WorldWideScience

Sample records for oxidative water treatment

  1. Application of graphene oxide in water treatment

    Science.gov (United States)

    Liu, Yongchen

    2017-11-01

    Graphene oxide has good hydrophilicity and has been tried to use it into thin films for water treatment in recent years. In this paper, the preparation methods of graphene oxide membrane are reviewed, including vacuum suction filtration, spray coating, spin coating, dip coating and the layer by layer method. Secondly, the mechanism of mass transfer of graphene membrane is introduced in detail. The application of the graphene oxide membrane, modified graphene oxide membrane and graphene hybrid membranes were discussed in RO, vaporization, nanofiltration and other aspects. Finally, the development and application of graphene membrane in water treatment were discussed.

  2. Effect of metal oxide nanoparticles on Godavari river water treatment

    Science.gov (United States)

    Goud, Ravi Kumar; Ajay Kumar, V.; Reddy, T. Rakesh; Vinod, B.; Shravani, S.

    2018-05-01

    Nowadays there is a continuously increasing worldwide concern for the development of water treatment technologies. In the area of water purification, nanotechnology offers the possibility of an efficient removal of pollutants and germs. Nanomaterials reveal good results than other techniques used in water treatment because of its high surface area to volume ratio. In the present work, iron oxide and copper oxide nanoparticles were synthesized by simple heating method. The synthesized nanoparticles were used to purify Godavari river water. The effect of nanoparticles at 70°C temperature, 12 centimeter of sand bed height and pH of 8 shows good results as compared to simple sand bed filter. The attained values of BOD5, COD and Turbidity were in permissible limit of world health organization.

  3. Supercritical water oxidation treatment of textile sludge.

    Science.gov (United States)

    Zhang, Jie; Wang, Shuzhong; Li, Yanhui; Lu, Jinling; Chen, Senlin; Luo, XingQi

    2017-08-01

    In this work, we studied the supercritical water oxidation (SCWO) of the textile sludge, the hydrothermal conversion of typical textile compounds and the corrosion properties of stainless steel 316. Moreover, the influence mechanisms of NaOH during these related processes were explored. The results show that decomposition efficiency for organic matter in liquid phase of the textile sludge was improved with the increment of reaction temperature or oxidation coefficient. However, the organic substance in solid phase can be oxidized completely in supercritical water. Serious coking occurred during the high pressure water at 250-450°C for the Reactive Orange 7, while at 300 and 350°C for the polyvinyl alcohol. The addition of NaOH not only accelerated the destruction of organic contaminants in the SCWO reactor, but effectively inhibited the dehydration conversion of textile compounds during the preheating process, which was favorable for the treatment system of textile sludge. The corrosion experiment results indicate that the stainless steel 316 could be competent for the body materials of the reactor and the heat exchangers. Furthermore, there was prominent enhancement of sodium hydroxide for the corrosion resistance of 316 in subcritical water. On the contrary the effect was almost none during SCWO.

  4. Bromorhodamines - new singlet oxygen photosensitizers for oxidative water and wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Slivka, L.; Alekseeva, V.; Kuznetsova, N.; Marinina, L.; Savvina, L.; Kaliya, O.; Lukyanets, E.; Vorozhtsov, G. [Organic Intermediates and Dyes Inst., Moscow (Russian Federation); Krasnovsky, A.; Butorina, D. [Inst. of Biochemistry RAS, Moscow (Russian Federation)

    2003-07-01

    The cationic mono-, di- and tetrabromoderivatives of rhodamine 123 have been synthesized and studied as sensitizers for singlet oxygen formation in application for oxidative water treatment. Singlet oxygen quantum yields for compounds under investigation have been determined by using its near IR luminescence at 1270 nm. Bromorhodamines123 have been shown to sensitize the formation of singlet oxygen in aqueous solution with high quantum yields. Efficient oxidation of tryptophan in aqueous solutions sensitized by dibromorhodamine 123 has been demonstrated. This dye was tested as sensitizer for photodynamic treatment of water contaminated with coliform bacteria. It was shown to participate in the photosensitization of coliform bacteria, resulting in their efficient killing. (orig.)

  5. Electrochemical advanced oxidation processes as decentralized water treatment technologies to remediate domestic washing machine effluents.

    Science.gov (United States)

    Dos Santos, Alexsandro Jhones; Costa, Emily Cintia Tossi de Araújo; da Silva, Djalma Ribeiro; Garcia-Segura, Sergi; Martínez-Huitle, Carlos Alberto

    2018-03-01

    Water scarcity is one of the major concerns worldwide. In order to secure this appreciated natural resource, management and development of water treatment technologies are mandatory. One feasible alternative is the consideration of water recycling/reuse at the household scale. Here, the treatment of actual washing machine effluent by electrochemical advanced oxidation processes was considered. Electrochemical oxidation and electro-Fenton technologies can be applied as decentralized small-scale water treatment devices. Therefore, efficient decolorization and total organic abatement have been followed. The results demonstrate the promising performance of solar photoelectro-Fenton process, where complete color and organic removal was attained after 240 min of treatment under optimum conditions by applying a current density of 66.6 mA cm -2 . Thus, electrochemical technologies emerge as promising water-sustainable approaches.

  6. Successful treatment with supercritical water oxidation

    International Nuclear Information System (INIS)

    Jensen, R.

    1994-01-01

    Supercritical Water Oxidation (SCWO) operates in a totally enclosed system. It uses water at high temperatures and high pressure to chemically change wastes. Oily substances become soluble and complex hydrocarbons are converted into water and carbon dioxide. Research and development on SCWO is described

  7. Water-Mediated Photochemical Treatments for Low-Temperature Passivation of Metal-Oxide Thin-Film Transistors.

    Science.gov (United States)

    Heo, Jae Sang; Jo, Jeong-Wan; Kang, Jingu; Jeong, Chan-Yong; Jeong, Hu Young; Kim, Sung Kyu; Kim, Kwanpyo; Kwon, Hyuck-In; Kim, Jaekyun; Kim, Yong-Hoon; Kim, Myung-Gil; Park, Sung Kyu

    2016-04-27

    The low-temperature electrical passivation of an amorphous oxide semiconductor (AOS) thin-film transistor (TFT) is achieved by a deep ultraviolet (DUV) light irradiation-water treatment-DUV irradiation (DWD) method. The water treatment of the first DUV-annealed amorphous indium-gallium-zinc-oxide (a-IGZO) thin film is likely to induce the preferred adsorption of water molecules at the oxygen vacancies and leads to subsequent hydroxide formation in the bulk a-IGZO films. Although the water treatment initially degraded the electrical performance of the a-IGZO TFTs, the second DUV irradiation on the water-treated devices may enable a more complete metal-oxygen-metal lattice formation while maintaining low oxygen vacancies in the oxide films. Overall, the stable and dense metal-oxygen-metal (M-O-M) network formation could be easily achieved at low temperatures (below 150 °C). The successful passivation of structural imperfections in the a-IGZO TFTs, such as hydroxyl group (OH-) and oxygen vacancies, mainly results in the enhanced electrical performances of the DWD-processed a-IGZO TFTs (on/off current ratio of 8.65 × 10(9), subthreshold slope of 0.16 V/decade, an average mobility of >6.94 cm(2) V(-1) s(-1), and a bias stability of ΔVTH IGZO TFTs.

  8. DNA damage and oxidative stress in human liver cell L-02 caused by surface water extracts during drinking water treatment in a waterworks in China.

    Science.gov (United States)

    Xie, Shao-Hua; Liu, Ai-Lin; Chen, Yan-Yan; Zhang, Li; Zhang, Hui-Juan; Jin, Bang-Xiong; Lu, Wen-Hong; Li, Xiao-Yan; Lu, Wen-Qing

    2010-04-01

    Because of the daily and life-long exposure to disinfection by-products formed during drinking water treatment, potential adverse human health risk of drinking water disinfection is of great concern. Toxicological studies have shown that drinking water treatment increases the genotoxicity of surface water. Drinking water treatment is comprised of different potabilization steps, which greatly influence the levels of genotoxic products in the surface water and thus may alter the toxicity and genotoxicity of surface water. The aim of the present study was to understand the influence of specific steps on toxicity and genotoxicity during the treatment of surface water in a water treatment plant using liquid chlorine as the disinfectant in China. An integrated approach of the comet and oxidative stress assays was used in the study, and the results showed that both the prechlorination and postchlorination steps increased DNA damage and oxidative stress caused by water extracts in human derived L-02 cells while the tube settling and filtration steps had the opposite effect. This research also highlighted the usefulness of an integrated approach of the comet and oxidative stress assays in evaluating the genotoxicity of surface water during drinking water treatment. Copyright 2009 Wiley-Liss, Inc.

  9. Transformation of pharmaceuticals during oxidation/disinfection processes in drinking water treatment.

    Science.gov (United States)

    Postigo, Cristina; Richardson, Susan D

    2014-08-30

    Pharmaceuticals are emerging contaminants of concern and are widespread in the environment. While the levels of these substances in finished drinking waters are generally considered too low for human health concern, there are now concerns about their disinfection by-products (DBPs) that can form during drinking water treatment, which in some cases have been proven to be more toxic than the parent compounds. The present manuscript reviews the transformation products of pharmaceuticals generated in water during different disinfection processes, i.e. chlorination, ozonation, chloramination, chlorine dioxide, UV, and UV/hydrogen peroxide, and the main reaction pathways taking place. Most of the findings considered for this review come from controlled laboratory studies involving reactions of pharmaceuticals with these oxidants used in drinking water treatment. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Bench-scale study of the effect of phosphate on an aerobic iron oxidation plant for mine water treatment.

    Science.gov (United States)

    Tischler, Judith S; Wiacek, Claudia; Janneck, Eberhard; Schlömann, Michael

    2014-01-01

    At the opencast pit Nochten acidic iron- and sulfate-rich mine waters are treated biotechnologically in a mine-water treatment plant by microbial iron oxidation. Due to the low phosphate concentration in such waters the treatment plant was simulated in bench-scale to investigate the influence of addition of potassium dihydrogen phosphate on chemical and biological parameters of the mine-water treatment. As a result of the phosphate addition the number of cells increased, which resulted in an increase of the iron oxidation rate in the reactor with phosphate addition by a factor of 1.7 compared to a reference approach without phosphate addition. Terminal restriction fragment length polymorphism (T-RFLP) analysis during the cultivation revealed a shift of the microbial community depending on the phosphate addition. While almost exclusively iron-oxidizing bacteria related to "Ferrovum" sp. were detected with phosphate addition, the microbial community was more diverse without phosphate addition. In the latter case, iron-oxidizing bacteria ("Ferrovum" sp., Acidithiobacillus spp.) as well as non-iron-oxidizing bacteria (Acidiphilium sp.) were identified. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Characterization of the oxide grown on Zr-20 Nb with different heat treatments in water at high temperature

    International Nuclear Information System (INIS)

    Olmedo, Ana M.; Bordoni, Roberto; Koenig, Patricia

    2003-01-01

    This work presents the corrosion behaviour of Zr-20 Nb alloy with different heat treatments. All the samples were annealed at 850 C degrees for one hour and cooled in air. After this heat treatment the sample coupons were aged at different temperatures and times. The corrosion kinetic of the different coupon samples were determined in water at 315 C degrees. The microstructure of the oxides were analysed using X-ray diffraction. The oxides grown in water steam at 400 C degrees, in coupons with a β Zr microstructure and in coupons aged in order to obtain a α Zr· + β Nb microstructure were also analysed. The oxides grown at the different temperatures and for all the microstructures were very adherent and black for all the times studied. The corrosion kinetics showed that the aging treatments decrease the corrosion rate of this material in degassed water at 315 C degrees and also in water steam at 400 C degrees. The greatest corrosion resistance is achieved for the equilibrium or near equilibrium microstructure of the samples and the presence of the · phase does not decrease the corrosion resistance of the material. The microstructure analysis of the oxides indicated that oxides grown on samples with β Zr microstructure are composed mainly by a Zr-Nb oxide of the type Nb 2 O 5· 6ZrO 2 , together with a small fraction of monoclinic ZrO 2 . Aging treatments produce an increase of the monoclinic phase and diminish the proportion of the mixed oxide. When the aging treatment gives the equilibrium or near equilibrium microstructure of α Zr· + β Nb , the oxide is composed mainly of monoclinic ZrO 2 , a small proportion of tetragonal component and also Nb 2 O 5 . (author)

  12. Water purification by corona-above-water treatment

    NARCIS (Netherlands)

    Pemen, A.J.M.; Heesch, van E.J.M.; Hoeben, W.F.L.M.

    2012-01-01

    Advanced oxidation technologies (AOT), such as non-thermal plasmas, are considered to be very promising for the purpose of water treatment. The goal of this study is to test the feasibility of "Corona-above-water" technology for the treatment of drinking water. Experiments have been performed on the

  13. Electro-oxidation of reverse osmosis concentrates generated in tertiary water treatment.

    Science.gov (United States)

    Pérez, G; Fernández-Alba, A R; Urtiaga, A M; Ortiz, I

    2010-05-01

    This work investigates the application of the electro-oxidation technology provided with boron doped diamond (BDD), an electrode material which has shown outstanding properties in oxidation of organic and inorganic compounds, for the treatment of reverse osmosis (RO) concentrates generated in tertiary wastewater treatment plants (WWTP). Chemical oxygen demand (COD), ammonium and several anions were measured during the electro-oxidation process, and the influence of the applied current density (20-200A/m(2)) was analysed on process kinetics. Analytical assessment showed that several emerging pollutants (pharmaceuticals, personal care products, stimulants, etc.) were presented both in the effluent of the secondary WWTP as well as in the RO concentrate. For this reason, a group of 10 emerging pollutants, those found with higher concentrations, was selected in order to test whether electro-oxidation can be also applied for their mitigation. In the removal of emerging pollutants the electrical current density in the range 20-100A/m(2) did not show influence likely due to the mass transfer resistance developed in the process when the oxidized solutes are present in such low concentrations. Their removal rates were fitted to first order expressions, and the apparent kinetic constants for the anodic oxidation of each compound were calculated. Finally, the formation of trihalomethanes (THMs) has been checked; concluding that after selecting the appropriate operational conditions the attained concentration is lower than the standards for drinking water established in European and EPA regulations. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  14. Permanganate oxidation of sulfur compounds to prevent poisoning of Pd catalysts in water treatment processes.

    Science.gov (United States)

    Angeles-Wedler, Dalia; Mackenzie, Katrin; Kopinke, Frank-Dieter

    2008-08-01

    The practical application of Pd-catalyzed water treatment processes is impeded by catalyst poisoning by reduced sulfur compounds (RSCs). In this study, the potential of permanganate as a selective oxidant for the removal of microbially generated RSCs in water and as a regeneration agent for S-poisoned catalysts was evaluated. Hydrodechlorination using Pd/Al2O3 was carried out as a probe reaction in permanganate-pretreated water. The activity of the Pd catalysts in the successfully pretreated reaction medium was similar to that in deionized water. The catalyst showed no deactivation behavior in the presence of permanganate at a concentration level or = 0.08 mM, a significant but temporary inhibition of the catalytic dechlorination was observed. Unprotected Pd/Al2O3, which had been completely poisoned by sulfide, was reactivated by a combined treatment with permanganate and hydrazine. However, the anthropogenic water pollutants thiophene and carbon disulfide were resistant against permanganate. Together with the preoxidation of catalyst poisons, hydrophobic protection of the catalysts was studied. Pd/zeolite and various hydrophobically coated catalysts showed a higher stability against ionic poisons and permanganate than the uncoated catalyst. By means of a combination of oxidative water pretreatment and hydrophobic catalyst protection, we provide a new tool to harness the potential of Pd-catalyzed hydrodehalogenation for the treatment of real waters.

  15. Fate of citalopram during water treatment with O3, ClO2, UV and fenton oxidation

    DEFF Research Database (Denmark)

    Hörsing, Maritha; Kosjek, Tina; Andersen, Henrik Rasmus

    2012-01-01

    In the present study we investigate the fate of citalopram (CIT) at neutral pH using advanced water treatment technologies that include O3, ClO2 oxidation, UV irradiation and Fenton oxidation. The ozonation resulted in 80% reduction after 30 min treatment. Oxidation with ClO2 removed >90% CIT...... at a dosage of 0.1 mg L−1. During UV irradiation 85% reduction was achieved after 5 min, while Fenton with addition of 14 mg L−1 (Fe2+) resulted in 90% reduction of CIT. During these treatment experiments transformation products (TPs) were formed from CIT, where five compounds were identified by using high...

  16. Protein-functionalized magnetic iron oxide nanoparticles: time efficient potential-water treatment

    International Nuclear Information System (INIS)

    Okoli, Chuka; Boutonnet, Magali; Järås, Sven; Rajarao-Kuttuva, Gunaratna

    2012-01-01

    Recent advances in nanoscience suggest that the existing issues involving water quality could be resolved or greatly improved using nanomaterials, especially magnetic iron oxide nanoparticles. Magnetic nanoparticles have been synthesized for the development and use, in association with natural coagulant protein for water treatment. The nanoparticles size, morphology, structure, and magnetic properties were characterized by transmission electron microscope, X-ray diffraction, and superconducting quantum interference device magnetometry. Purified Moringa oleifera protein was attached onto microemulsions-prepared magnetic iron oxide nanoparticles (ME-MION) to form stable protein-functionalized magnetic nanoparticles (PMO+ME-MION). The turbidity removal efficiency in both synthetic and surface water samples were investigated and compared with the commonly used synthetic coagulant (alum) as well as PMO. More than 90 % turbidity could be removed from the surface waters within 12 min by magnetic separation of PMO+ME-MION; whereas gravimetrically, 70 % removal in high and low turbid waters can be achieved within 60 min. In contrast, alum requires 180 min to reduce the turbidity of low turbid water sample. These data support the advantage of separation with external magnetic field (magnetophoresis) over gravitational force. Time kinetics studies show a significant enhancement in ME-MION efficiency after binding with PMO implying the availability of large surface of the ME-MION. The coagulated particles (impurities) can be removed from PMO+ME-MION by washing with mild detergent or cleaning solution. To our knowledge, this is the first report on surface water turbidity removal using protein-functionalized magnetic nanoparticle.

  17. Protein-functionalized magnetic iron oxide nanoparticles: time efficient potential-water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Okoli, Chuka [Royal Institute of Technology (KTH), Environmental Microbiology (Sweden); Boutonnet, Magali; Jaeras, Sven [Royal Institute of Technology (KTH), Chemical Technology (Sweden); Rajarao-Kuttuva, Gunaratna, E-mail: gkr@kth.se [Royal Institute of Technology (KTH), Environmental Microbiology (Sweden)

    2012-10-15

    Recent advances in nanoscience suggest that the existing issues involving water quality could be resolved or greatly improved using nanomaterials, especially magnetic iron oxide nanoparticles. Magnetic nanoparticles have been synthesized for the development and use, in association with natural coagulant protein for water treatment. The nanoparticles size, morphology, structure, and magnetic properties were characterized by transmission electron microscope, X-ray diffraction, and superconducting quantum interference device magnetometry. Purified Moringa oleifera protein was attached onto microemulsions-prepared magnetic iron oxide nanoparticles (ME-MION) to form stable protein-functionalized magnetic nanoparticles (PMO+ME-MION). The turbidity removal efficiency in both synthetic and surface water samples were investigated and compared with the commonly used synthetic coagulant (alum) as well as PMO. More than 90 % turbidity could be removed from the surface waters within 12 min by magnetic separation of PMO+ME-MION; whereas gravimetrically, 70 % removal in high and low turbid waters can be achieved within 60 min. In contrast, alum requires 180 min to reduce the turbidity of low turbid water sample. These data support the advantage of separation with external magnetic field (magnetophoresis) over gravitational force. Time kinetics studies show a significant enhancement in ME-MION efficiency after binding with PMO implying the availability of large surface of the ME-MION. The coagulated particles (impurities) can be removed from PMO+ME-MION by washing with mild detergent or cleaning solution. To our knowledge, this is the first report on surface water turbidity removal using protein-functionalized magnetic nanoparticle.

  18. Protein-functionalized magnetic iron oxide nanoparticles: time efficient potential-water treatment

    Science.gov (United States)

    Okoli, Chuka; Boutonnet, Magali; Järås, Sven; Rajarao-Kuttuva, Gunaratna

    2012-10-01

    Recent advances in nanoscience suggest that the existing issues involving water quality could be resolved or greatly improved using nanomaterials, especially magnetic iron oxide nanoparticles. Magnetic nanoparticles have been synthesized for the development and use, in association with natural coagulant protein for water treatment. The nanoparticles size, morphology, structure, and magnetic properties were characterized by transmission electron microscope, X-ray diffraction, and superconducting quantum interference device magnetometry. Purified Moringa oleifera protein was attached onto microemulsions-prepared magnetic iron oxide nanoparticles (ME-MION) to form stable protein-functionalized magnetic nanoparticles (PMO+ME-MION). The turbidity removal efficiency in both synthetic and surface water samples were investigated and compared with the commonly used synthetic coagulant (alum) as well as PMO. More than 90 % turbidity could be removed from the surface waters within 12 min by magnetic separation of PMO+ME-MION; whereas gravimetrically, 70 % removal in high and low turbid waters can be achieved within 60 min. In contrast, alum requires 180 min to reduce the turbidity of low turbid water sample. These data support the advantage of separation with external magnetic field (magnetophoresis) over gravitational force. Time kinetics studies show a significant enhancement in ME-MION efficiency after binding with PMO implying the availability of large surface of the ME-MION. The coagulated particles (impurities) can be removed from PMO+ME-MION by washing with mild detergent or cleaning solution. To our knowledge, this is the first report on surface water turbidity removal using protein-functionalized magnetic nanoparticle.

  19. Population dynamics of iron-oxidizing communities in pilot plants for the treatment of acid mine waters.

    Science.gov (United States)

    Heinzel, Elke; Janneck, Eberhard; Glombitza, Franz; Schlömann, Michael; Seifert, Jana

    2009-08-15

    The iron-oxidizing microbial community in two pilot plants for the treatment of acid mine water was monitored to investigate the influence of different process parameters such as pH, iron concentration, and retention time on the stability of the system to evaluate the applicability of this treatment technology on an industrial scale. The dynamics of the microbial populations were followed using T-RFLP (terminal restriction fragment length polymorphism) over a period of several months. For a more precise quantification, two TaqMan assays specific for the two prominent groups were developed and the relative abundance of these taxa in the iron-oxidizing community was verified by real-time PCR. The investigations revealed that the iron-oxidizing community was clearly dominated by two groups of Betaproteobacteria affiliated with the poorly known and not yet recognized species "Ferrovum myxofaciens" and with strains related to Gallionella ferruginea, respectively. These taxa dominated the microbial community during the whole investigation period and accelerated the oxidation of ferrous iron despite the changing characteristics of mine waters flowing into the plants. Thus, it is assumed that the treatment technology can also be applied to other mine sites and that these organisms play a crucial role in such treatment systems.

  20. Advanced oxidation in waste water treatment; Oxidacion avanzada en el tratamiento de aguas residuales

    Energy Technology Data Exchange (ETDEWEB)

    Baraza, J.; Esplugas, S. [Universitat de Barcelona (Spain)

    2000-07-01

    The treatment of waste waters and, sometimes, drinking water, using advanced oxidation processes is reviewed on the basis of the studies carried out in which the hydroxyl radical plays an important part, with different techniques and reagents offering a broad range of possibilities. A distinction is made between photochemical an non-photochemical processes. A simple presentation of the fundamentals of each method is made together with a wide-ranging review of the literature and the results obtained in the degradation of certain contaminants resistant to conventional chemical treatments. (Author) 43 refs.

  1. Study of Advanced Oxidation System for Water Treatment

    International Nuclear Information System (INIS)

    Widdi Usada; Bambang Siswanto; Suryadi; Agus Purwadi; Isyuniarto

    2007-01-01

    Hygiene water is still a big problem globally as well as energy and food, especially in Indonesia where more than 70 % lived in Java island. One of the efforts in treating hygiene water is to recycle the used water. In this case it is needed clean water technology. Many methods have been done, this paper describes the advanced oxidation technology system based on ozone, titania and plasma discharge. (author)

  2. Transformation of pharmaceuticals during oxidation/disinfection processes in drinking water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Postigo, Cristina [Institute for Environmental Assessment and Water Research (IDAEA)—Spanish National Research Council (CID-CSIC), Barcelona (Spain); Richardson, Susan D., E-mail: richardson.susan@sc.edu [Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC (United States)

    2014-08-30

    Graphical abstract: - Highlights: • Review of transformation pathways of pharmaceuticals during disinfection processes. • DBPs are formed with chlorine, chloramine, ozone, chlorine dioxide, UV, or UV/H{sub 2}O{sub 2}. • Chlorine reacts with amine and reduced sulfur groups and activated aromatic systems. • Chlorine dioxide and ozone react with electron-rich functional groups. • Potential health effects are noted for some pharmacuetical DBPs when available. - Abstract: Pharmaceuticals are emerging contaminants of concern and are widespread in the environment. While the levels of these substances in finished drinking waters are generally considered too low for human health concern, there are now concerns about their disinfection by-products (DBPs) that can form during drinking water treatment, which in some cases have been proven to be more toxic than the parent compounds. The present manuscript reviews the transformation products of pharmaceuticals generated in water during different disinfection processes, i.e. chlorination, ozonation, chloramination, chlorine dioxide, UV, and UV/hydrogen peroxide, and the main reaction pathways taking place. Most of the findings considered for this review come from controlled laboratory studies involving reactions of pharmaceuticals with these oxidants used in drinking water treatment.

  3. Transformation of pharmaceuticals during oxidation/disinfection processes in drinking water treatment

    International Nuclear Information System (INIS)

    Postigo, Cristina; Richardson, Susan D.

    2014-01-01

    Graphical abstract: - Highlights: • Review of transformation pathways of pharmaceuticals during disinfection processes. • DBPs are formed with chlorine, chloramine, ozone, chlorine dioxide, UV, or UV/H 2 O 2 . • Chlorine reacts with amine and reduced sulfur groups and activated aromatic systems. • Chlorine dioxide and ozone react with electron-rich functional groups. • Potential health effects are noted for some pharmacuetical DBPs when available. - Abstract: Pharmaceuticals are emerging contaminants of concern and are widespread in the environment. While the levels of these substances in finished drinking waters are generally considered too low for human health concern, there are now concerns about their disinfection by-products (DBPs) that can form during drinking water treatment, which in some cases have been proven to be more toxic than the parent compounds. The present manuscript reviews the transformation products of pharmaceuticals generated in water during different disinfection processes, i.e. chlorination, ozonation, chloramination, chlorine dioxide, UV, and UV/hydrogen peroxide, and the main reaction pathways taking place. Most of the findings considered for this review come from controlled laboratory studies involving reactions of pharmaceuticals with these oxidants used in drinking water treatment

  4. Catalytic oxidation of sulfide in drinking water treatment: activated carbon as catalyst; Katalytische Oxidation von Sulfid bei der Trinkwasseraufbereitung: Aktivkohle als Katalysator

    Energy Technology Data Exchange (ETDEWEB)

    Hultsch, V; Grischek, T; Wolff, D; Worch, E [Technische Univ. Dresden (Germany). Inst. fuer Wasserchemie; Gun, J [Hebrew Univ. of Jerusalem (Israel). Div. of Environmental Sciences, Fredy and Nadine Herrmann School of Applied Science

    2001-07-01

    In regions with warm climate and limited water resources high sulfide concentrations in groundwater can cause problems during drinking water treatment. Aeration of the raw water is not always sufficient to ensure the hydrogen sulfide concentration below the odour threshold value for hydrogen sulfide. As an alternative, activated carbon can be used as a catalyst for sulfide oxidation of raw water. The use of different types of activated carbon was investigated in kinetic experiments. Both Catalytic Carbon from Calgon Carbon and granulated activated carbon from Norit showed high catalytic activities. The results of the experiments are discussed with regard to the practical use of activated carbon for the elimination of hydrogen sulfide during drinking water treatment. (orig.)

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

    International Nuclear Information System (INIS)

    Piccinno, T.; Salluzzo, A.; Nardi, L.; Gili, M.; Luce, A.; Troiani, F.; Cornacchia, G.

    1989-11-01

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

  6. N-nitrosodimethylamine (NDMA) formation potential of amine-based water treatment polymers: Effects of in situ chloramination, breakpoint chlorination, and pre-oxidation.

    Science.gov (United States)

    Park, Sang Hyuck; Padhye, Lokesh P; Wang, Pei; Cho, Min; Kim, Jae-Hong; Huang, Ching-Hua

    2015-01-23

    Recent studies show that cationic amine-based water treatment polymers may be important precursors that contribute to formation of the probable human carcinogen N-nitrosodimethylamine (NDMA) during water treatment and disinfection. To better understand how water treatment parameters affect NDMA formation from the polymers, the effects of in situ chloramination, breakpoint chlorination, and pre-oxidation on the NDMA formation from the polymers were investigated. NDMA formation potential (NDMA-FP) as well as dimethylamine (DMA) residual concentration were measured from poly(epichlorohydrin dimethylamine) (polyamine) and poly(diallyldimethylammonium chloride) (polyDADMAC) solutions upon reactions with oxidants including free chlorine, chlorine dioxide, ozone, and monochloramine under different treatment conditions. The results supported that dichloramine (NHCl2) formation was the critical factor affecting NDMA formation from the polymers during in situ chloramination. The highest NDMA formation from the polymers occurred near the breakpoint of chlorination. Polymer chain breakdown and transformation of the released DMA and other intermediates were important factors affecting NDMA formation from the polymers in pre-oxidation followed by post-chloramination. Pre-oxidation generally reduced NDMA-FP of the polymers; however, the treatments involving pre-ozonation increased polyDADMAC's NDMA-FP and DMA release. The strategies for reducing NDMA formation from the polymers may include the avoidance of the conditions favorable to NHCl2 formation and the avoidance of polymer exposure to strong oxidants such as ozone. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Application of processes of advanced oxidation as phenol treatment in industrial residual waters of refinery

    International Nuclear Information System (INIS)

    Forero, Jorge Enrique; Ortiz, Olga Patricia; Rios, Fabian

    2005-01-01

    Although more efficient and economical processes for the treatment of sewage have been developed in recent years, the challenge they are facing-due to the greater knowledge of the effect that pollutants have on the environment, the greater consumption of water because of the development of human and industrial activity and the reduction of fresh water sources indicate that we are far from attaining the final solution. This affirmation specially applies to the pollutants, which are resistant to biological treatment processes, such as most of the aromatic compounds found in sewage of the petrochemical industries. In this document, the processes known as advanced oxidation will be explored. Theses have been reported as having the greatest potential in the treatment of these pollutants. Likewise the results of the application of these technologies with waters typical of the petroleum industry will be reported. These have previously been evaluated with processes of typical ozonization

  8. Application of effect-directed analysis to identify mutagenic nitrogenous disinfection by-products of advanced oxidation drinking water treatment

    NARCIS (Netherlands)

    Vughs, D.; Baken, K.A.; Kolkman, A.; Martijn, A.J.; de Voogt, P.

    Advanced oxidation processes are important barriers for organic micropollutants in (drinking) water treatment. It is however known that medium pressure UV/H2O2 treatment may lead to mutagenicity in the Ames test, which is no longer present after granulated activated carbon (GAC) filtration. Many

  9. COAL CONVERSION WASTEWATER TREATMENT BY CATALYTIC OXIDATION IN SUPERCRITICAL WATER; FINAL

    International Nuclear Information System (INIS)

    Phillip E. Savage

    1999-01-01

    Wastewaters from coal-conversion processes contain phenolic compounds in appreciable concentrations. These compounds need to be removed so that the water can be discharged or re-used. Catalytic oxidation in supercritical water is one potential means of treating coal-conversion wastewaters, and this project examined the reactions of phenol over different heterogeneous oxidation catalysts in supercritical water. More specifically, we examined the oxidation of phenol over a commercial catalyst and over bulk MnO(sub 2), bulk TiO(sub 2), and CuO supported on Al(sub 2) O(sub 3). We used phenol as the model pollutant because it is ubiquitous in coal-conversion wastewaters and there is a large database for non-catalytic supercritical water oxidation (SCWO) with which we can contrast results from catalytic SCWO. The overall objective of this research project is to obtain the reaction engineering information required to evaluate the utility of catalytic supercritical water oxidation for treating wastes arising from coal conversion processes. All four materials were active for catalytic supercritical water oxidation. Indeed, all four materials produced phenol conversions and CO(sub 2) yields in excess of those obtained from purely homogeneous, uncatalyzed oxidation reactions. The commercial catalyst was so active that we could not reliably measure reaction rates that were not limited by pore diffusion. Therefore, we performed experiments with bulk transition metal oxides. The bulk MnO(sub 2) and TiO(sub 2) catalysts enhance both the phenol disappearance and CO(sub 2) formation rates during SCWO. MnO(sub 2) does not affect the selectivity to CO(sub 2), or to the phenol dimers at a given phenol conversion. However, the selectivities to CO(sub 2) are increased and the selectivities to phenol dimers are decreased in the presence of TiO(sub 2) , which are desirable trends for a catalytic SCWO process. The role of the catalyst appears to be accelerating the rate of formation of

  10. Oxidative treatments used to make water potable; Tratamientos oxidativos en la potabilizacion del agua

    Energy Technology Data Exchange (ETDEWEB)

    Gracia, R.; Cortes, S.; Sarasa, J.; Ormad, P.; Ovelleiro, J. L. [Universidad de Zaragoza (Spain)

    1999-08-01

    It is studied with pre-ozonation replacing pre-chlorination during drinking-water treatment for improving the water quality since the discovery of potentially harmful chlorination by products such as trihalomethanes (THM). Raw Ebro river (Spain) water is ozonated in the presence of titanium dioxide (TiO{sub 2}) supported on alumina as a catalyst and later chlorinated. It is shown that using this catalyst during ozonation of the natural water allowed reductions in organic matter and therefore in THM formation. Characterization of the organic compounds resulting from oxidation techniques was made by concentrating the sample through liquid-liquid extraction, along with the gas chromatography/mass spectrometry (GC/MS). THMs were measured by an head space connected to a gas chromatograph equipped with an electron capture detector (GC/ECD). (Author) 12 refs.

  11. Progress of Nanocomposite Membranes for Water Treatment

    Directory of Open Access Journals (Sweden)

    Claudia Ursino

    2018-04-01

    Full Text Available The use of membrane-based technologies has been applied for water treatment applications; however, the limitations of conventional polymeric membranes have led to the addition of inorganic fillers to enhance their performance. In recent years, nanocomposite membranes have greatly attracted the attention of scientists for water treatment applications such as wastewater treatment, water purification, removal of microorganisms, chemical compounds, heavy metals, etc. The incorporation of different nanofillers, such as carbon nanotubes, zinc oxide, graphene oxide, silver and copper nanoparticles, titanium dioxide, 2D materials, and some other novel nano-scale materials into polymeric membranes have provided great advances, e.g., enhancing on hydrophilicity, suppressing the accumulation of pollutants and foulants, enhancing rejection efficiencies and improving mechanical properties and thermal stabilities. Thereby, the aim of this work is to provide up-to-date information related to those novel nanocomposite membranes and their contribution for water treatment applications.

  12. Progress of Nanocomposite Membranes for Water Treatment.

    Science.gov (United States)

    Ursino, Claudia; Castro-Muñoz, Roberto; Drioli, Enrico; Gzara, Lassaad; Albeirutty, Mohammad H; Figoli, Alberto

    2018-04-03

    The use of membrane-based technologies has been applied for water treatment applications; however, the limitations of conventional polymeric membranes have led to the addition of inorganic fillers to enhance their performance. In recent years, nanocomposite membranes have greatly attracted the attention of scientists for water treatment applications such as wastewater treatment, water purification, removal of microorganisms, chemical compounds, heavy metals, etc. The incorporation of different nanofillers, such as carbon nanotubes, zinc oxide, graphene oxide, silver and copper nanoparticles, titanium dioxide, 2D materials, and some other novel nano-scale materials into polymeric membranes have provided great advances, e.g., enhancing on hydrophilicity, suppressing the accumulation of pollutants and foulants, enhancing rejection efficiencies and improving mechanical properties and thermal stabilities. Thereby, the aim of this work is to provide up-to-date information related to those novel nanocomposite membranes and their contribution for water treatment applications.

  13. Molecular water oxidation catalysis

    CERN Document Server

    Llobet, Antoni

    2014-01-01

    Photocatalytic water splitting is a promising strategy for capturing energy from the sun by coupling light harvesting and the oxidation of water, in order to create clean hydrogen fuel. Thus a deep knowledge of the water oxidation catalysis field is essential to be able to come up with useful energy conversion devices based on sunlight and water splitting. Molecular Water Oxidation Catalysis: A Key Topic for New Sustainable Energy Conversion Schemes presents a comprehensive and state-of-the-art overview of water oxidation catalysis in homogeneous phase, describing in detail the most importan

  14. Colour and toxic characteristics of metakaolinite–hematite pigment for integrally coloured concrete, prepared from iron oxide recovered from a water treatment plant of an abandoned coal mine

    International Nuclear Information System (INIS)

    Sadasivam, Sivachidambaram; Thomas, Hywel Rhys

    2016-01-01

    A metakaolinite-hematite (KH) red pigment was prepared using an ocherous iron oxide sludge recovered from a water treatment plant of an abandoned coal mine. The KH pigment was prepared by heating the kaolinite and the iron oxide sludge at kaolinite's dehydroxylation temperature. Both the raw sludge and the KH specimen were characterised for their colour properties and toxic characteristics. The KH specimen could serve as a pigment for integrally coloured concrete and offers a potential use for the large volumes of the iron oxide sludge collected from mine water treatment plants. - Graphical abstract: A kaolinite based red pigment was prepared using an ocherous iron oxide sludge recovered from an abandoned coal mine water treatment plant. Display Omitted - Highlights: • A red pigment was prepared by heating a kaolinite and an iron oxide sludge. • The iron oxide and the pigment were characterised for their colour properties. • The red pigment can be a potential element for integrally coloured concrete.

  15. Photocatalytic Oxidation in Drinking Water Treatment Using Hypochlorite and Titanium Dioxide

    NARCIS (Netherlands)

    El-Kalliny, A.S.M.

    2013-01-01

    The main focus of this thesis is to study the advanced oxidation processes (AOPs) of water pollutants via UV/hypochlorite (homogeneous AOPs), and UV solar light/TiO2 (heterogeneous AOPs) in which the highly oxidative hydroxyl radicals (•OH) are produced. These radicals are capable of destructing the

  16. Peracids in water treatment:a critical review

    OpenAIRE

    Luukkonen, T. (Tero); Pehkonen, S. O. (Simo O.)

    2017-01-01

    Abstract Peracids have gained interest in the water treatment over the last few decades. Peracetic acid (CH₃CO₃H) has already become an accepted alternative disinfectant in wastewater disinfection whereas performic acid (CHO₃H) has been studied much less, although it is also already commercially available. Additionally, peracids have been studied for drinking water disinfection, oxidation of aqueous (micro)pollutants, sludge treatment, and ballast water treatment, to name just a few exampl...

  17. Application of Advanced Oxidation Processes in Water Treatment%高级氧化技术在水处理中的应用

    Institute of Scientific and Technical Information of China (English)

    黄洪勋; 孙亚全; 陈明发; 路艳艳

    2012-01-01

    This paper introduces the development and characteristics of advanced oxidation processes. Several advanced oxidation processes, such as chemical oxidation, photocatalytic oxidation, hydrothermal oxidation, high voltage pulsed discharge plasma and ultrasonic, and their application in water treatment are over- viewed. The application of advanced oxidation processes in water treatment will be more mature and be used more widely with the deepening of the research.%介绍了高级氧化技术的发展及其特点,并综述了化学氧化、光催化氧化、水热氧化以及高压脉冲放电等离子体、超声等高级氧化技术及其在水处理中的应用。随着对高级氧化技术不断深入的研究,其在水处理领域的应用将更加成熟并且越来越广泛。

  18. Titania and Zinc Oxide Nanoparticles: Coating with Polydopamine and Encapsulation within Lecithin Liposomes—Water Treatment Analysis by Gel Filtration Chromatography with Fluorescence Detection

    Directory of Open Access Journals (Sweden)

    Xuhao Zhao

    2018-02-01

    Full Text Available The interplay of metal oxide nanoparticles, environmental pollution, and health risks is key to all industrial and drinking water treatment processes. In this work we present a study using gel filtration chromatography for the analytical investigation of metal oxide nanoparticles in water, their coating with polydopamine, and their encapsulation within lecithin liposomes. Polydopamine prevents TiO2 and ZnO nanoparticles from aggregation during chromatographic separation. Lecithin forms liposomes that encapsulate the nanoparticles and carry them through the gel filtration column, producing an increase of peak area for quantitative analysis without any change in retention time to affect qualitative identification. To the best of our knowledge, this is the first report that demonstrates the potential application of lecithin liposomes for cleaning up metal oxide nanoparticles in water treatment. Encapsulation of graphene quantum dots by liposomes would allow for monitoring of nanoparticle-loaded liposomes to ensure their complete removal by membrane ultrafiltration from treated water.

  19. Sea-urchin-like iron oxide nanostructures for water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Uk, E-mail: leeho@kbsi.re.kr [Division of Materials Science, Korea Basic Science Institute, Daejeon 305-333 (Korea, Republic of); Lee, Soon Chang [Department of Fine Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Lee, Young-Chul [Department of Biological Engineering, College of Engineering, Inha University, Incheon 402-751 (Korea, Republic of); Vrtnik, Stane; Kim, Changsoo; Lee, SangGap [Division of Materials Science, Korea Basic Science Institute, Daejeon 305-333 (Korea, Republic of); Lee, Young Boo; Nam, Bora [Jeonju Center, Korea Basic Science Institute, Jeonju 561-756 (Korea, Republic of); Lee, Jae Won [Department of Energy Engineering, Dankook University, Cheonan 330-714 (Korea, Republic of); Park, So Young; Lee, Sang Moon [Division of Materials Science, Korea Basic Science Institute, Daejeon 305-333 (Korea, Republic of); Lee, Jouhahn, E-mail: jouhahn@kbsi.re.kr [Division of Materials Science, Korea Basic Science Institute, Daejeon 305-333 (Korea, Republic of)

    2013-11-15

    Highlights: • The u-MFN were synthesized via a ultrasound irradiation and/or calcinations process. • The u-MFN exhibited excellent adsorption capacities. • The u-MFN also displayed excellent adsorption of organic polluent after recycling. • The u-MFN has the potential to be used as an efficient adsorbent material. -- Abstract: To obtain adsorbents with high capacities for removing heavy metals and organic pollutants capable of quick magnetic separation, we fabricated unique sea-urchin-like magnetic iron oxide (mixed γ-Fe{sub 2}O{sub 3}/Fe{sub 3}O{sub 4} phase) nanostructures (called u-MFN) with large surface areas (94.1 m{sup 2} g{sup −1}) and strong magnetic properties (57.9 emu g{sup −1}) using a simple growth process and investigated their potential applications in water treatment. The u-MFN had excellent removal capabilities for the heavy metals As(V) (39.6 mg g{sup −1}) and Cr(VI) (35.0 mg g{sup −1}) and the organic pollutant Congo red (109.2 mg g{sup −1}). The u-MFN also displays excellent adsorption of Congo red after recycling. Because of its high adsorption capacity, fast adsorption rate, and quick magnetic separation from treated water, the u-MFN developed in the present study is expected to be an efficient magnetic adsorbent for heavy metals and organic pollutants in aqueous solutions.

  20. Sea-urchin-like iron oxide nanostructures for water treatment

    International Nuclear Information System (INIS)

    Lee, Hyun Uk; Lee, Soon Chang; Lee, Young-Chul; Vrtnik, Stane; Kim, Changsoo; Lee, SangGap; Lee, Young Boo; Nam, Bora; Lee, Jae Won; Park, So Young; Lee, Sang Moon; Lee, Jouhahn

    2013-01-01

    Highlights: • The u-MFN were synthesized via a ultrasound irradiation and/or calcinations process. • The u-MFN exhibited excellent adsorption capacities. • The u-MFN also displayed excellent adsorption of organic polluent after recycling. • The u-MFN has the potential to be used as an efficient adsorbent material. -- Abstract: To obtain adsorbents with high capacities for removing heavy metals and organic pollutants capable of quick magnetic separation, we fabricated unique sea-urchin-like magnetic iron oxide (mixed γ-Fe 2 O 3 /Fe 3 O 4 phase) nanostructures (called u-MFN) with large surface areas (94.1 m 2 g −1 ) and strong magnetic properties (57.9 emu g −1 ) using a simple growth process and investigated their potential applications in water treatment. The u-MFN had excellent removal capabilities for the heavy metals As(V) (39.6 mg g −1 ) and Cr(VI) (35.0 mg g −1 ) and the organic pollutant Congo red (109.2 mg g −1 ). The u-MFN also displays excellent adsorption of Congo red after recycling. Because of its high adsorption capacity, fast adsorption rate, and quick magnetic separation from treated water, the u-MFN developed in the present study is expected to be an efficient magnetic adsorbent for heavy metals and organic pollutants in aqueous solutions

  1. Advanced Oxidation Treatment of Drinking Water and Wastewater Using High-energy Electron Beam Irradiation

    Directory of Open Access Journals (Sweden)

    Abbas Behjat

    2007-03-01

    Full Text Available Application of electron beam as a strong oxidation method for disinfection of drinking water and wastewater has been investigated. Drinking water samples were prepared from wells in rock zones in Yazd Province. Wastewater samples were collected from Yazd Wastewater Treatment Plant. Samples were irradiated by 10 MeV electron beam accelerator at Yazd Radiation Processing Center. The irradiation dose range varied from 0.5-5 kGy. Biological parameters and microbial agents such as aerobic mesophiles and coliforms including E. coli count before and after irradiation versus irradiation dose were obtained using MPN method. The data obtained from irradiated water and wastewater were compared with un-irradiated (control samples. The results showed a removal of 90% of all microorganisms at irradiation doses below 5 kGy, suggesting electron beam irradiation as an effective method for disinfection of wastewater.

  2. Petroleum Refinery Effluents Treatment by Advanced Oxidation Process with Methanol

    Energy Technology Data Exchange (ETDEWEB)

    Shoucheng, Wen [Yangtze Univ., HuBei Jingzhou (China)

    2014-02-15

    Petroleum refinery effluents are waste originating from industries primarily engaged in refining crude oil. It is a very complex compound of various oily wastes, water, heavy metals and so on. Conventional processes are unable to effectively remove the chemical oxygen demand (COD) of petroleum refinery effluents. Supercritical water oxidation (SCWO) was proposed to treat petroleum refinery effluents. In this paper, methanol was used to investigate co-oxidative effect of methanol on petroleum refinery effluents treatment. The results indicated that supercritical water oxidation is an effective process for petroleum refinery effluents treatment. Adding methanol caused an increase in COD removal. When reaction temperature is 440 .deg. C, residence time is 20 min, OE is 0.5 and initial COD is 40000 mg/L, and COD removal increases 8.5%.

  3. Petroleum Refinery Effluents Treatment by Advanced Oxidation Process with Methanol

    International Nuclear Information System (INIS)

    Shoucheng, Wen

    2014-01-01

    Petroleum refinery effluents are waste originating from industries primarily engaged in refining crude oil. It is a very complex compound of various oily wastes, water, heavy metals and so on. Conventional processes are unable to effectively remove the chemical oxygen demand (COD) of petroleum refinery effluents. Supercritical water oxidation (SCWO) was proposed to treat petroleum refinery effluents. In this paper, methanol was used to investigate co-oxidative effect of methanol on petroleum refinery effluents treatment. The results indicated that supercritical water oxidation is an effective process for petroleum refinery effluents treatment. Adding methanol caused an increase in COD removal. When reaction temperature is 440 .deg. C, residence time is 20 min, OE is 0.5 and initial COD is 40000 mg/L, and COD removal increases 8.5%

  4. Applications of nano-structured metal oxides for treatment of arsenic in water and for antimicrobial coatings

    Science.gov (United States)

    Sadu, Rakesh Babu

    Dependency of technology has been increasing radically through cellular phones for communication, data storage devices for education, drinking water purifiers for healthiness, antimicrobial-coated textiles for cleanliness, nanomedicines for deadliest diseases, solar cells for natural power, nanorobots for engineering and many more. Nanotechnology develops many unprecedented products and methodologies with its adroitness in this modern scientific world. Syntheses of nanomaterials play a significant role in the development of technology. Solution combustion and hydrothermal syntheses produce many nanomaterials with different structures and pioneering applications. Nanometal oxides, like titania, silver oxide, manganese oxide and iron oxide have their unique applications in engineering, chemistry and biochemistry. Likewise, this study talks about the syntheses and applications of nanomaterials such as magnetic graphene nanoplatelets (M-Gras) decorated with uniformly dispersed NPs, manganese doped titania nanotubes (Mn-TNTs), and silver doped titania nanopartcles (nAg-TNPs) and their polyurethane based polymer nanocomposite coating (nAg-TiO2 /PU). Basically, M-Gras, and Mn-TNTs were applied for the treatment of arsenic contaminated water, and nAg- TiO2/PU applied for antimicrobial coatings on textiles. Adsorption of arsenic over Mn- TNTs, and M-Gras was discussed while considering all the regulations of arsenic contamination in drinking water and oxidation of arsenic over Mn-TNTs also discussed with the possible surface reactions. Silver doped titania and its polyurethane nanocomposite was coated on polyester fabric and examined the coated fabric for bactericidal activity for gram-negative (E. coli) and gram-positive ( S. epidermidis) bacteria. This study elucidates the development of suitable nanomaterials and their applications to treat or rectify the environmental hazards while following the scientific standards and regulations.

  5. Colour and toxic characteristics of metakaolinite-hematite pigment for integrally coloured concrete, prepared from iron oxide recovered from a water treatment plant of an abandoned coal mine

    Science.gov (United States)

    Sadasivam, Sivachidambaram; Thomas, Hywel Rhys

    2016-07-01

    A metakaolinite-hematite (KH) red pigment was prepared using an ocherous iron oxide sludge recovered from a water treatment plant of an abandoned coal mine. The KH pigment was prepared by heating the kaolinite and the iron oxide sludge at kaolinite's dehydroxylation temperature. Both the raw sludge and the KH specimen were characterised for their colour properties and toxic characteristics. The KH specimen could serve as a pigment for integrally coloured concrete and offers a potential use for the large volumes of the iron oxide sludge collected from mine water treatment plants.

  6. Chemical oxidation of unsymmetrical dimethylhydrazine transformation products in water

    NARCIS (Netherlands)

    Abilev, M.; Kenessov, B.N.; Batyrbekova, S.; Grotenhuis, J.T.C.

    2015-01-01

    Oxidation of unsymmetrical dimethylhydrazine (UDMH) during a water treatment has several disadvantages including formation of stable toxic byproducts. Effectiveness of treatment methods in relation to UDMH transformation products is currently poorly studied. This work considers the effectiveness of

  7. Uranium oxidation: characterization of oxides formed by reaction with water

    International Nuclear Information System (INIS)

    Fuller, E.L. Jr.; Smyrl, N.R.; Condon, J.B.; Eager, M.H.

    1983-01-01

    Three different uranium oxide samples have been characterized with respect to the different preparation techniques. Results show that the water reaction with uranium metal occurs cyclically forming laminar layers of oxide which spall off due to the strain at the oxide/metal interface. Single laminae are released if liquid water is present due to the prizing penetration at the reaction zone. The rate of reaction of water with uranium is directly proportional to the amount of adsorbed water on the oxide product. Rapid transport is effected through the open hydrous oxide product. Dehydration of the hydrous oxide irreversibly forms a more inert oxide which cannot be rehydrated to the degree that prevails in the original hydrous product of uranium oxidation with water. 27 figures

  8. High Throughput Plasma Water Treatment

    Science.gov (United States)

    Mujovic, Selman; Foster, John

    2016-10-01

    The troublesome emergence of new classes of micro-pollutants, such as pharmaceuticals and endocrine disruptors, poses challenges for conventional water treatment systems. In an effort to address these contaminants and to support water reuse in drought stricken regions, new technologies must be introduced. The interaction of water with plasma rapidly mineralizes organics by inducing advanced oxidation in addition to other chemical, physical and radiative processes. The primary barrier to the implementation of plasma-based water treatment is process volume scale up. In this work, we investigate a potentially scalable, high throughput plasma water reactor that utilizes a packed bed dielectric barrier-like geometry to maximize the plasma-water interface. Here, the water serves as the dielectric medium. High-speed imaging and emission spectroscopy are used to characterize the reactor discharges. Changes in methylene blue concentration and basic water parameters are mapped as a function of plasma treatment time. Experimental results are compared to electrostatic and plasma chemistry computations, which will provide insight into the reactor's operation so that efficiency can be assessed. Supported by NSF (CBET 1336375).

  9. Water treatment with exceptional virus inactivation using activated carbon modified with silver (Ag) and copper oxide (CuO) nanoparticles.

    Science.gov (United States)

    Shimabuku, Quelen Letícia; Arakawa, Flávia Sayuri; Fernandes Silva, Marcela; Ferri Coldebella, Priscila; Ueda-Nakamura, Tânia; Fagundes-Klen, Márcia Regina; Bergamasco, Rosangela

    2017-08-01

    Continuous flow experiments (450 mL min -1 ) were performed in household filter in order to investigate the removal and/or inactivation of T4 bacteriophage, using granular activated carbon (GAC) modified with silver and/or copper oxide nanoparticles at different concentrations. GAC and modified GAC were characterized by X-ray diffractometry, specific surface area, pore size and volume, pore average diameter, scanning electron microscopy, transmission electron microscopy, zeta potential and atomic absorption spectroscopy. The antiviral activity of the produced porous media was evaluated by passing suspensions of T4 bacteriophage (∼10 5  UFP/mL) through filters. The filtered water was analyzed for the presence of the bacteriophage and the release of silver and copper oxide. The porous media containing silver and copper oxide nanoparticles showed high inactivation capacity, even reaching reductions higher than 3 log. GAC6 (GAC/Ag0.5%Cu1.0%) was effective in the bacteriophage inactivation, reaching 5.53 log reduction. The levels of silver and copper released in filtered water were below the recommended limits (100 ppb for silver and 1000 ppb for copper) in drinking water. From this study, it is possible to conclude that activated carbon modified with silver and copper oxide nanoparticles can be used as a filter for virus removal in the treatment of drinking water.

  10. Nitrite oxidizing bacteria for water treatment in coastal aquaculture system

    Science.gov (United States)

    Noorak, S.; Rakkhiaw, S.; Limjirakhajornt, K.; Uppabullung, A.; Keawtawee, T.; Sangnoi, Y.

    2018-04-01

    This research aimed to isolate and characterize nitrite oxidizing bacteria and to study their capability for water quality improvement. Fourteen strains of bacteria with nitrite-oxidizing character were isolated after 21 days of enrichment in Pep-Beef-NOB medium contained NaNO2. Two strains, SF-1 and SF-5, showed highest nitrite removal rate for 42.42% and 37.2%, respectively. These strains were determined an efficiency of open-system wastewater treatment for 14 days. The results showed that control, SF-1 and SF-5 had remove ammonia from day 1 to day 6. At the end of the study, ammonia was removed by the control, SF-1 and SF-5 for 81.27%, 70.1% and 69.82%, respectively. Nitrite concentration was lowest at day 8 with removal rate of 98.73%, 98.3% and 97.24% from control, SF-1 and SF-5, respectively. However, nitrite concentration in control experiment was increased again at day 11 whereas in SF-1 and SF-5 were increased at day 13. Chemical Oxygen Demand (COD) was decreased by 77.78%, 73.50% and 78.63% in the control, SF-1 and SF-5, respectively. Biological Oxygen Demand (BOD) in the control, SF-1 and SF-5 were reduced by 85.92%, 79.53% and 82.09%, respectively. Based on 16S rRNA gene, SF-1 and SF-5 were identified as Bacillus vietnamensis and B. firmus, respectively.

  11. Field-analysis of potable water quality and ozone efficiency in ozone-assisted biological filtration systems for surface water treatment.

    Science.gov (United States)

    Zanacic, Enisa; Stavrinides, John; McMartin, Dena W

    2016-11-01

    Potable water treatment in small communities is challenging due to a complexity of factors starting with generally poor raw water sources, a smaller tax and consumption base that limit capital and operating funds, and culminating in what is typically a less sophisticated and robust water treatment plant for production and delivery of safe, high quality potable water. The design and optimization of modular ozone-assisted biological filtration systems can address some of these challenges. In surface water treatment, the removal of organic matter (e.g., dissolved organic carbon - DOC), inorganic nutrients and other exposure-related contaminants (e.g., turbidity and dissolved solids) from the raw water source is essential. Thus, a combination of chemical and biological oxidation processes can produce an effective and efficient water treatment plant design that is also affordable and robust. To that end, the ozone-assisted biological filtration water treatment plants in two communities were evaluated to determine the efficacy of oxidation and contaminant removal processes. The results of testing for in-field system performance indicate that plant performance is particularly negatively impacted by high alkalinity, high organics loading, and turbidity. Both bicarbonate and carbonate alkalinity were observed to impede ozone contact and interaction with DOC, resulting in lower than anticipated DOC oxidation efficiency and bioavailability. The ozone dosage at both water treatment plants must be calculated on a more routine basis to better reflect both the raw water DOC concentration and presence of alkalinities to ensure maximized organics oxidation and minimization of trihalomethanes production. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

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

    Science.gov (United States)

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

    2015-12-01

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

  13. Treatment of Radioactive Organic Wastes by an Electrochemical Oxidation

    International Nuclear Information System (INIS)

    Kim, K.H.; Ryue, Y.G.; Kwak, K.K.; Hong, K.P.; Kim, D.H.

    2007-01-01

    A waste treatment system by using an electrochemical oxidation (MEO, Mediated Electrochemical Oxidation) was installed at KAERI (Korea Atomic Energy Research Institute) for the treatment of radioactive organic wastes, especially EDTA (Ethylene Diamine Tetraacetic Acid) generated during the decontamination activity of nuclear installations. A cerium and silver mediated electrochemical oxidation technique method has been developed as an alternative for an incineration process. An experiment to evaluate the applicability of the above two processes and to establish the conditions to operate the pilot-scale system has been carried out by changing the concentration of the catalyst and EDTA, the operational current density, the operating temperature, and the electrolyte concentration. As for the results, silver mediated oxidation was more effective in destructing the EDTA wastes than the cerium mediated oxidation process. For a constant volume of the EDTA wastes, the treatment time for the cerium-mediated oxidation was 9 hours and its conversion ratio of EDTA to water and CO 2 was 90.2 % at 80 deg. C, 10 A, but the treatment time for the silver-mediated oxidation was 3 hours and its conversion ratio was 89.2 % at 30 deg. C, 10 A. (authors)

  14. Nanostructured manganese oxides as highly active water oxidation catalysts: a boost from manganese precursor chemistry.

    Science.gov (United States)

    Menezes, Prashanth W; Indra, Arindam; Littlewood, Patrick; Schwarze, Michael; Göbel, Caren; Schomäcker, Reinhard; Driess, Matthias

    2014-08-01

    We present a facile synthesis of bioinspired manganese oxides for chemical and photocatalytic water oxidation, starting from a reliable and versatile manganese(II) oxalate single-source precursor (SSP) accessible through an inverse micellar molecular approach. Strikingly, thermal decomposition of the latter precursor in various environments (air, nitrogen, and vacuum) led to the three different mineral phases of bixbyite (Mn2 O3 ), hausmannite (Mn3 O4 ), and manganosite (MnO). Initial chemical water oxidation experiments using ceric ammonium nitrate (CAN) gave the maximum catalytic activity for Mn2 O3 and MnO whereas Mn3 O4 had a limited activity. The substantial increase in the catalytic activity of MnO in chemical water oxidation was demonstrated by the fact that a phase transformation occurs at the surface from nanocrystalline MnO into an amorphous MnOx (1treatment with CAN, which acted as an oxidizing agent. Photocatalytic water oxidation in the presence of [Ru(bpy)3 ](2+) (bpy=2,2'-bipyridine) as a sensitizer and peroxodisulfate as an electron acceptor was carried out for all three manganese oxides including the newly formed amorphous MnOx . Both Mn2 O3 and the amorphous MnOx exhibit tremendous enhancement in oxygen evolution during photocatalysis and are much higher in comparison to so far known bioinspired manganese oxides and calcium-manganese oxides. Also, for the first time, a new approach for the representation of activities of water oxidation catalysts has been proposed by determining the amount of accessible manganese centers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Accelerated evaporation of water on graphene oxide.

    Science.gov (United States)

    Wan, Rongzheng; Shi, Guosheng

    2017-03-29

    Using molecular dynamics simulations, we show that the evaporation of nanoscale volumes of water on patterned graphene oxide is faster than that on homogeneous graphene oxide. The evaporation rate of water is insensitive to variation in the oxidation degree of the oxidized regions, so long as the water film is only distributed on the oxidized regions. The evaporation rate drops when the water film spreads onto the unoxidized regions. Further analysis showed that varying the oxidation degree observably changed the interaction between the outmost water molecules and the solid surface, but the total interaction for the outmost water molecules only changed a very limited amount due to the correspondingly regulated water-water interaction when the water film is only distributed on the oxidized regions. When the oxidation degree is too low and some unoxidized regions are also covered by the water film, the thickness of the water film decreases, which extends the lifetime of the hydrogen bonds for the outmost water molecules and lowers the evaporation rate of the water. The insensitivity of water evaporation to the oxidation degree indicates that we only need to control the scale of the unoxidized and oxidized regions for graphene oxide to regulate the evaporation of nanoscale volumes of water.

  16. ARSENIC MOBILITY FROM IRON OXIDE SOLIDS PRODUCED DURING WATER TREATMENT

    Science.gov (United States)

    The Arsenic Rule under the Safe Drinking Water Act will require certain drinking water suppliers to add to or modify their existing treatment in order to comply with the new 10 ppb arsenic standard. One of the treatment options is co-precipitation of arsenic with iron. This tre...

  17. Post-treatment of reclaimed waste water based on an electrochemical advanced oxidation process

    Science.gov (United States)

    Verostko, Charles E.; Murphy, Oliver J.; Hitchens, G. D.; Salinas, Carlos E.; Rogers, Tom D.

    1992-01-01

    The purification of reclaimed water is essential to water reclamation technology life-support systems in lunar/Mars habitats. An electrochemical UV reactor is being developed which generates oxidants, operates at low temperatures, and requires no chemical expendables. The reactor is the basis for an advanced oxidation process in which electrochemically generated ozone and hydrogen peroxide are used in combination with ultraviolet light irradiation to produce hydroxyl radicals. Results from this process are presented which demonstrate concept feasibility for removal of organic impurities and disinfection of water for potable and hygiene reuse. Power, size requirements, Faradaic efficiency, and process reaction kinetics are discussed. At the completion of this development effort the reactor system will be installed in JSC's regenerative water recovery test facility for evaluation to compare this technique with other candidate processes.

  18. Study on treatment of distilled ammonia waste water from coke plant with activated carbon-NaClO catalytic oxidation method

    Energy Technology Data Exchange (ETDEWEB)

    Luo, D.; Yi, P.; Liu, J.; Chen, A. [Xiangtan Polytechnic University, Xiangtan (China). Dept. of Chemical Enginering

    2001-12-01

    Catalytic oxidation method for the treatment of distilled ammonia waste water from coke plant was investigated using activated carbon as catalyst and NaClO as oxidant. The influences of main factors, such as NaClO, activated carbon, pH and reactionary time were discussed. The results showed that under the conditions of 25{degree}C, NaClO/CODO=1.5, carbon/NaClO=0.6 and pH=3.0, the reaction completed within 120 minutes with 99.5% of phenol removal and 75.8% of COD removal when the distilled ammonia waste water from coke plant which containing phenol 510 mg/L and CODO 8420 mg/L was treated. 13 refs., 4 figs.

  19. Studies on urine treatment by biological purification using Azolla and UV photocatalytic oxidation

    Science.gov (United States)

    Liu, Xiaofeng; Chen, Min; Bian, Zuliang; Liu, Chung-Chu

    The amount of water consumed in space station operations is very large. In order to reduce the amount of water which must be resupplied from Earth, the space station needs to resolve the problems of water supply. For this reason, the recovery, regeneration and utilization of urine of astronauts are of key importance. Many investigations on this subject have been reported. Our research is based on biological absorption and, purification using UV photocatalytic oxidation techniques to achieve comprehensive treatment for urine. In the treatment apparatus we created, the urine solution is used as part of the nutrient solution for the biological components in our bioregenerative life support system. After being absorbed, the nutrients from the urine were then decomposed, metabolized and purified which creates a favorable condition for the follow-up oxidation treatment by UV photocatalytic oxidation. After these two processes, the treated urine solution reached Chinese national standards for drinking water quality (GB5749-1985).

  20. Development of electrospun nanofiber composites for pointof-use water treatment

    Science.gov (United States)

    Peter, Katherine T.

    A range of chemical pollutants now contaminate drinking water sources and present a public health concern, including organic compounds, such as pharmaceuticals and pesticides, and both metalloids and heavy metals, such as arsenic and lead. Metalloids and heavy metals have been detected in private drinking water wells, which do not fall under federal drinking water regulations, as well as in urban tap water, due to the introduction of contamination to the drinking water distribution system. Further, many so-called "emerging organic contaminants," which are present in drinking water sources at detectable levels but have unknown long-term health implications, do not fall under federal drinking water regulations. To protect the health of consumers, drinking water treatment at the point-of-use (POU) (i.e., the tap) is essential. Next-generation POU treatment technologies must require minimal energy inputs, be simple enough to permit broad application among different users, and be easily adaptable for removal of a wide range of pollutants. Nanomaterials, such as carbon nanotubes and iron oxide nanoparticles, are ideal candidates for next-generation drinking water treatment, as they exhibit unique, high reactivity and necessitate small treatment units. However, concerns regarding water pressure requirements and nanomaterial release into the treated supply limit their application in traditional reactor designs. To bridge the gap between potential and practical application of nanomaterials, this study utilizes electrospinning to fabricate composite nanofiber filters that effectively deploy nanomaterials in drinking water treatment. In electrospinning, a high voltage draws a polymer precursor solution (which can contain nanomaterial additives, in the case of nanocomposites) from a needle to deposit a non-woven nanofiber filter on a collector surface. Using electrospinning, we develop an optimized, macroporous carbon nanotube-carbon nanofiber composite that utilizes the

  1. Nitrous oxide emissions from wastewater treatment processes

    Science.gov (United States)

    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

  2. Feasibility of electrochemical oxidation process for treatment of saline wastewater

    Directory of Open Access Journals (Sweden)

    Kavoos Dindarloo

    2015-09-01

    Full Text Available Background: High concentration of salt makes biological treatment impossible due to bacterial plasmolysis. The present research studies the process of electrochemical oxidation efficiency and optimal levels as important factors affecting pH, salt concentration, reaction time and applied voltage. Methods: The sample included graphite electrodes with specifications of 2.5 cm diameter and 15 cm height using a reactor with an optimum capacity of 1 L. Sixty samples were obtained with the aid of the experiments carried out in triplicates for each factor at 5 different levels. The entire experiments were performed based on standard methods for water and waste water treatments. Results: Analysis of variance carried out on effect of pH, salt concentration, reaction time and flow intensity in elimination of chemical oxygen demand (COD showed that they are significant factors affecting this process and reduce COD with a coefficient interval of 95% and test power of 80%. Scheffe test showed that at optimal level, a reaction time of 1 hour, 10 g/L concentration, pH = 9 and 15 V electrical potential difference were obtained. Conclusion: Waste waters containing salt may contribute to the electro-oxidation process due to its cations and anions. Therefore, the process of electrochemical oxidation with graphite electrodes could be a proper strategy for the treatment of saline wastewater where biological treatment is not possible.

  3. Supercritical water oxidation test bed effluent treatment study

    International Nuclear Information System (INIS)

    Barnes, C.M.

    1994-04-01

    This report presents effluent treatment options for a 50 h Supercritical Water Test Unit. Effluent compositions are calculated for eight simulated waste streams, using different assumed cases. Variations in effluent composition with different reactor designs and operating schemes are discussed. Requirements for final effluent compositions are briefly reviewed. A comparison is made of two general schemes. The first is one in which the effluent is cooled and effluent treatment is primarily done in the liquid phase. In the second scheme, most treatment is performed with the effluent in the gas phase. Several unit operations are also discussed, including neutralization, mercury removal, and evaporation

  4. Implementation of advanced electrochemical oxidation for radiochemical concentrate treatment

    International Nuclear Information System (INIS)

    Velin, Anna; Bengtsson, Bernt; Lundblad, Magnus

    2012-09-01

    Water treatments in Nuclear Power Plants include ion exchange, evaporation and mechanical filtration techniques. These technologies are used to control the chemical release and to treat coolant in light water reactor types from chemicals and most importantly, from radioactive nuclides. Most of the conventional methods are efficient, but at the same time producing aqueous concentrates with high organic load. Before final storage, the level of organic content of those concentrates must be reduced. Advanced electrochemical oxidation with Boron Doped Diamond (BDD) electrodes are being investigated in laboratory- and pilot scale for treatment of dilute and concentrated aqueous waste streams at Vattenfall-Ringhals NPP. BDD anodes and cathodes are having high over potential against water electrolysis, and therefore well suitable for oxidation of organics. Dilute wastewater, such as laundry water, which has an initial COD level of around 500 mg/l, was reduced to a level of < 20 mg/l in the laboratory. Evaporator concentrates, with a TS content of 3% and pH of 7-8, were treated in pilot scale of 800 liters, working in batch operation mode, at temperatures between 25-50 deg. C. Initial COD levels between 2500 and 8000 mg/l in concentrate was reduced to < 100 mg/l at the first tests and later to < 300 mg/l. The advanced electrochemical oxidation is proven to be a promising technique for radioactive concentrate treatment. Long-term operation is still ongoing to evaluate the performance of the electrodes, cell components and overall process efficiency. (authors)

  5. Citrus processing waste water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Hawash, S; Hafez, A J; El-Diwani, G

    1988-02-01

    The process utilizes biological treatment to decompose organic matter and decreases the COD to a value of 230 ppm, using 161 of air per 1 of treated waste water for a contact time of 2.5 h. Ozone is used subsequently for further purification of the waste water by destroying refractory organics. This reduces the COD to a value of 40 ppm, and consequently also lowers the BOD. Ozone also effectively removed the yellow-brown colour due to humic substances in dissolved or colloidal form; their oxidation leaves the water sparkling. Iron and manganese are also eliminated.

  6. Rational design of nanomaterials for water treatment

    KAUST Repository

    Li, Renyuan

    2015-08-26

    The ever-increasing human demand for safe and clean water is gradually pushing conventional water treatment technologies to their limits and it is now a popular perception that the solutions to the existing and future water challenges will highly hinge upon the further development of nanomaterial sciences. The concept of rational design emphasizes ‘design-for-purpose’ and it necessitates a scientifically clear problem definition to initiate the nanomaterial design. The field of rational design of nanomaterials for water treatment has experienced a significant growth in the past decade and is poised to make its contribution in creating advanced next-generation water treatment technologies in the years to come. Within the water treatment context, this review offers a comprehensive and in-depth overview of the latest progress of the rational design, synthesis and applications of nanomaterials in adsorption, chemical oxidation and reduction reactions, membrane-based separation, oil/water separation, and synergistic multifunctional all-in-one nanomaterials/nanodevices. Special attention is paid on chemical concepts of the nanomaterial designs throughout the review.

  7. Present municipal water treatment and potential removal methods

    International Nuclear Information System (INIS)

    Lee, S.Y.; White, S.K.; Bondietti, E.A.

    1982-01-01

    Uranium analyses of raw water, intermediate stage, and treated water samples from 20 municipal water treatment plants indicated that the present treatment practices were not effective in removing uranium from raw waters when the influent concentration was in the range of 0.1 to 16 μg/L uranium. Laboratory batch tests revealed that the water softening and coagulant chemicals commonly used were able to remove more than 90% of the dissolved uranium ( < 100 μg/L) in waters if an optimum pH and dosage were provided. Absorbents, titanium oxide and activated charcoal, were also effective in uranium removal under specific conditions. Strong base anion exchange resin was the most efficient uranium adsorbent, and an anion exchange column is a recommended option for the treatment of private well waters containing uranium at higher than desirable levels

  8. Waste Water Management and Infectious Disease. Part II: Impact of Waste Water Treatment

    Science.gov (United States)

    Cooper, Robert C.

    1975-01-01

    The ability of various treatment processes, such as oxidation ponds, chemical coagulation and filtration, and the soil mantle, to remove the agents of infectious disease found in waste water is discussed. The literature concerning the efficiency of removal of these organisms by various treatment processes is reviewed. (BT)

  9. Review of iron oxides for water treatment

    International Nuclear Information System (INIS)

    Navratil, J. D.

    2001-01-01

    Many processes have utilized iron oxides for the treatment of liquid wastes containing radioactive and hazardous metals. These processes have included adsorption, precipitation and other chemical and physical techniques. For example, a radioactive wastewater precipitation process includes addition of a ferric hydroxide floc to scavenge radioactive contaminants, such as americium, plutonium and uranium. Some adsorption processes for wastewater treatment have utilized ferrites and a variety of iron containing minerals. Various ferrites and natural magnetite were used in batch modes for actinide and heavy metal removal from wastewater. Supported magnetite was also used in a column mode, and in the presence of an external magnetic field, enhanced capacity was found for removal of plutonium and americium from wastewater. These observations were explained by a nano-level high gradient magnetic separation effect, as americium, plutonium and other hydrolytic metals are known to form colloidal particles at elevated pHs. Recent modeling work supports this assumption and shows that the smaller the magnetite particle the larger the induced magnetic field around the particle from the external field. Other recent studies have demonstrated the magnetic enhanced removal of arsenic, cobalt and iron from simulated groundwater. (author)

  10. Metal release behavior of surface oxidized stainless steels into flowing high temperature pure water

    International Nuclear Information System (INIS)

    Fujiwara, Kazuo; Tomari, Haruo; Nakayama, Takenori; Shimogori, Kazutoshi; Ishigure, Kenkichi; Matsuura, Chihiro; Fujita, Norihiko; Ono, Shoichi.

    1987-01-01

    In order to clarify the effect of oxidation treatment of Type 304 SS on the inhibition of metal release into high temperature pure water, metal release rate of individual alloying element into flowing deionized water containing 50 ppb dissolved oxygen was measured as the function of exposure time on representative specimens oxidized in air and steam. The behavior of metal release was also discussed in relation to the structure of surface films. Among the alloying elements the amount of Fe ion, Cr ion and Fe crud in high temperature pure water tended to saturate with the exposure time and that of Ni ion and Co ion tended to increase monotonously with the exposure time for all specimens tested. And the treatment of steam-oxidation was the most effective to decrease the metal release of alloying elements and the treatment by air-oxidation also decreased the metal release. These tendencies were confirmed to correlate well with the structure of the surface films as it was in the results in the static autoclave test. (author)

  11. WATER MICROPOLLUTANTS: CLASSIFICATION AND TREATMENT TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    Yolanda Patiño

    2014-06-01

    Full Text Available This article reviews the different kinds of emerging contaminants, their origin and use, and their presence in the Spanish waters, both in surface and groundwater. Micropollutants are compounds of different origin and chemical nature which had been unnoticed (due to their low concentration and don’t have specific regulation. They are divided into six major groups, and many of them behave as endocrine disruptors causing large negative effects on human health and environment. They are in waters because the waste water treatment plants are not designed for their removal, so they are being discharged. Different alternatives for their removal are discussed - physico- chemical, biological and hybrid treatment technologies -. Among the physicochemical process, the advance oxidation processes (AOPs are very promising.

  12. Formation and fates of nitrosamines and their formation potentials from a surface water source to drinking water treatment plants in Southern Taiwan.

    Science.gov (United States)

    Chen, Wei-Hsiang; Wang, Chung-Ya; Huang, Tsung-Hsien

    2016-10-01

    Nitrosamines are toxic and emerging disinfection byproducts. In this study, three drinking water treatment plants (DWTPs) in southern Taiwan treating the same source water in Gaoping River with comparable technologies were selected. The objective was to evaluate the formation and fates of six nitrosamines and their formation potentials (FPs) from a surface water source to drinking water. Albeit decreased further downstream in the river, four nitrosamine-FPs were observed in the source water due to anthropogenic pollution in the upstream areas. In the DWTPs, nitrosamines were formed and NDMA was the main species. While high organic carbon concentrations indicated elevated nitrosamine-FPs in the source water, NDMA formation in the DWTPs was more positively associated with reductions of water parameters that quantify organic matters with double bonded ring structures. Although precursor removal via pre-oxidation is a viable approach to limit nitrosamine formation during post-disinfection, this study clearly indicates that a great portion of NDMA in treated water has been formed in the 1st oxidation step of drinking water treatment. The pre-oxidation simulations in the lab demonstrated the impact of pre-chlorination on nitrosamine formation. Given the limited removal in conventional treatment processes, avoiding nitrosamine-FPs in sources and/or nitrosamine formation during pre-oxidation become important issues to control the threats of nitrosamines in drinking water. Under current circumstance in which pre-oxidation is widely used to optimize the treatment effectiveness in many DWTPs, its adverse effect by forming nitrosamines needs to be carefully minimized and using technologies other than pre-chlorination (e.g., pre-ozonation) may be considered. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Ion exchange resins destruction in a stirred supercritical water oxidation reactor

    International Nuclear Information System (INIS)

    Leybros, A.; Roubaud, A.; Guichardon, P.; Boutin, O.

    2010-01-01

    Spent ion exchange resins (IERs) are radioactive process wastes for which there is no satisfactory industrial treatment. Supercritical water oxidation offers a viable treatment alternative to destroy the organic structure of resins, used to remove radioactivity. Up to now, studies carried out in supercritical water for IER destruction showed that degradation rates higher than 99% are difficult to obtain even using a catalyst or a large oxidant excess. In this study, a co-fuel, isopropanol, has been used in order to improve degradation rates by initiating the oxidation reaction and increasing temperature of the reaction medium. Concentrations up to 20 wt% were tested for anionic and cationic resins. Total organic carbon reduction rates higher than 99% were obtained from this process, without the use of a catalyst. The influence of operating parameters such as IERs feed concentration, nature and counterions of exchanged IERs were also studied. (authors)

  14. Electrochemical Oxidation of PAHs in Water from Harbor Sediment Purification

    DEFF Research Database (Denmark)

    Muff, Jens; Søgaard, Erik Gydesen

    2010-01-01

    generated oxidant solution with a free chlorine concentration of 2 gL-1. Both strategies resulted in a successful degradation of 5 PAHs to fulfil the discharge limit on 0.010 µgL-1. The intermixing-with-oxidant approach can also be applied as a method to address the actual sediment matrix....... of the discharge water addressing primarily polycyclic aromatic hydrocarbons (PAHs). PAHs are by-products of incomplete combustion of organic materials with recalcitrant and strong mutagenic/carcinogenic properties, due to their benzene analogue structures. PAHs are hydrophobic compounds and their persistence...... evidence for the importance of the indirect oxidation mechanism in the degradation of the PAHs. The proof-of-concept study was conducted both by a direct treatment approach and an intermixing-with-oxidant approach, where the contaminated water was intermixed in different ratios with an electrochemically...

  15. Microcystis aeruginosa-laden water treatment using enhanced coagulation by persulfate/Fe(II), ozone and permanganate: Comparison of the simultaneous and successive oxidant dosing strategy.

    Science.gov (United States)

    Liu, Bin; Qu, Fangshu; Chen, Wei; Liang, Heng; Wang, Tianyu; Cheng, Xiaoxiang; Yu, Huarong; Li, Guibai; Van der Bruggen, Bart

    2017-11-15

    In this study, the application of enhanced coagulation with persulfate/Fe(II), permanganate and ozone for Microcystis-laden water treatment was investigated. Two oxidant dosage strategies were compared in terms of the organic removal performance: a simultaneous dosing strategy (SiDS) and a successive dosing strategy (SuDS). To optimize the oxidant species, oxidant doses and oxidant dosage strategy, the zeta potential, floc size and dimension fraction, potassium release and organic removal efficiency during the coagulation of algae-laden water were systematically investigated and comprehensively discussed. Ozonation causes most severe cell lysis and reduces organic removal efficiency because it releases intracellular organics. Moreover, ozonation can cause the release of odor compounds such as 2-methylisoborneol (2-MIB) and geosmin (GSM). With increasing doses, the performance of pollutant removal by coagulation enhanced by persulfate/Fe(II) or permanganate did not noticeably improve, which suggests that a low dosage of persulfate/Fe(II) and permanganate is the optimal strategy to enhance coagulation of Microcystis-laden water. The SiDS performs better than the SuDS because more Microcystis cell lysis occurs and less DOC is removed when oxidants are added before the coagulants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Kinetics and mechanism for degradation of dichlorvos by permanganate in drinking water treatment.

    Science.gov (United States)

    Liu, Chao; Qiang, Zhimin; Adams, Craig; Tian, Fang; Zhang, Tao

    2009-08-01

    The degradation kinetics and mechanism of dichlorvos by permanganate during drinking water treatment were investigated. The reaction of dichlorvos with permanganate was of second-order overall with negligible pH dependence and an activation energy of 29.5 kJ x mol(-1). At pH 7.0 and 25 degrees C, the rate constant was 25.2+/-0.4M(-1)s(-1). Dichlorvos was first degraded to trimethyl phosphate (TMP) and dimethyl phosphate (DMP) simultaneously which approximately accounted for or=95% with respect to phosphorus mass, respectively. Further oxidation of DMP generated a final byproduct, monomethyl phosphate (MMP). MMP was for the first time identified as a major byproduct in chemical oxidation of dichlorvos. The kinetic model based on degradation mechanism and determined reaction rate constants allowed us to predict the evolution of dichlorvos and its byproduct concentrations during permanganate pre-oxidation process at water treatment plants. These results suggest that even though the dichlorvos concentration in surface water complies with the surface water quality standards of China (50 microg L(-1)), its concentration after conventional water treatment will most probably exceed the drinking water quality standards (1 microg L(-1)). Moreover, luminescent bacteria test shows that the acute toxicity of dichlorvos solution evidently increased after permanganate oxidation.

  17. Synthesis of Ceria Zirconia Oxides using Solvothermal Treatment

    Directory of Open Access Journals (Sweden)

    Machmudah Siti

    2018-01-01

    Full Text Available Ceria oxide (CeO2 is widely used as catalyst with high oxygen storage capacity at low temperature. The addition of zirconia oxide (ZrO2 to CeO2 can enhance oxygen storage capacity as well as thermal stability. In this work, ceria zirconia oxides has been synthesized via a low temperature solvothermal treatment in order to produce ceria zirconia oxides composite with high oxygen storage capacity as electrolyte of solid oxide fuel cells (SOFC. Under solvothermal conditions, solvent may control the direction of crystal growth, morphology, particle size and size distribution, because of the controllability of thermodynamics and transport properties by pressure and temperature. Water, mixed of water and ethanol (70/30 vol/vol, and mixed of water and ethylene glycol (70/30 vol/vol were used as solvent, while Ce(NO33 and ZrO(NO32 with 0.06 M concentration were used as precursor. The experiments were conducted at temperature of 150 °C and pressure for 2 h in a Teflon-lined autoclave of 100 mL volume. The synthesized products were dried at 60 °C for 6 and 12 h and then calcined at 900 °C for 6 h. The particle products were characterized using SEM, XRD, TG/DTA, and Potentiostat. The results showed that the morphology of particles formed were affected by the solvent. Solid plate shaped particles were produced in water, and tend to be pore with the addition of ethylene glycol. The addition of ethanol decreased the size of particles with sphere shaped. The XRD pattern indicated that ceria-zirconia oxides particles are uniformly distributed in the structure to form a homogeneous solid solution. Based on the electrochemical analysis, ceria zirconia oxides produced via solvothermal synthesis had high conductivity ion of 0.5594 S/cm, which is higher than minimum conductivity ion requirement of 0.01 S/cm for SOFC electrolyte. It indicated that ceria zirconia oxides produced via solvothermal synthesis is suitable for SOFC electrolyte.

  18. Evaluation of tubular reactor designs for supercritical water oxidation of U.S. Department of Energy mixed waste

    International Nuclear Information System (INIS)

    Barnes, C.M.

    1994-12-01

    Supercritical water oxidation (SCWO) is an emerging technology for industrial waste treatment and is being developed for treatment of the US Department of Energy (DOE) mixed hazardous and radioactive wastes. In the SCWO process, wastes containing organic material are oxidized in the presence of water at conditions of temperature and pressure above the critical point of water, 374 C and 22.1 MPa. DOE mixed wastes consist of a broad spectrum of liquids, sludges, and solids containing a wide variety of organic components plus inorganic components including radionuclides. This report is a review and evaluation of tubular reactor designs for supercritical water oxidation of US Department of Energy mixed waste. Tubular reactors are evaluated against requirements for treatment of US Department of Energy mixed waste. Requirements that play major roles in the evaluation include achieving acceptable corrosion, deposition, and heat removal rates. A general evaluation is made of tubular reactors and specific reactors are discussed. Based on the evaluations, recommendations are made regarding continued development of supercritical water oxidation reactors for US Department of Energy mixed waste

  19. Photocatalytic Water Treatment by Titanium Dioxide: Recent Updates

    Directory of Open Access Journals (Sweden)

    Manoj A. Lazar

    2012-12-01

    Full Text Available Photocatalytic water treatment using nanocrystalline titanium dioxide (NTO is a well-known advanced oxidation process (AOP for environmental remediation. With the in situ generation of electron-hole pairs upon irradiation with light, NTO can mineralize a wide range of organic compounds into harmless end products such as carbon dioxide, water, and inorganic ions. Photocatalytic degradation kinetics of pollutants by NTO is a topic of debate and the mostly reporting Langmuir-Hinshelwood kinetics must accompanied with proper experimental evidences. Different NTO morphologies or surface treatments on NTO can increase the photocatalytic efficiency in degradation reactions. Wisely designed photocatalytic reactors can decrease energy consumption or can avoid post-separation stages in photocatalytic water treatment processes. Doping NTO with metals or non-metals can reduce the band gap of the doped catalyst, enabling light absorption in the visible region. Coupling NTO photocatalysis with other water-treatment technologies can be more beneficial, especially in large-scale treatments. This review describes recent developments in the field of photocatalytic water treatment using NTO.

  20. Toxicity assessment of the water used for human consumption from the Cameron/Tuba City abandoned uranium mining area prior/after the combined electrochemical treatment/advanced oxidation.

    Science.gov (United States)

    Gajski, Goran; Oreščanin, Višnja; Gerić, Marko; Kollar, Robert; Lovrenčić Mikelić, Ivanka; Garaj-Vrhovac, Vera

    2015-01-01

    The purpose of this work was detailed physicochemical, radiological, and toxicological characterization of the composite sample of water intended for human consumption in the Cameron/Tuba City abandoned uranium mining area before and after a combined electrochemical/advanced oxidation treatment. Toxicological characterization was conducted on human lymphocytes using a battery of bioassays. On the bases of the tested parameters, it could be concluded that water used for drinking from the tested water sources must be strictly forbidden for human and/or animal consumption since it is extremely cytogenotoxic, with high oxidative stress potential. A combined electrochemical treatment and posttreatment with ozone and UV light decreased the level of all physicochemical and radiological parameters below the regulated values. Consequently, the purified sample was neither cytotoxic nor genotoxic, indicating that the presented method could be used for the improvement of water quality from the sites highly contaminated with the mixture of heavy metals and radionuclides.

  1. Arsenic adsorption in pre-treatment natural zeolite with magnesium oxides

    International Nuclear Information System (INIS)

    Mejia Z, F.; Valenzuela G, J. L.; Aguayo S, S.; Meza F, D.

    2009-01-01

    A methodology was developed to modify a natural zeolite (chabazite) with magnesium oxide in order to remove arsenic (As +5 ) from water for human consumption. It is proposed a magnesium oxide while regarded as an efficient adsorbent for removing metals in water. X-ray diffraction analyses show significant changes in the chabazite due to the presence of oxides and amorphous hydroxides incorporated during the pre-treatment. Experimental design results show an efficiency greater than 90% of As +5 adsorbed in five minutes. The results indicate that the most significant variables affecting the adsorption of As +5 are the initial concentration of As and the solid/liquid ratio. Experimental data fitted better to Freundlich isotherm with a 20.17 mg/g adsorption capability. (Author)

  2. Effect of aging treatment on the in vitro nickel release from porous oxide layers on NiTi

    Energy Technology Data Exchange (ETDEWEB)

    Huan, Z.; Fratila-Apachitei, L.E., E-mail: e.l.fratila-apachitei@tudelft.nl; Apachitei, I.; Duszczyk, J.

    2013-06-01

    Despite the ability of creating porous oxide layers on nickel–titanium alloy (NiTi) surface for biofunctionalization, the use of plasma electrolytic oxidation (PEO) has raised concerns over the possible increased levels of Ni release. Therefore, the primary aim of this study was to investigate the effect of aging in boiling water on Ni release from porous NiTi surfaces that have been formed by the PEO process. Based on different oxidation conditions, e.g. electrolyte composition and electrical parameters, three kinds of oxide layers with various characteristics were prepared on NiTi substrate. The process was followed by aging in boiling water for different durations. The Ni release was assessed by immersion tests in phosphate buffer saline and the Ni concentration was measured using the flame atomic absorption spectrometry. The results showed that aging in boiling water can significantly reduce the Ni release from oxidized porous samples, given that the duration of the treatment is finely adjusted according to the parameters of the as-formed oxide layer. Surface examination of the samples before and after aging in boiling water suggested that such a treatment is non-destructive while improving the corrosion resistance of oxidized samples, as evidenced by potentiodynamic polarization tests. The results of this study indicate that water boiling may be a suitable post-treatment required to minimize Ni release from porous oxides produced on NiTi by PEO for biomedical applications.

  3. OZONE TREATMENT OF SOLUBLE ORGANICS IN PRODUCED WATER

    Energy Technology Data Exchange (ETDEWEB)

    Klasson, KT

    2002-03-14

    This project was an extension of previous research to improve the applicability of ozonation and will help address the petroleum-industry problem of treating produced water containing soluble organics. The goal of this project was to maximize oxidation of hexane-extractable organics during a single-pass operation. The project investigated: (1) oxidant production by electrochemical and sonochemical methods, (2) increasing the mass transfer rate in the reactor by forming microbubbles during ozone injection into the produced water, and (3) using ultraviolet irradiation to enhance the reaction if needed. Several types of methodologies for treatment of soluble organics in synthetic and actual produced waters have been performed. The technologies tested may be categorized as follows: (1) Destruction via sonochemical oxidation at different pH, salt concentration, ultraviolet irradiation, and ferrous iron concentrations. (2) Destruction via ozonation at different pH, salt concentration, hydrogen peroxide concentrations, ultraviolet irradiation, temperature, and reactor configurations.

  4. Water reactivity with mixed oxide (U,Pu)O2 surfaces

    International Nuclear Information System (INIS)

    Gaillard, Jeremy

    2013-01-01

    The interaction of water with actinides oxide surfaces remains poorly understood. The adsorption of water on PuO 2 surface and (U,Pu)O 2 surface leads to hydrogen generation through radiolysis but also surface evolution. The study of water interaction with mixed oxide (U,Pu)O 2 and PuO 2 surfaces requires the implementation of non intrusive techniques. The study of the hydration of CeO 2 surface is used to study the effectiveness of different techniques. The results show that the water adsorption leads to the surface evolution through the formation of a hydroxide superficial layer. The reactivity of water on the surface depends on the calcination temperature of the oxide precursor. The thermal treatment of hydrated surfaces can regenerate the surface. The study on CeO 2 hydration emphasizes the relevancies of these techniques in studying the hydration of surfaces. The hydrogen generation through water radiolysis is studied with an experimental methodology based on constant relative humidity in the radiolysis cell. The hydrogen accumulation is linear for the first hours and then tends to a steady state content. A mechanism of hydrogen consumption is proposed to explain the existence of the steady state of hydrogen content. This mechanism enables to explain also the evolution of the oxide surface during hydrogen generation experiments as shown by the evolution of hydrogen accumulation kinetics. The accumulation kinetics depends on the dose rate, specific surface area and the relative humidity but also on the oxide aging. The plutonium percentage appears to be a crucial parameter in hydrogen accumulation kinetics. (author) [fr

  5. Drainage treatment technology for water pollution prevention

    Energy Technology Data Exchange (ETDEWEB)

    Ebise, Sen' ichi

    1988-03-01

    Drainage is purified either at terminal treatment plants or by septic tanks for sewage. At terminal treatment plants, sewage is purified by activated sludge prosessing or by biological treatment equipment. By the normal activated sludge processing, only 20 - 30 % of nitrogen and phosphur can be removed. To solve this problem, many advanced processing systems have been employed, representative systems being coagulating sedimentation, rapid filtration, recirculating nitro-denitrification, etc. The coagulating sedimentation is a treatment process in which such metallic salt coagulations as aluminum, iron, etc. are injected and mixed with sewage, and then phosphur and the like are sedimented in the form of grains. The rapid filtration requires no large space, and can reliably remove suspended matter. For large scale septic tank processing system, advance treatment processing is supplemented to improve the quality of treated water. Among other systems of sewage purification are oxidized channel, oxidized pond, soil treatment, etc. (2 figs, 2 refs)

  6. Method of producing deuterium-oxide-enriched water

    International Nuclear Information System (INIS)

    Mandel, H.

    1976-01-01

    A method and apparatus for producing deuterium-oxide-enriched water (e.g., as a source of deuterium-rich gas mixtures) are disclosed wherein the multiplicity of individual cooling cycles of a power plant are connected in replenishment cascade so that fresh feed water with a naturally occurring level of deuterium oxide is supplied to replace the vaporization losses, sludge losses and withdrawn portion of water in a first cooling cycle, the withdrawn water being fed as the feed water to the subsequent cooling cycle or stage and serving as the sole feed-water input to the latter. At the end of the replenishment-cascade system, the withdrawn water has a high concentration of deuterium oxide and may serve as a source of water for the production of heavy water or deuterium-enriched gas by conventional methods of removing deuterium oxide or deuterium from the deuterium-oxide-enriched water. Each cooling cycle may form part of a thermal or nuclear power plant in which a turbine is driven by part of the energy and air-cooling of the water takes place in the atmosphere, e.g., in a cooling tower

  7. Removal of cyanobacterial amino acids in water treatment by activated carbon adsorption

    Czech Academy of Sciences Publication Activity Database

    Čermáková, Lenka; Kopecká, Ivana; Pivokonský, Martin; Pivokonská, Lenka; Janda, V.

    2017-01-01

    Roč. 173, č. 1 (2017), s. 330-338 ISSN 1383-5866 Institutional support: RVO:67985874 Keywords : amino acids * activated carbon * adsorption * algal organic matter * water treatment * coagulation * microcystis aeruginosa * peptides/proteins * permanganate pre-oxidation * water treatment Subject RIV: DJ - Water Pollution ; Quality OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 3.359, year: 2016

  8. Removal of antibiotics from surface and distilled water in conventional water treatment processes

    Science.gov (United States)

    Adams, C.; Wang, Y.; Loftin, K.; Meyer, M.

    2002-01-01

    Conventional drinking water treatment processes were evaluated under typical water treatment plant conditions to determine their effectiveness in the removal of seven common antibiotics: carbadox, sulfachlorpyridazine, sulfadimethoxine, sulfamerazine, sulfamethazine, sulfathiazole, and trimethoprim. Experiments were conducted using synthetic solutions prepared by spiking both distilled/ deionized water and Missouri River water with the studied compounds. Sorption on Calgon WPH powdered activated carbon, reverse osmosis, and oxidation with chlorine and ozone under typical plant conditions were all shown to be effective in removing the studied antibiotics. Conversely, coagulation/flocculation/sedimentation with alum and iron salts, excess lime/soda ash softening, ultraviolet irradiation at disinfection dosages, and ion exchange were all relatively ineffective methods of antibiotic removal. This study shows that the studied antibiotics could be effectively removed using processes already in use many water treatment plants. Additional work is needed on by-product formation and the removal of other classes of antibiotics.

  9. An engineered polypeptide around nano-sized manganese-calcium oxide: copying plants for water oxidation.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Ghobadi, Mohadeseh Zarei; Sarvi, Bahram; Haghighi, Behzad

    2015-09-14

    Synthesis of new efficient catalysts inspired by Nature is a key goal in the production of clean fuel. Different compounds based on manganese oxide have been investigated in order to find their water-oxidation activity. Herein, we introduce a novel engineered polypeptide containing tyrosine around nano-sized manganese-calcium oxide, which was shown to be a highly active catalyst toward water oxidation at low overpotential (240 mV), with high turnover frequency of 1.5 × 10(-2) s(-1) at pH = 6.3 in the Mn(III)/Mn(IV) oxidation range. The compound is a novel structural and efficient functional model for the water-oxidizing complex in Photosystem II. A new proposed clever strategy used by Nature in water oxidation is also discussed. The new model of the water-oxidizing complex opens a new perspective for synthesis of efficient water-oxidation catalysts.

  10. Partial oxidation of TiN coating by hydrothermal treatment and ozone treatment to improve its osteoconductivity

    International Nuclear Information System (INIS)

    Shi, Xingling; Xu, Lingli; Le, Thi Bang; Zhou, Guanghong; Zheng, Chuanbo; Tsuru, Kanji; Ishikawa, Kunio

    2016-01-01

    Dental implants made of pure titanium suffer from abrasion and scratch during routine oral hygiene procedures. This results in an irreversible surface damage, facilitates bacteria adhesion and increases risk of peri-implantitis. To overcome these problems, titanium nitride (TiN) coating was introduced to increase surface hardness of pure titanium. However, the osteoconductivity of TiN is considered to be similar or superior to that of titanium and its alloys and therefore surface modification is necessary. In this study, TiN coating prepared through gas nitriding was partially oxidized by hydrothermal (HT) treatment and ozone (O 3 ) treatment in pure water to improve its osteoconductivity. The effects of HT treatment and O 3 treatment on surface properties of TiN were investigated and the osteoconductivity after undergoing treatment was assessed in vitro using osteoblast evaluation. The results showed that the critical temperature for HT treatment was 100 °C since higher temperatures would impair the hardness of TiN coating. By contrast, O 3 treatment was more effective in oxidizing TiN surfaces, improving its wettability while preserving its morphology and hardness. Osteoblast attachment, proliferation, alkaline phosphatase (ALP) expression and mineralization were improved on oxidized specimens, especially on O 3 treated specimens, compared with untreated ones. These effects seemed to be consequences of partial oxidation, as well as improved hydrophilicity and surface decontamination. Finally, it was concluded that, partially oxidized TiN is a promising coating to be used for dental implant. - Highlights: • TiN coating surface was oxidized by hydrothermal or ozone treatment while preserving its hardness. • Improved wettability, decontamination and interstitial N promoted osteoblast responses. • Partial oxidation makes TiN a promising coating for dental implant with good osteoconductivity.

  11. Partial oxidation of TiN coating by hydrothermal treatment and ozone treatment to improve its osteoconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xingling [School of Material Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003 (China); Department of Biomaterials, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582 (Japan); Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huaian 223003 (China); Xu, Lingli, E-mail: linly311@163.com [School of Material Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003 (China); Le, Thi Bang [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Zhou, Guanghong [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huaian 223003 (China); Zheng, Chuanbo, E-mail: zjust316@163.com [School of Material Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003 (China); Tsuru, Kanji; Ishikawa, Kunio [Department of Biomaterials, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582 (Japan)

    2016-02-01

    Dental implants made of pure titanium suffer from abrasion and scratch during routine oral hygiene procedures. This results in an irreversible surface damage, facilitates bacteria adhesion and increases risk of peri-implantitis. To overcome these problems, titanium nitride (TiN) coating was introduced to increase surface hardness of pure titanium. However, the osteoconductivity of TiN is considered to be similar or superior to that of titanium and its alloys and therefore surface modification is necessary. In this study, TiN coating prepared through gas nitriding was partially oxidized by hydrothermal (HT) treatment and ozone (O{sub 3}) treatment in pure water to improve its osteoconductivity. The effects of HT treatment and O{sub 3} treatment on surface properties of TiN were investigated and the osteoconductivity after undergoing treatment was assessed in vitro using osteoblast evaluation. The results showed that the critical temperature for HT treatment was 100 °C since higher temperatures would impair the hardness of TiN coating. By contrast, O{sub 3} treatment was more effective in oxidizing TiN surfaces, improving its wettability while preserving its morphology and hardness. Osteoblast attachment, proliferation, alkaline phosphatase (ALP) expression and mineralization were improved on oxidized specimens, especially on O{sub 3} treated specimens, compared with untreated ones. These effects seemed to be consequences of partial oxidation, as well as improved hydrophilicity and surface decontamination. Finally, it was concluded that, partially oxidized TiN is a promising coating to be used for dental implant. - Highlights: • TiN coating surface was oxidized by hydrothermal or ozone treatment while preserving its hardness. • Improved wettability, decontamination and interstitial N promoted osteoblast responses. • Partial oxidation makes TiN a promising coating for dental implant with good osteoconductivity.

  12. Behavior of gadolinium-based diagnostics in water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Cyris, Maike

    2013-04-25

    Wastewater treatment plants throughout Europe are retrofitted for a sufficient removal of micropollutants. Most target compounds are eliminated efficiently at reasonable costs by oxidation. Sorption processes, on the other hand, are favored as no transformation products are formed. For oxidation, ozone is preferred presently. Its action is divided in two main reaction pathways: Via ozone and via hydroxyl radicals formed by ozone-matrix reactions. Oxidation efficiency strongly depends on reaction rate constants. Sorption processes are usually characterized, including sorption strength, by determination of isotherms. Also, for description of filtration processes isotherm data are necessary. So far, gadolinium chelates, used as contrast agents in magnetic resonance imaging, have not been investigated in both advanced wastewater treatment processes. The stable chelates are excreted without metabolization. Conventional wastewater treatment does not remove them substantially. They remain intact and no free Gd(III) is released. This may be changed due to oxidative treatment which potentially destroys the chelates, and Gd(III) ions which are toxic, contrary to the chelated form, may be liberated. Monitoring campaigns in wastewater and drinking water have been performed to demonstrate the relevance of gadolinium in such treatment steps. In a European monitoring campaign an average concentration of 118 ng L{sup -1} gadolinium has been determined for 75 wastewater treatment plants effluents, corresponding to a non-geogenic gadolinium concentration of 116 ng L{sup -1}. In drinking water in the Ruhr area, a densely populated region in Germany, gadolinium and the anomaly were measurable by a factor of five lower than the average in the investigated wastewater samples. The determined concentrations in drinking water are lower than acute toxic effect concentration. The speciation of gadolinium in the investigated samples is unknown, as only total element concentration has been

  13. Behavior of gadolinium-based diagnostics in water treatment

    International Nuclear Information System (INIS)

    Cyris, Maike

    2013-01-01

    Wastewater treatment plants throughout Europe are retrofitted for a sufficient removal of micropollutants. Most target compounds are eliminated efficiently at reasonable costs by oxidation. Sorption processes, on the other hand, are favored as no transformation products are formed. For oxidation, ozone is preferred presently. Its action is divided in two main reaction pathways: Via ozone and via hydroxyl radicals formed by ozone-matrix reactions. Oxidation efficiency strongly depends on reaction rate constants. Sorption processes are usually characterized, including sorption strength, by determination of isotherms. Also, for description of filtration processes isotherm data are necessary. So far, gadolinium chelates, used as contrast agents in magnetic resonance imaging, have not been investigated in both advanced wastewater treatment processes. The stable chelates are excreted without metabolization. Conventional wastewater treatment does not remove them substantially. They remain intact and no free Gd(III) is released. This may be changed due to oxidative treatment which potentially destroys the chelates, and Gd(III) ions which are toxic, contrary to the chelated form, may be liberated. Monitoring campaigns in wastewater and drinking water have been performed to demonstrate the relevance of gadolinium in such treatment steps. In a European monitoring campaign an average concentration of 118 ng L -1 gadolinium has been determined for 75 wastewater treatment plants effluents, corresponding to a non-geogenic gadolinium concentration of 116 ng L -1 . In drinking water in the Ruhr area, a densely populated region in Germany, gadolinium and the anomaly were measurable by a factor of five lower than the average in the investigated wastewater samples. The determined concentrations in drinking water are lower than acute toxic effect concentration. The speciation of gadolinium in the investigated samples is unknown, as only total element concentration has been determined

  14. Capsid protein oxidation in feline calicivirus using an electrochemical inactivation treatment

    Energy Technology Data Exchange (ETDEWEB)

    Shionoiri, Nozomi; Nogariya, Osamu; Tanaka, Masayoshi; Matsunaga, Tadashi; Tanaka, Tsuyoshi, E-mail: tsuyo@cc.tuat.ac.jp

    2015-02-11

    Highlights: • Feline calicivirus was inactivated electrochemically by a factor of >5 log. • The electrochemical treatment was performed at 0.9 V (vs. Ag/AgCl) for 15 min. • Electrochemical treatment caused oxidation of viral proteins. • Oxidation of viral proteins can lead to loss of viral structural integrity. - Abstract: Pathogenic viral infections are an international public health concern, and viral disinfection has received increasing attention. Electrochemical treatment has been used for treatment of water contaminated by bacteria for several decades, and although in recent years several reports have investigated viral inactivation kinetics, the mode of action of viral inactivation by electrochemical treatment remains unclear. Here, we demonstrated the inactivation of feline calicivirus (FCV), a surrogate for human noroviruses, by electrochemical treatment in a developed flow-cell equipped with a screen-printed electrode. The viral infectivity titer was reduced by over 5 orders of magnitude after 15 min of treatment at 0.9 V vs. Ag/AgCl. Proteomic study of electrochemically inactivated virus revealed oxidation of peptides located in the viral particles; oxidation was not observed in the non-treated sample. Furthermore, transmission electron microscopy revealed that viral particles in the treated sample had irregular structures. These results suggest that electrochemical treatment inactivates FCV via oxidation of peptides in the structural region, causing structural deformation of virus particles. This first report of viral protein damage through electrochemical treatment will contribute to broadening the understanding of viral inactivation mechanisms.

  15. Circulating oxidative stress caused by Psoroptes natalensis infestation in Indian water buffaloes.

    Science.gov (United States)

    Mahajan, Sumit; Panigrahi, Padma Nibash; Dey, Sahadeb; Dan, Ananya; Kumar, Akhilesh; Mahendran, K; Maurya, P S

    2017-09-01

    The present study reports the circulating oxidative stress associated with Psoroptes natalensis infestation in Indian water buffaloes. Three non-descriptive water buffaloes, age ranging between 4 and 9 years, presented to Referral Veterinary Polyclinic, IVRI, for treatment served as clinical subject. The infested animals were treated with Ivermectin subcutaneously and Amitraz topically along with antioxidant like ascorbic acid, Vitamin E and selenium. The level of lipid peroxidase was significantly higher (3.94 ± 0.34) in Psoroptes infested buffalo and was reduced significantly ( P  ≤ 0.05) after treatment (1.56 ± 0.40). The significantly higher levels of MDA before treatment signify the role of lipid peroxide mediated skin lesions in P. natalensis infested buffaloes. Similarly the activities of the body antioxidant like GSH and CAT were significantly higher ( P  ≤ 0.05) after treatment. The less level of the body antioxidant (GSH) and reduced activities of the antioxidant enzymes like CAT and SOD before treatment imply that Psoroptes mite-infested buffaloes were in a state of significant oxidative stress. The study provides information on oxidative stress indices in P. natalensis infested buffaloes and gives additional insight regarding the pathogenesis of the disease and its management.

  16. New electrochemical and photochemical systems for water and wastewater treatment

    International Nuclear Information System (INIS)

    Sarria, Victor M; Parra, Sandra; Rincon, Angela G; Torres, Ricardo A; Pulgarin, Cesar

    2005-01-01

    With the increasing pressure on a more effective use of water resources, the development of appropriate water treatment technologies become more and more important. Photochemical and electrochemical oxidation processes have been proposed in recent years as an attractive alternative for the treatment of contaminated water containing anthropogenic substances hardly biodegradable as well as to purify and disinfect drinking waters. The aim of this paper is to present some of our last results demonstrating that electrochemical, photochemical, and the coupling of these processes with biological systems are very promising alternatives for the improvement of the water quality

  17. Comparison of microbial community shifts in two parallel multi-step drinking water treatment processes.

    Science.gov (United States)

    Xu, Jiajiong; Tang, Wei; Ma, Jun; Wang, Hong

    2017-07-01

    Drinking water treatment processes remove undesirable chemicals and microorganisms from source water, which is vital to public health protection. The purpose of this study was to investigate the effects of treatment processes and configuration on the microbiome by comparing microbial community shifts in two series of different treatment processes operated in parallel within a full-scale drinking water treatment plant (DWTP) in Southeast China. Illumina sequencing of 16S rRNA genes of water samples demonstrated little effect of coagulation/sedimentation and pre-oxidation steps on bacterial communities, in contrast to dramatic and concurrent microbial community shifts during ozonation, granular activated carbon treatment, sand filtration, and disinfection for both series. A large number of unique operational taxonomic units (OTUs) at these four treatment steps further illustrated their strong shaping power towards the drinking water microbial communities. Interestingly, multidimensional scaling analysis revealed tight clustering of biofilm samples collected from different treatment steps, with Nitrospira, the nitrite-oxidizing bacteria, noted at higher relative abundances in biofilm compared to water samples. Overall, this study provides a snapshot of step-to-step microbial evolvement in multi-step drinking water treatment systems, and the results provide insight to control and manipulation of the drinking water microbiome via optimization of DWTP design and operation.

  18. Session 6: Water depollution from aniline and phenol by air oxidation and adsorptive-catalytic oxidation in liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Dobrynkin, N.M.; Batygina, M.V.; Noskov, A.S. [Boreskov Institute of Catalysis of Siberian Branch of Russian Academy of Sciences, Pr. Ak. Lavrentieva (Russian Federation)

    2004-07-01

    This paper is devoted to development of carbon catalysts and application of catalytic wet air oxidation for deep cleaning of polluted waters. The described catalysts and method are solving the problem of development environmentally reliable method for fluids treatment and allow carrying out the adsorption of pollutants on carbon CAPM (catalytically active porous material) with following regeneration of the CAPM without the loss of adsorptive qualities. The experiments have shown a principal capability simultaneously to use carbon CAPM as adsorbent and either as catalyst, or as a catalyst support for oxidation of aniline and phenol in water solutions. (authors)

  19. Supramolecular water oxidation with rubda-based catalysts

    KAUST Repository

    Richmond, Craig J.

    2014-11-05

    Extremely slow and extremely fast new water oxidation catalysts based on the Rubda (bda = 2,2′-bipyri-dine-6,6′-dicarboxylate) systems are reported with turnover frequencies in the range of 1 and 900 cycless"1, respectively. Detailed analyses of the main factors involved in the water oxidation reaction have been carried out and are based on a combination of reactivity tests, electrochemical experiments, and DFT calculations. These analyses give a convergent interpretation that generates a solid understanding of the main factors involved in the water oxidation reaction, which in turn allows the design of catalysts with very low energy barriers in all the steps involved in the water oxidation catalytic cycle. We show that for this type of system p-stacking interactions are the key factors that influence reactivity and by adequately controlling them we can generate exceptionally fast water oxidation catalysts.

  20. Mobil pilot unit of the advanced oxidation process for waste water treatment and reuse of the hydrics effluents; Unidade piloto movel de processo oxidativo avancado aplicado a tratamento e reuso de efluentes hidricos

    Energy Technology Data Exchange (ETDEWEB)

    Geraldo, Lucia Maria Limoeiro; Pereira Junior, Oswaldo de Aquino; Henriques, Sheyla de Oliveira Carvalho; Jacinto Junior, Agenor [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    The chemical oxidation processes which generate free hydroxyl radicals are called Advanced Oxidation Process (AOP). These processes have been studied, in the last decades, as a new alternative for pollutants degradation. In the (AOP)'s there are in situ formation of hydroxyl radicals (OH{center_dot}), which are highly oxidant. Its high oxidation strength becomes it indicated in the treatment of effluent with highly refractory contaminants. It can be used as a partial treatment (taking the effluent to more degradable compounds), as a final treatment (taking the effluent to complete mineralization) or as a complementary treatment to other processes, allowing, for example, its reuse. The applicability of this technology in oily water effluents in all segments of the oil industry, has taken to the development, in the LARA (Laboratory of Treatment and Reuse of Waters - CENPES), of the Advanced Oxidation Process Mobile Pilot Unit (AOP's- MU) with capacity up to 1 m3/h. The (AOP's- MU) are able to produce hydroxyl radical from Fenton's reaction, titanium dioxide heterogeneous photo catalysis and hydrogen peroxide, photo-radiated or not. It is equipped with ultraviolet reactors of different wave lengths and power. (author)

  1. Characterizing natural organic matter in drinking water treatment processes and trains

    NARCIS (Netherlands)

    Baghoth, S.A.

    2012-01-01

    Natural organic matter (NOM) generally influences water treatment processes such as coagulation, oxidation, adsorption, and membrane filtration. NOM contributes colour, taste and odour in drinking water, fouls membranes, serves as a precursor for disinfection by-products, increases the exhaustion

  2. Removal of Iron Oxide Scale from Feed-water in Thermal Power Plant by Using Magnetic Separation

    Science.gov (United States)

    Nakanishi, Motohiro; Shibatani, Saori; Mishima, Fumihito; Akiyama, Yoko; Nishijima, Shigehiro

    2017-09-01

    One of the factors of deterioration in thermal power generation efficiency is adhesion of the scale to inner wall in feed-water system. Though thermal power plants have employed All Volatile Treatment (AVT) or Oxygen Treatment (OT) to prevent scale formation, these treatments cannot prevent it completely. In order to remove iron oxide scale, we proposed magnetic separation system using solenoidal superconducting magnet. Magnetic separation efficiency is influenced by component and morphology of scale which changes their property depending on the type of water treatment and temperature. In this study, we estimated component and morphology of iron oxide scale at each equipment in the feed-water system by analyzing simulated scale generated in the pressure vessel at 320 K to 550 K. Based on the results, we considered installation sites of the magnetic separation system.

  3. Mineralizing urban net-zero water treatment: Field experience for energy-positive water management.

    Science.gov (United States)

    Wu, Tingting; Englehardt, James D

    2016-12-01

    An urban net-zero water treatment system, designed for energy-positive water management, 100% recycle of comingled black/grey water to drinking water standards, and mineralization of hormones and other organics, without production of concentrate, was constructed and operated for two years, serving an occupied four-bedroom, four-bath university residence hall apartment. The system comprised septic tank, denitrifying membrane bioreactor (MBR), iron-mediated aeration (IMA) reactor, vacuum ultrafilter, and peroxone or UV/H 2 O 2 advanced oxidation, with 14% rainwater make-up and concomitant discharge of 14% of treated water (ultimately for reuse in irrigation). Chemical oxygen demand was reduced to 12.9 ± 3.7 mg/L by MBR and further decreased to below the detection limit (treatment. The process produced a mineral water meeting 115 of 115 Florida drinking water standards that, after 10 months of recycle operation with ∼14% rainwater make-up, had a total dissolved solids of ∼500 mg/L, pH 7.8 ± 0.4, turbidity 0.12 ± 0.06 NTU, and NO 3 -N concentration 3.0 ± 1.0 mg/L. None of 97 hormones, personal care products, and pharmaceuticals analyzed were detected in the product water. For a typical single-home system with full occupancy, sludge pumping is projected on a 12-24 month cycle. Operational aspects, including disinfection requirements, pH evolution through the process, mineral control, advanced oxidation by-products, and applicability of point-of-use filters, are discussed. A distributed, peroxone-based NZW management system is projected to save more energy than is consumed in treatment, due largely to retention of wastewater thermal energy. Recommendations regarding design and operation are offered. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Treatment of Fatty Acid Oxidation Disorders

    Science.gov (United States)

    ... Treatment of fatty acid oxidation disorders Treatment of fatty acid oxidation disorders E-mail to a friend Please ... this page It's been added to your dashboard . Fatty acid oxidation disorders are rare health conditions that affect ...

  5. Water-oxidation catalysis by synthetic manganese oxides--systematic variations of the calcium birnessite theme.

    Science.gov (United States)

    Frey, Carolin E; Wiechen, Mathias; Kurz, Philipp

    2014-03-21

    Layered manganese oxides from the birnessite mineral family have been identified as promising heterogeneous compounds for water-oxidation catalysis (WOC), a key reaction for the conversion of renewable energy into storable fuels. High catalytic rates were especially observed for birnessites which contain calcium as part of their structures. With the aim to systematically improve the catalytic performance of such oxide materials, we used a flexible synthetic route to prepare three series of calcium birnessites, where we varied the calcium concentrations, the ripening times of the original precipitates and the temperature of the heat treatment following the initial synthetic steps (tempering) during the preparation process. The products were carefully analysed by a number of analytical techniques and then probed for WOC activity using the Ce(4+)-system. We find that our set of twenty closely related manganese oxides shows large, but somewhat systematic alterations in catalytic rates, indicating the importance of synthesis parameters for maximum catalytic performance. The catalyst of the series for which the highest water-oxidation rate was found is a birnessite of medium calcium content (Ca : Mn ratio 0.2 : 1) that had been subjected to a tempering temperature of 400 °C. On the basis of the detailed analysis of the results, a WOC reaction scheme for birnessites is proposed to explain the observed trends in reactivity.

  6. Water quality assessment using the AREc32 reporter gene assay indicative of the oxidative stress response pathway.

    Science.gov (United States)

    Escher, Beate I; Dutt, Mriga; Maylin, Erin; Tang, Janet Y M; Toze, Simon; Wolf, C Roland; Lang, Matti

    2012-11-01

    The reporter gene assay AREc32 is based on the induction of the Nrf2 mediated oxidative stress response pathway in the human breast cancer cell line MCF7, where eight copies of the antioxidant response element (ARE) are linked to a reporter gene encoding for luciferase. The Nrf2-ARE pathway is responsive to many chemicals that cause oxidative stress, among them a large number of pesticides and skin irritants. We adopted and validated the AREc32 bioassay for water quality testing. tert-Butylhydroquinone served as the positive control, phenol as the negative control and other reactive chemicals were assessed for their specificity. An environmentally relevant reference chemical, benzo(a)pyrene was the most potent inducer of all tested chemicals. The concentration causing an induction ratio (IR) of 1.5 (EC(IR1.5)) was chosen as the effect benchmark value. The assay was applied to 21 water samples ranging from sewage to drinking water, including secondary treatment and various tertiary treatment options (ozonation, biologically activated carbon filtration, membrane filtration, reverse osmosis, advanced oxidation, chlorination, chloramination). The samples were enriched by solid phase extraction. In most samples the oxidative stress response was far more sensitive than cytotoxicity. The primary and secondary treated effluent exceeded the effect threshold IR 1.5 at a relative enrichment factor (REF) of 1, i.e., the native samples were active. All tertiary treated samples were less potent and their EC(IR1.5) lay between REF 1 and 10. The Nrf2 pathway was induced at a REF of approximately 10 for surface waters and drinking water, and above this enrichment cytotoxicity took over in most samples and quenched the induction. The blank (ultrapure water run through the sample enrichment process) was cytotoxic at an REF of 100, which is the limit of concentrations range that can be evaluated. Treatment typically decreased both the cytotoxicity and oxidative stress response apart

  7. HEAVY METALS AS UNWANTED COMPONENTS OF BACKWASH WATER DERIVED FROM GROUNDWATER TREATMENT

    Directory of Open Access Journals (Sweden)

    Robert Nowak

    2016-06-01

    Full Text Available The paper presents some aspects of the problem of heavy metals presence in wastewater and sewage sludge from water treatment. In the first part, issues on quality of wastewaters and sludge produced during water treatment along with actions aimed at the neutralization of such wastes, were discussed. Subsequent parts of the work present the example of 12 groundwater treatment stations in a particular municipality, and the problem of backwash water quality, in particular, heavy metals contents. The analysis covered a period of three years: 2013, 2014, and 2015. The authors, using the discussed examples, have shown that besides hydrated iron and manganese oxides, also other toxic contaminants can be present in backwash water from groundwater treatment. In particular, the qualitative analysis of the backwash water revealed the presence of heavy metals, mainly zinc. The test results for backwash water were compared with those of filtrate qualitative assessment, wherein the heavy metals were not found. This fact indicated the metal retention in the filter bed and their unsustainable immobilization resulting in penetration of heavy metals from deposit to the backwash water along with other impurities, mainly iron and manganese oxides. The main conclusion from the study is to demonstrate the need for constant monitoring of the backwash water quality, including the presence of toxic heavy metals. This is also important because of the requirement to minimize the negative environmental impact of wastes generated during the water treatment process.

  8. Atomic origins of water-vapour-promoted alloy oxidation.

    Science.gov (United States)

    Luo, Langli; Su, Mao; Yan, Pengfei; Zou, Lianfeng; Schreiber, Daniel K; Baer, Donald R; Zhu, Zihua; Zhou, Guangwen; Wang, Yanting; Bruemmer, Stephen M; Xu, Zhijie; Wang, Chongmin

    2018-05-07

    The presence of water vapour, intentional or unavoidable, is crucial to many materials applications, such as in steam generators, turbine engines, fuel cells, catalysts and corrosion 1-4 . Phenomenologically, water vapour has been noted to accelerate oxidation of metals and alloys 5,6 . However, the atomistic mechanisms behind such oxidation remain elusive. Through direct in situ atomic-scale transmission electron microscopy observations and density functional theory calculations, we reveal that water-vapour-enhanced oxidation of a nickel-chromium alloy is associated with proton-dissolution-promoted formation, migration, and clustering of both cation and anion vacancies. Protons derived from water dissociation can occupy interstitial positions in the oxide lattice, consequently lowering vacancy formation energy and decreasing the diffusion barrier of both cations and anions, which leads to enhanced oxidation in moist environments at elevated temperatures. This work provides insights into water-vapour-enhanced alloy oxidation and has significant implications in other material and chemical processes involving water vapour, such as corrosion, heterogeneous catalysis and ionic conduction.

  9. Oxidative treatment of bromide-containing waters: formation of bromine and its reactions with inorganic and organic compounds--a critical review.

    Science.gov (United States)

    Heeb, Michèle B; Criquet, Justine; Zimmermann-Steffens, Saskia G; von Gunten, Urs

    2014-01-01

    Bromide (Br(-)) is present in all water sources at concentrations ranging from ≈ 10 to >1000 μg L(-1) in fresh waters and about 67 mg L(-1) in seawater. During oxidative water treatment bromide is oxidized to hypobromous acid/hypobromite (HOBr/OBr(-)) and other bromine species. A systematic and critical literature review has been conducted on the reactivity of HOBr/OBr(-) and other bromine species with inorganic and organic compounds, including micropollutants. The speciation of bromine in the absence and presence of chloride and chlorine has been calculated and it could be shown that HOBr/OBr(-) are the dominant species in fresh waters. In ocean waters, other bromine species such as Br2, BrCl, and Br2O gain importance and may have to be considered under certain conditions. HOBr reacts fast with many inorganic compounds such as ammonia, iodide, sulfite, nitrite, cyanide and thiocyanide with apparent second-order rate constants in the order of 10(4)-10(9)M(-1)s(-1) at pH 7. No rate constants for the reactions with Fe(II) and As(III) are available. Mn(II) oxidation by bromine is controlled by a Mn(III,IV) oxide-catalyzed process involving Br2O and BrCl. Bromine shows a very high reactivity toward phenolic groups (apparent second-order rate constants kapp ≈ 10(3)-10(5)M(-1)s(-1) at pH 7), amines and sulfamides (kapp ≈ 10(5)-10(6)M(-1)s(-1) at pH 7) and S-containing compounds (kapp ≈ 10(5)-10(7)M(-1)s(-1) at pH 7). For phenolic moieties, it is possible to derive second-order rate constants with a Hammett-σ-based QSAR approach with [Formula in text]. A negative slope is typical for electrophilic substitution reactions. In general, kapp of bromine reactions at pH 7 are up to three orders of magnitude greater than for chlorine. In the case of amines, these rate constants are even higher than for ozone. Model calculations show that depending on the bromide concentration and the pH, the high reactivity of bromine may outweigh the reactions of chlorine during

  10. Supercritical Water Oxidation Program (SCWOP)

    International Nuclear Information System (INIS)

    1994-02-01

    Purpose of SCWOP is to develop and demonstrate supercritical water oxidation as a viable technology for treating DOE hazardous and mixed wastes and to coordinate SCWO research, development, demonstration, testing, and evaluation activities. The process involves bringing together organic waste, water, and an oxidant (air, O 2 , etc.) to temperatures and pressures above water's critical point (374 C, 22.1 MPa); organic destruction is >99.99% efficient, and the resulting effluents (mostly water, CO 2 ) are relatively benign. Pilot-scale (300--500 gallons/day) SCWO units are to be constructed and demonstrated. Two phases will be conducted: hazardous waste pilot plant demonstration and mixed waste pilot demonstration. Contacts for further information and for getting involved are given

  11. Zinc oxide nanoparticles for water disinfection

    Directory of Open Access Journals (Sweden)

    Emelita Asuncion S. Dimapilis

    2018-03-01

    Full Text Available The world faces a growing challenge for adequate clean water due to threats coming from increasing demand and decreasing supply. Although there are existing technologies for water disinfection, their limitations, particularly the formation of disinfection-by-products, have led to researches on alternative methods. Zinc oxide, an essential chemical in the rubber and pharmaceutical industries, has attracted interest as antimicrobial agent. In nanoscale, zinc oxide has shown antimicrobial properties which make its potential great for various applications. This review discusses the synthesis of zinc oxide with focus on precipitation method, its antimicrobial property and the factors affecting it, disinfection mechanisms, and the potential application to water disinfection.

  12. Treatment for hydrazine-containing waste water solution

    Science.gov (United States)

    Yade, N.

    1986-01-01

    The treatment for waste solutions containing hydrazine is presented. The invention attempts oxidation and decomposition of hydrazine in waste water in a simple and effective processing. The method adds activated charcoal to waste solutions containing hydrazine while maintaining a pH value higher than 8, and adding iron salts if necessary. Then, the solution is aerated.

  13. Engineering aspects of ferrate in water and wastewater treatment - a review.

    Science.gov (United States)

    Yates, Brian J; Zboril, Radek; Sharma, Virender K

    2014-01-01

    There is renewed interest in the tetra-oxy compound of +6 oxidation states of iron, ferrate(VI) (Fe(VI)O4(2-)), commonly called ferrate. Ferrate has the potential in cleaner ("greener") technologies for water treatment and remediation processes, as it produces potentially less toxic byproducts than other treatment chemicals (e.g., chlorine). Ferrate has strong potential to oxidize a number of contaminants, including sulfur- and nitrogen-containing compounds, estrogens, and antibiotics. This oxidation capability of ferrate combines with its efficient disinfection and coagulation properties as a multi-purpose treatment chemical in a single dose. This review focuses on the engineering aspects of ferrate use at the pilot scale to remove contaminants in and enhance physical treatment of water and wastewater. In most of the pilot-scale studies, in-line and on-line electrochemical ferrate syntheses have been applied. In this ferrate synthesis, ferrate was directly prepared in solution from an iron anode, followed by direct addition to the contaminant stream. Some older studies applied ferrate as a solid. This review presents examples of removing a range of contaminants by adding ferrate solution to the stream. Results showed that ferrate alone and in combination with additional coagulants can reduce total suspended solids (TSS), chemical oxygen demand (COD), biological oxygen demand (BOD), and organic matter. Ferrate also oxidizes cyanide, sulfide, arsenic, phenols, anilines, and dyes and disinfects a variety of viruses and bacteria. Limitations and drawbacks of the application of ferrate in treating contaminated water on the pilot scale are also presented.

  14. Phenol wastewater remediation: advanced oxidation processes coupled to a biological treatment.

    Science.gov (United States)

    Rubalcaba, A; Suárez-Ojeda, M E; Stüber, F; Fortuny, A; Bengoa, C; Metcalfe, I; Font, J; Carrera, J; Fabregat, A

    2007-01-01

    Nowadays, there are increasingly stringent regulations requiring more and more treatment of industrial effluents to generate product waters which could be easily reused or disposed of to the environment without any harmful effects. Therefore, different advanced oxidation processes were investigated as suitable precursors for the biological treatment of industrial effluents containing phenol. Wet air oxidation and Fenton process were tested batch wise, while catalytic wet air oxidation and H2O2-promoted catalytic wet air oxidation processes were studied in a trickle bed reactor, the last two using over activated carbon as catalyst. Effluent characterisation was made by means of substrate conversion (using high liquid performance chromatography), chemical oxygen demand and total organic carbon. Biodegradation parameters (i.e. maximum oxygen uptake rate and oxygen consumption) were obtained from respirometric tests using activated sludge from an urban biological wastewater treatment plant (WWTP). The main goal was to find the proper conditions in terms of biodegradability enhancement, so that these phenolic effluents could be successfully treated in an urban biological WWTP. Results show promising research ways for the development of efficient coupled processes for the treatment of wastewater containing toxic or biologically non-degradable compounds.

  15. Uranium oxidation: Characterization of oxides formed by reaction with water by infrared and sorption analyses

    Science.gov (United States)

    Fuller, E. L.; Smyrl, N. R.; Condon, J. B.; Eager, M. H.

    1984-04-01

    Three different uranium oxide samples have been characterized with respect to the different preparation techniques. The results show that the water reaction with uranium metal occurs cyclically forming laminar layers of oxide which spall off due to the strain at the oxide/metal interface. Single laminae are released if liquid water is present due to the prizing penetration at the reaction zone. The rate of reaction of water with uranium is directly proportional to the amount of adsorbed water on the oxide product. Rapid transport is effected through the open hydrous oxide product. Dehydration of the hydrous oxide irreversibly forms a more inert oxide which cannot be rehydrated to the degree that prevails in the original hydrous product of uranium oxidation with water. Inert gas sorption analyses and diffuse reflectance infrared studies combined with electron microscopy prove valuable in defining the chemistry and morphology of the oxidic products and hydrated intermediates.

  16. Radiation chemical studies on the treatment of waste water

    International Nuclear Information System (INIS)

    Sakumoto, Akihisa; Miyata, Teijiro; Arai, Michimasa; Arai, Hidehiko

    1982-10-01

    The radiation induced reaction in aqueous solution was studied to develope the radiation treatment as a new technique for waste water and to elevate the effectiveness of radiation. The effectiveness of radiation was enhanced by combination of radiation induced reaction with conventional methods such as biological treatment and coagulation treatment. The synergistic effect of radiation and ozone was studied by using phenol and ethylene glycol. The chain reaction was observed in the radiation induced oxidation. The combination of radiation and ozone is considered to be one of the most useful method. In this report, the mechanism of each reaction and the applicability of the reaction to the treatment of waste water are discussed. (author)

  17. Evaluating Nanoparticle Breakthrough during Drinking Water Treatment

    Science.gov (United States)

    Chalew, Talia E. Abbott; Ajmani, Gaurav S.; Huang, Haiou

    2013-01-01

    Background: Use of engineered nanoparticles (NPs) in consumer products is resulting in NPs in drinking water sources. Subsequent NP breakthrough into treated drinking water is a potential exposure route and human health threat. Objectives: In this study we investigated the breakthrough of common NPs—silver (Ag), titanium dioxide (TiO2), and zinc oxide (ZnO)—into finished drinking water following conventional and advanced treatment. Methods: NPs were spiked into five experimental waters: groundwater, surface water, synthetic freshwater, synthetic freshwater containing natural organic matter, and tertiary wastewater effluent. Bench-scale coagulation/flocculation/sedimentation simulated conventional treatment, and microfiltration (MF) and ultrafiltration (UF) simulated advanced treatment. We monitored breakthrough of NPs into treated water by turbidity removal and inductively coupled plasma–mass spectrometry (ICP-MS). Results: Conventional treatment resulted in 2–20%, 3–8%, and 48–99% of Ag, TiO2, and ZnO NPs, respectively, or their dissolved ions remaining in finished water. Breakthrough following MF was 1–45% for Ag, 0–44% for TiO2, and 36–83% for ZnO. With UF, NP breakthrough was 0–2%, 0–4%, and 2–96% for Ag, TiO2, and ZnO, respectively. Variability was dependent on NP stability, with less breakthrough of aggregated NPs compared with stable NPs and dissolved NP ions. Conclusions: Although a majority of aggregated or stable NPs were removed by simulated conventional and advanced treatment, NP metals were detectable in finished water. As environmental NP concentrations increase, we need to consider NPs as emerging drinking water contaminants and determine appropriate drinking water treatment processes to fully remove NPs in order to reduce their potential harmful health outcomes. Citation: Abbott Chalew TE, Ajmani GS, Huang H, Schwab KJ. 2013. Evaluating nanoparticle breakthrough during drinking water treatment. Environ Health Perspect 121

  18. Nanostructured manganese oxide/carbon nanotubes, graphene and graphene oxide as water-oxidizing composites in artificial photosynthesis.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Rahimi, Fahime; Fathollahzadeh, Maryam; Haghighi, Behzad; Hołyńska, Małgorzata; Tomo, Tatsuya; Allakhverdiev, Suleyman I

    2014-07-28

    Herein, we report on nano-sized Mn oxide/carbon nanotubes, graphene and graphene oxide as water-oxidizing compounds in artificial photosynthesis. The composites are synthesized by different and simple procedures and characterized by a number of methods. The water-oxidizing activities of these composites are also considered in the presence of cerium(IV) ammonium nitrate. Some composites are efficient Mn-based catalysts with TOF (mmol O2 per mol Mn per second) ~ 2.6.

  19. Relationship between oxide film structures and corrosion resistance of SUS 304 L stainless steel in high temperature pure water

    International Nuclear Information System (INIS)

    Yamanaka, Kazuo; Matsuda, Yasushi.

    1990-01-01

    The effect of various oxidation conditions on metal release of SUS304L stainless steels in deaerated pure water at 488 K was investigated. The behavior of metal release was also discussed in relation to the surface films which were formed by various oxidation treatments. The results obtained are as follows: (1) The oxidation treatment in high purity argon gas at high temperatures for short time such as 1273 K - 2 min (120S) was effective to decrease the metal dissolution, and the oxide films primarily consisted of spinel type double oxide layer containing high concentration of Mn and Cr. (2) The oxidation treatments in non-deaerated pure water at 561 K for 24∼336 h (86.4∼1209.6 ks) were furthermore effective to decrease the metal dissolution. (3) It may be concluded that the key factors controlling the metal release are thickness, structure and compactness together with compositions of surface oxide films. (author)

  20. Treatment rate improvement of the ozone oxidation method for laundry waste water

    International Nuclear Information System (INIS)

    Matsuo, Toshiaki; Nishi, Takashi

    2001-01-01

    Radioactive laundry waste water generated in nuclear power plants includes organic compounds to be removed, for which ozone oxidation treatment is a possibility. To verify the applicability, its total organic carbon concentration (TOC) lowering rate improvement was examined in 0.5x10 -3 m 3 batch and 3x10 -2 m 3 pilot equipment experiments. In the batch experiments, ozone at a concentration of 200 g/Nm 3 was dispersed into 0.5x10 -3 m 3 of Simulated Laundry Waste Water (SLWW) with TOC of 11 mM. Total organic carbon concentration was measured every hour to see the effects of the temperature, and the initial concentrations of both H 2 O 2 and NaOH which were added to urge OH radical generation from ozone. In the pilot equipment experiments, 1x10 -2 to 3x10 -2 m 3 of the SLWW were circulated using an ejector to disperse the ozone. The influences of the flow rate and the SLWW volume on lowering TOC were examined, because they were related to the ejector dispersion performance and the appropriate ozone addition per SLWW volume. Appropriate initial H 2 O 2 and NaOH concentrations in the batch experiments were 14.7 mM and 1 mM, respectively. Lowering of TOC became faster at higher temperatures, because ozone self-decomposition and OH radial diffusion to the organic compound molecules were promoted. Lowering of TOC also became faster at higher flow rates, while the influence of the volume became saturated. (author)

  1. AN INVESTIGATION OF ARSENIC MOBILITY FROM IRON OXIDE SOLIDS PRODUCED DURING DRINKING WATER TREATMENT

    Science.gov (United States)

    The Arsenic Rule under the Safe Drinking Water Act will require certain drinking water suppliers to add to or modify their existing treatment in order to comply with the regulations. One of the treatment options is iron co-precipitation. This treatment is attractive because ars...

  2. Ammonia- and Nitrite-Oxidizing Bacterial Communities in a Pilot-Scale Chloraminated Drinking Water Distribution System

    OpenAIRE

    Regan, John M.; Harrington, Gregory W.; Noguera, Daniel R.

    2002-01-01

    Nitrification in drinking water distribution systems is a common operational problem for many utilities that use chloramines for secondary disinfection. The diversity of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the distribution systems of a pilot-scale chloraminated drinking water treatment system was characterized using terminal restriction fragment length polymorphism (T-RFLP) analysis and 16S rRNA gene (ribosomal DNA [rDNA]) cloning and sequencing. For ammon...

  3. A study on oxidation treatment of uranium metal chip under controlling atmosphere for safe storage

    International Nuclear Information System (INIS)

    Kim, Chang Kyu; Ji, Chul Goo; Bae, Sang Oh; Woo, Yoon Myeoung; Kim, Jong Goo; Ha, Yeong Keong

    2011-01-01

    The U metal chips generated in developing nuclear fuel and a gamma radioisotope shield have been stored under immersion of water in KAERI. When the water of the storing vessels vaporizes or drains due to unexpected leaking, the U metal chips are able to open to air. A new oxidation treatment process was raised for a long time safe storage with concepts of drying under vacuum, evaporating the containing water and organic material with elevating temperature, and oxidizing the uranium metal chips at an appropriate high temperature under conditions of controlling the feeding rate of oxygen gas. In order to optimize the oxidation process the uranium metal chips were completely dried at higher temperature than 300 .deg. C and tested for oxidation at various temperatures, which are 300 .deg. C, 400 .deg. C, and 500 .deg. C. When the oxidation temperature was 400 .deg. C, the oxidized sample for 7 hours showed a temperature rise of 60 .deg. C in the self-ignition test. But the oxidized sample for 14 hours revealed a slight temperature rise of 7 .deg. C representing a stable behavior in the self-ignition test. When the temperature was 500 .deg. C, the shorter oxidation for 7 hours appeared to be enough because the self-ignition test represented no temperature rise. By using several chemical analyses such as carbon content determination, X-ray deflection (XRD), Infrared spectra (IR) and Thermal gravimetric analysis (TGA) on the oxidation treated samples, the results of self-ignition test of new oxidation treatment process for U metal chip were interpreted and supported

  4. Synthesis of magnetic iron oxide nanoparticles toward arsenic removal from drinking water

    International Nuclear Information System (INIS)

    Starbird Perez, Ricardo; Montero Campos, Virginia

    2015-01-01

    A high contact area material is supplied to be used in the treatment of water contaminated with arsenic. Synthesis of iron nanoparticles is reported with superparamagnetic properties, stabilized with stearic acid. The characterization is performed through spectrophotometric, thermogravimetric and electronic transmission techniques. The presence of an emulsifier is evidenced and determinant for the stabilization of the iron oxide phase (maghemite or magnetite) with magnetic properties. The material is obtained and shows suitable properties to be used in the treatment of water for human consumption. (author) [es

  5. Semiconductor photocatalysts for water oxidation: current status and challenges.

    Science.gov (United States)

    Yang, Lingling; Zhou, Han; Fan, Tongxiang; Zhang, Di

    2014-04-21

    Artificial photosynthesis is a highly-promising strategy to convert solar energy into hydrogen energy for the relief of the global energy crisis. Water oxidation is the bottleneck for its kinetic and energetic complexity in the further enhancement of the overall efficiency of the artificial photosystem. Developing efficient and cost-effective photocatalysts for water oxidation is a growing desire, and semiconductor photocatalysts have recently attracted more attention due to their stability and simplicity. This article reviews the recent advancement of semiconductor photocatalysts with a focus on the relationship between material optimization and water oxidation efficiency. A brief introduction to artificial photosynthesis and water oxidation is given first, followed by an explanation of the basic rules and mechanisms of semiconductor particulate photocatalysts for water oxidation as theoretical references for discussions of componential, surface structure, and crystal structure modification. O2-evolving photocatalysts in Z-scheme systems are also introduced to demonstrate practical applications of water oxidation photocatalysts in artificial photosystems. The final part proposes some challenges based on the dynamics and energetics of photoholes which are fundamental to the enhancement of water oxidation efficiency, as well as on the simulation of natural water oxidation that will be a trend in future research.

  6. Treatment of water closet flush water for recycle and reuse

    Energy Technology Data Exchange (ETDEWEB)

    Parker, C.E.

    1985-01-01

    Results from the operation of a 37.8 m/sup 3//d extended aeration and sand filtration system in the closed-loop treatment of water closet flush water are presented. The system has operated for four and one-half years at 95 percent recycle. During this period over 30,000 m/sup 3/ of flush water was treated and reused. Water inputs into the recycle system resulted from liquid human wastes plus wastage form potable water uses. Wasted potable water inputs were from wash basins, water fountains and custodial services. Operation of both the biological treatment unit and the pressure sand filter followed acceptable conventional practice. Variations in nitrogen (ammonia, nitrite and nitrate), pH and alkalinity that were observed could be accounted for through fundamental biological, chemical and physical relationships. The pH throughout the entire recycle system varied between 5.5 and 8.4. Recycled water pH rose from a preflush pH of approximately 7.0 to a pH of 8.4 immediately after flushing. The biological unit lowered the pH and functioned between pH values of 5.5 and 7.0. A slight rise in pH between the biological unit (through storage and filtration) and water closets was observed. The predominate biomass in the biological unit was fungi. Biological solids were threadlike; however, they readily separated by gravity settling. Wastage of biological solids from the biological unit in the recycle-reuse system was the same experienced for a comparable biological unit used to treat water closet wastewater that was not recycled. Results from this study have conclusively demonstrated on a full-scale basis the acceptability of using biological oxidation and sand filtration as a treatment train in the reuse of water closet wastewater with a recycle ratio of 20.

  7. Methane oxidation in anoxic lake waters

    Science.gov (United States)

    Su, Guangyi; Zopfi, Jakob; Niemann, Helge; Lehmann, Moritz

    2017-04-01

    Freshwater habitats such as lakes are important sources of methante (CH4), however, most studies in lacustrine environments so far provided evidence for aerobic methane oxidation only, and little is known about the importance of anaerobic oxidation of CH4 (AOM) in anoxic lake waters. In marine environments, sulfate reduction coupled to AOM by archaea has been recognized as important sinks of CH4. More recently, the discorvery of anaerobic methane oxidizing denitrifying bacteria represents a novel and possible alternative AOM pathway, involving reactive nitrogen species (e.g., nitrate and nitrite) as electron acceptors in the absence of oxygen. We investigate anaerobic methane oxidation in the water column of two hydrochemically contrasting sites in Lake Lugano, Switzerland. The South Basin displays seasonal stratification, the development of a benthic nepheloid layer and anoxia during summer and fall. The North Basin is permanently stratified with anoxic conditions below 115m water depth. Both Basins accumulate seasonally (South Basin) or permanently (North Basin) large amounts of CH4 in the water column below the chemocline, providing ideal conditions for methanotrophic microorganisms. Previous work revealed a high potential for aerobic methane oxidation within the anoxic water column, but no evidence for true AOM. Here, we show depth distribution data of dissolved CH4, methane oxidation rates and nutrients at both sites. In addition, we performed high resolution phylogenetic analyses of microbial community structures and conducted radio-label incubation experiments with concentrated biomass from anoxic waters and potential alternative electron acceptor additions (nitrate, nitrite and sulfate). First results from the unamended experiments revealed maximum activity of methane oxidation below the redoxcline in both basins. While the incubation experiments neither provided clear evidence for NOx- nor sulfate-dependent AOM, the phylogenetic analysis revealed the

  8. Supercritical Water Oxidation: A Solution for the Elimination of Back-End Organic Reprocessing Wastes

    Energy Technology Data Exchange (ETDEWEB)

    Leybros, A.; Roubaud, A.; Turc, H.A.; Fournel, B. [Supercritical fluids and membranes Laboratory, CEA Valrho, BP 17171, 30207 Bagnols/Ceze Cedex (France)

    2008-07-01

    Supercritical water oxidation (SCWO) is a very efficient technique for total elimination of organic wastes from reprocessing activities on the way of 'zero wastes' facilities. This technology uses the properties of supercritical water (P > 221 bars and T > 647 K) to obtain a good mixing between oxygen (the oxidant) and the organic waste. Thereby, the oxidation reaction is fast and complete. Using the SCWO process, contamination contained in organic materials like spent solvents can be confined in a closed space, like a reactor in a glovebox. A new application is tested for the treatment of solid organic wastes like ion exchange resins (IER). Experiments are made with suspensions of IER in water and isopropyl-alcohol. A nuclear version of the process with the double shell reactor has been constructed and is being tested. The aim of this work is to obtain a treatment capacity of 1 kg/h for the nuclear version with the same global set-up, concept of process and security as well as contamination management as for a 200 g/h pilot. (authors)

  9. Supercritical Water Oxidation: A Solution for the Elimination of Back-End Organic Reprocessing Wastes

    International Nuclear Information System (INIS)

    Leybros, A.; Roubaud, A.; Turc, H.A.; Fournel, B.

    2008-01-01

    Supercritical water oxidation (SCWO) is a very efficient technique for total elimination of organic wastes from reprocessing activities on the way of 'zero wastes' facilities. This technology uses the properties of supercritical water (P > 221 bars and T > 647 K) to obtain a good mixing between oxygen (the oxidant) and the organic waste. Thereby, the oxidation reaction is fast and complete. Using the SCWO process, contamination contained in organic materials like spent solvents can be confined in a closed space, like a reactor in a glovebox. A new application is tested for the treatment of solid organic wastes like ion exchange resins (IER). Experiments are made with suspensions of IER in water and isopropyl-alcohol. A nuclear version of the process with the double shell reactor has been constructed and is being tested. The aim of this work is to obtain a treatment capacity of 1 kg/h for the nuclear version with the same global set-up, concept of process and security as well as contamination management as for a 200 g/h pilot. (authors)

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

    Science.gov (United States)

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

  11. Supramolecular water oxidation with Ru-bda-based catalysts.

    Science.gov (United States)

    Richmond, Craig J; Matheu, Roc; Poater, Albert; Falivene, Laura; Benet-Buchholz, Jordi; Sala, Xavier; Cavallo, Luigi; Llobet, Antoni

    2014-12-22

    Extremely slow and extremely fast new water oxidation catalysts based on the Ru-bda (bda=2,2'-bipyridine-6,6'-dicarboxylate) systems are reported with turnover frequencies in the range of 1 and 900 cycles s(-1) , respectively. Detailed analyses of the main factors involved in the water oxidation reaction have been carried out and are based on a combination of reactivity tests, electrochemical experiments, and DFT calculations. These analyses give a convergent interpretation that generates a solid understanding of the main factors involved in the water oxidation reaction, which in turn allows the design of catalysts with very low energy barriers in all the steps involved in the water oxidation catalytic cycle. We show that for this type of system π-stacking interactions are the key factors that influence reactivity and by adequately controlling them we can generate exceptionally fast water oxidation catalysts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. FATE OF REVERSE OSMOSIS (RO) MEMBRANES DURING OXIDATION BY DISINFECTANTS USED IN WATER TREATMENT: IMPACT ON MEMBRANE STRUCTURE AND PERFORMANCES

    KAUST Repository

    Maugin, Thomas

    2013-12-01

    Providing pretreatment prior RO filtration is essential to avoid biofouling and subsequent loss of membrane performances. Chlorine is known to degrade polymeric membrane, improving or reducing membrane efficiency depending on oxidation conditions. This study aimed to assess the impact of alternative disinfectant, NH2Cl, as well as secondary oxidants formed during chloramination of seawater, e.g. HOBr, HOI, or used in water treatment e.g. ClO2, O3, on membrane structure and performances. Permeability, total and specific rejection (Cl-, SO4 2-, Br-, Boron), FTIR profile, elemental composition were analyzed. Results showed that each oxidant seems to react differently with the membrane. HOCl, HOBr, ClO2 and O3 improved membrane permeability but decreased rejection in different extent. In comparison, chloramines resulted in identical trends but oxidized membrane very slowly. On the contrary, iodine improved membrane rejection e.g. boron, but decreased permeability. Reaction conducted with chlorine, bromine, iodine and chloramines resulted in the incorporation of halogen in the membrane structure. All oxidant except iodine were able to break amide bonds of the membrane structure in our condition. In addition, chloramine seemed to react with membrane differently, involving a potential addition of nitrogen. Chloramination of seawater amplified membrane performances evolutions due to generation of bromochloramine. Moreover, chloramines reacted both with NOM and membrane during oxidation in natural seawater, leading to additional rejection drop.

  13. Ultrasound applications and ionizing radiations in water treatment

    International Nuclear Information System (INIS)

    Al-Oraby, M.N.A.

    2013-01-01

    Application of ultrasound irradiation is one of the innovative techniques that was used for improvement of water treatment process and lowering levels of contaminants in waste water. The main mechanism of sonication is based on the cavitation phenomenon which includes the whole procedure of creation, expansion and collapsing of micro bubbles throughout liquid phase when negative pressure is applied to the medium during sonication. Consequently, hydroxyl and hydrogen radicals would be formed by thermal dissociation of water and hydrogen. These radicals penetrate into water and oxidize dissolved organic compounds. Hydrogen peroxide is formed as a consequence of hydroxyl and water radical recombination. During the free radical attack, the cell membranes of microorganisms are ruptured physically. The application of ionizing radiation for the removal of odorific substances and organic pollutants from water is an advanced oxidation process based on fast reactions with hydroxyl radicals formed as a result of radiolysis of water. GEO and MIB are the main responsible organic composites for the taste and odor in water. These compounds and other organic pollutants such as herbicide 2,4-DCP can be removed by different doses of gamma rays depending on magnitude, rate of radiation dose, chemical condition of the process and other factors. (author)

  14. Advanced oxidation processes for the removal of natural organic matter from drinking water sources: A comprehensive review.

    Science.gov (United States)

    Sillanpää, Mika; Ncibi, Mohamed Chaker; Matilainen, Anu

    2018-02-15

    Natural organic matter (NOM), a key component in aquatic environments, is a complex matrix of organic substances characterized by its fluctuating amounts in water and variable molecular and chemical properties, leading to various interaction schemes with the biogeosphere and hydrologic cycle. These factors, along with the increasing amounts of NOM in surface and ground waters, make the effort of removing naturally-occurring organics from drinking water supplies, and also from municipal wastewater effluents, a challenging task requiring the development of highly efficient and versatile water treatment technologies. Advanced oxidation processes (AOPs) received an increasing amount of attention from researchers around the world, especially during the last decade. The related processes were frequently reported to be among the most suitable water treatment technologies to remove NOM from drinking water supplies and mitigate the formation of disinfection by products (DBPs). Thus, the present work overviews recent research and development studies conducted on the application of AOPs to degrade NOM including UV and/or ozone-based applications, different Fenton processes and various heterogeneous catalytic and photocatalytic oxidative processes. Other non-conventional AOPs such as ultrasonication, ionizing radiation and plasma technologies were also reported. Furthermore, since AOPs are unlikely to achieve complete oxidation of NOM, integration schemes with other water treatment technologies were presented including membrane filtration, adsorption and others processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. A comparative view of radiation, photo and photocatalytically induced oxidation of water pollutants

    International Nuclear Information System (INIS)

    Getoff, N.

    1997-01-01

    Water resources are presently overloaded with biologically resistant (refractory) pollutants. Several oxidation methods have been developed for their degradation, the most efficient of which is irradiation treatment, particularly that based on e-beam processing in the presence of O 2 /O 3 . The next-best method is photoinduced pollutant oxidation with VUV- and/or UV-light, using H 2 O 2 or H 2 O 2 /O 3 as an additional source of OH radicals. The photocatalytic method, using e.g. TiO 2 as a catalyst in combination with oxidation agents such as H 2 O 2 or H 2 O 2 /O 3 , is also recommended. The suitability of these three methods is illustrated by examples and they are briefly discussed and compared on the basis of the energy consumption and efficiency. Other methods, such as ozone treatment, the photo-Fenton process, ultrasonic and electrochemical treatments, as well as the well known biological process and thermal oxidation of refractory pollutants, are briefly mentioned. (author)

  16. 3. International conference on oxidation technologies for water and wastewater treatment. Special topic: AOP's for recycling and reuse

    Energy Technology Data Exchange (ETDEWEB)

    Vogelpohl, A. (ed.)

    2003-07-01

    With the increasing pressure on a more effective and sustainable use of water resources, those water treatment technologies become more and more important which will allow for a recycling of wastewater for agricultural and/or industrial purposes. The so-called advanced oxidation processes (AOP's) belong to these technologies as they offer the potential of a complete conversion of the water pollutants to carbon dioxide, water and mineral salts. Despite the progress that has been achieved in understanding and applying AOP's, the most significant disadvantages of the oxidation technologies are the high investment and operating costs. As these technologies are the high investment and operating costs. As these technologies are based on radical reactions, more effective means of producing radicals and a deeper insight in the reaction pathways will be the key for generating radicals at lower costs as well as choosing the optimum process conditions and defining the applications where AOP's are most competitive. Two national, three international conferences with the publication of their papers in water science and technology (1997 and 2001) as well as the foundation of the IWA Specialist Group on AOP's in 2001 demonstrate the success and the necessity of this conference series. It is designed to bring forward the most recent advances in the fundamentals as well as the development and the application of AOP's especially in the field of water recycling reuse. It will help to disseminate new achievements in these areas and to identify future research and development needs. The increased number of interesting papers submitted will be the basis for a successful, fruitful and hopefully critical conference in Goslar. (orig.)

  17. Treatment of high salt oxidized modified starch waste water using micro-electrolysis, two-phase anaerobic aerobic and electrolysis for reuse

    Science.gov (United States)

    Yi, Xuenong; Wang, Yulin

    2017-06-01

    A combined process of micro-electrolysis, two-phase anaerobic, aerobic and electrolysis was investigated for the treatment of oxidized modified starch wastewater (OMSW). Optimum ranges for important operating variables were experimentally determined and the treated water was tested for reuse in the production process of corn starch. The optimum hydraulic retention time (HRT) of micro-electrolysis, methanation reactor, aerobic process and electrolysis process were 5, 24, 12 and 3 h, respectively. The addition of iron-carbon fillers to the acidification reactor was 200 mg/L while the best current density of electrolysis was 300 A/m2. The biodegradability was improved from 0.12 to 0.34 by micro-electrolysis. The whole treatment was found to be effective with removal of 96 % of the chemical oxygen demand (COD), 0.71 L/day of methane energy recovery. In addition, active chlorine production (15,720 mg/L) was obtained by electrolysis. The advantage of this hybrid process is that, through appropriate control of reaction conditions, effect from high concentration of salt on the treatment was avoided. Moreover, the process also produced the material needed in the production of oxidized starch while remaining emission-free and solved the problem of high process cost.

  18. Treatment of refractory organic pollutants in industrial wastewater by wet air oxidation

    Directory of Open Access Journals (Sweden)

    Mingming Luan

    2017-02-01

    Full Text Available Wet air oxidation (WAO is one of the most economical and environmentally-friendly advanced oxidation processes. It makes a promising technology for the treatment of refractory organic pollutants in industrial wastewaters. In wet air oxidation aqueous waste is oxidized in the liquid phase at high temperatures (125–320 °C and pressures (0.5–20 MPa in the presence of an oxygen-containing gas (usually air. The advantages of the process include low operating costs and minimal air pollution discharges. The present review is concerned about the literature published in the treatment of refractory organic pollutants in industrial wastewaters, such as dyes. Phenolics were taken as model pollutants in most cases. Reports on effect of treatment for the WAO of refractory organic pollutants in industrial wastewaters are reviewed, such as emulsified wastewater, TNT red water, etc. Discussions are also made on the mechanism and kinetics of WAO and main technical parameters influencing WAO. Finally, development direction of WAO is summed up.

  19. Water oxidation catalysts and methods of use thereof

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Craig L.; Gueletii, Yurii V.; Musaev, Djamaladdin G.; Yin, Qiushi; Botar, Bogdan

    2017-12-05

    Homogeneous water oxidation catalysts (WOCs) for the oxidation of water to produce hydrogen ions and oxygen, and methods of making and using thereof are described herein. In a preferred embodiment, the WOC is a polyoxometalate WOC which is hydrolytically stable, oxidatively stable, and thermally stable. The WOC oxidized waters in the presence of an oxidant. The oxidant can be generated photochemically, using light, such as sunlight, or electrochemically using a positively biased electrode. The hydrogen ions are subsequently reduced to form hydrogen gas, for example, using a hydrogen evolution catalyst (HEC). The hydrogen gas can be used as a fuel in combustion reactions and/or in hydrogen fuel cells. The catalysts described herein exhibit higher turn over numbers, faster turn over frequencies, and/or higher oxygen yields than prior art catalysts.

  20. Comparative studies of MOS-gate/oxide-passivated AlGaAs/InGaAs pHEMTs by using ozone water oxidation technique

    International Nuclear Information System (INIS)

    Lee, Ching-Sung; Hung, Chun-Tse; Chou, Bo-Yi; Hsu, Wei-Chou; Liu, Han-Yin; Ho, Chiu-Sheng; Lai, Ying-Nan

    2012-01-01

    Al 0.22 Ga 0.78 As/In 0.24 Ga 0.76 As pseudomorphic high-electron-mobility transistors (pHEMTs) with metal-oxide-semiconductor (MOS)-gate structure or oxide passivation by using ozone water oxidation treatment have been comprehensively investigated. Annihilated surface states, enhanced gate insulating property and improved device gain have been achieved by the devised MOS-gate structure and oxide passivation. The present MOS-gated or oxide-passivated pHEMTs have demonstrated superior device performances, including superior breakdown, device gain, noise figure, high-frequency characteristics and power performance. Temperature-dependent device characteristics of the present designs at 300–450 K are also studied. (paper)

  1. Rapid Evaporation of Water on Graphene/Graphene-Oxide: A Molecular Dynamics Study.

    Science.gov (United States)

    Li, Qibin; Xiao, Yitian; Shi, Xiaoyang; Song, Shufeng

    2017-09-07

    To reveal the mechanism of energy storage in the water/graphene system and water/grapheme-oxide system, the processes of rapid evaporation of water molecules on the sheets of graphene and graphene-oxide are investigated by molecular dynamics simulations. The results show that both the water/graphene and water/grapheme-oxide systems can store more energy than the pure water system during evaporation. The hydroxyl groups on the surface of graphene-oxide are able to reduce the attractive interactions between water molecules and the sheet of graphene-oxide. Also, the radial distribution function of the oxygen atom indicates that the hydroxyl groups affect the arrangement of water molecules at the water/graphene-oxide interface. Therefore, the capacity of thermal energy storage of the water/graphene-oxide system is lower than that of the water/graphene system, because of less desorption energy at the water/graphene-oxide interface. Also, the evaporation rate of water molecules on the graphene-oxide sheet is slower than that on the graphene sheet. The Leidenfrost phenomenon can be observed during the evaporation process in the water/grapheme-oxide system.

  2. Bacterial Diversity in a Mine Water Treatment Plant▿ †

    OpenAIRE

    Heinzel, Elke; Hedrich, Sabrina; Janneck, Eberhard; Glombitza, Franz; Seifert, Jana; Schlömann, Michael

    2008-01-01

    We investigated the microbial community in a pilot plant for treatment of acid mine water by biological ferrous iron oxidation using clone library analysis and calculated statistical parameters for further characterization. The microbial community in the plant was conspicuously dominated by a group of Betaproteobacteria affiliated with “Ferribacter polymyxa”.

  3. A field demonstration of the microbial treatment of sour produced water

    Energy Technology Data Exchange (ETDEWEB)

    Sublette, K.L. [Univ. of Tulsa, OK (United States); Morse, D.; Raterman, K. [Amoco Production Co., Tulsa, OK (United States)

    1995-12-31

    The potential for detoxification and deodorization of sulfide-laden water (sour water) by microbial treatment was evaluated at a petroleum production site under field conditions. A sulfide-tolerant strain of the chemautotroph and facultative anaerobe, Thiobacillus denitrificans, was introduced into an oil-skimming pit of the Amoco Production Company LACT 10 Unit of the Salt Creek Field, Wyoming. Field-produced water enters this pit from the oil/water separation treatment train at an average flowrate of 5,000 bbl/D (795 m{sup 3}/D) with a potential maximum of 98,000 bbl/D (15,580 m{sup 3}/D). Water conditions at the pit inlet are 4,800 mg/l TDS, 100 mg/l sulfide, pH 7.8, and 107{degrees}F. To this water an aqueous solution of ammonium nitrate and diphosphorous pentoxide was added to provide required nutrients for the bacteria. The first 20% of the pit was aerated to a maximum depth of 5 ft (1.5 m) to facilitate the aerobic oxidation of sulfide. No provisions for pH control or biomass recovery and recycle were made. Pilot operations were initiated in October 1992 with the inoculation of the 19,000 bbl (3,020 m{sup 3}) pit with 40 lb (18.1 kg) of dry weight biomass. After a brief acclimation period, a nearly constant mass flux of 175 lb/D (80 kg/D) sulfide was established to the pit. Bio-oxidation of sulfide to elemental sulfur and sulfate was immediate and complete. Subsequent pilot operations focused upon process optimization and process sensitivity to system upsets. The process appeared most sensitive to large variations in sulfide loading due to maximum water discharge events. However, recoveries from such events could be accomplished within hours. This paper details all pertinent aspects of pilot operation, performance, and economics. Based on this body of evidence, it is suggested that the oxidation of inorganic sulfides by T denitrificans represents a viable concept for the treatment of sour water coproduced with oil and gas.

  4. Oxidation by UV and ozone of organic contaminants dissolved in deionized and raw mains water

    International Nuclear Information System (INIS)

    Francis, P.D.

    1987-01-01

    Organic contaminants dissolved in deionized pretreated and raw mains water were reacted with ultraviolet light and ozone. Ozone first was used for partial oxidation followed by ozone combined with ultraviolet radiation to produce total oxidation. The reduction of total organic carbon (TOC) level and direct oxidation of halogenated compounds were measured throughout the treatment process. The rate of TOC reduction was compared for ozone injected upstream and inside the reactor

  5. Supercritical Water Oxidation Total Organic Carbon (TOC) Analysis

    Science.gov (United States)

    The work presented here is the evaluation of the modified wet‐oxidation method described as Supercritical Water Oxidation (SCWO) for the analysis of total organic carbon (TOC) in very difficult oil/gas produced water sample matrices.

  6. Effects of water turbidity and different temperatures on oxidative stress in caddisfly (Stenopsyche marmorata) larvae.

    Science.gov (United States)

    Suzuki, Jumpei; Imamura, Masahiro; Nakano, Daisuke; Yamamoto, Ryosuke; Fujita, Masafumi

    2018-07-15

    Anthropogenic water turbidity derived from suspended solids (SS) is caused by reservoir sediment management practices such as drawdown flushing. Turbid water induces stress in many aquatic organisms, but the effects of turbidity on oxidative stress responses in aquatic insects have not yet been demonstrated. Here, we examined antioxidant responses, oxidative damage, and energy reserves in caddisfly (Stenopsyche marmorata) larvae exposed to turbid water (0 mg SS L -1 , 500 mg SS L -1 , and 2000 mg SS L -1 ) at different temperatures. We evaluated the combined effects of turbid water and temperature by measuring oxidative stress and using metabolic biomarkers. No turbidity level was significantly lethal to S. marmorata larvae. Moreover, there were no significant differences in antioxidant response or oxidative damage between the control and turbid water treatments at a low temperature (10 °C). However, at a high temperature (25 °C), turbid water modulated the activity of the antioxidant enzymes superoxide dismutase and catalase and the oxygen radical absorbance capacity as an indicator of the redox state of the insect larvae. Antioxidant defenses require energy, and high temperature was associated with low energy reserves, which might limit the capability of organisms to counteract reactive oxygen species. Moreover, co-exposure to turbid water and high temperature caused fluctuation of antioxidant defenses and increased the oxidative damage caused by the production of reactive oxygen species. Furthermore, the combined effect of high temperature and turbid water on antioxidant defenses and oxidative damage was larger than the individual effects. Therefore, our results demonstrate that exposure to both turbid water and high temperature generates additive and synergistic interactions causing oxidative stress in this aquatic insect species. Copyright © 2018. Published by Elsevier B.V.

  7. Removal of the cyanotoxin anatoxin-a by drinking water treatment processes: a review.

    Science.gov (United States)

    Vlad, Silvia; Anderson, William B; Peldszus, Sigrid; Huck, Peter M

    2014-12-01

    Anatoxin-a (ANTX-a) is a potent alkaloid neurotoxin, produced by several species of cyanobacteria and detected throughout the world. The presence of cyanotoxins, including ANTX-a, in drinking water sources is a potential risk to public health. This article presents a thorough examination of the cumulative body of research on the use of drinking water treatment technologies for extracellular ANTX-a removal, focusing on providing an analysis of the specific operating parameters required for effective treatment and on compiling a series of best-practice recommendations for owners and operators of systems impacted by this cyanotoxin. Of the oxidants used in drinking water treatment, chlorine-based processes (chlorine, chloramines and chlorine dioxide) have been shown to be ineffective for ANTX-a treatment, while ozone, advanced oxidation processes and permanganate can be successful. High-pressure membrane filtration (nanofiltration and reverse osmosis) is likely effective, while adsorption and biofiltration may be effective but further investigation into the implementation of these processes is necessary. Given the lack of full-scale verification, a multiple-barrier approach is recommended, employing a combination of chemical and non-chemical processes.

  8. STUDY ON WATER QUALITY INDICATORS AT TAIA TREATMENT PLANT HUNDEDOARA COUNTY

    Directory of Open Access Journals (Sweden)

    Ramona Violeta CAZALBAŞU

    2017-05-01

    Full Text Available Water is consumed in its natural form or in a processed one. It is a well-known fact that enterprises, institutions, energy and agriculture consume it as processed water whereas the population consumes it as drinking water or wastewater. This paper presents the study of water quality indicators from the treatment plant Taia in Hunedoara County. The following quality indicators were determined: turbidity, hardness, alkalinity, chlorine oxide and organic substances. The determined quality indicators revealed that they fall within the limits set by legislation, with some exceptions. In each step of purification of organic substances there has been a continual reduction, this being carried out both biologically because of the biomass deposited on sand grains in the filter bed as well as especially during the oxidation step with active chlorine

  9. Mine Water Treatment in Hongai Coal Mines

    Science.gov (United States)

    Dang, Phuong Thao; Dang, Vu Chi

    2018-03-01

    Acid mine drainage (AMD) is recognized as one of the most serious environmental problem associated with mining industry. Acid water, also known as acid mine drainage forms when iron sulfide minerals found in the rock of coal seams are exposed to oxidizing conditions in coal mining. Until 2009, mine drainage in Hongai coal mines was not treated, leading to harmful effects on humans, animals and aquatic ecosystem. This report has examined acid mine drainage problem and techniques for acid mine drainage treatment in Hongai coal mines. In addition, selection and criteria for the design of the treatment systems have been presented.

  10. Some research aspects for irradiation treatment of the polluted waters in China

    International Nuclear Information System (INIS)

    Yang Jingtian; Yun Guichun; Ha Hongfei

    1988-01-01

    This paper is a review of some aspects of research work on radiation treatment of surface and industrial polluted waters in China. These studies include: radiation-oxidized decomposition of phenols, cyanides and pesticides etc., radiation decolourization of wastewater from dyeworks, radiation modification of the biodegradability of saponificated wastewater as well as radiation sterilization of surface water, hospital sewage sludge, industrial cooling-water and water flooding in oil field. (author)

  11. Influence of drinking water treatments on chlorine dioxide consumption and chlorite/chlorate formation.

    Science.gov (United States)

    Sorlini, Sabrina; Gialdini, Francesca; Biasibetti, Michela; Collivignarelli, Carlo

    2014-05-01

    Disinfection is the last treatment stage of a Drinking Water Treatment Plant (DWTP) and is carried out to maintain a residual concentration of disinfectant in the water distribution system. Chlorine dioxide (ClO2) is a widely used chemical employed for this purpose. The aim of this work was to evaluate the influence of several treatments on chlorine dioxide consumption and on chlorite and chlorate formation in the final oxidation/disinfection stage. A number of tests was performed at laboratory scale employing water samples collected from the DWTP of Cremona (Italy). The following processes were studied: oxidation with potassium permanganate, chlorine dioxide and sodium hypochlorite, coagulation/flocculation with ferric chloride and aluminum sulfate, filtration and adsorption onto activated carbon. The results showed that the chlorine dioxide demand is high if sodium hypochlorite or potassium permanganate are employed in pre-oxidation. On the other hand, chlorine dioxide leads to the highest production of chlorite and chlorate. The coagulation/flocculation process after pre-oxidation shows that chlorine dioxide demand decreases if potassium permanganate is employed as an oxidant, both with ferric chloride and aluminum sulfate. Therefore, the combination of these processes leads to a lower production of chlorite and chlorate. Aluminum sulfate is preferable in terms of the chlorine dioxide demand reduction and minimization of the chlorite and chlorate formation. Activated carbon is the most effective solution as it reduced the chlorine dioxide consumption by about 50% and the DBP formation by about 20-40%. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Effect of hydraulic retention time on ABR tail water treatment by contact oxidation process under low oxygen condition

    Science.gov (United States)

    Huang, Xiaolong; Shi, Chunhong; Wang, Zhenbao; Jiang, Kai

    2018-02-01

    Biological contact oxidation process of low dissolved oxygen was applied to the treatment of ABR tail water, which were pretreatment effluent for Island sewage. The reactor was built and filled with polyurethane suspension filler as carrier for biofilm growth in laboratory. The dissolved oxygen in the reactor is kept at 1.3-1.8mg/L to distinguish between traditional method which is 2.5-3.5mg/L. Influence of hydraulic retention time(HRT) on ABR tail water treatment by the process was studied. Results show that the system has good effect on removal of COD and TN under this condition. When HRT is among 4h to 12h, the removal rate of COD can be maintained at 80-90%.From period 1 to period 3, the removal rate of NH4 +N and TN at the end of each period can be recovered to a higher level, and the average removal rate after stabilization is 99% and 67% respectively which can come up to first grade of the national standard GB18918-2002. It is remarkable that when HRT is 4h, the removal rate of NH4 +-N and TN showed a significant decrease trend, the concentration of effluent was 14.79mg/L and 19.5mg/L, respectively.

  13. Preliminary radiation-oxidizing treatment influence on radiation-catalytic activity of zirconium during water decomposition process

    International Nuclear Information System (INIS)

    Garibov, A.A.; Aliyev, A.G.; Agayev, T.N.; Aliyev, S.M.; Velibekova, G.Z.

    2004-01-01

    The study of physical-chemical processes proceeding in contact of metal constructional materials nuclear reactors with water at simultaneous influence of temperature and radiation represents the large interest at the decision of problems material authority and safety of work of nuclear -power installations [1-2]. One of the widely widespread materials of active zone nuclear reactors is metal zirconium and its alloys. The influence of preliminary radiation processing on radiation, radiation -thermal and thermal processes of accumulation of molecular hydrogen and oxidation zirconium in contact with water is investigated at T=673 K and ρ=5mg/sm 3 [3-4]. Initial samples zirconium previously has been exposed by an irradiation in medium H 2 O 2 at D=20-410 kGy. The contribution of radiation processes in these contacts in process thermo-radiation decomposition of water and oxidation of materials of zirconium is revealed. It is established that the interaction of Zr metal, preliminary treated by radiation, with water at radiation -heterogeneous processes leads to passivity of a surface. The rate meanings of thermal, radiation -thermal processes and radiation-chemical yields of hydrogen are determined. It is revealed, that at radiation-heterogeneous processes in system Zr +H 2 O (ρ =5mg/sm 3 T=673 K) the increase of the absorbed doze up to 123 kGy results to reduction of a radiation -chemical yield of molecular hydrogen. The further increase of the absorbed doze results to increase of a radiation -chemical yield of hydrogen. The observable effect at the preliminary radiation of zirconium is connected to formation of oxide phase on a surface. The mechanism of radiation -heterogeneous processes proceeding in system Zr+H 2 O is suggested. (author)

  14. Hydrogen-water deuterium exchange over metal oxide promoted nickel catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Sagert, N H; Shaw-Wood, P E; Pouteau, R M.L. [Atomic Energy of Canada Ltd., Pinawa, Manitoba. Whiteshell Nuclear Research Establishment

    1975-11-01

    Specific rates have been measured for hydrogen-water deuterium isotope exchange over unsupported nickel promoted with about 20% of various metal oxides. The oxides used were Cr/sub 2/O/sub 3/, MoO/sub 2/, MnO, WO/sub 2/-WO/sub 3/, and UO/sub 2/. Nickel surface areas, which are required to measure the specific rates, were determined by hydrogen chemisorption. Specific rates were measured as a function of temperature in the range 353 to 573 K and as a function of the partial pressure of hydrogen and water over a 10-fold range of partial pressure. The molybdenum and tungsten oxides gave the highest specific rates, and manganese and uranium oxides the lowest. Chromium oxide was intermediate, although it gave the highest rate per gram of catalyst. The orders with respect to hydrogen and water over molybdenum oxide and tungsten oxide promoted nickel were consistent with a mechanism in which nickel oxide is formed from the reaction of water with the catalyst, and then is reduced by hydrogen. Over manganese and uranium oxide promoted catalysts, these orders are consistent with a mechanism in which adsorbed water exchanges with chemisorbed hydrogen atoms on the nickel surface. Chromium oxide is intermediate. It was noted that those oxides which favored the nickel oxide route had electronic work functions closest to those of metallic nickel and nickel oxide.

  15. Combination of Advanced Oxidation Processes and biological treatments for wastewater decontamination-A review

    International Nuclear Information System (INIS)

    Oller, I.; Malato, S.; Sanchez-Perez, J.A.

    2011-01-01

    Nowadays there is a continuously increasing worldwide concern for development of alternative water reuse technologies, mainly focused on agriculture and industry. In this context, Advanced Oxidation Processes (AOPs) are considered a highly competitive water treatment technology for the removal of those organic pollutants not treatable by conventional techniques due to their high chemical stability and/or low biodegradability. Although chemical oxidation for complete mineralization is usually expensive, its combination with a biological treatment is widely reported to reduce operating costs. This paper reviews recent research combining AOPs (as a pre-treatment or post-treatment stage) and bioremediation technologies for the decontamination of a wide range of synthetic and real industrial wastewater. Special emphasis is also placed on recent studies and large-scale combination schemes developed in Mediterranean countries for non-biodegradable wastewater treatment and reuse. The main conclusions arrived at from the overall assessment of the literature are that more work needs to be done on degradation kinetics and reactor modeling of the combined process, and also dynamics of the initial attack on primary contaminants and intermediate species generation. Furthermore, better economic models must be developed to estimate how the cost of this combined process varies with specific industrial wastewater characteristics, the overall decontamination efficiency and the relative cost of the AOP versus biological treatment.

  16. Hydrogen Treatment and FeOOH overlayer: Effective approaches for enhancing the photoelectrochemical water oxidation performance of bismuth vanadate thin films

    DEFF Research Database (Denmark)

    Singh, Aadesh P.; Saini, Nishant; Mehta, Bodh R.

    2018-01-01

    The water oxidation capability of the promising photoanode bismuth vanadate (BiVO4) is hampered by poor bulk electron transport and by high rates of charge recombination at the semiconductor/electrolyte interface. Here, we demonstrate that a dual modification of BiVO4 by: (i) annealing in a hydro......The water oxidation capability of the promising photoanode bismuth vanadate (BiVO4) is hampered by poor bulk electron transport and by high rates of charge recombination at the semiconductor/electrolyte interface. Here, we demonstrate that a dual modification of BiVO4 by: (i) annealing...... modification strategy used here offers a simple but effective approach of improving the water oxidation performance of BiVO4....

  17. Effects of sonication and advanced chemical oxidants on the unicellular green alga Dunaliella tertiolecta and cysts, larvae and adults of the brine shrimp Artemia salina: a prospective treatment to eradicate invasive organisms from ballast water.

    Science.gov (United States)

    Gavand, Meghana R; McClintock, James B; Amsler, Charles D; Peters, Robert W; Angus, Robert A

    2007-11-01

    Uptake and release of ship-borne ballast water is a major factor contributing to introductions of aquatic phytoplankton and invasive macroinvertebrates. Some invasive unicellular algae can cause harmful algal blooms and produce toxins that build up in food chains. Moreover, to date, few studies have compared the efficacy of ballast water treatments against different life history phases of aquatic macroinvertebrates. In the present study, the unicellular green alga Dunaliella tertiolecta, and three discrete life history phases of the brine shrimp Artemia salina, were independently used as model organisms to study the efficacy of sonication as well as the advanced oxidants, hydrogen peroxide and ozone, as potential ballast water treatments. Algal cells and brine shrimp cysts, nauplii, and adults were subjected to individual and combined treatments of sonication and advanced oxidants. Combined rather than individual treatments consistently yielded the highest levels of mortality in algal cells (100% over a 2 min exposure) and in brine shrimp (100% and 95% for larvae and adults, respectively, over a 2 min exposure). In contrast, mortality levels in brine shrimp cysts (66% over 2 min; increased to 92% over a 20 min exposure) were moderately high but consistently lower than that detected for larval or adult shrimp. Our results indicate that a combination of sonication and advanced chemical oxidants may be a promising method to eradicate aquatic unicellular algae and macroinvertebrates in ballast water.

  18. Cuprous oxide created on sepiolite: Preparation, characterization, and photocatalytic activity in treatment of red water from 2,4,6-trinitrotoluene manufacturing

    International Nuclear Information System (INIS)

    Zhu, Qingwei; Zhang, Yihe; Lv, Fengzhu; Chu, Paul K.; Ye, Zhengfan; Zhou, Fengshan

    2012-01-01

    Highlights: ► Cu 2 O crystals were firstly created on the natural sepiolite fibers. ► The structures of the sepiolite are altered when acidized, benefiting the immobility of cuprous oxide crystals. ► The carrier sepiolite improves efficiently the photocatalytic activity of cuprous oxide crystals. ► Cu 2 O/sepiolite composites show superior photocatalytic activity for the degradation of red water. - Abstract: Cuprous oxide is firstly created on acidized sepiolite (AS) by a simple deposition method for photocatalytic degradation of the red water produced from 2,4,6-trinitrotoluene (TNT) manufacturing. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), ultraviolet-visible diffuse reflection absorptive spectroscopy (UV–vis/DRS), and Fourier transform infrared (FT-IR) spectroscopy are used to characterize the photocatalyst composites. Gas chromatography/mass spectrometry (GC/MS) is employed to determine the organic constituents in the red water. The results show that the cuprous oxide particles can be immobilized on the surface of the AS fibers and the structure of the AS is altered when cuprous oxide interacts with AS via chemical reactions besides physical adsorption. The AS improves the optical properties of cuprous oxide and red-shifts the band gap thereby enhancing the utilization of visible light. The Cu 2 O/AS composites demonstrate excellent photocatalytic performance in the degradation of red water. 87.0% of red water can be photocatalytically degraded by Cu 2 O/AS after illumined for 5 h and a majority of organic components of red water except 1,3,5-trinitrobenzene were degraded according to GC–MS analysis.

  19. New perspectives on the passive treatment of ferruginous circumneutral mine waters in the UK.

    Science.gov (United States)

    Sapsford, D J

    2013-11-01

    This paper examines major physico-chemical processes during the passive treatment of ferruginous circumneutral drainage from abandoned coal mines in the UK. Data collected over several years of studies on mine water treatment systems shed new light on the relative importance of hydraulics, settling velocity, Fe(II) oxidation rates and cascade aeration, which, in turn, informs the design of future systems. This paper demonstrates that (1) the complex settling behaviour of Fe(III) precipitates may be described by a first-order volumetric process and that settling rate is different for different mine waters; (2) the hydraulic efficiency (ratio of time to peak tracer concentration to nominal residence time) of the settling ponds studied was widely variable at low flow rates in comparison to constructed wetlands; (3) aeration cascades contribute dissolved oxygen and lead to a rise in pH due to CO2 degassing, which are very important in reducing the required time for iron oxidation and removal; (4) for at least 10 of the 30 sites examined, modelling of the rates of Fe(II) oxidation and particulate settling reveals that removal of iron is primarily dependent on settling rate; and (5) that substantial increases in pH can be brought about by forced aeration of mine water over several hours. Findings of this study apply to the majority of coal mine water treatment sites in the UK and may have broader application to other ferruginous waters with circumneutral pH or after treatment to increase pH.

  20. Anodic oxidation of InP in pure water

    International Nuclear Information System (INIS)

    Robach, Y.; Joseph, J.; Bergignat, E.; Hollinger, G.

    1989-01-01

    It is shown that thin InP native oxide films can be grown by anodization of InP in pure water. An interfacial phosphorus-rich In(PO 3 ) 3 -like condensed phosphate is obtained this way. This condensed phosphate has good passivating properties and can be used in electronic device technology. The chemical composition of these native oxides was found similar to that of an anodic oxide grown in an anodization in glycol and water (AGW) electrolyte. From the similarity between the two depth profiles observed in pure water and AGW electrolyte, they can conclude that dissolution phenomena do not seem to play a major role. The oxide growth seems to be controlled by the drift of ionic species under the electric field

  1. Biological water-oxidizing complex: a nano-sized manganese-calcium oxide in a protein environment.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Moghaddam, Atefeh Nemati; Yang, Young Nam; Aro, Eva-Mari; Carpentier, Robert; Eaton-Rye, Julian J; Lee, Choon-Hwan; Allakhverdiev, Suleyman I

    2012-10-01

    The resolution of Photosystem II (PS II) crystals has been improved using isolated PS II from the thermophilic cyanobacterium Thermosynechococcus vulcanus. The new 1.9 Å resolution data have provided detailed information on the structure of the water-oxidizing complex (Umena et al. Nature 473: 55-61, 2011). The atomic level structure of the manganese-calcium cluster is important for understanding the mechanism of water oxidation and to design an efficient catalyst for water oxidation in artificial photosynthetic systems. Here, we have briefly reviewed our knowledge of the structure and function of the cluster.

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

    Science.gov (United States)

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

    2017-07-16

    The paper presents a study on the treatment of the furniture industry wastewater in a bench scale advanced oxidation reactor. The researched technology utilized a simultaneous application of ozone, ultraviolet radiation and surface-immobilized TiO 2 nanoparticle catalyst. Various combinations of processes were tested, including photolysis, photocatalysis, ozonation, catalytic ozonation, photolytic ozonation and photocatalytic ozonation were tested against the efficiency of degradation. The efficiency of the processes was primarily characterized by the total organic carbon (TOC) analysis, indicating the remaining organic material in the wastewater after the treatment, while the toxicity changes in wastewater were researched by Daphnia magna toxicity tests. Photocatalytic ozonation was confirmed as the most effective combination of processes (99.3% of TOC reduction during 180 min of treatment), also being the most energy efficient (4.49-7.83 MJ/g). Photocatalytic ozonation and photolytic ozonation remained efficient across a wide range of pH (3-9), but the pH was an important factor in photocatalysis. The toxicity of wastewater depended on the duration of the treatment: half treated water was highly toxic, while fully treated water did not possess any toxicity. Our results indicate that photocatalytic ozonation has a high potential for the upscaling and application in industrial settings.

  3. Water Supply Treatment Sustainability of Panching Water Supply Treatment Process - Water Footprint Approach

    Science.gov (United States)

    Aziz, Edriyana A.; Malek, Marlinda Abdul; Moni, Syazwan N.; Zulkifli, Nabil F.; Hadi, Iqmal H.

    2018-03-01

    In many parts of the world, freshwater is scarce and overexploited. The purpose of this study is to determine the water footprint of Water Supply Treatment Process (WSTP) at Panching Water Treatment Plant (WTP) as well as to identify the sustainability of the Sg. Kuantan as an intake resource due to the effect of land use development. The total water footprint (WF) will be calculated by using WF accounting manual. The results obtained shows that the water intake resource is still available but it is believed that it will not be able to cope with the increasing WF. The increment of water demand percentage by 1.8% from 2015 to 2016 has increased 11 times higher of the water footprint percentage, 19.9%. This result shows that the water consumption during the water supply treatment process is two times higher than the demand thus it shows the inefficient of the water management

  4. Chemical oxidation of unsymmetrical dimethylhydrazine transformation products in water

    Directory of Open Access Journals (Sweden)

    Madi Abilev

    2015-03-01

    Full Text Available Oxidation of unsymmetrical dimethylhydrazine (UDMH during a water treatment has several disadvantages including formation of stable toxic byproducts. Effectiveness of treatment methods in relation to UDMH transformation products is currently poorly studied. This work considers the effectiveness of chemical oxidants in respect to main metabolites of UDMH – 1-formyl-2,2-dimethylhydrazine, dimethylaminoacetontrile, N-nitrosodimethylamine and 1-methyl-1H-1,2,4-triazole. Experiments on chemical oxidation by Fenton's reagent, potassium permanganate and sodium nitrite were conducted. Quantitative determination was performed by HPLC. Oxidation products were identified by gas chromatography-mass spectrometry in combination with solid-phase microextraction. 1-Formyl-2,2-dimethylhydrazine was completely oxidized by Fenton's reagent with formation of formaldehyde N-formyl-N-methyl-hydrazone, 1,4-dihydro-1,4-dimethyl-5H-tetrazol-5-one by the action of potassium permanganate and N-methyl-N-nitro-methanamine in the presence of sodium nitrite. Oxidation of 1-formyl-2,2-dimethylhydrazine also resulted in formation of N-nitrosodimethylamine. Oxidation of dimethylaminoacetontrile proceeded with formation of hydroxyacetonitrile, dimethylformamide and 1,2,5-trimethylpyrrole. After 30 days, dimethylaminoacetontrile was not detected in the presence of Fenton’s reagent and potassium permanganate, but it’s concentration in samples with sodium nitrite was 77.3 mg/L. In the presence of Fenton’s reagent, potassium permanganate and sodium nitrite after 30 days, N-nitrosodimethylamine concentration decreased by 85, 80 and 50%, respectively. In control sample, N-nitrosodimethylamine concentration decreased by 50%, indicating that sodium nitrite has no effect of on N-nitrosodimethylamine concentration. Only Fenton's reagent allowed to reduce the concentration of 1-methyl-1H-1,2,4-triazole to 50% in 30 days. In the presence of other oxidants, 1-methyl-1H-1,2,4-triazole

  5. Oxidative treatment of a waste water stream from a molasses processing using ozone and advanced oxidation technologies

    International Nuclear Information System (INIS)

    Gehringer, P.; Szinovatz, W.; Eschweiler, H.; Haberl, R.

    1994-08-01

    The discoloration of a biologically pretreated waste water stream from a molasses processing by ozonation and two advanced oxidation processes (O 3 /H 2 O 2 and O 3 /γ-irradiation, respectively) was studied. Colour removal occurred with all three processes with almost the same efficiency. The main difference of the methods applied was reflected by the BOD increase during the discoloration period. By ozonation it was much higher than by AOPs but it also appeared with AOPs. AOPs were, therefore, not apt for an effective BOD control during discoloration. (authors)

  6. Apatite Formation and Biocompatibility of a Low Young's Modulus Ti-Nb-Sn Alloy Treated with Anodic Oxidation and Hot Water.

    Directory of Open Access Journals (Sweden)

    Hidetatsu Tanaka

    Full Text Available Ti-6Al-4V alloy is widely prevalent as a material for orthopaedic implants because of its good corrosion resistance and biocompatibility. However, the discrepancy in Young's modulus between metal prosthesis and human cortical bone sometimes induces clinical problems, thigh pain and bone atrophy due to stress shielding. We designed a Ti-Nb-Sn alloy with a low Young's modulus to address problems of stress disproportion. In this study, we assessed effects of anodic oxidation with or without hot water treatment on the bone-bonding characteristics of a Ti-Nb-Sn alloy. We examined surface analyses and apatite formation by SEM micrographs, XPS and XRD analyses. We also evaluated biocompatibility in experimental animal models by measuring failure loads with a pull-out test and by quantitative histomorphometric analyses. By SEM, abundant apatite formation was observed on the surface of Ti-Nb-Sn alloy discs treated with anodic oxidation and hot water after incubation in Hank's solution. A strong peak of apatite formation was detected on the surface using XRD analyses. XPS analysis revealed an increase of the H2O fraction in O 1s XPS. Results of the pull-out test showed that the failure loads of Ti-Nb-Sn alloy rods treated with anodic oxidation and hot water was greater than those of untreated rods. Quantitative histomorphometric analyses indicated that anodic oxidation and hot water treatment induced higher new bone formation around the rods. Our findings indicate that Ti-Nb-Sn alloy treated with anodic oxidation and hot water showed greater capacity for apatite formation, stronger bone bonding and higher biocompatibility for osteosynthesis. Ti-Nb-Sn alloy treated with anodic oxidation and hot water treatment is a promising material for orthopaedic implants enabling higher osteosynthesis and lower stress disproportion.

  7. Mine Water Treatment in Hongai Coal Mines

    Directory of Open Access Journals (Sweden)

    Dang Phuong Thao

    2018-01-01

    Full Text Available Acid mine drainage (AMD is recognized as one of the most serious environmental problem associated with mining industry. Acid water, also known as acid mine drainage forms when iron sulfide minerals found in the rock of coal seams are exposed to oxidizing conditions in coal mining. Until 2009, mine drainage in Hongai coal mines was not treated, leading to harmful effects on humans, animals and aquatic ecosystem. This report has examined acid mine drainage problem and techniques for acid mine drainage treatment in Hongai coal mines. In addition, selection and criteria for the design of the treatment systems have been presented.

  8. Water Sorption and Gamma Radiolysis Studies for Uranium Oxides

    Energy Technology Data Exchange (ETDEWEB)

    Icenhour, A.S.

    2002-02-27

    During the development of a standard for the safe, long-term storage of {sup 233}U-containing materials, several areas were identified that needed additional experimental studies. These studies were related to the perceived potential for the radiolytic generation of large pressures or explosive concentrations of gases in storage containers. This report documents the results of studies on the sorption of water by various uranium oxides and on the gamma radiolysis of uranium oxides containing various amounts of sorbed moisture. In all of the experiments, {sup 238}U was used as a surrogate for the {sup 233}U. For the water sorption experiments, uranium oxide samples were prepared and exposed to known levels of humidity to establish the water uptake rate. Subsequently, the amount of water removed was studied by heating samples in a oven at fixed temperatures and by thermogravimetric analysis (TGA)/differential thermal analysis (DTA). It was demonstrated that heating at 650 C adequately removes all moisture from the samples. Uranium-238 oxides were irradiated in a {sup 60}Co source and in the high-gamma-radiation fields provided by spent nuclear fuel elements of the High Flux Isotope Reactor. For hydrated samples of UO{sub 3}, H{sub 2} was the primary gas produced; but the total gas pressure increase reached steady value of about 10 psi. This production appears to be a function of the dose and the amount of water present. Oxygen in the hydrated UO{sub 3} sample atmosphere was typically depleted, and no significant pressure rise was observed. Heat treatment of the UO{sub 3} {center_dot} xH{sub 2}O at 650 C would result in conversion to U{sub 3}O{sub 8} and eliminate the H{sub 2} production. For all of the U{sub 3}O{sub 8} samples loaded in air and irradiated with gamma radiation, a pressure decrease was seen and little, if any, H{sub 2} was produced--even for samples with up to 9 wt % moisture content. Hence, these results demonstrated that the efforts to remove trace

  9. Edge reactivity and water-assisted dissociation on cobalt oxide nanoislands

    International Nuclear Information System (INIS)

    Fester, J.; García-Melchor, M.; Walton, A. S.; Bajdich, M.

    2017-01-01

    Here, transition metal oxides show great promise as Earth-abundant catalysts for the oxygen evolution reaction in electrochemical water splitting. However, progress in the development of highly active oxide nanostructures is hampered by a lack of knowledge of the location and nature of the active sites. Here we show, through atom-resolved scanning tunnelling microscopy, X-ray spectroscopy and computational modelling, how hydroxyls form from water dissociation at under coordinated cobalt edge sites of cobalt oxide nanoislands. Surprisingly, we find that an additional water molecule acts to promote all the elementary steps of the dissociation process and subsequent hydrogen migration, revealing the important assisting role of a water molecule in its own dissociation process on a metal oxide. Inspired by the experimental findings, we theoretically model the oxygen evolution reaction activity of cobalt oxide nanoislands and show that the nanoparticle metal edges also display favourable adsorption energetics for water oxidation under electrochemical conditions.

  10. Superhydrophilic graphene oxide@electrospun cellulose nanofiber hybrid membrane for high-efficiency oil/water separation.

    Science.gov (United States)

    Ao, Chenghong; Yuan, Wei; Zhao, Jiangqi; He, Xu; Zhang, Xiaofang; Li, Qingye; Xia, Tian; Zhang, Wei; Lu, Canhui

    2017-11-01

    Inspired from fishscales, membranes with special surface wettability have been applied widely for the treatment of oily waste water. Herein, a novel superhydrophilic graphene oxide (GO)@electrospun cellulose nanofiber (CNF) membrane was successfully fabricated. This membrane exhibited a high separation efficiency, excellent antifouling properties, as well as a high flux for the gravity-driven oil/water separation. Moreover, the GO@CNF membrane was capable to effectively separate oil/water mixtures in a broad pH range or with a high concentration of salt, suggesting that this membrane was quite promising for future real-world practice in oil spill cleanup and oily wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Characterization of manganese oxide precipitates from Appalachian coal mine drainage treatment systems

    International Nuclear Information System (INIS)

    Tan Hui; Zhang Gengxin; Heaney, Peter J.; Webb, Samuel M.; Burgos, William D.

    2010-01-01

    The removal of Mn(II) from coal mine drainage (CMD) by chemical addition/active treatment can significantly increase treatment costs. Passive treatment for Mn removal involves promotion of biological oxidative precipitation of manganese oxides (MnO x ). Manganese(II) removal was studied in three passive treatment systems in western Pennsylvania that differed based on their influent Mn(II) concentrations (20-150 mg/L), system construction (±inoculation with patented Mn(II)-oxidizing bacteria), and bed materials (limestone vs. sandstone). Manganese(II) removal occurred at pH values as low as 5.0 and temperatures as low as 2 deg. C, but was enhanced at circumneutral pH and warmer temperatures. Trace metals such as Zn, Ni and Co were removed effectively, in most cases preferentially, into the MnO x precipitates. Based on synchrotron radiation X-ray diffraction and Mn K-edge extended X-ray absorption fine structure spectroscopy, the predominant Mn oxides at all sites were poorly crystalline hexagonal birnessite, triclinic birnessite and todorokite. The surface morphology of the MnO x precipitates from all sites was coarse and 'sponge-like' composed of nm-sized lathes and thin sheets. Based on scanning electron microscopy (SEM), MnO x precipitates were found in close proximity to both prokaryotic and eukaryotic organisms. The greatest removal efficiency of Mn(II) occurred at the one site with a higher pH in the bed and a higher influent total organic C (TOC) concentration (provided by an upstream wetland). Biological oxidation of Mn(II) driven by heterotrophic activity was most likely the predominant Mn removal mechanism in these systems. Influent water chemistry and Mn(II) oxidation kinetics affected the relative distribution of MnO x mineral assemblages in CMD treatment systems.

  12. Study on the bound water of several high specific surface-area oxides (beryllia, alumina, silica-alumina)

    International Nuclear Information System (INIS)

    Rouquerol, J.

    1964-11-01

    This study is concerned with the bound water of several oxides (beryllia, alumina, silica-alumina) at different steps of their dehydration (heating temperatures between 150 and 1100 deg. C). The following techniques have been used simultaneously: Thermal analysis (a new method has been developed), nitrogen adsorption (study of the texture), Diborane hydrolysis (qualitative and quantitative analysis of surface water), Infra-red spectrography (in the absorption range of water), Nuclear magnetic resonance (in the resonance range of protons). Thanks to these different techniques, five kinds of bound water have been observed. Attention is called on the great influence of the thermal treatment conditions on the evolution of the products resulting from the decomposition of alumina α-trihydrate Al(OH) 3 and beryllium α-hydroxide, in the course of the dehydration. Moreover, the author emphasizes the peculiar properties of the two kinds of oxides (alumina and beryllia) prepared through a new method of treatment under low pressure and constant speed of decomposition. Such particular features concern mainly texture, bound water, and consequently, also catalytic activity. (author) [fr

  13. Oxidant and antioxidant parameters in the treatment of meningitis.

    Science.gov (United States)

    Aycicek, Ali; Iscan, Akin; Erel, Ozcan; Akcali, Mustafa; Ocak, Ali Riza

    2007-08-01

    The aim of this study was to assess the effects of meningitis treatment on the serum and cerebrospinal-fluid oxidant and antioxidant status in children with bacterial meningitis. Forty children with bacterial meningitis, at ages ranging from 4 months to 12 years (mean age, 4 years), were enrolled in the study. Within 8 hours after admission (before treatment) and 10 days after clinical and laboratory indications of recovery (after treatment), cerebrospinal fluid and venous blood were collected. Thirty-seven healthy children (mean age, 4 years) were enrolled as control subjects, and only venous blood was collected. Serum total oxidant status, lipid hydroperoxide, oxidative stress index, uric acid, albumin, and ceruloplasmin levels were lower in the patient group after treatment (Ptotal antioxidant capacity levels, vitamin C, total bilirubin, and catalase concentrations were not significantly altered by treatment (P>0.05). However, cerebrospinal fluid total oxidant status, lipid hydroperoxide, and oxidative stress index levels were higher, and cerebrospinal fluid total antioxidant capacity levels were lower after treatment than before treatment (P<0.05). In conclusion, we demonstrated that serum oxidative stress was lower, and cerebrospinal fluid oxidative stress was higher, after rather than before treatment in children with bacterial meningitis.

  14. Effect of supplementation of water-soluble vitamins on oxidative stress and blood pressure in prehypertensives.

    Science.gov (United States)

    Talikoti, Prashanth; Bobby, Zachariah; Hamide, Abdoul

    2015-01-01

    The objective of the study was to evaluate the effect of water-soluble vitamins on oxidative stress and blood pressure in prehypertensives. Sixty prehypertensives were recruited and randomized into 2 groups of 30 each. One group received water-soluble vitamins and the other placebo for 4 months. Further increase in blood pressure was not observed in the vitamin group which increased significantly in the placebo group at the end of 4 months. Malonedialdehyde and protein carbonylation were reduced during the course of treatment with vitamins whereas in the placebo group there was an increase in the level of malondialdehyde. In conclusion, supplementation of water-soluble vitamins in prehypertension reduces oxidative stress and its progression to hypertension.

  15. A comparative view of radiation, photo and photocatalytically induced oxidation of water pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Getoff, N [Institute for Theoretical Chemistry and Radiation Chemistry, Univ. of Vienna, Vienna (Austria)

    1997-10-01

    Water resources are presently overloaded with biologically resistant (refractory) pollutants. Several oxidation methods have been developed for their degradation, the most efficient of which is irradiation treatment, particularly that based on e-beam processing in the presence of O{sub 2}/O{sub 3}. The next-best method is photoinduced pollutant oxidation with VUV- and/or UV-light, using H{sub 2}O{sub 2} or H{sub 2}O{sub 2}/O{sub 3} as an additional source of OH radicals. The photocatalytic method, using e.g. TiO{sub 2} as a catalyst in combination with oxidation agents such as H{sub 2}O{sub 2} or H{sub 2}O{sub 2}/O{sub 3}, is also recommended. The suitability of these three methods is illustrated by examples and they are briefly discussed and compared on the basis of the energy consumption and efficiency. Other methods, such as ozone treatment, the photo-Fenton process, ultrasonic and electrochemical treatments, as well as the well known biological process and thermal oxidation of refractory pollutants, are briefly mentioned. (author). 36 refs, 9 figs, 3 tabs.

  16. Chemical oxidation methods in the closure of paper mill water circulations; Hapetustekniikoiden kaeyttoe metsaeteollisuuden vesikiertojen sulkemisessa - EKT 04

    Energy Technology Data Exchange (ETDEWEB)

    Laari, A.; Kallas, J. [Lappeenranta Univ. of Technology (Finland); Korhonen, S. [Kuopio Univ. (Finland); Tuhkanen, T. [Mikkelin Ammattikorkeakoulu, Mikkeli (Finland)

    1998-12-31

    When water circulations are closed some harmful compounds tend to accumulate in the circulation waters. These compounds include lipophilic extractives, like resin and fatty acids, triglycerides and sterols, but also other compounds, like lignins, lignans and sugars. Microbial growth will increase due to elevated organic concentrations. The purpose of this project is to find out the possibilities of the use of ozonation and wet oxidation in the treatment of paper mill water circulations. In chemical oxidation organic matter is destroyed in oxidation reactions. Especially lipophilic extractives are selectively oxidated by ozone. Chemical oxidation reactions are carried out in gas-liquid reactors, where ozone or oxygen are transferred from gas to liquid phase where the oxidation reactions happen. One target of the project is to estimate kinetic parameters for different groups of compounds on the basis of experimental data. Kinetic parameters are then used in modelling of reactors and in estimation of process costs. (orig.)

  17. Chemical oxidation methods in the closure of paper mill water circulations; Hapetustekniikoiden kaeyttoe metsaeteollisuuden vesikiertojen sulkemisessa - EKT 04

    Energy Technology Data Exchange (ETDEWEB)

    Laari, A; Kallas, J [Lappeenranta Univ. of Technology (Finland); Korhonen, S [Kuopio Univ. (Finland); Tuhkanen, T [Mikkelin Ammattikorkeakoulu, Mikkeli (Finland)

    1999-12-31

    When water circulations are closed some harmful compounds tend to accumulate in the circulation waters. These compounds include lipophilic extractives, like resin and fatty acids, triglycerides and sterols, but also other compounds, like lignins, lignans and sugars. Microbial growth will increase due to elevated organic concentrations. The purpose of this project is to find out the possibilities of the use of ozonation and wet oxidation in the treatment of paper mill water circulations. In chemical oxidation organic matter is destroyed in oxidation reactions. Especially lipophilic extractives are selectively oxidated by ozone. Chemical oxidation reactions are carried out in gas-liquid reactors, where ozone or oxygen are transferred from gas to liquid phase where the oxidation reactions happen. One target of the project is to estimate kinetic parameters for different groups of compounds on the basis of experimental data. Kinetic parameters are then used in modelling of reactors and in estimation of process costs. (orig.)

  18. Supercritical water oxidation of ion exchange resins: Degradation mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Leybros, A.; Roubaud, A. [CEA Marcoule, DEN DTCD SPDE LFSM, F-30207 Bagnols Sur Ceze (France); Guichardon, P. [Ecole Cent Marseille, F-13451 Marseille 20 (France); Boutin, O. [Aix Marseille Univ, UMR CNRS 6181, F-13545 Aix En Provence 4 (France)

    2010-07-01

    Spent ion exchange resins are radioactive process wastes for which there is no satisfactory industrial treatment. Supercritical water oxidation could offer a viable treatment alternative to destroy the organic structure of resins and contain radioactivity. IER degradation experiments were carried out in a continuous supercritical water reactor. Total organic carbon degradation rates in the range of 95-98% were obtained depending on operating conditions. GC-MS chromatography analyses were carried out to determine intermediate products formed during the reaction. Around 50 species were identified for cationic and anionic resins. Degradation of poly-styrenic structure leads to the formation of low molecular weight compounds. Benzoic acid, phenol and acetic acid are the main compounds. However, other products are detected in appreciable yields such as phenolic species or heterocycles, for anionic IERs degradation. Intermediates produced by intramolecular rearrangements are also obtained. A radical degradation mechanism is proposed for each resin. In this overall mechanism, several hypotheses are foreseen, according to HOO center dot radical attack sites. (authors)

  19. Membrane chemical reactor (MCR) combining photocatalysis and microfiltration for grey water treatment.

    Science.gov (United States)

    Rivero, M J; Parsons, S A; Jeffrey, P; Pidou, M; Jefferson, B

    2006-01-01

    Urban water recycling is now becoming an important issue where water resources are becoming scarce. This paper looks at reusing grey water; the preference is treatment processes based on biological systems to remove the dissolved organic content. Here, an alternative process, photocatalysis is discussed as it is an attractive technology that could be well-suited for treating the recalcitrant organic compounds found in grey water. The photocatalytic process oxidises organic reactants at a catalyst surface in the presence of ultraviolet light. Given enough exposure time, organic compounds will be oxidized into CO2 and water. The best contact is achieved in a slurry reactor but a second step to separate and recover the catalyst is need. This paper discusses a new membrane chemical reactor (MCR) combining photocatalysis and microfiltration for grey water treatment.

  20. Oxidation and photo-oxidation of water on TiO2 surface

    DEFF Research Database (Denmark)

    Valdes, A.; Qu, Z.W.; Kroes, G.J.

    2008-01-01

    The oxidation and photo-oxidation of water on the rutile TiO2(110) surface is investigated using density functional theory (DFT) calculations. We investigate the relative stability of different surface terminations of TiO2 interacting with H2O and analyze the overpotential needed for the electrol...

  1. The state-of-the art of produced water treatment by oxidative advanced processes; Atual estagio de desenvolvimento dos processos oxidativos avancados para o tratamento da agua produzida

    Energy Technology Data Exchange (ETDEWEB)

    Cortes, Marcela de A.H.; Marques, Jose Jailton; Rocha, Inaura C.C. da [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil). Dept. de Engenharia Quimica

    2008-07-01

    The oily wastewater generated in petroleum exploration contains a sort of contaminants that may cause significant environmental impact. For this reason, the number of researchers that are looking for cleaner techniques to treat this kind of wastewater is growing. The advanced oxidation processes (AOPs) are clean and non-selective processes largely used to the treatment of wastewater containing critical substances like textile dyes, pesticides, PCBs, PAHs etc. The treatment systems using AOPs can be homogeneous or heterogeneous and they may use irradiation or not. This work presents a compilation of the results found by many researchers involving AOPs potentially applicable to the treatment of produced water, as follow: H{sub 2}O{sub 2}/UV, H{sub 2}O{sub 2} / Fe{sup 2+} / UV, O{sub 3}/UV, O{sub 3}/ H{sub 2}O{sub 2} etc., showing the state-of-art of oxidation advanced processes. (author)

  2. Potential exposure and treatment efficiency of nanoparticles in water supplies based on wastewater reclamation

    DEFF Research Database (Denmark)

    Kirkegaard, Peter; Hansen, Steffen Foss; Rygaard, Martin

    2015-01-01

    Water scarcity brings an increased focus on wastewater reclamation for drinking water supply. Meanwhile, the production volume of nanoparticles (NPs) is rapidly increasing, but to date there has been little attention given to the fate of NPs in water systems based on wastewater reclamation. We have...... investigated the possible concentrations of silver (Ag), titanium dioxide (TiO2), and zinc oxide (ZnO) nanoparticles in tap water for water supplies based on reclaimed wastewater. Tap water concentrations of the NPs were assessed by mass flow analyses of two typical wastewater reclamation concepts: 1) advanced...... studies are available on the removal efficiencies of NPs by advanced water treatment processes with a majority of the identified studies focusing on removal efficiencies in wastewater treatment plants and fate in surface waters. The NP removal efficiency of several treatment processes is unknown...

  3. Apatite Formation and Biocompatibility of a Low Young’s Modulus Ti-Nb-Sn Alloy Treated with Anodic Oxidation and Hot Water

    Science.gov (United States)

    Tanaka, Hidetatsu; Mori, Yu; Noro, Atsushi; Kogure, Atsushi; Kamimura, Masayuki; Yamada, Norikazu; Hanada, Shuji; Masahashi, Naoya; Itoi, Eiji

    2016-01-01

    Ti-6Al-4V alloy is widely prevalent as a material for orthopaedic implants because of its good corrosion resistance and biocompatibility. However, the discrepancy in Young’s modulus between metal prosthesis and human cortical bone sometimes induces clinical problems, thigh pain and bone atrophy due to stress shielding. We designed a Ti-Nb-Sn alloy with a low Young’s modulus to address problems of stress disproportion. In this study, we assessed effects of anodic oxidation with or without hot water treatment on the bone-bonding characteristics of a Ti-Nb-Sn alloy. We examined surface analyses and apatite formation by SEM micrographs, XPS and XRD analyses. We also evaluated biocompatibility in experimental animal models by measuring failure loads with a pull-out test and by quantitative histomorphometric analyses. By SEM, abundant apatite formation was observed on the surface of Ti-Nb-Sn alloy discs treated with anodic oxidation and hot water after incubation in Hank’s solution. A strong peak of apatite formation was detected on the surface using XRD analyses. XPS analysis revealed an increase of the H2O fraction in O 1s XPS. Results of the pull-out test showed that the failure loads of Ti-Nb-Sn alloy rods treated with anodic oxidation and hot water was greater than those of untreated rods. Quantitative histomorphometric analyses indicated that anodic oxidation and hot water treatment induced higher new bone formation around the rods. Our findings indicate that Ti-Nb-Sn alloy treated with anodic oxidation and hot water showed greater capacity for apatite formation, stronger bone bonding and higher biocompatibility for osteosynthesis. Ti-Nb-Sn alloy treated with anodic oxidation and hot water treatment is a promising material for orthopaedic implants enabling higher osteosynthesis and lower stress disproportion. PMID:26914329

  4. Supported graphene oxide hollow fibre membrane for oily wastewater treatment

    Science.gov (United States)

    Othman, Nur Hidayati; Alias, Nur Hashimah; Shahruddin, Munawar Zaman; Hussein, Siti Nurliyana Che Mohamed; Dollah, Aqilah

    2017-12-01

    Oil and gas industry deals with a large amount of undesirable discharges of liquid, solid, and gaseous wastes and the amounts can considerably change during the production phases. Oilfield wastewater or produced water is known to constitute various organic and inorganic components. Discharging the produced water can pollute surface and underground water and therefore the necessity to treat this oily wastewater is an inevitable challenge. The current technologies for the treatment of this metastable oil-in-water are not really effective and very pricey. As a result, there is a great interest from many parties around the world in finding cost-effective technologies. In recent years, membrane processes have been utilized for oily wastewater treatment. In these work, a graphene oxide membrane supported on a highly porous Al2O3 hollow fibre was prepared using vacuum assisted technique and its performance in treating oily wastewater was investigated. Graphene oxide (GO) was prepared using a modified Hummer's method and further characterized using XRD, FTIR, TGA and SEM. The results showed that the GO was successfully synthesized. The GO membrane was deposited on alumina hollow fibre substrates. The membrane performance was then investigated using dead-end filtration setup with synthetic oily wastewater as a feed. The effects of operating times on rejection rate and permeate flux were investigated. The experimental results showed that the oil rejections were over 90%. It was concluded that the supported GO membrane developed in this study may be considered feasible in treating oily wastewater. Detail study on the effects of transmembrane pressure, oil concentration, pH and fouling should be carried out in the future

  5. Energetic basis of catalytic activity of layered nanophase calcium manganese oxides for water oxidation.

    Science.gov (United States)

    Birkner, Nancy; Nayeri, Sara; Pashaei, Babak; Najafpour, Mohammad Mahdi; Casey, William H; Navrotsky, Alexandra

    2013-05-28

    Previous measurements show that calcium manganese oxide nanoparticles are better water oxidation catalysts than binary manganese oxides (Mn3O4, Mn2O3, and MnO2). The probable reasons for such enhancement involve a combination of factors: The calcium manganese oxide materials have a layered structure with considerable thermodynamic stability and a high surface area, their low surface energy suggests relatively loose binding of H2O on the internal and external surfaces, and they possess mixed-valent manganese with internal oxidation enthalpy independent of the Mn(3+)/Mn(4+) ratio and much smaller in magnitude than the Mn2O3-MnO2 couple. These factors enhance catalytic ability by providing easy access for solutes and water to active sites and facile electron transfer between manganese in different oxidation states.

  6. FLASH Technology: Full-Scale Hospital Waste Water Treatments Adopted in Aceh

    Science.gov (United States)

    Rame; Tridecima, Adeodata; Pranoto, Hadi; Moesliem; Miftahuddin

    2018-02-01

    A Hospital waste water contains a complex mixture of hazardous chemicals and harmful microbes, which can pose a threat to the environment and public health. Some efforts have been carried out in Nangroe Aceh Darussalam (Aceh), Indonesia with the objective of treating hospital waste water effluents on-site before its discharge. Flash technology uses physical and biological pre-treatment, followed by advanced oxidation process based on catalytic ozonation and followed by GAC and PAC filtration. Flash Full-Scale Hospital waste water Treatments in Aceh from different district have been adopted and investigated. Referring to the removal efficiency of macro-pollutants, the collected data demonstrate good removal efficiency of macro-pollutants using Flash technologies. In general, Flash technologies could be considered a solution to the problem of managing hospital waste water.

  7. Process water treatment in Canada's oil sands industry : 2 : a review of emerging technologies

    International Nuclear Information System (INIS)

    Allen, E.W.

    2008-01-01

    This review was conducted to identify candidate treatment technologies for treating oil sands process water. The oil sands industry in Canada uses large volumes of fresh water in order to extract bitumen deposits. The development of process water treatment technologies has become a critical issue for the industry, particularly as oil sand production is expected to triple in the next decade. However, treatment technologies must be adapted to consider the fouling potential of bitumens and fine clays as well as the effect of alkaline process water on treatment performance. The review included developments in chemical modifications to membranes and adsorbents designed to improve pollutant removal and reduce fouling; hybridization technologies designed to enhance the biological treatment of toxic feedwaters; recent advances in photocatalytic oxidation technologies for organic compounds; and new designs for large-scale treatment wetlands for polluted waste waters. It was concluded that major knowledge gaps must be optimized and preliminary studies must be conducted in order to understand how the treatment technologies will be affected by the chemical and physical characteristics of oil sands process water. 188 refs., 8 tabs

  8. Warm Water Oxidation Verification - Scoping and Stirred Reactor Tests

    Energy Technology Data Exchange (ETDEWEB)

    Braley, Jenifer C.; Sinkov, Sergey I.; Delegard, Calvin H.; Schmidt, Andrew J.

    2011-06-15

    Scoping tests to evaluate the effects of agitation and pH adjustment on simulant sludge agglomeration and uranium metal oxidation at {approx}95 C were performed under Test Instructions(a,b) and as per sections 5.1 and 5.2 of this Test Plan prepared by AREVA. (c) The thermal testing occurred during the week of October 4-9, 2010. The results are reported here. For this testing, two uranium-containing simulant sludge types were evaluated: (1) a full uranium-containing K West (KW) container sludge simulant consisting of nine predominant sludge components; (2) a 50:50 uranium-mole basis mixture of uraninite [U(IV)] and metaschoepite [U(VI)]. This scoping study was conducted in support of the Sludge Treatment Project (STP) Phase 2 technology evaluation for the treatment and packaging of K-Basin sludge. The STP is managed by CH2M Hill Plateau Remediation Company (CHPRC) for the U.S. Department of Energy. Warm water ({approx}95 C) oxidation of sludge, followed by immobilization, has been proposed by AREVA and is one of the alternative flowsheets being considered to convert uranium metal to UO{sub 2} and eliminate H{sub 2} generation during final sludge disposition. Preliminary assessments of warm water oxidation have been conducted, and several issues have been identified that can best be evaluated through laboratory testing. The scoping evaluation documented here was specifically focused on the issue of the potential formation of high strength sludge agglomerates at the proposed 95 C process operating temperature. Prior hydrothermal tests conducted at 185 C produced significant physiochemical changes to genuine sludge, including the formation of monolithic concretions/agglomerates that exhibited shear strengths in excess of 100 kPa (Delegard et al. 2007).

  9. Warm Water Oxidation Verification - Scoping and Stirred Reactor Tests

    International Nuclear Information System (INIS)

    Braley, Jenifer C.; Sinkov, Sergey I.; Delegard, Calvin H.; Schmidt, Andrew J.

    2011-01-01

    Scoping tests to evaluate the effects of agitation and pH adjustment on simulant sludge agglomeration and uranium metal oxidation at ∼95 C were performed under Test Instructions(a,b) and as per sections 5.1 and 5.2 of this Test Plan prepared by AREVA. (c) The thermal testing occurred during the week of October 4-9, 2010. The results are reported here. For this testing, two uranium-containing simulant sludge types were evaluated: (1) a full uranium-containing K West (KW) container sludge simulant consisting of nine predominant sludge components; (2) a 50:50 uranium-mole basis mixture of uraninite (U(IV)) and metaschoepite (U(VI)). This scoping study was conducted in support of the Sludge Treatment Project (STP) Phase 2 technology evaluation for the treatment and packaging of K-Basin sludge. The STP is managed by CH2M Hill Plateau Remediation Company (CHPRC) for the U.S. Department of Energy. Warm water (∼95 C) oxidation of sludge, followed by immobilization, has been proposed by AREVA and is one of the alternative flowsheets being considered to convert uranium metal to UO 2 and eliminate H 2 generation during final sludge disposition. Preliminary assessments of warm water oxidation have been conducted, and several issues have been identified that can best be evaluated through laboratory testing. The scoping evaluation documented here was specifically focused on the issue of the potential formation of high strength sludge agglomerates at the proposed 95 C process operating temperature. Prior hydrothermal tests conducted at 185 C produced significant physiochemical changes to genuine sludge, including the formation of monolithic concretions/agglomerates that exhibited shear strengths in excess of 100 kPa (Delegard et al. 2007).

  10. The importance of biological oxidation of iron in the aerobic cells of the Wheal Jane pilot passive treatment system.

    Science.gov (United States)

    Hall, G; Swash, P; Kotilainen, S

    2005-02-01

    The passive treatment system designed to treat the mine water discharge of the abandoned Wheal Jane tin mine in Cornwall consisted of a sequence of artificial wetland cells, an anaerobic cell and a final series of rock filters. Three systems were operated which differed only in the pre-treatment of the mine water before discharge to the aerobic wetland cells. The aerobic cells were designed to promote aerobic oxidation and precipitation of iron which could exceed a concentration of 100 mg/l in the raw mine water discharge. The largest investment of land area was to the artificial wetland cells and it was important to understand the processes of oxidation and precipitation of iron so that the performance of this aspect the pilot passive treatment plant (PPTP) could be managed as efficiently as possible. The generally low pH of the influent mine water and inevitable trend of decreasing pH due to hydrolysis of Fe(III) meant that distinguishing between biotic and abiotic mechanisms was fundamental for further design planning of passive treatment systems. This paper describes these observations.

  11. Water Treatment Group

    Data.gov (United States)

    Federal Laboratory Consortium — This team researches and designs desalination, water treatment, and wastewater treatment systems. These systems remediate water containing hazardous c hemicals and...

  12. Treatment of poly- and perfluoroalkyl substances in U.S. full-scale water treatment systems.

    Science.gov (United States)

    Appleman, Timothy D; Higgins, Christopher P; Quiñones, Oscar; Vanderford, Brett J; Kolstad, Chad; Zeigler-Holady, Janie C; Dickenson, Eric R V

    2014-03-15

    The near ubiquitous presence of poly- and perfluoroalkyl substances (PFASs) in humans has raised concerns about potential human health effects from these chemicals, some of which are both extremely persistent and bioaccumulative. Because some of these chemicals are highly water soluble, one major pathway for human exposure is the consumption of contaminated drinking water. This study measured concentrations of PFASs in 18 raw drinking water sources and 2 treated wastewater effluents and evaluated 15 full-scale treatment systems for the attenuation of PFASs in water treatment utilities throughout the U.S. A liquid-chromatography tandem mass-spectrometry method was used to enable measurement of a suite of 23 PFASs, including perfluorocarboxylic acids (PFCAs) and perfluorosulfonic acids (PFSAs). Despite the differences in reporting levels, the PFASs that were detected in >70% of the source water samples (n = 39) included PFSAs, perfluorobutane sulfonic acid (74%), perfluorohexane sulfonic acid (79%), and perfluorooctane sulfonic acid (84%), and PFCAs, perfluoropentanoic acid (74%), perfluorohexanoic acid (79%), perfluoroheptanoic acid (74%), and perfluorooctanoic acid (74%). More importantly, water treatment techniques such as ferric or alum coagulation, granular/micro-/ultra- filtration, aeration, oxidation (i.e., permanganate, ultraviolet/hydrogen peroxide), and disinfection (i.e., ozonation, chlorine dioxide, chlorination, and chloramination) were mostly ineffective in removing PFASs. However, anion exchange and granular activated carbon treatment preferably removed longer-chain PFASs and the PFSAs compared to the PFCAs, and reverse osmosis demonstrated significant removal for all the PFASs, including the smallest PFAS, perfluorobutanoic acid. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Advanced Heterogeneous Fenton Treatment of Coalbed Methane-Produced Water Containing Fracturing Fluid

    Directory of Open Access Journals (Sweden)

    Meng Zhang

    2018-04-01

    Full Text Available This study investigated the heterogeneous Fenton treatment to process coalbed methane-produced water containing fracturing fluid and chose the development region of coalbed methane in the Southern Qinshui Basin as a research area. We synthesized the catalyst of Fe-Co/γ-Al2O3 by homogeneous precipitation method and characterized it by BET, XRD, SEM-EDS, FTIR, and XPS. Based on the degradation rate, we studied the influences of the heterogeneous Fenton method on the coalbed methane output water treatment process parameters, including initial pH, H2O2 concentration, and the catalyst concentration. We also investigated the impacts of overall reaction kinetics of heterogeneous catalytic oxidation on coalbed methane-produced water containing fracturing fluid. Results showed that Fe-Co/γ-Al2O3 as a Fenton catalyst has a good catalytic oxidation effect and can effectively process coalbed methane-produced water. This reaction also followed first-order kinetics. The optimal conditions were as follows: the initial pH of 3.5, a H2O2 concentration of 40 mol L−1, a catalyst concentration of 4 g/L, and an apparent reaction rate constant of 0.0172 min−1. Our results provided a basis to establish methods for treating coalbed methane-produced water.

  14. Ceramic media amended with metal oxide for the capture of viruses in drinking water.

    Science.gov (United States)

    Brown, J; Sobsey, M D

    2009-04-01

    Ceramic materials that can adsorb and/or inactivate viruses in water may find widespread application in low-tech drinking-water treatment technologies in developing countries, where porous ceramic filters and ceramic granular media filters are increasingly promoted for that purpose. We examined the adsorption and subsequent inactivation of bacteriophages MS2 and (phiX-174 on five ceramic media in batch adsorption studies to determine media suitability for use in a ceramic water filter application. The media examined were a kaolinitic ceramic medium and four kaolinitic ceramic media amended with iron or aluminium oxides that had been incorporated into the kaolinitic clays before firing. Batch adsorption tests indicate increased sorption and inactivation of surrogate viruses by media amended with Fe and Al oxide, with FeOOH-amended ceramic inactivating all bacteriophages up to 8 log10. Unmodified ceramic was a poor adsorbent of bacteriophages at less than 1 log10 adsorption-inactivation and high recovery of sorbed phages. These studies suggest that contact with ceramic media, modified with electropositive Fe or Al oxides, can reduce bacteriophages in waters to a greater extent than unmodified ceramic.

  15. Integration of biofiltration and advanced oxidation processes for tertiary treatment of an oil refinery wastewater aiming at water reuse.

    Science.gov (United States)

    Nogueira, A A; Bassin, J P; Cerqueira, A C; Dezotti, M

    2016-05-01

    The combination of biological and chemical oxidation processes is an interesting approach to remove ready, poor, and non-biodegradable compounds from complex industrial wastewaters. In this study, biofiltration followed by H2O2/UV oxidation (or microfiltration) and final reverse osmosis (RO) step was employed for tertiary treatment of an oil refinery wastewater. Biofiltration alone allowed obtaining total organic carbon (TOC), chemical oxygen demand (COD), UV absorbance at 254 nm (UV254), ammonium, and turbidity removal of around 46, 46, 23, 50, and 61 %, respectively. After the combined biological-chemical oxidation treatment, TOC and UV254 removal amounted to 88 and 79 %, respectively. Whereas, the treatment performance achieved with different UV lamp powers (55 and 95 W) and therefore distinct irradiance levels (26.8 and 46.3 mW/cm(2), respectively) were very similar and TOC and UV254 removal rates were highly affected by the applied C/H2O2 ratio. Silt density index (SDI) was effectively reduced by H2O2/UV oxidation, favoring further RO application. C/H2O2 ratio of 1:4, 55 W UV lamp, and 20-min oxidation reaction corresponded to the experimental condition which provided the best cost/benefit ratio for TOC, UV254, and SDI reduction from the biofilter effluent. The array of treatment processes proposed in this study has shown to be adequate for tertiary treatment of the oil refinery wastewater, ensuring the mitigation of membrane fouling problems and producing a final effluent which is suitable for reuse applications.

  16. Evaluation of biological hydrogen sulfide oxidation coupled with two-stage upflow filtration for groundwater treatment.

    Science.gov (United States)

    Levine, Audrey D; Raymer, Blake J; Jahn, Johna

    2004-01-01

    Hydrogen sulfide in groundwater can be oxidized by aerobic bacteria to form elemental sulfur and biomass. While this treatment approach is effective for conversion of hydrogen sulfide, it is important to have adequate control of the biomass exiting the biological treatment system to prevent release of elemental sulfur into the distribution system. Pilot scale tests were conducted on a Florida groundwater to evaluate the use of two-stage upflow filtration downstream of biological sulfur oxidation. The combined biological and filtration process was capable of excellent removal of hydrogen sulfide and associated turbidity. Additional benefits of this treatment approach include elimination of odor generation, reduction of chlorine demand, and improved stability of the finished water.

  17. Sequencing treatment of industrial wastewater with ultraviolet/H2O2 advanced oxidation and moving bed bioreactor

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Mehrabani Ardekani

    2015-01-01

    Full Text Available Aims: The main purpose of this study was to determine the efficiency of a sequencing treatment including ultraviolet (UV/H 2 O 2 oxidation followed by a moving bed bioreactor (MBBR. Materials and Methods: Effect of solution pH, reaction time, and H 2 O 2 concentration were investigated for an industrial wastewater sample. The effluent of the advanced oxidation processes unit was introduced to the MBBR operated for three hydraulic retention times of 4, 8, and 12 h. Results: The optimum condition for industrial wastewater treatment via advanced oxidation was solution pH: 7, H 2 O 2 dose: 1000 mg/L and 90 min reaction time. These conditions led to 74.68% chemical oxygen demand (COD removal and 66.15% biochemical oxygen demand (BOD 5 removal from presedimentation step effluent that initially had COD and BOD 5 contents of 4,400 and 1,950 mg/L, respectively. Conclusion: Combination of UV/H 2 O 2 advanced oxidation with MBBR could result in effluents that meet water quality standards for discharge to receiving waters.

  18. Investigation of anodic oxide coatings on zirconium after heat treatment

    International Nuclear Information System (INIS)

    Sowa, Maciej; Dercz, Grzegorz; Suchanek, Katarzyna; Simka, Wojciech

    2015-01-01

    Highlights: • Oxide layers prepared via PEO of zirconium were subjected to heat treatment. • Surface characteristics were determined for the obtained oxide coatings. • Heat treatment led to the partial destruction of the anodic oxide layer. • Pitting corrosion resistance of zirconium was improved after the modification. - Abstract: Herein, results of heat treatment of zirconium anodised under plasma electrolytic oxidation (PEO) conditions at 500–800 °C are presented. The obtained oxide films were investigated by means of SEM, XRD and Raman spectroscopy. The corrosion resistance of the zirconium specimens was evaluated in Ringer's solution. A bilayer oxide coatings generated in the course of PEO of zirconium were not observed after the heat treatment. The resulting oxide layers contained a new sublayer located at the metal/oxide interface is suggested to originate from the thermal oxidation of zirconium. The corrosion resistance of the anodised metal was improved after the heat treatment

  19. Direct versus indirect electrochemical oxidation of pesticide polluted drainage water containing sodium chloride

    DEFF Research Database (Denmark)

    Muff, Jens; Erichsen, Rasmus; Damgaard, Christian

    2008-01-01

    Drainage water from a depot of chemical waste, polluted with a mixture of organophosphates and degradation products was treated by a direct as well as an indirect electrochemical method using a Ti/Pt-Ir anode and Stainless Steel 304 cathode. With a concentration of 0.7%, sodium chloride...... the treatment. Indirect electrochemical treatment, where a highly oxidized brine solution was added to the drainage water, revealed immediately reduction in COD, and similar to the direct treatment, degradation of all of the pesticide pollutants was obtained except for the O,O,O-triethyl-phosphoric acid...... concentrations. Analyses of the actual pollutants, Me-Parathion, parathion, malathion and degradation products, confirmed that the concentrations of all initial pollutants were eliminated during the treatment. The only exception was O,O,O-triethyl-phosphoric acid, a degradation product which was formed during...

  20. Direct versus indirect electrochemical oxidation of pesticide polluted drainage water containing sodium chloride

    DEFF Research Database (Denmark)

    Muff, Jens; Erichsen, Rasmus; Damgaard, Christian

    2008-01-01

    the treatment. Indirect electrochemical treatment, where a highly oxidized brine solution was added to the drainage water, revealed immediately reduction in COD, and similar to the direct treatment, degradation of all of the pesticide pollutants was obtained except for the O,O,O-triethyl-phosphoric acid......Drainage water from a depot of chemical waste, polluted with a mixture of organophosphates and degradation products was treated by a direct as well as an indirect electrochemical method using a Ti/Pt-Ir anode and Stainless Steel 304 cathode. With a concentration of 0.7%, sodium chloride...... concentrations. Analyses of the actual pollutants, Me-Parathion, parathion, malathion and degradation products, confirmed that the concentrations of all initial pollutants were eliminated during the treatment. The only exception was O,O,O-triethyl-phosphoric acid, a degradation product which was formed during...

  1. Kinetics and mechanism of methane oxidation in supercritical water

    International Nuclear Information System (INIS)

    Rofer, C.K.; Streit, G.E.

    1988-10-01

    This project, is a Hazardous Waste Remedial Actions Program (HAZWRAP) Research and Development task being carried out by the Los Alamos National Laboratory. Its objective is to achieve an understanding of the technology for use in scaling up and applying oxidation in supercritical water as a viable process for treating a variety of Department of Energy Defense Programs (DOE-DP) waste streams. This report presents experimental results for the kinetics of the oxidation of methane and methanol in supercritical water and computer modeling results for the oxidation of carbonmonoxide and methane in supercritical water. The experimental and modeling results obtained to date on these one-carbon model compounds indicate that the mechanism of oxidation in supercritical water can be represented by free-radical reactions with appropriate modifications for high pressure and the high water concentration. If these current trends are sustained, a large body of existing literature data on the kinetics of elementary reactions can be utilized to predict the behavior of other compounds and their mixtures. 7 refs., 4 figs., 3 tabs

  2. State of the art of produced water treatment.

    Science.gov (United States)

    Jiménez, S; Micó, M M; Arnaldos, M; Medina, F; Contreras, S

    2018-02-01

    Produced water (PW) is the wastewater generated when water from underground reservoirs is brought to the surface during oil or gas extraction. PW is generated in large amounts and has a complex composition, containing various toxic organic and inorganic compounds. PW is currently treated in conventional trains that include phase separators, decanters, cyclones and coarse filters in order to comply with existing regulation for discharge. These treatment trains do not achieve more restrictive limitations related to the reuse of the effluent (reinjection into extraction wells) or other beneficial uses (e.g., irrigation). Therefore, and to prevent environmental pollution, further polishing processes need to be carried out. Characterization of the PW to determine major constituents is the first step to select the optimum treatment for PW, coupled with environmental factors, economic considerations, and local regulatory framework. This review tries to provide an overview of different treatments that are being applied to polish this type of effluents. These technologies include membranes, physical, biological, thermal or chemical treatments, where special emphasis has been made on advanced oxidation processes due to the advantages offered by these processes. Commercial treatments, based on the combination, modification and improvement of simpler treatments, were also discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. ENGINEERING BULLETIN: SUPERCRITICAL WATER OXIDATION

    Science.gov (United States)

    This engineering bulletin presents a description and status of supercritical water oxidation technology, a summary of recent performance tests, and the current applicability of this emerging technology. This information is provided to assist remedial project managers, contractors...

  4. Flow analysis in a supercritical water oxidation reactor

    International Nuclear Information System (INIS)

    Oh, C.H.; Kochan, R.J.; Beller, J.M.

    1996-01-01

    Supercritical water oxidation (SCWO), also known as hydrothermal oxidation (HTO), involves the oxidation of hazardous waste at conditions of elevated temperature and pressure (e.g., 500 C--600 C and 234.4 bar) in the presence of approximately 90% of water and a 10% to 20% excess amount of oxidant over the stoichiometric requirement. Under these conditions, organic compounds are completely miscible with supercritical water, oxygen and nitrogen, and are rapidly oxidized to carbon dioxide and water. The essential part of the process is the reactor. Many reactor designs such as tubular, vertical vessel, and transpiring wall type have been proposed, patented, and tested at both bench and pilot scales. These designs and performances need to be scaled up to a waste throughput 10--100 times that currently being tested. Scaling of this magnitude will be done by creating a numerical thermal-hydraulic model of the smaller reactor for which test data is available, validating the model against the available data, and then using the validated model to investigate the larger reactor performance. This paper presents a flow analysis of the MODAR bench scale reactor (vertical vessel type). These results will help in the design of the reactor in an efficient manner because the flow mixing coupled with chemical kinetics eventually affects the process destruction efficiency

  5. Oxidation of coals in the course of mechanical treatment

    Energy Technology Data Exchange (ETDEWEB)

    A.G. Proidakov; G.A. Kalabin [Irkutsk State University, Irkutsk (Russian Federation)

    2009-04-15

    The results of a study of coal oxidation under stationary conditions and during mechanical treatment are presented. A considerable increase in the reaction rate constants of coal oxidation during mechanical treatment because of oxidative mechanical degradation was found.

  6. Stabilization of arsenic and chromium polluted soils using water treatment residues

    DEFF Research Database (Denmark)

    Nielsen, Sanne Skov

    water and can be used as a soil amendment to decrease the mobility of CCA in contaminated soil. Stabilization with Fe-WTR was tested at the Collstrop site in Hillerød, Denmark. The site has been polluted with a wide range of wood impregnation agents including CCA during 40 years of wood impregnating...... of contaminants. Arsenic, chromium and copper cannot be degraded and existing methods for cleaning the soil are rarely used as they are expensive and technically demanding. Chemical stabilization of polluted soil is an alternative method for soil remediation, especially metal contamination, and consists in adding...... or other sorbents. Iron water treatment residues mainly consist of ferrihydrite, an oxidized iron oxy-hydroxide with a high reactivity and a large specific surface area with a high capacity for adsorption. Iron water treatment residues (Fe-WTR) are a by-product from treatment of groundwater to drinking...

  7. Photocatalytic Oxidation and Reduction Chemistry and a New Process for Treatment of Pink Water and Related Contaminated Water

    Science.gov (United States)

    1996-10-01

    Influence of pH on the Degradation Kinetics of Nitrophenol Isomers in a Heterogeneous ...34 Heterogeneous Photocatalytic Degradation of Organic Water Contaminants: Kinetics and Hydroxyl Radical Mechanisms," Ph.D. Thesis, Raleigh, NC: North Carolina...Dioxide Systems : Photocatalytic Degradation of Chloro- and Nitrophenols ." Trace Met. Environ 3, no. Photocatalytic Purification and Treatment of Water

  8. Potential applications of plasma science techniques for water treatment systems

    International Nuclear Information System (INIS)

    Pavlik, D.

    1994-01-01

    The historical evolution of water treatment techniques and their impact on man and his environment are presented. Ancient man recognized the relationship between good water and good health. However, it was not until the late 1800's that man's own contribution to the pollution of water via biological and chemical contamination of the water stream was recognized as having adverse affects on water quality. Since that time virtually every nation has adopted laws and regulations to ensure that safe sources of unpolluted water are available to its citizens. In the United States, water quality is governed by the Clean Water Act of 1972 administered at the federal level by the Environmental Protection Agency (EPA). Further, each state has established its equivalent agency which administers its own laws and regulations. Different biological and chemical biohazards present in the water system are discussed. Biological contaminants include various types of viruses, bacteria, fungii, molds, yeasts, algae, amoebas, and parasites. Chemical contaminates include elemental heavy metals and other organic and inorganic compounds which interfere with normal biological functions. Conventional water treatments for both consumption and sewage effluent commonly employ four different principals: mechanical filtration, quiescent gravity settling, biological oxidation, and chemical treatment. Although these techniques have greatly reduced the incidence of water-borne disease recent studies suggest that more effective means of eliminating biohazards are needed. Regulatory requirements for more aggressive treatment and elimination of residual contaminants present a significant opportunity for the application of various forms of electromagnetic radiation techniques. A comparison between conventional techniques and more advanced methods using various forms of electromagnetic radiation is discussed

  9. Oxide/water interfaces: how the surface chemistry modifies interfacial water properties

    International Nuclear Information System (INIS)

    Gaigeot, Marie-Pierre; Sprik, Michiel; Sulpizi, Marialore

    2012-01-01

    The organization of water at the interface with silica and alumina oxides is analysed using density functional theory-based molecular dynamics simulation (DFT-MD). The interfacial hydrogen bonding is investigated in detail and related to the chemistry of the oxide surfaces by computing the surface charge density and acidity. We find that water molecules hydrogen-bonded to the surface have different orientations depending on the strength of the hydrogen bonds and use this observation to explain the features in the surface vibrational spectra measured by sum frequency generation spectroscopy. In particular, ‘ice-like’ and ‘liquid-like’ features in these spectra are interpreted as the result of hydrogen bonds of different strengths between surface silanols/aluminols and water. (paper)

  10. Process options for treatment of organic containing ILWs by wet oxidation

    International Nuclear Information System (INIS)

    Holman, D.J.

    1989-01-01

    The process chemistry, applications and experience with several wet oxidation options are reviewed along with criteria for the selection of viable systems and plant designs, covering a range of organic wastes, including solvents, cellulosic filters, chelant decontamination reagents and ion exchange resins. The use of hydrogen peroxide to treat water-cooled reactor residues containing mixed inorganic and organic filter materials with ion exchange resins is examined in further detail along with treatment of secondary arisings. The technical and financial justifications for treatment are examined along with the engineering requirements to retro-fit the required plant to an existing cement encapsulation facility. (author)

  11. Mine water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Komissarov, S V

    1980-10-01

    This article discusses composition of chemical compounds dissolved or suspended in mine waters in various coal basins of the USSR: Moscow basin, Kuzbass, Pechora, Kizelovsk, Karaganda, Donetsk and Chelyabinsk basins. Percentage of suspended materials in water depending on water source (water from water drainage system of dust suppression system) is evaluated. Pollution of mine waters with oils and coli bacteria is also described. Recommendations on construction, capacity of water settling tanks, and methods of mine water treatment are presented. In mines where coal seams 2 m or thicker are mined a system of two settling tanks should be used: in the upper one large grains are settled, in the lower one finer grains. The upper tank should be large enough to store mine water discharged during one month, and the lower one to store water discharged over two months. Salty waters from coal mines mining thin coal seams should be treated in a system of water reservoirs from which water evaporates (if climatic conditions permit). Mine waters from mines with thin coal seams but without high salt content can be treated in a system of long channels with water plants, which increase amount of oxygen in treated water. System of biological treatment of waste waters from mine wash-houses and baths is also described. Influence of temperature, sunshine and season of the year on efficiency of mine water treatment is also assessed. (In Russian)

  12. Preparation of hydrogenated-TiO2/Ti double layered thin films by water vapor plasma treatment

    International Nuclear Information System (INIS)

    Pranevicius, L.L.; Milcius, D.; Tuckute, S.; Gedvilas, K.

    2012-01-01

    Highlights: ► We investigated reaction of water plasma with nanocrystalline TiO 2 films. ► Simultaneous oxidation and hydrogenation of Ti was observed during plasma treatment. ► Water plasma treatment forms hydrogenated nanocrystalline TiO 2 in the shallow surface. - Abstract: We have investigated the structural and compositional variations in 200–500 nm thick Ti films deposited by magnetron sputter-deposition technique and treated in water vapor plasma at different processing powers. It was found that the upper layer of treated film with the thickness of 110 nm was changed into the black hydrogenated-TiO 2 with around 16 nm sized nanocystals during 10 min for dissipated power 200 W at room temperature. Analysis of the experimental results is used to obtain insights into the effects of water layer adsorbed on hydrophilic oxidized titanium surfaces exposed to plasma radiation.

  13. Development of an Integrated Wastewater Treatment System/water reuse/agriculture model

    Science.gov (United States)

    Fox, C. H.; Schuler, A.

    2017-12-01

    Factors like increasing population, urbanization, and climate change have made the management of water resources a challenge for municipalities. By understanding wastewater recycling for agriculture in arid regions, we can expand the supply of water to agriculture and reduce energy use at wastewater treatment plants (WWTPs). This can improve management decisions between WWTPs and water managers. The objective of this research is to develop a prototype integrated model of the wastewater treatment system and nearby agricultural areas linked by water and nutrients, using the Albuquerque Southeast Eastern Reclamation Facility (SWRF) and downstream agricultural system as a case study. Little work has been done to understand how such treatment technology decisions affect the potential for water ruse, nutrient recovery in agriculture, overall energy consumption and agriculture production and water quality. A holistic approach to understanding synergies and tradeoffs between treatment, reuse, and agriculture is needed. For example, critical wastewater treatment process decisions include options to nitrify (oxidize ammonia), which requires large amounts of energy, to operate at low dissolved oxygen concentrations, which requires much less energy, whether to recover nitrogen and phosphorus, chemically in biosolids, or in reuse water for agriculture, whether to generate energy from anaerobic digestion, and whether to develop infrastructure for agricultural reuse. The research first includes quantifying existing and feasible agricultural sites suitable for irrigation by reuse wastewater as well as existing infrastructure such as irrigation canals and piping by using GIS databases. Second, a nutrient and water requirement for common New Mexico crop is being determined. Third, a wastewater treatment model will be utilized to quantify energy usage and nutrient removal under various scenarios. Different agricultural reuse sensors and treatment technologies will be explored. The

  14. Microbial oxidation of soluble sulfide in produced water from the Bakkeen Sands

    Energy Technology Data Exchange (ETDEWEB)

    Gevertz, D.; Zimmerman, S. [Agouron Institute, La Jolla, CA (United States); Jenneman, G.E. [Phillips Petroleum Company, Bartlesville, OK (United States)] [and others

    1995-12-31

    The presence of soluble sulfide in produced water results in problems for the petroleum industry due to its toxicity, odor, corrosive nature, and potential for wellbore plugging. Sulfide oxidation by indigenous nitrate-reducing bacteria (NRB) present in brine collected from wells at the Coleville Unit (CVU) in Saskatchewan, Canada, was investigated. Sulfide oxidation took place readily when nitrate and phosphate were added to brine enrichment cultures, resulting in a decrease in sulfide levels of 99-165 ppm to nondetectable levels (< 3.3 ppm). Produced water collected from a number of producing wells was screened to determine the time required for complete sulfide oxidation, in order to select candidate wells for treatment. Three wells were chosen, based on sulfide removal in 48 hours or less. These wells were treated down the backside of the annulus with a solution containing 10 mM KNO{sub 3} and 100 {mu}M NaH{sub 2}PO{sub 4}. Following a 24- to 72-hour shut-in, reductions in pretreatment sulfide levels of greater than 90% were observed for two of the wells, as well as sustained sulfide reductions of 50% for at least two days following startup. NRB populations in the produced brine were observed to increase significantly following treatment, but no significant increases in sulfate-reducing bacteria were observed. These results demonstrate the technical feasibility of stimulating indigenous populations of NRB to remediate and control sulfide in produced brine.

  15. The economic pre-treatment of coal mine drainage water with caustic and ozone.

    Science.gov (United States)

    Boyden, B H; Nador, L; Addleman, S; Jeston, L

    2017-09-01

    Coal mine drainage waters are low in pH with varying amounts of iron and manganese and are generally brackish. The Austar Coal Mine in NSW, Australia, sought alternatives to their current lime dosing as the pre-treatment before the downstream reverse osmosis plant. Undesirable operating aspects of the current system include manganese and gypsum scaling/fouling, the need for anti-scalants and reduced water recovery. Thirteen processes for acid mine drainage were initially considered. The preferred process of caustic and ozone for Mn(II) oxidation was pilot tested at up to 0.74 kL/hr at the mine site. Under proper conditions and no aeration, about 81 per cent of the Fe could be removed (initially at 156 mg/L) as green rust. Supplemental aeration followed first-order kinetics and allowed 99.9 per cent Fe(II) oxidation and removal but only with a hydraulic residence time of about 47 minutes. The addition of supplemental Cu catalyst improved Fe removal. Ozone applied after caustic was effective in stoichiometrically oxidising recalcitrant Mn(II) and any remaining Fe(II). Control of the ozonation was achieved using the oxidation reduction potential during oxidation of the Mn(II) species. The use of caustic, followed by ozone, proved economically comparable to the current lime pre-treatment.

  16. Oxidation behavior of austenitic iron-base ODS alloy in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Behnamian, Y.; Dong, Z.; Zahiri, R.; Kohandehghan, A.; Mitlin, D., E-mail: behnamia@ualberta.ca, E-mail: zdong@ualberta.ca, E-mail: kohandeh@ualberta.ca, E-mail: rzahiris@ualberta.ca, E-mail: dave.mitlin@ualberta.ca [Univ. of Alberta, Edmondon, AB (Canada); Zhou, Z., E-mail: zhouzhj@mater.ustb.edu.cn [Univ. of Science and Tech. Beijing, Beijing (China); Chen, W.; Luo, J., E-mail: weixing.chen@ualberta.ca, E-mail: Jingli.luo@ualberta.ca [Univ. of Alberta, Edmonton, AB (Canada); Zheng, W., E-mail: wenyue@nrcan.gc.ca [Natural Resources Canada, Canmet MATERIALS, Hamilton, ON (Canada); Guzonas, D. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

    2014-07-01

    In this study, the effect of exposure time on the corrosion of the 304 stainless steel based oxide dispersion strengthened alloy, SS304ODS, in supercritical water was investigated at 650 {sup o}C with constant dissolved oxygen concentration. The results show that the oxidation of SS304ODS in supercritical water followed a parabolic law at 650 {sup o}C. Discontinuous oxide scale with two distinct layers has formed after 550 hours. The inner layer was chromium-rich while the outer layer was iron-rich (Magnetite). The oxide islands grow with increasing the exposure time. With increasing exposure time, the quantity of oxide islands increased in which major preferential growth along oxide-substrate interface was observed. The possible mechanism of SS304ODS oxidation in supercritical water was also discussed. (author)

  17. Ozonated water in the post-harvest treatment of coffee fruits

    Directory of Open Access Journals (Sweden)

    Fernando J. B. Brandão

    Full Text Available ABSTRACT Ozone is used in many countries for the treatment of effluents, becoming a viable alternative in sanitation of coffee wastewater. However, the strong ozone oxidation, responsible for its germicidal effect, can also compromise grain and beverage quality. The objective of this study was to evaluate the quality of Arabica coffee in different periods of treatment with ozonated water and its effect after drying. Coffee fruits were subjected to ozonation at regular intervals of 0, 5, 10, 20, and 30 min, with continuous stirring promoted by a recirculating water system at constant rate of 1 ppm of solubilized ozone. The design was completely randomized with five treatments and four replicates. After obtaining the data, the analysis of variance was performed and means were compared by Tukey test (p ≤ 0.05. The results showed a partial reduction of fungi after washing with ozonated water, but the same effect was not observed after drying. For coffee quality analysis, the longest times of exposure to the solubilized gas in the water produced some negative results in electrical conductivity and total and reducing sugars. However, the sensory quality of the beverage was maintained.

  18. Hydrogen incorporation by plasma treatment gives mesoporous black TiO 2 thin films with visible photoelectrochemical water oxidation activity

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Syed Z.; Reed, Allen; Nagpure, Suraj; Wanninayake, Namal; Browning, James F.; Strzalka, Joseph; Kim, Doo Young; Rankin, Stephen E.

    2018-05-01

    In this work, we use neutron reflectometry (NR) to investigate the roles of hydrogen in plasma treated hydrogen doped mesoporous black titania thin films in their visible light absorption and enhanced photoactivity for water oxidation. The cubic ordered mesoporous TiO2 thin films are prepared by a surfactant-templated sol-gel method and are treated with hydrogen plasma, an approach hypothesized to capitalize on the high degree of disorder in the material and the high energy of the plasma species to achieve efficient hydrogen doping. UV-vis absorbance spectra indicate that H2 plasma treatment makes TiO2 films black, with broad-spectrum enhancement of visible light absorption, and XPS analysis shows peak for Ti3+ state in treated films. The presence of hydrogen in black mesoporous titania (H-TiO2) films is confirmed by the scattering length density (SLD) profiles obtained from neutron reflectometry measurements. The H-TiO2 shows ca. 28 times and 8 times higher photocurrent for photoelectrochemical water oxidation compared to undoped TiO2 films under UV (365 nm) and blue (455 nm) LED irradiation, respectively. These findings provide the first direct evidence that the dramatic change in visible light absorbance of H-treated black TiO2 is accompanied by significant hydrogen uptake and not just Ti3+ generation or surface disordering.

  19. Using advanced oxidation treatment for biofilm inactivation by varying water vapor content in air plasma

    Science.gov (United States)

    Ryota, Suganuma; Koichi, Yasuoka

    2015-09-01

    Biofilms are caused by environmental degradation in food factories and medical facilities. The inactivation of biofilms involves making them react with chemicals including chlorine, hydrogen peroxide, and ozone, although inactivation using chemicals has a potential problem because of the hazardous properties of the residual substance and hydrogen peroxide, which have slow reaction velocity. We successfully performed an advanced oxidation process (AOP) using air plasma. Hydrogen peroxide and ozone, which were used for the formation of OH radicals in our experiment, were generated by varying the amount of water vapor supplied to the plasma. By varying the content of the water included in the air, the main product was changed from air plasma. When we increased the water content in the air, hydrogen peroxide was produced, while ozone peroxide was produced when we decreased the water content in the air. By varying the amount of water vapor, we realized a 99.9% reduction in the amount of bacteria in the biofilm when we discharged humidified air only. This work was supported by JSPS KAKENHI Grant Number 25630104.

  20. Microbial degradation of pesticides in rapid sand filters used for drinking water treatment

    DEFF Research Database (Denmark)

    Hedegaard, Mathilde Jørgensen

    significantly with the maximum methane concentration in the raw water and did not correlate with other water quality parameters, such as the ammonium concentration. Furthermore, the connection between bentazone degradation and methane oxidation in filter sand was demonstrated by inhibition experiments, in which...... sustainable methods to remove pesticides from polluted water sources. Aeration of anaerobic groundwater, followed by biological rapid sand filtration is a widespread technology in drinking water treatment. Even though these systems are not designed for removal of trace contaminants, they have shown potential...... for microbial degradation of pesticides and their degradation products. If pesticides can be removed in rapid sand filters, it is of large commercial interest due to the importance in maintaining a simple, sustainable water treatment. To take advantage of the microbial pesticide degradation and identify...

  1. Treatments of acid waters; Tratamientos pasivos de aguas acidas

    Energy Technology Data Exchange (ETDEWEB)

    Delgado Fernandez, J. L.

    2000-07-01

    The exploitation of coal mining locations causes acid effluents due to the oxidation of the sulfurous minerals content of the rocks, denominated acid waters. There are Pyritic materials, pyres and sulphates associated to acid waters that in presence of water, oxygen and certain bacteria (mainly Thiobacillus ferro oxidants), are oxidized, by means of a chemistry reaction, yielding different products. (Author)

  2. Environmental Parameters Affecting the Algal Diversity in a Sewage Water Treatment Plant

    International Nuclear Information System (INIS)

    Hammad, D.M.; Tawfik, T.A.; Ismail, G.A.; Abou El-Khair, W.S.; Abou El-Nour, F.

    2008-01-01

    The present investigation was carried out at a tertiary sewage water treatment plant located at El-Kattameya city, Cairo, Egypt, for a duration period of 12 months during 2004. The present work aimed to study the algal diversity (phyto benthos and phytoplankton) of the different tanks (collector, oxidation, settling and effluent) included in the tertiary sewage treatment system with respect to changes in physico-chemical characteristics of sewage water during the different seasons to be used for golf course irrigation. The treatment system is of the physico-biological type. Representing data of the physico-chemical parameters are air and water temperatures, ph, electrical conductivity (EC), dissolved oxygen (DO), chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended salts (TSS), total alkalinity, nutrients (nitrate, ammonia, phosphate, ortho-phosphorus, phosphorus and silicate), as well as major ions (calcium, potassium, sodium, magnesium, sulfate and chloride). In addition, the treatment efficiency of the system was evaluated and the suitability of using the effluent in irrigation purposes was discussed

  3. p-Type Transparent Conducting Oxide/n-Type Semiconductor Heterojunctions for Efficient and Stable Solar Water Oxidation.

    Science.gov (United States)

    Chen, Le; Yang, Jinhui; Klaus, Shannon; Lee, Lyman J; Woods-Robinson, Rachel; Ma, Jie; Lum, Yanwei; Cooper, Jason K; Toma, Francesca M; Wang, Lin-Wang; Sharp, Ian D; Bell, Alexis T; Ager, Joel W

    2015-08-05

    Achieving stable operation of photoanodes used as components of solar water splitting devices is critical to realizing the promise of this renewable energy technology. It is shown that p-type transparent conducting oxides (p-TCOs) can function both as a selective hole contact and corrosion protection layer for photoanodes used in light-driven water oxidation. Using NiCo2O4 as the p-TCO and n-type Si as a prototypical light absorber, a rectifying heterojunction capable of light driven water oxidation was created. By placing the charge separating junction in the Si using a np(+) structure and by incorporating a highly active heterogeneous Ni-Fe oxygen evolution catalyst, efficient light-driven water oxidation can be achieved. In this structure, oxygen evolution under AM1.5G illumination occurs at 0.95 V vs RHE, and the current density at the reversible potential for water oxidation (1.23 V vs RHE) is >25 mA cm(-2). Stable operation was confirmed by observing a constant current density over 72 h and by sensitive measurements of corrosion products in the electrolyte. In situ Raman spectroscopy was employed to investigate structural transformation of NiCo2O4 during electrochemical oxidation. The interface between the light absorber and p-TCO is crucial to produce selective hole conduction to the surface under illumination. For example, annealing to produce more crystalline NiCo2O4 produces only small changes in its hole conductivity, while a thicker SiOx layer is formed at the n-Si/p-NiCo2O4 interface, greatly reducing the PEC performance. The generality of the p-TCO protection approach is demonstrated by multihour, stable, water oxidation with n-InP/p-NiCo2O4 heterojunction photoanodes.

  4. Comparison in decoloration efficiency among radiation, ultraviolet ray and Fenton oxidation treatment for aqueous solution of dyes

    International Nuclear Information System (INIS)

    Shimokawa, Toshishige; Sawai, Takeshi

    1984-01-01

    To establish the methods of oxidation and decomposition treatment for dyeing waste water, the processes by radiation, ultraviolet ray and Fenton oxidation were examined comparatively for the decoloration efficiency. The dyes tested were commercially available reactive dyes, RBO-3R, DBR-BB, MBY-6GS and RBB-R. In the radiation process, the dye solution was irradiated with gamma ray of cobalt-60 while blowing air through it. Radiation process and Fenton oxidation were excellent for decoloration. Ultraviolet ray was low in the treatment efficiency, so it is not practical. In the radiation process, the addition of a reagent and the adjustment of pH are not required unlike the case of the Fenton oxidation process. Its continuous operation is also possible, so it is a highly practical means. (Mori, K.)

  5. Nitric oxide reduces oxidative damage induced by water stress in sunflower plants

    Directory of Open Access Journals (Sweden)

    Inês Cechin

    2015-06-01

    Full Text Available Drought is one of the main environmental constraints that can reduce plant yield. Nitric oxide (NO is a signal molecule involved in plant responses to several environmental stresses. The objective of this study was to investigate the cytoprotective effect of a single foliar application of 0, 1, 10 or 100 µM of the NO donor sodium nitroprusside (SNP in sunflower plants under water stress. Water stressed plants treated with 1μM SNP showed an increase in the relative water content compared with 0 μM SNP. Drought reduced the shoot dry weight but SNP applications did not result in alleviation of drought effects. Neither drought nor water stress plus SNP applications altered the content of photosynthetic pigments. Stomatal conductance was reduced by drought and this reduction was accompanied by a significant reduction in intercellular CO2 concentration and photosynthesis. Treatment with SNP did not reverse the effect of drought on the gas exchange characteristics. Drought increased the level of malondialdehyde (MDA and proline and reduced pirogalol peroxidase (PG-POD activity, but did not affect the activity of superoxide dismutase (SOD. When the water stressed plants were treated with 10 μM SNP, the activity of PG-POD and the content of proline were increased and the level of MDA was decreased. The results show that the adverse effects of water stress on sunflower plants are dependent on the external NO concentration. The action of NO may be explained by its ability to increase the levels of antioxidant compounds and the activity of ROS-scavenging enzymes.

  6. Urban net-zero water treatment and mineralization: experiments, modeling and design.

    Science.gov (United States)

    Englehardt, James D; Wu, Tingting; Tchobanoglous, George

    2013-09-01

    Water and wastewater treatment and conveyance account for approximately 4% of US electric consumption, with 80% used for conveyance. Net zero water (NZW) buildings would alleviate demands for a portion of this energy, for water, and for the treatment of drinking water for pesticides and toxic chemical releases in source water. However, domestic wastewater contains nitrogen loads much greater than urban/suburban ecosystems can typically absorb. The purpose of this work was to identify a first design of a denitrifying urban NZW treatment process, operating at ambient temperature and pressure and circum-neutral pH, and providing mineralization of pharmaceuticals (not easily regulated in terms of environmental half-life), based on laboratory tests and mass balance and kinetic modeling. The proposed treatment process is comprised of membrane bioreactor, iron-mediated aeration (IMA, reported previously), vacuum ultrafiltration, and peroxone advanced oxidation, with minor rainwater make-up and H2O2 disinfection residual. Similar to biological systems, minerals accumulate subject to precipitative removal by IMA, salt-free treatment, and minor dilution. Based on laboratory and modeling results, the system can produce potable water with moderate mineral content from commingled domestic wastewater and 10-20% rainwater make-up, under ambient conditions at individual buildings, while denitrifying and reducing chemical oxygen demand to below detection (<3 mg/L). While economics appear competitive, further development and study of steady-state concentrations and sludge management options are needed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Superconductor made by electrolyzed and oxidized water

    OpenAIRE

    Liu, Chia-Jyi; Wu, Tsung-Hsien; Hsu, Lin-Li; Wang, Jung-Sheng; Chen, Shu-Yo; Chang, Wei Jen; Lin, Jiunn-Yuan

    2006-01-01

    By deintercalation of Na+ followed by inserting bilayers of water molecules into the host lattice, the layered cobalt oxide of gamma-Na0.7CoO2 undergoes a topotactic transformation to a layered cobalt oxyhydrate of Na0.35(H2O)1.3CoO2-delta with the c-axis expanded from c = 10.9 anstrom to c = 19.6 anstrom. In this paper, we demonstrate that the superconducting phase of c = 19.6 anstrom can be directly obtained by simply immersing gamma-Na0.7CoO2 powders in electrolyzed/oxidized (EO) water, wh...

  8. Water clustering on nanostructured iron oxide films

    DEFF Research Database (Denmark)

    Merte, Lindsay Richard; Bechstein, Ralf; Peng, G.

    2014-01-01

    , but it is not well-understood how these hydroxyl groups and their distribution on a surface affect the molecular-scale structure at the interface. Here we report a study of water clustering on a moire-structured iron oxide thin film with a controlled density of hydroxyl groups. While large amorphous monolayer...... islands form on the bare film, the hydroxylated iron oxide film acts as a hydrophilic nanotemplate, causing the formation of a regular array of ice-like hexameric nanoclusters. The formation of this ordered phase is localized at the nanometre scale; with increasing water coverage, ordered and amorphous...

  9. Photocatalytic Water Oxidation on ZnO: A Review

    Directory of Open Access Journals (Sweden)

    Sharifah Bee Abdul Hamid

    2017-03-01

    Full Text Available The investigation of the water oxidation mechanism on photocatalytic semiconductor surfaces has gained much attention for its potential to unlock the technological limitations of producing H2 from carbon-free sources, i.e., H2O. This review seeks to highlight the available scientific and fundamental understanding towards the water oxidation mechanism on ZnO surfaces, as well as present a summary on the modification strategies carried out to increase the photocatalytic response of ZnO.

  10. Destruction of energetic materials by supercritical water oxidation

    International Nuclear Information System (INIS)

    Beulow, S.J.; Dyer, R.B.; Harradine, D.M.; Robinson, J.M.; Oldenborg, R.C.; Funk, K.A.; McInroy, R.E.; Sanchez, J.A.; Spontarelli, T.

    1993-01-01

    Supercritical water oxidation is a relatively low-temperature process that can give high destruction efficiencies for a variety of hazardous chemical wastes. Results are presented examining the destruction of high explosives and propellants in supercritical water and the use of low temperature, low pressure hydrolysis as a pretreatment process. Reactions of cyclotrimethylene trinitramine (RDX), cyclotetramethylene tetranitramine (HMX), nitroguanidine (NQ), pentaerythritol tetranitrate (PETN), and 2,4,6-trinitrotoluene (TNT) are examined in a flow reactor operated at temperatures between 400 degrees C and 650 degrees C. Explosives are introduced into the reactor at concentrations below the solubility limits. For each of the compounds, over 99.9% is destroyed in less than 30 seconds at temperatures above 600 degrees C. The reactions produce primarily N 2 , N 2 O,CO 2 , and some nitrate and nitrite ions. The distribution of reaction products depends on reactor pressure, temperature, and oxidizer concentration. Kinetics studies of the reactions of nitrate and nitrite ions with various reducing reagents in supercritical water show that they can be rapidly and completely destroyed at temperatures above 525 degrees C. The use of slurries and hydrolysis to introduce high concentrations of explosives into a supercritical water reactor is examined. For some compounds the rate of reaction depends on particle size. The hydrolysis of explosives at low temperatures (<100 degrees C) and low pressures (<1 atm) under basic conditions produces water soluble, non-explosive products which are easily destroyed by supercritical water oxidation. Large pieces of explosives (13 cm diameter) have been successfully hydrolyzed. The rate, extent, and products of the hydrolysis depend on the type and concentration of base. Results from the base hydrolysis of triple base propellant M31A1E1 and the subsequent supercritical water oxidation of the hydrolysis products are presented

  11. Nonaqueous electrocatalytic water oxidation by a surface-bound Ru(bda)(L)₂ complex.

    Science.gov (United States)

    Sheridan, Matthew V; Sherman, Benjamin D; Wee, Kyung-Ryang; Marquard, Seth L; Gold, Alexander S; Meyer, Thomas J

    2016-04-21

    The rate of electrocatalytic water oxidation by the heterogeneous water oxidation catalyst [Ru(bda)(4-O(CH2)3P(O3H2)2-pyr)2], , (pyr = pyridine; bda = 2,2'-bipyridine-6,6'-dicarboxylate) on metal oxide surfaces is greatly enhanced relative to water as the solvent. In these experiments with propylene carbonate (PC) as the nonaqueous solvent, water is the limiting reagent. Mechanistic studies point to atom proton transfer (APT) as the rate limiting step in water oxidation catalysis.

  12. Recycling of end-of-life reverse osmosis membranes by oxidative treatment: a technical evaluation.

    Science.gov (United States)

    Coutinho de Paula, Eduardo; Gomes, Júlia Célia Lima; Amaral, Míriam Cristina Santos

    2017-07-01

    The adverse impacts caused by the disposal of thousands of tonnes per annum of reverse osmosis (RO) membranes modules have grown dramatically around the world. The objective of this study was to evaluate the technical feasibility of recycling by chemical oxidation of end-of-life RO membranes for applications in other separation processes with specifications less rigorous. The recycling technique consisted in to cause a membrane exposition with oxidant solutions in order to remove its aromatic polyamide layer and subsequent conversion to a porous membrane. The recycling technique was evaluated by water permeability and salt rejection tests before and after the oxidative treatments. Initially, membranes' chemical cleaning and pretreatment procedures were assessed. Among factors evaluated, the oxidizing agent, its concentration and pH, associated with the oxidative treatment time, showed important influence on the oxidation of the membranes. Results showed that sodium hypochlorite and potassium permanganate are efficient agents for the membrane recycling. The great increased permeability and decreased salt rejection indicated changes on membranes' selective properties. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and contact angle characterization techniques revealed marked changes on the main membranes' physical-chemical properties, such as morphology, roughness and hydrophobicity. Reuse of produced effluents and fouling tendency of recycled membranes were also evaluated.

  13. Treatment of toxic and hazardous organic wastes by wet oxidation process with oxygenated water at low temperature; Trattamento dei rifiuti tossici e nocivi organici mediante il processo di ossidazione ad umido con acqua ossigenata a bassa temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Piccinno, T; Salluzzo, A; Nardi, L [ENEA - Dipartimento Ciclo del Combustibile, Centro Ricerche Energia, Casaccia (Italy); Gili, M; Luce, A; Troiani, F [ENEA - Dipartimento Ciclo del Combustibile, Centro Ricerche Energia, Saluggia (Italy); Cornacchia, G [ENEA - Dipartimento Ciclo del Combustibile, Centro Ricerche Energia, Trisaia (Italy)

    1989-11-15

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

  14. Selective Electrochemical Generation of Hydrogen Peroxide from Water Oxidation

    DEFF Research Database (Denmark)

    Viswanathan, Venkatasubramanian; Hansen, Heine Anton; Nørskov, Jens K.

    2015-01-01

    evolution and form hydrogen peroxide. Using density functional theory calculations, we show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e(-) water oxidation to H2O2 and the 4e(-) oxidation to O2. We show that materials which bind oxygen intermediates...... sufficiently weakly, such as SnO2, can activate hydrogen peroxide evolution. We present a rational design principle for the selectivity in electrochemical water oxidation and identify new material candidates that could perform H2O2 evolution selectively....

  15. Experimental PIV and CFD studies of UV-peroxide advanced oxidation reactors for water treatment

    International Nuclear Information System (INIS)

    Sozzi, A.; Taghipour, F.

    2004-01-01

    An experimental and numerical study of the flow characteristics in an annular UV reactor, as used for drinking water disinfection or Advanced Oxidation Processes, was carried out using Particle Image Velocimetry (PIV) and Computational Fluid Dynamics (CFD). The influence of different turbulence models and mesh structures on the CFD results was investigated. By qualitative and quantitative comparison of CFD and PIV experimental data, it was shown that the Realizable k-e- turbulence model is best suited for simulating the hydrodynamics of this geometry. (author)

  16. Development of sustainable water treatment technology using scientifically based calculated indexes of source water quality indicators

    Directory of Open Access Journals (Sweden)

    А. С. Трякина

    2017-10-01

    Full Text Available The article describes selection process of sustainable technological process flow chart for water treatment procedure developed on scientifically based calculated indexes of quality indicators for water supplied to water treatment facilities. In accordance with the previously calculated values of the indicators of the source water quality, the main purification facilities are selected. A more sustainable flow chart for the modern water quality of the Seversky Donets-Donbass channel is a two-stage filtering with contact prefilters and high-rate filters. The article proposes a set of measures to reduce such an indicator of water quality as permanganate oxidation. The most suitable for these purposes is sorption purification using granular activated carbon for water filtering. The increased water hardness is also quite topical. The method of ion exchange on sodium cation filters was chosen to reduce the water hardness. We also evaluated the reagents for decontamination of water. As a result, sodium hypochlorite is selected for treatment of water, which has several advantages over chlorine and retains the necessary aftereffect, unlike ozone. A technological flow chart with two-stage purification on contact prefilters and two-layer high-rate filters (granular activated carbon - quartz sand with disinfection of sodium hypochlorite and softening of a part of water on sodium-cation exchangers filters is proposed. This technological flow chart of purification with any fluctuations in the quality of the source water is able to provide purified water that meets the requirements of the current sanitary-hygienic standards. In accordance with the developed flow chart, guidelines and activities for the reconstruction of the existing Makeevka Filtering Station were identified. The recommended flow chart uses more compact and less costly facilities, as well as additional measures to reduce those water quality indicators, the values of which previously were in

  17. Efficient electrochemical water oxidation in neutral and near-neutral systems by nanoscale silver-oxide catalyst

    KAUST Repository

    Joya, Khurram Saleem; Ahmad, Zahoor; Joya, Yasir Faheem; Garcia Esparza, Angel T.; de Groot, Huub

    2016-01-01

    In electrocatalytic water splitting systems pursuing for renewable energy using sun light, developing robust, stable and easy accessible materials operating under mild chemical conditions is pivotal. We present here unique nano-particulate type silver-oxide (AgOx-NP) based robust and highly stable electrocatalyst for efficient water oxidation. The AgOx-NP is generated in situ in a HCO3–/CO2 system under benign conditions. Mircographs show that they exhibit nanoscale box type squared nano-bipyramidal configuration. The oxygen generation is initiated at low overpotential, and a sustained O2 evolution current density of > 1.1 mA cm–2 is achieved during prolonged-period water electrolysis. The AgOx-NP electrocatalyst performs exceptionally well in metal-ions free neutral or near-neutral carbonate, phosphate and borate buffers relative to recently reported Co-oxide and Ni-oxide based heterogeneous electrocatalysts, which are unstable in metal-ions free electrolyte and tend to degrade with time and lose catalytic performance during long-term experimental tests.

  18. Efficient electrochemical water oxidation in neutral and near-neutral systems by nanoscale silver-oxide catalyst

    KAUST Repository

    Joya, Khurram Saleem

    2016-07-19

    In electrocatalytic water splitting systems pursuing for renewable energy using sun light, developing robust, stable and easy accessible materials operating under mild chemical conditions is pivotal. We present here unique nano-particulate type silver-oxide (AgOx-NP) based robust and highly stable electrocatalyst for efficient water oxidation. The AgOx-NP is generated in situ in a HCO3–/CO2 system under benign conditions. Mircographs show that they exhibit nanoscale box type squared nano-bipyramidal configuration. The oxygen generation is initiated at low overpotential, and a sustained O2 evolution current density of > 1.1 mA cm–2 is achieved during prolonged-period water electrolysis. The AgOx-NP electrocatalyst performs exceptionally well in metal-ions free neutral or near-neutral carbonate, phosphate and borate buffers relative to recently reported Co-oxide and Ni-oxide based heterogeneous electrocatalysts, which are unstable in metal-ions free electrolyte and tend to degrade with time and lose catalytic performance during long-term experimental tests.

  19. Strongly oxidizing perylene-3,4-dicarboximides for use in water oxidation photoelectrochemical cells

    Energy Technology Data Exchange (ETDEWEB)

    Lindquist, Rebecca J.; Phelan, Brian T.; Reynal, Anna; Margulies, Eric A.; Shoer, Leah E.; Durrant, James R.; Wasielewski, Michael R.

    2016-01-01

    Perylene-3,4-dicarboximide (PMI) based chromophores have demonstrated the ability to inject electrons into TiO2 for dye-sensitized solar cell applications and to accept electrons from metal complexes relevant to water oxidation, but they are nearly unexplored for use in photoelectrochemical cells (PECs) for solar fuels generation. A series of related PMIs with high oxidation potentials and carboxylate binding groups was synthesized and investigated for this purpose. Charge injection and recombination dynamics were measured using transient absorption (TA) spectroscopy on the picosecond to second timescales. The dynamics and electron injection yields were correlated with the PMI energetics and structures. Injection began in less than 1 ps for the dye with the best performance and a significant charge-separated state yield remained at long times. Finally, this chromophore was used to oxidize a covalently bound water oxidation precatalyst following electron injection into TiO2 to demonstrate the utility of the dyes for use in PECs.

  20. Formation of assimilable organic carbon during oxidation of natural waters with ozone, chlorine dioxide, chlorine, permanganate, and ferrate.

    Science.gov (United States)

    Ramseier, Maaike K; Peter, Andreas; Traber, Jacqueline; von Gunten, Urs

    2011-02-01

    Five oxidants, ozone, chlorine dioxide, chlorine, permanganate, and ferrate were studied with regard to the formation of assimilable organic carbon (AOC) and oxalate in absence and presence of cyanobacteria in lake water matrices. Ozone and ferrate formed significant amounts of AOC, i.e. more than 100 μg/L AOC were formed with 4.6 mg/L ozone and ferrate in water with 3.8 mg/L dissolved organic carbon. In the same water samples chlorine dioxide, chlorine, and permanganate produced no or only limited AOC. When cyanobacterial cells (Aphanizomenon gracile) were added to the water, an AOC increase was detected with ozone, permanganate, and ferrate, probably due to cell lysis. This was confirmed by the increase of extracellular geosmin, a substance found in the selected cyanobacterial cells. AOC formation by chlorine and chlorine dioxide was not affected by the presence of the cells. The formation of oxalate upon oxidation was found to be a linear function of the oxidant consumption for all five oxidants. The following molar yields were measured in three different water matrices based on oxidant consumed: 2.4-4.4% for ozone, 1.0-2.8% for chlorine dioxide and chlorine, 1.1-1.2% for ferrate, and 11-16% for permanganate. Furthermore, oxalate was formed in similar concentrations as trihalomethanes during chlorination (yield ∼ 1% based on chlorine consumed). Oxalate formation kinetics and stoichiometry did not correspond to the AOC formation. Therefore, oxalate cannot be used as a surrogate for AOC formation during oxidative water treatment. Copyright © 2010 Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    In this study we present results on the application of advanced oxidation systems for effective and non-toxic oxidation of poly(ethylene terephthalate) track-etched membranes (PET TeMs) to improve their wettability and water transport properties. Two oxidizing systems: H 2 O 2 under UV irradiation (H 2 O 2 /UV) and Fenton system under visible light (Fenton/H 2 O 2 /Vis) were compared. The surface of functionalized PET TeMs was characterized by using colorimetric assay, contact angle measurements and X-ray photoelectron spectroscopy (XPS). Results clearly showed that water permeability of PET TeMs treated with H 2 O 2 /UV was improved by 28 ± 5% compared with etched-only membrane, the same parameter was found to increase by 13 ± 4% in the case of Fenton/H 2 O 2 /Vis treatment. The proposed oxidation technique is very simple, environment friendly and not requiring special equipment or expensive chemicals. The surface hydrophilicity of the membranes stored for 360 days in air between paper sheets was analyzed by contact angle test, colorimetric assay to measure concentration of carboxylic groups on the surface with toluidine blue and XPS analysis. The hydrophilic properties of oxidized PET TeMs were found to be stable for a long period of time.

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

    Science.gov (United States)

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

    2015-12-01

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

  3. Biosorption treatment of brackish water

    International Nuclear Information System (INIS)

    Rizwan, M.; Ali, M.; Tariq, M.I.; Rehman, F.U.; Karim, A.; Makshoof, M.; Farooq, R.

    2010-01-01

    Biosorptivity of different agricultural wastes have been evaluated for the treatment of brackish water and a new method, based on the principle of bio-sorption has been described. Wastes of the Saccharum officinarum, Moringa oleifera, Triticum aestivcum and Oryza sativa have been used in raw forms as well as after converting them into ash and activated carbon as biosorbents for treatment of brackish water in this study. Samples of brackish water have been analyzed before and after treatment for quality control parameters of water. A significant Improvement has been observed in quality control parameters of water after treatment. pH of the water samples slightly increased from 7.68 to 7.97 with different treatments. A substantial decrease in conductivity,. TDS, TH, concentrations of cations and anions was observed in the samples of brackish water after treatment with different biosorbents. (author)

  4. TECHNOLOGICAL PROCESS ASSESSMENT OF THE DRINKING WATER TREATMENT AT TARGU-MURES WATER TREATMENT PLANT

    Directory of Open Access Journals (Sweden)

    CORNELIA DIANA HERTIA

    2011-03-01

    Full Text Available This paper intends to assess the technological process of obtaining drinking water at Targu-Mures water treatment plant. The assessment was performed before changing the technological process and four months were chosen to be analized during 2008: January, April, July and October for its efficiency analysis on treatment steps. Mures River is the water source for the water treatment plant, being characterized by unsteady flow and quality parameters with possible important variability in a very short period of time. The treatment technological process is the classic one, represented by coagulation, sedimentation, filtration and disinfection, but also prechlorination was constantly applied as additional treatment during 2008. Results showed that for the measured parameters, raw water at the water treatment plant fits into class A3 for surface waters, framing dictated by the bacterial load. The treatment processes efficiency is based on the performance calculation for sedimentation, filtration, global and for disinfection, a better conformation degree of technological steps standing out in January in comparison to the other three analyzed months. A variable non-compliance of turbidity and residual chlorine levels in the disinfected water was observed constantly. Previous treatment steps managed to maintain a low level of oxidisability, chlorine consumption and residual chlorine levels being also low. 12% samples were found inconsistent with the national legislation in terms of bacteriological quality. Measures for the water treatment plant retechnologization are taken primarily for hyperchlorination elimination, which currently constitutes a discomfort factor (taste, smell, and a generating factor of chlorination by-products.

  5. Ammonia- and nitrite-oxidizing bacterial communities in a pilot-scale chloraminated drinking water distribution system.

    Science.gov (United States)

    Regan, John M; Harrington, Gregory W; Noguera, Daniel R

    2002-01-01

    Nitrification in drinking water distribution systems is a common operational problem for many utilities that use chloramines for secondary disinfection. The diversity of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the distribution systems of a pilot-scale chloraminated drinking water treatment system was characterized using terminal restriction fragment length polymorphism (T-RFLP) analysis and 16S rRNA gene (ribosomal DNA [rDNA]) cloning and sequencing. For ammonia oxidizers, 16S rDNA-targeted T-RFLP indicated the presence of Nitrosomonas in each of the distribution systems, with a considerably smaller peak attributable to Nitrosospira-like AOB. Sequences of AOB amplification products aligned within the Nitrosomonas oligotropha cluster and were closely related to N. oligotropha and Nitrosomonas ureae. The nitrite-oxidizing communities were comprised primarily of Nitrospira, although Nitrobacter was detected in some samples. These results suggest a possible selection of AOB related to N. oligotropha and N. ureae in chloraminated systems and demonstrate the presence of NOB, indicating a biological mechanism for nitrite loss that contributes to a reduction in nitrite-associated chloramine decay.

  6. CAV-OX (trade name) Cavitation Oxidation Process Magnum Water Technology, Inc. applications analysis report. Report for November 1992-November 1993

    Energy Technology Data Exchange (ETDEWEB)

    Stacy, G.L.

    1994-05-01

    The CAV-OX process was developed by magnum Water Technology to destroy organic contaminants in water. The process uses hydrodynamic cavitation, ultraviolet (UV) radiation, and hydrogen peroxide to oxidize organic compounds present in water at or below milligrams per liter levels. This treatment technology produces no air emissions and generated no sludge or spent media that requires further processing, handling, or disposal. Ideally, the end products are water, carbon dioxide, halides, and in some cases, organic acids. The process uses mercury vapor lamps to generate UV radiation. The principal oxidants in the process, hydroxyl radicals, are produced by hydrodynamic cavitation and direct photolysis of hydrogen peroxide at UV wavelengths.

  7. Oxidation of Inconel 625 superalloy upon treatment with oxygen or hydrogen plasma at high temperature

    Science.gov (United States)

    Vesel, Alenka; Drenik, Aleksander; Elersic, Kristina; Mozetic, Miran; Kovac, Janez; Gyergyek, Tomaz; Stockel, Jan; Varju, Jozef; Panek, Radomir; Balat-Pichelin, Marianne

    2014-06-01

    Initial stages of Inconel 625 superalloy (Ni60Cr30Mo10Ni4Nb1) oxidation upon short treatment with gaseous plasma at different temperatures up to about 1600 K were studied. Samples were treated for different periods up to a minute by oxygen or hydrogen plasma created with a microwave discharge in the standing-wave mode at a pressure of 40 Pa and a power 500 W. Simultaneous heating of the samples was realized by focusing concentrated solar radiation from a 5 kW solar furnace directly onto the samples. The morphological changes upon treatment were monitored using scanning electron microscopy, compositional depth profiling was performed using Auger electron spectroscopy, while structural changes were determined by X-ray diffraction. The treatment in oxygen plasma caused formation of metal oxide clusters of three dimensional crystallites initially rich in nickel oxide with the increasing chromium oxide content as the temperature was increasing. At about 1100 K iron and niobium oxides prevailed on the surface causing a drop of the material emissivity at 5 μm. Simultaneously the NiCr2O4 compound started growing at the interface between the oxide film and bulk alloy and the compound persisted up to temperatures close to the Inconel melting point. Intensive migration of minority alloying elements such as Fe and Ti was observed at 1600 K forming mixed surface oxides of sub-micrometer dimensions. The treatment in hydrogen plasma with small admixture of water vapor did not cause much modification unless the temperature was close to the melting point. At such conditions aluminum segregated on the surface and formed well-defined Al2O3 crystals.

  8. Closed recirculation-Water treatment

    International Nuclear Information System (INIS)

    Hamza, Hamza B.; Ben Ali, Salah; Saad, Mohamed A.; Traish, Massud R.

    2005-01-01

    This water treatment is a practical work applied in the center, for a closed recirculation-water system. The system had experienced a serious corrosion problem, due to the use of inadequate water. This work includes chemical preparation for the system. Water treatment, special additives, and follow-up, which resulted in the stability of the case. This work can be applied specially for closed recirculation warm, normal, and chilled water. (author)

  9. Electrometallurgical treatment of oxide spent fuels

    International Nuclear Information System (INIS)

    Karell, E. J.

    1999-01-01

    The Department of Energy (DOE) inventory of spent nuclear fuel contains a wide variety of oxide fuel types that may be unsuitable for direct repository disposal in their current form. The molten-salt electrometallurgical treatment technique developed by Argonne National Laboratory (ANL) has the potential to simplify preparing and qualifying these fuels for disposal by converting them into three uniform product streams: uranium metal, a metal waste form, and a ceramic waste form. This paper describes the major steps in the electrometallurgical treatment process for oxide fuels and provides the results of recent experiments performed to develop and scale up the process

  10. Water formation via HCl oxidation on Cu(1 0 0)

    Energy Technology Data Exchange (ETDEWEB)

    Suleiman, Ibrahim A., E-mail: isuleman@taibahu.edu.sa [College of Engineering, Taibah University, Yanbu 41911 (Saudi Arabia); Radny, Marian W. [School of Mathematical and Physical Sciences, The University of Newcastle, Callaghan, NSW 2308 (Australia); Institute of Physics, Poznan University of Technology, 62-956 Poznan (Poland); Gladys, Michael J.; Smith, Phillip V. [School of Mathematical and Physical Sciences, The University of Newcastle, Callaghan, NSW 2308 (Australia); Mackie, John C. [School of Engineering, The University of Newcastle, Callaghan, NSW 2308 (Australia); School of Chemistry, The University of Sydney (Australia); Stockenhuber, Michael; Kennedy, Eric M. [School of Engineering, The University of Newcastle, Callaghan, NSW 2308 (Australia); Dlugogorski, Bogdan Z. [School of Engineering, The University of Newcastle, Callaghan, NSW 2308 (Australia); School of Engineering and Information Technology, Murdoch University, Perth (Australia)

    2014-04-01

    Graphical abstract: This work investigates water formation on the Cu(1 0 0) surface via HCl oxidation using density functional theory and periodic slabs. We show that there are two different pathways for water formation on the surface depending on the temperature and oxygen coverage. - Highlights: • Pre-adsorbed chlorine increases the stability of water on Cu(1 0 0). • Two different pathways describe water formation on Cu(1 0 0) via HCl oxidation. • The mechanism of H{sub 2}O formation depends on the temperature and oxygen coverage. - Abstract: Using density functional theory and periodic slabs, we have studied water formation via HCl oxidation on the Cu(1 0 0) surface. We show that while adsorbed chlorine increases the stability of water on the Cu(1 0 0) surface, water molecules dissociate immediately when located next to an oxygen atom. We also show that these competing interactions, when arising from HCl reacting with oxygen on Cu(1 0 0), lead to water formation according to two different pathways depending on the temperature and oxygen coverage.

  11. Atomic-scale Studies of Uranium Oxidation and Corrosion by Water Vapour.

    Science.gov (United States)

    Martin, T L; Coe, C; Bagot, P A J; Morrall, P; Smith, G D W; Scott, T; Moody, M P

    2016-07-12

    Understanding the corrosion of uranium is important for its safe, long-term storage. Uranium metal corrodes rapidly in air, but the exact mechanism remains subject to debate. Atom Probe Tomography was used to investigate the surface microstructure of metallic depleted uranium specimens following polishing and exposure to moist air. A complex, corrugated metal-oxide interface was observed, with approximately 60 at.% oxygen content within the oxide. Interestingly, a very thin (~5 nm) interfacial layer of uranium hydride was observed at the oxide-metal interface. Exposure to deuterated water vapour produced an equivalent deuteride signal at the metal-oxide interface, confirming the hydride as originating via the water vapour oxidation mechanism. Hydroxide ions were detected uniformly throughout the oxide, yet showed reduced prominence at the metal interface. These results support a proposed mechanism for the oxidation of uranium in water vapour environments where the transport of hydroxyl species and the formation of hydride are key to understanding the observed behaviour.

  12. Atomic-scale Studies of Uranium Oxidation and Corrosion by Water Vapour

    Science.gov (United States)

    Martin, T. L.; Coe, C.; Bagot, P. A. J.; Morrall, P.; Smith, G. D. W.; Scott, T.; Moody, M. P.

    2016-07-01

    Understanding the corrosion of uranium is important for its safe, long-term storage. Uranium metal corrodes rapidly in air, but the exact mechanism remains subject to debate. Atom Probe Tomography was used to investigate the surface microstructure of metallic depleted uranium specimens following polishing and exposure to moist air. A complex, corrugated metal-oxide interface was observed, with approximately 60 at.% oxygen content within the oxide. Interestingly, a very thin (~5 nm) interfacial layer of uranium hydride was observed at the oxide-metal interface. Exposure to deuterated water vapour produced an equivalent deuteride signal at the metal-oxide interface, confirming the hydride as originating via the water vapour oxidation mechanism. Hydroxide ions were detected uniformly throughout the oxide, yet showed reduced prominence at the metal interface. These results support a proposed mechanism for the oxidation of uranium in water vapour environments where the transport of hydroxyl species and the formation of hydride are key to understanding the observed behaviour.

  13. Development of a household waste treatment subsystem, volume 1. [with water conservation features

    Science.gov (United States)

    Gresko, T. M.; Murray, R. W.

    1973-01-01

    The domestic waste treatment subsystem was developed to process the daily liquid and non-metallic solid wastes provided by a family of four people. The subsystem was designed to be connected to the sewer line of a household which contained water conservation features. The system consisted of an evaporation technique to separate liquids from solids, an incineration technique for solids reduction, and a catalytic oxidizer for eliminating noxious gases from evaporation and incineration processes. All wastes were passed through a grinder which masticated the solids and deposited them in a settling tank. The liquids were transferred through a cleanable filter into a holding tank. From here the liquids were sprayed into an evaporator and a spray chamber where evaporation occurred. The resulting vapors were processed by catalytic oxidation. Water and latent energy were recovered in a combination evaporator/condenser heat exchanger. The solids were conveyed into an incinerator and reduced to ash while the incineration gases were passed through the catalytic oxidizer along with the processed water vapor.

  14. Advanced oxidation treatment of high strength bilge and aqueous petroleum waste

    Energy Technology Data Exchange (ETDEWEB)

    Hulsey, R.A.; Kobylinski, E.A. [Black and Veatch, Kansas City, MO (United States); Leach, B. [EEC, Inc., Virginia Beach, VA (United States); Pearce, L. [TRITECH, Greensboro, NC (United States)

    1996-11-01

    The Craney Island Fuel Depot is the largest US Navy fuel terminal in the continental US. Services provided at this facility include fuel storage (current capacity is 1.5 million barrels), fuel reclamation (recovery of oil from oily wastewater), and physical/chemical treatment for the removal of residual oil from bilge water and from aqueous petroleum waste. Current wastewater treatment consists of storage/equalization, oil/water separation, dissolved air flotation, sand filtration, and carbon adsorption. The Navy initiated this study to comply with the State requirement that its existing physical/chemical oily wastewater treatment plant be upgraded to remove soluble organics and produce an effluent which would meet acute toxicity limits. The pilot tests conducted during the study included several variations of chemical and biological wastewater treatment processes. While biological treatment alone was capable of meeting the proposed BOD limit of 26 mg/L, the study showed that the effluent of the biological process contained a high concentration of refractory (nonbiodegradable) organics and could not consistently meet the proposed limits for COD and TOC when treating high-strength wastewater. Additional tests were conducted with advanced oxidation processes (AOPs). AOPs were evaluated for use as independent treatment processes as well as polishing processes following biological treatment. The AOP processes used for this study included combinations of ozone (O{sub 3}) ultraviolet radiation (UV), and hydrogen peroxide (H{sub 2}O{sub 2}).

  15. Photosynthetic water oxidation: binding and activation of substrate waters for O-O bond formation.

    Science.gov (United States)

    Vinyard, David J; Khan, Sahr; Brudvig, Gary W

    2015-01-01

    Photosynthetic water oxidation occurs at the oxygen-evolving complex (OEC) of Photosystem II (PSII). The OEC, which contains a Mn4CaO5 inorganic cluster ligated by oxides, waters and amino-acid residues, cycles through five redox intermediates known as S(i) states (i = 0-4). The electronic and structural properties of the transient S4 intermediate that forms the O-O bond are not well understood. In order to gain insight into how water is activated for O-O bond formation in the S4 intermediate, we have performed a detailed analysis of S-state dependent substrate water binding kinetics taking into consideration data from Mn coordination complexes. This analysis supports a model in which the substrate waters are both bound as terminal ligands and react via a water-nucleophile attack mechanism.

  16. Removal of emerging contaminants in sewage water subjected to advanced oxidation with ozone.

    Science.gov (United States)

    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. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Highly efficient bioinspired molecular Ru water oxidation catalysts with negatively charged backbone ligands.

    Science.gov (United States)

    Duan, Lele; Wang, Lei; Li, Fusheng; Li, Fei; Sun, Licheng

    2015-07-21

    The oxygen evolving complex (OEC) of the natural photosynthesis system II (PSII) oxidizes water to produce oxygen and reducing equivalents (protons and electrons). The oxygen released from PSII provides the oxygen source of our atmosphere; the reducing equivalents are used to reduce carbon dioxide to organic products, which support almost all organisms on the Earth planet. The first photosynthetic organisms able to split water were proposed to be cyanobacteria-like ones appearing ca. 2.5 billion years ago. Since then, nature has chosen a sustainable way by using solar energy to develop itself. Inspired by nature, human beings started to mimic the functions of the natural photosynthesis system and proposed the concept of artificial photosynthesis (AP) with the view to creating energy-sustainable societies and reducing the impact on the Earth environments. Water oxidation is a highly energy demanding reaction and essential to produce reducing equivalents for fuel production, and thereby effective water oxidation catalysts (WOCs) are required to catalyze water oxidation and reduce the energy loss. X-ray crystallographic studies on PSII have revealed that the OEC consists of a Mn4CaO5 cluster surrounded by oxygen rich ligands, such as oxyl, oxo, and carboxylate ligands. These negatively charged, oxygen rich ligands strongly stabilize the high valent states of the Mn cluster and play vital roles in effective water oxidation catalysis with low overpotential. This Account describes our endeavors to design effective Ru WOCs with low overpotential, large turnover number, and high turnover frequency by introducing negatively charged ligands, such as carboxylate. Negatively charged ligands stabilized the high valent states of Ru catalysts, as evidenced by the low oxidation potentials. Meanwhile, the oxygen production rates of our Ru catalysts were improved dramatically as well. Thanks to the strong electron donation ability of carboxylate containing ligands, a seven

  18. Advanced oxidation processes for treatment of petroleum refinery sour waters; Processos oxidativos avancados para tratamento de aguas acidas de refinaria de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Antonio V.; Coelho, Alessandra D.; Sant' Anna Junior, Geraldo L.; Dezotti, Marcia [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Quimica

    2004-07-01

    The characteristics of the waste water generated by the petroleum refineries are related to the type and amount of processed oil, to the nature and the efficiency of the refining operation. The effluents are composed basically of oily waters, originating from of the contact with the oil. Among them, the current of sour water is one of the most preoccupying due to its composition: sulfide, ammonia, mercaptans, phenol, dissolved oil, basic pH, dissolved organic carbon (DOC) and chemical oxygen demand (COD) high. The aim of this work was to evaluate the advanced oxidation processes to degrade sour water (UV radiation, H{sub 2}O{sub 2} and H{sub 2}O{sub 2}/UV, photocatalysis, Fenton and photo-Fenton). All process, except Fenton and photo-Fenton, did not supply satisfactory results, reducing 25% of initial DOC, which it is of 450 mg/L. The results using the Fenton process reached removal of 50% of the initial COD, and when photo- Fenton process obtaining removal of 90%. The processes Fenton and photo-Fenton were shown capable to degrade this kind of waste water, minimizing the environmental problems and corrosion, operating as a pre-treatment for the biological system, or acting alone to degrade the organic matter contained, seeking the water reuse. The effluent used in this work came from Duque de Caxias Refinery (Reduc)/PETROBRAS. (author)

  19. Treatment of slaughter wastewater by coagulation sedimentation-anaerobic biological filter and biological contact oxidation process

    Science.gov (United States)

    Sun, M.; Yu, P. F.; Fu, J. X.; Ji, X. Q.; Jiang, T.

    2017-08-01

    The optimal process parameters and conditions for the treatment of slaughterhouse wastewater by coagulation sedimentation-AF - biological contact oxidation process were studied to solve the problem of high concentration organic wastewater treatment in the production of small and medium sized slaughter plants. The suitable water temperature and the optimum reaction time are determined by the experiment of precipitation to study the effect of filtration rate and reflux ratio on COD and SS in anaerobic biological filter and the effect of biofilm thickness and gas water ratio on NH3-N and COD in biological contact oxidation tank, and results show that the optimum temperature is 16-24°C, reaction time is 20 min in coagulating sedimentation, the optimum filtration rate is 0.6 m/h, and the optimum reflux ratio is 300% in anaerobic biological filter reactor. The most suitable biological film thickness range of 1.8-2.2 mm and the most suitable gas water ratio is 12:1-14:1 in biological contact oxidation pool. In the coupling process of continuous operation for 80 days, the average effluent’s mass concentrations of COD, TP and TN were 15.57 mg/L, 40 mg/L and 0.63 mg/L, the average removal rates were 98.93%, 86.10%, 88.95%, respectively. The coupling process has stable operation effect and good effluent quality, and is suitable for the industrial application.

  20. Water Supply Treatment Sustainability of Semambu Water Supply Treatment Process - Water Footprint Approach

    Science.gov (United States)

    Aziz, Edriyana A.; Malek, Marlinda Abdul; Moni, Syazwan N.; Hadi, Iqmal H.; Zulkifli, Nabil F.

    2018-03-01

    In this study, the assessment by using Water Footprint (WF) approach was conducted to assess water consumption within the water supply treatment process (WSTP) services of Semambu Water Treatment Plant (WTP). Identification of the type of WF at each stage of WSTP was carried out and later the WF accounting for the period 2010 – 2016 was calculated. Several factors that might influence the accounting such as population, and land use. The increasing value of total WF per year was due to the increasing water demand from population and land use activities. However, the pattern of rainfall intensity from the monsoonal changes was not majorly affected the total amount of WF per year. As a conclusion, if the value of WF per year keeps increasing due to unregulated development in addition to the occurrences of climate changing, the intake river water will be insufficient and may lead to water scarcity. The findings in this study suggest actions to reduce the WF will likely have a great impact on freshwater resources availability and sustainability.

  1. Effect of tin oxide nano particles and heat treatment on decay resistance and physical properties of beech wood (Fagus orientalis

    Directory of Open Access Journals (Sweden)

    Maryam Ghorbani

    2014-11-01

    Full Text Available This research was conducted to investigate the effect of Tin oxide nanoparticles and heat treatment on decay resistance and physical properties of beech wood. Biological and physical test samples were prepared according to EN-113 and ASTM-D4446-05 standards respectively. Samples were classified into 4 groups: control, impregnation with Tin oxide nanoparticles, heat treatment and nano-heat treatment. Impregnation with Tin oxide nano at 5000ppm concentration was carried out in the cylinder according to Bethell method. Then, samples were heated at 140, 160 and 185˚C for 2 and 4 hours. According to results, decay resistance improved with increasing time and temperature of heat treatment. Least weight loss showed 46.39% reduction in nano-heat samples treated at 180˚C for 4 hours in comparison with control at highest weight loss. Nano-heat treated samples demonstrated the maximum amount of water absorption without significant difference with control and nanoparticles treated samples. Increase in heat treatment temperature reduced water absorption so that it is revealed 47.8% reduction in heat treated samples at 180°C for 4h after 24h immersion in water. In nano-heat treated samples at 180˚C for 2h was measured least volume swelling. Volume swelling in nano-treated samples decreased 8.7 and 22.76% after 2 and 24 h immersion in comparison with the control samples respectively.

  2. Sizing criteria for a low footprint passive mine water treatment system.

    Science.gov (United States)

    Sapsford, D J; Williams, K P

    2009-02-01

    The objective of this paper is to present data from a novel vertical flow mine water treatment system, demonstrate how these data can be used to generate sizing formulae for this technology, and present a comparison between the size of system based on these formulae and those of conventionally designed passive systems. The paper focuses on passive treatment of circum-neutral ferruginous mine waters bearing up to 50 mgl(-1) of iron in either ferrous or ferric form. The Vertical Flow Reactor (VFR) operates by passing mine water down through an accreting bed of ochre, the ochre bed being responsible for the intensification of iron removal by self-filtration and/or autocatalytic iron oxidation and precipitation. Key to the design and operation of the VFR system is the decrease in permeability in this ochre bed over time. The paper demonstrates that the VFR system can remove iron at many times the 10 g/m2/day removal rate - an often employed figure for the sizing of aerobic settling ponds and wetlands. The paper demonstrates that VFRs are viable and novel passive treatment system for mine waters with a smaller footprint than conventional systems.

  3. An overview on the removal of synthetic dyes from water by electrochemical advanced oxidation processes.

    Science.gov (United States)

    Nidheesh, P V; Zhou, Minghua; Oturan, Mehmet A

    2018-04-01

    Wastewater containing dyes are one of the major threats to our environment. Conventional methods are insufficient for the removal of these persistent organic pollutants. Recently much attention has been received for the oxidative removal of various organic pollutants by electrochemically generated hydroxyl radical. This review article aims to provide the recent trends in the field of various Electrochemical Advanced Oxidation Processes (EAOPs) used for removing dyes from water medium. The characteristics, fundamentals and recent advances in each processes namely anodic oxidation, electro-Fenton, peroxicoagulation, fered Fenton, anodic Fenton, photoelectro-Fenton, sonoelectro-Fenton, bioelectro-Fenton etc. have been examined in detail. These processes have great potential to destroy persistent organic pollutants in aqueous medium and most of the studies reported complete removal of dyes from water. The great capacity of these processes indicates that EAOPs constitute a promising technology for the treatment of the dye contaminated effluents. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Myofibrillar protein oxidation affects filament charges, aggregation and water-holding

    NARCIS (Netherlands)

    Bao, Yulong; Boeren, Sjef; Ertbjerg, Per

    2018-01-01

    Hypochlorous acid (HClO) is a strong oxidant that is able to mediate protein oxidation. In order to study the effect of oxidation on charges, aggregation and water-holding of myofibrillar proteins, extracted myofibrils were oxidized by incubation with different concentrations of HClO (0, 1, 5,

  5. Electrochemical treatment of wastewater: A case study of reduction of DNT and oxidation of chlorinated phenols

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, J.D.; Bunce, N.J.; Jedral, W.

    1999-07-01

    Electrochemical treatment is under consideration as a treatment option for several recalcitrant compounds. In this work the authors investigate the oxidation of chlorophenols and the reduction of nitroaromatics. In the case of chlorinated phenols, they explore the problem of anode fouling which has hampered electrolytic treatment of phenolic compounds by examining phenols differing in the extent of chlorination, according to the mechanism of oxidation at different electrode types. Linear sweep voltammograms at a Pt anode were interpreted in terms of deposition of oligomers on the anode surface. Passivation increased in parallel with the uncompensated resistance of the solution and occurred only at potentials at which water is oxidized, suggesting that the formation of the oligomer film involves attack of hydroxyl radicals on electrochemically oxidized substrate. Relative reactivities of congeners were anode-dependent, due to different mechanisms of oxidation: direct electron transfer oxidation at PbO{sub 2} and hydroxyl radical attack at SnO{sub 2} and IrO{sub 2}. Voltammetry of 2,6-dinitrotoluene (DNT) was consistent with literature values. DNT was reduced at several cathodes with the most promising result at Ni-plated Ni wire. At current densities {lt} 0.1 mA cm{sup {minus}2}, current efficiencies {gt} 50% could be achieved with 4-chlorophenol at all three anodes and for 2,6-DNT at Ni-plated Ni wire.

  6. Occurrences and removal of pharmaceuticals and personal care products (PPCPs) in drinking water and water/sewage treatment plants: A review.

    Science.gov (United States)

    Yang, Yi; Ok, Yong Sik; Kim, Ki-Hyun; Kwon, Eilhann E; Tsang, Yiu Fai

    2017-10-15

    In recent years, many of micropollutants have been widely detected because of continuous input of pharmaceuticals and personal care products (PPCPs) into the environment and newly developed state-of-the-art analytical methods. PPCP residues are frequently detected in drinking water sources, sewage treatment plants (STPs), and water treatment plants (WTPs) due to their universal consumption, low human metabolic capability, and improper disposal. When partially metabolized PPCPs are transferred into STPs, they elicit negative effects on biological treatment processes; therefore, conventional STPs are insufficient when it comes to PPCP removal. Furthermore, the excreted metabolites may become secondary pollutants and can be further modified in receiving water bodies. Several advanced treatment systems, including membrane filtration, granular activated carbon, and advanced oxidation processes, have been used for the effective removal of individual PPCPs. This review covers the occurrence patterns of PPCPs in water environments and the techniques adopted for their treatment in STP/WTP unit processes operating in various countries. The aim of this review is to provide a comprehensive summary of the removal and fate of PPCPs in different treatment facilities as well as the optimum methods for their elimination in STP and WTP systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Synergetic effect of copper-plating wastewater as a catalyst for the destruction of acrylonitrile wastewater in supercritical water oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Young Ho; Lee, Hong-shik; Lee, Young-Ho [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, 599 Gwanangno, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Kim, Jaehoon; Kim, Jae-Duck [Supercritical Fluid Research Laboratory, Energy and Environment Research Division, Korea Institute of Science and Technology (KIST), 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Lee, Youn-Woo, E-mail: ywlee@snu.ac.kr [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, 599 Gwanangno, Gwanak-gu, Seoul 151-744 (Korea, Republic of)

    2009-08-15

    A new supercritical water oxidation process for the simultaneous treatment of mixed wastewater containing wastewater from acrylonitrile manufacturing processes and copper-plating processes was investigated using a continuous tubular reactor system. Experiments were carried out at temperatures ranging from 400 to 600 deg. C and a pressure of 25 MPa. The residence time was fixed at 2 s by changing the flow rates of feeds, depending on reaction temperature. The initial total organic carbon (TOC) concentration of the wastewaters and the O{sub 2} concentration at the reactor inlet were kept constant at 0.49 and 0.74 mol/L. It was confirmed that the copper-plating wastewater accelerated the TOC conversion of acrylonitrile wastewater from 17.6% to 67.3% at a temperature of 450 deg. C. Moreover, copper and copper oxide nanoparticles were generated in the process of supercritical water oxidation (SCWO) of mixed wastewater. 99.8% of copper in mixed wastewater was recovered as solid copper and copper oxides at a temperature of 600 deg. C, with their average sizes ranging from 150 to 160 nm. Our study showed that SCWO provides a synergetic effect for simultaneous treatment of acrylonitrile and copper-plating wastewater. During the reaction, the oxidation rate of acrylonitrile wastewater was enhanced due to the in situ formation of nano-catalysts of copper and/or copper oxides, while the exothermic decomposition of acrylonitrile wastewater supplied enough heat for the recovery of solid copper and copper oxides from copper-plating wastewater. The synergetic effect of wastewater treatment by the newly proposed SCWO process leads to full TOC conversion, color removal, detoxification, and odor elimination, as well as full recovery of copper.

  8. Dissolved organic nitrogen and its biodegradable portion in a water treatment plant with ozone oxidation.

    Science.gov (United States)

    Wadhawan, Tanush; Simsek, Halis; Kasi, Murthy; Knutson, Kristofer; Prüβ, Birgit; McEvoy, John; Khan, Eakalak

    2014-05-01

    Biodegradability of dissolved organic nitrogen (DON) has been studied in wastewater, freshwater and marine water but not in drinking water. Presence of biodegradable DON (BDON) in water prior to and after chlorination may promote formation of nitrogenous disinfectant by-products and growth of microorganisms in the distribution system. In this study, an existing bioassay to determine BDON in wastewater was adapted and optimized, and its application was tested on samples from four treatment stages of a water treatment plant including ozonation and biologically active filtration. The optimized bioassay was able to detect BDON in 50 μg L(-1) as N of glycine and glutamic solutions. BDON in raw (144-275 μg L(-1) as N), softened (59-226 μg L(-1) as N), ozonated (190-254 μg L(-1) as N), and biologically filtered (17-103 μg L(-1) as N) water samples varied over a sampling period of 2 years. The plant on average removed 30% of DON and 68% of BDON. Ozonation played a major role in increasing the amount of BDON (31%) and biologically active filtration removed 71% of BDON in ozonated water. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Methane oxidation coupled to oxygenic photosynthesis in anoxic waters

    Science.gov (United States)

    Milucka, Jana; Kirf, Mathias; Lu, Lu; Krupke, Andreas; Lam, Phyllis; Littmann, Sten; Kuypers, Marcel MM; Schubert, Carsten J

    2015-01-01

    Freshwater lakes represent large methane sources that, in contrast to the Ocean, significantly contribute to non-anthropogenic methane emissions to the atmosphere. Particularly mixed lakes are major methane emitters, while permanently and seasonally stratified lakes with anoxic bottom waters are often characterized by strongly reduced methane emissions. The causes for this reduced methane flux from anoxic lake waters are not fully understood. Here we identified the microorganisms and processes responsible for the near complete consumption of methane in the anoxic waters of a permanently stratified lake, Lago di Cadagno. Interestingly, known anaerobic methanotrophs could not be detected in these waters. Instead, we found abundant gamma-proteobacterial aerobic methane-oxidizing bacteria active in the anoxic waters. In vitro incubations revealed that, among all the tested potential electron acceptors, only the addition of oxygen enhanced the rates of methane oxidation. An equally pronounced stimulation was also observed when the anoxic water samples were incubated in the light. Our combined results from molecular, biogeochemical and single-cell analyses indicate that methane removal at the anoxic chemocline of Lago di Cadagno is due to true aerobic oxidation of methane fuelled by in situ oxygen production by photosynthetic algae. A similar mechanism could be active in seasonally stratified lakes and marine basins such as the Black Sea, where light penetrates to the anoxic chemocline. Given the widespread occurrence of seasonally stratified anoxic lakes, aerobic methane oxidation coupled to oxygenic photosynthesis might have an important but so far neglected role in methane emissions from lakes. PMID:25679533

  10. Oxidation of Inconel 625 superalloy upon treatment with oxygen or hydrogen plasma at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Vesel, Alenka; Drenik, Aleksander; Elersic, Kristina; Mozetic, Miran; Kovac, Janez [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Gyergyek, Tomaz [University of Ljubljana, Faculty of Electrical Engineering, Trzaska 25, SI-1000 Ljubljana (Slovenia); Stockel, Jan; Varju, Jozef; Panek, Radomir [Institute of Plasma Physics, Academy of Sciences of the Czech Republic, Ze Slovankou 3, Praha 8 (Czech Republic); Balat-Pichelin, Marianne, E-mail: marianne.balat@promes.cnrs.fr [PROMES-CNRS Laboratory, 7 rue du four solaire, 66120 Font Romeu Odeillo (France)

    2014-06-01

    Initial stages of Inconel 625 superalloy (Ni{sub 60}Cr{sub 30}Mo{sub 10}Ni{sub 4}Nb{sub 1}) oxidation upon short treatment with gaseous plasma at different temperatures up to about 1600 K were studied. Samples were treated for different periods up to a minute by oxygen or hydrogen plasma created with a microwave discharge in the standing-wave mode at a pressure of 40 Pa and a power 500 W. Simultaneous heating of the samples was realized by focusing concentrated solar radiation from a 5 kW solar furnace directly onto the samples. The morphological changes upon treatment were monitored using scanning electron microscopy, compositional depth profiling was performed using Auger electron spectroscopy, while structural changes were determined by X-ray diffraction. The treatment in oxygen plasma caused formation of metal oxide clusters of three dimensional crystallites initially rich in nickel oxide with the increasing chromium oxide content as the temperature was increasing. At about 1100 K iron and niobium oxides prevailed on the surface causing a drop of the material emissivity at 5 μm. Simultaneously the NiCr{sub 2}O{sub 4} compound started growing at the interface between the oxide film and bulk alloy and the compound persisted up to temperatures close to the Inconel melting point. Intensive migration of minority alloying elements such as Fe and Ti was observed at 1600 K forming mixed surface oxides of sub-micrometer dimensions. The treatment in hydrogen plasma with small admixture of water vapor did not cause much modification unless the temperature was close to the melting point. At such conditions aluminum segregated on the surface and formed well-defined Al{sub 2}O{sub 3} crystals.

  11. As(III) oxidation by MnO2 during groundwater treatment.

    Science.gov (United States)

    Gude, J C J; Rietveld, L C; van Halem, D

    2017-03-15

    The top layer of natural rapid sand filtration was found to effectively oxidise arsenite (As(III)) in groundwater treatment. However, the oxidation pathway has not yet been identified. The aim of this study was to investigate whether naturally formed manganese oxide (MnO 2 ), present on filter grains, could abiotically be responsible for As(III) oxidation in the top of a rapid sand filter. For this purpose As(III) oxidation with two MnO 2 containing powders was investigated in aerobic water containing manganese(II) (Mn(II)), iron(II) (Fe(II)) and/or iron(III) (Fe(III)). The first MnO 2 powder was a very pure - commercially available - natural MnO 2 powder. The second originated from a filter sand coating, produced over 22 years in a rapid filter during aeration and filtration. Jar test experiments showed that both powders oxidised As(III). However, when applying the MnO 2 in aerated, raw groundwater, As(III) removal was not enhanced compared to aeration alone. It was found that the presence of Fe(II)) and Mn(II) inhibited As(III) oxidation, as Fe(II) and Mn(II) adsorption and oxidation were preferred over As(III) on the MnO 2 surface (at pH 7). Therefore it is concluded that just because MnO 2 is present in a filter bed, it does not necessarily mean that MnO 2 will be available to oxidise As(III). However, unlike Fe(II), the addition of Fe(III) did not hinder As(III) oxidation on the MnO 2 surface; resulting in subsequent effective As(V) removal by the flocculating hydrous ferric oxides. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. On the Design of Oxide Films, Nanomaterials, and Heterostructures for Solar Water Oxidation Photoanodes

    Science.gov (United States)

    Kronawitter, Coleman Xaver

    Photoelectrochemistry and its associated technologies show unique potential to facilitate the large-scale production of solar fuels—those energy-rich chemicals obtained through conversion processes driven by solar energy, mimicking the photosynthetic process of green plants. The critical component of photoelectrochemical devices designed for this purpose is the semiconductor photoelectrode, which must be optically absorptive, chemically stable, and possess the required electronic band alignment with respect to the redox couple of the electrolyte to drive the relevant electrochemical reactions. After many decades of investigation, the primary technological obstacle remains the development of photoelectrode structures capable of efficient and stable conversion of light with visible frequencies, which is abundant in the solar spectrum. Metal oxides represent one of the few material classes that can be made photoactive and remain stable to perform the required functions. The unique range of functional properties of oxides, and especially the oxides of transition metals, relates to their associated diversity of cation oxidation states, cation electronic configurations, and crystal structures. In this dissertation, the use of metal oxide films, nanomaterials, and heterostructures in photoelectrodes enabling the solar-driven oxidation of water and generation of hydrogen fuel is examined. A range of transition- and post-transition-metal oxide material systems and nanoscale architectures is presented. The first chapters present results related to electrodes based on alpha-phase iron(III) oxide, a promising visible-light-active material widely investigated for this application. Studies of porous films fabricated by physical vapor deposition reveal the importance of structural quality, as determined by the deposition substrate temperature, on photoelectrochemical performance. Heterostructures with nanoscale feature dimensionality are explored and reviewed in a later chapter

  13. Removal of NOM-constituents as characterized by LC-OCD and F-EEM during drinking water treatment

    KAUST Repository

    Baghoth, S. A.; Sharma, Saroj K.; Guitard, Marjorie; Heim, Vé ronique; Croue, Jean-Philippe; Amy, Gary L.

    2011-01-01

    Natural organic matter (NOM) is of concern in drinking water because it causes adverse aesthetic qualities such as taste, odour, and colour; impedes the performance of treatment processes; and decreases the effectiveness of oxidants

  14. Evacuation of performance and significant chemical constituents and by products in drinking water treatment

    International Nuclear Information System (INIS)

    Jamrah, I. A.

    1999-01-01

    Drinking water treatment is a task that comprises of several processes that eventually lead to the addition of chemicals to achieve the objectives of treatment. This study was conducted to assess treatment performance, explain the presence of significant chemical species in water, and investigate the interactions and chemical by-products that are formed during the course of treatment. Grab water samples were collected on a regular basis from the influent and effluent of Zai water treatment plant. Chemical analysis were conducted to determine the concentrations of various chemical species of interest. Turbidity, temperature, and pH of the samples were also measured. The study concluded that Zai Water Treatment Plant produces potable drinking water in accordance with Jordanian Standards. The use of treatment chemical resulted in an increase in the concentrations of certain materials, such as manganese, aluminum, and sulfate. The turbidity of the raw water and the TOC of the samples were positively correlated, and the treatment results in approximately 20% TOC reduction, which demonstrates that the measures used for the control of TOC (carbon adsorption and permanganate pre-oxidation), are not very effective. The study also showed that the TOC content of our raw water samples and the concentration of tribalomethanes resulting after disinfection were positively correlated, and that bromoform was the dominant component. Also chloroform was the minor component of tribalomethanes formed during treatment. Positive correlation between the total concentration of tribalomethanes in water and the chlorine dose used for disinfection was also observed, and the total concentration of tribalomethanes increased with temperature. The formation of tribalomethanes was enhanced as the pH of water increased and as the concentration of bromide ion in raw water became significant. (author). 25 refs., 14 figs.1 table

  15. Moderate KMnO4-Fe(II) pre-oxidation for alleviating ultrafiltration membrane fouling by algae during drinking water treatment.

    Science.gov (United States)

    Ma, Baiwen; Qi, Jing; Wang, Xing; Ma, Min; Miao, Shiyu; Li, Wenjiang; Liu, Ruiping; Liu, Huijuan; Qu, Jiuhui

    2018-05-21

    Although ultrafiltration (UF) membranes are highly beneficial for removing algae, the removal process causes serious UF membrane fouling. To avoid the unfavorable effects of algal cells that have been damaged by oxidants, our previous study reported a novel, moderate pre-oxidation method (KMnO 4 -Fe(II) process) that aimed to achieve a balance between the release of intracellular organic matter and enhanced algae removal. This study further investigated the performance of a UF membrane with KMnO 4 -Fe(II) pretreatment in the presence of algae-laden reservoir water after a long running time. We found that algae could be completely removed, membrane fouling was significantly alleviated, and the overall performance was much better than that of Fe(III) coagulation alone. The transmembrane pressure (TMP) during Fe(III) coagulation increased to 42.8 kPa, however, that of the KMnO 4 -Fe(II) process only increased to 25.1 kPa for after running for 90 d. The slower transmembrane pressure was attributed to the larger floc size, higher surface activity, and inactivation of algae. Although there was little effect on microorganism development, lower microorganism abundance (20.7%) was observed during the KMnO 4 -Fe(II) process than during coagulation alone (44.9%) due to the release of extracellular polymeric substances. We also found that the floc cake layer was easily removed by washing, and many of the original membrane pores were clearly observed. Further analysis demonstrated that the effluent quality was excellent, especially its turbidity, chromaticity, and Mn and Fe concentrations. Based on the outstanding UF membrane performance, it may be concluded that the KMnO 4 -Fe(II) process exhibits considerable potential for application in the treatment of algae-laden water. Copyright © 2018. Published by Elsevier Ltd.

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

    Energy Technology Data Exchange (ETDEWEB)

    Korolkov, Ilya V.; Mashentseva, Anastassiya A. [Institute of Nuclear Physics, Ibrahimov Str., 1, 050032 Almaty (Kazakhstan); The L.N. Gumilyov Eurasian National University, Satpaev Str., 5, 010008 Astana (Kazakhstan); Güven, Olgun [Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara (Turkey); Zdorovets, Maxim V. [Institute of Nuclear Physics, Ibrahimov Str., 1, 050032 Almaty (Kazakhstan); The L.N. Gumilyov Eurasian National University, Satpaev Str., 5, 010008 Astana (Kazakhstan); Taltenov, Abzal A. [The L.N. Gumilyov Eurasian National University, Satpaev Str., 5, 010008 Astana (Kazakhstan)

    2015-12-15

    In this study we present results on the application of advanced oxidation systems for effective and non-toxic oxidation of poly(ethylene terephthalate) track-etched membranes (PET TeMs) to improve their wettability and water transport properties. Two oxidizing systems: H{sub 2}O{sub 2} under UV irradiation (H{sub 2}O{sub 2}/UV) and Fenton system under visible light (Fenton/H{sub 2}O{sub 2}/Vis) were compared. The surface of functionalized PET TeMs was characterized by using colorimetric assay, contact angle measurements and X-ray photoelectron spectroscopy (XPS). Results clearly showed that water permeability of PET TeMs treated with H{sub 2}O{sub 2}/UV was improved by 28 ± 5% compared with etched-only membrane, the same parameter was found to increase by 13 ± 4% in the case of Fenton/H{sub 2}O{sub 2}/Vis treatment. The proposed oxidation technique is very simple, environment friendly and not requiring special equipment or expensive chemicals. The surface hydrophilicity of the membranes stored for 360 days in air between paper sheets was analyzed by contact angle test, colorimetric assay to measure concentration of carboxylic groups on the surface with toluidine blue and XPS analysis. The hydrophilic properties of oxidized PET TeMs were found to be stable for a long period of time.

  17. Reactions of ferrate(VI) with iodide and hypoiodous acid: kinetics, pathways, and implications for the fate of iodine during water treatment.

    Science.gov (United States)

    Shin, Jaedon; von Gunten, Urs; Reckhow, David A; Allard, Sebastien; Lee, Yunho

    2018-06-01

    Oxidative treatment of iodide-containing waters can form iodinated disinfection by-products (I-DBPs) that are more toxic than the regulated DBPs. To better understand the fate of iodine during water treatment with ferrate(VI), kinetics, products, and stoichiometries for the reactions of ferrate(VI) with iodide (I - ) and hypoiodous acid (HOI) were determined. Ferrate(VI) showed considerable reactivities to both I - and HOI with higher reactivities at lower pH. Interestingly, the reaction of ferrate(VI) with HOI ( k = 6.0×10 3 M -1 s -1 at pH 9) was much faster than with I - ( k = 5.6×10 M -1 s -1 at pH 9). The main reaction pathway during treatment of I - -containing waters was the oxidation of I - to HOI and its further oxidation to IO 3 - by ferrate(VI). However, for pH > 9, the HOI disproportionation catalyzed by ferrate(VI) became an additional transformation pathway forming I - and IO 3 - . The reduction of HOI by hydrogen peroxide ( k = 2.0×10 8 M -1 s -1 for the reaction, HOI + HO 2 - → I - + O 2 + 2H + ), the latter being produced from ferrate(VI) decomposition, also contributes to the I - regeneration in the pH range 9 - 11. A kinetic model was developed that could well simulate the fate of iodine in the ferrate(VI)-I - system. Overall, due to a rapid oxidation of I - to IO 3 - with short-lifetimes of HOI, ferrate(VI) oxidation appears to be a promising option for I-DBP mitigation during treatment of I - -containing waters.

  18. The use of Powdered Activated Carbon in reducing the Doc in water treatment plants

    International Nuclear Information System (INIS)

    Nikravesh, S. H.; Etemad-Shahidi, A.; Razeghi, N.

    2003-01-01

    Today as the technology improves and the application of energy and chemicals enhances, the organic pollutants increases in surface waters in which waste waters are discharged into. In order to reduce water-born diseases, necessary actions should be taken to decrease the pollutants. Common methods of surface water treatment are not sufficient anymore. Therefore complementary methods like using activated carbon, aeration, oxidation and reverse osmosis should be used. In this paper the use of powdered activated carbon, Total organic carbon test and jar test in reducing the concentration of organic carbons in water treatment is investigated. Initial experimental results showed large errors in total organic carbon evaluation so dissolved organic carbon was measured instead. The results showed that using the powdered activated carbon in addition to conventional treatment method using ferric chloride, greatly reduces organic pollutants. Adding about 60 mg/lit of powdered activated carbon may reduce dissolved organic carbon up to 90% in optimum conditions. However, different factors like the quality of surface water, experimental errors, instrumental errors and tool errors can influence the experimental results

  19. Behaviour and fate of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in drinking water treatment: a review.

    Science.gov (United States)

    Rahman, Mohammad Feisal; Peldszus, Sigrid; Anderson, William B

    2014-03-01

    This article reviews perfluoroalkyl and polyfluoroalkyl substance (PFAS) characteristics, their occurrence in surface water, and their fate in drinking water treatment processes. PFASs have been detected globally in the aquatic environment including drinking water at trace concentrations and due, in part, to their persistence in human tissue some are being investigated for regulation. They are aliphatic compounds containing saturated carbon-fluorine bonds and are resistant to chemical, physical, and biological degradation. Functional groups, carbon chain length, and hydrophilicity/hydrophobicity are some of the important structural properties of PFASs that affect their fate during drinking water treatment. Full-scale drinking water treatment plant occurrence data indicate that PFASs, if present in raw water, are not substantially removed by most drinking water treatment processes including coagulation, flocculation, sedimentation, filtration, biofiltration, oxidation (chlorination, ozonation, AOPs), UV irradiation, and low pressure membranes. Early observations suggest that activated carbon adsorption, ion exchange, and high pressure membrane filtration may be effective in controlling these contaminants. However, branched isomers and the increasingly used shorter chain PFAS replacement products may be problematic as it pertains to the accurate assessment of PFAS behaviour through drinking water treatment processes since only limited information is available for these PFASs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Bacterial Oxidation and Reduction of Iron in the Processes of Creation and Treatment of Acid Mining Waters

    Directory of Open Access Journals (Sweden)

    Daniel Kupka

    2004-12-01

    Full Text Available Acid mine drainages (AMDs arise at the weathering of sulphidic minerals. The occurrence of acidic streams is commonly associated with the human mining activities. Due to the disruption and excavation of sulphide deposits, the oxidation processes have initiated. Acidic products of sulphide oxidation accelerate the degradation of accompanying minerals. AMDs typically contain high concentrations of sulfuric acid and soluble metals and cause serious ecological problems due to the water pollution and the devastation of adjacent country. Microbial life in these extremely acidic environments may be considerably diverse. AMDs are abundant in bacteria capable to oxidize and/or to reduce iron. The rate of bacterial oxidation of ferrous iron released from pyrite surfaces is up to one million times faster than the chemical oxidation rate at low pH. Bacterial regeneration of ferric iron maintains the continuity of pyrite oxidation and the production of AMDs. Another group of microorganisms living in these environments are acidophilic ferric iron reducing bacteria. This group of microorganisms has been discovered only relatively recently. Acidophilic heterotrophic bacteria reduce ferric iron in either soluble or solid forms to ferrous iron. The reductive dissolution of ferric iron minerals brings about a mobilization of iron as well as associated heavy metals. The Bacterial oxidation and reduction of iron play an important role in the transformation of either crystalline or amorphous iron-containing minerals, including sulphides, oxides, hydroxysulfates, carbonates and silicates. This work discusses the role of acidophilic bacteria in the natural iron cycling and the genesis of acidic effluents. The possibilities of application of iron bacteria in the remediation of AMDs are also considered.

  1. Emissions from Produced Water Treatment Ponds, Uintah Basin, Utah, USA

    Science.gov (United States)

    Mansfield, M. L.; Lyman, S. N.; Tran, H.; O'Neil, T.; Anderson, R.

    2015-12-01

    An aqueous phase, known as "produced water," usually accompanies the hydrocarbon fluid phases that are extracted from Earth's crust during oil and natural gas extraction. Produced water contains dissolved and suspended organics and other contaminants and hence cannot be discharged directly into the hydrosphere. One common disposal method is to discharge produced water into open-pit evaporation ponds. Spent hydraulic fracturing fluids are also often discharged into the same ponds. It is obvious to anyone with a healthy olfactory system that such ponds emit volatile organics to the atmosphere, but very little work has been done to characterize such emissions. Because oil, gas, and water phases are often in contact in geologic formations, we can expect that more highly soluble compounds (e.g., salts, alcohols, carbonyls, carboxyls, BTEX, etc.) partition preferentially into produced water. However, as the water in the ponds age, many physical, chemical, and biological processes alter the composition of the water, and therefore the composition and strength of volatile organic emissions. For example, some ponds are aerated to hasten evaporation, which also promotes oxidation of organics dissolved in the water. Some ponds are treated with microbes to promote bio-oxidation. In other words, emissions from ponds are expected to be a complex function of the composition of the water as it first enters the pond, and also of the age of the water and of its treatment history. We have conducted many measurements of emissions from produced water ponds in the Uintah Basin of eastern Utah, both by flux chamber and by evacuated canister sampling with inverse modeling. These measurements include fluxes of CO2, CH4, methanol, and many other volatile organic gases. We have also measured chemical compositions and microbial content of water in the ponds. Results of these measurements will be reported.

  2. Removal of natural organic matter in drinking water treatment by coagulation: A comprehensive review.

    Science.gov (United States)

    Sillanpää, Mika; Ncibi, Mohamed Chaker; Matilainen, Anu; Vepsäläinen, Mikko

    2018-01-01

    Natural organic matter (NOM) is a complex matrix of organic substances produced in (or channeled to) aquatic ecosystems via various biological, geological and hydrological cycles. Such variability is posing a serious challenge to most water treatment technologies, especially the ones designed to treat drinking water supplies. Lately, in addition to the fluctuating composition of NOM, a substantial increase of its concentration in fresh waters, and also municipal wastewater effluents, has been reported worldwide, which justifies the urgent need to develop highly efficient and versatile water treatment processes. Coagulation is among the most applied processes for water and wastewater treatment. The application of coagulation to remove NOM from drinking water supplies has received a great deal of attention from researchers around the world because it was efficient and helped avoiding the formation of disinfection by products (DBPs). Nonetheless, with the increased fluctuation of NOM in water (concentration and composition), the efficiency of conventional coagulation was substantially reduced, hence the need to develop enhanced coagulation processes by optimizing the operating conditions (mainly the amount coagulants and pH), developing more efficient inorganic or organic coagulants, as well as coupling coagulation with other water treatment technologies. In the present review, recent research studies dealing with the application of coagulation for NOM removal from drinking water supplies are presented and compared. In addition, integration schemes combining coagulation and other water treatment processes are presented, including membrane filtration, oxidation, adsorption and others processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Solar based water treatment technologies

    International Nuclear Information System (INIS)

    Ahmad, I.; Hyder, M.J.

    2000-01-01

    In developing countries, the quality of drinking water is so poor that reports of 80% diseases from water-related causes is no surprise (Tebbet, 90). Frequently, there are reports in press of outbreak of epidemics in cities due to the unhygienic drinking-water. The state of affairs in the rural areas can be well imagined, where majority of the people live with no piped water. This paper describes the solar-based methods of removing organic pollutants from waste-water (also called Advanced Oxidation Technologies) and solar desalination. Experimental results of a simple solar water-sterilization technique have been discussed, along with suggestions to enhance the performance of this technique. (author)

  4. Occurrence and behaviour of dissolved, nano-particulate and micro-particulate iron in waste waters and treatment systems: new insights from electrochemical analysis.

    Science.gov (United States)

    Matthies, R; Aplin, A C; Horrocks, B R; Mudashiru, L K

    2012-04-01

    Cyclic-, Differential Pulse- and Steady-state Microdisc Voltammetry (CV, DPV, SMV) techniques have been used to quantify the occurrence and fate of dissolved Fe(ii)/Fe(iii), nano-particulate and micro-particulate iron over a 12 month period in a series of net-acidic and net-alkaline coal mine drainages and passive treatment systems. Total iron in the mine waters is typically 10-100 mg L(-1), with values up to 2100 mg L(-1). Between 30 and 80% of the total iron occurs as solid phase, of which 20 to 80% is nano-particulate. Nano-particulate iron comprises 20 to 70% of the nominally "dissolved" (i.e. sedimentation are the only processes required to remove solid phase iron, these data have important implications for the generation or consumption of acidity during water treatment. In most waters, the majority of truly dissolved iron occurs as Fe(ii) (average 64 ± 22%). Activities of Fe(ii) do not correlate with pH and geochemical modelling shows that no Fe(ii) mineral is supersaturated. Removal of Fe(ii) must proceed via oxidation and hydrolysis. Except in waters with pH waters are generally supersaturated with respect to ferrihydrite and schwertmannite, and are not at redox equilibrium, indicating the key role of oxidation and hydrolysis kinetics on water treatment. Typically 70-100% of iron is retained in the treatment systems. Oxidation, hydrolysis, precipitation, coagulation and sedimentation occur in all treatment systems and - independent of water chemistry and the type of treatment system - hydroxides and oxyhydroxysulfates are the main iron sinks. The electrochemical data thus reveal the rationale for incomplete iron retention in individual systems and can thus inform future design criteria. The successful application of this low cost and rapid electrochemical method demonstrates its significant potential for real-time, on-site monitoring of iron-enriched waters and may in future substitute traditional analytical methods.

  5. Iron oxidation kinetics and phosphorus immobilization at the groundwater-surface water interface

    Science.gov (United States)

    van der Grift, Bas; Rozemeijer, Joachim; Griffioen, Jasper; van der Velde, Ype

    2014-05-01

    Eutrophication of freshwater environments following diffuse nutrient loads is a widely recognized water quality problem in catchments. Fluxes of non-point P sources to surface waters originate from surface runoff and flow from soil water and groundwater into surface water. The availability of P in surface waters is controlled strongly by biogeochemical nutrient cycling processes at the soil-water interface. The mechanisms and rates of the iron oxidation process with associated binding of phosphate during exfiltration of anaerobic Fe(II) bearing groundwater are among the key unknowns in P retention processes in surface waters in delta areas where the shallow groundwater is typically pH-neutral to slightly acid, anoxic, iron-rich. We developed an experimental field set-up to study the dynamics in Fe(II) oxidation and mechanisms of P immobilization at the groundwater-surface water interface in an agricultural experimental catchment of a small lowland river. We physically separated tube drain effluent from groundwater discharge before it entered a ditch in an agricultural field. The exfiltrating groundwater was captured in in-stream reservoirs constructed in the ditch. Through continuous discharge measurements and weekly water quality sampling of groundwater, tube drain water, exfiltrated groundwater, and ditch water, we quantified Fe(II) oxidation kinetics and P immobilization processes across the seasons. This study showed that seasonal changes in climatic conditions affect the Fe(II) oxidation process. In winter time the dissolved iron concentrations in the in-stream reservoirs reached the levels of the anaerobic groundwater. In summer time, the dissolved iron concentrations of the water in the reservoirs are low, indicating that dissolved Fe(II) is completely oxidized prior to inflow into the reservoirs. Higher discharges, lower temperatures and lower pH of the exfiltrated groundwater in winter compared to summer shifts the location of the redox transition zone

  6. Mine water treatment in Donbass

    Energy Technology Data Exchange (ETDEWEB)

    Azarenkov, P A; Anisimov, V M; Krol, V A

    1980-10-01

    About 2,000,000 m$SUP$3 of mine water are discharged by coal mines yearly to surface waters in the Donbass. Mine water in the region is rich in mineral salts and suspended matter (coal and rock particles). The DonUGI Institute developed a system of mine water treatment which permits the percentage of suspended matter to be reduced to 1.5 mg/l. The treated mine water can be used in fire fighting and in dust suppression systems in coal mines. A scheme of the water treatment system is shown. It consists of the following stages: reservoir of untreated mine water, chamber where mine water is mixed with reagents, primary sedimentation tanks, sand filters, and chlorination. Aluminium sulphate is used as a coagulation agent. To intensify coagulation polyacrylamide is added. Technical specifications of surface structures in which water treatment is carried out are discussed. Standardized mine water treatment systems with capacities of 600 m$SUP$3/h, with 900, 1200, 1500, 1800 and 2100 m$SUP$3/h capacities are used. (In Russian)

  7. Degradation of nicotine in water solutions using a water falling film DBD plasma reactor: direct and indirect treatment

    Science.gov (United States)

    Krupež, Jelena; Kovačević, Vesna V.; Jović, Milica; Roglić, Goran M.; Natić, Maja M.; Kuraica, Milorad M.; Obradović, Bratislav M.; Dojčinović, Biljana P.

    2018-05-01

    Nicotine degradation efficiency in water solutions was studied using a water falling film dielectric barrier discharge (DBD) reactor. Two different treatments were applied: direct treatment, the recirculation of the solution through a DBD reactor, and indirect treatment, the bubbling of the gas from the DBD through the porous filter into the solution. In a separate experiment, samples spiked with nicotine in double distilled water (ddH2O) and tap water were studied and compared after both treatments. Furthermore, the effects of the homogeneous catalysts, namely, Fe2+ and H2O2, were tested in the direct treatment. Nicotine degradation efficiency was determined using high-performance liquid chromatography. A degradation efficiency of 90% was achieved after the direct treatment catalyzed with Fe2+. In order to analyze the biodegradability, mineralization level, and toxicity of the obtained solutions, after all degradation procedures the values of the following parameters were determined: total organic carbon, chemical oxygen demand, biochemical oxygen demand, and the Artemia salina toxicity test. The results showed that an increase in biodegradability was obtained, after all treatments. A partial nicotine mineralization was achieved and the mortality of the A. salina organism decreased in the treated samples, all of which indicating the effective removal of nicotine and the creation of less toxic solutions. Nicotine degradation products were identified using ultrahigh-performance liquid chromatography coupled with a linear ion trap Orbitrap hybrid mass spectrometer and a simple mechanism for oxidative degradation of nicotine in non-thermal plasma systems is proposed.

  8. Novel approach to zinc removal from circum-neutral mine waters using pelletised recovered hydrous ferric oxide.

    Science.gov (United States)

    Mayes, William M; Potter, Hugh A B; Jarvis, Adam P

    2009-02-15

    Data are presented which evaluate the performance of a pilot-scale treatment system using pelletised hydrous ferric oxide (HFO; a waste stream from coal mine water treatment) as a high surface area sorbent for removing zinc (Zn) from a metal mine water discharge in the North Pennines Orefield, UK. Over a 10-month period the system removed Zn at mean area- and volume-adjusted removal rates of 3.7 and 8.1gm(-3)day(-1), respectively, with a mean treatment efficiency of 32% at a low mean residence time of 49min. There were seasonal effects in Zn removal owing to establishment and dieback of algae in the treatment tank. This led to increased Zn uptake in early summer months followed by slight Zn release upon algae senescence. In addition to these biosorptive processes, the principal sinks for Zn appear to be (1) sorption onto the HFO surface, and (2) precipitation with calcite-dominated secondary minerals. The latter were formed as a product of dissolution of portlandite in the cement binder and calcium recarbonation. Further optimisation of the HFO pelletisation process holds the possibility for providing a low-cost, low footprint treatment option for metal rich mine waters, in addition to a valuable after-use for recovered HFO from coal mine water treatment facilities.

  9. Cholesterol Protects the Oxidized Lipid Bilayer from Water Injury

    DEFF Research Database (Denmark)

    Owen, Michael C; Kulig, Waldemar; Rog, Tomasz

    2018-01-01

    In an effort to delineate how cholesterol protects membrane structure under oxidative stress conditions, we monitored the changes to the structure of lipid bilayers comprising 30 mol% cholesterol and an increasing concentration of Class B oxidized 1-palmitoyl-2-oleoylphosphatidylcholine (POPC...... in a characteristic reduction in bilayer thickness and increase in area per lipid, thereby increasing the exposure of the membrane hydrophobic region to water. However, cholesterol was observed to help reduce water injury by moving into the bilayer core and forming more hydrogen bonds with the oxPLs. Cholesterol also...... resists altering its tilt angle, helping to maintain membrane integrity. Water that enters the 1-nm-thick core region remains part of the bulk water on either side of the bilayer, with relatively few water molecules able to traverse through the bilayer. In cholesterol-rich membranes, the bilayer does...

  10. Isotopic Studies of O-O Bond Formation During Water Oxidation (SISGR)

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Justine P. [Johns Hopkins Univ., Baltimore, MD (United States)

    2015-03-03

    Isotopic Studies of O-O Bond Formation During Water Oxidation (SISGR) Research during the project period focused primarily on mechanisms of water oxidation by structurally defined transition metal complexes. Competitive oxygen isotope fractionation of water, mediated by oxidized precursors or reduced catalysts together with ceric, Ce(IV), ammonium nitrate in aqueous media, afforded oxygen-18 kinetic isotope effects (O-18 KIEs). Measurement, calculation, and interpretation of O-18 KIEs, described in the accompanying report has important ramifications for the production of electricity and solar hydrogen (as fuel). The catalysis division of BES has acknowledged that understanding mechanisms of transition metal catalyzed water oxidation has major ramifications, potentially leading to transformation of the global economy and natural environment in years to come. Yet, because of program restructuring and decreased availability of funds, it was recommended that the Solar Photochemistry sub-division of BES would be a more appropriate parent program for support of continued research.

  11. Experimental investigation on the combined use of C1O2 and NaC1O for drinking water treatment

    International Nuclear Information System (INIS)

    Sani, B.; Rossi, L.; Santianni, D.; Anichini, B.; Caretti, C.; Lubello, C.

    2005-01-01

    In Italy, most of the plants producing water for human consumption, use Chlorine Dioxide (C1O 2 ) and Sodium Hypochlorite (NaC1O) for the oxidation and disinfection treatments. These chemical disinfectants, which are very effective as regards the oxidation power, the disinfection capability and the bacteriostatic action, produce by-products harmful for human health: Chlorite and Trihalomethanes (THMs) respectively. The Italian Regulations (D.Lgs. 31/2001) sets very restrictive limits for the maximum concentration of these by-products in drinking water. Moreover, from December 2006, the limit for chlorite will be even more restrictive and, with present treatment process, the compliance with the regulation will be very difficult. Therefore the experimentation of alternative treatment techniques and products is of great interest. This article presents an experimental investigation on the combined use of C1O 2 and NaC1O in the treatment of final water from two different plants producing drinking water in Florence. The main objective of this investigation was to evaluate the use of these two products in combination so as to keep the advantages (disinfection efficiency and stability in water) and to minimize the disadvantages (by-products formation) present when using this products separately. Positive results achieved in the experimental phase were used to evaluate the possible applications on real drinking water treatment conditions [it

  12. Electrochemical Water-Splitting Based on Hypochlorite Oxidation

    Czech Academy of Sciences Publication Activity Database

    Minhová Macounová, Kateřina; Simic, N.; Ahlberg, E.; Krtil, Petr

    2015-01-01

    Roč. 137, č. 23 (2015), s. 7262-7265 ISSN 0002-7863 Institutional support: RVO:61388955 Keywords : electrochemistry * hypochlorite oxidation * water-splitting Subject RIV: CG - Electrochemistry Impact factor: 13.038, year: 2015

  13. Synthesis of superconducting cobalt oxyhydrates using a novel method: Electrolyzed and oxidized water

    International Nuclear Information System (INIS)

    Liu, C.-J.; Wu, T.-H.; Hsu, L.-L.; Wang, J.-S.; Chen, S.-Y.

    2007-01-01

    By deintercalation of Na + followed by inserting bilayers of water molecules into the host lattice, the layered cobalt oxide of γ-Na 0.7 CoO 2 undergoes a topotactic transformation to a layered cobalt oxyhydrate of Na 0.35 (H 2 O) 1.3 CoO 2-δ with the c-axis expanded from c ∼ 10.9 A to c ∼ 19.6 A. In this paper, we demonstrate that the superconducting phase of c ∼ 19.6 A can be directly obtained by simply immersing γ-Na 0.7 CoO 2 powders in electrolyzed/oxidized (EO) water, which is readily available from a commercial electrolyzed water generator. We found that high oxidation-reduction potential of EO water drives the oxidation of the cobalt ions accompanying by the formation of the superconductive c ∼ 19.6 A phase. Our results demonstrate how EO water can be used to oxidize the cobalt ions and hence form superconducting cobalt oxyhydrates in a clean and simple way and may provide an economic and environment-friendly route to oxidize the transition metal of complex metal oxides

  14. Synthesis of superconducting cobalt oxyhydrates using a novel method: Electrolyzed and oxidized water

    Science.gov (United States)

    Liu, Chia-Jyi; Wu, Tsung-Hsien; Hsu, Lin-Li; Wang, Jung-Sheng; Chen, Shu-Yo

    2007-09-01

    By deintercalation of Na+ followed by inserting bilayers of water molecules into the host lattice, the layered cobalt oxide of γ-Na0.7CoO2 undergoes a topotactic transformation to a layered cobalt oxyhydrate of Na0.35(H2O)1.3CoO2-δ with the c-axis expanded from c ≈ 10.9 Å to c ≈ 19.6 Å. In this paper, we demonstrate that the superconducting phase of c ≈ 19.6 Å can be directly obtained by simply immersing γ-Na0.7CoO2 powders in electrolyzed/oxidized (EO) water, which is readily available from a commercial electrolyzed water generator. We found that high oxidation-reduction potential of EO water drives the oxidation of the cobalt ions accompanying by the formation of the superconductive c ≈ 19.6 Å phase. Our results demonstrate how EO water can be used to oxidize the cobalt ions and hence form superconducting cobalt oxyhydrates in a clean and simple way and may provide an economic and environment-friendly route to oxidize the transition metal of complex metal oxides.

  15. Synthesis of superconducting cobalt oxyhydrates using a novel method: Electrolyzed and oxidized water

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.-J. [Department of Physics, National Changhua University of Education, Changhua 50007, Taiwan (China)], E-mail: liucj@cc.ncue.edu.tw; Wu, T.-H.; Hsu, L.-L.; Wang, J.-S.; Chen, S.-Y. [Department of Physics, National Changhua University of Education, Changhua 50007, Taiwan (China)

    2007-09-01

    By deintercalation of Na{sup +} followed by inserting bilayers of water molecules into the host lattice, the layered cobalt oxide of {gamma}-Na{sub 0.7}CoO{sub 2} undergoes a topotactic transformation to a layered cobalt oxyhydrate of Na{sub 0.35}(H{sub 2}O){sub 1.3}CoO{sub 2-{delta}} with the c-axis expanded from c {approx} 10.9 A to c {approx} 19.6 A. In this paper, we demonstrate that the superconducting phase of c {approx} 19.6 A can be directly obtained by simply immersing {gamma}-Na{sub 0.7}CoO{sub 2} powders in electrolyzed/oxidized (EO) water, which is readily available from a commercial electrolyzed water generator. We found that high oxidation-reduction potential of EO water drives the oxidation of the cobalt ions accompanying by the formation of the superconductive c {approx} 19.6 A phase. Our results demonstrate how EO water can be used to oxidize the cobalt ions and hence form superconducting cobalt oxyhydrates in a clean and simple way and may provide an economic and environment-friendly route to oxidize the transition metal of complex metal oxides.

  16. Experimental Study on Treatment of Dyeing Wastewater by Activated Carbon Adsorption, Coagulation and Fenton Oxidation

    Science.gov (United States)

    Xiaoxu, SUN; Jin, XU; Xingyu, LI

    2017-12-01

    In this paper dyeing waste water was simulated by reactive brilliant blue XBR, activated carbon adsorption process, coagulation process and chemical oxidation process were used to treat dyeing waste water. In activated carbon adsorption process and coagulation process, the water absorbance values were measured. The CODcr value of water was determined in Fenton chemical oxidation process. Then, the decolorization rate and COD removal rate were calculated respectively. The results showed that the optimum conditions of activated carbon adsorption process were as follows: pH=2, the dosage of activated carbon was 1.2g/L, the adsorption reaction time was 60 min, and the average decolorization rate of the three parallel experiments was 85.30%. The optimum conditions of coagulation experiment were as follows: pH=8~9, PAC dosage was 70mg/L, stirring time was 20min, standing time was 45min, the average decolorization rate of the three parallel experiments was 74.48%. The optimum conditions for Fenton oxidation were Fe2+ 0.05g/L, H2O2 (30%) 14mL/L, pH=3, reaction time 40min. The average CODcr removal rate was 69.35% in three parallel experiments. It can be seen that in the three methods the activated carbon adsorption treatment of dyeing wastewater was the best one.

  17. Toxicological and chemical assessment of arsenic-contaminated groundwater after electrochemical and advanced oxidation treatments.

    Science.gov (United States)

    Radić, Sandra; Crnojević, Helena; Vujčić, Valerija; Gajski, Goran; Gerić, Marko; Cvetković, Želimira; Petra, Cvjetko; Garaj-Vrhovac, Vera; Oreščanin, Višnja

    2016-02-01

    Owing to its proven toxicity and mutagenicity, arsenic is regarded a principal pollutant in water used for drinking. The objective of this study was the toxicological and chemical evaluation of groundwater samples obtained from arsenic enriched drinking water wells before and after electrochemical and ozone-UV-H2O2-based advanced oxidation processes (EAOP). For this purpose, acute toxicity test with Daphnia magna and chronic toxicity test with Lemna minor L. were employed as well as in vitro bioassays using human peripheral blood lymphocytes (HPBLs). Several oxidative stress parameters were estimated in L.minor. Physicochemical analysis showed that EAOP treatment was highly efficient in arsenic but also in ammonia and organic compound removal from contaminated groundwater. Untreated groundwater caused only slight toxicity to HPBLs and D. magna in acute experiments. However, 7-day exposure of L. minor to raw groundwater elicited genotoxicity, a significant growth inhibition and oxidative stress injury. The observed genotoxicity and toxicity of raw groundwater samples was almost completely eliminated by EAOP treatment. Generally, the results obtained with L. minor were in agreement with those obtained in the chemical analysis suggesting the sensitivity of the model organism in monitoring of arsenic-contaminated groundwater. In parallel to chemical analysis, the implementation of chronic toxicity bioassays in a battery is recommended in the assessment of the toxic and genotoxic potential of such complex mixtures. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Methane oxidation and methane fluxes in the ocean surface layer and deep anoxic waters

    Science.gov (United States)

    Ward, B. B.; Kilpatrick, K. A.; Novelli, P. C.; Scranton, M. I.

    1987-01-01

    Measured biological oxidation rates of methane in near-surface waters of the Cariaco Basin are compared with the diffusional fluxes computed from concentration gradients of methane in the surface layer. Methane fluxes and oxidation rates were investigated in surface waters, at the oxic/anoxic interface, and in deep anoxic waters. It is shown that the surface-waters oxidation of methane is a mechanism which modulates the flux of methane from marine waters to the atmosphere.

  19. Organic micropollutants (OMPs) in natural waters: Oxidation by UV/H2O2 treatment and toxicity assessment.

    Science.gov (United States)

    Rozas, Oscar; Vidal, Cristiane; Baeza, Carolina; Jardim, Wilson F; Rossner, Alfred; Mansilla, Héctor D

    2016-07-01

    Organic micropollutants (OMPs) are ubiquitous in natural waters even in places where the human activity is limited. The presence of OMPs in natural water sources for human consumption encourages the evaluation of different water purification technologies to ensure water quality. In this study, the Biobío river (Chile) was selected since the watershed includes urban settlements and economic activities (i.e. agriculture, forestry) that incorporate a variety of OMPs into the aquatic environment, such as pesticides, pharmaceuticals and personal care products. Atrazine (herbicide), caffeine (psychotropic), diclofenac (anti-inflammatory) and triclosan (antimicrobial) in Biobío river water and in different stages of a drinking and two wastewater treatment plants downstream Biobío river were determined using solid phase extraction (SPE) and liquid chromatography/tandem mass spectrometry (LC-MS/MS) and electrospray ionization (ESI). Quantification of these four compounds showed concentrations in the range of 8 ± 2 to 55 ± 10 ng L(-1) in Biobío river water, 11 ± 2 to 74 ± 21 ng L(-1) in the drinking water treatment plant, and 60 ± 10 to 15,000 ± 1300 ng L(-1) in the wastewater treatment plants. Caffeine was used as an indicator of wastewater discharges. Because conventional water treatment technologies are not designed to eliminate some emerging organic pollutants, alternative treatment processes, UV and UV/H2O2, were employed. The transformation of atrazine, carbamazepine (antiepileptic), diclofenac and triclosan was investigated at laboratory scale. Both processes were tested at different UV doses and the Biobío river water matrix effects were evaluated. Initial H2O2 concentration used was 10 mg L(-1). Results showed that, the transformation profile obtained using UV/H2O2 at UV doses up to 900 mJ cm(-2), followed the trend of diclofenac > triclosan > atrazine > carbamazepine. Furthermore acute toxicity tests with Daphnia magna were carried

  20. Recovery of copper and lead from waste printed circuit boards by supercritical water oxidation combined with electrokinetic process

    International Nuclear Information System (INIS)

    Xiu Furong; Zhang Fushen

    2009-01-01

    An effective and benign process for copper and lead recovery from waste printed circuit boards (PCBs) was developed. In the process, the PCBs was pre-treated in supercritical water, then subjected to electrokinetic (EK) process. Experimental results showed that supercritical water oxidation (SCWO) process was strong enough to decompose the organic compounds of PCBs, and XRD spectra indicated that copper and lead were oxidized into CuO, Cu 2 O and β-PbO 2 in the process. The optimum SCWO treatment conditions were 60 min, 713 K, 30 MPa, and EK treatment time, constant current density were 11 h, 20 mA cm -2 , respectively. The recovery percentages of copper and lead under optimum SCWO + EK treatment conditions were around 84.2% and 89.4%, respectively. In the optimized EK treatment, 74% of Cu was recovered as a deposit on the cathode with a purity of 97.6%, while Pb was recovered as concentrated solutions in either anode (23.1%) or cathode (66.3%) compartments but little was deposited on the electrodes. It is believed that the process is effective and practical for Cu and Pb recovery from waste electric and electronic equipments.

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

    Science.gov (United States)

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

    2015-03-24

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

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

    KAUST Repository

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

    2015-01-01

    Reactively sputtered nickel oxide (NiOx) films provide transparent, antireflective, electrically conductive, chemically stable coatings that also are highly active electrocatalysts for the oxidation of water to O2(g). These NiOx coatings provide

  3. In-situ treatment of acid mine waters using fluidized bed ash: Field study

    International Nuclear Information System (INIS)

    Everett, J.W.; Canty, G.A.

    1999-01-01

    A slurry of mine water and fluidized bed ash (FBA) was injected into an abandoned coal mine in eastern Oklahoma in July 1997. Oil-field technology was used to inject 1.8 Gg (418 tons) of FBA through five wells in 15 hours. Prior to injection the seep water had a pH of 4.4, was net acidic (acidity over 400 mg/L as CaCO 3 ), and had relatively high metal concentrations (in mg/L: Fe-200; Mn-7; and Al-6). After injection, during the period of effective treatment, the seep water had a pH above 6.0, less net acidity, and had lower metals concentrations (in mg/L: Fe-120; Mn-5; and Al-< PQL). When the treated seep water exited the mine, the dissolved metals oxidized and hydrolyzed. As the metals precipitated, the alkalinity introduced by the FBA was consumed and the pH dropped. However, the seep water characteristics upon entering the receiving stream were improved, compared to pre-injection. The resulting seep water quality is such that it is more amenable to further treatment by passive treatment methods, such as anoxic limestone drains or wetlands. Alkaline injection is a finite treatment process. Eventually, the added alkalinity is exhausted, at which time the seep returns to pre-injection conditions, necessitating another injection of ash. For the study discussed in this paper, the treatment lasted approximately 15 months. While the amount of alkalinity added to the mine could have potentially treated much more than a year's volume of seep water, it is believed that much of the injected alkalinity was unavailable in backwater areas in the mine. This alkalinity contributed little, if any, to the treatment of water flowing through the mine. Mine hydrology, especially during injection are crucial to treatment longevity

  4. Oxidation behavior of steels and Alloy 800 in supercritical water

    International Nuclear Information System (INIS)

    Olmedo, A.M.; Bordoni, R.; Dominguez, G.; Alvarez, M.G.

    2011-01-01

    The oxidation behavior of a ferritic-martensitic steel T91 and a martensitic steel AISI 403 up to 750 h, and of AISI 316L and Alloy 800 up to 336 h in deaerated supercritical water, 450ºC-25 MPa, was investigated in this paper. After exposure up to 750 h, the weight gain data, for steels T91 and AISI 403, was fitted by ∆W=k t n , were n are similar for both steels and k is a little higher for T91. The oxide films grown in the steels were characterized using gravimetry, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and X-ray diffraction. The films were adherent and exhibited a low porosity. For this low oxygen content supercritical water exposure, the oxide scale exhibited a typical duplex structure, in which the scale is composed of an outer iron oxide layer of magnetite (Fe 3 O 4 ) and an inner iron/chromium oxide layer of a non-stoichiometric iron chromite (Fe,Cr) 3 O 4 . Preliminary results, with AISI 316L and Alloy 800, for two exposure periods (168 and 336 h), are also reported. The morphology shown for the oxide films grown on both materials up to 336 h of oxidation in supercritical water, resembles that of a duplex layer film like that shown by stainless steels and Alloy 800 oxide films grown in a in a high temperature and pressure (220-350ºC) of a primary or secondary coolant of a plant. (author) [es

  5. Electrochemical Water Oxidation by a Catalyst-Modified Metal-Organic Framework Thin Film

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Shaoyang; Pineda-Galvan, Yuliana; Maza, William A.; Epley, Charity C.; Zhu, Jie; Kessinger, Matthew C.; Pushkar, Yulia; Morris, Amanda J. (VP); (Purdue)

    2016-12-15

    Water oxidation, a key component in artificial photosynthesis, requires high overpotentials and exhibits slow reaction kinetics that necessitates the use of stable and efficient heterogeneous water-oxidation catalysts (WOCs). Here, we report the synthesis of UiO-67 metal–organic framework (MOF) thin films doped with [Ru(tpy)(dcbpy)OH2]2+ (tpy=2,2':6',2''-terpyridine, dcbpy=5,5'-dicarboxy-2,2'-bipyridine) on conducting surfaces and their propensity for electrochemical water oxidation. The electrocatalyst oxidized water with a turnover frequency (TOF) of (0.2±0.1) s-1 at 1.71 V versus the normal hydrogen electrode (NHE) in buffered solution (pH~7) and exhibited structural and electrochemical stability. The electroactive sites were distributed throughout the MOF thin film on the basis of scan-ratedependent voltammetry studies. This work demonstrates a promising way to immobilize large concentrations of electroactive WOCs into a highly robust MOF scaffold and paves the way for future photoelectrochemical water-splitting systems.

  6. Simulation of uranium and plutonium oxides compounds obtained in plasma

    Science.gov (United States)

    Novoselov, Ivan Yu.; Karengin, Alexander G.; Babaev, Renat G.

    2018-03-01

    The aim of this paper is to carry out thermodynamic simulation of mixed plutonium and uranium oxides compounds obtained after plasma treatment of plutonium and uranium nitrates and to determine optimal water-salt-organic mixture composition as well as conditions for their plasma treatment (temperature, air mass fraction). Authors conclude that it needs to complete the treatment of nitric solutions in form of water-salt-organic mixtures to guarantee energy saving obtainment of oxide compounds for mixed-oxide fuel and explain the choice of chemical composition of water-salt-organic mixture. It has been confirmed that temperature of 1200 °C is optimal to practice the process. Authors have demonstrated that condensed products after plasma treatment of water-salt-organic mixture contains targeted products (uranium and plutonium oxides) and gaseous products are environmental friendly. In conclusion basic operational modes for practicing the process are showed.

  7. Impact of Oxidative Dissolution on Black Shale Fracturing: Implication for Shale Fracturing Treatment Design

    Science.gov (United States)

    You, L.; Chen, Q.; Kang, Y.; Cheng, Q.; Sheng, J.

    2017-12-01

    Black shales contain a large amount of environment-sensitive compositions, e.g., clay minerals, carbonate, siderite, pyrite, and organic matter. There have been numerous studies on the black shales compositional and pore structure changes caused by oxic environments. However, most of the studies did not focus on their ability to facilitate shale fracturing. To test the redox-sensitive aspects of shale fracturing and its potentially favorable effects on hydraulic fracturing in shale gas reservoirs, the induced microfractures of Longmaxi black shales exposed to deionized water, hydrochloric acid, and hydrogen peroxide at room-temperature for 240 hours were imaged by scanning electron microscopy (SEM) and CT-scanning in this paper. Mineral composition, acoustic emission, swelling, and zeta potential of the untreated and oxidative treatment shale samples were also recorded to decipher the coupled physical and chemical effects of oxidizing environments on shale fracturing processes. Results show that pervasive microfractures (Fig.1) with apertures ranging from tens of nanometers to tens of microns formed in response to oxidative dissolution by hydrogen peroxide, whereas no new microfracture was observed after the exposure to deionized water and hydrochloric acid. The trajectory of these oxidation-induced microfractures was controlled by the distribution of phyllosilicate framework and flaky or stringy organic matter in shale. The experiments reported in this paper indicate that black shales present the least resistance to crack initiation and subcritical slow propagation in hydrogen peroxide, a process we refer to as oxidation-sensitive fracturing, which are closely related to the expansive stress of clay minerals, dissolution of redox-sensitive compositions, destruction of phyllosilicate framework, and the much lower zeta potential of hydrogen peroxide solution-shale system. It could mean that the injection of fracturing water with strong oxidizing aqueous solution may

  8. Electrocatalytic Water Oxidation by a Homogeneous Copper Catalyst Disfavors Single-Site Mechanisms.

    Science.gov (United States)

    Koepke, Sara J; Light, Kenneth M; VanNatta, Peter E; Wiley, Keaton M; Kieber-Emmons, Matthew T

    2017-06-28

    Deployment of solar fuels derived from water requires robust oxygen-evolving catalysts made from earth abundant materials. Copper has recently received much attention in this regard. Mechanistic parallels between Cu and single-site Ru/Ir/Mn water oxidation catalysts, including intermediacy of terminal Cu oxo/oxyl species, are prevalent in the literature; however, intermediacy of late transition metal oxo species would be remarkable given the high d-electron count would fill antibonding orbitals, making these species high in energy. This may suggest alternate pathways are at work in copper-based water oxidation. This report characterizes a dinuclear copper water oxidation catalyst, {[(L)Cu(II)] 2 -(μ-OH) 2 }(OTf) 2 (L = Me 2 TMPA = bis((6-methyl-2-pyridyl)methyl)(2-pyridylmethyl)amine) in which water oxidation proceeds with high Faradaic efficiency (>90%) and moderate rates (33 s -1 at ∼1 V overpotential, pH 12.5). A large kinetic isotope effect (k H /k D = 20) suggests proton coupled electron transfer in the initial oxidation as the rate-determining step. This species partially dissociates in aqueous solution at pH 12.5 to generate a mononuclear {[(L)Cu(II)(OH)]} + adduct (K eq = 0.0041). Calculations that reproduce the experimental findings reveal that oxidation of either the mononuclear or dinuclear species results in a common dinuclear intermediate, {[LCu(III)] 2 -(μ-O) 2 } 2+ , which avoids formation of terminal Cu(IV)═O/Cu(III)-O • intermediates. Calculations further reveal that both intermolecular water nucleophilic attack and redox isomerization of {[LCu(III)] 2 -(μ-O) 2 } 2+ are energetically accessible pathways for O-O bond formation. The consequences of these findings are discussed in relation to differences in water oxidation pathways between Cu catalysts and catalysts based on Ru, Ir, and Mn.

  9. Effect of surface treatments on the bond strength between resin cement and differently sintered zirconium-oxide ceramics.

    Science.gov (United States)

    Yenisey, Murat; Dede, Doğu Ömür; Rona, Nergiz

    2016-01-01

    This study investigated the effects of surface treatments on bond strength between resin cement and differently sintered zirconium-oxide ceramics. 220 zirconium-oxide ceramic (Ceramill ZI) specimens were prepared, sintered in two different period (Short=Ss, Long=Ls) and divided into ten treatment groups as: GC, no treatment; GSil, silanized (ESPE-Sil); GSilPen, silane flame treatment (Silano-Pen); GSb, sandblasted; GSbSil, sandblasted+silanized; GSbCoSil, sandblasted+silica coated (CoJet)+silanized; GSbRoSil, sandblasted+silica coated (Rocatech-Plus)+silanized; GSbDSil, sandblasted+diamond particle abraded (Micron MDA)+silanized; GSbSilPen, sandblasted+silane flame treatment+silanized; GSbLSil, sandblasted+Er:Yag (Asclepion-MCL30) laser treated+silanized. The composite resin (Filtek Z-250) cylinders were cemented to the treated ceramic surfaces with a resin cement (Panavia F2.0). Shear bond strength test was performed after specimens were stored in water for 24h and thermo-cycled for 6000 cycles (5-55 °C). Data were statistically analyzed with two-way analysis of variance (ANOVA) and Tamhane's multiple comparison test (α=0.05). According to the ANOVA, sintering time, surface treatments and their interaction were statistically significant (pzirconium-oxide ceramics. Copyright © 2015 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  10. Treatment of high organic strength waste waters; Tratamiento de aguas residuales de alta carga

    Energy Technology Data Exchange (ETDEWEB)

    Marti Duran, J.; Leyda Escoruela, L. [COMSA, S.A., Madrid (Spain)

    1995-11-01

    A biological treatment process is likely to be the preferred and main stage for the treatment of high strength waste waters. In some instance the wastes will contain a fraction of toxic or non-biodegradable organic constituents which affects the implementation of the central biological process. Two different technologies using tower-shape reactors are described, together with a Low Pressure Chemical Oxidation process technology used in the pretreatment of poorly biodegradable wastes.

  11. Reduction of tri halomethanes in drinking water using chlorine dioxide as a pre oxidant; Rduccion de trihalometanos en agua potable mediante preoxidacion con dioxido de cloro

    Energy Technology Data Exchange (ETDEWEB)

    Marcian Cervera, V. J.; Monforte Monleon, L.; Ribera Orts, R.; Alvarez Alondiga, I.; Garcia Garrido, J.

    2007-07-01

    The object of the present study is to verify the suitability of using chlorine dioxide as a pre oxidant in the Water Treatment Plant of La Presa (Manises) and El Realon (Picassent), in order to minimize the tri halomethanes formation. To prove the effectiveness of chlorine dioxide, on the tri halomethanes precursors removal by oxidation, many controls and analytics have been done on the two water treatment plants. On the other hand this study also shows the chlorine dioxide generation method used, as well as its high disinfection efficiency, higher than the chlorine. (Author)

  12. Reprint of "How do components of real cloud water affect aqueous pyruvate oxidation?"

    Science.gov (United States)

    Boris, Alexandra J.; Desyaterik, Yury; Collett, Jeffrey L.

    2015-01-01

    Chemical oxidation of dissolved volatile or semi-volatile organic compounds within fog and cloud droplets in the atmosphere could be a major pathway for secondary organic aerosol (SOA) formation. This proposed pathway consists of: (1) dissolution of organic chemicals from the gas phase into a droplet; (2) reaction with an aqueous phase oxidant to yield low volatility products; and (3) formation of particle phase organic matter as the droplet evaporates. The common approach to simulating aqueous SOA (aqSOA) reactions is photo-oxidation of laboratory standards in pure water. Reactions leading to aqSOA formation should be studied within real cloud and fog water to determine whether additional competing processes might alter apparent rates of reaction as indicated by rates of reactant loss or product formation. To evaluate and identify the origin of any cloud water matrix effects on one example of observed aqSOA production, pyruvate oxidation experiments simulating aqSOA formation were monitored within pure water, real cloud water samples, and an aqueous solution of inorganic salts. Two analysis methods were used: online electrospray ionization high-resolution time-of-flight mass spectrometry (ESI-HR-ToF-MS), and offline anion exchange chromatography (IC) with quantitative conductivity and qualitative ESI-HR-ToF-MS detection. The apparent rate of oxidation of pyruvate was slowed in cloud water matrices: overall measured degradation rates of pyruvate were lower than in pure water. This can be at least partially accounted for by the observed formation of pyruvate from reactions of other cloud water components. Organic constituents of cloud water also compete for oxidants and/or UV light, contributing to the observed slowed degradation rates of pyruvate. The oxidation of pyruvate was not significantly affected by the presence of inorganic anions (nitrate and sulfate) at cloud-relevant concentrations. Future bulk studies of aqSOA formation reactions using simplified

  13. Cost effective water treatment program in Heavy Water Plant (Manuguru)

    International Nuclear Information System (INIS)

    Mohapatra, C.; Prasada Rao, G.

    2002-01-01

    Water treatment technology is in a state of continuous evolution. The increasing urgency to conserve water and reduce pollution has in recent years produced an enormous demand for new chemical treatment programs and technologies. Heavy water plant (Manuguru) uses water as raw material (about 3000 m 3 /hr) and its treatment and management has benefited the plant in a significant way. It is a fact that if the water treatment is not proper, it can result in deposit formation and corrosion of metals, which can finally leads to production losses. Therefore, before selecting treatment program, complying w.r.t. quality requirements, safety and pollution aspects cost effectiveness shall be examined. The areas where significant benefits are derived, are raw water treatment using polyelectrolyte instead of inorganic coagulant (alum), change over of regenerant of cation exchangers from hydrochloric acid to sulfuric acid and in-house development of cooling water treatment formulation. The advantages and cost effectiveness of these treatments are discussed in detail. Further these treatments has helped the plant in achieving zero discharge and indirectly increased cost reduction of final product (heavy water); the dosage of 3 ppm of polyelectrolyte can replace 90 ppm alum at turbidity level of 300 NTU of raw water which has resulted in cost saving of Rs. 15-20 lakhs in a year beside other advantages; the change over of regenerant from HCl to H 2 SO 4 will result in cost saving of at least Rs.1.4 crore a year besides other advantages; the change over to proprietary formulation to in-house formulation in cooling water treatment has resulted in a saving about Rs.11 lakhs a year. To achieve the above objectives in a sustainable way the performance results are being monitored. (author)

  14. Destruction of microcystins by conventional and advanced oxidation processes: A review

    DEFF Research Database (Denmark)

    Sharma, Virender K.; Triantis, Theodoros M.; Antoniou, Maria G.

    2012-01-01

    oxidants is strongly affected by water quality parameters like pH, DOC and oxidant dose. Although there is a general trend for MCs oxidation (ozone>permanganate>chlorine>>>chlorine-based oxidants), the selection of the appropriate oxidant for toxin elimination during water treatment should be assessed...

  15. Detection of oxidative hair treatment using fluorescence microscopy.

    Science.gov (United States)

    Witt, Silvana; Wunder, Cora; Paulke, Alexander; Verhoff, Marcel A; Schubert-Zsilavecz, Manfred; Toennes, Stefan W

    2016-08-01

    In assessing abstinence from drug or alcohol abuse, hair analysis plays an important role. Cosmetic hair treatment influences the content of deposited drugs which is not always detectable during analysis. Since oxidation of melanin leads to an increase in fluorescence, a microscopic method was developed to distinguish natural from cosmetically treated hair. For validation, natural hair samples were treated with different types of cosmetics and inspected by fluorescence microscopy. Hair samples from 20 volunteers with documented cosmetic treatment and as a proof of concept 100 hair samples from forensic cases were analyzed by this method. Apart from autofluorescence with excitation at 365 nm, no obvious fluorescence was observed in untreated hair samples. Tinting and a natural plant product had no influence on fluorescence, but dyeing procedures including oxidation led to a marked increase in fluorescence. Proof of cosmetic treatment was achieved in hair samples from the 20 volunteers. In 100 forensic cases, 13 samples were characterized as oxidatively treated, which was in accordance with the respective disclosure except for one case where treatment was not admitted. This fluorescence microscopic procedure proved to be fast, easy, and reliable to identify oxidatively treated hair samples, which must be considered especially in evaluating cases of negative drug results. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  16. Molecular water oxidation mechanisms followed by transition metals: state of the art.

    Science.gov (United States)

    Sala, Xavier; Maji, Somnath; Bofill, Roger; García-Antón, Jordi; Escriche, Lluís; Llobet, Antoni

    2014-02-18

    One clean alternative to fossil fuels would be to split water using sunlight. However, to achieve this goal, researchers still need to fully understand and control several key chemical reactions. One of them is the catalytic oxidation of water to molecular oxygen, which also occurs at the oxygen evolving center of photosystem II in green plants and algae. Despite its importance for biology and renewable energy, the mechanism of this reaction is not fully understood. Transition metal water oxidation catalysts in homogeneous media offer a superb platform for researchers to investigate and extract the crucial information to describe the different steps involved in this complex reaction accurately. The mechanistic information extracted at a molecular level allows researchers to understand both the factors that govern this reaction and the ones that derail the system to cause decomposition. As a result, rugged and efficient water oxidation catalysts with potential technological applications can be developed. In this Account, we discuss the current mechanistic understanding of the water oxidation reaction catalyzed by transition metals in the homogeneous phase, based on work developed in our laboratories and complemented by research from other groups. Rather than reviewing all of the catalysts described to date, we focus systematically on the several key elements and their rationale from molecules studied in homogeneous media. We organize these catalysts based on how the crucial oxygen-oxygen bond step takes place, whether via a water nucleophilic attack or via the interaction of two M-O units, rather than based on the nuclearity of the water oxidation catalysts. Furthermore we have used DFT methodology to characterize key intermediates and transition states. The combination of both theory and experiments has allowed us to get a complete view of the water oxidation cycle for the different catalysts studied. Finally, we also describe the various deactivation pathways for

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

    KAUST Repository

    Sun, Ke

    2015-03-11

    Reactively sputtered nickel oxide (NiOx) films provide transparent, antireflective, electrically conductive, chemically stable coatings that also are highly active electrocatalysts for the oxidation of water to O2(g). These NiOx coatings provide protective layers on a variety of technologically important semiconducting photoanodes, including textured crystalline Si passivated by amorphous silicon, crystalline n-type cadmium telluride, and hydrogenated amorphous silicon. Under anodic operation in 1.0 M aqueous potassium hydroxide (pH 14) in the presence of simulated sunlight, the NiOx films stabilized all of these self-passivating, high-efficiency semiconducting photoelectrodes for >100 h of sustained, quantitative solar-driven oxidation of water to O2(g). © 2015, National Academy of Sciences. All rights reserved.

  18. Heat treatments of irradiated uranium oxide in a pressurised water reactor (P.W.R.): swelling and fission gas release

    International Nuclear Information System (INIS)

    Zacharie, I.

    1997-01-01

    In order to keep pressurised water reactors at a top level of safety, it is necessary to understand the chemical and mechanical interaction between the cladding and the fuel pellet due to a temperature increase during a rapid change in reactor. In this process, the swelling of uranium oxide plays an important role. It comes from a bubble precipitation of fission gases which are released when they are in contact with the outside. Therefore, the aim of this thesis consists in acquiring a better understanding of the mechanisms which come into play. Uranium oxide samples, from a two cycles irradiated fuel, first have been thermal treated between 1000 deg C and 1700 deg C for 5 minutes to ten hours. The gas release amount related to time has been measured for each treatment. The comparison of the experimental results with a numerical model has proved satisfactory: it seems that the gases release, after the formation of intergranular tunnels, is controlled by the diffusion phenomena. Afterwards, the swelling was measured on the samples. The microscopic examination shows that the bubbles are located in the grain boundaries and have a lenticular shape. The swelling can be explained by the bubbles coalescence and a model was developed based on this observation. An equation allows to calculate the intergranular swelling in function of time and temperature. The study gives the opportunity to predict the fission gases behaviour during a fuel temperature increase. (author)

  19. Control strategies for nitrous oxide emissions reduction on wastewater treatment plants operation.

    Science.gov (United States)

    Santín, I; Barbu, M; Pedret, C; Vilanova, R

    2017-11-15

    The present paper focused on reducing greenhouse gases emissions in wastewater treatment plants operation by application of suitable control strategies. Specifically, the objective is to reduce nitrous oxide emissions during the nitrification process. Incomplete nitrification in the aerobic tanks can lead to an accumulation of nitrite that triggers the nitrous oxide emissions. In order to avoid the peaks of nitrous oxide emissions, this paper proposes a cascade control configuration by manipulating the dissolved oxygen set-points in the aerobic tanks. This control strategy is combined with ammonia cascade control already applied in the literature. This is performed with the objective to take also into account effluent pollutants and operational costs. In addition, other greenhouse gases emissions sources are also evaluated. Results have been obtained by simulation, using a modified version of Benchmark Simulation Model no. 2, which takes into account greenhouse gases emissions. This is called Benchmark Simulation Model no. 2 Gas. The results show that the proposed control strategies are able to reduce by 29.86% of nitrous oxide emissions compared to the default control strategy, while maintaining a satisfactory trade-off between water quality and costs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Oxidation of oily sludge in supercritical water

    International Nuclear Information System (INIS)

    Cui Baochen; Cui Fuyi; Jing Guolin; Xu Shengli; Huo Weijing; Liu Shuzhi

    2009-01-01

    The oxidation of oily sludge in supercritical water is performed in a batch reactor at reaction temperatures between 663 and 723 K, the reaction times between 1 and 10 min and pressure between 23 and 27 MPa. Effect of reaction parameters such as reaction time, temperature, pressure, O 2 excess and initial COD on oxidation of oily sludge is investigated. The results indicate that chemical oxygen demand (COD) removal rate of 92% can be reached in 10 min. COD removal rate increases as the reaction time, temperature and initial COD increase. Pressure and O 2 excess have no remarkable affect on reaction. By taking into account the dependence of reaction rate on COD concentration, a global power-law rate expression was regressed from experimental data. The resulting pre-exponential factor was 8.99 x 10 14 (mol L -1 ) -0.405 s -1 ; the activation energy was 213.13 ± 1.33 kJ/mol; and the reaction order for oily sludge (based on COD) is 1.405. It was concluded that supercritical water oxidation (SCWO) is a rapidly emerging oily sludge processing technology.

  1. Treatment of statin compounds by advanced oxidation processes: Kinetic considerations and destruction mechanisms

    Science.gov (United States)

    Razavi, Behnaz; Song, Weihua; Santoke, Hanoz; Cooper, William J.

    2011-03-01

    This study examined the use of advanced oxidation/reduction processes (AO/RPs) for the destruction of cholesterol lowering statin pharmaceuticals. AO/RPs which utilize the oxidizing hydroxyl radical ( rad OH) and reducing aqueous electron (e -aq), to degrade chemical contaminants are alternatives to traditional water treatment methods, and are alternatives as water reuse becomes more generally implemented. Four major statin pharmaceuticals, fluvastatin, lovastatin, pravastatin and simvastatin, were studied, and the absolute bimolecular reaction rate constants with rad OH determined, (6.96±0.16)×10 9, (2.92±0.06)×10 9, (4.16±0.13)×10 9, and (3.13±0.15)×10 9 M -1 s -1, and for e -aq (2.31±0.06)×10 9, (0.45±0.01)×10 9, (1.26±0.01)×10 9, and (0.69±0.02)×10 9 M -1 s -1, respectively. To provide additional information on the radicals formed upon oxidation, transient spectra were measured and the overall reaction efficiency determined. Radical-based destruction mechanisms for destruction of the statins are proposed based on the LC-MS determination of the stable reaction by-products formed using 137Cs γ-irradiation of statin solutions. Knowing the reaction rates, reaction efficiencies and destruction mechanisms of these compounds is essential for the consideration of the use of advanced oxidation/reduction processes for the destruction of statins in aqueous systems.

  2. Treatment of statin compounds by advanced oxidation processes: Kinetic considerations and destruction mechanisms

    International Nuclear Information System (INIS)

    Razavi, Behnaz; Song Weihua; Santoke, Hanoz; Cooper, William J.

    2011-01-01

    This study examined the use of advanced oxidation/reduction processes (AO/RPs) for the destruction of cholesterol lowering statin pharmaceuticals. AO/RPs which utilize the oxidizing hydroxyl radical ( · OH) and reducing aqueous electron (e - aq ), to degrade chemical contaminants are alternatives to traditional water treatment methods, and are alternatives as water reuse becomes more generally implemented. Four major statin pharmaceuticals, fluvastatin, lovastatin, pravastatin and simvastatin, were studied, and the absolute bimolecular reaction rate constants with · OH determined, (6.96±0.16)x10 9 , (2.92±0.06)x10 9 , (4.16±0.13)x10 9 , and (3.13±0.15)x10 9 M -1 s -1 , and for e - aq (2.31±0.06)x10 9 , (0.45±0.01)x10 9 , (1.26±0.01)x10 9 , and (0.69±0.02)x10 9 M -1 s -1 , respectively. To provide additional information on the radicals formed upon oxidation, transient spectra were measured and the overall reaction efficiency determined. Radical-based destruction mechanisms for destruction of the statins are proposed based on the LC-MS determination of the stable reaction by-products formed using 137 Cs γ-irradiation of statin solutions. Knowing the reaction rates, reaction efficiencies and destruction mechanisms of these compounds is essential for the consideration of the use of advanced oxidation/reduction processes for the destruction of statins in aqueous systems.

  3. Effect of ozonation on the removal of cyanobacterial toxins during drinking water treatment.

    Science.gov (United States)

    Hoeger, Stefan J; Dietrich, Daniel R; Hitzfeld, Bettina C

    2002-01-01

    Water treatment plants faced with toxic cyanobacteria have to be able to remove cyanotoxins from raw water. In this study we investigated the efficacy of ozonation coupled with various filtration steps under different cyanobacterial bloom conditions. Cyanobacteria were ozonated in a laboratory-scale batch reactor modeled on a system used by a modern waterworks, with subsequent activated carbon and sand filtration steps. The presence of cyanobacterial toxins (microcystins) was determined using the protein phosphatase inhibition assay. We found that ozone concentrations of at least 1.5 mg/L were required to provide enough oxidation potential to destroy the toxin present in 5 X 10(5 )Microcystis aeruginosa cells/mL [total organic carbon (TOC), 1.56 mg/L]. High raw water TOC was shown to reduce the efficiency of free toxin oxidation and destruction. In addition, ozonation of raw waters containing high cyanobacteria cell densities will result in cell lysis and liberation of intracellular toxins. Thus, we emphasize that only regular and simultaneous monitoring of TOC/dissolved organic carbon and cyanobacterial cell densities, in conjunction with online residual O(3) concentration determination and efficient filtration steps, can ensure the provision of safe drinking water from surface waters contaminated with toxic cyanobacterial blooms. PMID:12417484

  4. Small-scale, hydrogen-oxidizing-denitrifying bioreactor for treatment of nitrate-contaminated drinking water.

    Science.gov (United States)

    Smith, Richard L; Buckwalter, Seanne P; Repert, Deborah A; Miller, Daniel N

    2005-05-01

    Nitrate removal by hydrogen-coupled denitrification was examined using flow-through, packed-bed bioreactors to develop a small-scale, cost effective system for treating nitrate-contaminated drinking-water supplies. Nitrate removal was accomplished using a Rhodocyclus sp., strain HOD 5, isolated from a sole-source drinking-water aquifer. The autotrophic capacity of the purple non-sulfur photosynthetic bacterium made it particularly adept for this purpose. Initial tests used a commercial bioreactor filled with glass beads and countercurrent, non-sterile flow of an autotrophic, air-saturated, growth medium and hydrogen gas. Complete removal of 2 mM nitrate was achieved for more than 300 days of operation at a 2-h retention time. A low-cost hydrogen generator/bioreactor system was then constructed from readily available materials as a water treatment approach using the Rhodocyclus strain. After initial tests with the growth medium, the constructed system was tested using nitrate-amended drinking water obtained from fractured granite and sandstone aquifers, with moderate and low TDS loads, respectively. Incomplete nitrate removal was evident in both water types, with high-nitrite concentrations in the bioreactor output, due to a pH increase, which inhibited nitrite reduction. This was rectified by including carbon dioxide in the hydrogen stream. Additionally, complete nitrate removal was accomplished with wastewater-impacted surface water, with a concurrent decrease in dissolved organic carbon. The results of this study using three chemically distinct water supplies demonstrate that hydrogen-coupled denitrification can serve as the basis for small-scale remediation and that pilot-scale testing might be the next logical step.

  5. Changes of turbidity during the phenol oxidation by photo-Fenton treatment.

    Science.gov (United States)

    Villota, Natalia; Camarero, Luis M; Lomas, Jose M; Perez, Jonatan

    2014-11-01

    Turbidity presented by phenol solutions oxidized with Fenton reagent shows the tendency of a first order intermediate kinetics. Thus, turbidity can be considered a representative parameter of the presence of intermediate oxidation species, which are generated along the decomposition of toxic and reluctant contaminants, such as phenol. Moreover, that parameter presents a linear dependence with the catalyst dosage, but is also determined by the initial contaminant load. When analyzing the oxidation mechanism of phenol, it is found that the maximum turbidity occurs when the treatment is carried out at oxidant to phenol molar ratios R = 4.0. These oxidation conditions correspond to the presence of a reaction mixture mainly composed of dihydroxylated rings, precursors of the muconic acid formation. The oxidation via "para" comprises the formation reactions of charge transfer complexes (quinhydrone), between the para-dihydroxylated intermediates (hydroquinone) and the para-substituted quinones (p-benzoquinone), which are quite unstable and reactive species, quickly decomposed into hydroxyhydroquinones. Working with oxidant ratios up to R = 6.0, the maximum observed value of turbidity in the oxidized solutions is kept almost constant. It is found that, in these conditions, the pyrogallol formation is maximal, what is generated through the degradation of ortho-species (catechol and ortho-benzoquinone) and meta-substituted (resorcinol). Operating with ratios over R = 6.0, these intermediates are decomposed into biodegradable acids, generating lower turbidity in the solution. Then, the residual turbidity is a function of the molar ratio of the ferrous ions vs. moles of oxidant utilized in the essays, that lets to estimate the stoichiometric dosage of catalyst as 20 mg/L at pH = 3.0, whereas operating in stoichiometric conditions, R = 14.0, the residual turbidity of water results almost null.

  6. Photo- and chemocatalytic oxidation of dyes in water.

    Science.gov (United States)

    Du, Wei-Ning; Chen, Shyi-Tien

    2018-01-15

    Three commonly used dyes, Acid Red-114 (AR-114), Reactive Black-5 (RB-5), and Disperse Black EX-SF (DB-EX-SF), were treated in a pH-neutral liquid with ultraviolet (UV) light by two reactive methods: photocatalysis with titanium dioxide (TiO 2 ), and/or chemocatalysis with hydrogen peroxide (H 2 O 2 ) as the oxidant and various ferrous-based electron mediators as catalysts. Important factors for dye oxidation were determined through bifactorial experiments. The optimum combinations and doses of the three key reagents, namely TiO 2 , H 2 O 2 , and EDTA-Fe, were also determined. The degradation kinetics of the studied dyes at their optimum doses reveal that the oxidation reactions are pseudo-first-order in nature, and that certain dyes are selectively degraded more by one method than the other. The overall results suggest that co-treatment using more than one oxidative method is beneficial for the treatment of wastewater from dyeing processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Ferrate(VI) as a greener oxidant: Electrochemical generation and treatment of phenol.

    Science.gov (United States)

    Sun, Xuhui; Zhang, Qi; Liang, He; Ying, Li; Xiangxu, Meng; Sharma, Virender K

    2016-12-05

    Ferrate(VI) (Fe(VI)O4(2-), Fe(VI)) is a greener oxidant in the treatment of drinking water and wastewater. The electrochemical synthesis of Fe(VI) may be considered environmentally friendly because it involves one-step process to convert Fe(0) to Fe(VI) without using harmful chemicals. Electrolysis was performed by using a sponge iron as an anode in NaOH solution at different ionic strengths. The cyclic voltammetric (CV) curves showed that the sponge iron had higher electrical activity than the grey cast iron. The optimum current density was 0.054mAcm(-2) in 10M NaOH solution, which is much lower than the electrolyte concentrations used in other electrode materials. A comparison of current efficiency and energy consumption was conducted and is briefly discussed. The generated ferrate solution was applied to degrade phenol in water at two levels (2mgL(-1) and 5mgL(-1)). The maximum removal efficiency was ∼70% and the optimum pH for phenol treatment was 9.0. Experiments on phenol removal using conventional coagulants (ferric chloride (FeCl3) and polyaluminium chloride (PAC)) were performed independently to demonstrate that removal of phenol by Fe(VI) occurred mainly by oxidative transformation. A combination of Fe(VI) and coagulant may be advantageous in enhancing removal efficiency, adjusting pH, and facilitating flocculation. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. From Earth to Space: Application of Biological Treatment for the Removal of Ammonia from Water

    Science.gov (United States)

    Pickering, Karen; Adam, Niklas; White, Dawn; Ghosh, Amlan; Seidel, Chad

    2014-01-01

    Managing ammonia is often a challenge in both drinking water and wastewater treatment facilities. Ammonia is unregulated in drinking water, but its presence may result in numerous water quality issues in the distribution system such as loss of residual disinfectant, nitrification, and corrosion. Ammonia concentrations need to be managed in wastewater effluent to sustain the health of receiving water bodies. Biological treatment involves the microbiological oxidation of ammonia to nitrate through a two-step process. While nitrification is common in the environment, and nitrifying bacteria can grow rapidly on filtration media, appropriate conditions, such as the presence of dissolved oxygen and required nutrients, need to be established. This presentation will highlight results from two ongoing research programs - one at NASA's Johnson Space Center, and the other at a drinking water facility in California. Both programs are designed to demonstrate nitrification through biological treatment. The objective of NASA's research is to be able to recycle wastewater to potable water for spaceflight missions. To this end, a biological water processor (BWP) has been integrated with a forward osmosis secondary treatment system (FOST). Bacteria mineralize organic carbon to carbon dioxide as well as ammonia-nitrogen present in the wastewater to nitrogen gas, through a combination of nitrification and denitrification. The effluent from the BWP system is low in organic contaminants, but high in total dissolved solids. The FOST system, integrated downstream of the BWP, removes dissolved solids through a combination of concentration-driven forward osmosis and pressure driven reverse osmosis. The integrated system testing planned for this year is expected to produce water that requires only a polishing step to meet potable water requirements for spaceflight. The pilot study in California is being conducted on Golden State Water Company's Yukon wells that have hydrogen sulfide odor

  9. Industrial water pollution, water environment treatment, and health risks in China.

    Science.gov (United States)

    Wang, Qing; Yang, Zhiming

    2016-11-01

    The negative health effects of water pollution remain a major source of morbidity and mortality in China. The Chinese government is making great efforts to strengthen water environment treatment; however, no studies have evaluated the effects of water treatment on human health by water pollution in China. This study evaluated the association between water pollution and health outcomes, and determined the extent to which environmental regulations on water pollution may lead to health benefits. Data were extracted from the 2011 and 2013 China Health and Retirement Longitudinal Study (CHARLS). Random effects model and random effects Logit model were applied to study the relationship between health and water pollution, while a Mediator model was used to estimate the effects of environmental water treatment on health outcomes by the intensity of water pollution. Unsurprisingly, water pollution was negatively associated with health outcomes, and the common pollutants in industrial wastewater had differential impacts on health outcomes. The effects were stronger for low-income respondents. Water environment treatment led to improved health outcomes among Chinese people. Reduced water pollution mediated the associations between water environment treatment and health outcomes. The results of this study offer compelling evidence to support treatment of water pollution in China. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Alpha Radiolysis of Sorbed Water on Uranium Oxides and Uranium Oxyfluorides

    Energy Technology Data Exchange (ETDEWEB)

    Icenhour, A.S.

    2003-09-10

    The radiolysis of sorbed water and other impurities contained in actinide oxides has been the focus of a number of studies related to the establishment of criteria for the safe storage and transport of these materials. Gamma radiolysis studies have previously been performed on uranium oxides and oxyfluorides (UO{sub 3}, U{sub 3}O{sub 8}, and UO{sub 2}F{sub 2}) to evaluate the long-term storage characteristics of {sup 233}U. This report describes a similar study for alpha radiolysis. Uranium oxides and oxyfluorides (with {sup 238}U as the surrogate for {sup 233}U) were subjected to relatively high alpha radiation doses (235 to 634 MGy) by doping with {sup 244}Cm. The typical irradiation time for these samples was about 1.5 years, which would be equivalent to more than 50 years irradiation by a {sup 233}U sample. Both dry and wet (up to 10 wt % water) samples were examined in an effort to identify the gas pressure and composition changes that occurred as a result of radiolysis. This study shows that several competing reactions occur during radiolysis, with the net effect that only very low pressures of hydrogen, nitrogen, and carbon dioxide are generated from the water, nitrate, and carbon impurities, respectively, associated with the oxides. In the absence of nitrate impurities, no pressures greater than 1000 torr are generated. Usually, however, the oxygen in the air atmosphere over the oxides is consumed with the corresponding oxidation of the uranium oxide. In the presence of up to 10 wt % water, the oxides first show a small pressure rise followed by a net decrease due to the oxygen consumption and the attainment of a steady-state pressure where the rate of generation of gaseous components is balanced by their recombination and/or consumption in the oxide phase. These results clearly demonstrate that alpha radiolysis of either wet or dry {sup 233}U oxides will not produce deleterious pressures or gaseous components that could compromise the long-term storage of

  11. Impact of diatomite on the slightly polluted algae-containing raw water treatment process using ozone oxidation coupled with polyaluminum chloride coagulation.

    Science.gov (United States)

    Hu, Wenchao; Wu, Chunde; Jia, Aiyin; Zhang, Zhilin; Chen, Fang

    2014-01-01

    The impact of adding diatomite on the treatment performance of slightly polluted algae-containing raw water using ozone pre-oxidation and polyaluminum chloride (PAC) coagulation was investigated. Results demonstrated that the addition of diatomite is advantageous due to reduction of the PAC dose (58.33%) and improvement of the removal efficiency of algae, turbidity, and dissolved organic matter (DOM) in raw water. When the ozone concentration was 1.0 mg L⁻¹ and the PAC dosage was 2.5 mg L⁻¹, the removal rates of algae, turbidity, UV254, and TOC were improved by 6.39%, 7.06%, 6.76%, and 4.03%, respectively, with the addition of 0.4 g L⁻¹ diatomite. It has been found that the DOM presented in the Pearl River raw water mainly consisted of small molecules ( 50 kDa). After adding diatomite (0.4 g L⁻¹), the additional removal of 5.77% TOC and 14.82% UV254 for small molecules (50 kDa) could be achieved, respectively, at an ozone concentration of 1.0 mg L⁻¹ and a PAC dose of 2.5 mg L⁻¹. The growth of anabaena flos-aquae (A.F.) was observed by an atomic force microscope (AFM) before and after adding diatomite. AFM images demonstrate that diatomite may have a certain adsorption on A.F.

  12. SONO-OXIDATIVE PRE-TREATMENT OF WASTE ACTIVATED SLUDGE BEFORE ANAEROBIC BIODEGRADATION

    Directory of Open Access Journals (Sweden)

    S. Şahinkaya

    Full Text Available Abstract The effects of sonication, potassium ferrate (K2FeO4 oxidation and their simultaneous combination (called "sono-oxidative pre-treatment" on chemical properties and anaerobic digestion of waste activated sludge (WAS were investigated and compared comprehensively. Based on chemical parameters, the optimum operating conditions were found to be 0.3 g K2FeO4/g total solids (TS dosage for 2-h individual K2FeO4 oxidation, 0.50 W/mL ultrasonic power density for 10-min individual sonication and, lastly, the combination of 2.5-min sonication at 0.75 W/mL ultrasonic power density with 2-h chemical oxidation at 0.3 g K2FeO4/g TS dosage for sono-oxidative pre-treatment. The disintegration efficiencies of these methods under the optimized conditions were in the following descending order: 37.8% for sono-oxidative pre-treatment > 26.3% for sonication > 13.1% for K2FeO4 oxidation. The influences of these methods on anaerobic biodegradability were tested with the biochemical methane potential assay. It was seen that the cumulative methane production increased by 9.2% in the K2FeO4 oxidation reactor, 15.8% in the sonicated reactor and 18.6% in the reactor with sono-oxidative pre-treatment, compared to the control (untreated reactor.

  13. Aging of iron (hydr)oxides by heat treatment and effects on heavy metal binding

    DEFF Research Database (Denmark)

    Sørensen, Mette Abildgaard; Starckpoole, M. M.; Frenkel, A. I.

    2000-01-01

    their transformations caused by heat treatment prior to disposal or aging at a proper disposal site. The transformations were investigated by XRD, SEM, XANES, EXAFS, surface area measurements, pH static leaching tests, and extractions with oxalate and weak hydrochloric acid. It was found that at 600 and 900 °C the iron...... oxides were transformed to hematite, which had a greater thermodynamic stability but less surface area than the initial products. Heat treatment also caused some volatilization of heavy metals (most notably, Hg). Leaching with water at pH 9 (L/S 10, 24 h) and weak acid extraction showed that heat...

  14. Ozone oxidation of oestrogenic active substances in wastewater and drinking water.

    Science.gov (United States)

    Baig, S; Hansmann, G; Paolini, B

    2008-01-01

    Ozone oxidation is proven to be an effective solution for the degradation of selected oestrogenic active substances detected in secondary wastewaters such as beta-oestradiol, oestrone, oestriol, 17-alpha-ethinyloestradiol, mestranol, daidzeine, beta-sitosterol, bisphenol A, norethisterone, 4-tert-octylphenol and 4-iso-nonylphenol, up to their limit of detection. The matrix-effect of wastewater was investigated performing ozone experiments under batch mode and continuous mode using drinking water and a wastewater issued from a local plant both spiked with the non-detected substances. The results obtained indicate that the wastewater matrix greatly affects the kinetics of ozone reaction with these substances but does not really change the related reactivity scale. The ozone dose corresponding to the full conversion of target EDCs consequently increases as their oxidation takes place competing with reactions of background pollutants represented by the COD and DOC content. However, a usual dose close to 12 mg/L was found sufficient to provide high degradation yields for all substances studied while 35% of COD was removed. This is a contribution to the numerous current works focused on technologies able to improve the quality of water discharged from wastewater treatment plants, both considering conventional parameters and emerging contaminants. IWA Publishing 2008.

  15. Waste treatment using molten salt oxidation

    International Nuclear Information System (INIS)

    Navratil, J.D.; Stewart, A.E.

    1996-01-01

    MSO technology can be characterized as a submerged oxidation process; the basic concept is to introduce air and wastes into a bed of molten salt, oxidize the organic wastes in the molten salt, use the heat of oxidation to keep the salt molten and remove the salt for disposal or processing and recycling. The molten salt (usually sodium carbonate at 900-1000 C) provides four waste management functions: providing a heat transfer medium, catalyzing the oxidation reaction, preventing the formation of acid gases by forming stable salts, and efficiently capturing ash particles and radioactive materials by the combined effects of wetting, encapsulation and dissolution. The MSO process requires no wet scrubbing system for off-gas treatment. The process has been developed through bench-scale and pilot-scale testing, with successful destruction demonstration of a wide variety of hazardous and mixed (radioactive and hazardous wastes). (author). 24 refs, 2 tabs, 2 figs

  16. Supramolecular water oxidation with rubda-based catalysts

    KAUST Repository

    Richmond, Craig J.; Matheu, Roc; Poater, Albert; Falivene, Laura; Benet-Buchholz, Jordi; Sala, Xavier; Cavallo, Luigi; Llobet, Antoni A.

    2014-01-01

    Extremely slow and extremely fast new water oxidation catalysts based on the Rubda (bda = 2,2′-bipyri-dine-6,6′-dicarboxylate) systems are reported with turnover frequencies in the range of 1 and 900 cycless"1, respectively. Detailed analyses

  17. Disinfection of Spacecraft Potable Water Systems by Photocatalytic Oxidation Using UV-A Light Emitting Diodes

    Science.gov (United States)

    Birmele, Michele N.; O'Neal, Jeremy A.; Roberts, Michael S.

    2011-01-01

    Ultraviolet (UV) light has long been used in terrestrial water treatment systems for photodisinfection and the removal of organic compounds by several processes including photoadsorption, photolysis, and photocatalytic oxidation/reduction. Despite its effectiveness for water treatment, UV has not been explored for spacecraft applications because of concerns about the safety and reliability of mercury-containing UV lamps. However, recent advances in ultraviolet light emitting diodes (UV LEDs) have enabled the utilization of nanomaterials that possess the appropriate optical properties for the manufacture of LEDs capable of producing monochromatic light at germicidal wavelengths. This report describes the testing of a commercial-off-the-shelf, high power Nichia UV-A LED (250mW A365nnJ for the excitation of titanium dioxide as a point-of-use (POD) disinfection device in a potable water system. The combination of an immobilized, high surface area photocatalyst with a UV-A LED is promising for potable water system disinfection since toxic chemicals and resupply requirements are reduced. No additional consumables like chemical biocides, absorption columns, or filters are required to disinfect and/or remove potentially toxic disinfectants from the potable water prior to use. Experiments were conducted in a static test stand consisting of a polypropylene microtiter plate containing 3mm glass balls coated with titanium dioxide. Wells filled with water were exposed to ultraviolet light from an actively-cooled UV-A LED positioned above each well and inoculated with six individual challenge microorganisms recovered from the International Space Station (ISS): Burkholderia cepacia, Cupriavidus metallidurans, Methylobacterium fujisawaense, Pseudomonas aeruginosa, Sphingomonas paucimobilis and Wautersia basilensis. Exposure to the Nichia UV-A LED with photocatalytic oxidation resulted in a complete (>7-log) reduction of each challenge bacteria population in UV-A LEDs and semi

  18. Neutrophilic iron-oxidizing bacteria: occurrence and relevance in biological drinking water treatment

    DEFF Research Database (Denmark)

    Gülay, Arda; Musovic, Sanin; Albrechtsen, Hans-Jørgen

    2013-01-01

    Rapid sand filtration (RSF) is an economical way to treat anoxic groundwater around the world. It consists of groundwater aeration followed by passage through a sand filter. The oxidation and removal of ferrous iron, which is commonly found in anoxic groundwaters, is often believed to be a fully...... role of FeOB in iron removal at waterworks using RSF technologies....... physicochemical process. However, persistently low temperatures in RSF across Denmark may negatively affect the kinetics of chemical oxidation. The slower chemical oxidation of ferrous iron may increase the chances for iron bioconversion by neutrophilic iron-oxidizing bacteria (FeOB), which are found naturally...

  19. A comparison study of the start-up of a MnOx filter for catalytic oxidative removal of ammonium from groundwater and surface water.

    Science.gov (United States)

    Cheng, Ya; Li, Ye; Huang, Tinglin; Sun, Yuankui; Shi, Xinxin; Shao, Yuezong

    2018-03-01

    As an efficient method for ammonium (NH 4 + ) removal, contact catalytic oxidation technology has drawn much attention recently, due to its good low temperature resistance and short start-up period. Two identical filters were employed to compare the process for ammonium removal during the start-up period for ammonium removal in groundwater (Filter-N) and surface water (Filter-S) treatment. Two types of source water (groundwater and surface water) were used as the feed waters for the filtration trials. Although the same initiating method was used, Filter-N exhibited much better ammonium removal performance than Filter-S. The differences in catalytic activity among these two filters were probed using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and compositional analysis. XRD results indicated that different manganese oxide species were formed in Filter-N and Filter-S. Furthermore, the Mn3p XPS spectra taken on the surface of the filter films revealed that the average manganese valence of the inactive manganese oxide film collected from Filter-S (FS-MnO x ) was higher than in the film collected from Filter-N (FN-MnO x ). Mn(IV) was identified as the predominant oxidation state in FS-MnO x and Mn(III) was identified as the predominant oxidation state in FN-MnO x . The results of compositional analyses suggested that polyaluminum ferric chloride (PAFC) used during the surface water treatment was an important factor in the mineralogy and reactivity of MnO x . This study provides the theoretical basis for promoting the wide application of the technology and has great practical significance. Copyright © 2017. Published by Elsevier B.V.

  20. Phenol Contaminated Water Treatment on Several Modified Dimensionally Stable Anodes.

    Science.gov (United States)

    Jayathilaka, Pavithra Bhakthi; Hapuhinna, Kushani Umanga Kumari; Bandara, Athula; Nanayakkara, Nadeeshani; Subasinghe, Nalaka Deepal

    2017-08-01

      Phenolic compounds are some of the most common hazardous organics in wastewater. Removal of these pollutants is important. Physiochemical method such as electrochemical oxidation on dimensionally stable anodes is more convenient in removing such organic pollutants. Therefore, this study focuses on development of three different anodes for phenol contaminated water treatment. The performances of steel/IrO2, steel/IrO2-Sb2O3, and Ti/IrO2-Sb2O3 anodes were tested and compared. Nearly 50, 76, and 84% of chemical oxygen demand removal efficiencies were observed for steel/IrO2, steel/IrO2-Sb2O3, and Ti/IrO2-Sb2O3 anodes, respectively. The formation of intermediates was monitored for three anodes and the Ti/IrO2-Sb2O3 anode showed the most promising results. Findings suggest that the developed anode materials can enhance phenol oxidation efficiency and that mixed metal oxide layer has major influence on the anode. Among the selected metal oxide mixtures IrO2-Sb2O3 was the most suitable under given experimental conditions.

  1. Neutrophilic Iron Oxidizing Bacteria: Occurrence and Relevance in Biological Drinking Water Treatment

    DEFF Research Database (Denmark)

    Gülay, Arda; Musovic, Sanin; Albrechtsen, Hans-Jørgen

    Rapid sand filtration (RSF) is an economical way to treat anoxic groundwater around the world. It consists of groundwater aeration followed by passage through a sand filter. The oxidation and removal of ferrous iron, which is commonly found in anoxic groundwaters, is often believed to be a fully......, neutrophilic iron oxidizers were present at the level of up to 7 105 cells per gram sediment. The spatial abundance and diversity of FeOB inferred by DGGE fingerprinting differed greatly both between and within individual sand filters. The results suggest a larger than assumed role of FeOB in iron removal...... physicochemical process. However, persistently low temperatures in RSF across Denmark may negatively affect the kinetics of chemical oxidation. The slower chemical oxidation of ferrous iron may increase the chances for iron bioconversion by neutrophilic iron-oxidizing bacteria (FeOB), which are found naturally...

  2. Water: from the source to the treatment plan

    Science.gov (United States)

    Marquet, V.; Baude, I.

    2012-04-01

    As a biology and geology teacher, I have worked on water, from the source to the treatment plant, with pupils between 14 and 15 years old. Lesson 1. Introduction, the water in Vienna Aim: The pupils have to consider why the water is so important in Vienna (history, economy etc.) Activities: Brainstorming about where and why we use water every day and why the water is different in Vienna. Lesson 2. Soil, rock and water Aim: Permeability/ impermeability of the different layers of earth Activities: The pupils have measure the permeability and porosity of different stones: granite, clay, sand, carbonate and basalt. Lesson 3. Relationship between water's ion composition and the stone's mineralogy Aim: Each water source has the same ion composition as the soil where the water comes from. Activities: Comparison between the stone's mineralogy and ions in water. They had a diagram with the ions of granite, clay, sand, carbonate and basalt and the label of different water. They had to make hypotheses about the type of soil where the water came from. They verified this with a geology map of France and Austria. They have to make a profile of the area where the water comes from. They had to confirm or reject their hypothesis. Lesson 4 .Water-catchment and reservoir rocks Aim: Construction of a confined aquifer and artesian well Activities: With sand, clay and a basin, they have to model a confined aquifer and make an artesian well, using what they have learned in lesson 2. Lesson 5. Organic material breakdown and it's affect on the oxygen levels in an aquatic ecosystem Aim: Evaluate the relationship between oxygen levels and the amount of organic matter in an aquatic ecosystem. Explain the relationship between oxygen levels, bacteria and the breakdown of organic matter using an indicator solution. Activities: Put 5 ml of a different water sample in each tube with 20 drops of methylene blue. Observe the tubes after 1 month. Lesson 6. Visit to the biggest water treatment plant in

  3. The function of advanced treatment process in a drinking water treatment plant with organic matter-polluted source water.

    Science.gov (United States)

    Lin, Huirong; Zhang, Shuting; Zhang, Shenghua; Lin, Wenfang; Yu, Xin

    2017-04-01

    To understand the relationship between chemical and microbial treatment at each treatment step, as well as the relationship between microbial community structure in biofilms in biofilters and their ecological functions, a drinking water plant with severe organic matter-polluted source water was investigated. The bacterial community dynamics of two drinking water supply systems (traditional and advanced treatment processes) in this plant were studied from the source to the product water. Analysis by 454 pyrosequencing was conducted to characterize the bacterial diversity in each step of the treatment processes. The bacterial communities in these two treatment processes were highly diverse. Proteobacteria, which mainly consisted of beta-proteobacteria, was the dominant phylum. The two treatment processes used in the plant could effectively remove organic pollutants and microbial polution, especially the advanced treatment process. Significant differences in the detection of the major groups were observed in the product water samples in the treatment processes. The treatment processes, particularly the biological pretreatment and O 3 -biological activated carbon in the advanced treatment process, highly influenced the microbial community composition and the water quality. Some opportunistic pathogens were found in the water. Nitrogen-relative microorganisms found in the biofilm of filters may perform an important function on the microbial community composition and water quality improvement.

  4. Biochemistry Oxidation Process for Treatment the Simulation of Organic Liquid Radioactive Waste

    International Nuclear Information System (INIS)

    Gunandjar; Zainus Salimin; Sugeng Purnomo; Ratiko

    2010-01-01

    The nuclear industry activities generate the organic liquid wastes such as detergent waste from laundry, solvent waste of 30% TBP (tri-n-butyl phosphate) in kerosene from purification or recovery of uranium from rejection of nuclear fuel element fabrication, and solvent waste containing D 2 EHPA (di-2-ethyl hexyl phosphoric acid) and TOPO (trioctyl phospine oxide) in kerosene from phosphoric acid purification. The wastes are included in category of the hazard and poison materials which also radioactive, so that the wastes have to be treated to detoxification of the hazard and poison materials and decontamination of the radionuclides. The research of biochemistry oxidation process for treatment the simulation of organic liquid radioactive waste from laundry using mixture of aerobe bacteria of bacillus sp, pseudomonas sp, arthrobacter sp, and aeromonas sp have been carried out. The waste containing detergent 1,496 g/Litre, activity 10 -1 Ci/m 3 , with COD (Chemical Oxygen Demand) 128, BOD (Biological Oxygen Demand) 68 and TSS (Total Suspended Solid) 1000 ppm, it is treated by biochemistry oxidation with addition of bacteria which be fed nutrition of nitrogen and phosphor, and aeration. The result show that the bacteria can decompose the detergent to become carbon dioxyde and water so that can fulfill the quality standard of water group-B with content of BOD and COD are 6 and 10 ppm respectively, the time of decomposition is needed 106 hours to be fulfill the quality standard of water. The longer of process time will give bigger the total solid content in sludge, because the biomass generated from the colony of bacteria which life and dead to so much. (author)

  5. Heats of immersion in the thorium oxide-water system at elevated temperatures

    International Nuclear Information System (INIS)

    Holmes, H.F.

    1976-01-01

    The surface properties of ThO 2 were studied by heat of immersion calorimetry at 25 to 200 0 C. Results show that the integral heat of immersion of thorium oxide contains contributions which reflect considerable interaction with several layers of water adjacent to the oxide surface. It would be desirable to know the heat capacity changes which occur in the multilayer adsorption of water on an oxide surface. However, such data are not available and their acquisition would be an extremely difficult task. Structuring (a negative ΔCp) of several layers of water (by increased hydrogen bonding) adjacent to an oxide surface could explain an increase in the heat of immersion as the immersion temperature is increased. The more energetic, heterogeneous, high-surface-area samples are expected to induce more order in the adjacent water layers than the less energetic samples. This interpretation is similar to that offered for the temperature dependence of the heat of solution of the alkali halides

  6. Biological iron oxidation by Gallionella spp. in drinking water production under fully aerated conditions.

    Science.gov (United States)

    de Vet, W W J M; Dinkla, I J T; Rietveld, L C; van Loosdrecht, M C M

    2011-11-01

    Iron oxidation under neutral conditions (pH 6.5-8) may be a homo- or heterogeneous chemically- or a biologically-mediated process. The chemical oxidation is supposed to outpace the biological process under slightly alkaline conditions (pH 7-8). The iron oxidation kinetics and growth of Gallionella spp. - obligatory chemolithotrophic iron oxidizers - were assessed in natural, organic carbon-containing water, in continuous lab-scale reactors and full-scale groundwater trickling filters in the Netherlands. From Gallionella cell numbers determined by qPCR, balances were made for all systems. The homogeneous chemical iron oxidation occurred in accordance with the literature, but was retarded by a low water temperature (13 °C). The contribution of the heterogeneous chemical oxidation was, despite the presence of freshly formed iron oxyhydroxides, much lower than in previous studies in ultrapure water. This could be caused by the adsorption of natural organic matter (NOM) on the iron oxide surfaces. In the oxygen-saturated natural water with a pH ranging from 6.5 to 7.7, Gallionella spp. grew uninhibited and biological iron oxidation was an important, and probably the dominant, process. Gallionella growth was not even inhibited in a full-scale filter after plate aeration. From this we conclude that Gallionella spp. can grow under neutral pH and fully aerated conditions when the chemical iron oxidation is retarded by low water temperature and inhibition of the autocatalytic iron oxidation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Sustainable treatment of municipal waste water

    DEFF Research Database (Denmark)

    Hansen, Peter Augusto; Larsen, Henrik Fred

    The main goal of the EU FP6 NEPTUNE program is to develop new and improve existing waste water treatment technologies (WWTT) and sludge handling technologies for municipal waste water, in accordance with the concepts behind the EU Water Framework Directive. As part of this work, the project.......e. heavy metals, pharmaceuticals and endocrine disruptors) in the waste water. As a novel approach, the potential ecotoxicity and human toxicity impacts from a high number of micropollutants and the potential impacts from pathogens will be included. In total, more that 20 different waste water and sludge...... treatment technologies are to be assessed. This paper will present the first LCA results from running existing life cycle impact assessment (LCIA) methodology on some of the waste water treatment technologies. Keywords: Sustainability, LCA, micropollutants, waste water treatment technologies....

  8. The Manipulation of Hydrophobicity in Catalyst Design for Applications of Aerobic Alcohols Oxidation and Electrocatalytic Water Oxidation

    KAUST Repository

    Chen, Batian

    2016-05-17

    Hydrophobicity is the generalized characteristic of non-polar substances that brings about their exclusion from aqueous phases. This property, entropic in its nature, drives key self-assembly and phase separation processes in water. Protein folding, the formation of DNA double helix, the existence of lipid bilayers and the wetting properties of leaf surfaces are all due to hydrophobic interactions. Inspired by Nature, we aimed to use hydrophobicity for creating novel and improved catalytic systems. (I) A number of fluorous amphiphilic star block-copolymers containing a tris(benzyltriazolylmethyl)amine motif have been prepared. These polymers assembled into well-defined nanostructures in water, and their mode of assembly could be controlled by changing the composition of the polymer. The polymers were used for enzyme-inspired catalysis of alcohol oxidation. (II) An enzyme-inspired catalytic system based on a rationally designed multifunctional surfactant was developed. The resulting micelles feature metal-binding sites and stable free radical moieties as well as fluorous pockets that attract and preconcentrate molecular oxygen. In the presence of copper ions, the micelles effect chemoselective aerobic alcohol oxidation under ambient conditions in water, a transformation that is challenging to achieve nonenzymatically. (III) Development of a facile means of photo/electrocatalytic water splitting is one of the main barriers to establishing of a solar hydrogen economy. Of the two half-reactions involved in splitting water into O2 and H2, water oxidation presents the most challenge due to its mechanistic complexity. A practical water oxidation catalyst must be highly active, yet inexpensive and indefinitely stable under harsh oxidative conditions. Here, I shall describe the synthesis of a library of molecular water oxidation catalysts based on the Co complex of tris(2-benzimidazolylmethyl)amine, (BimH)3. A wide range of catalysts differing in their electronic properties

  9. Removal of organic contaminants from secondary effluent by anodic oxidation with a boron-doped diamond anode as tertiary treatment

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Segura, Sergi, E-mail: sergigarcia@ub.edu [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia); Laboratori d’Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain); Keller, Jürg [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia); Brillas, Enric [Laboratori d’Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain); Radjenovic, Jelena, E-mail: j.radjenovic@awmc.uq.edu.au [Advanced Water Management Centre, The University of Queensland, Level 4, Gehrmann Bld. (60), St Lucia, QLD 072 (Australia)

    2015-02-11

    Graphical abstract: - Highlights: • Mineralization of secondary effluent by anodic oxidation with BDD anode. • Complete removal of 29 pharmaceuticals and pesticides at trace level concentrations. • Organochlorine and organobromine byproducts were formed at low μM concentrations. • Chlorine species evolution assessed to evaluate the anodic oxidation applicability. - Abstract: Electrochemical advanced oxidation processes (EAOPs) have been widely investigated as promising technologies to remove trace organic contaminants from water, but have rarely been used for the treatment of real waste streams. Anodic oxidation with a boron-doped diamond (BDD) anode was applied for the treatment of secondary effluent from a municipal sewage treatment plant containing 29 target pharmaceuticals and pesticides. The effectiveness of the treatment was assessed from the contaminants decay, dissolved organic carbon and chemical oxygen demand removal. The effect of applied current and pH was evaluated. Almost complete mineralization of effluent organic matter and trace contaminants can be obtained by this EAOP primarily due to the action of hydroxyl radicals formed at the BDD surface. The oxidation of Cl{sup −} ions present in the wastewater at the BDD anode gave rise to active chlorine species (Cl{sub 2}/HClO/ClO{sup −}), which are competitive oxidizing agents yielding chloramines and organohalogen byproducts, quantified as adsorbable organic halogen. However, further anodic oxidation of HClO/ClO{sup −} species led to the production of ClO{sub 3}{sup −} and ClO{sub 4}{sup −} ions. The formation of these species hampers the application as a single-stage tertiary treatment, but posterior cathodic reduction of chlorate and perchlorate species may reduce the risks associated to their presence in the environment.

  10. Utilizing sediments from biological waste water treatment for spraying spoil banks

    Energy Technology Data Exchange (ETDEWEB)

    Bobrov, O G; Zaitsev, Yu S; Kessariiskii, Yu V

    1985-04-01

    Use of anaerobic sludge for prevention of spontaneous combustion of spoil banks consisting of coal and mine stones from underground coal mines and effects of sludge treatment on soil properties which influence spoil bank reclamation are discussed. Sludge from water treatment rich in organic matter (50 to 60%), nitrogen (2 to 5%), phosphorus anhydride (up to 2%), calcium oxide (up to 5%) and humus was used in the Donbass. A spoil bank consisted of sedimentary rocks (sandstones, limestones, shales, clays, mudstone) and coal (size 0 to 200 mm). Coal content ranged from 7-13%, sulfur content amounted to about 5%. Content of coal, sulfur and timber exceeded 20%. The spoil bank was treated with sludge suspension in water. Evaluations showed that the sludge treatment improved soil properties which influenced spoil bank reclamation. Humus content increased 7 to 16 times, content of nitrogen trioxide and phosphorus anhydride increased 10 to 50 times. Chemical activity of rocks forming the spoil bank declined 20 to 25%. Hazards of coal spontaneous combustion decreased. The results of investigations are shown in a table.

  11. Role of a Water Network around the Mn4CaO5 Cluster in Photosynthetic Water Oxidation: A Fourier Transform Infrared Spectroscopy and Quantum Mechanics/Molecular Mechanics Calculation Study.

    Science.gov (United States)

    Nakamura, Shin; Ota, Kai; Shibuya, Yuichi; Noguchi, Takumi

    2016-01-26

    Photosynthetic water oxidation takes place at the Mn4CaO5 cluster in photosystem II. Around the Mn4CaO5 cluster, a hydrogen bond network is formed by several water molecules, including four water ligands. To clarify the role of this water network in the mechanism of water oxidation, we investigated the effects of the removal of Ca(2+) and substitution with metal ions on the vibrations of water molecules coupled to the Mn4CaO5 cluster by means of Fourier transform infrared (FTIR) difference spectroscopy and quantum mechanics/molecular mechanics (QM/MM) calculations. The OH stretching vibrations of nine water molecules forming a network between D1-D61 and YZ were calculated using the QM/MM method. On the the calculated normal modes, a broad positive feature at 3200-2500 cm(-1) in an S2-minus-S1 FTIR spectrum was attributed to the vibrations of strongly hydrogen-bonded OH bonds of water involving the vibrations of water ligands to a Mn ion and the in-phase coupled vibration of a water network connected to YZ, while bands in the 3700-3500 cm(-1) region were assigned to the coupled vibrations of weakly hydrogen-bonded OH bonds of water. All the water bands were lost upon Ca(2+) depletion and Ba(2+) substitution, which inhibit the S2 → S3 transition, indicating that a solid water network was broken by these treatments. By contrast, Sr(2+) substitution slightly altered the water bands around 3600 cm(-1), reflecting minor modification in water interactions, consistent with the retention of water oxidation activity with a decreased efficiency. These results suggest that the water network around the Mn4CaO5 cluster plays an essential role in the water oxidation mechanism particularly in a concerted process of proton transfer and water insertion during the S2 → S3 transition.

  12. Selective oxidation of organic compounds in waste water by ozone-based oxidation processes

    NARCIS (Netherlands)

    Boncz, M.A.

    2002-01-01

    For many different types of waste water, treatment systems have been implemented in the past decades. Waste water treatment is usually performed by biological processes, either aerobic or anaerobic, complemented with physical / chemical post treatment techniques.

  13. The effectiveness of water-treatment systems for arsenic used in 11 homes in Southwestern and Central Ohio, 2013

    Science.gov (United States)

    Thomas, Mary Ann; Ekberg, Mike

    2016-02-23

    In 2013, the U.S. Geological Survey and the Miami Conservancy District investigated the effectiveness of methods used to remove arsenic from drinking water at 11 homes in southwestern and central Ohio. The untreated (raw) ground-water had arsenic concentrations of 7.7–382 micrograms per liter (µg/L), and the median concentration was 30 µg/L. The pH was neutral to slightly alkaline, and redox conditions were strongly reducing, as indicated by high concentrations of iron. The predominant arsenic species was arsenite (As3+), which is difficult to treat because it exists in water as an uncharged compound (H3AsO3).The water-treatment systems included (1) seven single-tap reverse-osmosis systems, (2) two whole-house oxidation/filtration systems, and (3) two systems that included wholehouse anion exchange and single-tap reverse osmosis. All but one system included pretreatment by a water softener, and two systems included preoxidation to convert arsenite (As3+) to arsenate (As5+) before treatment by anion exchange.None of the treatment systems removed all of the arsenic from the drinking water. About one-half of the systems decreased the arsenic concentration to less than the maximum contamination level of 10 µg/L. The effectiveness of the systems varied widely; the percentage of arsenic removed ranged from 2 to 90 percent, and the median was 65 percent.At some sites, the low effectiveness of arsenic removal may have been related to system maintenance and(or) operation issues. At two sites, homeowners acknowledged that the treatment systems had not been maintained for several years. At two other sites, the treatment systems were being maintained, but the water-quality data indicated that one of the components was not working, unbeknownst to the homeowner. EPA research at a small number of sites in Ohio indicated that operation and maintenance of some arsenic-treatment systems was not always simple.Another factor that affected system effectiveness was the quality of

  14. Low-temperature conversion of ammonia to nitrogen in water with ozone over composite metal oxide catalyst.

    Science.gov (United States)

    Chen, Yunnen; Wu, Ye; Liu, Chen; Guo, Lin; Nie, Jinxia; Chen, Yu; Qiu, Tingsheng

    2018-04-01

    As one of the most important water pollutants, ammonia nitrogen emissions have increased year by year, which has attracted people's attention. Catalytic ozonation technology, which involves production of ·OH radical with strong oxidation ability, is widely used in the treatment of organic-containing wastewater. In this work, MgO-Co 3 O 4 composite metal oxide catalysts prepared with different fabrication conditions have been systematically evaluated and compared in the catalytic ozonation of ammonia (50mg/L) in water. In terms of high catalytic activity in ammonia decomposition and high selectivity for gaseous nitrogen, the catalyst with MgO-Co 3 O 4 molar ratio 8:2, calcined at 500°C for 3hr, was the best one among the catalysts we tested, with an ammonia nitrogen removal rate of 85.2% and gaseous nitrogen selectivity of 44.8%. In addition, the reaction mechanism of ozonation oxidative decomposition of ammonia nitrogen in water with the metal oxide catalysts was discussed. Moreover, the effect of coexisting anions on the degradation of ammonia was studied, finding that SO 4 2- and HCO 3 - could inhibit the catalytic activity while CO 3 2- and Br - could promote it. The presence of coexisting cations had very little effect on the catalytic ozonation of ammonia nitrogen. After five successive reuses, the catalyst remained stable in the catalytic ozonation of ammonia. Copyright © 2017. Published by Elsevier B.V.

  15. Iron oxidation kinetics and phosphate immobilization along the flow-path from groundwater into surface water

    Science.gov (United States)

    van der Grift, B.; Rozemeijer, J. C.; Griffioen, J.; van der Velde, Y.

    2014-11-01

    The retention of phosphorus in surface waters through co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and P immobilization along the flow-path from groundwater into surface water in an agricultural experimental catchment of a small lowland river. We physically separated tube drain effluent from groundwater discharge before it entered a ditch in an agricultural field. Through continuous discharge measurements and weekly water quality sampling of groundwater, tube drain water, exfiltrated groundwater, and surface water, we investigated Fe(II) oxidation kinetics and P immobilization processes. The oxidation rate inferred from our field measurements closely agreed with the general rate law for abiotic oxidation of Fe(II) by O2. Seasonal changes in climatic conditions affected the Fe(II) oxidation process. Lower pH and lower temperatures in winter (compared to summer) resulted in low Fe oxidation rates. After exfiltration to the surface water, it took a couple of days to more than a week before complete oxidation of Fe(II) is reached. In summer time, Fe oxidation rates were much higher. The Fe concentrations in the exfiltrated groundwater were low, indicating that dissolved Fe(II) is completely oxidized prior to inflow into a ditch. While the Fe oxidation rates reduce drastically from summer to winter, P concentrations remained high in the groundwater and an order of magnitude lower in the surface water throughout the year. This study shows very fast immobilization of dissolved P during the initial stage of the Fe(II) oxidation process which results in P-depleted water before Fe(II) is completely depleted. This cannot be explained by surface complexation of phosphate to freshly formed Fe-oxyhydroxides but indicates the formation of Fe(III)-phosphate precipitates. The formation of Fe(III)-phosphates at redox gradients

  16. Chlorination of bromide-containing waters: Enhanced bromate formation in the presence ofsynthetic metal oxides and deposits formed indrinking water distribution systems

    KAUST Repository

    Liu, Chao; von Gunten, Urs; Croue, Jean-Philippe

    2013-01-01

    Bromate formation from the reaction between chlorine and bromide in homogeneous solution is a slow process. The present study investigated metal oxides enhanced bromate formation during chlorination of bromide-containing waters. Selected metal oxides enhanced the decay of hypobromous acid (HOBr), a requisite intermediate during the oxidation of bromide to bromate, via (i) disproportionation to bromate in the presence of nickel oxide (NiO) and cupric oxide (CuO), (ii) oxidation of a metal to a higher valence state in the presence of cuprous oxide (Cu2O) and (iii) oxygen formation by NiO and CuO. Goethite (α-FeOOH) did not enhance either of these pathways. Non-charged species of metal oxides seem to be responsible for the catalytic disproportionation which shows its highest rate in the pH range near the pKa of HOBr. Due to the ability to catalyze HOBr disproportionation, bromate was formed during chlorination of bromide-containing waters in the presence of CuO and NiO, whereas no bromate was detected in the presence of Cu2O and α-FeOOH for analogous conditions. The inhibition ability of coexisting anions on bromate formation at pH 8.6 follows the sequence of phosphate>>sulfate>bicarbonate/carbonate. A black deposit in a water pipe harvested from a drinking water distribution system exerted significant residual oxidant decay and bromate formation during chlorination of bromide-containing waters. Energy dispersive spectroscopy (EDS) analyses showed that the black deposit contained copper (14%, atomic percentage) and nickel (1.8%, atomic percentage). Cupric oxide was further confirmed by X-ray diffraction (XRD). These results indicate that bromate formation may be of concern during chlorination of bromide-containing waters in distribution systems containing CuO and/or NiO. © 2013 Elsevier Ltd.

  17. Chlorination of bromide-containing waters: Enhanced bromate formation in the presence ofsynthetic metal oxides and deposits formed indrinking water distribution systems

    KAUST Repository

    Liu, Chao

    2013-09-01

    Bromate formation from the reaction between chlorine and bromide in homogeneous solution is a slow process. The present study investigated metal oxides enhanced bromate formation during chlorination of bromide-containing waters. Selected metal oxides enhanced the decay of hypobromous acid (HOBr), a requisite intermediate during the oxidation of bromide to bromate, via (i) disproportionation to bromate in the presence of nickel oxide (NiO) and cupric oxide (CuO), (ii) oxidation of a metal to a higher valence state in the presence of cuprous oxide (Cu2O) and (iii) oxygen formation by NiO and CuO. Goethite (α-FeOOH) did not enhance either of these pathways. Non-charged species of metal oxides seem to be responsible for the catalytic disproportionation which shows its highest rate in the pH range near the pKa of HOBr. Due to the ability to catalyze HOBr disproportionation, bromate was formed during chlorination of bromide-containing waters in the presence of CuO and NiO, whereas no bromate was detected in the presence of Cu2O and α-FeOOH for analogous conditions. The inhibition ability of coexisting anions on bromate formation at pH 8.6 follows the sequence of phosphate>>sulfate>bicarbonate/carbonate. A black deposit in a water pipe harvested from a drinking water distribution system exerted significant residual oxidant decay and bromate formation during chlorination of bromide-containing waters. Energy dispersive spectroscopy (EDS) analyses showed that the black deposit contained copper (14%, atomic percentage) and nickel (1.8%, atomic percentage). Cupric oxide was further confirmed by X-ray diffraction (XRD). These results indicate that bromate formation may be of concern during chlorination of bromide-containing waters in distribution systems containing CuO and/or NiO. © 2013 Elsevier Ltd.

  18. The anti-aging and anti-oxidation effects of tea water extract in Caenorhabditis elegans.

    Science.gov (United States)

    Fei, Tianyi; Fei, Jian; Huang, Fang; Xie, Tianpei; Xu, Jifeng; Zhou, Yi; Yang, Ping

    2017-10-15

    Tea includes puer tea, black tea, green tea and many others. By using model organism Caenorhabditis elegans, the anti-aging and anti-oxidation effects of tea water extract were systemically examined in this study. We found that water extract of puer tea, black tea and green tea all increased the lifespan of worms, postponed Aβ-induced progressive paralysis in Alzheimer's disease transgenic worms, and improved the tolerance of worms to the oxidative stress induced by heavy metal Cr 6+ . Moreover, the anti-oxidation effects of tea water extract at low concentration were different among 4 kinds of brands of green tea. The underlying mechanisms were further explored using genetically manipulated-mutant worms. The anti-oxidative stress effects of green tea water extract depend on the dietary restriction and germline signaling pathways, but not the FOXO and mitochondrial respiratory chain signals. Therefore, tea water extract provides benefits of anti-aging, anti-AD and anti-oxidation. Copyright © 2017. Published by Elsevier Inc.

  19. Calcium manganese(IV) oxides: biomimetic and efficient catalysts for water oxidation.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Pashaei, Babak; Nayeri, Sara

    2012-04-28

    CaMnO(3) and Ca(2)Mn(3)O(8) were synthesized and characterized by SEM, XRD, FTIR and BET. Both oxides showed oxygen evolution activity in the presence of oxone, cerium(IV) ammonium nitrate and H(2)O(2). Oxygen evolution from water during irradiation with visible light (λ > 400 nm) was also observed upon adding these manganese oxides to an aqueous solution containing tris(2,2'-bipyridyl) ruthenium(II), as photosensitizer, and chloro pentaammine cobalt(III) chloride, as electron acceptor, in an acetate buffer. The amounts of dissolved manganese and calcium from CaMnO(3) and Ca(2)Mn(3)O(8) in the oxygen evolving reactions were reported and compared with other (calcium) manganese oxides. Proposed mechanisms of oxygen evolution and proposed roles for the calcium ions are also considered. This journal is © The Royal Society of Chemistry 2012

  20. HANDBOOK ON ADVANCED PHOTOCHEMICAL OXIDATION ...

    Science.gov (United States)

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

  1. Arsenic adsorption in pre-treatment natural zeolite with magnesium oxides; Adsorcion de arsenico en zeolita natural pretratada con oxidos de magnesio

    Energy Technology Data Exchange (ETDEWEB)

    Mejia Z, F. [Universidad Autonoma de Baja California, Instituto de Ingenieria, Blvd. Benito Juarez s/n, 21900 Mexicali, Baja California (Mexico); Valenzuela G, J. L.; Aguayo S, S.; Meza F, D., E-mail: fleridam@iq.uson.m [Universidad de Sonora, Departamentos de Geologia e Ingenieria Quimica y Metalurgia, Blvd. Luis Encinas y Rosales s/n, Col. Centro, 83000 Hermosillo, Sonora (Mexico)

    2009-07-01

    A methodology was developed to modify a natural zeolite (chabazite) with magnesium oxide in order to remove arsenic (As{sup +5}) from water for human consumption. It is proposed a magnesium oxide while regarded as an efficient adsorbent for removing metals in water. X-ray diffraction analyses show significant changes in the chabazite due to the presence of oxides and amorphous hydroxides incorporated during the pre-treatment. Experimental design results show an efficiency greater than 90% of As{sup +5} adsorbed in five minutes. The results indicate that the most significant variables affecting the adsorption of As{sup +5} are the initial concentration of As and the solid/liquid ratio. Experimental data fitted better to Freundlich isotherm with a 20.17 mg/g adsorption capability. (Author)

  2. Pretreatment of algae-laden and manganese-containing waters by oxidation-assisted coagulation: Effects of oxidation on algal cell viability and manganese precipitation.

    Science.gov (United States)

    Lin, Jr-Lin; Hua, Lap-Cuong; Wu, Yuting; Huang, Chihpin

    2016-02-01

    Preoxidation is manipulated to improve performance of algae and soluble manganese (Mn) removal by coagulation-sedimentation for water treatment plants (WTPs) when large amount of soluble Mn presents in algae-laden waters. This study aimed to investigate the effects of preoxidation on the performance of coagulation-sedimentation for the simultaneous removal of algae and soluble Mn, including ionic and complexed Mn. NaOCl, ClO2, and KMnO4 were used to pretreat such algae-laden and Mn containing waters. The variation of algal cell viability, residual cell counts, and concentrations of Mn species prior to and after coagulation-sedimentation step were investigated. Results show that NaOCl dosing was effective in reducing the viability of algae, but precipitated little Mn. ClO2 dosing had a strongest ability to lower algae viability and oxidize ionic and complexed soluble Mn, where KMnO4 dosing oxidized ionic and complexed Mn instead of reducing the viability of cells. Preoxidation by NaOCl only improved the algae removal by sedimentation, whereas most of soluble Mn still remained. On the other hand, ClO2 preoxidation substantially improved the performance of coagulation-sedimentation for simultaneous removal of algae and soluble Mn. Furthermore, KMnO4 preoxidation did improve the removal of algae by sedimentation, but left significant residual Mn in the supernatant. Images from FlowCAM showed changes in aspect ratio (AR) and transparency of algae-Mn flocs during oxidation-assisted coagulation, and indicates that an effective oxidation can improve the removal of most compact algae-Mn flocs by sedimentation. It suggests that an effective preoxidation for reducing algal cell viability and the concentration of soluble Mn is a crucial step for upgrading the performance of coagulation-sedimentation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Novel Americium Treatment Process for Surface Water and Dust Suppression Water

    International Nuclear Information System (INIS)

    Tiepel, E.W.; Pigeon, P.; Nesta, S.; Anderson, J.

    2006-01-01

    The Rocky Flats Environmental Technology Site (RFETS), a former nuclear weapons production plant, has been remediated under CERCLA and decommissioned to become a National Wildlife Refuge. The site conducted this cleanup effort under the Rocky Flats Cleanup Agreement (RFCA) that established limits for the discharge of surface and process waters from the site. At the end of 2004, while a number of process buildings were undergoing decommissioning, routine monitoring of a discharge pond (Pond A-4) containing approximately 28 million gallons of water was discovered to have been contaminated with a trace amount of Americium-241 (Am-241). While the amount of Am-241 in the pond waters was very low (0.5 - 0.7 pCi/l), it was above the established Colorado stream standard of 0.15 pCi/l for release to off site drainage waters. The rapid successful treatment of these waters to the regulatory limit was important to the site for two reasons. The first was that the pond was approaching its hold-up limit. Without rapid treatment and release of the Pond A-4 water, typical spring run-off would require water management actions to other drainages onsite or a mass shuttling of water for disposal. The second reason was that this type of contaminated water had not been treated to the stringent stream standard at Rocky Flats before. Technical challenges in treatment could translate to impacts on water and secondary waste management, and ultimately, cost impacts. All of the technical challenges and specific site criteria led to the conclusion that a different approach to the treatment of this problem was necessary and a crash treatability program to identify applicable treatment techniques was undertaken. The goal of this program was to develop treatment options that could be implemented very quickly and would result in the generation of no high volume secondary waste that would be costly to dispose. A novel chemical treatment system was developed and implemented at the RFETS to treat Am

  4. ADVANCED OXIDATION PROCESS TECHNOLOGY (ULTRAVIOLET RADIATION/OZONE TREATMENT) FOR REMOVAL OF METHYL TERTIARY BUTYL ETHER (MTBE) IN GROUND WATER SUPPLIES.

    Science.gov (United States)

    U.S. EPA’s Office of Research and Development in Cincinnati, Ohio has been testing and evaluating MTBE removal in dechlorinated tap water using three oxidant combinations: hydrogen peroxide/ozone, ultraviolet irradiation (UV)/ozone, and UV/ozone/hydrogen peroxide. Pilot-scale st...

  5. New aeration systems for higher efficiency in mine water treatment in the Lausitz region; Einsatz neuer Belueftungssysteme zur Effizienzsteigerung bei der Grubenwasserbehandlung in der Lausitz

    Energy Technology Data Exchange (ETDEWEB)

    Janneck, E.; Glombitza, F. [G.E.O.S. Freiberg Ingenieurgesellschaft mbH, Freiberg (Germany); Schlee, K.; Arnold, I. [Vattenfall Europe Mining AG, Cottbus (Germany)

    2006-07-01

    The article presents experiences and results of the application of new aerator-systems in the mine water treatment. The processes of ferrous iron oxidation and sludge removal became more stable and efficiently by the application of the aerators. For the first time, spiral aerators were used in the Lower Lusatia lignite mining district to clean ferrous iron containing mine water. These devices lead to an enhanced iron oxidation rate under the existing conditions, where the oxygen diffusion is the rate determining step. Furthermore, the application caused increased throughput, optimal lime utilisation and better sludge thickening, which led to a higher efficiency of the mine water treatment. (orig.)

  6. Energy use and carbon footprint for potable water and wastewater treatment

    Directory of Open Access Journals (Sweden)

    Presura Elena

    2017-07-01

    Full Text Available Wastewater treatment plants (WWTPs and drinking water treatment plants (DWTPs are sources of emissions of greenhouse gases (GHGs, such as carbon dioxide (CO2, nitrous oxide (N2O and methane (CH4. Carbon dioxide emissions have a big contribution to climate change. In general they come from burning fossil fuels to generate the electricity necessary for operating the treatment processes. The demand of energy depends on the treatment processes, but also on the quality of water source or wastewater influent. Water companies have to continuously supply safe drinking water to population and to treat and discharge wastewater according to regulations at a cost as low as possible. In Romania reporting of GHGs is not mandatory for water companies. Evaluation of GHG emissions from water industry have become a subject of great interest because of concern regarding climate change. Research and regulation have been conducted by different authors based on a regional basis. This paper proposes to estimate and compare the carbon emissions resulting from power consumption of Constanta South WWTP and PALAS Constanta DWTP. The energy supplier is different for these plants. In order to calculate the carbon emissions the amount of specific CO2 emissions is determined. The contribution of each primary source to produce the amount of electricity which is consumed is taken into account. WWTP has high power consumption in biological processes, because there are the aeration tanks, the sewage pumping station and the equipment for sludge. DWTP has high power consumption because of the pumping equipment used for raw water abstraction from deep wells and those for drinking water distribution to consumers. In order to identify, sort and display possible causes of the high power consumption of WWTP, Ishikawa chart is used. Through its configuration, the diagram allows highlighting and prioritizing the causes which generate this effect. Some management options are presented in

  7. Effect of sulfite treatment on total antioxidant capacity, total oxidant status, lipid hydroperoxide, and total free sulfydryl groups contents in normal and sulfite oxidase-deficient rat plasma.

    Science.gov (United States)

    Herken, Emine Nur; Kocamaz, Erdogan; Erel, Ozcan; Celik, Hakim; Kucukatay, Vural

    2009-08-01

    Sulfites, which are commonly used as preservatives, are continuously formed in the body during the metabolism of sulfur-containing amino acids. Sulfite oxidase (SOX) is an essential enzyme in the pathway of the oxidative degradation of sulfite to sulfate protecting cells from sulfite toxicity. This article investigated the effect of sulfite on total antioxidant capacity (TAC), total oxidant status, lipid hydroperoxide (LOOH), and total free sulfydryl groups (-SH) levels in normal and SOX-deficient male albino rat plasma. For this purpose, rats were divided into four groups: control, sulfite-treated, SOX-deficient, and sulfite-treated SOX-deficient groups. SOX deficiency was established by feeding rats a low molybdenum diet and adding to their drinking water 200 ppm tungsten. Sulfite (70 mg/kg) was administered to the animals via their drinking water. SOX deficiency together with sulfite treatment caused a significant increase in the plasma LOOH and total oxidant status levels. -SH content of rat plasma significantly decreased by both sulfite treatment and SOX deficiency compared to the control. There was also a significant decrease in plasma TAC level by sulfite treatment. In conclusion, sulfite treatment affects the antioxidant/oxidant balance of the plasma cells of the rats toward oxidants in SOX-deficient groups.

  8. Separation of tritiated water using graphene oxide membrane

    Energy Technology Data Exchange (ETDEWEB)

    Sevigny, Gary J. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Motkuri, Radha K. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Gotthold, David W. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Fifield, Leonard S. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Frost, Anthony P. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Bratton, Wesley [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

    2015-06-28

    In future nuclear fuel reprocessing plants and possibly for nuclear power plants, the cleanup of tritiated water will be needed for hundreds of thousands of gallons of water with low activities of tritium. This cleanup concept utilizes graphene oxide laminar membranes (GOx) for the separation of low-concentration (10-3-10 µCi/g) tritiated water to create water that can be released to the environment and a much smaller waste stream with higher tritium concentrations. Graphene oxide membranes consist of hierarchically stacked, overlapping molecular layers and represent a new class of materials. A permeation rate test was performed with a 2-µm-thick cast Asbury membrane using mixed gas permeability testing with zero air (highly purified atmosphere) and with air humidified with either H2O or D2O to a nominal 50% relative humidity. The membrane permeability for both H2O and D2O was high with N2 and O2 at the system measurement limit. The membrane water permeation rate was compared to a Nafion® membrane and the GOx permeation was approximately twice as high at room temperature. The H2O vapor permeation rate was 5.9 × 102 cc/m2/min (1.2 × 10-6 g/min-cm2), which is typical for graphene oxide membranes. To demonstrate the feasibility of such isotopic water separation through GOX laminar membranes, an experimental setup was constructed to use pressure-driven separation by heating the isotopic water mixture at one side of the membrane to create steam while cooling the other side. Several membranes were tested and were prepared using different starting materials and by different pretreatment methods. The average separation result was 0.8 for deuterium and 0.6 for tritium. Higher or lower temperatures may also improve separation efficiency but neither has been tested yet. A rough estimate of cost compared to current technology was also included as an indication of potential viability of the process. The relative process costs were based on the rough size of facility to

  9. Application of advanced oxidative process in treatment radioactive waste

    International Nuclear Information System (INIS)

    Kim, Catia; Sakata, Solange K.; Ferreira, Rafael V.P.; Marumo, Julio T.

    2009-01-01

    The ion exchange resin is used in the water purification system in both nuclear research and power reactors. Combined with active carbon, the resin removes dissolved elements from water when the nuclear reactor is operating. After its consumption, it becomes a special type of radioactive waste. The usual treatment to this type of waste is the immobilization with Portland cement, which is simple and low cost. However, its low capacity of immobilization and the increase volume of waste have been the challenges. The development of new technologies capable of destroying this waste completely by increasing its solidification is the main target due to the possibility of both volume and cost reduction. The objective of this work was to evaluate ion exchange resin degradation by Advanced Oxidative Process using Fenton's Reagent (H 2 O 2 / Fe +2 ) in different concentration and temperatures. One advantage of this process is that all additional organic compounds or inorganic solids produced are oxidized easily. The degradation experiments were conducted with IRA-400 resin and Fenton's Reagents, varying the H 2O 2 concentration (30% e 50%) and heat temperature (25, 60 and 100 deg C). The resin degradation was confirmed by the presence of BaCO 3 as a white precipitate resulting from the reaction between the Ba(OH) 2 and the CO 2 from the resin degradation. All experiments run in duplicate. Higher degradation was observed with Fenton's Reagent (Fe +2 /H 2 O 2 30%) at 100 deg C after 2 hours. (author)

  10. Photoanodic Hybrid Semiconductor–Molecular Heterojunction for Solar Water Oxidation

    KAUST Repository

    Joya, Khurram Saleem

    2015-06-29

    Inorganic photo-responsive semiconducting materials have been employed in photoelectrochemical(PEC) water oxidation devicesin pursuit of solar to fuel conversion.[1]The reaction kinetics in semiconductors is limited by poor contact at the interfaces, and charge transfer is impeded by surface defects and the grain boundaries.[2]It has shown that successful surface functionalization of the photo-responsive semiconducting materials with co-catalysts can maximize the charge separation, hole delivery and its effective consumption, and enhances the efficiency and performane of the PEC based water oxidation assembly.[3]We present here unique modification of photoanodic hematite (α-Fe2O3) and bismuth vanadate (BiVO4) with molecular co-catalysts for enhanced photoelectrochemical water oxidation (Figure 1). These hybrid inorganic–organometallic heterojunctions manifest impressive cathodic shifts in the onset potentials, and the photocurrent densities have been enhanced by > 90% at all potentials relative to uncatalyzed α-Fe2O3 or BiVO4, and other catalyst-semiconductor based heterojunctions.This is a novel development in the solar to fuel conversion field, and is crucially important for designing a tandem device where light interfere very little with the catalyst layer on top of semiconducting light absorber.

  11. New Ir Bis-Carbonyl Precursor for Water Oxidation Catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Daria L. [Department of Chemistry, Yale University, 225; Beltrán-Suito, Rodrigo [Department of Chemistry, Yale University, 225; Thomsen, Julianne M. [Department of Chemistry, Yale University, 225; Hashmi, Sara M. [Department of Chemical and Environmental; Materna, Kelly L. [Department of Chemistry, Yale University, 225; Sheehan, Stafford W. [Catalytic Innovations LLC, 70 Crandall; Mercado, Brandon Q. [Department of Chemistry, Yale University, 225; Brudvig, Gary W. [Department of Chemistry, Yale University, 225; Crabtree, Robert H. [Department of Chemistry, Yale University, 225

    2016-02-05

    This paper introduces IrI(CO)2(pyalc) (pyalc = (2-pyridyl)-2-propanoate) as an atom-efficient precursor for Ir-based homogeneous oxidation catalysis. This compound was chosen to simplify analysis of the water oxidation catalyst species formed by the previously reported Cp*IrIII(pyalc)OH water oxidation precatalyst. Here, we present a comparative study on the chemical and catalytic properties of these two precursors. Previous studies show that oxidative activation of Cp*Ir-based precursors with NaIO4 results in formation of a blue IrIV species. This activation is concomitant with the loss of the placeholder Cp* ligand which oxidatively degrades to form acetic acid, iodate, and other obligatory byproducts. The activation process requires substantial amounts of primary oxidant, and the degradation products complicate analysis of the resulting IrIV species. The species formed from oxidation of the Ir(CO)2(pyalc) precursor, on the other hand, lacks these degradation products (the CO ligands are easily lost upon oxidation) which allows for more detailed examination of the resulting Ir(pyalc) active species both catalytically and spectroscopically, although complete structural analysis is still elusive. Once Ir(CO)2(pyalc) is activated, the system requires acetic acid or acetate to prevent the formation of nanoparticles. Investigation of the activated bis-carbonyl complex also suggests several Ir(pyalc) isomers may exist in solution. By 1H NMR, activated Ir(CO)2(pyalc) has fewer isomers than activated Cp*Ir complexes, allowing for advanced characterization. Future research in this direction is expected to contribute to a better structural understanding of the active species. A diol crystallization agent was needed for the structure determination of 3.

  12. Treatment of statin compounds by advanced oxidation processes: Kinetic considerations and destruction mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Razavi, Behnaz, E-mail: brazavi@uci.ed [Urban Water Research Center, Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, CA 92697-2175 (United States); Song Weihua, E-mail: wsong@uci.ed [Urban Water Research Center, Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, CA 92697-2175 (United States); Santoke, Hanoz, E-mail: hsantoke@uci.ed [Urban Water Research Center, Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, CA 92697-2175 (United States); Cooper, William J., E-mail: wcooper@uci.ed [Urban Water Research Center, Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, CA 92697-2175 (United States)

    2011-03-15

    This study examined the use of advanced oxidation/reduction processes (AO/RPs) for the destruction of cholesterol lowering statin pharmaceuticals. AO/RPs which utilize the oxidizing hydroxyl radical ({sup {center_dot}O}H) and reducing aqueous electron (e{sup -}{sub aq}), to degrade chemical contaminants are alternatives to traditional water treatment methods, and are alternatives as water reuse becomes more generally implemented. Four major statin pharmaceuticals, fluvastatin, lovastatin, pravastatin and simvastatin, were studied, and the absolute bimolecular reaction rate constants with {sup {center_dot}O}H determined, (6.96{+-}0.16)x10{sup 9}, (2.92{+-}0.06)x10{sup 9}, (4.16{+-}0.13)x10{sup 9}, and (3.13{+-}0.15)x10{sup 9} M{sup -1} s{sup -1}, and for e{sup -}{sub aq} (2.31{+-}0.06)x10{sup 9}, (0.45{+-}0.01)x10{sup 9}, (1.26{+-}0.01)x10{sup 9}, and (0.69{+-}0.02)x10{sup 9} M{sup -1} s{sup -1}, respectively. To provide additional information on the radicals formed upon oxidation, transient spectra were measured and the overall reaction efficiency determined. Radical-based destruction mechanisms for destruction of the statins are proposed based on the LC-MS determination of the stable reaction by-products formed using {sup 137}Cs {gamma}-irradiation of statin solutions. Knowing the reaction rates, reaction efficiencies and destruction mechanisms of these compounds is essential for the consideration of the use of advanced oxidation/reduction processes for the destruction of statins in aqueous systems.

  13. Advanced oxidation technologies : photocatalytic treatment of wastewater

    OpenAIRE

    Chen, J.

    1997-01-01

    7.1. Summary and conclusions

    The last two decennia have shown a growing interest in the photocatalytic treatment of wastewater, and more and more research has been carried out into the various aspects of photocatalysis, varying from highly fundamental aspects to practical application. However, despite all this research, there is still much to investigate. Suggested photocatalytic mechanisms, such as those for oxidation by hydroxyl radicals and for oxidation at the surface of photocata...

  14. SAFIRA project B.3.3: in-situ-treatment of contaminated ground water by catalytic oxidation. Final report; Sanierungsforschung in regional kontaminierten Aquiferen (SAFIRA). Projekt B.3.3: In situ-Behandlung von kontaminierten Grundwaessern durch katalytische Oxidation. Teilvorhaben 1: Untersuchungen im Labormassstab. Teilvorhaben 2: Tests in der bench-scale-Anlage und Teilvorhaben 3: Die Erprobung in der Pilotanlage am Modellstandort. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, J.; Haentzschel, D.; Freier, U.; Wecks, M.

    2003-06-27

    A new technology for treatment of contaminated ground water was developed. In this process heterogeneous catalysts (full metal catalyst, mixed oxide catalyst or iron-containing zeolites) in combination with hydrogen peroxide are used. In the reactor catalytic oxidation and aerob biological degradation occur simultaneously. A complete degradation of chlorobenzene was observed in a bench-scale-equipment (2 liter) and also in the pilot plant at the model site located in Bitterfeld (30 liter reactor). The technology can be applied to the ground and waste water treatment. (orig.) [German] Fuer die Behandlung von Grundwaessern, die mit organischen Schadstoffen belastet sind, wurde ein neuartiges Verfahren entwickelt. Bei der katalytischen Oxidation werden heterogene Katalysatoren in Form von Vollmetall-, Mischoxid- und Traegerkatalysatoren in Verbindung mit Wasserstoffperoxid als Oxidationsmittel eingesetzt. In den Katalysereaktoren laufen die heterogen-katalytische Oxidation und der aerob-biologische Abbau nebeneinander ab. Es werden synergistische Effekte erzielt. Mit dem Verfahren wurde in einer bench-scale-Angle (2 Liter) und in der Pilotanlage am Modellstandort in Bitterfeld (30 l Reaktor) der Schadstoff Chlorbenzol vollstaendig umgesetzt. Das Verfahren kann zur Grund- und Abwasserbehandlung eingesetzt werden. (orig.)

  15. Treatment of secondary effluent by sequential combination of photocatalytic oxidation with ceramic membrane filtration.

    Science.gov (United States)

    Song, Lili; Zhu, Bo; Jegatheesan, Veeriah; Gray, Stephen; Duke, Mikel; Muthukumaran, Shobha

    2018-02-01

    The aim of the present work was to experimentally evaluate an alternative advanced wastewater treatment system, which combines the action of photocatalytic oxidation with ceramic membrane filtration. Experiments were carried out using laboratory scale TiO 2 /UV photocatalytic reactor and tubular ceramic microfiltration (CMF) system to treat the secondary effluent (SE). A 100-nm pore size CMF membrane was investigated in cross flow mode under constant transmembrane pressure of 20 kPa. The results show that specific flux decline of CMF membrane with and without TiO 2 /UV photocatalytic treatment was 30 and 50%, respectively, after 60 min of filtration. Data evaluation revealed that the adsorption of organic compounds onto the TiO 2 particles was dependent on the pH of the suspension and was considerably higher at low pH. The liquid chromatography-organic carbon detector (LC-OCD) technique was used to characterise the dissolved organic matter (DOM) present in the SE and was monitored following photocatalysis and CMF. The results showed that there was no removal of biopolymers and slight removal of humics, building blocks and the other oxidation by-products after TiO 2 /UV photocatalytic treatment. This result suggested that the various ions present in the SE act as scavengers, which considerably decrease the efficiency of the photocatalytic oxidation reactions. On the other hand, the CMF was effective for removing 50% of biopolymers with no further removal of other organic components after photocatalytic treatment. Thus, the quantity of biopolymers in SE has an apparent correlation with the filterability of water samples in CMF.

  16. Organic Micropollutants Removal from Water by Oxidation and Other Processes:QSAR Models, Decision Support System and Hybrids of Processes

    KAUST Repository

    Sudhakaran, Sairam

    2013-08-01

    The presence of organic micropollutants (OMPs) in water is of great environmental concern. OMPs such as endocrine disruptors and certain pharmaceuticals have shown alarming effects on aquatic life. OMPs are included in the priority list of contaminants in several government directorate frameworks. The low levels of OMPs concentration (ng/L to μg/L) force the use of sophisticated analytical instruments. Although, the techniques to detect OMPs are progressing, the focus of current research is only on limited, important OMPs due to the high amount of time, cost and effort involved in analyzing them. Alternatively, quantitative structure activity relationship (QSAR) models help to screen processes and propose appropriate options without considerable experimental effort. QSAR models are well-established in regulatory bodies as a method to screen toxic chemicals. The goal of the present thesis was to develop QSAR models for OMPs removal by oxidation. Apart from the QSAR models, a decision support system (DSS) based on multi-criteria analysis (MCA) involving socio-economic-technical and sustainability aspects was developed. Also, hybrids of different water treatment processes were studied to propose a sustainable water treatment train for OMPs removal. In order to build the QSAR models, the ozone/hydroxyl radical rate constants or percent removals of the OMPs were compiled. Several software packages were used to 5 compute the chemical properties of OMPs and perform statistical analyses. For DSS, MCA was used since it allows the comparison of qualitative (non-monetary, non-metric) and quantitative criteria (e.g., costs). Quadrant plots were developed to study the hybrid of natural and advanced water treatment processes. The QSAR models satisfied both chemical and statistical criteria. The DSS resulted in natural treatment and ozonation as the preferred processes for OMPs removal. The QSAR models can be used as a screening tool for OMPs removal by oxidation. Moreover, the

  17. Delocalized organic pollutant destruction through a self-sustaining supercritical water oxidation process

    International Nuclear Information System (INIS)

    Lavric, E.D.; Weyten, H.; Ruyck, J. de; Plesu, V.; Lavric, V.

    2005-01-01

    Supercritical water oxidation (SCWO) is a recent development aiming at the destruction of organic pollutants present with low concentrations in waste waters. The present paper focuses on the process simulation of SCWO with emphasis on the proper modelling of supercritical thermodynamic conditions and on the possibility to make the SCWO process self-sufficient from the energetic viewpoint. Self-sufficiency may be of interest to encourage more delocalization of waste water treatment. The process of SCWO for dilute waste water (no more than 5 wt.%) is modelled through the ASPEN Plus copyright process simulator. Studies were made to search for energetic self-sufficiency conditions using various technologies for power production from the heat of reaction, like supercritical water expansion in a turbine, use of a closed Brayton cycle (CBC) and use of an organic Rankine cycle (ORC). The results obtained showed that the process is energetically self-sufficient using either a small supercritical turbine, or an ORC. In less restrictive conditions regarding the component efficiencies, the CBC, in theory, also leads to self-sufficiency, but from the analysis, it appears that this solution is less realistic

  18. Effect of thermal treatment conditions on properties of vanadium molybdenum oxide catalyst in acrolein oxidation reaction to acrylic acid

    International Nuclear Information System (INIS)

    Gorshkova, T.P.; Tarasova, D.V.; Olen'kova, I.P.; Andrushkevich, T.V.; Nikoro, T.A.

    1984-01-01

    The effect of thermal treatment conditions (temperature and gas medium) on properties of vanadium molybdenum oxide catalyst in acrolein oxidation reaction to acrylic acid is investigated. It is shown that active and selective catalysts are formed in the course of thermal decomposition of the drying product of ammonium metavanadate and paramolybdate under the conditions ensuring the vanadium ion reduction up to tetravalent state with conservation of molybdenum oxidation degree equal to 6. It is possible to realize it either by treatment of the catalyst calcinated in the air flow at 300 deg by the reaction mixture at the activation stage or by gas-reducer flow treatment at 280 deg. Thermal treatment in the reducing medium of the oxidized catalyst does not lead to complete regeneration of its properties

  19. Combined treatment of retting flax wastewater using Fenton oxidation and granular activated carbon

    Directory of Open Access Journals (Sweden)

    Sohair I. Abou-Elela

    2016-07-01

    Full Text Available The process of retting flax produces a huge amount of wastewater which is characterized with bad unpleasant smell and high concentration of organic materials. Treatment of such waste had always been difficult because of the presence of refractory organic pollutants such as lignin. In this study, treatment of retting wastewater was carried out using combined system of Fenton oxidation process followed by adsorption on granular activated carbon (GAC. The effects of operating condition on Fenton oxidation process such as hydrogen peroxide and iron concentration were investigated. In addition, kinetic study of the adsorption process was elaborated. The obtained results indicated that degradation of organic matters follows a pseudo-first order reaction with regression coefficient of 0.98. The kinetic model suggested that the rate of reaction was highly affected by the concentration of hydrogen peroxide. Moreover, the results indicated that the treatment module was very efficient in removing the organic and inorganic pollutants. The average percentage removal of chemical oxygen demand (COD, total suspended solid (TSS, oil, and grease was 98.60%, 86.60%, and 94.22% with residual values of 44, 20, and 5 mg/L, respectively. The treated effluent was complying with the National Regulatory Standards for wastewater discharge into surface water or reuse in the retting process.

  20. Cork boiling wastewater treatment and reuse through combination of advanced oxidation technologies.

    Science.gov (United States)

    Ponce-Robles, L; Miralles-Cuevas, S; Oller, I; Agüera, A; Trinidad-Lozano, M J; Yuste, F J; Malato, S

    2017-03-01

    Industrial preparation of cork consists of its immersion for approximately 1 hour in boiling water. The use of herbicides and pesticides in oak tree forests leads to absorption of these compounds by cork; thus, after boiling process, they are present in wastewater. Cork boiling wastewater shows low biodegradability and high acute toxicity involving partial inhibition of their biodegradation when conventional biological treatment is applied. In this work, a treatment line strategy based on the combination of advanced physicochemical technologies is proposed. The final objective is the reuse of wastewater in the cork boiling process; thus, reducing consumption of fresh water in the industrial process itself. Coagulation pre-treatment with 0.5 g/L of FeCl 3 attained the highest turbidity elimination (86 %) and 29 % of DOC elimination. Similar DOC removal was attained when using 1 g/L of ECOTAN BIO (selected for ozonation tests), accompanied of 64 % of turbidity removal. Ozonation treatments showed less efficiency in the complete oxidation of cork boiling wastewater, compared to solar photo-Fenton process, under the studied conditions. Nanofiltration system was successfully employed as a final purification step with the aim of obtaining a high-quality reusable permeate stream. Monitoring of unknown compounds by LC-QTOF-MS allowed the qualitative evaluation of the whole process. Acute and chronic toxicity as well as biodegradability assays were performed throughout the whole proposed treatment line.

  1. Microbial growth associated with granular activated carbon in a pilot water treatment facility.

    Science.gov (United States)

    Wilcox, D P; Chang, E; Dickson, K L; Johansson, K R

    1983-01-01

    The microbial dynamics associated with granular activated carbon (GAC) in a pilot water treatment plant were investigated over a period of 16 months. Microbial populations were monitored in the influent and effluent waters and on the GAC particles by means of total plate counts and ATP assays. Microbial populations between the influent and effluent waters of the GAC columns generally increased, indicating microbial growth. The dominant genera of microorganisms isolated from interstitial waters and GAC particles were Achromobacter, Acinetobacter, Aeromonas, Alcaligenes, Bacillus, Chromobacterium, Corynebacterium, Micrococcus, Microcyclus, Paracoccus, and Pseudomonas. Coliform bacteria were found in small numbers in the effluents from some of the GAC columns in the later months of the study. Oxidation of influent waters with ozone and maintenance of aerobic conditions on the GAC columns failed to appreciably enhance the microbial growth on GAC. PMID:6625567

  2. Influence of Adsorbed Water on the Oxygen Evolution Reaction on Oxides

    DEFF Research Database (Denmark)

    Siahrostami, Samira; Vojvodic, Aleksandra

    2015-01-01

    We study the interface between adsorbed water and stoichiometric, defect-free (110) rutile oxide surfaces of TiO2, RuO2, and IrO2 in order to understand how water influences the stabilities of the intermediates of the oxygen evolution reaction (OER). In our model the water is treated as explicitly...... molecules binding to bridging oxygens. The third chain interacts weakly and predominantly with the H2O molecules of the second layer, resembling bulk water. We find that the stability of the water layer close to the oxide surface is almost the same as the one found on flat metal surfaces, such as the Pt(111...... of RuO2 and IrO2, while it is increased by similar to 0.4 eV for TiO2....

  3. Understanding flocculation mechanism of graphene oxide for organic dyes from water: Experimental and molecular dynamics simulation

    Directory of Open Access Journals (Sweden)

    Jun Liu

    2015-11-01

    Full Text Available Flocculation treatment processes play an important role in water and wastewater pretreatment. Here we investigate experimentally and theoretically the possibility of using graphene oxide (GO as a flocculant to remove methylene blue (MB from water. Experimental results show that GO can remove almost all MB from aqueous solutions at its optimal dosages and molecular dynamics simulations indicate that MB cations quickly congregate around GO in water. Furthermore, PIXEL energy contribution analysis reveals that most of the strong interactions between GO and MB are of a van der Waals (London dispersion character. These results offer new insights for shedding light on the molecular mechanism of interaction between GO and organic pollutants.

  4. Behaviour of aqueous sulfamethizole solution and temperature effects in cold plasma oxidation treatment.

    Science.gov (United States)

    Sokolov, Alexander; Louhi-Kultanen, Marjatta

    2018-06-07

    The increase in volume and variety of pharmaceuticals found in natural water bodies has become an increasingly serious environmental problem. The implementation of cold plasma technology, specifically gas-phase pulsed corona discharge (PCD), for sulfamethizole abatement was studied in the present work. It was observed that sulfamethizole is easily oxidized by PCD. The flow rate and pH of the solution have no significant effect on the oxidation. Treatment at low pulse repetition frequency is preferable from the energy efficiency point of view but is more time-consuming. The maximum energy efficiency was around 120 g/kWh at half-life and around 50 g/kWh at the end of the treatment. Increasing the solution temperature from room temperature to 50 °C led to a significant reaction retardation of the process and decrease in energy efficiency. The pseudo-first order reaction rate constant (k 1 ) grows with increase in pulse repetition frequency and does not depend on pH. By contrast, decreasing frequency leads to a reduction of the second order reaction rate constant (k 2 ). At elevated temperature of 50 °C, the k 1 , k 2 values decrease 2 and 2.9 times at 50 pps and 500 pps respectively. Lower temperature of 10 °C had no effect on oxidation efficiency compared with room temperature.

  5. [Ultrasound induced the formation of nitric oxide and nitrosonium ions in water and aqueous solutions].

    Science.gov (United States)

    Stepuro, I I; Adamchuk, R I; Stepuro, V I

    2004-01-01

    Nitric oxide, nitrosonium ions, nitrites, and nitrates are formed in water saturated with air under the action of ultrasound. Nitrosonium ions react with water and hydrogen peroxide to form nitrites and nitrates in sonicated solution, correspondingly. Nitric oxide is practically completely released from sonicated water into the atmosphere and reacts with air oxygen, forming NOx compounds. The oxidation of nitric oxide in aqueous medium by hydroxyl radicals and dissolved oxygen is a minor route of the formation of nitrites and nitrates in ultrasonic field.

  6. Removal of NOM-constituents as characterized by LC-OCD and F-EEM during drinking water treatment

    KAUST Repository

    Baghoth, S. A.

    2011-11-01

    Natural organic matter (NOM) is of concern in drinking water because it causes adverse aesthetic qualities such as taste, odour, and colour; impedes the performance of treatment processes; and decreases the effectiveness of oxidants and disinfectants while contributing to undesirable disinfection by-products. The effective removal of NOM during drinking water treatment requires a good understanding of its character. Because of its heterogeneity, NOM characterization necessitates the use of multiple analytical techniques. In this study, NOM in water samples from two drinking water treatment trains was characterized using liquid chromatography with organic carbon detection (LC-OCD), and fluorescence excitation-emission matrices (F-EEMs) with parallel factor analysis (PARAFAC). These characterization methods indicate that the raw and treated waters are dominated by humic substances. The results show that whereas the coagulation process for both plants may be optimized for the removal of bulk DOC, it is not likewise optimized for the removal of specific NOM fractions. A five component PARAFAC model was developed for the F-EEMs, three of which are humic-like, while two are protein-like. These PARAFAC components and the LC-OCD fractions represented effective tools for the performance evaluation of the two water treatment plants in terms of the removal of NOM fractions. © IWA Publishing 2011.

  7. Estimation of Oxidation Kinetics and Oxide Scale Void Position of Ferritic-Martensitic Steels in Supercritical Water

    Directory of Open Access Journals (Sweden)

    Li Sun

    2017-01-01

    Full Text Available Exfoliation of oxide scales from high-temperature heating surfaces of power boilers threatened the safety of supercritical power generating units. According to available space model, the oxidation kinetics of two ferritic-martensitic steels are developed to predict in supercritical water at 400°C, 500°C, and 600°C. The iron diffusion coefficients in magnetite and Fe-Cr spinel are extrapolated from studies of Backhaus and Töpfer. According to Fe-Cr-O ternary phase diagram, oxygen partial pressure at the steel/Fe-Cr spinel oxide interface is determined. The oxygen partial pressure at the magnetite/supercritical water interface meets the equivalent oxygen partial pressure when system equilibrium has been attained. The relative error between calculated values and experimental values is analyzed and the reasons of error are suggested. The research results show that the results of simulation at 600°C are approximately close to experimental results. The iron diffusion coefficient is discontinuous in the duplex scale of two ferritic-martensitic steels. The simulation results of thicknesses of the oxide scale on tubes (T91 of final superheater of a 600 MW supercritical boiler are compared with field measurement data and calculation results by Adrian’s method. The calculated void positions of oxide scales are in good agreement with a cross-sectional SEM image of the oxide layers.

  8. Purifying waste waters in the surface treatment industry; Depuracion de las aguas residuales en la industria de tratamiento de superficies

    Energy Technology Data Exchange (ETDEWEB)

    Queralt Torrell, R.; Martinez Hidalgo, E. [Generalitat de Catalunya. Barcelona (Spain)

    1999-07-01

    The electrolytic coating industry in Spain comprises some 2,000 firms whose waste waters are highly problematic, mainly due to the presence of heavy metals and cyanides. This article sets out series of internal measures for conserving the baths, reducing entrainment and optimising washes, thereby minimising the volume and concentration of the waste waters. It also discusses the advantages and disadvantages of the different chemical reagents employed in the physicochemical treatment of waste waters during the oxidation/reduction and metal precipitation processes. In addition, it mentions other techniques such as the use of ion exchange resins, membranes and electro-coagulation, which are becoming increasingly widespread. Finally, it offers a summary report on 11 waste water treatment facilities installed in different surface treatment factories. (Author) 21 refs.

  9. Final Report: Fiscal Year 1997 demonstration of omnivorous non-thermal mixed waste treatment: Direct chemical oxidation of organic solids and liquids using peroxydisulfate

    International Nuclear Information System (INIS)

    Cooper, J.F.; Ballazs G.B.

    1998-01-01

    Direct Chemical Oxidation (DCO) is a non-thermal, ambient pressure, aqueous-based technology for the oxidative destruction of the organic components of hazardous or mixed waste streams. The process has been developed for applications in waste treatment, chemical demilitarization and decontamination at LLNL since 1992. The process uses solutions of the peroxydisulfate ion (typically sodium or ammonium salts) to completely mineralize the organics to carbon dioxide and water. The expended oxidant may be electrolytically regenerated to minimize secondary waste. The paper briefly describes: free radical and secondary oxidant formation; electrochemical regeneration; offgas stream; and throughput

  10. Final Report: Fiscal Year 1997 demonstration of omnivorous non-thermal mixed waste treatment: Direct chemical oxidation of organic solids and liquids using peroxydisulfate

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, J.F.

    1998-01-01

    Direct Chemical Oxidation (DCO) is a non-thermal, ambient pressure, aqueous-based technology for the oxidative destruction of the organic components of hazardous or mixed waste streams. The process has been developed for applications in waste treatment, chemical demilitarization and decontamination at LLNL since 1992. The process uses solutions of the peroxydisulfate ion (typically sodium or ammonium salts) to completely mineralize the organics to carbon dioxide and water. The expended oxidant may be electrolytically regenerated to minimize secondary waste. The paper briefly describes: free radical and secondary oxidant formation; electrochemical regeneration; offgas stream; and throughput.

  11. Ground water currents: Developments in innovative ground water treatment, March 1994

    Energy Technology Data Exchange (ETDEWEB)

    Eilers, R.

    1994-03-01

    ;Contents: Hydrodynamic cavitation oxidation destroys organics; Biosparging documented in fuel remediation study; Surfactant flushing research to remove organic liquids from aquifers; and Compilation of Ground-Water Models (a book review).

  12. Treatment of Some Hazardous Industrial Pollutants by Simple Oxidation Techniques

    International Nuclear Information System (INIS)

    Abd El-Rahman, N.M.

    1999-01-01

    Central treatment of Industrial wastewater requires pretreatment of some specific pollutants which may be not effectively degraded in down stream processes in central treatment unit. Some of the hazardous pollutants in industrial wastewater including acrylonitrile, pesticides and some commonly used dyes (active and acid dyes) have been subjected individually to oxidation using hydrogen peroxide catalyzed by ferrous ions in acidic solution. Treatment efficiency was monitored by chemical oxygen demand (COD) removal using a specially developed concentration/COD curves. Initial concentrations (in terms of COD) were 910 PPM, 1348 and 530 ppm and the respective COD reductions were 91, 98 and 99%, for the pesticide, acrylonitrile and the reactive dye. Oxidative degradation of polared and acid green also reduced COD by 99 and 100% respectively. The obtained results confirm the appropriateness of oxidative degradation as a pretreatment for some hazardous pollutants prior to treatment in central facilities or municipal activated sludge stations

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

    International Nuclear Information System (INIS)

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

    2012-01-01

    Highlights: ► We evaluate the use of an industrial residue (copper slag) as catalyst in water treatment. ► The copper slag was effective to remove organic pollutants (phenol) from water. ► During experimentation, Cu and Fe leaching were not higher than the acceptable levels. ► Slag/H 2 O 2 /UV and slag/H 2 O 2 treatments promoted biodegradability increment of the contaminated water. ► The control of the reaction time would minimize the environmental impact of the produced effluents in terms of acute toxicity. - Abstract: 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.

  14. Nitrous Oxide for Treatment-Resistant Major Depression: A Proof-of-Concept Trial.

    Science.gov (United States)

    Nagele, Peter; Duma, Andreas; Kopec, Michael; Gebara, Marie Anne; Parsoei, Alireza; Walker, Marie; Janski, Alvin; Panagopoulos, Vassilis N; Cristancho, Pilar; Miller, J Philip; Zorumski, Charles F; Conway, Charles R

    2015-07-01

    N-methyl-D-aspartate receptor antagonists, such as ketamine, have rapid antidepressant effects in patients with treatment-resistant depression (TRD). We hypothesized that nitrous oxide, an inhalational general anesthetic and N-methyl-D-aspartate receptor antagonist, may also be a rapidly acting treatment for TRD. In this blinded, placebo-controlled crossover trial, 20 patients with TRD were randomly assigned to 1-hour inhalation of 50% nitrous oxide/50% oxygen or 50% nitrogen/50% oxygen (placebo control). The primary endpoint was the change on the 21-item Hamilton Depression Rating Scale (HDRS-21) 24 hours after treatment. Mean duration of nitrous oxide treatment was 55.6 ± 2.5 (SD) min at a median inspiratory concentration of 44% (interquartile range, 37%-45%). In two patients, nitrous oxide treatment was briefly interrupted, and the treatment was discontinued in three patients. Depressive symptoms improved significantly at 2 hours and 24 hours after receiving nitrous oxide compared with placebo (mean HDRS-21 difference at 2 hours, -4.8 points, 95% confidence interval [CI], -1.8 to -7.8 points, p = .002; at 24 hours, -5.5 points, 95% CI, -2.5 to -8.5 points, p nitrous oxide and placebo, p nitrous oxide compared with one patient (5%) and none after placebo (odds ratio for response, 4.0, 95% CI, .45-35.79; OR for remission, 3.0, 95% CI, .31-28.8). No serious adverse events occurred; all adverse events were brief and of mild to moderate severity. This proof-of-concept trial demonstrated that nitrous oxide has rapid and marked antidepressant effects in patients with TRD. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  15. Optical modeling of nickel-base alloys oxidized in pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Clair, A. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex (France); Foucault, M.; Calonne, O. [Areva ANP, Centre Technique Departement Corrosion-Chimie, 30 Bd de l' industrie, BP 181, 71205 Le Creusot (France); Finot, E., E-mail: Eric.Finot@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078 Dijon cedex (France)

    2012-10-01

    The knowledge of the aging process involved in the primary water of pressurized water reactor entails investigating a mixed growth mechanism in the corrosion of nickel-base alloys. A mixed growth induces an anionic inner oxide and a cationic diffusion parallel to a dissolution-precipitation process forms the outer zone. The in situ monitoring of the oxidation kinetics requires the modeling of the oxide layer stratification with the full knowledge of the optical constants related to each component. Here, we report the dielectric constants of the alloys 600 and 690 measured by spectroscopic ellipsometry and fitted to a Drude-Lorentz model. A robust optical stratification model was determined using focused ion beam cross-section of thin foils examined by transmission electron microscopy. Dielectric constants of the inner oxide layer depleted in chromium were assimilated to those of the nickel thin film. The optical constants of both the spinels and extern layer were determined. - Highlights: Black-Right-Pointing-Pointer Spectroscopic ellipsometry of Ni-base alloy oxidation in pressurized water reactor Black-Right-Pointing-Pointer Measurements of the dielectric constants of the alloys Black-Right-Pointing-Pointer Optical simulation of the mixed oxidation process using a three stack model Black-Right-Pointing-Pointer Scattered crystallites cationic outer layer; linear Ni-gradient bottom layer Black-Right-Pointing-Pointer Determination of the refractive index of the spinel and the Cr{sub 2}O{sub 3} layers.

  16. Ozone-UV-catalysis based advanced oxidation process for wastewater treatment.

    Science.gov (United States)

    Tichonovas, Martynas; Krugly, Edvinas; Jankunaite, Dalia; Racys, Viktoras; Martuzevicius, Dainius

    2017-07-01

    A bench-scale advanced oxidation (AO) reactor was investigated for the degradation of six pollutants (2-naphthol, phenol, oxalic acid, phthalate, methylene blue, and D-glucose) in a model wastewater at with the aim to test opportunities for the further upscale to industrial applications. Six experimental conditions were designed to completely examine the experimental reactor, including photolysis, photocatalysis, ozonation, photolytic ozonation, catalytic ozonation, and photocatalytic ozonation. The stationary catalyst construction was made from commercially available TiO 2 nanopowder by mounting it on a glass support and subsequently characterized for morphology (X-ray diffraction analysis and scanning electron microscopy) as well as durability. The ozone was generated in a dielectrical barrier discharge reactor using air as a source of oxygen. The degradation efficiency was estimated by the decrease in total organic carbon (TOC) concentration as well as toxicity using Daphnia magna, and degradation by-products by ultra-performance liquid chromatography-mass spectrometry. The photocatalytic ozonation was the most effective for the treatment of all model wastewater. The photocatalytic ozonation was most effective against ozonation and photolytic ozonation at tested pH values. A complete toxicity loss was obtained after the treatment using photocatalytic ozonation. The possible degradation pathway of the phthalate by oxidation was suggested based on aromatic ring opening reactions. The catalyst used at this experiment confirmed as a durable for continuous use with almost no loss of activity over time. The design of the reactor was found to be very effective for water treatment using photocatalytic ozonation. Such design has a high potential and can be further upscaled to industrial applications due to the simplicity and versatility of manufacturing and maintenance.

  17. Emissions of nitrous oxide and methane from surface and ground waters in Germany

    International Nuclear Information System (INIS)

    Hiessl, H.

    1993-01-01

    The paper provides a first estimation of the contribution of inland freshwater systems (surface waters and ground waters) to the emission of the greenhouse gases nitrous oxide and methane in Germany. These amounts are compared to other main sources for the emission of nitrous oxide and methane. (orig.) [de

  18. Using Iron-Manganese Co-Oxide Filter Film to Remove Ammonium from Surface Water.

    Science.gov (United States)

    Zhang, Ruifeng; Huang, Tinglin; Wen, Gang; Chen, Yongpan; Cao, Xin; Zhang, Beibei

    2017-07-19

    An iron-manganese co-oxide filter film (MeO x ) has been proven to be a good catalyst for the chemical catalytic oxidation of ammonium in groundwater. Compared with groundwater, surface water is generally used more widely and has characteristics that make ammonium removal more difficult. In this study, MeO x was used to remove ammonium from surface water. It indicated that the average ammonium removal efficiency of MeO x was greater than 90%, even though the water quality changed dramatically and the water temperature was reduced to about 6-8 °C. Then, through inactivating microorganisms, it showed that the removal capability of MeO x included both biological (accounted for about 41.05%) and chemical catalytic oxidation and chemical catalytic oxidation (accounted for about 58.95%). The investigation of the characterizations suggested that MeO x was formed by abiotic ways and the main elements on the surface of MeO x were distributed homogenously. The analysis of the catalytic oxidation process indicated that ammonia nitrogen may interact with MeO x as both ammonia molecules and ammonium ions and the active species of O₂ were possibly • O and O₂ - .

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

  20. Electrosynthesis of Biomimetic Manganese-Calcium Oxides for Water Oxidation Catalysis--Atomic Structure and Functionality.

    Science.gov (United States)

    González-Flores, Diego; Zaharieva, Ivelina; Heidkamp, Jonathan; Chernev, Petko; Martínez-Moreno, Elías; Pasquini, Chiara; Mohammadi, Mohammad Reza; Klingan, Katharina; Gernet, Ulrich; Fischer, Anna; Dau, Holger

    2016-02-19

    Water-oxidizing calcium-manganese oxides, which mimic the inorganic core of the biological catalyst, were synthesized and structurally characterized by X-ray absorption spectroscopy at the manganese and calcium K edges. The amorphous, birnesite-type oxides are obtained through a simple protocol that involves electrodeposition followed by active-site creation through annealing at moderate temperatures. Calcium ions are inessential, but tune the electrocatalytic properties. For increasing calcium/manganese molar ratios, both Tafel slopes and exchange current densities decrease gradually, resulting in optimal catalytic performance at calcium/manganese molar ratios of close to 10 %. Tracking UV/Vis absorption changes during electrochemical operation suggests that inactive oxides reach their highest, all-Mn(IV) oxidation state at comparably low electrode potentials. The ability to undergo redox transitions and the presence of a minor fraction of Mn(III) ions at catalytic potentials is identified as a prerequisite for catalytic activity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Application of Metal Oxide Heterostructures in Arsenic Removal from Contaminated Water

    Directory of Open Access Journals (Sweden)

    Lei Chen

    2014-01-01

    Full Text Available It has become one of the major environmental problems for people worldwide to be exposed to high arsenic concentrations through contaminated drinking water, and even the long-term intake of small doses of arsenic has a carcinogenic effect. As an efficient and economic approach for the purification of arsenic-containing water, the adsorbents in adsorption processes have been widely studied. Among a variety of adsorbents reported, the metal oxide heterostructures with high surface area and specific affinity for arsenic adsorption from aqueous systems have demonstrated a promising performance in practical applications. This review paper aims to summarize briefly the metal oxide heterostructures in arsenic removal from contaminated water, so as to provide efficient, economic, and robust solutions for water purification.

  2. Supercritical water oxidation data acquisition testing. Final report, Volume I

    International Nuclear Information System (INIS)

    1996-11-01

    This report discusses the phase one testing of a data acquisition system for a supercritical water waste oxidation system. The system is designed to destroy a wide range of organic materials in mixed wastes. The design and testing of the MODAR Oxidizer is discussed. An analysis of the optimized runs is included

  3. Characterization of interfacial reactions and oxide films on 316L stainless steel in various simulated PWR primary water environments

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Junjie; Xiao, Qian [Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Mailbox 269, 149 Yanchang Road, Shanghai, 200072 (China); State Key Laboratory of Advanced Special Steels, Shanghai University, 149 Yanchang Road, Shanghai, 200072 (China); Lu, Zhanpeng, E-mail: zplu@t.shu.edu.cn [Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Mailbox 269, 149 Yanchang Road, Shanghai, 200072 (China); State Key Laboratory of Advanced Special Steels, Shanghai University, 149 Yanchang Road, Shanghai, 200072 (China); Shanghai Key Laboratory of Advanced Ferrometallurgy, Shanghai University, 149 Yanchang Road, Shanghai, 200072 (China); Ru, Xiangkun; Peng, Hao; Xiong, Qi; Li, Hongjuan [Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Mailbox 269, 149 Yanchang Road, Shanghai, 200072 (China)

    2017-06-15

    The effect of water chemistry on the electrochemical and oxidizing behaviors of 316L SS was investigated in hydrogenated, deaerated and oxygenated PWR primary water at 310 °C. Water chemistry significantly influenced the electrochemical impedance spectroscopy parameters. The highest charge-transfer resistance and oxide-film resistance occurred in oxygenated water. The highest electric double-layer capacitance and constant phase element of the oxide film were in hydrogenated water. The oxide films formed in deaerated and hydrogenated environments were similar in composition but different in morphology. An oxide film with spinel outer particles and a compact and Cr-rich inner layer was formed in both hydrogenated and deaerated water. Larger and more loosely distributed outer oxide particles were formed in deaerated water. In oxygenated water, an oxide film with hematite outer particles and a porous and Ni-rich inner layer was formed. The reaction kinetics parameters obtained by electrochemical impedance spectroscopy measurements and oxidation film properties relating to the steady or quasi-steady state conditions in the time-period of measurements could provide fundamental information for understanding stress corrosion cracking processes and controlling parameters. - Highlights: •Long-term EIS measurements of 316L SS in simulated PWR primary water. •Highest charge-transfer resistance and oxide film resistance in oxygenated water. •Highest electric double-layer capacitance and oxide film CPE in hydrogenated water. •Similar compositions, different shapes of oxides in deaerated/hydrogenated water. •Inner layer Cr-rich in hydrogenated/deaerated water, Ni-rich in oxygenated water.

  4. [Variation of water DOC during the process of pre-pressure and coagulation sedimentation treatment].

    Science.gov (United States)

    Chen, Wen-Jing; Cong, Hai-Bing; Xu, Ya-Jun; Wang, Wei; Jiang, Xin-Yue; Liu, Yu-Jiao

    2014-07-01

    The aim of the study was to explore whether the pre-pressure and coagulation sedimentation process would result in algal cell disruption, leading to increased dissolved organic carbon (DOC) in water, based on which, the pressure application mode would be optimized and safe and efficient pre-pressure algae removal process would be obtained. The changes in DOC during the process of pre-pressure and preoxidation treatment, the distribution of molecular weight in water as well as the removal efficiency of algae, turbidity and DOC after coagulation and sedimentation were investigated. The results showed that the DOC in water did not increase but decreased, and the molecular weight decreased after treated with 0.5-0.8 MPa pressure. While KMnO4 and NaClO pre-oxidation both increased the DOC, in the meanwhile, the distribution of molecular weight showed no obvious change. After the pre-pressure coagulation and sedimentation process, the removal rate of algae was 96.23% and that of DOC was 29. 11%, which was by 10% - 30% higher than the rate of pre-oxidation coagulation and sedimentation process.

  5. Nanotechnology-based water treatment strategies.

    Science.gov (United States)

    Kumar, Sandeep; Ahlawat, Wandit; Bhanjana, Gaurav; Heydarifard, Solmaz; Nazhad, Mousa M; Dilbaghi, Neeraj

    2014-02-01

    The most important component for living beings on the earth is access to clean and safe drinking water. Globally, water scarcity is pervasive even in water-rich areas as immense pressure has been created by the burgeoning human population, industrialization, civilization, environmental changes and agricultural activities. The problem of access to safe water is inevitable and requires tremendous research to devise new, cheaper technologies for purification of water, while taking into account energy requirements and environmental impact. This review highlights nanotechnology-based water treatment technologies being developed and used to improve desalination of sea and brackish water, safe reuse of wastewater, disinfection and decontamination of water, i.e., biosorption and nanoadsorption for contaminant removal, nanophotocatalysis for chemical degradation of contaminants, nanosensors for contaminant detection, different membrane technologies including reverse osmosis, nanofiltration, ultrafiltration, electro-dialysis etc. This review also deals with the fate and transport of engineered nanomaterials in water and wastewater treatment systems along with the risks associated with nanomaterials.

  6. Trace Element Removal in Distributed Drinking Water Treatment Systems by Cathodic H2O2 Production and UV Photolysis.

    Science.gov (United States)

    Barazesh, James M; Prasse, Carsten; Wenk, Jannis; Berg, Stephanie; Remucal, Christina K; Sedlak, David L

    2018-01-02

    As water scarcity intensifies, point-of-use and point-of-entry treatment may provide a means of exploiting locally available water resources that are currently considered to be unsafe for human consumption. Among the different classes of drinking water contaminants, toxic trace elements (e.g., arsenic and lead) pose substantial operational challenges for distributed drinking water treatment systems. Removal of toxic trace elements via adsorption onto iron oxides is an inexpensive and robust treatment method; however, the presence of metal-complexing ligands associated with natural organic matter (NOM) often prevents the formation of iron precipitates at the relatively low concentrations of dissolved iron typically present in natural water sources, thereby requiring the addition of iron which complicates the treatment process and results in a need to dispose of relatively large amounts of accumulated solids. A point-of-use treatment device consisting of a cathodic cell that produced hydrogen peroxide (H 2 O 2 ) followed by an ultraviolet (UV) irradiation chamber was used to decrease colloid stabilization and metal-complexing capacity of NOM present in groundwater. Exposure to UV light altered NOM, converting ∼6 μM of iron oxides into settable forms that removed between 0.5 and 1 μM of arsenic (As), lead (Pb), and copper (Cu) from solution via adsorption. After treatment, changes in NOM consistent with the loss of iron-complexing carboxylate ligands were observed, including decreases in UV absorbance and shifts in the molecular composition of NOM to higher H/C and lower O/C ratios. Chronoamperometric experiments conducted in synthetic groundwater revealed that the presence of Ca 2+ and Mg 2+ inhibited intramolecular charge-transfer within photoexcited NOM, leading to substantially increased removal of iron and trace elements.

  7. Effect of Magnesium Oxide Nanoparticles on Water Glass Structure

    Directory of Open Access Journals (Sweden)

    Bobrowski A.

    2012-09-01

    Full Text Available An attempt has been made to determine the effect of an addition of colloidal suspensions of the nanoparticles of magnesium oxide on the structure of water glass, which is a binder for moulding and core sands. Nanoparticles of magnesium oxide MgO in propanol and ethanol were introduced in the same mass content (5wt.% and structural changes were determined by measurement of the FT-IR absorption spectra.

  8. Mechanism of water oxidation by trivalent ruthenium trisdipyridyl complex

    International Nuclear Information System (INIS)

    Moravskij, A.P.; Khannanov, N.K.; Khramov, A.V.; Shafirovich, V.Ya.

    1983-01-01

    Results of kinetic investigation of water oxidation reaction with photogenerated single-electron oxidizer-trisdipyridyl complex of Ru(3) are presented. CoCl 2 x6H 2 O within the concentration range of [Co 2+ ] 0 =5x10 -7 - 5x10 -5 M was used as a reaction catalyst. The method of stopped flow with spectrophotometric recording was used in order to control the reaction kinetics

  9. Oil refinery wastewater treatment using physicochemical, Fenton and Photo-Fenton oxidation processes.

    Science.gov (United States)

    Tony, Maha A; Purcell, Patrick J; Zhao, Yaqian

    2012-01-01

    The objective of this study was to investigate the application of advanced oxidation processes (AOPs) to the treatment of wastewaters contaminated with hydrocarbon oil. Three different oil-contaminated wastewaters were examined and compared: (i) a 'real' hydrocarbon wastewater collected from an oil refinery (Conoco-Phillips Whitegate refinery, County Cork, Ireland); (ii) a 'real' hydrocarbon wastewater collected from a car-wash facility located at a petroleum filling station; and (iii) a 'synthetic' hydrocarbon wastewater generated by emulsifying diesel oil and water. The AOPs investigated were Fe(2+)/H(2)O(2) (Fenton's reagent), Fe(2+)/H(2)O(2)/UV (Photo-Fenton's reagent) which may be used as an alternative to, or in conjunction with, conventional treatment techniques. Laboratory-scale batch and continuous-flow experiments were undertaken. The photo-Fenton parametric concentrations to maximize COD removal were optimized: pH = 3, H(2)O(2) = 400 mg/L, and Fe(2+) = 40 mg/L. In the case of the oil-refinery wastewater, photo-Fenton treatment achieved approximately 50% COD removal and, when preceded by physicochemical treatment, the percentage removal increased to approximately 75%.

  10. Influence of pH-control in phosphoric acid treatment of zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    Onoda, H., E-mail: onoda@kpu.ac.jp [Department of Informatics and Environmental Sciences, Kyoto Prefectural University (Japan); Chemel, M. [Ecole de Biologie Industrielle, CERGY Cedex (France)

    2017-04-15

    Zinc oxide is often used as a white pigment for cosmetics; however, it shows photocatalytic activity that causes decomposition of sebum on the skin when exposed to the ultraviolet radiation in sunlight. In this work, zinc oxide was reacted with phosphoric acid at various pH values to synthesize a novel white pigment for cosmetics. The chemical composition, powder properties, photocatalytic activities, colors, and smoothness of these pigments were studied. The obtained materials exhibited X-ray diffraction peaks relating to zinc oxide and phosphate after phosphoric acid treatment. The ratio of zinc phosphate to zinc oxide was estimated from inductively coupled plasma - atomic emission spectroscopy results. Samples treated at pH 4-7 yielded small particles with sub-micrometer sizes. The photocatalytic activity of zinc oxide became lower after phosphoric acid treatment. Samples treated at pH 4-7 showed the same reflectance as zinc oxide in both the ultraviolet and visible ranges. Adjustment of the pH was found to be important in the phosphoric acid treatment of zinc oxide. (author)

  11. Enhancement of photocurrents due to the oxidation of water and organic compounds at BiZn2VO6 particulate thin film electrodes by treatment with a TiCl4 solution

    International Nuclear Information System (INIS)

    Liu Haimei; Imanishi, Akihito; Yang Wensheng; Nakato, Yoshihiro

    2010-01-01

    Photocurrents due to water oxidation at BiZn 2 VO 6 (E g 2.4 eV) particulate thin film electrodes were largely enhanced by pre-treatment with an aqueous TiCl 4 solution. Photocurrents for BiZn 2 VO 6 electrodes with no TiCl 4 treatment were also enhanced by the addition of organic compounds such as methanol and trimethyl amine to the aqueous electrolyte. Interestingly, such enhanced photocurrents by organic compounds were further enhanced by the TiCl 4 pre-treatment. EDAX and SEM investigations showed the formation of a flock-like TiO 2 overlayer on BiZn 2 VO 6 particles after the TiCl 4 treatment. The photocurrent enhancement by the TiCl 4 pre-treatment is thus mainly attributed to the necking effect of the flock-like TiO 2 overlayer, which facilitates the transport of photogenerated electrons within the BiZn 2 VO 6 particulate thin film electrode.

  12. Transformation of a Cp*-iridium(III) precatalyst for water oxidation when exposed to oxidative stress.

    Science.gov (United States)

    Zuccaccia, Cristiano; Bellachioma, Gianfranco; Bortolini, Olga; Bucci, Alberto; Savini, Arianna; Macchioni, Alceo

    2014-03-17

    The reaction of [Cp*Ir(bzpy)NO3 ] (1; bzpy=2-benzoylpyridine, Cp*=pentamethylcyclopentadienyl anion), a competent water-oxidation catalyst, with several oxidants (H2 O2 , NaIO4 , cerium ammonium nitrate (CAN)) was studied to intercept and characterize possible intermediates of the oxidative transformation. NMR spectroscopy and ESI-MS techniques provided evidence for the formation of many species that all had the intact Ir-bzpy moiety and a gradually more oxidized Cp* ligand. Initially, an oxygen atom is trapped in between two carbon atoms of Cp* and iridium, which gives an oxygen-Ir coordinated epoxide, whereas the remaining three carbon atoms of Cp* are involved in a η(3) interaction with iridium (2 a). Formal addition of H2 O to 2 a or H2 O2 to 1 leads to 2 b, in which a double MeCOH functionalization of Cp* is present with one MeCOH engaged in an interaction with iridium. The structure of 2 b was unambiguously determined in the solid state and in solution by X-ray single-crystal diffractometry and advanced NMR spectroscopic techniques, respectively. Further oxidation led to the opening of Cp* and transformation of the diol into a diketone with one carbonyl coordinated at the metal (2 c). A η(3) interaction between the three non-oxygenated carbons of "ex-Cp*" and iridium is also present in both 2 b and 2 c. Isolated 2 b and mixtures of 2 a-c species were tested in water-oxidation catalysis by using CAN as sacrificial oxidant. They showed substantially the same activity than 1 (turnover frequency values ranged from 9 to 14 min(-1) ). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Purification of ammonia-containing trap waters from atomic power plant by ozone treatment

    International Nuclear Information System (INIS)

    Grachok, M.A.; Prokudina, S.A.; Shulyat'ev, M.I.

    1990-01-01

    The aim of research was to study the process of ozonation of ammonia-containing trap waters from the Kursk Atomic Power Plant both on the model solutions and on real ones. Different factors (pH of the medium, temperature, concentration of the initial substances) have been studied for their effect on ozonation of aqueous ammonia solutions, model solutions of trap waters from the Kursk Atomic Power Plant as well as ammonia-containing trap waters and liquid radioactive wastes delivered to special water treatment at the Kursk Atomic Power Plant. It is shown that in all the cases the highest rate of ammonia oxidation by ozone is observed in the alkaline medium (pH 1.4-11.0) and at 55 deg C. The obtained results have shown that a method of ozonation followed by evaporation of water to be purified can be used to treat ammonia-containing waters from atomic power plant

  14. Chlorination of bromide-containing waters: enhanced bromate formation in the presence of synthetic metal oxides and deposits formed in drinking water distribution systems.

    Science.gov (United States)

    Liu, Chao; von Gunten, Urs; Croué, Jean-Philippe

    2013-09-15

    Bromate formation from the reaction between chlorine and bromide in homogeneous solution is a slow process. The present study investigated metal oxides enhanced bromate formation during chlorination of bromide-containing waters. Selected metal oxides enhanced the decay of hypobromous acid (HOBr), a requisite intermediate during the oxidation of bromide to bromate, via (i) disproportionation to bromate in the presence of nickel oxide (NiO) and cupric oxide (CuO), (ii) oxidation of a metal to a higher valence state in the presence of cuprous oxide (Cu2O) and (iii) oxygen formation by NiO and CuO. Goethite (α-FeOOH) did not enhance either of these pathways. Non-charged species of metal oxides seem to be responsible for the catalytic disproportionation which shows its highest rate in the pH range near the pKa of HOBr. Due to the ability to catalyze HOBr disproportionation, bromate was formed during chlorination of bromide-containing waters in the presence of CuO and NiO, whereas no bromate was detected in the presence of Cu2O and α-FeOOH for analogous conditions. The inhibition ability of coexisting anions on bromate formation at pH 8.6 follows the sequence of phosphate > sulfate > bicarbonate/carbonate. A black deposit in a water pipe harvested from a drinking water distribution system exerted significant residual oxidant decay and bromate formation during chlorination of bromide-containing waters. Energy dispersive spectroscopy (EDS) analyses showed that the black deposit contained copper (14%, atomic percentage) and nickel (1.8%, atomic percentage). Cupric oxide was further confirmed by X-ray diffraction (XRD). These results indicate that bromate formation may be of concern during chlorination of bromide-containing waters in distribution systems containing CuO and/or NiO. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Application of cylinder symmetry to iron and titanium oxidation by oxygen or hydrogen-water vapour mixes

    International Nuclear Information System (INIS)

    Raynaud, Pierre

    1980-01-01

    This research thesis addresses the study of the oxidation reaction in the case of corrosion of iron by oxygen, hydrogen sulphide or hydrogen-water vapour mixes, and in the case of oxidation of titanium and of titanium nitride by hydrogen-water vapour mixes. It first addresses the corrosion of iron by oxygen with an experiment performed in cylinder symmetry: description of operational conditions, discussion of kinetic curves, development of a law of generation of multiple layers in cylinder symmetry, analytical exploitation of experimental results. The second part addresses the oxidation of iron by hydrogen-water vapour mixes: experimental conditions, influence of temperature on kinetics, micrographic study (oxide morphology, coating morphology, interpretation of differences with the case of plane symmetry), discussion of the influence of cylinder symmetry on oxidation kinetics. The third part addresses the oxidation of titanium by hydrogen-water vapour mixes: global kinetic evolution, reaction products and micrographic examination, morphology and texture studies, discussion of the oxidation mechanism and of cylinder symmetry [fr

  16. Polyoxometalate electrocatalysts based on earth-abundant metals for efficient water oxidation in acidic media

    Science.gov (United States)

    Blasco-Ahicart, Marta; Soriano-López, Joaquín; Carbó, Jorge J.; Poblet, Josep M.; Galan-Mascaros, J. R.

    2018-01-01

    Water splitting is a promising approach to the efficient and cost-effective production of renewable fuels, but water oxidation remains a bottleneck in its technological development because it largely relies on noble-metal catalysts. Although inexpensive transition-metal oxides are competitive water oxidation catalysts in alkaline media, they cannot compete with noble metals in acidic media, in which hydrogen production is easier and faster. Here, we report a water oxidation catalyst based on earth-abundant metals that performs well in acidic conditions. Specifically, we report the enhanced catalytic activity of insoluble salts of polyoxometalates with caesium or barium counter-cations for oxygen evolution. In particular, the barium salt of a cobalt-phosphotungstate polyanion outperforms the state-of-the-art IrO2 catalyst even at pH < 1, with an overpotential of 189 mV at 1 mA cm-2. In addition, we find that a carbon-paste conducting support with a hydrocarbon binder can improve the stability of metal-oxide catalysts in acidic media by providing a hydrophobic environment.

  17. Using of ozone and UV in the treatment of N'djamena's municipal underground water

    International Nuclear Information System (INIS)

    Mohagir, A. M.; New, M. Tchadanaye; Nanadoum, M.; Tchadanaye, M.; Kapseu, C.; Kamga, R.; Tchiegang, C.; Bup, N. D.

    2008-01-01

    The presence of some epidemics such as cholera typhoid and renal failure were reported frequently in the last 3 years. Since the quality of potable water might be responsible for those diseases. this research work was focused on underground water of N'djamena's municipal on which almost all population of this capital used it as drinking water without purifications samples from 3 different locations were analysed for pH, Ca ++ , Fe ++ , Na + , C1 - , NO 3 - , and SO 4 2- . In addition some microbial analyses before and after treatment were done. Ozone and UV as oxidative and destructive agents were used among the procedure of treatment. The result revealed that filtration process has a significant at P> 0.01 for the removal of total hardness. On the other hand, using of ozone and UV showed a significant difference at P> 0.001 for overcoming the presence of bacteria and aerobic germs. Intensive research works were recommended to minimize the risk that could be associated with drinking water. (author)

  18. Bioremediation of mine water.

    Science.gov (United States)

    Klein, Robert; Tischler, Judith S; Mühling, Martin; Schlömann, Michael

    2014-01-01

    Caused by the oxidative dissolution of sulfide minerals, mine waters are often acidic and contaminated with high concentrations of sulfates, metals, and metalloids. Because the so-called acid mine drainage (AMD) affects the environment or poses severe problems for later use, treatment of these waters is required. Therefore, various remediation strategies have been developed to remove soluble metals and sulfates through immobilization using physical, chemical, and biological approaches. Conventionally, iron and sulfate-the main pollutants in mine waters-are removed by addition of neutralization reagents and subsequent chemical iron oxidation and sulfate mineral precipitation. Biological treatment strategies take advantage of the ability of microorganisms that occur in mine waters to metabolize iron and sulfate. As a rule, these can be grouped into oxidative and reductive processes, reflecting the redox state of mobilized iron (reduced form) and sulfur (oxidized form) in AMD. Changing the redox states of iron and sulfur results in iron and sulfur compounds with low solubility, thus leading to their precipitation and removal. Various techniques have been developed to enhance the efficacy of these microbial processes, as outlined in this review.

  19. Reversible switching of wetting properties and erasable patterning of polymer surfaces using plasma oxidation and thermal treatment

    Science.gov (United States)

    Rashid, Zeeshan; Atay, Ipek; Soydan, Seren; Yagci, M. Baris; Jonáš, Alexandr; Yilgor, Emel; Kiraz, Alper; Yilgor, Iskender

    2018-05-01

    Polymer surfaces reversibly switchable from superhydrophobic to superhydrophilic by exposure to oxygen plasma and subsequent thermal treatment are demonstrated. Two inherently different polymers, hydrophobic segmented polydimethylsiloxane-urea copolymer (TPSC) and hydrophilic poly(methyl methacrylate) (PMMA) are modified with fumed silica nanoparticles to prepare superhydrophobic surfaces with roughness on nanometer to micrometer scale. Smooth TPSC and PMMA surfaces are also used as control samples. Regardless of their chemical structure and surface topography, all surfaces display completely reversible wetting behavior changing from hydrophobic to hydrophilic and back for many cycles upon plasma oxidation followed by thermal annealing. Influence of plasma power, plasma exposure time, annealing temperature and annealing time on the wetting behavior of polymeric surfaces are investigated. Surface compositions, textures and topographies are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and white light interferometry (WLI), before and after oxidation and thermal annealing. Wetting properties of the surfaces are determined by measuring their static, advancing and receding water contact angle. We conclude that the chemical structure and surface topography of the polymers play a relatively minor role in reversible wetting behavior, where the essential factors are surface oxidation and migration of polymer molecules to the surface upon thermal annealing. Reconfigurable water channels on polymer surfaces are produced by plasma treatment using a mask and thermal annealing cycles. Such patterned reconfigurable hydrophilic regions can find use in surface microfluidics and optofluidics applications.

  20. Nonstoichiometric Titanium Oxides via Pulsed Laser Ablation in Water

    Directory of Open Access Journals (Sweden)

    Chen Shuei-Yuan

    2010-01-01

    Full Text Available Abstract Titanium oxide compounds TiO,Ti2O3, and TiO2 with a considerable extent of nonstoichiometry were fabricated by pulsed laser ablation in water and characterized by X-ray/electron diffraction, X-ray photoelectron spectroscopy and electron energy loss spectroscopy. The titanium oxides were found to occur as nanoparticle aggregates with a predominant 3+ charge and amorphous microtubes when fabricated under an average power density of ca. 1 × 108W/cm2 and 1011W/cm2, respectively followed by dwelling in water. The crystalline colloidal particles have a relatively high content of Ti2+ and hence a lower minimum band gap of 3.4 eV in comparison with 5.2 eV for the amorphous state. The protonation on both crystalline and amorphous phase caused defects, mainly titanium rather than oxygen vacancies and charge and/or volume-compensating defects. The hydrophilic nature and presumably varied extent of undercoordination at the free surface of the amorphous lamellae accounts for their rolling as tubes at water/air and water/glass interfaces. The nonstoichiometric titania thus fabricated have potential optoelectronic and catalytic applications in UV–visible range and shed light on the Ti charge and phase behavior of titania-water binary in natural shock occurrence.

  1. Photolytic AND Catalytic Destruction of Organic Waste Water Pollutants

    Science.gov (United States)

    Torosyan, V. F.; Torosyan, E. S.; Kryuchkova, S. O.; Gromov, V. E.

    2017-01-01

    The system: water supply source - potable and industrial water - wastewater - sewage treatment - water supply source is necessary for water supply and efficient utilization of water resources. Up-to-date technologies of waste water biological treatment require for special microorganisms, which are technologically complex and expensive but unable to solve all the problems. Application of photolytic and catalytically-oxidizing destruction is quite promising. However, the most reagents are strong oxidizers in catalytic oxidation of organic substances and can initiate toxic substance generation. Methodic and scientific approaches to assess bread making industry influence on the environment have been developed in this paper in order to support forecasting and taking technological decisions concerning reduction of this influence. Destructive methods have been tested: ultra violet irradiation and catalytic oxidation for extraction of organic compounds from waste water by natural reagents.

  2. Compatibility of the ultraviolet light-ozone system for laundry waste water treatment in nuclear power plants

    International Nuclear Information System (INIS)

    Matsuo, Toshiaki; Nishi, Takashi; Matsuda, Masami; Izumida, Tatsuo

    1997-01-01

    As an alternative treatment system for laundry waste water in nuclear power plants, a system was chosen in which such organic compounds as surfactant would be oxidized by ultraviolet (UV) light and ozone. The system compatibility, UV light source, and dissolved ozone concentration were examined through experiments. First, ozone gas was absorbed in the waste water. After the dissolved ozone concentration equilibrated at the desired value, the waste water was irradiated by a mercury lamp. Then, the time dependence of the concentrations of the organic compounds, the dissolved ozone, and the hydrogen peroxide were measured to estimate the treatment rate of the system. The mercury lamp with a 10 5 -Pa vapor pressure achieved large UV radiation and a treatment rate increase, leading to a compatible system without secondary waste generation. The effect of the dissolved ozone concentration on the treatment rate was saturated when concentration was >3.3 x 10 -4 mol/10 -3 m 3 at the time UV radiation was started. Numerical results indicated the saturation was due to hydrogen peroxide generation, which prevents hydroxyl radical generation

  3. Remediation of incomplete nitrification and capacity increase of biofilters at different drinking water treatment plants through copper dosing.

    Science.gov (United States)

    Wagner, Florian B; Nielsen, Peter Borch; Boe-Hansen, Rasmus; Albrechtsen, Hans-Jørgen

    2018-04-01

    Drinking water treatment plants based on groundwater may suffer from incomplete ammonium removal, which deteriorates drinking water quality and constrains water utilities in the operation of their plants. Ammonium is normally removed through nitrification in biological granular media filters, and recent studies have demonstrated that dosing of copper can stimulate the removal of ammonium. Here, we investigated if copper dosing could generically improve ammonium removal of biofilters, at treatment plants with different characteristics. Copper was dosed at ≤1.5 μg Cu/L to biofilters at 10 groundwater treatment plants, all of which had displayed several years of incomplete nitrification. Plants exceeded the Danish national water quality standard of 0.05 mg NH 4 + /L by a factor of 2-12. Within only 2-3 weeks of dosing, ammonium removal rates increased significantly (up to 150%). Nitrification was fully established, with ammonium effluent concentrations of plants, regardless of the differences in raw water chemistry, ammonium loading rates, filter design and operation, or treatment plant configuration. However, for filters without primary filtration, it took longer time to reach complete ammonium removal than for filters receiving prefiltered water, likely due to sorption of copper to iron oxides, at plants without prefiltration. With complete ammonium removal, we subjected two plants to short-term loading rate upshifts, to examine the filters' ability to cope with loading rate variations. After 2 months of dosing and an average loading rate of 1.0 g NH 4 + -N/m 3 filter material/h, the loading rate was upshifted by 50%. Yet, a filter managed to completely remove all the influent ammonium, showing that with copper dosing the filter had extra capacity to remove ammonium even beyond its normal loading rates. Depth sampling revealed that the ammonium removal rate of the filter's upper 10 cm increased more than 7-fold from 0.67 to 4.90 g NH 4 + -N/m 3 /h, and

  4. Study on emission characteristics and reduction strategy of nitrous oxide during wastewater treatment by different processes.

    Science.gov (United States)

    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.

  5. Fatigue and Oxidative Stress in Children Undergoing Leukemia Treatment.

    Science.gov (United States)

    Rodgers, Cheryl; Sanborn, Chelse; Taylor, Olga; Gundy, Patricia; Pasvogel, Alice; Moore, Ida M Ki; Hockenberry, Marilyn J

    2016-10-01

    Fatigue is a frequent and distressing symptom in children undergoing leukemia treatment; however, little is known about factors influencing this symptom. Antioxidants such as glutathione can decrease symptom severity in adult oncology patients, but no study has evaluated antioxidants' effects on symptoms in pediatric oncology patients. This study describes fatigue patterns and associations of fatigue with antioxidants represented by reduced glutathione (GSH) and the reduced/oxidized glutathione (GSH/GSSG) ratio among children receiving leukemia treatment. A repeated measures design assessed fatigue and antioxidants among 38 children from two large U.S. cancer centers. Fatigue was assessed among school-age children and by parent proxy among young children. Antioxidants (GSH and GSH/GSSG ratio) were assessed from cerebrospinal fluid at four phases during leukemia treatment. Young children had a steady decline of fatigue from the end of induction treatment through the continuation phase of treatment, but no significant changes were noted among the school-age children. Mean antioxidant scores varied slightly over time; however, the GSH/GSSG ratios in these children were significantly lower than the normal ratio. Mean GSH/GSSG ratios significantly correlated to fatigue scores of the school-age children during early phases of treatment. Children with low mean GSH/GSSG ratios demonstrated oxidative stress. The low ratios noted early in therapy were significantly correlated with higher fatigue scores during induction and postinduction treatment phases. This finding suggests that increased oxidative stress during the more intensive phases of therapy may explain the experience of fatigue children report. © The Author(s) 2016.

  6. Radiation induced oxidation for water remediation

    International Nuclear Information System (INIS)

    Gehringer, P.

    1997-01-01

    The action of ionizing radiation on halogenated hydrocarbons, in the presence and absence of ozone, was studied in water and wastewater. The combined ozone/electron-beam irradiation process was found especially suited for remediation of low-level contaminated groundwater. This combined treatment was often more effective than irradiation alone for wastewater decontamination. It reduced the COD without a simultaneous increase of BOD. Introduction of gaseous ozone directly into the irradiation chamber improved the water-flow turbulence, allowing treatment in layers thicker than the penetration range of the electrons, with increased decontamination efficiency. (author)

  7. Separation of radionuclides from water by magnesium oxide adsorption

    International Nuclear Information System (INIS)

    Tseng, Chia-Lian; Lo, Jem-Mau; Yeh, Si-Jung

    1987-01-01

    Adsorption by magnesium oxide of more than forty radionuclides in respective ionic species in water was observed. Generally, the radionuclides in di-valent and/or multi-valent cations are favorably adsorbed by magnesium oxide; but not for the those in mono-valent cations. In addition, the adsorption by magnesium oxide was not effective to most of the radionuclides in negative ionic species. From the observations, the adsorption mechanism is more prominently by the ion exchange of the di- or multi-valent cation species with the hydrous magnesium oxide. Separation of the radionuclides related to the corrosion products possibly produced in a nuclear power plant from natural seawater was attempted by the magnesium oxide adsorption method. It should be emphasized that the adsorption method was found to be practical for separating radionuclides from a large quantity of natural seawater with high recovery and high reproducibility. (author)

  8. Evaluation of industrial hydrotalcite for the sulfated water treatment of the Valle de Puebla

    International Nuclear Information System (INIS)

    Rosano O, G.

    2003-01-01

    In Puebla City, the drinking water is a scarce natural resource since at the moment it exists a deficit in its supply of more than 700 L/s. Nevertheless, the region has a system of aquifer: a first-aquifer known as superior, which is overexploited, and a half-aquifer characterized by water with gases (H 2 S, CO 2 ), high hardness (1270 mgL -1 as CaCO 3 ) alkalinity (1050 mgL -1 as CaCO 3 ) and high contents of different chemical species of sulfur (985 mgL -1 SO 4 2- , 6.2 mgL -1 S 2- , 43 mgL -1 SO 3 2- ). Up to now the treatment used in the city of Puebla for this type of water consists on the following stages: de gasification, oxidation, treatment of gases, system of softening, clotting/flocculation chemical-physical treatment, load high sedimentation, treatment and dehydration of sludge, quick filtration, inverse osmosis, blended of treated water and disinfection; which represents a complex treatment. The objective of this research, was to find an alternative treatment for this ground water, in order to obtain a drinking water and, consequently, to simplify operations. An industrial hydrotalcite (anionic clay available in large quantities) has been characterized, modified by means of thermal treatment and used. Sorption tests have been made with this hydrotalcite in batch sets and in columns, these experiments have allowed to check how the concentration of the characteristic parameters of the ground water such as the high hardness and the high contents of chemical species of sulfur decrease simultaneously. This removal has allowed to obtain values of these parameters quite below the permissible maximum limits for drinking water according to the mexican norms, with the exception of the p H since values of 10 are obtained (value limit: 6.5 - 8.5). Furthermore, the results of the sorption tests in columns allowed to calculate that a column packed with 8.35 kg of the industrial hydrotalcite modified thermally and granulated to mesh 18-20, and a contact time of t c

  9. Enhanced degradation of chitosan by applying plasma treatment in combination with oxidizing agents for potential use as an anticancer agent.

    Science.gov (United States)

    Chokradjaroen, Chayanaphat; Rujiravanit, Ratana; Watthanaphanit, Anyarat; Theeramunkong, Sewan; Saito, Nagahiro; Yamashita, Kazuko; Arakawa, Ryuichi

    2017-07-01

    Solution plasma (SP) treatment in combination with oxidizing agents, i.e., hydrogen peroxide (H 2 O 2 ), potassium persulfate (K 2 S 2 O 8 ) and sodium nitrite (NaNO 2 ) were adopted to chitosan degradation in order to achieve fast degradation rate, low chemicals used and high yield of low-molecular-weight chitosan and chitooligosaccharide (COS). Among the studied oxidizing agents, H 2 O 2 was found to be the best choice in terms of appreciable molecular weight reduction without major change in chemical structure of the degraded products of chitosan. By the combination with SP treatment, dilute solution of H 2 O 2 (4-60mM) was required for effective degradation of chitosan. The combination of SP treatment and dilute solution of H 2 O 2 (60mM) resulted in the great reduction of molecular weight of chitosan and water-soluble chitosan was obtained as a major product. The resulting water-soluble chitosan was precipitated to obtain COS. An inhibitory effect against cervical cancer cell line (HeLa cells) of COS was also examined. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Water Treatment Technology - Filtration.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on filtration provides instructional materials for six competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: purposes of sedimentation basins and flocculation…

  11. A new approach for water treatment

    CERN Document Server

    Principe, R

    1999-01-01

    A quantity of up to 4000 m3/h of water is used at CERN for cooling purposes: experiments, magnets and radio frequency cavities are refrigerated by closed circuits filled with deionized water; other utilities, such as air-conditioning, use chilled/hot water, also in closed circuits. All these methods all employ a cold source, the primary supply of water, coming from the cooling towers. About 500 kCHF are spent every year on water treatment in order to keep the water within these networks in operational conditions. In the line of further rationalization of resources, the next generation of contracts with the water treatment industry will aim for improved performance and better monitoring of quality related parameters in this context. The author will provide a concise report based upon an examination of the state of the installations and of the philosophy followed up until now for water treatment. Furthermore, he/she will propose a new approach from both a technical and contractual point of view, in preparation ...

  12. Pilot-scale equipment development for pyrochemical treatment of spent oxide fuel

    International Nuclear Information System (INIS)

    Herrmann, S. D.

    1999-01-01

    Fundamental objectives regarding spent nuclear fuel treatment technologies include, first, the effective distribution of spent fuel constituents among product and stable waste forms and, second, the minimization and standardization of waste form types and volumes. Argonne National Laboratory (ANL) has developed and is presently demonstrating the electrometallurgical treatment of sodium-bonded metal fuel from Experimental Breeder Reactor II, resulting in an uranium product and two stable waste forms, i.e. ceramic and metallic. Engineering efforts are underway at ANL to develop pilot-scale equipment which would precondition irradiated oxide fuel via pyrochemical processing and subsequently allow for electrometallurgical treatment of such non-metallic fuels into standard product and waste forms. This paper highlights the integration of proposed spent oxide fuel treatment with existing electrometallurgical processes. System designs and technical bases for development of pilot-scale oxide reduction equipment are also described

  13. Treatment of oilfield wastewater by combined process of micro-electrolysis, Fenton oxidation and coagulation.

    Science.gov (United States)

    Zhang, Zhenchao

    2017-12-01

    In this study, a combined process was developed that included micro-electrolysis, Fenton oxidation and coagulation to treat oilfield fracturing wastewater. Micro-electrolysis and Fenton oxidation were applied to reduce chemical oxygen demand (COD) organic load and to enhance organic components gradability, respectively. Orthogonal experiment were employed to investigate the influence factors of micro-electrolysis and Fenton oxidation on COD removal efficiency. For micro-electrolysis, the optimum conditions were: pH, 3; iron-carbon dosage, 50 mg/L; mass ratio of iron-carbon, 2:3; reaction time, 60 min. For Fenton oxidation, a total reaction time of 90 min, a H 2 O 2 dosage of 12 mg/L, with a H 2 O 2 /Fe 2+ mole ratio of 30, pH of 3 were selected to achieve optimum oxidation. The optimum conditions in coagulation process: pH, cationic polyacrylamide dosage, mixing speed and time is 4.3, 2 mg/L, 150 rpm and 30 s, respectively. In the continuous treatment process under optimized conditions, the COD of oily wastewater fell 56.95%, 46.23%, 30.67%, respectively, from last stage and the total COD removal efficiency reached 83.94% (from 4,314 to 693 mg/L). In the overall treatment process under optimized conditions, the COD of oily wastewater was reduced from 4,314 to 637 mg/L, and the COD removal efficiency reached 85.23%. The contribution of each stage is 68.45% (micro-electrolysis), 24.07% (Fenton oxidation), 7.48% (coagulation), respectively. Micro-electrolysis is the uppermost influencing process on COD removal. Compared with the COD removal efficiency of three processes on raw wastewater under optimized conditions: the COD removal efficiency of single micro-electrolysis, single Fenton oxidation, single coagulation is 58.34%, 44.88% and 39.72%, respectively. Experiments proved the effect of combined process is marvelous and the overall water quality of the final effluent could meet the class III national wastewater discharge standard of petrochemical industry of China

  14. In situ Raman Spectroscopy of Oxide Films on Zirconium Alloy in Simulated PWR Primary Water Condition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Ho; Choi, Kyoung Joon; Yoo, Seung Chang; Kim, Ji Hyun [UNIST, Ulsan (Korea, Republic of)

    2016-05-15

    The two layered oxide structure is formed in pre-transition oxide for the zirconium alloy in high temperature water environment. It is known that the corrosion rate is related to the volume fraction of zirconium oxide and the pores in the oxides; therefore, the aim of this paper is to investigate the oxidation behavior in the pretransition zirconium oxide in high-temperature water chemistry. In this work, Raman spectroscopy was used for in situ investigations for characterizing the phase of zirconium oxide. In situ Raman spectroscopy is a well-suited technique for investigating in detail the characteristics of oxide films in a high-temperature corrosion environment. In previous studies, an in situ Raman system was developed for investigating the oxides on nickel-based alloys and low alloy steels in high-temperature water environment. Also, the early stage oxidation behavior of zirconium alloy with different dissolved hydrogen concentration environments in high temperature water was treated in the authors' previous study. In this study, a specific zirconium alloy was oxidized and investigated with in situ Raman spectroscopy for 100 d oxidation, which is close to the first transition time of the zirconium alloy oxidation. The ex situ investigation methods such as transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) were used to further characterize the zirconium oxide structure. As oxidation time increased, the Raman peaks of tetragonal zirconium oxide were merged or became weaker. However, the monoclinic zirconium oxide peaks became distinct. The tetragonal zirconium oxide was just found near the O/M interface and this could explain the Raman spectra difference between the 30 d result and others.

  15. Destruction of an industrial wastewater by supercritical water oxidation in a transpiring wall reactor

    International Nuclear Information System (INIS)

    Bermejo, M.D.; Cocero, M.J.

    2006-01-01

    The supercritical water oxidation (SCWO) is a technology that takes advantage of the special properties of water in the surroundings of critical point of water to completely oxidize wastes in residence times lower than 1 min. The problems caused by the harsh operational conditions of the SCWO process are being solved by new reactor designs, such as the transpiring wall reactor (TWR). In this work, the operational parameters of a TWR have been studied for the treatment of an industrial wastewater. As a result, the process has been optimized for a feed flow of 16 kg/h with feed inlet temperatures higher than 300 deg. C and transpiring flow relation (R) between 0.2 and 0.6 working with an 8% (w/w) isopropanol (IPA) as a fuel. The experimental data and a mathematical model have been applied for the destruction of an industrial waste containing acetic acid and crotonaldehyde as main compounds. As the model predicted, removal efficiencies higher than 99.9% were obtained, resulting in effluents with 2 ppm total organic carbon (TOC) at feed flow of 16 kg/h, 320 deg. C of feed temperature and R = 0.32. An effluent TOC of 35 ppm under conditions feed flow of 18 kg/h, feed inlet temperatures of 290 deg. C, reaction temperatures of 570 deg. C and R = 0.6

  16. Iron Is the Active Site in Nickel/Iron Water Oxidation Electrocatalysts

    Directory of Open Access Journals (Sweden)

    Bryan M. Hunter

    2018-04-01

    Full Text Available Efficient catalysis of the oxygen-evolution half-reaction (OER is a pivotal requirement for the development of practical solar-driven water splitting devices. Heterogeneous OER electrocatalysts containing first-row transition metal oxides and hydroxides have attracted considerable recent interest, owing in part to the high abundance and low cost of starting materials. Among the best performing OER electrocatalysts are mixed Fe/Ni layered double hydroxides (LDH. A review of the available experimental data leads to the conclusion that iron is the active site for [NiFe]-LDH-catalyzed alkaline water oxidation.

  17. Electrolysis of water on (oxidized) metal surfaces

    DEFF Research Database (Denmark)

    Rossmeisl, Jan; Logadottir, Ashildur; Nørskov, Jens Kehlet

    2005-01-01

    Density functional theory calculations are used as the basis for an analysis of the electrochemical process, where by water is split to form molecular oxygen and hydrogen. We develop a method for obtaining the thermochemistry of the electrochemical water splitting process as a function of the bias...... directly from the electronic structure calculations. We consider electrodes of Pt(111) and Au(111) in detail and then discuss trends for a series of different metals. We show that the difficult step in the water splitting process is the formation of superoxy-type (OOH) species on the surface...... by the splitting of a water molecule on top an adsorbed oxygen atom. One conclusion is that this is only possible on metal surfaces that are (partly) oxidized. We show that the binding energies of the different intermediates are linearly correlated for a number of metals. In a simple analysis, where the linear...

  18. The advanced EctoSys electrolysis as an integral part of a ballast water treatment system.

    Science.gov (United States)

    Echardt, J; Kornmueller, A

    2009-01-01

    A full-scale 500 m(3)/h ballast water treatment system was tested according to the landbased type approval procedure of the International Maritime Organization (IMO). The system consists of disc filters followed by the advanced EctoSys electrolysis as an integral part for disinfection. The test water quality exceeded by far the minimum requirements for type approval testing. Due to the properties of the special electrodes used together with the striking disinfection effect, the disinfectants assumed to be produced inline by the EctoSys cell in river water were hydroxyl radicals, while in brackish water additionally chlorine and consequently the more stable bromine were formed. In river water, no residual oxidants could be detected in accordance with the assumed production of not responding, highly-reactive and short-living hydroxyl radicals. Accordingly, disinfection byproduct (DBP) formation was very low and close to the limit of quantification in river water. While in brackish water, initial residual oxidant concentrations were maximum 2 mg/L as chlorine and mostly brominated DBP (especially bromoform and bromate) were found. Overall considering this worst case test approach, the DBP concentrations of the treated effluents were below or in the range of the WHO Drinking Water Guideline values and therefore evaluated as acceptable for discharge to the environment. The stringent discharge standard by IMO concerning viable organisms was fully met in river and brackish water, proving the disinfection efficiency of the EctoSys electrolysis against smaller plankton and bacteria.

  19. Photoanodic Hybrid Semiconductor–Molecular Heterojunction for Solar Water Oxidation

    KAUST Repository

    Joya, Khurram Saleem; Takanabe, Kazuhiro

    2015-01-01

    Inorganic photo-responsive semiconducting materials have been employed in photoelectrochemical(PEC) water oxidation devicesin pursuit of solar to fuel conversion.[1]The reaction kinetics in semiconductors is limited by poor contact at the interfaces

  20. Water surface coverage effects on reactivity of plasma oxidized Ti films

    International Nuclear Information System (INIS)

    Pranevicius, L.; Pranevicius, L.L.; Vilkinis, P.; Baltaragis, S.; Gedvilas, K.

    2014-01-01

    Highlights: • The reactivity of Ti films immersed in water vapor plasma depends on the surface water coverage. • The adsorbed water monolayers are disintegrated into atomic constituents on the hydrophilic TiO 2 under plasma radiation. • The TiO 2 surface covered by water multilayer loses its ability to split adsorbed water molecules under plasma radiation. - Abstract: The behavior of the adsorbed water on the surface of thin sputter deposited Ti films maintained at room temperature was investigated in dependence on the thickness of the resulting adsorbed water layer, controllably injecting water vapor into plasma. The surface morphology and microstructure were used to characterize the surfaces of plasma treated titanium films. Presented experimental results showed that titanium films immersed in water vapor plasma at pressure of 10–100 Pa promoted the photocatalytic activity of overall water splitting. The surfaces of plasma oxidized titanium covered by an adsorbed hydroxyl-rich island structure water layer and activated by plasma radiation became highly chemically reactive. As water vapor pressure increased up to 300–500 Pa, the formed water multilayer diminished the water oxidation and, consequently, water splitting efficiency decreased. Analysis of the experimental results gave important insights into the role an adsorbed water layer on surface of titanium exposed to water vapor plasma on its chemical activity and plasma activated electrochemical processes, and elucidated the surface reactions that could lead to the split of water molecules

  1. Incorporation of Graphene-Related Carbon Nanosheets in Membrane Fabrication for Water Treatment: A Review

    Directory of Open Access Journals (Sweden)

    Jenny Lawler

    2016-12-01

    Full Text Available The minimization of the trade-off between the flux and the selectivity of membranes is a key area that researchers are continually working to optimise, particularly in the area of fabrication of novel membranes. Flux versus selectivity issues apply in many industrial applications of membranes, for example the unwanted diffusion of methanol in fuel cells, retention of valuable proteins in downstream processing of biopharmaceuticals, rejection of organic matter and micro-organisms in water treatment, or salt permeation in desalination. The incorporation of nanosheets within membrane structures can potentially lead to enhancements in such properties as the antifouling ability, hydrophilicy and permeability of membranes, with concomitant improvements in the flux/selectivity balance. Graphene nanosheets and derivatives such as graphene oxide and reduced graphene oxide have been investigated for this purpose, for example inclusion of nanosheets within the active layer of Reverse Osmosis or Nanofiltration membranes or the blending of nanosheets as fillers within Ultrafiltration membranes. This review summarizes the incorporation of graphene derivatives into polymeric membranes for water treatment with a focus on a number of industrial applications, including desalination and pharmaceutical removal, where enhancement of productivity and reduction in fouling characteristics have been afforded by appropriate incorporation of graphene derived nanosheets during membrane fabrication.

  2. UO{sub 2} surface oxidation by mixtures of water vapor and hydrogen as a function of temperature

    Energy Technology Data Exchange (ETDEWEB)

    Espriu-Gascon, A., E-mail: alexandra.espriu@upc.edu [Department of Chemical Engineering, Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Llorca, J.; Domínguez, M. [Institut de Tècniques Energètiques (INTE), Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE), Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Giménez, J.; Casas, I. [Department of Chemical Engineering, Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Pablo, J. de [Department of Chemical Engineering, Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Fundació CTM Centre Tecnològic, Plaça de la Ciència 2, E-08243 Manresa (Spain)

    2015-12-15

    In the present work, X-Ray Photoelectron Spectroscopy (XPS) was used to study the effect of water vapor on the UO{sub 2} surface as a function of temperature. The experiments were performed in situ inside a high pressure chamber attached to the XPS instrument. UO{sub 2} samples were put in contact with either hydrogen or argon streams, saturated with water at room temperature, and the sample surface evolution was analyzed by XPS. In the case of the water vapor/argon experiments, one experiment at 350 °C was performed and, in the case of the water vapor/hydrogen experiments, the temperatures used inside the reactor were 60, 120, 200 and 350 °C. On one hand, in presence of argon, the results obtained showed that the water vapor in the argon stream oxidized 93% of the U(IV) in the sample surface. On the other hand, the degree of UO{sub 2} surface oxidation showed a different dependence on the temperature in the experiments performed in the presence of hydrogen: the maximum surface oxidation occurred at 120 °C, where 65.4% of U(IV) in the sample surface was oxidized, while at higher temperatures, the surface oxidation decreased. This observation is attributed to the increase of hydrogen reducing effect when temperature increases which prevents part of the oxidation of the UO{sub 2} surface by the water vapor. - Highlights: • UO{sub 2} surface has been oxidized by water vapor in an argon stream at 350 °C. • H{sub 2} reduced more uranium oxidation produced by water at 350 °C when compared to Ar. • In H{sub 2} presence, the uranium oxidation produced by water depends on the temperature.

  3. Development of nanomaterial-enabled advanced oxidation techniques for treatment of organic micropollutants

    Science.gov (United States)

    Oulton, Rebekah Lynn

    Increasing demand for limited fresh water resources necessitates that alternative water sources be developed. Nonpotable reuse of treated wastewater represents one such alternative. However, the ubiquitous presence of organic micropollutants such as pharmaceuticals and personal care products (PPCPs) in wastewater effluents limits use of this resource. Numerous investigations have examined PPCP fate during wastewater treatment, focusing on their removal during conventional and advanced treatment processes. Analysis of influent and effluent data from published studies reveals that at best 1-log10 concentration unit of PPCP removal can generally be achieved with conventional treatment. In contrast, plants employing advanced treatment methods, particularly ozonation and/or membranes, remove most PPCPs often to levels below analytical detection limits. However, membrane treatment is cost prohibitive for many facilities, and ozone treatment can be very selective. Ozone-recalcitrant compounds require the use of Advanced Oxidation Processes (AOPs), which utilize highly reactive hydroxyl radicals (*OH) to target resistant pollutants. Due to cost and energy use concerns associated with current AOPs, alternatives such as catalytic ozonation are under investigation. Catalytic ozonation uses substrates such as activated carbon to promote *OH formation during ozonation. Here, we show that multi-walled carbon nanotubes (MWCNTs) represent another viable substrate, promoting *OH formation during ozonation to levels exceeding activated carbon and equivalent to conventional ozone-based AOPs. Via a series of batch reactions, we observ a strong correlation between *OH formation and MWCNT surface oxygen concentrations. Results suggest that deprotonated carboxyl groups on the CNT surface are integral to their reactivity toward ozone and corresponding *OH formation. From a practical standpoint, we show that industrial grade MWCNTs exhibit similar *OH production as their research

  4. The formation and growing properties of poly(ethylene terephthalate) fiber growing media after thermo-oxidative treatment

    International Nuclear Information System (INIS)

    Chang, C.P.; Lin, S.M.

    2007-01-01

    This research uses three kinds of recycled synthetic fibers that all possess excellent thermal plasticity property as raw material to develop a new firm cultivation media: polyethylene terephthalate, polyamide and polypropylene. One can not only freely control plants cultivation growing condition by changing bulk density of the media, but also solve disposal problem after usage by applying thermal oxidative treatment during manufacturing processes. The water content, air permeability and formation conditions of these fiber growing media that are required in plants growing habitat were discussed, and compared the fallout with rockwool (RW) growing media that is commonly used at present days. The results indicated that the polyethylene terephthalate fiber media could attain best formation characteristics among these fibers at the same bulk density range. Furthermore, the fiber media that were thermo-oxidative treated at 240-260 deg. C could obtained above 90% total porosity, 23-49% air capacity and 48-68% water availability, water contents raised from 1735-1094 to 2145-1156% under bulk densities of 0.03-0.09 g/cm 3 , which conforms to the common plant growing habitat conditions. Its performance well surpasses the rockwool growing media. We also discovered that the thermo-oxidative treated polyethylene terephthalate (PET) fiber media could be easily broken down and become powdery by exerting pressure, thus greatly reduce its volume and effectively improve disposal processes that are difficult presently for the huge refuse create by rockwool

  5. Improved Energy Recovery by Anaerobic Grey Water Sludge Treatment with Black Water

    OpenAIRE

    Tervahauta, Taina; Bryant, Isaac; Leal, Lucía; Buisman, Cees; Zeeman, Grietje

    2014-01-01

    This study presents the potential of combining anaerobic grey water sludge treatment with black water in an up-flow anaerobic sludge blanket (UASB) reactor to improve energy recovery within source-separated sanitation concepts. Black water and the mixture of black water and grey water sludge were compared in terms of biochemical methane potential (BMP), UASB reactor performance, chemical oxygen demand (COD) mass balance and methanization. Grey water sludge treatment with black water increased...

  6. Water Treatment Technology - Wells.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on wells provides instructional materials for five competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: dug, driven, and chilled wells, aquifer types, deep well…

  7. Water Treatment Technology - Hydraulics.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on hydraulics provides instructional materials for three competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: head loss in pipes in series, function loss in…

  8. Effects of ozone and ozone/peroxide on trace organic contaminants and NDMA in drinking water and water reuse applications.

    Science.gov (United States)

    Pisarenko, Aleksey N; Stanford, Benjamin D; Yan, Dongxu; Gerrity, Daniel; Snyder, Shane A

    2012-02-01

    An ozone and ozone/peroxide oxidation process was evaluated at pilot scale for trace organic contaminant (TOrC) mitigation and NDMA formation in both drinking water and water reuse applications. A reverse osmosis (RO) pilot was also evaluated as part of the water reuse treatment train. Ozone/peroxide showed lower electrical energy per order of removal (EEO) values for TOrCs in surface water treatment, but the addition of hydrogen peroxide increased EEO values during wastewater treatment. TOrC oxidation was correlated to changes in UV(254) absorbance and fluorescence offering a surrogate model for predicting contaminant removal. A decrease in N-nitrosodimethylamine (NDMA) formation potential (after chloramination) was observed after treatment with ozone and ozone/peroxide. However, during spiking experiments with surface water, ozone/peroxide achieved limited destruction of NDMA, while in wastewaters net direct formation of NDMA of 6-33 ng/L was observed after either ozone or ozone/peroxide treatment. Once formed during ozonation, NDMA passed through the subsequent RO membranes, which highlights the significance of the potential for direct NDMA formation during oxidation in reuse applications. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Salt and nitric oxide synthase inhibition-induced hypertension: kidney dysfunction and brain anti-oxidant capacity.

    Science.gov (United States)

    Oktar, Süleyman; Ilhan, Selçuk; Meydan, Sedat; Aydin, Mehmet; Yönden, Zafer; Gökçe, Ahmet

    2010-01-01

    The specific aim of this study was to examine the effects of salt-loading on kidney function and brain antioxidant capacity. Wistar rats were divided into four groups: Control rats were given normal drinking water and no drug treatment for 2 weeks. LNNA group: rats were given normal drinking water and the nitric oxide (NO) inhibitor NG-nitro-L-arginine (L-NNA), 3 mg/kg/day. LNNA + Salt group: rats were given drinking water containing salt 2% and 3 mg/kg L-NNA. Salt group: rats were given drinking water containing salt 2% and no drug treatment. Basal blood pressure and the levels of serum BUN, creatinine, uric acid, cortisol, electrolyte, serum antioxidant capacity, and oxidative stress were measured. NO, superoxide dismutase (SOD), and catalase (CAT) levels were measured in the hypothalamus, brainstem, and cerebellum. Salt overload increased the blood pressure of the LNNA + Salt group. Salt-loading enhanced BUN, creatinine, sodium retention. High salt produced an increase in uric acid levels and a decrease in cortisol levels in serum. Additionally, the oxidative stress index in serum increased in the LNNA + Salt group. Salt-loading enhanced brain NO levels, but not SOD and CAT activity. L-NNA increased brain SOD activity, but not CAT and NO levels. In conclusion, salt-loading causes hypertension, kidney dysfunction, and enhances oxidative stress in salt-sensitive rats.

  11. Use of gas-phase ethanol to mitigate extreme UV/water oxidation of extreme UV optics

    Science.gov (United States)

    Klebanoff, L. E.; Malinowski, M. E.; Clift, W. M.; Steinhaus, C.; Grunow, P.

    2004-03-01

    A technique is described that uses a gas-phase species to mitigate the oxidation of a Mo/Si multilayer optic caused by either extreme UV (EUV) or electron-induced dissociation of adsorbed water vapor. It is found that introduction of ethanol (EtOH) into a water-rich gas-phase environment inhibits oxidation of the outermost Si layer of the Mo/Si EUV reflective coating. Auger electron spectroscopy, sputter Auger depth profiling, EUV reflectivity, and photocurrent measurements are presented that reveal the EUV/water- and electron/water-derived optic oxidation can be suppressed at the water partial pressures used in the tests (~2×10-7-2×10-5 Torr). The ethanol appears to function differently in two time regimes. At early times, ethanol decomposes on the optic surface, providing reactive carbon atoms that scavenge reactive oxygen atoms before they can oxidize the outermost Si layer. At later times, the reactive carbon atoms form a thin (~5 Å), possibly self-limited, graphitic layer that inhibits water adsorption on the optic surface. .

  12. Testing of unlubricated water-immersed carbon-steel ball bearings

    International Nuclear Information System (INIS)

    Wensel, R.G.

    1977-07-01

    Wear data for untreated, chemically oxidized, autoclave oxidized, and hard chromium plated ball bearings operating in water at different radial loads, speeds and water temperatures are presented. Results were highly variable, even for replicated tests, making wear results difficult to interpret. Within the ranges used in these tests, load, speed and water temperature had no consistent effect on wear rate or operating torque. One treatment, the Du-Lite process, resulted in a significant reduction in wear rate. All oxide-forming treatments studied, resulted in improved corrosion resistance. (author)

  13. Targeting oxidant-dependent mechanisms for the treatment of COPD and its comorbidities.

    Science.gov (United States)

    Bernardo, Ivan; Bozinovski, Steven; Vlahos, Ross

    2015-11-01

    Chronic obstructive pulmonary disease (COPD) is an incurable global health burden and is characterised by progressive airflow limitation and loss of lung function. In addition to the pulmonary impact of the disease, COPD patients often develop comorbid diseases such as cardiovascular disease, skeletal muscle wasting, lung cancer and osteoporosis. One key feature of COPD, yet often underappreciated, is the contribution of oxidative stress in the onset and development of the disease. Patients experience an increased burden of oxidative stress due to the combined effects of excess reactive oxygen species (ROS) and nitrogen species (RNS) generation, antioxidant depletion and reduced antioxidant enzyme activity. Currently, there is a lack of effective treatments for COPD, and an even greater lack of research regarding interventions that treat both COPD and its comorbidities. Due to the involvement of oxidative stress in the pathogenesis of COPD and many of its comorbidities, a unique therapeutic opportunity arises where the treatment of a multitude of diseases may be possible with only one therapeutic target. In this review, oxidative stress and the roles of ROS/RNS in the context of COPD and comorbid cardiovascular disease, skeletal muscle wasting, lung cancer, and osteoporosis are discussed and the potential for therapeutic benefit of anti-oxidative treatment in these conditions is outlined. Because of the unique interplay between oxidative stress and these diseases, oxidative stress represents a novel target for the treatment of COPD and its comorbidities. Copyright © 2015. Published by Elsevier Inc.

  14. Computational Modeling of Cobalt-based Water Oxidation: Current Status and Future Challenges

    Science.gov (United States)

    Schilling, Mauro; Luber, Sandra

    2018-04-01

    A lot of effort is nowadays put into the development of novel water oxidation catalysts. In this context mechanistic studies are crucial in order to elucidate the reaction mechanisms governing this complex process, new design paradigms and strategies how to improve the stability and efficiency of those catalysis. This review is focused on recent theoretical mechanistic studies in the field of homogeneous cobalt-based water oxidation catalysts. In the first part, computational methodologies and protocols are summarized and evaluated on the basis of their applicability towards real catalytic or smaller model systems, whereby special emphasis is laid on the choice of an appropriate model system. In the second part, an overview of mechanistic studies is presented, from which conceptual guidelines are drawn on how to approach novel studies of catalysts and how to further develop the field of computational modeling of water oxidation reactions.

  15. Computational Modeling of Cobalt-Based Water Oxidation: Current Status and Future Challenges

    Directory of Open Access Journals (Sweden)

    Mauro Schilling

    2018-04-01

    Full Text Available A lot of effort is nowadays put into the development of novel water oxidation catalysts. In this context, mechanistic studies are crucial in order to elucidate the reaction mechanisms governing this complex process, new design paradigms and strategies how to improve the stability and efficiency of those catalysts. This review is focused on recent theoretical mechanistic studies in the field of homogeneous cobalt-based water oxidation catalysts. In the first part, computational methodologies and protocols are summarized and evaluated on the basis of their applicability toward real catalytic or smaller model systems, whereby special emphasis is laid on the choice of an appropriate model system. In the second part, an overview of mechanistic studies is presented, from which conceptual guidelines are drawn on how to approach novel studies of catalysts and how to further develop the field of computational modeling of water oxidation reactions.

  16. On the effect of interaction of molybdenum trioxide and magnesium oxide in water

    International Nuclear Information System (INIS)

    Bunin, V.M.; Karelin, A.I.; Solov'eva, L.N.

    1992-01-01

    Interaction of molybdenum trioxide and magnesium oxide in water was studied. It is shown that molybdenum trioxide forms consecutively magnesium molybdate, dimolybdate and magnesium polymolybdates with magnesium oxide

  17. Development of a lab-scale contaminated organic effluents treatment process using evaporation and supercritical water oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Turc, H.A.; Joussot-Dubien, C

    2004-07-01

    The organic liquid waste produced in the ATALANTE facility have to be treated in order to reduce the fire and contamination risks. Therefore, the Mini-DELOS process has been developed, which combines a low pressure evaporator in a shielded enclosure and a continuous supercritical water oxidation (SCWO) reactor in a glovebox. Evaporation makes it possible to evacuate the main organic stream as decontaminated distillates to an industrial incinerator. The remaining residue, concentrating the radioactivity can be converted through SCWO into a contaminated aqueous effluent, fully compatible with the existing outlets of the facility. The preliminary results of the first year of active operation of the Mini- DELOS process are here presented. (authors)

  18. Stable Water Oxidation in Acid Using Manganese-Modified TiO2 Protective Coatings.

    Science.gov (United States)

    Siddiqi, Georges; Luo, Zhenya; Xie, Yujun; Pan, Zhenhua; Zhu, Qianhong; Röhr, Jason A; Cha, Judy J; Hu, Shu

    2018-06-06

    Accomplishing acid-stable water oxidation is a critical matter for achieving both long-lasting water-splitting devices and other fuel-forming electro- and photocatalytic processes. Because water oxidation releases protons into the local electrolytic environment, it becomes increasingly acidic during device operation, which leads to corrosion of the photoactive component and hence loss in device performance and lifetime. In this work, we show that thin films of manganese-modified titania, (Ti,Mn)O x , topped with an iridium catalyst, can be used in a coating stabilization scheme for acid-stable water oxidation. We achieved a device lifetime of more than 100 h in pH = 0 acid. We successfully grew (Ti,Mn)O x coatings with uniform elemental distributions over a wide range of manganese compositions using atomic layer deposition (ALD), and using X-ray photoelectron spectroscopy, we show that (Ti,Mn)O x films grown in this manner give rise to closer-to-valence-band Fermi levels, which can be further tuned with annealing. In contrast to the normally n-type or intrinsic TiO 2 coatings, annealed (Ti,Mn)O x films can make direct charge transfer to a Fe(CN) 6 3-/4- redox couple dissolved in aqueous electrolytes. Using the Fe(CN) 6 3-/4- redox, we further demonstrated anodic charge transfer through the (Ti,Mn)O x films to high work function metals, such as iridium and gold, which is not previously possible with ALD-grown TiO 2 . We correlated changes in the crystallinity (amorphous to rutile TiO 2 ) and oxidation state (2+ to 3+) of the annealed (Ti,Mn)O x films to their hole conductivity and electrochemical stability in acid. Finally, by combining (Ti,Mn)O x coatings with iridium, an acid-stable water-oxidation anode, using acid-sensitive conductive fluorine-doped tin oxides, was achieved.

  19. Zirconium metal-water oxidation kinetics. I. Thermometry

    International Nuclear Information System (INIS)

    Cathcart, J.V.; McElroy, D.L.; Pawel, R.E.; Perkins, R.A.; Williams, R.K.; Yurek, G.J.

    1976-02-01

    A description is given of the thermometry techniques used in the Zirconium Metal--Water Oxidation Kinetics Program. Temperature measurements in the range 900 to 1500 0 C are made in three experimental systems: two oxidation apparatuses and the annealing furnace used in a corollary study of the diffusion of oxygen in β-Zircaloy. Carefully calibrated Pt vs Pt--10 percent Rh thermocouples are employed in all three apparatuses, while a Pt--6 percent Rh vs Pt-- 30 percent Rh thermocouple and an optical pyrometer are used in addition in the annealing furnace. Features of the experimental systems pertaining to thermocouple installation, temperature control, emf measurements, etc. are described, and potential temperature-measurement error sources are discussed in detail. The accuracy of the temperature measurements is analyzed

  20. Deteriorations of pulmonary function, elevated carbon monoxide levels and increased oxidative stress amongst water-pipe smokers

    Directory of Open Access Journals (Sweden)

    Funda Karaduman Yalcin

    2017-10-01

    Full Text Available Objectives: A water pipe (hookah is a tobacco smoking tool which is thought to be more harmless than a cigarette, and there are no adequate studies about its hazards to health. Water-pipe smoking is threatening health of the youth in the world today. The objective of this study has been to investigate the carbon monoxide (CO levels in breath, examine the changes in pulmonary function tests (PFT and to assess the change of the oxidative stress parameters in blood after smoking a water pipe. Material and Methods: This study is a cross-sectional analytical study that has included 50 volunteers who smoke a water pipe and the control group of 50 volunteers who smoke neither a cigarette nor a water pipe. Carbon monoxide levels were measured in the breath and pulmonary function tests (PFTs were performed before and after smoking a water pipe. Blood samples were taken from either the volunteer control group or water-pipe smokers group after smoking a water pipe for the purpose of evaluation of the parameters of oxidative stress. Results: Carbon monoxide values were measured to be 8.08±7.4 ppm and 28.08±16.5 ppm before and after smoking a water pipe, respectively. This increment was found statistically significant. There were also significant reductions in PFTs after smoking a water pipe. Total oxidative status (TOS, total antioxidant status (TAS and oxidative stress index (OSI were found prominently higher after smoking a water pipe for the group of water-pipe smokers than for the control group. Conclusions: This study has shown that water-pipe smoking leads to deterioration in pulmonary function and increases oxidative stress. To the best of our knowledge this study is the only one that has shown the effect of water-pipe smoking on oxidative stress. More studies must be planned to show the side effects of water-pipe habit and protective policies should be planned especially for young people in Europe. Int J Occup Med Environ Health 2017;30(5:731

  1. Investigation of arsenic removal in batch wise water treatments by means of sequential hydride generation flow injection analysis.

    Science.gov (United States)

    Toda, Kei; Takaki, Mari; Hashem, Md Abul

    2008-08-01

    Arsenic water pollution is a big issue worldwide. Determination of inorganic arsenic in each oxidation state is important because As(III) is much more toxic than As(V). An automated arsenic measurement system was developed based on complete vaporization of As by a sequential procedure and collection/preconcentration of the vaporized AsH(3), which was subsequently measured by a flow analysis. The automated sensitive method was applied to monitoring As(III) and As(V) concentrations in contaminated water standing overnight. Behaviors of arsenics were investigated in different conditions, and unique time dependence profiles were obtained. For example, in the standing of anaerobic water samples, the As(III) concentration immediately began decreasing whereas dead time was observed in the removal of As(V). In normal groundwater conditions, most arsenic was removed from the water simply by standing overnight. To obtain more effective removal, the addition of oxidants and use of steel wools were investigated. Simple batch wise treatments of arsenic contaminated water were demonstrated, and detail of the transitional changes in As(III) and As(V) were investigated.

  2. Degradation of azo dyes by sequential Fenton's oxidation and aerobic biological treatment

    International Nuclear Information System (INIS)

    Tantak, Nilesh P.; Chaudhari, Sanjeev

    2006-01-01

    A two stage sequential Fenton's oxidation followed by aerobic biological treatment train was used to achieve decolorization and to enhance mineralization of azo dyes, viz. Reactive Black 5 (RB5), Reactive Blue 13 (RB13), and Acid Orange 7 (AO7). In the first stage, Fenton's oxidation process was used while in the second stage aerobic sequential batch reactors (SBRs) were used as biological process. Study was done to evaluate effect of pH on Fenton's oxidation process. Results reveal that pH 3 was optimum pH for achieving decolorization and dearomatization of dyes by Fenton's process. Degradation of dye was assessed by COD reduction and reduction in aromatic amines (naphthalene chromophores) which was measured by reduction in absorbance at 200 nm. More than 95% of color was removed with Fenton's oxidation process in all dyes. In overall treatment train 81.95, 85.57, and 77.83% of COD reduction was achieved in RB5, RB13, and AO7 dyes, respectively. In the Fenton's oxidation process 56, 24.5, and 80% reduction in naphthalene group was observed in RB5, RB13, and AO7, respectively, which further increased to 81.34, 68.73, and 92% after aerobic treatment. Fenton's oxidation process followed by aerobic SBRs treatment sequence seems to be viable method for achieving significant degradation of azo dye

  3. Amagnetic field-enhanced filtration/sorption Device and its potential for inexpensive water and wastewater treatment

    International Nuclear Information System (INIS)

    Navratil, J.D.

    2000-01-01

    A magnetic field-enhanced filtration/sorption device is described for removal of radioactive and heavy metals from water and wastewater. The device consists of a column of supported magnetite surrounded by a movable permanent magnet. The mineral magnetite, or synthetically prepared iron ferrite (Fe O Fe 2 O 3 ), is typically supported on various materials to permit adequate water passage through the column. In the presence of the external magnetic field, enhanced capacity was observed in using supported magnetite for removal of actinides and heavy metals from wastewater. The enhanced capacity is primarily due to magnetic filtration of colloidal and submicron particles along with some complex and ion exchange sorption mechanisms. The loaded magnetite can easily be regenerated by the removal of the magnetic field and use of a regenerating solution. This paper will review previous work on the use of iron oxides for wastewater treatment and discuss the development and potential of the magnetic filtration/sorption process for water and wastewater treatment

  4. Evaluation of Water Treatment Problems: Case Study of Maiduguri Water Treatment Plant (MWTP and Maiduguri Environs

    Directory of Open Access Journals (Sweden)

    M. N. Idris

    2017-10-01

    Full Text Available Water remains the most useful universal solvent to human being and other animals, because of its derivative importance. However, effort to improve on raw water treatment would continue to be a subject of concern, because the process procedures are been violated or not properly upheld. This study was carried out in order to identify peculiar problems associate with water treatment at the Maiduguri Water Treatment Plant (MWTP. This research study was based on prompt time-schedules and plant site-visits, interviewed questions were made and accessing the technology adopted in the process stages. Analytical data were obtained through the use of sampling bottles, camera, record sheets and other necessary laboratory equipment. The analysis showed that treated water contained excess chlorine and aluminum with 1.10mg/l and 0.68mg/l respectively. From this study, the following are the root causes: poor facility lay out, poor organizational and functional structures, wear of pump impellers and surface deterioration in the transmission line, lack of calibration test, constant head system not operation properly, lack of jar test conduction, improper maintenance of filter system, and the use of chemical coagulant. Inferences were made at the end of the research to enhance process efficiency, healthier and more economical treatment MWTP.

  5. Design and operational parameters of transportable supercritical water oxidation waste destruction unit

    International Nuclear Information System (INIS)

    McFarland, R.D.; Brewer, G.R.; Rofer, C.K.

    1991-12-01

    Supercritical water oxidation (SCWO) is the destruction of hazardous waste by oxidation in the presence of water at temperatures and pressures above its critical point. A 1 gal/h SCWO waste destruction unit (WDU) has been designed, built, and operated at Los Alamos National Laboratory. This unit is transportable and is intended to demonstrate the SCWO technology on wastes at Department of Energy sites. This report describes the design of the WDU and the preliminary testing phase leading to demonstration

  6. Kinetics of Chronic Oxidation of NBG-17 Nuclear Graphite by Water Vapor

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burchell, Timothy D [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mee, Robert [Univ. of Tennessee, Knoxville, TN (United States)

    2015-05-01

    This report presents the results of kinetic measurements during accelerated oxidation tests of NBG-17 nuclear graphite by low concentration of water vapor and hydrogen in ultra-high purity helium. The objective is to determine the parameters in the Langmuir-Hinshelwood (L-H) equation describing the oxidation kinetics of nuclear graphite in the helium coolant of high temperature gas-cooled reactors (HTGR). Although the helium coolant chemistry is strictly controlled during normal operating conditions, trace amounts of moisture (predictably < 0.2 ppm) cannot be avoided. Prolonged exposure of graphite components to water vapor at high temperature will cause very slow (chronic) oxidation over the lifetime of graphite components. This behavior must be understood and predicted for the design and safe operation of gas-cooled nuclear reactors. The results reported here show that, in general, oxidation by water of graphite NBG-17 obeys the L-H mechanism, previously documented for other graphite grades. However, the characteristic kinetic parameters that best describe oxidation rates measured for graphite NBG-17 are different than those reported previously for grades H-451 (General Atomics, 1978) and PCEA (ORNL, 2013). In some specific conditions, certain deviations from the generally accepted L-H model were observed for graphite NBG-17. This graphite is manufactured in Germany by SGL Carbon Group and is a possible candidate for the fuel elements and reflector blocks of HTGR.

  7. Fixed-biofilm reactors applied to waste water treatment and aquacultural water recirculating systems

    NARCIS (Netherlands)

    Bovendeur, J.

    1989-01-01

    Fixed-biofilm waste water treatment may be regarded as one of the oldest engineered biological waste water treatment methods. With the recent introduction of modern packing materials, this type of reactor has received a renewed impuls for implementation in a wide field of water treatment.

    In

  8. Enhancement of Antioxidant Mechanisms and Reduction of Oxidative Stress in Chickens after the Administration of Drinking Water Enriched with Polyphenolic Powder from Olive Mill Waste Waters

    Directory of Open Access Journals (Sweden)

    Aliki Papadopoulou

    2017-01-01

    Full Text Available The aim of the study was to examine the effects of a polyphenolic powder from olive mill wastewater (OMWW administered through drinking water, on chickens’ redox status. Thus, 75 chickens were divided into three groups. Group A was given just drinking water, while groups B and C were given drinking water containing 20 and 50 μg/ml of polyphenols, respectively, for 45 days. The antioxidant effects of the polyphenolic powder were assessed by measuring oxidative stress biomarkers in blood after 25 and 45 days of treatment. These markers were total antioxidant capacity (TAC, protein carbonyls (CARB, thiobarbituric acid reactive species (TBARS and superoxide dismutase activity (SOD in plasma, and glutathione (GSH and catalase activity in erythrocytes. The results showed that CARB and TBARS were decreased significantly in groups B and C, and SOD decreased in group B compared to that in group A. TAC was increased significantly in group C and GSH was increased in group B, while catalase activity was increased in groups B and C compared to that in group A. In conclusion, this is the first study showing that supplementation of chickens with polyphenols from OMWW through drinking water enhanced their antioxidant mechanisms and reduced oxidative stress-induced damage.

  9. Enhancement of Antioxidant Mechanisms and Reduction of Oxidative Stress in Chickens after the Administration of Drinking Water Enriched with Polyphenolic Powder from Olive Mill Waste Waters.

    Science.gov (United States)

    Papadopoulou, Aliki; Petrotos, Konstantinos; Stagos, Dimitrios; Gerasopoulos, Konstantinos; Maimaris, Antonios; Makris, Haralampos; Kafantaris, Ioannis; Makri, Sotiria; Kerasioti, Efthalia; Halabalaki, Maria; Brieudes, Vincent; Ntasi, Georgia; Kokkas, Stylianos; Tzimas, Pavlos; Goulas, Panagiotis; Zakharenko, Alexander M; Golokhvast, Kirill S; Tsatsakis, Aristidis; Kouretas, Demetrios

    2017-01-01

    The aim of the study was to examine the effects of a polyphenolic powder from olive mill wastewater (OMWW) administered through drinking water, on chickens' redox status. Thus, 75 chickens were divided into three groups. Group A was given just drinking water, while groups B and C were given drinking water containing 20 and 50  μ g/ml of polyphenols, respectively, for 45 days. The antioxidant effects of the polyphenolic powder were assessed by measuring oxidative stress biomarkers in blood after 25 and 45 days of treatment. These markers were total antioxidant capacity (TAC), protein carbonyls (CARB), thiobarbituric acid reactive species (TBARS) and superoxide dismutase activity (SOD) in plasma, and glutathione (GSH) and catalase activity in erythrocytes. The results showed that CARB and TBARS were decreased significantly in groups B and C, and SOD decreased in group B compared to that in group A. TAC was increased significantly in group C and GSH was increased in group B, while catalase activity was increased in groups B and C compared to that in group A. In conclusion, this is the first study showing that supplementation of chickens with polyphenols from OMWW through drinking water enhanced their antioxidant mechanisms and reduced oxidative stress-induced damage.

  10. Possibilities of practical usage of dispersed aluminim oxidation by liquid water

    Science.gov (United States)

    Larichev, M. N.; Laricheva, O. O.; Shaitura, N. S.; Shkolnikov, E. I.

    2012-12-01

    The goal of this work is to show the possibility of practical usage of the environmentally pure oxidation process of preliminarily dispersed aluminum (aluminum powders of the ASD or PAD grade according to TU (Technical Specifications) 48-5-226-87, which are serially produced in industry) with liquid water in order to obtain gaseous hydrogen in volumes sufficient to provide the operation of energizers based on airhydrogen fuel cells (AHFC) for portable and stationary devices (up to 3 kW). It is shown that the synthesis of aluminum oxides-hydroxides with the specified phase and chemical compositions as well as the particle shape and size can be provided simultaneously with producing commercial hydrogen. The practical usage of hydrogen, which is formed in the oxidation reaction of metallic aluminum with liquid water at pressures close to atmospheric (particularly, to service AHFCs), requires reaction intensification to increase the oxidation rate of aluminum. In this work, we considered the aspects of practical implementation of thermal, ultrasonic, and chemical activation as well as their combinations for this purpose. As the chemical activator of oxidation, we used the additives of calcium oxide (<5% of the mass of oxidized aluminum). Application of each activation method affects the phase and chemical compositions as well as the structure of formed aluminum hydroxides, which provides the possibility of their reproducible production. Thus, simultaneously with the production of commercial hydrogen, solid oxidation products satisfying the needs of industry in aluminum oxides and having the specified composition, purity, and particle shape and size can be synthesized. The acquired experimental results and elements of the design of specially developed industrial apparatuses, which were used when performing this work, can be applied when designing the model of the hydrogen generator—the prototype of the hydrogen generator for portable and stationary devices or devices

  11. Improved Energy Recovery by Anaerobic Grey Water Sludge Treatment with Black Water

    Directory of Open Access Journals (Sweden)

    Taina Tervahauta

    2014-08-01

    Full Text Available This study presents the potential of combining anaerobic grey water sludge treatment with black water in an up-flow anaerobic sludge blanket (UASB reactor to improve energy recovery within source-separated sanitation concepts. Black water and the mixture of black water and grey water sludge were compared in terms of biochemical methane potential (BMP, UASB reactor performance, chemical oxygen demand (COD mass balance and methanization. Grey water sludge treatment with black water increased the energy recovery by 23% in the UASB reactor compared to black water treatment. The increase in the energy recovery can cover the increased heat demand of the UASB reactor and the electricity demand of the grey water bioflocculation system with a surplus of 0.7 kWh/cap/y electricity and 14 MJ/cap/y heat. However, grey water sludge introduced more heavy metals in the excess sludge of the UASB reactor and might therefore hinder its soil application.

  12. Nitrification and the ammonia-oxidizing communities in the central Baltic Sea water column

    Science.gov (United States)

    Jäntti, Helena; Ward, Bess B.; Dippner, Joachim W.; Hietanen, Susanna

    2018-03-01

    The redoxclines that form between the oxic and anoxic water layers in the central Baltic Sea are sites of intensive nitrogen cycling. To gain better understanding of nitrification, we measured the biogeochemical properties along with potential nitrification rates and analyzed the assemblages of ammonia-oxidizing bacteria and archaea using functional gene microarrays. To estimate nitrification in the entire water column, we constructed a regression model for the nitrification rates and applied it to the conditions prevailing in the area in 2008-2012. The highest ammonia oxidation rates were found in a thin layer at the top of the redoxcline and the rates quickly decreased below detection limit when oxygen was exhausted. This is probably because extensive suboxic layers, which are known to harbor pelagic nitrification, are formed only for short periods after inflows in the Baltic Sea. The nitrification rates were some of the highest measured in the water columns, but the thickness of the layer where conditions were favorable for nitrification, was very small and it remained fairly stable between years. However, the depth of the nitrification layer varied substantially between years, particularly in the eastern Gotland Basin (EGB) due to turbulence in the water column. The ammonia oxidizer communities clustered differently between the eastern and western Gotland Basin (WGB) and the composition of ammonia-oxidizing assemblages correlated with the environmental variables. The ammonia oxidizer community composition was more even in the EGB, which may be related to physical instability of the redoxcline that does not allow predominance of a single archetype, whereas in the WGB, where the position of the redoxcline is more constant, the ammonia-oxidizing community was less even. Overall the ammonia-oxidizing communities in the Baltic Sea redoxclines were very evenly distributed compared to other marine environments where microarrays have been applied previously.

  13. Electrochemical Water Oxidation and Stereoselective Oxygen Atom Transfer Mediated by a Copper Complex.

    Science.gov (United States)

    Kafentzi, Maria-Chrysanthi; Papadakis, Raffaello; Gennarini, Federica; Kochem, Amélie; Iranzo, Olga; Le Mest, Yves; Le Poul, Nicolas; Tron, Thierry; Faure, Bruno; Simaan, A Jalila; Réglier, Marius

    2018-04-06

    Water oxidation by copper-based complexes to form dioxygen has attracted attention in recent years, with the aim of developing efficient and cheap catalysts for chemical energy storage. In addition, high-valent metal-oxo species produced by the oxidation of metal complexes in the presence of water can be used to achieve substrate oxygenation with the use of H 2 O as an oxygen source. To date, this strategy has not been reported for copper complexes. Herein, a copper(II) complex, [(RPY2)Cu(OTf) 2 ] (RPY2=N-substituted bis[2-pyridyl(ethylamine)] ligands; R=indane; OTf=triflate), is used. This complex, which contains an oxidizable substrate moiety (indane), is used as a tool to monitor an intramolecular oxygen atom transfer reaction. Electrochemical properties were investigated and, upon electrolysis at 1.30 V versus a normal hydrogen electrode (NHE), both dioxygen production and oxygenation of the indane moiety were observed. The ligand was oxidized in a highly diastereoselective manner, which indicated that the observed reactivity was mediated by metal-centered reactive species. The pH dependence of the reactivity was monitored and correlated with speciation deduced from different techniques, ranging from potentiometric titrations to spectroscopic studies and DFT calculations. Water oxidation for dioxygen production occurs at neutral pH and is probably mediated by the oxidation of a mononuclear copper(II) precursor. It is achieved with a rather low overpotential (280 mV at pH 7), although with limited efficiency. On the other hand, oxygenation is maximum at pH 8-8.5 and is probably mediated by the electrochemical oxidation of an antiferromagnetically coupled dinuclear bis(μ-hydroxo) copper(II) precursor. This constitutes the first example of copper-centered oxidative water activation for a selective oxygenation reaction. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Gold-Catalyzed Aerobic Oxidation of 5-Hydroxymethylfurfural in Water at Ambient Temperature

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Woodley, John

    2009-01-01

    The aerobic oxidation of 5-hydroxymethylfurfural, a versatile biomass-derived chemical, is examined in water with a titania-supported gold-nanoparticle catalyst at ambient temperature (30 degrees C). The selectivity of the reaction towords 2,5-furandicarboxylic acid and the intermediate oxidation...

  15. Sensitization of Nanocrystalline Metal Oxides with a Phosphonate-Functionalized Perylene Diimide for Photoelectrochemical Water Oxidation with a CoOx Catalyst.

    Science.gov (United States)

    Kirner, Joel T; Finke, Richard G

    2017-08-23

    A planar organic thin film composed of a perylene diimide dye (N,N'-bis(phosphonomethyl)-3,4,9,10-perylenediimide, PMPDI) with photoelectrochemically deposited cobalt oxide (CoO x ) catalyst was previously shown to photoelectrochemically oxidize water (DOI: 10.1021/am405598w). Herein, the same PMPDI dye is studied for the sensitization of different nanostructured metal oxide (nano-MO x ) films in a dye-sensitized photoelectrochemical cell architecture. Dye adsorption kinetics and saturation decreases in the order TiO 2 > SnO 2 ≫ WO 3 . Despite highest initial dye loading on TiO 2 films, photocurrent with hydroquinone (H 2 Q) sacrificial reductant in pH 7 aqueous solution is much higher on SnO 2 films, likely due to a higher driving force for charge injection into the more positive conduction band energy of SnO 2 . Dyeing conditions and SnO 2 film thickness were subsequently optimized to achieve light-harvesting efficiency >99% at the λ max of the dye, and absorbed photon-to-current efficiency of 13% with H 2 Q, a 2-fold improvement over the previous thin-film architecture. A CoO x water-oxidation catalyst was photoelectrochemically deposited, allowing for photoelectrochemical water oxidation with a faradaic efficiency of 31 ± 7%, thus demonstrating the second example of a water-oxidizing, dye-sensitized photoelectrolysis cell composed entirely of earth-abundant materials. However, deposition of CoO x always results in lower photocurrent due to enhanced recombination between catalyst and photoinjected electrons in SnO 2 , as confirmed by open-circuit photovoltage measurements. Possible future studies to enhance photoanode performance are discussed, including alternative catalyst deposition strategies or structural derivatization of the perylene dye.

  16. Hot water extraction with in situ wet oxidation: Kinetics of PAHs removal from soil

    International Nuclear Information System (INIS)

    Dadkhah, Ali A.; Akgerman, Aydin

    2006-01-01

    Finding environmentally friendly and cost-effective methods to remediate soils contaminated with polycyclic aromatic hydrocarbons (PAHs) is currently a major concern of researchers. In this study, a series of small-scale semi-continuous extractions - with and without in situ wet oxidation - were performed on soils polluted with PAHs, using subcritical water (i.e. liquid water at high temperatures and pressures, but below the critical point) as the removal agent. Experiments were performed in a 300 mL reactor using an aged soil sample. To find the desorption isotherms and oxidation reaction rates, semi-continuous experiments with residence times of 1 and 2 h were performed using aged soil at 250 deg. C and hydrogen peroxide as oxidizing agent. In all combined extraction and oxidation flow experiments, PAHs in the remaining soil after the experiments were almost undetectable. In combined extraction and oxidation no PAHs could be detected in the liquid phase after the first 30 min of the experiments. Based on these results, extraction with hot water, if combined with oxidation, should reduce the cost of remediation and can be used as a feasible alternative technique for remediating contaminated soils and sediments

  17. Coagulation effectiveness of graphene oxide for the removal of turbidity from raw surface water.

    Science.gov (United States)

    Aboubaraka, Abdelmeguid E; Aboelfetoh, Eman F; Ebeid, El-Zeiny M

    2017-08-01

    This study presents the performance of graphene oxide (GO) as a coagulant in turbidity removal from naturally and artificially turbid raw surface water. GO is considered an excellent alternative to alum, the more common coagulant used in water treatment processes, to reduce the environmental release of aluminum. Effects of GO dosage, pH, and temperature on its coagulation ability were studied to determine the ideal turbidity removal conditions. The turbidity removal was ≥95% for all levels of turbid raw surface water (20, 100, and 200 NTU) at optimum conditions. The role of alkalinity in inducing turbidity removal by GO coagulation was much more pronounced upon using raw surface water samples compared with that using artificially turbid deionized water samples. Moreover, GO demonstrated high-performance removal of biological contaminants such as algae, heterotrophic bacteria, and fecal coliform bacteria by 99.0%, 98.8% and 96.0%, respectively, at a dosage of 40 mg/L. Concerning the possible environmental release of GO into the treated water following filtration process, there was no residual GO in a wide range of pH values. The outcomes of the study highlight the excellent coagulation performance of GO for the removal of turbidity and biological contaminants from raw surface water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The Effect of Water Chemistry on the Removal of Arsenic from Drinking Water During Iron Removal Treatment

    Science.gov (United States)

    This research investigates the effects of water chemistry, oxidant type and concentration on the removal of iron and arsenic from drinking water. The research will be conducted using one of the National Risk Management Research Laboratory’s Water Supply and Water Resources Divisi...

  19. Report on research cooperation for bio-aided treatment of waste water from pits, conducted in FY1997; 1997 nendo bio riyo ni yoru kohaisui shori gijutsu ni kansuru kenkyu kyoryoku hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    This research cooperation promotion project was implemented to develop techniques for preventing water pollution by waste water from pits in mines in China and thereby contributing to environmental preservation by studying to select optimum bacteria, culture the bacteria for high-efficient oxidation of iron, efficiently remove heavy metals from waste water, develop waste water treatment techniques with the aid of the iron-oxidizing bacteria, suitable for the mines in China, and develop techniques for recovering useful resources. The bio-aided waste water treatment process is a suitable method for treating waste water discharged from mining pits, in which ferrous iron present in waste water is oxidized with the aid of iron-oxidizing bacteria growing with ferrous ion as the energy source into ferric iron, which is precipitated at a low pH and removed in the presence of inexpensive calcium carbonate as the neutralizer. The pilot plant has been operating smoothly in a mode to treat waste water discharged from mining pits in Wushan Mine, almost satisfying the targets of treated water properties, i.e., pH: 0.5 or less, Cu: less than 0.5, Zn: less than 2.0, Pb: less than 1.0, Cd: less than 0.1, As: less than 0.5, Mn: less than 2.0, and SS: less than 70, all in mg/L except for pH. (NEDO)

  20. Waste Water Treatment Unit

    International Nuclear Information System (INIS)

    Ramadan, A.E.K.

    2004-01-01

    A wastewater treatment plant to treat both the sanitary and industrial effluent originated from process, utilities and off site units of the refinery is described. The purpose is to obtain at the end of the treatment plant, a water quality that is in compliance with contractual requirements and relevant environmental regulations. first treatment (pretreatment). Primary de-oiling, Equalization, Neutralization, Secondary de-oiling. Second treatment (Biological), The mechanism of BOD removal, Biological flocculation, Nutrient requirements, Nitrification, De-nitrification, Effect of temperature, Effect of ph, Toxicity

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

    Energy Technology Data Exchange (ETDEWEB)

    Huanosta-Gutierrez, T. [Instituto de Ingenieria, Coordinacion de Ingenieria Ambiental, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, Coyoacan 04510, Mexico, D.F. (Mexico); Dantas, Renato F., E-mail: falcao@angel.qui.ub.es [Departament d' Enginyeria Quimica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Ramirez-Zamora, R.M. [Instituto de Ingenieria, Coordinacion de Ingenieria Ambiental, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, Coyoacan 04510, Mexico, D.F. (Mexico); Esplugas, S. [Departament d' Enginyeria Quimica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer We evaluate the use of an industrial residue (copper slag) as catalyst in water treatment. Black-Right-Pointing-Pointer The copper slag was effective to remove organic pollutants (phenol) from water. Black-Right-Pointing-Pointer During experimentation, Cu and Fe leaching were not higher than the acceptable levels. Black-Right-Pointing-Pointer Slag/H{sub 2}O{sub 2}/UV and slag/H{sub 2}O{sub 2} treatments promoted biodegradability increment of the contaminated water. Black-Right-Pointing-Pointer The control of the reaction time would minimize the environmental impact of the produced effluents in terms of acute toxicity. - Abstract: 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{sub 2}O{sub 2} (slag/H{sub 2}O{sub 2}) and H{sub 2}O{sub 2}/UV (slag/H{sub 2}O{sub 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{sub 2}O{sub 2}/UV and slag/H{sub 2}O{sub 2} treatments have favored biodegradability increment along the reaction time. Nevertheless, the irradiated method achieved higher values of the biodegradability indicator (BOD{sub 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.

  2. Modeling Manganese Sorption and Surface Oxidation During Filtration

    OpenAIRE

    Bierlein, Kevin Andrew

    2012-01-01

    Soluble manganese (Mn) is a common contaminant in drinking water sources. High levels of Mn can lead to aesthetic water quality problems, necessitating removal of Mn during treatment to minimize consumer complaints. Mn may be removed during granular media filtration by the â natural greensand effect,â in which soluble Mn adsorbs to manganese oxide-coated (MnOx(s)) media and is then oxidized by chlorine, forming more manganese oxide. This research builds on a previous model developed by Mer...

  3. DETERMINATION OF THE RATES AND PRODUCTS OF FERROUS IRON OXIDATION IN ARSENIC-CONTAMINATED POND WATER.

    Science.gov (United States)

    Dissolved ferrous iron and arsenic in the presence of insufficient oxygenated ground water is released into a pond. When the mixing of ferrous iron and oxygenated water within the pond occurs, the ferrous iron is oxidized and precipitated as an iron oxide. Groups of experiments...

  4. Biological iron(II) oxidation as pre-treatment to limestone neutralisation of acid water

    CSIR Research Space (South Africa)

    Maree

    1998-01-01

    Full Text Available at investigating the effect of surface area of the medium that supports bacterial growth on the rate of biological iron (II) oxidation. The study showed that the biological iron (II) oxidation rate is directly proportional to the square root of the medium specific...

  5. Indium-tin oxide surface treatments: Effects on the performance of liquid crystal devices

    International Nuclear Information System (INIS)

    Abderrahmen, A.; Romdhane, F.F.; Ben Ouada, H.; Gharbi, A.

    2006-01-01

    In this work, we investigate the effect of indium tin oxide (ITO) substrate cleaning on the surface properties. Wettability technique was used to measure the contact angle and the surface energy of the different treated ITO substrates. It is found that treatment with the methanol without dehydration gives the lowest water contact angle (most hydrophilic surface) and the highest surface energy compared to other solvents. This result was confirmed by impedance measurements performed on nematic liquid crystal cells with ITO electrodes. Indeed, we check the decrease of ionic entities in the interface ITO/liquid crystal. The polarity and dielectric parameters of the used solvents explain the obtained results

  6. Indium-tin oxide surface treatments: Effects on the performance of liquid crystal devices

    Energy Technology Data Exchange (ETDEWEB)

    Abderrahmen, A. [Laboratoire de physique et chimie des interfaces, Faculte des sciences, 5000, Monastir (Tunisia)]. E-mail: asma_abderrahmen@yahoo.fr; Romdhane, F.F. [Laboratoire de la matiere molle, Faculte des sciences, Tunis (Tunisia); Ben Ouada, H. [Laboratoire de physique et chimie des interfaces, Faculte des sciences, 5000, Monastir (Tunisia); Gharbi, A. [Laboratoire de la matiere molle, Faculte des sciences, Tunis (Tunisia)

    2006-03-15

    In this work, we investigate the effect of indium tin oxide (ITO) substrate cleaning on the surface properties. Wettability technique was used to measure the contact angle and the surface energy of the different treated ITO substrates. It is found that treatment with the methanol without dehydration gives the lowest water contact angle (most hydrophilic surface) and the highest surface energy compared to other solvents. This result was confirmed by impedance measurements performed on nematic liquid crystal cells with ITO electrodes. Indeed, we check the decrease of ionic entities in the interface ITO/liquid crystal. The polarity and dielectric parameters of the used solvents explain the obtained results.

  7. Demonstration of high-performance p-type tin oxide thin-film transistors using argon-plasma surface treatments

    Science.gov (United States)

    Bae, Sang-Dae; Kwon, Soo-Hun; Jeong, Hwan-Seok; Kwon, Hyuck-In

    2017-07-01

    In this work, we investigated the effects of low-temperature argon (Ar)-plasma surface treatments on the physical and chemical structures of p-type tin oxide thin-films and the electrical performance of p-type tin oxide thin-film transistors (TFTs). From the x-ray photoelectron spectroscopy measurement, we found that SnO was the dominant phase in the deposited tin oxide thin-film, and the Ar-plasma treatment partially transformed the tin oxide phase from SnO to SnO2 by oxidation. The resistivity of the tin oxide thin-film increased with the plasma-treatment time because of the reduced hole concentration. In addition, the root-mean-square roughness of the tin oxide thin-film decreased as the plasma-treatment time increased. The p-type oxide TFT with an Ar-plasma-treated tin oxide thin-film exhibited excellent electrical performance with a high current on-off ratio (5.2 × 106) and a low off-current (1.2 × 10-12 A), which demonstrates that the low-temperature Ar-plasma treatment is a simple and effective method for improving the electrical performance of p-type tin oxide TFTs.

  8. An overview on exploration and environmental impact of unconventional gas sources and treatment options for produced water.

    Science.gov (United States)

    Silva, Tânia L S; Morales-Torres, Sergio; Castro-Silva, Sérgio; Figueiredo, José L; Silva, Adrián M T

    2017-09-15

    Rising global energy demands associated to unbalanced allocation of water resources highlight the importance of water management solutions for the gas industry. Advanced drilling, completion and stimulation techniques for gas extraction, allow more economical access to unconventional gas reserves. This stimulated a shale gas revolution, besides tight gas and coalbed methane, also causing escalating water handling challenges in order to avoid a major impact on the environment. Hydraulic fracturing allied to horizontal drilling is gaining higher relevance in the exploration of unconventional gas reserves, but a large amount of wastewater (known as "produced water") is generated. Its variable chemical composition and flow rates, together with more severe regulations and public concern, have promoted the development of solutions for the treatment and reuse of such produced water. This work intends to provide an overview on the exploration and subsequent environmental implications of unconventional gas sources, as well as the technologies for treatment of produced water, describing the main results and drawbacks, together with some cost estimates. In particular, the growing volumes of produced water from shale gas plays are creating an interesting market opportunity for water technology and service providers. Membrane-based technologies (membrane distillation, forward osmosis, membrane bioreactors and pervaporation) and advanced oxidation processes (ozonation, Fenton, photocatalysis) are claimed to be adequate treatment solutions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Self-propagating solar light reduction of graphite oxide in water

    Energy Technology Data Exchange (ETDEWEB)

    Todorova, N.; Giannakopoulou, T.; Boukos, N.; Vermisoglou, E. [Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 153 41 Attikis (Greece); Lekakou, C. [Division of Mechanical, Medical, and Aerospace Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford (United Kingdom); Trapalis, C., E-mail: c.trapalis@inn.demokritos.gr [Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 153 41 Attikis (Greece)

    2017-01-01

    Highlights: • Graphite oxide was partially reduced by solar light irradiation in water media. • No addition of catalysts nor reductive agent were used for the reduction. • Specific capacitance increased stepwise with increase of irradiation time. • Self-propagating reduction of graphene oxide by solar light is suggested. - Abstract: Graphite Oxide (GtO) is commonly used as an intermediate material for preparation of graphene in the form of reduced graphene oxide (rGO). Being a semiconductor with tunable band gap rGO is often coupled with various photocatalysts to enhance their visible light activity. The behavior of such rGO-based composites could be affected after prolonged exposure to solar light. In the present work, the alteration of the GtO properties under solar light irradiation is investigated. Water dispersions of GtO manufactured by oxidation of natural graphite via Hummers method were irradiated into solar light simulator for different periods of time without addition of catalysts or reductive agent. The FT-IR analysis of the treated dispersions revealed gradual reduction of the GtO with the increase of the irradiation time. The XRD, FT-IR and XPS analyses of the obtained solid materials confirmed the transition of GtO to rGO under solar light irradiation. The reduction of the GtO was also manifested by the CV measurements that revealed stepwise increase of the specific capacitance connected with the restoration of the sp{sup 2} domains. Photothermal self-propagating reduction of graphene oxide in aqueous media under solar light irradiation is suggested as a possible mechanism. The self-photoreduction of GtO utilizing solar light provides a green, sustainable route towards preparation of reduced graphene oxide. However, the instability of the GtO and partially reduced GO under irradiation should be considered when choosing the field of its application.

  10. Carbamazepine as a Possible Anthropogenic Marker in Water: Occurrences, Toxicological Effects, Regulations and Removal by Wastewater Treatment Technologies

    Directory of Open Access Journals (Sweden)

    Faisal I. Hai

    2018-01-01

    Full Text Available Carbamazepine (CBZ, a pharmaceutical compound, has been proposed as an anthropogenic marker to assess water quality due to its persistence in conventional treatment plants and widespread presence in water bodies. This paper presents a comprehensive literature review on sources and occurrences of CBZ in water bodies, as well as toxicological effects and regulations of the drug. Given the documented side effects of CBZ on the human body when taken medicinally, its careful monitoring in water is recommended. CBZ residues in drinking water may provide a pathway to embryos and infants via intrauterine exposure or breast-feeding, which may cause congenital malformations and/or neurodevelopmental problems over long term exposure. An in-depth technical assessment of the conventional and advanced treatment technologies revealed the inadequacy of the standalone technologies. Compared to conventional activated sludge and membrane bioreactor processes, effective removal of CBZ can be achieved by nanofiltration and reverse osmosis membranes. However, recent studies have revealed that harsh chemical cleaning, as required to mitigate membrane fouling, can often reduce the long-term removal efficiency. Furthermore, despite the efficient performance of activated carbon adsorption and advanced oxidation processes, a few challenges such as cost of chemicals and regeneration of activated carbon need to be carefully considered. The limitations of the individual technologies point to the advantages of combined and hybrid systems, namely, membrane bioreactor coupled with nanofiltration, adsorption or advanced oxidation process.

  11. The Oxidative Stress Response in Elite Water Polo Players: Effects of Genetic Background.

    Science.gov (United States)

    Vecchio, Mercurio; Currò, Monica; Trimarchi, Fabio; Naccari, Sergio; Caccamo, Daniela; Ientile, Riccardo; Barreca, Davide; Di Mauro, Debora

    2017-01-01

    Acute exercise is known to induce oxidative stress. Here we assessed the effects of gene polymorphisms SOD2 A16V, CAT -844 G>A, and GPx-1 rs1800668 C>T on oxidative stress markers in 28 elite water polo male players prior to and after a routinely programmed friendly match. The mean plasma concentrations of derivatives of reactive oxygen metabolites (dROMs), as well as lactic dehydrogenase (LDH) activity, creatine kinase (CK) activity, CK-MB, and myoglobin, were significantly increased after exercise, while blood antioxidant potential (BAP) and total free thiols were significantly decreased, compared with those measured before exercise. Advanced oxidation protein products (AOPP) were also increased after exercise but not significantly. We observed that water polo players having either AV16 or VV16 SOD genotype exhibited a significant increase of postexercise AOPP, LDH, CK, and myoglobin plasma levels in comparison with wild-type athletes. Water polo players having either CAT -844 GA or GPx1 CT genotype showed a significant increase of postexercise dROMs plasma levels and, respectively, GPx and CAT enzyme activities in comparison with wild-type subjects. These preliminary results suggest that the screening for gene variants of antioxidant enzymes could be useful to assess individual susceptibility to oxidative stress and muscle damage in water polo players.

  12. Effect of surfactant-coated iron oxide nanoparticles on the effluent water quality from a simulated sequencing batch reactor treating domestic wastewater

    International Nuclear Information System (INIS)

    Hwang, Sangchul; Martinez, Diana; Perez, Priscilla; Rinaldi, Carlos

    2011-01-01

    This study was conducted to evaluate the effect of commercially available engineered iron oxide nanoparticles coated with a surfactant (ENP Fe-surf ) on effluent water quality from a lab-scale sequencing batch reactor as a model secondary biological wastewater treatment. Results showed that ∼8.7% of ENP Fe-surf applied were present in the effluent stream. The stable presence of ENP Fe-surf was confirmed by analyzing the mean particle diameter and iron concentration in the effluent. Consequently, aqueous ENP Fe-surf deteriorated the effluent water quality at a statistically significant level (p Fe-surf would be introduced into environmental receptors through the treated effluent and could potentially impact them. - Highlights: → Surfactant-coated engineered iron oxide nanoparticles (ENP Fe-surf ) were assessed. → Effluent quality was analyzed from a sequencing batch reactor with ENP Fe-surf . → ∼8.7% of ENP Fe-surf applied was present in the effluent. → ENP Fe-surf significantly (p Fe-surf will be introduced into environmental receptors. - Stable presence of surfactant-coated engineered iron oxides nanoparticles deteriorated the effluent water quality at a statistically significant level (p < 0.05).

  13. QSAR analysis for nano-sized layered manganese-calcium oxide in water oxidation: An application of chemometric methods in artificial photosynthesis.

    Science.gov (United States)

    Shahbazy, Mohammad; Kompany-Zareh, Mohsen; Najafpour, Mohammad Mahdi

    2015-11-01

    Water oxidation is among the most important reactions in artificial photosynthesis, and nano-sized layered manganese-calcium oxides are efficient catalysts toward this reaction. Herein, a quantitative structure-activity relationship (QSAR) model was constructed to predict the catalytic activities of twenty manganese-calcium oxides toward water oxidation using multiple linear regression (MLR) and genetic algorithm (GA) for multivariate calibration and feature selection, respectively. Although there are eight controlled parameters during synthesizing of the desired catalysts including ripening time, temperature, manganese content, calcium content, potassium content, the ratio of calcium:manganese, the average manganese oxidation state and the surface of catalyst, by using GA only three of them (potassium content, the ratio of calcium:manganese and the average manganese oxidation state) were selected as the most effective parameters on catalytic activities of these compounds. The model's accuracy criteria such as R(2)test and Q(2)test in order to predict catalytic rate for external test set experiments; were equal to 0.941 and 0.906, respectively. Therefore, model reveals acceptable capability to anticipate the catalytic activity. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. A Comparison Study of the Removal of Selected Pharmaceuticals in Waters by Chemical Oxidation Treatments

    OpenAIRE

    F. Javier Benitez; Juan Luis Acero; Francisco J. Real; Gloria Roldan; Francisco Casas

    2011-01-01

    The degradation of selected pharmaceuticals in some water matrices was studied by using several chemical treatments. The pharmaceuticals selected were the beta-blocker metoprolol, the nonsteroidal anti-inflammatory naproxen, the antibiotic amoxicillin, and the analgesic phenacetin; and their degradations were conducted by using UV radiation alone, ozone, Fenton-s reagent, Fenton-like system, photo-Fenton system, and combinations of UV radiation and ozone with H2O2, TiO2, ...

  15. Waste water treatment in surface mines

    Energy Technology Data Exchange (ETDEWEB)

    Navasardyants, M A; Esipov, V Z; Ryzhkov, Yu A

    1981-01-01

    This paper evaluates problems associated with waste water from coal surface mines of the Kemerovougol' association in the Kuzbass. Waste water treatment in the Kuzbass is of major importance as the region is supplied with water from only one river, the Tom river. Water influx to Kemerovougol' surface mines in a year amounts to 136 million m/sup 3/. The water is used during technological processes, for fire fighting, and spraying to prevent dusting; the rest, about 82.1 million m/sup 3/, is discharged into surface waters. Of this amount, 25.1 million m/sup 3/ is heavily polluted water, 46.6 million m3 are polluted but within limits, and 10.4 million m/sup 3/ are characterized as relatively clean. Waste water is polluted with: suspended matters, oils and oil products, nitrates, nitrides and chlorides. Suspended matter content sometimes reaches 4,000 and 5,000 mg/l, and oil product content in water amounts to 2.17 mg/l. Water treatment in surface mines is two-staged: sumps and sedimentation tanks are used. Water with suspended matter content of 50 to 100 mg/l in winter and summer, and 200 to 250 mg/l in spring and autumn is reduced in sumps to 25 to 30 mg/l in summer and winter and to 40 to 50 mg/l in autumn and spring. During the first stage water treatment efficiency ranges from 50 to 80%. During the second stage water is collected in sedimentation tanks. It is noted that so-called secondary pollution is one of the causes of the relatively high level of suspended matter in discharged water. Water discharged from sedimentation tanks carries clay and loam particles from the bottom and walls of water tanks and channels.

  16. The effects of high-Ca hardness water treatment for secondary cooling water in HANARO

    International Nuclear Information System (INIS)

    Kang, T. J.; Park, Y. C.; Hwang, S. R.; Lim, I. C.; Choi, H. Y.

    2003-01-01

    Water-quality control of the second cooling system in HANARO has been altered from low Ca-hardness treatment to high Ca-hardness treatment since March, 2001. High Ca-hardness water treatment in HANARO is to maintain the calcium hardness around 12 by minimizing the blowdown of secondary cooling water. This paper describes the effect of cost reduction after change of water-quility treatment method. The result shows that the cost of the water could be reduced by 25% using the pond water in KAERI. The amount and cost for the chemical agent could be reduced by 40% and 10% respectively

  17. Determinants of Nitrous Oxide Emission from Agricultural Drainage Waters

    International Nuclear Information System (INIS)

    Reay, D. S.; Edwards, A. C.; Smith, K. A.

    2004-01-01

    Emissions of the powerful greenhouse gas nitrous oxide (N 2 O) from agricultural drainage waters are poorly quantified and its determinants are not fully understood. Nitrous oxide formation in agricultural soils is known to increase in response to N fertiliser application, but the response of N 2 O in field drainage waters is unknown. This investigation combined an intensive study of the direct flux of N 2 O from the surface of a fertilised barley field with measurement of dissolved N 2 O and nitrate (NO 3 ) concentrations in the same field's drainage waters. Dissolved N 2 O in drainage waters showed a clear response to field N fertilisation, following an identical pattern to direct N 2 O flux from the field surface. The range in N 2 O concentrations between individual field drains sampled on the same day was large, indicating considerable spatial variability exists at the farm scale. A consistent pattern of very rapid outgassing of the dissolved N 2 O in open drainage ditches was accentuated at a weir, where increased turbulence led to a clear drop in dissolved N 2 O concentration. This study underlines the need for carefully planned sampling campaigns wherever whole farm or catchment N 2 O emission budgets are attempted. It adds weight to the argument for the downward revision of the IPCC emission factor (EF 5 -g) for NO 3 in drainage waters

  18. Determinants of nitrous oxide emission from agricultural drainage waters

    International Nuclear Information System (INIS)

    Reay, D. S.; Edwards, A. C.; Smith, K. A.

    2005-01-01

    Emissions of the powerful greenhouse gas nitrous oxide (N 2 O) from agricultural drainage waters are poorly quantified and its determinants are not fully understood. Nitrous oxide formation in agricultural soils is known to increase in response to N fertiliser application, but the response of N 2 O in field drainage waters is unknown. This investigation combined an intensive study of the direct flux of N 2 O from the surface of a fertilised barley field with measurement of dissolved N 2 O and nitrate (NO 3 ) concentrations in the same field's drainage waters. Dissolved N 2 O in drainage waters showed a clear response to field N fertilisation, following an identical pattern to direct N 2 O flux from the field surface. The range in N 2 O concentrations between individual field drains sampled on the same day was large, indicating considerable spatial variability exists at the farm scale. A consistent pattern of very rapid outgassing of the dissolved N 2 O in open drainage ditches was accentuated at a weir, where increased turbulence led to a clear drop in dissolved N 2 O concentration. This study underlines the need for carefully planned sampling campaigns wherever whole farm or catchment N 2 O emission budgets are attempted. It adds weight to the argument for the downward revision of the IPCC emission factor (EF 5 -g) for NO 3 in drainage waters

  19. Treatment with glial derived neurotropic factor (GDNF attenuates oxidative damages of spinal

    Directory of Open Access Journals (Sweden)

    Tao Li

    2016-05-01

    Full Text Available Spinal cord injury (SCI is a serious and debilitating issue being suffered by wide population worldwide. Extensive treatment approaches have been tested and being verified for their efficacy. Owing to the nature of central nervous system (CNS, the resident stem cells would be triggered in response to any sort of trauma with nerve factors as their communication signals. Apart from physical injuries, damages due to oxidative stress also need to be addressed while CNS repair mechanism takes place. This study looks at the potential of glial derived nerve factor (GDNF in addressing the SCI in regard to oxidative damages. A total of 60 Wistar rats were clustered into five groups and GDNF at various concentrations was tested in each group. Assessments in terms of oxidative stress parameters were noted and analyzed accordingly. It was noted that GDNF had reduced oxidative damages and increased the levels of anti-oxidants in dose-dependent manner (p < 0.05. Though treatment with 10 mg/mL and 20 mg/mL showed significant changes as compared to control group, these treatment modalities remained insignificant among each other. In conclusion, we demonstrated that GDNF exerted a neuro-protective effect on CNS by inducing anti-oxidants and reducing the levels of oxidative stress in SCI induced rat models.

  20. Graphene oxide papers with high water adsorption capacity for air dehumidification.

    Science.gov (United States)

    Liu, Renlong; Gong, Tao; Zhang, Kan; Lee, Changgu

    2017-08-29

    Graphene oxide (GO) has shown a high potential to adsorb and store water molecules due to the oxygen-containing functional groups on its hydrophilic surface. In this study, we characterized the water absorbing properties of graphene oxide in the form of papers. We fabricated three kinds of graphene oxide papers, two with rich oxygen functional groups and one with partial chemical reduction, to vary the oxygen/carbon ratio and found that the paper with high oxygen content has higher moisture adsorption capability. For the GO paper with reduction, the overall moisture absorbance was reduced. However, the absorbance at high humidity was significantly improved due to direct formation of multilayer water vapor in the system, which derived from the weak interaction between the adsorbent and the adsorbate. To demonstrate one application of GO papers as a desiccant, we tested grape fruits with and without GO paper. The fruits with a GO paper exhibited longer-term preservation with delayed mold gathering because of desiccation effect from the paper. Our results suggest that GO will find numerous practical applications as a desiccant and is a promising material for moisture desiccation and food preservation.