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Sample records for oxidation processes aop

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

    PubMed

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

    2002-01-01

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

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

    PubMed

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

    2011-06-01

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

  3. ADVANCED OXIDATION PROCESSES (AOPS) FOR DESTRUCTION OF METHYL TERTIARY BUTYL ETHER (MTBE -AN UNREGULATED CONTAMINANT) IN DRINKING WATER

    EPA Science Inventory

    Advanced oxidation processes (AOPs) provide a promising treatment option for the destruction of MTBE directly in surface and ground waters. An ongoing study is evaluating the ability of three AOPs; hydrogen peroxide/ozone (H2O2/ O3), ultraviolet irradiation/ozone (UV/O3) and ultr...

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

    PubMed

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

    2016-07-01

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

  5. Heterogeneous Catalysis Applied To Advanced Oxidation Processes (AOPs) For Degradation of Organic Pollutants

    NASA Astrophysics Data System (ADS)

    Cotto-Maldonado, Maria del Carmen

    Water is an essencial resource for humankind and biomes. Actually, the pollution of the water resources, specially the contamination of the fresh water is great concern in our society. Develop of new and more efficient method for degradation of pollutant in water increase the research in this area, especially in the AOPs. During this investigation a comparison between different AOPs methods (photocatalysis, sono-Fenton and photo-Fenton) to determine the most efficient process of them was done. To reach our goal, different catalysts, namely TiO2 nanowires, TiO2 CNTs, ZnO nanoparticles, Fe2O3 nanowires and magnetite nanoparticles were synthesized and characterized by different techniques including FE-SEM, TGA, specific surface area (BET), XRD, Raman spectroscopy, XPS and magnetic susceptibility. Commercial and synthesized catalysts were used in photocatalysis, sono-Fenton and photo-Fenton processes for the degradation of model organic compounds (Methylene Blue, Rhodamine B, Methyl Orange, Gential Violet, Methyl Violet and p-aminobenzoic acid). According with the experimental results, no significant differences were observed between the photo-Fenton and sono-Fenton processes when the same catalysts were used. For the photocatalytic process, the more effective catalyst was TiO2NWs and for the sono-Fenton and photo-Fenton processes, the more effective catalyst was FeCl2.

  6. Biofilm control in water by advanced oxidation process (AOP) pre-treatment: effect of natural organic matter (NOM).

    PubMed

    Lakretz, Anat; Ron, Eliora Z; Harif, Tali; Mamane, Hadas

    2011-01-01

    The main goal of this study was to examine the influence of natural organic matter (NOM) on the efficiency of H₂O₂/UV advanced oxidation process (AOP) as a preventive treatment for biofilm control. Pseudomonas aeruginosa PAO1 biofilm-forming bacteria were suspended in water and exposed to various AOP conditions with different NOM concentrations, and compared to natural waters. H₂O₂/UV prevented biofilm formation: (a) up to 24 h post treatment - when residual H₂O₂ was neutralized; (b) completely (days) - when residual H₂O₂ was maintained. At high NOM concentrations (i.e. 25 mg/L NOM or 12.5 mg/L DOC) an additive biofilm control effect was observed for the combined H₂O₂/UV system compared to UV irradiation alone, after short biofilm incubation times (<24 h). This effect was H₂O₂ concentration dependent and can be explained by the high organic content of these water samples, whereby an increase in NOM could enhance (•)OH production and promote the formation of additional reactive oxygen species. In addition, maintaining an appropriate ratio of bacterial surviving conc.: residual H₂O₂ conc. post-treatment could prevent bacterial regrowth and biofilm formation.

  7. Iohexol degradation in wastewater and urine by UV-based Advanced Oxidation Processes (AOPs): Process modeling and by-products identification.

    PubMed

    Giannakis, Stefanos; Jovic, Milica; Gasilova, Natalia; Pastor Gelabert, Miquel; Schindelholz, Simon; Furbringer, Jean-Marie; Girault, Hubert; Pulgarin, César

    2016-07-11

    In this work, an Iodinated Contrast Medium (ICM), Iohexol, was subjected to treatment by 3 Advanced Oxidation Processes (AOPs) (UV, UV/H2O2, UV/H2O2/Fe(2+)). Water, wastewater and urine were spiked with Iohexol, in order to investigate the treatment efficiency of AOPs. A tri-level approach has been deployed to assess the UV-based AOPs efficacy. The treatment was heavily influenced by the UV transmittance and the organics content of the matrix, as dilution and acidification improved the degradation but iron/H2O2 increase only moderately. Furthermore, optimization of the treatment conditions, as well as modeling of the degradation was performed, by step-wise constructed quadratic or product models, and determination of the optimal operational regions was achieved through desirability functions. Finally, global chemical parameters (COD, TOC and UV-Vis absorbance) were followed in parallel with specific analyses to elucidate the degradation process of Iohexol by UV-based AOPs. Through HPLC/MS analysis the degradation pathway and the effects the operational parameters were monitored, thus attributing the pathways the respective modifications. The addition of iron in the UV/H2O2 process inflicted additional pathways beneficial for both Iohexol and organics removal from the matrix.

  8. Degradation of diethyl phthalate in treated effluents from an MBR via advanced oxidation processes: effects of nitrate on oxidation and a pilot-scale AOP operation.

    PubMed

    Park, J H; Park, C G; Lee, J W; Ko, K B

    2010-01-01

    The major objective of this study was to delineate the oxidation of diethyl phthalate (DEP) in water, using bench-scale UV/H2O2 and O3/H2O2 processes, and to determine the effects of nitrate (NO(3-)-N, 5 mg L(-1)) on this oxidation. The oxidation of DEP was also investigated through a pilot-scale advanced oxidation process (AOP), into which a portion of the effluent from a pilot-scale membrane bioreactor (MBR) plant was pumped. The bench-scale operation showed that DEP could be oxidized via solely UV oxidation or O3 oxidation. The adverse effect of nitrate on the DEP oxidation was remarkable in the UV/H2O2 process, and the nitrate clearly reduced its oxidation. The adverse effect of nitrate on O3 oxidation was also observed. It was noted, however, that the nitrate clearly enhanced the DEP oxidation in the O3/H2O2 process. A series of pilot-scale AOP operations indicated that the addition of H2O2 enhanced DEP oxidation in both the UV/H2O2 and O3/H2O2 processes. No noticeable adverse effect of nitrate was observed in the NO(3-)-N concentration of about 6.0 mg L(-1), which was naturally contained in the treatment stream. About 52% and 61% of the DEP were oxidized by each of these two oxidation processes in this pilot-scale operation. Both the UV/H2O2 and O3/H2O2 processes appeared to be desirable alternatives for DEP oxidation in treatment effluent streams.

  9. Overview of the PCDD/Fs degradation potential and formation risk in the application of advanced oxidation processes (AOPs) to wastewater treatment.

    PubMed

    Vallejo, Marta; Fresnedo San Román, M; Ortiz, Inmaculada; Irabien, Angel

    2015-01-01

    Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are a family of unintentionally produced persistent organic pollutants (POPs) that have received considerable public and scientific attention due to the toxicity of some of their congeners, more specifically those with chlorine substitution in the 2,3,7,8 positions. The environmental management and control of PCDD/Fs is addressed at a global level through the Stockholm Convention that establishes that POPs should be destroyed or irreversibly transformed in order to reduce or eliminate their release to the environment. Several technologies, including advanced oxidation processes (AOPs) such as photolysis, photocatalysis and Fenton oxidation, have been considered as effective methods for destroying PCDD/Fs in polluted waters. Nevertheless, during the remediation of wastewaters it is critical that the treatment technologies applied do not lead to the formation of by-products that are themselves POPs, especially if PCDD/Fs precursors or chlorine are present in the reaction medium. Despite the high effectiveness of AOPs in the oxidation of major contaminants, scarce references deal with the monitoring of PCDD/Fs in the course of the oxidation process, revealing that a detailed assessment of non-combustion technologies with respect to PCDD/Fs formation is still lacking. This study reports a review of the state of the art related to the potential remediation and/or formation of PCDD/Fs as a result of the application of AOPs for the treatment of polluted waters, warning on the correct selection of the operating conditions.

  10. Sulfate radical-advanced oxidation process (SR-AOP) for simultaneous removal of refractory organic contaminants and ammonia in landfill leachate.

    PubMed

    Deng, Yang; Ezyske, Casey M

    2011-11-15

    Typically, a mature landfill leachate contains high levels of non-biodegradable organics and ammonia nitrogen. Simultaneous removal of the both persistent leachate pollutants is a significant challenge. This paper reports the first scientific study to apply a sulfate radical (SO(4)(·-)) - based advanced oxidation process (SR-AOP) to treat a mature leachate, with an emphasis of concurrent removal of refractory organics and ammonia. In this study, all the experiments were run in a batch reactor with temperature control. In the thermal persulfate oxidation (TPO) process, persulfate (S(2)O(8)(2-)) was activated by heat to produce powerful oxidants, SO(4)(·-) (E(o) = 2.6 V). Three factors affecting the removal efficiencies of chemical oxygen demand (COD) and ammonia nitrogen were investigated, including initial solution pH (3-8.3), temperature (27-50 °C), and chemical dose (S(2)O(8)(2-):12COD(0) = 0.25-2.0). Typically, acidic pH (3-4), higher temperature, and higher dose favored the removal of COD and ammonia. At S(2)O(8)(2-):12COD(0) = 2 and 50 °C, the COD removal rates were 79% and 91% at pH 8.3 (no pH adjustment) and 4, respectively; and the ammonia nitrogen removal reached 100% at pH 8.3 or 4. SR-AOP appears to be more advantageous over hydroxyl radical (OH∙)-based advanced oxidation processes (HR-AOPs) because OH∙ almost does not oxidize ammonia. Furthermore, compared with Fenton treatment of the same batch leachate sample, the TPO could achieve a higher COD removal at an identical chemical dose. For example, COD removal was 40% at H(2)O(2):2.125COD(0) = 2 during Fenton treatment (pH 3), but 91% at S(2)O(8)(2-):12COD(0) = 2 during TPO (pH 4). These findings demonstrate that SR-AOP is a promising landfill leachate treatment method.

  11. Comparison of halide impacts on the efficiency of contaminant degradation by sulfate and hydroxyl radical-based advanced oxidation processes (AOPs).

    PubMed

    Yang, Yi; Pignatello, Joseph J; Ma, Jun; Mitch, William A

    2014-02-18

    The effect of halides on organic contaminant destruction efficiency was compared for UV/H2O2 and UV/S2O8(2-) AOP treatments of saline waters; benzoic acid, 3-cyclohexene-1-carboxylic acid, and cyclohexanecarboxylic acid were used as models for aromatic, alkene, and alkane constituents of naphthenic acids in oil-field waters. In model freshwater, contaminant degradation was higher by UV/S2O8(2-) because of the higher quantum efficiency for S2O8(2-) than H2O2 photolysis. The conversion of (•)OH and SO4(•-) radicals to less reactive halogen radicals in the presence of seawater halides reduced the degradation efficiency of benzoic acid and cyclohexanecarboxylic acid. The UV/S2O8(2-) AOP was more affected by Cl(-) than the UV/H2O2 AOP because oxidation of Cl(-) is more favorable by SO4(•-) than (•)OH at pH 7. Degradation of 3-cyclohexene-1-carboxylic acid, was not affected by halides, likely because of the high reactivity of halogen radicals with alkenes. Despite its relatively low concentration in saline waters compared to Cl(-), Br(-) was particularly important. Br(-) promoted halogen radical formation for both AOPs resulting in ClBr(•-), Br2(•-), and CO3(•-) concentrations orders of magnitude higher than (•)OH and SO4(•-) concentrations and reducing differences in halide impacts between the two AOPs. Kinetic modeling of the UV/H2O2 AOP indicated a synergism between Br(-) and Cl(-), with Br(-) scavenging of (•)OH leading to BrOH(•-), and further reactions of Cl(-) with this and other brominated radicals promoting halogen radical concentrations. In contaminant mixtures, the conversion of (•)OH and SO4(•-) radicals to more selective CO3(•-) and halogen radicals favored attack on highly reactive reaction centers represented by the alkene group of 3-cyclohexene-1-carboxylic acid and the aromatic group of the model compound, 2,4-dihydroxybenzoic acid, at the expense of less reactive reaction centers such as aromatic rings and alkane groups

  12. Advanced H2O2 oxidation for diethyl phthalate degradation in treated effluents: effect of nitrate on oxidation and a pilot-scale AOP operation.

    PubMed

    Ko, K B; Park, C G; Moon, T H; Ahn, Y H; Lee, J K; Ahn, K H; Park, J H; Yeom, I T

    2008-01-01

    One of the objectives of this study was to delineate the effect of nitrate on diethyl phthalate (DEP) oxidation by conducting a bench-scale ultraviolet (UV)/H2O2 and O3/H2O2 operations as suggested in a previous study. We also aim to investigate DEP oxidation at various UV doses and H2O2 concentrations by performing a pilot-scale advanced oxidation processes (AOP) system, into which a portion of the effluent from a pilot-scale membrane bioreactor (MBR) plant was pumped. In the bench-scale AOP operation, the O3 oxidation alone as well as the UV irradiation without H2O2 addition could be among the desirable alternatives for the efficient removal of DEP dissolved in aqueous solutions at a low DEP concentration range of 85+/-15 microg/L. The adverse effect in the UV/H2O2 process was significantly greater than that in the UV oxidation alone, and its oxidation was almost halved by the nitrate. However, the nitrate clearly enhanced the DEP oxidation in the O3 oxidation and O3/H2O2 process. Especially, the addition of nitrate almost doubled the DEP oxidation efficiency in the O3/H2O2 process. The series of pilot-scale AOP operations confirmed that about 30-50% of DEP dissolved in the treated MBR effluent streams was, at least, oxidized by the O3 oxidation alone as well as the UV irradiation without H2O2 addition. The UV photolysis of H2O2 was most effective for DEP degradation with an H2O2 concentration of 40 mg/L at a UV dose of 500 mJ/cm2.

  13. Decomposition of phenylarsonic acid by AOP processes: degradation rate constants and by-products.

    PubMed

    Jaworek, K; Czaplicka, M; Bratek, Ł

    2014-10-01

    The paper presents results of the studies photodegradation, photooxidation, and oxidation of phenylarsonic acid (PAA) in aquatic solution. The water solutions, which consist of 2.7 g dm(-3) phenylarsonic acid, were subjected to advance oxidation process (AOP) in UV, UV/H2O2, UV/O3, H2O2, and O3 systems under two pH conditions. Kinetic rate constants and half-life of phenylarsonic acid decomposition reaction are presented. The results from the study indicate that at pH 2 and 7, PAA degradation processes takes place in accordance with the pseudo first order kinetic reaction. The highest rate constants (10.45 × 10(-3) and 20.12 × 10(-3)) and degradation efficiencies at pH 2 and 7 were obtained at UV/O3 processes. In solution, after processes, benzene, phenol, acetophenone, o-hydroxybiphenyl, p-hydroxybiphenyl, benzoic acid, benzaldehyde, and biphenyl were identified.

  14. Induced effects of advanced oxidation processes.

    PubMed

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

    2014-02-07

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

  15. Induced effects of advanced oxidation processes

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  16. The Role of Ultrasound on Advanced Oxidation Processes.

    PubMed

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

    2016-10-01

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

  17. Destruction of microcystins (cyanotoxins) by UV-254 nm-based direct photolysis and advanced oxidation processes (AOPs): influence of variable amino acids on the degradation kinetics and reaction mechanisms.

    PubMed

    He, Xuexiang; de la Cruz, Armah A; Hiskia, Anastasia; Kaloudis, Triantafyllos; O'Shea, Kevin; Dionysiou, Dionysios D

    2015-05-01

    Hepatotoxic microcystins (MCs) are the most frequently detected group of cyanobacterial toxins. This study investigated the degradation of common MC variants in water, MC-LR, MC-RR, MC-YR and MC-LA, by UV-254 nm-based processes, UV only, UV/H2O2, UV/S2O8(2-) and UV/HSO5(-). Limited direct photolysis of MCs was observed, while the addition of an oxidant significantly improved the degradation efficiency with an order of UV/S2O8(2-) > UV/HSO5(-) > UV/H2O2 at the same initial molar concentration of the oxidant. The removal of MC-LR by UV/H2O2 appeared to be faster than another cyanotoxin, cylindrospermopsin, at either the same initial molar concentration or the same initial organic carbon concentration of the toxin. It suggested a faster reaction of MC-LR with hydroxyl radical, which was further supported by the determined second-order rate constant of MCs with hydroxyl radical. Both isomerization and photohydration byproducts were observed in UV only process for all four MCs; while in UV/H2O2, hydroxylation and diene-Adda double bond cleavage byproducts were detected. The presence of a tyrosine in the structure of MC-YR significantly promoted the formation of monohydroxylation byproduct m/z 1061; while the presence of a second arginine in MC-RR led to the elimination of a guanidine group and the absence of double bond cleavage byproducts. It was therefore demonstrated in this study that the variable amino acids in the structure of MCs influenced not only the degradation kinetics but also the preferable reaction mechanisms.

  18. Applicability of fluidized bed reactor in recalcitrant compound degradation through advanced oxidation processes: a review.

    PubMed

    Tisa, Farhana; Abdul Raman, Abdul Aziz; Wan Daud, Wan Mohd Ashri

    2014-12-15

    Treatment of industrial waste water (e.g. textile waste water, phenol waste water, pharmaceutical etc) faces limitation in conventional treatment procedures. Advanced oxidation processes (AOPs) do not suffer from the limits of conventional treatment processes and consequently degrade toxic pollutants more efficiently. Complexity is faced in eradicating the restrictions of AOPs such as sludge formation, toxic intermediates formation and high requirement for oxidants. Increased mass-transfer in AOPs is an alternate solution to this problem. AOPs combined with Fluidized bed reactor (FBR) can be a potential choice compared to fixed bed or moving bed reactor, as AOP catalysts life-span last for only maximum of 5-10 cycles. Hence, FBR-AOPs require lesser operational and maintenance cost by reducing material resources. The time required for AOP can be minimized using FBR and also treatable working volume can be increased. FBR-AOP can process from 1 to 10 L of volume which is 10 times more than simple batch reaction. The mass transfer is higher thus the reaction time is lesser. For having increased mass transfer sludge production can be successfully avoided. The review study suggests that, optimum particle size, catalyst to reactor volume ratio, catalyst diameter and liquid or gas velocity is required for efficient FBR-AOP systems. However, FBR-AOPs are still under lab-scale investigation and for industrial application cost study is needed. Cost of FBR-AOPs highly depends on energy density needed and the mechanism of degradation of the pollutant. The cost of waste water treatment containing azo dyes was found to be US$ 50 to US$ 500 per 1000 gallons where, the cost for treating phenol water was US$ 50 to US$ 800 per 1000 gallons. The analysis for FBR-AOP costs has been found to depend on the targeted pollutant, degradation mechanism (zero order, 1st order and 2nd order) and energy consumptions by the AOPs.

  19. Adverse Outcome Pathway (AOP) Network Development for ...

    EPA Pesticide Factsheets

    Adverse outcome pathways (AOPs) are descriptive biological sequences that start from a molecular initiating event (MIE) and end with an adverse health outcome. AOPs provide biological context for high throughput chemical testing and further prioritize environmental health risk research. According to the Organization for Economic Co-operation and Development guidelines, AOPs are pathways with one MIE anchored to an adverse outcome (AO) by key events (KEs) and key event relationships (KERs). However, this approach does not always capture the cumulative impacts of multiple MIEs on the AO. For example, hepatic lipid flux due to chemical-induced toxicity initiates from multiple ligand-activated receptors and signaling pathways that cascade across biology to converge upon a common fatty liver (FL, also known as steatosis) outcome. To capture this complexity, a top-down strategy was used to develop a FL AOP network (AOPnet). Literature was queried based on the terms steatosis, fatty liver, cirrhosis, and hepatocellular carcinoma. Search results were analyzed for physiological and pathophysiological organ level, cellular and molecular processes, as well as pathway intermediates, to identify potential KEs and MIEs that are key for hepatic lipid metabolism, maintenance, and dysregulation. The analysis identified four apical KE nodes (hepatic fatty acid uptake, de novo fatty acid and lipid synthesis, fatty acid oxidation, and lipid efflux) juxtaposed to the FL AO. The apic

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

    EPA Science Inventory

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

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

    PubMed

    Zhihui, Ai; Peng, Yang; Xiaohua, Lu

    2005-08-01

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

  2. Degradation of formaldehyde by advanced oxidation processes.

    PubMed

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

    2012-09-30

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

  3. Oxidative degradation of endotoxin by advanced oxidation process (O3/H2O2 & UV/H2O2).

    PubMed

    Oh, Byung-Taek; Seo, Young-Suk; Sudhakar, Dega; Choe, Ji-Hyun; Lee, Sang-Myeong; Park, Youn-Jong; Cho, Min

    2014-08-30

    The presence of endotoxin in water environments may pose a serious public health hazard. We investigated the effectiveness of advanced oxidative processes (AOP: O3/H2O2 and UV/H2O2) in the oxidative degradation of endotoxin. In addition, we measured the release of endotoxin from Escherichia coli following typical disinfection methods, such as chlorine, ozone alone and UV, and compared it with the use of AOPs. Finally, we tested the AOP-treated samples in their ability to induce tumor necrosis factor alpha (TNF-α) in mouse peritoneal macrophages. The production of hydroxyl radical in AOPs showed superior ability to degrade endotoxin in buffered solution, as well as water samples from Korean water treatment facilities, with the ozone/H2O2 being more efficient compared to UV/H2O2. In addition, the AOPs proved effective not only in eliminating E. coli in the samples, but also in endotoxin degradation, while the standard disinfection methods lead to the release of endotoxin following the bacteria destruction. Furthermore, in the experiments with macrophages, the AOPs-deactivated endotoxin lead to the smallest induction of TNF-α, which shows the loss of inflammation activity, compared to ozone treatment alone. In conclusion, these results suggest that AOPs offer an effective and mild method for endotoxin degradation in the water systems.

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

    PubMed

    Kraft, Alexander; Stadelmann, Manuela; Blaschke, Manfred

    2003-10-31

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

  5. Improvement of DOC removal by multi-stage AOP-biological treatment.

    PubMed

    Fahmi; Nishijima, Wataru; Okada, Mitsumasa

    2003-03-01

    The single and multi-stages advanced oxidation process (AOP)-biological treatments were evaluated to apply for drinking water treatment, especially for the water containing less susceptible dissolved organic carbon (DOC) to ozone, comparing with the ozonation-biological treatment. Minaga reservoir water and the secondary effluent from a Municipal wastewater treatment plant were used as dissolved organic matter (DOM) solutions. DOC removals after 60 min AOP-biological treatment were 62% and 41% in the Minaga reservoir water and the secondary effluent, respectively, whereas those in the ozonation-biological treatment only 40% and 15% of DOC were removed, respectively. The result indicated that the single-stage AOP-biological treatment could improve DOC removal in comparison with the single-stage ozonation-biological treatment. This is because the AOP mineralized both biodegradable dissolved organic carbon (BDOC) produced in the early stage of oxidation and non-biodegradable dissolved organic carbon (NBDOC), whereas only BDOC was mineralized by further ozonation and NBDOC was not oxidized in the ozonation-biological treatment. The multi-stage treatment could not improve DOC removal in comparison with the single-stage treatment in the ozonation-biological treatment for the secondary effluent containing less susceptible DOC to ozone. However, the multi-stage AOP-biological treatment significantly reduced DOC and achieved 71% of DOC removal by 4 times repetition of 15 min oxidation, whereas DOC removal was 41% in the single-stage AOP-biological treatment for the same oxidation time. The improvement of DOC removal by the multi-stage AOP-biological treatment was due to BDOC removal as a radical scavenger by subsequent biological treatment in the early stage of oxidation and direct mineralization in the latter stage of oxidation.

  6. Accelerating Adverse Outcome Pathway (AOP) development ...

    EPA Pesticide Factsheets

    The Adverse Outcome Pathway (AOP) framework is increasingly being adopted as a tool for organizing and summarizing the mechanistic information connecting molecular perturbations by environmental stressors with adverse outcomes relevant for ecological and human health outcomes. However, the conventional process for assembly of these AOPs is time and resource intensive, and has been a rate limiting step for AOP use and development. Therefore computational approaches to accelerate the process need to be developed. We previously developed a method for generating computationally predicted AOPs (cpAOPs) by association mining and integration of data from publicly available databases. In this work, a cpAOP network of ~21,000 associations was established between 105 phenotypes from TG-GATEs rat liver data from different time points (including microarray, pathological effects and clinical chemistry data), 994 REACTOME pathways, 688 High-throughput assays from ToxCast and 194 chemicals. A second network of 128,536 associations was generated by connecting 255 biological target genes from ToxCast to 4,980 diseases from CTD using either HT screening activity from ToxCast for 286 chemicals or CTD gene expression changes in response to 2,330 chemicals. Both networks were separately evaluated through manual extraction of disease-specific cpAOPs and comparison with expert curation of the relevant literature. By employing data integration strategies that involve the weighting of n

  7. Combining Advanced Oxidation Processes: Assessment Of Process Additivity, Synergism, And Antagonism

    SciTech Connect

    Peters, Robert W.; Sharma, M.P.; Gbadebo Adewuyi, Yusuf

    2007-07-01

    This paper addresses the process interactions from combining integrated processes (such as advanced oxidation processes (AOPs), biological operations, air stripping, etc.). AOPs considered include: Fenton's reagent, ultraviolet light, titanium dioxide, ozone (O{sub 3}), hydrogen peroxide (H{sub 2}O{sub 2}), sonication/acoustic cavitation, among others. A critical review of the technical literature has been performed, and the data has been analyzed in terms of the processes being additive, synergistic, or antagonistic. Predictions based on the individual unit operations are made and compared against the behavior of the combined unit operations. The data reported in this paper focus primarily on treatment of petroleum hydrocarbons and chlorinated solvents. (authors)

  8. Evaluation of the relationship between bulk organic precursors and disinfection byproduct formation for advanced oxidation processes.

    PubMed

    Mayer, Brooke K; Daugherty, Erin; Abbaszadegan, Morteza

    2015-02-01

    Advanced oxidation processes (AOPs) are gaining traction as they offer mineralization potential rather than transferring contaminants between media. However, AOPs operated with limited energy and/or chemical inputs can exacerbate disinfection byproduct (DBP) formation, even as precursors such as dissolved organic carbon, UV254, and specific UV absorbance (SUVA) decrease. This study examined the relationship between DBP precursors and formation using TiO2 photocatalysis experiments, external AOP and non-AOP data, and predictive DBP models. The top-performing indicator, SUVA, generally correlated positively with trihalomethanes and haloacetic acids, but limited-energy photocatalysis yielded contrasting negative correlations. The accuracy of predicted DBP values from models based on bulk parameters was generally poor, regardless of use and extent of AOP treatment and type of source water. Though performance improved for scenarios bounded by conditions used in model development, only 0.5% of the model/dataset pairings satisfied all measured parameter boundary conditions, thereby introducing skepticism toward model usefulness. Study findings suggest that caution should be employed when using bulk indicators and/or models as a metric for AOP mitigation of DBP formation potential, particularly for limited-energy/chemical inputs.

  9. Comprehensive study on effects of water matrices on removal of pharmaceuticals by three different kinds of advanced oxidation processes.

    PubMed

    Tokumura, Masahiro; Sugawara, Asato; Raknuzzaman, Mohammad; Habibullah-Al-Mamun, Md; Masunaga, Shigeki

    2016-09-01

    Simple semi-theoretical models were developed to estimate the performance of three different kinds of advanced oxidation processes (AOPs) in the degradation of pharmaceuticals. The AOPs included the photo-Fenton process as an example of a liquid-liquid reaction, the TiO2 photocatalytic oxidation process as a solid-liquid reaction, and the combined ozone and hydrogen peroxide oxidation process as a gas-liquid reaction; the effects of the aqueous matrices (CESs: co-existing substances) of actual wastewater on the removal of pharmaceuticals (carbamazepine and diclofenac) was taken into account. By comparing the characteristic parameters of the models, obtained from the experiments using pure water and actual wastewater, the effects of CESs on the respective removal mechanisms could be separately and quantitatively evaluated. As a general tendency, the AOPs proceeded less effectively (were inhibited) in the matrices containing CESs, as observed with the use of a lower initial concentration of pharmaceuticals. The inhibition mechanisms differed for the three types of AOPs. In the photo-Fenton process, the Fenton reaction was improved by the incorporation of CESs, while the photo-reduction reaction was significantly inhibited. In the TiO2 photocatalytic oxidation process, competition between the pharmaceuticals and CESs for adsorption on the catalyst surface was a less significant inhibitory factor than the scavenger effects of the CESs. The combined ozone and hydrogen peroxide oxidation process was most strongly inhibited by CESs among the AOPs investigated in this study.

  10. Pretreatment of whole blood using hydrogen peroxide and UV irradiation. Design of the advanced oxidation process.

    PubMed

    Bragg, Stefanie A; Armstrong, Kristie C; Xue, Zi-Ling

    2012-08-15

    A new process to pretreat blood samples has been developed. This process combines the Advanced Oxidation Process (AOP) treatment (using H(2)O(2) and UV irradiation) with acid deactivation of the enzyme catalase in blood. A four-cell reactor has been designed and built in house. The effect of pH on the AOP process has been investigated. The kinetics of the pretreatment process shows that at high C(H(2)O(2),t=0), the reaction is zeroth order with respect to C(H(2)O(2)) and first order with respect to C(blood). The rate limiting process is photon flux from the UV lamp. Degradation of whole blood has been compared with that of pure hemoglobin samples. The AOP pretreatment of the blood samples has led to the subsequent determination of chromium and zinc concentrations in the samples using electrochemical methods.

  11. The effect of combination enzymatic and advanced oxidation process treatments on the colour of pulp and paper mill effluent.

    PubMed

    Karimi, Samaneh; Abdulkhani, Ali; Karimi, Alinaghi; Ghazali, Abdul Halim B; Ahmadun, Fakhru L-Razi

    2010-04-01

    The efficiency of advanced oxidation processes (AOPs), enzymatic treatment and combined enzymatic/AOP sequences for the colour remediation of soda and chemimechanical pulp and paper mill effluent was investigated. The results indicated that under all circumstances, the AOP using ultraviolet irradiation (photo-Fenton) was more efficient in the degradation of effluent components in comparison with the dark reaction. It was found that both versatile peroxidase (VP) from Bjerkandera adusta and laccase from Trametes versicolor, as pure enzymes, decolorize the deep brown effluent to a clear light-yellow solution. In addition, it was found that in the laccase treatment, the decolorization rates of both effluents were enhanced in the presence of 2, 2'-azinobis (3-ethylbenzthiazoline-6-sulfonate), while in the case of VP, Mn(+2) decreased the efficiency of the decolorization treatment. The concomitant use of enzymes and AOPs imposes a considerable effect on the colour remediation of effluent samples.

  12. Immunohistochemical detection of metalloproteinase-9 (MMP-9), anti-oxidant like 1 protein (AOP-1) and synaptosomal-associated protein (SNAP-25) in the cerebella of dogs naturally infected with spontaneous canine distemper.

    PubMed

    Bregano, Lívia C; Agostinho, Sabrina D; Roncatti, Flávio L B T; Pires, Marcília C; Riva, Henrique G; Luvizotto, Maria C R; Cardoso, Tereza C

    2011-01-01

    In most viral infections of the central nervous system (CNS), the integrity of brain extracelluar matrix (ECM), oxidative stress and dysfunction in neuronal transmission may contribute to the observed pathology. The purpose of this study was to investigate the role of these factors in demyelinating canine distemper virus (CDV) infections. Regardless of ECM integrity, the expression of metalloproteinase-9 (MMP-9) was visualized in microglial-like cells, whereas the expression of anti-oxidant like-1 (AOP-1) and synaptosomal associated protein (SNAP-25) was frequently detected in Purkinje cells (r(2) = 0.989; p < 0.05), regardless of whether the lesions were classified as acute or chronic. Increased numbers of immunolabeled microglia-like cells and reactive gliosis were observed in advanced cases of demyelinating CDV, suggesting that the expression of AOP-1 and SNAP-25 is correlated with the ultimate death of affected cells. Our findings bring a new perspective to understanding the role of the AOP-1, MMP-9 and SNAP-25 proteins in mediating chronic leukoencephalitis caused by CDV.

  13. Formation of nitroaromatic compounds in advanced oxidation processes: Photolysis versus photocatalysis

    SciTech Connect

    Dzengel, J.; Theurich, J.; Bahnemann, D.W.

    1999-01-15

    There is a growing demand for efficient treatment of organic polluted wastewaters by advanced oxidation processes (AOPs). Besides optimization of the processes, the detailed understanding of degradation mechanisms and interactions of organic pollutants with inorganic substrates is important for technical applications of AOPs. Therefore, the aim of the present study was to investigate the influence of nitrate ions on the photooxidation of phenol for various AOPs at different pH values. Three different oxidation processes were compared in these studies: direct photolysis, TiO{sub 2}/UV, and H{sub 2}O{sub 2}/UV. Special emphasis has been laid on the analysis of byproducts especially on the formation of nitroaromatic compounds. The formation of intermediates as well as the depletion of phenol were monitored by HPLC technique. The total organic carbon content, TOC, was measured to monitor the mineralization. Highest degradation rates and lowest concentrations of intermediates were observed with TiO{sub 2}/UV being the AOP. Formation of highly toxic nitrophenols was only observed when homogeneous AOPs were employed. For the TiO{sub 2}/UV process no formation of Nitroaromatic byproducts occurred. At pH 5 formation of nitrophenols was observed employing direct photolysis in the presence of NO{sub 2}{sup {minus}}, while with H{sub 2}O{sub 2}/UV nitrophenols were detected only when the concentration of NO{sub 2}{sup {minus}} was higher than that of H{sub 2}O{sub 2}. At pH 11 no nitroaromatic intermediates were found for any AOPs compared in this study.

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

    PubMed

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

    2007-05-01

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

  15. The 2010 AOP Workshop Summary Report

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B.; Morrow, John H.; Brown, James W.; Firestone, Elaine R.

    2011-01-01

    The rationale behind the current workshop, which was hosted by Biospherical Instruments Inc. (BSI), was to update the community and get community input with respect to the following: topics not addressed during the first workshop, specifically the processing of above-water apparent optical property (AOP data) within the Processing of Radiometric Observations of Seawater using Information Technologies (PROSIT) architecture; PROSIT data processing issues that have developed or tasks that have been completed, since the first workshop; and NASA instrumentation developments, both above- and in-water, that are relevant to both workshops and next generation mission planning. The workshop emphasized presentations on new AOP instrumentation, desired and required features for processing above-water measurements of the AOPs of seawater, working group discussions, and a community update for the in-water data processing already present in PROSIT. The six working groups were organized as follows: a) data ingest and data products; b) required and desired features for optically shallow and optically deep waters; c) contamination rejection (clouds), corrections, and data filtering; d) sun photometry and polarimetry; e) instrumentation networks; and f) hyperspectral versus fixed-wavelength sensors. The instrumentation networks working group was intended to provide more detailed information about desired and required features of autonomous sampling systems. Plenary discussions produced a number of recommendations for evolving and documenting PROSIT.

  16. Comparison of different advanced oxidation process to reduce toxicity and mineralisation of tannery wastewater.

    PubMed

    Schrank, S G; José, H J; Moreira, R F P M; Schröder, H Fr

    2004-01-01

    Many organic compounds contained in wastewater are resistant to conventional chemical and/or biological treatment. Because of this reason different degradation techniques are studied as an alternative to biological and classical physico-chemical processes. Advanced Oxidation Processes (AOPs) probably have developed to become the best options in the near future. AOP while making use of different reaction systems, are all characterised by the same chemical feature: production of OH radicals (*OH). The versatility of AOPs is also enhanced by the fact that they offer different possibilities for OH radical production, thus allowing them to conform to specific treatment requirements. The main problem with AOPs is their high cost. The application of solar technologies to these processes could help to diminish that problem by reducing the energy consumption required for generating UV radiation. In this work, different AOPs (O3, TiO2/UV, Fenton and H2O2/UV) were examined to treat tannery wastewater or as a pre-treatment step for improving the biodegradation of tannery wastewater, at different pH and dosage of the chemicals. Under certain circumstances retardation in biodegradation and/or an increase in toxicity may be observed within these treatment steps. Two different bioassays (Daphnia magna and Vibrio fischeri) have been used for testing the progress of toxicity during the treatment. In parallel other objectives were to analyse and identify organic compounds present in the untreated wastewater and arising degradation products in AOP treated wastewater samples. For this purpose substance specific techniques, e.g., gas chromatography-mass spectrometry (GC-MS) in positive electron impact (El(+)) mode and atmospheric pressure ionisation (API) in combination with flow injection analysis (FIA) or liquid chromatography-mass and tandem mass spectrometry (LC-MS or LC-MS-MS) were performed.

  17. A comparison of the environmental impact of different AOPs: risk indexes.

    PubMed

    Giménez, Jaime; Bayarri, Bernardí; González, Óscar; Malato, Sixto; Peral, José; Esplugas, Santiago

    2014-12-31

    Today, environmental impact associated with pollution treatment is a matter of great concern. A method is proposed for evaluating environmental risk associated with Advanced Oxidation Processes (AOPs) applied to wastewater treatment. The method is based on the type of pollution (wastewater, solids, air or soil) and on materials and energy consumption. An Environmental Risk Index (E), constructed from numerical criteria provided, is presented for environmental comparison of processes and/or operations. The Operation Environmental Risk Index (EOi) for each of the unit operations involved in the process and the Aspects Environmental Risk Index (EAj) for process conditions were also estimated. Relative indexes were calculated to evaluate the risk of each operation (E/NOP) or aspect (E/NAS) involved in the process, and the percentage of the maximum achievable for each operation and aspect was found. A practical application of the method is presented for two AOPs: photo-Fenton and heterogeneous photocatalysis with suspended TiO2 in Solarbox. The results report the environmental risks associated with each process, so that AOPs tested and the operations involved with them can be compared.

  18. Novel imazethapyr detoxification applying advanced oxidation processes.

    PubMed

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

    2011-01-01

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

  19. Advanced oxidation process using hydrogen peroxide/microwave system for solubilization of phosphate.

    PubMed

    Liao, Ping Huang; Wong, Wayne T; Lo, Kwang Victor

    2005-01-01

    An advanced oxidation process (AOP) combining hydrogen peroxide and microwave heating was used for the solubilization of phosphate from secondary municipal sludge from an enhanced biological phosphorus removal process. The microwave irradiation is used as a generator agent of oxidizing radicals as well as a heating source in the process. This AOP process could facilitate the release of a large amount of the sludge-bound phosphorus from the sewage sludge. More than 84% of the total phosphorous could be released at a microwave heating time of 5 min at 170 degrees C. This innovative process has the potential of being applied to simple sludge treatment processes in domestic wastewater treatment and to the recovery of phosphorus from the wastewater.

  20. Giardia duodenalis: Number and Fluorescence Reduction Caused by the Advanced Oxidation Process (H2O2/UV)

    PubMed Central

    Guimarães, José Roberto; Franco, Regina Maura Bueno; Guadagnini, Regiane Aparecida; dos Santos, Luciana Urbano

    2014-01-01

    This study evaluated the effect of peroxidation assisted by ultraviolet radiation (H2O2/UV), which is an advanced oxidation process (AOP), on Giardia duodenalis cysts. The cysts were inoculated in synthetic and surface water using a concentration of 12 g H2O2 L−1 and a UV dose (λ = 254 nm) of 5,480 mJcm−2. The aqueous solutions were concentrated using membrane filtration, and the organisms were observed using a direct immunofluorescence assay (IFA). The AOP was effective in reducing the number of G. duodenalis cysts in synthetic and surface water and was most effective in reducing the fluorescence of the cyst walls that were present in the surface water. The AOP showed a higher deleterious potential for G. duodenalis cysts than either peroxidation (H2O2) or photolysis (UV) processes alone. PMID:27379301

  1. Enhancement of Electron Transfer in Various Photo-Assisted Oxidation Processes for Nitro-Phenolic Compound Conversion

    NASA Astrophysics Data System (ADS)

    Khue, Do Ngoc; Lam, Tran Dai; Minh, Do Binh; Loi, Vu Duc; Nam, Nguyen Hoai; Bach, Vu Quang; Van Anh, Nguyen; Van Hoang, Nguyen; Hu'ng, Dao Duy

    2016-08-01

    The present study focuses on photo-assisted advanced oxidation processes (AOPs) with strongly enhanced electron transfer for degradation of nitro-phenolic compounds in aqueous medium. The effectiveness of these processes was estimated based on the pseudo-first order rate constant k determined from high-performance liquid chromatography. The degradation of four different nitro-phenolic compounds was systematically studied using selected AOPs; these four compounds were nitrophenol, dinitrophenol, trinitrophenol and trinitroresorcin. It was observed that the combination of ultraviolet light with hydrogen peroxide H2O2 enhanced and maintained hydroxyl radicals, and therefore increased the conversion yield of organic pollutants. These AOPs provided efficient and green removal of stable organic toxins found in a wide range of industrial wastewater.

  2. Giardia duodenalis: Number and Fluorescence Reduction Caused by the Advanced Oxidation Process (H2O2/UV).

    PubMed

    Guimarães, José Roberto; Franco, Regina Maura Bueno; Guadagnini, Regiane Aparecida; Dos Santos, Luciana Urbano

    2014-01-01

    This study evaluated the effect of peroxidation assisted by ultraviolet radiation (H2O2/UV), which is an advanced oxidation process (AOP), on Giardia duodenalis cysts. The cysts were inoculated in synthetic and surface water using a concentration of 12 g H2O2 L(-1) and a UV dose (λ = 254 nm) of 5,480 mJcm(-2). The aqueous solutions were concentrated using membrane filtration, and the organisms were observed using a direct immunofluorescence assay (IFA). The AOP was effective in reducing the number of G. duodenalis cysts in synthetic and surface water and was most effective in reducing the fluorescence of the cyst walls that were present in the surface water. The AOP showed a higher deleterious potential for G. duodenalis cysts than either peroxidation (H2O2) or photolysis (UV) processes alone.

  3. Reduction of organic trace compounds and fresh water consumption by recovery of advanced oxidation processes treated industrial wastewater.

    PubMed

    Bierbaum, S; Öller, H-J; Kersten, A; Klemenčič, A Krivograd

    2014-01-01

    Ozone (O(3)) has been used successfully in advanced wastewater treatment in paper mills, other sectors and municipalities. To solve the water problems of regions lacking fresh water, wastewater treated by advanced oxidation processes (AOPs) can substitute fresh water in highly water-consuming industries. Results of this study have shown that paper strength properties are not impaired and whiteness is slightly impaired only when reusing paper mill wastewater. Furthermore, organic trace compounds are becoming an issue in the German paper industry. The results of this study have shown that AOPs are capable of improving wastewater quality by reducing organic load, colour and organic trace compounds.

  4. Measurement of hydrogen peroxide in an advanced oxidation process using an automated biosensor.

    PubMed

    Modrzejewska, B; Guwy, A J; Dinsdale, R; Hawkes, D L

    2007-01-01

    A hydrogen peroxide biosensor was used to monitor hydrogen peroxide concentrations in a UV/hydrogen peroxide immobilised Fenton advanced oxidation process (AOP). The biosensor is based on gas phase monitoring and thus is more resistant to fouling from the liquid phase constituents of industrial processes. The biosensor is supplied with catalase continually, therefore overcoming any problems with enzyme degradation, which would occur in an immobilised enzyme biosensor. The biosensors response was linear within the experimental range 30-400mg H(2)O(2)l(-1) with a R(2) correlation of 0.99. The hydrogen peroxide monitor was used to monitor residual peroxide in an AOP, operated with a step overload of hydrogen peroxide, with correlation factors of 0.96-0.99 compared to offline hydrogen peroxide determinations by UV spectroscopy. Sparging the sample with nitrogen was found to be effective in reducing the interference from dissolved gases produced with the AOP itself. It is proposed that this biosensor could be used to improve the effectiveness of AOPs via hydrogen peroxide control.

  5. Formation of disinfection by-products in the ultraviolet/chlorine advanced oxidation process.

    PubMed

    Wang, Ding; Bolton, James R; Andrews, Susan A; Hofmann, Ron

    2015-06-15

    Disinfection by-product (DBP) formation may be a concern when applying ultraviolet light and free chlorine (UV/chlorine) as an advanced oxidation process (AOP) for drinking water treatment, due to typically large chlorine doses (e.g. 5-10 mg L(-1) as free chlorine). A potential mitigating factor is the low chlorine contact times for this AOP treatment (e.g. seconds). Full-scale and pilot-scale test results showed minimal trihalomethane (THM) and haloacetic acid (HAA) formation during UV/chlorine treatment, while dichloroacetonitrile (DCAN) and bromochloroacetonitrile (BCAN) were produced rapidly. Adsorbable organic halide (AOX) formation was significant when applying the UV/chlorine process in water that had not been previously chlorinated, while little additional formation was observed in prechlorinated water. Chlorine photolysis led to chlorate and bromate formation, equivalent to approximately 2-17% and 0.01-0.05% of the photolyzed chlorine, respectively. No perchlorate or chlorite formation was observed. During simulated secondary disinfection of AOP-treated water, DBP formation potential for THMs, HAAs, HANs, and AOX was observed to increase approximately to the same extent as was observed for pretreatment using the more common AOP of UV combined with hydrogen peroxide (UV/H2O2).

  6. Treatment of dairy manure using the microwave enhanced advanced oxidation process under a continuous mode operation.

    PubMed

    Yu, Yang; Lo, Ing W; Liao, Ping H; Lo, Kwang V

    2010-11-01

    The microwave enhanced advanced oxidation process (MW/H(2)O(2)-AOP) was used to treat dairy manure for solubilization of nutrients and organic matters. This study investigated the effectiveness of the MW/H(2)O(2)-AOP under a continuous mode of operation, and compared the results to those of batch operations. The main factors affecting solubilization by the MW/H(2)O(2)-AOP were heating temperature and hydrogen peroxide dosage. Soluble chemical oxygen demand (SCOD) and volatile fatty acids (VFA) increased with an increase of microwave (MW) heating temperature; very high concentrations were obtained at 90°C. Insignificant amounts of ammonia and reducing sugars were released in all runs. An acidic pH condition was required for phosphorus solubilisation from dairy manure. The best yield was obtained at 90°C with an acid dosage of 1.0 %; about 92 % of total phosphorus and 90 % of total chemical oxygen demand were in the soluble forms. The MW/H(2)O(2)-AOP operated in a continuous operation mode showed pronounced synergistic effects between hydrogen peroxide and microwave irradiation when compared to a batch system under similar operating conditions, resulting in much better yields.

  7. Removal of disinfection by-product precursors with ozone-UV advanced oxidation process.

    PubMed

    Chin, A; Bérubé, P R

    2005-05-01

    The efficacy of using ozone (O3), ultraviolet irradiation (UV) and the combined O3-UV advanced oxidation process (AOP) to remove 2 classes of disinfection by-product (DBP) precursors from raw surface water samples have been evaluated and compared. In particular, trihalomethane and haloacetic acids formation potentials were measured. Laboratory batch scale experiments were carried out as a function of ozone and UV dosage in order to study the removal kinetics. It is concluded that the combined O3-UV AOP is more effective than either the ozone or UV treatment alone. Ozone-UV AOP is capable of mineralizing up to 50% of the total organic carbon from the raw source water at an ozone dose of 0.62+/-0.019 mg O3/mL and a UV dose of 1.61 W s/cm2. In addition, O3-UV AOP can reduce trihalomethane formation potential by roughly 80% and haloacetic acids formation potential by roughly 70% at the same ozone and UV dosage.

  8. RELATIVE REACTIVITY OF CONTAMINANT CANDIDATE LIST PESTICIDES TO OH RADICAL OXIDATION

    EPA Science Inventory

    Advanced oxidation processes (AOPs) represent those technologies that bring about enhanced oxidative degradation of pollutants in aqueous solution by the generation of hydroxyl radical (•OH). US Environmental Protection Agency (EPA) published, in February 2005, the second Contam...

  9. RELATIVE REACTIVITY OF CONTAMINANT CANDIDATE LIST PESTICIDES TO OH RADICAL OXIDATION ABSTRACT

    EPA Science Inventory

    Advanced oxidation processes (AOPs) represent those technologies that bring about enhanced oxidative degradation of pollutants in aqueous solution by the generation of hydroxyl radical (•OH). US Environmental Protection Agency (EPA) published, in February 2005, the second Contami...

  10. Three genes encoding AOP2, a protein involved in aliphatic glucosinolate biosynthesis, are differentially expressed in Brassica rapa.

    PubMed

    Zhang, Jifang; Liu, Zhiyuan; Liang, Jianli; Wu, Jian; Cheng, Feng; Wang, Xiaowu

    2015-10-01

    The glucosinolate biosynthetic gene AOP2 encodes an enzyme that plays a crucial role in catalysing the conversion of beneficial glucosinolates into anti-nutritional ones. In Brassica rapa, three copies of BrAOP2 have been identified, but their function in establishing the glucosinolate content of B. rapa is poorly understood. Here, we used phylogenetic and gene structure analyses to show that BrAOP2 proteins have evolved via a duplication process retaining two highly conserved domains at the N-terminal and C-terminal regions, while the middle part has experienced structural divergence. Heterologous expression and in vitro enzyme assays and Arabidopsis mutant complementation studies showed that all three BrAOP2 genes encode functional BrAOP2 proteins that convert the precursor methylsulfinyl alkyl glucosinolate to the alkenyl form. Site-directed mutagenesis showed that His356, Asp310, and Arg376 residues are required for the catalytic activity of one of the BrAOP2 proteins (BrAOP2.1). Promoter-β-glucuronidase lines revealed that the BrAOP2.3 gene displayed an overlapping but distinct tissue- and cell-specific expression profile compared with that of the BrAOP2.1 and BrAOP2.2 genes. Quantitative real-time reverse transcription-PCR assays demonstrated that BrAOP2.1 showed a slightly different pattern of expression in below-ground tissue at the seedling stage and in the silique at the reproductive stage compared with BrAOP2.2 and BrAOP2.3 genes in B. rapa. Taken together, our results revealed that all three BrAOP2 paralogues are active in B. rapa but have functionally diverged.

  11. Degradation of triketone herbicides, mesotrione and sulcotrione, using advanced oxidation processes.

    PubMed

    Jović, Milica; Manojlović, Dragan; Stanković, Dalibor; Dojčinović, Biljana; Obradović, Bratislav; Gašić, Uroš; Roglić, Goran

    2013-09-15

    Degradation of two triketone herbicides, mesotrione and sulcotrione, was studied using four different advanced oxidation processes (AOPs): ozonization, dielectric barrier discharge (DBD reactor), photocatalysis and Fenton reagent, in order to find differences in mechanism of degradation. Degradation products were identified by high performance liquid chromatography (HPLC-DAD) and UHPLC-Orbitrap-MS analyses. A simple mechanism of degradation for different AOP was proposed. Thirteen products were identified during all degradations for both pesticides. It was assumed that the oxidation mechanisms in the all four technologies were not based only on the production and use of the hydroxyl radical, but they also included other kinds of oxidation mechanisms specific for each technology. Similarity was observed between degradation mechanism of ozonation and DBD. The greatest difference in the products was found in Fenton degradation which included the opening of benzene ring. When degraded with same AOP pesticides gave at the end of treatment the same products. Global toxicity and COD value of samples was determined after all degradations. Real water sample was used to study influence of organic matter on pesticide degradation. These results could lead to accurate estimates of the overall effects of triketone herbicides on environmental ecosystems and also contributed to the development of improved removal processes.

  12. Impact of hydrodynamics on pollutant degradation and energy efficiency of VUV/UV and H2O2/UV oxidation processes.

    PubMed

    Bagheri, Mehdi; Mohseni, Madjid

    2015-12-01

    The Vacuum-UV/UV process, an incipient catalyst/chemical-free advanced oxidation process (AOP), is potentially a cost-effective solution for the removal of harmful micropollutants from water. Utilizing a novel mechanistic numerical model, this work aimed to establish a thorough understanding of the degradation mechanisms in the VUV/UV process operating under continuous flow conditions, when compared with the widely applied H2O2/UV AOP. Of particular interest was the examination of the impact of flow characteristics (hydrodynamics) on the degradation efficacy of a target micropollutant during the VUV/UV and H2O2/UV AOPs. While hydroxyl radical (OH) oxidation was the dominant degradation pathway in both processes, the degradation efficacy of the VUV/UV process showed much stronger correlation with the extent of mixing in the photoreactor. Under a uniform flow regime, the degradation efficiency of the target pollutant achieved by the H2O2/UV process with 2- and 5 ppm H2O2 was greater than that provided by the VUV/UV process. Nonetheless, introduction of mixing and circulation zones to the VUV/UV reactor resulted in superior performance compared with the H2O2/UV AOP. Based on the electrical energy-per-order (EEO) analysis, incorporation of circulation zones resulted in a reduction of up to 50% in the overall energy cost of the VUV/UV AOP, while the corresponding reduction for the 5-ppm H2O2/UV system was less than 5%. Furthermore, the extent of OH scavenging of natural organic matter (NOM) on energy efficiency of the VUV/UV and H2O2/UV AOPs under continuous flow conditions was assessed using the EEO analysis.

  13. Solar-Enhanced Advanced Oxidation Processes for Water Treatment: Simultaneous Removal of Pathogens and Chemical Pollutants.

    PubMed

    Tsydenova, Oyuna; Batoev, Valeriy; Batoeva, Agniya

    2015-08-14

    The review explores the feasibility of simultaneous removal of pathogens and chemical pollutants by solar-enhanced advanced oxidation processes (AOPs). The AOPs are based on in-situ generation of reactive oxygen species (ROS), most notably hydroxyl radicals •OH, that are capable of destroying both pollutant molecules and pathogen cells. The review presents evidence of simultaneous removal of pathogens and chemical pollutants by photocatalytic processes, namely TiO2 photocatalysis and photo-Fenton. Complex water matrices with high loads of pathogens and chemical pollutants negatively affect the efficiency of disinfection and pollutant removal. This is due to competition between chemical substances and pathogens for generated ROS. Other possible negative effects include light screening, competitive photon absorption, adsorption on the catalyst surface (thereby inhibiting its photocatalytic activity), etc. Besides, some matrix components may serve as nutrients for pathogens, thus hindering the disinfection process. Each type of water/wastewater would require a tailor-made approach and the variables that were shown to influence the processes-catalyst/oxidant concentrations, incident radiation flux, and pH-need to be adjusted in order to achieve the required degree of pollutant and pathogen removal. Overall, the solar-enhanced AOPs hold promise as an environmentally-friendly way to substitute or supplement conventional water/wastewater treatment, particularly in areas without access to centralized drinking water or sewage/wastewater treatment facilities.

  14. Kinetics and pathways of ibuprofen degradation by the UV/chlorine advanced oxidation process.

    PubMed

    Xiang, Yingying; Fang, Jingyun; Shang, Chii

    2016-03-01

    The UV/chlorine advanced oxidation process (AOP), which forms reactive species such as hydroxyl radicals (HO) and reactive chlorine species (RCS) such as chlorine atoms (Cl) and Cl2(-), is being considered as an alternative to the UV/H2O2 AOP for the degradation of emerging contaminants. This study investigated the kinetics and pathways of the degradation of a recalcitrant pharmaceutical and personal care product (PPCP)-ibuprofen (IBP)-by the UV/chlorine AOP. The degradation of IBP followed the pseudo first-order kinetics. The first-order rate constant was 3.3 times higher in the UV/chlorine AOP than in the UV/H2O2 AOP for a given chemical molar dosage at pH 6. The first-order rate constant decreased from 3.1 × 10(-3) s(-1) to 5.5 × 10(-4) s(-1) with increasing pH from 6 to 9. Both HO and RCS contributed to the degradation, and the contribution of RCS increased from 22% to 30% with increasing pH from 6 to 9. The degradation was initiated by HO-induced hydroxylation and Cl-induced chlorine substitution, and sustained through decarboxylation, demethylation, chlorination and ring cleavage to form more stable products. Significant amounts of chlorinated intermediates/byproducts were formed from the UV/chlorine AOP, and four chlorinated products were newly identified. The yield of total organic chlorine (TOCl) was 31.6 μM after 90% degradation of 50 μM IBP under the experimental conditions. The known disinfection by-products (DBPs) comprised 17.4% of the TOCl. The effects of water matrix in filtered drinking water on the degradation were not significant, demonstrating the practicality of the UV/chlorine AOP for the control of some refractory PPCPs. However, the toxicity of the chlorinated products should be further assessed.

  15. Solar-Enhanced Advanced Oxidation Processes for Water Treatment: Simultaneous Removal of Pathogens and Chemical Pollutants

    PubMed Central

    Tsydenova, Oyuna; Batoev, Valeriy; Batoeva, Agniya

    2015-01-01

    The review explores the feasibility of simultaneous removal of pathogens and chemical pollutants by solar-enhanced advanced oxidation processes (AOPs). The AOPs are based on in-situ generation of reactive oxygen species (ROS), most notably hydroxyl radicals •OH, that are capable of destroying both pollutant molecules and pathogen cells. The review presents evidence of simultaneous removal of pathogens and chemical pollutants by photocatalytic processes, namely TiO2 photocatalysis and photo-Fenton. Complex water matrices with high loads of pathogens and chemical pollutants negatively affect the efficiency of disinfection and pollutant removal. This is due to competition between chemical substances and pathogens for generated ROS. Other possible negative effects include light screening, competitive photon absorption, adsorption on the catalyst surface (thereby inhibiting its photocatalytic activity), etc. Besides, some matrix components may serve as nutrients for pathogens, thus hindering the disinfection process. Each type of water/wastewater would require a tailor-made approach and the variables that were shown to influence the processes—catalyst/oxidant concentrations, incident radiation flux, and pH—need to be adjusted in order to achieve the required degree of pollutant and pathogen removal. Overall, the solar-enhanced AOPs hold promise as an environmentally-friendly way to substitute or supplement conventional water/wastewater treatment, particularly in areas without access to centralized drinking water or sewage/wastewater treatment facilities. PMID:26287222

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

    PubMed

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

    2015-06-16

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

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

    PubMed Central

    2015-01-01

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

  18. The effect of advanced oxidation processes on leachate biodegradation in recycling lysimeters.

    PubMed

    Ledakowicz, Stanisław; Kaczorek, Katarzyna

    2004-06-01

    Landfill processes were simulated in laboratory-scale bioreactors--lysimeters. The changes in leachate characteristics as well as the influence of advanced oxidation processes (AOPs) on the processes taking place in the sanitary landfill were investigated. Lysimeters were filled with material simulating municipal waste in the city of Lodz, Poland. Compost in the amount of 30% w/w and the methanogens inoculum were added in order to enhance development of a methanogenic phase. The leachate produced in lysimeters was recirculated. In order to investigate the influence of AOPs implementation on processes taking place in landfills two runs in lysimeters were performed, each lasting about 250 days. The leachate composition and biogas composition and production changes showed trends that confirmed that the bench-scale lysimeters appeared suitable to simulate processes taking place in the landfill. The application of AOPs to the leachate recirculated into the lysimeters did not bring about unequivocally positive effects. The ozonation of the leachate, implemented at the beginning of the methanogenic phase, caused slight acceleration (about 2 weeks) of the biodegradation, whereas employment of H2O2/UV led to the inhibition of anaerobic processes.

  19. Advanced oxidation processes for wastewater treatment using a plasma/ozone combination system

    NASA Astrophysics Data System (ADS)

    Takeuchi, Nozomi; Kamiya, Yu; Saeki, Ryo; Tachibana, Kosuke; Yasuoka, Koichi

    2014-10-01

    Advanced oxidation process (AOP) using OH radicals is a promising method for the decomposition of persistent organic compounds in wastewater. Although many types of plasma reactors have been developed for the AOP, they are unsuitable for the complete decomposition of highly concentrated organic compounds. The reason for the incomplete decomposition is that OH radicals, particularly at a high density, recombine among themselves to form hydrogen peroxide. We have developed a combination plasma reactor in which ozone gas is fed, so that the generated hydrogen peroxide is re-converted to OH radicals. Pulsed plasmas generated within oxygen bubbles supply not only OH radicals but also hydrogen peroxide into wastewater. The total organic carbon (TOC) of the wastewater was more than 1 gTOC/L. The TOC values decreased linearly with time, and the persistent compounds which could not be decomposed by ozone were completely mineralized within 8 h of operation.

  20. Understanding AOP through the Study of Interpreters

    NASA Technical Reports Server (NTRS)

    Filman, Robert E.

    2004-01-01

    I return to the question of what distinguishes AOP languages by considering how the interpreters of AOP languages differ from conventional interpreters. Key elements for static transformation are seen to be redefinition of the set and lookup operators in the interpretation of the language. This analysis also yields a definition of crosscutting in terms of interlacing of interpreter actions.

  1. Framework for computationally-predicted AOPs

    EPA Science Inventory

    Framework for computationally-predicted AOPs Given that there are a vast number of existing and new chemicals in the commercial pipeline, emphasis is placed on developing high throughput screening (HTS) methods for hazard prediction. Adverse Outcome Pathways (AOPs) represent a...

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

    PubMed

    Arslan-Alaton, Idil; Dogruel, Serdar

    2004-08-09

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

  3. UV-H2O2 based AOP and its integration with biological activated carbon treatment for DBP reduction in drinking water.

    PubMed

    Toor, Ramn; Mohseni, Madjid

    2007-02-01

    The presence of disinfection byproducts (DBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs) in drinking water is of great concern due to their adverse effects on human health. Emerging regulation limiting the concentration of DBPs in drinking water has increased demands for technologies and processes which reduce the formation of DBPs in drinking water. In this study, UV-H2O2 based advance oxidation process (AOP) was used to treat raw surface water. Experiments were conducted using low pressure mercury vapor UV lamps in collimated beam and flow-through annular photoreactors. The effect of UV fluence (0-3500 mJ cm(-2)) and hydrogen peroxide concentration (0-23 mg l(-1)) in reducing the concentration of THMs and HAAs was examined. The UV-H2O2 AOP was then coupled with a downstream biological activated carbon (BAC) treatment to assess the synergetic benefits of combining the two treatments. It was observed that UV-H2O2 AOP was only effective at reducing DBPs at UV fluences of more than 1000 mJ cm(-2) and initial H2O2 concentrations of about or greater than 23 mg l(-1). However, the combined AOP-BAC treatment showed significant reductions of 43%, 52%, and 59% relative to untreated raw water for DBPs, TOC, and UV254, respectively.

  4. NEPTUNIUM OXIDE PROCESSING

    SciTech Connect

    Jordan, J; Watkins, R; Hensel, S

    2009-05-27

    The Savannah River Site's HB-Line Facility completed a campaign in which fifty nine cans of neptunium oxide were produced and shipped to the Idaho National Laboratory in the 9975 shipping container. The neptunium campaign was divided into two parts: Part 1 which consisted of oxide made from H-Canyon neptunium solution which did not require any processing prior to conversion into an oxide, and Part 2 which consisted of oxide made from additional H-Canyon neptunium solutions which required processing to purify the solution prior to conversion into an oxide. The neptunium was received as a nitrate solution and converted to oxide through ion-exchange column extraction, precipitation, and calcination. Numerous processing challenges were encountered in order make a final neptunium oxide product that could be shipped in a 9975 shipping container. Among the challenges overcome was the issue of scale: translating lab scale production into full facility production. The balance between processing efficiency and product quality assurance was addressed during this campaign. Lessons learned from these challenges are applicable to other processing projects.

  5. Integrative data mining of high-throughput in vitro screens, in vivo data, and disease information to identify Adverse Outcome Pathway (AOP) signatures:ToxCast high-throughput screening data and Comparative Toxicogenomics Database (CTD) as a case study.

    EPA Science Inventory

    The Adverse Outcome Pathway (AOP) framework provides a systematic way to describe linkages between molecular and cellular processes and organism or population level effects. The current AOP assembly methods however, are inefficient. Our goal is to generate computationally-pr...

  6. Removing Fats, Oils and Greases from Grease Trap by Hybrid AOPs (Ozonation and Sonication)

    NASA Astrophysics Data System (ADS)

    Kwiatkowski, Michal Piotr; Satoh, Saburoh; Yamabe, Chobei; Ihara, Satoshi; Nieda, Masanori

    The purpose of this study was to investigate the electrical energy for the environmental applications using AOPs (advanced oxidation processes) combined with ozonation and sonication to remove the FOG (fats, oils and greases) from wastewater of the sewage system. This study focused on FOG removal from a grease trap using the hybrid AOPs. Fatty acids (linoleic, oleic, stearic and palmitic acids) were used as representative standards of FOG. The studies were conducted experimentally in a glass reactor under various operational conditions. The oxidation efficiency using the combination of the ozonation and sonication was determined by the KI dosimetry method and the calorimetry method. Fatty acids concentration were measured by GC/MS. The local reaction field of the high temperature and high pressure, so-called hot spot, was generated by the quasi-adiabatic collapse of bubbles produced in the water under sonication, which is called cavitation phenomenon. Mixing the ozone bubbles into the water under acoustic cavitation, the formation of OH radicals increased. The mechanical effect of acoustic cavitation such as microstreaming and shock waves have an influence on the probability of reactions of ozone and radicals with fatty acids.

  7. The degradation of dissolved organic nitrogen associated with melanoidin using a UV/H2O2 AOP.

    PubMed

    Dwyer, Jason; Kavanagh, Lydia; Lant, Paul

    2008-04-01

    The aim of this study was to examine the simultaneous degradation of dissolved organic nitrogen (DON) and associated colour from wastewater containing melanoidins by an advanced oxidation process (AOP). UV irradiation of H2O2 was used as the mechanism to create the hydroxyl radical for oxidation. Melanoidins are large nitrogenous organic compounds that are refractory during biological wastewater treatment processes. The simultaneous degradation of DON and colour, present as a result of these compounds, was investigated using an AOP. The oxidation process was much more capable of removing colour (99% degradation), dissolved organic carbon (DOC) (50% degradation) and DON (25% degradation) at the optimal applied dose of hydrogen peroxide for the system (3300 mg l(-1)). This indicated that colour and DON removal were decoupled problems for the purpose of treating melanoidin by an AOP and thus colour removal can not be used as an indication of DON removal Colour was caused by organic molecules with molecular weight greater than 10 kDa. Oxidation caused a partial reduction of the DON (41-15% of the total dissolved nitrogen) and DOC (29-14% of the DOC) associated with the large molecular weight fraction (>10 kDa) and almost complete colour removal (87-3% of the total colour). The degraded DON was mostly accounted for by the formation of ammonia (31% of the nitrogen removed from the large fraction) and small molecular weight compounds (66% of the nitrogen removed from the large fraction). The degraded DOC appeared to be mostly mineralised (to CO2) with only 20% of the degraded compounds appearing as small molecular weight DOC.

  8. AOPs and Biomarkers: Bridging High Throughput Screening ...

    EPA Pesticide Factsheets

    As high throughput screening (HTS) plays a larger role in toxicity testing, camputational toxicology has emerged as a critical component in interpreting the large volume of data produced. Computational models designed to quantify potential adverse effects based on HTS data will benefit from additional data sources that connect the magnitude of perturbation from the in vitro system to a level of concern at the organism or population level. The adverse outcome pathway (AOP) concept provides an ideal framework for combining these complementary data. Recent international efforts under the auspices of the Organization for Economic Co-operation and Development (OECD) have resulted in an AOP wiki designed to house formal descriptions of AOPs suitable for use in regulatory decision making. Recent efforts have built upon this to include an ontology describing the AOP with linkages to biological pathways, physiological terminology, and taxonomic applicability domains. Incorporation of an AOP network tool developed by the U.S. Army Corps of Engineers also allows consideration of cumulative risk from chemical and non-chemical stressors. Biomarkers are an important complement to formal AOP descriptions, particularly when dealing with susceptible subpopulations or lifestages in human health risk assessment. To address the issue of nonchemical stressors than may modify effects of criteria air pollutants, a novel method was used to integrate blood gene expression data with hema

  9. ADVANCED OXIDATION PROCESS

    SciTech Connect

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

    2003-11-04

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

  10. [Effects of organic pollutants in drinking water on the removal of dimethyl phthalate by advanced oxidation processes].

    PubMed

    Rui, Min; Gao, Nai-yun; Xu, Bin; Li, Fu-sheng; Zhao, Jian-fu; Le, Lin-sheng

    2006-12-01

    Humic acids were used to simulate natural organic compounds in water for the investigation of DMP oxidation by three different AOPs (advanced oxidation processes) of UV-H2O2, O3 and UV-O3. The results showed that pseudo-first-order reaction equation could describe the oxidation of DMP by UV-H2O2 perfectly, which was strongly affected humic acids in water. The relationship between pseudo-first-order reaction rate and TOC value could be expressed as K = 0. 162 0 [TOC]-0.8171. It was also found that humic acids in the water exhibited obvious influence on the oxidation of DMP by UV-O3. However, effect of humic acids on the oxidation of DMP by ozone was not obvious. It was also analyzed that oxidation of DMP was dominated by ozone oxidation both in ozonation process and UV-O3 process; the importance of "OH in the oxidation of DMP was enhanced as the concentration of DMP decreased in UV-O3 process. The degree of impact form humic acids towards different AOPs could be ranked in a decreasing order as UV-H2O3, UV-O3, 03.

  11. Surface XPS characterization of NiTi shape memory alloy after advanced oxidation processes in UV/H 2O 2 photocatalytic system

    NASA Astrophysics Data System (ADS)

    Wang, R. M.; Chu, C. L.; Hu, T.; Dong, Y. S.; Guo, C.; Sheng, X. B.; Lin, P. H.; Chung, C. Y.; Chu, P. K.

    2007-08-01

    Surface structure of NiTi shape memory alloy (SMA) was modified by advanced oxidation processes (AOP) in an ultraviolet (UV)/H 2O 2 photocatalytic system, and then systematically characterized with x-ray photoelectron spectroscopy (XPS). It is found that the AOP in UV/H 2O 2 photocatalytic system leads to formation of titanium oxides film on NiTi substrate. Depth profiles of O, Ni and Ti show such a film possesses a graded interface structure to NiTi substrate and there is no intermediate Ni-rich layer like that produced in conventional high temperature oxidation. Except TiO 2 phase, some titanium suboxides (TiO, Ti 2O 3) may also exist in the titanium oxides film. Oxygen mainly presents in metal oxides and some chemisorbed water and OH - are found in titanium oxides film. Ni nearly reaches zero on the upper surface and relatively depleted in the whole titanium oxides film. The work indicates the AOP in UV/H 2O 2 photocatalytic system is a promising way to favor the widespread application of biomedical NiTi SMA by improving its biocompatibility.

  12. Micropollutant degradation, bacterial inactivation and regrowth risk in wastewater effluents: Influence of the secondary (pre)treatment on the efficiency of Advanced Oxidation Processes.

    PubMed

    Giannakis, Stefanos; Voumard, Margaux; Grandjean, Dominique; Magnet, Anoys; De Alencastro, Luiz Felippe; Pulgarin, César

    2016-10-01

    In this work, disinfection by 5 Advanced Oxidation Processes was preceded by 3 different secondary treatment systems present in the wastewater treatment plant of Vidy, Lausanne (Switzerland). 5 AOPs after two biological treatment methods (conventional activated sludge and moving bed bioreactor) and a physiochemical process (coagulation-flocculation) were tested in laboratory scale. The dependence among AOPs efficiency and secondary (pre)treatment was estimated by following the bacterial concentration i) before secondary treatment, ii) after the different secondary treatment methods and iii) after the various AOPs. Disinfection and post-treatment bacterial regrowth were the evaluation indicators. The order of efficiency was Moving Bed Bioreactor > Activated Sludge > Coagulation-Flocculation > Primary Treatment. As far as the different AOPs are concerned, the disinfection kinetics were: UVC/H2O2 > UVC and solar photo-Fenton > Fenton or solar light. The contextualization and parallel study of microorganisms with the micropollutants of the effluents revealed that higher exposure times were necessary for complete degradation compared to microorganisms for the UV-based processes and inversed for the Fenton-related ones. Nevertheless, in the Fenton-related systems, the nominal 80% removal of micropollutants deriving from the Swiss legislation, often took place before the elimination of bacterial regrowth risk.

  13. Review of fundamentals and specific aspects of oxidation technologies in marine waters.

    PubMed

    Kornmueller, A

    2007-01-01

    This review is based on the existing literature and on our experiences in the application of different oxidation processes in brackish water and seawater. The oxidation reactions of advanced oxidation processes (AOPs) and the formation of disinfection byproducts (DBPs) are considerably different in marine waters from well-known drinking, process and wastewater applications. In contrast, the major secondary oxidants are bromine species in marine waters, which might form the DBPs of concern bromate and bromoform. An efficient AOP application needs knowledge of the source water constitutions and the oxidant demand. Besides changes in the oxidants chemistry compared to fresh water, the great and seasonal variation of marine waters has to be considered in the process design. The complexity of oxidant reactions and formation of byproducts are only partially researched and known as yet. Hence, it is advisable to determine the characteristic and variation of the water source as well as its influence on each AOP in experiments prior to the process design.

  14. Adverse outcome pathway (AOP) development and evaluation ...

    EPA Pesticide Factsheets

    The Adverse Outcome Pathway provides a construct for assembling mechanistic information at different levels of biological organization in a form designed to support regulatory decision making. In particular, it frames the link between molecular and cellular events that can be measured in high throughput toxicity testing and the organism or population-level events that are commonly relevant in defining risk. Recognizing the importance of this emerging framework, the Organisation for Economic Co-operation and Development (OECD) launched a program to support the development, documentation and consideration of AOPs by the international community in 2012 (http://www.oecd.org/chemicalsafety/testing/adverse-outcome-pathways-molecular-screening-and-toxicogenomics.htm). In 2014, a handbook (https://aopkb.org/common/AOP_Handbook.pdf) was developed to guide users in the documentation and evaluation of AOPs and their entry into an official knowledgebase. The handbook draws on longstanding experience in consideration of mechanistic data (e.g., mode of action analysis) to inform risk assessment. To further assist users, a training program was developed by members of the OECD Extended Advisory Group to teach users the basic principles of AOP development and the best practices as outlined in the OECD AOP handbook. Training sessions began in early 2015, and this course will provide training for interested SOT scientists. Following this course, all participants will be familiar w

  15. Quantitative analysis of trace chromium in blood samples. Combination of the advanced oxidation process with catalytic adsorptive stripping voltammetry.

    PubMed

    Yong, Li; Armstrong, Kristie C; Dansby-Sparks, Royce N; Carrington, Nathan A; Chambers, James Q; Xue, Zi-Ling

    2006-11-01

    A new method for pretreating blood samples for trace Cr analysis is described. The advanced oxidation process (AOP with H2O2 and 5.5-W UV irradiation for 60 min) is used to remove biological/organic species for subsequent analysis. Prior to the AOP pretreatment, acid (HNO3) is used at pH 3.0 to inhibit the enzyme catalase in the blood samples. Catalytic adsorptive stripping voltammetry at a bismuth film electrode gives a Cr concentration of 6.0 +/- 0.3 ppb in the blood samples. This concentration was confirmed by dry-ashing the blood samples and subsequent analysis by atomic absorption spectroscopy. This current method may be used to monitor chromium, a trace metal in humans, and the efficacy and safety of chromium supplements as adjuvant therapy for diabetes.

  16. Sulfur oxides scrubbing process

    SciTech Connect

    Reeder, P.E.

    1986-07-15

    A process is described for removing sulfur oxides and solid particulates from a gaseous effluent. The steps of the process consist of: contacting within a venturi structure a gaseous effluent containing sulfur oxides with a liquid scrubbing mixture; passing the admixture of the gaseous effluent and liquid scrubbing mixture through a constricted passage of the venturi structure to increase the velocity thereof; separating the admixture into a liquid portion and a gas portion; delivering the gas portion of the separation step to a packed tower beneath the packed section thereof; contacting the gas portion with liquid scrubbing mixture in the packed section of the tower to form a gaseous overhead effluent substantially free of sulfur oxides and a bottoms liquid; combining the bottom liquid from the packed section of the tower with the liquid portion from the separating step to form a combined liquid bottoms; adjusting the pH of the combined liquid bottoms with a basic solution to form a liquid scrubbing mixture, the basic solution selected from the group consisting of alkali metal hydroxides, ammonium hydroxide, and ammonia; and dividing the liquid scrubbing mixture into a tower bottoms products, a first recycle stream providing the liquid scrubbing mixture to the first contacting step, and a second recycle stream providing the liquid scrubbing mixture to the second contacting step.

  17. Evaluation of trihalomethane formation potential in function of oxidation processes used during the drinking water production process.

    PubMed

    Mosteo, R; Miguel, N; Martin-Muniesa, S; Ormad, Maria P; Ovelleiro, José L

    2009-12-30

    The presence of natural organic matter (NOM) in both surface and groundwater supplies produces toxic by-products, mainly trihalomethanes (THMs), during oxidation steps in drinking water production. This research work shows the efficiency of different advanced oxidation processes (AOPs) based on ozone for the degradation of precursors of trihalomethanes in aqueous solutions. Completed treatments comprised different preoxidation processes (chlorination and AOP: O(3), O(3)/H(2)O(2), O(3)/TiO(2) and O(3)/H(2)O(2)/TiO(2)), adsorption with PAC (optional operation), coagulation-flocculation and final postchlorination applied to synthetic samples which were prepared by dilution of the soluble fraction of a humic solution. A direct chlorination of synthetic humic samples which display dissolved organic carbon close to 3 mg l(-1) produced a THM concentration of around 1600 microg CCl(3)l(-1) (measured as THMFP). Comparisons between the trihalomethane formation potential of initial synthetic samples and samples treated by prechlorination and coagulation-flocculation-decantation show that the main factor responsible for THM reduction is the coagulation-flocculation process since a decrease of 90% is achieved. Considering the various completed treatments studied, the most recommendable include preoxidation by ozonation, adsorption by PAC, coagulation-flocculation using aluminium sulphate followed by decantation and final postchlorination.

  18. Catalytic process for formaldehyde oxidation

    NASA Technical Reports Server (NTRS)

    Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); D'Ambrosia, Christine M. (Inventor)

    1996-01-01

    Disclosed is a process for oxidizing formaldehyde to carbon dioxide and water without the addition of energy. A mixture of formaldehyde and an oxidizing agent (e.g., ambient air containing formaldehyde) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

  19. The chemistry side of AOP: implications for toxicity extrapolation

    EPA Science Inventory

    An adverse outcome pathway (AOP) is a structured representation of the biological events that lead to adverse impacts following a molecular initiating event caused by chemical interaction with a macromolecule. AOPs have been proposed to facilitate toxicity extrapolation across s...

  20. Adverse Outcome Pathway (AOP) Network Development for Fatty Liver

    EPA Science Inventory

    Adverse outcome pathways (AOPs) are descriptive biological sequences that start from a molecular initiating event (MIE) and end with an adverse health outcome. AOPs provide biological context for high throughput chemical testing and further prioritize environmental health risk re...

  1. Sequential ozone advanced oxidation and biological oxidation processes to remove selected pharmaceutical contaminants from an urban wastewater.

    PubMed

    Espejo, Azahara; Aguinaco, Almudena; García-Araya, J F; Beltrán, Fernando J

    2014-01-01

    Sequential treatments consisting in a chemical process followed by a conventional biological treatment, have been applied to remove mixtures of nine contaminants of pharmaceutical type spiked in a primary sedimentation effluent of a municipal wastewater. Combinations of ozone, UVA black light (BL) and Fe(III) or Fe₃O₄ catalysts constituted the chemical systems. Regardless of the Advanced Oxidation Process (AOP), the removal of pharmaceutical compounds was achieved in 1 h of reaction, while total organic carbon (TOC) only diminished between 3.4 and 6%. Among selected ozonation systems to be implemented before the biological treatment, the application of ozone alone in the pre-treatment stage is recommended due to the increase of the biodegradability observed. The application of ozone followed by the conventional biological treatment leads high TOC and COD removal rates, 60 and 61%, respectively, and allows the subsequent biological treatment works with shorter hydraulic residence time (HRT). Moreover, the influence of the application of AOPs before and after a conventional biological process was compared, concluding that the decision to take depends on the characterization of the initial wastewater with pharmaceutical compounds.

  2. Formation of brominated disinfection byproducts from natural organic matter isolates and model compounds in a sulfate radical-based oxidation process.

    PubMed

    Wang, Yuru; Le Roux, Julien; Zhang, Tao; Croué, Jean-Philippe

    2014-12-16

    A sulfate radical-based advanced oxidation process (SR-AOP) has received increasing application interest for the removal of water/wastewater contaminants. However, limited knowledge is available on its side effects. This study investigated the side effects in terms of the production of total organic bromine (TOBr) and brominated disinfection byproducts (Br-DBPs) in the presence of bromide ion and organic matter in water. Sulfate radical was generated by heterogeneous catalytic activation of peroxymonosulfate. Isolated natural organic matter (NOM) fractions as well as low molecular weight (LMW) compounds were used as model organic matter. Considerable amounts of TOBr were produced by SR-AOP, where bromoform (TBM) and dibromoacetic acid (DBAA) were identified as dominant Br-DBPs. In general, SR-AOP favored the formation of DBAA, which is quite distinct from bromination with HOBr/OBr(-) (more TBM production). SR-AOP experimental results indicate that bromine incorporation is distributed among both hydrophobic and hydrophilic NOM fractions. Studies on model precursors reveal that LMW acids are reactive TBM precursors (citric acid > succinic acid > pyruvic acid > maleic acid). High DBAA formation from citric acid, aspartic acid, and asparagine was observed; meanwhile aspartic acid and asparagine were the major precursors of dibromoacetonitrile and dibromoacetamide, respectively.

  3. Electrochemical advanced oxidation and biological processes for wastewater treatment: a review of the combined approaches.

    PubMed

    Ganzenko, Oleksandra; Huguenot, David; van Hullebusch, Eric D; Esposito, Giovanni; Oturan, Mehmet A

    2014-01-01

    As pollution becomes one of the biggest environmental challenges of the twenty-first century, pollution of water threatens the very existence of humanity, making immediate action a priority. The most persistent and hazardous pollutants come from industrial and agricultural activities; therefore, effective treatment of this wastewater prior to discharge into the natural environment is the solution. Advanced oxidation processes (AOPs) have caused increased interest due to their ability to degrade hazardous substances in contrast to other methods, which mainly only transfer pollution from wastewater to sludge, a membrane filter, or an adsorbent. Among a great variety of different AOPs, a group of electrochemical advanced oxidation processes (EAOPs), including electro-Fenton, is emerging as an environmental-friendly and effective treatment process for the destruction of persistent hazardous contaminants. The only concern that slows down a large-scale implementation is energy consumption and related investment and operational costs. A combination of EAOPs with biological treatment is an interesting solution. In such a synergetic way, removal efficiency is maximized, while minimizing operational costs. The goal of this review is to present cutting-edge research for treatment of three common and problematic pollutants and effluents: dyes and textile wastewater, olive processing wastewater, and pharmaceuticals and hospital wastewater. Each of these types is regarded in terms of recent scientific research on individual electrochemical, individual biological and a combined synergetic treatment.

  4. Reduction of antibiotic resistance genes in municipal wastewater effluent by advanced oxidation processes.

    PubMed

    Zhang, Yingying; Zhuang, Yao; Geng, Jinju; Ren, Hongqiang; Xu, Ke; Ding, Lili

    2016-04-15

    This study investigated the reduction of antibiotic resistance genes (ARGs), intI1 and 16S rRNA genes, by advanced oxidation processes (AOPs), namely Fenton oxidation (Fe(2+)/H2O2) and UV/H2O2 process. The ARGs include sul1, tetX, and tetG from municipal wastewater effluent. The results indicated that the Fenton oxidation and UV/H2O2 process could reduce selected ARGs effectively. Oxidation by the Fenton process was slightly better than that of the UV/H2O2 method. Particularly, for the Fenton oxidation, under the optimal condition wherein Fe(2+)/H2O2 had a molar ratio of 0.1 and a H2O2 concentration of 0.01molL(-1) with a pH of 3.0 and reaction time of 2h, 2.58-3.79 logs of target genes were removed. Under the initial effluent pH condition (pH=7.0), the removal was 2.26-3.35 logs. For the UV/H2O2 process, when the pH was 3.5 with a H2O2 concentration of 0.01molL(-1) accompanied by 30min of UV irradiation, all ARGs could achieve a reduction of 2.8-3.5 logs, and 1.55-2.32 logs at a pH of 7.0. The Fenton oxidation and UV/H2O2 process followed the first-order reaction kinetic model. The removal of target genes was affected by many parameters, including initial Fe(2+)/H2O2 molar ratios, H2O2 concentration, solution pH, and reaction time. Among these factors, reagent concentrations and pH values are the most important factors during AOPs.

  5. Accelerating Adverse Outcome Pathway (AOP) development via computationally predicted AOP networks

    EPA Science Inventory

    The Adverse Outcome Pathway (AOP) framework is increasingly being adopted as a tool for organizing and summarizing the mechanistic information connecting molecular perturbations by environmental stressors with adverse outcomes relevant for ecological and human health outcomes. Ho...

  6. Analytical tools employed to determine pharmaceutical compounds in wastewaters after application of advanced oxidation processes.

    PubMed

    Afonso-Olivares, Cristina; Montesdeoca-Esponda, Sarah; Sosa-Ferrera, Zoraida; Santana-Rodríguez, José Juan

    2016-12-01

    Today, the presence of contaminants in the environment is a topic of interest for society in general and for the scientific community in particular. A very large amount of different chemical substances reaches the environment after passing through wastewater treatment plants without being eliminated. This is due to the inefficiency of conventional removal processes and the lack of government regulations. The list of compounds entering treatment plants is gradually becoming longer and more varied because most of these compounds come from pharmaceuticals, hormones or personal care products, which are increasingly used by modern society. As a result of this increase in compound variety, to address these emerging pollutants, the development of new and more efficient removal technologies is needed. Different advanced oxidation processes (AOPs), especially photochemical AOPs, have been proposed as supplements to traditional treatments for the elimination of pollutants, showing significant advantages over the use of conventional methods alone. This work aims to review the analytical methodologies employed for the analysis of pharmaceutical compounds from wastewater in studies in which advanced oxidation processes are applied. Due to the low concentrations of these substances in wastewater, mass spectrometry detectors are usually chosen to meet the low detection limits and identification power required. Specifically, time-of-flight detectors are required to analyse the by-products.

  7. Degradation of estrone in water and wastewater by various advanced oxidation processes.

    PubMed

    Sarkar, Shubhajit; Ali, Sura; Rehmann, Lars; Nakhla, George; Ray, Madhumita B

    2014-08-15

    A comprehensive study was conducted to determine the relative efficacy of various advanced oxidation processes such as O3, H2O2, UV, and combinations of UV/O3, UV/H2O2 for the removal of estrone (E1) from pure water and secondary effluent. In addition to the parent compound (E1) removal, performance of the advanced oxidation processes was characterized using removal of total organic carbon (TOC), and estrogenicity of the effluent. Although E1 removal was high for all the AOPs, intermediates formed were more difficult to degrade leading to slow TOC removal. Energy calculations and cost analysis indicated that, although UV processes have low electricity cost, ozonation is the least cost option ($ 0.34/1000 gallons) when both capital and operating costs were taken into account. Ozonation also is superior to the other tested AOPs due to higher removal of TOC and estrogenicity. The rate of E1 removal decreased linearly with the background TOC in water, however, E1 degradation in the secondary effluent from a local wastewater treatment plant was not affected significantly due to the low COD values in the effluent.

  8. AOP Knowledge Base/Wiki Tool Set

    EPA Science Inventory

    Utilizing ToxCast Data and Lifestage Physiologically-Based Pharmacokinetic (PBPK) models to Drive Adverse Outcome Pathways (AOPs)-Based Margin of Exposures (ABME) to Chemicals. Hisham A. El-Masri1, Nicole C. Klienstreur2, Linda Adams1, Tamara Tal1, Stephanie Padilla1, Kristin Is...

  9. Adverse outcome pathway (AOP) development I: strategies and principles.

    PubMed

    Villeneuve, Daniel L; Crump, Doug; Garcia-Reyero, Natàlia; Hecker, Markus; Hutchinson, Thomas H; LaLone, Carlie A; Landesmann, Brigitte; Lettieri, Teresa; Munn, Sharon; Nepelska, Malgorzata; Ottinger, Mary Ann; Vergauwen, Lucia; Whelan, Maurice

    2014-12-01

    An adverse outcome pathway (AOP) is a conceptual framework that organizes existing knowledge concerning biologically plausible, and empirically supported, links between molecular-level perturbation of a biological system and an adverse outcome at a level of biological organization of regulatory relevance. Systematic organization of information into AOP frameworks has potential to improve regulatory decision-making through greater integration and more meaningful use of mechanistic data. However, for the scientific community to collectively develop a useful AOP knowledgebase that encompasses toxicological contexts of concern to human health and ecological risk assessment, it is critical that AOPs be developed in accordance with a consistent set of core principles. Based on the experiences and scientific discourse among a group of AOP practitioners, we propose a set of five fundamental principles that guide AOP development: (1) AOPs are not chemical specific; (2) AOPs are modular and composed of reusable components-notably key events (KEs) and key event relationships (KERs); (3) an individual AOP, composed of a single sequence of KEs and KERs, is a pragmatic unit of AOP development and evaluation; (4) networks composed of multiple AOPs that share common KEs and KERs are likely to be the functional unit of prediction for most real-world scenarios; and (5) AOPs are living documents that will evolve over time as new knowledge is generated. The goal of the present article was to introduce some strategies for AOP development and detail the rationale behind these 5 key principles. Consideration of these principles addresses many of the current uncertainties regarding the AOP framework and its application and is intended to foster greater consistency in AOP development.

  10. Adverse Outcome Pathway (AOP) Development I: Strategies and Principles

    PubMed Central

    Villeneuve, Daniel L.; Crump, Doug; Garcia-Reyero, Natàlia; Hecker, Markus; Hutchinson, Thomas H.; LaLone, Carlie A.; Landesmann, Brigitte; Lettieri, Teresa; Munn, Sharon; Nepelska, Malgorzata; Ottinger, Mary Ann; Vergauwen, Lucia; Whelan, Maurice

    2014-01-01

    An adverse outcome pathway (AOP) is a conceptual framework that organizes existing knowledge concerning biologically plausible, and empirically supported, links between molecular-level perturbation of a biological system and an adverse outcome at a level of biological organization of regulatory relevance. Systematic organization of information into AOP frameworks has potential to improve regulatory decision-making through greater integration and more meaningful use of mechanistic data. However, for the scientific community to collectively develop a useful AOP knowledgebase that encompasses toxicological contexts of concern to human health and ecological risk assessment, it is critical that AOPs be developed in accordance with a consistent set of core principles. Based on the experiences and scientific discourse among a group of AOP practitioners, we propose a set of five fundamental principles that guide AOP development: (1) AOPs are not chemical specific; (2) AOPs are modular and composed of reusable components—notably key events (KEs) and key event relationships (KERs); (3) an individual AOP, composed of a single sequence of KEs and KERs, is a pragmatic unit of AOP development and evaluation; (4) networks composed of multiple AOPs that share common KEs and KERs are likely to be the functional unit of prediction for most real-world scenarios; and (5) AOPs are living documents that will evolve over time as new knowledge is generated. The goal of the present article was to introduce some strategies for AOP development and detail the rationale behind these 5 key principles. Consideration of these principles addresses many of the current uncertainties regarding the AOP framework and its application and is intended to foster greater consistency in AOP development. PMID:25466378

  11. Microwaves and their coupling to advanced oxidation processes: enhanced performance in pollutants degradation.

    PubMed

    Nascimento, Ulisses M; Azevedo, Eduardo B

    2013-01-01

    This review assesses microwaves (MW) coupled to advanced oxidation processes (AOPs) for pollutants degradation, as well as the basic theory and mechanisms of MW dielectric heating. We addressed the following couplings: MW/H2O2, MW/UV/H2O2, MW/Fenton, MW/US, and MW/UV/TiO2, as well as few studies that tested alternative oxidants and catalysts. Microwave Discharge Electrodeless Lamps (MDELs) are being extensively used with great advantages over ballasts. In their degradation studies, researchers generally employed domestic ovens with minor adaptations. Non-thermal effects and synergies between UV and MW radiation play an important role in the processes. Published papers so far report degradation enhancements between 30 and 1,300%. Unfortunately, how microwaves enhance pollutants is still obscure and real wastewaters scarcely studied. Based on the results surveyed in the literature, MW/AOPs are promising alternatives for treating/remediating environmental pollutants, whenever one considers high degradation yields, short reaction times, and small costs.

  12. Inhibitory effect of natural organic matter or other background constituents on photocatalytic advanced oxidation processes: Mechanistic model development and validation.

    PubMed

    Brame, Jonathon; Long, Mingce; Li, Qilin; Alvarez, Pedro

    2015-11-01

    The ability of reactive oxygen species (ROS) to interact with priority pollutants is crucial for efficient water treatment by photocatalytic advanced oxidation processes (AOPs). However, background compounds in water such as natural organic matter (NOM) can significantly hinder targeted reactions and removal efficiency. This inhibition can be complex, interfering with degradation in solution and at the photocatalyst surface as well as hindering illumination efficiency and ROS production. We developed an analytical model to account for various inhibition mechanisms in catalytic AOPs, including competitive adsorption of inhibitors, scavenging of produced ROS at the surface and in solution, and the inner filtering of the excitation illumination, which combine to decrease ROS-mediated degradation. This model was validated with batch experiments using a variety of ROS producing systems (OH-generating TiO2 photocatalyst and H2O2-UV; (1)O2-generating photosensitive functionalized fullerenes and rose bengal) and inhibitory compounds (NOM, tert-butyl alcohol). Competitive adsorption by NOM and ROS scavenging were the most influential inhibitory mechanisms. Overall, this model enables accurate simulation of photocatalytic AOP performance when one or more inhibitory mechanisms are at work in a wide variety of application scenarios, and underscores the need to consider the effects of background constituents on degradation efficiency.

  13. Transformation of polyfluorinated compounds in natural waters by advanced oxidation processes.

    PubMed

    Anumol, Tarun; Dagnino, Sonia; Vandervort, Darcy R; Snyder, Shane A

    2016-02-01

    The presence of perfluorocarboxylic acids (PFCAs) in source and finished drinking waters is a concern with studies showing bioaccumulation and adverse toxicological effects in wildlife and potentially humans. Per/Polyfluoroalkyl substances (PFAS) such as fluorotelomer alcohols have been identified as precursors for PFCAs in biological pathways. In this study, we investigated the fate of 6:2 and 8:2 homologues of the fluorotelomer unsaturated carboxylic acids (FTUCAs) during advanced oxidation process (AOPs). Results showed 6:2 FTUCA and 8:2 FTUCA transformed into 6-C PFCA (PFHxA) and 8-C PFCA (PFOA) respectively with very little other PFCA formation for all AOPs. The degradation of 6:2 FTUCA and 8:2 FTUCA was greater in the GW compared to SW for the ozone processes but similar for UV/H2O2. The formation of n-C PFCA followed O3>O3/H2O2 at same dose and UV/H2O2 had much lower formation at the doses tested. Non-targeted analysis with the LC-MS-qTOF indicated the production of other PFCAs which contribute to the total mass balance, although no intermediate product was discovered indicating a rapid and direct transformation from the FTUCAs to the PFCAs and/or significant volatilization of intermediates. With the use of AOPs essential to water reuse treatment schemes, this work raises concerns over the risk of potential formation of PFCAs in the treatment and their adverse health effects in finished drinking water.

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

    PubMed

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

    2013-01-01

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

  15. Assessment of the UV/Cl2 advanced oxidation process for the degradation of the emerging contaminants amitriptyline hydrochloride, methyl salicylate and 2-phenoxyethanol in water systems.

    PubMed

    Javier Benitez, F; Real, Francisco J; Acero, Juan L; Casas, Francisco

    2016-12-26

    Three emerging contaminants (amitriptyline hydrochloride (AH), methyl salicylate (MS) and 2-phenoxyethanol (PE)) frequently found in wastewaters were selected to be individually degraded in ultra-pure water by the advanced oxidation process (AOP) constituted by the combination of UV radiation and chlorine. The influence of pH, initial chlorine concentration and nature of the contaminants was firstly explored. The trend for the reactivity of the selected compounds was deduced: AH > MS > PE. A later kinetic study was carried out focused on the evaluation of the first-order rate constants and the determination of the partial contribution to the global reaction of the direct photochemical pathway and the radical pathway. In a second stage, the simultaneous oxidation of mixtures of the selected contaminants in several types of water was also performed by the same combination UV/Cl2. The efficiency of this combined system UV/Cl2 was compared to other oxidants such as the UV/[Formula: see text] and UV/H2O2 AOPs, and the influence of the operating variables was discussed. Results confirmed that the UV/Cl2 system provides higher elimination efficiencies among the AOPs tested. The presence of dissolved organic matter and bicarbonate ions in the water matrix caused a decrease in the treatment efficiency.

  16. Removal of natural organic matter from drinking water by advanced oxidation processes.

    PubMed

    Matilainen, Anu; Sillanpää, Mika

    2010-06-01

    Over the past 10-20years the amount of the natural organic matter (NOM) has been increased in raw water supplies on several areas. The presence of NOM causes many problems in drinking water treatment processes, including: (i) negative effect on water quality by colour, taste and odor problems, (ii) increased coagulant and disinfectant dose requirements (which in turn results increased sludge and potential harmful disinfection by-product formation), (iii) promoted biological growth in distribution system, and (iv) increased levels of complexed heavy metals and adsorbed organic pollutants. Thus, more efficient methods for the removal of NOM have emerged. Among these are advanced oxidation processes (AOPs). These include O(3)/H(2)O(2), O(3)/UV, UV/H(2)O(2), TiO(2)/UV, H(2)O(2)/catalyst, Fenton and photo-Fenton prosesses as well as ultrasound. In the present work, an overview of the recent research studies dealing with AOP methods for the removal of NOM and related compounds from drinking water is presented.

  17. A comparative study of different tests for biodegradability enhancement determination during AOP treatment of recalcitrant toxic aqueous solutions.

    PubMed

    Ballesteros Martín, M M; Casas López, J L; Oller, I; Malato, S; Sánchez Pérez, J A

    2010-09-01

    Four biodegradability tests (Pseudomonas putida bioassay, Zahn-Wellens test, BOD5/COD ratio and respirometry assay) have been used to determine the biodegradability enhancement during the treatment of wastewater containing 200 mg L(-1) of dissolved organic carbon (DOC) of a five commercial pesticides mixture (Vydate, Metomur, Couraze, Ditumur and Scala) by an advanced oxidation process (AOP). A comparative study was carried out taking into account repeatability and precision of each biodegradability test. Solar photo-Fenton was the AOP selected for pesticide degradation up to three levels of mineralization: 20%, 40% and 60% of initial DOC. Intra- and interday precisions were evaluated conducting each biodegradability test by triplicate and they were applied three times on different dates over a period of three months. Fisher's least significant difference method was applied to the means, P. putida and Zahn-Wellens tests giving higher repeatability and precision. The P. putida test requires a shorter time to obtain reliable results using a standardized inoculum and constitutes a worthwhile alternative to estimate biodegradability in contrast to other less accurate or more time consuming methods.

  18. Comparison of various advanced oxidation processes for the degradation of phenylurea herbicides.

    PubMed

    Kovács, Krisztina; Farkas, János; Veréb, Gábor; Arany, Eszter; Simon, Gergő; Schrantz, Krisztina; Dombi, András; Hernádi, Klára; Alapi, Tünde

    2016-01-01

    Various types of advanced oxidation processes (AOPs), such as UV photolysis, ozonation, heterogeneous photocatalysis and their combinations were comparatively examined at the same energy input in a home-made reactor. The oxidative transformations of the phenylurea herbicides fenuron, monuron and diuron were investigated. The initial rates of transformation demonstrated that UV photolysis was highly efficient in the cases of diuron and monuron. Ozonation proved to be much more effective in the transformation of fenuron than in those of the chlorine containing monuron and diuron. In heterogeneous photocatalysis, the rate of decomposition decreased with increase of the number of chlorine atoms in the target molecule. Addition of ozone to UV-irradiated solutions and/or TiO2-containing suspensions markedly increased the initial rates of degradation. Dehalogenation of monuron and diuron showed that each of these procedures is suitable for the simultaneous removal of chlorinated pesticides and their chlorinated intermediates. Heterogeneous photocatalysis was found to be effective in the mineralization.

  19. Advanced oxidation processes coupled with electrocoagulation for the exhaustive abatement of Cr-EDTA.

    PubMed

    Durante, Christian; Cuscov, Marco; Isse, Abdirisak Ahmed; Sandonà, Giancarlo; Gennaro, Armando

    2011-02-01

    Using Cr-EDTA as a model system, a two-step method has been investigated for the abatement of persistent chromium complexes in water. The treatment consists of an oxidative decomposition of the organic ligands by means of ozonization or electrochemical oxidation at a boron doped diamond (BDD) electrode, followed by removal of the metal via electrochemical coagulation. In the designed synthetic waste, EDTA has been used both as a chelating agent and as a mimic of the organic content of a typical wastewater provided by a purification leather plant. A crucial point evaluated is the influence of the oxidative pretreatment on the chemical modification of the synthetic waste and hence on the electrocoagulation efficacy. Because of the great stability of Cr complexes, such as Cr-EDTA, the classical coagulation methods, based on ligand exchange between Cr(III) and Fe(II) or Fe(III), are ineffective toward Cr abatement in the presence of organic substances. On the contrary, when advanced oxidation processes (AOPs), such as ozonization or electrooxidation at a BDD anode are applied in series with electrocoagulation (EC), complete abatement of the recalcitrant Cr fraction can be achieved. ECs have been carried out by using Fe sacrificial anodes, with alternating polarization and complete Cr abatement (over 99%) has been obtained with modest charge consumption. It has been found that Cr(III) is first oxidized to Cr(VI) in the AOP preceding EC. Then, during EC, Cr(VI) is mainly reduced back to Cr(III) by electrogenerated Fe(II). Thus, Cr is mainly eliminated as Cr(III). However, a small fraction of Cr(VI) goes with the precipitate as confirmed by XPS analysis of the sludge.

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

    SciTech Connect

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

    2013-07-01

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

  1. Treating solid dairy manure using microwave-enhanced advanced oxidation process.

    PubMed

    Kenge, Anju A; Liao, Ping H; Lo, Kwang V

    2009-08-01

    The microwave enhanced advanced oxidation process (MW/H(2)O(2)-AOP) was used to treat separated solid dairy manure for nutrient release and solids reduction. The MW/H(2)O(2)-AOP was conducted at a microwave temperature of 120 degrees C for 10 minutes, and at three pH conditions of 3.5, 7.3 and 12. The hydrogen peroxide dosage at approximately 2 mL per 1% TS for a 30 mL sample was used in this study, reflecting a range of 0.53-0.75 g H(2)O(2)/g dry sludge. The results indicated that substantial quantities of nutrients could be released into the solution at pH of 3.5. However, at neutral and basic conditions only volatile fatty acids and soluble chemical oxygen demand could be released. The analyses on orthophosphate, soluble chemical oxygen demands and volatile fatty acids were re-examined for dairy manure. It was found that the orthophosphate concentration for untreated samples at a higher % total solids (TS) was suppressed and lesser than actual. To overcome this difficulty, the initial orthophosphate concentration had to be measured at 0.5% TS.

  2. Microwave enhanced advanced oxidation process for treating dairy manure at low pH.

    PubMed

    Lo, Kwang V; Chan, Winnie W I; Yawson, Selina K; Liao, Ping H

    2012-01-01

    This study investigated the treatment of dairy manure using the microwave enhanced advanced oxidation process (MW-AOP) at pH 2. An experimental design was developed based on a statistical program using response surface methodology to explore the effects of temperature, hydrogen peroxide dosage and heating time on sugar production, nutrient release and solids destruction. Temperature, hydrogen peroxide dosage and acid concentration were key factors affecting reducing sugar production. The highest reducing sugar yield of 7.4% was obtained at 160°C, 0 mL, 15 min heating time, and no H(2)O(2) addition. Temperature was a dominant factor for an increase of soluble chemical oxygen demand (SCOD) in the treated dairy manure. The important factors for volatile fatty acids (VFA) production were microwave temperature and hydrogen peroxide dosage. Temperature was the most important parameter, and heating time, to a lesser extent affecting orthophosphate release. Heating time, hydrogen peroxide dosage and temperature were significant factors for ammonia release. There was a maximum of 96% and 196% increase in orthophosphate and ammonia concentration, respectively at 160°C, 0.5 mL H(2)O(2) and 15 min heating time. The MW-AOP is an effective method in dairy manure treatment for sugar production, nutrient solubilisation, and solids disintegration.

  3. Demonstrating sucralose as a monitor of full-scale UV/AOP treatment of trace organic compounds.

    PubMed

    Lester, Yaal; Ferrer, Imma; Thurman, E Michael; Linden, Karl G

    2014-09-15

    Due to the large number of trace organic compounds (TOrCs) in water and wastewater, their degradation during UV-based advanced oxidation (UV/AOP) is best monitored using a conservative indicator compound. The present study demonstrates the in situ use of sucralose, a widely consumed artificial sweetener, as a conservative probe for UV/AOP degradation of TOrCs. The main qualities of sucralose in this regard are its high concentration in wastewater effluent and surface water (enabling its direct detection), its resistance to direct UV photolysis, and its relatively slow reaction with hydroxyl radical. Degradation of sucralose was compared to the degradation of commonly detected TOrCs, across two AOPs (i.e. UV/H2O2 and UV/NO3), in both lab-scale and pilot-scale systems. In all cases, UV/AOP degradation of sucralose was slower than the degradation of the examined TOrCs, and is expected to be slower than the degradation of the majority of other environmentally relevant TOrCs. These results demonstrate the potential of sucralose as a conservative probe, to monitor the transformation of TOrCs during UV/AOP treatment. Furthermore, degradation of sucralose was slower than the degradation of many transformation products (generated during oxidation of TOrCs), implying that sucralose is also a valuable indicator for the decay of primary transformation products.

  4. Exposure and Dosimetry Considerations for Adverse Outcome Pathways (AOPs) (NIH-AOP)

    EPA Science Inventory

    Risk is a function of both of hazard and exposure. Toxicokinetic (TK) models can determine whether chemical exposures produce potentially hazardous tissue concentrations. Whether or not the initial molecular event (MIE) in an Adverse Outcome Pathway (AOP) occurs depends on both e...

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

    PubMed

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

    2008-12-30

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

  6. Decomposition of two haloacetic acids in water using UV radiation, ozone and advanced oxidation processes.

    PubMed

    Wang, Kunping; Guo, Jinsong; Yang, Min; Junji, Hirotsuji; Deng, Rongsen

    2009-03-15

    The decomposition of two haloacetic acids (HAAs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), from water was studied by means of single oxidants: ozone, UV radiation; and by the advanced oxidation processes (AOPs) constituted by combinations of O(3)/UV radiation, H(2)O(2)/UV radiation, O(3)/H(2)O(2), O(3)/H(2)O(2)/UV radiation. The concentrations of HAAs were analyzed at specified time intervals to elucidate the decomposition of HAAs. Single O(3) or UV did not result in perceptible decomposition of HAAs within the applied reaction time. O(3)/UV showed to be more suitable for the decomposition of DCAA and TCAA in water among the six methods of oxidation. Decomposition of DCAA was easier than TCAA by AOPs. For O(3)/UV in the semi-continuous mode, the effective utilization rate of ozone for HAA decomposition decreased with ozone addition. The kinetics of HAAs decomposition by O(3)/UV and the influence of coexistent humic acids and HCO(3)(-) on the decomposition process were investigated. The decomposition of the HAAs by the O(3)/UV accorded with the pseudo-first-order mode under the constant initial dissolved O(3) concentration and fixed UV radiation. The pseudo-first-order rate constant for the decomposition of DCAA was more than four times that for TCAA. Humic acids can cause the H(2)O(2) accumulation and the decrease in rate constants of HAAs decomposition in the O(3)/UV process. The rate constants for the decomposition of DCAA and TCAA decreased by 41.1% and 23.8%, respectively, when humic acids were added at a concentration of 1.2mgTOC/L. The rate constants decreased by 43.5% and 25.9%, respectively, at an HCO(3)(-) concentration of 1.0mmol/L.

  7. Treatment of rice straw hemicellulosic hydrolysates with advanced oxidative processes: a new and promising detoxification method to improve the bioconversion process

    PubMed Central

    2013-01-01

    Background The use of lignocellulosic constituents in biotechnological processes requires a selective separation of the main fractions (cellulose, hemicellulose and lignin). During diluted acid hydrolysis for hemicellulose extraction, several toxic compounds are formed by the degradation of sugars and lignin, which have ability to inhibit microbial metabolism. Thus, the use of a detoxification step represents an important aspect to be considered for the improvement of fermentation processes from hydrolysates. In this paper, we evaluated the application of Advanced Oxidative Processes (AOPs) for the detoxification of rice straw hemicellulosic hydrolysate with the goal of improving ethanol bioproduction by Pichia stipitis yeast. Aiming to reduce the toxicity of the hemicellulosic hydrolysate, different treatment conditions were analyzed. The treatments were carried out according to a Taguchi L16 orthogonal array to evaluate the influence of Fe+2, H2O2, UV, O3 and pH on the concentration of aromatic compounds and the fermentative process. Results The results showed that the AOPs were able to remove aromatic compounds (furan and phenolic compounds derived from lignin) without affecting the sugar concentration in the hydrolysate. Ozonation in alkaline medium (pH 8) in the presence of H2O2 (treatment A3) or UV radiation (treatment A5) were the most effective for hydrolysate detoxification and had a positive effect on increasing the yeast fermentability of rice straw hemicellulose hydrolysate. Under these conditions, the higher removal of total phenols (above 40%), low molecular weight phenolic compounds (above 95%) and furans (above 52%) were observed. In addition, the ethanol volumetric productivity by P. stipitis was increased in approximately twice in relation the untreated hydrolysate. Conclusion These results demonstrate that AOPs are a promising methods to reduce toxicity and improve the fermentability of lignocellulosic hydrolysates. PMID:23414668

  8. Building gene expression signatures indicative of transcription factor activation to predict AOP modulation

    EPA Science Inventory

    Building gene expression signatures indicative of transcription factor activation to predict AOP modulation Adverse outcome pathways (AOPs) are a framework for predicting quantitative relationships between molecular initiatin...

  9. Studies on degradation of glyphosate by several oxidative chemical processes: ozonation, photolysis and heterogeneous photocatalysis.

    PubMed

    Assalin, Marcia R; De Moraes, Sandra G; Queiroz, Sonia C N; Ferracini, Vera L; Duran, Nelson

    2010-01-01

    Several different Advanced Oxidation Processes (AOPs) including ozonation at pH 6.5 and 10, photolysis and heterogeneous photocatalysis using TiO(2) as semiconductor and dissolved oxygen as electron acceptor were applied to study the degradation of glyphosate (N-phosphonomethyl glycine) in water. The degree of glyphosate degradation, the reactions kinetic and the formation of the major metabolite, aminomethyl phosphonic acid (AMPA), were evaluated. Ozonation at pH 10 resulted in the maximum mineralization of glyphosate. It was observed that under the experimental conditions used in this study the degradation of glyphosate followed the first-order kinetics. The half-life obtained for glyphosate degradation in the O(3)/pH 10 process was 1.8 minutes.

  10. Bilateral thalamic infarction and DSA demonstrated AOP after thrombosis.

    PubMed

    Cao, Wenjie; Dong, Qiang; Li, Linxin; Dong, Yi

    2012-01-01

    Bilateral paramedian thalamic stroke is a special ischemic pattern that results from occlusion of the artery of Percheron (AOP), a rare anatomic variant of the paramedian arteries. We report a case of bilateral thalamic infarctions, with a dramatic improvement after thrombolysis. DSA demonstrated recanalization of AOP with possible unreported variation.

  11. Bilateral thalamic infarction and DSA demonstrated AOP after thrombosis

    PubMed Central

    Cao, Wenjie; Dong, Qiang; Li, Linxin; Dong, Yi

    2012-01-01

    Bilateral paramedian thalamic stroke is a special ischemic pattern that results from occlusion of the artery of Percheron (AOP), a rare anatomic variant of the paramedian arteries. We report a case of bilateral thalamic infarctions, with a dramatic improvement after thrombolysis. DSA demonstrated recanalization of AOP with possible unreported variation. PMID:23986825

  12. Catalytic oxidative dehydrogenation process

    DOEpatents

    Schmidt, Lanny D.; Huff, Marylin

    2002-01-01

    A process for the production of a mono-olefin from a gaseous paraffinic hydrocarbon having at least two carbon atoms or mixtures thereof comprising reacting said hydrocarbons and molecular oxygen in the presence of a platinum catalyst. The catalyst consist essentially of platinum supported on alumina or zirconia monolith, preferably zirconia and more preferably in the absence of palladium, rhodium and gold.

  13. The Advanced On-board Processor (AOP)

    NASA Technical Reports Server (NTRS)

    Hartenstein, R. G.; Trevathan, C. E.; Stewart, W. N.

    1971-01-01

    The goal of the Advanced On-Board Processor (AOP) development program is to design, build, and flight qualify a highly reliable, moderately priced, digital computer for application on a variety of spacecraft. Included in this development program is the preparation of a complete support software package which consists of an assembler, simulator, loader, system diagnostic, operational executive, and many useful subroutines. The AOP hardware/software system is an extension of the On-Board Processor (OBP) which was developed for general purpose use on earth orbiting spacecraft with its initial application being on-board the fourth Orbiting Astronomical Observatory (OAO-C). Although the OBP possesses the significant features that are required for space application, however, when operating at 100% duty cycle the OBP is too power-consuming for use on many smaller spacecraft. Computer volume will be minimized by implementing the processor and input/output portions of the machine with large scale integrated circuits. Power consumption will be reduced through the use of plated wire and, in some cases, semiconductor memory elements.

  14. Suitable conditions for advanced oxidation process by the amount of ozone reaction and the amount of dioxin degradation in landfill leachate

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Katsuhiko; Kanjo, Yoshinori; Matsufuji, Yasushi; Fukunaga, Isao; Urabe, Shinro; Yagi, Yoshio

    One of the processes to degrade dioxin in landfill leachate is the AOP(advanced oxidation process) method that uses ultraviolet rays or hydrogen peroxide together with ozone. In this research, we used the experimental result of the AOP method and applied to various kinds of experimental systems to determine the relationship between the amount of ozone reaction and the amount of dioxin degradation. The main results were as follows: The TOC(Total Organic Carbon) in the raw leachate consumed the supplied ozone by approximately 3.1(mgO3/mgTOC). It could be expressed in a linear equation between the ozone reaction amount revised by the TOC and the amount of dioxin degradation, and the slope was about 11.5(pgDXN/mgO3). A function of AOP can be expressed by comparing the quantity of suitable ozone reaction to the dioxin degradation. From the degradation ratio of each homologs, the degradation is mainly caused by the hydroxyl radical. To follow the dioxin discharge standard value, it is sufficient to guarantee the revised ozone reaction amount is more than 200mg/l.

  15. A novel liquid plasma AOP device integrating microwaves and ultrasounds and its evaluation in defluorinating perfluorooctanoic acid in aqueous media.

    PubMed

    Horikoshi, Satoshi; Sato, Susumu; Abe, Masahiko; Serpone, Nick

    2011-09-01

    A simplified and energy-saving integrated device consisting of a microwave applicator and an ultrasonic homogenizer has been fabricated to generate liquid plasma in a medium possessing high dielectric factors, for example water. The microwave waveguide and the ultrasonic transducer were interconnected through a tungsten/titanium alloy stick acting both as the microwave antenna and as the horn of the ultrasonic homogenizer. Both microwaves and ultrasonic waves are simultaneously transmitted to the aqueous media through the tungsten tip of the antenna. The microwave discharge liquid plasma was easily generated in solution during ultrasonic cavitation. The simple device was evaluated by carrying out the degradation of the perfluorooctanoic acid (PFOA), a system highly recalcitrant to degradation by conventional advanced oxidation processes (AOPs). PFOA is 59% degraded in an aqueous medium after only 90 s of irradiation by the plasma. Intermediates were identified by electrospray mass spectral techniques in the negative ion mode.

  16. Transformation of Contaminant Candidate List (CCL3) compounds during ozonation and advanced oxidation processes in drinking water: Assessment of biological effects.

    PubMed

    Mestankova, Hana; Parker, Austa M; Bramaz, Nadine; Canonica, Silvio; Schirmer, Kristin; von Gunten, Urs; Linden, Karl G

    2016-04-15

    The removal of emerging contaminants during water treatment is a current issue and various technologies are being explored. These include UV- and ozone-based advanced oxidation processes (AOPs). In this study, AOPs were explored for their degradation capabilities of 25 chemical contaminants on the US Environmental Protection Agency's Contaminant Candidate List 3 (CCL3) in drinking water. Twenty-three of these were found to be amenable to hydroxyl radical-based treatment, with second-order rate constants for their reactions with hydroxyl radicals (OH) in the range of 3-8 × 10(9) M(-1) s(-1). The development of biological activity of the contaminants, focusing on mutagenicity and estrogenicity, was followed in parallel with their degradation using the Ames and YES bioassays to detect potential changes in biological effects during oxidative treatment. The majority of treatment cases resulted in a loss of biological activity upon oxidation of the parent compounds without generation of any form of estrogenicity or mutagenicity. However, an increase in mutagenic activity was detected by oxidative transformation of the following CCL3 parent compounds: nitrobenzene (OH, UV photolysis), quinoline (OH, ozone), methamidophos (OH), N-nitrosopyrolidine (OH), N-nitrosodi-n-propylamine (OH), aniline (UV photolysis), and N-nitrosodiphenylamine (UV photolysis). Only one case of formation of estrogenic activity was observed, namely, for the oxidation of quinoline by OH. Overall, this study provides fundamental and practical information on AOP-based treatment of specific compounds of concern and represents a framework for evaluating the performance of transformation-based treatment processes.

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

    PubMed

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

    2017-01-01

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

  18. Evaluation of copper slag to catalyze advanced oxidation processes for the removal of phenol in water.

    PubMed

    Huanosta-Gutiérrez, T; Dantas, Renato F; Ramírez-Zamora, R M; Esplugas, S

    2012-04-30

    The aim of this work was to evaluate the use of copper slag to catalyze phenol degradation in water by advanced oxidation processes (AOPs). Copper slag was tested in combination with H(2)O(2) (slag/H(2)O(2)) and H(2)O(2)/UV (slag/H(2)O(2)/UV). The studied methods promoted the complete photocatalytic degradation of phenol. Besides, they were able to reduce about 50% the TOC content in the samples. Slag/H(2)O(2)/UV and slag/H(2)O(2) treatments have favored biodegradability increment along the reaction time. Nevertheless, the irradiated method achieved higher values of the biodegradability indicator (BOD(5)/TOC). The toxicity assessment indicated the formation of more toxic compounds in both treatments. However, the control of the reaction time would minimize the environmental impact of the effluents.

  19. Development of Predictive Models for the Degradation of Halogenated Disinfection Byproducts during the UV/H2O2 Advanced Oxidation Process.

    PubMed

    Chuang, Yi-Hsueh; Parker, Kimberly M; Mitch, William A

    2016-10-18

    Previous research has demonstrated that the reverse osmosis and advanced oxidation processes (AOPs) used to purify municipal wastewater to potable quality have difficulty removing low molecular weight halogenated disinfection byproducts (DBPs) and industrial chemicals. Because of the wide range of chemical characteristics of these DBPs, this study developed methods to predict their degradation within the UV/H2O2 AOP via UV direct photolysis and hydroxyl radical ((•)OH) reaction, so that DBPs most likely to pass through the AOP could be predicted. Among 26 trihalomethanes, haloacetonitriles, haloacetaldehydes, halonitromethanes and haloacetamides, direct photolysis rate constants (254 nm) varied by ∼3 orders of magnitude, with rate constants increasing with Br and I substitution. Quantum yields varied little (0.12-0.59 mol/Einstein), such that rate constants were driven by the orders of magnitude variation in molar extinction coefficients. Quantum chemical calculations indicated a strong correlation between molar extinction coefficients and decreasing energy gaps between the highest occupied and lowest unoccupied orbitals (i.e., ELUMO-EHOMO). Rate constants for 37 trihalomethanes, haloacetonitriles, haloacetaldehydes, halonitromethanes, haloacetamides, and haloacetic acids with (•)OH measured by gamma radiolysis spanned 4 orders of magnitude. Based on these rate constants, a quantitative structure-reactivity relationship model (Group Contribution Method) was developed which predicted (•)OH rate constants for 5 additional halogenated compounds within a factor of 2. A kinetics model combining the molar extinction coefficients, quantum yields and (•)OH rate constants predicted experimental DBP loss in a lab-scale UV/H2O2 AOP well. Highlighting the difficulty associated with degrading these DBPs, at the 500-1000 mJ/cm(2) UV fluence applied in potable reuse trains, 50% removal would be achieved generally only for compounds with several -Br or -I substituents

  20. Review of iron-free Fenton-like systems for activating H2O2 in advanced oxidation processes.

    PubMed

    Bokare, Alok D; Choi, Wonyong

    2014-06-30

    Iron-catalyzed hydrogen peroxide decomposition for in situ generation of hydroxyl radicals (HO(•)) has been extensively developed as advanced oxidation processes (AOPs) for environmental applications. A variety of catalytic iron species constituting metal salts (in Fe(2+) or Fe(3+) form), metal oxides (e.g., Fe2O3, Fe3O4), and zero-valent metal (Fe(0)) have been exploited for chemical (classical Fenton), photochemical (photo-Fenton) and electrochemical (electro-Fenton) degradation pathways. However, the requirement of strict acidic conditions to prevent iron precipitation still remains the bottleneck for iron-based AOPs. In this article, we present a thorough review of alternative non-iron Fenton catalysts and their reactivity towards hydrogen peroxide activation. Elements with multiple redox states (like chromium, cerium, copper, cobalt, manganese and ruthenium) all directly decompose H2O2 into HO(•) through conventional Fenton-like pathways. The in situ formation of H2O2 and decomposition into HO(•) can be also achieved using electron transfer mechanism in zero-valent aluminum/O2 system. Although these Fenton systems (except aluminum) work efficiently even at neutral pH, the H2O2 activation mechanism is very specific to the nature of the catalyst and critically depends on its composition. This review describes in detail the complex mechanisms and emphasizes on practical limitations influencing their environmental applications.

  1. Feasibility studies: UV/chlorine advanced oxidation treatment for the removal of emerging contaminants.

    PubMed

    Sichel, C; Garcia, C; Andre, K

    2011-12-01

    UV/chlorine (UV/HOCl and UV/ClO(2)) Advanced Oxidation Processes (AOPs) were assessed with varying process layout and compared to the state of the art UV/H(2)O(2) AOP. The process comparison focused on the economical and energy saving potential of the UV/chlorine AOP. Therefore the experiments were performed at technical scale (250 L/h continuous flow reactor) and at process energies, oxidant and model contaminant concentrations expected in full scale reference plants. As model compounds the emerging contaminants (ECs): desethylatrazine, sulfamethoxazole, carbamazepine, diclofenac, benzotriazole, tolyltriazole, iopamidole and 17α-ethinylestradiol (EE2) were degraded at initial compound concentrations of 1 μg/L in tap water and matrixes with increased organic load (46 mg/L DOC). UV/chlorine AOP organic by-product forming potential was assessed for trihalomethanes (THMs) and N-Nitrosodimethylamine (NDMA). A process design was evaluated which can considerably reduce process costs, energy consumption and by-product generation from UV/HOCl AOPs.

  2. The use of artificial neural network (ANN) for the prediction and simulation of oil degradation in wastewater by AOP.

    PubMed

    Mustafa, Yasmen A; Jaid, Ghydaa M; Alwared, Abeer I; Ebrahim, Mothana

    2014-06-01

    The application of advanced oxidation process (AOP) in the treatment of wastewater contaminated with oil was investigated in this study. The AOP investigated is the homogeneous photo-Fenton (UV/H2O2/Fe(+2)) process. The reaction is influenced by the input concentration of hydrogen peroxide H2O2, amount of the iron catalyst Fe(+2), pH, temperature, irradiation time, and concentration of oil in the wastewater. The removal efficiency for the used system at the optimal operational parameters (H2O2 = 400 mg/L, Fe(+2) = 40 mg/L, pH = 3, irradiation time = 150 min, and temperature = 30 °C) for 1,000 mg/L oil load was found to be 72%. The study examined the implementation of artificial neural network (ANN) for the prediction and simulation of oil degradation in aqueous solution by photo-Fenton process. The multilayered feed-forward networks were trained by using a backpropagation algorithm; a three-layer network with 22 neurons in the hidden layer gave optimal results. The results show that the ANN model can predict the experimental results with high correlation coefficient (R (2) = 0.9949). The sensitivity analysis showed that all studied variables (H2O2, Fe(+2), pH, irradiation time, temperature, and oil concentration) have strong effect on the oil degradation. The pH was found to be the most influential parameter with relative importance of 20.6%.

  3. Degradation of the cytostatic 5-Fluorouracil in water by Fenton and photo-assisted oxidation processes.

    PubMed

    Governo, Mariana; Santos, Mónica S F; Alves, Arminda; Madeira, Luís M

    2017-01-01

    Cytostatics are part of the forefront research topics due to their high prescription, high toxicity, and the lack of effective solutions to stop their entrance and spread in the environment. Among them, 5-Fluorouracil (5-Fu) has received particular attention because is one of the most prescribed active substances in chemotherapy worldwide. The degradation of 5-Fu by advanced oxidation processes (AOPs) is a poorly addressed topic, and this work brings valuable inputs concerning this matter. Herein, the efficacy of Fenton's process in the degradation of 5-Fu is explored for the first time; the study of the main variables and its successful application to the treatment of real wastewaters is demonstrated. Moreover, hydrogen peroxide-based and photo-assisted techniques (direct photolysis, photodegradation with H2O2 and photo-Fenton) are also investigated for purposes of comparison. Under the best operation conditions obtained (T = 30 °C, [Fe(2+)]0 = 0.5 mM; [H2O2]0 = 240 mM and pH = 3 for [5-Fu]0 = 0.38 mM), 5-Fu was completely eliminated after 2 h of Fenton's reaction and about 50 % of mineralization was reached after 8 h. The best performance was obtained by the photo-Fenton process, with 5-Fu mineralization level as high as 67 %, using an iron dose within the legal limits required for direct water discharge. Toxicity (towards Vibrio fischeri) of the effluents that resulted from the application of the above-mentioned AOPs was also evaluated; it was found that the degradation products generated from the photo-assisted processes are less toxic than the parent compound, putting into evidence the relevance of such technologies for degradation of cytostatics like 5-Fu.

  4. Adverse outcome pathway (AOP) development I: Strategies and principles

    EPA Science Inventory

    An adverse outcome pathway (AOP) is a conceptual framework that organizes existing knowledge concerning biologically plausible, and empirically-supported, links between molecular-level perturbation of a biological system and an adverse outcome at a level of biological organizatio...

  5. Adverse outcome pathway (AOP) development: Guiding principles and best practices

    EPA Science Inventory

    Adverse outcome pathways (AOPs) represent a conceptual framework that can support greater application of mechanistic data in regulatory decision-making. However, in order for the scientific community to collectively address the daunting challenge of describing relevant toxicologi...

  6. Adverse outcome pathway (AOP) development II: Best practices

    EPA Science Inventory

    Organization of existing and emerging toxicological knowledge into adverse outcome pathway (AOP) descriptions can facilitate greater application of mechanistic data, including high throughput in vitro, high content omics and imaging, and biomarkers, in risk-based decision-making....

  7. Kinetics and mechanisms of cylindrospermopsin destruction by sulfate radical-based advanced oxidation processes.

    PubMed

    He, Xuexiang; de la Cruz, Armah A; O'Shea, Kevin E; Dionysiou, Dionysios D

    2014-10-15

    Cylindrospermopsin (CYN) is a potent cyanobacterial toxin frequently found in water bodies worldwide raising concerns over the safety of drinking and recreational waters. A number of technologies have been investigated to remove and/or degrade cyanotoxins with advanced oxidation processes (AOPs) being among the most promising and effective for water detoxification. In this study, the degradation of CYN by sulfate radical-based UV-254 nm-AOPs was evaluated. The UV/S2O8(2-) (UV/peroxydisulfate) was more efficient than UV/HSO5(-) (UV/peroxysulfate) and UV/H2O2 (UV/hydrogen peroxide) processes when natural water samples were used as reaction matrices. The observed UV fluence based pseudo-first-order rate constants followed the expected order of radical quantum yields. The presence of 200 μM natural organic matter (NOM) as carbon slightly inhibited the destruction of CYN; 1.24 mg L(-1)NO3(-) (nitrate) had no significant influence on the removal efficiency and 50 μg L(-1) Fe(2+) [iron (2+)] or Cu(2+) [copper (2+)] improved the performance of UV/S2O8(2-). The addition of tert-butyl alcohol (t-BuOH; hydroxyl radical scavenger) in the reaction yielded byproducts that indicated specific sites in CYN preferentially attacked by sulfate radicals (SRs). The predominant CYN degradation byproduct was P448 consistent with fragmentation of the C5C6 bond of the uracil ring. The subsequent formation of P420 and P392 through a stepwise loss of carbonyl group(s) further supported the fragmentation pathway at C5C6. The byproduct P432 was identified exclusively as mono-hydroxylation of CYN at tricyclic guanidine ring, whereas P414 was detected as dehydrogenation at the tricyclic ring. The elimination of sulfate group and the opening of tricyclic ring were also observed. The possible degradation pathways of CYN by SR-AOP were presented.

  8. Adverse Outcome Pathway (AOP) for a Mutagenic Mode of ...

    EPA Pesticide Factsheets

    AOPs provide a framework to describe a sequence of measureable key events (KEs), beginning with a molecular initiating event (MIE), followed by a series of identified KEs linked to one another by KE Relationships (KERs), all anchored by a specific adverse outcome (AO). Each KE/KER is supported by data and evaluated against criteria to assess biological plausibility, weight/strength of evidence, specificity, and confidence. AOPs offer an approach to using toxicological data and predictive modeling to actualize use of mode-of-action (MOA) for such purposes as read-across, integrated approaches to testing & assessment, and risk assessment. Different applications will depend partly on the scientific confidence underpinning each KE/KER and the overall AOP. An OECD program encourages development of AOPs, with a wiki that allows for public review & comment to foster collaborations and broaden understanding & application of AOPs. Developing an AOP for a mutagenic MOA for cancer as a case study in the OECD program lays a path towards determination of such an MOA and its use in chemical assessment programs. Aflatoxin B1 (AFB1), with ubiquitous exposure and a rich database, was selected for this case study. AFB1 has been determined to induce HCC via a DNA-reactive MOA in many species, including humans. The sequential KEs identified for AFB1 are as follows: pre-MIE: Hepatic metabolic activation; MIE: Formation of a pro-mutagenic DNA adduct (N7-AFB1-guanine or AFB1-FAPy); KE

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

    PubMed

    Pešoutová, Radka; Stříteský, Luboš; Hlavínek, Petr

    2014-01-01

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

  10. Integrated processes for produced water polishing: Enhanced flotation/sedimentation combined with advanced oxidation processes.

    PubMed

    Jiménez, Silvia; Micó, María M; Arnaldos, Marina; Ferrero, Enrique; Malfeito, Jorge J; Medina, Francisco; Contreras, Sandra

    2017-02-01

    In this study, bench scale dissolved air flotation (DAF) and settling processes have been studied and compared to a novel flotation technology based on the use of glass microspheres of limited buoyancy and its combination with conventional DAF, (Enhanced DAF or E-DAF). They were evaluated as pretreatments for advanced oxidation processes (AOPs) to polish produced water (PW) for reuse purposes. Settling and E-DAF without air injection showed adequate turbidity and oil and grease (O&G) removals, with eliminations higher than 87% and 90% respectively, employing 70 mg L(-1) of FeCl3 and 83 min of settling time, and 57.9 mg L(-1) of FeCl3, 300 mg L(-1) of microspheres and a flocculation rate of 40 rpm in the E-DAF process. A linear correlation was observed between final O&G concentration and turbidity after E-DAF. In order to polish the O&G content of the effluent even further, to remove soluble compounds as phenol and to take advantage of residual iron after these treatments, Fenton and photo-Fenton reactions were essayed. After 6 h of the Fenton reaction at pH 3, the addition of 1660 mg L(-1) of H2O2 and 133 mg L(-1) of iron showed a maximum O&G elimination of 57.6% and a phenol removal up to 80%. Photo-Fenton process showed better results after 3 h, adding 600 mg L(-1) of H2O2 and 300 mg L(-1) of iron, at pH 3, with a higher fraction of elimination of the O&G content (73.7%) and phenol (95%) compared to the conventional Fenton process.

  11. Application of advanced oxidation processes for cleaning of industrial water generated in wet dedusting of shaft furnace gases.

    PubMed

    Czaplicka, Marianna; Kurowski, Ryszard; Jaworek, Katarzyna; Bratek, Łukasz

    2013-01-01

    The paper presents results of studies into advanced oxidation processes in 03 and 03/UV systems. An advanced oxidation process (AOP) was conducted to reduce the load of impurities in circulating waters from wet de-dusting of shaft furnace gases. Besides inorganic impurities, i.e. mainly arsenic compounds (16 g As L(-1) on average), lead, zinc, chlorides and sulphates, the waters also contain some organic material. The organic material is composed of a complex mixture that contains, amongst others, aliphatic compounds, phenol and its derivatives, pyridine bases, including pyridine, and its derivatives. The test results show degradation of organic and inorganic compounds during ozonation and photo-oxidation processes. Analysis of the solutions from the processes demonstrated that the complex organic material in the industrial water was oxidized in ozonation and in photo-oxidation, which resulted in formation of aldehydes and carboxylic acids. Kinetic degradation of selected pollutants is presented. Obtained results indicated that the O3/UV process is more effective in degradation of organic matter than ozonation. Depending on the process type, precipitation of the solid phase was observed. The efficiency of solid-phase formation was higher in photo-oxidation with ozone. It was found that the precipitated solid phase is composed mainly of arsenic, iron and oxygen.

  12. Pilot-scale UV/H2O2 advanced oxidation process for surface water treatment and downstream biological treatment: effects on natural organic matter characteristics and DBP formation potential.

    PubMed

    Sarathya, Siva R; Stefan, Mihaela I; Royce, Alan; Mohseni, M

    2011-12-01

    The effects of the advanced oxidation process (AOP) of ultraviolet radiation in combination with hydrogen peroxide (UV/H2O2) on the structure and biodegradability of dissolved natural organic matter (NOM) and on the formation of disinfection by-products (DBPs) through the post-UV/H2O2 chlorination were investigated using UV reactors equipped with either low-pressure amalgam lamps or medium-pressure mercury vapour lamps. With electrical energy doses and H2O2 concentrations typically applied in full-scale UV systems for water remediation, the UV/H2O2 AOP partially oxidized NOM, reducing its degree of aromaticity and leading to an increase in the level of biodegradable species. Also, when combined with a downstream biological activated carbon (BAC) filter, UV/H2O2 AOP reduced the formation of DBPs by up to 60% for trihalomethanes and 75% for haloacetic acids. Biological activated carbon was also shown to effectively remove biodegradable by-products and residual H2O2.

  13. Microgravity Processing of Oxide Superconductors

    NASA Technical Reports Server (NTRS)

    Olive, James R.; Hofmeister, William H.; Bayuzick, Robert J.; Vlasse, Marcus

    1999-01-01

    Considerable effort has been concentrated on the synthesis and characterization of high T(sub c) oxide superconducting materials. The YBaCuO system has received the most intense study, as this material has shown promise for the application of both thin film and bulk materials. There are many problems with the application of bulk materials- weak links, poor connectivity, small coherence length, oxygen content and control, environmental reactivity, phase stability, incongruent melting behavior, grain boundary contamination, brittle mechanical behavior, and flux creep. The extent to which these problems are intrinsic or associated with processing is the subject of controversy. This study seeks to understand solidification processing of these materials, and to use this knowledge for alternative processing strategies, which, at the very least, will improve the understanding of bulk material properties and deficiencies. In general, the phase diagram studies of the YBaCuO system have concentrated on solid state reactions and on the Y2BaCuO(x) + liquid yields YBa2Cu3O(7-delta) peritectic reaction. Little information is available on the complete melting relations, undercooling, and solidification behavior of these materials. In addition, rare earth substitutions such as Nd and Gd affect the liquidus and phase relations. These materials have promising applications, but lack of information on the high temperature phase relations has hampered research. In general, the understanding of undercooling and solidification of high temperature oxide systems lags behind the science of these phenomena in metallic systems. Therefore, this research investigates the fundamental melting relations, undercooling, and solidification behavior of oxide superconductors with an emphasis on improving ground based synthesis of these materials.

  14. Microgravity Processing of Oxide Superconductors

    NASA Technical Reports Server (NTRS)

    Hofmeister, William H.; Bayuzick, Robert J.; Vlasse, Marcus; McCallum, William; Peters, Palmer (Technical Monitor)

    2000-01-01

    The primary goal is to understand the microstructures which develop under the nonequilibrium solidification conditions achieved by melt processing in copper oxide superconductor systems. More specifically, to define the liquidus at the Y- 1:2:3 composition, the Nd-1:2:3 composition, and several intermediate partial substitution points between pure Y-1:2:3 and Nd-1:2:3. A secondary goal has been to understand resultant solidification morphologies and pathways under a variety of experimental conditions and to use this knowledge to better characterize solidification phenomena in these systems.

  15. On-the-Fly Kinetic Monte Carlo Simulation of Aqueous Phase Advanced Oxidation Processes.

    PubMed

    Guo, Xin; Minakata, Daisuke; Crittenden, John

    2015-08-04

    We have developed an on-the-fly kinetic Monte Carlo (KMC) model to predict the degradation mechanisms and fates of intermediates and byproducts that are produced during aqueous-phase advanced oxidation processes (AOPs). The on-the-fly KMC model is composed of a reaction pathway generator, a reaction rate constant estimator, a mechanistic reduction module, and a KMC solver. The novelty of this work is that we develop the pathway as we march forward in time rather than developing the pathway before we use the KMC method to solve the equations. As a result, we have fewer reactions to consider, and we have greater computational efficiency. We have verified this on-the-fly KMC model for the degradation of polyacrylamide (PAM) using UV light and titanium dioxide (i.e., UV/TiO2). Using the on-the-fly KMC model, we were able to predict the time-dependent profiles of the average molecular weight for PAM. The model provided detailed and quantitative insights into the time evolution of the molecular weight distribution and reaction mechanism. We also verified our on-the-fly KMC model for the destruction of (1) acetone, (2) trichloroethylene (TCE), and (3) polyethylene glycol (PEG) for the ultraviolet light and hydrogen peroxide AOP. We demonstrated that the on-the-fly KMC model can achieve the same accuracy as the computer-based first-principles KMC (CF-KMC) model, which has already been validated in our earlier work. The on-the-fly KMC is particularly suitable for molecules with large molecular weights (e.g., polymers) because the degradation mechanisms for large molecules can result in hundreds of thousands to even millions of reactions. The ordinary differential equations (ODEs) that describe the degradation pathways cannot be solved using traditional numerical methods, but the KMC can solve these equations.

  16. The chemistry side of AOP: implications for toxicity ...

    EPA Pesticide Factsheets

    An adverse outcome pathway (AOP) is a structured representation of the biological events that lead to adverse impacts following a molecular initiating event caused by chemical interaction with a macromolecule. AOPs have been proposed to facilitate toxicity extrapolation across species through understanding of species similarity in the sequence of molecular, cellular, organ and organismal level responses. However, AOPs are non-specific regarding the identity of the chemical initiators, and the range of structures for which an AOP is considered applicable has generally been poorly defined. Applicability domain has been widely understood in the field of QSAR as the response and chemical structure space in which the model makes predictions with a given reliability, and has been traditionally applied to define the similarity of query molecules within the training set. Three dimensional (3D) receptor modeling offers an approach to better define the applicability domain for selected AOPs through determination of the chemical space of the molecular initiating event. Universal 3D-QSAR models were developed for acetylcholinesterase inhibitors and estrogen receptor agonists and antagonists using a combination of fingerprint, molecular docking and structure-based pharmacophore approaches. The models were based on the critical molecular interactions within each receptor ligand binding domain, and included the key amino acid residues responsible for high binding affinity. T

  17. Quantitative AOP-based predictions for two aromatase ...

    EPA Pesticide Factsheets

    The adverse outcome pathway (AOP) framework can be used to support the use of mechanistic toxicology data as a basis for risk assessment. For certain risk contexts this includes defining, quantitative linkages between the molecular initiating event (MIE) and subsequent key events (KEs) within an AOP. One AOP for which strong, quantitative linkages have been established is aromatase inhibition leading to reproductive dysfunction in fish. A series of computational models have been linked to develop a quantitative AOP (Q-AOP). A measure of aromatase inhibition is used as the model input to estimate circulating plasma estradiol (E2) concentration and resultant circulating plasma vitellogenin (VTG) concentration. To evaluate model predictions, two aromatase inhibitors, letrozole and epoxiconazole, were selected based upon their relative aromatase inhibition potency in US EPA ToxCast assays. Reproductively mature female fathead minnows (Pimephales promelas) were exposed to varying concentrations of either letrozole (0.5, 7.5, 25, 75, 250 µg/L) or epoxiconazole (8, 25, 80, 250, 800 µg/L) in 24h flow through exposures. One additional consideration for model predictions was bioaccumulation of exposure chemicals and resultant circulating plasma concentration. To identify this, plasma from exposed minnows was extracted by supported liquid extraction (SLE) and concentrations of letrozole or epoxiconazole determined by LC-MS/MS. Plasma bioaccumulation factors (BAFplasma)

  18. 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.

    PubMed

    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

  19. Fluidized-bed copper oxide process

    SciTech Connect

    Shah, P.P.; Takahashi, G.S.; Leshock, D.G.

    1991-10-14

    The fluidized-bed copper oxide process was developed to simultaneously remove sulfur dioxide and nitrogen oxide contaminants from the flue gas of coal-fired utility boilers. This dry and regenerable process uses a copper oxide sorbent in a fluidized-bed reactor. Contaminants are removed without generating waste material. (VC)

  20. SULFATE RADICAL-BASED FERROUS-PEROXYMONOSULFATE OXIDATIVE SYSTEM FOR PCBs DEGRADATION IN AQUEOUS AND SEDIMENT SYSTEMS

    EPA Science Inventory

    Polychlorinated biphenyls (PCBs) in the environment pose long-term risk to public health because of their persistent and toxic nature. This study investigates the degradation of PCBs using sulfate radical-based advanced oxidation processes (SR-AOPs). These processes are based o...

  1. A comparative study among different photochemical oxidation processes to enhance the biodegradability of paper mill wastewater.

    PubMed

    Jamil, Tarek S; Ghaly, Montaser Y; El-Seesy, Ibrahim E; Souaya, Eglal R; Nasr, Rabab A

    2011-01-15

    Advanced oxidation processes including UV, UV/H(2)O(2), Fenton reaction (Fe(II)/H(2)O(2)) and photo-Fenton process (Fe(II)/H(2)O(2)/UV) for the treatment of paper mill wastewater will be investigated. A comparison among these techniques is undertaken with respect to the decrease of chemical oxygen demand (COD) and total suspended solids (TSS) and the evolution of chloride ions. Optimum operating conditions for each process under study revealed the effect of the initial amounts of Fe(II) and hydrogen peroxide. Of the tested processes, photo-Fenton process was found to be the fastest one with respect to COD and TSS reduction of the wastewater within 45 min reaction time under low amounts of Fe(II) and hydrogen peroxide of 0.5 and 1.5mg/L, respectively, and amounted to 79.6% and 96.6% COD and TSS removal. The initial biodegradability of the organic matter present in the effluent, estimated as the BOD(5)/COD, was low 0.21. When the effluent was submitted to the different types of AOPs used in this study, the biodegradability increases significantly. Within 45 min of reaction time, the photo-Fenton process appears as the most efficient process in the enhancement of the biodegradability of the organic matter in the effluent and the BOD(5)/COD ratio increased from 0.21 to 0.7.

  2. Advanced On-Board Processor (AOP). [for future spacecraft applications

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Advanced On-board Processor the (AOP) uses large scale integration throughout and is the most advanced space qualified computer of its class in existence today. It was designed to satisfy most spacecraft requirements which are anticipated over the next several years. The AOP design utilizes custom metallized multigate arrays (CMMA) which have been designed specifically for this computer. This approach provides the most efficient use of circuits, reduces volume, weight, assembly costs and provides for a significant increase in reliability by the significant reduction in conventional circuit interconnections. The required 69 CMMA packages are assembled on a single multilayer printed circuit board which together with associated connectors constitutes the complete AOP. This approach also reduces conventional interconnections thus further reducing weight, volume and assembly costs.

  3. Differential activation of CC chemokine receptors by AOP-RANTES.

    PubMed

    Elsner, J; Mack, M; Brühl, H; Dulkys, Y; Kimmig, D; Simmons, G; Clapham, P R; Schlöndorff, D; Kapp, A; Wells, T N; Proudfoot, A E

    2000-03-17

    RANTES (regulated on activation normal T cell expressed) has been found at elevated levels in biological fluids from patients with a wide range of allergic and autoimmune diseases and is able to attract several subtypes of leukocytes including eosinophils and monocytes into inflamed tissue. Amino-terminal modifications of RANTES produce receptor antagonists which are candidates for blocking this cellular recruitment. Met-RANTES has been shown to modulate inflammation in vivo, while AOP-RANTES is a potent inhibitor of R5 human immunodeficiency virus type 1 (HIV-1) strains and has been shown to down-modulate CCR5 and prevent recycling of the receptor. We have studied the effect of AOP-RANTES in eosinophil activation and have found that it is able to efficiently elicit eosinophil effector functions through CCR3, as measured by the release of reactive oxygen species and calcium mobilization, whereas Met-RANTES is inactive in these assays. AOP-RANTES is found to inhibit CCR3-mediated HIV-1 infection with moderate potency, in contrast to its potent inhibition of CCR5-mediated HIV-1 infection. Furthermore, we have investigated the abilities of these modified proteins to down-modulate CCR1 and CCR3 from the surface of monocytes and eosinophils. We show here that AOP-RANTES is much less effective than RANTES in down-modulation of CCR1. Surprisingly, recycling of CCR1 was minimal after incubation with RANTES while there was complete recycling with AOP-RANTES. In the case of CCR3, no significant difference was found between RANTES and AOP-RANTES in down-modulation and recycling. It therefore appears that trafficking of RANTES receptors follows different patterns, which opens up potential new targets for therapeutic intervention.

  4. Significant role of UV and carbonate radical on the degradation of oxytetracycline in UV-AOPs: Kinetics and mechanism.

    PubMed

    Liu, Yiqing; He, Xuexiang; Duan, Xiaodi; Fu, Yongsheng; Fatta-Kassinos, Despo; Dionysiou, Dionysios D

    2016-05-15

    Carbonate radical (CO3(•-)), a selective oxidant, reacts readily with electron-rich compounds through electron transfer and/or hydrogen abstraction. In this study, the role of CO3(•-) in degrading oxytetracycline (OTC) by UV only, UV/H2O2 and UV/persulfate (UV/PS) advanced oxidation processes (AOPs) in the presence of HCO3(-) or CO3(2-) was investigated. For UV only process, the presence of photosensitizers, i.e., nitrate (NO3(-)) and natural organic matter (NOM), had different impacts on OTC degradation, i.e., an enhancing effect by NO3(-) due to the generation of HO(•) and a slight inhibiting effect by NOM possibly due to a light scattering effect. Differently for UV/H2O2 and UV/PS processes, the presence of NO3(-) hardly influenced the destruction of OTC. Generation of CO3(•-) presented a positive role on OTC degradation by UV/NO3(-)/HCO3(-). Such influence was also observed in the two studied AOPs in the presence of both bicarbonate and other natural water constituents. When various natural water samples from different sources were used as reaction matrices, UV only and UV/H2O2 showed an inhibiting effect while UV/PS demonstrated a comparable or even promoting effect in OTC decomposition. After elucidating the potential contribution of UV direct photolysis via excited state OTC* at an elevated reaction pH condition, putative OTC transformation byproducts via CO3(•-) reaction were identified by ultra-high definition accurate-mass quadrupole time-of-flight tandem mass spectrometry (QTOF/MS). Five different reaction pathways were subsequently proposed, including hydroxylation (+16 Da), quinonization (+14 Da), demethylation (-14 Da), decarbonylation (-28 Da) and dehydration (-18 Da). The significant role of UV at high pH and CO3(•-) on OTC removal from contaminated water was therefore demonstrated both kinetically and mechanistically.

  5. An overview on the advanced oxidation processes applied for the treatment of water pollutants defined in the recently launched Directive 2013/39/EU.

    PubMed

    Ribeiro, Ana R; Nunes, Olga C; Pereira, Manuel F R; Silva, Adrián M T

    2015-02-01

    Environmental pollution is a recognized issue of major concern since a wide range of contaminants has been found in aquatic environment at ngL(-1) to μgL(-1) levels. In the year 2000, a strategy was defined to identify the priority substances concerning aquatic ecosystems, followed by the definition of environmental quality standards (EQS) in 2008. Recently it was launched the Directive 2013/39/EU that updates the water framework policy highlighting the need to develop new water treatment technologies to deal with such problem. This review summarizes the data published in the last decade regarding the application of advanced oxidation processes (AOPs) to treat priority compounds and certain other pollutants defined in this Directive, excluding the inorganic species (cadmium, lead, mercury, nickel and their derivatives). The Directive 2013/39/EU includes several pesticides (aldrin, dichlorodiphenyltrichloroethane, dicofol, dieldrin, endrin, endosulfan, isodrin, heptachlor, lindane, pentachlorophenol, chlorpyrifos, chlorfenvinphos, dichlorvos, atrazine, simazine, terbutryn, diuron, isoproturon, trifluralin, cypermethrin, alachlor), solvents (dichloromethane, dichloroethane, trichloromethane and carbon tetrachloride), perfluorooctane sulfonic acid and its derivatives (PFOS), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), nonylphenol and octylphenol, as well as the three compounds included in the recommendation for the first watch list of substances (diclofenac, 17-alpha-ethinylestradiol (EE2) and 17-beta-estradiol (E2)). Some particular pesticides (aclonifen, bifenox, cybutryne, quinoxyfen), organotin compounds (tributyltin), dioxins and dioxin-like compounds, brominated diphenylethers, hexabromocyclododecanes and di(2-ethylhexyl)phthalate are also defined in this Directive, but studies dealing with AOPs are missing. AOPs are recognized tools to destroy recalcitrant compounds or, at least, to transform them into biodegradable species

  6. Selecting the best AOP for isoxazolyl penicillins degradation as a function of water characteristics: Effects of pH, chemical nature of additives and pollutant concentration.

    PubMed

    Villegas-Guzman, Paola; Silva-Agredo, Javier; Florez, Oscar; Giraldo-Aguirre, Ana L; Pulgarin, Cesar; Torres-Palma, Ricardo A

    2017-04-01

    To provide new insights toward the selection of the most suitable AOP for isoxazolyl penicillins elimination, the degradation of dicloxacillin, a isoxazolyl penicillin model, was studied using different advanced oxidation processes (AOPs): ultrasound (US), photo-Fenton (UV/H2O2/Fe(2+)) and TiO2 photocatalysis (UV/TiO2). Although all processes achieved total removal of the antibiotic and antimicrobial activity, and increased the biodegradability level of the solutions, significant differences concerning the mineralization extend, the pH of the solution, the pollutant concentration and the chemical nature of additives were found. UV/TiO2 reached almost complete mineralization; while ∼10% mineralization was obtained for UV/H2O2/Fe(2+) and practically zero for US. Effect of initial pH, mineral natural water and the presence of organic (glucose, 2-propanol and oxalic acid) were then investigated. UV/H2O2/Fe(2+) and US processes were improved in acidic media, while natural pH favored UV/TiO2 system. According to both the nature of the added organic compound and the process, inhibition, no effect or enhancement of the degradation rate was observed. The degradation in natural mineral water showed contrasting results according to the antibiotic concentration: US process was enhanced at low concentration of dicloxacillin followed by detrimental effects at high substrate concentrations. A contrary effect was observed during photo-Fenton, while UV/TiO2 was inhibited in all of cases. Finally, a schema illustrating the enhancement or inhibiting effects of water matrix is proposed as a tool for selecting the best process for isoxazolyl penicillins degradation.

  7. The Use of Ultra-Violet (UV) Light Emitting Diodes (LEDS) in an Advanced Oxidation Process (AOP) with Brilliant Blue FCF as an Indicator

    DTIC Science & Technology

    2015-03-26

    indicated that it performed suitably as a witness dye with improved characteristics as compared to methylene blue. Further, the experiments indicated...light output by methylene blue adsorption on post experimentation reactor UV LEDsUV LED Quartz Lens Adsorption Experiment ...31 UV Brilliant Blue FCF...10 Figure 2 - Flow through reactor with UV LEDs

  8. Developing putative AOPs from high content dataDeveloping putative AOPs from high content dataDeveloping putative AOPs from high content dataDeveloping putative AOPs from high content data

    EPA Science Inventory

    Developing putative AOPs from high content data Shannon M. Bell1,2, Stephen W. Edwards2 1 Oak Ridge Institute for Science and Education 2 Integrated Systems Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development,...

  9. Surface water disinfection by chlorination and advanced oxidation processes: Inactivation of an antibiotic resistant E. coli strain and cytotoxicity evaluation.

    PubMed

    Miranda, Andreza Costa; Lepretti, Marilena; Rizzo, Luigi; Caputo, Ivana; Vaiano, Vincenzo; Sacco, Olga; Lopes, Wilton Silva; Sannino, Diana

    2016-06-01

    The release of antibiotics into the environment can result in antibiotic resistance (AR) spread, which in turn can seriously affect human health. Antibiotic resistant bacteria have been detected in different aquatic environments used as drinking water source. Water disinfection may be a possible solution to minimize AR spread but conventional processes, such as chlorination, result in the formation of dangerous disinfection by-products. In this study advanced oxidation processes (AOPs), namely H2O2/UV, TiO2/UV and N-TiO2/UV, have been compared with chlorination in the inactivation of an AR Escherichia coli (E. coli) strain in surface water. TiO2 P25 and nitrogen doped TiO2 (N-TiO2), prepared by sol-gel method at two different synthesis temperatures (0 and -20°C), were investigated in heterogeneous photocatalysis experiments. Under the investigated conditions, chlorination (1.0 mg L(-1)) was the faster process (2.5 min) to achieve total inactivation (6 Log). Among AOPs, H2O2/UV resulted in the best inactivation rate: total inactivation (6 Log) was achieved in 45 min treatment. Total inactivation was not observed (4.5 Log), also after 120 min treatment, only for N-doped TiO2 synthesized at 0°C. Moreover, H2O2/UV and chlorination processes were evaluated in terms of cytotoxicity potential by means of 3-(4,5-dime-thylthiazol-2-yl)-2,5-diphenylte-trazolium colorimetric test on a human-derived cell line and they similarly affected HepG2 cells viability.

  10. An evaluation of the use of an advanced oxidation process to remove chlorinated hydrocarbons from groundwater at the US Department of Energy Kansas City Plant

    SciTech Connect

    Garland, S.B. II; Peyton, G.R.

    1990-10-01

    The Allied-Signal Aerospace Company currently operates a production facility in Kansas City, Missouri, under contract with the US Department of Energy (DOE). Over the years the operation of the DOE Kansas City Plant has resulted in the contamination of groundwater with chlorinated hydrocarbons, including trichloroethene (TCE). One of the plumes of contaminated groundwater, the underground tank farm (UTF) plume, was selected for remediation with an advanced oxidation process (AOP) consisting of simultaneous treatment by ozone (O{sub 3}), ultraviolet (UV) radiation, and hydrogen peroxide (H{sub 2}O{sub 2}). Since the use of AOPs is relatively new for the removal of organics from groundwater, information on design criteria, costs, performance, and operating experience is not well documented in the literature. Therefore, the Oak Ridge National Laboratory (ORNL) was requested to evaluate the treatment process. This report documents the work performed through FY 1989. The results of the initial year of the evaluations, FY 1988, have been published previously, and the evaluation will continue at least through FY 1990. This report first briefly describes the treatment plant and the mechanisms of the treatment process. Next, the methodology and the results from the evaluation are discussed. Finally, conclusions and recommendations are presented. 8 refs., 14 figs., 16 tabs.

  11. PROCESSES OF CHLORINATION OF URANIUM OXIDES

    DOEpatents

    Rosenfeld, S.

    1958-09-16

    An improvement is described in the process fur making UCl/sub 4/ from uranium oxide and carbon tetrachloride. In that process, oxides of uranium are contacted with carbon tetrachloride vapor at an elevated temperature. It has been fuund that the reaction product and yield are improved if the uranlum oxide charge is disposed in flat trays in the reaction zone, to a depth of not more than 1/2 centimeter.

  12. Accelerated oxidation processes is biodiesel

    SciTech Connect

    Canakci, M.; Monyem, A.; Van Gerpen, J.

    1999-12-01

    Biodiesel is an alternative fuel for diesel engines that can be produced from renewable feedstocks such as vegetable oil and animal fats. These feedstocks are reacted with an alcohol to produce alkyl monoesters that can be used in conventional diesel engines with little or no modification. Biodiesel, especially if produced from highly unsaturated oils, oxidizes more rapidly than diesel fuel. This article reports the results of experiments to track the chemical and physical changes that occur in biodiesel as it oxidizes. These results show the impact of time, oxygen flow rate, temperature, metals, and feedstock type on the rate of oxidation. Blending with diesel fuel and the addition of antioxidants are explored also. The data indicate that without antioxidants, biodiesel will oxidize very quickly at temperatures typical of diesel engines. This oxidation results in increases in peroxide value, acid value, and viscosity. While the peroxide value generally reaches a plateau of about 350 meq/kg ester, the acid value and viscosity increase monotonically as oxidation proceeds.

  13. Insights into real cotton-textile dyeing wastewater treatment using solar advanced oxidation processes.

    PubMed

    Soares, Petrick A; Silva, Tânia F C V; Manenti, Diego R; Souza, Selene M A G U; Boaventura, Rui A R; Vilar, Vítor J P

    2014-01-01

    Different advanced oxidation processes (AOPs) were applied to the treatment of a real cotton-textile dyeing wastewater as a pre-oxidation step to enhance the biodegradability of the recalcitrant compounds, which can be further oxidized using a biological process. Tests were conducted on a lab-scale prototype using artificial solar radiation and at pilot scale with compound parabolic collectors using natural solar radiation. The cotton-textile dyeing wastewater presents a lilac color, with a maximum absorbance peak at 641 nm, alkaline pH (pH = 8.2), moderate organic content (DOC = 152 mg C L(-1), COD = 684 mg O2 L(-1)) and low-moderate biodegradability (40 % after 28 days in Zahn-Wellens test). All the tested processes contributed to an effective decolorization and mineralization, but the most efficient process was the solar-photo-Fenton with an optimum catalyst concentration of 60 mg Fe(2+) L(-1), leading to 98.5% decolorization and 85.5% mineralization after less than 0.1 and 5.8 kJUV L(-1), respectively. In order to achieve a final wastewater with a COD below 250 mg O2 L(-1) (discharge limit into water bodies imposed by the Portuguese Legislation-Portaria no. 423/97 of 25 June 1997), considering the combination of a solar-photo-Fenton reaction with a biological process, the phototreatment energy required is 0.5 kJUV L(-1), consuming 7.5 mM hydrogen peroxide, resulting in 58.4% of mineralization [Formula: see text].

  14. Plutonium Oxide Process Capability Work Plan

    SciTech Connect

    Meier, David E.; Tingey, Joel M.

    2014-02-28

    Pacific Northwest National Laboratory (PNNL) has been tasked to develop a Pilot-scale Plutonium-oxide Processing Unit (P3U) providing a flexible capability to produce 200g (Pu basis) samples of plutonium oxide using different chemical processes for use in identifying and validating nuclear forensics signatures associated with plutonium production. Materials produced can also be used as exercise and reference materials.

  15. The potential of AOP networks for reproductive and developmental toxicity assay development.

    PubMed

    Knapen, Dries; Vergauwen, Lucia; Villeneuve, Daniel L; Ankley, Gerald T

    2015-08-15

    Historically, the prediction of reproductive and developmental toxicity has largely relied on the use of animals. The adverse outcome pathway (AOP) framework forms a basis for the development of new non-animal test methods. It also provides biological context for mechanistic information from existing assays. However, a single AOP may not capture all events that contribute to any relevant toxic effect, even in single chemical exposure scenarios. AOP networks, defined as sets of AOPs sharing at least one common element, are capable of more realistically representing potential chemical effects. They provide information on interactions between AOPs and have the potential to reveal previously unknown links between biological pathways. Analysis of these AOP networks can aid the prioritization of assay development, whether the goal is to develop a single assay with predictive utility of multiple outcomes, or development of assays that are highly specific for a particular mode of action. This paper provides a brief overview of the AOPs related to reproductive and developmental toxicity currently available in the AOP Wiki (http://aopwiki.org), and gives an example of an AOP network based on five reproductive and developmental toxicity-related AOPs for fish to illustrate how AOP networks can be used for assay development and refinement.

  16. Computer-based first-principles kinetic modeling of degradation pathways and byproduct fates in aqueous-phase advanced oxidation processes.

    PubMed

    Guo, Xin; Minakata, Daisuke; Niu, Junfeng; Crittenden, John

    2014-05-20

    In this study, a computer-based first-principles kinetic model is developed to predict the degradation mechanisms and fates of intermediates and byproducts produced during aqueous-phase advanced oxidation processes (AOPs) for various organic compounds. The model contains a rule-based pathway generator to generate the reaction pathways, a reaction rate constant estimator to estimate the reaction rate constant for each reaction generated, a mechanistic reduction module to reduce the generated mechanisms, an ordinary differential equations generator and solver to solve the generated mechanisms and calculate the concentration profiles for all species, and a toxicity estimator to estimate the toxicity of major species and calculate time-dependent profiles of relative toxicity (i.e., concentration of species divided by toxicity value). We predict concentration profiles of acetone and trichloroethylene and their intermediates and byproducts in photolysis with hydrogen peroxide (i.e., UV/H2O2) and validate with experimental observations. The predicted concentration profiles for both parent compounds are consistent with experimental data. The calculated profiles of 96-h green algae chronic toxicity show that the overall toxicity decreases during the degradation process. These generated mechanisms also provide detailed and quantitative insights into the pathways for the formation and consumption of important intermediates and byproducts produced during AOPs. Our approach is sufficiently general to be applied to a wide range of contaminants.

  17. Comparison of UV/hydrogen peroxide and UV/peroxydisulfate processes for the degradation of humic acid in the presence of halide ions.

    PubMed

    Lou, Xiaoyi; Xiao, Dongxue; Fang, Changling; Wang, Zhaohui; Liu, Jianshe; Guo, Yaoguang; Lu, Shuyu

    2016-03-01

    This study compared the behaviors of two classic advanced oxidation processes (AOPs), hydroxyl radical-based AOPs ((•)OH-based AOPs) and sulfate radical-based AOPs (SO4 (•-)-based AOPs), represented by UV/ hydrogen peroxide (H2O2) and UV/peroxydisulfate (PDS) systems, respectively, to degrade humic acid (HA) in the presence of halide ions (Cl(-) and Br(-)). The effects of different operational parameters, such as oxidant dosages, halide ions concentration, and pH on HA degradation were investigated in UV/H2O2/Cl(-), UV/PDS/Cl(-), UV/H2O2/Br(-), and UV/PDS/Br(-) processes. It was found that the oxidation capacity of H2O2 and PDS to HA degradation in the presence of halides was nearly in the same order. High dosage of peroxides would lead to an increase in HA removal while excess dosage would slightly inhibit the efficiency. Both Cl(-) and Br(-) would have depressing impact on the two AOPs, but the inhibiting effect of Br(-) was more obvious than that of Cl(-), even the concentration of Cl(-) was far above that of Br(-). The increasing pH would have an adverse effect on HA decomposition in UV/H2O2 system, whereas there was no significant impact of pH in UV/PDS process. Furthermore, infrared spectrometer was used to provide the information of degraded HA in UV/H2O2/Cl(-), UV/PDS/Cl(-), UV/H2O2/Br(-), and UV/PDS/Br(-) processes, and halogenated byproducts were identified in using GC-MS analysis in the four processes. The present research might have significant technical implications on water treatment using advanced oxidation technologies.

  18. Mechanisms of lung fibrosis induced by carbon nanotubes: towards an Adverse Outcome Pathway (AOP).

    PubMed

    Vietti, Giulia; Lison, Dominique; van den Brule, Sybille

    2016-02-29

    Several experimental studies have shown that carbon nanotubes (CNT) can induce respiratory effects, including lung fibrosis. The cellular and molecular events through which these effects develop are, however, not clearly elucidated. The purpose of the present review was to analyze the key events involved in the lung fibrotic reaction induced by CNT and to assess their relationships. We thus address current knowledge and gaps with a view to draft an Adverse Outcome Pathway (AOP) concerning the fibrotic potential of CNT.As for many inhaled particles, CNT can indirectly activate fibroblasts through the release of pro-inflammatory (IL-1β) and pro-fibrotic (PDGF and TGF-β) mediators by inflammatory cells (macrophages and epithelial cells) via the induction of oxidative stress, inflammasome or NF-kB. We also highlight here direct effects of CNT on fibroblasts, which appear as a new mode of toxicity relatively specific for CNT. Direct effects of CNT on fibroblasts include the induction of fibroblast proliferation, differentiation and collagen production via ERK 1/2 or Smad signaling. We also point out the physico-chemical properties of CNT important for their toxicity and the relationship between in vitro and in vivo effects. This knowledge provides evidence to draft an AOP for the fibrogenic activity of CNT, which allows developing simple in vitro models contributing to predict the CNT effects in lung fibrosis, and risk assessment tools for regulatory decision.

  19. Conventional and advanced oxidation processes used in disinfection of treated urban wastewater.

    PubMed

    Rodríguez-Chueca, J; Ormad, M P; Mosteo, R; Sarasa, J; Ovelleiro, J L

    2015-03-01

    The purpose of the current study is to compare the inactivation of Escherichia coli in wastewater effluents using conventional treatments (chlorination) and advanced oxidation processes (AOPs) such as UV irradiation, hydrogen peroxide (H2O2)/solar irradiation, and photo-Fenton processes. In addition, an analysis of the operational costs of each treatment is carried out taking into account the optimal dosages of chemicals used. Total inactivation of bacteria (7.5 log) was achieved by means of chlorination and UV irradiation. However, bacterial regrowth was observed 6 hours after the completion of UV treatment, obtaining a disinfection value around 3 to 4 log. On the other hand, the combination H2O2/solar irradiation achieved a maximum inactivation of E. coli of 3.30 ± 0.35 log. The photo-Fenton reaction achieved a level of inactivation of 4.87 ± 0.10 log. The order of disinfection, taking into account the reagent/cost ratio of each treatment, is as follows: chlorination > UV irradiation > photo-Fenton > H2O2/sunlight irradiation.

  20. Effect of matrix components on UV/H2O2 and UV/S2O8(2-) advanced oxidation processes for trace organic degradation in reverse osmosis brines from municipal wastewater reuse facilities.

    PubMed

    Yang, Yi; Pignatello, Joseph J; Ma, Jun; Mitch, William A

    2016-02-01

    When reverse osmosis brines from potable wastewater reuse plants are discharged to poorly-flushed estuaries, the concentrated organic contaminants are a concern for receiving water ecosystems. UV/hydrogen peroxide (UV/H2O2) and UV/persulfate (UV/S2O8(2-)) advanced oxidation processes (AOPs) may reduce contaminant burdens prior to discharge, but the effects of the high levels of halide, carbonate and effluent organic matter (EfOM) normally present in these brines are unclear. On the one hand, these substances may reduce process efficiency by scavenging reactive oxygen species (ROS), hydroxyl (OH) and sulfate (SO4(-) radicals. On the other, the daughter radicals generated by halide and carbonate scavenging may themselves degrade organics, offsetting the effect of ROS scavenging. UV/H2O2 and UV/S2O8(2-) AOPs were compared for degradation of five pharmaceuticals spiked into brines obtained from two reuse facilities and the RO influent from one of them. For UV/H2O2, EfOM scavenged ∼75% of the OH, reducing the degradation efficiency of the target contaminants to a similar extent; halide and carbonate scavenging and the reactivities of associated daughter radicals were less important. For UV/S2O8(2-), anions (mostly Cl(-)) scavenged ∼93% of the SO4(-). Because daughter radicals of Cl(-) contributed to contaminant degradation, the reduction in contaminant degradation efficiency was only ∼75-80%, with the reduction driven by daughter radical scavenging by EfOM. Conversion of SO4(-) to more selective halogen and carbonate radicals resulted in a wider range of degradation efficiencies among the contaminants. For both AOPs, 250 mJ/cm(2) average fluence achieved significant removal of four pharmaceuticals, with significantly better performance by UV/S2O8(2-) treatment for some constituents. Accounting for the lower brine flowrates, the energy output to achieve this fluence in brines is comparable to that often applied to RO permeates. However, much higher fluence was

  1. Processing of Mixed Oxide Superconductors

    DTIC Science & Technology

    1990-07-01

    UROUP SUB-GROUP High Temperature Superconductivity , critical current -- 7-- 0superconductor, ceramic, magnetism 20 ’ I 19. ABSTRACT (Continue on...large intragrain currents and small intergrain currents . Magnetic separation works well for YBCO in liquid nitrogen. The technique can certainly be...between the intergrain and intragrain currents and that the short coherence length of oxide superconductors is not the main problem. The closest

  2. Treatment of wastewater containing acid rose red dye by biologically aerated filter after chemical oxidation.

    PubMed

    Wang, X; Gu, X; Zhou, X; Wang, W; Lin, D

    2007-08-01

    Combined processes of pre-chemical oxidation and biological aerated filter (BAF) were used to treat wastewater containing non-biodegradable acid rose red dye. Advance oxidation processes (AOPs) of ozone and Fenton reagent were applied for pre-chemical oxidation, which reduced the degree of color and organic matter simultaneously increasing the biodegradability of the wastewater. The majority of the organic matter was removed by BAF. When using ozone as pre-chemical oxidation, the operation is simpler. The combined processes of AOPs, including ozone and Fenton reagent, followed by BAF reduced the color and chemical oxygen demand (COD) to less than 20 degrees and 40 mg l(-1), respectively from the influent concentration of about 4000 degree color and 300 mg l(-1) COD. The effluent water quality could meet the required standard for grey water reuses.

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

    PubMed

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

    2016-11-15

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

  4. A KINETIC MODEL FOR H2O2/UV PROCESS IN A COMPLETELY MIXED BATCH REACTOR. (R825370C076)

    EPA Science Inventory

    A dynamic kinetic model for the advanced oxidation process (AOP) using hydrogen peroxide and ultraviolet irradiation (H2O2/UV) in a completely mixed batch reactor (CMBR) is developed. The model includes the known elementary chemical and photochemical reac...

  5. Degradation Mechanism of Cyanobacterial Toxin Cylindrospermopsin by Hydroxyl Radicals in Homogeneous UV/H2O2 Process

    EPA Science Inventory

    The degradation of cylindrospermopsin (CYN), a widely distributed and highly toxic cyanobacterial toxin (cyanotoxin), remains poorly elucidated. In this study, the mechanism of CYN destruction by UV-254 nm/H2O2 advanced oxidation process (AOP) was investigated by mass spectrometr...

  6. Energy efficient--advanced oxidation process for treatment of cyanide containing automobile industry wastewater.

    PubMed

    Mudliar, R; Umare, S S; Ramteke, D S; Wate, S R

    2009-05-30

    Destruction of cyanide (CN) from an automobile industry wastewater by advance oxidation process (AOP) has been evaluated. The operating conditions (in an indigenously designed photoreactor) for three different treatment strategies have been optimized. The treatment strategies involved use of, ultra violet light (UV), hydrogen peroxide (H(2)O(2)) and ozone (O(3)) in various combinations. Treatment of automobile industry wastewater (250 mg/L CN) showed fastest CN destruction, which was significantly (P<0.05) faster than that observed with synthetic wastewater (with similar CN concentration). A combined application of H(2)O(2)/O(3) was found to be the best option for maximum CN destruction. This treatment allows CN to reach the regional/international limit (of 0.02 mg/L) for safe industrial wastewater discharges to the receiving water bodies. The specific energy consumption by the photoreactor following this treatment was comparable to that obtained by conventional treatments, which use photocatalyst. Since the present treatment does not use catalyst, it provides an excellent energy efficient and economical option for treatment and safe disposal of CN containing industrial wastewater.

  7. Process for catalytically oxidizing cycloolefins, particularly cyclohexene

    DOEpatents

    Mizuno, Noritaka; Lyon, David K.; Finke, Richard G.

    1993-01-01

    This invention is a process for catalytically oxidizing cycloolefins, particularly cyclohexenes, to form a variety of oxygenates. The catalyst used in the process is a covalently bonded iridium-heteropolyanion species. The process uses the catalyst in conjunction with a gaseous oxygen containing gas to form 2-cyclohexen-1-ol and also 2-cyclohexen-1-one.

  8. Microwave processing of ceramic oxide filaments

    SciTech Connect

    Vogt, G.J.; Katz, J.D.

    1995-05-01

    The objective of the microwave filament processing project is to develop microwave techniques at 2.45 GHZ to manufacture continuous ceramic oxide filaments. Microwave processing uses the volumetric absorption of microwave power in oxide filament tows to drive off process solvents, to burn out organic binders, and to sinter the dried fibers to produce flexible, high-strength ceramic filaments. The technical goal is to advance filament processing technology by microwave heating more rapidly with less energy and at a lower cost than conventional processing, but with the same quality as conventional processing. The manufacturing goal is to collaborate with the 3M Company, a US manufacturer of ceramic oxide filaments, to evaluate the technology using a prototype filament system and to transfer the microwave technology to the 3M Company.

  9. The application of advanced oxidation technologies to the treatment of effluents from the pulp and paper industry: a review.

    PubMed

    Hermosilla, Daphne; Merayo, Noemí; Gascó, Antonio; Blanco, Ángeles

    2015-01-01

    The paper industry is adopting zero liquid effluent technologies to reduce freshwater use and meet environmental regulations, which implies closure of water circuits and the progressive accumulation of pollutants that must be removed before water reuse and final wastewater discharge. The traditional water treatment technologies that are used in paper mills (such as dissolved air flotation or biological treatment) are not able to remove recalcitrant contaminants. Therefore, advanced water treatment technologies, such as advanced oxidation processes (AOPs), are being included in industrial wastewater treatment chains aiming to either improve water biodegradability or its final quality. A comprehensive review of the current state of the art regarding the use of AOPs for the treatment of the organic load of effluents from the paper industry is herein addressed considering mature and emerging treatments for a sustainable water use in this sector. Wastewater composition, which is highly dependent on the raw materials being used in the mills, the selected AOP itself, and its combination with other technologies, will determine the viability of the treatment. In general, all AOPs have been reported to achieve good organic removal efficiencies (COD removal >40%, and about an extra 20% if AOPs are combined with biological stages). Particularly, ozonation has been the most extensively reported and successfully implemented AOP at an industrial scale for effluent treatment or reuse within pulp and paper mills, although Fenton processes (photo-Fenton particularly) have actually addressed better oxidative results (COD removal ≈ 65-75%) at a lab scale, but still need further development at a large scale.

  10. Oxidation of organics in retentates from reverse osmosis wastewater reuse facilities.

    PubMed

    Westerhoff, Paul; Moon, Hye; Minakata, Daisuke; Crittenden, John

    2009-09-01

    The use of membrane processes for wastewater treatment and reuse is rapidly expanding. Organic, inorganic, and biological constituents are effectively removed by reverse osmosis (RO) membrane processes, but concentrate in membrane retentates Disposal of membrane concentrates is a growing concern. Applying advanced oxidation processes (AOPs) to RO retentate is logical because extensive treatment and energy inputs were expended to concentrate the organics, and it is cheaper to treat smaller flowstreams. AOPs (e.g., UV irradiation in the presence of titanium dioxide; UV/TiO(2)) can remove a high percentage of organic matter from RO retentates. The combination of AOPs and a simple biological system (e.g., sand filter) can remove higher levels of organic matter at lower UV dosages because AOPs produce biologically degradable material (e.g., organic acids) that have low hydroxyl radical rate constants, meaning that their oxidation, rather than that of the primary organic matter in the RO retentate, dictates the required UV energy inputs. At the highest applied UV dose (10 kWh m(-)3), the dissolved organic carbon (DOC) in the RO retentate decreased from approximately 40 to 8 mg L(-)1, of which approximately 6 mg L(-)1 were readily biologically degradable. Therefore, after combined UV treatment and biodegradation, the final DOC concentration was 2 mg L(-)1, representing a 91% removal. These results suggest that UV/TiO(2) plus biodegradation of RO retentates is feasible and would significantly reduce the organic pollutant loading into the environment from wastewater reuse facilities.

  11. Process for removing sulfur oxide and nitrogen oxide

    SciTech Connect

    Bhattacharyya, A

    1989-05-16

    This patent describes a process for reducing at least one of (1) the sulfur oxide content of a sulfur oxide-containing gas and (2) the nitrogen oxide content of a nitrogen oxide-containing gs which includes contacting the gas with a material at conditions to reduce at least one of (1) the sulfur oxide content of the gas and (2) the nitrogen oxide of the gas, the improvement comprising utilizing as at least a portion of the material the spinel/clay composition produced in accordance with the process comprising: (a) combining (1) an acidic, aluminum-containing composition in which the aluminum is present in a positively charged species, and (2) a basic alkaline earth metal-containing composition to form a gel mixture; and (b) mixing the gel with kaolin clay to form a co-gel mixture; and (c) calcinating the co-gel mixture to form the alkaline earth metal, aluminum-containing spinel composition, in a kaolin clay matrix.

  12. Effect of halide ions and carbonates on organic contaminant degradation by hydroxyl radical-based advanced oxidation processes in saline waters.

    PubMed

    Grebel, Janel E; Pignatello, Joseph J; Mitch, William A

    2010-09-01

    Advanced oxidation processes (AOPs) generating nonselective hydroxyl radicals (HO*) provide a broad-spectrum contaminant destruction option for the decontamination of waters. Halide ions are scavengers of HO* during AOP treatment, such that treatment of saline waters would be anticipated to be ineffective. However, HO* scavenging by halides converts HO* to radical reactive halogen species (RHS) that participate in contaminant destruction but react more selectively with electron-rich organic compounds. The effects of Cl-, Br-, and carbonates (H2CO3+HCO3-+CO3(2-)) on the UV/H2O2 treatment of model compounds in saline waters were evaluated. For single target organic contaminants, the impact of these constituents on contaminant destruction rate suppression at circumneutral pH followed the order Br->carbonates>Cl-. Traces of Br- in the NaCl stock had a greater effect than Cl- itself. Kinetic modeling of phenol destruction demonstrated that RHS contributed significantly to phenol destruction, mitigating the impact of HO* scavenging. The extent of treatment efficiency reduction in the presence of halides varied dramatically among different target organic compounds. Destruction of contaminants containing electron-poor reaction centers in seawater was nearly halted, while 17beta-estradiol removal declined by only 3%. Treatment of mixtures of contaminants with each other and with natural organic matter (NOM) was evaluated. Although NOM served as an oxidant scavenger, conversion of nonselective HO* to selective radicals due to the presence of anions enhanced the efficiency of electron-rich contaminant removal in saline waters by focusing the oxidizing power of the system away from the NOM toward the target contaminant. Despite the importance of contaminant oxidation by halogen radicals, the formation of halogenated byproducts was minimal.

  13. Decolouration of H2SO4 leachate from phosphorus-saturated alum sludge using H2O2 and advanced oxidation processes in phosphorus recovery strategy.

    PubMed

    Zhao, X H; Zhao, Y Q

    2009-12-01

    As a part of attempt for phosphorus (P) recovery from P-saturated alum sludge, which was used as a low-cost P-adsorbent in treatment reed bed for wastewater treatment, decolouration of H(2)SO(4) leachate obtained from previous experiment, possessing a great deal of P, aluminum and red-brown coloured materials (RBCMs), by using H(2)O(2) and advanced oxidation processes (AOPs) was investigated. The use of H(2)O(2) and AOPs in the forms of Fenton (H(2)O(2)/Fe(2 +)) and photo-Fenton (UV/H(2)O(2)/Fe(2 +)) were tested. The changes in colour and total organic carbon (TOC) were taken place as a result of mineralization of RBCMs. The results revealed that all of these three processes examined were efficient. It was found that about 98% colour and 47% TOC can be removed under photo-Fenton treatment after 8 hours of UV irradiation.Correspondingly, the reaction rates of H(2)O(2) and Fenton systems were slow, but 100% colour and 59% TOC removal of H(2)O(2) process and 100% colour and 67% TOC reductions of Fenton process can be achieved after 72 hours of reaction. The changes of structure and molecular weight/size of RBCMs were also evaluated by HPLC and UV-vis spectroscopic analysis. From the results, some chromophores of RBCMs such as aromatic groups were appeared to be easily degraded to the smaller refractory components. Hence, based on the experimental results and considering the investment and expediency of operation, H(2)O(2) and Fenton oxidation could be suitable technologies for the treatment of the RBCMs derived from P-extraction stage by using H(2)SO(4) leaching.

  14. Reduction of metal oxides through mechanochemical processing

    DOEpatents

    Froes, Francis H.; Eranezhuth, Baburaj G.; Senkov, Oleg N.

    2000-01-01

    The low temperature reduction of a metal oxide using mechanochemical processing techniques. The reduction reactions are induced mechanically by milling the reactants. In one embodiment of the invention, titanium oxide TiO.sub.2 is milled with CaH.sub.2 to produce TiH.sub.2. Low temperature heat treating, in the range of 400.degree. C. to 700.degree. C., can be used to remove the hydrogen in the titanium hydride.

  15. Process for etching mixed metal oxides

    DOEpatents

    Ashby, C.I.H.; Ginley, D.S.

    1994-10-18

    An etching process is described using dicarboxylic and tricarboxylic acids as chelating etchants for mixed metal oxide films such as high temperature superconductors and ferroelectric materials. Undesirable differential etching rates between different metal oxides are avoided by selection of the proper acid or combination of acids. Feature sizes below one micron, excellent quality vertical edges, and film thicknesses in the 100 Angstrom range may be achieved by this method. 1 fig.

  16. Process for etching mixed metal oxides

    DOEpatents

    Ashby, Carol I. H.; Ginley, David S.

    1994-01-01

    An etching process using dicarboxylic and tricarboxylic acids as chelating etchants for mixed metal oxide films such as high temperature superconductors and ferroelectric materials. Undesirable differential etching rates between different metal oxides are avoided by selection of the proper acid or combination of acids. Feature sizes below one micron, excellent quality vertical edges, and film thicknesses in the 100 Angstom range may be achieved by this method.

  17. Hydrothermal processing of cellulose: A comparison between oxidative and non-oxidative processes.

    PubMed

    Yousefifar, Azadeh; Baroutian, Saeid; Farid, Mohammed M; Gapes, Daniel J; Young, Brent R

    2017-02-01

    This study investigates oxidative and non-oxidative hydrothermal processing of cellulose at five different temperatures (180-260°C). Volatile fatty acids (VFAs) concentration, total suspended solid (TSS) degradation, dissolved organic carbon (DOC) and chemical oxygen demand (COD) were measured and compared in both processes. Moreover, the existence of hydrogen peroxide in both oxidative and non-oxidative processes was confirmed experimentally for the first time in literature. At temperatures ⩽220°C the amount of H2O2 produced in the oxidative process was higher (50 fold) than that of in the non-oxidative while at higher temperatures (⩾240°C) it was more for non-oxidative (3.5-5 fold). The concentration of VFAs in the non-oxidative process was lower than 10% of that in oxidative process. In both processes soluble COD increased with time and temperature, however at 260°C after reaching a maximum, it decreased with time due to conversion of some soluble intermediates to CO2 and water.

  18. Degradation of endocrine disrupting chemicals bisphenol A, ethinyl estradiol, and estradiol during UV photolysis and advanced oxidation processes.

    PubMed

    Rosenfeldt, Erik J; Linden, Karl G

    2004-10-15

    The degradation of three endocrine disrupting chemicals (EDCs), bisphenol A, ethinyl estradiol, and estradiol, was investigated via ultraviolet (UV) radiation photolysis and the UV/hydrogen peroxide advanced oxidation process (AOP). These EDCs have been detected at low levels in wastewaters and surface waters in both the United States and European countries, can cause adverse effects on humans and wildlife via interactions with the endocrine system, and thus must be treated before entering the public drinking water supply. Because many EDCs can only be partially removed with conventional water treatment systems, there is a need to evaluate alternative treatment processes. For each EDC tested, direct UV photolysis quantum yields were derived for use with both monochromatic low-pressure (LP) UV lamps and polychromatic medium-pressure (MP) UV lamps and second-order hydroxyl radical rate constants were developed. These parameters were utilized to successfully model UV treatment of the EDCs in laboratory and natural waters. The polychromatic MP UV radiation source was more effective for direct photolysis degradation as compared to conventional LP UV lamps emitting monochromatic UV 254 nm radiation. However, in all cases the EDCs were more effectively degraded utilizing UV/H2O2 advanced oxidation as compared to direct UV photolysis treatment.

  19. Biodegradability of iopromide products after UV/H₂O₂ advanced oxidation.

    PubMed

    Keen, Olya S; Love, Nancy G; Aga, Diana S; Linden, Karl G

    2016-02-01

    Iopromide is an X-ray and MRI contrast agent that is virtually non-biodegradable and persistent through typical wastewater treatment processes. This study determined whether molecular transformation of iopromide in a UV/H2O2 advanced oxidation process (AOP) can result in biodegradable products. The experiments used iopromide labeled with carbon-14 on the aromatic ring to trace degradation of iopromide through UV/H2O2 advanced oxidation and subsequent biodegradation. The biotransformation assay tracked the formation of radiolabeled (14)CO2 which indicated full mineralization of the molecule. The results indicated that AOP formed biodegradable iopromide products. There was no (14)C released from the pre-AOP samples, but up to 20% of all radiolabeled carbon transformed into (14)CO2 over the course of 42 days of biodegradation after iopromide was exposed to advanced oxidation (compared to 10% transformation in inactivated post-AOP controls). In addition, the quantum yield of photolysis of iopromide was determined using low pressure (LP) and medium pressure (MP) mercury lamps as 0.069 ± 0.005 and 0.080 ± 0.007 respectively. The difference in the quantum yields for the two UV sources was not statistically significant at the 95% confidence interval (p = 0.08), which indicates the equivalency of using LP or MP UV sources for iopromide treatment. The reaction rate between iopromide and hydroxyl radicals was measured to be (2.5 ± 0.2) × 10(9) M(-1) s(-1). These results indicate that direct photolysis is a dominant degradation pathway in UV/H2O2 AOP treatment of iopromide. Other iodinated contrast media may also become biodegradable after exposure to UV or UV/H2O2.

  20. Advanced oxidation degradation kinetics as a function of ultraviolet LED duty cycle.

    PubMed

    Duckworth, Kelsey; Spencer, Michael; Bates, Christopher; Miller, Michael E; Almquist, Catherine; Grimaila, Michael; Magnuson, Matthew; Willison, Stuart; Phillips, Rebecca; Racz, LeeAnn

    2015-01-01

    Ultraviolet (UV) light emitting diodes (LEDs) may be a viable option as a UV light source for advanced oxidation processes (AOPs) utilizing photocatalysts or oxidizing agents such as hydrogen peroxide. The effect of UV-LED duty cycle, expressed as the percentage of time the LED is powered, was investigated in an AOP with hydrogen peroxide, using methylene blue (MB) to assess contaminant degradation. The UV-LED AOP degraded the MB at all duty cycles. However, adsorption of MB onto the LED emitting surface caused a linear decline in reactor performance over time. With regard to the effect of duty cycle, the observed rate constant of MB degradation, after being adjusted to account for the duty cycle, was greater for 5 and 10% duty cycles than higher duty cycles, providing a value approximately 160% higher at 5% duty cycle than continuous operation. This increase in adjusted rate constant at low duty cycles, as well as contaminant fouling of the LED surface, may impact design and operational considerations for pulsed UV-LED AOP systems.

  1. Comparison among the methods for hydrogen peroxide measurements to evaluate advanced oxidation processes: Application of a spectrophotometric method using copper(II) ion and 2,9-dimethyl-1,10-phenanthroline

    SciTech Connect

    Kosaka, Koji; Yamada, Harumi; Matsui, Saburo; Echigo, Shinya; Shishida, Kenichi

    1998-12-01

    Hydrogen peroxide (H{sub 2}O{sub 2}) in the range of several tens to several hundreds of micromoles per liter is usually added to the process water in advanced oxidation processes (AOPs). In this study, a spectrophotometric method using copper(II) ion and 2,9-dimethyl-1, 10-phenanthroline (DMP) for measuring H{sub 2}O{sub 2} concentration was compared with other methods [i.e., spectrophotometric methods using titanium oxalate and N,N-diethyl-p-phenylenediamine (DPD) and a fluorometric method using p-hydroxyphenyl acetic acid (POHPAA)]. Particular attention was paid to sensitivities and effects of coexisting substances. The most sensitive method was the fluorometric method, followed in order by DPD, DMP, and the titanium oxalate colorimetric method; their detection limits in 1-cm cells were 0.16, 0.77, 0.80, and 29 {micro}M, respectively. Therefore, the DMP method was found to be reasonably sensitive when applied to AOPs. In the DMP method, copper(II)-DMP complexes react with humic acid, and colored chemicals are produced. However, the slopes of the calibration curves of H{sub 2}O{sub 2} containing up to 10 mg of C L{sup {minus}1} from humic acid did not change significantly as compared to that in ultrapure water. The effect of chlorine on the DMP method was not observed up to at least 23 {micro}M (0.8 mg of Cl L{sup {minus}1}) of free chlorine, although the DPD and fluorometric methods are known to be interfered by chlorine. From this study, it was concluded that the DMP method is suitable to be used in AOPs.

  2. HANDBOOK ON ADVANCED PHOTOCHEMICAL OXIDATION PROCESSES

    EPA Science Inventory

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

  3. HANDBOOK ON ADVANCED NONPHOTOCHEMICAL OXIDATION PROCESSES

    EPA Science Inventory

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

  4. Process for preparing active oxide powders

    DOEpatents

    Berard, Michael F.; Hunter, Jr., Orville; Shiers, Loren E.; Dole, Stephen L.; Scheidecker, Ralph W.

    1979-02-20

    An improved process for preparing active oxide powders in which cation hydroxide gels, prepared in the conventional manner are chemically dried by alternately washing the gels with a liquid organic compound having polar characteristics and a liquid organic compound having nonpolar characteristics until the mechanical water is removed from the gel. The water-free cation hydroxide is then contacted with a final liquid organic wash to remove the previous organic wash and speed drying. The dried hydroxide treated in the conventional manner will form a highly sinterable active oxide powder.

  5. UV-based advanced oxidation processes for the treatment of odour compounds: efficiency and by-product formation.

    PubMed

    Zoschke, Kristin; Dietrich, Norman; Börnick, Hilmar; Worch, Eckhard

    2012-10-15

    The occurrence of the taste and odour compounds geosmin and 2-methyl isoborneol (2-MIB) affects the organoleptic quality of raw waters from drinking water reservoirs worldwide. UV-based oxidation processes for the removal of these substances are an alternative to adsorption and biological processes, since they additionally provide disinfection of the raw water. We could show that the concentration of geosmin and 2-MIB could be reduced by VUV irradiation and the combination of UV irradiation with ozone and hydrogen peroxide in pure water and water from a drinking water reservoir. The figure of merit EE/O is an appropriate tool to compare the AOPs and showed that VUV and UV/O(3) yielded the lowest treatment costs for the odour compounds in pure and raw water, respectively. Additionally, VUV irradiation with addition of ozone, generated by the VUV lamp, was evaluated. The generation of ozone and the irradiation were performed in a single reactor system using the same low-pressure mercury lamp, thereby reducing the energy consumption of the treatment process. The formation of the undesired by-products nitrite and bromate was investigated. The combination of VUV irradiation with ozone produced by a VUV lamp avoided the formation of relevant concentrations of the by-products. The internal generation of ozone is capable to produce ozone concentrations sufficient to reduce EE/O below 1 kWh m(-3) and without the risk of the formation of nitrite or bromate above the maximum contaminant level.

  6. Removal of diethyl phthalate from water solution by adsorption, photo-oxidation, ozonation and advanced oxidation process (UV/H₂O₂, O₃/H₂O₂ and O₃/activated carbon).

    PubMed

    Medellin-Castillo, Nahum A; Ocampo-Pérez, Raúl; Leyva-Ramos, Roberto; Sanchez-Polo, Manuel; Rivera-Utrilla, José; Méndez-Díaz, José D

    2013-01-01

    The objective of this work was to compare the effectiveness of conventional technologies (adsorption on activated carbon, AC, and ozonation) and technologies based on advanced oxidation processes, AOPs, (UV/H(2)O(2), O(3)/AC, O(3)/H(2)O(2)) to remove phthalates from aqueous solution (ultrapure water, surface water and wastewater). Diethyl phthalate (DEP) was chosen as a model pollutant because of its high water solubility (1,080 mg/L at 293 K) and toxicity. The activated carbons showed a high adsorption capacity to adsorb DEP in aqueous solution (up to 858 mg/g), besides the adsorption mechanism of DEP on activated carbon is governed by dispersive interactions between π electrons of its aromatic ring with π electrons of the carbon graphene planes. The photodegration process showed that the pH solution does not significantly affect the degradation kinetics of DEP and the first-order kinetic model satisfactorily fitted the experimental data. It was observed that the rate of decomposition of DEP with the O(3)/H(2)O(2) and O(3)/AC systems is faster than that with only O(3). The technologies based on AOPs (UV/H(2)O(2), O(3)/H(2)O(2), O(3)/AC) significantly improve the degradation of DEP compared to conventional technologies (O(3), UV). AC adsorption, UV/H(2)O(2), O(3)/H(2)O(2), and O(3)/AC showed a high yield to remove DEP; however, the disadvantage of AC adsorption is its much longer time to reach maximum removal. The best system to treat water (ultrapure and natural) polluted with DEP is the O(3)/AC one since it achieved the highest DEP degradation and TOC removal, as well as the lower water toxicity.

  7. Advanced oxidation process sanitization of eggshell surfaces.

    PubMed

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

    2016-06-01

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

  8. Hybrid process for nitrogen oxides reduction

    SciTech Connect

    Epperly, W.R.; Sprague, B.N.

    1991-09-10

    This patent describes a process for reducing the nitrogen oxide concentration in the effluent from the combustion of a carbonaceous fuel. It comprises introducing into the effluent a first treatment agent comprising a nitrogenous composition selected from the group consisting of urea, ammonia, hexamethylenetetramine, ammonium salts of organic acids, 5- or 6-membered heterocyclic hydrocarbons having at least one cyclic nitrogen, hydroxy amino hydrocarbons, NH{sub 4}-lignosulfonate, fur-furylamine, tetrahydrofurylamine, hexamethylenediamine, barbituric acid, guanidine, guanidine carbonate, biguanidine, guanylurea sulfate, melamine, dicyandiamide, biuret, 1.1{prime}-azobisformamide, methylol urea, methylol urea-urea condensation product, dimethylol urea, methyl urea, dimethyl urea, calcium cyanamide, and mixtures thereof under conditions effective to reduce the nitrogen oxides concentration and ensure the presence of ammonia in the effluent; introducing into the effluent a second treatment agent comprising an oxygenated hydrocarbon at an effluent temperature of about 500{degrees} F. to about 1600{degrees} F. under conditions effective to oxidize nitric oxide in the effluent to nitrogen dioxide and ensure the presence of ammonia at a weight ratio of ammonia to nitrogen dioxide of about 1:5 to about 5:1; and contacting the effluent with an aqueous scrubbing solution having a pH of 12 or lower under conditions effective to cause nitrogen dioxide to be absorbed therein.

  9. Decolorization of Reactive Red 2 by advanced oxidation processes: Comparative studies of homogeneous and heterogeneous systems.

    PubMed

    Wu, Chung-Hsin; Chang, Chung-Liang

    2006-02-06

    This study investigated the decolorization of the Reactive Red 2 in water using advanced oxidation processes (AOPs): UV/TiO2, UV/SnO2, UV/TiO2+SnO2, O3, O3+MnO2, UV/O3 and UV/O3+TiO2+SnO2. Kinetic analyses indicated that the decolorization rates of Reactive Red 2 could be approximated as pseudo-first-order kinetics for both homogeneous and heterogeneous systems. The decolorization rate at pH 7 exceeded pH 4 and 10 in UV/TiO2 and UV/TiO2+SnO2 systems, respectively. However, the rate constants in the systems (including O3) demonstrated the order of pH 10>pH 7>pH 4. The UV/TiO2+SnO2 and O3+MnO2 systems exhibited a greater decolorization rate than the UV/TiO2 and O3 systems, respectively. Additionally, the promotion of rate depended on pH. The variation of dye concentration influenced the decolorization efficiency of heterogeneous systems more significant than homogeneous systems. Experimental results verified that decolorization and desulfuration occurred at nearly the same rate. Moreover, the decolorization rate constants at pH 7 in various systems followed the order of UV/O3 > or = O3+MnO2 > or = UV/O3+TiO2+SnO2 > O3 > UV/TiO2+SnO2 > or = UV/TiO2 > UV/SnO2.

  10. Treatment of florfenicol of synthetic trout fish farm wastewater through nanofiltration and photocatalyst oxidation.

    PubMed

    Esmaili, Zakie; Cheshmberah, Fatemeh; Solaimany Nazar, Ali R; Farhadian, Mehrdad

    2016-10-24

    The aquaculture system is a potential significant source of antibacterial agents. The removal of florfenicol (Flo) antibiotic from synthetic aqueous wastewater is performed by applying a commercial thin film composite polyamide nanofilter (NF). For concentrated wastewater treatment, the advanced oxidation process (AOP) is applied. The effects of pH, pressure and Flo concentration on removal efficiency of NF and the effects of pH, Flo concentration and dosage of hydrogen peroxide and contact time on the AOP are assessed. In the nanofiltration system, it is found that an increase in pH enhances the removal efficiency up to 99%. In this membrane, an increase of pressure between 4 and 7 bar would increase the removal percentage, followed by a decrease from 7 to 10 bar. In AOP, it is observed that the degradation efficiency of Flo increases by both an increase in its initial concentration up to values above 50 ppm and contact time. The degradation efficiency of Flo is at its highest in the pH range of 7-10. With increasing H2O2 dosage, from 0 to 500 ppm, the removal efficiency increases. The results of this study indicate that a combination of a polyamide nanofilteration together with an AOP introduces an effective manner of removing Flo antibiotic from synthetic trout fish farm wastewater.

  11. Reactor process using metal oxide ceramic membranes

    DOEpatents

    Anderson, Marc A.

    1994-01-01

    A reaction vessel for use in photoelectrochemical reactions includes as its reactive surface a metal oxide porous ceramic membrane of a catalytic metal such as titanium. The reaction vessel includes a light source and a counter electrode. A provision for applying an electrical bias between the membrane and the counter electrode permits the Fermi levels of potential reaction to be favored so that certain reactions may be favored in the vessel. The electrical biasing is also useful for the cleaning of the catalytic membrane. Also disclosed is a method regenerating a porous metal oxide ceramic membrane used in a photoelectrochemical catalytic process by periodically removing the reactants and regenerating the membrane using a variety of chemical, thermal, and electrical techniques.

  12. Reactor process using metal oxide ceramic membranes

    DOEpatents

    Anderson, M.A.

    1994-05-03

    A reaction vessel for use in photoelectrochemical reactions includes as its reactive surface a metal oxide porous ceramic membrane of a catalytic metal such as titanium. The reaction vessel includes a light source and a counter electrode. A provision for applying an electrical bias between the membrane and the counter electrode permits the Fermi levels of potential reaction to be favored so that certain reactions may be favored in the vessel. The electrical biasing is also useful for the cleaning of the catalytic membrane. Also disclosed is a method regenerating a porous metal oxide ceramic membrane used in a photoelectrochemical catalytic process by periodically removing the reactants and regenerating the membrane using a variety of chemical, thermal, and electrical techniques. 2 figures.

  13. Effect of H2O2 dosing strategy on sludge pretreatment by microwave-H2O2 advanced oxidation process.

    PubMed

    Wang, Yawei; Wei, Yuansong; Liu, Junxin

    2009-09-30

    Considering characteristics of breaking down H(2)O(2) into water and molecular oxygen by catalase in waste activated sludge (WAS), the effect of H(2)O(2) dosing strategy on sludge pretreatment by the advanced oxidation process (AOP) of microwave-H(2)O(2) was investigated by batch experiments for optimizing H(2)O(2) dosage. Results showed that the catalase in sludge was active at the low temperature range between 15 degrees C and 45 degrees C, and gradually lost activity from 60 degrees C to 80 degrees C. Therefore, the H(2)O(2) was dosed at 80 degrees C, to which the waste activated sludge was first heated by the microwave (MW), and then the sludge dosed with H(2)O(2) was continuously heated till 100 degrees C by the microwave. Results at different H(2)O(2) dosages showed that the higher the H(2)O(2) dosing ratio was, the more the SCOD and total organic carbon (TOC) were released into the supernatant, and the optimum range of H(2)O(2)/TCOD ratio should be between 0.1 and 1.0. The percentages of consumed H(2)O(2) in the AOP of microwave and H(2)O(2) treating the WAS were 25.38%, 22.53%, 14.82%, 13.61% and 19.63% at different H(2)O(2)/TCOD dosing ratios of 0.1, 0.5, 1, 2, 4, respectively. Along with the increasing H(2)O(2)/TCOD ratio, the contents of TCOD on particles, soluble substances and mineralization increased and the TCOD distribution on solids decreased.

  14. Degradation of dibutyl phthalate (DBP) by UV-254 nm/H2O2 photochemical oxidation: kinetics and influence of various process parameters.

    PubMed

    Wang, Dong; Duan, Xiaodi; He, Xuexiang; Dionysiou, Dionysios D

    2016-12-01

    Degradation of dibuytl phthalate (DBP), a plasticizer and also a widely distributed endocrine disruptor, by UV-254 nm/H2O2 advanced oxidation process (AOP) was investigated in this study. A significant DBP removal of 77.1 % at an initial concentration of 1.0 μM was achieved at UV fluence of 160 mJ/cm(2), initial H2O2 dosage of 1.0 mM, and pH of 7.6 ± 0.1. The DBP degradation exhibited a pseudo-first-order reaction kinetic pattern, with the rate constants linearly increasing with increasing H2O2 dosage while decreasing with increasing initial DBP concentration and pH value in a specific range. DBP destruction was significantly inhibited in the presence of alkalinity and natural organic matter (NOM), two known factors that should be taken a serious consideration of in the research and design of UV/H2O2-based AOPs. Presence of common inorganic anions (i.e., Cl(-), SO4(2-), and NO3(-)) and metal cations (i.e., Fe(3+) and Zn(2+)) had a slight impact on the degradation of DBP, although Cu(2+) could improve the degradation efficiency even at a concentration as low as 0.01 mg/L, suggesting a strong potential of applying UV/H2O2 for the removal of DBP with an environmental relevant level of copper.

  15. The Effect of AOP on Software Engineering, with Particular Attention to OIF and Event Quantification

    NASA Technical Reports Server (NTRS)

    Havelund, Klaus; Filman, Robert; Korsmeyer, David (Technical Monitor)

    2003-01-01

    We consider the impact of Aspect-Oriented Programming on Software Engineering, and, in particular, analyze two AOP systems, one of which does component wrapping and the other, quantification over events, for their software engineering effects.

  16. Oxalic acid mineralization by electrochemical oxidation processes.

    PubMed

    Huang, Yao-Hui; Shih, Yu-Jen; Liu, Cheng-Hong

    2011-04-15

    In this study, two electrochemical oxidation processes were utilized to mineralize oxalic acid which was a major intermediate compound in the oxidation of phenols and other aromatic compounds. The anode rod and cathode net were made of a titanium coated with RuO(2)/IrO(2) (Ti-DSA) and stainless steel (S.S. net, SUS304), respectively. First, the Fered-Fenton process, which used H(2)O(2) and Fe(2+) as additive reagents, achieved 85% of TOC removal. It proceeded with ligand-to-metal charge-transfer (LMCT), which was evidenced by the accumulation of metallic foil on the selected cathode. However, in the absence of H(2)O(2)/Fe(2+), it showed a higher TOC removal efficiency while using Cl(-) only as an additive reagent due to the formation of hypochlorite on the anode. It was also found that the mineralization of oxalic acid by electrolysis generated hypochlorite better than the dosage of commercial hypochlorite without electricity. Also, pH value was a major factor that affected the mineralization efficiency of the oxalic acid due to the chlorine chemistry. 99% TOC removal could be obtained by Cl(-) electrolysis in an acidic environment.

  17. Drosophila Jun kinase regulates expression of decapentaplegic via the ETS-domain protein Aop and the AP-1 transcription factor DJun during dorsal closure.

    PubMed

    Riesgo-Escovar, J R; Hafen, E

    1997-07-01

    During Drosophila embryogenesis, ectodermal cells of the lateral epithelium stretch in a coordinated fashion to internalize the amnioserosa cells and close the embryo dorsally. This process, dorsal closure, requires two signaling pathways: the Drosophila Jun-amino-terminal kinase (DJNK) pathway and the Dpp pathway. We have identified mutations in DJun and show that DJNK controls dorsal closure by activating DJun and inactivating the ETS repressor Aop/Yan by phosphorylation. DJun and Aop regulate dpp expression in the most dorsal row of cells. Secreted Dpp then instructs more ventrally located cells to stretch. Our results provide a causal link between the DJNK and Dpp pathways during dorsal closure. Interestingly, in vertebrates, transforming growth factor-beta and c-Jun regulate collagenase gene expression during wound healing, a process that also involves the closing of an epithelial sheath.

  18. High-temperature processing of oxide superconductors and superconducting oxide-silver oxide composite

    NASA Technical Reports Server (NTRS)

    Wu, M. K.; Loo, B. H.; Peters, P. N.; Huang, C. Y.

    1988-01-01

    High temperature processing was found to partially convert the green 211 phase oxide to 123 phase. High Tc superconductivity was observed in Bi-Sr-Cu-O and Y-Sr-Cu-O systems prepared using the same heat treatment process. High temperature processing presents an alternative synthetic route in the search for new high Tc superconductors. An unusual magnetic suspension with enhancement in critical current density was observed in the 123 and AgO composite.

  19. Decomposition of 3,5-dinitrobenzamide in aqueous solution during UV/H2O2 and UV/TiO2 oxidation processes.

    PubMed

    Yan, Yingjie; Liao, Qi-Nan; Ji, Feng; Wang, Wei; Yuan, Shoujun; Hu, Zhen-Hu

    2017-02-01

    3,5-Dinitrobenzamide has been widely used as a feed additive to control coccidiosis in poultry, and part of the added 3,5-dinitrobenzamide is excreted into wastewater and surface water. The removal of 3,5-dinitrobenzamide from wastewater and surface water has not been reported in previous studies. Highly reactive hydroxyl radicals from UV/hydrogen peroxide (H2O2) and UV/titanium dioxide (TiO2) advanced oxidation processes (AOPs) can decompose organic contaminants efficiently. In this study, the decomposition of 3,5-dinitrobenzamide in aqueous solution during UV/H2O2 and UV/TiO2 oxidation processes was investigated. The decomposition of 3,5-dinitrobenzamide fits well with a fluence-based pseudo-first-order kinetics model. The decomposition in both two oxidation processes was affected by solution pH, and was inhibited under alkaline conditions. Inorganic anions such as NO3(-), Cl(-), SO4(2-), HCO3(-), and CO3(2-) inhibited the degradation of 3,5-dinitrobenzamide during the UV/H2O2 and UV/TiO2 oxidation processes. After complete decomposition in both oxidation processes, approximately 50% of 3,5-dinitrobenzamide was decomposed into organic intermediates, and the rest was mineralized to CO2, H2O, and other inorganic anions. Ions such as NH4(+), NO3(-), and NO2(-) were released into aqueous solution during the degradation. The primary decomposition products of 3,5-dinitrobenzamide were identified using time-of-flight mass spectrometry (LCMS-IT-TOF). Based on these products and ions release, a possible decomposition pathway of 3,5-dinitrobenzamide in both UV/H2O2 and UV/TiO2 processes was proposed.

  20. The adverse outcome pathway (AOP) for chemical binding to tubulin in oocytes leading to aneuploid offspring.

    PubMed

    Marchetti, Francesco; Massarotti, Alberto; Yauk, Carole L; Pacchierotti, Francesca; Russo, Antonella

    2016-03-01

    The Organisation for Economic Co-operation and Development (OECD) has launched the Adverse Outcome Pathway (AOP) Programme to advance knowledge of pathways of toxicity and improve the use of mechanistic information in risk assessment. An AOP links a molecular initiating event (MIE) to an adverse outcome (AO) through intermediate key events (KE). Here, we present the scientific evidence in support of an AOP whereby chemicals that bind to tubulin cause microtubule depolymerization resulting in spindle disorganization followed by altered chromosome alignment and segregation and the generation of aneuploidy in female germ cells, ultimately leading to aneuploidy in the offspring. Aneuploidy, an abnormal number of chromosomes that is not an exact multiple of the haploid number, is a well-known cause of human disease and represents a major cause of infertility, pregnancy failure, and serious genetic disorders in the offspring. Among chemicals that induce aneuploidy in female germ cells, a large majority impairs microtubule dynamics and spindle function. Colchicine, a prototypical chemical that binds to tubulin and causes microtubule depolymerization, is used here to illustrate the AOP. This AOP is specific to female germ cells exposed during the periovulation period. Although the majority of the data come from rodent studies, the available evidence suggests that the MIE and KEs are conserved across species and would occur in human oocytes. The development of AOPs related to mutagenicity in germ cells is expected to aid the identification of potential hazards to germ cell genomic integrity and support regulatory efforts to protect population health.

  1. Process for fabrication of metal oxide films

    SciTech Connect

    Tracy, C.E.; Benson, D.; Svensson, S.

    1990-07-17

    This invention is comprised of a method of fabricating metal oxide films from a plurality of reactants by inducing a reaction by plasma deposition among the reactants. The plasma reaction is effective for consolidating the reactants and producing thin films of metal oxides, e.g. electro-optically active transition metal oxides, at a high deposition rate. The presence of hydrogen during the plasma reaction enhances the deposition rate of the metal oxide. Various types of metal oxide films can be produced.

  2. Increased formation of halomethanes during chlorination of chloramphenicol in drinking water by UV irradiation, persulfate oxidation, and combined UV/persulfate pre-treatments.

    PubMed

    Wenhai, Chu; Tengfei, Chu; Erdeng, Du; Deng, Yang; Yingqing, Guo; Naiyun, Gao

    2016-02-01

    Ultraviolet/persulfate (UV/PS) has been widely used to generate sulfate radicals for degradation of water organic pollutants in previous studies. However, its impacts on disinfection byproduct formation during post-chlorination of degraded compounds is unclear. The objective of this study was to evaluate the impacts of UV irradiation, PS oxidation, and the combined UV/PS advanced oxidation process (AOP) pre-treatments on halomethane formation during the following chlorination of chloramphenicol (CAP), a model antibiotic commonly found in wastewater-impacted water. Results showed that CAP could be transformed to more trichloromethane (TCM) than monochloromethane (MCM) and dichloromethane (DCM) in the presence of excess chlorine. UV photolysis, PS oxidation and UV/PS AOP all directly decomposed CAP to produce halomethanes (HMs) before post-chlorination. Moreover, UV and UV/PS pre-treatments both enhanced the formation of all the HMs in the subsequent chlorination. PS pre-oxidation decreased the TCM formation during post-chlorination, but increased the yields of MCM, DCM and total HMs. UV pre-irradiation significantly increased the bromide utilization of HMs, whereas UV/PS pre-oxidation decreased the bromine incorporation and utilization of HMs from the chlorination of CAP in a low-bromide water. UV irradiation, PS oxidation, and UV/PS AOP can inactivate pathogens and degrade organic pollutants, but this benefit should be weighed against a potential risk of the increased halomethane formation from degraded organic pollutants with and without post-chlorination.

  3. Process for selected gas oxide removal by radiofrequency catalysts

    DOEpatents

    Cha, Chang Y.

    1993-01-01

    This process to remove gas oxides from flue gas utilizes adsorption on a char bed subsequently followed by radiofrequency catalysis enhancing such removal through selected reactions. Common gas oxides include SO.sub.2 and NO.sub.x.

  4. Application of hydrogen injection and oxidation to low temperature solution-processed oxide semiconductors

    NASA Astrophysics Data System (ADS)

    Miyakawa, Masashi; Nakata, Mitsuru; Tsuji, Hiroshi; Fujisaki, Yoshihide; Yamamoto, Toshihiro

    2016-08-01

    Solution-processed oxide semiconductors are promising candidates for the low cost, large scale fabrication of oxide thin-film transistors (TFTs). In this work, a method using hydrogen injection and oxidation (HIO) that allows the low temperature solution processing of oxide semiconductors was demonstrated. We found that this method significantly decreases the concentration of residual species while improving the film densification. Additionally, enhanced TFT performance was confirmed following the use of processing temperatures as low as 300 °C. The proposed process is potentially applicable to the fabrication of a wide variety of solution-processed oxide semiconductors.

  5. PROCESS OF PRODUCING REFRACTORY URANIUM OXIDE ARTICLES

    DOEpatents

    Hamilton, N.E.

    1957-12-01

    A method is presented for fabricating uranium oxide into a shaped refractory article by introducing a uranium halide fluxing reagent into the uranium oxide, and then mixing and compressing the materials into a shaped composite mass. The shaped mass of uranium oxide and uranium halide is then fired at an elevated temperature so as to form a refractory sintered article. It was found in the present invention that the introduction of a uraninm halide fluxing agent afforded a fluxing action with the uranium oxide particles and that excellent cohesion between these oxide particles was obtained. Approximately 90% of uranium dioxide and 10% of uranium tetrafluoride represent a preferred composition.

  6. AOP: An R Package For Sufficient Causal Analysis in Pathway ...

    EPA Pesticide Factsheets

    Summary: How can I quickly find the key events in a pathway that I need to monitor to predict that a/an beneficial/adverse event/outcome will occur? This is a key question when using signaling pathways for drug/chemical screening in pharma-cology, toxicology and risk assessment. By identifying these sufficient causal key events, we have fewer events to monitor for a pathway, thereby decreasing assay costs and time, while maximizing the value of the information. I have developed the “aop” package which uses backdoor analysis of causal net-works to identify these minimal sets of key events that are suf-ficient for making causal predictions. Availability and Implementation: The source and binary are available online through the Bioconductor project (http://www.bioconductor.org/) as an R package titled “aop”. The R/Bioconductor package runs within the R statistical envi-ronment. The package has functions that can take pathways (as directed graphs) formatted as a Cytoscape JSON file as input, or pathways can be represented as directed graphs us-ing the R/Bioconductor “graph” package. The “aop” package has functions that can perform backdoor analysis to identify the minimal set of key events for making causal predictions.Contact: burgoon.lyle@epa.gov This paper describes an R/Bioconductor package that was developed to facilitate the identification of key events within an AOP that are the minimal set of sufficient key events that need to be tested/monit

  7. Kinetic removal of haloacetonitrile precursors by photo-based advanced oxidation processes (UV/H2O2, UV/O3, and UV/H2O2/O3).

    PubMed

    Srithep, Sirinthip; Phattarapattamawong, Songkeart

    2017-06-01

    The objective of the study is to evaluate the performance of conventional treatment process (i.e., coagulation, flocculation, sedimentation and sand filtration) on the removals of haloacetonitrile (HAN) precursors. In addition, the removals of HAN precursors by photo-based advanced oxidation processes (Photo-AOPs) (i.e., UV/H2O2, UV/O3, and UV/H2O2/O3) are investigated. The conventional treatment process was ineffective to remove HAN precursors. Among Photo-AOPs, the UV/H2O2/O3 was the most effective process for removing HAN precursors, followed by UV/H2O2, and UV/O3, respectively. For 20min contact time, the UV/H2O2/O3, UV/H2O2, and UV/O3 suppressed the HAN formations by 54, 42, and 27% reduction. Increasing ozone doses from 1 to 5 mgL(-1) in UV/O3 systems slightly improved the removals of HAN precursors. Changes in pH (6-8) were unaffected most of processes (i.e., UV, UV/H2O2, and UV/H2O2/O3), except for the UV/O3 system that its efficiency was low in the weak acid condition. The pseudo first-order kinetic constant for removals of dichloroacetonitrile precursors (k'DCANFP) by the UV/H2O2/O3, UV/H2O2 and standalone UV systems were 1.4-2.8 orders magnitude higher than the UV/O3 process. The kinetic degradation of dissolved organic nitrogen (DON) tended to be higher than the k'DCANFP value. This study firstly differentiates the kinetic degradation between DON and HAN precursors.

  8. Mechanistic modeling of vacuum UV advanced oxidation process in an annular photoreactor.

    PubMed

    Crapulli, F; Santoro, D; Sasges, M R; Ray, A K

    2014-11-01

    A novel mechanistic model that describes the vacuum UV advanced oxidation process in an annular photoreactor initiated by 172 nm and 185 nm (in combination with 253.7 nm, with and without exogenous H2O2) is presented in this paper. The model was developed from first principles by incorporating the vacuum UV-AOP kinetics into the theoretical framework of in-series continuous flow stirred tank reactors. After conducting a sensitivity analysis, model predictions were compared against experiments conducted under a variety of conditions: (a) photo-induced formation of hydrogen peroxide by water photolysis at 172 nm (for both air- and oxygen-saturated conditions); (b) photo-induced formation of hydrogen peroxide by water photolysis at 185 + 253.7 nm (in the presence of formic acid, with and without the initial addition of hydrogen peroxide); (c) direct photolysis of hydrogen peroxide by 253.7 nm; (d) degradation of formic acid by 185 + 253.7 nm (with and without initial addition of hydrogen peroxide); and (e) degradation of formic acid by 253.7 nm (with the addition of exogenous hydrogen peroxide). In all cases, the model was able to accurately predict the time-dependent profiles of hydrogen peroxide and formic acid concentrations. Two newly recognized aspects associated with water photolysis were identified through the use of the validated model. Firstly, unlike the 185 nm and 253.7 nm cases, water photolysis by the 172 nm wavelength revealed a depth of photoactive water layer an order of magnitude greater (∼230-390 μm, depending on the specific operating conditions) than the 1-log photon penetration layer (∼18 μm). To further investigate this potentially very important finding, a computational fluid dynamics model was set up to assess the role of transport mechanisms and species distributions within the photoreactor annulus. The model confirmed that short-lived hydroxyl radicals were present at a radial distance far beyond the ∼18 μm photon

  9. Oxidation Ditches. Student Manual. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Nelsen, David

    The textual material for a two-lesson unit on oxidation ditches is presented in this student manual. Topics discussed in the first lesson (introduction, theory, and components) include: history of the oxidation ditch process; various designs of the oxidation ditch; multi-trench systems; carrousel system; advantages and disadvantages of the…

  10. Review of solution-processed oxide thin-film transistors

    NASA Astrophysics Data System (ADS)

    Kim, Si Joon; Yoon, Seokhyun; Kim, Hyun Jae

    2014-02-01

    In this review, we summarize solution-processed oxide thin-film transistors (TFTs) researches based on our fulfillments. We describe the fundamental studies of precursor composition effects at the beginning in order to figure out the role of each component in oxide semiconductors, and then present low temperature process for the adoption of flexible devices. Moreover, channel engineering for high performance and reliability of solution-processed oxide TFTs and various coating methods: spin-coating, inkjet printing, and gravure printing are also presented. The last topic of this review is an overview of multi-functional solution-processed oxide TFTs for various applications such as photodetector, biosensor, and memory.

  11. Modeling hydroxyl radical distribution and trialkyl phosphates oxidation in UV-H2O2 photoreactors using computational fluid dynamics.

    PubMed

    Santoro, Domenico; Raisee, Mehrdad; Moghaddami, Mostafa; Ducoste, Joel; Sasges, Micheal; Liberti, Lorenzo; Notarnicola, Michele

    2010-08-15

    Advanced Oxidation Processes (AOPs) promoted by ultraviolet light are innovative and potentially cost-effective solutions for treating persistent pollutants recalcitrant to conventional water and wastewater treatment. While several studies have been performed during the past decade to improve the fundamental understanding of the UV-H(2)O(2) AOP and its kinetic modeling, Computational Fluid Dynamics (CFD) has only recently emerged as a powerful tool that allows a deeper understanding of complex photochemical processes in environmental and reactor engineering applications. In this paper, a comprehensive kinetic model of UV-H(2)O(2) AOP was coupled with the Reynolds averaged Navier-Stokes (RANS) equations using CFD to predict the oxidation of tributyl phosphate (TBP) and tri(2-chloroethtyl) phosphate (TCEP) in two different photoreactors: a parallel- and a cross-flow UV device employing a UV lamp emitting primarily 253.7 nm radiation. CFD simulations, obtained for both turbulent and laminar flow regimes and compared with experimental data over a wide range of UV doses, enabled the spatial visualization of hydrogen peroxide and hydroxyl radical distributions in the photoreactor. The annular photoreactor displayed consistently better oxidation performance than the cross-flow system due to the absence of recirculation zones, as confirmed by the hydroxyl radical dose distributions. Notably, such discrepancy was found to be strongly dependent on and directly correlated with the hydroxyl radical rate constant becoming relevant for conditions approaching diffusion-controlled reaction regimes (k(C,OH) > 10(9) M(-1) s(-1)).

  12. Performance evaluation of different solar advanced oxidation processes applied to the treatment of a real textile dyeing wastewater.

    PubMed

    Manenti, Diego R; Soares, Petrick A; Silva, Tânia F C V; Módenes, Aparecido N; Espinoza-Quiñones, Fernando R; Bergamasco, Rosângela; Boaventura, Rui A R; Vilar, Vítor J P

    2015-01-01

    The performance of different solar-driven advanced oxidation processes (AOPs), such as TiO2/UV, TiO2/H2O2/UV, and Fe(2+)/H2O2/UV-visible in the treatment of a real textile effluent using a pilot plant with compound parabolic collectors (CPCs), was investigated. The influence of the main photo-Fenton reaction variables such as iron concentration (20-100 mg Fe(2+) L(-1)), pH (2.4-4.5), temperature (10-50 °C), and irradiance (22-68 WUV m(-2)) was evaluated in a lab-scale prototype using artificial solar radiation. The real textile wastewater presented a beige color, with a maximum absorbance peak at 641 nm, alkaline pH (8.1), moderate organic content (dissolved organic carbon (DOC) = 129 mg C L(-1) and chemical oxygen demand (COD) = 496 mg O2 L(-1)), and high conductivity mainly associated to the high concentration of chloride (1.1 g Cl(-) L(-1)), sulfate (0.4 g SO 4 (2 -) L(- 1)), and sodium (1.2 g Na(+) L(-1)) ions. Although all the processes tested contributed to complete decolorization and effective mineralization, the most efficient process was the solar photo-Fenton with an optimum catalyst concentration of 60 mg Fe(2+) L(-1), leading to 70 % mineralization (DOCfinal = 41 mg C L(-1); CODfinal < 150 mg O2 L(-1)) at pH 3.6, requiring a UV energy dose of 3.5 kJUV L(-1) (t 30 W = 22.4 min; [Formula: see text]; [Formula: see text]) and consuming 18.5 mM of H2O2.

  13. An AOP analysis of selective serotonin reuptake inhibitors (SSRIs) for fish.

    PubMed

    Danielle McDonald, M

    2017-03-10

    Pharmaceuticals and personal care products (PPCPs) are found in measureable quantities within the aquatic environment. Selective serotonin reuptake inhibitor (SSRI) antidepressants are one class of pharmaceutical compound that has received a lot of attention. Consistent with most PPCPs, the pharmacokinetics and physiological impacts of SSRI treatment have been well-studied in small mammals and humans and this, combined with the evolutionary conservation of the serotonergic system across vertebrates, allows for the read-across of known SSRI effects in mammals to potential SSRI impacts on aquatic organisms. Using an Adverse Outcome Pathway (AOP) framework, this review examines the similarities and differences between the mammalian and teleost fish SSRI target, the serotonin transporter (SERT; SLC6A4), and the downstream impacts of elevated extracellular serotonin (5-HT; 5-hydroxytryptamine), the consequence of SERT inhibition, on organ systems and physiological processes within teleost fish. This review also intends to reveal potentially understudied endpoints for SSRI toxicity based on what is known to be controlled by 5-HT in fish.

  14. Comparison of Infectious Agents Susceptibility to Photocatalytic Effects of Nanosized Titanium and Zinc Oxides: A Practical Approach

    NASA Astrophysics Data System (ADS)

    Bogdan, Janusz; Zarzyńska, Joanna; Pławińska-Czarnak, Joanna

    2015-08-01

    Nanotechnology contributes towards a more effective eradication of pathogens that have emerged in hospitals, veterinary clinics, and food processing plants and that are resistant to traditional drugs or disinfectants. Since new methods of pathogens eradication must be invented and implemented, nanotechnology seems to have become the response to that acute need. A remarkable achievement in this field of science was the creation of self-disinfecting surfaces that base on advanced oxidation processes (AOPs). Thus, the phenomenon of photocatalysis was practically applied. Among the AOPs that have been most studied in respect of their ability to eradicate viruses, prions, bacteria, yeasts, and molds, there are the processes of TiO2/UV and ZnO/UV. Titanium dioxide (TiO2) and zinc oxide (ZnO) act as photocatalysts, after they have been powdered to nanoparticles. Ultraviolet (UV) radiation is an agent that determines their excitation. Methods using photocatalytic properties of nanosized TiO2 and ZnO prove to be highly efficient in inactivation of infectious agents. Therefore, they are being applied on a growing scale. AOP-based disinfection is regarded as a very promising tool that might help overcome problems in food hygiene and public health protection. The susceptibility of infectious agents to photocatalylic processes can be generally arranged in the following order: viruses > prions > Gram-negative bacteria > Gram-positive bacteria > yeasts > molds.

  15. Comparison of Infectious Agents Susceptibility to Photocatalytic Effects of Nanosized Titanium and Zinc Oxides: A Practical Approach.

    PubMed

    Bogdan, Janusz; Zarzyńska, Joanna; Pławińska-Czarnak, Joanna

    2015-12-01

    Nanotechnology contributes towards a more effective eradication of pathogens that have emerged in hospitals, veterinary clinics, and food processing plants and that are resistant to traditional drugs or disinfectants. Since new methods of pathogens eradication must be invented and implemented, nanotechnology seems to have become the response to that acute need. A remarkable achievement in this field of science was the creation of self-disinfecting surfaces that base on advanced oxidation processes (AOPs). Thus, the phenomenon of photocatalysis was practically applied. Among the AOPs that have been most studied in respect of their ability to eradicate viruses, prions, bacteria, yeasts, and molds, there are the processes of TiO2/UV and ZnO/UV. Titanium dioxide (TiO2) and zinc oxide (ZnO) act as photocatalysts, after they have been powdered to nanoparticles. Ultraviolet (UV) radiation is an agent that determines their excitation. Methods using photocatalytic properties of nanosized TiO2 and ZnO prove to be highly efficient in inactivation of infectious agents. Therefore, they are being applied on a growing scale. AOP-based disinfection is regarded as a very promising tool that might help overcome problems in food hygiene and public health protection. The susceptibility of infectious agents to photocatalylic processes can be generally arranged in the following order: viruses > prions > Gram-negative bacteria > Gram-positive bacteria > yeasts > molds.

  16. Inactivation of adenovirus using low-dose UV/H2O2 advanced oxidation.

    PubMed

    Bounty, Sarah; Rodriguez, Roberto A; Linden, Karl G

    2012-12-01

    Adenovirus has consistently been observed to be the most resistant known pathogen to disinfection by ultraviolet light. This has had an impact on regulations set by the United States Environmental Protection Agency regarding the use of UV disinfection for virus inactivation in groundwater and surface water. In this study, enhancement of UV inactivation of adenovirus was evaluated when hydrogen peroxide was added to create an advanced oxidation process (AOP). While 4 log reduction of adenovirus was determined to require a UV dose (UV fluence) of about 200 mJ/cm(2) from a low pressure (LP) UV source (emitting at 253.7 nm), addition of 10 mg/L H(2)O(2) achieved 4 log inactivation at a dose of 120 mJ/cm(2). DNA damage was assessed using a novel nested PCR approach, and similar levels of DNA damage between the two different treatments were noted, suggesting the AOP enhancement in inactivation was not due to additional DNA damage. Hydroxyl radicals produced in the advanced oxidation process are likely able to damage parts of the virus not targeted by LPUV, such as attachment proteins, enhancing the UV-induced inactivation. The AOP-enhanced inactivation potential was modeled in three natural waters. This research sheds light on the inactivation mechanisms of viruses with ultraviolet light and in the presence of hydroxyl radicals and provides a practical means to enhance inactivation of this UV-resistant virus.

  17. Synthesis and processing of monosized oxide powders

    DOEpatents

    Barringer, E.A.; Fegley, M.B. Jr.; Bowen, H.K.

    1985-09-24

    Uniform-size, high-purity, spherical oxide powders are formed by hydrolysis of alkoxide precursors in dilute alcoholic solutions. Under controlled conditions (concentrations of 0.03 to 0.2 M alkoxide and 0.2 to 1.5 M water, for example) oxide particles on the order of about 0.05 to 0.7 microns can be produced. Methods of doping such powders and forming sinterable compacts are also disclosed. 6 figs.

  18. Synthesis and processing of monosized oxide powders

    DOEpatents

    Barringer, Eric A.; Fegley, Jr., M. Bruce; Bowen, H. Kent

    1985-01-01

    Uniform-size, high-purity, spherical oxide powders are formed by hydrolysis of alkoxide precursors in dilute alcoholic solutions. Under controlled conditions (concentrations of 0.03 to 0.2 M alkoxide and 0.2 to 1.5 M water, for example) oxide particles on the order of about 0.05 to 0.7 micron can be produced. Methods of doping such powders and forming sinterable compacts are also disclosed.

  19. Assessing the application of advanced oxidation processes, and their combination with biological treatment, to effluents from pulp and paper industry.

    PubMed

    Merayo, Noemí; Hermosilla, Daphne; Blanco, Laura; Cortijo, Luis; Blanco, Angeles

    2013-11-15

    The closure of water circuits within pulp and paper mills has resulted in a higher contamination load of the final mill effluent, which must consequently be further treated in many cases to meet the standards imposed by the legislation in force. Different treatment strategies based on advanced oxidation processes (ozonation and TiO2-photocatalysis), and their combination with biological treatment (MBR), are herein assessed for effluents of a recycled paper mill and a kraft pulp mill. Ozone treatment achieved the highest efficiency of all. The consumption of 2.4 g O3 L(-1) resulted in about a 60% COD reduction treating the effluent from the kraft pulp mill at an initial pH=7; although it only reached about a 35% COD removal for the effluent of the recycled paper mill. Otherwise, photocatalysis achieved about a 20-30% reduction of the COD for both type of effluents. In addition, the effluent from the recycled paper mill showed a higher biodegradability, so combinations of these AOPs with biological treatment were tested. As a result, photocatalysis did not report any significant COD reduction improvement whether being performed as pre- or post-treatment of the biological process; whereas the use of ozonation as post-biological treatment enhanced COD removal a further 10%, summing up a total 90% reduction of the COD for the combined treatment, as well as it also supposed an increase of the presence of volatile fatty acids, which might ultimately enable the resultant wastewater to be recirculated back to further biological treatment.

  20. Low Temperature Processed Complementary Metal Oxide Semiconductor (CMOS) Device by Oxidation Effect from Capping Layer

    PubMed Central

    Wang, Zhenwei; Al-Jawhari, Hala A.; Nayak, Pradipta K.; Caraveo-Frescas, J. A.; Wei, Nini; Hedhili, M. N.; Alshareef, H. N.

    2015-01-01

    In this report, both p- and n-type tin oxide thin-film transistors (TFTs) were simultaneously achieved using single-step deposition of the tin oxide channel layer. The tuning of charge carrier polarity in the tin oxide channel is achieved by selectively depositing a copper oxide capping layer on top of tin oxide, which serves as an oxygen source, providing additional oxygen to form an n-type tin dioxide phase. The oxidation process can be realized by annealing at temperature as low as 190°C in air, which is significantly lower than the temperature generally required to form tin dioxide. Based on this approach, CMOS inverters based entirely on tin oxide TFTs were fabricated. Our method provides a solution to lower the process temperature for tin dioxide phase, which facilitates the application of this transparent oxide semiconductor in emerging electronic devices field. PMID:25892711

  1. Photochemical oxidation of p-chlorophenol by UV/H2O2 and photo-Fenton process. A comparative study.

    PubMed

    Ghaly, M Y; Härtel, G; Mayer, R; Haseneder, R

    2001-01-01

    In this study, photochemical advanced oxidation processes (AOPs) utilizing the combinations of UV/H2O2 and the photo-Fenton reaction (UV + classical Fenton reaction) were investigated in lab-scale experiments for the degradation of p-chlorophenol. The study showed that the photo-Fenton process, (a mixture of hydrogen peroxide and ferrous or ferric ion), was the most effective treatment process under acidic conditions and produced a higher rate of degradation of p-chlorophenol at a very short radiation time. It accelerated the oxidation rate by 5-9 times the rate for the UV/H2O2 process. The reaction was found to follow the first order, the reaction was influenced by the pH, the input concentration of H2O2 and the amount of the iron catalyst and the type of iron salt. The experimental results showed that the optimum conditions were obtained at a pH value of 3, with 0.03 mol/l H2O2, and 1 mmol/l Fe(II) for the UV/H2O2/Fe(II) system and 0.01 mol/l H2O2 and, 0.4 mmol/l Fe(III) for the UV/H2O2/Fe(III) system. The reactions were accompanied by the generation of Cl- which reached its maximum value at a short reaction time when using the photo-Fenton process. Finally a rough comparison of the specific energy consumption shows that photo-Fenton process reduced the energy consumption by at least 73 to 83% compared with the UV/H2O2 process.

  2. Surface etching and roughening in integrated processing of thermal oxides

    NASA Astrophysics Data System (ADS)

    Offenberg, M.; Liehr, M.; Rubloff, G. W.

    1991-04-01

    A multichamber UHV processing and analysis system has been used to study integrated thermal oxide processing, in which the final precleaning process and the thermal oxidation process are integrated by employing transfer of the wafers through ultraclean, inert ambients (purified, dry N2 and then ultrahigh vacuum). The Al-gate MOS capacitors show high breakdown fields (approximately 12 MV/cm) when a thin oxide passivation layer is present prior to oxidation, but low fields (less than 6 MV/cm) when the Si surface is initially oxygen free. This contrasting behavior is caused by the etching of Si surfaces which occurs at elevated temperature in the presence of trace concentration (approximately 100 ppb) of oxygen (e.g., 2 Si + O2 yields 2SiO2), leading to surface roughening and then field enhancement at asperities in the structure. Oxide surface passivation prevents etching and assures the dielectric integrity of the structure.

  3. Catalyst and process for oxidizing hydrogen sulfide

    SciTech Connect

    Hass, R.H.; Ward, J.W.

    1984-04-24

    Catalysts comprising bismuth and vanadium components are highly active and stable, especially in the presence of water vapor, for oxidizing hydrogen sulfide to sulfur or SO/sub 2/. Such catalysts have been found to be especially active for the conversion of hydrogen sulfide to sulfur by reaction with oxygen or SO/sub 2/.

  4. Conversion of Sulfur by Wet Oxidation in the Bayer Process

    NASA Astrophysics Data System (ADS)

    Liu, Zhanwei; Li, Wangxing; Ma, Wenhui; Yin, Zhonglin; Wu, Guobao

    2015-08-01

    In this paper, the effects of temperature, oxidation time, and oxygen concentration on the conversion of sulfur by wet oxidation in the Bayer process were investigated at length. The results show that active sulfur S2- and S2O3 2- in sodium aluminate solution can be converted completely by wet oxidation during the digestion process, thus the effects of S2- and S2O3 2- on alumina product quality are eliminated; increased temperature, oxidation time, and oxygen concentration are conducive to conversion of S2- and S2O3 2-. At the same time, part of the organic carbon in the sodium aluminate solution is also oxidized by wet oxidation, and the color of the sodium aluminate solution noticeably fades.

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

    PubMed

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

    2014-01-01

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

  6. Case Study: AOP, Alliance Organizing Project. Strong Neighborhoods, Strong Schools. The Indicators Project on Education Organizing.

    ERIC Educational Resources Information Center

    Gold, Eva; Pickron-Davis, Marcine; Brown, Chris

    This report describes Philadelphia, Pennsylvania's, Alliance Organizing Project (AOP), which organized parents and families of Philadelphia's public school students to become full partners in Philadelphia school reform. It is one of five case studies in the Indicators Project on Education Organizing, which identified eight indicators of the impact…

  7. AOP Wiki: A new tool for developing and documenting adverse outcome pathways

    EPA Science Inventory

    An initial version of an IT system to support OECD AOP activities recently was completed through collaborative efforts and contributions of the European Commission's Joint Research Centre (EU JRC), the Office of Research and Development (ORD) of the United States Environmental Pr...

  8. Fish early life stage: Developing AOPs to support targeted reduction and replacement

    EPA Science Inventory

    There is an interest in developing alternatives to the fish early-life stage (FELS) test (OECD test guideline 210), for predicting adverse chronic toxicity outcomes (e.g., impacts on growth and survival). Development and characterization of adverse outcome pathways (AOPs) related...

  9. Quantitative AOP linking aromatase inhibition to impaired reproduction: A case study in predictive ecotoxicology

    EPA Science Inventory

    The adverse outcome pathway (AOP) framework is intended to help support greater use of mechanistic toxicology data as a basis for risk assessment and/or regulatory decision-making. While there have been clear advances in the ability to rapidly generate mechanistically-oriented da...

  10. The potential of AOP networks for reproductive and developmental toxicity assay development

    EPA Science Inventory

    Historically, the prediction of reproductive and early developmental toxicity has largely relied on the use of animals. The Adverse Outcome Pathway (AOP) framework forms a basis for the development of new non-animal test methods. It also provides biological context for mechanisti...

  11. Investigation of oxidation process of mechanically activated ultrafine iron powders

    NASA Astrophysics Data System (ADS)

    Lysenko, E. N.; Nikolaev, E. V.; Vlasov, V. A.; Zhuravkov, S. P.

    2016-02-01

    The oxidation of mechanically activated ultrafine iron powders was studied using X- ray powder diffraction and thermogravimetric analyzes. The powders with average particles size of 100 nm were made by the electric explosion of wire, and were subjected to mechanical activation in planetary ball mill for 15 and 40 minutes. It was shown that a certain amount of FeO phase is formed during mechanical activation of ultrafine iron powders. According to thermogravimetric analysis, the oxidation process of non-milled ultrafine iron powders is a complex process and occurs in three stages. The preliminary mechanical activation of powders considerably changes the nature of the iron powders oxidation, leads to increasing in the temperature of oxidation onset and shifts the reaction to higher temperatures. For the milled powders, the oxidation is more simple process and occurs in a single step.

  12. Process for producing metal compounds from graphite oxide

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh (Inventor)

    2000-01-01

    A process for providing elemental metals or metal oxides distributed on a carbon substrate or self-supported utilizing graphite oxide as a precursor. The graphite oxide is exposed to one or more metal chlorides to form an intermediary product comprising carbon, metal, chloride, and oxygen This intermediary product can be flier processed by direct exposure to carbonate solutions to form a second intermediary product comprising carbon, metal carbonate, and oxygen. Either intermediary product may be further processed: a) in air to produce metal oxide; b) in an inert environment to produce metal oxide on carbon substrate; c) in a reducing environment to produce elemental metal distributed on carbon substrate. The product generally takes the shape of the carbon precursor.

  13. Process for Producing Metal Compounds from Graphite Oxide

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh (Inventor)

    2000-01-01

    A process for providing elemental metals or metal oxides distributed on a carbon substrate or self-supported utilizing graphite oxide as a precursor. The graphite oxide is exposed to one or more metal chlorides to form an intermediary product comprising carbon. metal. chloride. and oxygen This intermediary product can be flier processed by direct exposure to carbonate solutions to form a second intermediary product comprising carbon. metal carbonate. and oxygen. Either intermediary product may be further processed: a) in air to produce metal oxide: b) in an inert environment to produce metal oxide on carbon substrate: c) in a reducing environment. to produce elemental metal distributed on carbon substrate. The product generally takes the shape of the carbon precursor.

  14. Nitrous oxide emissions from wastewater treatment processes

    PubMed Central

    Law, Yingyu; Ye, Liu; Pan, Yuting; Yuan, Zhiguo

    2012-01-01

    Nitrous oxide (N2O) emissions from wastewater treatment plants vary substantially between plants, ranging from negligible to substantial (a few per cent of the total nitrogen load), probably because of different designs and operational conditions. In general, plants that achieve high levels of nitrogen removal emit less N2O, indicating that no compromise is required between high water quality and lower N2O emissions. N2O emissions primarily occur in aerated zones/compartments/periods owing to active stripping, and ammonia-oxidizing bacteria, rather than heterotrophic denitrifiers, are the main contributors. However, the detailed mechanisms remain to be fully elucidated, despite strong evidence suggesting that both nitrifier denitrification and the chemical breakdown of intermediates of hydroxylamine oxidation are probably involved. With increased understanding of the fundamental reactions responsible for N2O production in wastewater treatment systems and the conditions that stimulate their occurrence, reduction of N2O emissions from wastewater treatment systems through improved plant design and operation will be achieved in the near future. PMID:22451112

  15. Process for selected gas oxide removal by radiofrequency catalysts

    DOEpatents

    Cha, C.Y.

    1993-09-21

    This process to remove gas oxides from flue gas utilizes adsorption on a char bed subsequently followed by radiofrequency catalysis enhancing such removal through selected reactions. Common gas oxides include SO[sub 2] and NO[sub x]. 1 figure.

  16. Uranium Metal to Oxide Conversion by Air Oxidation –Process Development

    SciTech Connect

    Duncan, A

    2001-12-31

    Published technical information for the process of metal-to-oxide conversion of uranium components has been reviewed and summarized for the purpose of supporting critical decisions for new processes and facilities for the Y-12 National Security Complex. The science of uranium oxidation under low, intermediate, and high temperature conditions is reviewed. A process and system concept is outlined and process parameters identified for uranium oxide production rates. Recommendations for additional investigations to support a conceptual design of a new facility are outlined.

  17. Practical approaches to adverse outcome pathway (AOP) development and weight of evidence evaluation as illustrated by ecotoxicological case studies.

    PubMed

    Fay, Kellie A; Villeneuve, Daniel L; LaLone, Carlie A; Song, You; Tollefsen, Knut Erik; Ankley, Gerald T

    2017-02-15

    Adverse Outcome Pathways (AOPs) describe toxicant effects as a sequential chain of causally linked events beginning with a molecular perturbation and culminating in an adverse outcome at an individual or population level. Strategies for developing AOPs are still evolving and depend largely on the intended use or motivation for development and data availability. Four ecotoxicological AOP case studies, developed for different purposes, are described herein. In each situation, creation of the AOP began in a manner determined by the initial motivation for its creation, and expanded either to include additional components of the pathway, or to address the domains of applicability in terms of chemical initiators, susceptible species, life stages, etc. From these case studies, some general strategies can be gleaned which a developer may find useful for supporting an existing AOP or creating a new one. Several web-based tools which can aid in AOP assembly and evaluation of weight of evidence for scientific robustness of AOP components are highlighted. This article is protected by copyright. All rights reserved.

  18. Solid oxide electrochemical cell fabrication process

    DOEpatents

    Dollard, Walter J.; Folser, George R.; Pal, Uday B.; Singhal, Subhash C.

    1992-01-01

    A method to form an electrochemical cell (12) is characterized by the steps of thermal spraying stabilized zirconia over a doped lanthanum manganite air electrode tube (14) to provide an electrolyte layer (15), coating conductive particles over the electrolyte, pressurizing the outside of the electrolyte layer, feeding halide vapors of yttrium and zirconium to the outside of the electrolyte layer and feeding a source of oxygen to the inside of the electrolyte layer, heating to cause oxygen reaction with the halide vapors to close electrolyte pores if there are any and to form a metal oxide coating on and between the particles and provide a fuel electrode (16).

  19. Evaluation of Oxidation Processes for Treating Aqueous Chemical Mixtures

    DTIC Science & Technology

    1994-04-01

    to 0.1 ppm in a fixed time with 100-200 mM H202 or 03. From this information, we estimated the cost of treating 1000 gal of water containing 10 ppm...the most cost efficiency in generating HO-. The most efficient system for generating HOo is the H202/UJV system. However, this AOP is too slow to use...with high flow systems where short residence times require high rates of HO. generation. Faster rates could be obtained, but only at much higher cost

  20. Effect of advanced oxidation processes on the micropollutants and the effluent organic matter contained in municipal wastewater previously treated by three different secondary methods.

    PubMed

    Giannakis, Stefanos; Gamarra Vives, Franco Alejandro; Grandjean, Dominique; Magnet, Anoys; De Alencastro, Luiz Felippe; Pulgarin, César

    2015-11-01

    In this study, wastewater from the output of three different secondary treatment facilities (Activated Sludge, Moving Bed Bioreactor and Coagulation-Flocculation) present in the municipal wastewater treatment plant of Vidy, Lausanne (Switzerland), was further treated with various oxidation processes (UV, UV/H2O2, solar irradiation, Fenton, solar photo-Fenton), at laboratory scale. For this assessment, 6 organic micropollutants in agreement with the new environmental legislation requirements in Switzerland were selected (Carbamazepine, Clarithromycin, Diclofenac, Metoprolol, Benzotriazole, Mecoprop) and monitored throughout the treatment. Also, the overall removal of the organic load was assessed. After each secondary treatment, the efficiency of the AOPs increased in the following order: Coagulation-Flocculation < Activated Sludge < Moving Bed Bioreactor, in almost all cases. From the different combinations tested, municipal wastewater subjected to biological treatment followed by UV/H2O2 resulted in the highest elimination levels. Wastewater previously treated by physicochemical treatment demonstrated considerably inhibited micropollutant degradation rates. The degradation kinetics were determined, yielding: k (UV) < k (UV/H2O2) and k (Fenton) < k (solar irradiation) < k (photo-Fenton). Finally, the evolution of global pollution parameters (COD & TOC elimination) was followed and the degradation pathways for the effluent organic matter are discussed.

  1. The fate of H2O2 during managed aquifer recharge: A residual from advanced oxidation processes for drinking water production.

    PubMed

    Wang, F; van Halem, D; van der Hoek, J P

    2016-04-01

    The fate of H2O2 residual from advanced oxidation process (AOP) preceding managed aquifer recharge (MAR) is of concern because H2O2 could lead to undesired effects on organisms in the MAR aquatic and soil ecosystem. The objective of this study was to distinguish between factors affecting H2O2 decomposition in MAR systems, simulated in batch reactors with synthetic MAR water and slow sand filter sand. The results showed that pure sand and soil organic matter had no considerable effect on H2O2 decomposition, whereas naturally occurring inorganic substances on the surface of sand grains and microbial biomass are the two main factors accelerating H2O2 decomposition in MAR systems. Additionally, the results showed that the H2O2 decompositions with different initial concentrations fitted first-order kinetics in 2-6 h in a mixture of slow sand filter sand (as a substitute for sand from a MAR system) and synthetic MAR water with high bacterial population. An estimation indicated that low concentrations of H2O2 (<3 mg/L) could decompose to the provisional standard of 0.25 mg/L in the first centimeters of MAR systems with the influent water containing high microbial biomass 38 ng ATP/mL.

  2. Investigating the application of AOP methodology in development of Financial Accounting Software using Eclipse-AJDT Environment

    NASA Astrophysics Data System (ADS)

    Sharma, Amita; Sarangdevot, S. S.

    2010-11-01

    Aspect-Oriented Programming (AOP) methodology has been investigated in development of real world business application software—Financial Accounting Software. Eclipse-AJDT environment has been used as open source enhanced IDE support for programming in AOP language—Aspect J. Crosscutting concerns have been identified and modularized as aspects. This reduces the complexity of the design considerably due to elimination of code scattering and tangling. Improvement in modularity, quality and performance is achieved. The study concludes that AOP methodology in Eclipse-AJDT environment offers powerful support for modular design and implementation of real world quality business software.

  3. A green process to prepare chromic oxide green pigment.

    PubMed

    Li, Ping; Xu, Hong-Bin; Zheng, Shi-Li; Zhang, Yi; Li, Zuo-Hu; Bai, Yu-Lan

    2008-10-01

    A hydrogen reduction and activated sintering process was proposed to prepare chromic oxide green pigment. Through ICP, XRD, SEM, FT-IR, UV, and CIE-L*a*b* colorimetric analysis, key factors and mechanism that influenced preparation of chromic oxide green pigment were studied. The results revealed that lower hydrogen reduction temperature, suitable addition of Al and Ba, were beneficial to obtaining the high quality chromic oxide green pigment. Typically, when the hydrogen reduction temperature was kept at 450-500 degrees C, physicochemical properties and color performance of the prepared chromic oxide green pigment doped with about 0.1-0.2 wt % Al and 0.2-0.5 wt % Ba conformed to commercial pigment standards. Additionally, characteristics of the green process were discussed. About 90 wt % KOH was reused directly and about 90 wt % Cr(VI) was conversed to Cr(III) directly from potassium chromate to chromic oxide green pigment. Integrating the proprietary green metallurgical process from chromite ore to potassium chromate of this laboratory, more than 99 wt % Cr(VI) could be conversed to Cr(III) compounds and about 99 wt % KOH could be recycled to use. The whole green process, ranging from chromite ore to chromic oxide green pigment, eventually not only provided the possibility for producing the high quality chromic oxide green pigment, but could reach comprehensive utilization of resources, inner recycle of KOH, and zero emission of Cr(VI).

  4. A catalog of putative adverse outcome pathways (AOPs) that will enhance the utility of ToxCast high throughput screening data for hazard identification, delivered via a putative AOP knowledgebase and a ToxCast assay annotation file that can be linked with the iCSS dashboard.

    EPA Science Inventory

    A number of putative AOPs for several distinct MIEs of thyroid disruption have been formulated for amphibian metamorphosis and fish swim bladder inflation. These have been entered into the AOP knowledgebase on the OECD WIKI.

  5. Solid oxide fuel cell process and apparatus

    DOEpatents

    Cooper, Matthew Ellis [Morgantown, WV; Bayless, David J [Athens, OH; Trembly, Jason P [Durham, NC

    2011-11-15

    Conveying gas containing sulfur through a sulfur tolerant planar solid oxide fuel cell (PSOFC) stack for sulfur scrubbing, followed by conveying the gas through a non-sulfur tolerant PSOFC stack. The sulfur tolerant PSOFC stack utilizes anode materials, such as LSV, that selectively convert H.sub.2S present in the fuel stream to other non-poisoning sulfur compounds. The remaining balance of gases remaining in the completely or near H.sub.2S-free exhaust fuel stream is then used as the fuel for the conventional PSOFC stack that is downstream of the sulfur-tolerant PSOFC. A broad range of fuels such as gasified coal, natural gas and reformed hydrocarbons are used to produce electricity.

  6. The role of oxidative processes in emphysema

    SciTech Connect

    Janoff, A.; Carp, H.; Laurent, P.; Raju, L.

    1983-02-01

    Elastase/elastase inhibitor imbalance in the lung has been implicated in the pathogenesis of pulmonary emphysema. In light of this, it may be significant that the activity of two major elastase inhibitors, alpha 1-proteinase inhibitor (alpha 1-antitrypsin, alpha 1Pi) and bronchial mucous proteinase inhibitor, can be decreased by oxidizing agents. The effect can be observed with ozone, substances present in cigarette smoke, and oxygen metabolites generated by lung macrophages as well as peroxidative systems released by other phagocytic cells. Thus alpha 1Pi recovered from lung washings of cigarette smokers has only half the predicted normal activity per mg inhibitor and contains 4 moles of methionine sulfoxide (oxidized methionine) per mole of inactive inhibitor. By contrast, alpha 1Pi purified from nonsmokers' lung washings is fully active and contains only native methionine. At the same time, lung washes from some smokers show significantly greater hydrolytic activity against a specific synthetic elastase substrate than do lung washes of nonsmokers. These findings suggest that some smokers may develop an acquired imbalance between elastase and elastase inhibitor in their lungs, favoring activity of the enzyme. In addition to the potential effect of cigarette smoking on lung elastase/elastase inhibitor balance, smoking also may interfere with elastin repair mechanisms. Specifically, acidic water-soluble gas phase components of cigarette smoke prevent synthesis of desmosine cross-links during elastinogenesis in vitro. This report will attempt to correlate the foregoing information on biochemical changes in the lung induced by cigarette smoking with the development of emphysema in the smoker.

  7. Literature review for oxalate oxidation processes and plutonium oxalate solubility

    SciTech Connect

    Nash, C. A.

    2015-10-01

    A literature review of oxalate oxidation processes finds that manganese(II)-catalyzed nitric acid oxidation of oxalate in precipitate filtrate is a viable and well-documented process. The process has been operated on the large scale at Savannah River in the past, including oxidation of 20 tons of oxalic acid in F-Canyon. Research data under a variety of conditions show the process to be robust. This process is recommended for oxalate destruction in H-Canyon in the upcoming program to produce feed for the MOX facility. Prevention of plutonium oxalate precipitation in filtrate can be achieved by concentrated nitric acid/ferric nitrate sequestration of oxalate. Organic complexants do not appear practical to sequester plutonium. Testing is proposed to confirm the literature and calculation findings of this review at projected operating conditions for the upcoming campaign.

  8. Downscaled anodic oxidation process for aluminium in oxalic acid

    NASA Astrophysics Data System (ADS)

    Sieber, M.; Morgenstern, R.; Kuhn, D.; Hackert-Oschätzchen, M.; Schubert, A.; Lampke, T.

    2017-03-01

    The increasing multi-functionality of parts and assemblies in several fields of engineering demands, amongst others, highly functionalised surfaces. For the different applications, on the one hand, there is a need to scale up surface modification processes originating in the nano- and micro-scale. On the other hand, conventional macro-scale surface refinement methods offer a huge potential for application in the said nano- and micro-scale. The anodic oxidation process, which is established especially for aluminium and its alloys, allows the formation of oxide ceramic layers on the surface. The build-up of an oxide ceramic coating comes along with altered chemical, tribological and electrical surface properties. As a basis for further investigations regarding the use of the anodic oxidation process for micro-scale-manufacturing, the scale effects of oxalic acid anodising on commercially pure aluminium as well as on the AlZn5.5MgCu alloy are addressed in the present work. The focus is on the amount of oxide formed during a potentiostatic process in relation to the exchanged amount of charge. Further, the hardness of the coating as an integral measure to assess the porous oxide structure is approached by nano-indentation technique.

  9. Process for preparing zinc oxide-based sorbents

    DOEpatents

    Gangwal, Santosh Kumar; Turk, Brian Scott; Gupta, Raghubir Prasad

    2011-06-07

    The disclosure relates to zinc oxide-based sorbents, and processes for preparing and using them. The sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents comprise an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, comprising a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

  10. AOP-1 interacts with cardiac-specific protein kinase TNNI3K and down-regulates its kinase activity.

    PubMed

    Feng, Yan; Liu, Dong-Qing; Wang, Zhen; Liu, Zhao; Cao, Hui-Qing; Wang, Lai-Yuan; Shi, Na; Meng, Xian-Min

    2007-11-01

    In the present study, a yeast two-hybrid screening system was used to identify the interaction partners of cardiac troponin I-interacting kinase (TNNI3K) that might serve as regulators or targets, and thus in turn to gain some insights on the roles of TNNI3K. After screening the adult heart cDNA library with a bait construct encoding the ANK motif of TNNI3K, antioxidant protein 1 (AOP-1) was isolated. The interaction between TNNI3K and AOP-1 was confirmed by the in vitro binding assay and coexpression experiments in vivo. The colocalization of TNNI3K and AOP-1 was clarified by confocal immunofluorescence. Moreover, coexpression of AOP-1 inhibited TNNI3K kinase activity in the in vitro kinase assay.

  11. Development studies of a novel wet oxidation process

    SciTech Connect

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

    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.

  12. Oxidation processes in magneto-optic and related materials

    NASA Technical Reports Server (NTRS)

    Lee, Paul A.; Armstrong, Neal R.; Danzinger, James L.; England, Craig D.

    1992-01-01

    The surface oxidation processes of thin films of magneto-optic materials, such as the rare-earth transition metal alloys have been studied, starting in ultrahigh vacuum environments, using surface analysis techniques, as a way of modeling the oxidation processes which occur at the base of a defect in an overcoated material, at the instant of exposure to ambient environments. Materials examined have included FeTbCo alloys, as well as those same materials with low percentages of added elements, such a Ta, and their reactivities to both O2 and H2O compared with materials such as thin Fe films coated with ultrathin adlayers of Ti. The surface oxidation pathways for these materials is reviewed, and XPS data presented which indicates the type of oxides formed, and a critical region of Ta concentration which provides optimum protection.

  13. Development of techniques for processing metal-metal oxide systems

    NASA Technical Reports Server (NTRS)

    Johnson, P. C.

    1976-01-01

    Techniques for producing model metal-metal oxide systems for the purpose of evaluating the results of processing such systems in the low-gravity environment afforded by a drop tower facility are described. Because of the lack of success in producing suitable materials samples and techniques for processing in the 3.5 seconds available, the program was discontinued.

  14. Advanced oxidation processes with coke plant wastewater treatment.

    PubMed

    Krzywicka, A; Kwarciak-Kozłowska, A

    2014-01-01

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

  15. Process of forming catalytic surfaces for wet oxidation reactions

    NASA Technical Reports Server (NTRS)

    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.

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

    PubMed

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

    2014-01-01

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

  17. Air Force Dynamic Mechanical Analysis Testing of NATO Round Robin Propellant Testing for Development of AOP-4717

    DTIC Science & Technology

    2015-08-01

    NATO Round Robin Propellant Testing for Development of AOP-4717 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...provided by Naval Air Warfare Center Weapons Division (NAWCWD). The purpose of the tests was to participate in an international round robin that would...Analysis Testing of NATO Round Robin Propellant Testing for Development of AOP-4717 Timothy C. Miller, Air Force Research Laboratory Patrick N

  18. COLUMBIC OXIDE ADSORPTION PROCESS FOR SEPARATING URANIUM AND PLUTONIUM IONS

    DOEpatents

    Beaton, R.H.

    1959-07-14

    A process is described for separating plutonium ions from a solution of neutron irradiated uranium in which columbic oxide is used as an adsorbert. According to the invention the plutonium ion is selectively adsorbed by Passing a solution containing the plutonium in a valence state not higher than 4 through a porous bed or column of granules of hydrated columbic oxide. The adsorbed plutonium is then desorbed by elution with 3 N nitric acid.

  19. Similarities and differences in RANTES- and (AOP)-RANTES-triggered signals: implications for chemotaxis.

    PubMed

    Rodríguez-Frade, J M; Vila-Coro, A J; Martín, A; Nieto, M; Sánchez-Madrid, F; Proudfoot, A E; Wells, T N; Martínez-A, C; Mellado, M

    1999-02-22

    Chemokines are a family of proinflammatory cytokines that attract and activate specific types of leukocytes. Chemokines mediate their effects via interaction with seven transmembrane G protein-coupled receptors (GPCR). Using CCR5-transfected HEK-293 cells, we show that both the CCR5 ligand, RANTES, as well as its derivative, aminooxypentane (AOP)- RANTES, trigger immediate responses such as Ca2+ influx, receptor dimerization, tyrosine phosphorylation, and Galphai as well as JAK/STAT association to the receptor. In contrast to RANTES, (AOP)-RANTES is unable to trigger late responses, as measured by the association of focal adhesion kinase (FAK) to the chemokine receptor complex, impaired cell polarization required for migration, or chemotaxis. The results are discussed in the context of the dissociation of the late signals, provoked by the chemokines required for cell migration, from early signals.

  20. Similarities and Differences in RANTES- and (AOP)-RANTES–triggered Signals: Implications for Chemotaxis

    PubMed Central

    Rodríguez-Frade, José M.; Vila-Coro, Antonio J.; Martín, Ana; Nieto, Marta; Sánchez-Madrid, Francisco; Proudfoot, Amanda E.I.; Wells, Timothy N.C.; Martínez-A, Carlos; Mellado, Mario

    1999-01-01

    Chemokines are a family of proinflammatory cytokines that attract and activate specific types of leukocytes. Chemokines mediate their effects via interaction with seven transmembrane G protein–coupled receptors (GPCR). Using CCR5-transfected HEK-293 cells, we show that both the CCR5 ligand, RANTES, as well as its derivative, aminooxypentane (AOP)- RANTES, trigger immediate responses such as Ca2+ influx, receptor dimerization, tyrosine phosphorylation, and Gαi as well as JAK/STAT association to the receptor. In contrast to RANTES, (AOP)-RANTES is unable to trigger late responses, as measured by the association of focal adhesion kinase (FAK) to the chemokine receptor complex, impaired cell polarization required for migration, or chemotaxis. The results are discussed in the context of the dissociation of the late signals, provoked by the chemokines required for cell migration, from early signals. PMID:10037796

  1. Air Force Dynamic Mechanical Analysis of NATO Round Robin Propellant Testing for Development of AOP-4717

    DTIC Science & Technology

    2015-09-23

    Round Robin Propellant Testing for Development of AOP-4717 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...area code) N/A Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. 239.18 0 Air Force Dynamic Mechanical Analysis of NATO Round Robin ...the clamps are tight at the coldest temperature. • Long tests such as the frequency sweep sequences prescribed in this round robin may be

  2. The Glucosinolate Biosynthetic Gene AOP2 Mediates Feed-back Regulation of Jasmonic Acid Signaling in Arabidopsis.

    PubMed

    Burow, Meike; Atwell, Susanna; Francisco, Marta; Kerwin, Rachel E; Halkier, Barbara A; Kliebenstein, Daniel J

    2015-08-01

    Survival in changing and challenging environments requires an organism to efficiently obtain and use its resources. Due to their sessile nature, it is particularly critical for plants to dynamically optimize their metabolism. In plant primary metabolism, metabolic fine-tuning involves feed-back mechanisms whereby the output of a pathway controls its input to generate a precise and robust response to environmental changes. By contrast, few studies have addressed the potential for feed-back regulation of secondary metabolism. In Arabidopsis, accumulation of the defense compounds glucosinolates has previously been linked to genetic variation in the glucosinolate biosynthetic gene AOP2. AOP2 expression can increase the transcript levels of two known regulators (MYB28 and MYB29) of the pathway, suggesting that AOP2 plays a role in positive feed-back regulation controlling glucosinolate biosynthesis. We generated mutants affecting AOP2, MYB28/29, or both. Transcriptome analysis of these mutants identified a so far unrecognized link between AOP2 and jasmonic acid (JA) signaling independent of MYB28 and MYB29. Thus, AOP2 is part of a regulatory feed-back loop linking glucosinolate biosynthesis and JA signaling and thereby allows the glucosinolate pathway to influence JA sensitivity. The discovery of this regulatory feed-back loop provides insight into how plants optimize the use of resources for defensive metabolites.

  3. Oxygen vacancy promoted methane partial oxidation over iron oxide oxygen carriers in the chemical looping process.

    PubMed

    Cheng, Zhuo; Qin, Lang; Guo, Mengqing; Xu, Mingyuan; Fan, Jonathan A; Fan, Liang-Shih

    2016-11-30

    We perform ab initio DFT+U calculations and experimental studies of the partial oxidation of methane to syngas on iron oxide oxygen carriers to elucidate the role of oxygen vacancies in oxygen carrier reactivity. In particular, we explore the effect of oxygen vacancy concentration on sequential processes of methane dehydrogenation, and oxidation with lattice oxygen. We find that when CH4 adsorbs onto Fe atop sites without neighboring oxygen vacancies, it dehydrogenates with CHx radicals remaining on the same site and evolves into CO2via the complete oxidation pathway. In the presence of oxygen vacancies, on the other hand, the formed methyl (CH3) prefers to migrate onto the vacancy site while the H from CH4 dehydrogenation remains on the original Fe atop site, and evolves into CO via the partial oxidation pathway. The oxygen vacancies created in the oxidation process can be healed by lattice oxygen diffusion from the subsurface to the surface vacancy sites, and it is found that the outward diffusion of lattice oxygen atoms is more favorable than the horizontal diffusion on the same layer. Based on the proposed mechanism and energy profile, we identify the rate-limiting steps of the partial oxidation and complete oxidation pathways. Also, we find that increasing the oxygen vacancy concentration not only lowers the barriers of CH4 dehydrogenation but also the cleavage energy of Fe-C bonds. However, the barrier of the rate-limiting step cannot further decrease when the oxygen vacancy concentration reaches 2.5%. The fundamental insight into the oxygen vacancy effect on CH4 oxidation with iron oxide oxygen carriers can help guide the design and development of more efficient oxygen carriers and CLPO processes.

  4. Mechanical and tribological properties of oxide layers obtained on titanium in the thermal oxidation process

    NASA Astrophysics Data System (ADS)

    Aniołek, K.; Kupka, M.; Barylski, A.; Dercz, G.

    2015-12-01

    The paper presents the results of tests concerning a modification to the surface of titanium Grade 2 in the thermal oxidation process. It describes the oxidation kinetics of the tested material in the temperature range of 600-800 °C, with a duration from 20 min to 72 h. The greatest increase in mass was found in specimens oxidised at a temperature of 800 °C. The morphology of the obtained oxide layers was determined. The particles of oxides formed were noticeably larger after oxidation at a temperature of 600 °C. Raising temperature resulted in the formation of fine compact particles in the oxide layer. A phase analysis of oxidation products showed that TiO2 in the crystallographic form of rutile and Ti3O are the prevalent types of oxide at a temperature of 600 and 700 °C. On the other hand, only rutile formed at a temperature of 800 °C. Tribological tests showed that the presence of an oxide layer on the surface of titanium significantly improved resistance to abrasive wear. It was found that volumetric wear had decreased by 48% for a specimen oxidised at a temperature of 600 °C and by more than 60% for a specimen subjected to isothermal soaking at a temperature of 700 °C.

  5. Applying Adverse Outcome Pathways (AOPs) to support Integrated Approaches to Testing and Assessment (IATA).

    PubMed

    Tollefsen, Knut Erik; Scholz, Stefan; Cronin, Mark T; Edwards, Stephen W; de Knecht, Joop; Crofton, Kevin; Garcia-Reyero, Natalia; Hartung, Thomas; Worth, Andrew; Patlewicz, Grace

    2014-12-01

    Chemical regulation is challenged by the large number of chemicals requiring assessment for potential human health and environmental impacts. Current approaches are too resource intensive in terms of time, money and animal use to evaluate all chemicals under development or already on the market. The need for timely and robust decision making demands that regulatory toxicity testing becomes more cost-effective and efficient. One way to realize this goal is by being more strategic in directing testing resources; focusing on chemicals of highest concern, limiting testing to the most probable hazards, or targeting the most vulnerable species. Hypothesis driven Integrated Approaches to Testing and Assessment (IATA) have been proposed as practical solutions to such strategic testing. In parallel, the development of the Adverse Outcome Pathway (AOP) framework, which provides information on the causal links between a molecular initiating event (MIE), intermediate key events (KEs) and an adverse outcome (AO) of regulatory concern, offers the biological context to facilitate development of IATA for regulatory decision making. This manuscript summarizes discussions at the Workshop entitled "Advancing AOPs for Integrated Toxicology and Regulatory Applications" with particular focus on the role AOPs play in informing the development of IATA for different regulatory purposes.

  6. Optimization of conventional Fenton and ultraviolet-assisted oxidation processes for the treatment of reverse osmosis retentate from a paper mill.

    PubMed

    Hermosilla, Daphne; Merayo, Noemí; Ordóñez, Ruth; Blanco, Angeles

    2012-06-01

    According to current environmental legislation concerned with water scarcity, paper industry is being forced to adopt a zero liquid effluent policy. In consequence, reverse osmosis (RO) systems are being assessed as the final step of effluent treatment trains aiming to recover final wastewater and reuse it as process water. One of the most important drawbacks of these treatments is the production of a retentated stream, which is usually highly loaded with biorecalcitrant organic matter and inorganics; and this effluent must meet current legislation stringent constraints before being ultimately disposed. The treatment of biorefractory RO retentate from a paper mill by several promising advanced oxidation processes (AOPs) - conventional Fenton, photo-Fenton and photocatalysis - was optimized considering the effect and interaction of reaction parameters; particularly using response surface methodology (RSM) when appropriate (Fenton processes). The economical cost of these treatments was also comparatively assessed. Photo-Fenton process was able to totally remove the COD of the retentate, and resulted even operatively cheaper at high COD removal levels than conventional Fenton, which achieved an 80% reduction of the COD at best. In addition, although these optimal results were produced at pH=2.8, it was also tested that Fenton processes are able to achieve good COD reduction efficiencies (>60%) without adjusting the initial pH value, provided the natural pH of this wastewater was close to neutral. Finally, although TiO(2)-photocatalysis showed the least efficient and most expensive figures, it improved the biodegradability of the retentate, so its combination with a final biological step almost achieved the total removal of the COD.

  7. Microwave processing of ceramic oxide filaments. Annual report, FY1997

    SciTech Connect

    Vogt, G.J.

    1998-12-31

    The objective of the microwave filament processing project is to develop microwave techniques to manufacture continuous ceramic oxide filaments. Microwave processing uses the volumetric absorption of microwave power in oxide filament tows to drive off process solvents, to burn out organic binders, and to sinter the dried fibers to produce flexible, high-strength ceramic filaments. The technical goal is to advance filament processing technology by microwave heating more rapidly with less energy and at a lower cost than conventional processing, but with the same quality as conventional processing. The manufacturing goal is to collaborate with the 3M Company, a US manufacturer of ceramic oxide filaments, to evaluate the technology using a prototype filament system and to transfer the microwave technology to the 3M Company. Continuous ceramic filaments are a principal component in many advanced high temperature materials like continuous fiber ceramic composites (CFCC) and woven ceramic textiles. The use of continuous ceramic filaments in CFCC radiant burners, gas turbines, waste incineration, and hot gas filters in U.S. industry and power generation is estimated to save at least 2.16 quad/yr by year 2010 with energy cost savings of at least $8.1 billion. By year 2010, continuous ceramic filaments and CFCC`s have the potential to abate pollution emissions by 917,000 tons annually of nitrous oxide and 118 million tons annually of carbon dioxide (DOE Report OR-2002, February, 1994).

  8. LITERATURE REVIEW FOR OXALATE OXIDATION PROCESSES AND PLUTONIUM OXALATE SOLUBILITY

    SciTech Connect

    Nash, C.

    2012-02-03

    A literature review of oxalate oxidation processes finds that manganese(II)-catalyzed nitric acid oxidation of oxalate in precipitate filtrate is a viable and well-documented process. The process has been operated on the large scale at Savannah River in the past, including oxidation of 20 tons of oxalic acid in F-Canyon. Research data under a variety of conditions show the process to be robust. This process is recommended for oxalate destruction in H-Canyon in the upcoming program to produce feed for the MOX facility. Prevention of plutonium oxalate precipitation in filtrate can be achieved by concentrated nitric acid/ferric nitrate sequestration of oxalate. Organic complexants do not appear practical to sequester plutonium. Testing is proposed to confirm the literature and calculation findings of this review at projected operating conditions for the upcoming campaign. H Canyon plans to commence conversion of plutonium metal to low-fired plutonium oxide in 2012 for eventual use in the Mixed Oxide Fuel (MOX) Facility. The flowsheet includes sequential operations of metal dissolution, ion exchange, elution, oxalate precipitation, filtration, and calcination. All processes beyond dissolution will occur in HB-Line. The filtration step produces an aqueous filtrate that may have as much as 4 M nitric acid and 0.15 M oxalate. The oxalate needs to be removed from the stream to prevent possible downstream precipitation of residual plutonium when the solution is processed in H Canyon. In addition, sending the oxalate to the waste tank farm is undesirable. This report addresses the processing options for destroying the oxalate in existing H Canyon equipment.

  9. Process for combined control of mercury and nitric oxide.

    SciTech Connect

    Livengood, C. D.; Mendelsohn, M. H.

    1999-11-03

    Continuing concern about the effects of mercury in the environment may lead to requirements for the control of mercury emissions from coal-fired power plants. If such controls are mandated, the use of existing flue-gas cleanup systems, such as wet scrubbers currently employed for flue-gas desulfurization, would be desirable, Such scrubbers have been shown to be effective for capturing oxidized forms of mercury, but cannot capture the very insoluble elemental mercury (Hg{sup 0}) that can form a significant fraction of the total emissions. At Argonne National Laboratory, we have proposed and tested a concept for enhancing removal of Hg{sup 0}, as well as nitric oxide, through introduction of an oxidizing agent into the flue gas upstream of a scrubber, which readily absorbs the soluble reaction products. Recently, we developed a new method for introducing the oxidizing agent into the flue-gas stream that dramatically improved reactant utilization. The oxidizing agent employed was NOXSORB{trademark}, which is a commercial product containing chloric acid and sodium chlorate. When a dilute solution of this agent was introduced into a gas stream containing Hg{sup 0} and other typical flue-gas species at 300 F, we found that about 100% of the mercury was removed from the gas phase and recovered in process liquids. At the same time, approximately 80% of the nitric oxide was removed. The effect of sulfur dioxide on this process was also investigated and the results showed that it slightly decreased the amount of Hg{sup 0} oxidized while appearing to increase the removal of nitric oxide from the gas phase. We are currently testing the effects of variations in NOXSORB{trademark} concentration, sulfur dioxide concentration, nitric oxide concentration, and reaction time (residence time). Preliminary economic projections based on the results to date indicate that the chemical cost for nitric oxide oxidation could be less than $5,000/ton removed, while for Hg{sup 0} oxidation it

  10. Nitrogen removal with the anaerobic ammonium oxidation process.

    PubMed

    Hu, Ziye; Lotti, Tommaso; van Loosdrecht, Mark; Kartal, Boran

    2013-08-01

    Anaerobic ammonium-oxidizing (anammox) bacteria convert ammonium to N2 with nitrite as the terminal electron acceptor in the absence of O2. Nitritation-anammox bioreactors provide a cost-effective and environment-friendly alternative to conventional nitrification/denitrification nitrogen removal systems. Currently, this process is only applied for ammonium removal from wastewater with high ammonium load and temperature. Nevertheless, recent results obtained with laboratory-scale bioreactors suggest new possible routes of application of the Nitritation-anammox technology including (1) municipal wastewater treatment, removal of (2) methane in combination with nitrite-reducing methane-oxidizing bacteria, (3) nitrate coupled to organic acid oxidation and (4) nitrogen oxides. The current review summarizes the state-of-the-art of the application of Nitritation-anammox systems and discusses the possibilities of utilizing these recent results for wastewater treatment.

  11. UV/Fenton photo-oxidation of Drimarene Dark Red (DDR) containing textile-dye wastewater

    NASA Astrophysics Data System (ADS)

    Hudaya, T.; Anthonios, J.; Septianto, E.

    2016-11-01

    Textile dye wastewater contains organic pollutants which are non-biodegradable, characterized by low BOD/COD ratio of typically < 0.01. Therefore to treat such wastewater, the destructive wastewater treatment methods which can be utilized are the Advanced Oxidation Processes (AOPs). One of the AOPs method which is the UV/H2O2/Fe2+ (or UV/Fenton) offers not only relatively low cost but also quite effective (in terms of color removal and reaction time) treatment. This particular research aimed to optimize the conditions of UV/Fenton photo-oxidation process for Drimarene Dark Red containing textile- dye wastewater. The two main operating conditions to be optimized were the initial concentration of H2O2 ranged between 0.022-0.078 %-w and the mol ratio of Fe2+: H2O2 was varied from 1: 13 up to 1: 45, using the Central Composite Design experimental matrix. The photo-oxidation was carried out at the optimum pH of 3 from some previous experiments. The best processing conditions of the photo-oxidation of Drimarene Dark Red (DDR) were found at the initial concentration of H2O2 at 0.050%-w and the mole ratio Fe2+: H2O2 of 1: 22. Under these conditions, the measured 2nd order pseudo-rate constantwas 0.021 M-1.min-1. The DDR color removal of 90% was surprisingly achievable within only 10 minutes reaction time.

  12. Oxidation of acetovanillone by photochemical processes and hydroxyl radicals.

    PubMed

    Benitez, F Javier; Real, Francisco J; Acero, Juan L; Leal, Ana I; Cotilla, Sonia

    2005-01-01

    Acetovanillone [Ethanone, 1-(4-hydroxy-3-metoxyphenyl)] is one of the major pollutants that is present in the wastewater produced during the boiling of raw material in the cork industry. The oxidation of its aqueous solutions by monochromatic UV radiation alone and combined with hydrogen peroxide, Fenton's reagent and the photo-Fenton system has been investigated. In the single UV radiation process, the apparent rate constants and the quantum yields are determined, and in the UV/H2O2 combination, the additional efficiency in the oxidation process due to the presence of hydrogen peroxide is established. The influence of some operating variables, such as initial concentrations of H2O2 and Fe(II), as well as the pH, is discussed in the Fenton and photo-Fenton systems, and the partial contribution of the radical pathways to the global oxidation rates are evaluated. The rate constant for the reaction of acetovanillone with hydroxyl radicals is also determined by means of a competition kinetics model, its value being 5.62 x 10(9) M(-1)s(-1). Finally, chemical oxidation experiments of wastewaters generated in this industry were carried out by using the same advanced oxidation processes. Specifically, the elimination of acetovanillone in these effluents was determined, and the removal of the global organic pollutant content was also evaluated.

  13. Effects of arginine on hair damage via oxidative coloring process.

    PubMed

    Oshimura, Eiko; Ino, Masahiro

    2004-01-01

    The purpose of this study was to measure the protective effects of arginine in oxidative coloring or bleaching process. Contact angle measurement, tensile measurement and amino acid analysis were employed. As the first step, it was shown that oxidative coloring or bleaching process decreases hair surface hydrophobicity and tensile strength in wet condition. Next the study has been conducted with coloring agents in which part of the ammonia was replaced with arginine, to find that arginine reduced the oxidative change in contact angle and tensile strength. These results suggest that arginine prevents the undesirable attack by hydrogen peroxide on hair proteins and hair surface lipids. Furthermore, it is also suggested from amino acid analysis that a considerable amount of arginine is deposited on, or in hair fibers from coloring agents.

  14. Application of metabolite profiling tools and time-of-flight mass spectrometry in the identification of transformation products of iopromide and iopamidol during advanced oxidation.

    PubMed

    Singh, Randolph R; Lester, Yaal; Linden, Karl G; Love, Nancy G; Atilla-Gokcumen, G Ekin; Aga, Diana S

    2015-03-03

    The efficiency of wastewater treatment systems in removing pharmaceuticals is often assessed on the basis of the decrease in the concentration of the parent compound. However, what is perceived as "removal" during treatment may not necessarily mean mineralization of the pharmaceutical compound but simply conversion into different transformation products (TPs). Using liquid chromatography coupled to a quadrupole time-of-flight mass spectrometer (LC-QToF-MS), we demonstrated conversion of iopromide in wastewater to at least 14 TPs after an advanced oxidation process (AOP) using UV (fluence = 1500 mJ/cm(2)) and H2O2 (10 mg/L). Due to the complexity of the wastewater matrix, the initial experiments were performed using a high concentration (10 mg/L) of iopromide in order to facilitate the identification of TPs. Despite the high concentration of iopromide used, cursory inspection of UV and mass spectra only revealed four TPs in the chromatograms of the post-AOP samples. However, the use of METLIN database and statistics-based profiling tools commonly used in metabolomics proved effective in discriminating between background signals and TPs derived from iopromide. High-resolution mass data allowed one to predict molecular formulas of putative TPs with errors below 5 ppm relative to the observed m/z. Tandem mass spectrometry (MS/MS) data and isotope pattern comparisons provided necessary information that allowed one to elucidate the structure of iopromide TPs. The presence of the proposed iopromide TPs was determined in unspiked wastewater from a municipal wastewater treatment plant, but no iopromide and TPs were detected. Using analogous structural modifications and oxidation that results from the AOP treatment of iopromide, the potential TPs of iopamidol (a structurally similar compound to iopromide) were predicted. The same mass fragmentation pattern observed in iopromide TPs was applied to the predicted iopamidol TPs. LC-QToF-MS revealed the presence of two iopamidol

  15. Treatment of door-manufacturing factories wastewaters using CDEO and other AOPs: a comparison.

    PubMed

    Beteta, Alberto; Cañizares, Pablo; Rodrigo, Manuel A; Rodríguez, Lourdes; Sáez, Cristina

    2009-08-30

    In this work, three advanced oxidation technologies have been studied to improve the quality of the effluents of a physicochemical process and of a combined physicochemical-biological process during the treatment of actual industrial wastes of wooden door-manufacturing factories. From the treatment point of view (neglecting costs), advanced oxidation processes can be successfully used to treat both, coagulated and biologically treated wastes. Conductive-diamond electrochemical oxidation (CDEO) was found to be the more effective technology because it can reduce completely the chemical oxygen demand (COD) (no production of refractory compounds) with a very high current efficiency. However, from the economic viewpoint, the direct treatment of the coagulated wastes can not be recommended because it is very expensive. Only Fenton oxidation or conductive-diamond electrochemical oxidation can be cost-efficiently used to refine the quality of the effluent of the biological process.

  16. GREENING OF OXIDATION CATALYSIS THROUGH IMPROVED CATALYST AND PROCESS DESIGN

    EPA Science Inventory


    Greening of Oxidation Catalysis Through Improved Catalysts and Process Design
    Michael A. Gonzalez*, Thomas Becker, and Raymond Smith

    United State Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 W...

  17. Better End-Cap Processing for Oxidation-Resistant Polyimides

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.; Frimer, Aryeh A.

    2004-01-01

    A class of end-cap compounds that increase the thermo-oxidative stab ility of polyimides of the polymerization of monomeric reactants (PM R) type has been extended. In addition, an improved processing proto col for this class of end-cap compounds has been invented.

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

    PubMed

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

    2014-01-01

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

  19. Removal of ammonia solutions used in catalytic wet oxidation processes.

    PubMed

    Hung, Chang Mao; Lou, Jie Chung; Lin, Chia Hua

    2003-08-01

    Ammonia (NH(3)) is an important product used in the chemical industry, and is common place in industrial wastewater. Industrial wastewater containing ammonia is generally either toxic or has concentrations or temperatures such that direct biological treatment is unfeasible. This investigation used aqueous solutions containing more of ammonia for catalytic liquid-phase oxidation in a trickle-bed reactor (TBR) based on Cu/La/Ce composite catalysts, prepared by co-precipitation of Cu(NO(3))(2), La(NO(3))(2), and Ce(NO(3))(3) at 7:2:1 molar concentrations. The experimental results indicated that the ammonia conversion of the wet oxidation in the presence of the Cu/La/Ce composite catalysts was determined by the Cu/La/Ce catalyst. Minimal ammonia was removed from the solution by the wet oxidation in the absence of any catalyst, while approximately 91% ammonia removal was achieved by wet oxidation over the Cu/La/Ce catalyst at 230 degrees C with oxygen partial pressure of 2.0 MPa. Furthermore, the effluent streams were conducted at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes, and a reaction pathway was found linking the oxidizing ammonia to nitric oxide, nitrogen and water. The solution contained by-products, including nitrates and nitrites. Nitrite selectivity was minimized and ammonia removal maximized when the feed ammonia solution had a pH of around 12.0.

  20. Thermal imaging of solid oxide fuel cell anode processes

    NASA Astrophysics Data System (ADS)

    Pomfret, Michael B.; Steinhurst, Daniel A.; Kidwell, David A.; Owrutsky, Jeffrey C.

    A Si-charge-coupled device (CCD), camera-based, near-infrared imaging system is demonstrated on Ni/yttria-stabilized zirconia (YSZ) fragments and the anodes of working solid oxide fuel cells (SOFCs). NiO reduction to Ni by H 2 and carbon deposition lead to the fragment cooling by 5 ± 2 °C and 16 ± 1 °C, respectively. When air is flowed over the fragments, the temperature rises 24 ± 1 °C as carbon and Ni are oxidized. In an operational SOFC, the decrease in temperature with carbon deposition is only 4.0 ± 0.1 °C as the process is moderated by the presence of oxides and water. Electrochemical oxidation of carbon deposits results in a Δ T of +2.2 ± 0.2 °C, demonstrating that electrochemical oxidation is less vigorous than atmospheric oxidation. While the high temperatures of SOFCs are challenging in many respects, they facilitate thermal imaging because their emission overlaps the spectral response of inexpensive Si-CCD cameras. Using Si-CCD cameras has advantages in terms of cost, resolution, and convenience compared to mid-infrared thermal cameras. High spatial (∼0.1 mm) and temperature (∼0.1 °C) resolutions are achieved in this system. This approach provides a convenient and effective analytical technique for investigating the effects of anode chemistry in operating SOFCs.

  1. Design and processing of all-oxide composites

    SciTech Connect

    Lundberg, R.; Eckerbom, L.

    1995-12-01

    All-oxide ceramic composites as a material with potential for long life-time applications at temperatures in the 1400-1600{degrees}C range in combustion environments were studied. The properties of available polycrystalline and single crystal oxide fibres were summarised. The literature on stable weak interfaces in all-oxide composites was reviewed. Composites with single crystal fibres, a polycrystalline matrix of the same material as the fibres, and a compatible high temperature stable weak oxide interphase was suggested to be the most promising approach. Processing of all-oxide composites was performed. ZrO{sub 2}-coated sapphire fibres in reaction bonded alumina and in hot pressed alumina showed crack deflection and fibre pull-out. In reaction bonded mullite crack deflection and pull-out was observed even for un-coated sapphire fibres. This was attributed to thermal expansion mismatch. A recently started European project aiming at development, scale-up and property evaluation of all-oxide composites is briefly outlined.

  2. Process and Equipment for Nitrogen Oxide Waste Conversion to Fertilizer

    NASA Technical Reports Server (NTRS)

    Lueck, Dale E. (Inventor); Parrish, Clyde F. (Inventor)

    2000-01-01

    The present invention describes a process for converting vapor streams from sources containing at least one nitrogen-containing oxidizing agent therein to a liquid fertilizer composition comprising the steps of: (1) directing a vapor stream containing at least nitrogen-containing oxidizing agent to a first contact zone; (2) contacting said vapor stream with water to form nitrogen oxide(s) from said at least one nitrogen- containing oxidizing agent; (3) directing said acid(s) as a second stream to a second contact zone; (4) exposing said second stream to hydrogen peroxide which is present within said second contact zone in a relative amount of at least 0.1% by weight of said second stream within said second contact zone to convert at least some of any nitrogen oxide species or ions other than in the nitrite form present within said second stream to nitrate ion; (5) sampling said stream within said second contact zone to determine the relative amount of hydrogen peroxide within said second contact zone; (6) adding hydrogen peroxide to said second contact zone when a level on hydrogen peroxide less than 0.1% by weight in said second stream is determined by said sampling; (7) adding a solution comprising potassium hydroxide to said second stream to maintain a pH between 6.0 and 11.0 within said second stream within said second contact zone to form a solution of potassium nitrate; and (8) removing sais solution of potassium nitrate from said second contact zone.

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

    SciTech Connect

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

    1990-01-01

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

  4. Development studies of a novel wet oxidation process

    SciTech Connect

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

    1995-12-01

    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. 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.

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

    PubMed

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

    2008-04-01

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

  6. Conceptual Design for the Pilot-Scale Plutonium Oxide Processing Unit in the Radiochemical Processing Laboratory

    SciTech Connect

    Lumetta, Gregg J.; Meier, David E.; Tingey, Joel M.; Casella, Amanda J.; Delegard, Calvin H.; Edwards, Matthew K.; Jones, Susan A.; Rapko, Brian M.

    2014-08-05

    This report describes a conceptual design for a pilot-scale capability to produce plutonium oxide for use as exercise and reference materials, and for use in identifying and validating nuclear forensics signatures associated with plutonium production. This capability is referred to as the Pilot-scale Plutonium oxide Processing Unit (P3U), and it will be located in the Radiochemical Processing Laboratory at the Pacific Northwest National Laboratory. The key unit operations are described, including plutonium dioxide (PuO2) dissolution, purification of the Pu by ion exchange, precipitation, and conversion to oxide by calcination.

  7. Integration between chemical oxidation and membrane thermophilic biological process.

    PubMed

    Bertanza, G; Collivignarelli, M C; Crotti, B M; Pedrazzani, R

    2010-01-01

    Full scale applications of activated sludge thermophilic aerobic process for treatment of liquid wastes are rare. This experimental work was carried out at a facility, where a thermophilic reactor (1,000 m(3) volume) is operated. In order to improve the global performance of the plant, it was decided to upgrade it, by means of two membrane filtration units (ultrafiltration -UF-, in place of the final sedimentation, and nanofiltration -NF-). Subsequently, the integration with chemical oxidation (O(3) and H(2)O(2)/UV processes) was taken into consideration. Studied solutions dealt with oxidation of both the NF effluents (permeate and concentrate). Based on experimental results and economic evaluation, an algorithm was proposed for defining limits of convenience of this process.

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

    PubMed

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

    2002-02-01

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

  9. Hybridization of natural systems with advanced treatment processes for organic micropollutant removals: new concepts in multi-barrier treatment.

    PubMed

    Sudhakaran, Sairam; Maeng, Sung Kyu; Amy, Gary

    2013-07-01

    Organic micropollutants (OMPs) represent a major constraint in drinking water supply. In the past, emphasis has been on individual treatment processes comprising conventional treatment (coagulation, sedimentation, and filtration) followed by advanced treatment processes (adsorption, ion-exchange, oxidation, and membrane separation). With the depletion of water resources and high demand for power and chemical usage, efforts need to be made to judiciously use advanced treatment processes. There is a new interest in multiple barriers with synergies in which two coupled processes can function as a hybrid process. Within the context of this paper, the hybrid processes include a natural treatment process coupled with an advanced process. Pilot/full-scale studies have shown efficient removal of OMPs by these hybrid processes. With this hybridization, the usage of resources such as power and chemicals can be reduced. In this study, coupling/hybridization of aquifer recharge and recovery (ARR) with oxidation (O3), advanced oxidation process which involves OH radicals (AOP), nanofiltration (NF), reverse osmosis (RO) and granular activated carbon (GAC) adsorption for OMP removal was studied. O3 or AOP as a pre-treatment and GAC, NF, RO, or UV/chlorination as a post-treatment to ARR was studied. NF can be replaced by RO for removal of OMPs since studies have shown similar performance of NF to RO for removal of many OMPs, thereby reducing costs and providing a more sustainable approach.

  10. Advanced oxidation processes in azo dye wastewater treatment.

    PubMed

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

    2006-06-01

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

  11. Development studies for a novel wet oxidation process

    SciTech Connect

    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.

  12. The development model of software product line based AOP

    NASA Astrophysics Data System (ADS)

    Yin, JingHai

    2011-10-01

    In this paper, we proposed a development model of MIS (management information system) software based aspect-oriented programming. MIS software will be the full separation of concerns, and establish corresponding platform-independent model, the dynamic weaving of aspects does not require all the static or fixed in weaver weaving in specific areas and at the same time Optimization, reducing system complexity and improve software development efficiency and speed. While the description and implementation of all aspects of the software industry chain assigned to the various levels of development team to complete, MIS can help resolve the current heavy workload of the software development process, low developing level, low software reuse rate, more duplication work of effort Problems.

  13. Landfill leachate treatment by solar-driven AOPs

    SciTech Connect

    Rocha, Elisangela M.R.; Vilar, Vitor J.P.; Boaventura, Rui A.R.; Fonseca, Amelia; Saraiva, Isabel

    2011-01-15

    Sanitary landfill leachate resulting from the rainwater percolation through the landfill layers and waste material decomposition is a complex mixture of high-strength organic and inorganic compounds which constitutes serious environmental problems. In this study, different heterogeneous (TiO{sub 2}/UV, TiO{sub 2}/H{sub 2}O{sub 2}/UV) and homogenous (H{sub 2}O{sub 2}/UV, Fe{sup 2+}/H{sub 2}O{sub 2}/UV) photocatalytic processes were investigated as an alternative for the treatment of a mature landfill leachate. The addition of H{sub 2}O{sub 2} to TiO{sub 2}/UV system increased the reduction of the aromatic compounds from 15% to 61%, although mineralization was almost the same. The DOC and aromatic content abatement is similar for the H{sub 2}O{sub 2}/UV and TiO{sub 2}/H{sub 2}O{sub 2}/UV processes, although the H{sub 2}O{sub 2} consumption is three times higher in the H{sub 2}O{sub 2}/UV system. The low efficiency of TiO{sub 2}/H{sub 2}O{sub 2}/UV system is presumably due to the alkaline leachate solution, for which the H{sub 2}O{sub 2} becomes highly unstable and self-decomposition of H{sub 2}O{sub 2} occurs. The efficiency of the TiO{sub 2}/H{sub 2}O{sub 2}/UV system increased 10 times after a preliminary pH correction to 4. The photo-Fenton process is much more efficient than heterogeneous (TiO{sub 2}, TiO{sub 2}/H{sub 2}O{sub 2}/UV) or homogeneous (H{sub 2}O{sub 2}/UV) photocatalysis, showing an initial reaction rate more than 20 times higher, and leading to almost complete mineralization of the wastewater. However, when compared with TiO{sub 2}/H{sub 2}O{sub 2}/UV with acidification, the photo-Fenton reaction is only two times faster. The optimal initial iron dose for the photo-Fenton treatment of the leachate is 60 mg Fe{sup 2+} L{sup -1}, which is in agreement with path length of 5 cm in the photoreactor. The kinetic behaviour of the process (60 mg Fe{sup 2+} L{sup -1}) comprises a slow initial reaction, followed by a first-order kinetics (k = 0.020 LkJ{sub UV

  14. Solution processed metal oxide thin film hole transport layers for high performance organic solar cells

    DOEpatents

    Steirer, K. Xerxes; Berry, Joseph J.; Chesin, Jordan P.; Lloyd, Matthew T.; Widjonarko, Nicodemus Edwin; Miedaner, Alexander; Curtis, Calvin J.; Ginley, David S.; Olson, Dana C.

    2017-01-10

    A method for the application of solution processed metal oxide hole transport layers in organic photovoltaic devices and related organic electronics devices is disclosed. The metal oxide may be derived from a metal-organic precursor enabling solution processing of an amorphous, p-type metal oxide. An organic photovoltaic device having solution processed, metal oxide, thin-film hole transport layer.

  15. Activation of human macrophages by allogeneic islets preparations: inhibition by AOP-RANTES and heparinoids.

    PubMed

    Sigrist, Séverine; Oberholzer, José; Bohbot, Alain; Esposito, Guy; Mandes, Karim; Lamartine, Roger; Toso, Christian; Bucher, Pascal; Pinget, Michel; Kessler, Laurence

    2004-04-01

    During transplantation, pancreatic islets release chemokines which promote macrophage attraction, hampering engraftment of islets. The aim of this study was to modulate chemotaxis and the immune response of human macrophages induced by islets. Human monocyte-derived macrophages of healthy subjects were exposed to supernatants of human islets. Chemotaxis, tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) release were evaluated. To modulate migration, human macrophages were incubated in the presence of aminooxypentane-regulated on activation, normal, T-cell expressed, and secreted (AOP-RANTES), a potent antagonist of CCR5. Chemotactic activity of islets supernatant was modulated by the addition of heparin or heparinoids [pentosan and calix[8S]arene (C8S)]. AOP-RANTES significantly reduced, in a dose-dependent manner, macrophage chemotaxis and cytokine release induced by islets supernatant. The chemotactic index was reduced from 3.05 +/- 0.27 to 0.71 +/- 12, TNF-alpha from 1205 +/- 52 to 202 +/- 12 pg/ml, and IL-1beta from 234 +/- 12 to 10 +/- 6 pg/ml. The trapping of chemokines by heparinoids reduced the chemotactic activity of islets supernatant from 3.05 +/- 0.27 to 1.2 +/- 0.1 with heparin or pentosan and to 1.72 +/- 0.22 with C8S, and also decreased the TNF-alpha release by human macrophages from 1205 +/- 35 to 1000 +/- 26 (C8S), 250 +/- 21 (heparin) and 320 +/- 19 (pentosan) pg/ml, and IL-1beta from 234 +/- 13 to 151 +/- 5 (C8S), 50 +/- 3 (heparin) and 57 +/- 4 (pentosan) pg/ml. In conclusion, AOP-RANTES and heparinoids inhibit human macrophage activation and migration induced by islets supernatant.

  16. Activation of human macrophages by allogeneic islets preparations: inhibition by AOP-RANTES and heparinoids

    PubMed Central

    Sigrist, Séverine; Oberholzer, José; Bohbot, Alain; Esposito, Guy; Mandes, Karim; Lamartine, Roger; Toso, Christian; Bucher, Pascal; Pinget, Michel; Kessler, Laurence

    2004-01-01

    During transplantation, pancreatic islets release chemokines which promote macrophage attraction, hampering engraftment of islets. The aim of this study was to modulate chemotaxis and the immune response of human macrophages induced by islets. Human monocyte-derived macrophages of healthy subjects were exposed to supernatants of human islets. Chemotaxis, tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) release were evaluated. To modulate migration, human macrophages were incubated in the presence of aminooxypentane-regulated on activation, normal, T-cell expressed, and secreted (AOP-RANTES), a potent antagonist of CCR5. Chemotactic activity of islets supernatant was modulated by the addition of heparin or heparinoids [pentosan and calix[8S]arene (C8S)]. AOP-RANTES significantly reduced, in a dose-dependent manner, macrophage chemotaxis and cytokine release induced by islets supernatant. The chemotactic index was reduced from 3·05 ± 0·27 to 0·71 ± 12, TNF-α from 1205 ± 52 to 202 ± 12 pg/ml, and IL-1β from 234 ± 12 to 10 ± 6 pg/ml. The trapping of chemokines by heparinoids reduced the chemotactic activity of islets supernatant from 3·05 ± 0·27 to 1·2 ± 0·1 with heparin or pentosan and to 1·72 ± 0·22 with C8S, and also decreased the TNF-α release by human macrophages from 1205 ± 35 to 1000 ± 26 (C8S), 250 ± 21 (heparin) and 320 ± 19 (pentosan) pg/ml, and IL-1β from 234 ± 13 to 151 ± 5 (C8S), 50 ± 3 (heparin) and 57 ± 4 (pentosan) pg/ml. In conclusion, AOP-RANTES and heparinoids inhibit human macrophage activation and migration induced by islets supernatant. PMID:15056378

  17. Mobilization Protocols for Hybrid Sensors for Environmental AOP Sampling (HySEAS) Observations

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B.

    2014-01-01

    The protocols presented here enable the proper mobilization of the latest-generation instruments for measuring the apparent optical properties (AOPs) of aquatic ecosystems. The protocols are designed for the Hybrid Sensors for Environmental AOP Sampling (HySEAS) class of instruments, but are applicable to the community of practice for AOP measurements. The protocols are organized into eleven sections beyond an introductory overview: a) cables and connectors, b) HySEAS instruments, c) platform preparation, d) instrument installation, e) cable installation, f) test deployment, g) test recovery, h) maintenance, i) shipping, j) storage, and k) smallboat operations. Each section concentrates on documenting how to prevent the most likely faults, remedy them should they occur, and accomplishing both with the proper application of a modest set of useful tools. Within the twelve sections, there are Socratic exercises to stimulate thought, and the answers to these exercises appear in Appendix A. Frequently asked questions (FAQs) are summarized in a separate section after the answers to the exercises in Appendix B. For practitioners unfamiliar with the nautical terms used throughout this document plus others likely encountered at sea, an abbreviated dictionary of nautical terms appears in Appendix C. An abbreviated dictionary of radiotelephone terms is presented in Appendix D. To ensure familiarity with many of the tools that are presented, Appendix E provides a description of the tools alongside a thumbnail picture. Abbreviated deployment checklists and cable diagrams are provided in Appendix F. The document concludes with an acknowledgments section, a glossary of acronyms, a definition of symbols, and a list of references.

  18. Fracture process of nonstoichiometric oxide based solid oxide fuel cell under oxidizing/reducing gradient conditions

    NASA Astrophysics Data System (ADS)

    Sato, Kazuhisa; Yashiro, Keiji; Kawada, Tatsuya; Yugami, Hiroo; Hashida, Toshiyuki; Mizusaki, Junichiro

    The influence of chemically induced expansion on the fracture damage of a nonstoichiometric oxide (ceria) based solid oxide fuel cell (SOFC) single cell laminate was investigated by using numerical stress analyses under oxidizing/reducing gradient condition. The single cell examined in this study was composed of electrolyte (Ce 0.8Sm 0.2O 2- δ), anode (Cermets of Ni-Ce 0.8Sm 0.2O 2- δ), and cathode (La 0.6Sr 0.4Co 0.2Fe 0.8O 3- δ), respectively. The finite element method (FEM) was employed to calculate the residual stress, thermal stresses, and chemically induced expansion stresses for the single cell. The residual and thermal stresses were calculated much smaller than the fracture strength of the individual components of the single cell. On the other hand, the chemically induced expansion stresses were shown to remarkably increase for the temperature range greater than 973 K and accounted their magnitude for primary part of the induced stress. It was shown from the FEM that the maximum circumferential stress induced in the single cell exceeded the fracture strength of the individual components at the onset of the fracture damage detect by acoustic emission (AE) method.

  19. Lewis acid catalysis and Green oxidations: sequential tandem oxidation processes induced by Mn-hyperaccumulating plants.

    PubMed

    Escande, Vincent; Renard, Brice-Loïc; Grison, Claude

    2015-04-01

    Among the phytotechnologies used for the reclamation of degraded mining sites, phytoextraction aims to diminish the concentration of polluting elements in contaminated soils. However, the biomass resulting from the phytoextraction processes (highly enriched in polluting elements) is too often considered as a problematic waste. The manganese-enriched biomass derived from native Mn-hyperaccumulating plants of New Caledonia was presented here as a valuable source of metallic elements of high interest in chemical catalysis. The preparation of the catalyst Eco-Mn1 and reagent Eco-Mn2 derived from Grevillea exul exul and Grevillea exul rubiginosa was investigated. Their unusual polymetallic compositions allowed to explore new reactivity of low oxidative state of manganese-Mn(II) for Eco-Mn1 and Mn(IV) for Eco-Mn2. Eco-Mn1 was used as a Lewis acid to catalyze the acetalization/elimination of aldehydes into enol ethers with high yields; a new green and stereoselective synthesis of (-)-isopulegol via the carbonyl-ene cyclization of (+)-citronellal was also performed with Eco-Mn1. Eco-Mn2 was used as a mild oxidative reagent and controlled the oxidation of aliphatic alcohols into aldehydes with quantitative yields. Oxidative cleavage was interestingly noticed when Eco-Mn2 was used in the presence of a polyol. Eco-Mn2 allowed direct oxidative iodination of ketones without using iodine, which is strongly discouraged by new environmental legislations. Finally, the combination of the properties in the Eco-Mn catalysts and reagents gave them an unprecedented potential to perform sequential tandem oxidation processes through new green syntheses of p-cymene from (-)-isopulegol and (+)-citronellal; and a new green synthesis of functionalized pyridines by in situ oxidation of 1,4-dihydropyridines.

  20. Process for growing a film epitaxially upon an oxide surface and structures formed with the process

    DOEpatents

    McKee, Rodney Allen; Walker, Frederick Joseph

    1998-01-01

    A process and structure wherein a film comprised of a perovskite or a spinel is built epitaxially upon a surface, such as an alkaline earth oxide surface, involves the epitaxial build up of alternating constituent metal oxide planes of the perovskite or spinel. The first layer of metal oxide built upon the surface includes a metal element which provides a small cation in the crystalline structure of the perovskite or spinel, and the second layer of metal oxide built upon the surface includes a metal element which provides a large cation in the crystalline structure of the perovskite or spinel. The layering sequence involved in the film build up reduces problems which would otherwise result from the interfacial electrostatics at the first atomic layers, and these oxides can be stabilized as commensurate thin films at a unit cell thickness or grown with high crystal quality to thicknesses of 0.5-0.7 .mu.m for optical device applications.

  1. Process for growing a film epitaxially upon an oxide surface and structures formed with the process

    DOEpatents

    McKee, Rodney A.; Walker, Frederick J.

    1995-01-01

    A process and structure wherein a film comprised of a perovskite or a spinel is built epitaxially upon a surface, such as an alkaline earth oxide surface, involves the epitaxial build up of alternating constituent metal oxide planes of the perovskite or spinel. The first layer of metal oxide built upon the surface includes a metal element which provides a small cation in the crystalline structure of the perovskite or spinel, and the second layer of metal oxide built upon the surface includes a metal element which provides a large cation in the crystalline structure of the perovskite or spinel. The layering sequence involved in the film build up reduces problems which would otherwise result from the interfacial electrostatics at the first atomic layers, and these oxides can be stabilized as commensurate thin films at a unit cell thickness or grown with high crystal quality to thicknesses of 0.5-0.7 .mu.m for optical device applications.

  2. Process for the reduction of nitrogen oxides in an effluent

    SciTech Connect

    Epperly, W.R.; Sullivan, J.C.

    1988-09-13

    A process is described for reducing the concentration of nitrogen oxides in an effluent from the combustion of a carbonaceous fuel, which process comprises injecting into the effluent ammonia and an enhancer selected from the group consisting of hexamethylenetetramine, a lower carbon alcohol, a hydroxyl amino hydrocarbon, sugar, furfural, furfural derivatives, an amino acid, a protein-containing composition, mixtures of ortho-, meta-, and para-methyl phenols, guanidine, guanidine carbonate, biguanidine, guanylurea sulfate, melamine, dicyandiamide, calcium cyanamide, biuret, 1,1'-azobisformamide, methylol urea, methylol urea-urea condensation product, dimethylol urea, methyl urea, dimethyl urea, and mixtures thereof, at an effluent temperature above about 1300/sup 0/F and a molar ratio of nitrogen in the ammonia and enhancer to the baseline nitrogen oxides level of about 1:5 to about 6:1 wherein the excess of oxygen in the effluent is no greater than about 6%.

  3. Treatment of sewage sludge in a continuous-flow radiofrequency-oxidation system.

    PubMed

    Lo, Kwang V; Srinivasan, Asha; Liao, Ping H

    2017-04-01

    This study explored the applicability of a pilot-scale continuous-flow radiofrequency (RF) heating system to treat sewage sludge by the RF-oxidation process (RF/H2O2). Depending on temperature and hydrogen peroxide dosage, high amounts of soluble chemical oxygen demand and volatile fatty acid were produced, and phosphates, nitrogen, and metals were solubilized. A high temperature and/or a higher H2O2 dosage implemented in this system yielded high solubilization of organic matters. Orthophosphate increased with an increase in treatment temperature up to 60°C, its concentration decreased as temperature further increased. There was little effect on orthophosphate release by varying H2O2 dosage. The efficiency of the RF/H2O2 process was comparable to the microwave (MW) enhanced advanced oxidation process (MW/H2O2-AOP), in terms of solids disintegration and nutrient release; however, the solubilization rate was lower for RF/H2O2 process. The overall energy consumed by the RF/H2O2 process was higher than the MW/H2O2-AOP.

  4. Process for Nitrogen Oxide Waste Conversion to Fertilizer

    NASA Technical Reports Server (NTRS)

    Lueck, Dale E. (Inventor); Parrish, Clyde F. (Inventor)

    2003-01-01

    The present invention describes a process for converting vapor streams from sources containing at least one nitrogen-containing oxidizing agent therein to a liquid fertilizer composition comprising the steps of: a) directing a vapor stream containing at least one nitrogen-containing oxidizing agent to a first contact zone; b) contacting said vapor stream with water to form nitrogen oxide(s) from said at least one nitrogen-containing oxidizing agent; c) directing said acid(s) as a second stream to a second contact zone; d) exposing said second stream to hydrogen peroxide which is present within said second contact zone in a relative amount of at least 0.1% by weight of said second stream within said second contact zone to convert at least some of any nitrogen oxide species or ions other than in the nitrate form present within said second stream to nitrate ion; e) sampling said stream within said second contact zone to determine the relative amount of hydrogen peroxide within said second contact zone; f) adding hydrogen peroxide to said second contact zone when a level of hydrogen peroxide less than 0.1 % by weight in said second stream is determined by said sampling; g) adding a solution comprising potassium hydroxide to said second stream to maintain a pH between 6.0 and 11.0 within said second stream within said second contact zone to form a solution of potassium nitrate; and h) removing said solution of potassium nitrate from said second contact zone.

  5. Lipid oxidation volatiles absent in milk after selected ultrasound processing.

    PubMed

    Juliano, Pablo; Torkamani, Amir Ehsan; Leong, Thomas; Kolb, Veronika; Watkins, Peter; Ajlouni, Said; Singh, Tanoj Kumar

    2014-11-01

    Ultrasonic processing can suit a number of potential applications in the dairy industry. However, the impact of ultrasound treatment on milk stability during storage has not been fully explored under wider ranges of frequencies, specific energies and temperature applications. The effect of ultrasonication on lipid oxidation was investigated in various types of milk. Four batches of raw milk (up to 2L) were sonicated at various frequencies (20, 400, 1000, 1600 and 2000kHz), using different temperatures (4, 20, 45 and 63°C), sonication times and ultrasound energy inputs up to 409kJ/kg. Pasteurized skim milk was also sonicated at low and high frequency for comparison. In selected experiments, non-sonicated and sonicated samples were stored at 4°C and were drawn periodically up to 14days for SPME-GCMS analysis. The cavitational yield, characterized in all systems in water, was highest between 400kHz and 1000kHz. Volatile compounds from milk lipid oxidation were detected and exceeded their odor threshold values at 400kHz and 1000kHz at specific energies greater than 271kJ/kg in raw milk. However, no oxidative volatile compounds were detected below 230kJ/kg in batch systems at the tested frequencies under refrigerated conditions. Skim milk showed a lower energy threshold for oxidative volatile formation. The same oxidative volatiles were detected after various passes of milk through a 0.3L flow cell enclosing a 20kHz horn and operating above 90kJ/kg. This study showed that lipid oxidation in milk can be controlled by decreasing the sonication time and the temperature in the system depending on the fat content in the sample among other factors.

  6. Multiphase Processing of Isoprene Oxidation Products - Kinetic and Product Studies

    NASA Astrophysics Data System (ADS)

    Hoffmann, D.; Schoene, L.; Schindelka, J.; Herrmann, H.

    2010-12-01

    Isoprene represents a significant fraction of NMHC in the troposphere with recently estimated emission rates of 500-750 TgC yr-1 (1). Due to its enormous source strength, the fate of isoprene and its degradation products is important in atmospheric processes. Possible ascendancies of such oxidation processes are the regional ozone and secondary organic aerosol (SOA) formation. Some aspects of SOA formation from isoprene and its degradation products have already been studied by chamber studies (2,3). Aqueous phase oxidation processes which may occur after phase transfer of ‘early’ oxidation products are often neglected. But these processes provide a potentially important source for organic particle mass constituents such as carboxylic acids. The majority of existing aqueous phase modelling studies focus only on ‘later’ products such as methylglyoxal and oxalic acid. Yet, a recent field study reports much higher aqueous phase concentrations of some ‘earlier’ isoprene oxidation products including methacrolein (MACR) and methyl vinyl ketone (MVK) than expected (4). This indicates a possibly underestimated importance of multiphase chemical processes in the course of the isoprene oxidation as a source for the production of organic particle mass together with known ‘heterogeneous processes’ such as the direct condensation of low-volatility products from gas phase processes onto existing particle surfaces. In order to implement the isoprene multiphase chemistry in atmospheric models detailed kinetic and mechanistic studies are needed. Hence, the temperature dependence of MACR, MVK, methacrylic acid and acrylic acid exposed to NO3, SO4- and OH radicals in the aqueous phase was investigated. The measurements were performed using a laser-photolysis laser long path absorption technique. The analysis confirmed in all cases the much higher reactivity of the OH radical in comparison to SO4- and NO3 radicals. The temperature dependence is most distinct for NO3

  7. Process for the reduction of nitrogen oxides in an effluent

    SciTech Connect

    Epperly, W.R.; Sullivan, J.C.; Sprague, B.N.

    1989-07-04

    This patent describes a process for the reduction of the concentration of nitrogen oxides in the effluent from the combustion of a carbonaceous fuel. The process comprises introducing a treatment agent which comprises a composition selected from the group consisting of NH/sub 4/-lignosulfonate, calcium lignosulfonate, 2-furoic acid, 1,3 dioxolane, tetrahydrofuran, furfurylamine, furfurylalcohol, gluconic acid, citric acid, n-butyl acetate, 1,3 butylene glycol, methylal, tetrahydrofuryl alcohol, furan, fish oil, coumalic acid, furfuryl acetate, tetrahydrofuran 2,3,4,5-tetracarboxylic acid, tetrahydrofurylamine, furylacrylic acid, tetrahydropyran, 2,5-furandimethanol, mannitol, hexamethylenediamine, barbituric acid, acetic anhydride, oxalic acid, mucic acid and d-galactose.

  8. Thermal Behavior Study of the MoVTeNb Oxide Catalyst for Selective Oxidation Process

    SciTech Connect

    Idris, R.; Hamid, S. B. Abd.

    2009-06-01

    Several parameters involved in preparing the multi metal oxide (MMO) catalysts (Mo{sub 1}V{sub 0.3}Te{sub 0.23}Nb{sub 0.12}O{sub x}) for selective oxidation of propane to acrylic acid (AA) were investigated. These included the proper pre-calcined and calcinations atmosphere effect on the performance of the catalysts. It was found that each metal element plays a critical role to the performance of an effective catalyst and also the calcinations under a non-flow inert atmosphere. The characterization results from XRD, SEM, TG and DSC show the important differences depending on the activation procedures of the MoVTeNb oxide catalyst. The XRD analysis is used to identify the phase inventory of the MoVTeNb oxide catalysts. The structure of orthorhombic M1, M2, TeMo{sub 5}O{sub 16}, V{sub 0.95}Mo{sub 0.97}O{sub 5} and Mo{sub 5}O{sub 14} phase was investigated. The orthorhombic M1 phase is the most active and selective phase and is responsible for the major of the efficiently of the best catalyst for selective oxidation process. TGA and DTG allow the identification of the number and types, of reactions involving evaporation of small molecules from removal of ligands and water to condensation or drying processes. From all these analyses it was proven that the activation procedures would affect the performance of the MoVTeNb oxide catalyst.

  9. Advanced oxidation of iodinated X-ray contrast media in reverse osmosis brines: the influence of quenching.

    PubMed

    Azerrad, Sara P; Gur-Reznik, Shirra; Heller-Grossman, Lilly; Dosoretz, Carlos G

    2014-10-01

    Among the main restrictions for the implementation of advanced oxidation processes (AOPs) for removal of micropollutants present in reverse osmosis (RO) brines of secondary effluents account the quenching performed by background organic and inorganic constituents. Natural organic matter (NOM) and soluble microbial products (SMP) are the main effluent organic matter constituents. The inorganic fraction is largely constituted by chlorides and bicarbonate alkalinity with sodium and calcium as main counterions. The quenching influence of these components, separately and their mixture, in the transformation of model compounds by UVA/TiO2 was studied applying synthetic brines solutions mimicking 2-fold concentrated RO secondary effluents brines. The results were validated using fresh RO brines. Diatrizoate (DTZ) and iopromide (IOPr) were used as model compound. They have been found to exhibit relative high resistance to oxidation process and therefore represent good markers for AOPs techniques. Under the conditions applied, oxidization of DTZ in the background of RO brines was strongly affected by quenching effects. The major contribution to quenching resulted from organic matter (≈70%) followed by bicarbonate alkalinity (≈30%). NOM displayed higher quenching than SMP in spite of its relative lower concentration. Multivalent cations, i.e., Ca(+2), were found to decrease effectiveness of the technique due to agglomeration of the catalyst. However this influence was lowered in presence of NOM. Different patterns of transformation were found for each model compound in which a delayed deiodination was observed for iopromide whereas diatrizoate oxidation paralleled deiodination.

  10. Oxidation-reduction catalyst and its process of use

    NASA Technical Reports Server (NTRS)

    Jordan, Jeffrey D. (Inventor); Watkins, Anthony Neal (Inventor); Schryer, Jacqueline L. (Inventor); Oglesby, Donald M. (Inventor)

    2008-01-01

    This invention relates generally to a ruthenium stabilized oxidation-reduction catalyst useful for oxidizing carbon monoxide, and volatile organic compounds, and reducing nitrogen oxide species in oxidizing environments, substantially without the formation of toxic and volatile ruthenium oxide species upon said oxidizing environment being at high temperatures.

  11. Adapting biomarker technologies to adverse outcome pathways (AOPs) research: current thoughts on using in vivo discovery for developing in vitro target methods

    EPA Science Inventory

    Adverse outcome pathways (AOP) research is a relatively new concept in human systems biology for assessing the molecular level linkage from an initiating (chemical) event that could lead to a disease state. Although most implementations of AOPs are based on liquids analyses, the...

  12. The first commercial supercritical water oxidation sludge processing plant.

    PubMed

    Griffith, James W; Raymond, Dennis H

    2002-01-01

    Final disposal of sludge continues to be one of the more pressing problems for the wastewater treatment industry. Present regulations for municipal sludge have favored beneficial use, primarily in land application. However, several agencies and entities have warned of potential health risks associated with these methods. Hydrothermal oxidation provides an alternative method that addresses the health concerns associated with sludge disposal by completely converting all organic matter in the sludge to carbon dioxide, water, and other innocuous materials. A hydrothermal oxidation system using HydroProcessing, L.L.C.'s HydroSolids process has been installed at Harlingen, Texas to process up to 9.8 dry tons per day of sludge. Based on a literature review, this system is the largest hydrothermal oxidation system in the world, and the only one built specifically to process a sludge. Start up of Unit 1 of two units of the HTO system began in April 2001. Early results have indicated COD conversion rates in excess of 99.9%. Harlingen Waterworks System estimates that the HydroSolids system will cost less than other alternatives such as autothermal thermophilic aerobic digestion and more traditional forms of digestion that still require dewatering and final disposal. The Waterworks intends to generate income from the sale of energy in the form of hot water and the use of carbon dioxide from the HydroSolids process for neutralization of high pH industrial effluent. The Waterworks also expects to generate income from the treatment of septage and grease trap wastes.

  13. From pathways to people: applying the adverse outcome pathway (AOP) for skin sensitization to risk assessment.

    PubMed

    MacKay, Cameron; Davies, Michael; Summerfield, Vicki; Maxwell, Gavin

    2013-01-01

    Consumer safety risk assessment of skin sensitization requires information on both consumer exposure to the ingredient through product use and the hazardous properties of the ingredient. Significant progress has been made in determining the hazard potential of ingredients without animal testing. However, hazard identification is insufficient for risk assessment, and an understanding of the dose-response is needed. Obtaining such knowledge without animal testing is challenging and requires applying available mechanistic knowledge to both assay development and the integration of these data. The recent OECD report "The Adverse Outcome Pathway for Skin Sensitization Initiated by Covalent Binding to Proteins" presents the available mechanistic knowledge of the sensitization response within an adverse outcome pathway (AOP). We propose to use this AOP as the mechanistic basis for physiologically- and mechanistically-based toxicokinetic-toxicodynamic models of the sensitization response. The approach would be informed by non-animal data, provide predictions of the dose-response required for risk assessment, and would be evaluated against human clinical data.

  14. Taxonomic applicability of inflammatory cytokines in adverse outcome pathway (AOP) development.

    PubMed

    Angrish, Michelle M; Pleil, Joachim D; Stiegel, Matthew A; Madden, Michael C; Moser, Virginia C; Herr, David W

    2016-01-01

    Cytokines, low-molecular-weight messenger proteins that act as intercellular immunomodulatory signals, have become a mainstream preclinical marker for assessing the systemic inflammatory response to external stressors. The challenge is to quantitate from healthy subjects cytokine levels that are below or at baseline and relate those dynamic and complex cytokine signatures of exposures with the inflammatory and repair pathways. Thus, highly sensitive, specific, and precise analytical and statistical methods are critically important. Investigators at the U.S. Environmental Protection Agency (EPA) have implemented advanced technologies and developed statistics for evaluating panels of inflammatory cytokines in human blood, exhaled breath condensate, urine samples, and murine biological media. Advanced multiplex, bead-based, and automated analytical platforms provided sufficient sensitivity, precision, and accuracy over the traditional enzyme-linked immunosorbent assay (ELISA). Thus, baseline cytokine levels can be quantified from healthy human subjects and animals and compared to an in vivo exposure response from an environmental chemical. Specifically, patterns of cytokine responses in humans exposed to environmental levels of ozone and diesel exhaust, and in rodents exposed to selected pesticides (such as fipronil and carbaryl), were used as case studies to generally assess the taxonomic applicability of cytokine responses. The findings in this study may aid in the application of measureable cytokine markers in future adverse outcome pathway (AOP)-based toxicity testing. Data from human and animal studies were coalesced and the possibility of using cytokines as key events (KE) to bridge species responses to external stressors in an AOP-based framework was explored.

  15. Advances in Measuring the Apparent Optical Properties (AOPs) of Optically Complex Waters

    NASA Technical Reports Server (NTRS)

    Morrow, John H.; Hooker, Stanford B.; Booth, Charles R.; Bernhard, Germar; Lind, Randall N.; Brown, James W.

    2010-01-01

    This report documents new technology used to measure the apparent optical properties (AOPs) of optically complex waters. The principal objective is to be prepared for the launch of next-generation ocean color satellites with the most capable commercial off-the-shelf (COTS) instrumentation. An enhanced COTS radiometer was the starting point for designing and testing the new sensors. The follow-on steps were to apply the lessons learned towards a new in-water profiler based on a kite-shaped backplane for mounting the light sensors. The next level of sophistication involved evaluating new radiometers emerging from a development activity based on so-called microradiometers. The exploitation of microradiometers resulted in an in-water profiling system, which includes a sensor networking capability to control ancillary sensors like a shadowband or global positioning system (GPS) device. A principal advantage of microradiometers is their flexibility in producing, interconnecting, and maintaining instruments. The full problem set for collecting sea-truth data--whether in coastal waters or the open ocean-- involves other aspects of data collection that were improved for instruments measuring both AOPs and inherent optical properties (IOPs), if the uncertainty budget is to be minimized. New capabilities associated with deploying solar references were developed as well as a compact solution for recovering in-water instrument systems from small boats.

  16. Processing, Microstructure, and Oxidation Behavior of Iron Foams

    NASA Astrophysics Data System (ADS)

    Park, Hyeji; Noh, Yoonsook; Choi, Hyelim; Hong, Kicheol; Kwon, Kyungjung; Choe, Heeman

    2016-09-01

    With its historically long popularity in major structural applications, the use of iron (Fe) has also recently begun to be explored as an advanced functional material. For this purpose, it is more advantageous to use Fe as a porous structure, simply because it can provide a greater surface area and a higher reaction rate. This study uses a freeze-casting method, which consists of simple and low-cost processing steps, to produce Fe foam with a mean pore size of 10 μm. We examine the influences of various parameters ( i.e., mold bottom temperature, powder content, and sintering time) on the processing of Fe foam, along with its oxidation kinetics at 823 K (550 °C) with various heat-treatment times. We confirm that Fe2O3 and Fe3O4 oxide layers are successfully formed on the surface of Fe foam. With the Fe oxide layers as an active anode material, the Fe foam can potentially be used as a three-dimensional anode current collector for an advanced lithium-ion battery.

  17. PROCESS FOR PRODUCTION OF PLUTONIUM FROM ITS OXIDES

    DOEpatents

    Weissman, S.I.; Perlman, M.L.; Lipkin, D.

    1959-10-13

    A method is described for obtaining a carbide of plutonium and two methods for obtaining plutonium metal from its oxides. One of the latter involves heating the oxide, in particular PuO/sub 2/, to a temperature of 1200 to 1500 deg C with the stoichiometrical amount of carbon to fornn CO in a hard vacuum (3 to 10 microns Hg), the reduced and vaporized plutonium being collected on a condensing surface above the reaction crucible. When an excess of carbon is used with the PuO/sub 2/, a carbide of plutonium is formed at a crucible temperature of 1400 to 1500 deg C. The process may be halted and the carbide removed, or the reaction temperature can be increased to 1900 to 2100 deg C at the same low pressure to dissociate the carbide, in which case the plutonium is distilled out and collected on the same condensing surface.

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

    PubMed

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

    2006-01-01

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

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

    SciTech Connect

    McClure, Zachary D.; Padilla Cintron, Cristina

    2016-09-27

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

  20. Nitrogen and carbon oxides chemistry in the HRS retorting process

    SciTech Connect

    Reynolds, J.G.

    1993-11-12

    The HRS Oil Shale Retort process consists of a pyrolysis section which converts kerogen of the shale to liquid and gaseous products, and a combustion section which burns residual carbon on the shale to heat the process. Average gas concentrations of selected gas phase species were determined from data measured at several placed on the combustion system of the Lawrence Livermore National Laboratory Hot-Recycled-Solids Retort Pilot Plant for representative rich and lean shale runs. The data was measured on-line and in real time by on-line meters (CO{sub 2}, CO, O{sub 2}), mass spectrometry (CO{sub 2}, O{sub 2}, H{sub 2}O, NO, CH{sub 4}, SO{sub 2}, N{sub 2} and Ar), and Fourier transform infrared spectroscopy (CO{sub 2}, CO, H{sub 2}O, NO, N{sub 2}O, NO{sub 2}, CH{sub 4}, SO{sub 2}, NH{sub 3}, and HCN). For both the rich and leans shale runs, the Lift-Pipe Combustor (LFT) exhibited gas concentrations (sampled at the exit of the LFT) indicative of incomplete combustion and oxidation; the Delayed-Fall Combustor (DFC) exhibited gas concentrations (sampled at the annulus and the exit of the DFC) indicative of much more complete combustion and oxidation. The Fluidized-Bed Combustor exhibited gas concentrations which were controlled to a large extent by the injection atmosphere of the FBC. High levels of nitrogen oxides and low levels of CO were detected when full air injection was used, while high levels of CO and low levels of nitrogen-oxides were detected with partial N{sub 2} injection. Sequential sampling limitations and nitrogen balances are also discussed.

  1. Microstructure Sensitive Design and Processing in Solid Oxide Electrolyzer Cell

    SciTech Connect

    Dr. Hamid Garmestani; Dr. Stephen Herring

    2009-06-12

    The aim of this study was to develop and inexpensive manufacturing process for deposition of functionally graded thin films of LSM oxides with porosity graded microstructures for use as IT-SOFCs cathode. The spray pyrolysis method was chosen as a low-temperature processing technique for deposition of porous LSM films onto dense YXZ substrates. The effort was directed toward the optimization of the processing conditions for deposition of high quality LSM films with variety of morphologies in the range of dense to porous microstructures. Results of optimization studies of spray parameters revealed that the substrate surface temperature is the most critical parameter influencing the roughness and morphology, porosity, cracking and crystallinity of the film.

  2. Processing of Non-PFP Plutonium Oxide in Hanford Plants

    SciTech Connect

    Jones, Susan A.; Delegard, Calvin H.

    2011-03-10

    Processing of non-irradiated plutonium oxide, PuO2, scrap for recovery of plutonium values occurred routinely at Hanford’s Plutonium Finishing Plant (PFP) in glovebox line operations. Plutonium oxide is difficult to dissolve, particularly if it has been high-fired; i.e., calcined to temperatures above about 400°C and much of it was. Dissolution of the PuO2 in the scrap typically was performed in PFP’s Miscellaneous Treatment line using nitric acid (HNO3) containing some source of fluoride ion, F-, such as hydrofluoric acid (HF), sodium fluoride (NaF), or calcium fluoride (CaF2). The HNO3 concentration generally was 6 M or higher whereas the fluoride concentration was ~0.5 M or lower. At higher fluoride concentrations, plutonium fluoride (PuF4) would precipitate, thus limiting the plutonium dissolution. Some plutonium-bearing scrap also contained PuF4 and thus required no added fluoride. Once the plutonium scrap was dissolved, the excess fluoride was complexed with aluminum ion, Al3+, added as aluminum nitrate, Al(NO3)3•9H2O, to limit collateral damage to the process equipment by the corrosive fluoride. Aluminum nitrate also was added in low quantities in processing PuF4.

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

    PubMed

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

    2010-01-01

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

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

    PubMed

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

    2013-01-02

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

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

    PubMed Central

    2013-01-01

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

  6. Processing and Oxidation Behavior of Nb-Si-B Intermetallics

    SciTech Connect

    Y.LIU; A.J. Thom; M.J. Kramer; M. Akinc

    2004-09-30

    Single phase materials of {alpha}-Nb{sub 5}Si{sub 3}, Nb{sub 5}(Si,B){sub 3} (T2) and Nb{sub 5}Si{sub 3}B{sub x} (D8{sub 8}) in the Nb-Si-B system were prepared by powder metallurgy processing. T2 was almost fully dense, while {alpha}-Nb{sub 5}Si{sub 3} and D8{sub 8} were porous after sintering at 1900 C for 2 hours. The lattice parameters of T2 decreased linearly with the substitution of B for Si. Isothermal oxidation testing at 1000 C in flowing air indicated that the oxidation resistances of T2 and D8{sub 8} are much better than {alpha}-Nb{sub 5}Si{sub 3}, but still extremely poor compared to the boron-modified Mo{sub 5}Si{sub 3}. Extensive cracking in the oxide scale and matrix were observed and arose from the volume expansion associated with the formation of Nb{sub 2}O{sub 5} and boron-containing silica glass.

  7. Process for depositing epitaxial alkaline earth oxide onto a substrate and structures prepared with the process

    DOEpatents

    McKee, Rodney A.; Walker, Frederick J.

    1996-01-01

    A process and structure involving a silicon substrate utilize molecular beam epitaxy (MBE) and/or electron beam evaporation methods and an ultra-high vacuum facility to grow a layup of epitaxial alkaline earth oxide films upon the substrate surface. By selecting metal constituents for the oxides and in the appropriate proportions so that the lattice parameter of each oxide grown closely approximates that of the substrate or base layer upon which oxide is grown, lattice strain at the film/film or film/substrate interface of adjacent films is appreciably reduced or relieved. Moreover, by selecting constituents for the oxides so that the lattice parameters of the materials of adjacent oxide films either increase or decrease in size from one parameter to another parameter, a graded layup of films can be grown (with reduced strain levels therebetween) so that the outer film has a lattice parameter which closely approximates that of, and thus accomodates the epitaxial growth of, a pervoskite chosen to be grown upon the outer film.

  8. Adverse Outcome Pathway (AOP) Informed Modeling of Aquatic Toxicology: QSARs, Read-Across, and Interspecies Verification of Modes of Action.

    PubMed

    Ellison, Claire M; Piechota, Przemyslaw; Madden, Judith C; Enoch, Steven J; Cronin, Mark T D

    2016-04-05

    Alternative approaches have been promoted to reduce the number of vertebrate and invertebrate animals required for the assessment of the potential of compounds to cause harm to the aquatic environment. A key philosophy in the development of alternatives is a greater understanding of the relevant adverse outcome pathway (AOP). One alternative method is the fish embryo toxicity (FET) assay. Although the trends in potency have been shown to be equivalent in embryo and adult assays, a detailed mechanistic analysis of the toxicity data has yet to be performed; such analysis is vital for a full understanding of the AOP. The research presented herein used an updated implementation of the Verhaar scheme to categorize compounds into AOP-informed categories. These were then used in mechanistic (quantitative) structure-activity relationship ((Q)SAR) analysis to show that the descriptors governing the distinct mechanisms of acute fish toxicity are capable of modeling data from the FET assay. The results show that compounds do appear to exhibit the same mechanisms of toxicity across life stages. Thus, this mechanistic analysis supports the argument that the FET assay is a suitable alternative testing strategy for the specified mechanisms and that understanding the AOPs is useful for toxicity prediction across test systems.

  9. Quantitative AOP-based predictions for two aromatase inhibitors evaluating the influence of bioaccumulation on prediction accuracy

    EPA Science Inventory

    The adverse outcome pathway (AOP) framework can be used to support the use of mechanistic toxicology data as a basis for risk assessment. For certain risk contexts this includes defining, quantitative linkages between the molecular initiating event (MIE) and subsequent key events...

  10. Adverse Outcome Pathway (AOP) for a Mutagenic Mode of Action for Cancer: AFB1 and Hepatocellular Carcinoma (HCC)

    EPA Science Inventory

    AOPs provide a framework to describe a sequence of measureable key events (KEs), beginning with a molecular initiating event (MIE), followed by a series of identified KEs linked to one another by KE Relationships (KERs), all anchored by a specific adverse outcome (AO). Each KE/KE...

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

    PubMed

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

    2015-05-15

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

  12. Improved thermal oxidation stability of solution-processable silver nanowire transparent electrode by reduced graphene oxide.

    PubMed

    Ahn, Yumi; Jeong, Youngjun; Lee, Youngu

    2012-12-01

    Solution-processable silver nanowire-reduced graphene oxide (AgNW-rGO) hybrid transparent electrode was prepared in order to replace conventional ITO transparent electrode. AgNW-rGO hybrid transparent electrode exhibited high optical transmittance and low sheet resistance, which is comparable to ITO transparent electrode. In addition, it was found that AgNW-rGO hybrid transparent electrode exhibited highly enhanced thermal oxidation and chemical stabilities due to excellent gas-barrier property of rGO passivation layer onto AgNW film. Furthermore, the organic solar cells with AgNW-rGO hybrid transparent electrode showed good photovoltaic behavior as much as solar cells with AgNW transparent electrode. It is expected that AgNW-rGO hybrid transparent electrode can be used as a key component in various optoelectronic application such as display panels, touch screen panels, and solar cells.

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

    PubMed

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

    2008-05-01

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

  14. Process for depositing an oxide epitaxially onto a silicon substrate and structures prepared with the process

    DOEpatents

    McKee, Rodney A.; Walker, Frederick J.

    1993-01-01

    A process and structure involving a silicon substrate utilizes an ultra high vacuum and molecular beam epitaxy (MBE) methods to grow an epitaxial oxide film upon a surface of the substrate. As the film is grown, the lattice of the compound formed at the silicon interface becomes stabilized, and a base layer comprised of an oxide having a sodium chloride-type lattice structure grows epitaxially upon the compound so as to cover the substrate surface. A perovskite may then be grown epitaxially upon the base layer to render a product which incorporates silicon, with its electronic capabilities, with a perovskite having technologically-significant properties of its own.

  15. Improvement in AOD retrieval from geostationary measurement over the ASIA with obtained AOP from DRAGON-2012 campaign

    NASA Astrophysics Data System (ADS)

    Choi, M.; KIM, M.; Kim, J.; Lee, J.

    2013-12-01

    The long-term aerosol monitoring from ground-based sun photometer such as AERONET has variously used to obtain optimized aerosol optical properties (AOPs) for assumed aerosol type and to validate aerosol optical depth (AOD) retrieved from satellite. Additionally, the meso-scale network campaign such as DRAGON ASIA-2012 is suitable to monitor the aerosol characteristic over localized area. Thus, this study focused on the improvement of AOPs over the East Asia by using the DRAGON ASIA-2012 campaign dataset for two geostationary AOD retrieval algorithms. The algorithms were developed for Geostationary Ocean Color Imager (GOCI) and Meteorological Imager (MI) onboarding the Communication, Ocean, and Meteorological Satellite (COMS), which was launched in June, 2010. GOCI has 8 channels in visible and near IR. Using these multi-spectral bands, we retrieved aerosol optical properties such as AOD, fine-mode fraction (FMF), single scattering albedo (SSA) and aerosol type. In this study, we consider dynamic aerosol models categorized by FMF and SSA from East Asia AERONET data including DRAGON campaign data. Using these aerosol data, AOPs are upgraded for LUT calculation and re-retrieved from GOCI. The validation with AERONET shows the improved results after AOP upgrade. On the other hand, a single channel algorithm developed for MI assumed seasonal aerosol property variation due the algorithm has limitation in select aerosol type. The seasonally analyzed SSAs at 675 nm from the AERONET measurement over the East Asia including the campaign data are 0.92, 0.94, 0.92, and 0.91 for spring (MAM), summer (JJA), autumn (SON), and winter (DJF), respectively, and slightly higher then the originally used values. By using those newly analyzed AOP, the comparison result between retrieved AOD and measured value from AERONET shows the increase of correlation coefficient from 0.551 to 0.702 and the increase of regression slope from 0.538 to 0.615 during months from May to Dec. in 2011.

  16. Study on emission characteristics and reduction strategy of nitrous oxide during wastewater treatment by different processes.

    PubMed

    Sun, Shichang; Bao, Zhiyuan; Sun, Dezhi

    2015-03-01

    Given the inexorable increase in global wastewater treatment, increasing amounts of nitrous oxide are expected to be emitted from wastewater treatment plants and released to the atmosphere. It has become imperative to study the emission and control of nitrous oxide in the various wastewater treatment processes currently in use. In the present investigation, the emission characteristics and the factors affecting the release of nitrous oxide were studied via full- and pilot-scale experiments in anoxic-oxic, sequencing batch reactor and oxidation ditch processes. We propose an optimal treatment process and relative strategy for nitrous oxide reduction. Our results show that both the bio-nitrifying and bio-denitrifying treatment units in wastewater treatment plants are the predominant sites for nitrous oxide production in each process, while the aerated treatment units are the critical sources for nitrous oxide emission. Compared with the emission of nitrous oxide from the anoxic-oxic (1.37% of N-influent) and sequencing batch reactor (2.69% of N-influent) processes, much less nitrous oxide (0.25% of N-influent) is emitted from the oxidation ditch process, which we determined as the optimal wastewater treatment process for nitrous oxide reduction, given the current technologies. Nitrous oxide emissions differed with various operating parameters. Controlling the dissolved oxygen concentration at a proper level during nitrification and denitrification and enhancing the utilization rate of organic carbon in the influent for denitrification are the two critical methods for nitrous oxide reduction in the various processes considered.

  17. Simultaneous constraint and phase conversion processing of oxide superconductors

    DOEpatents

    Li, Qi; Thompson, Elliott D.; Riley, Jr., Gilbert N.; Hellstrom, Eric E.; Larbalestier, David C.; DeMoranville, Kenneth L.; Parrell, Jeffrey A.; Reeves, Jodi L.

    2003-04-29

    A method of making an oxide superconductor article includes subjecting an oxide superconductor precursor to a texturing operation to orient grains of the oxide superconductor precursor to obtain a highly textured precursor; and converting the textured oxide superconducting precursor into an oxide superconductor, while simultaneously applying a force to the precursor which at least matches the expansion force experienced by the precursor during phase conversion to the oxide superconductor. The density and the degree of texture of the oxide superconductor precursor are retained during phase conversion. The constraining force may be applied isostatically.

  18. Carbon oxides free fuel processing for fuel cell applications

    NASA Astrophysics Data System (ADS)

    Choudhary, Tushar V.

    Fuel processing represents a very important aspect of fuel cell technology. The widespread utilization of fuel cells will only be possible if CO x-free hydrogen producing technologies are developed. Towards this objective, step-wise reforming of hydrocarbons and catalytic decomposition of ammonia were investigated for hydrogen production. Also, novel Au-based catalysts were synthesized for preferentially eliminating CO in the presence of excess hydrogen. The step-wise reforming of hydrocarbons was investigated for production of CO-free hydrogen for proton exchange membrane fuel cells. Proof of concept pulse reactor experiments employing Ni-based catalysts clearly showed the feasibility of the cyclic step-wise reforming process for clean hydrogen production. Under optimum conditions the CO content in the hydrogen was found to be less than 20 ppm by this process (a large amount of CO is obtained as a by-product from conventional methods of hydrogen production). The step-wise reforming process thus greatly simplifies fuel reforming, as expensive and circuitous post-reforming hydrogen purification processes are eliminated. The process was profoundly influenced by the operating temperature, space velocity and nature of the catalyst support. Catalytic ammonia decomposition was investigated for COx-free hydrogen production for alkaline fuel cells. These studies revealed that Ru, Ir and Ni-based catalysts were active for the process with Ru being the most active and Ni the least. The catalyst supports played a decisive role in determining the ammonia decomposition activity. Partial pressure dependence studies of the reaction rate on model Ir (100) catalysts yielded a positive order (0.9 +/- 0.l) with respect to ammonia and negative order (-0.7 +/- 0.l) with respect to hydrogen. The negative order with respect to hydrogen was attributed to the enhancement in the reverse of the ammonia decomposition reaction in the presence of surface hydrogen atoms. Novel nano-Au catalysts

  19. Biological assessment of bisphenol A degradation in water following direct photolysis and UV advanced oxidation.

    PubMed

    Chen, Pei-Jen; Linden, Karl G; Hinton, David E; Kashiwada, Shosaku; Rosenfeldt, Erik J; Kullman, Seth W

    2006-11-01

    Endocrine disrupting compounds (EDCs) are exogenous environmental chemicals that can interfere with normal hormone function and present a potential threat to both environmental and human health. The fate, distribution and degradation of EDCs is a subject of considerable investigation. To date, several studies have demonstrated that conventional water treatment processes are ineffective for removal of most EDCs and in some instances produce multiple unknown transformation products. In this study we have investigated the use of direct photolysis with low-pressure (LP) Hg UV lamps and UV+hydrogen peroxide (H(2)O(2)) advanced oxidation process (AOP) for the degradation of a prototypic endocrine disrupter, bisphenol A (BPA), in laboratory water. Removal rates of BPA and formation of degradation products were determined by high performance liquid chromatography (HPLC) analysis. Changes in estrogenic activity were evaluated using both in vitro yeast estrogen screen (YES) and in vivo vitellogenin (VTG) assays with Japanese medaka fish (Oryzias latipes). Our results demonstrate that UV alone did not effectively degrade BPA. However, UV in combination with H(2)O(2) significantly removed BPA parent compound and aqueous estrogenic activity in vitro and in vivo. Removal rates of in vivo estrogenic activity were significantly lower than those observed in vitro, demonstrating differential sensitivities of these bioassays and that certain UV/AOP metabolites may retain estrogenic activity. Furthermore, the UV/H(2)O(2) AOP was effective for reducing larval lethality in treated BPA solutions, suggesting BPA degradation occurred and that the degradation process did not result in the production of acutely toxic intermediates.

  20. Chemical composition and direct electrochemical oxidation of table olive processing wastewater using high oxidation power anodes.

    PubMed

    Gargouri, Boutheina; Gargouri, Olfa Dridi; Khmakhem, Ibtihel; Ammar, Sonda; Abdelhèdi, Ridha; Bouaziz, Mohamed

    2017-01-01

    Table olive processing wastewater (TOW) is a notoriously polluting due to its high organic and phenol content. To reduce them, an electrochemical process has been studied for the treatment of this effluent. Experiments were performed with a cell equipped with lead dioxide (PbO2) or boron-doped diamond (BDD) as anode and platinum as cathode, where Table Olive Wastewater (TOW) were destroyed by hydroxyl radicals formed at the anode surface from water oxidation. The comparative study of both systems shows the performance of the BDD anode compared to PbO2, explained by the large amounts of hydroxyl radicals generated effective at BDD anode and its synthesis characteristics. Using LC/MS analysis, it was possible to determine hydroxytyrosol, as major phenolic compounds, in table olive processing wastewater and its concentration reach 890 mg L(-1). A possible reaction mechanism oxidation for hydroxytyrosol was proposed. The kinetics decays for hydroxytyrosol degradation on PbO2 anode follows a pseudo-first order reaction with a rate constant 0.9 h(-1) for japp value 20 mA cm(-2).

  1. Process for making surfactant capped metal oxide nanocrystals, and products produced by the process

    DOEpatents

    Alivisatos, A. Paul; Rockenberger, Joerg

    2006-01-10

    Disclosed is a process for making surfactant capped nanocrystals of metal oxides which are dispersable in organic solvents. The process comprises decomposing a metal cupferron complex of the formula MXCupX, wherein M is a metal, and Cup is a N-substituted N-Nitroso hydroxylamine, in the presence of a coordinating surfactant, the reaction being conducted at a temperature ranging from about 150 to about 400.degree. C., for a period of time sufficient to complete the reaction. Also disclosed are compounds made by the process.

  2. Measurement of the initial phase of ozone decomposition in water and wastewater by means of a continuous quench-flow system: application to disinfection and pharmaceutical oxidation.

    PubMed

    Buffle, Marc-Olivier; Schumacher, Jochen; Salhi, Elisabeth; Jekel, Martin; von Gunten, Urs

    2006-05-01

    Due to a lack of adequate experimental techniques, the kinetics of the first 20s of ozone decomposition in natural water and wastewater is still poorly understood. Introducing a continuous quench-flow system (CQFS), measurements starting 350 ms after ozone addition are presented for the first time. Very high HO. to O3 exposures ratios (Rct=integralHO.dt/integralO3dt) reveal that the first 20s of ozonation present oxidation conditions that are similar to ozone-based advanced oxidation processes (AOP). The oxidation of carbamazepine could be accurately modeled using O3 and HO. exposures measured with CQFS during wastewater ozonation. These results demonstrate the applicability of bench scale determined second-order rate constants for wastewater ozonation. Important degrees of pharmaceutical oxidation and microbial inactivation are predicted, indicating that a significant oxidation potential is available during wastewater ozonation, even when ozone is entirely decomposed in the first 20s.

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

    PubMed

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

    2016-10-15

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

  4. The effect of upper gastrointestinal system endoscopy process on serum oxidative stress levels.

    PubMed

    Turan, Mehmet Nuri; Aslan, Mehmet; Bolukbas, Filiz Fusun; Bolukbas, Cengiz; Selek, Sahbettin; Sabuncu, Tevfik

    2016-12-01

    Some authors have investigated the effects of oxidative stress in some process such as undergoing laparoscopic. However, the effect of upper gastrointestinal system endoscopy process on oxidative stress is unclear. We evaluated the short-term effect of upper gastrointestinal system endoscopy process on oxidative stress. Thirty patients who underwent endoscopy process and 20 healthy controls were enrolled in the prospective study. Serum total antioxidant capacity and total oxidant status measurements were measured before and after endoscopy process. The ratio percentage of total oxidant status to total antioxidant capacity was regarded as oxidative stress index. Before endoscopy process, serum total antioxidant capacity levels were higher, while serum total oxidant status levels and oxidative stress index values were lower in patients than controls, but this difference was not statistically significant (all, p > 0.05). After endoscopy process, serum total antioxidant capacity and total oxidant status levels were significantly higher in patients than before endoscopy process (both, p < 0.05). However, oxidative stress index values were slight higher in patients but this difference was not statistically significant (p > 0.05). We observed that serum TAC and TOS levels were increased in patients who underwent endoscopy process after endoscopy process. However, short-time upper gastrointestinal system endoscopy process did not cause an important change in the oxidative stress index. Further studies enrolling a larger number of patients are required to clarify the results obtained here.

  5. Magnesium Recycling of Partially Oxidized, Mixed Magnesium-Aluminum Scrap through Combined Refining and Solid Oxide Membrane Electrolysis Processes

    SciTech Connect

    Xiaofei Guan; Peter A. Zink; Uday B. Pal; Adam C. Powell

    2012-01-01

    Pure magnesium (Mg) is recycled from 19g of partially oxidized 50.5wt.% Mg-Aluminum (Al) alloy. During the refining process, potentiodynamic scans (PDS) were performed to determine the electrorefining potential for magnesium. The PDS show that the electrorefining potential increases over time as the magnesium content inside the Mg-Al scrap decreases. Up to 100% percent of magnesium is refined from the Mg-Al scrap by a novel refining process of dissolving magnesium and its oxide into a flux followed by vapor phase removal of dissolved magnesium and subsequently condensing the magnesium vapor. The solid oxide membrane (SOM) electrolysis process is employed in the refining system to enable additional recycling of magnesium from magnesium oxide (MgO) in the partially oxidized Mg-Al scrap. The combination of the refining and SOM processes yields 7.4g of pure magnesium.

  6. Magnesium Recycling of Partially Oxidized, Mixed Magnesium-Aluminum Scrap Through Combined Refining and Solid Oxide Membrane (SOM) Electrolysis Processes

    SciTech Connect

    Guan, Xiaofei; Zink, Peter; Pal, Uday

    2012-03-11

    Pure magnesium (Mg) is recycled from 19g of partially oxidized 50.5wt.%Mg-Aluminum (Al) alloy. During the refining process, potentiodynamic scans (PDS) were performed to determine the electrorefining potential for magnesium. The PDS show that the electrorefining potential increases over time as the Mg content inside the Mg-Al scrap decreases. Up to 100% percent of magnesium is refined from the Mg-Al scrap by a novel refining process of dissolving magnesium and its oxide into a flux followed by vapor phase removal of dissolved magnesium and subsequently condensing the magnesium vapors in a separate condenser. The solid oxide membrane (SOM) electrolysis process is employed in the refining system to enable additional recycling of magnesium from magnesium oxide (MgO) in the partially oxidized Mg-Al scrap. The combination of the refining and SOM processes yields 7.4g of pure magnesium; could not collect and weigh all of the magnesium recovered.

  7. Removal of Hazardous Pollutants from Wastewaters: Applications of TiO 2 -SiO 2 Mixed Oxide Materials

    DOE PAGES

    Rasalingam, Shivatharsiny; Peng, Rui; Koodali, Ranjit T.

    2014-01-01

    The direct release of untreated wastewaters from various industries and households results in the release of toxic pollutants to the aquatic environment. Advanced oxidation processes (AOP) have gained wide attention owing to the prospect of complete mineralization of nonbiodegradable organic substances to environmentally innocuous products by chemical oxidation. In particular, heterogeneous photocatalysis has been demonstrated to have tremendous promise in water purification and treatment of several pollutant materials that include naturally occurring toxins, pesticides, and other deleterious contaminants. In this work, we have reviewed the different removal techniques that have been employed for water purification. In particular, the applicationmore » of TiO 2 -SiO 2 binary mixed oxide materials for wastewater treatment is explained herein, and it is evident from the literature survey that these mixed oxide materials have enhanced abilities to remove a wide variety of pollutants.« less

  8. Process for removal of sulfur oxides from waste gases

    SciTech Connect

    Itoh, T.; Kawamata, N.; Takahashi, N.

    1980-03-18

    Sulfur oxides are removed from a waste gas containing SO/sub 2/ by: scrubbing the gas with an aqueous slurry containing Mg(OH)/sub 2/ as well as gypsum thereby to transform the SO/sub 2/ into MgSO/sub 3/ and to fix the same in this slurry; oxidizing the MgSO/sub 3/ in this slurry to convert the same into MgSO/sub 4/; filtering the slurry containing an aqueous solution of the MgSO4 thus formed and gypsum thereby to recover the gypsum; and adding Ca(OH)/sub 2/ to the aqueous solution of the MgSO/sub 4/ of the filtrate thereby to convert, by double decomposition reaction, at least the greater part of the MgSO/sub 4/ into Mg(OH)/sub 2/ and, at the same time, the Ca(OH)/sub 2/ into gypsum, the resulting aqueous slurry containing the Mg(OH/sub 2/ thus formed as well as the gypsum being used for the above mentioned scrubbing of the waste gas. The double decomposition reaction in this process is carried out in the presence of seed crystals of gypsum to obtain gypsum of good quality.

  9. Involvement of nitric oxide in learning & memory processes

    PubMed Central

    Paul, Vanaja; Ekambaram, Perumal

    2011-01-01

    Nitric oxide (NO), synthesized from the amino acid, L-arginine by nitric oxide synthase (NOS) has received attention as a neurotransmitter in the brain. NO has been found to induce cognitive behaviour in experimental animals. In order to show evidence for the involvement of NO in learning and memory processes, the reports indicating the effects of its precursor, donors, and inhibitors of its synthesis in mammals, birds, fishes and invertebrates have been reviewed. Further, learning and memory impairment occurring in man and animals due to defective NO activity in the brain due to pathological conditions such as epilepsy, stress, diabetes and side effects of therapeutic agents and reversal of this condition by L-arginine and NO donors have been included. In addition, the reports that indicate ageing-induced impairment of cognition that is known to occur in Alzheimer's disease due to deposition of the toxic protein, beta amyloid and the effect of L-arginine and NO donors in preventing dementia in these patients have been reviewed. PMID:21623030

  10. Single-Step Process toward Achieving Superhydrophobic Reduced Graphene Oxide.

    PubMed

    Li, Zhong; Tang, Xiu-Zhi; Zhu, Wenyu; Thompson, Brianna C; Huang, Mingyue; Yang, Jinglei; Hu, Xiao; Khor, Khiam Aik

    2016-05-04

    We report the first use of spark plasma sintering (SPS) as a single-step process to achieve superhydrophobic reduced graphene oxide (rGO). It was found that SPS was capable of converting smooth and electrically insulating graphene oxide (GO) sheets into highly electrically conductive rGO with minimum residual oxygen and hierarchical roughness which could be well retained after prolonged ultrasonication. At a temperature of 500 °C, which is lower than the conventional critical temperature for GO exfoliation, GO was successfully exfoliated, reduced, and hierarchically roughened. rGO fabricated by only 1 min of treatment at 1050 °C was superhydrophobic with a surface roughness (Ra) 10 times as large as that of GO as well as an extraordinarily high C:O ratio of 83.03 (atom %) and water contact angle of 153°. This demonstrates that SPS is a superior GO reduction technique, which enabled superhydrophobic rGO to be quickly and effectively achieved in one single step. Moreover, the superhydrophobic rGO fabricated by SPS showed an impressive bacterial antifouling and inactivation effect against Escherichia coli in both aqueous solution and the solid state. It is envisioned that the superhydrophobic rGO obtained in this study can be potentially used for a wide range of industrial and biomedical applications, such as the fabrication of self-cleaning and antibacterial surfaces.

  11. Fluidized-bed copper oxide process. Proof-of-concept unit design

    SciTech Connect

    Shah, P.P.; Takahashi, G.S.; Leshock, D.G.

    1991-10-14

    The fluidized-bed copper oxide process was developed to simultaneously remove sulfur dioxide and nitrogen oxide contaminants from the flue gas of coal-fired utility boilers. This dry and regenerable process uses a copper oxide sorbent in a fluidized-bed reactor. Contaminants are removed without generating waste material. (VC)

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

    PubMed

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

    2016-01-01

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

  13. Pro-oxidant and antioxidant processes in aquatic invertebrates.

    PubMed

    Canesi, Laura

    2015-03-01

    Most aquatic organisms behave as conformers with respect to environmental variables, including changes in O2 availability. Aquatic species that show tolerance to hypoxia/anoxia or hyperoxia can be excellent models for investigating physiological and biochemical adaptations that deal with changing O2 and consequent changes in metabolic rate and production of reactive oxygen species (ROS). Here, I summarize selected data on ROS production and antioxidant defenses in a model marine invertebrate, the bivalve Mytilus, under different environmental and physiological conditions. An example of other bivalves adapted to particular environments (the Antarctic Sea) is also reported. These studies contributed to the knowledge on pro-oxidant and antioxidant processes in aquatic invertebrates from comparative and environmental perspectives. A common role for metallothioneins in antioxidant protection in mammals and aquatic invertebrates is underlined in different conditions, from human disease to responses to environmental exposure to heavy metals.

  14. Cobalt-based nanocatalysts for green oxidation and hydrogenation processes.

    PubMed

    Jagadeesh, Rajenahally V; Stemmler, Tobias; Surkus, Annette-Enrica; Bauer, Matthias; Pohl, Marga-Martina; Radnik, Jörg; Junge, Kathrin; Junge, Henrik; Brückner, Angelika; Beller, Matthias

    2015-06-01

    This protocol describes the preparation of cobalt-based nanocatalysts and their applications in environmentally benign redox processes for fine chemical synthesis. The catalytically active material consists of nanoscale Co3O4 particles surrounded by nitrogen-doped graphene layers (NGrs), which have been prepared by pyrolysis of phenanthroline-ligated cobalt acetate on carbon. The resulting materials have been found to be excellent catalysts for the activation of both molecular oxygen and hydrogen; in all tested reactions, water was the only by-product. By applying these catalysts, green oxidations of alcohols and hydrogenation of nitroarenes for the synthesis of nitriles, esters and amines are demonstrated. The overall time required for catalyst preparation and for redox reactions is 35 h and 10-30 h, respectively.

  15. Uniting Gradual and Abrupt set Processes in Resistive Switching Oxides

    NASA Astrophysics Data System (ADS)

    Fleck, Karsten; La Torre, Camilla; Aslam, Nabeel; Hoffmann-Eifert, Susanne; Böttger, Ulrich; Menzel, Stephan

    2016-12-01

    Identifying limiting factors is crucial for a better understanding of the dynamics of the resistive switching phenomenon in transition-metal oxides. This improved understanding is important for the design of fast-switching, energy-efficient, and long-term stable redox-based resistive random-access memory devices. Therefore, this work presents a detailed study of the set kinetics of valence change resistive switches on a time scale from 10 ns to 104 s , taking Pt /SrTiO3/TiN nanocrossbars as a model material. The analysis of the transient currents reveals that the switching process can be subdivided into a linear-degradation process that is followed by a thermal runaway. The comparison with a dynamical electrothermal model of the memory cell allows the deduction of the physical origin of the degradation. The origin is an electric-field-induced increase of the oxygen-vacancy concentration near the Schottky barrier of the Pt /SrTiO3 interface that is accompanied by a steadily rising local temperature due to Joule heating. The positive feedback of the temperature increase on the oxygen-vacancy mobility, and thereby on the conductivity of the filament, leads to a self-acceleration of the set process.

  16. Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor

    NASA Technical Reports Server (NTRS)

    Barnard, Thomas Duncan (Inventor); Lipowitz, Jonathan (Inventor); Nguyen, Kimmai Thi (Inventor)

    2001-01-01

    A process for producing polycrystalline silicon carbide by heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent.

  17. Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor

    NASA Technical Reports Server (NTRS)

    Barnard, Thomas Duncan (Inventor); Lipowitz, Jonathan (Inventor); Nguyen, Kimmai Thi (Inventor)

    2000-01-01

    A process for producing polycrystalline silicon carbide includes heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent.

  18. Fabrication and characterization of oxide-based thin film transistors, and process development for oxide heterostructures

    NASA Astrophysics Data System (ADS)

    Lim, Wantae

    2009-12-01

    This dissertation is focused on the development of thin film transistors (TFTs) using oxide materials composed of post-transitional cations with (n-1)d 10ns0 (n≥4). The goal is to achieve high performance oxide-based TFTs fabricated at low processing temperature on either glass or flexible substrates for next generation display applications. In addition, etching mechanism and Ohmic contact formation for oxide heterostructure (ZnO/CuCrO 2) system is demonstrated. The deposition and characterization of oxide semiconductors (In 2O3-ZnO, and InGaZnO4) using a RF-magnetron sputtering system are studied. The main influence on the resistivity of the films is found to be the oxygen partial pressure in the sputtering ambient. The films remained amorphous and transparent (> 70%) at all process conditions. These films showed good transmittance at suitable conductivity for transistor fabrication. The electrical characteristics of both top- and bottom-gate type Indium Zinc Oxide (InZnO) and Indium Gallium Zinc Oxide (InGaZnO4)-based TFTs are reported. The InZnO films were favorable for depletion-mode TFTs due to their tendency to form oxygen vacancies, while enhancement-mode devices were realized with InGaZnO4 films. The InGaZnO4-based TFTs fabricated on either glass or plastic substrates at low temperature (<100°C) exhibit good electrical properties: the saturation mobility of 5--12 cm2.V-1.s-1 and threshold voltage of 0.5--2.5V. The devices are also examined as a function of aging time in order to verify long-term stability in air. The effect of gate dielectric materials on electrical properties of InGaZnO 4-based TFTs was investigated. The use of SiNx film as a gate dielectric reduces the trap density and the roughness at the channel/gate dielectric interface compared to SiO2 gate dielectric, resulting in an improvement of device parameters by reducing scattering of trapped charges at the interface. The quality of interface is shown to have large effect on TFT performance

  19. Computational consideration on advanced oxidation degradation of phenolic preservative, methylparaben, in water: mechanisms, kinetics, and toxicity assessments.

    PubMed

    Gao, Yanpeng; An, Taicheng; Fang, Hansun; Ji, Yuemeng; Li, Guiying

    2014-08-15

    Hydroxyl radicals ((•)OH) are strong oxidants that can degrade organic pollutants in advanced oxidation processes (AOPs). The mechanisms, kinetics, and toxicity assessment of the (•)OH-initiated oxidative degradation of the phenolic preservative, methylparaben (MPB), were systematically investigated using a computational approach, as the supplementary information for experimental data. Results showed that MPB can be initially attacked by (•)OH via OH-addition and H-abstraction routes. Among these routes, the (•)OH addition to the C atom at the ortho-position of phenolic hydroxyl group was the most significant route. However, the methyl-H-abstraction route also cannot be neglected. Further, the formed transient intermediates, OH-adduct ((•)MPB-OH1) and dehydrogenated radical ((•)MPB(-H)α), could be easily transformed to several stable degradation products in the presence of O2 and (•)OH. To better understand the potential toxicity of MPB and its products to aquatic organisms, both acute and chronic toxicities were assessed computationally at three trophic levels. Both MPB and its products, particularly the OH-addition products, are harmful to aquatic organisms. Therefore, the application of AOPs to remove MPB should be carefully performed for safe water treatment.

  20. Performance of electrochemical oxidation and photocatalysis in terms of kinetics and energy consumption. New insights into the p-cresol degradation.

    PubMed

    Escudero, Carlos J; Iglesias, Olalla; Dominguez, Sara; Rivero, Maria J; Ortiz, Inmaculada

    2016-05-03

    This work reports the comparative performance of two Advanced Oxidation Processes (AOPs), electrochemical oxidation and photocatalysis, as individual technological alternatives for the treatment of effluents containing p-cresol. First, the influence of operating parameters in the oxidation and mineralization yield was carried out together with kinetic analysis. Boron Doped Diamond (BDD), RuO2 and Pt as anodic materials, Na2SO4 and NaCl as supporting electrolytes and different current densities were evaluated in electrochemical oxidation whereas the effect of TiO2 concentration and radiation was studied in the photocatalytic degradation. Then, the parameter Electrical Energy per Order (EEO) was calculated to compare the energy consumption in both AOPs, concluding that under the studied conditions the electrochemical treatment with BDD, Na2SO4 and 125 A m(-2) showed the best energy efficiency, with an EEO of 5.83 kW h m(-3) order(-1) for p-cresol and 58.05 kW h m(-3) order(-1) for DOC removal, respectively.

  1. Test of TDA's Direct Oxidation Process for Sulfur Recovery

    SciTech Connect

    Girish Srinivas; Steven C. Gebhard; Eugene Peeples; Sandra Huzyk; Randy Welch

    2005-01-01

    This project was a Phase III pilot plant test of TDA's gas sweetening process done under realistic conditions. TDA Research Inc successfully completed the test at Whiting Petroleum's Sable San Andreas Gas Plant. The feed was approximately 228,000 standard cubic feet per day (SCFD) of gas that contained approximately 60 vol% CO{sub 2}, 20 vol% CH{sub 4} and 10 vol% C{sub 3}+ and higher hydrocarbons. The feed was associated gas from CO{sub 2} flooding operations carried out on Whiting's oil wells. The gas is collected and piped to the Sable gas plant where it is normally flared. We sited our pilot plant in line with the flare so that we could remove the hydrogen sulfide (H{sub 2}S) prior to flaring. The average H{sub 2}S concentration in the gas during the field test was 7341 ppm. The selectivity of our process for converting H{sub 2}S into elemental sulfur was essentially 100% and the catalyst converted 90% of the H{sub 2}S into sulfur and water (the remaining 10% of the H{sub 2}S passed through unconverted). Importantly, no catalyst deactivation was observed for over the course of the 1000+ hour test. Minimal (ca. 10-15 ppm) of SO{sub 2} was formed during the test. Approximately 3.6 tons of elemental sulfur was recovered from a total inlet of 3.9 tons of sulfur (as H{sub 2}S). The total amount of SO{sub 2} released from the plant (taking into account flaring of the unconverted 10% H2S) was 0.86 tons. This amount of SO{sub 2} is much lower than the normal 8 tons that would have been emitted if all of the H{sub 2}S were flared over the time of the pilot plant test. The pilot plant was simple to operate and required much less operator intervention than is typical for a new unit being commissioned. Our operator (Mr. Eugene Peeples) has more than 30 years of experience operating commercial scale liquid redox sulfur recovery processes and in his opinion, TDA's Direct Oxidation pilot plant is easier to operate than liquid systems. The ease of use and low capital and

  2. Generic process for preparing a crystalline oxide upon a group IV semiconductor substrate

    DOEpatents

    McKee, Rodney A.; Walker, Frederick J.; Chisholm, Matthew F.

    2000-01-01

    A process for growing a crystalline oxide epitaxially upon the surface of a Group IV semiconductor, as well as a structure constructed by the process, is described. The semiconductor can be germanium or silicon, and the crystalline oxide can generally be represented by the formula (AO).sub.n (A'BO.sub.3).sub.m in which "n" and "m" are non-negative integer repeats of planes of the alkaline earth oxides or the alkaline earth-containing perovskite oxides. With atomic level control of interfacial thermodynamics in a multicomponent semiconductor/oxide system, a highly perfect interface between a semiconductor and a crystalline oxide can be obtained.

  3. Advanced oxidation treatment of pulp mill effluent for TOC and toxicity removals.

    PubMed

    Catalkaya, Ebru Cokay; Kargi, Fikret

    2008-05-01

    Pulp mill effluent was treated by different advanced oxidation processes (AOPs) consisting of UV, UV/H2O2, TiO2-assisted photo-catalysis (UV/TiO2) and UV/H2O2/TiO2 in lab-scale reactors for total organic carbon (TOC) and toxicity removals. Effects of some operating parameters such as the initial pH, oxidant and catalyst concentrations on TOC and toxicity removals were investigated. Almost every method resulted in some degree of TOC and toxicity removal from the pulp mill effluent. However, the TiO2-assisted photo-catalysis (UV/TiO2) resulted in the highest TOC and toxicity removals under alkaline conditions when compared with the other AOPs tested. Approximately, 79.6% TOC and 94% toxicity removals were obtained by the TiO2-assisted photo-catalysis (UV/TiO2) with a titanium dioxide concentration of 0.75gl(-1) at pH 11 within 60min.

  4. Degradation and changes in toxicity and biodegradability of tetracycline during ozone/ultraviolet-based advanced oxidation.

    PubMed

    Luu, Huyen Trang; Lee, Kisay

    2014-01-01

    Advanced oxidation processes (AOPs) composed of O3, H2O2 and ultraviolet (UV) were applied to degrade tetracycline (TC). Degradation efficiency was evaluated in terms of changes in absorbance (ABS) and total organic carbon (TOC). The change in biotoxicity was monitored with Escherichia coli and Vibrio fischeri. The improvement in biodegradability during oxidation was demonstrated through 5-day biochemical oxygen demand/chemical oxygen demand ratio and aerobic biological treatment. The combination of O3/H2O2/UV and O3/UV showed the best performance for the reductions in ABS and TOC. However, mineralization and detoxification were not perfect under the experimental conditions that were used in this study. Therefore, for the ultimate treatment of TC compounds, it is suggested that AOP treatment is followed by biological treatment, utilizing enhanced biodegradability. In this study, aerobic biological treatment by Pseudomonas putida was performed for O3/UV-treated TC. It was confirmed that O3/UV treatment improved TOC reduction and facilitated complete mineralization in biological treatment.

  5. Nitrogen oxide removal dynamic process through 15 Ns DBD technique

    NASA Astrophysics Data System (ADS)

    Wang, Xiaojun; Zhang, Lianshui; Lai, Weidong; Liu, Fengliang

    2015-05-01

    Nitrogen oxides exhaust gas assumes the important responsibility on air pollution by forming acid rain. This paper discusses the NO removal mechanism in 15 ns pulse dielectric barrier discharge (DBD) plasma through experimental and simulating method. Emission spectra collected from plasma are evaluated as sourced from N+ and O(3P). The corresponding zero-dimensional model is established and verified through comparing the simulated concentration evolution and the experimental time-resolved spectra of N+. The electron impact ionization plays major role on NO removal and the produced NO+ are further decomposed into N+ and O(3P) through electron impact dissociative excitation rather than the usual reported dissociative recombination process. Simulation also indicates that the removal process can be accelerated by NO inputted at lower initial concentration or electrons streamed at higher concentration, due to the heightened electron impact probability on NO molecules. The repetitive pulse discharge is a benefit for improving the NO removal efficiency by effectively utilizing the radicals generated from the previous pulse under the condition that the pulse period should be shorter enough to ignore the spatial diffusion of radicals. Finally, slight attenuation on NO removal has been experimentally and simulatively observed after N2 mixed, due to the competitive consumption of electrons.

  6. Investigation of solution-processed bismuth-niobium-oxide films

    SciTech Connect

    Inoue, Satoshi; Ariga, Tomoki; Matsumoto, Shin; Onoue, Masatoshi; Miyasako, Takaaki; Tokumitsu, Eisuke; Shimoda, Tatsuya; Chinone, Norimichi; Cho, Yasuo

    2014-10-21

    The characteristics of bismuth-niobium-oxide (BNO) films prepared using a solution process were investigated. The BNO film annealed at 550°C involving three phases: an amorphous phase, Bi₃NbO₇ fluorite microcrystals, and Nb-rich cubic pyrochlore microcrystals. The cubic pyrochlore structure, which was the main phase in this film, has not previously been reported in BNO films. The relative dielectric constant of the BNO film was approximately 140, which is much higher than that of a corresponding film prepared using a conventional vacuum sputtering process. Notably, the cubic pyrochlore microcrystals disappeared with increasing annealing temperature and were replaced with triclinic β-BiNbO₄ crystals at 590°C. The relative dielectric constant also decreased with increasing annealing temperature. Therefore, the high relative dielectric constant of the BNO film annealed at 550°C is thought to result from the BNO cubic pyrochlore structure. In addition, the BNO films annealed at 500°C contained approximately 6.5 atm.% carbon, which was lost at approximately 550°C. This result suggests that the carbon in the BNO film played an important role in the formation of the cubic pyrochlore structure.

  7. Low-temperature oxidation of magnetite - a humidity sensitive process?

    NASA Astrophysics Data System (ADS)

    Appel, Erwin; Fang, Xiaomin; Herb, Christian; Hu, Shouyun

    2015-04-01

    Extensive multi-parameter palaeoclimate records were obtained from two long-term lacustrine archives at the Tibetan Plateau: the Qaidam basin (2.69-0.08 Ma) and Heqing basin (0.90-0.03 Ma). At present the region of the Qaidam site has an arid climate (<100 mm mean annual precipitation) while the Heqing site is located in the sub-tropical region with monsoonal rainfall. Magnetic properties play a prominent role for palaeoclimate interpretation in both records. Several parameters show a 100 kyr eccentricity cyclicity; in the Qaidam record also the Mid-Pleistocene Transition is seen. Both magnetic records are controlled by different absolute and relative contributions of magnetite and its altered (maghemitized) phases as well as hematite. Weathering conditions likely cause a systematic variation of magnetic mineralogy due to low-temperature oxidation (LTO). Maghemitization is well recognized as an alteration process in submarine basalts but about its relevance for climate-induced weathering in continental environments little is known. Various factors i.e., humidity, temperature, seasonality, duration of specific weathering conditions, and bacterial activity could be responsible for maghemitization (LTO) and transformation to hematite (or goethite) when a critical degree of LTO is reached. These factors may lead to a complex interplay, but one has to note that water acts as an electrolyte for Fe(II) to Fe(III) oxidation at the crystal surface and due to maghemitization-induced lattice shrinking a larger internal particle surface area becomes exposed to oxidation. We suggest that humidity is the most crucial driver for the two studied archives - for the following reasons: (1) The overall parameter variations and catchment conditions are well in agreement with an LTO scenario. (2) In the Qaidam record we observe a direct relationship of a humidity sensitive pollen Ratio with magnetic susceptibility (reflecting the degree of alteration by LTO). (3) In the Heqing record

  8. Integration of chemical-specific exposure and pharmacokinetic information with the chemical-agnostic AOP framework to support high throughput risk assessment

    EPA Science Inventory

    Application of the Adverse Outcome Pathway (AOP) framework and high throughput toxicity testing in chemical-specific risk assessment requires reconciliation of chemical concentrations sufficient to trigger a molecular initiating event measured in vitro and at the relevant target ...

  9. Development of computationally predicted Adverse Outcome Pathway (AOP) networks through data mining and integration of publicly available in vivo, in vitro, phenotype, and biological pathway data

    EPA Science Inventory

    The Adverse Outcome Pathway (AOP) framework is increasingly being adopted as a tool for organizing and summarizing the mechanistic information connecting molecular perturbations by environmental stressors with adverse outcomes relevant for ecological and human health outcomes. Ho...

  10. Ubiquitous anaerobic ammonium oxidation in inland waters of China: an overlooked nitrous oxide mitigation process

    PubMed Central

    Zhu, Guibing; Wang, Shanyun; Zhou, Leiliu; Wang, Yu; Zhao, Siyan; Xia, Chao; Wang, Weidong; Zhou, Rong; Wang, Chaoxu; Jetten, Mike S. M.; Hefting, Mariet M.; Yin, Chengqing; Qu, Jiuhui

    2015-01-01

    Denitrification has long been regarded as the only pathway for terrestrial nitrogen (N) loss to the atmosphere. Here we demonstrate that large-scale anaerobic ammonium oxidation (anammox), an overlooked N loss process alternative to denitrification which bypasses nitrous oxide (N2O), is ubiquitous in inland waters of China and contributes significantly to N loss. Anammox rates in aquatic systems show different levels (1.0–975.9 μmol N m−2 h−1, n = 256) with hotspots occurring at oxic-anoxic interfaces and harboring distinct biogeochemical and biogeographical features. Extrapolation of these results to the China-national level shows that anammox could contribute about 2.0 Tg N yr−1, which equals averagely 11.4% of the total N loss from China’s inland waters. Our results indicate that a significant amount of the nitrogen lost from inland waters bypasses denitrification, which is important for constructing more accurate climate models and may significantly reduce potential N2O emission risk at a large scale. PMID:26610807

  11. Ubiquitous anaerobic ammonium oxidation in inland waters of China: an overlooked nitrous oxide mitigation process.

    PubMed

    Zhu, Guibing; Wang, Shanyun; Zhou, Leiliu; Wang, Yu; Zhao, Siyan; Xia, Chao; Wang, Weidong; Zhou, Rong; Wang, Chaoxu; Jetten, Mike S M; Hefting, Mariet M; Yin, Chengqing; Qu, Jiuhui

    2015-11-27

    Denitrification has long been regarded as the only pathway for terrestrial nitrogen (N) loss to the atmosphere. Here we demonstrate that large-scale anaerobic ammonium oxidation (anammox), an overlooked N loss process alternative to denitrification which bypasses nitrous oxide (N2O), is ubiquitous in inland waters of China and contributes significantly to N loss. Anammox rates in aquatic systems show different levels (1.0-975.9 μmol N m(-2) h(-1), n = 256) with hotspots occurring at oxic-anoxic interfaces and harboring distinct biogeochemical and biogeographical features. Extrapolation of these results to the China-national level shows that anammox could contribute about 2.0 Tg N yr(-1), which equals averagely 11.4% of the total N loss from China's inland waters. Our results indicate that a significant amount of the nitrogen lost from inland waters bypasses denitrification, which is important for constructing more accurate climate models and may significantly reduce potential N2O emission risk at a large scale.

  12. Nitric oxide protects carbon assimilation process of watermelon from boron-induced oxidative injury.

    PubMed

    Farag, Mohamed; Najeeb, Ullah; Yang, Jinghua; Hu, Zhongyuan; Fang, Zhang Ming

    2017-02-01

    Nitric oxide (NO) mediates plant response to a variety of abiotic stresses; however, limited information is available on its effect on boron (B)-stressed watermelon plants. The present study investigates the mechanism through which NO protects watermelon seedlings from B deficiency and toxicity stresses. Five days old watermelon seedlings were exposed to B (0, 0.5 and 10 mg L(-1)) alone or with 75 μmole of NO donor sodium nitroprusside (SNP) for 30 days. Both low and high B concentrations in the media altered nutrient accumulation and impaired various physiological processes of watermelon seedlings, leading to a significant reduction in biomass production. The plants exposed to B deficient or toxic concentrations had 66 and 69% lower shoot dry weight, respectively compared with optimum B levels. B toxicity-induced growth inhibition of watermelon seedlings was associated with high B translocation to shoot tissues, which caused lipid membrane peroxidation (12% increase) and chlorophyll destruction (25% reduction). In contrast, B deficiency accelerated generation of reactive oxygen species (ROS), specifically OH(-1) and induced cellular oxidative injury. Exogenously applied SNP promoted leaf chlorophyll, photosynthesis and consequently biomass production in B-stressed watermelon seedlings by reducing B accumulation, lipid membrane peroxidation and ROS generation. It also activated antioxidant enzymes such as SOD, POD and APX, and protected the seedlings from ROS-induced cellular burst.

  13. Validation Test Report for the Automated Optical Processing System (AOPS) Version 4.12

    DTIC Science & Technology

    2015-09-03

    Orbiting Sensors project enables exploitation of the Visible Infrared Imager Radiometer Suite (VIIRS) and similar ocean color sensors to provide the Navy...of OBPG on- orbit vicarious calibration technique .................................................................................. 50 9.2 Pareto...Ocean Optical Products from Future Polar- Orbiting Sensors project enables exploitation of the Visible Infrared Imager Radiometer Suite (VIIRS) and

  14. Validation Test Report for the Automated Optical Processing System (AOPS) Version 4.10

    DTIC Science & Technology

    2015-08-25

    Preparing Tactical Ocean Optical Products from Future Polar- Orbiting Sensors project enables exploitation of the Visible Infrared Imager Radiometer Suite...produce operational products from the Joint Polar Orbiting System (JPSS) – Suomi National Polar- orbiting Partnership (NPP) with the VIIRS sensor...available through NOAA’s Comprehensive Large Array -data Stewardship System (CLASS) and Government Resource for Algorithm Verification, Independent

  15. Validation Test Report for the Automated Optical Processing System (AOPS) Version 4.8

    DTIC Science & Technology

    2013-06-28

    California roBert arnone University of Southern Mississippi Hattiesburg, Mississippi June 28, 2013 i REPORT DOCUMENTATION PAGE Form ApprovedOMB No. 0704...Stennis Space Center, MS 39529 ‡ San Diego State University, 720 Heber Ave, Calexico, CA 92231 §University of Southern Mississippi, 118 College Drive...1200 m of water, is the primary ocean observatory for vicarious calibration of satellite ocean color sensors. Since late 1996, it has been the

  16. Developing a Scalable Remote Sampling Design for the NEON Airborne Observation Platform (AOP)

    NASA Astrophysics Data System (ADS)

    Musinsky, J.; Wasser, L. A.; Kampe, T. U.; Leisso, N.; Krause, K.; Petroy, S. B.; Cawse-Nicholson, K.; van Aardt, J. A.; Serbin, S.

    2013-12-01

    The National Ecological Observatory Network (NEON) airborne observation platform (AOP) will collect co-registered high-resolution hyperspectral imagery, discrete and waveform LiDAR, and high-resolution digital photography for more than 60 terrestrial and 23 aquatic sites spread across the continental United States, Puerto Rico, Alaska and Hawaii on an annual basis over the next 30 years. These data, to be made freely available to the public, will facilitate the scaling of field-based biological, physical and chemical measurements to regional and continental scales, enabling a better understanding of the relationships between climate variability and change, land use change and invasive species, and their ecological consequences in areas not directly sampled by the NEON facilities. However, successful up-scaling of in situ measurements requires a flight sampling design that captures environmental heterogeneity and diversity (i.e., ecological and topographic gradients), is sensitive to temporal system variation (e.g., phenology), and can respond to major disturbance events. Alignment of airborne campaigns - composed of two payloads for nominal science acquisitions and one payload for PI-driven rapid-response campaigns -- with other ground, airborne (e.g., AVIRIS) and satellite (e.g., Landsat, MODIS) collections will further facilitate scaling between sensors and data sources of varying spatial and spectral resolution and extent. This presentation will discuss the approach, challenges and future goals associated with the development of NEON AOP's sampling design, using examples from the 2013 nominal flight campaigns in the Central Plains (NEON Domain 10) and the Pacific Southwest (Domain 17), and the rapid response flight campaign of the High Park Fire site outside of Fort Collins, CO. Determination of the specific flight coverage areas for each campaign involved analysis of the landscape scale ecological, geophysical and bioclimatic attributes and trends most closely

  17. Processing, characterization and properties of oxide based nanocomposites

    NASA Astrophysics Data System (ADS)

    Bhaduri, Sutapa

    The synthesis, characterization and mechanical properties of oxide based nanocomposites are reported in this dissertation. Two binary systems are studied: Alsb2Osb3-MgO and Alsb2Osb3-ZrOsb2. Alsb2Osb3-MgO was chosen because of its relatively large field of solid solubilities at a moderate temperature. On the other hand, Alsb2Osb3-ZrOsb2 was chosen because it shows minimal solid solubility of the constituents. A novel "Auto Ignition" process using suitable fuels and oxidizers was utilized in the synthesis of nanocomposites and solid solutions. Thermodynamic calculations were carried out in predicting end point adiabatic temperatures (Tsbad) for each composition in both systems. Combustion temperatures were experimentally measured by means of a data acquisition system. Characterizations of the powders were carried out by x-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive analysis (EDAX) and differential thermal analysis (DTA). Heat treatment experiments were carried out to study the grain growth behavior. A hot isostatic pressing (HIP) model was developed for the present nanoceramics. Input parameters were carefully chosen for such nanomaterials. The as-synthesized nanocrystalline powders were consolidated to near theoretical density by hot isostatic pressing (HIPing) while retaining fine grain size. The experimental results were compared with the predictions of the model. Mechanical properties, such as room temperature toughness, low temperatures well as high temperature hardness, were determined for both systems. Room temperature hardness values were (2.89-7.79) GPa and fracture toughness was between 2.7 and 5.82 MPa.msp{1/2} for various compositions in the Alsb2Osb3-MgO system. Room temperature hardness values were between 5.33 and 8.71 GPa and fracture toughness values ranged from (5.3-9.62) MPa.msp{1/2} for various compositions in the Alsb2Osb3-ZrOsb2 system. Nanoindentation experiments were carried out to further explore the room

  18. Electrochemical Interfaces and Electrode Processes: Electrochemical Oxidation of Small Organisms

    DTIC Science & Technology

    1994-09-01

    Reduction on Poly(4- Vinylpyridine)-Modified Ordinary Pyrolytic Graphite Electrodes with Adsorbed Cobalt Tetrasulfonated Phthalocyanine in Acid ...cobalt tetrasulfonated phthalocyanine (CoTsPc) does not adsorb strongly on the (Li)NiO oxide or other oxides such as tin-doped indium oxide (ITO). The...interpretation of the STM and AFM results. The Co- and Fe- tetrasulfonated phthalocyanines (TsPc) adsorbed on an HOPG surface were studied by cyclic

  19. Treatment of real effluents from the pharmaceutical industry: A comparison between Fenton oxidation and conductive-diamond electro-oxidation.

    PubMed

    Pérez, J F; Llanos, J; Sáez, C; López, C; Cañizares, P; Rodrigo, M A

    2016-08-13

    Wastewater produced in pharmaceutical manufacturing plants (PMPs), especially the one coming from organic-synthesis facilities, is characterized by its large variability due to the wide range of solvents and chemical reagents used in the different stages of the production of medicines. Normally, the toxicity of the organic compounds prevent the utilization of biological processes and more powerful treatments are needed becoming advanced oxidation processes (AOPs) a valid alternative. In this work, the efficiency in abatement of pollution by Fenton oxidation (FO) and conductive-diamond electro-oxidation (CDEO) are compared in the treatment of 60 real effluents coming from different processes carried out in a pharmaceutical facility, using standardized tests. In 80% of the samples, CDEO was found to be more efficient than FO and in the remaining 20%, coagulation was found to exhibit a great significance in the COD abatement mechanism during FO, pointing out the effectiveness of the oxidation promoted by the electrochemical technology. Mean oxidation state of carbon was found to be a relevant parameter to understand the behavior of the oxidation technologies. It varied inversely proportional to efficiency in FO and it showed practically no influence in the case of CDEO.

  20. Effects of Gravity on Supercritical Water Oxidation (SCWO) Processes

    NASA Technical Reports Server (NTRS)

    Hegde, Uday; Hicks, Michael

    2013-01-01

    The effects of gravity on the fluid mechanics of supercritical water jets are being studied at NASA to develop a better understanding of flow behaviors for purposes of advancing supercritical water oxidation (SCWO) technologies for applications in reduced gravity environments. These studies provide guidance for the development of future SCWO experiments in new experimental platforms that will extend the current operational range of the DECLIC (Device for the Study of Critical Liquids and Crystallization) Facility on board the International Space Station (ISS). The hydrodynamics of supercritical fluid jets is one of the basic unit processes of a SCWO reactor. These hydrodynamics are often complicated by significant changes in the thermo-physical properties that govern flow behavior (e.g., viscosity, thermal conductivity, specific heat, compressibility, etc), particularly when fluids transition from sub-critical to supercritical conditions. Experiments were conducted in a 150 ml reactor cell under constant pressure with water injections at various flow rates. Flow configurations included supercritical jets injected into either sub-critical or supercritical water. Profound gravitational influences were observed, particularly in the transition to turbulence, for the flow conditions under study. These results will be presented and the parameters of the flow that control jet behavior will be examined and discussed.

  1. Process for oxidation of hydrogen halides to elemental halogens

    DOEpatents

    Lyke, Stephen E.

    1992-01-01

    An improved process for generating an elemental halogen selected from chlorine, bromine or iodine, from a corresponding hydrogen halide by absorbing a molten salt mixture, which includes sulfur, alkali metals and oxygen with a sulfur to metal molar ratio between 0.9 and 1.1 and includes a dissolved oxygen compound capable of reacting with hydrogen halide to produce elemental halogen, into a porous, relatively inert substrate to produce a substrate-supported salt mixture. Thereafter, the substrate-supported salt mixture is contacted (stage 1) with a hydrogen halide while maintaining the substrate-supported salt mixture during the contacting at an elevated temperature sufficient to sustain a reaction between the oxygen compound and the hydrogen halide to produce a gaseous elemental halogen product. This is followed by purging the substrate-supported salt mixture with steam (stage 2) thereby recovering any unreacted hydrogen halide and additional elemental halogen for recycle to stage 1. The dissolved oxygen compound is regenerated in a high temperature (stage 3) and an optical intermediate temperature stage (stage 4) by contacting the substrate-supported salt mixture with a gas containing oxygen whereby the dissolved oxygen compound in the substrate-supported salt mixture is regenerated by being oxidized to a higher valence state.

  2. Activation of Peroxymonosulfate by Benzoquinone: A Novel Nonradical Oxidation Process.

    PubMed

    Zhou, Yang; Jiang, Jin; Gao, Yuan; Ma, Jun; Pang, Su-Yan; Li, Juan; Lu, Xue-Ting; Yuan, Li-Peng

    2015-11-03

    The reactions between peroxymonosulfate (PMS) and quinones were investigated for the first time in this work, where benzoquinone (BQ) was selected as a model quinone. It was demonstrated that BQ could efficiently activate PMS for the degradation of sulfamethoxazole (SMX; a frequently detected antibiotic in the environments), and the degradation rate increased with solution pH from 7 to 10. Interestingly, quenching studies suggested that neither hydroxyl radical (•OH) nor sulfate radical (SO4•-) was produced therein. Instead, the generation of singlet oxygen (1O2) was proved by using two chemical probes (i.e., 2,2,6,6-tetramethyl-4-piperidinol and 9,10-diphenylanthracene) with the appearance of 1O2 indicative products detected by electron paramagnetic resonance spectrometry and liquid chromatography mass spectrometry, respectively. A catalytic mechanism was proposed involving the formation of a dioxirane intermediate between PMS and BQ and the subsequent decomposition of this intermediate into 1O2. Accordingly, a kinetic model was developed, and it well described the experimental observation that the pH-dependent decomposition rate of PMS was first-order with respect to BQ. These findings have important implications for the development of novel nonradical oxidation processes based on PMS, because 1O2 as a moderately reactive electrophile may suffer less interference from background organic matters compared with nonselective •OH and SO4•-.

  3. SOS processing of unique oxidative DNA damages in Escherichia coli.

    PubMed

    Laspia, M F; Wallace, S S

    1989-05-05

    phi X174 replicative form (RF) I transfecting DNA containing thymine glycols (5,6-dihydroxy-5,6-dihydrothymine), urea glycosides or apurinic (AP) sites was used to study SOS processing of unique DNA damages in Escherichia coli. All three lesions can be found in DNA damaged by chemical oxidants or radiation and are representative of several common structural modifications of DNA bases. When phi X DNA containing thymine glycols was transfected into host cells that were ultraviolet-irradiated to induce the SOS response, a substantial increase in survival was observed compared to transfection into uninduced hosts. Studies with mutants demonstrated that both the activated form of RecA and UmuDC proteins were required for this reactivation. In contrast, no increase in survival was observed when DNA containing urea glycosides or AP sites was transfected into ultraviolet-induced hosts. These data suggest that SOS-induced reactivation does not reflect a generalized repair system for all replication-blocking, lethal lesions but rather that the efficiency of reactivation is damage dependent. Further, we found that a significant fraction of potentially lethal thymine glycols could be ultraviolet-reactivated in an umuC lexA recA-independent manner, suggesting the existence of an as yet uncharacterized damage-inducible SOS-independent mode of thymine glycol repair.

  4. Fabrication of Glassy and Crystalline Ferroelectric Oxide by Containerless Processing

    NASA Astrophysics Data System (ADS)

    Yoda, Shinichi

    1. Instruction Much effort has been devoted to forming bulk glass from the melt of ferroelectric crystalline materials without adding any network-forming oxides such as SiO2 due to the potential for producing transparent glass ceramics with high dielectric constant and enhanced piezoelectric, pyroelectric and electro-optic effects. However, they require a higher cooling rate than glass formed by conventional techniques. Therefore, only amorphous thin-films have been formed, using rapid quenching with a cooling rate >105 K/s. The containerless processing is an attractive synthesis technique as it can prevent melt contamination, minimize heterogeneous nucleation, and allow melt to achieve deep undercooling for forming metastable phase and glassy material. Recently a new ferroelectric materiel, monoclinic BaTi2 O5 , with Currie temperature as 747 K was reported. In this study, we fabricated a bulk BaTi2 O5 glass from melt using containerless processing to study the phase relations and ferroelectric properties of BaTi2 O5 . To our knowledge, this was the first time that a bulk glass of ferroelectric material was fabricated from melt without adding any network-forming oxide. 2. Experiments BaTi2 O5 sphere glass with 2mm diameter was fabricated using containerless processing in an Aerodynamic Levitation Furnace (ALF). The containerless processing allowed the melt to achieve deep undercooling for glass forming. High purity commercial BaTiO3 and TiO2 powders were mixed with a mole ratio of 1:1 and compressed into rods and then sintered at 1427 K for 10 h. Bulk samples with a mass of about 20 mg were cut from the rod, levitated with the ALF, and then melted by a CO2 laser beam. After quenching with a cooling rate of about 1000 K/s, 2 mm diameter sphere glass could be obtained. To analyze the glass structure, a high-energy x-ray diffraction experiment was performed using an incident photon energy of 113.5 keV at the high-energy x-ray diffraction beamline BL04B2 of SPring-8

  5. Nanocrystalline-oxide ceramics: Synthesis, diagnostics, and processing

    NASA Astrophysics Data System (ADS)

    Chen, Yi-Jia

    A flat-flame combustion process is employed to synthesize oxide-ceramic powder with nanoparticle size. An extensive study is made of the influence of processing parameters on final particle size. The parameters include precursor feed rate, burner-to-chill distance, chamber pressure, and location in the reaction chamber. Laser induced fluorescence is used as an in-situ diagnostic tool to obtain information on precursor concentration, the extent of precursor decomposition, particle formation, and temperature profiles. It is found that the precursor feed rate affects the precursor decomposition rate, and that most of the precursor decomposition is complete at one third of the burner-to-chill distance. Evidence for nanoparticle formation, which immediately follows precursor decomposition, is obtained from visible light emission. The effect of the chill is to establish a fixed aspect ratio (burner diameter to burner-to-chill distance) and to ensure one-dimensional flow. Decomposition of the precursor is complete within the stand-off distance, while particle coalescence is the main feature outside the burner region. A non-agglomerated nanopowder with particle size ranging from several to tens of nanometers is easily obtained using the flat-flame combustion process. After the optimum powder processing conditions are established, the as-synthesized powder is collected and used as starting material for a sintering study. A torroidal type of high pressure apparatus is used to sinter the green compacts, using a wide range of sintering conditions up to 8GPa and 2000°C. To sinter the nanopowder into single-phase material, while maintaining nano-sized grains, pressures in the GPa range are required to close the pores, because of the small pore size and associated high curvature. In the sintering of nanoparticles involving a phase transformation, accompanied by a reduced molar volume, pressure acts as a nucleation promoter. By applying high pressure, the sintering temperature is

  6. Design of the Laboratory-Scale Plutonium Oxide Processing Unit in the Radiochemical Processing Laboratory

    SciTech Connect

    Lumetta, Gregg J.; Meier, David E.; Tingey, Joel M.; Casella, Amanda J.; Delegard, Calvin H.; Edwards, Matthew K.; Orton, Robert D.; Rapko, Brian M.; Smart, John E.

    2015-05-01

    This report describes a design for a laboratory-scale capability to produce plutonium oxide (PuO2) for use in identifying and validating nuclear forensics signatures associated with plutonium production, as well as for use as exercise and reference materials. This capability will be located in the Radiochemical Processing Laboratory at the Pacific Northwest National Laboratory. The key unit operations are described, including PuO2 dissolution, purification of the Pu by ion exchange, precipitation, and re-conversion to PuO2 by calcination.

  7. High ethylene to ethane processes for oxidative coupling

    DOEpatents

    Chafin, Richard B.; Warren, Barbara K.

    1991-01-01

    Oxidative coupling of lower alkane to higher hydrocarbon is conducted using catalyst comprising barium and/or strontium component and a metal oxide combustion promoter in the presence of vapor phase halogen component. High ethylene to ethane mole ratios in the product can be obtained over extended operating periods.

  8. High ethylene to ethane processes for oxidative coupling

    DOEpatents

    Chafin, R.B.; Warren, B.K.

    1991-12-17

    Oxidative coupling of lower alkane to higher hydrocarbon is conducted using a catalyst comprising barium and/or strontium component and a metal oxide combustion promoter in the presence of vapor phase halogen component. High ethylene to ethane mole ratios in the product can be obtained over extended operating periods.

  9. Removal of emerging contaminants in sewage water subjected to advanced oxidation with ozone.

    PubMed

    Ibáñez, M; Gracia-Lor, E; Bijlsma, L; Morales, E; Pastor, L; Hernández, F

    2013-09-15

    Advanced oxidation processes (AOP) based on ozone treatments, assisted by ultrasounds, have been investigated at a pilot-plant scale in order to evaluate the removal of emerging contaminants in sewage water. Around 60 emerging contaminants, mainly pharmaceuticals from different therapeutically classes and drugs of abuse, have been determined in urban wastewater samples (treated and untreated) by LC-MS/MS. In a first step, the removal efficiency of these contaminants in conventional sewage water treatment plants was evaluated. Our results indicate that most of the compounds were totally or partially removed during the treatment process of influent wastewater. Up to 30 contaminants were quantified in the influent and effluent samples analysed, being antibiotics, anti-inflammatories, cholesterol lowering statin drugs and angiotensin II receptor antagonists the most frequently detected. Regarding drugs of abuse, cocaine and its metabolite benzoylecgonine were the most frequent. In a second step, the effectiveness of AOP in the removal of emerging contaminants remaining in the effluent was evaluated. Ozone treatments have been proven to be highly efficient in the removal, notably decreasing the concentrations for most of the emerging contaminants present in the water samples. The use of ultrasounds, alone or assisting ozone treatments, has been shown less effective, being practically unnecessary.

  10. Development Studies for a Novel Wet Oxidation Process

    SciTech Connect

    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

  11. Optimizing the treatment of landfill leachate by conventional Fenton and photo-Fenton processes.

    PubMed

    Hermosilla, Daphne; Cortijo, Manuel; Huang, Chin Pao

    2009-05-15

    Landfill, a matured and economically appealing technology, is the ultimate approach for the management of municipal solid wastes. However, the inevitable generation of leachate from landfill requires further treatment. Among the various leachate treatment technologies available, advanced oxidation processes (AOPs) are among powerful methods to deal with the refractory organic constituents, and the Fenton reagent has evolved as one promising AOPs for the treatment of leachates. Particularly, the combination of UV-radiation with Fenton's reagent has been reported to be a method that allows both the photo-regeneration of Fe(2+) and photo-decarboxylation of ferric carboxylates. In this study, Fenton and photo-Fenton processes were fine tuned for the treatment of leachates from the Colmenar Viejo (Madrid, Spain) Landfill. Results showed that it is possible to define a set of conditions under which the same COD and TOC removals (approximately 70%) could be achieved with both the conventional and photo-Fenton processes. But Fenton process generated an important quantity of iron sludge, which will require further disposal, when performed under optimal COD removal conditions. Furthermore conventional Fenton process was able to achieve slightly over an 80% COD removal from a "young" leachate, while for "old" and "mixed" leachates was close to a 70%. The main advantage showed by the photo-assisted Fenton treatment of landfill leachate was that it consumed 32 times less iron and produced 25 times less sludge volume yielding the same COD removal results than a conventional Fenton treatment.

  12. Integrated oxidation membrane filtration process - NOM rejection and membrane fouling.

    PubMed

    Winter, J; Uhl, W; Bérubé, P R

    2016-11-01

    The extent and mechanisms by which organic matter in a solution can be retained and foul a membrane largely depends on the molecular weight of the material being filtered and the molecular weight cut-off (MWCO) of the membrane. The present study investigated the effect of the MWCO of a membrane and the molecular weight distribution of natural organic matter (NOM) in a source water on the increase in resistance to the permeate flux over time. Of particular interest was the effect of oxidation, applied prior to membrane filtration, on the predominant fouling mechanism. Oxidation can change the molecular weight distribution of organic matter in raw water, and therefore the ability of a membrane to retain this organic matter. Oxidation, using both ozonation and UV/H2O2, could effectively reduce the extent of fouling for higher MWCO membranes. However, neither oxidation approaches could effectively reduce the extent of fouling for lower MWCO membranes, likely because oxidation could not effectively oxidize lower molecular weight organic matter. Althoug the data indicated that the extent of fouling is increasing with the amount of DOC retained by the membrane, no statistically significant correlation was observed between these parameters. The results suggest that oxidation did not affect the predominant fouling mechanism. However, it did affect the molecular weight distribution of the organic matter retained by the membranes, and as a result, the resistance offered by the foulant cake layer.

  13. Fabrication of MnO 2-pillared layered manganese oxide through an exfoliation/reassembling and oxidation process

    NASA Astrophysics Data System (ADS)

    Yuan, Jiaqi; Liu, Zong-Huai; Qiao, Shanfeng; Ma, Xiangrong; Xu, Naicai

    MnO 2-pillared layered manganese oxide has been first fabricated by a delamination/reassembling process followed by oxidation reaction and then by heat treatment. The structural evolution of MnO 2-pillared layered manganese oxide has been characterized by XRD, SEM, DSC-GTA, IR and N 2 adsorption-desorption. MnO 2-pillared layered manganese oxide shows a relative high thermal stability and mesoporous characteristic. The layered structure with a basal spacing of 0.66 nm could be maintained up to 400 °C. The electrochemical properties of the synthesized MnO 2-pillared layered manganese oxide have been studied using cyclic voltammetry in a mild aqueous electrolyte. Sample MnO 2-BirMO (300 °C) shows good capacitive behavior and cycling stability, and the specific capacitance value is 206 F g -1.

  14. Comparison of AOPs for the removal of natural organic matter: performance and economic assessment.

    PubMed

    Murray, C A; Parsons, S A

    2004-01-01

    Control of disinfection by-products during water treatment is primarily achieved by reducing the levels of organic precursor species prior to chlorination. Many waters contain natural organic matter at levels up to 15 mg L(-1); therefore it is necessary to have a range of control methods to support conventional coagulation. Advanced oxidation processes are such processes and in this paper the Fenton and photo-Fenton processes along with photocatalysis are assessed for their NOM removal potential. The performance of each process is shown to be dependent on pH and chemical dose as well as the initial NOM concentration. Under optimum conditions the processes achieved greater than 90% removal of DOC and UV254 absorbance. This removal led to the THMFP of the source water being reduced from 140 to below 10 microg L(-1), well below UK and US standards. An economic assessment of the processes revealed that currently such processes are not economic. With advances in technology and tightening of water quality standards these processes should become economically feasible options.

  15. Fenton's oxidation process for phenolic wastewater remediation and biodegradability enhancement.

    PubMed

    Martins, Rui C; Rossi, André F; Quinta-Ferreira, Rosa M

    2010-08-15

    A mixture of six phenolic acids, corresponding to an initial TOC of 370 mgC/L, was studied by Fenton's peroxidation aiming to improve the biodegradability of agro-industrial wastewaters. Input operating variables including the concentration of pollutants, iron and hydrogen peroxide as well as the reaction time were used to assess the mineralization degree through a factorial experimental methodology. A TOC removal in the range of 15.0-58.8% was attained within the operational conditions used. A reduced model was achieved using the statistically important independent factors and interactions to predict TOC degradation. On the hydrogen peroxide injection methodology, the results showed that the continuous introduction of small volumes is advantageous when compared with one single addition of the overall volume at the zero reaction time with a mineralization improvement of 11%. The use of FeSO(4).7H(2)O correspondent to a Fe(2+) load of 271 mg; [H(2)O(2)]=488.0 mM, injected in twelve aliquots each 30 min during 6h of reaction reached optimal efficiencies with the parent compounds (quantified by HPLC and the Folin-Ciocalteau method) quickly totally removed and TOC, COD and BOD(5) final values of 123 mgC/L, 180 mgO(2)/L and 146 mgO(2)/L, respectively. Toxicity assessment by Vibrio fischeri light inhibition revealed that Fenton's process reduces the effluent ecological impact related with the decomposition of the toxic phenolic acids. Indeed, EC(50) changed from 32.2% dilution to no-dilution needed. The analysis of BOD(5)/COD ratio pointed out a high improvement of the treated wastewater biodegradability from 0.30 to 0.80 meaning that the application of Fenton's oxidation as a pre-treatment enables a further application of an efficient post-biological technology which was also confirmed by respirometry.

  16. Thermally grown oxide and diffusions for automatic processing of integrated circuits

    NASA Technical Reports Server (NTRS)

    Kennedy, B. W.

    1979-01-01

    A totally automated facility for semiconductor oxidation and diffusion was developed using a state-of-the-art diffusion furnace and high temperature grown oxides. Major innovations include: (1) a process controller specifically for semiconductor processing; (2) an automatic loading system to accept wafers from an air track, insert them into a quartz carrier and then place the carrier on a paddle for insertion into the furnace; (3) automatic unloading of the wafers back onto the air track, and (4) boron diffusion using diborane with plus or minus 5 percent uniformity. Processes demonstrated include Wet and dry oxidation for general use and for gate oxide, boron diffusion, phosphorous diffusion, and sintering.

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

    EPA Science Inventory

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

  18. Process for making a noble metal on tin oxide catalyst

    NASA Technical Reports Server (NTRS)

    Upchurch, Billy T. (Inventor); Davis, Patricia (Inventor); Miller, Irvin M. (Inventor)

    1989-01-01

    A quantity of reagent grade tin metal or compound, chloride-free, and high-surface-area silica spheres are placed in deionized water, followed by deaerating the mixture by boiling and adding an oxidizing agent, such as nitric acid. The nitric acid oxidizes the tin to metastannic acid which coats the spheres because the acid is absorbed on the substrate. The metastannic acid becomes tin oxide upon drying and calcining. The tin-oxide coated silica spheres are then placed in water and boiled. A chloride-free precious metal compound in aqueous solution is then added to the mixture containing the spheres, and the precious metal compound is reduced to a precious metal by use of a suitable reducing agent such as formic acid. Very beneficial results were obtained using the precious metal compound tetraammine platinum(II) hydroxide.

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

    DOEpatents

    Shelnutt, John A.

    1990-01-01

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

  20. ALCOHOL OXIDATION - A COMPARATIVE STUDY OF DIFFERENT CATALYTIC PROCESSES

    EPA Science Inventory

    Oxidation of alcohols to aldehydes, ketones or carboxylic acids is one of the most desirable chemical transformations in organic synthesis as these products are important precursors and intermediates for many drugs, vitamins and fragrances. Numerous methods are available for alco...

  1. SELECTIVE OXIDATION OF ALCOHOLS - COMPARING DIFFERENT CATALYTIC PROCESSES

    EPA Science Inventory

    Oxidation of alcohols to aldehydes, ketones or carboxylic acids is one of the most desirable chemical transformations in organic synthesis as these products are important precursors and intermediates for many drugs, vitamins and fragrances. Numerous methods are available for alc...

  2. The role of oxidation in the fretting wear process

    NASA Technical Reports Server (NTRS)

    Bill, R. C.

    1980-01-01

    Fretting experiments were conducted on titanium, a series of Ni-Cr-Al alloys and on some high temperature turbine alloys at room temperature and at elevated temperatures in air and in various inert environments. It was found that, depending on temperature and environment, the fretting behavior of the materials examined could be classified according to four general types of behavior. Briefly, these types of behavior were: (1) the complete absence of oxidation, as in inert environments, generally leading to low rates of fretting wear but high fretting friction; (2) gradual attrition of surface oxide with each fretting stroke, found in these experiments to operate in concert with other dominating mechanisms; (3) rapid oxidation at surface fatigue damage sites, resulting in undermining and rapid disintegration of the load bearing surface; and (4) the formation of coherent, protective oxide film, resulting in low rates of fretting wear. An analytical model predicting conditions favorable to the fourth type of behavior was outlined.

  3. Removal of the anti-cancer drug methotrexate from water by advanced oxidation processes: Aerobic biodegradation and toxicity studies after treatment.

    PubMed

    Lutterbeck, Carlos Alexandre; Baginska, Ewelina; Machado, Ênio Leandro; Kümmerer, Klaus

    2015-12-01

    Anti-cancer drugs are discussed as high risk substances in regard to human health and considered as problematic for the environment. They are of potential environmental relevance due to their poor biodegradability and toxicological properties. Methotrexate (MTX) is an antimetabolite that was introduced in the pharmaceutical market in the 40's and still today is one of the most consumed cytotoxic compounds around the world. In the present study MTX was only partially biodegraded in the closed bottle test (CBT). Therefore, it was submitted to three different advanced oxidation processes (AOPs): UV/H2O2, UV/Fe(2+)/H2O2 and UV/TiO2. The irradiation was carried out with a Hg medium-pressure lamp during 256min whereas the analytical monitoring was done through LC-UV-MS/MS and DOC analysis. MTX was easily removed in all the irradiation experiments, while the highest mineralization values and rates were achieved by the UV/Fe(2+)/H2O2 treatment. The lowest resulted from the UV/H2O2 reactions. The UV/H2O2 treatment resulted in little biodegradable transformation products (TPs). However, the same treatment resulted in a reduction of the toxicity of MTX by forming less toxic TPs. Analysis by LC-UV-MS/MS revealed the existence of nine TPs formed during the photo-catalytic treatments. The pH of the solutions decreased from 6.4 (t 0min) to 5.15 in the UV/H2O2 and from 6.4 (t 0min) to 5.9 in the UV/TiO2 at the end of the experiments. The initial pH of the UV/Fe(2+)/H2O2 experiments was adjusted to 5 and after the addition of H2O2 the pH decreased to around 3 and remained in this range until the end of the treatments.

  4. Process for treating effluent from a supercritical water oxidation reactor

    DOEpatents

    Barnes, C.M.; Shapiro, C.

    1997-11-25

    A method for treating a gaseous effluent from a supercritical water oxidation reactor containing entrained solids is provided comprising the steps of expanding the gas/solids effluent from a first to a second lower pressure at a temperature at which no liquid condenses; separating the solids from the gas effluent; neutralizing the effluent to remove any acid gases; condensing the effluent; and retaining the purified effluent to the supercritical water oxidation reactor. 6 figs.

  5. Process for treating effluent from a supercritical water oxidation reactor

    DOEpatents

    Barnes, Charles M.; Shapiro, Carolyn

    1997-01-01

    A method for treating a gaseous effluent from a supercritical water oxidation reactor containing entrained solids is provided comprising the steps of expanding the gas/solids effluent from a first to a second lower pressure at a temperature at which no liquid condenses; separating the solids from the gas effluent; neutralizing the effluent to remove any acid gases; condensing the effluent; and retaining the purified effluent to the supercritical water oxidation reactor.

  6. Formation of porous metal oxides in the anodization process.

    PubMed

    Sample, C; Golovin, A A

    2006-10-01

    A theory of the formation of nanoscale porous structures in oxides of metals grown by anodization is developed. It is shown that a growing oxide layer can become unstable which yields the formation of a spatially irregular array of pores. The instability is shown to result from a nonlinear dependence of electrochemical kinetics at the metal-oxide and oxide-electrolyte interfaces on the overpotential which is governed by the Butler-Volmer relation. The conditions for the instability of the oxide layer are found. The dependence of the oxide conductivity on the electric field is taken into account and is shown to have a destabilizing effect. A weakly nonlinear analysis is performed and it shows that the system evolution near the instability threshold is described by the Kuramoto-Sivashinsky equation. Farther from threshold, in the long-wave approximation, a system of strongly nonlinear equations is derived and solved numerically; this system describes the formation of deep irregular pores. In a particular case, a self-similar solution describing the propagation of a pore with a paraboloidal shape is found.

  7. p-Channel oxide thin film transistors using solution-processed copper oxide.

    PubMed

    Kim, Sang Yun; Ahn, Cheol Hyoun; Lee, Ju Ho; Kwon, Yong Hun; Hwang, Sooyeon; Lee, Jeong Yong; Cho, Hyung Koun

    2013-04-10

    Cu2O thin films were synthesized on Si (100) substrate with thermally grown 200-nm SiO2 by sol-gel spin coating method and postannealing under different oxygen partial pressure (0.04, 0.2, and 0.9 Torr). The morphology of Cu2O thin films was improved through N2 postannealing before O2 annealing. Under relatively high oxygen partial pressure of 0.9 Torr, the roughness of synthesized films was increased with the formation of CuO phase. Bottom-gated copper oxide (CuxO) thin film transistors (TFTs) were fabricated via conventional photolithography, and the electrical properties of the fabricated TFTs were measured. The resulting Cu2O TFTs exhibited p-channel operation, and field effect mobility of 0.16 cm2/(V s) and on-to-off drain current ratio of ∼1×10(2) were observed in the TFT device annealed at PO2 of 0.04 Torr. This study presented the potential of the solution-based process of the Cu2O TFT with p-channel characteristics for the first time.

  8. Process for Making a Noble Metal on Tin Oxide Catalyst

    NASA Technical Reports Server (NTRS)

    Davis, Patricia; Miller, Irvin; Upchurch, Billy

    2010-01-01

    To produce a noble metal-on-metal oxide catalyst on an inert, high-surface-area support material (that functions as a catalyst at approximately room temperature using chloride-free reagents), for use in a carbon dioxide laser, requires two steps: First, a commercially available, inert, high-surface-area support material (silica spheres) is coated with a thin layer of metal oxide, a monolayer equivalent. Very beneficial results have been obtained using nitric acid as an oxidizing agent because it leaves no residue. It is also helpful if the spheres are first deaerated by boiling in water to allow the entire surface to be coated. A metal, such as tin, is then dissolved in the oxidizing agent/support material mixture to yield, in the case of tin, metastannic acid. Although tin has proven especially beneficial for use in a closed-cycle CO2 laser, in general any metal with two valence states, such as most transition metals and antimony, may be used. The metastannic acid will be adsorbed onto the high-surface-area spheres, coating them. Any excess oxidizing agent is then evaporated, and the resulting metastannic acid-coated spheres are dried and calcined, whereby the metastannic acid becomes tin(IV) oxide. The second step is accomplished by preparing an aqueous mixture of the tin(IV) oxide-coated spheres, and a soluble, chloride-free salt of at least one catalyst metal. The catalyst metal may be selected from the group consisting of platinum, palladium, ruthenium, gold, and rhodium, or other platinum group metals. Extremely beneficial results have been obtained using chloride-free salts of platinum, palladium, or a combination thereof, such as tetraammineplatinum (II) hydroxide ([Pt(NH3)4] (OH)2), or tetraammine palladium nitrate ([Pd(NH3)4](NO3)2).

  9. A review of greywater characteristics and treatment processes.

    PubMed

    Boyjoo, Yash; Pareek, Vishnu K; Ang, Ming

    2013-01-01

    This paper presents a comprehensive literature review of different characteristics of greywater (GW) and current treatment methods. GW is domestic wastewater excluding toilet waste and can be classified as either low-load GW (excluding kitchen and laundry GW) or high-load GW (including kitchen and/or laundry). This review provides information on the quantity of GW produced, its constituents (macro and micro), existing guidelines for wastewater reuse, current treatment methods (from storage to disinfection) as well as related costs and environmental impacts. Moreover some successful examples from various countries around the world are examined. The current preferred treatments for GW use physical and biological/natural systems. Recently, chemical systems like coagulation, adsorption and advanced oxidation processes (AOPs) have been considered and have been successful for low to moderate strength GW. The presence of xenobiotic organic compounds (XOC), which are hazardous micropollutants in GW, is emphasised. Since conventional treatments are not efficient at removing XOC, it is recommended that future studies look at chemical treatment, especially AOPs that have been found to be successful at mineralising recalcitrant organic compounds in wastewater.

  10. Electrospinning of nickel oxide nanofibers: Process parameters and morphology control

    SciTech Connect

    Khalil, Abdullah Hashaikeh, Raed

    2014-09-15

    In the present work, nickel oxide nanofibers with varying morphology (diameter and roughness) were fabricated via electrospinning technique using a precursor composed of nickel acetate and polyvinyl alcohol. It was found that the diameter and surface roughness of individual nickel oxide nanofibers are strongly dependent upon nickel acetate concentration in the precursor. With increasing nickel acetate concentration, the diameter of nanofibers increased and the roughness decreased. An optimum concentration of nickel acetate in the precursor resulted in the formation of smooth and continuous nickel oxide nanofibers whose diameter can be further controlled via electrospinning voltage. Beyond an optimum concentration of nickel acetate, the resulting nanofibers were found to be ‘flattened’ and ‘wavy’ with occasional cracking across their length. Transmission electron microscopy analysis revealed that the obtained nanofibers are polycrystalline in nature. These nickel oxide nanofibers with varying morphology have potential applications in various engineering domains. - Highlights: • Nickel oxide nanofibers were synthesized via electrospinning. • Fiber diameter and roughness depend on nickel acetate concentration used. • With increasing nickel acetate concentration the roughness of nanofibers decreased. • XRD and TEM revealed a polycrystalline structure of the nanofibers.

  11. CHEMISTRY OF SO2 AND DESOX PROCESSES ON OXIDE NANOPARTICLES.

    SciTech Connect

    RODRIGUEZ, J.A.

    2006-06-30

    On bulk stoichiometric oxides, SO{sub 2} mainly reacts with the O centers to form SO{sub 3} or SO{sub 4} species that decompose at elevated temperatures. Adsorption on the metal cations occurs below 300 K and does not lead to cleavage of the S-O bonds. In bulk oxides, the occupied cation bands are too stable for effective bonding interactions with the LUMO of SO{sub 2}. The effects of quantum confinement on the electronic properties of oxide nanoparticles and the structural defects that usually accompany these systems in general favor the bonding and dissociation of SO{sub 2}. Thus, nanoparticles of MgO, CaO, SrO, Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3} and CeO{sub 2} are all more efficient for sequestering SO{sub 2} than the corresponding bulk oxides. Structural imperfections in pure or metal-doped ceria nanoparticles accelerate the reduction of SO{sub 2} by CO by facilitating the formation and migration of O vacancies in the oxide surface.

  12. Degradation mechanism of cyanobacterial toxin cylindrospermopsin by hydroxyl radicals in homogeneous UV/H₂O₂ process.

    PubMed

    He, Xuexiang; Zhang, Geshan; de la Cruz, Armah A; O'Shea, Kevin E; Dionysiou, Dionysios D

    2014-04-15

    The degradation of cylindrospermopsin (CYN), a widely distributed and highly toxic cyanobacterial toxin (cyanotoxin), remains poorly elucidated. In this study, the mechanism of CYN destruction by UV-254 nm/H2O2 advanced oxidation process (AOP) was investigated by mass spectrometry. Various byproducts identified indicated three common reaction pathways: hydroxyl addition (+16 Da), alcoholic oxidation or dehydrogenation (-2 Da), and elimination of sulfate (-80 Da). The initiation of the degradation was observed at the hydroxymethyl uracil and tricyclic guanidine groups; uracil moiety cleavage/fragmentation and further ring-opening of the alkaloid were also noted at an extended reaction time or higher UV fluence. The degradation rates of CYN decreased and less byproducts (species) were detected using natural water matrices; however, CYN was effectively eliminated under extended UV irradiation. This study demonstrates the efficiency of CYN degradation and provides a better understanding of the mechanism of CYN degradation by hydroxyl radical, a reactive oxygen species that can be generated by most AOPs and is present in natural water environment.

  13. Solution processed nickel oxide anodes for organic photovoltaic devices

    SciTech Connect

    Mustafa, Bestoon; Griffin, Jonathan; Alsulami, Abdullah S.; Lidzey, David G.; Buckley, Alastair R.

    2014-02-10

    Nickel oxide thin films have been prepared from a nickel acetylacetonate (Ni(acac)) precursor for use in bulk heterojunction organic photovoltaic devices. The conversion of Ni(acac) to NiO{sub x} has been investigated. Oxygen plasma treatment of the NiO layer after annealing at 400 °C affords solar cell efficiencies of 5.2%. Photoelectron spectroscopy shows that high temperature annealing converts the Ni(acac) to a reduced form of nickel oxide. Additional oxygen plasma treatment further oxidizes the surface layers and deepens the NiO work function from 4.7 eV for the annealed film, to 5.0 eV allowing for efficient hole extraction at the organic interface.

  14. Slaughterhouse wastewater characteristics, treatment, and management in the meat processing industry: A review on trends and advances.

    PubMed

    Bustillo-Lecompte, Ciro Fernando; Mehrvar, Mehrab

    2015-09-15

    A thorough review of advancement in slaughterhouse wastewater (SWW) characteristics, treatment, and management in the meat processing industry is presented. This study also provides a general review of the environmental impacts, health effects, and regulatory frameworks relevant to the SWW management. A significant progress in high-rate anaerobic treatment, nutrient removal, advanced oxidation processes (AOPs), and the combination of biological treatment and AOPs for SWW treatment is highlighted. The treatment processes are described and few examples of their applications are given. Conversely, few advances are accounted in terms of waste minimization and water use reduction, reuse, and recycle in slaughterhouses, which may offer new alternatives for cost-effective waste management. An overview of the most frequently applied technologies and combined processes for organic and nutrient removal during the last decade is also summarized. Several types of individual and combined processes have been used for the SWW treatment. Nevertheless, the selection of a particular technology depends on the characteristics of the wastewater, the available technology, and the compliance with regulations. This review facilitates a better understanding of current difficulties that can be found during production and management of the SWW, including treatment and characteristics of the final effluent.

  15. Oxidation Ditches. Instructor's Guide. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Nelsen, David

    This instructor's guide contains materials needed for teaching a two-lesson unit on oxidation ditches. These materials include: (1) an overview of the two lessons; (2) lesson plans; (3) lecture outlines; (4) student worksheet (with answers); and (5) two copies of a final quiz (with and without answers). The first lesson: reviews the theory,…

  16. Process for fabricating doped zinc oxide microsphere gel

    DOEpatents

    Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

    1991-11-05

    Disclosed are a new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel. 4 figures.

  17. Process for fabricating doped zinc oxide microsphere gel

    DOEpatents

    Arnold, Jr., Wesley D.; Bond, Walter D.; Lauf, Robert J.

    1991-01-01

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

  18. LABORATORY MICROCOSM EXPERIMENTS OF OXIDATION PROCESSES AFTER STEAM INJECTION

    EPA Science Inventory

    Aggressive thermal methods such as steam injection or resistive heating are known to be effective for the recovery of many types of volatile and semivolatile compounds. It has been suggested that oxidation or other chemical reactions that occur at remediation temperatures can ai...

  19. Process for treating effluent from a supercritical water oxidation reactor

    SciTech Connect

    Barnes, C.M.; Shapiro, C.

    1995-12-31

    The present invention relates generally to a method for treating and recycling the effluent from a supercritical water oxidation reactor and more specifically to a method for treating and recycling the effluent by expanding the effluent without extensive cooling. Supercritical water oxidation is the oxidation of fuel, generally waste material, in a body of water under conditions above the thermodynamic critical point of water. The current state of the art in supercritical water oxidation plant effluent treatment is to cool the reactor effluent through heat exchangers or direct quench, separate the cooled liquid into a gas/vapor stream and a liquid/solid stream, expand the separated effluent, and perform additional purification on gaseous, liquid, brine and solid effluent. If acid gases are present, corrosion is likely to occur in the coolers. During expansion, part of the condensed water will revaporize. Vaporization can damage the valves due to cavitation and erosion. The present invention expands the effluent stream without condensing the stream. Radionuclides and suspended solids are more efficiently separated in the vapor phase. By preventing condensation, the acids are kept in the much less corrosive gaseous phase thereby limiting the damage to treatment equipment. The present invention also reduces the external energy consumption, by utilizing the expansion step to also cool the effluent.

  20. Identification of the sources of nitrous oxide produced by oxidative and reductive processes in Nitrosomonas europaea

    PubMed Central

    Ritchie, G. A. F.; Nicholas, D. J. D.

    1972-01-01

    1. Cells of Nitrosomonas europaea produced N2O during the oxidation of ammonia and hydroxylamine. 2. The end-product of ammonia oxidation, nitrite, was the predominant source of N2O in cells. 3. Cells also produced N2O, but not N2 gas, by the reduction of nitrite under anaerobic conditions. 4. Hydroxylamine was oxidized by cell-free extracts to yield nitrite and N2O aerobically, but to yield N2O and NO anaerobically. 5. Cell extracts reduced nitrite both aerobically and anaerobically to NO and N2O with hydroxylamine as an electron donor. 6. The relative amounts of NO and N2O produced during hydroxylamine oxidation and/or nitrite reduction are dependent on the type of artificial electron acceptor utilized. 7. Partially purified hydroxylamine oxidase retained nitrite reductase activity but cytochrome oxidase was absent. 8. There is a close association of hydroxylamine oxidase and nitrite reductase activities in purified preparations. PMID:5073730

  1. Pilot-scale UV/H2O2 advanced oxidation process for municipal reuse water: Assessing micropollutant degradation and estrogenic impacts on goldfish (Carassius auratus L.).

    PubMed

    Shu, Zengquan; Singh, Arvinder; Klamerth, Nikolaus; McPhedran, Kerry; Bolton, James R; Belosevic, Miodrag; Gamal El-Din, Mohamed

    2016-09-15

    Low concentrations (ng/L-μg/L) of emerging micropollutant contaminants in municipal wastewater treatment plant effluents affect the possibility to reuse these waters. Many of those micropollutants elicit endocrine disrupting effects in aquatic organisms resulting in an alteration of the endocrine system. A potential candidate for tertiary municipal wastewater treatment of these micropollutants is ultraviolet (UV)/hydrogen peroxide (H2O2) as an advanced oxidation process (AOP) which was currently applied to treat the secondary effluent of the Gold Bar Wastewater Treatment Plant (GBWWTP) in Edmonton, AB, Canada. A new approach is presented to predict the fluence-based degradation rate constants (kf') of environmentally occurring micropollutants including carbamazepine [(0.87-1.39) × 10(-3) cm(2)/mJ] and 2,4-Dichlorophenoxyacetic acid (2,4-D) [(0.60-0.91) × 10(-3) cm(2)/mJ for 2,4-D] in a medium pressure (MP) UV/H2O2 system based on a previous bench-scale investigation. Rather than using removal rates, this approach can be used to estimate the performance of the MP UV/H2O2 process for degrading trace contaminants of concern found in municipal wastewater. In addition to the ability to track contaminant removal/degradation, evaluation of the MP UV/H2O2 process was also accomplished by identifying critical ecotoxicological endpoints (i.e., estrogenicity) of the treated wastewater. Using quantitative PCR, mRNA levels of estrogen-responsive (ER) genes ERα1, ERα2, ERβ1, ERβ2 and NPR as well as two aromatase encoding genes (CYP19a and CYP19b) in goldfish (Carassius auratus L.) were measured during exposure to the GBWWTP effluent before and after MP UV/H2O2 treatment (a fluence of 1000 mJ/cm(2) and 20 mg/L of H2O2) in spring, summer and fall. Elevated expression of estrogen-responsive genes in goldfish exposed to UV/H2O2 treated effluent (a 7-day exposure) suggested that the UV/H2O2 process may induce acute estrogenic disruption to goldfish principally because

  2. Evaluation of pretreatment processes for supercritical water oxidation

    SciTech Connect

    Barnes, C.M.

    1994-01-01

    This report evaluates processes to chemically treat US Department of Energy wastes to remove organic halogens, phosphorus, and sulfur. Chemical equilibrium calculations, process simulations, and responses from developers and licensors form the basis for comparisons. Gas-phase catalytic hydrogenation processes, strong base and base catalyzed processes, high pressure hydrolysis, and other emerging or commercial dehalogenation processes (both liquid and mixed phase) were considered. Cost estimates for full-scale processes and demonstration testing are given. Based on the evaluation, testing of a hydrogenation process and a strong base process are recommended.

  3. Abatement of Polychoro-1,3-butadienes in Aqueous Solution by Ozone, UV Photolysis, and Advanced Oxidation Processes (O3/H2O2 and UV/H2O2).

    PubMed

    Lee, Minju; Merle, Tony; Rentsch, Daniel; Canonica, Silvio; von Gunten, Urs

    2017-01-03

    The abatement of 9 polychloro-1,3-butadienes (CBDs) in aqueous solution by ozone, UV-C(254 nm) photolysis, and the corresponding advanced oxidation processes (AOPs) (i.e., O3/H2O2 and UV/H2O2) was investigated. The following parameters were determined for 9 CBDs: second-order rate constants for the reactions of CBDs with ozone (kO3) (<0.1-7.9 × 10(3) M(-1) s(-1)) or with hydroxyl radicals (k(•)OH) (0.9 × 10(9) - 6.5 × 10(9) M(-1) s(-1)), photon fluence-based rate constants (k') (210-2730 m(2) einstein(-1)), and quantum yields (Φ) (0.03-0.95 mol einstein(-1)). During ozonation of CBDs in a natural groundwater, appreciable abatements (>50% at specific ozone doses of 0.5 gO3/gDOC to ∼100% at ≥1.0 gO3/gDOC) were achieved for tetra-CBDs followed by (Z)-1,1,2,3,4-penta-CBD and hexa-CBD. This is consistent with the magnitude of the determined kO3 and k(•)OH. The formation of bromate, a potentially carcinogenic ozonation byproduct, could be significantly reduced by addition of H2O2. For a typical UV disinfection dose (400 J/m(2)), various extents of phototransformations (10-90%) could be achieved. However, the efficient formation of photoisomers from CBDs with E/Z configuration must be taken into account because of their potential residual toxicity. Under UV-C(254 nm) photolysis conditions, no significant effect of H2O2 addition on CBDs abatement was observed due to an efficient direct phototransformation of CBDs.

  4. Oxidative processes during enzymatic hydrolysis of cod protein and their influence on antioxidant and immunomodulating ability.

    PubMed

    Halldorsdottir, Sigrun M; Sveinsdottir, Holmfridur; Freysdottir, Jona; Kristinsson, Hordur G

    2014-01-01

    Fish protein hydrolysates (FPH) have many desirable properties, however heating and shifts in pH can cause oxidation during enzymatic hydrolysis. The objective was to investigate oxidative processes during enzymatic hydrolysis of fish protein and the impact of oxidation on the antioxidant and immunomodulating ability of FPH. Protease P "Amano" 6 was used to hydrolyze cod protein in the presence and absence of pro-oxidants at pH 8 and 36°C to achieve 20% degree of hydrolysis. Results from thiobarbituric acid reactive substances (TBARS) and sensory analysis indicate that oxidation can develop rapidly during hydrolysis. A cellular antioxidant assay using a HepG2 cell model indicated a negative impact of oxidation products on antioxidant properties of the FPH while results obtained in chemical assays showed a negligible impact. Results from a dendritic cell model indicating that oxidation products may affect anti-inflammatory activity in the body. This study provides important information regarding bioactive FPH.

  5. Brain oxidation is an initial process in sleep induction.

    PubMed

    Ikeda, M; Ikeda-Sagara, M; Okada, T; Clement, P; Urade, Y; Nagai, T; Sugiyama, T; Yoshioka, T; Honda, K; Inoué, S

    2005-01-01

    CNS activity is generally coupled to the vigilance state, being primarily active during wakefulness and primarily inactive during deep sleep. During periods of high neuronal activity, a significant volume of oxygen is used to maintain neuronal membrane potentials, which subsequently produces cytotoxic reactive oxygen species (ROS). Glutathione, a major endogenous antioxidant, is an important factor protecting against ROS-mediated neuronal degeneration. Glutathione has also been proposed to be a sleep-promoting substance, yet the relationship between sleep and cerebral oxidation remains unclear. Here we report that i.c.v. infusion of the organic peroxide t-butyl-hydroperoxide at a concentration below that triggering neurodegeneration (0.1 micromol/100 microl/10 h) promotes sleep in rats. Also, microinjection (2 nmol, 2 microl) or microdialysis (100 microM, 20 min) of t-butyl-hydroperoxide into the preoptic/anterior hypothalamus (POAH) induces the release of the sleep-inducing neuromodulators, nitric oxide and adenosine, without causing neurodegeneration. Nitric oxide and adenosine release was inhibited by co-dialysis of the N-methyl-D-aspartate receptor antagonist, d(-)-2-amino-5-phosphonopentanoic acid (D-AP5; 1 mM), suggesting that glutamate-induced neuronal excitation mediates the peroxide-induced release of nitric oxide and adenosine. Indeed, Ca2+ release from mitochondria and delayed-onset Ca2+ influx via N-methyl-D-aspartate receptors was visualized during peroxide exposure using Ca2+ indicator proteins (YC-2.1 and mitochondrial-targeted Pericam) expressed in organotypic cultures of the POAH. In the in vitro models, t-butyl-hydroperoxide (50 microM) causes dendritic swelling followed by the intracellular Ca2+ mobilization, and D-AP5 (100 microM) or glutathione (500 microM) inhibited t-butyl-hydroperoxide-induced intracellular Ca2+ mobilization and protected POAH neurons from oxidative stress. These data suggest that low-level subcortical oxidation under the

  6. Scientific basis for process and catalyst design in the selective oxidation of methane to formaldehyde.

    PubMed

    Arena, Francesco; Parmaliana, Adolfo

    2003-12-01

    The mechanism and kinetics of the gas-phase selective oxidation of methane to formaldehyde (MPO) are revised in the general context of catalytic oxidations. In agreement with ab initio calculations of the energy barrier for the activation of methane on transition metal oxide complexes, a formal Langmuir-Hinshelwood kinetic model is proposed which accounts for the "steady-state" conditions and activity-selectivity pattern of MPO catalysts, providing an original support to process design and catalyst development.

  7. Applicability of nano zero valent iron (nZVI) in sono - Fenton process

    NASA Astrophysics Data System (ADS)

    Taha, M. R.; Ibrahim, A. H.; Amat, R. C.; Azhari, A. W.

    2014-04-01

    Fenton process is one of the advanced oxidation processes (AOPs) used to remove complex organic pollutants in wastewater. In this study, instead of iron sulfate (FeSO4), nano zero valent iron (nZVI) was used as a major source of ferrous iron (Fe2+). In order to enhance the process, ultrasound was utilized in this study. Results show that, with the aid of ultrasound, nZVI produced more Fe2+ compared to FeSO4 at pH 2. Furthermore, combination of higher intensity and longer sonication time in Fenton process acceleratde the chemical oxygen demand (COD) removal from palm oil mill effluent (POME). Through the process, 80% of COD content was removed within 2 hours instead of 24 hours of silent degradation.

  8. X-ray structure of the first `extremo-α-carbonic anhydrase', a dimeric enzyme from the thermophilic bacterium Sulfurihydrogenibium yellowstonense YO3AOP1.

    PubMed

    Di Fiore, Anna; Capasso, Clemente; De Luca, Viviana; Monti, Simona Maria; Carginale, Vincenzo; Supuran, Claudiu T; Scozzafava, Andrea; Pedone, Carlo; Rossi, Mosè; De Simone, Giuseppina

    2013-06-01

    SspCA, a novel `extremo-α-carbonic anhydrase' isolated from the thermophilic bacterium Sulfurihydrogenibium yellowstonense YO3AOP1, is an efficient catalyst for the hydration of CO2 and presents exceptional thermostability. Indeed, SspCA retains a high catalytic activity even after being heated to 343-373 K for several hours. Here, the crystallographic structure of this α-carbonic anhydrase (α-CA) is reported and the factors responsible for its function at high temperature are elucidated. In particular, the study suggests that increased structural compactness, together with an increased number of charged residues on the protein surface and a greater number of ionic networks, seem to be the key factors involved in the higher thermostability of this enzyme with respect to its mesophilic homologues. These findings are of extreme importance, since they provide a structural basis for the understanding of the mechanisms responsible for thermal stability in the α-CA family for the first time. The data obtained offer a tool that can be exploited to engineer α-CAs in order to obtain enzymes with enhanced thermostability for use in the harsh conditions of the CO2 capture and sequestration processes.

  9. Hierarchical zeolites and their catalytic performance in selective oxidative processes.

    PubMed

    Ojeda, Manuel; Grau-Atienza, Aida; Campos, Rafael; Romero, Antonio A; Serrano, Elena; Maria Marinas, Jose; García Martínez, Javier; Luque, Rafael

    2015-04-24

    Hierarchical ZSM-5 zeolites prepared using a simple alkali treatment and subsequent HCl washing are found to exhibit unprecedented catalytic activities in selective oxidation of benzyl alcohol under microwave irradiation. The metal-free zeolites promote the microwave-assisted oxidation of benzyl alcohol with hydrogen peroxide in yields ranging from 45-35 % after 5 min of reaction under mild reaction conditions as well as the epoxidation of cyclohexene to valuable products (40-60 % conversion). The hierarchically porous systems also exhibited an interesting catalytic activity in the dehydration of N,N-dimethylformamide (25-30 % conversion), representing the first example of transition-metal free catalysts in this reaction.

  10. Mussel-inspired approach to constructing robust cobalt-embedded N-doped carbon nanosheet toward enhanced sulphate radical-based oxidation

    NASA Astrophysics Data System (ADS)

    Zeng, Tao; Zhang, Haiyan; He, Zhiqiao; Chen, Jianmeng; Song, Shuang

    2016-09-01

    Heterogeneous sulphate radical based advanced oxidation processes (SR-AOPs) have lately been raised as a promising candidate for water treatment. Despite the progress made, either the stability or the performance of the current catalysts is still far from satisfactory for practical applications. Herein, using polydopamine-cobalt ion complex that inspired by mussel proteins as medium, we facilely fabricate a robust SR-AOPs catalyst with cobalt nanoparticles (NPs) embedded in nitrogen-doped reduced graphene oxide matrix (NRGO@Co). The NRGO scaffold with high porosity and surface area not only stabilizes the NPs but also greatly facilitates the accessibility and adsorption of substrates to the active sites. With the synergistic effect arising from the NRGO and Co NPs, the NRGO@Co hybrid catalyst exhibits enhanced catalytic activity for activation of peroxymonosulfate (PMS) to degrade organic pollutants in water. Furthermore, taking advantage of the favorable magnetic properties, the catalyst can be easily recycled and reused for at least 4 runs with negligible loss of activity. Coupled with systematic investigation in terms of influential factors, mineralization, and radicals identification, make the catalyst hold significant potential for application in remediation of organic pollutants in water.

  11. Mussel-inspired approach to constructing robust cobalt-embedded N-doped carbon nanosheet toward enhanced sulphate radical-based oxidation

    PubMed Central

    Zeng, Tao; Zhang, Haiyan; He, Zhiqiao; Chen, Jianmeng; Song, Shuang

    2016-01-01

    Heterogeneous sulphate radical based advanced oxidation processes (SR-AOPs) have lately been raised as a promising candidate for water treatment. Despite the progress made, either the stability or the performance of the current catalysts is still far from satisfactory for practical applications. Herein, using polydopamine-cobalt ion complex that inspired by mussel proteins as medium, we facilely fabricate a robust SR-AOPs catalyst with cobalt nanoparticles (NPs) embedded in nitrogen-doped reduced graphene oxide matrix (NRGO@Co). The NRGO scaffold with high porosity and surface area not only stabilizes the NPs but also greatly facilitates the accessibility and adsorption of substrates to the active sites. With the synergistic effect arising from the NRGO and Co NPs, the NRGO@Co hybrid catalyst exhibits enhanced catalytic activity for activation of peroxymonosulfate (PMS) to degrade organic pollutants in water. Furthermore, taking advantage of the favorable magnetic properties, the catalyst can be easily recycled and reused for at least 4 runs with negligible loss of activity. Coupled with systematic investigation in terms of influential factors, mineralization, and radicals identification, make the catalyst hold significant potential for application in remediation of organic pollutants in water. PMID:27616643

  12. Mathematical Modelling to Predict Oxidative Behaviour of Conjugated Linoleic Acid in the Food Processing Industry.

    PubMed

    Ojanguren, Aitziber; Ayo, Josune

    2013-06-20

    Industrial processes that apply high temperatures in the presence of oxygen may compromise the stability of conjugated linoleic acid (CLA) bioactive isomers. Statistical techniques are used in this study to model and predict, on a laboratory scale, the oxidative behaviour of oil with high CLA content, controlling the limiting factors of food processing. This modelling aims to estimate the impact of an industrial frying process (140 °C, 7 L/h air) on the oxidation of CLA oil for use as frying oil instead of sunflower oil. A factorial design was constructed within a temperature (80-200 °C) and air flow (7-20 L/h) range. Oil stability index (Rancimat method) was used as a measure of oxidation. Three-level full factorial design was used to obtain a quadratic model for CLA oil, enabling the oxidative behaviour to be predicted under predetermined process conditions (temperature and air flow). It is deduced that temperatures applied in food processes affect the oxidation of CLA to a greater extent than air flow. As a result, it is estimated that the oxidative stability of CLA oil is less resistant to industrial frying than sunflower oil. In conclusion, thanks to the mathematical model, a good choice of the appropriate industrial food process can be selected to avoid the oxidation of the bioactive isomers of CLA, ensuring its functionality in novel applications.

  13. Rational Concept for Reducing Growth Temperature in Vapor-Liquid-Solid Process of Metal Oxide Nanowires.

    PubMed

    Zhu, Zetao; Suzuki, Masaru; Nagashima, Kazuki; Yoshida, Hideto; Kanai, Masaki; Meng, Gang; Anzai, Hiroshi; Zhuge, Fuwei; He, Yong; Boudot, Mickaël; Takeda, Seiji; Yanagida, Takeshi

    2016-12-14

    Vapor-liquid-solid (VLS) growth process of single crystalline metal oxide nanowires has proven the excellent ability to tailor the nanostructures. However, the VLS process of metal oxides in general requires relatively high growth temperatures, which essentially limits the application range. Here we propose a rational concept to reduce the growth temperature in VLS growth process of various metal oxide nanowires. Molecular dynamics (MD) simulation theoretically predicts that it is possible to reduce the growth temperature in VLS process of metal oxide nanowires by precisely controlling the vapor flux. This concept is based on the temperature dependent "material flux window" that the appropriate vapor flux for VLS process of nanowire growth decreases with decreasing the growth temperature. Experimentally, we found the applicability of this concept for reducing the growth temperature of VLS processes for various metal oxides including MgO, SnO2, and ZnO. In addition, we show the successful applications of this concept to VLS nanowire growths of metal oxides onto tin-doped indium oxide (ITO) glass and polyimide (PI) substrates, which require relatively low growth temperatures.

  14. Ammonia-oxidizing bacteria and archaea in groundwater treatment and drinking water distribution systems.

    PubMed

    van der Wielen, Paul W J J; Voost, Stefan; van der Kooij, Dick

    2009-07-01

    The ammonia-oxidizing prokaryote (AOP) community in three groundwater treatment plants and connected distribution systems was analyzed by quantitative real-time PCR and sequence analysis targeting the amoA gene of ammonia-oxidizing bacteria (AOB) and archaea (AOA). Results demonstrated that AOB and AOA numbers increased during biological filtration of ammonia-rich anoxic groundwater, and AOP were responsible for ammonium removal during treatment. In one of the treatment trains at plant C, ammonia removal correlated significantly with AOA numbers but not with AOB numbers. Thus, AOA were responsible for ammonia removal in water treatment at one of the studied plants. Furthermore, an observed negative correlation between the dissolved organic carbon (DOC) concentration in the water and AOA numbers suggests that high DOC levels might reduce growth of AOA. AOP entered the distribution system in numbers ranging from 1.5 x 10(3) to 6.5 x 10(4) AOPs ml(-1). These numbers did not change during transport in the distribution system despite the absence of a disinfectant residual. Thus, inactive AOP biomass does not seem to be degraded by heterotrophic microorganisms in the distribution system. We conclude from our results that AOA can be commonly present in distribution systems and groundwater treatment, where they can be responsible for the removal of ammonia.

  15. Effect of Process Variables During the Head-End Treatment of Spent Oxide Fuel

    SciTech Connect

    K.J. Bateman; C.D. Morgan; J.F. Berg; D.J. Brough; P.J. Crane; D.G. Cummings; J.J. Giglio; M.W. Huntley; M.J. Rodriquez; J.D. Sommers; R.P. Lind; D.A. Sell

    2006-08-01

    The development of a head-end processing step for spent oxide fuel that applies to both aqueous and pyrometallurgical technologies is being performed by the Idaho National Laboratory, the Oak Ridge National Laboratory, and the Korean Atomic Energy Research Institute through a joint International Nuclear Energy Research Initiative. The processing step employs high temperatures and oxidative gases to promote the oxidation of UO2 to U3O8. Potential benefits of the head-end step include the removal or reduction of fission products as well as separation of the fuel from cladding. The effects of temperature, pressure, oxidative gas, and cladding have been studied with irradiated spent oxide fuel to determine the optimum conditions for process control. Experiments with temperatures ranging from 500oC to 1250oC have been performed on spent fuel using either air or oxygen gas for the oxidative reaction. Various flowrates and applications have been tested with the oxidative gases to discern the effects on the process. Tests have also been performed under vacuum conditions, following the oxidation cycle, at high temperatures to improve the removal of fission products. The effects of cladding on fission product removal have also been investigated with released fuel under vacuum and high temperature conditions. Results from these experiments will be presented as well as operating conditions based on particle size and decladding characteristics.

  16. Microbial Methane Oxidation Processes and Technologies for Mitigation of Landfill Gas Emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this paper is to review the present knowledge regarding the microbial methane oxidation in natural or engineered landfill environments with focus on process understanding, engineering experiences and modeling. This review includes seven sections. First, the methane oxidation is put in con...

  17. Processing, compatibility and oxidation of diboride-reinforced oxide matrix composites for ultrahigh-temperature applications

    SciTech Connect

    Abada, A.

    1990-01-01

    Promising results for the development of a ceramic/ceramic composite to be used for structural applications in the ultra high temperature range (1650 to 1850 C) were obtained for alumina reinforced with titanium or zirconium diboride coated with molybdenum disilicide. Calculations of the compatibility and stability of oxide matrices with the diborides in vacuum showed positive energies of formation, indicating suitability of reinforcement of alumina under vacuum conditions. Stability and chemical compatibility of the particulate and ternary composites in their as hot pressed states and following their vacuum and air oxidation treatment were characterized.

  18. High-Quality Solution-Processed Silicon Oxide Gate Dielectric Applied on Indium Oxide Based Thin-Film Transistors.

    PubMed

    Jaehnike, Felix; Pham, Duy Vu; Anselmann, Ralf; Bock, Claudia; Kunze, Ulrich

    2015-07-01

    A silicon oxide gate dielectric was synthesized by a facile sol-gel reaction and applied to solution-processed indium oxide based thin-film transistors (TFTs). The SiOx sol-gel was spin-coated on highly doped silicon substrates and converted to a dense dielectric film with a smooth surface at a maximum processing temperature of T = 350 °C. The synthesis was systematically improved, so that the solution-processed silicon oxide finally achieved comparable break downfield strength (7 MV/cm) and leakage current densities (<10 nA/cm(2) at 1 MV/cm) to thermally grown silicon dioxide (SiO2). The good quality of the dielectric layer was successfully proven in bottom-gate, bottom-contact metal oxide TFTs and compared to reference TFTs with thermally grown SiO2. Both transistor types have field-effect mobility values as high as 28 cm(2)/(Vs) with an on/off current ratio of 10(8), subthreshold swings of 0.30 and 0.37 V/dec, respectively, and a threshold voltage close to zero. The good device performance could be attributed to the smooth dielectric/semiconductor interface and low interface trap density. Thus, the sol-gel-derived SiO2 is a promising candidate for a high-quality dielectric layer on many substrates and high-performance large-area applications.

  19. TREATMENT OF PAHS AND PCBS USING SULFATE RADICAL-BASED OXIDATION PROCESSES

    EPA Science Inventory

    Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in aquatic systems pose serious threat to public health due to their toxicity and potential carcinogenicity [1]. Sulfate radical-based oxidation processes can be effectively used for degradation of these...

  20. DEMONSTRATION BULLETIN: CAV-OX ULTRAVIOLET OXIDATION PROCESS MAGNUM WATER TECHNOLOGY

    EPA Science Inventory

    The CAV-OX® technology (see Fig- ure 1) destroys organic contaminants, including chlorinated hy- drocarbons, in water. The process uses hydrogen peroxide, hy- drodynamic cavitation, and ultraviolet (UV) radiation to photolyze and oxidize organic compounds present in water at ...

  1. Thermally stable yttrium-scandium oxide high-k dielectrics deposited by a solution process

    NASA Astrophysics Data System (ADS)

    Hu, Wenbing; Frost, Bradley; Peterson, Rebecca L.

    2016-03-01

    We investigated the thermal stability of electrical properties in ternary alloy (Y x Sc1-x )2O3 high-k oxides as a function of yttrium fraction, x. The yttrium-scandium oxide dielectric films are deposited using a facile ink-based process. The oxides have a stoichiometry-dependent relative dielectric constant of 26.0 to 7.7 at 100 kHz, low leakage current density of 10-8 A·cm-2, high breakdown field of 4 MVṡcm-1, and interface trap density of 1012 cm-2·eV-1 with silicon. Compared with binary oxides, ternary alloys exhibit less frequency dispersion of the dielectric constant and a higher crystallization temperature. After crystallization is induced through a 900 °C anneal, ternary (Y0.6Sc0.4)2O3 films maintain their low leakage current and high breakdown field. In contrast, the electrical performance of the binary oxides significantly degrades following the same treatment. The solution-processed ternary oxide dielectrics demonstrated here may be used as high-k gate insulators in complementary metal-oxide semiconductor (CMOS) technologies, in novel electronic material systems and devices, and in printed, flexible thin film electronics, and as passivation layers for high power devices. These oxides may also be used as insulators in fabrication process flows that require a high thermal budget.

  2. Application of ozonation process in industrial wastewaters: textile, kraft E1 and whey effluents.

    PubMed

    Assalin, M R; Almeida, E S; Rosa, M A; Moraes, S G; Duran, N

    2004-08-01

    A large variety of organic and inorganic compounds can be found in wastewater from industrial processes. In this work, Advanced Oxidative Processes (AOPs) have been applied for the control of water pollution and the ozonation of different effluents was investigated. Wastewater from textile, kraft E1 and cheese manufacturing processes were chosen as examples of industrial effluents. The efficiency of substrate mineralization has been comparatively analyzed by the decrease in total organic carbon (TOC), color, and toxicity. The results revealed that the ozonation process can be a method for decolorization of effluent, but it is not effective for TOC reduction. The whey effluent was the most recalcitrant wastewater for ozone treatment which produced no TOC removal.

  3. Experimental Methodology for Determining Optimum Process Parameters for Production of Hydrous Metal Oxides by Internal Gelation

    SciTech Connect

    Collins, J.L.

    2005-10-28

    The objective of this report is to describe a simple but very useful experimental methodology that was used to determine optimum process parameters for preparing several hydrous metal-oxide gel spheres by the internal gelation process. The method is inexpensive and very effective in collection of key gel-forming data that are needed to prepare the hydrous metal-oxide microspheres of the best quality for a number of elements.

  4. Innovative Powder Processing of Oxide Dispersion Strengthened ODS Ferritic Stainless Steels

    SciTech Connect

    Rieken, Joel; Anderson, Iver; Kramer, Matthew

    2011-04-01

    An innovative gas atomization reaction synthesis technique was employed as a viable method to dramatically lower the processing cost for precursor oxide dispersion forming ferritic stainless steel powders (i.e., Fe-Cr-(Hf,Ti)-Y). During this rapid solidification process the atomized powders were enveloped by a nano-metric Cr-enriched metastable oxide film. Elevated temperature heat treatment was used to dissociate this metastable oxide phase through oxygen exchange reactions with Y-(Hf,Ti) enriched intermetallic compound precipitates. These solid state reactions resulted in the formation of highly stable nano-metric mixed oxide dispersoids (i.e., Y-Ti-O or Y-Hf-O) throughout the alloy microstructure. Subsequent high temperature (1200 C) heat treatments were used to elucidate the thermal stability of each nano-metric oxide dispersoid phase. Transmission electron microscopy coupled with X-ray diffraction was used to evaluate phase evolution within the alloy microstructure.

  5. The sulfide ore looping oxidation process: An alternative to current roasting and smelting practice

    NASA Astrophysics Data System (ADS)

    McHugh, Larry F.; Balliett, Robert; Mozolic, Jean A.

    2008-07-01

    This novel method utilizes the reactions of metal sulfides and metal oxides. It is applicable to single-metal systems such as Mo, Cu, Co, Ni, Fe, and Zn individual sulfides and to mixed sulfides such as chalcopyrite and Mo/Fe. In addition to primary ores, waste stream products such as spent catalysts can be effectively processed. The benchmark work done on MoS2/MoO3 resulted in an MoO2 product with less than 0.095 wt.% sulfur. Other sulfide concentrate materials showed similar results. In the first stage of the looping process, a highly concentrated SO2 off-gas stream is produced that could be directed to an acid plant or converted to liquid. The products from the first process step can be directed down line for further processing or can be used as is. In the second step of looping oxidation, the product is oxidized back to its fully oxidized state and is mainly looped back to drive the oxidation process in the first reaction. There are also several opportunities for energy recovery and conversion, making looping oxidation an energy-efficient process.

  6. A general route toward complete room temperature processing of printed and high performance oxide electronics.

    PubMed

    Baby, Tessy T; Garlapati, Suresh K; Dehm, Simone; Häming, Marc; Kruk, Robert; Hahn, Horst; Dasgupta, Subho

    2015-03-24

    Critical prerequisites for solution-processed/printed field-effect transistors (FETs) and logics are excellent electrical performance including high charge carrier mobility, reliability, high environmental stability and low/preferably room temperature processing. Oxide semiconductors can often fulfill all the above criteria, sometimes even with better promise than their organic counterparts, except for their high process temperature requirement. The need for high annealing/curing temperatures renders oxide FETs rather incompatible to inexpensive, flexible substrates, which are commonly used for high-throughput and roll-to-roll additive manufacturing techniques, such as printing. To overcome this serious limitation, here we demonstrate an alternative approach that enables completely room-temperature processing of printed oxide FETs with device mobility as large as 12.5 cm(2)/(V s). The key aspect of the present concept is a chemically controlled curing process of the printed nanoparticle ink that provides surprisingly dense thin films and excellent interparticle electrical contacts. In order to demonstrate the versatility of this approach, both n-type (In2O3) and p-type (Cu2O) oxide semiconductor nanoparticle dispersions are prepared to fabricate, inkjet printed and completely room temperature processed, all-oxide complementary metal oxide semiconductor (CMOS) invertors that can display significant signal gain (∼18) at a supply voltage of only 1.5 V.

  7. STEP wastewater treatment: a solar thermal electrochemical process for pollutant oxidation.

    PubMed

    Wang, Baohui; Wu, Hongjun; Zhang, Guoxue; Licht, Stuart

    2012-10-01

    A solar thermal electrochemical production (STEP) pathway was established to utilize solar energy to drive useful chemical processes. In this paper, we use experimental chemistry for efficient STEP wastewater treatment, and suggest a theory based on the decreasing stability of organic pollutants (hydrocarbon oxidation potentials) with increasing temperature. Exemplified by the solar thermal electrochemical oxidation of phenol, the fundamental model and experimental system components of this process outline a general method for the oxidation of environmentally stable organic pollutants into carbon dioxide, which is easily removed. Using thermodynamic calculations we show a sharply decreasing phenol oxidation potential with increasing temperature. The experimental results demonstrate that this increased temperature can be supplied by solar thermal heating. In combination this drives electrochemical phenol removal with enhanced oxidation efficiency through (i) a thermodynamically driven decrease in the energy needed to fuel the process and (ii) improved kinetics to sustain high rates of phenol oxidation at low electrochemical overpotential. The STEP wastewater treatment process is synergistic in that it is performed with higher efficiency than either electrochemical or photovoltaic conversion process acting alone. STEP is a green, efficient, safe, and sustainable process for organic wastewater treatment driven solely by solar energy.

  8. Formation process of in situ oxide coatings with high porosity using one-step plasma electrolytic oxidation

    NASA Astrophysics Data System (ADS)

    Yu, Xiwen; Chen, Li; Qin, Honglei; Wu, Mingyue; Yan, Zongcheng

    2016-03-01

    Porous oxide films prepared via plasma electrolytic oxidation are ideal in situ catalysts. However, such films have low porosity. To overcome this limitation, we proposed a promising approach that controls discharge events. The treatments were performed in two kinds of alkaline-silicate solutions namely KOH-enriched solution and Na2SiO3-enriched solution. The coatings prepared in the former electrolyte exhibited superior growth behaviors and catalytic structures. Due to the strong corrosive of KOH-enriched electrolyte, the growth of the film was suppressed, and the sparks were maintained small and evenly distributed throughout the process. Such layers showed high porosity and were evenly covered by nanoparticles. The coating porosity increased with increasing time, and the film treated for 60 min exhibited a high porosity of 33.3 ± 1.7%. Moreover, an oxide film with an outer dendritic and inner porous structure was formed within 120 min. The energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy characterizations indicated that the coatings were mainly composed of aluminum oxide and that the doped iron oxide was enriched on the top surface of the coating. Finally, the formation mechanisms of the coating and nanoparticles were discussed with consideration of the dynamic equilibrium theory.

  9. Dissolution of Neptunium and Plutonium Oxides Using a Catalyzed Electrolytic Process

    SciTech Connect

    Hylton, TD

    2004-10-25

    This report discusses the scoping study performed to evaluate the use of a catalyzed electrolytic process for dissolving {sup 237}Np oxide targets that had been irradiated to produce {sup 238}Pu oxide. Historically, these compounds have been difficult to dissolve, and complete dissolution was obtained only by adding hydrofluoric acid to the nitric acid solvent. The presence of fluoride in the mixture is undesired because the fluoride ions are corrosive to tank and piping systems and the fluoride ions cause interferences in the spectrophotometric analyses. The goal is to find a dissolution method that will eliminate these issues and that can be incorporated into a processing system to support the domestic production and purification of {sup 238}Pu. This study evaluated the potential of cerium(IV) ions, a strong oxidant, to attack and dissolve the oxide compounds. In the dissolution process, the cerium(IV) ions are reduced to cerium(III) ions, which are not oxidants. Therefore, an electrolytic process was incorporated to continuously convert cerium(III) ions back to cerium(IV) ions so that they can dissolve more of the oxide compounds. This study showed that the neptunium and plutonium oxides were successfully dissolved and that more development work should be performed to optimize the procedure.

  10. Analysis of nitrous oxide emissions from conventional combustion processes

    SciTech Connect

    Danihelka, P.; Juchelkova, D.; Kula, P.

    1995-12-31

    Since 1980 it has been recognized that N{sub 2}O plays important roles in stratospheric ozone depletion and global climate change. Even if the emission of N{sub 2}O is considered to be a potential environmental problem, most countries, Czech Republic included, has no legislative limits for N{sub 2}O emissions. VSB-Technical University, in cooperation with the Academy of Sciences of the Czech Republic and TU Vienna (Austria), started research on N{sub 2}O emissions from stationary industrial sources. Non-continuous sampling technique which prevents positive errors caused by the N{sub 2}O formation in the container has been developed and the GC-ECD analytical technique used for N{sub 2}O detection. Sulfur dioxide, carbon dioxide and moisture should be completely removed from the sample. For typical stationary sources in the Czech Republic, the concentrations of nitrous oxide have been measured.

  11. Processing, Compatibility and Oxidation of Diboride - Oxide Matrix Composites for Ultrahigh-Temperature Applications.

    NASA Astrophysics Data System (ADS)

    Abada, Ahmed

    1990-01-01

    Promising results for the development of a ceramic/ceramic composite to be used for structural applications in the ultra high temperature range (1650-1850^ circC) have been obtained for alumina reinforced with titanium or zirconium diboribe coated with molybdenum disilicide. Prior to this achievement, several theoretical and experimental studies of particulate composites with (TiB_2 or ZrB_2) imbedded in (ZrO_2, Y_2 O_3 or Al_2 O_3) were conducted. Calculations of the compatibility and stability of oxide matrices with the diborides in vacuum showed positive energies of formation, indicating suitability of reinforcement of alumina under vacuum conditions. Also, since the sublimation of vapor species at ultra high temperatures is very critical to the stability of substances still existing in their condensed states, a detailed thermodynamic analysis of the metal -oxygen systems, was carried out using elemental data of the TiB_2, ZrB_2 , ZrO_2, Y_2 O_3, Al_2 O_3, MoSi_2 and their combinations (TiB_2 or ZrB_2)/(ZrO_2 , Y_2O_3 or Al_2O_3) for comparison, at 1650, 1850 and 2050^ circC. A comparison of the combination TiB _2 and ZrB_2 in MoSi_2/(Al_2O _3 or ZrO_2) at 1650^circC was also made. A stability analysis using equilibrium oxygen partial pressures for the TiB_2 and ZrB_2 decomposition at 1650, 1850 and 2050^ circC was carried out. A detailed characterization of the powders used for the oxide matrices, the diborides and the molybdenum disilicide are presented. The effects of the powder characteristics and the vacuum hot pressing parameters on the densification of the composites are discussed. Stability and chemical compatibility of the particulate and ternary composites in their as hot pressed states and following their vacuum and air oxidation treatments were characterized. Interdiffusion of elemental species across diboride/disilicide and oxide/disilicide interfaces was studies by EDS dot mapping. It is proposed that the growth of the Mo _5Si_3 is interface

  12. Purification of 238Pu Oxide using the Pu Oxalate Process

    SciTech Connect

    Mew, D A; Krikorian, O H; Dodson, K E; Schmitz, J A

    2001-11-28

    The Pu oxalate process is used to remove {sup 234}U from aged {sup 238}Pu-enriched PuO{sub 2} ({sup 234}U grows into the PuO{sub 2} material with time from a-decay of {sup 238}Pu). The Pu oxalate process was first used on a mixture of weapons grade PuO{sub 2} with UO{sub 2} to work out the processing parameters. It was then applied to aged {sup 238}Pu-enriched PuO{sub 2} ({sup 238}PuO{sub 2}). The {sup 234}U content of the {sup 238}PuO{sub 2} was reduced from 13.2 wt% to 0.0254 wt%, and the Pu recovery yield was 78.5%. The process is complex and is complicated by radiolysis problems when working with {sup 238}Pu. Details of the experiments are described.

  13. Iron Oxide Films Prepared by Rapid Thermal Processing for Solar Energy Conversion

    NASA Astrophysics Data System (ADS)

    Wickman, B.; Bastos Fanta, A.; Burrows, A.; Hellman, A.; Wagner, J. B.; Iandolo, B.

    2017-01-01

    Hematite is a promising and extensively investigated material for various photoelectrochemical (PEC) processes for energy conversion and storage, in particular for oxidation reactions. Thermal treatments during synthesis of hematite are found to affect the performance of hematite electrodes considerably. Herein, we present hematite thin films fabricated via one-step oxidation of Fe by rapid thermal processing (RTP). In particular, we investigate the effect of oxidation temperature on the PEC properties of hematite. Films prepared at 750 °C show the highest activity towards water oxidation. These films show the largest average grain size and the highest charge carrier density, as determined from electron microscopy and impedance spectroscopy analysis. We believe that the fast processing enabled by RTP makes this technique a preferred method for investigation of novel materials and architectures, potentially also on nanostructured electrodes, where retaining high surface area is crucial to maximize performance.

  14. Iron Oxide Films Prepared by Rapid Thermal Processing for Solar Energy Conversion

    PubMed Central

    Wickman, B.; Bastos Fanta, A.; Burrows, A.; Hellman, A.; Wagner, J. B.; Iandolo, B.

    2017-01-01

    Hematite is a promising and extensively investigated material for various photoelectrochemical (PEC) processes for energy conversion and storage, in particular for oxidation reactions. Thermal treatments during synthesis of hematite are found to affect the performance of hematite electrodes considerably. Herein, we present hematite thin films fabricated via one-step oxidation of Fe by rapid thermal processing (RTP). In particular, we investigate the effect of oxidation temperature on the PEC properties of hematite. Films prepared at 750 °C show the highest activity towards water oxidation. These films show the largest average grain size and the highest charge carrier density, as determined from electron microscopy and impedance spectroscopy analysis. We believe that the fast processing enabled by RTP makes this technique a preferred method for investigation of novel materials and architectures, potentially also on nanostructured electrodes, where retaining high surface area is crucial to maximize performance. PMID:28091573

  15. Chemical oxidation of sulfadiazine by the Fenton process: kinetics, pathways, toxicity evaluation.

    PubMed

    Yang, Ji-Feng; Zhou, Shi-Biao; Xiao, An-Guo; Li, Wen-Jun; Ying, Guang-Guo

    2014-01-01

    This paper investigated sulfadiazine oxidation by the Fenton process under various reaction conditions. The reaction conditions tested in the experiments included the initial pH value of reaction solutions, and the dosages of ferrous ions and hydrogen peroxide. Under the reaction conditions with pH 3, 0.25 mM of ferrous ion and 2 mM of hydrogen peroxide, a removal efficiency of nearly 100% was achieved for sulfadiazine. A series of intermediate products including 4-OH-sulfadiazine/or 5-OH-sulfadiazine, 2-aminopyrimidine, sulfanilamide, formic acid, and oxalic acid were identified. Based on these products, the possible oxidation pathway of sulfadiazine by Fenton's reagent was proposed. The toxicity evaluation of reaction solutions showed increased antimicrobial effects following the Fenton oxidation process. The results from this study suggest that the Fenton oxidation process could remove sulfadiazine, but also increase solution toxicity due to the presence of more toxic products.

  16. Removal of pharmaceuticals from water by homo/heterogonous Fenton-type processes - A review.

    PubMed

    Mirzaei, Amir; Chen, Zhi; Haghighat, Fariborz; Yerushalmi, Laleh

    2017-05-01

    The presence of emerging contaminants such as pharmaceuticals in natural waters has raised increasing concern due to their frequent appearance and persistence in the aquatic ecosystem and the threat to health and safety of aquatic life, even at trace concentrations. Conventional water treatment processes are known to be generally inadequate for the elimination of these persistent contaminants. Therefore, the use of advanced oxidation processes (AOPs) which are able to efficiently oxidize organic pollutants has attracted a great amount of attention. The main limitation of AOPs lies in their high operating costs associated with the consumption of energy and chemicals. Fenton-based processes, which utilize nontoxic and common reagents and potentially can exploit solar energy, will considerably reduce the removal cost of recalcitrant contaminants. The disadvantages of homogeneous Fenton processes, such as the generation of high amounts of iron-containing sludge and limited operational range of pH, have prompted much attention to the use of heterogeneous Fenton processes. In this review, the impacts of some controlling parameters including the H2O2 and catalyst dosage, solution pH, initial contaminants concentrations, temperature, type of catalyst, intensity of irradiation, reaction time and feeding mode on the removal efficiencies of hetero/homogeneous Fenton processes are discussed. In addition, the combination of Fenton-type processes with biological systems as the pre/post treatment stages in pilot-scale operations is considered. The reported experimental results obtained by using Fenton and photo-Fenton processes for the elimination of pharmaceutical contaminants are also compiled and evaluated.

  17. Electrochemical reaction and oxidation of lecithin under pulsed electric fields (PEF) processing.

    PubMed

    Zhao, Wei; Yang, Ruijin; Liang, Qi; Zhang, Wenbin; Hua, Xiao; Tang, Yali

    2012-12-12

    Pulsed electric fields (PEF) processing is a promising nonthermal food preservation technology, which is ongoing from laboratory and pilot plant scale levels to the industrial level. Currently, greater attention has been paid to side effects occurring during PEF treatment and the influences on food qualities and food components. The present study investigated the electrochemical reaction and oxidation of lecithin under PEF processing. Results showed that electrochemical reaction of NaCl solutions at different pH values occurred during PEF processing. Active chlorine, reactive oxygen, and free radicals were detected, which were related to the PEF parameters and pH values of the solution. Lecithin extracted from yolk was further selected to investigate the oxidation of food lipids under PEF processing, confirming the occurrence of oxidation of lecithin under PEF treatment. The oxidative agents induced by PEF might be responsible for the oxidation of extracted yolk lecithin. Moreover, this study found that vitamin C as a natural antioxidant could effectively quench free radicals and inhibit the oxidation of lipid in NaCl and lecithin solutions as model systems under PEF processing, representing a way to minimize the impact of PEF treatment on food qualities.

  18. Direct Growth of Crystalline Tungsten Oxide Nanorod Arrays by a Hydrothermal Process and Their Electrochromic Properties

    NASA Astrophysics Data System (ADS)

    Lu, Chih-Hao; Hon, Min Hsiung; Leu, Ing-Chi

    2016-12-01

    Transparent crystalline tungsten oxide nanorod arrays for use as an electrochromic layer have been directly prepared on fluorine-doped tin oxide-coated glass via a facile tungsten film-assisted hydrothermal process using aqueous tungsten hexachloride solution. X-ray diffraction analysis and field-emission scanning electron microscopy were used to characterize the phase and morphology of the grown nanostructures. Arrays of tungsten oxide nanorods with diameter of ˜22 nm and length of ˜240 nm were obtained at 200°C after 8 h of hydrothermal reaction. We propose a growth mechanism for the deposition of the monoclinic tungsten oxide phase in the hydrothermal environment. The tungsten film was first oxidized to tungsten oxide to provide seed sites for crystal growth and address the poor connection between the growing tungsten oxide and substrate. Aligned tungsten oxide nanorod arrays can be grown by a W thin film-assisted heterogeneous nucleation process with NaCl as a structure-directing agent. The fabricated electrochromic device demonstrated optical modulation (coloration/bleaching) at 632.8 nm of ˜41.2% after applying a low voltage of 0.1 V for 10 s, indicating the potential of such nanorod array films for use in energy-saving smart windows.

  19. Direct Growth of Crystalline Tungsten Oxide Nanorod Arrays by a Hydrothermal Process and Their Electrochromic Properties

    NASA Astrophysics Data System (ADS)

    Lu, Chih-Hao; Hon, Min Hsiung; Leu, Ing-Chi

    2017-04-01

    Transparent crystalline tungsten oxide nanorod arrays for use as an electrochromic layer have been directly prepared on fluorine-doped tin oxide-coated glass via a facile tungsten film-assisted hydrothermal process using aqueous tungsten hexachloride solution. X-ray diffraction analysis and field-emission scanning electron microscopy were used to characterize the phase and morphology of the grown nanostructures. Arrays of tungsten oxide nanorods with diameter of ˜22 nm and length of ˜240 nm were obtained at 200°C after 8 h of hydrothermal reaction. We propose a growth mechanism for the deposition of the monoclinic tungsten oxide phase in the hydrothermal environment. The tungsten film was first oxidized to tungsten oxide to provide seed sites for crystal growth and address the poor connection between the growing tungsten oxide and substrate. Aligned tungsten oxide nanorod arrays can be grown by a W thin film-assisted heterogeneous nucleation process with NaCl as a structure-directing agent. The fabricated electrochromic device demonstrated optical modulation (coloration/bleaching) at 632.8 nm of ˜41.2% after applying a low voltage of 0.1 V for 10 s, indicating the potential of such nanorod array films for use in energy-saving smart windows.

  20. Trimethoprim: kinetic and mechanistic considerations in photochemical environmental fate and AOP treatment.

    PubMed

    Luo, Xingzhang; Zheng, Zheng; Greaves, John; Cooper, William J; Song, Weihua

    2012-03-15

    Trimethoprim (TMP), a bacteriostatic antibiotic, has recently been detected in wastewater and surface waters. In this study the sunlight mediated photochemical fate, and treatment using advanced oxidation and reduction (free radical) processes, have been investigated with respect to their effect on TMP. Photochemical fate, in the presence of humic acid, and advanced oxidation treatment both involve the hydroxyl radical (OH) as one of the reactive species of interest. Another reactive oxygen species, singlet oxygen (1O2), may also be important in the photochemical fate of TMP. The bimolecular reaction rate constants of TMP with 1O2 and OH were evaluated to be (3.2±0.2)×10(6) M(-1) s(-1) and 8.66×10(9) M(-1) s(-1), respectively. The reaction kinetics for the sub-structural moieties of TMP, 1,2,3-trimethoxybenzene (TMBz) and 2,4-diaminoprimidine (DAP), was evaluated to facilitate an understanding of the loss mechanisms. For TMBz and DAP the reaction rate constants with 1O2 were <1.0×10(4) and (3.0±0.1)×10(6) M(-1) s(-1), while with OH they were 8.12×10(9) and 1.64×10(9) M(-1) s(-1), respectively. The data suggests that the 1O2 attacks the DAP and the OH radical attacks the TMBz moiety. However, for TMP, 1O2 and OH reactions accounted for only ∼19% and ∼6%, of its total photodegradation, respectively. Therefore, the reaction of TMP with excited state natural organic matter is postulated as a significant degradation pathway for the loss of TMP in sunlit waters containing natural organic matter. There was no effect of pH on the direct or indirect photolysis of TMP. To complete the study for reductive treatment processes, the solvated electron reaction rates for the destruction of TMP, TMBz and DAP were also evaluated. The absolute bimolecular reaction rates obtained were, (13.6±0.01)×10(9), (6.36±0.11)×10(7) and (10.1±0.01)×10(9) M(-1) s(-1), respectively.

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

    PubMed

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

    2014-01-01

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

  2. Removal of recalcitrant organic matter content in wastewater by means of AOPs aiming industrial water reuse.

    PubMed

    Souza, Bianca M; Souza, Bruno S; Guimarães, Tarsila M; Ribeiro, Thiago F S; Cerqueira, Ana C; Sant'Anna, Geraldo L; Dezotti, Márcia

    2016-11-01

    This paper comes out from the need to provide an improvement in the current oil refinery wastewater treatment plant (WWTP) aiming to generate water for reuse. The wastewater was pretreated and collected in the WWTP after the biological treatment unit (bio-disks) followed by sand filtration. Ozonation (ozone concentration from 3.0-60 mgO3 L(-1)), UV (power lamp from 15 to 95 W), H2O2 (carbon:H2O2 molar ratio of 1:1, 1:2, and 1:4), and two advanced oxidation processes (UV/O3 and UV/H2O2) were investigated aiming to reduce the wastewater organic matter and generate water with suitable characteristics for the reverse osmosis operation and subsequent industrial reuse. Even after the biological and filtration treatments, the oil refinery wastewater still presented an appreciable amount of recalcitrant organic matter (TOC of 12-19 mgC L(-1)) and silt density index (SDI) higher than 4, which is considered high for subsequent reverse osmosis due to membrane fouling risks. Experiments using non combined processes (O3, H2O2, and UV only) showed a low degree of mineralization after 60 min of reaction, although the pretreatment with ozone had promoted the oxidation of aromatic compounds originally found in the real matrix, which suggests the formation of recalcitrant compounds. When the combined processes were applied, a considerable increase in the TOC removal was observed (max of 95 % for UV/O3 process, 55 W, 60 mgO3 L(-1)), likely due the presence of higher amounts of reactive species, specially hydroxyl radicals, confirming the important role of these species on the photochemical degradation of the wastewater compounds. A zero-order kinetic model was fitted to the experimental data and the rate constant values (k, mgC L(-1) h(-1)) ranged from 4.8 < k UV/O3 < 11 ([O3]0 = 30-60 mg L(-1)), and 8.6 < k UV/H2O2 < 11 (C:H2O2 from 1:1 to 1:4). The minimum and maximum electrical energy per order (E EO) required for 60 min of treatment were calculated as 5

  3. Ceruloplasmin copper induces oxidant damage by a redox process utilizing cell-derived superoxide as reductant

    NASA Technical Reports Server (NTRS)

    Mukhopadhyay, C. K.; Fox, P. L.

    1998-01-01

    Oxidative damage by transition metals bound to proteins may be an important pathogenic mechanism. Ceruloplasmin (Cp) is a Cu-containing plasma protein thought to be involved in oxidative modification of lipoproteins. We have previously shown that Cp increased cell-mediated low-density lipoprotein (LDL) oxidation by a process requiring cell-derived superoxide, but the underlying chemical mechanism(s) is (are) unknown. We now show that superoxide reduction of Cp Cu is a critical reaction in cellular LDL oxidation. By bathocuproine disulfonate (BCS) binding and by superoxide utilization, we showed that exogenous superoxide reduces a single Cp Cu atom, the same Cu required for LDL oxidation. The Cu atom remained bound to Cp during the redox cycle. Three avenues of evidence showed that vascular cells reduce Cp Cu by a superoxide-dependent process. The 2-fold higher rate of Cp Cu reduction by smooth muscle cells (SMC) compared to endothelial cells (EC) was consistent with their relative rates of superoxide release. Furthermore, Cp Cu reduction by cells was blocked by Cu,Zn superoxide dismutase (SOD1). Finally, the level of superoxide produced by EC and SMC was sufficient to cause the amount of Cu reduction observed. An important role of Cp Cu reduction in LDL oxidation was suggested by results showing that SOD1 inhibited Cp Cu reduction and LDL oxidation by SMC with equal potency, while tumor necrosis factor-alpha stimulated both processes. In summary, these results show that superoxide is a critical cellular reductant of divalent transition metals involved in oxidation, and that protein-bound Cu is a substrate for this reaction. The role of these mechanisms in oxidative processes in vivo has yet to be defined.

  4. The 1% and 1 cm perspective in deriving and validating AOP data products

    NASA Astrophysics Data System (ADS)

    Hooker, S. B.; Morrow, J. H.; Matsuoka, A.

    2012-07-01

    A next-generation in-water profiler designed to measure the apparent optical properties (AOPs) of seawater was developed and validated across a wide dynamic range of in-water properties. The new free-falling instrument, the Compact-Optical Profiling System (C-OPS), was based on a cluster of 19 state-of-the-art microradiometers spanning 320-780 nm and a new kite-shaped backplane design. The kite-shaped backplane includes tunable ballast, a hydrobaric buoyancy chamber, plus pitch and roll adjustments, to provide unprecedented stability and vertical resolution in near-surface waters. A unique data set was collected as part of the development activity and the first major field campaign that used the new instrument, the Malina expedition to the Beaufort Sea in the vicinity of the Mackenzie River outflow. The data were of sufficient resolution and quality to show that errors - more correctly, uncertainties - in the execution of data sampling protocols were measurable at the 1% and 1 cm level with C-OPS. A sensitivity analysis as a function of three water types established by the peak in the remote sensing reflectance spectrum, Rrs(λ), revealed which water types and which parts of the spectrum were the most sensitive to data acquisition uncertainties. Shallow riverine waters were the most sensitive water type, and the ultraviolet and near-infrared were the most sensitive parts of the spectrum. The sensitivity analysis also showed how the use of data products based on band ratios significantly mitigated the influence of data acquisition uncertainties. The unprecedented vertical resolution provided high quality data products at the spectral end members, which subsequently supported an alternative classification capability based on the spectral diffuse attenuation coefficient, Kd(λ). The Kd(320) and Kd(780) data showed how complex coastal systems can be distinguished two-dimensionally and how near-ice water masses are different from the open ocean. Finally, an algorithm

  5. Single-photon imaging in complementary metal oxide semiconductor processes

    PubMed Central

    Charbon, E.

    2014-01-01

    This paper describes the basics of single-photon counting in complementary metal oxide semiconductors, through single-photon avalanche diodes (SPADs), and the making of miniaturized pixels with photon-counting capability based on SPADs. Some applications, which may take advantage of SPAD image sensors, are outlined, such as fluorescence-based microscopy, three-dimensional time-of-flight imaging and biomedical imaging, to name just a few. The paper focuses on architectures that are best suited to those applications and the trade-offs they generate. In this context, architectures are described that efficiently collect the output of single pixels when designed in large arrays. Off-chip readout circuit requirements are described for a variety of applications in physics, medicine and the life sciences. Owing to the dynamic nature of SPADs, designs featuring a large number of SPADs require careful analysis of the target application for an optimal use of silicon real estate and of limited readout bandwidth. The paper also describes the main trade-offs involved in architecting such chips and the solutions adopted with focus on scalability and miniaturization. PMID:24567470

  6. Chemical processes for the extreme enrichment of tellurium into marine ferromanganese oxides

    NASA Astrophysics Data System (ADS)

    Kashiwabara, Teruhiko; Oishi, Yasuko; Sakaguchi, Aya; Sugiyama, Toshiki; Usui, Akira; Takahashi, Yoshio

    2014-04-01

    Tellurium, an element of growing economic importance, is extremely enriched in marine ferromanganese oxides. We investigated the mechanism of this enrichment using a combination of spectroscopic analysis and adsorption/coprecipitation experiments. X-ray Absorption Near-Edge Structure (XANES) analysis showed that in adsorption/coprecipitation systems, Te(IV) was oxidized on δ-MnO2 and not oxidized on ferrihydrite. Extended X-ray Absorption Fine Structure (EXAFS) analysis showed that both Te(IV) and Te(VI) were adsorbed on the surface of δ-MnO2 and ferrihydrite via formation of inner-sphere complexes. In addition, Te(VI) can be structurally incorporated into the linkage of Fe octahedra through a coprecipitation process because of its molecular geometry that is similar to the Fe octahedron. The largest distribution coefficient obtained in the adsorption/coprecipitation experiments was for the Te(VI)/ferrihydrite coprecipitation system, and it was comparable to those calculated from the distribution between natural ferromanganese oxides and seawater. Our XAFS and micro-focused X-ray fluorescence (μ-XRF) mapping of natural ferromanganese oxides showed that Te was structurally incorporated as Te(VI) in Fe (oxyhydr)oxide phases. We conclude that the main process for the enrichment of Te in ferromanganese oxides is structural incorporation of Te(VI) into Fe (oxyhydr)oxide phases through coprecipitation. This mechanism can explain the unique degree of enrichment of Te compared with other oxyanions, which are mainly enriched via adsorption on the surface of the solid structures. In particular, the great contrast in the distributions of Te and Se is caused by their oxidized species: (i) the similar geometry of the Te(VI) molecule to Fe octahedron, and (ii) quite soluble nature of Se(VI). Coexisting Mn oxide phases may promote structural incorporation of Te(VI) by oxidation of Te(IV), although the surface oxidation itself may not work as the critical enrichment process as

  7. Zinc-oxide-based sorbents and processes for preparing and using same

    DOEpatents

    Gangwal, Santosh Kumar; Turk, Brian Scott; Gupta, Raghubir Prasael

    2010-03-23

    Zinc oxide-based sorbents, and processes for preparing and using them are provided. The sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents comprise an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, comprising a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

  8. Zinc oxide-based sorbents and processes for preparing and using same

    DOEpatents

    Gangwal, Santosh Kumar; Turk, Brian Scott; Gupta, Raghubir Prasad

    2005-10-04

    Zinc oxide-based sorbents, and processes for preparing and using them are provided, wherein the sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents contain an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2 O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, containing a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

  9. Protein oxidation during frozen storage and subsequent processing of different beef muscles.

    PubMed

    Utrera, Mariana; Parra, Vita; Estévez, Mario

    2014-02-01

    This study examined the relationship between protein and lipid oxidation and the impairment of the water holding capacity (WHC), redness and instrumental hardness occurring during 20 weeks of frozen storage (-18 °C) and subsequent processing (cooking, chilled storage) of psoas major, quadriceps femoris and longissimus dorsi beef patties. Patties were analyzed at sampling times upon thawing (weeks 0, 4, 8, 12 and 20) for lipid (TBARS, hexanal) and protein oxidation products (α-aminoadipic and γ-glutamic semialdehydes, α-aminoadipic acid, Schiff bases). A significant impact of frozen storage on protein oxidation was found, which occurred concomitantly with a loss of WHC, redness and significant changes in the hardness of cooked patties. Heme-iron, endogenous antioxidant enzymes and to a lower extent, fatty acid composition, played a role in the oxidative stability of patties. Plausible mechanisms by which particular protein oxidation changes may lead to loss of WHC and impaired quality traits were discussed.

  10. A review on the recent developments of solution processes for oxide thin film transistors

    NASA Astrophysics Data System (ADS)

    Du Ahn, Byung; Jeon, Hye-Ji; Sheng, Jiazhen; Park, Jozeph; Park, Jin-Seong

    2015-06-01

    This review article introduces the recent advances in the development of oxide semiconductor materials based on solution processes and their potential applications. In the early stage, thin film transistors based on oxide semiconductors fabricated by solution processes used to face critical problems such as high annealing temperatures (>400 °C) required to obtain reasonable film quality, and the relatively low field effect mobility (<5 cm2 V-1 s-1) compared to devices fabricated by conventional vacuum-based techniques. In order to overcome such hurdles, the proper selection of high mobility amorphous oxide semiconductor materials is addressed first. The latter involves the combination of high mobility compounds and multilayered active stacks. Ensuing overviews are provided on the selection of optimum precursors and alternative annealing methods that enable the growth of high quality films at relatively low process temperatures (<200 °C). Reasonably high field effect mobility values (~10 cm2 V-1 s-1) could thus be obtained by optimizing the above process parameters. Finally, potential applications of solution processed oxide semiconductor devices are summarized, involving, for instance, flexible displays, biosensors, and non-volatile memory devices. As such, further innovations in the solution process methods of oxide semiconductor devices are anticipated to allow the realization of cost effective, large area electronics in the near future.

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

    PubMed

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

    2015-01-01

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

  12. Final Report, "Molecular Design of Hydrocarbon Oxidation Catalytic Processes"

    SciTech Connect

    Professor Francisco Zaera

    2007-08-09

    The main goal of this project had been to use model systems to correlate selectivities in partial oxidation catalysis with the presence of specific sites on the surface of the catalyst. Extensive work was performed this year on characterizing oxygen-treated nickel surfaces by chemical means. Specifically, the surface chemistry of ammonia coadsorbed with atomic oxygen on Ni(110) single-crystal surfaces was studied by temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). It was determined that at intermediate oxygen coverages direct ammonia adsorption on nickel sites is suppressed, but a new high-temperature reaction regime is generated at 400 K where NHx surface fragments are rehydrogenated concurrently with the production of water and molecular hydrogen. The extensive isotope scrambling and hydrogen transfer seen from nitrogen- to oxygen-containing surface intermediates, and the optimum yields seen for this 400 K state at intermediate oxygen coverages, strongly suggest the direct interaction of the adsorbed ammonia with oxygen atoms at the end of the –Ni–O- rows that form upon reconstruction of the surface. Hydrogen transfer between ammonia and oxygen appears to take place directly via hydrogen bonding, and to be reversible but biased towards water formation. An equilibrium is reached between the produced water and the reacting surface oxygen and hydrogen. The strong influence of the OH surface groups on the thermal chemistry of the adsorbed ammonia was interpreted in terms of the adsorbing geometry of the OH groups on the surface, and of hydrogen bonding between adsorbed OH and NH3 species. In terms of alcohol reactivity, the adsorption of 2-iodoethanol, a precursor for the preparation of 2-hydroxyethyl and oxametallacycle surface species, was found to lead to two configurations involving either just the iodine atom or both iodine and hydroxyl ends of the molecule. A complex chemical behavior starts around 140 K with the

  13. Utilizing ToxCast Data and Lifestage Physiologically-Based Pharmacokinetic (PBPK) models to Drive Adverse Outcome Pathways (AOPs)-Based Margin of Exposures (ABME) to Chemicals.

    EPA Science Inventory

    Utilizing ToxCast Data and Lifestage Physiologically-Based Pharmacokinetic (PBPK) models to Drive Adverse Outcome Pathways (AOPs)-Based Margin of Exposures (ABME) to Chemicals. Hisham A. El-Masri1, Nicole C. Klienstreur2, Linda Adams1, Tamara Tal1, Stephanie Padilla1, Kristin I...

  14. Differentiating high priority pathway-based toxicity from non-specific effects in high throughput toxicity data: A foundation for prioritizing AOP development.

    EPA Science Inventory

    The ToxCast chemical screening approach enables the rapid assessment of large numbers of chemicals for biological effects, primarily at the molecular level. Adverse outcome pathways (AOPs) offer a means to link biomolecular effects with potential adverse outcomes at the level of...

  15. Probe molecules (PrM) approach in adverse outcome pathway (AOP) based high throughput screening (HTS): in vivo discovery for developing in vitro target methods

    EPA Science Inventory

    Efficient and accurate adverse outcome pathway (AOP) based high-throughput screening (HTS) methods use a systems biology based approach to computationally model in vitro cellular and molecular data for rapid chemical prioritization; however, not all HTS assays are grounded by rel...

  16. Advanced Oxidation of Tartrazine and Brilliant Blue with Pulsed Ultraviolet Light Emitting Diodes.

    PubMed

    Scott, Robert; Mudimbi, Patrick; Miller, Michael E; Magnuson, Matthew; Willison, Stuart; Phillips, Rebecca; Harper, Willie F

    2017-01-01

      This study investigated the effect of ultraviolet light-emitting diodes (UVLEDs) coupled with hydrogen peroxide as an advanced oxidation process (AOP) for the degradation of two test chemicals. Brilliant Blue FCF consistently exhibited greater degradation than tartrazine, with 83% degradation after 300 minutes at the 100% duty cycle compared with only 17% degradation of tartrazine under the same conditions. These differences are attributable to the structural properties of the compounds. Duty cycle was positively correlated with the first-order rate constants (k) for both chemicals but, interestingly, negatively correlated with the normalized first-order rate constants (k/duty cycle). Synergistic effects of both hydraulic mixing and LED duty cycle were manifested as novel oscillations in the effluent contaminant concentration. Further, LED output and efficiency were dependent upon duty cycle and less efficient over time perhaps due to heating effects on semiconductor performance.

  17. AOX removal from industrial wastewaters using advanced oxidation processes: assessment of a combined chemical-biological oxidation.

    PubMed

    Luyten, J; Sniegowski, K; Van Eyck, K; Maertens, D; Timmermans, S; Liers, Sven; Braeken, L

    2013-01-01

    In this paper, the abatement of adsorbable halogenated organic compounds (AOX) from an industrial wastewater containing relatively high chloride concentrations by a combined chemical and biological oxidation is assessed. For chemical oxidation, the O(3)/UV, H(2)O(2)/UV and photo-Fenton processes are evaluated on pilot scale. Biological oxidation is simulated in a 4 h respirometry experiment with periodic aeration. The results show that a selective degradation of AOX with respect to the matrix compounds (expressed as chemical oxygen demand) could be achieved. For O(3)/UV, lowering the ratio of O(3) dosage to UV intensity leads to a better selectivity for AOX. During O(3)-based experiments, the AOX removal is generally less than during the H(2)O(2)-based experiments. However, after biological oxidation, the AOX levels are comparable. For H(2)O(2)/UV, optimal operating parameters for UV and H(2)O(2) dosage are next determined in a second run with another wastewater sample.

  18. Cavitational Hydrothermal Oxidation: A New Remediation Process - Final Report

    SciTech Connect

    Suslick, K. S.

    2001-07-05

    During the past year, we have continued to make substantial scientific progress on our understanding of cavitation phenomena in aqueous media and applications of cavitation to remediation processes. Our efforts have focused on three separate areas: sonoluminescence as a probe of conditions created during cavitational collapse in aqueous media, the use of cavitation for remediation of contaminated water, and an addition of the use of ultrasound in the synthesis of novel heterogeneous catalysts for hydrodehalogenation of halocarbons under mild conditions.

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

    NASA Technical Reports Server (NTRS)

    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.

  20. Modification of coagulation and Fenton oxidation processes for cost-effective leachate treatment.

    PubMed

    Yoo, H C; Cho, S H; Ko, S O

    2001-01-01

    Physicochemical processes have been used to remove nonbiodegradable organic compounds in leachate generated from sanitary landfills. In this study, a coagulation process combined with Fenton oxidation was evaluated for the removal of refractory organics in leachate. Recycling of sludge generated from Fenton oxidation to a coagulation process was attempted to reduce operation cost and to improve organic removal rate. The addition mode of Fenton reagent was also modified to obtain a better organic removal rate and more cost-effective operation. With Fenton sludge recycling, 9% higher COD removal was obtained, and the sludge to be disposed could be reduced up to 50%. Also, the coagulant could be reduced by 50%. For Fenton oxidation process, stepwise addition of reagents gave a 5% higher COD removal, and a 25% reduction in chemical consumption.

  1. Trace metal pyritization variability in response to mangrove soil aerobic and anaerobic oxidation processes.

    PubMed

    Machado, W; Borrelli, N L; Ferreira, T O; Marques, A G B; Osterrieth, M; Guizan, C

    2014-02-15

    The degree of iron pyritization (DOP) and degree of trace metal pyritization (DTMP) were evaluated in mangrove soil profiles from an estuarine area located in Rio de Janeiro (SE Brazil). The soil pH was negatively correlated with redox potential (Eh) and positively correlated with DOP and DTMP of some elements (Mn, Cu and Pb), suggesting that pyrite oxidation generated acidity and can affect the importance of pyrite as a trace metal-binding phase, mainly in response to spatial variability in tidal flooding. Besides these aerobic oxidation effects, results from a sequential extraction analyses of reactive phases evidenced that Mn oxidized phase consumption in reaction with pyrite can be also important to determine the pyritization of trace elements. Cumulative effects of these aerobic and anaerobic oxidation processes were evidenced as factors affecting the capacity of mangrove soils to act as a sink for trace metals through pyritization processes.

  2. The impact of beef steak thermal processing on lipid oxidation and postprandial inflammation related responses.

    PubMed

    Nuora, Anu; Chiang, Vic Shao-Chih; Milan, Amber M; Tarvainen, Marko; Pundir, Shikha; Quek, Siew-Young; Smith, Greg C; Markworth, James F; Ahotupa, Markku; Cameron-Smith, David; Linderborg, Kaisa M

    2015-10-01

    Oxidised lipid species, their bioavailability and impact on inflammatory responses from cooked beef steak are poorly characterised. Oxidised lipid species from pan-fried (PF) and sous-vide (SV) thermally processed beef were determined with UHPLC-ESI/MS. Twenty-three lipid oxidation products increased with thermal processing and differences between the PF and SV steaks were measured. Fifteen oxidised lipids were measured in post-meal plasma after a cross-over randomised clinical study. Postprandial plasma inflammatory markers tended to remain lower following the SV meal than the PF meal. High levels of conjugated dienes were measured in the HDL fraction, suggesting that the protective effect of HDL may extend to the reverse-transport of oxidised lipid species. Oxidised lipids in a single meal may influence postprandial oxidative stress and inflammation. Further studies are required to examine the lipid oxidative responses to increased dietary oxidative lipid load, including the reverse transport activity of HDL.

  3. Microbial methane oxidation processes and technologies for mitigation of landfill gas emissions.

    PubMed

    Scheutz, Charlotte; Kjeldsen, Peter; Bogner, Jean E; De Visscher, Alex; Gebert, Julia; Hilger, Helene A; Huber-Humer, Marion; Spokas, Kurt

    2009-08-01

    Landfill gas containing methane is produced by anaerobic degradation of organic waste. Methane is a strong greenhouse gas and landfills are one of the major anthropogenic sources of atmospheric methane. Landfill methane may be oxidized by methanotrophic microorganisms in soils or waste materials utilizing oxygen that diffuses into the cover layer from the atmosphere. The methane oxidation process, which is governed by several environmental factors, can be exploited in engineered systems developed for methane emission mitigation. Mathematical models that account for methane oxidation can be used to predict methane emissions from landfills. Additional research and technology development is needed before methane mitigation technologies utilizing microbial methane oxidation processes can become commercially viable and widely deployed.

  4. Degradation of the commercial surfactant nonylphenol ethoxylate by advanced oxidation processes.

    PubMed

    da Silva, Salatiel Wohlmuth; Klauck, Cláudia Regina; Siqueira, Marco Antônio; Bernardes, Andréa Moura

    2015-01-23

    Four different oxidation process, namely direct photolysis (DP) and three advanced oxidation processes (heterogeneous photocatalysis - HP, eletrochemical oxidation - EO and photo-assisted electrochemical oxidation - PEO) were applied in the treatment of wastewater containing nonylphenol ethoxylate (NPnEO). The objective of this work was to determine which treatment would be the best option in terms of degradation of NPnEO without the subsequent generation of toxic compounds. In order to investigate the degradation of the surfactant, the processes were compared in terms of UV/Vis spectrum, mineralization (total organic carbon), reaction kinetics, energy efficiency and phytotoxicity. A solution containing NPnEO was prepared as a surrogate of the degreasing wastewater, was used in the processes. The results showed that the photo-assisted processes degrade the surfactant, producing biodegradable intermediates in the reaction. On the other hand, the electrochemical process influences the mineralization of the surfactant. The process of PEO carried out with a 250W lamp and a current density of 10mA/cm(2) showed the best results in terms of degradation, mineralization, reaction kinetics and energy consumption, in addition to not presenting phytotoxicity. Based on this information, this process can be a viable alternative for treating wastewater containing NPnEO, avoiding the contamination of water resources.

  5. Evaluation of long-term sulfide oxidation processes within pyrrhotite-rich tailings, Lynn Lake, Manitoba

    NASA Astrophysics Data System (ADS)

    Gunsinger, M. R.; Ptacek, C. J.; Blowes, D. W.; Jambor, J. L.

    2006-02-01

    Oxidation reactions have depleted sulfide minerals in the shallow tailings and have generated sulfate- and metal-rich pore water throughout the East Tailings Management Area (ETMA) at Lynn Lake, Manitoba, Canada. Information concerning the tailings geochemistry and mineralogy suggest the sulfide oxidation processes have reached an advanced stage in the area proximal to the point of tailings discharge. In contrast, the distal tailings, or slimes area, have a higher moisture content close to the impoundment surface, thereby impeding the ingress of oxygen and limiting sulfide oxidation. Numerical modelling of sulfide oxidation indicates the maximum rate of release for sulfate, Fe, and Ni occurred shortly after tailings deposition ceased. Although the sulfide minerals have been depleted in the very shallow tailings, the modelling suggests that sulfide oxidation will continue for hundreds and possibly thousands of years. The combination of sulfide minerals, principally pyrrhotite, that is susceptible to weathering processes and the relatively dry, coarse-grained nature of the tailings have resulted in the formation of a massive-hardpan layer in the proximal area of the ETMA. Because extensive accumulations of secondary oxyhydroxides of ferric iron are already present, remediation strategies for the ETMA should focus on mitigating the release of sulfide oxidation products rather than on preventing further oxidation.

  6. Effect of the iron oxide catalyst on o-toluidine oxidation by the fluidized-bed fenton process.

    PubMed

    Su, Chia-Chi; Fan, Chun-Cheng; Anotai, Jin; Lu, Ming-Chun

    2014-01-01

    This study investigates the effects of the Fe2+ concentration and synthetic iron oxide catalysts on o-toluidine degradation using a fluidized-bed Fenton process. The mineralization ofo-toluidine in the synthetic catalyst system is also examined. The H3.5 and H7.3 Fe/SiO2 and A7.8 and A 12.5 Fe/SiO2 catalysts were successfully synthesized by adding H202 and injecting air process, respectively. The optimum initial ferrous ion concentration for degradation of 1 mM o-toluidine was 1 mM. Experimental results reveal that 1 mM o-toluidine can be 100% degraded at 60 and 120 min in the modified fluidized-bed Fenton process with A7.8 Fe/SiO2 and the conventional fluidized-bed Fenton process with SiO2 carrier, respectively, when the optimum conditions of 1mM Fe2+ and 17mM H202 at pH 3 were used. The A7.8 Fe/SiO2 catalyst had a stronger oxidation ability than the H3.5 Fe/SiO2, H7.3 Fe/SiO2 and A12.5 Fe/SiO2 catalysts, and was attributed to the high iron content on the surface of the SiO2 support. The Fenton and Fenton-like reactions occurred in the A7.8 Fe/SiO2 catalyst system. Degradation of o-toluidine in the Fenton-like process follows pseudo-first-order kinetics. The A7.8 Fe/SiO2 catalyst efficiently enhanced o-toluidine oxidation under the pH range of 2-4.

  7. [Oxidation Process of Dissolvable Sulfide by Manganite and Its Influencing Factors].

    PubMed

    Luo, Yao; Li, Shan; Tan, Wen-feng; Liu, Fan; Cai, Chong-fa; Qiu, Guo-hong

    2016-04-15

    As one of the manganese oxides, which are easily generated and widely distributed in supergene environment, manganite participates in the oxidation of dissolvable sulfide (S²⁻), and affects the migration, transformation, and the fate of sulfides. In the present work, the redox mechanism was studied by determining the intermediates, and the influence of initial pH and oxygen atmosphere on the processes were studied. The chemical composition, crystal structures and micromorphologies were characterized by XRD, FTIR and TEM. The concentration of S²⁻ and its oxidation products were analyzed using spectrophotometer, high performance liquid chromatograph and ion chromatograph. The results indicated that elemental sulfur was formed as the major oxidation product of S²⁻ oxidation, and decreased pH could accelerate the oxidation rate of S²⁻ in the initial stage, however, there was no significant influence on final products. Elemental S could be further oxidized to S₂O₃²⁻ when the reaction system was bubbled with oxygen, and manganite exhibited excellent catalytic performance and chemical stability during the oxidation of dissolvable sulfide by oxygen. After reaction of more than 10 h, the crystal structure of manganite remained stable.

  8. Principal Methods and Apparatus for Investigating Oxidation Processes in Metal and Alloys. USSR

    DTIC Science & Technology

    1960-09-14

    stage is characterized by direct interaction of the metal with the oxidizing reagent and actually represents chemical adsorbtion (or, more exactly...physical adsorbtion , changing rapidly to chemical adsorbtlon). For almost all metals and alloys this stage proceeds very rapidly even at room temperature...process in this stage has little significance (by comparison with the heat of formation of the oxide). An indirect confirmation of th.ei;s contention is the

  9. Development of a Scalable Process Control System for Chemical Soil Washing to Remove Uranyl Oxide

    DTIC Science & Technology

    2015-05-01

    is reactive, oxidizing once it has been deposited into soil. The recovery process needs a variety of measurement systems for precisely locating the...medical imaging material, etc.), toxic or hazardous materials such as pesticides or asbestos , consumer products such as refrigerators or...2012), the soil fines remain contaminated by tightly bound DU oxides. The leaching system removes uranium from these soil fines and deposits the

  10. Kinetics and mechanism of the oxidation process of two-component Fe-Al alloys

    NASA Technical Reports Server (NTRS)

    Przewlocka, H.; Siedlecka, J.

    1982-01-01

    The oxidation process of two-component Fe-Al alloys containing up to 7.2% Al and from 18 to 30% Al was studied. Kinetic measurements were conducted using the isothermal gravimetric method in the range of 1073-1223 K and 1073-1373 K for 50 hours. The methods used in studies of the mechanism of oxidation included: X-ray microanalysis, X-ray structural analysis, metallographic analysis and marker tests.

  11. Occurrence and Removal of Organic Micropollutants in Landfill Leachates Treated by Electrochemical Advanced Oxidation Processes.

    PubMed

    Oturan, Nihal; van Hullebusch, Eric D; Zhang, Hui; Mazeas, Laurent; Budzinski, Hélène; Le Menach, Karyn; Oturan, Mehmet A

    2015-10-20

    In recent years, electrochemical advanced oxidation processes have been shown to be an effective alternative for the removal of refractory organic compounds from water. This study is focused on the effective removal of recalcitrant organic matter (micropollutants, humic substances, etc.) present in municipal solid waste landfill leachates. A mixture of eight landfill leachates has been studied by the electro-Fenton process using a Pt or boron-doped diamond (BDD) anode and a carbon felt cathode or by the anodic oxidation process with a BDD anode. These processes exhibit great oxidation ability due to the in situ production of hydroxyl radicals ((•)OH), a highly powerful oxidizing species. Both electrochemical processes were shown to be efficient in the removal of dissolved total organic carbon (TOC) from landfill leachates. Regarding the electro-Fenton process, the replacement of the classical anode Pt by the anode BDD allows better performance in terms of dissolved TOC removal. The occurrence and removal yield of 19 polycyclic aromatic hydrocarbons, 15 volatile organic compounds, 7 alkylphenols, 7 polychlorobiphenyls, 5 organochlorine pesticides, and 2 polybrominated diphenyl ethers in landfill leachate were also investigated. Both electrochemical processes allow one to reach a quasicomplete removal (about 98%) of these organic micropollutants.

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

    SciTech Connect

    György, E.; Pérez del Pino, A.; Logofatu, C.; Duta, A.; Isac, L.

    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.

  13. P-type conductive amorphous oxides of transition metals from solution processing

    NASA Astrophysics Data System (ADS)

    Li, Jinwang; Kaneda, Toshihiko; Tokumitsu, Eisuke; Koyano, Mikio; Mitani, Tadaoki; Shimoda, Tatsuya

    2012-07-01

    We report a series of solution-processed p-type conductive amorphous Ln-M-O (a-Ln-M-O, where M = Ru, Ir, and Ln is a lanthanide element except Ce) having low resistivities (10-3 to 10-2 Ω cm). These oxides are thermally stable to a high degree, being amorphous up to 800 °C, and processable below 400 °C. Their film surfaces are smooth on the atomic scale, and the process allows patterning simply by direct imprinting without distortion of the pattern after annealing. These properties have high potential for use in printed electronics. The electron configurations of these oxides are apparently different from existing p-type oxides.

  14. Sludge thermal oxidation processes: mineral recycling, energy impact, and greenhouse effect gases release.

    PubMed

    Guibelin, E

    2004-01-01

    Different treatment routes have been studied for a mixed sludge: the conventional agricultural use is compared with the thermal oxidation processes, including incineration (in gaseous phase) and wet air oxidation (in liquid phase). The interest of a sludge digestion prior to the final treatment has been also considered according to the two major criteria, which are the fossil energy utilisation and the greenhouse effect gases (CO2, CH4, N2O) release. Thermal energy has to be recovered on thermal processes to make these processes environmentally friendly, otherwise their main interest is to extract or destroy micropollutants and pathogens from the carbon cycle. In case of continuous energy recovery, incineration can produce more energy than it consumes. Digestion is especially interesting for agriculture: according to these two schemes, the energy final balance can also be in excess. As to wet air oxidation, it is probably one of the best ways to minimize greenhouse effect gases emission.

  15. Rapid decolorization of azo dyes in aqueous solution by an ultrasound-assisted electrocatalytic oxidation process.

    PubMed

    Ai, Zhihui; Li, Jinpo; Zhang, Lizhi; Lee, Shuncheng

    2010-02-01

    In this study, we developed a novel ultrasound-assisted electrocatalytic oxidation (US-EO) process to decolorize azo dyes in aqueous solution. Rhodamine B was decolorized completely within several minutes in this developed US-EO system. Oxidation parameters such as applied potentials, power of the ultrasound, initial pH of the solution, and initial concentration of RhB were systematically studied and optimized. An obvious synergistic effect was found in decolorization of RhB by the US-EO process when comparing with either ultrasound (US) process or electrocatalytic oxidation (EO) one. Additionally, the decolorization of other azo dyes, such as methylene blue, reactive brilliant red X-3B, and methyl orange, were also effective in the US-EO system. The results indicated that US-EO system was effective for the decolorization of azo dyes, suggesting its great potential in dyeing wastewater treatment.

  16. Processing and mechanical behavior of aluminium oxide microstructure composites

    NASA Astrophysics Data System (ADS)

    Pavlacka, Robert J.

    concluded that densification was impeded by the dopant at lower temperatures but enhanced significantly above 1450°C. Texture is highly developed in samples with no dopant and 0.14 wt% dopant by 1550°C and in samples with 2 wt% dopant by 1350°C. We proposed a new class of composites (called microstructure composites) that accesses different component properties not through the use of distinct materials, but rather through the exploitation of the microstructure-property relationship within a single material. Microstructure composites, therefore, are single phase ceramics that combine components with distinct microstructures within a single composite to obtain unique property combinations. Spatial control and composite connectivity of the individual microstructural 'components' of a microstructure composite are ultimately the key to developing and controlling useful and unique properties. Microstructural components are developed by controlling the starting location and transport of dopants during processing and sintering. This work focuses on alpha-Al2O3 microstructure composites that combine textured components, developed in situ using templated grain growth (TGG), and fine-grained equiaxed components. To control microstructure development locally during composite fabrication, it is important to use relatively low levels of dopant to mitigate the effects of dopant interdiffusion. Therefore, the development of texture in alpha-Al 2O3 using low liquid-phase dopant concentrations was explored, with a focus on the effect of template constraint on texture plane shrinkage. High quality texture was obtained with just 0.14 wt% (SiO2 + CaO) dopant. Textured Al2O3 exhibited transgranular fracture, as well as lower strength and fracture toughness than the fine-grained equiaxed Al2O3. A processing strategy using tape casting was developed for the fabrication of textured-equiaxed Al2O3 microstructure composites with 2-2 connectivity. Dopants used t