAIN OF SACCHAROMYCES CEREVISIAE AND ITS IMMOBILIZED FORM

    OpenAIRE

    K Selvam, K Arungandhi, B Vishnupriya, T Shanmuga priya and M Yamuna

    2013-01-01

    Biosorption of chromium was studied by wild type Saccharomyces cerevisiae strain, mutant strain, immobilized-wild type and mutant strain. Chromium absorption pattern was observed in all experimental conditions. Hexavalent chromium (VI) was analyzed by diphenyl carbazide method, by oxidizing the trivalent chromium (III). The percentage efficiency of wild type S. cerevisiae and its mutant strain, immobilized-wild type and mutant strain were 94.8%, 98.7%, 97.4% and 100% respectively. S. cerevisi...

  14. Effects of Al, Ga, and Ag on the anti-oxidation and wetting reactions of Sn-9Zn-X solders

    Institute of Scientific and Technical Information of China (English)

    Wang Hui; Xue Songbai; Chen Wenxue

    2009-01-01

    The effects of Ca, Al, and Ag on the anti-oxidation of Sn-9Zn-X solders and the interface reactions between the solders and Cu substrate were investigated by Auger electron spectroscopy (AES) and scanning electron microscope (SEM) analysis, respectively. The mechanism of improving the wettability of Sn-g Zn lead-flee solder by adding Ca, Al, and Ag was also revealed. The AES analysis indicated that Al and Ca might enrich on the molten solder surface which resulted in improving the anti-oxidation of Sn-gZn-O. O05Al and Sn-gZn-O. 3C, a alloys. The addition of Ca reduced the apparent activation energy and promoted the interface reaction. With the addition of 0.3 wt. % Ag, some scallop-like intermetallic compounds (IMCs) formed at the interface, according to the energy dispersive spectroscopy (EDS) analysis, these scallop-like IMCs might be the mixture of Ag-Zn and Cu-Sn compounds.

  15. Design and development of a prototype wet oxidation system for the reclamation of water and the disposition of waste residues onboard space vehicles

    Science.gov (United States)

    Jagow, R. B.

    1972-01-01

    Laboratory investigations to define optimum process conditions for oxidation of fecal/urine slurries were conducted in a one-liter batch reactor. The results of these tests formed the basis for the design, fabrication, and testing of an initial prototype system, including a 100-hour design verification test. Areas of further development were identified during this test. Development of a high pressure slurry pump, materials corrosion studies, oxygen supply trade studies, comparison of salt removal water recovery devices, ammonia removal investigation, development of a solids grinder, reactor design studies and bearing life tests, and development of shutoff valves and a back pressure regulator were undertaken. The development work has progressed to the point where a prototype system suitable for manned chamber testing can be fabricated and tested with a high degree of confidence of success.

  16. Progress in Metabolic Engineering of Saccharomyces cerevisiae

    OpenAIRE

    Nevoigt, Elke

    2008-01-01

    Summary: The traditional use of the yeast Saccharomyces cerevisiae in alcoholic fermentation has, over time, resulted in substantial accumulated knowledge concerning genetics, physiology, and biochemistry as well as genetic engineering and fermentation technologies. S. cerevisiae has become a platform organism for developing metabolic engineering strategies, methods, and tools. The current review discusses the relevance of several engineering strategies, such as rational and inverse metabolic...

  17. Wet storage integrity update

    International Nuclear Information System (INIS)

    This report includes information from various studies performed under the Wet Storage Task of the Spent Fuel Integrity Project of the Commercial Spent Fuel Management (CSFM) Program at Pacific Northwest Laboratory. An overview of recent developments in the technology of wet storage of spent water reactor fuel is presented. Licensee Event Reports pertaining to spent fuel pools and the associated performance of spent fuel and storage components during wet storage are discussed. The current status of fuel that was examined under the CSFM Program is described. Assessments of the effect of boric acid in spent fuel pool water on the corrosion and stress corrosion cracking of stainless steel and the stress corrosion cracking of stainless steel piping containing stagnant water at spent fuel pools are discussed. A list of pertinent publications is included. 84 references, 21 figures, 11 tables

  18. Fungal genomics beyond Saccharomyces cerevisiae?

    DEFF Research Database (Denmark)

    Hofmann, Gerald; Mcintyre, Mhairi; Nielsen, Jens

    2003-01-01

    Fungi are used extensively in both fundamental research and industrial applications. Saccharomyces cerevisiae has been the model organism for fungal research for many years, particularly in functional genomics. However, considering the diversity within the fungal kingdom, it is obvious that the...... application of the existing methods of genome, transcriptome, proteome and metabolome analysis to other fungi has enormous potential, especially for the production of food and food ingredients. The developments in the past year demonstrate that we have only just started to exploit this potential....

  19. Reactive wetting by liquid sodium on thin Au platin

    International Nuclear Information System (INIS)

    For practical use of an under-sodium viewer, the behavior of sodium wetting is investigated by modeling the reactive and non-reactive wetting of metallic-plated steels by liquid sodium to simulate sodium wetting. The non-reactive wetting simulation results showed good agreement with Tanner's law, in which the time dependencies of the droplet radius and contact angle are expressed as RN ∝ t1/10 and θ∝ t-3/10, respectively; therefore, the model was considered suitable for the simulation. To simulate reactive wetting, the model of fluid flow induced by the interfacial reaction was incorporated into the simulation of non-reactive wetting. The reactive wetting simulation results, such as the behavior of the precursor liquid film and central droplet, showed good agreement with sodium wetting experiments using thin Au plating at 250°C. An important result of the reactive wetting simulation is that the gradient of the reaction energy at the interface appeared on the new interface around the triple line, and that fluid flow was induced. This interfacial reactivity during sodium wetting of thin Au plating was enhanced by the reaction of sodium and nickel oxide through pinholes in the plating. (author)

  20. Research Progress on Catalyst of Catalytic Wet Air Oxidation for Phenol Wastewater%催化湿式氧化含酚废水催化剂的研究进展

    Institute of Scientific and Technical Information of China (English)

    李荣; 段大勇

    2015-01-01

    Catalytic wet air oxidation ( CWAO ) technology is an effective technology for phenol wastewater, developing and selecting suitable catalyst is a key factor of CWAO. Active components were briefly introduced and CWAO catalyst for phenol wastewater treatment was carried out. It was specified that selecting the best combination of suitable active component and carrier of CWAO catalyst can improve the efficiency of phenol degradation, developing the catalyst with high activity, stability and cheap characteristics was the development direction of CWAO for phenol wastewater treatment.%催化湿式氧化技术是处理含酚废水的有效技术,此技术的关键是合适催化剂的研制和选用。本文对催化湿式氧化含酚废水催化剂的活性组分、载体等情况进行了综述,并指出选用最佳活性组分和载体的组合能够提高催化剂对苯酚的降解效率,研发高活性、高稳定性及廉价的催化剂是催化湿式氧化含酚废水的发展方向。

  1. Evaluatie wet op orgaandonatie

    OpenAIRE

    Rosendal, H.; Beekum, W.T. van; Legemaate, J.; Buisen, M.A.J.M.; Hulst, E.H.; Berg, M. van den; Assink, A.; Veen, E.B. van; Davidse, W.; Swagerman, M.B.; Chorus, A.M.J.; Brodin, H.F.T.; Riet, A. van 't; van Dijk, P.

    2001-01-01

    Met de invoering van de Wet op de orgaandonatie (WOD) is een viertal doelen nagestreefd, namelijk het bieden van rechtszekerheid aan betrokkenen, het bevorderen van het aanbod van geschikte organen en weefsels, een rechtvaardige verdeling hiervan en het voorkomen van handel in organen en weefsels. De onderzoekers concluderen dat bovengenoemde doelen ten dele zijn gerealiseerd.

  2. Wetting of real surfaces

    CERN Document Server

    Bormashenko, Edward Yu

    2013-01-01

    The problem of wetting and drop dynamics on various surfaces is very interesting from both the scientificas well as thepractical viewpoint, and subject of intense research.The results are scattered across papers in journals, sothis workwill meet the need for a unifying, comprehensive work.

  3. Wet hydrate dissolution plant

    Directory of Open Access Journals (Sweden)

    Stanković Mirjana S.

    2003-01-01

    Full Text Available The IGPC Engineering Department designed basic projects for a wet hydrate dissolution plant, using technology developed in the IGPC laboratories. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant with capacity of 50,000 t/y was manufactured, at "Zeolite Mira", Mira (VE, Italy, in 1997, for increasing detergent zeolite production from 50,000 to 100,000 t/y. Several goals were realized by designing a wet hydrate dissolution plant. Main goal was increasing the detergent zeolite production capacity. The technological cycle of NaOH was closed, and no effluents emitted, and there is no pollution. Wet hydrate dissolution is now fully continuous, which is important for maintaining zeolite production quality, as well as for simplifying production. The wet hydrate production process is fully automatized, and the product has uniform quality. The production process can be controlled manually, which is necessary during start-up, and repairs. By installing additional process equipment (centrifugal pumps and dissolving reactors technological bottlenecks were overcome, and by adjusting NaOH tanks and dissolving reactors, the capacities of the process equipment was fully utilized.

  4. ACTIVITY OF SUPEROXIDE DISMUTASE ENZYME IN YEAST SACCHAROMYCES CEREVISIAE

    Directory of Open Access Journals (Sweden)

    Blažena Lavová

    2014-02-01

    Full Text Available Reactive oxygen species (ROS with reactive nitrogen species (RNS are known to play dual role in biological systems, they can be harmful or beneficial to living systems. ROS can be important mediators of damage to cell structures, including proteins, lipids and nucleic acids termed as oxidative stress. The antioxidant enzymes protect the organism against the oxidative damage caused by active oxygen forms. The role of superoxide dismutase (SOD is to accelerate the dismutation of the toxic superoxide radical, produced during oxidative energy processes, to hydrogen peroxide and molecular oxygen. In this study, SOD activity of three yeast strains Saccharomyces cerevisiae was determined. It was found that SOD activity was the highest (23.7 U.mg-1 protein in strain 612 after 28 hours of cultivation. The lowest SOD activity from all tested strains was found after 56 hours of cultivation of strain Gyöng (0.7 U.mg-1 protein.

  5. Stimulation of DNA repair in saccharomyces cerevisiae by ginkgo biloba leaf extract

    OpenAIRE

    Marques, Filipe; Azevedo, F; Johansson, Björn; Oliveira, Rui Pedro Soares de

    2011-01-01

    Many extracts prepared from plants traditionally used for medicinal applications contain a variety of phytochemicals with antioxidant and antigenotoxic activity. In this work we measured the DNA protective effect of extracts of Ginkgo biloba leaves from oxidative stress using Saccharomyces cerevisiae as experimental model. The extract improved viability of yeast cells under oxidative stress imposed by hydrogen peroxide. In accordance with previous reports on antioxidant properties of G. bilob...

  6. Xylose utilizing recombinant Saccharomyces cerevisiae strains

    Energy Technology Data Exchange (ETDEWEB)

    Walfridsson, M.

    1996-04-01

    Through metabolic engineering, S. cerevisiae was provided with the necessary enzymes required for xylose utilisation during ethanolic fermentation of xylose-rich lignocellulose raw materials. For xylitol production, S. cerevisiae was provided with the Pichia stipitis XYL1 gene encoding xylose reductase (XR). The in-vivo reduction and the following excretion of xylitol, requires a co-substrate for maintenance and cofactor regeneration. Xylitol yields close to 100% were obtained with the XYL1 containing S. cerevisiae. Introducing P. stipitis XYL1 and XYL2 genes, encoding XR and xylitol dehydrogenase (XDH), respectively, enabled S. cerevisiae to convert xylose to xylulose, via xylitol. During the screening work of P. stipitis XDH gene, another gene encoding a polyol dehydrogenase was isolated and cloned in S. cerevisiae. The gene was identified as a D-arabinitol dehydrogenase gene. In P. stipitis it may function as a redox sink by reducing D-ribulose to D-arabinitol. The metabolism through the pentose phosphate pathway (PPP) was enhanced by over-expressing the native genes TKL1 and TAL1 encoding transketolase and transaldolase, respectively, resulting in improved xylose utilisation. The XR and XDH activities in recombinant S. cerevisiae were produced at different levels by constructing yeast vectors in which the PGK1 and ADHI promoters controlled XYL1 and XYL2. With higher XDH than XR activities, less by-products, in the form of xylitol and glycerol, were formed by the recombinant S. cerevisiae strains. The Thermus thermophilus xylA gene encoding a thermostable xylose isomerase was cloned and expressed in S. cerevisiae. The recombinant xylose isomerase was actively produced and a new functional metabolic pathway was established in S. cerevisiae resulting in ethanol production from xylose. 150 refs, 3 figs, 4 tabs

  7. Wet blasting in conjunction with decommissioning

    International Nuclear Information System (INIS)

    -crystallization and through ion exchange. It may also be integrated into the oxide by filling vacancies present in the oxide. Activity is lower on cold system surfaces than on the hot surfaces because of the slower corrosion rate. The oxide layer is not as thick as on the hot system surfaces and the contamination has looser bonds to the oxide surface which makes it easier to decontaminate. One effective method to decontaminate components is wet blasting with glass beads or alumina oxide for a more effective peeling i.e., when decommissioning. When compared with the other main options available, high pressure cleaning, electro polishing and chemical bating, wet blasting provides comparable or better decontamination factors leaving a derived waste easier to handle and store. Wet blasting is compared to other methods a fast way to decontaminate components. When wet blasting the beads are surrounded with a film of water, so at the moment of impact against the components works like a pressure-absorbing cushion. This prevents the beads from being in direct contact with the metal surface. The oxides on the metal surface blows away by the pressure shock by the water-cushions around the beads. And in the aspect when it's time to decommission a plant where a huge systematic operation is needed, safety is important i.e. time exposed to active components. Wet blasting providing outer operator's position with proper radiation protection and more efficient blasting equipment results in a lesser dose taken by the operator. As mentioned oxides on cold system parts is easier to strip with wet blasting, while on hot system parts it's tougher and it could be profitable to first put the decontaminated parts in a electrolyte bath with i.e. Sodium sulfate solution (5% Na2SO4), to crack the oxide layer to easier remove it with wet blasting afterwards. Possible savings through wet blasting if equipment is used systematically in order to ensure that goods being sent for melting have an

  8. WET SOLIDS FLOW ENHANCEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2001-03-25

    The yield locus, tensile strength and fracture mechanisms of wet granular materials were studied. The yield locus of a wet material was shifted to the left of that of the dry specimen by a constant value equal to the compressive isostatic stress due to pendular bridges. for materials with straight yield loci, the shift was computed from the uniaxial tensile strength, either measured in a tensile strength tester or calculated from the correlation, and the angle of internal friction of the material. The predicted shift in the yield loci due to different moisture contents compare well with the measured shift in the yield loci of glass beads, crushed limestone, super D catalyst and Leslie coal. Measurement of the void fraction during the shear testing was critical to obtain the correct tensile strength theoretically or experimentally.

  9. Wetting phenomena in electrolyte solutions

    OpenAIRE

    Ibagon, Ingrid

    2014-01-01

    The present study analyzes wetting phenomena in electrolyte solutions. They are investigated by means of classical density functional theory. First, the wetting of a charged substrate by an electrolyte solution is studied with emphasis on the influence of the substrate charge density and of the ionic strength on the wetting transition temperature and on the order of the wetting transition. The corresponding models consist of solvent particles, anions, and cations. Two mean field approaches ar...

  10. Glycolipids of Saccharomyces cerevisiae Cell

    Directory of Open Access Journals (Sweden)

    Renuka Malhotra

    2005-01-01

    Full Text Available Total lipids of Saccharomyces cerevisiae were isolated by chloroform and methanol (2:1. Glycolipids were separated from total lipids by silicic acid chromatography. Glycolipid’s constituent sugars and fatty acids were analyzed by using Gas Liquid Chromatography. Galactose was the prominent sugar followed by mannose. Relative concentrations of fucose, mannose, galactose and glucose in the glycolipid were 5.3, 35.2, 55.1 and 4.2%. 16:0, 18:0, 18:1, 18:2 and 18:3 were the major fatty acids of the total glycolipids. Oleic acid was the dominating fatty acid followed by linoliec acid. They were separated into different fractions by using DEAE-Sephadex ion exchange chromatography. Glycolipids were fractionated and identified as cerebrosides, ceramide polyhexosides, sulfatides, monoglucosyldiglycerides and diglucosyldiglycerides. Ceramide polyhexosides were present in higher concentration as compared to other fractions.

  11. Glucose repression in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Kayikci, Omur; Nielsen, Jens

    2015-01-01

    Glucose is the primary source of energy for the budding yeast Saccharomyces cerevisiae. Although yeast cells can utilize a wide range of carbon sources, presence of glucose suppresses molecular activities involved in the use of alternate carbon sources as well as it represses respiration and...... gluconeogenesis. This dominant effect of glucose on yeast carbon metabolism is coordinated by several signaling and metabolic interactions that mainly regulate transcriptional activity but are also effective at post-transcriptional and post-translational levels. This review describes effects of glucose repression...... on yeast carbon metabolism with a focus on roles of the Snf3/Rgt2 glucose-sensing pathway and Snf1 signal transduction in establishment and relief of glucose repression....

  12. Methionine catabolism in Saccharomyces cerevisiae.

    Science.gov (United States)

    Perpète, Philippe; Duthoit, Olivier; De Maeyer, Simon; Imray, Louise; Lawton, Andrew I; Stavropoulos, Konstantinos E; Gitonga, Virginia W; Hewlins, Michael J E; Dickinson, J Richard

    2006-01-01

    The catabolism of methionine to methionol and methanethiol in Saccharomyces cerevisiae was studied using (13)C NMR spectroscopy, GC-MS, enzyme assays and a number of mutants. Methionine is first transaminated to alpha-keto-gamma-(methylthio)butyrate. Methionol is formed by a decarboxylation reaction, which yields methional, followed by reduction. The decarboxylation is effected specifically by Ydr380wp. Methanethiol is formed from both methionine and alpha-keto-gamma-(methylthio)butyrate by a demethiolase activity. In all except one strain examined, demethiolase was induced by the presence of methionine in the growth medium. This pathway results in the production of alpha-ketobutyrate, a carbon skeleton, which can be re-utilized. Hence, methionine catabolism is more complex and economical than the other amino acid catabolic pathways in yeast, which use the Ehrlich pathway and result solely in the formation of a fusel alcohol. PMID:16423070

  13. Degradation of phenol via wet-air oxidation over CuO/CeO2-ZrO2 nanocatalyst synthesized employing ultrasound energy: physicochemical characterization and catalytic performance.

    Science.gov (United States)

    Parvas, Mohsen; Haghighi, Mohammad; Allahyari, Somaiyeh

    2014-01-01

    Catalytic wet air oxidation (CWAO) of phenol was carried out under atmospheric pressure of oxygen at 160 degrees C in a stirred batch reactor over copper catalysts supported by CeO2-ZrO2. The copper with different loadings were impregnated over the composite support by a sonication process. The catalysts were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX), Brunauer-Emmett-Teller (BET) specific surface area and Fourier-transformed infrared analyses. Characteristic peaks attributed to copper were not found in XRD patterns even at high loadings, but based on EDX results, the existence of copper particles was confirmed. It means that sonochemical synthesis method even at high loadings produced small copper particles with low crystallinity and excellent dispersion over the CeO2-ZrO2 composite. FESEM micrographs indicated just slight enhancement in particle size at high loadings of Cu. Blank CWAO experiments illustrated low conversion of phenol using bare CeO2-ZrO2 support. Although some agglomeration of particles was found at high loadings of copper but owning to the fact that almost all ZrO2 particles incorporated into the CeO2 lattice at high contents of Cu, catalyst activity not only did not decrease but also the phenol conversion reached to the higher values. The optimal catalyst loading for phenol degradation was found to be 9 g/l. Complete conversion of phenol was achieved using CuO/CeO2-ZrO2 in 9 g/l catalyst loading with initial phenol concentration of 1000 ppm after 3 h of reaction. PMID:24701909

  14. Acetylation dynamics and stoichiometry in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Weinert, Brian Tate; Iesmantavicius, Vytautas; Moustafa, Tarek; Schölz, Christian; Wagner, Sebastian A; Magnes, Christoph; Zechner, Rudolf; Choudhary, Chuna Ram

    2014-01-01

    Lysine acetylation is a frequently occurring posttranslational modification; however, little is known about the origin and regulation of most sites. Here we used quantitative mass spectrometry to analyze acetylation dynamics and stoichiometry in Saccharomyces cerevisiae. We found that acetylation...

  15. TOTAL ANTIOXIDANT ACTIVITY OF YEAST SACCHAROMYCES CEREVISIAE

    OpenAIRE

    Blažena Lavová; Dana Urminská

    2013-01-01

    Antioxidants are health beneficial compounds that can protect cells and macromolecules (e.g. fats, lipids, proteins and DNA) from the damage of reactive oxygen species (ROS). Sacchamomyces cerevisiae are know as organisms with very important antioxidative enzyme systems such as superoxide dismutase or catalase. The total antioxidant activity (mmol Trolox equivalent – TE.g-1 d.w.) of Saccharomyces cerevisiae was measured by 2,2´-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) during the yeas...

  16. ESR ST study of hydroxyl radical generation in wet peroxide system catalyzed by heterogeneous ruthenium

    NARCIS (Netherlands)

    Rokhina, E.V.; Golovina, E.A.; As, van H.; Virkutyte, J.

    2009-01-01

    Ru-based catalysts gained popularity because of their applicability for a variety of processes, including carbon monoxide oxidation, wet air catalytic oxidation and wastewater treatment. The focus of a current study was generation of hydroxyl radicals in the wet peroxide system catalyzed by heteroge

  17. Wet steam wetness measurement in a 10 MW steam turbine

    Directory of Open Access Journals (Sweden)

    Kolovratník Michal

    2014-03-01

    Full Text Available The aim of this paper is to introduce a new design of the extinction probes developed for wet steam wetness measurement in steam turbines. This new generation of small sized extinction probes was developed at CTU in Prague. A data processing technique is presented together with yielded examples of the wetness distribution along the last blade of a 10MW steam turbine. The experimental measurement was done in cooperation with Doosan Škoda Power s.r.o.

  18. PREFACE: Wetting: introductory note

    Science.gov (United States)

    Herminghaus, S.

    2005-03-01

    The discovery of wetting as a topic of physical science dates back two hundred years, to one of the many achievements of the eminent British scholar Thomas Young. He suggested a simple equation relating the contact angle between a liquid surface and a solid substrate to the interfacial tensions involved [1], γlg cos θ = γsg - γsl (1) In modern terms, γ denotes the excess free energy per unit area of the interface indicated by its indices, with l, g and s corresponding to the liquid, gas and solid, respectively [2]. After that, wetting seems to have been largely ignored by physicists for a long time. The discovery by Gabriel Lippmann that θ may be tuned over a wide range by electrochemical means [3], and some important papers about modifications of equation~(1) due to substrate inhomogeneities [4,5] are among the rare exceptions. This changed completely during the seventies, when condensed matter physics had become enthusiastic about critical phenomena, and was vividly inspired by the development of the renormalization group by Kenneth Wilson [6]. This had solved the long standing problem of how to treat fluctuations, and to understand the universal values of bulk critical exponents. By inspection of the critical exponents of the quantities involved in equation~(1), John W Cahn discovered what he called critical point wetting: for any liquid, there should be a well-defined transition to complete wetting (i.e., θ = 0) as the critical point of the liquid is approached along the coexistence curve [7]. His paper inspired an enormous amount of further work, and may be legitimately viewed as the entrance of wetting into the realm of modern physics. Most of the publications directly following Cahn's work were theoretical papers which elaborated on wetting in relation to critical phenomena. A vast amount of interesting, and in part quite unexpected, ramifications were discovered, such as the breakdown of universality in thin film systems [8]. Simultaneously, a number

  19. SACCHAROMYCES CEREVISIAE AND ITS VALIDATION

    Directory of Open Access Journals (Sweden)

    Miroslav Ondrejovič

    2015-02-01

    Full Text Available The aim of this study was to optimize of independent variables as temperature, time and reaction ratio to output parameter of simultaneous enzyme saccharification and fermentation by Saccharomyces cerevisiae of pretreated wheat straw as model substrate via RSM (response surface methodology approach. As dependent variable, it was chosen ethanol yields characterizing effectivity of process. The optimal conditions were approximately temperature 100 °C, time 1 hour and reaction ratio 26 mL to 1 g of treated wheat straw with ethanol yields 141.9 mg.g-1. After calculating the optimal values, the validation analyze was carried out and it was found out that the predicted and experimentally verified dependent variable was in agreement with the optimal parameters (~ 95 %. Proposed model was tested for three lignocellulosic materials (winter wheat straw, alfalfa hay and maize straw as wheat straw used as model substrate and it was confirmed the possibility of its use for other agricultural residues with similar content of lignocellulose.

  20. Compositions and methods for modeling Saccharomyces cerevisiae metabolism

    DEFF Research Database (Denmark)

    2012-01-01

    The invention provides an in silica model for determining a S. cerevisiae physiological function. The model includes a data structure relating a plurality of S. cerevisiae reactants to a plurality of S. cerevisiae reactions, a constraint set for the plurality of S. cerevisiae reactions, and...... commands for determining a distribution of flux through the reactions that is predictive of a S. cerevisiae physiological function. A model of the invention can further include a gene database containing information characterizing the associated gene or genes. The invention further provides methods for...... making an in silica S. cerevisiae model and methods for determining a S. cerevisiae physiological function using a model of the invention. The invention provides an in silica model for determining a S. cerevisiae physiological function. The model includes a data structure relating a plurality of S...

  1. Selenium enrichment and anti-oxidant status in baker’s yeast, Saccharomyces cerevisiae at different sodium selenite concentrations Enriquecimiento con selenio y estado anti-oxidante de la levadura de harinas Saccharomyces Cerevisiae con diferentes concentraciones de selenito sódico

    Directory of Open Access Journals (Sweden)

    T. Kaur

    2006-12-01

    Full Text Available The use of selenized yeast as enriched selenium supplements in human nutrition has become a topic of increasing interest over the last decade. The present study was designed with the aim to achieve a balance between selenium (Se incorporation and optimal growth of yeast cells along with effect of Se enrichment on antioxidant defense status of yeast cells. Since oxidative stress has been known to play a role in the life span of all types of cells, so in the present studies anti-oxidant defense status was evaluated in the Se- enriched baker’s yeast cell culture model. Upon Se supplementation as sodium selenite at various concentrations in the growth medium, a continuous increase in glutathione peroxidase (GSH-Px activity and Se content was observed. In case of reduced glutathione (GSH decreasing trend were observed with increasing Se concentrations An increasing trend in total glutathione as well as glutathione-s-transferase activity was observed at increasing Se concentrations. Thus, Se supplementation significantly enhanced GSH-Px levels along with alterations in other anti-oxidant enzymes, suggesting the role of Se in the enzyme defense system of yeast against oxidative damage. Further, as Se exerts growth inhibitory effect on cells, the growth inhibition study was carried out and decrease in biomass was observed with increasing concentrations of Se. Due to nutritional benefits, Se-enriched yeast may be considered a safe source of Se supplementation.El uso de levaduras "selenizadas" como suplementos enriquecidos con selenio en nutrición humana se ha convertido en un tema de interés creciente en la última década. Este estudio se diseño con el objetivo de conseguir un equilibrio entre la incorporación de selenio (Se y el crecimiento óptimo de las células levaduriformes, junto con el efecto del enriquecimiento de Se sobre el estado de defensa anti-oxidante de las levaduras. Puesto que se sabe que el estrés oxidativo desempeña una funci

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

    Science.gov (United States)

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

    2016-03-15

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

  3. Wetting front instability in an initially wet unsaturated fracture

    International Nuclear Information System (INIS)

    Experimental results exploring gravity-driven wetting front instability in a pre-wetted, rough-walled analog fracture are presented. Initial conditions considered include a uniform moisture field wetted to field capacity of the analog fracture and the structured moisture field created by unstable infiltration into an initially dry fracture. As in previous studies performed under dry initial conditions, instability was found to result both at the cessation of stable infiltration and at flux lower than the fracture capacity under gravitational driving force. Individual fingers were faster, narrower, longer, and more numerous than observed under dry initial conditions. Wetting fronts were found to follow existing wetted structure, providing a mechanism for rapid recharge and transport

  4. Effect of in vitro digested cod liver oil of different quality on oxidative, proteomic and inflammatory responses in the yeast Saccharomyces cerevisiae and human monocyte-derived dendritic cells

    DEFF Research Database (Denmark)

    Larsson, Karin; Istenič, Katja; Wulff, Tune;

    2015-01-01

    oil with 22–53 µmol L−1 malondialdehyde and 0.26–3.7 µmol L−1 4-hydroxy-2-hexenal increased intracellular oxidation and cell energy metabolic activity compared to a digested blank in yeast cells and the influence of digests on mitochondrial protein expression was more pronounced for oxidised cod liver...... expression. The ratio of secreted cytokines, IL-12p40/IL-10, suggested a pro-inflammatory effect of the digested oils in relation to the blank (1.47–1.67 vs. 1.07). CONCLUSION: Gastro-intestinal digestion of cod liver oil increases the amount of oxidation products and resulting digests affect oxidation in...... oil than fresh cod liver oil. The four differentially expressed and identified proteins were related to energy metabolism and oxidative stress response. Maturation of dendritic cells was affected in the presence of digested fresh cod liver oil compared to the digested blank, measured as lower CD86...

  5. Fractionation of Phenolic Compounds Extracted from Propolis and Their Activity in the Yeast Saccharomyces cerevisiae

    OpenAIRE

    Petelinc, Tanja; Polak, Tomaž; Demšar, Lea; Jamnik, Polona

    2013-01-01

    We have here investigated the activities of Slovenian propolis extracts in the yeast Saccharomyces cerevisiae, and identified the phenolic compounds that appear to contribute to these activities. We correlated changes in intracellular oxidation and cellular metabolic energy in these yeasts with the individual fractions of the propolis extracts obtained following solid-phase extraction. The most effective fraction was further investigated according to its phenolic compounds.

  6. The utilization of some iron and zinc compounds as regulators of catalase activity at Saccharomyces cerevisiae

    OpenAIRE

    Efremova, N.; E. Molodoi; Usatîi, A.; Fulga, L.

    2013-01-01

    The main aim of this study was to examine the impact of some zinc and iron compounds as oxidative stress factors on catalase activity, which is known to be important defense system of microorganisms to metal stress. For the investigation was used baker's yeast strain - Saccharomyces cerevisiae CNMN-Y-11 previously selected as a source of protein and catalase. The obtained results have revealed that compounds of iron and zinc with citrate and acetate contributes to the accumulation of yeast bi...

  7. Ensiling – Wet-storage method for lignocellulosic biomass for bioethanol production

    DEFF Research Database (Denmark)

    Oleskowicz-Popiel, Piotr; Thomsen, Anne Belinda; Schmidt, Jens Ejbye

    2011-01-01

    Ensiling of humid biomass samples wrapped in plastic bales has been investigated as a wet-storage for bioethanol production from three lignocellulosic biomass samples i.e. maize, rye, and clover grass. During the silage process, lactic acid bacteria fermented free sugars to lactic acid, and...... consequently by lowing pH, inhibiting other microbes to degrade the polysaccharides. Following silage treatment, enzymatic convertibility tests showed that 51.5%, 36.5%, and 41.9% of the cellulose was converted by cellulytic enzymes in ensiled maize, rye, and clover grass, respectively. In addition, tests of.......5% (by S. cerevisiae); the yields significantly increased after hydrothermal pretreatment: 77.7%, 72.8%, 79.5% (by K. marxianus) and 72.0%, 80.7%, 75.7% (by S. cerevisiae) of the theoretical based on the C6 sugar contents in maize, rye, and clover grass, respectively....

  8. Wet flue gas desulphurization and new fuels

    Energy Technology Data Exchange (ETDEWEB)

    Kiil, S.; Dam-Johansen, K.; Michelsen, M.L.

    1998-04-01

    This thesis describes experimental and theoretical investigations of wet flue gas desulphurization (FGD). A review of the current knowledge of the various rate determining steps in wet FDG plants is presented. The mechanism underlying the rate of dissolution of finely grained limestone particles was examined in a laboratory batch apparatus using acid titration. Three Danish limestones of different origin were tested. A transient, mass transport controlled, mathematical model was developed to describe the dissolution process. Model predictions were found to be qualitatively in good agreement with experimental data. Empirical correlations for the dimensionless mass transfer coefficients in a pilot plant (falling-film column) were determined. The presence of inert particles in the liquid phase was found to decrease the rate of gas phase mass transport with up to 15%, though the effect could not be correlated. A detailed model for a wet FGD pilot plant, based on the falling film principle, was developed. All important rate determining steps, absorption of SO{sub 2}, oxidation of HSO{sub 3}{sup -}, dissolution of limestone, and crystallisation of gypsum were included. Model predictions were compared to experimental data such as gas phase concentration profiles of SO{sub 2}, slurry pH-profiles, solids contents of slurry, liquid phase concentrations, and residual limestone in the gypsum. The possibility of co-firing straw and coal was investigated in a full-scale power plant. No effects on the overall performance of the wet FGD plant were observed, though laboratory experiments with fine dust and fly ash from the full-scale experiments showed a decrease in limestone reactivity. (EG) EFP-95. 45 refs.; Also ph.d. thesis of Soeren Kiil

  9. Nitrogen Catabolite Repression in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Hofman-Bang, H Jacob Peider

    1999-01-01

    In Saccharomyces cerevisiae the expression of all known nitrogen catabolite pathways are regulated by four regulators known as Gln3, Gat1, Da180, and Deh1. This is known as nitrogen catabolite repression (NCR). They bind to motifs in the promoter region to the consensus sequence S' GATAA 3'. Gln3...

  10. Oscillations in glycolysis in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Kloster, Antonina; Olsen, Lars Folke

    Wehave investigated the glycolytic oscillations, measured as NADH autofluorescence, in the yeast Saccharomyces cerevisiae in a batch reactor. Specifically, we have tested the effect of cell density and a number of inhibitors or activators of ATPase activity on the amplitude of the oscillations. The...

  11. Tangential Ultrafiltration of Aqueous "Saccharomyces Cerevisiae" Suspensions

    Science.gov (United States)

    Silva, Carlos M.; Neves, Patricia S.; Da Silva, Francisco A.; Xavier, Ana M. R. B.; Eusebio, M. F. J.

    2008-01-01

    Experimental work on ultrafiltration is presented to illustrate the practical and theoretical principles of this separation technique. The laboratory exercise comprises experiments with pure water and with aqueous "Saccharomyces cerevisiae" (from commercial Baker's yeast) suspensions. With this work students detect the characteristic phenomena…

  12. Uranium recovery from wet process phosphoric acid

    International Nuclear Information System (INIS)

    In the field of metallurgy, specifically processes for recovering uranium from wet process phosphoric acid solution derived from the acidulation of uraniferous phosphate ores, problems of imbalance of ion exchange agents, contamination of recycled phosphoric acid with process organics and oxidizing agents, and loss and contamination of uranium product, are solved by removing organics from the raffinate after ion exchange conversion of uranium to uranous form and recovery thereof by ion exchange, and returning organics to the circuit to balance mono and disubstituted ester ion exchange agents; then oxidatively stripping uranium from the agent using hydrogen peroxide; then after ion exchange recovery of uranyl and scrubbing, stripping with sodium carbonate and acidifying the strip solution and using some of it for the scrubbing; regenerating the sodium loaded agent and recycling it to the uranous recovery step. Economic recovery of uranium as a by-product of phosphate fertilizer production is effected. (author)

  13. Erosion corrosion in a wet steam loop

    International Nuclear Information System (INIS)

    In a technical loop of a power plant erosion corrosion behaviour of the steels C 22.8, 15 Mo 3 and 10 Cr Mo 9 10 was investigated in test periods up to 78 days under definite conditions in wet steam of a relative steam content of about 75% at a temperature of 185 to 2000C and flow velocities up to 180 m/s. For comparison one test was carried out also in hot steam. By gravimetric, metallographic, SEM- and X-ray-diffraction analysis essential information was obtained on the kinetics of erosion corrosion and the structure of oxide coatings. The rate of erosion corrosion shows a high dependence on time and steel composition and decrease in the above mentioned order. Structure and quality of the oxide layer also show a remarkable dependence on steel composition. (orig.)

  14. Squeezing wetting and nonwetting liquids

    OpenAIRE

    Samoilov, V. N.; Persson, B. N. J.

    2004-01-01

    We present molecular-dynamics results for the squeezing of octane (C8H18) between two approaching solid elastic walls with different wetting properties. The interaction energy between the octane bead units and the solid walls is varied from a very small value (1 meV), corresponding to a nonwetting surface with a very large contact angle (nearly 180 degrees), to a high value (18.6 meV) corresponding to complete wetting. When at least one of the solid walls is wetted by octane we observe well d...

  15. Greenhouse gas microbiology in wet and dry straw crust covering pig slurry

    DEFF Research Database (Denmark)

    Hansen, Rikke Ruth; Nielsen, Daniel Aagren; Schramm, Andreas;

    2009-01-01

    microbiology had an effect on the emission of the potent greenhouse gases CH4 and nitrous oxide (N2O) when crust moisture was manipulated ("Dry", "Moderate", and "Wet"). The dry crust had the deepest oxygen penetration (45 mm as compared to 20 mm in the Wet treatment) as measured with microsensors, the highest...

  16. Wet Gas Compressor Surge Detection

    OpenAIRE

    Jellum, Marie Rennemo

    2013-01-01

    The development of wet gas compressors for installation subsea is key to increase the recovery of oil and gas from the Norwegian Continental Shelf. Safe operation of the compressor depends on understanding of how wet gas affects the behavior of the machine. The compressor operating range is limited by stall and surge, and it is therefore particularly important to determine how liquid will affect the inception of these phenomena. Measuring pressure transients within the compressor or in the in...

  17. Subsea Wet Gas Compressor Dynamics

    OpenAIRE

    Perez Aguilera, Luber Carlui

    2013-01-01

    In this Thesis the Aspen HYSYS dynamic functionalities were explored in order to build a dynamic Wet Gas Compressor model. In particular the Automation feature was used to implement two different correction methods, interpolation and Wood?s correction, that accounts for wet gas impact on compression performance, in dynamic-state. This was done through the creation of a VBA script in Microsoft Excel. The implementation of the correction methods showed to be fast and effective.The HYSYS dynamic...

  18. Reentrant Wetting of Network Fluids

    Science.gov (United States)

    Bernardino, N. R.; Telo da Gama, M. M.

    2012-09-01

    We use a simple mesoscopic Landau-Safran theory of network fluids to show that a reentrant phase diagram, in the “empty liquid” regime, leads to nonmonotonic surface tension and reentrant wetting, as previously reported for binary mixtures. One of the wetting transitions is of the usual kind, but the low temperature transition may allow the display of the full range of fluctuation regimes predicted by renormalization group theory.

  19. Transport kinetics of wetting layers

    OpenAIRE

    Herminghaus, Stephan; Paatzsch, Thomas; Häcker, T.; Leiderer, Paul

    1995-01-01

    The transport kinetics of wetting layers of ethanol and propane on silver substrates is investigated by monitoring the temporal decay of pulsed-laser-induced spatial thickness modulations. Our method allows to distinguish between different transport mechanisms, such as direct exchange with the vapour phase, viscous flow within the wetting layer, or surface diffusion. In either ease, the activation energy found for the lateral transport points to viscous flow as the dominant mechanism in the i...

  20. Wetting film dynamics and stability

    OpenAIRE

    Radoev, B.; Stoeckelhuber, K. W.; Tsekov, R.; Letocart, P

    2011-01-01

    Although the wetting films are similar in many aspects to other thin liquid films, there are some differences in their behavior, too. In contrast to soap and emulsion films, whose surfaces are homogeneous, solid substrates of wetting films are heterogeneous as a rule, unless special measures for their homogenization are taken. Here we mean primarily heterogeneous distribution of surface energy leading to existence of hydrophobic domains on hydrophilic surfaces and vice versa. As is known, suc...

  1. Wetting of polymer covered surfaces

    OpenAIRE

    Halperin, A.; De Gennes, P.G.

    1986-01-01

    We consider solid surfaces, partly covered with flexible, neutral, linear polymers (by adsorption or by grafting), wetted by a liquid which is a good solvent of the poymer. We give formulae for the spreading coefficient S as a function of chain length, solvent quality and adsorption strength. We also discuss the wetting films obtained in spreading a droplet of (non volatile) solvent : the equilibrium thickness e of the film is a compromise between S (favouring thin films) and the coil entropi...

  2. Wet Gas Compression : Impeller Rig

    OpenAIRE

    Amundsen, Siren Carstens

    2009-01-01

    Wet gas compression technology is of great value to the oil and gas industry for boosting of unprocessed well stream and to reduce investment costs related to equipment and personnel. The growing interest in wet gas compression leads to a general request for accurate performance calculation procedures and proper measurement techniques for multiphase flow metering in compressors. An impeller rig for examination of single-phase and multiphase performance and aerodynamic stability is under con...

  3. Wet flue gas desulfurization processes

    OpenAIRE

    Hayrunnisa Çavuşoğlu; Mustafa Şahin Gülaboğlu

    2013-01-01

    The wet flue gas desulfurization process is widely used for the treatment of exhaust gases in power stations. Due to its high level of effectiveness over the already available processes, it has also been the mostly preferred method by industry. Its high SO2 removal efficiency, wide applicability of absorption chemicals and the ease of the chemical process handling which does not require comprehensive konowledge are among the main advantages of this process. In this article, various wet flue g...

  4. Vanillin causes the activation of Yap1 and mitochondrial fragmentation in Saccharomyces cerevisiae.

    Science.gov (United States)

    Nguyen, Trinh Thi My; Iwaki, Aya; Ohya, Yoshikazu; Izawa, Shingo

    2014-01-01

    Vanillin and furfural are derived from lignocellulosic biomass and inhibit yeast growth and fermentation as biomass conversion inhibitors. Furfural has been shown to induce oxidative stress in Saccharomyces cerevisiae. Since there has been no report on the relationship between vanillin and oxidative stress, we investigated whether vanillin caused oxidative stress in yeast cells. We showed that vanillin caused the nuclear accumulation of Yap1, an oxidative stress responsive transcription factor, and subsequent transcriptional activation of Yap1-target genes. The growth of the null mutant of the YAP1 gene (yap1Δ) was delayed in the presence of vanillin, which indicated that Yap1 plays a role in the acquisition of tolerance to vanillin. We also demonstrated that vanillin facilitated the fragmentation of mitochondria. These findings suggest that the toxicity of vanillin involves damage induced by oxidative stress. PMID:23850265

  5. Ensiling – Wet-storage method for lignocellulosic biomass for bioethanol production

    DEFF Research Database (Denmark)

    Oleskowicz-Popiel, Piotr; Thomsen, Anne Belinda; Schmidt, Jens Ejbye

    2011-01-01

    Ensiling of humid biomass samples wrapped in plastic bales has been investigated as a wet-storage for bioethanol production from three lignocellulosic biomass samples i.e. maize, rye, and clover grass. During the silage process, lactic acid bacteria fermented free sugars to lactic acid...... of SSF (simultaneous saccharification and fermentation) were carried out using combined enzymatic hydrolysis and fermentation with two different microorganisms Saccharomyces cerevisiae and Kluyveromyces marxianus. The ethanol production was 33.0%, 27.5%, 36.9% (by K. marxianus) and 29.0%, 28.1%, 34...

  6. Production of ethanol from wet oxidised wheat straw by Thermoanaerobacter mathranii

    DEFF Research Database (Denmark)

    Ahring, B.K.; Licht, D.; Schmidt, A.S.;

    1999-01-01

    The wet oxidation process (water, oxygen, elevated temperature, sodium carbonate) was investigated as a means of solubilising hemicellulose from wheat straw. Sixteen different combinations of oxygen pressure and sodium carbonate concentration were applied. The hemicellulose hydrolysates were...

  7. Wet Deposition Concentrations and Fluxes of Mercury in Taiwan

    Science.gov (United States)

    Sheu, G.; Lin, N.

    2010-12-01

    Taiwan is located downwind to the largest anthropogenic Hg emission source region, the East Asian continent, and thus model simulations often predicted that Taiwan could receive high Hg input via wet deposition. Therefore, a mercury (Hg) wet deposition monitoring network was established in Taiwan to collect rainwater for total Hg analysis since September 2008. The objective of this network is to establish a national database of wet deposition concentrations and fluxes of Hg. This database will later be used to develop information on spatial and temporal trends in Hg wet deposition and to evaluate the contribution of regional/long-range transport. A total of 12 sampling sites, covering urban, rural, mountain, coastal and remote island areas, were set up. Weekly samples were collected using automated wet-only precipitation collection systems. Acid-cleaned glass funnels were used for rainwater collections and samples were collected into acid-cleaned 1L Teflon bottles. Samples were retrieved and sampling trains were changed every Tuesday morning. Total Hg was quantified by dual amalgamation CVAFS after BrCl oxidation, NH2OH●HCl neutralization, and SnCl2 reduction. In 2009, total Hg concentrations of all the rainwater samples ranged from 2.1 to 82.2 ng/L. Volume-weighted mean (VWM) total Hg concentrations of all the sampling sites ranged between 7.6 and 17.2 ng/L. In general, rainwater Hg concentrations were lower in northern Taiwan sites, likely due to the dilution effect caused by higher rainfall amount. Annual wet depositional Hg fluxes ranged between 12.3 and 37.0 μg/m2 in 2009, with higher values usually observed in northern Taiwan sites. The geographical distribution of wet depositional Hg flux mimicked the distribution of accumulative rainfall amount, suggesting precipitation depth is the primary factor in determining the magnitude of wet depositional Hg flux.

  8. Identification and characterization of phenylpyruvate decarboxylase genes in Saccharomyces cerevisiae.

    Science.gov (United States)

    Vuralhan, Zeynep; Morais, Marcos A; Tai, Siew-Leng; Piper, Matthew D W; Pronk, Jack T

    2003-08-01

    Catabolism of amino acids via the Ehrlich pathway involves transamination to the corresponding alpha-keto acids, followed by decarboxylation to an aldehyde and then reduction to an alcohol. Alternatively, the aldehyde may be oxidized to an acid. This pathway is functional in Saccharomyces cerevisiae, since during growth in glucose-limited chemostat cultures with phenylalanine as the sole nitrogen source, phenylethanol and phenylacetate were produced in quantities that accounted for all of the phenylalanine consumed. Our objective was to identify the structural gene(s) required for the decarboxylation of phenylpyruvate to phenylacetaldehyde, the first specific step in the Ehrlich pathway. S. cerevisiae possesses five candidate genes with sequence similarity to genes encoding thiamine diphosphate-dependent decarboxylases that could encode this activity: YDR380w/ARO10, YDL080C/THI3, PDC1, PDC5, and PDC6. Phenylpyruvate decarboxylase activity was present in cultures grown with phenylalanine as the sole nitrogen source but was absent from ammonia-grown cultures. Furthermore, the transcript level of one candidate gene (ARO10) increased 30-fold when phenylalanine replaced ammonia as the sole nitrogen source. Analyses of phenylalanine catabolite production and phenylpyruvate decarboxylase enzyme assays indicated that ARO10 was sufficient to encode phenylpyruvate decarboxylase activity in the absence of the four other candidate genes. There was also an alternative activity with a higher capacity but lower affinity for phenylpyruvate. The candidate gene THI3 did not itself encode an active phenylpyruvate decarboxylase but was required along with one or more pyruvate decarboxylase genes (PDC1, PDC5, and PDC6) for the alternative activity. The K(m) and V(max) values of the two activities differed, showing that Aro10p is the physiologically relevant phenylpyruvate decarboxylase in wild-type cells. Modifications to this gene could therefore be important for metabolic engineering

  9. Real time, in situ observation of the photocatalytic inactivation of Saccharomyces cerevisiae cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jingtao [School of Food and Bioengineering, Zhengzhou University of Light Industry, Zhengzhou 450002 (China); Environment Functional Materials Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Wang, Xiaoxin [Environment Functional Materials Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Li, Qi, E-mail: qili@imr.ac.cn [Environment Functional Materials Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Shang, Jian Ku [Environment Functional Materials Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

    2015-04-01

    An in situ microscopy technique was developed to observe in real time the photocatalytic inactivation process of Saccharomyces cerevisiae (S. cerevisiae) cells by palladium-modified nitrogen-doped titanium oxide (TiON/PdO) under visible light illumination. The technique was based on building a photocatalytic micro-reactor on the sample stage of a fluorescence/phase contrast microscopy capable of simultaneously providing the optical excitation to activate the photocatalyst in the micro-reactor and the illumination to acquire phase contrast images of the cells undergoing the photocatalytic inactivation process. Using TiON/PdO as an example, the technique revealed for the first time the vacuolar activities inside S. cerevisiae cells subjected to a visible light photocatalytic inactivation. The vacuoles responded to the photocatalytic attack by the first expansion of the vacuolar volume and then contraction, before the vacuole disappeared and the cell structure collapsed. Consistent with the aggregate behavior observed from the cell culture experiments, the transition in the vacuolar volume provided clear evidence that photocatalytic disinfection of S. cerevisiae cells started with an initiation period in which cells struggled to offset the photocatalytic damage and moved rapidly after the photocatalytic damage overwhelmed the defense mechanisms of the cells against oxidative attack. - Highlights: • Palladium-modified nitrogen-doped titanium oxidephotocatalyst (TiON/PdO) • Effective visible-light photocatalytic disinfection of yeast cells by TiON/PdO • Real time, in situ observation technique was developed for photocatalytic disinfection. • The fluorescence/phase contrast microscope with a photocatalytic micro-reactor • Yeast cell disinfection happened before the cell structure collapsed.

  10. Real time, in situ observation of the photocatalytic inactivation of Saccharomyces cerevisiae cells

    International Nuclear Information System (INIS)

    An in situ microscopy technique was developed to observe in real time the photocatalytic inactivation process of Saccharomyces cerevisiae (S. cerevisiae) cells by palladium-modified nitrogen-doped titanium oxide (TiON/PdO) under visible light illumination. The technique was based on building a photocatalytic micro-reactor on the sample stage of a fluorescence/phase contrast microscopy capable of simultaneously providing the optical excitation to activate the photocatalyst in the micro-reactor and the illumination to acquire phase contrast images of the cells undergoing the photocatalytic inactivation process. Using TiON/PdO as an example, the technique revealed for the first time the vacuolar activities inside S. cerevisiae cells subjected to a visible light photocatalytic inactivation. The vacuoles responded to the photocatalytic attack by the first expansion of the vacuolar volume and then contraction, before the vacuole disappeared and the cell structure collapsed. Consistent with the aggregate behavior observed from the cell culture experiments, the transition in the vacuolar volume provided clear evidence that photocatalytic disinfection of S. cerevisiae cells started with an initiation period in which cells struggled to offset the photocatalytic damage and moved rapidly after the photocatalytic damage overwhelmed the defense mechanisms of the cells against oxidative attack. - Highlights: • Palladium-modified nitrogen-doped titanium oxidephotocatalyst (TiON/PdO) • Effective visible-light photocatalytic disinfection of yeast cells by TiON/PdO • Real time, in situ observation technique was developed for photocatalytic disinfection. • The fluorescence/phase contrast microscope with a photocatalytic micro-reactor • Yeast cell disinfection happened before the cell structure collapsed

  11. Effects of fertilizer application and dry/wet processing of Miscanthus x giganteus on bioethanol production.

    Science.gov (United States)

    Boakye-Boaten, Nana Abayie; Xiu, Shuangning; Shahbazi, Abolghasem; Wang, Lijun; Li, Rui; Mims, Michelle; Schimmel, Keith

    2016-03-01

    The effects of wet and dry processing of miscanthus on bioethanol production using simultaneous saccharification and fermentation (SSF) process were investigated, with wet samples showing higher ethanol yields than dry samples. Miscanthus grown with no fertilizer, with fertilizer and with swine manure were sampled for analysis. Wet-fractionation was used to separate miscanthus into solid and liquid fractions. Dilute sulfuric acid pretreatment was employed and the SSF process was performed with saccharomyces cerevisiae and a cocktail of enzymes at 35°C. After pretreatment, cellulose compositions of biomass of the wet samples increased from 61.0-67.0% to 77.0-87.0%, which were higher than the compositions of dry samples. The highest theoretical ethanol yield of 88.0% was realized for wet processed pretreated miscanthus, grown with swine manure. Changes to the morphology and chemical composition of the biomass samples after pretreatment, such as crystallinity reduction, were observed using SEM and FTIR. These changes improved ethanol production. PMID:26773953

  12. TOTAL ANTIOXIDANT ACTIVITY OF YEAST SACCHAROMYCES CEREVISIAE

    Directory of Open Access Journals (Sweden)

    Blažena Lavová

    2013-02-01

    Full Text Available Antioxidants are health beneficial compounds that can protect cells and macromolecules (e.g. fats, lipids, proteins and DNA from the damage of reactive oxygen species (ROS. Sacchamomyces cerevisiae are know as organisms with very important antioxidative enzyme systems such as superoxide dismutase or catalase. The total antioxidant activity (mmol Trolox equivalent – TE.g-1 d.w. of Saccharomyces cerevisiae was measured by 2,2´-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid during the yeast cultivation. It was found that the total antioxidant activity was the highest (1.08 mmol TE.g-1 d.w. in the strain Kolín after 32 hours of cultivation and the lowest (0.26 mmol TE.g-1 d.w. in the strain Gyöng after 12 hours of cultivation.

  13. Degradation of Bagasse Alkaline Lignin by Catalytic Wet Air Oxidation with Five Catalysts%催化剂对甘蔗渣碱木质素催化湿空气氧化降解的催化作用

    Institute of Scientific and Technical Information of China (English)

    姚向荣; 詹怀宇; 周生飞

    2011-01-01

    In this paper, bagasse alkaline lignin was degraded by Catalytic Wet Air Oxidation (CWAO) with five different catalysts. The results showed that the main degradation products were; p-hydroxybenzaldehyde, vanillin, syringaldehyde, syringic acid, vanillic acid and acetosyringone. The concentration of aromatic substances increased when the reaction time increased. Catalysts had a significant effect on the concentration of aromatic substances. Using CO2O3 as catalyst, the concentration of vanillin, syringaldehyde and acetosyringone were 400.2 mg/L, 351.4 mg/L, and 248.7 mg/L respectively, and the concentration of vanillin increased 82.6% comparing to no catalyst was used. Using AQ as catalyst, the concentration of vanillin was 344. 9 mg/L which was 1. 5 times of that without using catalyst. Using Co2O3, CuSO4, MnO2, AQ, Fe2O3 as catalysts, the total concentrations of phenolic aldehyde compounds were 1696 mg/L, 1658 mg/L, 1584 mg/ L, 1347 mg/L and 1250 mg/L respectively,which explained that using Co2O3 as the catalyst was the best, and CuSO4 and MnO2 were the next, the catalysts of AQ and Fe2O3 only contributed to produce several kinds of phenolic aldehyde compounds with small molecules.%选取5种不同的催化剂对甘蔗渣碱木质素进行了催化湿空气氧化降解。结果表明,甘蔗渣碱木质素催化湿空气氧化降解的主要产物为对羟基苯甲醛、香草醛、丁香醛、丁香酸、香草酸和乙酰丁香酮;在实验条件下,反应时间对催化剂催化效果的影响较大,随着反应时间的延长,大部分小分子酚醛类化合物的浓度逐渐升高;使用催化剂能较大幅度地提高小分子酚醛类化合物的浓度。以Co2O3为催化剂,丁香醛、乙酰丁香酮、香草醛的浓度分别为400.2 mg/L、351.4 mg/L 248.7 mg/L,与未添加催化剂相比较,香草醛浓度提高了 82.6%;当以AQ为催化剂时,香草醛浓度为344.9mg/L,与空白样相比其浓度提高了1.5倍以上。

  14. Genome-scale reconstruction of the Saccharomyces cerevisiae metabolic network

    DEFF Research Database (Denmark)

    Förster, Jochen; Famili, I.; Fu, P.; Palsson, B.O.; Nielsen, Jens

    2003-01-01

    The metabolic network in the yeast Saccharomyces cerevisiae was reconstructed using currently available genomic, biochemical, and physiological information. The metabolic reactions were compartmentalized between the cytosol and the mitochondria, and transport steps between the compartments and the...... containing 1175 metabolic reactions and 584 metabolites. The number of gene functions included in the reconstructed network corresponds to similar to16% of all characterized ORFs in S. cerevisiae. Using the reconstructed network, the metabolic capabilities of S. cerevisiae were calculated and compared with...

  15. Phosphate transport and sensing in Saccharomyces cerevisiae.

    OpenAIRE

    Wykoff, D D; O'Shea, E K

    2001-01-01

    Cellular metabolism depends on the appropriate concentration of intracellular inorganic phosphate; however, little is known about how phosphate concentrations are sensed. The similarity of Pho84p, a high-affinity phosphate transporter in Saccharomyces cerevisiae, to the glucose sensors Snf3p and Rgt2p has led to the hypothesis that Pho84p is an inorganic phosphate sensor. Furthermore, pho84Delta strains have defects in phosphate signaling; they constitutively express PHO5, a phosphate starvat...

  16. Viruses and prions of Saccharomyces cerevisiae

    OpenAIRE

    Wickner, Reed B.; Fujimura, Tsutomu; Esteban, Rosa

    2013-01-01

    Saccharomyces cerevisiae has been a key experimental organism for the study of infectious diseases, including dsRNA viruses, ssRNA viruses, and prions. Studies of the mechanisms of virus and prion replication, virus structure, and structure of the amyloid filaments that are the basis of yeast prions have been at the forefront of such studies in these classes of infectious entities. Yeast has been particularly useful in defining the interactions of the infectious elements with cellular compone...

  17. Stationary phase in the yeast Saccharomyces cerevisiae.

    OpenAIRE

    Werner-Washburne, M; Braun, E.; Johnston, G C; Singer, R A

    1993-01-01

    Growth and proliferation of microorganisms such as the yeast Saccharomyces cerevisiae are controlled in part by the availability of nutrients. When proliferating yeast cells exhaust available nutrients, they enter a stationary phase characterized by cell cycle arrest and specific physiological, biochemical, and morphological changes. These changes include thickening of the cell wall, accumulation of reserve carbohydrates, and acquisition of thermotolerance. Recent characterization of mutant c...

  18. Identification of coated vesicles in Saccharomyces cerevisiae

    OpenAIRE

    1984-01-01

    Clathrin-coated vesicles were found in yeast, Saccharomyces cerevisiae, and enriched from spheroplasts by a rapid procedure utilizing gel filtration on Sephacryl S-1000. The coated vesicles (62-nm diam) were visualized by negative stain electron microscopy and clathrin triskelions were observed by rotary shadowing. The contour length of a triskelion leg was 490 nm. Coated vesicle fractions contain a prominent band with molecular weight of approximately 185,000 when analyzed by SDS PAGE. The p...

  19. Cell Wall Assembly in Saccharomyces cerevisiae

    OpenAIRE

    Lesage, Guillaume; Bussey, Howard

    2006-01-01

    An extracellular matrix composed of a layered meshwork of β-glucans, chitin, and mannoproteins encapsulates cells of the yeast Saccharomyces cerevisiae. This organelle determines cellular morphology and plays a critical role in maintaining cell integrity during cell growth and division, under stress conditions, upon cell fusion in mating, and in the durable ascospore cell wall. Here we assess recent progress in understanding the molecular biology and biochemistry of cell wall synthesis and it...

  20. Squeezing wetting and nonwetting liquids.

    Science.gov (United States)

    Samoilov, V N; Persson, B N J

    2004-01-22

    We present molecular-dynamics results for the squeezing of octane (C8H18) between two approaching solid elastic walls with different wetting properties. The interaction energy between the octane bead units and the solid walls is varied from a very small value (1 meV), corresponding to a nonwetting surface with a very large contact angle (nearly 180 degrees), to a high value (18.6 meV) corresponding to complete wetting. When at least one of the solid walls is wetted by octane we observe well defined molecular layers develop in the lubricant film when the thickness of the film is of the order of a few atomic diameters. An external squeezing-pressure induces discontinuous, thermally activated changes in the number n of lubricant layers (n-->n-1 layering transitions). With increasing interaction energy between the octane bead units and the solid walls, the transitions from n to n-1 layers occur at higher average pressure. This results from the increasing activation barrier to nucleate the squeeze-out with increasing lubricant-wall binding energy (per unit surface area) in the contact zone. Thus, strongly wetting lubricant fluids are better boundary lubricants than the less wetting ones, and this should result in less wear. We analyze in detail the effect of capillary bridge formation (in the wetting case) and droplets formation (in the nonwetting case) on the forces exerted by the lubricant on the walls. For the latter case small liquid droplets may be trapped at the interface, resulting in a repulsive force between the walls during squeezing, until the solid walls come into direct contact, where the wall-wall interaction may be initially attractive. This effect is made use of in some practical applications, and we give one illustration involving conditioners for hair care application. PMID:15268334

  1. Some specificities of wetting by cyanobiphenyl liquid crystals

    International Nuclear Information System (INIS)

    The present paper provides an up to date restatement of the wetting behaviour of the series of cyanobiphenyl liquid crystals (LCs) on usual substrates, i.e. oxidized silicon wafers, water and glycerol, at both the macroscopic and microscopic scale, in the nematic range of temperature. We show that on water the systems are close to a wetting transition, especially 5CB and 7CB. In that case, the wetting behaviour is controlled by the presence of impurities. On a mesoscopic scale, we observe for all our (thin LC film-substrate) systems an identical, complex, but well defined general scenario, not accounted for by the available models. In the last part, we present a study on line tension which results from the specific organization of LCs at the edge of the nematic film. We report preliminary results on two-dimensional film coalescence where this line tension plays a major role.

  2. Wet flue gas desulfurization processes

    Directory of Open Access Journals (Sweden)

    Hayrunnisa Çavuşoğlu

    2013-04-01

    Full Text Available The wet flue gas desulfurization process is widely used for the treatment of exhaust gases in power stations. Due to its high level of effectiveness over the already available processes, it has also been the mostly preferred method by industry. Its high SO2 removal efficiency, wide applicability of absorption chemicals and the ease of the chemical process handling which does not require comprehensive konowledge are among the main advantages of this process. In this article, various wet flue gas desulfurization processes such as lime/limestone have beendiscussed.

  3. BERYLLIUM MEASUREMENT IN COMMERCIALLY AVAILABLE WET WIPES

    Energy Technology Data Exchange (ETDEWEB)

    Youmans-Mcdonald, L.

    2011-02-18

    Analysis for beryllium by fluorescence is now an established method which is used in many government-run laboratories and commercial facilities. This study investigates the use of this technique using commercially available wet wipes. The fluorescence method is widely documented and has been approved as a standard test method by ASTM International and the National Institute for Occupational Safety and Health (NIOSH). The procedure involves dissolution of samples in aqueous ammonium bifluoride solution and then adding a small aliquot to a basic hydroxybenzoquinoline sulfonate fluorescent dye (Berylliant{trademark} Inc. Detection Solution Part No. CH-2) , and measuring the fluorescence. This method is specific to beryllium. This work explores the use of three different commercial wipes spiked with beryllium, as beryllium acetate or as beryllium oxide and subsequent analysis by optical fluorescence. The effect of possible interfering metals such as Fe, Ti and Pu in the wipe medium is also examined.

  4. Uranium recovery from wet process phosphoric acid

    International Nuclear Information System (INIS)

    Improvement in the process for recovering uranium from wetprocess phosphoric acid solution derived from the acidulation of uraniferous phosphate ores by the use of two ion exchange liquidliquid solvent extraction circuits in which in the first circuit (A) the uranium is reduced to the uranous form; (B) the uranous uranium is recovered by liquid-liquid solvent extraction using a mixture of mono- and di-(Alkyl-phenyl) esters of orthophosphoric acid as the ion exchange agent; and (C) the uranium oxidatively stripped from the agent with phosphoric acid containing an oxidizing agent to convert uranous to uranyl ions, and in the second circuit (D) recovering the uranyl uranium from the strip solution by liquid-liquid solvent extraction using di(2ethylhexyl)phosphoric acid in the presence of trioctylphosphine oxide as a synergist; (E) scrubbing the uranium loaded agent with water; (F) stripping the loaded agent with ammonium carbonate, and (G) calcining the formed ammonium uranyl carbonate to uranium oxide, the improvement comprising: (1) removing the organics from the raffinate of step (B) before recycling the raffinate to the wet-process plant, and returning the recovered organics to the circuit to substantially maintain the required balance between the mono and disubstituted esters; (2) using hydogren peroxide as the oxidizing agent in step (C); (3) using an alkali metal carbonate as the stripping agent in step (F) following by acidification of the strip solution with sulfuric acid; (4) using some of the acidified strip solution as the scrubbing agent in step (E) to remove phosphorus and other impurities; and (5) regenerating the alkali metal loaded agent from step (F) before recycling it to the second circuit

  5. Different effects of sodium chloride preincubation on cadmium tolerance of Pichia kudriavzevii and Saccharomyces cerevisiae.

    Science.gov (United States)

    Ma, Ning; Li, Chunsheng; Dong, Xiaoyan; Wang, Dongfeng; Xu, Ying

    2015-08-01

    Application of growing microorganisms for cadmium removal is restricted by high cadmium toxicity. The effects of sodium chloride (NaCl) preincubation on the cadmium tolerance and removal ability of Pichia kudriavzevii and Saccharomyces cerevisiae were investigated in this study. NaCl preincubation improved the biomass of P. kudriavzevii under cadmium stress, while no obvious effect was observed in S. cerevisiae. The improved activities of peroxidase (POD) and catalase (CAT) after NaCl preincubation might be an important reason for the decrease of the reactive oxygen species (ROS) accumulation, cell death, and oxidative damage of proteins and lipids induced by cadmium, contributing to the improvement of the yeast growth. The cadmium bioaccumulation capacity of P. kudriavzevii decreased significantly after NaCl preincubation, which played an important role in mitigating the cadmium toxicity to the yeast. The cadmium removal rate of P. kudriavzevii was obviously higher than S. cerevisiae and was significantly enhanced after NaCl preincubation. The results suggested that NaCl preincubation improved the cadmium tolerance and removal ability of P. kudriavzevii. PMID:25721585

  6. Proefproject aandachtstoffen Wet milieugevaarlijke stoffen

    OpenAIRE

    Poel P van der; Ros JPM

    1988-01-01

    Dit rapport behandelt de uitvoering van het proefproject aandachtstoffen en geeft aanbevelingen aan het DGM voor vervolgonderzoek. De aandachtstoffenlijst wordt krachtens art. 22 Wet milieugevaarlijke stoffen vastgesteld en minstens eenmaal per jaar herzien, terwijl regelmatig onderzoek uitgevoerd moet worden naar stoffen die op deze lijst voorkomen. Voor het beschreven proefproject werden schriftelijke enquetes uitgevoerd voor vertegenwoordigers uit de categorieen kleurstoffen (trypan blue),...

  7. Does Surface Roughness Amplify Wetting?

    Czech Academy of Sciences Publication Activity Database

    Malijevský, Alexandr

    2014-01-01

    Roč. 141, č. 18 (2014), s. 184703. ISSN 0021-9606 R&D Projects: GA ČR GA13-09914S Institutional support: RVO:67985858 Keywords : density functional theory * wetting * roughness Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.952, year: 2014

  8. Effects of mill stream flours technological quality on fermentative activity of baker's yeast Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Mirić Katarina V.

    2008-01-01

    Full Text Available This work in concerned with the interdependence between technological quality of mill stream flours and fermentative activity of baker's yeast Saccharomyces cerevisiae. Each mill stream flour has its own specific properties, determined by the particle size, technological phase of its formation and part of the wheat kernel it consists of. Biochemical complexity of dough during examination of fermentative activity of baker's yeast confirmed the influence of a number of physical and biochemical flour properties, such as ash content, wet gluten content, rheological flour properties, phytic acid content and amylograph peak viscosity. Abudance of significant flour characteristic, their interaction and different behavior in the presence of the yeast, showed diversity and variation of result within the same category of the mill stream flour.

  9. Converting SDAP into gypsum in a wet limestone scrubber

    Energy Technology Data Exchange (ETDEWEB)

    Fogh, F. [Faelleskemikerne, Elsamprojekt A/S, Fredericia (Denmark)

    1996-12-01

    The ELSAM power pool has an installed electrical capacity of approx. 5 GW{sub e}, mainly firing import coal. The major base load units are equipped with desulphurization units and three different desulphurization technologies are used: the wet limestone gypsum process, the spray dry absorption process and a sulphuric acid process. Gypsum and sulphuric acid are commercialized, whereas it has been difficult to utilize the spray dry absorption product (SDAP). The main constituents of SDAP are calcium sulphide, calcium chloride, hydrated lime and impurities mainly originating from fly ash. Sulphide can be oxidized into sulphate in acidic solution - the reaction is utilized in the wet limestone gypsum process - and the possibility of using any spare capacity in the wet limestone gypsum units to oxidize the sulphide content of SDAP into sulphate and produce usable gypsum has been investigated in the laboratory and in a 400 MW{sub e} equivalent wet limestone unit. The limestone inhibition effect of the addition of SDAP is currently being studied in the laboratory in order to determine the effect of different SDAP types (plant/coal sources) on limestone reactivity before further long-term full-scale tests are performed and permanent use of the process planned. (EG)

  10. Investigation of autonomous cell cycle oscillation in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Hansen, Morten Skov

    2007-01-01

    Autonome Oscillationer i kontinuert kultivering af Saccharomyces cerevisiae Udgangspunktet for dette Ph.d. projekt var at søge at forstå, hvad der gør det muligt at opnå multiple statiske tilstande ved kontinuert kultivering af Saccharomyces cerevisiae med glukose som begrænsende substrat...

  11. Kluyveromyces lactis maintains Saccharomyces cerevisiae intron-encoded splicing signals.

    OpenAIRE

    Deshler, J O; Larson, G P; Rossi, J J

    1989-01-01

    The actin (ACT) gene from the budding yeast Kluyveromyces lactis was cloned, and the nucleotide sequence was determined. The gene had a single intron 778 nucleotides in length which possessed the highly conserved splicing signals found in Saccharomyces cerevisiae introns. We demonstrated splicing of heterologous ACT transcripts in both K. lactis and S. cerevisiae.

  12. Metabolic pathway engineering for fatty acid ethyl ester production in Saccharomyces cerevisiae using stable chromosomal integration.

    Science.gov (United States)

    de Jong, Bouke Wim; Shi, Shuobo; Valle-Rodríguez, Juan Octavio; Siewers, Verena; Nielsen, Jens

    2015-03-01

    Fatty acid ethyl esters are fatty acid derived molecules similar to first generation biodiesel (fatty acid methyl esters; FAMEs) which can be produced in a microbial cell factory. Saccharomyces cerevisiae is a suitable candidate for microbial large scale and long term cultivations, which is the typical industrial production setting for biofuels. It is crucial to conserve the metabolic design of the cell factory during industrial cultivation conditions that require extensive propagation. Genetic modifications therefore have to be introduced in a stable manner. Here, several metabolic engineering strategies for improved production of fatty acid ethyl esters in S. cerevisiae were combined and the genes were stably expressed from the organisms' chromosomes. A wax ester synthase (ws2) was expressed in different yeast strains with an engineered acetyl-CoA and fatty acid metabolism. Thus, we compared expression of ws2 with and without overexpression of alcohol dehydrogenase (ADH2), acetaldehyde dehydrogenase (ALD6) and acetyl-CoA synthetase (acs SE (L641P) ) and further evaluated additional overexpression of a mutant version of acetyl-CoA decarboxylase (ACC1 (S1157A,S659A) ) and the acyl-CoA binding protein (ACB1). The combined engineering efforts of the implementation of ws2, ADH2, ALD6 and acs SE (L641P) , ACC1 (S1157A,S659A) and ACB1 in a S. cerevisiae strain lacking storage lipid formation (are1Δ, are2Δ, dga1Δ and lro1Δ) and β-oxidation (pox1Δ) resulted in a 4.1-fold improvement compared with sole expression of ws2 in S. cerevisiae. PMID:25422103

  13. Effects of spaceflight on polysaccharides of Saccharomyces cerevisiae cell wall.

    Science.gov (United States)

    Liu, Hong-Zhi; Wang, Qiang; Liu, Xiao-Yong; Tan, Sze-Sze

    2008-12-01

    Freeze-dried samples of four Saccharomyces cerevisiae strains, namely, FL01, FL03, 2.0016, and 2.1424, were subjected to spaceflight. After the satellite's landing on Earth, the samples were recovered and changes in yeast cell wall were analyzed. Spaceflight strains of all S. cerevisiae strains showed significant changes in cell wall thickness (P growth curve analysis showed spaceflight S. cerevisiae 2.0016 had a faster growth rate, shorter lag phase periods, higher final biomass, and higher content of beta-glucan. Genetic stability analysis showed that prolonged subculturing of spaceflight strain S. cerevisiae 2.0016 did not lead to the appearance of variants, indicating that the genetic stability of S. cerevisiae 2.0016 mutant could be sufficient for its exploitation of beta-glucan production. PMID:18797865

  14. A novel role for DNA photolyase: binding to DNA damaged by drugs is associated with enhanced cytotoxicity in Saccharomyces cerevisiae.

    OpenAIRE

    Fox, M E; Feldman, B. J.; Chu, G.

    1994-01-01

    DNA photolyase binds to and repairs cyclobutane pyrimidine dimers induced by UV radiation. Here we demonstrate that in the yeast Saccharomyces cerevisiae, photolyase also binds to DNA damaged by the anticancer drugs cis-diamminedichloroplatinum (cis-DDP) and nitrogen mustard (HN2) and by the alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Surprisingly, mutations in photolyase were associated with resistance of yeast cells to cis-DDP, MNNG, 4-nitroquinoline oxide (4NQO), and HN2....

  15. The ATX1 gene of Saccharomyces cerevisiae encodes a small metal homeostasis factor that protects cells against reactive oxygen toxicity.

    OpenAIRE

    Lin, S J; Culotta, V C

    1995-01-01

    In aerobic organisms, protection against oxidative damage involves the combined action of highly specialized antioxidant enzymes, such as superoxide dismutase (SOD) and catalase. Here we describe the isolation and characterization of another gene in the yeast Saccharomyces cerevisiae that plays a critical role in detoxification of reactive oxygen species. This gene, named ATX1, was originally isolated by its ability to suppress oxygen toxicity in yeast lacking SOD. ATX1 encodes a 8.2-kDa poly...

  16. Metabolic alterations during ascosporogenesis of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Sporulation of S. cerevisiae has been shown to alter the profiles of enzymes involved in gluconeogenesis and glycolysis. The enhancement in the levels of total cellular carbohydrates could be correlated with the enhancement in fructose 1,6-diphosphatase and trehalose-phosphate synthetase. The latter activity could account for the 15-fold increase in trehalose levels in sporulating cells. Glucose-6-phosphatase, pyruvate kinase and phosphofructokinase showed continuous decline during ascosporogenesis. The relative incorporation of radioactivity from possible precursors of gluconeogenesis indicated that acetate-2-14C alone could contribute to carbohydrate synthesis. (author)

  17. Anethole induces apoptotic cell death accompanied by reactive oxygen species production and DNA fragmentation in Aspergillus fumigatus and Saccharomyces cerevisiae.

    Science.gov (United States)

    Fujita, Ken-Ichi; Tatsumi, Miki; Ogita, Akira; Kubo, Isao; Tanaka, Toshio

    2014-02-01

    trans-Anethole (anethole), a major component of anise oil, has a broad antimicrobial spectrum, and antimicrobial activity that is weaker than that of other antibiotics on the market. When combined with polygodial, nagilactone E, and n-dodecanol, anethole has been shown to possess significant synergistic antifungal activity against a budding yeast, Saccharomyces cerevisiae, and a human opportunistic pathogenic yeast, Candida albicans. However, the antifungal mechanism of anethole has not been completely determined. We found that anethole stimulated cell death of a human opportunistic pathogenic fungus, Aspergillus fumigatus, in addition to S. cerevisiae. The anethole-induced cell death was accompanied by reactive oxygen species production, metacaspase activation, and DNA fragmentation. Several mutants of S. cerevisiae, in which genes related to the apoptosis-initiating execution signals from mitochondria were deleted, were resistant to anethole. These results suggest that anethole-induced cell death could be explained by oxidative stress-dependent apoptosis via typical mitochondrial death cascades in fungi, including A. fumigatus and S. cerevisiae. PMID:24393541

  18. Increasing NADH oxidation reduces overflow metabolism in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Vemuri, Goutham; Eiteman, M.A; McEwen, J.E;

    2007-01-01

    Respiratory metabolism plays an important role in energy production in the form of ATP in all aerobically growing cells. However, a limitation in respiratory capacity results in overflow metabolism, leading to the formation of byproducts, a phenomenon known as ‘‘overflow metabolism’’ or ‘‘the Cra...

  19. Improved hydrogen sorption kinetics in wet ball milled Mg hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Li

    2011-05-04

    In this work, wet ball milling method is used in order to improve hydrogen sorption behaviour due to its improved microstructure of solid hydrogen materials. Compared to traditional ball milling method, wet ball milling has benefits on improvement of MgH{sub 2} microstructure and further influences on its hydrogen sorption behavior. With the help of solvent tetrahydrofuran (THF), wet ball milled MgH{sub 2} powder has much smaller particle size and its specific surface area is 7 times as large as that of dry ball milled MgH{sub 2} powder. Although after ball milling the grain size is decreased a lot compared to as-received MgH{sub 2} powder, the grain size of wet ball milled MgH{sub 2} powder is larger than that of dry ball milled MgH{sub 2} powder due to the lubricant effect of solvent THF during wet ball milling. The improved particle size and specific surface area of wet ball milled MgH{sub 2} powder is found to be determining its hydrogen sorption kinetics especially at relatively low temperatures. And it also shows good cycling sorption behavior, which decides on its industrial applicability. With three different catalysts MgH{sub 2} powder shows improved hydrogen sorption behavior as well as the cyclic sorption behavior. Among them, the Nb{sub 2}O{sub 5} catalyst is found to be the most effective one in this work. Compared to the wet ball milled MgH{sub 2} powder, the particle size and specific surface area of the MgH{sub 2} powder with catalysts are similar to the previous ones, while the grain size of the MgH{sub 2} with catalysts is much finer. In this case, two reasons for hydrogen sorption improvement are suggested: one is the reduction of the grain size. The other may be as pointed out in some literatures that formation of new oxidation could enhance the hydrogen sorption kinetics, which is also the reason why its hydrogen capacity is decreased compared to without catalysts. After further ball milling, the specific surface area of wet ball milled Mg

  20. WET SOLIDS FLOW ENHANCEMENT; FINAL

    International Nuclear Information System (INIS)

    The yield locus, tensile strength and fracture mechanisms of wet granular materials were studied. The yield locus of a wet material was shifted to the left of that of the dry specimen by a constant value equal to the compressive isostatic stress due to pendular bridges. for materials with straight yield loci, the shift was computed from the uniaxial tensile strength, either measured in a tensile strength tester or calculated from the correlation, and the angle of internal friction of the material. The predicted shift in the yield loci due to different moisture contents compare well with the measured shift in the yield loci of glass beads, crushed limestone, super D catalyst and Leslie coal. Measurement of the void fraction during the shear testing was critical to obtain the correct tensile strength theoretically or experimentally

  1. Biosorption of cesium by saccharomyces cerevisia

    International Nuclear Information System (INIS)

    The characteristics of Cs+ biosorption by Saccharornyces cerevisia was investigated, including the biosorption kinetics, biosorption equilibrium, isotherm as well as the IR spectrum of biomass pre- and post-biosorption. The experimental results show that the process of Cs+ biosorption onto the biomass of Saccharornyces cerevisia can be devided into two stages, the first stage is physical sorption and the sorption equilibrium is very quickly reached (within 20 min). The biosorption kinetics can be described by the pseudo second-order equation quite well (R2=0.989), the kinetic parameters k2 and qe are 3.56 x 10-3 g/(mg·min) and 7.18 mg/g, respectively. The equilibrium isotherm data can be fitted with Langmuir and Freundlich models, with the maximum biosorptive capacity of 10.13 mg/g. Both the IR spectra of the biomass pre- and post-biosorption almost are same, and it indicates that the biosorption of Cs+ does not change the structure of the biomass, however, some adsorptive peaks shift. (authors)

  2. Heterooligomeric phosphoribosyl diphosphate synthase of Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Hove-Jensen, Bjarne

    2004-01-01

    The yeast Saccharomyces cerevisiae contains five phosphoribosyl diphosphate (PRPP) synthase-homologous genes (PRS1-5), which specify PRPP synthase subunits 1-5. Expression of the five S. cerevisiae PRS genes individually in an Escherichia coli PRPP-less strain (Deltaprs) showed that a single PRS...... gene product had no PRPP synthase activity. In contrast, expression of five pairwise combinations of PRS genes resulted in the formation of active PRPP synthase. These combinations were PRS1 PRS2, PRS1 PRS3, and PRS1 PRS4, as well as PRS5 PRS2 and PRS5 PRS4. None of the remaining five possible pairwise...... combinations of PRS genes appeared to produce active enzyme. Extract of an E. coli strain containing a plasmid-borne PRS1 gene and a chromosome-borne PRS3 gene contained detectable PRPP synthase activity, whereas extracts of strains containing PRS1 PRS2, PRS1 PRS4, PRS5 PRS2, or PRS5 PRS4 contained no...

  3. Response of Saccharomyces cerevisiae to cadmium stress

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Luciana Mara Costa; Ribeiro, Frederico Haddad; Neves, Maria Jose [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Lab. de Radiobiologia], e-mail: luamatu@uol.com.br; Porto, Barbara Abranches Araujo; Amaral, Angela M.; Menezes, Maria Angela B.C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Lab. de Ativacao Neutronica], e-mail: menezes@cdtn.br; Rosa, Carlos Augusto [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Microbiologia], e-mail: carlrosa@icb.ufmg

    2009-07-01

    The intensification of industrial activity has been greatly contributing with the increase of heavy metals in the environment. Among these heavy metals, cadmium becomes a serious pervasive environmental pollutant. The cadmium is a heavy metal with no biological function, very toxic and carcinogenic at low concentrations. The toxicity of cadmium and several other metals can be mainly attributed to the multiplicity of coordination complexes and clusters that they can form. Some aspects of the cellular response to cadmium were extensively investigated in the yeast Saccharomyces cerevisiae. The primary site of interaction between many toxic metals and microbial cells is the plasma membrane. Plasma-membrane permeabilisation has been reported in a variety of microorganisms following cadmium exposure, and is considered one mechanism of cadmium toxicity in the yeast. In this work, using the yeast strain S. cerevisiae W303-WT, we have investigated the relationships between Cd uptake and release of cellular metal ions (K{sup +} and Na{sup +}) using neutron activation technique. The neutron activation was an easy, rapid and suitable technique for doing these metal determinations on yeast cells; was observed the change in morphology of the strains during the process of Cd accumulation, these alterations were observed by Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) during incorporation of cadmium. (author)

  4. Review of Wet Gas Compressor Performance

    OpenAIRE

    Rofiqi, Zaenuddin Ar

    2014-01-01

    Subsea wet gas compression without preliminary separation give an opportunity to develop mature and remote gas/condensate field. Predicting wet gas compressor performance is important to develop those fields. Currently there is no standard exist for wet gas compression performance calculation (Hundseid et al., 2008). The current standards (ISO 5389:2005) exist only for dry gas by utilizing Schultz method. In wet gas compression, fluid properties are changing as fluid being compressed. Schult...

  5. Xylose Fermentation by Saccharomyces cerevisiae: Challenges and Prospects

    Directory of Open Access Journals (Sweden)

    Danuza Nogueira Moysés

    2016-02-01

    Full Text Available Many years have passed since the first genetically modified Saccharomyces cerevisiae strains capable of fermenting xylose were obtained with the promise of an environmentally sustainable solution for the conversion of the abundant lignocellulosic biomass to ethanol. Several challenges emerged from these first experiences, most of them related to solving redox imbalances, discovering new pathways for xylose utilization, modulation of the expression of genes of the non-oxidative pentose phosphate pathway, and reduction of xylitol formation. Strategies on evolutionary engineering were used to improve fermentation kinetics, but the resulting strains were still far from industrial application. Lignocellulosic hydrolysates proved to have different inhibitors derived from lignin and sugar degradation, along with significant amounts of acetic acid, intrinsically related with biomass deconstruction. This, associated with pH, temperature, high ethanol, and other stress fluctuations presented on large scale fermentations led the search for yeasts with more robust backgrounds, like industrial strains, as engineering targets. Some promising yeasts were obtained both from studies of stress tolerance genes and adaptation on hydrolysates. Since fermentation times on mixed-substrate hydrolysates were still not cost-effective, the more selective search for new or engineered sugar transporters for xylose are still the focus of many recent studies. These challenges, as well as under-appreciated process strategies, will be discussed in this review.

  6. Xylose Fermentation by Saccharomyces cerevisiae: Challenges and Prospects.

    Science.gov (United States)

    Moysés, Danuza Nogueira; Reis, Viviane Castelo Branco; de Almeida, João Ricardo Moreira; de Moraes, Lidia Maria Pepe; Torres, Fernando Araripe Gonçalves

    2016-01-01

    Many years have passed since the first genetically modified Saccharomyces cerevisiae strains capable of fermenting xylose were obtained with the promise of an environmentally sustainable solution for the conversion of the abundant lignocellulosic biomass to ethanol. Several challenges emerged from these first experiences, most of them related to solving redox imbalances, discovering new pathways for xylose utilization, modulation of the expression of genes of the non-oxidative pentose phosphate pathway, and reduction of xylitol formation. Strategies on evolutionary engineering were used to improve fermentation kinetics, but the resulting strains were still far from industrial application. Lignocellulosic hydrolysates proved to have different inhibitors derived from lignin and sugar degradation, along with significant amounts of acetic acid, intrinsically related with biomass deconstruction. This, associated with pH, temperature, high ethanol, and other stress fluctuations presented on large scale fermentations led the search for yeasts with more robust backgrounds, like industrial strains, as engineering targets. Some promising yeasts were obtained both from studies of stress tolerance genes and adaptation on hydrolysates. Since fermentation times on mixed-substrate hydrolysates were still not cost-effective, the more selective search for new or engineered sugar transporters for xylose are still the focus of many recent studies. These challenges, as well as under-appreciated process strategies, will be discussed in this review. PMID:26927067

  7. Xylose Fermentation by Saccharomyces cerevisiae: Challenges and Prospects

    Science.gov (United States)

    Moysés, Danuza Nogueira; Reis, Viviane Castelo Branco; de Almeida, João Ricardo Moreira; de Moraes, Lidia Maria Pepe; Torres, Fernando Araripe Gonçalves

    2016-01-01

    Many years have passed since the first genetically modified Saccharomyces cerevisiae strains capable of fermenting xylose were obtained with the promise of an environmentally sustainable solution for the conversion of the abundant lignocellulosic biomass to ethanol. Several challenges emerged from these first experiences, most of them related to solving redox imbalances, discovering new pathways for xylose utilization, modulation of the expression of genes of the non-oxidative pentose phosphate pathway, and reduction of xylitol formation. Strategies on evolutionary engineering were used to improve fermentation kinetics, but the resulting strains were still far from industrial application. Lignocellulosic hydrolysates proved to have different inhibitors derived from lignin and sugar degradation, along with significant amounts of acetic acid, intrinsically related with biomass deconstruction. This, associated with pH, temperature, high ethanol, and other stress fluctuations presented on large scale fermentations led the search for yeasts with more robust backgrounds, like industrial strains, as engineering targets. Some promising yeasts were obtained both from studies of stress tolerance genes and adaptation on hydrolysates. Since fermentation times on mixed-substrate hydrolysates were still not cost-effective, the more selective search for new or engineered sugar transporters for xylose are still the focus of many recent studies. These challenges, as well as under-appreciated process strategies, will be discussed in this review. PMID:26927067

  8. Wetting hysteresis induced by nanodefects.

    Science.gov (United States)

    Giacomello, Alberto; Schimmele, Lothar; Dietrich, Siegfried

    2016-01-19

    Wetting of actual surfaces involves diverse hysteretic phenomena stemming from ever-present imperfections. Here, we clarify the origin of wetting hysteresis for a liquid front advancing or receding across an isolated defect of nanometric size. Various kinds of chemical and topographical nanodefects, which represent salient features of actual heterogeneous surfaces, are investigated. The most probable wetting path across surface heterogeneities is identified by combining, within an innovative approach, microscopic classical density functional theory and the string method devised for the study of rare events. The computed rugged free-energy landscape demonstrates that hysteresis emerges as a consequence of metastable pinning of the liquid front at the defects; the barriers for thermally activated defect crossing, the pinning force, and hysteresis are quantified and related to the geometry and chemistry of the defects allowing for the occurrence of nanoscopic effects. The main result of our calculations is that even weak nanoscale defects, which are difficult to characterize in generic microfluidic experiments, can be the source of a plethora of hysteretical phenomena, including the pinning of nanobubbles. PMID:26721395

  9. Wet water glass production plant

    Directory of Open Access Journals (Sweden)

    Stanković Mirjana S.

    2003-01-01

    Full Text Available The IGPC Engineering Department designed basic projects for a wet hydrate dissolution plant, using technology developed in the IGPC laboratories. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant of a capacity of 75,000 t/y was manufactured, at "Zeolite Mira", Mira (VE, Italy, in 1997. and 1998, increasing detergent zeolite production, from 50,000 to 100,000 t/y. Several goals were realized by designing a wet hydrate dissolution plant. The main goal was increasing the detergent zeolite production. The technological cycle of NaOH was closed, and no effluents emitted, and there is no pollution (except for the filter cake. The wet water glass production process is fully automatized, and the product has uniform quality. The production process can be controlled manually, which is necessary during start - up, and repairs. By installing additional process equipment (centrifugal pumps and heat exchangers technological bottlenecks were overcome, and by adjusting the operation of autoclaves, and water glass filters and also by optimizing the capacities of process equipment.

  10. Wet friction materials and lubricants

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Takayuki

    1988-02-01

    There are wet and dry friction materials used for friction clutches and friction brakes. Wet friction materials include sintered alloys and semimetallic substances. Paper friction materials which are the most common wet friction materials used in automobiles were studied for their performance and their relation to lubricants. All present paper friction materials are non-asbestos paper friction materials. The requirements for paper friction material performance are as follows: (1) The heat resistance and durability are so high that the material can stand sliding for a long time. (2) The friction curve is flat. (3) The mechanical strength, wear resistance, and resistance to oil pressure are high. (4) The coefficient of friction (particularly, of static friction) is very high. (5) Variations in the coefficient of friction with time are low. The friction characteristics and wear of paper friction materials are influenced by the lubricant used together with the paper friction materials. It is necessary to develop materials which are immune to the influence of the lubricant. (11 figs, 3 tabs, 21 refs)

  11. Study of wet blasting of components in nuclear power stations

    International Nuclear Information System (INIS)

    This report looks at the method of wet blasting radioactive components in nuclear power stations. The wet blaster uses pearl shaped glass beads with the dimensions of 150-250 μm mixed with water as blasting media. The improved design, providing outer operator's positions with proper radiation protection and more efficient blasting equipment has resulted in a lesser dose taken by the operators. The main reason to decontaminate components in nuclear power plants is to enable service on these components. On components like valves, pump shafts, pipes etc. oxides form and bind radiation. These components are normally situated at some distance from the reactor core and will mainly suffer from radiation from so called activation products. When a component is to be decontaminated it can be decontaminated to a radioactive level where it will be declassified. This report has found levels ranging from 150-1000 Bq/kg allowing declassification of radioactive materials. This difference is found between different countries and different organisations. The report also looks at the levels of waste generated using wet blasting. This is done by tracking the contamination to determine where it collects. It is either collected in the water treatment plant or collected in the blasting media. At Barsebaeck the waste levels, from de-contaminating nearly 800 components in one year, results in a waste volume of about 0,250 m3. This waste consists of low and medium level waste and will cost about 3 600 EURO to store. The conclusions of the report are that wet blasting is an indispensable way to treat contaminated components in modern nuclear power plants. The wet blasting equipment can be improved by using a robot enabling the operators to remotely treat components from the outer operator's positions. There they will benefit from better radiation protection thus further reduce their taken dose. The wet blasting equipment could also be used to better control the levels of radioactivity on

  12. Evidence for Domesticated and Wild Populations of Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    2005-07-01

    Full Text Available Saccharomyces cerevisiae is predominantly found in association with human activities, particularly the production of alcoholic beverages. S. paradoxus, the closest known relative of S. cerevisiae, is commonly found on exudates and bark of deciduous trees and in associated soils. This has lead to the idea that S. cerevisiae is a domesticated species, specialized for the fermentation of alcoholic beverages, and isolates of S. cerevisiae from other sources simply represent migrants from these fermentations. We have surveyed DNA sequence diversity at five loci in 81 strains of S. cerevisiae that were isolated from a variety of human and natural fermentations as well as sources unrelated to alcoholic beverage production, such as tree exudates and immunocompromised patients. Diversity within vineyard strains and within saké strains is low, consistent with their status as domesticated stocks. The oldest lineages and the majority of variation are found in strains from sources unrelated to wine production. We propose a model whereby two specialized breeds of S. cerevisiae have been created, one for the production of grape wine and one for the production of saké wine. We estimate that these two breeds have remained isolated from one another for thousands of years, consistent with the earliest archeological evidence for winemaking. We conclude that although there are clearly strains of S. cerevisiae specialized for the production of alcoholic beverages, these have been derived from natural populations unassociated with alcoholic beverage production, rather than the opposite.

  13. 1 - Aromatization of n-hexane and natural gasoline over ZSM-5 zeolite, 2- Wet catalytic oxidation of phenol on fixed bed of active carbon; 1 - Aromatisation de n-hexane et d'essence sur zeolithe ZSM-5, 2 - Oxydation catalytique en voie humide du phenol sur charbon actif

    Energy Technology Data Exchange (ETDEWEB)

    Suwanprasop, S.

    2005-04-15

    I - The production of aromatic hydrocarbons from n-hexane and natural gasoline over Pd loaded ZSM-5 zeolite in a tubular reactor was achieved under the suitable conditions at 400 deg. C, and 0.4 ml/min reactant feeding rate, employing ZSM-5 (0.5% Pd content) as a catalyst. Under these conditions, n-hexane and natural gasoline conversions were found to be 99.7% and 94.3%, respectively (with respective aromatic selectivity of 92.3% and 92.6%). II - Wet catalytic air oxidation of phenol over a commercial active carbon was studied in a three phase fixed bed reactor under mild temperature and oxygen partial pressure. Exit phenol concentration, COD, and intermediates were analysed. Oxidation of phenol was significantly improved when increasing operating temperature, oxygen partial pressure, and liquid space time, while up or down flow modes had only marginal effect. A complete model involving intrinsic kinetics and all mass transfer limitations gave convenient reactor simulation. (author)

  14. Inhibition of corrosive processes in wet atmosphere

    International Nuclear Information System (INIS)

    Toluylalanine (TALA) is an additive in industrial cleaning baths and an effective temporary inhibitor of the corrosion of steel in neutral and weak alkaline electrolytes as well as in wet atmosphere. In dependence on the relative humidity of the atmosphere and the presence of hygroscopic salts, thin water films condense. The interaction between the metallic surface and the condensed liquid depends strongly on the surface tension. In our case we obtained a hydrophilic effect after the adsorption of the inhibitor. It can be assumed, that the water of the cleaning bath drains off the metal much better than in the case of hydrophobic layers. These effects in the range of monolayers could be studied with the quartz microbalance due to the high sensitivity of this technique. Improving our model, we obtained a lower and homogenous deposition of salt after the dipping in solution with TALA, which causes also a reduced homogenous condensation of water. Thus, corrosive attacks become less probable. The reactions in the cleaning bath and in films of condensed water were investigated by electrochemical methods in bulk electrolytes. In the presence of inhibitor the corrosion potential was shifted into the anodic direction, simultaneously the thickness of the oxide layer was increased in the presence of TALA. The characteristic data of pitting corrosion were obtained from anodic potentiodynamic sweeps. These results show, that pitting is hindered by TALA. Besides the stabilization of the passive layer, the growth of pits is also inhibited and repassivation is accelerated. From the polarization of probes precorroded at wet atmosphere we yielded in solutions with TALA an re-inhibition, too. Additionally we observed in unprotected solutions the sensitivity of this method to active corrosion centers, which cause pitting at lower overvoltages

  15. The surface state of hematite and its wetting characteristics.

    Science.gov (United States)

    Shrimali, Kaustubh; Jin, Jiaqi; Hassas, Behzad Vaziri; Wang, Xuming; Miller, Jan D

    2016-09-01

    Apart from being a resource for iron/steel production, the iron oxide minerals, goethite and hematite, are used in the paint, cosmetics, and other industries as pigments. Surface characteristics of these minerals have been studied extensively both in resource recovery by flotation and in the preparation of colloidal dispersions. In this current research, the wetting characteristics of goethite (FeOOH) and hematite (Fe2O3) have been analyzed by means of contact angle, bubble attachment time, and Atomic Force Microscopy (AFM) measurements as well as by Molecular Dynamics Simulation (MDS). Goethite is naturally hydroxylated and wetted by water at all pH values. In contrast, the anhydrous hematite surface (001) was found to be slightly hydrophobic at natural pH values with a contact angle of about 50°. At alkaline pH hydroxylation of the hematite surface occurs rapidly and the hematite becomes hydrophilic. The wetting characteristics of the hematite surface then vary between the hydrophobic anhydrous hematite and the completely hydrophilic hydroxylated hematite, similar to goethite. The hydrophobicity can be restored by heating of the hydroxylated hematite surface at 60°C. The hydrophobic character of the anhydrous hematite (001) surface is confirmed by MDS which also reveals that after hydrolysis the hematite (001) surface can be wetted by water, similar to the goethite (001) surface. PMID:27236840

  16. Precursor films in wetting phenomena

    OpenAIRE

    Popescu, M. N.; Oshanin, G.; Dietrich, S.; Cazabat, A. -M.

    2012-01-01

    The spontaneous spreading of non-volatile liquid droplets on solid substrates poses a classic problem in the context of wetting phenomena. It is well known that the spreading of a macroscopic droplet is in many cases accompanied by a thin film of macroscopic lateral extent, the so-called precursor film, which emanates from the three-phase contact line region and spreads ahead of the latter with a much higher speed. Such films have been usually associated with liquid-on-solid systems, but in t...

  17. Experimental Investigation and Modelling of a Wet Flue Gas Desulphurisation Pilot Plant

    DEFF Research Database (Denmark)

    Kiil, Søren; Michelsen, Michael Locht; Dam-Johansen, Kim

    1998-01-01

    A detailed model for a wet flue gas desulphurisation (FGD) pilot plant, based on the packed tower concept, has been developed. All important rate determining steps, absorption of SO2, oxidation of HSO3-, dissolution of limestone, and crystallisation of gypsum were included. Population balance...... limestone in the gypsum. Simulations were found to match experimental data for the two limestone types investigated. A parameter study of the model was conducted with the purpose of validating assumptions and extracting information on wet FGD systems. The modelling tools developed may be applicable to other...... wet FGD plants....

  18. Probing glycolytic and membrane potential oscillations in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Poulsen, Allan K.; Andersen, Ann Zahle; Brasen, Jens Christian; Scharff-Poulsen, Anne Marie; Olsen, Lars Folke

    2008-01-01

    We have investigated glycolytic oscillations under semi-anaerobic conditions in Saccharomyces cerevisiae by means of NADH fluorescence, measurements of intracellular glucose concentration, and mitochondrial membrane potential. The glucose concentration was measured using an optical nanosensor...

  19. Evolutionary engineering of Saccharomyces cerevisiae for efficient aerobic xylose consumption

    DEFF Research Database (Denmark)

    Scalcinati, Gionata; Otero, José Manuel; Van Vleet, Jennifer R. H.;

    2012-01-01

    flux to biomass production. Such a platform may then be enhanced with complementary metabolic engineering strategies that couple biomass production with high value-added chemical. Saccharomyces cerevisiae, expressing xylose reductase, xylitol dehydrogenase and xylulose kinase, from the native xylose...

  20. Rapid Development of Wet Adhesion between Carboxymethylcellulose Modified Cellulose Surfaces Laminated with Polyvinylamine Adhesive.

    Science.gov (United States)

    Gustafsson, Emil; Pelton, Robert; Wågberg, Lars

    2016-09-14

    The surface of regenerated cellulose membranes was modified by irreversible adsorption of carboxymethylcellulose (CMC). Pairs of wet CMC-modified membranes were laminated with polyvinylamine (PVAm) at room temperature, and the delamination force for wet membranes was measured for both dried and never-dried laminates. The wet adhesion was studied as a function of PVAm molecular weight, amine content, and deposition pH of the polyelectrolyte. Surprisingly the PVAm-CMC system gave substantial wet adhesion that exceeded that of TEMPO-oxidized membranes with PVAm for both dried and never-dried laminates. The greatest wet adhesion was achieved for fully hydrolyzed high molecular weight PVAm. Bulk carboxymethylation of cellulose membranes gave inferior wet adhesion combined with PVAm as compared to CMC adsorption which indicates that a CMC layer of the order of 10 nm was necessary. There are no obvious covalent cross-linking reactions between CMC and PVAm at room temperature, and on the basis of our results, we are instead attributing the wet adhesion to complex formation between the PVAm and the irreversibly adsorbed CMC at the cellulose surface. We propose that interdigitation of PVAm chains into the CMC layer is responsible for the high wet adhesion values. PMID:27552256

  1. Biosorption of 241Am by immobilized Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Americium-241 is one of the most serious radioactive contaminating nuclides due to its high toxicity and long half-life. The encouraging biosorption of 241Am from aqueous solutions by free Saccharomyces cerevisiae (S. cerevisiae) has been observed in our previous experiments. 241Am biosorption by immobilized S. cerevisiae and the effect of the various experimental conditions on the adsorption were investigated. The results indicated that the 241Am biosorption by immobilized S. cerevisiae is still very efficient, and immobilized S. cerevisiae can be used repeatedly or continuously. The biosorption equilibrium was achieved within 2 hours, and more than 92% of 241Am was removed by immobilized S. cerevisiae in the pH 1-4 range. No significant differences in 241Am biosorption were observed at 15-45 deg C. The immobilized S. cerevisiae, even after used repeatedly for 6 times, still could adsorb more than 90% of 241Am in solutions of 1.08 MBq/l (8.5 μg/l). At this moment, the total adsorption capacity for 241Am was more than 63.3 KBq/g globe (0.5 μg/g), but has not reached saturation yet. The 241Am left in solutions with initial concentration of 1.08 MBq/l (8.5 μg/l) was noted as low as ∼10 Bq/l (∼8.0 x 10-5 μg/l) after adsorption by the immobilized S. cerevisiae for 3 times. (author)

  2. Research on biosorption of uranium by saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    The effects of pH and the granularity of S. cerevisiae on the biosorption capacity were examined in order to study the properties of the biosorption of uranium from effluent by Saccharomyces cerevisiae. The isotherm was drawn. From the isotherm, the equations of Langmuir and Freundlich were achieved. The results showed the highest biosorption capacity was obtained when the pH value was about 6 and the granularity was 0.15-0.13 mm

  3. Glucose- and nitrogen sensing and regulatory mechanisms in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Rødkaer, Steven V; Færgeman, Nils J.

    2014-01-01

    steps and by numerous different regulators. As numerous of these regulating proteins, biochemical mechanisms, and cellular pathways are evolutionary conserved, complex biochemical information relevant to humans can be obtained by studying simple organisms. Thus, the yeast Saccharomyces cerevisiae has...... been recognized as a powerful model system to study fundamental biochemical processes. In the present review, we highlight central signaling pathways and molecular circuits conferring nitrogen- and glucose sensing in S. cerevisiae....

  4. Recovery of Saccharomyces cerevisiae from ethanol-induced growth inhibition.

    OpenAIRE

    Walker-Caprioglio, H M; Rodriguez, R J; Parks, L. W.

    1985-01-01

    Ethanol caused altered mobility of the lipophilic probe 1,6-diphenyl-1,3,5-hexatriene in plasma membrane preparations of Saccharomyces cerevisiae. Because lipids had been shown to protect yeast cells against ethanol toxicity, sterols, fatty acids, proteins, and combinations of these were tested; however, protection from growth inhibition was not seen. Ethanol-induced, prolonged lag periods and diminished growth rates in S. cerevisiae were reduced by an autoconditioning of the medium by the in...

  5. Isolation, identification and characterization of regional indigenous Saccharomyces cerevisiae strains

    OpenAIRE

    Hana Šuranská; Dana Vránová; Jiřina Omelková

    2016-01-01

    Abstract In the present work we isolated and identified various indigenous Saccharomyces cerevisiae strains and screened them for the selected oenological properties. These S. cerevisiae strains were isolated from berries and spontaneously fermented musts. The grape berries (Sauvignon blanc and Pinot noir) were grown under the integrated and organic mode of farming in the South Moravia (Czech Republic) wine region. Modern genotyping techniques such as PCR-fingerprinting and interdelta PCR typ...

  6. Isolation, identification and characterization of regional indigenous Saccharomyces cerevisiae strains

    OpenAIRE

    Šuranská, Hana; Vránová, Dana; Omelková, Jiřina

    2016-01-01

    In the present work we isolated and identified various indigenous Saccharomyces cerevisiae strains and screened them for the selected oenological properties. These S. cerevisiae strains were isolated from berries and spontaneously fermented musts. The grape berries (Sauvignon blanc and Pinot noir) were grown under the integrated and organic mode of farming in the South Moravia (Czech Republic) wine region. Modern genotyping techniques such as PCR-fingerprinting and interdelta PCR typing were ...

  7. Elucidating the mysteries of wetting.

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Edmund Blackburn, III (,; ); Bourdon, Christopher Jay; Grillet, Anne Mary; Sackinger, Philip A.; Grest, Gary Stephen; Emerson, John Allen; Ash, Benjamin Jesse; Heine, David R.; Brooks, Carlton, F.; Gorby, Allen D.

    2005-11-01

    Nearly every manufacturing and many technologies central to Sandia's business involve physical processes controlled by interfacial wetting. Interfacial forces, e.g. conjoining/disjoining pressure, electrostatics, and capillary condensation, are ubiquitous and can surpass and even dominate bulk inertial or viscous effects on a continuum level. Moreover, the statics and dynamics of three-phase contact lines exhibit a wide range of complex behavior, such as contact angle hysteresis due to surface roughness, surface reaction, or compositional heterogeneities. These thermodynamically and kinetically driven interactions are essential to the development of new materials and processes. A detailed understanding was developed for the factors controlling wettability in multicomponent systems from computational modeling tools, and experimental diagnostics for systems, and processes dominated by interfacial effects. Wettability probed by dynamic advancing and receding contact angle measurements, ellipsometry, and direct determination of the capillary and disjoining forces. Molecular scale experiments determined the relationships between the fundamental interactions between molecular species and with the substrate. Atomistic simulations studied the equilibrium concentration profiles near the solid and vapor interfaces and tested the basic assumptions used in the continuum approaches. These simulations provide guidance in developing constitutive equations, which more accurately take into account the effects of surface induced phase separation and concentration gradients near the three-phase contact line. The development of these accurate models for dynamic multicomponent wetting allows improvement in science based engineering of manufacturing processes previously developed through costly trial and error by varying material formulation and geometry modification.

  8. Isolation, identification and characterization of regional indigenous Saccharomyces cerevisiae strains

    Science.gov (United States)

    Šuranská, Hana; Vránová, Dana; Omelková, Jiřina

    2016-01-01

    In the present work we isolated and identified various indigenous Saccharomyces cerevisiae strains and screened them for the selected oenological properties. These S. cerevisiae strains were isolated from berries and spontaneously fermented musts. The grape berries (Sauvignon blanc and Pinot noir) were grown under the integrated and organic mode of farming in the South Moravia (Czech Republic) wine region. Modern genotyping techniques such as PCR-fingerprinting and interdelta PCR typing were employed to differentiate among indigenous S. cerevisiae strains. This combination of the methods provides a rapid and relatively simple approach for identification of yeast of S. cerevisiae at strain level. In total, 120 isolates were identified and grouped by molecular approaches and 45 of the representative strains were tested for selected important oenological properties including ethanol, sulfur dioxide and osmotic stress tolerance, intensity of flocculation and desirable enzymatic activities. Their ability to produce and utilize acetic/malic acid was examined as well; in addition, H2S production as an undesirable property was screened. The oenological characteristics of indigenous isolates were compared to a commercially available S. cerevisiae BS6 strain, which is commonly used as the starter culture. Finally, some indigenous strains coming from organically treated grape berries were chosen for their promising oenological properties and these strains will be used as the starter culture, because application of a selected indigenous S. cerevisiae strain can enhance the regional character of the wines. PMID:26887243

  9. Isolation, identification and characterization of regional indigenous Saccharomyces cerevisiae strains.

    Science.gov (United States)

    Šuranská, Hana; Vránová, Dana; Omelková, Jiřina

    2016-01-01

    In the present work we isolated and identified various indigenous Saccharomyces cerevisiae strains and screened them for the selected oenological properties. These S. cerevisiae strains were isolated from berries and spontaneously fermented musts. The grape berries (Sauvignon blanc and Pinot noir) were grown under the integrated and organic mode of farming in the South Moravia (Czech Republic) wine region. Modern genotyping techniques such as PCR-fingerprinting and interdelta PCR typing were employed to differentiate among indigenous S. cerevisiae strains. This combination of the methods provides a rapid and relatively simple approach for identification of yeast of S. cerevisiae at strain level. In total, 120 isolates were identified and grouped by molecular approaches and 45 of the representative strains were tested for selected important oenological properties including ethanol, sulfur dioxide and osmotic stress tolerance, intensity of flocculation and desirable enzymatic activities. Their ability to produce and utilize acetic/malic acid was examined as well; in addition, H2S production as an undesirable property was screened. The oenological characteristics of indigenous isolates were compared to a commercially available S. cerevisiae BS6 strain, which is commonly used as the starter culture. Finally, some indigenous strains coming from organically treated grape berries were chosen for their promising oenological properties and these strains will be used as the starter culture, because application of a selected indigenous S. cerevisiae strain can enhance the regional character of the wines. PMID:26887243

  10. Isolation, identification and characterization of regional indigenous Saccharomyces cerevisiae strains

    Directory of Open Access Journals (Sweden)

    Hana Šuranská

    2016-03-01

    Full Text Available Abstract In the present work we isolated and identified various indigenous Saccharomyces cerevisiae strains and screened them for the selected oenological properties. These S. cerevisiae strains were isolated from berries and spontaneously fermented musts. The grape berries (Sauvignon blanc and Pinot noir were grown under the integrated and organic mode of farming in the South Moravia (Czech Republic wine region. Modern genotyping techniques such as PCR-fingerprinting and interdelta PCR typing were employed to differentiate among indigenous S. cerevisiae strains. This combination of the methods provides a rapid and relatively simple approach for identification of yeast of S. cerevisiae at strain level. In total, 120 isolates were identified and grouped by molecular approaches and 45 of the representative strains were tested for selected important oenological properties including ethanol, sulfur dioxide and osmotic stress tolerance, intensity of flocculation and desirable enzymatic activities. Their ability to produce and utilize acetic/malic acid was examined as well; in addition, H2S production as an undesirable property was screened. The oenological characteristics of indigenous isolates were compared to a commercially available S. cerevisiae BS6 strain, which is commonly used as the starter culture. Finally, some indigenous strains coming from organically treated grape berries were chosen for their promising oenological properties and these strains will be used as the starter culture, because application of a selected indigenous S. cerevisiae strain can enhance the regional character of the wines.

  11. Saccharomyces cerevisiae Forms d-2-Hydroxyglutarate and Couples Its Degradation to d-Lactate Formation via a Cytosolic Transhydrogenase.

    Science.gov (United States)

    Becker-Kettern, Julia; Paczia, Nicole; Conrotte, Jean-François; Kay, Daniel P; Guignard, Cédric; Jung, Paul P; Linster, Carole L

    2016-03-18

    The d or l form of 2-hydroxyglutarate (2HG) accumulates in certain rare neurometabolic disorders, and high d-2-hydroxyglutarate (d-2HG) levels are also found in several types of cancer. Although 2HG has been detected in Saccharomyces cerevisiae, its metabolism in yeast has remained largely unexplored. Here, we show that S. cerevisiae actively forms the d enantiomer of 2HG. Accordingly, the S. cerevisiae genome encodes two homologs of the human d-2HG dehydrogenase: Dld2, which, as its human homolog, is a mitochondrial protein, and the cytosolic protein Dld3. Intriguingly, we found that a dld3Δ knock-out strain accumulates millimolar levels of d-2HG, whereas a dld2Δ knock-out strain displayed only very moderate increases in d-2HG. Recombinant Dld2 and Dld3, both currently annotated as d-lactate dehydrogenases, efficiently oxidized d-2HG to α-ketoglutarate. Depletion of d-lactate levels in the dld3Δ, but not in the dld2Δ mutant, led to the discovery of a new type of enzymatic activity, carried by Dld3, to convert d-2HG to α-ketoglutarate, namely an FAD-dependent transhydrogenase activity using pyruvate as a hydrogen acceptor. We also provide evidence that Ser3 and Ser33, which are primarily known for oxidizing 3-phosphoglycerate in the main serine biosynthesis pathway, in addition reduce α-ketoglutarate to d-2HG using NADH and represent major intracellular sources of d-2HG in yeast. Based on our observations, we propose that d-2HG is mainly formed and degraded in the cytosol of S. cerevisiae cells in a process that couples d-2HG metabolism to the shuttling of reducing equivalents from cytosolic NADH to the mitochondrial respiratory chain via the d-lactate dehydrogenase Dld1. PMID:26774271

  12. Atmospheric corrosion of copper under wet/dry cyclic conditions

    International Nuclear Information System (INIS)

    The polarization resistance of copper subjected to NaCl and an ammonium sulfate solution under wet/dry cycling conditions was monitored using an EIS impedance technique. The copper samples were exposed to 1 h of immersion using different solutions of pH, temperature and surface orientation and 7 h of drying. The copper plates corroded more substantially on the skyward side than those for a ground ward side. The degree of protection copper oxide provides decrease in an acidic medium (pH 4) more than in a neutral medium (pH 7). The corrosion rate of copper increases rapidly during the initial stages of exposure then decreases slowly and eventually attains the steady state during the last stages of exposure. The corrosion products were analyzed using X-ray diffraction. The corrosion mechanism for copper studied under wet/dry cyclic conditions was found to proceed under the dissolution-precipitation mechanism

  13. In vitro screening of probiotic properties of Saccharomyces cerevisiae var. boulardii and food-borne Saccharomyces cerevisiae strains

    DEFF Research Database (Denmark)

    van der Aa Kuhle, Alis; Skovgaard, Kerstin; Jespersen, Lene

    2005-01-01

    nontumorigenic porcine jejunal epithelial cell line (IPEC-J2) was investigated by incorporation of H-3-methionine into the yeast cells and use of liquid scintillation counting. Only few of the food-borne S. cerevisiae strains exhibited noteworthy adhesiveness with the strongest levels of adhesion (13...... effects hence indicating that food-borne strains of S. cerevisiae may possess probiotic properties in spite of low adhesiveness. © 2004 Elsevier B.V. All rights reserved....

  14. Rapid Nitrogen Cycling Following Wet-Up Results from Heterotroph, then Nitrifier Response

    Science.gov (United States)

    Placella, S.; Herman, D.; Firestone, M.

    2009-12-01

    The first rainfall following the hot, dry summer in arid and semi-arid ecosystems, known as wet-up, results in large pulses of carbon dioxide and nitrous oxide, two radiatively important gases. Nitrous oxide in general, is produced by nitrifiers and denitrifiers. Using laboratory simulations of wet-up, we monitored soil pools of ammonium and nitrate, gross rates of nitrogen mineralization and nitrification, effluxes of carbon dioxide and nitrous oxide, and gene expression of archaeal and bacterial amoA, a functional gene for nitrification and nirK, a functional gene for denitrification. Results from a California annual grassland soil show significant increases in the ammonium pool within one hour of water addition followed by a significant increase in the nitrate pool within three hours of water addition. Gross nitrogen mineralization and gross nitrification were very high with nitrogen mineralization being highest within three hours of wet-up. Ammonia-oxidizers were most active at nine hours after water addition. Nitrous oxide emissions followed the same pattern as nitrifiers, suggesting nitrification may play an important role in nitrous oxide emissions during wet-up.

  15. Drop splashing is independent of substrate wetting

    CERN Document Server

    Latka, Andrzej; Nagel, Sidney R; de Pablo, Juan J

    2016-01-01

    A liquid drop impacting a dry solid surface with sufficient kinetic energy will splash, breaking apart into numerous secondary droplets. This phenomenon shows many similarities to forced wetting, including the entrainment of air at the contact line. Because of these similarities and the fact that forced wetting has been shown to depend on the wetting properties of the surface, existing theories predict splashing to depend on wetting properties as well. However, using high-speed interference imaging we observe that wetting properties have no effect on splashing for various liquid-surface combinations. Additionally, by fully resolving the Navier-Stokes equations at length and time scales inaccessible to experiments, we find that the shape and motion of the air-liquid interface at the contact line are independent of wettability. We use these findings to evaluate existing theories and to compare splashing with forced wetting.

  16. Wetting of star-shaped macromolecules

    Science.gov (United States)

    Glynos, Emmanouil; Frieberg, Bradley; Sakellariou, Georgios; Green, Peter

    2013-03-01

    We show that the equilibrium contact angles and line tensions of macroscopic droplets of star-shaped polystyrene (PS) macromolecules of functionality, f, and degree of polymerization per arm, Narm, on oxidized silicon substrates, may be as much as one and two orders of magnitude, respectively, smaller than their linear analogs, depending on f and Narm. The dewetting characteristics of the linear and star polymers also differ. Thin film of LPS and SPS dewet SiOx substrates due to destabilizing long-range intermolecular forces. However, while macroscopic droplets surrounded by droplets of nanoscale dimensions characterize the late-stage dewetting morphology of the LPS system, the macroscopic droplets of the SPS molecules reside on a stable layer of molecules adsorbed to the substrate. The thickness of the adsorbed layer depends on both f and Narm. We provide evidence that the wetting/dewetting characteristics of the SPS macromolecules are largely determined by the competition between interfacially attractive conformational entropic effects and steric repulsion effects, for molecules of sufficiently large f and small Narm. National Science Foundation (NSF), Division of Material Research, Polymer Program No. 0906425

  17. Failure mechanisms and assembly-process-based solution of FCBGA high lead C4 bump non-wetting

    International Nuclear Information System (INIS)

    This paper studies the typical failure modes and failure mechanisms of non-wetting in an FCBGA (flip chip ball grid array) assembly. We have identified that the residual lead and tin oxide layer on the surface of the die bumps as the primary contributor to non-wetting between die bumps and substrate bumps during the chip-attach reflow process. Experiments with bump reflow parameters revealed that an optimized reflow dwell time and H2 flow rate in the reflow oven can significantly reduce the amount of lead and tin oxides on the surface of the die bumps, thereby reducing the non-wetting failure rate by about 90%. Both failure analysis results and mass production data validate the non-wetting failure mechanisms identified by this study. As a result of the reflow process optimization, the failure rate associated with non-wetting is significantly reduced, which further saves manufacturing cost and increases capacity utilization. (semiconductor technology)

  18. Wetting an oxide heterostructure: influence of surface water adsorbates on the electronic properties of LaAlO3/SrTiO3 studied by in situ photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Oxide heterostructures display many interesting phenomena, one example being the formation of a two-dimensional electron system (2DES) at the LaAlO3/SrTiO3 (LAO/STO) interface beyond a critical thickness of 4 monolayers (ML) of the polar LAO. An explanation for this behavior is the so-called electronic reconstruction. In this context it was recently shown that polar adsorbates can enhance the conductivity of the 2DES. Besides their electrostatic influence it was discussed that surface defects/adsorbates can also act as a charge reservoir. To examine the impact of surface adsorbates on the 2DES we performed in situ photoelectron spectroscopy on 6ML thick LAO/STO heterostructures exposed to a defined amount of water vapor. In response to the adsorbed water we observe an increase of charge carriers at titanium sites. Furthermore a comparison between bulk and interface sensitive measurements indicates that the additional charge carriers are located at the interface.

  19. Wetting on Lines and Lattices of Cylinders

    OpenAIRE

    Osborn, W. R.; Yeomans, J. M.

    1994-01-01

    This paper discusses wetting and capillary condensation transitions on a line and a rectangular array of cylinders using an interface potential formalism. For a line of cylinders, there is a capillary condensation transition followed by complete wetting if the cylinders are sufficiently close together. Both transitions disappear as the cylinder separation is increased. The dependence of the wetting phase diagram of a rectangular array of cylinders is discussed as a function of the chemical po...

  20. Carbon nanotube fiber spun from wetted ribbon

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yuntian T; Arendt, Paul; Zhang, Xiefei; Li, Qingwen; Fu, Lei; Zheng, Lianxi

    2014-04-29

    A fiber of carbon nanotubes was prepared by a wet-spinning method involving drawing carbon nanotubes away from a substantially aligned, supported array of carbon nanotubes to form a ribbon, wetting the ribbon with a liquid, and spinning a fiber from the wetted ribbon. The liquid can be a polymer solution and after forming the fiber, the polymer can be cured. The resulting fiber has a higher tensile strength and higher conductivity compared to dry-spun fibers and to wet-spun fibers prepared by other methods.

  1. A mesoscopic model for (de)wetting.

    Science.gov (United States)

    Merabia, S; Pagonabarraga, I

    2006-06-01

    We present a mesoscopic model for simulating the dynamics of a non-volatile liquid on a solid substrate. The wetting properties of the solid can be tuned from complete wetting to total non-wetting. This model opens the way to study the dynamics of drops and liquid thin films at mesoscopic length scales of the order of the nanometer. As particular applications, we analyze the kinetics of spreading of a liquid drop wetting a solid substrate and the dewetting of a liquid film on a hydrophobic substrate. In all these cases, very good agreement is found between simulations and theoretical predictions. PMID:16775662

  2. Characteristics of wet work in nurses

    NARCIS (Netherlands)

    Jungbauer, FHW; Steenstra, FB; Groothoff, JW; Coenraads, PJ

    2005-01-01

    Background objectives: Nursing is known for its high prevalence of hand dermatitis, mainly caused by the intense exposure to wet work in nursing activities. We aimed to study the characteristics of wet work exposure in nursing. Method: Trained observers monitored the duration and frequency of differ

  3. Anomalous wetting of helium on cesium

    International Nuclear Information System (INIS)

    The authors report studies of the anomalous wetting of a cesium substrate by a liquid helium film by means of the technique of third sound. A hysteretic pre-wetting transition is observed as a function of the amount of helium in the experimental cell. 10 refs., 2 figs

  4. Condition of research reactor spent nuclear fuel in wet storage

    International Nuclear Information System (INIS)

    The condition of spent nuclear fuel (SNF) in wet storage at ten Soviet-designed research reactors has been assessed in the light of international experience in order to identify any associated safety issues. These reactors use Al-clad UO2-Al or U-Al alloy dispersion fuels of ≥20% enrichment that were fabricated in Russia; the reactors have been in operation since 1955-70. Although originally sent for reprocessing, much of the SNF generated over the last 25-30 years has been stored in fuel storage pools (FSPs) of variable water quality. The external condition of wet-stored SNF assemblies from the reactors surveyed varied from significant failure due to galvanic corrosion that was driven by poor water quality, through gradual pitting caused by slightly impure water, to a stable condition of no observable change in the oxidized Al alloy surface of the irradiated fuel. SNF stability in wet storage seems to depend on three factors: Al being the sole metal in the FSP (to avoid galvanic action); good water chemistry to suppress attack of the oxide layer by aggressive ions like Cl-, and gentle handling to limit physical damage to the oxide layer. If one of these factors is not satisfied, SNF degradation will take place; if more than one factor is not satisfied, failure of the Al cladding may occur. In general, however, even SNF failure in wet storage does not appear to raise significant safety concerns. A possible exception is where galvanic corrosion combined with poor water quality has caused massive fuel failure, as at the RA reactor in Belgrade. A potential safety problem was identified at reactors where unalloyed Al liners had been used in the FSPs. Unlike SNF that develops a protective oxide layer in-reactor, these Al liners were unprotected and prone to significant corrosion during an ill-defined early period of poor water quality. The risk of losing water from FSPs due to liner failure should be evaluated for all research reactors. Where the risk of FSP failure

  5. Condition of research reactor spent nuclear fuels in wet storage

    International Nuclear Information System (INIS)

    Full text: The condition of spent nuclear fuel (SNF) in wet storage at ten Soviet-designed research reactors has been assessed in the light of international experience in order to identify any associated safety issues. These reactors use Al-clad UO2-Al or U-Al alloy dispersion fuels of ≥20% enrichment that were fabricated in Russia; the reactors have been in operation since 1955-70. Although originally sent for reprocessing, much of the SNF generated over the last 25-30 years has been stored in fuel storage pools (FSPs) of variable water quality. The external condition of wet-stored SNF assemblies from the reactors surveyed varied from significant failure due to galvanic corrosion that was driven by poor water quality, through gradual pitting caused by slightly impure water, to a stable condition of no observable change in the oxidized Al alloy surface of the irradiated fuel. SNF stability in wet storage seems to depend on three factors: Al being the sole metal in the FSP (to avoid galvanic action); good water chemistry to suppress attack of the oxide layer by aggressive ions like Cl-, and gentle handling to limit physical damage to the oxide layer. If one of these factors is not satisfied, SNF degradation will take place; if more than one factor is not satisfied, failure of the Al cladding may occur. In general, however, even SNF failure in wet storage does not appear to raise significant safety concerns. A possible exception is where galvanic corrosion combined with poor water quality has caused massive fuel failure, as at the RA reactor in Belgrade. A potential safety problem was identified at reactors where unalloyed Al liners had been used in the FSPs. Unlike SNF that develops a protective oxide layer in-reactor, these Al liners were unprotected and prone to significant corrosion during an ill-defined early period of poor water quality. The risk of losing water from FSPs due to liner failure should be evaluated for all research reactors. Where the risk of

  6. WetA is required for conidiogenesis and conidium maturation in the ascomycete fungus Fusarium graminearum.

    Science.gov (United States)

    Son, Hokyoung; Kim, Myung-Gu; Min, Kyunghun; Lim, Jae Yun; Choi, Gyung Ja; Kim, Jin-Cheol; Chae, Suhn-Kee; Lee, Yin-Won

    2014-01-01

    Fusarium graminearum, a prominent fungal pathogen that infects major cereal crops, primarily utilizes asexual spores to spread disease. To understand the molecular mechanisms underlying conidiogenesis in F. graminearum, we functionally characterized the F. graminearum ortholog of Aspergillus nidulans wetA, which has been shown to be involved in conidiogenesis and conidium maturation. Deletion of F. graminearum wetA did not alter mycelial growth, sexual development, or virulence, but the wetA deletion mutants produced longer conidia with fewer septa, and the conidia were sensitive to acute stresses, such as oxidative stress and heat stress. Furthermore, the survival rate of aged conidia from the F. graminearum wetA deletion mutants was reduced. The wetA deletion resulted in vigorous generation of single-celled conidia through autophagy-dependent microcycle conidiation, indicating that WetA functions to maintain conidial dormancy by suppressing microcycle conidiation in F. graminearum. Transcriptome analyses demonstrated that most of the putative conidiation-related genes are expressed constitutively and that only a few genes are specifically involved in F. graminearum conidiogenesis. The conserved and distinct roles identified for WetA in F. graminearum provide new insights into the genetics of conidiation in filamentous fungi. PMID:24186953

  7. Display of phytase on the cell surface of Saccharomyces cerevisiae to degrade phytate phosphorus and improve bioethanol production.

    Science.gov (United States)

    Chen, Xianzhong; Xiao, Yan; Shen, Wei; Govender, Algasan; Zhang, Liang; Fan, You; Wang, Zhengxiang

    2016-03-01

    Currently, development of biofuels as an alternative fuel has gained much attention due to resource and environmental challenges. Bioethanol is one of most important and dominant biofuels, and production using corn or cassava as raw materials has become a prominent technology. However, phytate contained in the raw material not only decreases the efficiency of ethanol production, but also leads to an increase in the discharge of phosphorus, thus impacting on the environment. In this study, to decrease phytate and its phosphorus content in an ethanol fermentation process, Saccharomyces cerevisiae was engineered through a surface-displaying system utilizing the C-terminal half of the yeast α-agglutinin protein. The recombinant yeast strain, PHY, was constructed by successfully displaying phytase on the surface of cells, and enzyme activity reached 6.4 U/g wet biomass weight. Ethanol productions using various strains were compared, and the results demonstrated that the specific growth rate and average fermentation rate of the PHY strain were higher 20 and 18 %, respectively, compared to the control strain S. cerevisiae CICIMY0086, in a 5-L bioreactor process by simultaneous saccharification and fermentation. More importantly, the phytate phosphorus concentration decreased by 89.8 % and free phosphorus concentration increased by 142.9 % in dry vinasse compared to the control in a 5-L bioreactor. In summary, we constructed a recombinant S. cerevisiae strain displaying phytase on the cell surface, which could improve ethanol production performance and effectively reduce the discharge of phosphorus. The strain reported here represents a useful novel engineering platform for developing an environment-friendly system for bioethanol production from a corn substrate. PMID:26610799

  8. Construction of novel Saccharomyces cerevisiae strains for bioethanol active dry yeast (ADY production.

    Directory of Open Access Journals (Sweden)

    Daoqiong Zheng

    Full Text Available The application of active dry yeast (ADY in bioethanol production simplifies operation processes and reduces the risk of bacterial contamination. In the present study, we constructed a novel ADY strain with improved stress tolerance and ethanol fermentation performances under stressful conditions. The industrial Saccharomyces cerevisiae strain ZTW1 showed excellent properties and thus subjected to a modified whole-genome shuffling (WGS process to improve its ethanol titer, proliferation capability, and multiple stress tolerance for ADY production. The best-performing mutant, Z3-86, was obtained after three rounds of WGS, producing 4.4% more ethanol and retaining 2.15-fold higher viability than ZTW1 after drying. Proteomics and physiological analyses indicated that the altered expression patterns of genes involved in protein metabolism, plasma membrane composition, trehalose metabolism, and oxidative responses contribute to the trait improvement of Z3-86. This work not only successfully developed a novel S. cerevisiae mutant for application in commercial bioethanol production, but also enriched the current understanding of how WGS improves the complex traits of microbes.

  9. A Regulatory Role of NAD Redox Status on Flavin Cofactor Homeostasis in S. cerevisiae Mitochondria

    Directory of Open Access Journals (Sweden)

    Teresa Anna Giancaspero

    2013-01-01

    Full Text Available Flavin adenine dinucleotide (FAD and nicotinamide adenine dinucleotide (NAD are two redox cofactors of pivotal importance for mitochondrial functionality and cellular redox balance. Despite their relevance, the mechanism by which intramitochondrial NAD(H and FAD levels are maintained remains quite unclear in Saccharomyces cerevisiae. We investigated here the ability of isolated mitochondria to degrade externally added FAD and NAD (in both its reduced and oxidized forms. A set of kinetic experiments demonstrated that mitochondrial FAD and NAD(H destroying enzymes are different from each other and from the already characterized NUDIX hydrolases. We studied here, in some detail, FAD pyrophosphatase (EC 3.6.1.18, which is inhibited by NAD+ and NADH according to a noncompetitive inhibition, with Ki values that differ from each other by an order of magnitude. These findings, together with the ability of mitochondrial FAD pyrophosphatase to metabolize endogenous FAD, presumably deriving from mitochondrial holoflavoproteins destined to degradation, allow for proposing a novel possible role of mitochondrial NAD redox status in regulating FAD homeostasis and/or flavoprotein degradation in S. cerevisiae.

  10. Physiological and transcriptional characterization of Saccharomyces cerevisiae engineered for production of fatty acid ethyl esters.

    Science.gov (United States)

    de Jong, Bouke Wim; Siewers, Verena; Nielsen, Jens

    2016-02-01

    Saccharomyces cerevisiae has previously been engineered to become a cell factory for the production of fatty acid ethyl esters (FAEEs), molecules suitable for crude diesel replacement. To find new metabolic engineering targets for the improvement of FAEE cell factories, three different FAEE-producing strains of S. cerevisiae, constructed previously, were compared and characterized by quantification of key fluxes and genome-wide transcription analysis. From both the physiological and the transcriptional data, it was indicated that strain CB2I20, with high expression of a heterologous wax ester synthase gene (ws2) and strain BdJ15, containing disruptions of genes DGA1, LRO1, ARE1, ARE2 and POX1, which prevent the conversion of acyl-CoA to sterol esters, triacylglycerides and the degradation to acetyl-CoA, triggered oxidative stress that consequently influenced cellular growth. In the latter strain, stress was possibly triggered by disabling the buffering capacity of lipid droplets in encapsulating toxic fatty acids such as oleic acid. Additionally, it was indicated that there was an increased demand for NADPH required for the reduction steps in fatty acid biosynthesis. In conclusion, our analysis clearly shows that engineering of fatty acid biosynthesis results in transcriptional reprogramming and has a significant effect on overall cellular metabolism. PMID:26590613

  11. Vacuolar compartmentation of the cadmium-glutathione complex protects Saccharomyces cerevisiae from mutagenesis.

    Science.gov (United States)

    Adamis, Paula D B; Panek, Anita D; Eleutherio, Elis C A

    2007-08-30

    In the yeast Saccharomyces cerevisiae, gamma-glutamyl transferase (gamma-GT; EC 2.3.2.2) is a vacuolar-membrane bound enzyme. In this work we verified that S. cerevisiae cells deficient in gamma-GT absorbed almost 2.5-fold as much cadmium as the wild-type (wt) cells, suggesting that this enzyme might be responsible for the recycle of cadmium-glutathione complex stored in the vacuole. The mutant strain showed difficulty in keeping constant levels of glutathione (GSH) during the stress, although the GSH-reductase activity was practically the same in both wt and mutant strains, before and after metal stress. This difficulty to maintain the GSH levels in the gamma-GT mutant strain led to high levels of lipid peroxidation and carbonyl proteins in response to cadmium, higher than in the wt, but lower than in a mutant deficient in GSH synthesis. Although the increased levels of oxidative stress, gamma-GT mutant strain showed to be tolerant to cadmium and showed similar mutation rates to the wt, indicating that the compartmentation of the GSH-cadmium complex in vacuole protects cells against the mutagenic action of the metal. Confirming this hypothesis, a mutant strain deficient in Ycf1, which present high concentrations of GSH-cadmium in cytoplasm due to its deficiency in transport the complex to vacuole, showed increased mutation rates. PMID:17644279

  12. Horizontally acquired oligopeptide transporters favour adaptation of Saccharomyces cerevisiae wine yeast to oenological environment.

    Science.gov (United States)

    Marsit, Souhir; Sanchez, Isabelle; Galeote, Virginie; Dequin, Sylvie

    2016-04-01

    In the past decade, horizontal gene transfer (HGT) has emerged as a major evolutionary process that has shaped the genome of Saccharomyces cerevisiae wine yeasts. We recently showed that a large Torulaspora microellipsoides genomic island carrying two oligopeptide transporters encoded by FOT genes increases the fitness of wine yeast during fermentation of grape must. However, the impact of these genes on the metabolic network of S. cerevisiae remained uncharacterized. Here we show that Fot-mediated peptide uptake substantially affects the glutamate node and the NADPH/NADP(+) balance, resulting in the delayed uptake of free amino acids and altered profiles of metabolites and volatile compounds. Transcriptome analysis revealed that cells using a higher amount of oligopeptides from grape must are less stressed and display substantial variation in the expression of genes in the central pathways of carbon and nitrogen metabolism, amino acid and protein biosynthesis, and the oxidative stress response. These regulations shed light on the molecular and metabolic mechanisms involved in the higher performance and fitness conferred by the HGT-acquired FOT genes, pinpointing metabolic effects that can positively affect the organoleptic balance of wines. PMID:26549518

  13. Photodynamic DNA damage induced by phycocyanin and its repair in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    M. Pádula

    1999-09-01

    Full Text Available In the present study, we analyzed DNA damage induced by phycocyanin (PHY in the presence of visible light (VL using a set of repair endonucleases purified from Escherichia coli. We demonstrated that the profile of DNA damage induced by PHY is clearly different from that induced by molecules that exert deleterious effects on DNA involving solely singlet oxygen as reactive species. Most of PHY-induced lesions are single strand breaks and, to a lesser extent, base oxidized sites, which are recognized by Nth, Nfo and Fpg enzymes. High pressure liquid chromatography coupled to electrochemical detection revealed that PHY photosensitization did not induce 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo at detectable levels. DNA repair after PHY photosensitization was also investigated. Plasmid DNA damaged by PHY photosensitization was used to transform a series of Saccharomyces cerevisiae DNA repair mutants. The results revealed that plasmid survival was greatly reduced in rad14 mutants, while the ogg1 mutation did not modify the plasmid survival when compared to that in the wild type. Furthermore, plasmid survival in the ogg1 rad14 double mutant was not different from that in the rad14 single mutant. The results reported here indicate that lethal lesions induced by PHY plus VL are repaired differently by prokaryotic and eukaryotic cells. Morever, nucleotide excision repair seems to play a major role in the recognition and repair of these lesions in Saccharomyces cerevisiae.

  14. Removing cadmium from electroplating wastewater by waste saccharomyces cerevisiae

    Institute of Scientific and Technical Information of China (English)

    DAI Shu-juan; WEI De-zhou; ZHOU Dong-qin; JIA Chun-yun; WANG Yu-juan; LIU Wen-gang

    2008-01-01

    The appropriate condition and scheme of removing cadmium from electroplating wastewater were investigated by adsorption-precipitation method using waste saccharomyces cerevisiae(WSC) as sorbent. Effect factors on biosorption of cadmium in cadmium-containing electroplating wastewater by waste saccharomyces cerevisiae and precipitation process of waste saccharomyces cerevisiae after adsorbing cadmium were studied. The results show that removal rate of cadmium is over 88% after 30 min adsorbing under the condition of cadmium concentration 26 mg/L, the dosage of waste saccharomyces cerevisiae 16.25 g/L, temperature 18 ℃, pH 6.0 and precipitation time 4 h. Biosorption-precipitation method is effective to remove cadmium in cadmium-containing electroplating wastewater by waste saccharomyces cerevisiae. The SEM, infrared spectroscopy and Zeta-potential of the cells show that chemical chelating is the main adsorption form; electrostatic attraction, hydrogen bonding and van der Waals force all function in adsorption process; and ―NH2―,―C=O―,―C=O―NH―,―CH3, ―OH are the main adsorption groups.

  15. Inhibition effect of expression of Cu/Zn superoxide dismutase from rice on synthesis of Glutathione in Saccharomyces cerevisiae

    Institute of Scientific and Technical Information of China (English)

    AI Yu-zhuo; DU Ye-jie; ZU Yuan-gang; AN Zhi-gang

    2008-01-01

    The expression of a rice Cu/Zn superoxide dismutase (Cu/Zn-SOD) in Saccharomyces cerevisiae regulated by GAPDH promoter, involved in the inhibition of endogenous Glutathione (GSH) synthesis, and the competitive expression was detected by constructing the expression vector transferred Cu/Zn-SOD gene into wild-type S. Cerevisiae. Transcription and expression of the Cu/Zn-SOD gene in S. Cerevisiawere were confirmed by northern blot and SDS-PAGE, respectively, and activity of the Cu/Zn-SOD from crude extracts was enzymatically detected based on the effect of nitroblue tetrazolium (NBT) after running a native polyacrylamide gel. The GSH synthesis was also tested by DTNB (5, 5′-Dithiobis (2-nitrobenzoic acid)) method. Results showed that GSH synthesis was evidently suppressed by the expression of Cu/Zn-SOD gene in both control and heat shock strains. It implied that the expression of the Cu/Zn-SOD gene in S. Cerevisiae has more potential facility in response to oxidative exposure than that of endogenous GSH, although Cu/Zn-SOD and GSH were both contributed to the function of oxygen radical oxidoreduction.

  16. Divergence in wine characteristics produced by wild and domesticated strains of Saccharomyces cerevisiae

    OpenAIRE

    Katie E Hyma; Saerens, Sofie M; Verstrepen, Kevin J.; Justin C Fay

    2011-01-01

    The budding yeast Saccharomyces cerevisiae is the primary species used by wine makers to convert sugar into alcohol during wine fermentation. Saccharomyces cerevisiae is found in vineyards, but is also found in association with oak trees and other natural sources. Although wild strains of S. cerevisiae as well as other Saccharomyces species are also capable of wine fermentation, a genetically distinct group of S. cerevisiae strains is primarily used to produce wine, consistent with the idea t...

  17. Crystal structure of Saccharomyces cerevisiae 6-phosphogluconate dehydrogenase Gnd1

    Directory of Open Access Journals (Sweden)

    Zhou Cong-Zhao

    2007-06-01

    Full Text Available Abstract Background As the third enzyme of the pentose phosphate pathway, 6-phosphogluconate dehydrogenase (6PGDH is the main generator of cellular NADPH. Both thioredoxin reductase and glutathione reductase require NADPH as the electron donor to reduce oxidized thioredoxin or glutathione (GSSG. Since thioredoxin and GSH are important antioxidants, it is not surprising that 6PGDH plays a critical role in protecting cells from oxidative stress. Furthermore the activity of 6PGDH is associated with several human disorders including cancer and Alzheimer's disease. The 3D structural investigation would be very valuable in designing small molecules that target this enzyme for potential therapeutic applications. Results The crystal structure of 6-phosphogluconate dehydrogenase (6PGDH/Gnd1 from Saccharomyces cerevisiae has been determined at 2.37 Å resolution by molecular replacement. The overall structure of Gnd1 is a homodimer with three domains for each monomer, a Rossmann fold NADP+ binding domain, an all-α helical domain contributing the majority to hydrophobic interaction between the two subunits and a small C-terminal domain penetrating the other subunit. In addition, two citrate molecules occupied the 6PG binding pocket of each monomer. The intact Gnd1 had a Km of 50 ± 9 μM for 6-phosphogluconate and of 35 ± 6 μM for NADP+ at pH 7.5. But the truncated mutants without the C-terminal 35, 39 or 53 residues of Gnd1 completely lost their 6PGDH activity, despite remaining the homodimer in solution. Conclusion The overall tertiary structure of Gnd1 is similar to those of 6PGDH from other species. The substrate and coenzyme binding sites are well conserved, either from the primary sequence alignment, or from the 3D structural superposition. Enzymatic activity assays suggest a sequential mechanism of catalysis, which is in agreement with previous studies. The C-terminal domain of Gnd1 functions as a hook to further tighten the dimer, but it is not

  18. Precursor films in wetting phenomena

    International Nuclear Information System (INIS)

    The spontaneous spreading of non-volatile liquid droplets on solid substrates poses a classic problem in the context of wetting phenomena. It is well known that the spreading of a macroscopic droplet is in many cases accompanied by a thin film of macroscopic lateral extent, the so-called precursor film, which emanates from the three-phase contact line region and spreads ahead of the latter with a much higher speed. Such films have been usually associated with liquid-on-solid systems, but in the last decade similar films have been reported to occur in solid-on-solid systems. While the situations in which the thickness of such films is of mesoscopic size are fairly well understood, an intriguing and yet to be fully understood aspect is the spreading of microscopic, i.e. molecularly thin, films. Here we review the available experimental observations of such films in various liquid-on-solid and solid-on-solid systems, as well as the corresponding theoretical models and studies aimed at understanding their formation and spreading dynamics. Recent developments and perspectives for future research are discussed. (topical review)

  19. Precursor films in wetting phenomena.

    Science.gov (United States)

    Popescu, M N; Oshanin, G; Dietrich, S; Cazabat, A-M

    2012-06-20

    The spontaneous spreading of non-volatile liquid droplets on solid substrates poses a classic problem in the context of wetting phenomena. It is well known that the spreading of a macroscopic droplet is in many cases accompanied by a thin film of macroscopic lateral extent, the so-called precursor film, which emanates from the three-phase contact line region and spreads ahead of the latter with a much higher speed. Such films have been usually associated with liquid-on-solid systems, but in the last decade similar films have been reported to occur in solid-on-solid systems. While the situations in which the thickness of such films is of mesoscopic size are fairly well understood, an intriguing and yet to be fully understood aspect is the spreading of microscopic, i.e. molecularly thin, films. Here we review the available experimental observations of such films in various liquid-on-solid and solid-on-solid systems, as well as the corresponding theoretical models and studies aimed at understanding their formation and spreading dynamics. Recent developments and perspectives for future research are discussed. PMID:22627067

  20. Calcium phosphate bioceramics prepared from wet chemically precipitated powders

    Directory of Open Access Journals (Sweden)

    Kristine Salma

    2010-03-01

    Full Text Available In this work calcium phosphates were synthesized by modified wet chemical precipitation route. Contrary to the conventional chemical precipitation route calcium hydroxide was homogenized with planetary mill. Milling calcium oxide and water in planetary ball mill as a first step of synthesis provides a highly dispersed calcium hydroxide suspension. The aim of this work was to study the influence of main processing parameters of wet chemical precipitation synthesis product and to control the morphology, phase and functional group composition and, consequently, thermal stability and microstructure of calcium phosphate bioceramics after thermal treatment. The results showed that it is possible to obtain calcium phosphates with different and reproducible phase compositions after thermal processing (hydroxyapatite [HAp], β-tricalcium phosphate [β-TCP] and HAp/β-TCP by modified wet-chemical precipitation route. The β-TCP phase content in sintered bioceramics samples is found to be highly dependent on the changes in technological parameters and it can be controlled with ending pH, synthesis temperature and thermal treatment. Pure, crystalline and highly thermally stable (up to 1300°C HAp bioceramics with homogenous grainy microstructure, grain size up to 200–250 nm and high open porosity can be successfully obtained by powder synthesized at elevated synthesis temperature of 70°C and stabilizing ending pH at 9.

  1. Micromachining on copper and nickel by electrochemical wet stamping

    International Nuclear Information System (INIS)

    The fabrication of microstructures on copper and nickel has been achieved by an approach named electrochemical wet stamping (E-WETS). The E-WETS process allows the direct imprinting of microscopic reliefs on an agarose stamp into nickel and copper through a selective anodic dissolution process. The pre-patterned agarose with a high gel strength that has been soaked in a desired etching solution is employed as a stamp. It can direct and supply the solution preferentially on the contact area owing to the constant supply of electrolyte from the agarose stamp to the interface and then the electrochemical reaction is limited only to the contact area. Simultaneously, the product can be removed from the gel/substrate interface. On the basis of the electrochemical behavior of the copper electrode in contact with the agarose full of 0.1 M HClO4, the potential for the electrochemical micromachining was chosen to be a relatively low value, 0.4 V versus SCE, to prevent the generation of cuprous oxide. A voltage pulse was applied to the electrochemical machining of nickel. The pulse amplitude was set to 8 V versus SCE to take the electrode into the transpassivation region rather than the passivation region in the pulse duration. Furthermore, the different electrochemical mechanisms involved in the etching process have been discussed in detail

  2. Study of wet blasting of components in nuclear power stations

    Energy Technology Data Exchange (ETDEWEB)

    Hall, J

    1999-12-01

    This report looks at the method of wet blasting radioactive components in nuclear power stations. The wet blaster uses pearl shaped glass beads with the dimensions of 150-250 {mu}m mixed with water as blasting media. The improved design, providing outer operator's positions with proper radiation protection and more efficient blasting equipment has resulted in a lesser dose taken by the operators. The main reason to decontaminate components in nuclear power plants is to enable service on these components. On components like valves, pump shafts, pipes etc. oxides form and bind radiation. These components are normally situated at some distance from the reactor core and will mainly suffer from radiation from so called activation products. When a component is to be decontaminated it can be decontaminated to a radioactive level where it will be declassified. This report has found levels ranging from 150-1000 Bq/kg allowing declassification of radioactive materials.This difference is found between different countries and different organisations. The report also looks at the levels of waste generated using wet blasting. This is done by tracking the contamination to determine where it collects. It is either collected in the water treatment plant or collected in the blasting media. At Barsebaeck the waste levels, from de-contaminating nearly 800 components in one year, results in a waste volume of about 0,250 m{sup 3}. This waste consists of low and medium level waste and will cost about 3 600 EURO to store. The conclusions of the report are that wet blasting is an indispensable way to treat contaminated components in modern nuclear power plants. The wet blasting equipment can be improved by using a robot enabling the operators to remotely treat components from the outer operator's positions. There they will benefit from better radiation protection thus further reduce their taken dose. The wet blasting equipment could also be used to better control the levels of

  3. Directed Evolution towards Increased Isoprenoid Production in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Carlsen, Simon; Nielsen, Michael Lynge; Kielland-Brandt, Morten;

    Due to declining drug discovery rates from organic synthetic libraries, pharmaceutical companies are turning their attention towards secondary metabolites. Isoprenoids, also known as terpenoids, constitute the largest known group of secondary metabolites isolated to date, encompassing more than 55...... pyrophosphate and geranylgeranyl pyrophosphate for large-scale microbial production of terpenoids. Saccharomyces cerevisiae was chosen as production platform due to its widespread use in industrial production and the waste number of molecular biology tools which is available for its manipulation. The effort...... for discovering new genetic perturbations, which would results in and increased production of isoprenoids by S. cerevisiae has been very limited. This project is focus on creating diversity within a lycopene producing S. cerevisiae strain by construction of gDNA-, cDNA-, and transposon-libraries. The diversified...

  4. Wetting and infiltration of nitride bonded silicon nitride by liquid silicon

    Science.gov (United States)

    Schneider, V.; Reimann, C.; Friedrich, J.

    2016-04-01

    Nitride bonded silicon nitride (NBSN) is a promising crucible material for the repeated use in the directional solidification of multicrystalline (mc) silicon ingots for photovoltaic applications. Due to wetting and infiltration, however, silicon nitride in its initial state does not offer the desired reusability. In this work the sessile drop method is used to systematically study the wetting and infiltration behavior of NBSN after applying different oxidation procedures. It is found that the wetting of the NBSN crucible by liquid silicon can be prevented by the oxidation of the geometrical surface. The infiltration of liquid silicon into the porous crucible can be suppressed by oxygen enrichment within the volume of the NBSN, i.e. at the pore walls of the crucibles. The realized reusability of the NBSN is demonstrated by reusing a NBSN crucible six times for the directional solidification of undoped multicrystalline silicon ingots.

  5. Order of wetting transitions in electrolyte solutions

    Energy Technology Data Exchange (ETDEWEB)

    Ibagon, Ingrid, E-mail: ingrid@is.mpg.de; Bier, Markus, E-mail: bier@is.mpg.de; Dietrich, S. [Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, 70569 Stuttgart, Germany and IV. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart (Germany)

    2014-05-07

    For wetting films in dilute electrolyte solutions close to charged walls we present analytic expressions for their effective interface potentials. The analysis of these expressions renders the conditions under which corresponding wetting transitions can be first- or second-order. Within mean field theory we consider two models, one with short- and one with long-ranged solvent-solvent and solvent-wall interactions. The analytic results reveal in a transparent way that wetting transitions in electrolyte solutions, which occur far away from their critical point (i.e., the bulk correlation length is less than half of the Debye length) are always first-order if the solvent-solvent and solvent-wall interactions are short-ranged. In contrast, wetting transitions close to the bulk critical point of the solvent (i.e., the bulk correlation length is larger than the Debye length) exhibit the same wetting behavior as the pure, i.e., salt-free, solvent. If the salt-free solvent is governed by long-ranged solvent-solvent as well as long-ranged solvent-wall interactions and exhibits critical wetting, adding salt can cause the occurrence of an ion-induced first-order thin-thick transition which precedes the subsequent continuous wetting as for the salt-free solvent.

  6. Order of wetting transitions in electrolyte solutions

    International Nuclear Information System (INIS)

    For wetting films in dilute electrolyte solutions close to charged walls we present analytic expressions for their effective interface potentials. The analysis of these expressions renders the conditions under which corresponding wetting transitions can be first- or second-order. Within mean field theory we consider two models, one with short- and one with long-ranged solvent-solvent and solvent-wall interactions. The analytic results reveal in a transparent way that wetting transitions in electrolyte solutions, which occur far away from their critical point (i.e., the bulk correlation length is less than half of the Debye length) are always first-order if the solvent-solvent and solvent-wall interactions are short-ranged. In contrast, wetting transitions close to the bulk critical point of the solvent (i.e., the bulk correlation length is larger than the Debye length) exhibit the same wetting behavior as the pure, i.e., salt-free, solvent. If the salt-free solvent is governed by long-ranged solvent-solvent as well as long-ranged solvent-wall interactions and exhibits critical wetting, adding salt can cause the occurrence of an ion-induced first-order thin-thick transition which precedes the subsequent continuous wetting as for the salt-free solvent

  7. Understanding the 3-hydroxypropionic acid tolerance mechanism in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Kildegaard, Kanchana Rueksomtawin; Juncker, Agnieszka; Hallstrom, Bjorn; Jensen, Niels Bjerg; Maury, Jerome; Nielsen, Jen; Förster, Jochen; Borodina, Irina

    sustainable alternative for production of acrylic acid from renewable feedstocks. We are establishing Saccharomyces cerevisiae as an alternative host for 3HP production. However, 3HP also inhibits yeast grow th at level well below what is desired for commercial applications. Therefore, we are aiming to...... improve 3HP tolerance in S. cerevisiae by applying adaptive evolution approach. We have generated yeast strains with sign ificantly improved capacity for tolerating 3HP when compared to the wild-type. We will present physiolo gical characterization, genome re-sequencing, and transcriptome analysis of the...

  8. Accumulation of gold using Baker's yeast, Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Authors have reported preconcentration of 152Eu, a long-lived fission product, by yeast cells, Saccharomyces cerevisiae. Gold being a precious metal is used in electroplating, hydrogenation catalyst, etc. Heterogeneous composition of samples and low concentration offers renewed interest in its selective extraction of gold using various extractants. Gold can be recovered from different solutions using various chemical reagents like amines, organophosphorus compounds, and extractants containing sulphur as donor atom, etc. In the present work, two different strains of baker's yeast, Saccharomyces cerevisiae have been used to study the preconcentration of gold at various experimental conditions

  9. Structure of Ynk1 from the yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    The crystal structure of Ynk1, an NDPK from the yeast Saccharomyces cerevisiae, has been solved at 3.1 Å resolution. Nucleoside diphosphate kinase (NDPK) catalyzes the transfer of the γ-phosphate from nucleoside triphosphates to nucleoside diphosphates. In addition to biochemical studies, a number of crystal structures of NDPK from various organisms, including both native proteins and complexes with nucleotides or nucleotide analogues, have been determined. Here, the crystal structure of Ynk1, an NDPK from the yeast Saccharomyces cerevisiae, has been solved at 3.1 Å resolution. Structural analysis strongly supports the oligomerization state of this protein being hexameric rather than tetrameric

  10. Induction of S.cerevisiae MAG 3-methyladenine DNA glycosylase transcript levels in response to DNA damage.

    OpenAIRE

    J. Chen; Samson, L

    1991-01-01

    We previously showed that the expression of the Saccharomyces cerevisiae MAG 3-methyladenine (3MeA) DNA glycosylase gene, like that of the E. coli alkA 3MeA DNA glycosylase gene, is induced by alkylating agents. Here we show that the MAG induction mechanism differs from that of alkA, at least in part, because MAG mRNA levels are not only induced by alkylating agents but also by UV light and the UV-mimetic agent 4-nitroquinoline-1-oxide. Unlike some other yeast DNA-damage-inducible genes, MAG ...

  11. Wetting reversal in colloid-polymer systems.

    Science.gov (United States)

    Blokhuis, Edgar M; Kuipers, Joris

    2010-05-01

    The wetting of a phase-separated colloid-polymer mixture in contact with a hard wall is analyzed using free volume theory in a Nakanishi-Fisher-type approach. We present results for the wetting phase diagram for several model approximations. Our analysis is compared with a previous analysis by Aarts [J. Chem. Phys. 120, 1973 (2004)]. We find that there is a crossover from wetting to drying at a threshold value for the colloid-polymer size ratio and that the transitions are close to the critical point and of second order in nature. PMID:20866234

  12. Modeling the pyrolysis of wet wood using FireFOAM

    International Nuclear Information System (INIS)

    Highlights: • Authors improve the pyrolysis model of wet wood considering oxidation and flame. • A simple one-step nth-order Arrhenius pyrolysis expression is employed. • The predicted results agree well with Shen et al.’s measured values in cone. • The gas mass fluxes are analyzed as a function of thickness and radiation flux. • The fitting correlations among the above three variables are obtained. - Abstract: A wet wood pyrolysis model was developed involving the combined influence of moisture, char oxidation, flame radiation and chemical reaction kinetics. Especially instead of multiple parallel reactions, a simple one-step nth-order Arrhenius expression for dry wood pyrolysis was combined with moisture drying reaction, which aimed at reducing the difficulty of obtaining kinetic and thermophysical parameters of intermediate solids. Code validation shows that the predicted surface temperature and total solid conversion ratio agree well with Shen et al.’s measured values in cone calorimeter under air atmosphere. The mass fluxes of water vapor and pyrolysate are analyzed as a function of wet wood thickness under various external radiation heat fluxes. The thickness has no effect on the maximum mass flux of vapor. The thickness of 8 mm is found to be the critical value with two peaks appearing simultaneously at pyrolysate mass flux profiles under 40 kW m−2. For the cases with two peaks of pyrolysate mass flux, the thickness has little effect on the time and value at the first peak of pyrolysate. However, those at second peak vary obviously with thickness. The fitting correlations of vapor duration and second pyrolysate flux peak time were also obtained

  13. Heterologous xylose isomerase pathway and evolutionary engineering improve xylose utilization in Saccharomyces cerevisiae.

    Science.gov (United States)

    Qi, Xin; Zha, Jian; Liu, Gao-Gang; Zhang, Weiwen; Li, Bing-Zhi; Yuan, Ying-Jin

    2015-01-01

    Xylose utilization is one key issue for the bioconversion of lignocelluloses. It is a promising approach to engineering heterologous pathway for xylose utilization in Saccharomyces cerevisiae. Here, we constructed a xylose-fermenting yeast SyBE001 through combinatorial fine-tuning the expression of XylA and endogenous XKS1. Additional overexpression of genes RKI1, RPE1, TKL1, and TAL1 in the non-oxidative pentose phosphate pathway (PPP) in SyBE001 increased the xylose consumption rate by 1.19-fold. By repetitive adaptation, the xylose utilization rate was further increased by ∼10-fold in the resultant strain SyBE003. Gene expression analysis identified a variety of genes with significantly changed expression in the PPP, glycolysis and the tricarboxylic acid cycle in SyBE003. PMID:26539187

  14. The utilization of some iron and zinc compounds as regulators of catalase activity at Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Efremova, N.

    2013-11-01

    Full Text Available The main aim of this study was to examine the impact of some zinc and iron compounds as oxidative stress factors on catalase activity, which is known to be important defense system of microorganisms to metal stress. For the investigation was used baker's yeast strain - Saccharomyces cerevisiae CNMN-Y-11 previously selected as a source of protein and catalase. The obtained results have revealed that compounds of iron and zinc with citrate and acetate contributes to the accumulation of yeast biomass and have beneficial effect on the catalase activity at selected yeast strain. The maximum increase of catalase activity in yeast biomass was established in case of iron and zinc citrate supplementation to the nutritive medium in optimal concentration of 15.0 mg/l. Results of the present study could be used for the elaboration of new procedures of catalase obtaining by directed synthesis with the utilization of selected metal compounds.

  15. Spacecraft Water Regeneration by Catalytic Wet Air Oxidation Project

    Data.gov (United States)

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

  16. Catalytic wet air oxidation of organic pollutants in waste waters

    OpenAIRE

    Gomes, Helder; Figueiredo, José; Boaventura, Rui; Faria, Joaquim

    2001-01-01

    Organic compounds are involved iii the manufacture of a wide variety of chemical products, generating in the process different kinds of liquid effluents with high chemical oxygen demand (COD) and high toxicity. Discharge of these waters without treatment into a river course is unacceptable, due to the toxic potential of some organic compounds or to depletion of the dissolved oxygen level, which can decrease below the level considered necessary to support aquatic life.

  17. Tualatin River - Wet Prairie Restoration Phase III

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Forty five acres of wet prairie and 11 acres of adjacent lands were treated for reed canarygrass in this ongoing project. Federally threatened Nelson’s...

  18. ROE Wet Nitrate Deposition 1989-1991

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet nitrate deposition in kilograms per hectare from 1989 to 1991. Summary data in this indicator were provided by EPA’s...

  19. ROE Wet Sulfate Deposition 2009-2011

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet sulfate deposition in kilograms per hectare from 2009 to 2011. Summary data in this indicator were provided by EPA’s...

  20. National Ignition Facility wet weather construction plan

    Energy Technology Data Exchange (ETDEWEB)

    Kugler, A N

    1998-01-01

    This report presents a wet weather construction plan for the National Ignition Facility (NIF) construction project. Construction of the NIF commenced in mid- 1997, and excavation of the site was completed in the fall. Preparations for placing concrete foundations began in the fall, and above normal rainfall is expected over the tinter. Heavy rainfall in late November impacted foundation construction, and a wet weather construction plan was determined to be needed. This wet weather constiction plan recommends a strategy, techniques and management practices to prepare and protect the site corn wet weather effects and allow construction work to proceed. It is intended that information in this plan be incorporated in the Stormwater Pollution Prevention Plan (SWPPP) as warranted.