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Sample records for alkaline water electrolysis

  1. Heavy water production by alkaline water electrolysis

    International Nuclear Information System (INIS)

    Several heavy water isotope production processes are reported in literature. Water electrolysis in combination with catalytic exchange CECE process is considered as a futuristic process to increase the throughput and reduce the cryogenic distillation load but the application is limited due to the high cost of electricity. Any improvement in the efficiency of electrolyzers would make this process more attractive. The efficiency of alkaline water electrolysis is governed by various phenomena such as activation polarization, ohmic polarization and concentration polarization in the cell. A systematic study on the effect of these factors can lead to methods for improving the efficiency of the electrolyzer. A bipolar and compact type arrangement of the alkaline water electrolyzer leads to increased efficiency and reduced inventory in comparison to uni-polar tank type electrolyzers. The bipolar type arrangement is formed when a number of single cells are stacked together. Although a few experimental studies have been reported in the open literature, CFD simulation of a bipolar compact alkaline water electrolyzer with porous electrodes is not readily available.The principal aim of this study is to simulate the characteristics of a single cell compact electrolyzer unit. The simulation can be used to predict the Voltage-Current Density (V-I) characteristics, which is a measure of the efficiency of the process.The model equations were solved using COMSOL multi-physics software. The simulated V-I characteristic is compared with the experimental data

  2. Development of Hydrogen Electrodes for Alkaline Water Electrolysis

    DEFF Research Database (Denmark)

    Kjartansdóttir, Cecilía Kristín

    gas based infrastructure. Alkaline water electrolysis (AWE) is the current standard (stat of the art) for industrial large-scale water electrolysis systems. One of the main criteria for industrial AWE is efficient and durable electrodes. The aim of the present PhD study was to develop electrode...... nickel hydrides in electrode metal lattice. The material degradation was considerably more severe at the anode compared to the cathode. The durability single-cell measurements indicate no deactivation of electrodes after shut-downs. Microstructure investigations on the PVD Al-Ni diffusion couples at 610......Ni3 phase. The diffusion mechanism can be the key to good properties of the developed PVD Al/Ni electrodes. Electrodes produced with shorter time of diffusion, 10-30 minutes, are found to be more prone to alkaline aluminium leaching and only 4-5 wt.% of aluminium residue is found in the leached...

  3. Anodes for alkaline electrolysis

    Science.gov (United States)

    Soloveichik, Grigorii Lev

    2011-02-01

    A method of making an anode for alkaline electrolysis cells includes adsorption of precursor material on a carbonaceous material, conversion of the precursor material to hydroxide form and conversion of precursor material from hydroxide form to oxy-hydroxide form within the alkaline electrolysis cell.

  4. Novel homogeneous anion-selective membranes for alkaline water electrolysis

    Czech Academy of Sciences Publication Activity Database

    Hnát, J.; Schauer, Jan; Paidar, M.; Bouzek, K.

    Praha : Orgit, 2012. s. 116-117. ISBN 978-80-905035-2-6. [Electromembrane Processes and Materials - ELMEMPRO 2012, Satellite Meeting of The International Society of Electrochemistry Annual Meeting /63./. 26.08.2012-29.08.2012, Český Krumlov] Institutional support: RVO:61389013 Keywords : membranes * water electrolysis Subject RIV: CD - Macromolecular Chemistry

  5. Stainless steel anodes for alkaline water electrolysis and methods of making

    Science.gov (United States)

    Soloveichik, Grigorii Lev

    2014-01-21

    The corrosion resistance of stainless steel anodes for use in alkaline water electrolysis was increased by immersion of the stainless steel anode into a caustic solution prior to electrolysis. Also disclosed herein are electrolyzers employing the so-treated stainless steel anodes. The pre-treatment process provides a stainless steel anode that has a higher corrosion resistance than an untreated stainless steel anode of the same composition.

  6. Properties of novel anion selective material with DABCO functional groups for alkaline water electrolysis

    Czech Academy of Sciences Publication Activity Database

    Hnát, J.; Žitka, Jan; Paidar, M.; Bouzek, K.

    Prague: University of Chemistry and Technology, Czech Hydrogen Technology Platform, 2015 - (Bouzek, K.; Doucek, A.). s. 28 ISBN 978-80-7080-920-4. [International Conference on Hydrogen Technologies /6./ - Hydrogen Days 2015. 18.03.2015-20.03.2015, Prague] Institutional support: RVO:61389013 Keywords : alkaline water electrolysis * anion selective polymer electrolyte * zero-gap arrangement Subject RIV: CD - Macromolecular Chemistry

  7. Development of durable and efficient electrodes for large-scale alkaline water electrolysis

    DEFF Research Database (Denmark)

    Kjartansdóttir, Cecilia Kristin; Nielsen, Lars Pleth; Møller, Per

    2013-01-01

    A new type of electrodes for alkaline water electrolysis is produced by physical vapour depositing (PVD) of aluminium onto a nickel substrate. The PVD Al/Ni is heat-treated to facilitate alloy formation followed by a selective aluminium alkaline leaching. The obtained porous Ni surface is uniform...... a commercially produced bipolar electrolyser stack. The developed electrodes showed stable behaviour under intermittent operation for over 9000 h indicating no serious deactivation in the density of active sites....

  8. Porous poly(perfluorosulfonic acid) membranes for alkaline water electrolysis

    DEFF Research Database (Denmark)

    Aili, David; Hansen, Martin Kalmar; Andreasen, Jens Wenzel;

    2015-01-01

    Poly(perfluorosulfonic acid) (PFSA) is one of a few polymer types that combine excellent alkali resistance with extreme hydrophilicity. It is therefore of interest as a base material in separators for alkaline water electrolyzers. In the pristine form it, however, shows high cation selectivity. To...... increase its ion conductivity in aqueous KOH, a method for the preparation of porous PFSA membranes was developed. It was based on an approach where PFSA was co-cast with poly(vinylpyrrolidone) (PVP) at different ratios to give transparent and colorless blend membranes. The PVP was subsequently dissolved...

  9. Alkaline water electrolysis technology for Space Station regenerative fuel cell energy storage

    Science.gov (United States)

    Schubert, F. H.; Hoberecht, M. A.; Le, M.

    1986-01-01

    The regenerative fuel cell system (RFCS), designed for application to the Space Station energy storage system, is based on state-of-the-art alkaline electrolyte technology and incorporates a dedicated fuel cell system (FCS) and water electrolysis subsystem (WES). In the present study, emphasis is placed on the WES portion of the RFCS. To ensure RFCS availability for the Space Station, the RFCS Space Station Prototype design was undertaken which included a 46-cell 0.93 cu m static feed water electrolysis module and three integrated mechanical components.

  10. Novel alkaline polymer electrolyte for water electrolysis with enhanced conductivity

    Czech Academy of Sciences Publication Activity Database

    Hnát, J.; Bouzek, B.; Paidar, M.; Schauer, Jan

    Praha : Process Engineering, 2010. s. 110-111. ISBN 978-80-02-02246-6. [International Congress of Chemical and Process Engineering CHISA 2010 /19./ and European Congress of Chemical Engineering ECCE-7 /7./. 28.08.2010-01.09.2010, Praha] Institutional research plan: CEZ:AV0Z40500505 Keywords : novel alkaline polymer * polyelectrolytes Subject RIV: CD - Macromolecular Chemistry

  11. Separating hydrogen and oxygen evolution in alkaline water electrolysis using nickel hydroxide.

    Science.gov (United States)

    Chen, Long; Dong, Xiaoli; Wang, Yonggang; Xia, Yongyao

    2016-01-01

    Low-cost alkaline water electrolysis has been considered a sustainable approach to producing hydrogen using renewable energy inputs, but preventing hydrogen/oxygen mixing and efficiently using the instable renewable energy are challenging. Here, using nickel hydroxide as a redox mediator, we decouple the hydrogen and oxygen production in alkaline water electrolysis, which overcomes the gas-mixing issue and may increase the use of renewable energy. In this architecture, the hydrogen production occurs at the cathode by water reduction, and the anodic Ni(OH)2 is simultaneously oxidized into NiOOH. The subsequent oxygen production involves a cathodic NiOOH reduction (NiOOH→Ni(OH)2) and an anodic OH(-) oxidization. Alternatively, the NiOOH formed during hydrogen production can be coupled with a zinc anode to form a NiOOH-Zn battery, and its discharge product (that is, Ni(OH)2) can be used to produce hydrogen again. This architecture brings a potential solution to facilitate renewables-to-hydrogen conversion. PMID:27199009

  12. Separating hydrogen and oxygen evolution in alkaline water electrolysis using nickel hydroxide

    Science.gov (United States)

    Chen, Long; Dong, Xiaoli; Wang, Yonggang; Xia, Yongyao

    2016-05-01

    Low-cost alkaline water electrolysis has been considered a sustainable approach to producing hydrogen using renewable energy inputs, but preventing hydrogen/oxygen mixing and efficiently using the instable renewable energy are challenging. Here, using nickel hydroxide as a redox mediator, we decouple the hydrogen and oxygen production in alkaline water electrolysis, which overcomes the gas-mixing issue and may increase the use of renewable energy. In this architecture, the hydrogen production occurs at the cathode by water reduction, and the anodic Ni(OH)2 is simultaneously oxidized into NiOOH. The subsequent oxygen production involves a cathodic NiOOH reduction (NiOOH-->Ni(OH)2) and an anodic OH- oxidization. Alternatively, the NiOOH formed during hydrogen production can be coupled with a zinc anode to form a NiOOH-Zn battery, and its discharge product (that is, Ni(OH)2) can be used to produce hydrogen again. This architecture brings a potential solution to facilitate renewables-to-hydrogen conversion.

  13. Separating hydrogen and oxygen evolution in alkaline water electrolysis using nickel hydroxide

    Science.gov (United States)

    Chen, Long; Dong, Xiaoli; Wang, Yonggang; Xia, Yongyao

    2016-01-01

    Low-cost alkaline water electrolysis has been considered a sustainable approach to producing hydrogen using renewable energy inputs, but preventing hydrogen/oxygen mixing and efficiently using the instable renewable energy are challenging. Here, using nickel hydroxide as a redox mediator, we decouple the hydrogen and oxygen production in alkaline water electrolysis, which overcomes the gas-mixing issue and may increase the use of renewable energy. In this architecture, the hydrogen production occurs at the cathode by water reduction, and the anodic Ni(OH)2 is simultaneously oxidized into NiOOH. The subsequent oxygen production involves a cathodic NiOOH reduction (NiOOH→Ni(OH)2) and an anodic OH− oxidization. Alternatively, the NiOOH formed during hydrogen production can be coupled with a zinc anode to form a NiOOH-Zn battery, and its discharge product (that is, Ni(OH)2) can be used to produce hydrogen again. This architecture brings a potential solution to facilitate renewables-to-hydrogen conversion. PMID:27199009

  14. Alkali doped poly (2,5-benzimidazole) membrane for alkaline water electrolysis: Characterization and performance

    Science.gov (United States)

    Diaz, Liliana A.; Hnát, Jaromír; Heredia, Nayra; Bruno, Mariano M.; Viva, Federico A.; Paidar, Martin; Corti, Horacio R.; Bouzek, Karel; Abuin, Graciela C.

    2016-04-01

    The properties and performance of linear and cross-linked KOH doped ABPBI membranes as electrolyte/separator for zero gap alkaline water electrolysis cells are evaluated and compared with a commercial Zirfon® diaphragm. Stability in alkaline environment, swelling, thermal properties, water sorption, KOH uptake and conductivity of linear (L-ABPBI) and cross-linked (C-ABPBI) membranes doped with different concentrations of KOH are analyzed. Linear membranes show stability up to 3.0 mol·dm-3 KOH doping, while cross-linked membranes are stable up to 4.2 mol·dm-3 KOH doping. Both kinds of membranes exhibit good thermal stability and reasonable specific ionic conductivity at 22 °C in the range between 7 and 25 mS·cm-1, being slightly higher the conductivity of C-ABPBI membranes than that of L-ABPBI ones. In short-term electrolysis tests both L-ABPBI and C-ABPBI membranes show better performance than Zirfon diaphragm in the range from 50 to 70 °C. A current density of 335 mA·cm-2 at a cell voltage of 2.0 V is attained with C-ABPBI membranes doped in 3 mol·dm-3 KOH at 70 °C, a performance comparable with that of commercial units operating at temperatures ca. 80 °C and 30 wt% KOH (6.7 mol·dm-3) as electrolyte.

  15. Heterogeneous anion conducting membranes based on linear and crosslinked KOH doped polybenzimidazole for alkaline water electrolysis

    DEFF Research Database (Denmark)

    Aili, David; Hansen, Martin Kalmar; Renzaho, Richard Fulgence;

    2013-01-01

    Polybenzimidazole is a highly hygroscopic polymer that can be doped with aqueous KOH to give a material with high ion conductivity in the 10−2Scm−1 range, which in combination with its low gas permeability makes it an interesting electrolyte material for alkaline water electrolysis. In this study...... membranes based on linear and crosslinked polybenzimidazole were evaluated for this purpose. Extensive characterization with respect to spectroscopic and physicochemical properties during aging in 6molL−1 KOH at 85°C for up to 176 days indicated structural stability of the high molecular weight specialty...... polymer, however, with limitations with respect to hydrolytic stability. The gradual decay of the average molecular weight resulted in a severe deterioration of the mechanical properties over time. Membranes based on crosslinked polybenzimidazole showed better stability than the membranes based on their...

  16. 2nd Generation Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Yde, Lars; Kjartansdóttir, Cecilia Kristin; Allebrod, Frank; Mogensen, Mogens Bjerg; Møller, Per; Hilbert, Lisbeth R.; Nielsen, Peter Tommy; Mathiesen, Troels; Jensen, Jørgen; Andersen, Lars; Dierking, Alexander

    This report provides the results of the 2nd Generation Alkaline Electrolysis project which was initiated in 2008. The project has been conducted from 2009-2012 by a consortium comprising Århus University Business and Social Science – Centre for Energy Technologies (CET (former HIRC)), Technical...

  17. Development and operation of a hybrid acid-alkaline advanced water electrolysis cell

    Science.gov (United States)

    Teschke, O.; Zwanziger, M.

    A hybrid acid-alkaline water electrolysis cell has been developed for hydrogen production. The cell is based on the use of an acidic solution at the cathode and a basic solution at the anode to reduce the minimum theoretical voltage for water decomposition from the thermoneutral potential of 1.47 V to close to 1.4 V at 25 C and 1 atm. The pH differential is maintained by the removal of OH ions from the cathode section and water removal from the anode section, which can be driven by heat energy. A practical cell has been built using a solid polymer electrolyte in which, however, the cathodic compartment is not acidic but neutral. Tests with a platinum black cathode catalyst and a platinum-iridium anode catalyst have resulted in steady-state water hydrolysis at an applied voltage of 0.9 V, and a V-I diagram with a considerably lower slope than that of a conventional cell has been obtained at 90 C.

  18. Synthesis and characterization of NiFe2O4 electrocatalyst for the hydrogen evolution reaction in alkaline water electrolysis using different polymer binders

    Czech Academy of Sciences Publication Activity Database

    Chanda, D.; Hnát, J.; Paidar, M.; Schauer, Jan; Bouzek, K.

    2015-01-01

    Roč. 285, 1 July (2015), s. 217-226. ISSN 0378-7753 Institutional support: RVO:61389013 Keywords : alkaline water electrolysis * spinel oxides * polymer binder Subject RIV: CG - Electrochemistry Impact factor: 6.217, year: 2014

  19. High Temperature and Pressure Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank

    radiation raises the necessity to store the produced energy. Hydrogen production by water electrolysis is one of the most promising ways to do so. Alkaline electrolyzers have proven to operate reliable for decades on a large scale (up to 160 MW), but in order to become commercially attractive and compete...... and oxygen with a new type of alkaline electrolysis cell at high temperatures and pressures. To perform measurements under high pressure and at elevated temperatures it was necessary to build a measurement system around an autoclave which could stand high temperatures up to 250 °C and pressures up to...... 200 bar as well as extremely caustic environments. Based on a literature study to identify resistant materials for these conditions, Inconel 600 was selected among the metals which are available for autoclave construction. An initial single atmosphere high temperature and pressure measurement setup...

  20. Oxygen evolution reaction characteristics of synthetic nickel-cobalt-oxide electrodes for alkaline anion-exchange membrane water electrolysis

    Science.gov (United States)

    Koo, Tae Woo; Park, ChanSu; Kim, Yang Do; Lee, Dooyong; Park, Sungkyun; Lee, Jae Ho; Choi, Sung Mook; Choi, Chul Young

    2015-11-01

    A polymer electrolyte membrane water electrolysis system can produce high-purity hydrogen gases in a highly efficient manner. However, the level of hydrogen gas production is still small. In addition, noble-metal catalysts for the reaction in acidic environments, as well as an additional drying step to remove water contained in the hydrogen, are required. Therefore, water electrolysis system with high efficiency and lower cost, an alkaline anion-exchange membrane system that can produce high-purity hydrogen without a noble-metal catalyst, is needed. Nano-size NiCo2O4 powders were prepared by using a sol-gel method to achieve an efficient and economical water electrolysis system. When the powder was calcined at 450 °C, the crystallinity and the cyclic voltammogram measurement showed the best values. In addition, the 15-wt.% polytetrafluoroethylene mixed NiCo2O4 powders exhibited the largest cyclic voltammetry active area and the highest oxygen evolution reaction activity with the appropriate stability.

  1. Manufacturing of a LaNiO3 composite electrode for oxygen evolution in commercial alkaline water electrolysis

    DEFF Research Database (Denmark)

    Egelund, Sune; Caspersen, Michael; Nikiforov, Aleksey Valerievich;

    2016-01-01

    results were compared to a non-catalysed Watts nickel reference sample and the electrochemical measurements confirmed that the coating decreased the OER overpotential by 70 mV. XRD furthermore revealed that a LaNiO3 + Ni composite structure was obtained. Conventional alkaline water electrolysis...... was carried out at a temperature of 120 °C and a current densities of 0.2 and 0.8 A cm-2. Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD) were used for characterization of the morphology....

  2. Polymer anion-selective membranes for electrolytic splitting of water. Part II: enhancement of ionic conductivity and performance under conditions of alkaline water electrolysis

    Czech Academy of Sciences Publication Activity Database

    Hnát, J.; Paidar, M.; Schauer, Jan; Žitka, Jan; Bouzek, K.

    2012-01-01

    Roč. 42, č. 8 (2012), s. 545-554. ISSN 0021-891X R&D Projects: GA MŠk(CZ) 7E08005 EU Projects: European Commission(XE) 212903 - WELTEMP Institutional research plan: CEZ:AV0Z40500505 Keywords : water electrolysis * alkaline environment * polymer electrolyte Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.836, year: 2012

  3. Alkaline Electrolysis Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    RIchard Bourgeois; Steven Sanborn; Eliot Assimakopoulos

    2006-07-13

    In this project, GE developed electrolyzer stack technologies to meet DOE’s goals for low cost electrolysis hydrogen. The main barrier to meeting the targets for electrolyzer cost was in stack assembly and construction. GE’s invention of a single piece or “monolithic” plastic electrolyzer stack reduces these costs considerably. In addition, GE developed low cost cell electrodes using a novel application of metal spray coating technology. Bench scale stack testing and cost modeling indicates that the DOE targets for stack capital cost and efficiency can be met by full-scale production of industrial electrolyzers incorporating GE’s stack technology innovations.

  4. High temperature and pressure alkaline electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2013-01-01

    Alkaline electrolyzers have proven to operate reliable for decades on a large scale, but in order to become commercially attractive and compete against conventional technologies for hydrogen production, the production and investment costs have to be reduced. This may occur by increasing the...... operational temperature and pressure to produce pressurized hydrogen at high rate (m3 H2·h-1·m-2 cell area) and high electrical efficiency. This work describes an exploratory technical study of the possibility to produce hydrogen and oxygen with a new type of alkaline electrolysis cell at high temperatures...... SrTiO3 was used for immobilization of aqueous KOH solutions. Electrolysis cells with this electrolyte and metal foam based gas diffusion electrodes were successfully demonstrated at temperatures up to 250 °C at 40 bar. Different electro-catalysts were tested in order to reduce the oxygen and hydrogen...

  5. Electrochemical Deposition and Characterization of Ni-Mo Alloys as Cathode for Alkaline Water Electrolysis

    Science.gov (United States)

    Manazoğlu, Mert; Hapçı, Gökçe; Orhan, Gökhan

    2016-01-01

    In this study, Ni-Mo alloy coatings were electrochemically deposited on a copper plate in citrate solutions. The effects of Ni/Mo mole ratio in the electrolyte and pH value on hydrogen evolution reaction (HER) as well as the electrochemical stability were investigated in the alkaline solution for electrodeposited NiMo. The electrocatalytic activity of the fabricated NiMo alloys for HER in alkaline solutions was investigated by the polarization measurements and electrochemical impedance spectroscopy techniques. The morphology and chemical composition of the electrodeposited Ni-Mo were investigated using SEM and EDS analyses. It was found that NiMo electrode with the highest molybdenum content (ca. 38 wt.%) and high surface area show high electrocatalytic activity in the HER. This was produced from a bath with a pH of 9.5, Ni/Mo ratio of 1/10 and 0.5 M sodium citrate concentration. The stability of this coating was tested by polarization measurements after different anodic and cathodic treatment in 1 M NaOH solution. The open circuit potential ( E ocp) of the electrode as a function of immersion time was also measured.

  6. Raising efficiency of hydrogen generation from alkaline water electrolysis - Energy saving

    Energy Technology Data Exchange (ETDEWEB)

    Nikolic, Vladimir M.; Tasic, Gvozden S.; Maksic, Aleksandar D.; Saponjic, Djordje P.; Marceta Kaninski, Milica P. [Vinca Institute of Nuclear Sciences, Department of Physical Chemistry, 11001 Belgrade, POB 522 (RS); Miulovic, Snezana M. [University of Belgrade, Faculty of Physical Chemistry, 11001 Belgrade, POB 276 (RS)

    2010-11-15

    This paper presents an attempt to make the alkaline electrolytic production of hydrogen more efficient by adding in situ activating compounds in ionic and complex form. Cobalt and tungsten based ionic activators (i.a.), added directly into the electrolyte during the electrolytic process, reduce energy requirements per mass unit of hydrogen produced for about 15%, compared to non-activated system, for a number of current densities in a wide temperature range. Energy saving is higher at higher temperatures and on higher current densities. Structural and morphological characteristic of deposit formed on the cathode during the electrolytic process reveal very interesting and unique pattern with highly developed surface area and uniform distribution of the pores. Obtained deposit also exhibit a long term stability. (author)

  7. Effect of Morphology of Co3O4 for Oxygen Evolution Reaction in Alkaline Water Electrolysis

    OpenAIRE

    Xu, Qi-Zhi; Su, Yu-Zhi; Wu, Hao; Cheng, Hui; Hui, Yun-Ping; Li, Nan; Liu, Zhao-Qing

    2014-01-01

    In this paper, three different morphological Co3O4 electrodes for oxygen evolution reaction (OER) have been synthesized. By comparing the three morphologies of Co3O4, the electrocatalytic properties show that the urchin-like spheres of Co3O4 electrode has relative low overpotential and good electrocatalysis stability, indicating that the structure of urchin-like Co3O4 spheres exhibit an easy OER for water splitting.

  8. Synthesis and characterization of NiFe2O4 electrocatalyst for the hydrogen evolution reaction in alkaline water electrolysis using different polymer binders

    Science.gov (United States)

    Chanda, Debabrata; Hnát, Jaromír; Paidar, Martin; Schauer, Jan; Bouzek, Karel

    2015-07-01

    NiFe2O4 electrocatalyst for the hydrogen evolution reaction (HER) has been synthesized using the co-precipitation method of the respective metal ions from water solution. After calcination of the precipitate, the resulting electrocatalyst was characterized by a broad range of techniques to obtain information on its crystallographic structure, specific surface area, morphology and chemical composition. The electrocatalytic activity towards HER in alkaline water electrolysis was investigated by means of linear sweep voltammetry. The catalyst showed promising electrocatalytic properties. Subsequently three types of binders were used to prepare a cathode catalytic layer based on a catalyst synthesized on top of a nickel foam support, namely an anion-selective quaternized poly(phenylene oxide) (qPPO) ionomer, an electroneutral polymer polytetrafluoroethylene and cation-selective Nafion®. The resulting membrane-electrode assemblies (MEAs), based on an anion-selective membrane, were tested in an alkaline water electrolyzer. In a single-cell test the MEA with a qPPO ionomer exhibited higher HER activity compared to the remaining binders tested. The current density obtained using a MEA containing qPPO binder attained a value of 125 mA cm-2 at a cell voltage of 1.85 V. The stability of the MEA containing qPPO binder was examined by continuous operation for 143 h, followed by 55 h intermittent electrolysis.

  9. 2nd Generation alkaline electrolysis. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Yde, L. [Aarhus Univ. Business and Social Science - Centre for Energy Technologies (CET), Aarhus (Denmark); Kjartansdottir, C.K. [Technical Univ. of Denmark. DTU Mechanical Engineering, Kgs. Lyngby (Denmark); Allebrod, F. [Technical Univ. of Denmark. DTU Energy Conversion, DTU Risoe Campus, Roskilde (Denmark)] [and others

    2013-03-15

    conditions and the degradation mechanism was examined. One of the strong visions for the 2{sup nd} generation electrolyser concept has been to develop a modular system with several standardized components. The following modules have been designed: 1) Electrolyser module; 2) Deoxer Module; 3) Dryer Module; 4) Water Treatment Module; 5) Power supply and Control unit; 6) Rack mount. The developed 2{sup nd} generation rack-mounted alkaline electrolyser system has been installed and demonstrated for 18 month in a college (H2College) with 66 apartments. A number of measurements were performed on the system installed in H2College. No measurements on the overall system efficiency were conducted. However measurement on the stack showed a stack efficiency of 86.5% at a current density of 177mA/cm{sup 2} and a temperature of 74.4 deg. C at the hydrogen outlet. The system is estimated to have run roughly 2000h during the demonstration period. The demonstration of the 2{sup nd} generation alkaline electrolyser is considered a success for several reasons. While not all technical goals were reached, the research and development in the project have resulted in some very good solutions for most of the challenges in high pressure alkaline electrolysis. The concept of a rack mounted electrolyser was proven viable, and all critical aspects of the modularisation have been covered. (LN)

  10. Foam Based Gas Diffusion Electrodes for Reversible Alkaline Electrolysis Cells

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    Alkaline electrolysis cells operated at 250 °C and 40 bar have shown to be able to convert electrical energy into hydrogen at very high efficiencies and power densities. Foam based gas diffusion electrodes and an immobilized electrolyte allow for reversible operation as electrolysis cell or fuel...

  11. Comprehensive Study of an Earth-Abundant Bifunctional 3D Electrode for Efficient Water Electrolysis in Alkaline Medium.

    Science.gov (United States)

    Sharifi, Tiva; Gracia-Espino, Eduardo; Jia, Xueen; Sandström, Robin; Wågberg, Thomas

    2015-12-30

    We report efficient electrolysis of both water-splitting half reactions in the same medium by a bifunctional 3D electrode comprising Co3O4 nanospheres nucleated on the surface of nitrogen-doped carbon nanotubes (NCNTs) that in turn are grown on conductive carbon paper (CP). The resulting electrode exhibits high stability and large electrochemical activity for both oxygen and hydrogen evolution reactions (OER and HER). We obtain a current density of 10 mA/cm(2) in 0.1 M KOH solution at overpotentials of only 0.47 and 0.38 V for OER and HER, respectively. Additionally, the experimental observations are understood and supported by analyzing the Co3O4:NCNT and NCNT:CP interfaces by ab initio calculations. Both the experimental and the theoretical studies indicate that firm and well-established interfaces along the electrode play a crucial role on the stability and electrochemical activity for both OER and HER. PMID:26629887

  12. 碱性电解水析氢电极的研究进展%Research progress in hydrogen electrode materials for alkaline water electrolysis

    Institute of Scientific and Technical Information of China (English)

    张开悦; 刘伟华; 陈晖; 张博; 刘建国; 严川伟

    2015-01-01

    电解水制氢将成为未来绿色制氢工业的核心技术。研究新型阴极材料以有效降低阴极过电位,对降低电解水能耗和设备成本、提高生产稳定性和安全性,具有十分重要的现实意义。本文主要对碱性水溶液电解制氢工业的析氢阴极材料进行综述。围绕电极结晶结构设计和尺寸结构设计两个主要的电极发展方向,重点介绍了3类基于电沉积制备技术的Ni基电极材料:合金析氢电极、复合析氢电极、多孔析氢电极。分析了当前析氢电极在实验研发与工业应用中存在的问题。指出采用电沉积法,制备催化活性更高且适用于工业电解环境的多元复合电极材料将是今后析氢电极发展的趋势。%Water electrolysis will become the core technology of environmental production for hydrogen industry in the future. It is very important to study new cathode materials for reducing the cathode overpotential. Because it not only can reduce energy consumption and the cost of water electrolysis,but also can enhance the stability and safety of production. This paper mainly discusses the research status of hydrogen electrode materials for alkaline water electrolysis. Based on the major improvement of catalytic activity for hydrogen evolution reaction,this paper mainly focuses on the electrodepositing preparation method for three kinds of nickel-based electrodes,which are alloy hydrogen evolution electrode,composite hydrogen evolution electrode,and porous hydrogen evolution electrode. The existing problems on hydrogen evolution electrode in experimental research and industrial application are analyzed. In the end,it is pointed out that the more catalytic activity and more stable electrochemical performance of multivariate composite electrodes based on electrodepositing preparation will be the future of hydrogen electrode development.

  13. Electrochemical investigation of surface area effects on PVD Al-Ni as electrocatalyst for alkaline water electrolysis

    DEFF Research Database (Denmark)

    Kjartansdóttir, Cecilía Kristín; Caspersen, Michael; Egelund, Sune Daaskov; Møller, Per

    2014-01-01

    A thermo-chemical diffusion of vapour deposited aluminium onto a nickel substrate, leads to a rapid formation of an Al/Ni intermetallic layer that is particularly acceptable for dissolution of aluminium in strong alkali. The geometry and the structure of the final skeletal nickel coatings can be ...... to above 2000, additional 40mV are gained. For the OER, smaller roughness values were observed with the same activity trend as for the HER. The electrocatalyst are however found not to be stable in the anodic environment during electrolysis. The corrosion mechanism of a skeletal nickel...

  14. Electrochemical investigation of surface area effects on PVD Al-Ni as electrocatalyst for alkaline water electrolysis

    DEFF Research Database (Denmark)

    Kjartansdóttir, Cecilía Kristín; Caspersen, Michael; Egelund, Sune Daaskov;

    2014-01-01

    A thermo-chemical diffusion of vapour deposited aluminium onto a nickel substrate, leads to a rapid formation of an Al/Ni intermetallic layer that is particularly acceptable for dissolution of aluminium in strong alkali. The geometry and the structure of the final skeletal nickel coatings can be...... to above 2000, additional 40mV are gained. For the OER, smaller roughness values were observed with the same activity trend as for the HER. The electrocatalyst are however found not to be stable in the anodic environment during electrolysis. The corrosion mechanism of a skeletal nickel...

  15. An efficient route for catalytic activity promotion via hybrid electro-depositional modification on commercial nickel foam for hydrogen evolution reaction in alkaline water electrolysis

    International Nuclear Information System (INIS)

    Highlights: • Mono-Cu surface modification depress the HER activity of Ni-foam. • Hybrid Ni-foam/Cu0.01/Co0.05 exhibits superior HER performance. • Layer-by-layer structure may contribute to a synergistic promoting effect. - Abstract: In this paper, the single- and hybrid-layered Cu, Ni and Co thin films were electrochemically deposited onto the three-dimensional nickel foam as composite cathode catalyst for hydrogen evolution reaction in alkaline water electrolysis. The morphology, structure and chemical composition of the electrodeposited composite catalysts were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Electrochemical measurement depicted that, for the case of the monometallic layered samples, the general activity for hydrogen evolution reaction followed the sequence: Ni-foam/Ni > Ni-foam/Co > bare Ni-foam > Ni-foam/Cu. It is noteworthy that, the hybrid-layered Ni-foam/Cu0.01/Co0.05 exhibited the highest catalytic activity towards hydrogen evolution reaction with the current density as high as 2.82 times that of the bare Ni-foam. Moreover, both excellent electrochemical and physical stabilities can also be acquired on the Ni-foam/Cu0.01/Co0.05, making this hybrid-layered composite structure as a promising HER electro-catalyst

  16. Foam Based Gas Diffusion Electrodes for Reversible Alkaline Electrolysis Cells

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    Alkaline electrolysis cells operated at 250 °C and 40 bar have shown to be able to convert electrical energy into hydrogen at very high efficiencies and power densities. Foam based gas diffusion electrodes and an immobilized electrolyte allow for reversible operation as electrolysis cell or fuel...... cell. In the present work we demonstrate the application of hydrophobic, porous, and electro-catalytically active gas diffusion electrodes. PTFE particles and silver nanowires as electro-catalysts were used in the gas diffusion electrodes. Impedance spectroscopy and cyclic voltammetry were performed to...

  17. Foam Based Gas Diffusion Electrodes for Reversible Alkaline Electrolysis Cells

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    Alkaline electrolysis cells operated at 250 °C and 40 bar have shown to be able to convert electrical energy into chemical energy in the form of hydrogen at very high efficiencies and power densities. Foam based gas diffusion electrodes and a liquid immobilized electrolyte allow the operation of...... the newly designed electrolysis cell as a fuel cell, but condensation of steam may lead to blocked pores, thereby inhibiting gas diffusion and decreasing the performance of the cell. In the here presented work we present the application of a hydrophobic, porous, and electro-catalytically active layer...

  18. High temperature and pressure alkaline electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2013-01-01

    SrTiO3 was used for immobilization of aqueous KOH solutions. Electrolysis cells with this electrolyte and metal foam based gas diffusion electrodes were successfully demonstrated at temperatures up to 250 °C at 40 bar. Different electro-catalysts were tested in order to reduce the oxygen and hydrogen...... overpotentials. Current densities of 1.1 A cm-2 and 2.3 A cm-2 have been measured at a cell voltage of 1.5 V and 1.75 V, respectively, without noble metal catalysts. Electrical efficiencies of almost 99 % at 1.1 A cm-2 and 85 % at 2.3 A cm-2 were obtained....

  19. PEM Water Electrolysis at Elevated Temperatures

    DEFF Research Database (Denmark)

    Hansen, Martin Kalmar

    needed and hence it has become acute to be able to store the energy. Hydrogen has been identified as a suitable energy carrier and water electrolysis is one way to produce it in a sustainable and environmentally friendly way. In this thesis an introduction to the subject (chapter 1) is given followed by...... a literature review of the field of water electrolysis (chapter 2), with a focus on proton exchange membrane (PEM) electrolysis. In chapter 3 a short description of the experimental techniques used for synthesis of catalyst and characterisation of the components in the electrolysis cell is given....... This is followed in chapter 4 by a description of the electrolysis setups and electrolysis cells used during the work. Two different setups were used, one operating at atmospheric pressure and another that could operate at elevated pressure so that liquid water electrolysis could be performed at...

  20. Desulfurization from Bauxite Water Slurry (BWS) Electrolysis

    Science.gov (United States)

    Gong, Xuzhong; Ge, Lan; Wang, Zhi; Zhuang, Siyuan; Wang, Yuhua; Ren, Lihui; Wang, Mingyong

    2016-02-01

    Feasibility of high-sulfur bauxite electrolysis desulfurization was examined using the electrochemical characterization, XRD, DTA, and FTIR. The cyclic voltammetry curves indicated that bauxite water slurry (BWS) electrolysis in NaOH system was controlled by diffusion. Additionally, the desulfurization effect of NaCl as the electrolyte was significantly better than that of NaOH as an electrolyte. As the stirring rate increased, the desulfurization ratio in NaCl system was not increased obviously, while the desulfurization ratio in NaOH system increased significantly, indicating further that electrolysis desulfurization in NaOH solution was controlled by diffusion. According to XRD, DTA, and FTIR analysis, the characteristic peaks of sulfur-containing phase in bauxite after electrolysis weakened or disappeared, indicating that the pyrite in bauxite was removed from electrolysis. Finally, the electrolytic desulfurization technology of bauxite was proposed based on the characteristics of BWS electrolysis.

  1. Alkaline Ammonia Electrolysis on Electrodeposited Platinum for Controllable Hydrogen Production.

    Science.gov (United States)

    Gwak, Jieun; Choun, Myounghoon; Lee, Jaeyoung

    2016-02-19

    Ammonia is beginning to attract a great deal of attention as an alternative energy source carrier, because clean hydrogen can be produced through electrolytic processes without the emission of COx . In this study, we deposited various shapes of Pt catalysts under potentiostatic mode; the electrocatalytic oxidation behavior of ammonia using these catalysts was studied in alkaline media. The electrodeposited Pt was characterized by both qualitative and quantitative analysis. To discover the optimal structure and the effect of ammonia concentration, the bulk pH value, reaction temperature, and applied current of ammonia oxidation were investigated using potential sweep and galvanostatic methods. Finally, ammonia electrolysis was conducted using a zero-gap cell, producing highly pure hydrogen with an energy efficiency over 80 %. PMID:26530809

  2. Alkaline and high-temperature electrolysis for nuclear hydrogen production

    International Nuclear Information System (INIS)

    In anticipation to energy world evolution in the coming decades, we will discuss the role that hydrogen can play in the future energy systems. Facing strong energy demand growth in the transport field, expected oil production limitation and climate change constraints, the oil industry has to raise difficult challenges requiring short-term actions. Hydrogen being a key molecule for this industry, we will show how nuclear produced hydrogen can contribute to resolve some of the oil industry challenges, within a compatible time frame with the inertia of climate mechanisms. Technical solutions to produce hydrogen using nuclear energy and electrolysis will then be described. We will describe the relevant characteristics of alkaline electrolyser technology. Using results of nuclear-aided petrochemical processes technico-economic studies, we will show that synthetic fuels are accessible at reasonable costs. We will also discuss the limitations of these technological solutions and describe which improvements and evolutions can be expected and looked for, as regards both the nuclear industry and electrolyser technologies. For the latter, we will discuss both alkaline and high-temperature electrolysis. The evolutions to be looked for should minimise development efforts, therefore we will argue why advanced thermal integration should be studied in order to avoid too-stringent requirements on both the nuclear reactor and the electrolyser. Remaining challenges will be discussed. As a result, our paper will show how and why the nuclear industry, and specifically AREVA, will be able with relatively limited developments to massively de-carbonise transportation from well to wheel, through a variety of applications. (authors)

  3. Solid polymer electrolyte water electrolysis

    Science.gov (United States)

    Takenaka, H.; Torikai, E.; Kawami, Y.; Wakabayashi, N.

    Electrocatalyst performances and bonding to solid polymer electrolytes used for water electrolysis are investigated. Noble metal and metal alloy catalysts were plated to Nafion perfluorosulfonic acid polymer membranes without a binder by the use of a reducing agent solution held on the opposite side of the membrane from a metal salt solution. It was found that pretreatment of the membrane by hydrothermal treatment or gas plasma surface roughening improves metal adhesivity and thus reduces contact resistance between the membrane and the catalyst. Measurements of the constituents of cell voltage for platinum, rhodium and iridium anodes with platinum cathodes reveals that anodic overvoltage is a major component of voltage loss and depends on the type of electrocatalyst, being greatest for Pd and least for Ir. Ir and Ir-alloy electrodes, which were found to be the best catalysts for oxygen evolution, are found to have Tafel slopes of 0.04-0.06 V/decade. In a cell with a Pt cathode and Ir anode, cell voltage is observed to decrease with increasing temperature, reaching 1.56-1.59 V at a current density of 50 A/sq dm and 90 C, which corresponds to a thermal efficiency of 93-95%.

  4. Electrolysis

    DEFF Research Database (Denmark)

    Smith, Anders; Pedersen, Allan Schrøder

    2014-01-01

    Electrolysis is a well-established technology with many different applications. In particular, it can be used to produce hydrogen by using electricity to split water. As an increasing part of the energy system consists of fluctuating power sources such as wind and solar it becomes increasingly...

  5. Base-acid hybrid water electrolysis.

    Science.gov (United States)

    Chen, Long; Dong, Xiaoli; Wang, Fei; Wang, Yonggang; Xia, Yongyao

    2016-02-21

    A base-acid hybrid electrolytic system with a low onset voltage of 0.78 V for water electrolysis was developed by using a ceramic Li-ion exchange membrane to separate the oxygen-evolving reaction (OER) in a basic electrolyte solution containing the Li-ion and hydrogen-evolving reaction (HER) in an acidic electrolyte solution. PMID:26804323

  6. High-pressure water electrolysis: Electrochemical mitigation of product gas crossover

    International Nuclear Information System (INIS)

    Highlights: • New technique to reduce gas crossover during water electrolysis • Increase of the efficiency of pressurized water electrolysis • Prevention of safety hazards due to explosive gas mixtures caused by crossover • Experimental realization for a polymer electrolyte membrane electrolyzer • Discussion of electrochemical crossover mitigation for alkaline water electrolysis - Abstract: Hydrogen produced by water electrolysis can be used as an energy carrier storing electricity generated from renewables. During water electrolysis hydrogen can be evolved under pressure at isothermal conditions, enabling highly efficient compression. However, the permeation of hydrogen through the electrolyte increases with operating pressure and leads to efficiency loss and safety hazards. In this study, we report on an innovative concept, where the hydrogen crossover is electrochemically mitigated by an additional electrode between the anode and the cathode of the electrolysis cell. Experimentally, the technique was applied to a proton exchange membrane water electrolyzer operated at a hydrogen pressure that was fifty times larger than the oxygen pressure. Therewith, the hydrogen crossover was reduced and the current efficiency during partial load operation was increased. The concept is also discussed for water electrolysis that is operated at balanced pressures, where the crossover of hydrogen and oxygen is mitigated using two additional electrodes

  7. Highly efficient platinum group metal free based membrane-electrode assembly for anion exchange membrane water electrolysis.

    Science.gov (United States)

    Pavel, Claudiu C; Cecconi, Franco; Emiliani, Chiara; Santiccioli, Serena; Scaffidi, Adriana; Catanorchi, Stefano; Comotti, Massimiliano

    2014-01-27

    Low-temperature electricity-driven water splitting is an established technology for hydrogen production. However, the two main types, namely proton exchange membrane (PEM) and liquid alkaline electrolysis, have limitations. For instance, PEM electrolysis requires a high amount of costly platinum-group-metal (PGM) catalysts, and liquid alkaline electrolysis is not well suited for intermittent operation. Herein we report a highly efficient alkaline polymer electrolysis design, which uses a membrane-electrode assembly (MEA) based on low-cost transition-metal catalysts and an anion exchange membrane (AEM). This system exhibited similar performance to the one achievable with PGM catalysts. Moreover, it is very suitable for intermittent power operation, durable, and able to efficiently operate at differential pressure up to 3 MPa. This system combines the benefits of PEM and liquid alkaline technologies allowing the scalable production of low-cost hydrogen from renewable sources. PMID:24339230

  8. Electrocatalysts for medium temperature PEM water electrolysis

    OpenAIRE

    Zlotorowicz, Agnieszka

    2013-01-01

    The main subject of this PhD thesis is the fabrication and investigation the electrochemical behavior of anode catalysts appropriate for medium- temperature proton exchange membrane (PEM) water electrolysis (WE) operating in the range 100 oC through 200 oC. These catalysts were based on metal oxides, primarily IrO2 and its mixtures with some other oxides, and investigated as oxygen evolution electrocatalysts. A central research challenge in this project has been to understand the interaction ...

  9. Modeling surface nanobubbles in water electrolysis

    OpenAIRE

    Sperre, Asbjørn Hopland

    2015-01-01

    In this project a steady state approach is used to study the stability of surface nanobubbles in water electrolysis. A two dimensional domain is considered, where an electrode of length 100 nm is partly covered by a bubble. The results indicates that a single nanobubble which partially covers the electrode can be stable, as long as the electrogeneration of hydrogen is suffcient to balance the dissolution of hydrogen at near the cap of the bubble. The effect of the evaporation r...

  10. Increased performance of hydrogen production in microbial electrolysis cells under alkaline conditions.

    Science.gov (United States)

    Rago, Laura; Baeza, Juan A; Guisasola, Albert

    2016-06-01

    This work reports the first successful enrichment and operation of alkaline bioelectrochemical systems (microbial fuel cells, MFC, and microbial electrolysis cells, MEC). Alkaline (pH=9.3) bioelectrochemical hydrogen production presented better performance (+117%) compared to conventional neutral conditions (2.6 vs 1.2litres of hydrogen gas per litre of reactor per day, LH2·L(-1)REACTOR·d(-1)). Pyrosequencing results of the anodic biofilm showed that while Geobacter was mainly detected under conventional neutral conditions, Geoalkalibacter sp. was highly detected in the alkaline MFC (21%) and MEC (48%). This is the first report of a high enrichment of Geoalkalibacter from an anaerobic mixed culture using alkaline conditions in an MEC. Moreover, Alkalibacter sp. was highly present in the anodic biofilm of the alkaline MFC (37%), which would indicate its potentiality as a new exoelectrogen. PMID:26855359

  11. Vehicle Integrated Photovoltaics for Compression Ignition Vehicles: An Experimental Investigation of Solar Alkaline Water Electrolysis for Improving Diesel Combustion and a Solar Charging System for Reducing Auxiliary Engine Loads

    Science.gov (United States)

    Negroni, Garry Inocentes

    Vehicle-integrated photovoltaic electricity can be applied towards aspiration of hydrogen-oxygen-steam gas produced through alkaline electrolysis and reductions in auxiliary alternator load for reducing hydrocarbon emissions in low nitrogen oxide indirect-injection compression-ignition engines. Aspiration of 0.516 ± 0.007 liters-per-minute of gas produced through alkaline electrolysis of potassium-hydroxide 2wt.% improves full-load performance; however, part-load performance decreases due to auto-ignition of aspirated gas prior to top-dead center. Alternator load reductions offer improved part-load and full-load performance with practical limitations resulting from accessory electrical loads. In an additive approach, solar electrolysis can electrochemically convert solar photovoltaic electricity into a gas comprised of stoichiometric hydrogen and oxygen gas. Aspiration of this hydrogen-oxygen gas enhances combustion properties decreasing emissions and increased combustion efficiency in light-duty diesel vehicles. The 316L stainless steel (SS) electrolyser plates are arranged with two anodes and three cathodes space with four bipolar plates delineating four stacks in parallel with five cells per stack. The electrolyser was tested using potassium hydroxide 2 wt.% and hydronium 3wt.% at measured voltage and current inputs. The flow rate output from the reservoir cell was measured in parallel with the V and I inputs producing a regression model correlating current input to flow rate. KOH 2 wt.% produced 0.005 LPM/W, while H9O44 3 wt.% produced less at 0.00126 LPM/W. In a subtractive approach, solar energy can be used to charge a larger energy storage device, as is with plug-in electric vehicles, in order to alleviate the engine of the mechanical load placed upon it by the vehicles electrical accessories through the alternator. Solar electrolysis can improve part-load emissions and full-load performance. The average solar-to-battery efficiency based on the OEM rated

  12. Perovskites As Electrocatalysts for Alkaline Water Electrolysis

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey Valerievich; De La Osa Puebla, Ana Raquel; Jensen, Jens Oluf;

    2014-01-01

    robust method for synthesis of perovskites with various chemical compositions1. The electrochemical performance of the materials was tested through pellet pressing of the perovskite powders. This involved in some case a time consuming preparation process. Furthermore the technique should show the...... adequate reproducibility.2 In this work we show the development of the method, which was further used to compare the activity of various electrocatalysts (Figures 1,2). The electrocatalytic activity of all prepared perovskites was tested in 1M KOH at 80 °C, using an ink consisting of potassium exchanged...... Nafion®. All tests were performed in the potential window 0-700 mV on a glassy carbon electrode. All the tested perovskites were characterized by their overpotential , measured current at 650 mV, obtained kinetic current and Tafel slopes. It was also shown that this technique do not depend on the initial...

  13. High Temperature Alkaline Electrolysis Cells with Metal Foam Based Gas Diffusion Electrodes

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos; Allebrod, Frank; Mogensen, Mogens Bjerg

    2016-01-01

    Alkaline electrolysis cells operating at 250°C and 40 bar are able to convert electrical energy into hydrogen at very high efficiencies and power densities. In the present work we demonstrate the application of a PTFE hydrophobic network and Ag nanowires as oxygen evolution electrocatalyst in the...... metal foam based gas diffusion electrodes. A novel cell production method, based on tape casting and hot pressing, was developed which allows to increase the cell size from lab scale (1 cm2) to areas of 25 cm2 or larger. The thickness of the electrolyte matrix could be adjusted to only 200 μm, achieving...... novel cell concept promises more than a 10-fold improvement in power density, compared to conventional alkaline electrolysis cells, and thereby equivalent reduction in stack size and cost....

  14. Improved electrodes and gas impurity investigations on alkaline electrolysers

    DEFF Research Database (Denmark)

    Reissner, R.; Schiller, G.; Knoeri, T.;

    Alkaline water electrolysis for hydrogenproduction is a well-established techniquebut some technological issues regarding thecoupling of alkaline water electrolysis andRenewable Energy Sources (RES) remain tobe improved....

  15. Water electrolysis in the presence of an ultrasonic field

    International Nuclear Information System (INIS)

    The energy efficiency of water electrolysis has been considerably improved in the presence of an ultrasonic field. This was demonstrated by measuring the cell voltage, efficiency and energy consumption of the generated gas from the electrolysis. These measurements were carried out in alkaline solution using linear sweep voltammetry (LSV) and galvanostatic polarization techniques. A large reduction of the cell voltage was achieved under the ultrasonic field, especially at high current density and low electrolyte concentration. With the same current density, the cell voltage difference with and without the ultrasonic field fell as the concentration of the electrolyte was increased. The efficiency of H2 generation was improved at a range of 5-18% at high current density in the ultrasonic field but the efficiency of O2 generation fell a little due to the difference in the behavior of the gas bubbles. The energy saving for H2 production by using the ultrasonic field was about 10-25% for a certain concentration of the electrolyte when a high current density was used. On the other hand, the energy consumption for O2 production with and without the ultrasonic field was almost the same.

  16. Preparation, characterization and application of alkaline leached CuNiZn ternary coatings for long-term electrolysis in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Solmaz, Ramazan [Bingoel University, Science and Letters Faculty, Chemistry Department, 12000 Bingoel (Turkey); Doener, Ali; Kardas, Guelfeza [Cukurova University, Science and Letters Faculty, Chemistry Department, 01330 Balcali Adana (Turkey)

    2010-10-15

    The NiCuZn ternary coating was electrochemically deposited on a copper electrode. Then, it was etched in a concentrated alkaline solution (30% NaOH) to produce a porous and electrocatalytic surface suitable for use in the hydrogen evolution reaction (HER). The surface composition of coating before and after alkaline leaching was determined by energy dispersive X-ray (EDX) analysis. The surface morphologies were investigated by scanning electron microscopy (SEM). The long-term stability of electrode prepared for alkaline water electrolysis was investigated in 1 M KOH solution with the help of cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. It was found that, the NiCuZn coating has a compact and porous structure with good physical stability. Alkaline leaching process further improved the activity of NiCuZn coating in comparison with binary NiCu deposit for the HER. The long-term operation at -100 mA cm{sup -2} showed good electrochemical stability over 120 h. (author)

  17. Water electrolysis on La1-xSrxCoO3-δ perovskite electrocatalysts

    Science.gov (United States)

    Mefford, J. Tyler; Rong, Xi; Abakumov, Artem M.; Hardin, William G.; Dai, Sheng; Kolpak, Alexie M.; Johnston, Keith P.; Stevenson, Keith J.

    2016-03-01

    Perovskite oxides are attractive candidates as catalysts for the electrolysis of water in alkaline energy storage and conversion systems. However, the rational design of active catalysts has been hampered by the lack of understanding of the mechanism of water electrolysis on perovskite surfaces. Key parameters that have been overlooked include the role of oxygen vacancies, B-O bond covalency, and redox activity of lattice oxygen species. Here we present a series of cobaltite perovskites where the covalency of the Co-O bond and the concentration of oxygen vacancies are controlled through Sr2+ substitution into La1-xSrxCoO3-δ. We attempt to rationalize the high activities of La1-xSrxCoO3-δ through the electronic structure and participation of lattice oxygen in the mechanism of water electrolysis as revealed through ab initio modelling. Using this approach, we report a material, SrCoO2.7, with a high, room temperature-specific activity and mass activity towards alkaline water electrolysis.

  18. The micro-electrolysis technique in waste water treatment

    International Nuclear Information System (INIS)

    The micro-electrolysis is one of the efficient methods to treat some kinds of waste water. The experiments have shown its high efficiency in sewage treatment and some kinds of industrial waste water. It is suitable for pre-treatment of high concentrated waste water and deep treatment of waste water for reuse purpose. The disadvantage of micro-electrolysis is its high energy consumption in case of high electrolyte concentration. (author) 2 figs., 11 tabs., 2 refs

  19. Alkaline electrolysis cell at high temperature and pressure of 250 °C and 42 bar

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2013-01-01

    A new type of alkaline electrolysis cells with nickel foam based gas diffusion electrodes and KOH (aq) immobilized in mesoporous SrTiO3 has been developed and tested at temperatures and pressures up to 250 °C and 42 bar, respectively. Current densities of 1.0 A cm−2 have been measured at a cell...... voltage of 1.5 V without the use of expensive noble metal catalysts. High electrical efficiency and current density combined with relatively small production costs may lead to both reduced investment and operating costs for hydrogen and oxygen production....

  20. On the production of hydrogen via alkaline electrolysis during off-peak periods

    International Nuclear Information System (INIS)

    This article studies the opportunity for producing hydrogen via alkaline electrolysis from electricity consumption during off-peak periods. Two aspects will be discussed: electricity spot markets and nuclear electricity production in France. From a market point of view, when there is a significant fluctuation in electricity prices, the use of an electrolysis installation during off-peak periods makes it possible to make quite considerable savings in production costs. Savings vary enormously from one market to the next; some highly fluctuating markets offer very low off-peak prices and allow for viable hydrogen production, even if average electricity prices first appear to be quite high. Very fluctuating spot prices market may be difficult to predict and makes operations of an electrolysis installation more complicated and risky. For other more stable markets, the use of an electrolysis installation during off-peak periods does not appear to be a relevant proposition. From the point of view of French electricity production, the availability of current nuclear power plants and the estimation of available energy for mass production of hydrogen show that the installations studied would not be viable. For 'peak period' use, it would certainly be more useful to have electrolysers with a lower investment proportion, even if this means slightly higher operating costs. Research into large-capacity electrolysers should, therefore, both develop low-production-cost electrolysers, for use in base load mode where dedicated production means are concerned, and highly flexible electrolysers, with low investment costs, which could easily be viable with low rates of use. (authors)

  1. Composite membranes for alkaline electrolysis based on polysulfone and mineral fillers

    Science.gov (United States)

    Burnat, Dariusz; Schlupp, Meike; Wichser, Adrian; Lothenbach, Barbara; Gorbar, Michal; Züttel, Andreas; Vogt, Ulrich F.

    2015-09-01

    Mineral-based membranes for high temperature alkaline electrolysis were developed by a phase inversion process with polysulfone as binder. The long-term stability of new mineral fillers: wollastonite, forsterite and barite was assessed by 8000 h-long leaching experiments (5.5 M KOH, 85 °C) combined with thermodynamic modelling. Barite has released only 6.22 10-4 M of Ba ions into the electrolyte and was selected as promising filler material, due to its excellent stability. Barite-based membranes, prepared by the phase inversion process, were further studied. The resistivity of these membranes in 5.5 M KOH was investigated as a function of membrane thickness and total porosity, hydrodynamic porosity as well as gas purities determined by conducting electrolysis at ambient conditions. It was found that a dense top layer resulting from the phase inversion process, shows resistivity values up to 451.0 ± 22 Ω cm, which is two orders of magnitude higher than a porous bulk membrane microstructure (3.89 Ω cm). Developed membranes provided hydrogen purity of 99.83 at 200 mA cm-2, which is comparable to previously used chrysotile membranes and higher than commercial state-of-the-art Zirfon 500utp membrane. These cost-effective polysulfone - barite membranes are promising candidates as asbestos replacement for commercial applications.

  2. Solid oxide electrolysis cell for decomposition of tritiated water

    International Nuclear Information System (INIS)

    The decomposition of tritiated water vapor with solid oxide electrolysis cell was proposed for the application to the D-T fusion reactor system. This method is essentially free from problems such as large tritium inventory, radiation damage, and generation of solid waste, so it is expected to be a promising one. Electrolysis of water vapor in argon carrier was performed using tube-type stabilized zirconia cell with porous platinum electrodes in the temperature range of 5000C to 9500C. High conversion ratio from water to hydrogen up to 99.9% was achieved. The characteristics of the cell is deduced from the Nernst's equation and conversion ratio is described as the function of the open circuit voltage. Experimental results agreed with the equation. Isotope effect in electrolysis is also discussed and experiments with heavy water were carried out. Obtained separation factor was slightly higher than the theoretical value

  3. Rare metal fission products in nuclear spent fuel as catalysts for hydrogen production by water electrolysis

    International Nuclear Information System (INIS)

    Separation and utilization of rare metal fission products (RMFP) in nuclear spent fuel were studied to apply them as a catalyst for hydrogen generation by water electrolysis. The RMFP, namely Pd, Ru, Rh and Tc, etc, are abundant, more than ca. 30kg per metric ton of a typical fast reactor spent fuel. The RMFP can be selectively separated from high level liquid waste (HLLW) by catalytic electrolytic extraction (CEE) method. Specific metallic cations such as Pd2+, which originate in the solutions, may act as promoters (i.e., Pdadatom) or mediators, thereby accelerating electrochemical deposition of RuNO3+, Rh3+ and ReO4- (simulator TcO4-). In utilizing CEE method, electrodeposited electrodes were prepared, and successively dedicated to the water (alkaline or artificial sea water) electrolysis tests. Among the RMFP deposited electrodes, maximum potential shifting for hydrogen evolution to noble side was observed for the quaternary, Pd-Ru-Rh-Re (3.5:4:1:1), deposit Pt electrode, with suggesting the highest cathodic currents for hydrogen evolution both in alkaline solution and artificial sea water. The electro analytic activity of quaternary, Pd-Ru-Rh-Re (3.5:4:1:1), deposit Pt electrode exceeded that of Pt electrode by ca. twice both in alkaline solution and artificial sea water. The paper conclusively proposes RMFP generated by nuclear fission to utilize as an alternative material for hydrogen production with a novel vision to bridge nuclear and hydrogen energy systems. (author)

  4. Water Electrolysis for In-Situ Resource Utilization (ISRU)

    Science.gov (United States)

    Lee, Kristopher A.

    2016-01-01

    Sending humans to Mars for any significant amount of time will require capabilities and technologies that enable Earth independence. To move towards this independence, the resources found on Mars must be utilized to produce the items needed to sustain humans away from Earth. To accomplish this task, NASA is studying In Situ Resource Utilization (ISRU) systems and techniques to make use of the atmospheric carbon dioxide and the water found on Mars. Among other things, these substances can be harvested and processed to make oxygen and methane. Oxygen is essential, not only for sustaining the lives of the crew on Mars, but also as the oxidizer for an oxygen-methane propulsion system that could be utilized on a Mars ascent vehicle. Given the presence of water on Mars, the electrolysis of water is a common technique to produce the desired oxygen. Towards this goal, NASA designed and developed a Proton Exchange Membrane (PEM) water electrolysis system, which was originally slated to produce oxygen for propulsion and fuel cell use in the Mars Atmosphere and Regolith COllector/PrOcessor for Lander Operations (MARCO POLO) project. As part of the Human Exploration Spacecraft Testbed for Integration and Advancement (HESTIA) project, this same electrolysis system, originally targeted at enabling in situ propulsion and power, operated in a life-support scenario. During HESTIA testing at Johnson Space Center, the electrolysis system supplied oxygen to a chamber simulating a habitat housing four crewmembers. Inside the chamber, oxygen was removed from the atmosphere to simulate consumption by the crew, and the electrolysis system's oxygen was added to replenish it. The electrolysis system operated nominally throughout the duration of the HESTIA test campaign, and the oxygen levels in the life support chamber were maintained at the desired levels.

  5. Investigation of Coliform Removal from Drinking Water by Electrolysis

    OpenAIRE

    Rahmani, A; M.R Samarghandi

    2008-01-01

    Introduction & Objective: The practice of eliminating pathogenic microorganisms in water dates back to ancient times. The most common methods for water disinfection are using chemicals, Ozonation, Ultra Violet ray, Membrane Processes and etc. There has been considerable interest in disinfection of water by using electrochemical methods in recent years. The main purpose of this study is to conduct experimental investigation of water disinfection by using the electrolysis method. Inactivation a...

  6. Carbon dioxide and water vapor high temperature electrolysis

    Science.gov (United States)

    Isenberg, Arnold O.; Verostko, Charles E.

    1989-01-01

    The design, fabrication, breadboard testing, and the data base obtained for solid oxide electrolysis systems that have applications for planetary manned missions and habitats are reviewed. The breadboard tested contains sixteen tubular cells in a closely packed bundle for the electrolysis of carbon dioxide and water vapor. The discussion covers energy requirements, volume, weight, and operational characteristics related to the measurement of the reactant and product gas compositions, temperature distribution along the electrolyzer tubular cells and through the bundle, and thermal energy losses. The reliability of individual cell performance in the bundle configuration is assessed.

  7. Development status of a preprototype water electrolysis subsystem

    Science.gov (United States)

    Martin, R. B.; Erickson, A. C.

    1981-01-01

    A preprototype water electrolysis subsystem was designed and fabricated for NASA's advanced regenerative life support program. A solid polymer is used for the cell electrolyte. The electrolysis module has 12 cells that can generate 5.5 kg/day of oxygen for the metabolic requirements of three crewmembers, for cabin leakage, and for the oxygen and hydrogen required for carbon dioxide collection and reduction processes. The subsystem can be operated at a pressure between 276 and 2760 kN/sq m and in a continuous constant-current, cyclic, or standby mode. A microprocessor is used to aid in operating the subsystem. Sensors and controls provide fault detection and automatic shutdown. The results of development, demonstration, and parametric testing are presented. Modifications to enhance operation in an integrated and manned test are described. Prospective improvements for the electrolysis subsystem are discussed.

  8. Analysis of cavitation effect for water purifier using electrolysis

    Science.gov (United States)

    Shin, Dong Ho; Ko, Han Seo; Lee, Seung Ho

    2015-11-01

    Water is a limited and vital resource, so it should not be wasted by pollution. A development of new water purification technology is urgent nowadays since the original and biological treatments are not sufficient. The microbubble-aided method was investigated for removal of algal in this study since it overcomes demerits of the existing purification technologies. Thus, the cavitation effect in a venturi-type tube using the electrolysis was analyzed. Ruthenium-coated titanium plates were used as electrodes. Optimum electrode interval and applied power were determined for the electrolysis. Then, the optimized electrodes were installed in the venturi-type tube for generating cavitation. The cavitation effect could be enhanced without any byproduct by the bubbly flow induced by the electrolysis. The optimum mass flow rate and current were determined for the cavitation with the electrolysis. Finally, the visualization techniques were used to count the cell number of algal and microbubbles for the confirmation of the performance. As a result, the energy saving and high efficient water purifier was fabricated in this study. This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Korean government (MEST) (No. 2013R1A2A2A01068653).

  9. Development of a pressurized bipolar alkaline water electrolyzer

    Energy Technology Data Exchange (ETDEWEB)

    Neves Junior, Newton Pimenta; Pinto, Edgar A. de Godoi Rodrigues; Silva, Ennio Peres da; Rapelli, Rubia; Pinto, Cristiano da Silva [Universidade Estadual de Campinas (DFA/ IFGW/UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin. Dept. de Fisica Aplicada], Email: nevesjr@unicamp.br; Marin Neto, Antonio Jose; Lopes, Daniel Gabriel; Camargo, Joao Carlos; Ferreira, Paulo F.P. [Hydrogen Technology (HyTron), Campinas, SP (Brazil); Furlan, Andre Luis [Universidade Estadual de Campinas (DE/FEC/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica

    2010-07-01

    This paper reports the actual development status of a bipolar alkaline water electrolyzer with maximum production capacity of 1 m3/h of hydrogen and controlled by a PLC (Programmable Logic Controller), which also interfaces the electrolytic system with operators and other equipment, such as gas storage tanks, fuel cells and photovoltaic panels. The project also includes the construction of an electrolysis test bench to record electrical parameters (cathode, anode, separator and electrolyte potentials), the amount of produced gases and gas quality determined by gas chromatography. (author)

  10. Hydrogen production by high-temperature electrolysis of water vapor steam. Test results obtained with an electrolysis tube

    International Nuclear Information System (INIS)

    High-temperature electrolysis of water vapor steam is an advanced hydrogen production process decomposing high temperature steam up to 1,000degC, which applies an electro-chemical reaction reverse to the solid oxide fuel cell. At Japan Atomic Energy Research Institute, laboratory-scale experiments have been conducted using a practical electrolysis tube with 12 electrolysis cells in order to develop heat utilization systems for high-temperature gas-cooled reactors. The electrolysis cells of which electrolyte was yttria-stabilized zirconia were formed on a porous ceramic tube in series by plasma spraying. In the experiments, water steam mixed with argon carrier gas was supplied into the electrolysis tube heated at a constant temperature regulated in the range from 850degC to 950degC, and electrolysis power was supplied by a DC power source. Hydrogen production rate increased with applied voltage and electrolysis temperature; the maximum production rate was 6.9Nl/h at 950degC. Hydrogen production rate was correlated with applied current densities on the basis of experimental data. High energy efficiency was achieved under the applied current density ranging from 80 to 100 mA/cm2. (author)

  11. Process intensification: water electrolysis in a centrifugal acceleration field

    OpenAIRE

    Lao, Liyun; Ramshaw, C.; Yeung, Hoi

    2011-01-01

    Intensification of hydrogen production by carrying out water electrolysis in a centrifugal acceleration field has been demonstrated. A prototype single cell rotary water electrolyser was constructed, and a number of design challenges with regard to the practical application were addressed. The rotary electrolyser was tested over a range of current density, centrifugal acceleration, electrolyte concentration, temperature, and electrode geometry. The test results showed that a...

  12. Bipolar electrolysis for tritium recovery from weakly active tritiated water

    International Nuclear Information System (INIS)

    Detritiation facilities produce low activity tritiated water from which tritium cannot be recovered. Bipolar electrolysis, based on the electrochemical permeation of hydrogen and its isotopes through Pd-Ag alloy membranes, allows tritiated water enrichment together with negligible gaseous tritium release. Our purpose is to enrich water from 500 Ci/l (1.85x1013 Bq/l) to more than 2000 Ci/l (7.40x1013 Bq/l). We first describe the principle of bipolar electrolysis and its application to isotopic enrichment. The experimental part of this work consists of the determination of the isotopic separation factors. From these experimental values, we simulated the working of an operational cell and we demonstrate the feasibility of the process

  13. Production of hydrogen using composite membrane in PEM water electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Santhi priya, E.L.; Mahender, C.; Mahesh, Naga; Himabindu, V. [Centre for Environment, Institute of Science and Technology, Jawaharlal Nehru Technological University Hyderabad, Kukatpally, Hyderabad-500 085, A.P (India); Anjaneyulu, Y. [Director, TLGVRC, JSU Box 18739, JSU, Jackson, MS 32917-0939 (United States)

    2012-07-01

    Electrolysis of water is the best known technology till today to produce hydrogen. The only practical way to produce hydrogen using renewable energy sources is by proton exchange membrane (PEM) water electrolysis. The most commonly used PEM membrane is Nafion. Composite membrane of TiO2 is synthesized by casting method using Nafion 5wt% solution. RuO2 is used as anode and 10 wt% Pd on activated carbon is used as cathode in the water electrolyser system. The performance of this Composite membrane is studied by varying voltage range 1.8 to 2.6V with respect to hydrogen yield and at current density 0.1, 0.2, 0.3, 0.4, and 0.5(A cm-2). This Composite membrane has been tested using in-house fabricated single cell PEM water electrolysis cell with 10cm2 active area at temperatures ranging from 30,45,65 850c and at 1 atmosphere pressure.

  14. Production of Electrolysis-Purity Water Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Removal of impurities from water has been studied extensively by NASA in the context of water recovery from wastewater. However, the Water Recovery System and Urine...

  15. Water electrolysis with a conducting carbon cloth: subthreshold hydrogen generation and superthreshold carbon quantum dot formation.

    Science.gov (United States)

    Biswal, Mandakini; Deshpande, Aparna; Kelkar, Sarika; Ogale, Satishchandra

    2014-03-01

    A conducting carbon cloth, which has an interesting turbostratic microstructure and functional groups that are distinctly different from other ordered forms of carbon, such as graphite, graphene, and carbon nanotubes, was synthesized by a simple one-step pyrolysis of cellulose fabric. This turbostratic disorder and surface chemical functionalities had interesting consequences for water splitting and hydrogen generation when such a cloth was used as an electrode in the alkaline electrolysis process. Importantly, this work also gives a new twist to carbon-assisted electrolysis. During electrolysis, the active sites in the carbon cloth allow slow oxidation of its surface to transform the surface groups from COH to COOH and so forth at a voltage as low as 0.2 V in a two-electrode system, along with platinum as the cathode, instead of 1.23 V (plus overpotential), which is required for platinum, steel, or even graphite anodes. The quantity of subthreshold hydrogen evolved was 24 mL cm(-2)  h(-1) at 1 V. Interestingly, at a superthreshold potential (>1.23 V+overpotential), another remarkable phenomenon was found. At such voltages, along with the high rate and quantity of hydrogen evolution, rapid exfoliation of the tiny nanoscale (5-7 nm) units of carbon quantum dots (CQDs) are found in copious amounts due to an enhanced oxidation rate. These CQDs show bright-blue fluorescence under UV light. PMID:24492961

  16. Tritium separation from light and heavy water by bipolar electrolysis

    International Nuclear Information System (INIS)

    Use of bipolar electrolysis with countercurrent electrolyte flow to separate hydrogen isotopes was investigated for the removal of tritium from light water effluents or from heavy water moderator. Deuterium-tritium and protium-tritium separation factors occurring on a Pd-25% Ag bipolar electrode were measured to be 2.05 to 2.16 and 11.6 to 12.4 respectively, at current densities between 0.21 and 0.50 A cm-2, and at 35 to 900C. Current densities up to 0.3 A cm-2 have been achieved in continuous operation, at 80 to 900C, without significant gas formation on the bipolar electrodes. From the measured overvoltage at the bipolar electrodes and the electrolyte conductivity the power consumption per stage was calculated to be 3.0 kwh/kg H2O at 0.2 A cm-2 and 5.0 kwh/kg H2O at 0.5 A cm-2 current density, compared to 6.4 and 8.0 kwh/kg H2O for normal electrolysis. A mathematical model derived for hydrogen isotope separation by bipolar electrolysis, i.e., for a square cascade, accurately describes the results for protium-tritium separation in two laboratory scale, multistage experiments with countercurrent electrolyte flow; the measured tiritum concentration gradient through the cascade agreed with the calculated values

  17. Electrolysis of water on (oxidized) metal surfaces

    DEFF Research Database (Denmark)

    Rossmeisl, Jan; Logadottir, Ashildur; Nørskov, Jens Kehlet

    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 bia...

  18. Electrocatalysis in Water Electrolysis with Solid Polymer Electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Rasten, Egil

    2001-10-01

    Development and optimization of the electrodes in a water electrolysis system using a polymer membrane as electrolyte have been carried out in this work. A cell voltage of 1.59 V (energy consumption of about 3.8 kWh/Nm{sub 3} H{sub 2}) has been obtained at practical operation conditions of the electrolysis cell (10 kA . m2, 90{sup o}C) using a total noble metal loading of less than 2.4 mg.cm{sub 2} and a Nafion -115 membrane. It is further shown that a cell voltage of less than 1.5 V is possible at the same conditions by combination of the best electrodes obtained in this work. The most important limitation of the electrolysis system using polymer membrane as electrolyte has proven to be the electrical conductivity of the catalysts due to the porous backing/current collector system, which increases the length of the current path and decreases the cross section compared to the apparent one. A careful compromise must therefore be obtained between electrical conductivity and active surface area, which can be tailored by preparation and annealing conditions of the metal oxide catalysts. Anode catalysts of different properties have been developed. The mixed oxide of Ir-Ta (85 mole% Ir) was found to exhibit highest voltage efficiency at a current density of 10 kA.m{sub 2} or below, whereas the mixed oxide of Ir and Ru (60-80 mole% Ir) was found to give the highest voltage efficiency for current densities of above 10 kA.m{sub 2}. Pt on carbon particles, was found to be less suitable as cathode catalyst in water electrolysis. The large carbon particles introduced an unnecessary porosity into the catalytic layer, which resulted in a high ohmic drop. Much better voltage efficiency was obtained by using Pt-black as cathode catalyst, which showed a far better electrical conductivity. Ru-oxide as cathode catalyst in water electrolysis systems using a polymer electrolyte was not found to be of particular interest due to insufficient electrochemical activity and too low

  19. Development of Non-Platinum Catalysts for Intermediate Temperature Water Electrolysis

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey Valerievich; Petrushina, Irina Michailovna; Bjerrum, Niels J.

    2014-01-01

    Water electrolysis is recognized as an efficient energy storage (in the form of hydrogen) supplement in renewable energy production. However, industrial alkaline water electrolyzers are rather ineffective and space requiring for a commercial use in connection with energy storage. The most effective...... the best compromise in metal-hydrogen bond strength1,2. Due to economic reasons there is a huge interest in replacing Pt by cheaper alternatives and much effort have been made in finding novel catalysts for Hydrogen Evolution Reaction (HER)3,4. Many anhydrous proton conductors have been investigated...... it is important to simulate conditions of those presented in the assembled operational electrolyzer. In this work a molten KH2PO4 will be used as an electrolyte while screening performance of various transition metals and their carbides at higher temperature (Figure 1). In this work will be shown...

  20. Development of a solid polymer electrolyte electrolysis cell module and ancillary components for a breadboard water electrolysis system

    Science.gov (United States)

    Porter, F. J., Jr.

    1972-01-01

    Solid polymer electrolyte technology in a water electrolysis system along with ancillary components to generate oxygen and hydrogen for a manned space station application are considered. Standard commercial components are utilized wherever possible. Presented are the results of investigations, surveys, tests, conclusions and recommendations for future development efforts.

  1. Electrolysis of Water in the Secondary School Science Laboratory with Inexpensive Microfluidics

    Science.gov (United States)

    Davis, T. A.; Athey, S. L.; Vandevender, M. L.; Crihfield, C. L.; Kolanko, C. C. E.; Shao, S.; Ellington, M. C. G.; Dicks, J. K.; Carver, J. S.; Holland, L. A.

    2015-01-01

    This activity allows students to visualize the electrolysis of water in a microfluidic device in under 1 min. Instructional materials are provided to demonstrate how the activity meets West Virginia content standards and objectives. Electrolysis of water is a standard chemistry experiment, but the typical laboratory apparatus (e.g., Hoffman cell)…

  2. Alkaline Water and Longevity: A Murine Study

    Science.gov (United States)

    Magro, Massimiliano; Corain, Livio; Ferro, Silvia; Baratella, Davide; Bonaiuto, Emanuela; Terzo, Milo; Corraducci, Vittorino; Salmaso, Luigi; Vianello, Fabio

    2016-01-01

    The biological effect of alkaline water consumption is object of controversy. The present paper presents a 3-year survival study on a population of 150 mice, and the data were analyzed with accelerated failure time (AFT) model. Starting from the second year of life, nonparametric survival plots suggest that mice watered with alkaline water showed a better survival than control mice. Interestingly, statistical analysis revealed that alkaline water provides higher longevity in terms of “deceleration aging factor” as it increases the survival functions when compared with control group; namely, animals belonging to the population treated with alkaline water resulted in a longer lifespan. Histological examination of mice kidneys, intestine, heart, liver, and brain revealed that no significant differences emerged among the three groups indicating that no specific pathology resulted correlated with the consumption of alkaline water. These results provide an informative and quantitative summary of survival data as a function of watering with alkaline water of long-lived mouse models. PMID:27340414

  3. Cobalt and molybdenum activated electrodes in foam based alkaline electrolysis cells at 150-250 °C and 40 bar

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    A new type of alkaline electrolysis cells with nickel foam based gas diffusion electrodes and KOH (aq) immobilized in mesoporous SrTiO3 has been developed and tested at temperatures of 150 C, 200 C and 250 C at a pressure of 40 bar. Two cells have been characterized during the 270 h long test...

  4. Advancements in water vapor electrolysis technology. [for Space Station ECLSS

    Science.gov (United States)

    Chullen, Cinda; Heppner, Dennis B.; Sudar, Martin

    1988-01-01

    The paper describes a technology development program whose goal is to develop water vapor electrolysis (WVE) hardware that can be used selectively as localized topping capability in areas of high metabolic activity without oversizing the central air revitalization system on long-duration manned space missions. The WVE will be used primarily to generate O2 for the crew cabin but also to provide partial humidity control by removing water vapor from the cabin atmosphere. The electrochemically based WVE interfaces with cabin air which is controlled in the following ranges: dry bulb temperature of 292 to 300 K; dew point temperature of 278 to 289 K; relative humidity of 25 to 75 percent; and pressure of 101 + or - 1.4 kPa. Design requirements, construction details, and results for both single-cell and multicell module testing are presented, and the preliminary sizing of a multiperson subsystem is discussed.

  5. Investigation of Coliform Removal from Drinking Water by Electrolysis

    Directory of Open Access Journals (Sweden)

    A. Rahmani

    2008-07-01

    Full Text Available Introduction & Objective: The practice of eliminating pathogenic microorganisms in water dates back to ancient times. The most common methods for water disinfection are using chemicals, Ozonation, Ultra Violet ray, Membrane Processes and etc. There has been considerable interest in disinfection of water by using electrochemical methods in recent years. The main purpose of this study is to conduct experimental investigation of water disinfection by using the electrolysis method. Inactivation and killing Coliform in polluted waters was investigated by different voltage, electrodes (Al, St and Cu and distance between electrodes.Materials & Methods: The polluted water was prepared by adding a colony of coliform growth on EMB in raw water. Experiments were done similarly via the same electrolyzes time, electrodes distance and voltage intensity for all types of combinations of electrodes respectively. Results: The experimental results show that the removal efficiency depends on the voltage and electrodes material. From the experiments carried out at 10 V. and at current intensity of 135 mA, it was found that five-minute period was sufficient for disinfecting water using Stainless Steel electrodes.Conclusion: Due to the results, the electrochemical methods can be proposed as a promising cleaning and purifying method for water disinfection.

  6. Efficiency of tritium measurement in the environmental water by electrolysis enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Koganezawa, T.; Iida, T. [Nagoya Univ., Graduate School of Engineering, Nagoya, Aichi (Japan); Sakuma, Y.; Yamanishi, H. [National Inst. for Fusion Science, Toki, Gifu (Japan); Ogata, Y. [Nagoya Univ., School of Health Sciences, Nagoya, Aichi (Japan); Tsuji, N. [Japan Air-conditioning Service Co. and Ltd., Nagoya, Aichi (Japan); Kakiuchi, M. [Gakushuin Univ., Faculty of Science, Tokyo (Japan); Satake, H. [Toyama Univ., Faculty of Science, Toyama (Japan)

    2002-06-01

    Now tritium concentration in the environmental water is 0.5-2 Bq{center_dot}L{sup -1} in Japan. Tritium concentration cannot be measured accurately by liquid scintillation method, because the minimum detectable limits of liquid scintillation method is 0.5 Bq{center_dot}L{sup -1}. Therefore, one needs to enrich tritium concentration in the environmental water. Although the most popular method for tritium enrichment is electrolysis, the electrolysis takes much time and labor for distilling sample water at before and after the electrolysis. The purpose of this study is to investigate the possibility of more convenient method for tritium measurement. The method substitutes filtration for distillation at before electrolysis and omits distillation at after electrolysis. The method enables by using the electrolysis with solid polymer electrode. We performed two kinds of experiment to confirm the possibility of the method. First, impurities eluted from electrolysis installation with ultra pure water as sample was measured. Some impurities were eluted into the sample, but they brought noneffective quenching. Secondly, we applied new method to the environmental waters. Substituting for distillation, two filtration, 0.1 {mu}m filtration and reverse osmosis method, were investigated. Impurities in the samples by the filtrations were somewhat higher than that by the distillation, they brought noneffective quenching. We, however, observed distemper of the electrolysis happened by electrolysing filtered sample. Distillation is substituted filtration at before enrichment and omitted at after enrichment, leaving the influence of quenching out of consideration. (author)

  7. Efficiency of tritium measurement in the environmental water by electrolysis enrichment

    International Nuclear Information System (INIS)

    Now tritium concentration in the environmental water is 0.5-2 Bq·L-1 in Japan. Tritium concentration cannot be measured accurately by liquid scintillation method, because the minimum detectable limits of liquid scintillation method is 0.5 Bq·L-1. Therefore, one needs to enrich tritium concentration in the environmental water. Although the most popular method for tritium enrichment is electrolysis, the electrolysis takes much time and labor for distilling sample water at before and after the electrolysis. The purpose of this study is to investigate the possibility of more convenient method for tritium measurement. The method substitutes filtration for distillation at before electrolysis and omits distillation at after electrolysis. The method enables by using the electrolysis with solid polymer electrode. We performed two kinds of experiment to confirm the possibility of the method. First, impurities eluted from electrolysis installation with ultra pure water as sample was measured. Some impurities were eluted into the sample, but they brought noneffective quenching. Secondly, we applied new method to the environmental waters. Substituting for distillation, two filtration, 0.1 μm filtration and reverse osmosis method, were investigated. Impurities in the samples by the filtrations were somewhat higher than that by the distillation, they brought noneffective quenching. We, however, observed distemper of the electrolysis happened by electrolysing filtered sample. Distillation is substituted filtration at before enrichment and omitted at after enrichment, leaving the influence of quenching out of consideration. (author)

  8. Water electrolysis-induced optical degradation of aluminum-doped zinc oxide films

    International Nuclear Information System (INIS)

    A type of optical degradation of aluminium-doped zinc oxide (AZO) films due to water electrolysis-induced reduction reaction was reported. An experiment was designed in which AZO films were immersed in a 0.01 M NaOH aqueous solution as cathode to electrolyze water. Significant decreases in the optical transmission of the treated samples were observed. Studies by X-ray diffraction and scanning electron microscope showed that the degradation of AZO films was due to compositional and structural changes with the treatment of water electrolysis, which resulted from the reduction reaction of atomic hydrogen generated in the electrolysis of water. This optical degradation reflects the stability degradation of AZO films under water electrolysis environment

  9. Preliminary testing of an electrolysis cell for highly tritiated water

    International Nuclear Information System (INIS)

    In the framework of the European fusion technology programme, SCK/CEN (Mol, Belgium) has continued the development of an electrolysis cell for highly tritiated water. In the resulting original concept, the liquid inventory is limited to the vertical porous gas separator which is wetted by capillarity. Use is made of thermoelectric heat pumps to cool the cell down to about 80C. Intensive testing with light water has been performed successfully during more than 10,000 cumulated hours with mock-up cells, and during more than 6,000 cumulated hours with a prototype cell. These tests have demonstrated the robustness and the long-term reliability of the proposed system. Further experiments are going on with the aim to characterize the working of the capillary cell. In the same time, peripheral equipment such as demisters and cold traps are being tested. These devices are to be incorporated in a dedicated loop for testing with tritiated water at the nominal specific activity (-- 4.1019 Bq/m3)

  10. A Demonstration of Carbon-Assisted Water Electrolysis

    Directory of Open Access Journals (Sweden)

    Olalekan D. Adeniyi

    2013-03-01

    Full Text Available It is shown that carbon fuel cell technology can be combined with that of high temperature steam electrolysis by the incorporation of carbon fuel at the cell anode, with the resulting reduction of the required electrolysis voltage by around 1 V. The behaviour of the cell current density and applied voltage are shown to be connected with the threshold of electrolysis and the main features are compared with theoretical results from the literature. The advantage arises from the avoidance of efficiency losses associated with electricity generation using thermal cycles, as well as the natural separation of the carbon dioxide product stream for subsequent processing.

  11. Fundamentals of SO2 depolarized water electrolysis and challenges of materials used

    OpenAIRE

    Lokkiluoto, Anu

    2013-01-01

    Sulfur dioxide depolarized water electrolysis (SDE) produces sulfuric acid and hydrogen. Due to its lower cell voltage, the process requires far less electricity than traditional water electrolysis. When SO2 is obtained from flash smelting, sulfides roasting, sulfur combustion, or any other similar operation, SDE is a part of the OutotecR open cycle process. In the present work, materials to be used in SDE were studied together with the fundamentals of the process. Data on the co-productio...

  12. Technoeconomic analysis of a methanol plant Based on gasification of biomass and Electrolysis of water

    OpenAIRE

    Clausen, Lasse R.; Houbak, Niels; Elmegaard, Brian

    2010-01-01

    Abstract Methanol production process configurations based on renewable energy sources have been designed. The processes were analyzed in the thermodynamic process simulation tool DNA. The syngas used for the catalytic methanol production was produced by gasification of biomass, electrolysis of water, CO2 from post-combustion capture and autothermal reforming of natural gas or biogas. Underground gas storage of hydrogen and oxygen was used in connection with the electrolysis to enab...

  13. Fission product recycling as catalysts for hydrogen production by water electrolysis

    International Nuclear Information System (INIS)

    An electrolytic extraction method has been studied to separate fission products (Ru, Rh, Pd, Tc, Se, Te, etc) from the nuclear spent fuel. Yet they are rare metal fission products (RMFP), most are long-lived (LLFP; Pd, Tc, Se, Te). In the applied separation process, Pd2+ cation itself would not only be easily deposited from various nitric acid solutions, but enhance also the deposition of RuNO3+ and ReO4- by acting as a catalyst (as Pdadatom). Such Catalytic Electrolytic Extraction (CEE) method was found to be applicable in the case of TcO4- deposition, too. The quaternary-, Pd-Ru-Rh-Re, deposit on the Pt electrodes show the highest cathodic current, ca twice superior to that of the Pt electrode both in artificial sea water as well as in alkaline solution. The promising utilization of RMFP will be as 'FP-catalyst' for hydrogen production by water electrolysis. RMFP would be circulating material to bridge nuclear and hydrogen energy systems. (author)

  14. Combined Electrolysis and Catalytic Exchange (CECE) upgraders - an alternative to Water Distillation (DW) heavy water upgraders

    International Nuclear Information System (INIS)

    All operating CANDU stations are equipped with Water Distillation (DW) systems for heavy water upgrading. An alternative process, Combined Electrolysis and Catalytic Exchange (CECE), is being considered for use in future CANDU stations. The CECE process has several operating advantages over DW systems, including lower emissions and heavy water losses. Changes in nuclear standards may change seismic requirements and classification of upgrader systems. These changes will likely increase the cost of heavy water upgraders, but the cost increase will be smaller for a CECE upgrader. Research at Chalk River Labs has identified materials for use in the CECE process that will not chemically or mechanically degrade when exposed to highly tritiated water. (author)

  15. Vanadium nanobelts coated nickel foam 3D bifunctional electrode with excellent catalytic activity and stability for water electrolysis

    Science.gov (United States)

    Yu, Yu; Li, Pei; Wang, Xiaofang; Gao, Wenyu; Shen, Zongxu; Zhu, Yanan; Yang, Shuliang; Song, Weiguo; Ding, Kejian

    2016-05-01

    Pursuit of highly active, stable and low-cost electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is the key point for large-scale water splitting. A vanadium nanobelts coating on a nickel foam (V/NF) is proposed as an excellent 3D bifunctional electrode for water electrolysis here, which exhibits high activities with overpotentials of 292 and 176 mV at 10 mA cm-2 for OER and HER, respectively. When employed as a bifunctional electrocatalyst in an alkaline water electrolyzer, a cell voltage of 1.80 V was required to achieve 20 mA cm-2 with a slight increase during a 24 h durability test. The existence of the appropriate amount of nitrogen and oxygen elements in the surface region of vanadium nanobelts is regarded to be responsible for the electrocatalytic activity.Pursuit of highly active, stable and low-cost electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is the key point for large-scale water splitting. A vanadium nanobelts coating on a nickel foam (V/NF) is proposed as an excellent 3D bifunctional electrode for water electrolysis here, which exhibits high activities with overpotentials of 292 and 176 mV at 10 mA cm-2 for OER and HER, respectively. When employed as a bifunctional electrocatalyst in an alkaline water electrolyzer, a cell voltage of 1.80 V was required to achieve 20 mA cm-2 with a slight increase during a 24 h durability test. The existence of the appropriate amount of nitrogen and oxygen elements in the surface region of vanadium nanobelts is regarded to be responsible for the electrocatalytic activity. Electronic supplementary information (ESI) available: More SEM, TEM images, XRD patterns, LSV curves, XPS spectra. See DOI: 10.1039/c6nr02395a

  16. Zirfon® as Separator Material for Water Electrolysis Under Specific Conditions

    Science.gov (United States)

    Lavorante, María José; Franco, Juan Isidro; Bonelli, Pablo; Imbrioscia, Gerardo Martín; Fasoli, Héctor José

    Hydrogen production through alkaline water electrolysis requires improvements to use renewable energy more efficiently. In the process of converting electrical to chemical energy, efforts are focused on reducing energy loss. Electrolysers play two important roles in this process: one of them is as a hydrogen producer and the other is as a storage mechanism. A storage mechanism occurs when there is an excess of renewable energy that can be stored in the form of hydrogen (chemical energy), which is the fuel for the following step, turning chemical into electrical energy again. Electrolysers research is focused on: separators and electrodes materials, electrolytic solutions and cell design. The ideal situation for a separator in an electrolyser is to possess low electric resistance. For that purpose, we compared Zirfon®, silicone and the system without separator. This work studied the behaviour of Zirfon® under specific working conditions: room temperature, an electrolytic solution of potassium hydroxide 35 % w/w and five different distances between electrodes. In order to carry out this experiment, we designed and constructed a special electrolytic cell. The experimental results showed that Zirfon® separator increases the system resistance approximately 15 % when compared to the same system without separator, but it reduces resistance when compared to silicone (excellent insulator). Another result proved that the distances between electrodes proposed in this work did not show bubbles resistance because the system performance improved as the distance became shorter.

  17. Thermodynamic evaluation of geothermal energy powered hydrogen production by PEM water electrolysis

    International Nuclear Information System (INIS)

    Thermodynamic energy and exergy analysis of a PEM water electrolyzer driven by geothermal power for hydrogen production is performed. For this purpose, work is produced from a geothermal resource by means of the organic Rankine cycle; the resulting work is used as a work input for an electrolysis process; and electrolysis water is preheated by the waste geothermal water. The first and second-law based performance parameters are identified for the considered system and the system performance is evaluated. The effects of geothermal water and electrolysis temperatures on the amount of hydrogen production are studied and these parameters are found to be proportional to each other. We consider a geothermal resource at 160 °C available at a rate of 100 kg/s. Under realistic operating conditions, 3810 kW power can be produced in a binary geothermal power plant. The produced power is used for the electrolysis process. The electrolysis water can be preheated to 80 °C by the geothermal water leaving the power plant and hydrogen can be produced at a rate of 0.0340 kg/s. The energy and exergy efficiencies of the binary geothermal power plant are 11.4% and 45.1%, respectively. The corresponding efficiencies for the electrolysis system are 64.0% and 61.6%, respectively, and those for the overall system are 6.7% and 23.8%, respectively. - Highlights: • Thermodynamic analysis of hydrogen production by PEM electrolysis powered by geothermal energy. • Power is used for electrolyser; used geothermal water is for preheating electrolysis water. • Effect of geothermal water and electrolysis temperatures on the amount of hydrogen production. • Hydrogen can be produced at a rate of 0.0340 kg/s for a resource at 160 °C available at 100 kg/s. • Energy and exergy efficiencies of the overall system are 6.7% and 23.8%, respectively

  18. Alkalinity in oil field waters - what alkalinity is and how it is measured

    International Nuclear Information System (INIS)

    The alkalinity is an important parameter in the description of pH-behaviour, buffer capacity and scaling potentials in oil field waters. Although the alkalinity is widely used, it seems to be considerable confusion in connection with the concept. It is often used incorrectly and different authors define the concept in different ways. Several different methods for the determination of alkalinity can be found in the literature. This paper discusses the definition of alkalinity and how to use alkalinity in oil field waters to obtain data of importance for scale and pH predictions. There is also shown how a simple titration of oil field waters can give both the alkalinity and the content of organic acids in these waters. It is obvious from these findings that most of the methods used to day may give considerable errors when applied to oil field waters with high contents of organic acids. 8 refs., 8 figs., 5 tabs

  19. Solid polymer electrolyte water electrolysis system development. [to generate oxygen for manned space station applications

    Science.gov (United States)

    1975-01-01

    Solid polymer electrolyte technology used in a water electrolysis system (WES) to generate oxygen and hydrogen for manned space station applications was investigated. A four-man rated, low pressure breadboard water electrolysis system with the necessary instrumentation and controls was fabricated and tested. A six man rated, high pressure, high temperature, advanced preprototype WES was developed. This configuration included the design and development of an advanced water electrolysis module, capable of operation at 400 psig and 200 F, and a dynamic phase separator/pump in place of a passive phase separator design. Evaluation of this system demonstrated the goal of safe, unattended automated operation at high pressure and high temperature with an accumulated gas generation time of over 1000 hours.

  20. Water electrolysis for hydrogen production in Brazilian perspective

    Energy Technology Data Exchange (ETDEWEB)

    Saliba-Silva, Adonis Marcelo; Carvalho, Fatima M.S.; Bergamaschi, Vanderlei Sergio; Linardi, Marcelo [Instituto de Pesquisas Energeticas e Nucleares (CCCH/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Fuel Cell and Hydrogen Center], Email: saliba@ipen.br

    2009-07-01

    Hydrogen is a promising energy carrier, which potentially could replace the fossil fuels used in the transportation and distributed energy sector of Brazilian economy. Fossil fuels are polluting by carbogenic emissions from their combustion, being so co-responsible for present global warming. However, no large scale, cost-effective, environmentally non-carbogenic hydrogen production process is currently available for commercialization. There are feasible possibilities to use electrolysis as one of the main sources of hydrogen, especially thinking on combination with renewable sources of energy, mainly eolic and solar. In this work some perspectives for Brazilian energy context is presented, where electrolysis combined with renewable power source and fuel cell power generation would be a good basis to improve the distributed energy supply for remote areas, where the electricity grid is not present or is deficient. (author)

  1. Effects of low voltage electrolysis and freezing on coliform content of contaminated water

    International Nuclear Information System (INIS)

    A sewage sample was mixed with drinking water and subjected to low voltage (15V) electrolysis in the presence of 1% NaCl. The prepared sample was also kept in freezer with and without the presence of sodium chloride for 4-hours. Among these treatments the electrolysis proved to kill the coliforms, while the freezing reduced the bacterial content. Antibiotics sensitivity patterns revealed that certain of the coliform strains survived the freezing and thawing shocks. Nature of such surviving bacteria and need to study chemical parameters of electrolyzed water are discussed. (author)

  2. THERMODYNAMIC CONSIDERATIONS FOR THERMAL WATER SPLITTING PROCESSES AND HIGH TEMPERATURE ELECTROLYSIS

    Energy Technology Data Exchange (ETDEWEB)

    J. E. O' Brien

    2008-11-01

    A general thermodynamic analysis of hydrogen production based on thermal water splitting processes is presented. Results of the analysis show that the overall efficiency of any thermal water splitting process operating between two temperature limits is proportional to the Carnot efficiency. Implications of thermodynamic efficiency limits and the impacts of loss mechanisms and operating conditions are discussed as they pertain specifically to hydrogen production based on high-temperature electrolysis. Overall system performance predictions are also presented for high-temperature electrolysis plants powered by three different advanced nuclear reactor types, over their respective operating temperature ranges.

  3. Technoeconomic analysis of a methanol plant based on gasification of biomass and electrolysis of water

    DEFF Research Database (Denmark)

    Clausen, Lasse Røngaard; Houbak, N.; Elmegaard, Brian

    2010-01-01

    Methanol production process configurations based on renewable energy sources have been designed. The processes were analyzed in the thermodynamic process simulation tool DNA. The syngas used for the catalytic methanol production was produced by gasification of biomass, electrolysis of water, CO2...... different syngas production method, were compared. The plants achieve methanol exergy efficiencies of 59-72%, the best from a configuration incorporating autothermal reforming of biogas and electrolysis of water for syngas production. The different processes in the plants are highly heat integrated, and the...... low-temperature waste heat is used for district heat production. This results in high total energy efficiencies (similar to 90%) for the plants. The specific methanol costs for the six plants are in the range 11.8-25.3 (sic)/GJ(exergy). The lowest cost is obtained by a plant using electrolysis of...

  4. Status of the development of solid polymer electrolyte water electrolysis for large scale hydrogen generation

    Science.gov (United States)

    Russell, J. H.

    1982-02-01

    Solid polymer electrolyte water electrolysis for large scale hydrogen generation is reported. The program was aimed at performance improvement. Reductions in cell impedance were demonstrated which improve cell performance by over 100 mV. A prototype 500 SCFH system for field evaluation was developed.

  5. Hydrogen production by high-temperature electrolysis of water vapor. Experimental results obtained on electrolytic tube

    International Nuclear Information System (INIS)

    The results of experimental studies in the area of high-temperature physics, conducted on a research reactor at the Institute of Atomic Energy in Japan (basic institute) are presented. Problems on production of hydrogen by high-temperature electrolysis of water vapor, relative to HTGR, are considered

  6. Technoeconomic analysis of a methanol plant based on gasification of biomass and electrolysis of water

    International Nuclear Information System (INIS)

    Methanol production process configurations based on renewable energy sources have been designed. The processes were analyzed in the thermodynamic process simulation tool DNA. The syngas used for the catalytic methanol production was produced by gasification of biomass, electrolysis of water, CO2 from post-combustion capture and autothermal reforming of natural gas or biogas. Underground gas storage of hydrogen and oxygen was used in connection with the electrolysis to enable the electrolyser to follow the variations in the power produced by renewables. Six plant configurations, each with a different syngas production method, were compared. The plants achieve methanol exergy efficiencies of 59-72%, the best from a configuration incorporating autothermal reforming of biogas and electrolysis of water for syngas production. The different processes in the plants are highly heat integrated, and the low-temperature waste heat is used for district heat production. This results in high total energy efficiencies (∼90%) for the plants. The specific methanol costs for the six plants are in the range 11.8-25.3 Euro /GJexergy. The lowest cost is obtained by a plant using electrolysis of water, gasification of biomass and autothermal reforming of natural gas for syngas production.

  7. Treatment of process water containing heavy metals with a two-stage electrolysis procedure in a membrane electrolysis cell

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, R.; Krebs, P. [Technische Universitaet Dresden, Institut fuer Siedlungs- und Industriewasserwirtschaft, Mommsenstrasse 13, 01062 Dresden (Germany); Seidel, H. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Department Bioremediation, Permoserstrasse 15, D-04318 Leipzig (Germany); Morgenstern, P. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Department Analytik, Permoserstrasse 15, D-04318 Leipzig (Germany); Foerster, H.J.; Thiele, W. [Eilenburger Elektrolyse- und Umwelttechnik GmbH, Ziegelstrasse 2, D-04838 Eilenburg (Germany)

    2005-04-01

    The capability of a two-stage electrochemical treatment for the regeneration of acidic heavy-metal containing process water was examined. The process water came from sediment bioleaching and was characterized by a wide spectrum of dissolved metals, a high sulfate content, and a pH of about 3. In the modular laboratory model cell used, the anode chamber and the cathode chamber were separated by a central chamber fitted with an ion exchanger membrane on either side. The experiments were carried out applying a platinum anode and a graphite cathode at a current density of 0.1 A/cm{sup 2}. The circulation flow of the process water in the batch process amounted to 35 L/h, the electrolysis duration was 5.5 h at maximum and the total electrolysis current was about 1 A. In the first stage, the acidic process water containing metals passed through the cathode chamber. In the second stage, the cathodically pretreated process water was electrolyzed anodically. In the cathode chamber the main load of dissolved Cu, Zn, Cr and Pb was eliminated. The sulfuric acid surplus of 3-4 g/L decreased to about 1 g/L, the pH rose from initially 3.0 to 4-5, but the desired pH of 9-10 was not achieved. Precipitation in the proximity to the cathode evidently takes place at a higher pH than farther away. The dominant process in the anode chamber was the precipitation of amorphous MnO{sub 2} owing to the oxidation of dissolved Mn(II). The further depletion of the remaining heavy metals in the cathodically pretreated process water by subsequent anodic treatment was nearly exhaustive, more than 99 % of Cd, Cr, Cu, Mn, Ni, Pb, and Zn were removed from the leachate. The high depletion of heavy metals might be due to both the sorption on MnO{sub 2} precipitates and/or basic ferrous sulfate formed anodically, and the migration of metal ions through the cation exchanger membrane via the middle chamber into the cathode chamber. In the anode chamber, the sulfuric acid content increased to 6-7 g/L and the

  8. Heavy water in the context of hydrogen economy. Prospects for cheaper production by water electrolysis

    International Nuclear Information System (INIS)

    Hydrogen is an extremely important material. It is commonly used in many industrial processes. It can also be used as the key medium in 'hydrogen energy philosophy' due to its unique energetic properties (production for storage, gas-line transport). Its heavy isotopes, deuterium (D) and tritium (T), are very important nuclear materials. Deuterium, in the form of heavy water, is an excellent moderator in fission reactors, while both D and T are now seen as fuel components in fusion reactors in the future. Thus, improvements of production processes for hydrogen and its isotopes are always actual. Electrolysis (sometimes in combination with other methods) is often used for heavy water production or re-enrichment or for tritium removal from 'nuclear waters', mostly because of high D/H (T/H, T/D) isotope separation factors, although the electrolysis consumes great amounts of energy (about 4.5 to 5 kWh/m3 H2 in industrial electrolyzers). There were various attempts to improve this process: zero-gap cell geometry, development of new diaphragm materials, development of new electrocatalytic materials for electrodes, using so-called ionic activators etc. We investigated the use of catalytic cathode materials made from hypo-hyper-d-electronic combinations of transition metals as well as in situ activation of electrodes. Many intermetallic combinations were tried. Two types of ionic activators were used: tris-(ethylenediamine)-Co(III)-chloride complex and tris-(trimethylenediamine)-Co(III)-chloride complex. Some significant increases of the separation factors were obtained. Dependence of isotope enrichment on the amount of water that must be electrolysed for was estimated for different values of the separation factor. It was concluded that this a good way to increase the efficiency of the process by achieving an energy saving and an increase of the separation factors simultaneously. The method is discussed in a context that assumes heavy water as a by-product of the hydrogen

  9. Electrochemical Behavior of Ni-Mo Electrocatalyst for Water Electrolysis

    OpenAIRE

    Suilma Marisela Fernández-Valverde; Eduardo Ordoñez-Regil; Gerardo Cabañas-Moreno; Omar Solorza-Feria

    2010-01-01

    Nickel-molybdenum based electrolcatalysts were synthesized in organic media for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media. The structure, morphology, and chemical composition of the catalysts were evaluated by XRD, SEM and AAS. Results revealed nanocristalline powder materials with Ni0.006Mo, Ni0.1Mo, and NiMo compositions. The best performance for HER, was obtained on Ni0.1Mo electrode, whereas NiMo was for the OER. Results suggest that the m...

  10. Development of solid electrolytes for water electrolysis at intermediate temperatures. Task 3 report; Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Linkous, C.A.; Anderson, R.; Kopitzke, R.W.

    1995-12-01

    This project is an attempt to synthesize and fabricate proton exchange membranes for hydrogen production via water electrolysis that can take advantage of the better kinetic and thermodynamic conditions that exist at higher temperatures. Current PEM technology is limited to the 125--150 C range. Based on previous work evaluating thermohydrolytic stability, some 5 families of polymers were chosen as viable candidates: polyether ketones, polyether sulfones, fluorinated polyimides, polybenzimidazoles, and polyphenyl quinoxalines. Several of these have been converted into ionomers via sulfonation and fashioned into membranes for evaluation. In particular, the sulfonated polyetheretherketone, or SPEEK, was tested for water uptake, thermo-conductimetric analysis, and performance as the solid electrolyte material in an electrolysis cell. Results comparable to commercial perfluorocarbon sulfonates were obtained.

  11. Hydrogen production by water electrolysis using tetra-alkyl-ammonium-sulfonic acid ionic liquid electrolytes

    Science.gov (United States)

    Fiegenbaum, Fernanda; Martini, Emilse M.; de Souza, Michèle O.; Becker, Márcia R.; de Souza, Roberto F.

    2013-12-01

    Triethylammonium-propanesulfonic acid tetrafluoroborate (TEA-PS·BF4) is used as an electrolyte in the water electrolysis. The electrolysis of water with this ionic conductor produces high current densities with high efficiencies, even at room temperatures. A system using TEA-PS·BF4 in an electrochemical cell with platinum electrodes has current densities (i) up to 1.77 A cm-2 and efficiencies between 93 and 99% in temperatures ranging from 25 °C to 80 °C. The activation energy observed with TEA-PS·BF4 is ca. 9.3 kJ mol-1, a low value that can be explained by the facilitation of proton transport in the organised aqueous ionic liquid media. The unexpectedly high efficiency of this system is discussed by taking into account the high conductivities associated with the Brönsted and Lewis acidity characteristics associated with these ionic conductive materials.

  12. Effect of an additive on thermal output during electrolysis of heavy water with a palladium cathode

    International Nuclear Information System (INIS)

    A titanium additive to a heavy water-sulfuric acid electrolyte has been found to increase the thermal output during electrolysis with a palladium foil cathode. Eight runs, about 6 h each, over a period of 16 days, gave an average of 1.8 W excess thermal power output compared with a light water control cell. This is about twice the excess obtained in co-deposition experiments. The excess thermal power output ranged from 0.5±0.1 to 2.6±0.1 W, which was an average of about 17% more than the input power. The additive apparently catalyzes heat-producing reactions on the surface of the palladium. After electrolysis, the Pd cathode contained localized surface concentrations of Ag, Ni, Fe, Ti, S, and Pt. (author)

  13. Elemental analysis of palladium electrodes after Pd/Pd light water critical electrolysis

    International Nuclear Information System (INIS)

    Elemental analyses of palladium electrodes were conducted after a new type of light water electrolysis was performed at optimum conditions in a system designed to induce a nuclear reaction. This process is referred to as Pd/Pd light water critical electrolysis. The conjecture that a nuclear transmutation process is occurring in this experiment is easier to test in this system, because it is easy to determine whether the elements detected on the cathode surface are impurities or transmutation products. We assume that the elements detected only on the cathode surface, and nowhere else in the cell as contamination, namely iron, titanium, chromium and so on, must be transmutation products. Furthermore, countless Ohmori-type palladium craters were observed for the first time for this system, and these are evidence that nuclear reactions occurred at the electrode surface. (author)

  14. Improvement of anaerobic digestion of waste-activated sludge by using H₂O₂ oxidation, electrolysis, electro-oxidation and thermo-alkaline pretreatments.

    Science.gov (United States)

    Feki, Emna; Khoufi, Sonia; Loukil, Slim; Sayadi, Sami

    2015-10-01

    Disintegration of municipal waste-activated sludge (WAS) is regarded as a prerequisite of the anaerobic digestion process to reduce sludge volume and improve biogas yield. Pretreatment of WAS using thermo-alkaline (TA), H2O2 oxidation, electrolysis and electro-oxidation (EO) processes were investigated and compared in term of COD solubilization and biogas production. For each pretreatment, the influences of different operational variables were studied in detail. At optimum conditions, EO gave the maximum COD solubilization (28 %). The effects of pretreatments under the optimum conditions on anaerobic digestion were experienced with biochemical methane potential assay. Significant increases in biogas yield up to 78 and 40 % were observed respectively in the EO and TA pretreated samples compared to raw sludge. Results clearly revealed that the application of EO is a significant alternative method for the improvement of WAS anaerobic digestion. PMID:25982985

  15. Feasibility Analysis of Liquefying Oxygen Generated from Water Electrolysis Units on Lunar Surface

    Science.gov (United States)

    Jeng, Frank F.

    2009-01-01

    Concepts for liquefying oxygen (O2) generated from water electrolysis subsystems on the Lunar surface were explored. Concepts for O2 liquefaction units capable of generating 1.38 lb/hr (0.63 kg/hr) liquid oxygen (LOX) were developed. Heat and mass balance calculations for the liquefaction concepts were conducted. Stream properties, duties of radiators, heat exchangers and compressors for the selected concepts were calculated and compared.

  16. Sequential Washing with Electrolyzed Alkaline and Acidic Water Effectively Removes Pathogens from Metal Surfaces.

    Science.gov (United States)

    Nakano, Yuichiro; Akamatsu, Norihiko; Mori, Tsuyoshi; Sano, Kazunori; Satoh, Katsuya; Nagayasu, Takeshi; Miyoshi, Yoshiaki; Sugio, Tomomi; Sakai, Hideyuki; Sakae, Eiji; Ichimiya, Kazuko; Hamada, Masahisa; Nakayama, Takehisa; Fujita, Yuhzo; Yanagihara, Katsunori; Nishida, Noriyuki

    2016-01-01

    Removal of pathogenic organisms from reprocessed surgical instruments is essential to prevent iatrogenic infections. Some bacteria can make persistent biofilms on medical devices. Contamination of non-disposable equipment with prions also represents a serious risk to surgical patients. Efficient disinfection of prions from endoscopes and other instruments such as high-resolution cameras remains problematic because these instruments do not tolerate aggressive chemical or heat treatments. Herein, we develop a new washing system that uses both the alkaline and acidic water produced by electrolysis. Electrolyzed acidic water, containing HCl and HOCl as active substances, has been reported to be an effective disinfectant. A 0.15% NaCl solution was electrolyzed and used immediately to wash bio-contaminated stainless steel model systems with alkaline water (pH 11.9) with sonication, and then with acidic water (pH 2.7) without sonication. Two bacterial species (Staphylococcus aureus and Pseudomonas aeruginosa) and a fungus (Candida albicans) were effectively removed or inactivated by the washing process. In addition, this process effectively removed or inactivated prions from the stainless steel surfaces. This washing system will be potentially useful for the disinfection of clinical devices such as neuroendoscopes because electrolyzed water is gentle to both patients and equipment and is environmentally sound. PMID:27223116

  17. Sequential Washing with Electrolyzed Alkaline and Acidic Water Effectively Removes Pathogens from Metal Surfaces.

    Directory of Open Access Journals (Sweden)

    Yuichiro Nakano

    Full Text Available Removal of pathogenic organisms from reprocessed surgical instruments is essential to prevent iatrogenic infections. Some bacteria can make persistent biofilms on medical devices. Contamination of non-disposable equipment with prions also represents a serious risk to surgical patients. Efficient disinfection of prions from endoscopes and other instruments such as high-resolution cameras remains problematic because these instruments do not tolerate aggressive chemical or heat treatments. Herein, we develop a new washing system that uses both the alkaline and acidic water produced by electrolysis. Electrolyzed acidic water, containing HCl and HOCl as active substances, has been reported to be an effective disinfectant. A 0.15% NaCl solution was electrolyzed and used immediately to wash bio-contaminated stainless steel model systems with alkaline water (pH 11.9 with sonication, and then with acidic water (pH 2.7 without sonication. Two bacterial species (Staphylococcus aureus and Pseudomonas aeruginosa and a fungus (Candida albicans were effectively removed or inactivated by the washing process. In addition, this process effectively removed or inactivated prions from the stainless steel surfaces. This washing system will be potentially useful for the disinfection of clinical devices such as neuroendoscopes because electrolyzed water is gentle to both patients and equipment and is environmentally sound.

  18. Sequential Washing with Electrolyzed Alkaline and Acidic Water Effectively Removes Pathogens from Metal Surfaces

    Science.gov (United States)

    Nakano, Yuichiro; Akamatsu, Norihiko; Mori, Tsuyoshi; Sano, Kazunori; Satoh, Katsuya; Nagayasu, Takeshi; Miyoshi, Yoshiaki; Sugio, Tomomi; Sakai, Hideyuki; Sakae, Eiji; Ichimiya, Kazuko; Hamada, Masahisa; Nakayama, Takehisa; Fujita, Yuhzo; Yanagihara, Katsunori; Nishida, Noriyuki

    2016-01-01

    Removal of pathogenic organisms from reprocessed surgical instruments is essential to prevent iatrogenic infections. Some bacteria can make persistent biofilms on medical devices. Contamination of non-disposable equipment with prions also represents a serious risk to surgical patients. Efficient disinfection of prions from endoscopes and other instruments such as high-resolution cameras remains problematic because these instruments do not tolerate aggressive chemical or heat treatments. Herein, we develop a new washing system that uses both the alkaline and acidic water produced by electrolysis. Electrolyzed acidic water, containing HCl and HOCl as active substances, has been reported to be an effective disinfectant. A 0.15% NaCl solution was electrolyzed and used immediately to wash bio-contaminated stainless steel model systems with alkaline water (pH 11.9) with sonication, and then with acidic water (pH 2.7) without sonication. Two bacterial species (Staphylococcus aureus and Pseudomonas aeruginosa) and a fungus (Candida albicans) were effectively removed or inactivated by the washing process. In addition, this process effectively removed or inactivated prions from the stainless steel surfaces. This washing system will be potentially useful for the disinfection of clinical devices such as neuroendoscopes because electrolyzed water is gentle to both patients and equipment and is environmentally sound. PMID:27223116

  19. Organic Fuel Synthesis from Atmospheric Carbon Dioxide and Hydrogen Produced from Water by Electrolysis

    Institute of Scientific and Technical Information of China (English)

    David JOHNSTON

    2009-01-01

    Synthesis of organic fuels from cain dioxide and hydrogen is analysed, in terms of energy recovery efficiency, and the required energy input for electrolysis of water. This electrical energy is related to the thermal energy required in a power station. A method is described to recover heat from energy-producing reactions in the fuel synthesis process, which can then be used to reduce the electrical energy requirement for electrolysis. By co-locating the fuel synthesis plant with a thermal power station, primary (thermal) energy can be used to produce high temperature steam, with a lower electrical requirement for electrolytic production of hydrogen. This can make more efficient use of the primary energy than a thermodynamic engine. Comparison is made with alternative fuels, in terms of energy budget, sustainability, carbon dioxide emissions, etc. The energy security benefits of advanced fuel synthesis are also identified.

  20. Development of new proton exchange membrane electrolytes for water electrolysis at higher temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Linkous, C.A.; Anderson, H.R. [Florida Solar Energy Center, Cocoa (United States); Kopitzke, R.W.; Nelson, G.L. [Florida Institute of Technology, Melbourne (United States). Dept. of Chemistry

    1998-12-01

    This project is an attempt to synthesize and fabricate proton exchange membranes for hydrogen production via water electrolysis that can take advantage of the better kinetic and thermodynamic conditions that exist at higher temperatures. Current PEM technology is limited to the 125-150{sup o}C range. Based on previous work evaluating thermohydrolytic stability, several families of polymers were chosen as viable candidates: polyether ketones, polyether sulfones, polybenzimidazoles, and polyphenyl quinoxalines. Representatives of each were converted into ionomers via sulfonation and fashioned into membranes for evaluation. In particular, the sulfonated polyetheretherketone, or SPEEK, was examined by thermoconductimetric analysis and performance tested in an electrolysis cell. Results comparable to commercial perfluorocarbon sulfonates were obtained. (author)

  1. Hydrogen from renewable energy - Photovoltaic/water electrolysis as an exemplary approach

    Science.gov (United States)

    Sprafka, R. J.; Tison, R. R.; Escher, W. J. D.

    1984-01-01

    A feasibility study has been conducted for a NASA Kennedy Space Center liquid hydrogen/liquid oxygen production facility using solar cell arrays as the power source for electrolysis. The 100 MW output of the facility would be split into 67.6 and 32 MW portions for electrolysis and liquefaction, respectively. The solar cell array would cover 1.65 sq miles, and would be made up of 249 modular 400-kW arrays. Hydrogen and oxygen are generated at either dispersed or centralized water electrolyzers. The yearly hydrogen output is projected to be 5.76 million lbs, with 8 times that much oxygen; these fuel volumes can support approximately 18 Space Shuttle launches/year.

  2. Advances in the electrolysis of tritiated water for its application to a fusion plasma processing plant

    International Nuclear Information System (INIS)

    The exhaust plasma processing scheme, proposed a few years ago as an alternative to the TSTA plant in operation at Los Alamos (N.M.), USA, required further research on some topics such as a low liquid inventory electrolytic cell and the types of separator or membrane resistant to beta radiation. Moreover, it was suggested that the value of the separation factors among H2, D2, T2 should be checked during the electrolysis by using different cathode materials in an alkaline medium. The results of the experimental work carried out on these topics have shown the feasibility of the process although some improvements are still possible as far as the optimization of the separators and the design of the electrolytic cells are concerned. This paper describes the research carried out in the JRC Ispra (Italy) together with some Institutes which have studied contracts with our Establishment

  3. Studies of water electrolysis in polymeric membrane cells; Estudos de eletrolise aquosa em celulas de membrana polimerica

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira-Silva, M.A.; Linardi, M.; Saliba-Silva, A.M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Celulas a Combustivel e Hidrogenio

    2010-07-01

    Hydrogen represents great opportunity to be a substitute for fossil fuels in the future. Water as a renewable source of hydrogen is of great interest, since it is abundant and can decompose, producing only pure H{sub 2} and O{sub 2}. This decomposition of water can be accomplished by processes such as electrolysis, thermal decomposition and thermochemical cycles. The membrane electrolysis has been proposed as a viable process for hydrogen production using thermal and electrical energy derived from nuclear energy or any renewable source like solar energy. In this work, within the context of optimization of the electrolysis process, it is intended to develop a mathematical model that can simulate and assist in parameterization of the electrolysis performed by polymer membrane electrolytic cell. The experimental process to produce hydrogen via the cell membrane, aims to optimize the amount of gas produced using renewable energy with non-carbogenic causing no harm by producing gases deleterious to the environment. (author)

  4. Water rocket - Electrolysis propulsion and fuel cell power

    International Nuclear Information System (INIS)

    Water Rocket is the collective name for an integrated set of technologies that offer new options for spacecraft propulsion, power, energy storage, and structure. Low pressure water stored on the spacecraft is electrolyzed to generate, separate, and pressurize gaseous hydrogen and oxygen. These gases, stored in lightweight pressure tanks, can be burned to generate thrust or recombined to produce electric power. As a rocket propulsion system, Water Rocket provides the highest feasible chemical specific impulse (-400 seconds). Even higher specific impulse propulsion can be achieved by combining Water Rocket with other advanced propulsion technologies, such as arcjet or electric thrusters. With innovative pressure tank technology, Water Rocket's specific energy[Wh/kg] can exceed that of the best foreseeable batteries by an order of magnitude, and the tanks can often serve as vehicle structural elements. For pulsed power applications, Water Rocket propellants can be used to drive very high power density generators, such as MHD devices or detonation-driven pulse generators. A space vehicle using Water Rocket propulsion can be totally inert and non-hazardous during assembly and launch. These features are particularly important for the timely development and flight qualification of new classes of spacecraft, such as microsats, nanosats, and refuelable spacecraft

  5. Nuclear hydrogen using high temperature electrolysis and light water reactors for peak electricity production

    International Nuclear Information System (INIS)

    In a carbon-dioxide-constrained world, the primary methods to produce electricity (nuclear, solar, wind and fossil fuels with carbon sequestration) have low operating costs and high capital costs. To minimise the cost of electricity, these plants must operate at maximum capacity; however, the electrical outputs do not match changing electricity demands with time. A system to produce intermediate and peak electricity is described that uses light water reactors (LWR) and high temperature electrolysis. At times of low electricity demand the LWR provides steam and electricity to a high temperature steam electrolysis system to produce hydrogen and oxygen that are stored. At times of high electricity demand, the reactor produces electricity for the electrical grid. Additional peak electricity is produced by combining the hydrogen and oxygen by operating the high temperature electrolysis units in reverse as fuel cells or using an oxy-hydrogen steam cycle. The storage and use of hydrogen and oxygen for intermediate and peak power production reduces the capital cost, increases the efficiency of the peak power production systems, and enables nuclear energy to be used to meet daily, weekly and seasonal changes in electrical demand. The economic viability is based on the higher electricity prices paid for peak-load electricity. (authors)

  6. Development of solid electrolytes for water electrolysis at intermediate temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Linkous, C.A.; Kopitzke, R.W. [Florida Solar Energy Center, Cape Canaveral, FL (United States)

    1995-09-01

    If an electrolyzer could operate at higher temperatures, several benefits would accrue. The first is that the thermodynamic electrical energy requirement to drive the reaction would be reduced. Supplying the total enthalpy of reaction at any temperature involves a combination of electrical and thermal energy inputs. Because of the positive entropy associated with water decomposition, the thermal contribution increases as temperature rises, allowing the free energy requirement to decrease. Thus the open circuit voltage, V{sub oc}, for water splitting drops as temperature rises. At room temperature, V{sub oc} for water decomposition is 1.229 V. At 400{degrees}C, voltage requirement has dropped to 1.1 V; at 1000{degrees}C, it is only 0.92 V. Since electricity is a more expensive form of energy on a btu basis, the more energy taken from the thermal surroundings the better. Moreover, this thermal energy content could be solar-derived. While the cost of solar thermal energy varies in the range of $360-900/peak kilowatt, the installed cost of photovoltaic electricity is in the range of $4,000-5,000/peak kilowatt. Thus if one is compelled to erect an array of photovoltaic panels to generate the e.m.f. necessary to split water, substituting as much area with thermal collectors as possible represents a substantial cost savings.

  7. Development of solid electrolytes for water electrolysis at higher temperature

    Energy Technology Data Exchange (ETDEWEB)

    Linkous, C.A. [Florida Solar Energy Center, Cocoa, FL (United States)

    1996-10-01

    This report describes efforts in developing new solid polymer electrolytes that will enable operation of proton exchange membrane electrolyzers at higher temperatures than are currently possible. Several ionomers have been prepared from polyetheretherketone (PEEK), polyethersulfone (PES), and polyphenylquinoxaline (PPQ) by employing various sulfonation procedures. By controlling the extent of sulfonation, a range of proton conductivities could be achieved, whose upper limit actually exceeded that of commercially available perfluoralkyl sulfonates. Thermoconductimetric analysis of samples at various degrees of sulfonation showed an inverse relationship between conductivity and maximum operating temperature. This was attributed to the dual effect of adding sulfonate groups to the polymer: more acid groups produce more protons for increased conductivity, but they also increase water uptake, which mechanically weakens the membrane. This situation was exacerbated by the limited acidity of the aromatic sulfonic acids (pK{sub A} {approx} 2-3). The possibility of using partial fluorination to raise the acid dissociation constant is discussed.

  8. Water electrolysis from the sources of aeolian and photovoltaic energies; Eletrolise da agua a partir de fontes de energia eolica e fotovoltaica

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Ennio Peres da [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Lab. de Hidrogenio

    2006-07-01

    This paper presents an overview on the water electrolysis from aeolic and photovoltaic energies sources, considering the following aspects: hydrogen technology; water electrolysis; water dissociators; 3000 A unipolar dissociators; 4000 A unipolar dissociators; bipolar dissociators; generation systems connected to the network; generation systems disconnected from the network; costs of the hydrogen.

  9. Direct anodic hydrochloric acid and cathodic caustic production during water electrolysis

    Science.gov (United States)

    Lin, Hui-Wen; Cejudo-Marín, Rocío; Jeremiasse, Adriaan W.; Rabaey, Korneel; Yuan, Zhiguo; Pikaar, Ilje

    2016-02-01

    Hydrochloric acid (HCl) and caustic (NaOH) are among the most widely used chemicals by the water industry. Direct anodic electrochemical HCl production by water electrolysis has not been successful as current commercially available electrodes are prone to chlorine formation. This study presents an innovative technology simultaneously generating HCl and NaOH from NaCl using a Mn0.84Mo0.16O2.23 oxygen evolution electrode during water electrolysis. The results showed that protons could be anodically generated at a high Coulombic efficiency (i.e. ≥ 95%) with chlorine formation accounting for 3 ~ 5% of the charge supplied. HCl was anodically produced at moderate strengths at a CE of 65 ± 4% together with a CE of 89 ± 1% for cathodic caustic production. The reduction in CE for HCl generation was caused by proton cross-over from the anode to the middle compartment. Overall, this study showed the potential of simultaneous HCl and NaOH generation from NaCl and represents a major step forward for the water industry towards on-site production of HCl and NaOH. In this study, artificial brine was used as a source of sodium and chloride ions. In theory, artificial brine could be replaced by saline waste streams such as Reverse Osmosis Concentrate (ROC), turning ROC into a valuable resource.

  10. Development status of solid polymer electrolyte water electrolysis for large scale hydrogen generation

    Science.gov (United States)

    Russell, J. H.

    1981-03-01

    Solid polymer water electrolysis technology for large scale hydrogen generation is reviewed. A hydrogen generator module, capable of producing 2000 SCFH, was operated successfully for over 700 hours in the 200 kW system. Test results and further information are presented. Technology development was continued in support of improving both capital cost and conversion efficiency. Progress made in the development of the 10 sq ft active area cell included completion of the initial design, the beginning of fabrication development, and installation of new facilities for cell manufacture.

  11. Comparative thermoeconomic analysis of hydrogen production by water electrolysis and by ethanol steam reforming

    Energy Technology Data Exchange (ETDEWEB)

    Riveros-Godoy, Gustavo; Chavez-Rodriguez, Mauro; Cavaliero, Carla [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Mechanical Engineering School], Email: garg@fem.unicamp.br

    2010-07-01

    Hydrogen is the focus of this work that evaluates in comparative form through thermo economic analysis two hydrogen production processes: water electrolysis and ethanol steam reforming. Even though technical-economical barriers still exist for the development of an economy based on hydrogen, these difficulties are opportunities for the appearance of new business of goods and services, diversification of the energy mix, focus of research activities, development and support to provide sustainability to the new economy. Exergy and rational efficiency concept are used to make a comparison between both processes. (author)

  12. Graphene sheets synthesized by ionic-liquid-assisted electrolysis for application in water purification

    International Nuclear Information System (INIS)

    Highlights: ► Graphene sheets have been successfully synthesized by ionic-liquid-assisted electrolysis. ► Graphene sheets are superior adsorbents for heavy metal removal. ► Graphene sheets are highly efficient for water purification for the developing economies. - Abstract: A facile and green synthesis of graphene sheets by ionic-liquid-assisted electrolysis was investigated in this work. The synthesized graphene sheets have been studied using transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray powder diffraction (XRD), Raman spectroscopy (Raman) and Fourier transform infrared (FTIR) analysis. The obtained graphene was used for the adsorption of Fe2+ whose presence in the drinking water in wide areas of South Asia has been widely known. The result shows that the graphene could absorb Fe2+ with a capacity of 299.3 mg/g which is 6 times higher than that of graphite oxide. The adsorption properties of metal ions on graphene and the effects of various factors on the adsorption capacity were also investigated in detail. The research results suggest a novel material for developing highly efficient water purification materials for the developing economies.

  13. Investigations on degradation of the long-term proton exchange membrane water electrolysis stack

    Science.gov (United States)

    Sun, Shucheng; Shao, Zhigang; Yu, Hongmei; Li, Guangfu; Yi, Baolian

    2014-12-01

    A 9-cell proton exchange membrane (PEM) water electrolysis stack is developed and tested for 7800 h. The average degradation rate of 35.5 μV h-1 per cell is measured. The 4th MEA of the stack is offline investigated and characterized. The electrochemical impedance spectroscopy (EIS) shows that the charge transfer resistance and ionic resistance of the cell both increase. The linear sweep scan (LSV) shows the hydrogen crossover rate of the membrane has slight increase. The electron probe X-ray microanalyze (EPMA) illustrates further that Ca, Cu and Fe elements distribute in the membrane and catalyst layers of the catalyst-coated membranes (CCMs). The cations occupy the ion exchange sites of the Nafion polymer electrolyte in the catalyst layers and membrane, which results in the increase in the anode and the cathode overpotentials. The metallic impurities originate mainly from the feed water and the components of the electrolysis unit. Fortunately, the degradation was reversible and can be almost recovered to the initial performance by using 0.5 M H2SO4. This indicates the performance degradation of the stack running 7800 h is mainly caused by a recoverable contamination.

  14. Preliminary study of synthesis gas production from water electrolysis, using the ELECTROFUEL® concept

    International Nuclear Information System (INIS)

    This paper describes preliminary work on the generation of synthesis gas from water electrolysis using graphite electrodes without the separation of the generated gases. This is an innovative process, that has no similar work been done earlier. Preliminary tests allowed to establish correlations between the applied current to the electrolyser and flow rate and composition of the generated syngas, as well as a characterisation of generated carbon nanoparticles. The obtained syngas can further be used to produce synthetic liquid fuels, for example, methane, methanol or DME (dimethyl ether) in a catalytic reactor, in further stages of a present ongoing project, using the ELECTROFUEL® concept. The main competitive advantage of this project lies in the built-in of an innovative technology product, from RE (renewable energy) power in remote locations, for example, islands, villages in mountains as an alternative for energy storage for mobility constraints. - Highlights: • Generation of synthesis gas from water electrolysis without separation of gases. • Obtained syngas: 7.7% CO; 10.3% O2 and 2.0% CO2. • Syngas can further be used to produce synthetic liquid fuels

  15. Development and Study of Tantalum and Niobium Carbides as Electrocatalyst Supports for the Oxygen Electrode for PEM Water Electrolysis at Elevated Temperatures

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Petrushina, Irina; Prag, Carsten Brorson;

    2013-01-01

    Polymer electrolyte membrane (PEM) water electrolysis is a prospective method of producing hydrogen. We focused on one of its issues – the lack of a suitable support material for the anode electrocatalyst. TaC and NbC were studied as possible electrocatalyst supports for the PEM water electrolysis...... be tested as alternative electrocatalyst supports for the hydrogen evolution reaction...

  16. Recycling Carbon Dioxide into Sustainable Hydrocarbon Fuels: Electrolysis of Carbon Dioxide and Water

    Science.gov (United States)

    Graves, Christopher Ronald

    Great quantities of hydrocarbon fuels will be needed for the foreseeable future, even if electricity based energy carriers begin to partially replace liquid hydrocarbons in the transportation sector. Fossil fuels and biomass are the most common feedstocks for production of hydrocarbon fuels. However, using renewable or nuclear energy, carbon dioxide and water can be recycled into sustainable hydrocarbon fuels in non-biological processes which remove oxygen from CO2 and H2O (the reverse of fuel combustion). Capture of CO2 from the atmosphere would enable a closed-loop carbon-neutral fuel cycle. The purpose of this work was to develop critical components of a system that recycles CO2 into liquid hydrocarbon fuels. The concept is examined at several scales, beginning with a broad scope analysis of large-scale sustainable energy systems and ultimately studying electrolysis of CO 2 and H2O in high temperature solid oxide cells as the heart of the energy conversion, in the form of three experimental studies. The contributions of these studies include discoveries about electrochemistry and materials that could significantly improve the overall energy use and economics of the CO2-to-fuels system. The broad scale study begins by assessing the sustainability and practicality of the various energy carriers that could replace petroleum-derived hydrocarbon fuels, including other hydrocarbons, hydrogen, and storage of electricity on-board vehicles in batteries, ultracapacitors, and flywheels. Any energy carrier can store the energy of any energy source. This sets the context for CO2 recycling -- sustainable energy sources like solar and wind power can be used to provide the most energy-dense, convenient fuels which can be readily used in the existing infrastructure. The many ways to recycle CO2 into hydrocarbons, based on thermolysis, thermochemical loops, electrolysis, and photoelectrolysis of CO2 and/or H 2O, are critically reviewed. A process based on high temperature co-electrolysis

  17. Solar hydrogen by high-temperature electrolysis: Flowsheeting and experimental analysis of a tube-type receiver concept for superheated steam production

    OpenAIRE

    Houaijia, Anis; Breuer, Stefan; Thomey, Dennis; Brosig, Christian; Säck, Jan-Peter; Roeb, Martin; Sattler, Christian

    2014-01-01

    High-temperature electrolysis (HTE) offers the potential of considerably higher efficiency than conventional alkaline electrolysis when producing hydrogen from water by solar energy. The production rate of the alkaline electrolyzer process is limited since the whole energy demand is covered by electricity. By contrast, in HTE part of the energy can be introduced as high temperature heat from concentrated solar power (CSP) leading to a significantly higher process efficiency. In the interna...

  18. Reducing the hydrogen production cost by operating alkaline electrolysis as a discontinuous process in the French market context

    International Nuclear Information System (INIS)

    The possible reduction of the hydrogen production cost when operating alkaline electrolysers in a discontinuous way, in order to benefit from low electricity prices, is investigated. Beside the insights about the electricity market (prices do not correlate the demand; they are related to the supply-and-demand hardness), advances in modelling discontinuous operation are proposed. An optimum production cost is found that induces a profit of 4%, with regard to a plant that would work continuously. Specific attention should be given to related over-costs: additional degradation due to frequent transitions from the minimum electrolyser load to the nominal one, higher maintenance needs, and hydrogen storage costs. Such an operating mode would also greatly benefit from a reduction of the electrolyser prices. However, the state-of-the-art as regards the electrolyser minimum loads and transition time appears satisfactory. (authors)

  19. The influence of Ferric ion contamination on the solid polymer electrolyte water electrolysis performance

    International Nuclear Information System (INIS)

    Highlights: • The cathode possesses higher tolerance for the Fe3+ contamination than the anode. • Fe3+ are mostly reduced to Fe2+ rather than occur underpotential deposition. • Increased electrolysis voltage was mainly attributed to ohmic overpotential. • Voltage lags behind current for minutes in the multi-current-step test. • Poisoned electrolyser is mostly recovered by 0.5 M H2SO4 solution treatment for 13 h. - Abstract: Fe3+ is a sort of common metal ion contaminant for the solid polymer electrolyte (SPE) water electrolyser. In this paper, the effect of Fe3+ on the performance of SPE water electrolyser has been investigated by both in-situ and ex-situ characterizations. The electron probe microanalysis and ultraviolet test results showed that Fe3+ could migrate from the anode to the cathode and mostly be reduced to Fe2+ in the cathode rather than occurred underpotential deposition as described in the previous report. The in-situ dynamic contamination test showed that the anode voltage increased sharply as soon as the Fe3+ was fed into the anode, while the cathode voltage kept constant until the contamination time was over 30 minutes, indicating the higher tolerance of the cathode than the anode for the Fe3+ contamination. The calculation results based on the electrochemistry impedance spectroscopy test results revealed that the striking increase of the electrolysis voltage was mainly attributed to the ohmic overpotential, which was due to the replacement of H+ by Fe3+ in the Nafion resin. Interestingly, the voltage lagged behind the current for several minutes in the multi-current-step test for the contaminated electrolyser, which phenomenon may be used for judging whether the SPE water electrolyser performance degradation is due to the metal ions contamination. Furthermore, recovery strategy has been developed, and it was found that the contaminated electrolyser could be mostly recovered by 0.5 M H2SO4 solution treatment for 13 h

  20. Tritium isotope separation from light and heavy water by bipolar electrolysis

    International Nuclear Information System (INIS)

    A process for separating tritium from light and heavy water is described. Hydrogen is transferred at and through bipolar electrodes at rates H > D > T. In a cell containing several bipolar electrodes placed in series between two terminal electrodes, a flow of hydrogen is established from the terminal anode compartment toward the terminal cathode. An electrolyte feed containing tritium is continuously added to the system and is subsequently transported countercurrent to the hydrogen mass transfer. A cascaded system is established, in which effluent streams enriched and depleted in tritium can be withdrawn. The voltage drop is smaller at any bipolar electrode as compared to the voltage for normal electrolysis. Cell design is compact because isotope separation occurs at bipolar electrodes without evolution of gas. Isotope separation was demonstrated in laboratory cells where a steady-state tritium concentration gradient was attained. This gradient was in agreement with concentrations calculated from a derived mathematical model

  1. Development status of solid polymer electrolyte water electrolysis for manned spacecraft life support systems

    Science.gov (United States)

    Nuttall, L. J.; Titterington, W. A.

    1974-01-01

    Details of the design and system verification test results are presented for a six-man-rated oxygen generation system. The system configuration incorporates components and instrumentation for computer-controlled operation with automatic start-up/shutdown sequencing, fault detection and isolation, and with self-contained sensors and controls for automatic safe emergency shutdown. All fluid and electrical components, sensors, and electronic controls are designed to be easily maintainable under zero-gravity conditions. On-board component spares are utilized in the system concept to sustain long-term operation (six months minimum) in a manned spacecraft application. The system is centered on a 27-cell solid polymer electrolyte water electrolysis module which, combined with the associated system components and controls, forms a total system envelope 40 in. high, 40 in. wide, and 30 in. deep.

  2. Physico-Chemical, Biological and Therapeutic Characteristics of Electrolyzed Reduced Alkaline Water (ERAW

    Directory of Open Access Journals (Sweden)

    Marc Henry

    2013-12-01

    Full Text Available The consumption of alkaline reduced water produced by domestic electrolysis devices was approved in Japan in 1965 by the Ministry of Health, Labour and Welfare for the cure of gastro-intestinal disorders. Today, these devices are freely available in several countries and can be easily purchased without reserve. The commercial information included with the device recommends the consumption of 1–1.5 L of water per day, not only for gastro-intestinal disorders but also for numerous other illnesses such as diabetes, cancer, inflammation, etc. Academic research in Japan on this subject has been undergoing since 1990 only but has established that the active ingredient is dissolved dihydrogen that eliminates the free radical HO• in vivo. In addition, it was demonstrated that degradation of the electrodes during functioning of the device releases very reactive nanoparticles of platinum, the toxicity of which has not yet been clearly proven. This report recommends alerting health authorities of the uncontrolled availability of these devices used as health products, but which generate drug substances and should therefore be sold according to regulatory requirements.

  3. Operation of a steady-state pH-differential water electrolysis cell

    Science.gov (United States)

    Teschke, O.; Zwanziger, M. G.

    The design features and experimental results with a steady-state electrolysis cell using an acid pH at the cathode and a basic condition at the anode are described. The differential pH concentrations were configured to obtain water decomposition voltages lower than the nominal 1.23 V at 1 atm and 25 C. Oxygen evolution occurs 0.8 V less anodic at a pH of 14 than at a pH of 0, while lower voltage is needed for hydrogen evolution in an acidic solution. The pH differential was set up with an external water feed in the test cell. The anode and cathode were positioned on either side of a solid polymer electrolyte sheet. The trials were run with pure water in circulating, closed systems, with KOH in a closed system, and with KOH in a circulating system. Lowered electricity consumption was demonstrated, although none of the configurations showed a favorable energy balance.

  4. Radiation-Grafted Polymer Electrolyte Membranes for Water Electrolysis Cells: Evaluation of Key Membrane Properties.

    Science.gov (United States)

    Albert, Albert; Barnett, Alejandro O; Thomassen, Magnus S; Schmidt, Thomas J; Gubler, Lorenz

    2015-10-14

    Radiation-grafted membranes can be considered an alternative to perfluorosulfonic acid (PFSA) membranes, such as Nafion, in a solid polymer electrolyte electrolyzer. Styrene, acrylonitrile, and 1,3-diisopropenylbenzene monomers are cografted into preirradiated 50 μm ethylene tetrafluoroethylene (ETFE) base film, followed by sulfonation to introduce proton exchange sites to the obtained grafted films. The incorporation of grafts throughout the thickness is demonstrated by scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) analysis of the membrane cross-sections. The membranes are analyzed in terms of grafting kinetics, ion-exchange capacity (IEC), and water uptake. The key properties of radiation-grafted membranes and Nafion, such as gas crossover, area resistance, and mechanical properties, are evaluated and compared. The plot of hydrogen crossover versus area resistance of the membranes results in a property map that indicates the target areas for membrane development for electrolyzer applications. Tensile tests are performed to assess the mechanical properties of the membranes. Finally, these three properties are combined to establish a figure of merit, which indicates that radiation-grafted membranes obtained in the present study are promising candidates with properties superior to those of Nafion membranes. A water electrolysis cell test is performed as proof of principle, including a comparison to a commercial membrane electrode assembly (MEA). PMID:26393461

  5. Destruction of 4-phenolsulfonic acid in water by anodic contact glow discharge electrolysis

    Institute of Scientific and Technical Information of China (English)

    Haiming Yang; Baigang An; Shaoyan Wang; Lixiang Li; Wenjie Jin; Lihua Li

    2013-01-01

    Destruction of 4-phenolsulfonic acid (4-PSA) in water was carried out using anodic contact glow discharge electrolysis.Accompanying the decay of 4-PSA,the amount of total organic carbon (TOC) in water correspondingly decreased,while the sulfonate group of 4-PSA was released as sulfate ion.Oxalate and formate were obtained as minor by-products.Additionally,phenol,1,4-hydroquinone,hydroxyquinol and 1,4-benzoquinone were detected as primary intermediates in the initial stages of decomposition of 4-PSA.A reaction pathway involving successive attacks of hydroxyl and hydrogen radicals was assumed on the basis of the observed products and kinetics.It was revealed that the decay of both 4-PSA and TOC obeyed a first-order rate law.The effects of different Fe ions and initial concentrations of 4-PSA on the degradation rate were investigated.It was found that the presence of Fe ions could increase the degradation rate of 4-PSA,while initial concentrations lower than 80 mmol/L had no significant effect on kinetic behaviour.The disappearance rate of 4-PSA was significantly affected by pH.

  6. High-Performance Water Electrolysis System with Double Nanostructured Superaerophobic Electrodes.

    Science.gov (United States)

    Xu, Wenwen; Lu, Zhiyi; Wan, Pengbo; Kuang, Yun; Sun, Xiaoming

    2016-05-01

    Catalysts screening and structural optimization are both essential for pursuing a high-efficient water electrolysis system (WES) with reduced energy supply. This study demonstrates an advanced WES with double superaerophobic electrodes, which are achieved by constructing a nanostructured NiMo alloy and NiFe layered double hydroxide (NiFe-LDH) films for hydrogen evolution and oxygen evolution reactions, respectively. The superaerophobic property gives rise to significantly reduced adhesion forces to gas bubbles and thereby accelerates the hydrogen and oxygen bubble releasing behaviors. Benefited from these metrics and the high intrinsic activities of catalysts, this WES affords an early onset potential (≈1.5 V) for water splitting and ultrafast catalytic current density increase (≈0.83 mA mV(-1) ), resulting in ≈2.69 times higher performance compared to the commercial Pt/C and IrO2 /C catalysts based counterpart under 1.9 V. Moreover, enhanced performance at high temperature as well as prominent stability further demonstrate the practical application of this WES. PMID:26997618

  7. Enhanced hematite water electrolysis using a 3D antimony-doped tin oxide electrode.

    Science.gov (United States)

    Moir, Jonathon; Soheilnia, Navid; O'Brien, Paul; Jelle, Abdinoor; Grozea, Claudia M; Faulkner, Daniel; Helander, Michael G; Ozin, Geoffrey A

    2013-05-28

    We present herein an example of nanocrystalline antimony-doped tin oxide (nc-ATO) disordered macroporous "inverse opal" 3D electrodes as efficient charge-collecting support structures for the electrolysis of water using a hematite surface catalyst. The 3D macroporous structures were created via templating of polystyrene spheres, followed by infiltration of the desired precursor solution and annealing at high temperature. Using cyclic voltammetry and electrochemical impedance spectroscopy, it was determined that the use of this 3D transparent conducting oxide with a hematite surface catalyst allowed for a 7-fold increase in active surface area for water splitting with respect to its 2D planar counterpart. This ratio of surface areas was evaluated based on the presence of oxidized trap states on the hematite surface, as determined from the equivalent circuit analysis of the Nyquist plots. Furthermore, the presence of nc-ATO 2D and 3D "underlayer" structures with hematite deposited on top resulted in decreased charge transfer resistances and an increase in the number of available active surface sites at the semiconductor-liquid junction when compared to hematite films lacking any nc-ATO substructures. Finally, absorption, transmission, and reflectance spectra of all of the tested films were measured, suggesting the feasibility of using 3D disordered structures in photoelectrochemical reactions, due to the high absorption of photons by the surface catalyst material and trapping of light within the structure. PMID:23581965

  8. Pre-investigation of water electrolysis for flexible energy storage at large scales: the case of the Spanish power system

    OpenAIRE

    Gutierrez Martin, Fernando; Ochoa Mendoza, Almudena; Rodriguez Anton, Luis Miguel

    2015-01-01

    This report analyzes the basis of hydrogen and power integration strategies, by using water electrolysis processes as a means of flexible energy storage at large scales. It is a prospective study, where the scope is to describe the characteristics of current power systems (like the generation technologies, load curves and grid constraints), and define future scenarios of hydrogen for balancing the electrical grids, considering the efficiency, economy and easiness of operations. We focus in th...

  9. Highly efficient high temperature electrolysis

    DEFF Research Database (Denmark)

    Hauch, Anne; Ebbesen, Sune; Jensen, Søren Højgaard;

    2008-01-01

    High temperature electrolysis of water and steam may provide an efficient, cost effective and environmentally friendly production of H-2 Using electricity produced from sustainable, non-fossil energy sources. To achieve cost competitive electrolysis cells that are both high performing i.e. minimum...... internal resistance of the cell, and long-term stable, it is critical to develop electrode materials that are optimal for steam electrolysis. In this article electrolysis cells for electrolysis of water or steam at temperatures above 200 degrees C for production of H-2 are reviewed. High temperature...... electrolysis is favourable from a thermodynamic point of view, because a part of the required energy can be supplied as thermal heat, and the activation barrier is lowered increasing the H-2 production rate. Only two types of cells operating at high temperature (above 200 degrees C) have been described in the...

  10. High Temperature Water Electrolysis Using Metal Supported Solid Oxide Electrolyzer Cells (SOEC)

    OpenAIRE

    Schiller, Günter; Ansar, Asif Syed; Patz, Olaf

    2010-01-01

    Metal supported cells as developed at DLR for use as solid oxide fuel cells by applying plasma deposition technologies were investigated in operation of high temperature steam electrolysis. The cells consisted of a porous ferritic steel support, a diffusion barrier layer, a Ni/YSZ fuel electrode, a YSZ electrolyte and a LSCF oxygen electrode. During fuel cell and electrolysis operation the cells were electrochemically characterized by means of i-V characteristics and electrochemical impedance...

  11. An analysis of degradation phenomena in polymer electrolyte membrane water electrolysis

    Science.gov (United States)

    Rakousky, Christoph; Reimer, Uwe; Wippermann, Klaus; Carmo, Marcelo; Lueke, Wiebke; Stolten, Detlef

    2016-09-01

    The durability of a polymer electrolyte membrane (PEM) water electrolysis single cell, assembled with regular porous transport layers (PTLs) is investigated for just over 1000 h. We observe a significant degradation rate of 194 μV h-1 and conclude that 78% of the detectable degradation can be explained by an increase in ohmic resistance, arising from the anodic Ti-PTL. Analysis of the polarization curves also indicates a decrease in the anodic exchange current density, j0, that results from the over-time contamination of the anode with Ti species. Furthermore, the average Pt-cathode particle size increases during the test, but we do not believe this phenomenon makes a significant contribution to increased cell voltages. To validate the anode Ti-PTL as a crucial source of increasing resistance, a second cell is assembled using Pt-coated Ti-PTLs. This yields a substantially reduced degradation rate of only 12 μV h-1, indicating that a non-corroding anode PTL is vital for PEM electrolyzers. It is our hope that forthcoming tailored PTLs will not only contribute to fast progress on cost-efficient stacks, but also to its long-term application of PEM electrolyzers involved in industrial processes.

  12. SISGR-Fundamental Experimental and Theoretical Studies on a Novel Family of Oxide Catalyst Supports for Water Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Kumta, Prashant [University of Pittsburgh

    2014-10-03

    Identification and development of non-noble metal based electro-catalysts or electro-catalysts with significant reduction of expensive noble metal contents (E.g. IrO2, Pt) with comparable electrochemical performance as the standard noble metal/metal oxide for proton exchange membrane (PEM) based water electrolysis would constitute a major breakthrough in the generation of hydrogen by water electrolysis. Accomplishing such a system would not only result reduction of the overall capital costs of PEM based water electrolyzers, but also help attain the targeted hydrogen production cost [< $ 3.0 / gallon gasoline equivalent (gge)] comparable to conventional liquid fuels. In line with these goals, it was demonstrated that fluorine doped IrO2 thin films and nanostructured high surface area powders display remarkably higher electrochemical activity, and comparable durability as pure IrO2 electro-catalyst for the oxygen evolution reaction (OER) in PEM based water electrolysis. Furthermore, corrosion resistant SnO2 and NbO2 support has been doped with F and coupled with IrO2 or RuO2 for use as an OER electro-catalyst. A solid solution of SnO2:F or NbO2:F with only 20 - 30 mol.% IrO2 or RuO2 yielding a rutile structure in the form of thin films and bulk nanoparticles displays similar electrochemical activity and stability as pure IrO2/RuO2. This would lead to more than 70 mol.% reduction in the noble metal oxide content. Novel nanostructured ternary (Ir,Sn,Nb)O2 thin films of different compositions FUNDAMENTAL STUDY OF NANOSTRUCTURED ELECTRO-CATALYSTS WITH REDUCED NOBLE METAL CONTENT FOR PEM BASED WATER ELECTROLYSIS 4 have also been studied. It has been shown that (Ir0.40Sn0.30Nb0.30)O2 shows similar electrochemical activity and enhanced chemical robustness as compared to pure IrO2. F doping of the ternary (Ir,Sn,Nb)O2 catalyst helps in further decreasing the noble metal oxide content of the catalyst. As a result, these reduced noble metal oxide catalyst systems would

  13. Electrolysis of ammonia for hydrogen production catalyzed by Pt and Pt-Ir deposited on nickel foam

    Institute of Scientific and Technical Information of China (English)

    Min; Jiang; Dandan; Zhu; Xuebo; Zhao

    2014-01-01

    Electrolysis of ammonia in alkaline electrolyte solution was applied for the production of hydrogen. Both Pt-loaded Ni foam and Pt-Ir loaded Ni foam electrodes were prepared by electrodeposition and served as anode and cathode in ammonia electrolytic cell, respectively. The electrochemical behaviors of ammonia in KOH solution were individually investigated via cyclic voltammetry on three electrodes, i.e. bare Ni foam electrode, Pt-loaded Ni foam electrode and Pt-Ir loaded Ni foam electrode. The morphology and composition of the prepared Ni foam electrode were analyzed by scanning electron microscopy(SEM) and X-ray diffraction(XRD). Effects of the concentration of electrolyte solution and temperature of electrolytic cell on the electrolysis reaction were examined in order to enhance the efficiency of ammonia electrolysis. The competition of ammonia electrolysis and water electrolysis in the same alkaline solution was firstly proposed to explain the changes of cell voltage with the electrolysis proceeding. At varying current densities, different cell voltages could be obtained from galvanostatic curves.The low cell voltage of 0.58 V, which is less than the practical electrolysis voltage of water(1.6 V), can be obtained at a current density of2.5 mA/cm2. Based on some experimental parameters, such as the applied current, the resulting cell voltage and output of hydrogen gas, the power consumption per gram of H2produced can be estimated.

  14. Hydrogen production through small capacity water electrolysis systems; Production d'hydrogene par electrolyse de l'eau. Application a des systemes de petite capacite

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Ph. [TotalFinaElf, la Defense 6, 92 - Courbevoie (France)

    2002-01-01

    Less than 1 % of the world's hydrogen is produced by electrolysis of water, in large plants mainly in connection with hydropower. For users requiring extremely pure hydrogen, electrolysis can be a convenient mean of obtaining the required hydrogen quality, where cheap electricity is available. This paper aims at presenting the latest technical developments of small capacity electrolyzers, that could fuel hydrogen cells or internal combustion engines. (author)

  15. Techno-economic study of hydrogen production by high temperature electrolysis coupled with an EPR-water steam production and coupling possibilities

    International Nuclear Information System (INIS)

    Nuclear reactors present a wide range of coupling possibilities with several industrial processes, hydrogen production being one of them. Among the Pressurised Water nuclear Reactors (PWR), the new European Pressurised Reactor (EPR) offers the water steam production at low-medium temperatures, from 230 degree Celsius to 330 degree Celsius for the primary and secondary exchange circuits. The use of this water steam for hydrogen production by High Temperature Electrolysis is the subject of this study, under a French context. The study of this coupling, has considered two hypotheses. First, water steam drawing off in secondary circuit has been evaluated in terms of possible impact in electricity production and reactor availability. After the drawing off at 78 bar (EPR secondary circuit pressure), pressure has to be dropped in order to protect the high temperature electrolyser from damage, so an isenthalpic drop has been considered. Liquid-vapour equilibrium happens with pressure drops, so separation of gas phase and recycling of liquid phase are proposed. Second, only water steam production with an EPR has been evaluated. The feed water enters the secondary circuit and passes from liquid phase to vapour in the steam generators, and then all steam is canalized to the high temperature electrolyser. The potentiality of water steam production in the EPR has been evaluated from 15 to 40 bar. Small reactors could be the best choice if only water steam production is considered. After steam production, it steam enters into the High Temperature Electrolysis process, like a cold stream for two parallel series of three heat exchangers reaching temperatures up to 950 degree Celsius. Then the steam is heated by an electric device and finally it enters the electrolyser. The electrolysis product streams (hydrogen-steam mixture and oxygen) are used in the heat exchangers like hot streams. For both hypotheses, information about water composition has been studied in order to minimise

  16. Development of new electrode materials for hydrogen production by water electrolysis

    International Nuclear Information System (INIS)

    It is expected that PEM water electrolysis will play a significant role in the hydrogen society as a key process for producing hydrogen from renewable energy sources but before this, substantial cost reductions are still required. Because of the high acidity of membrane materials used in PEM water electrolysers, expensive noble-metals or their oxides are required as electrocatalysts (platinum for hydrogen evolution and iridium for oxygen evolution). As the oxygen evolution reaction takes place with a large overpotential (anodic potential ≥ 1.6 V) only few materials can be used to avoid corrosion. In state-of-the-art, noble metal oxides are generally used alone in the active layer with typical loadings of 2-3 mg/cm2 and act as both catalyst and electronic conductor.In order to reduce the noble metal loadings and keep a good electronic conductivity of the catalytic layer, iridium can be supported onto a conductive and electrochemical stable material support. To gain more insights, several MEAs with anodes made of pure iridium oxide or 50 wt % IrO2/Ti anodes have been prepared and characterized using cyclic voltammetry and impedance spectroscopy, and by measuring polarization curves at different operating temperatures. Without the catalyst support, anodic loadings can be reduced down to 0,5 mg/cm2 without any degradation in the electrochemical performances. By using anodes made of iridium oxide and titanium particles, further reductions of anodic loading can be made down to 0.1 mg/cm2 with performances similar to those obtained with conventional loadings of several mg cm2. (author)

  17. The stability of hydrogen evolution activity and corrosion behavior of NiCu coatings with long-term electrolysis in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Solmaz, Ramazan; Doener, Ali; Kardas, Guelfeza [Cukurova University, Science and Letters Faculty, Chemistry Department, 01330, Balcali, Adana (Turkey)

    2009-03-15

    In this study, NiCu composite coating was electrochemically deposited on a copper electrode (Cu/NiCu) and tested for hydrogen evolution reaction (HER) in 1 M KOH solution for long-term electrolysis with the help of cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. The bulk and surface composition of the coating was determined using atomic absorption spectroscopy (AAS) and energy dispersive X-ray (EDX) analysis. The surface morphology was investigated by scanning electron microscopy (SEM). The effect of electrolysis on the corrosion behavior of the Cu/NiCu electrode was also reported. It was found that the NiCu coating had a compact and porous structure with good time stability. The HER activity of the coating was stable over 120 h electrolysis and the HER mechanism was not modified during the operation. The corrosion tests showed that the corrosion resistance of the Cu/NiCu electrode changed when a cathodic current was applied to the electrolysis system. (author)

  18. Life cycle assessment of high temperature electrolysis for hydrogen production via nuclear energy

    International Nuclear Information System (INIS)

    A life cycle assessment (LCA) of one proposed method of hydrogen production - the high temperature electrolysis of water vapor - is presented in this paper. High temperature electrolysis offers an advantage of higher energy efficiency over the conventional low-temperature alkaline electrolysis due to reduced cell potential and consequent electrical energy requirements. The primary energy source for the electrolysis will be advanced nuclear reactors operating at temperatures corresponding to those required for the high temperature electrolysis. The LCA examines the environmental impact of the combined advanced nuclear-high temperature electrolysis plant, focusing upon quantifying the emissions of carbon dioxide, sulfur dioxide, and nitrogen oxides per kilogram of hydrogen produced. The results are presented in terms of the global warming potential (GWP) and the acidification potential (AP) of the system. The GWP for the system is 2000g carbon dioxide equivalent and the AP, 0.15g equivalents of hydrogen ion equivalent per kilogram of hydrogen produced. The GWP and AP of this process are one-sixth and one-third, respectively, of those for the hydrogen production by steam reforming of natural gas, and are comparable to producing hydrogen from wind- or hydro-electricity powered conventional electrolysis. (author)

  19. A study on water treatment induced by plasma with contact glow discharge electrolysis

    International Nuclear Information System (INIS)

    Oxidative degradation of eight kinds of dyes induced by plasma in aqueous solution was investigated with contract glow discharge electrolysis (CGDE). It has been demonstrated that these eight dyes underwent degradation in CGDE, where Fe2+ could be utilised to raise the efficiency of degradation of dyes

  20. Nanoporous materials for reducing the over potential of creating hydrogen by water electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Marc A.; Leonard, Kevin C.

    2016-06-14

    Disclosed is an electrolyzer including an electrode including a nanoporous oxide-coated conducting material. Also disclosed is a method of producing a gas through electrolysis by contacting an aqueous solution with an electrode connected to an electrical power source, wherein the electrode includes a nanoporous oxide-coated conducting material.

  1. Effect of Strongly Alkaline Electrolyzed Water on Silk Degumming and the Physical Properties of the Fibroin Fiber.

    Directory of Open Access Journals (Sweden)

    Ting-Ting Cao

    Full Text Available Strongly alkaline electrolyzed water (SAEW was prepared by electrolysis of tap water in a laboratory-made water electrolyzer. The pH of stored SAEW was stable for more than one month. The hardness of the electrolyzed water was 30% lower and the Na(+ concentration was 18% higher than those of the tap water. Silkworm cocoon shells were boiled in pH 11.50 SAEW at a ratio of 1∶40∼80 (W/V for 20 min and the sericin layers around the silk fibroin fibers were removed completely. The tensile properties and thermal decomposition temperature of a single filament of silk fibroin obtained by the SAEW method were almost the same as those for the fiber obtained by the neutral soap, and much higher than those for the fiber obtained by Na2CO3 degumming. The results demonstrate that SAEW is an environmentally friendly and pollution-free silk degumming agent that allows highly efficient, low cost recovery of sericin.

  2. Fundamental study of nanostructured electro-catalysts with reduced noble metal content for PEM based water electrolysis

    Science.gov (United States)

    Kadakia, Sandeep Karan

    Identification and development of non-noble metal based electro-catalysts or electro-catalysts with significant reduction of expensive noble metal contents (E.g. IrO2, Pt) with comparable electrochemical performance as the standard noble metal/metal oxide for proton exchange membrane (PEM) based water electrolysis would constitute a major breakthrough in the generation of hydrogen by water electrolysis. Accomplishing such a system would not only result reduction of the overall capital costs of PEM based water electrolyzers, but also help attain the targeted hydrogen production cost [oxygen evolution reaction (OER) in PEM based water electrolysis. Furthermore, corrosion resistant SnO2 and NbO 2 support has been doped with F and coupled with IrO2 or RuO2 for use as an OER electro-catalyst. A solid solution of SnO 2:F or NbO2:F with only 20 - 30 mol.% IrO2 or RuO2 yielding a rutile structure in the form of thin films and bulk nanoparticles displays similar electrochemical activity and stability as pure IrO2/RuO2. This would lead to more than 70 mol.% reduction in the noble metal oxide content. Novel nanostructured ternary (Ir,Sn,Nb)O 2 thin films of different compositions have also been studied. It has been shown that (Ir0.40Sn0.30Nb 0.30)O2 shows similar electrochemical activity and enhanced chemical robustness as compared to pure IrO2. F doping of the ternary (Ir,Sn,Nb)O2 catalyst helps in further decreasing the noble metal oxide content of the catalyst. As a result, these reduced noble metal oxide catalyst systems would potentially be preferred as OER electro-catalysts for PEM electrolysis. The excellent performance of the catalysts coupled with its robustness would make them great candidates for contributing to significant reduction in the overall capital costs of PEM based water electrolyzers. This thesis provides a detailed fundamental study of the synthesis, materials, characterization, theoretical studies and detailed electrochemical response and potential

  3. Perspectives de développement de la production industrielle d'hydrogène par électrolyse alcaline avancée Development Outlook for Industrial Hydrogen Production by Advanced Alkaline Electrolysis

    Directory of Open Access Journals (Sweden)

    Derive C.

    2006-11-01

    -prototypes sont prolongés et deux programmes complémentaires d'essais sur les composants principaux sont actuellement menés avant l'engagement de la phase de qualification de l'électrolyseur industriel sur un pilote de 2 MWe. Under the development conditions of the French nuclear program, which has succeeded in producing electricity at an interesting cost in off-peak hours, hydrogen production by water electrolysis can be considered in the mediumterm to be in competition with other hydrogen production processes such as natural-gas reforming. Since 1976 Electricité de France (EDF and Gaz de France (GDF have been cooperating on an R & D project on hydrogen production by alkaline water electrolysis with the aim of reducing the investment cost and maintaining the efficiency level compared to present-day installations. Prior research has shown that these objectives can be attained by advanced electrolysis with increased current density and temperature. These technical constraints have led EDF and GDF to undertake research on the chemical and mechanical resistance of materials, on the selection of suitable cell components, and on improving the overall design of installations. The two French industrial groups, headed by Alsthom-Atlantique and Creusot-Loire, have been associated to this research since 1979 and have set the following operating conditions:(a potash-base electrolyte (40% mass;(b temperatures of 120 and 160°C;(c pressures of 30 and 70 bar. In an initial phase, these groups made a technico-economic survey of the massive production of hydrogen by plants having a power of about 300 MWe. Detailed plans were drawn up for a 2-MWe pilot plant, and technological choices were made on 25-30 kWe prototype loops. To give further certainty to the choices made and to go further into problems of scaling up to large-size electrolyzers, tests on prototype loops were extended, and additional tests are now being made of the principal components before undertaking the qualification phase

  4. Comparative studies on performance of radiation-induced and thermal cross-linked ion-exchange membrane for water electrolysis

    International Nuclear Information System (INIS)

    Radiation-induced and thermal cross-linked sulfonated poly(ether sulfone) (SPS)-sulfonated poly(ether ether ketone) (SPK) composite ion-exchange membranes (SPS/SPK(γ) and SPS/SPK(T), respectively) were prepared. Their performances for water electrolysis were comparatively assessed. Thermal cross-linked membrane (SPS/SPK(T)) showed cross-linking of part functional groups (-SO3H) and thus deterioration in membrane conductivity. While, radiation-induced cross-linked membrane (SPS/SPK(γ)) avoided any cross-linking between functional groups and thus conductivity. Electrolysis performances of these membranes were evaluated in comparison with Nafion117 membrane. Relatively low current efficiency (CE) for SPS/SPK and SPS/SPK(T) membranes was due to their high mass transfer (water) via electro-osmotic drag, which was negligible for SPS/SPK(γ) membrane. SPS/SPK(γ) membrane exhibited comparable stabilities and water splitting performance with Nafion117 membrane, which revealed its suitability as substitute for electrochemical applications.

  5. High Temperature Water Electrolysis Using Metal Supported Solid Oxide Electrolyser Cells (SOEC)

    OpenAIRE

    Schiller, Günter; Ansar, Asif; Lang, Michael; Patz, Olaf

    2009-01-01

    Metal supported cells as developed according to the DLR SOFC concept by applying plasma deposition technologies were investigated for use as solid oxide electrolyser cells (SOEC) for high temperature steam electrolysis. Cells consisting of a porous ferritic steel support, a diffusion barrier layer, a Ni/YSZ hydrogen electrode, a YSZ electrolyte and a LSCF oxygen electrode were electrochemically characterised by means of i-V characteristics and electrochemical impedance spectroscopy measuremen...

  6. Influence from sea water constituents on the efficiency of water electrolysis by PEM-cells

    DEFF Research Database (Denmark)

    Agersted, Karsten; Bentzen, Janet Jonna; Yde-Andersen, S.

    Among the sea-water specific impurities tested, magnesium has the most profound effect on PEM-cell degradation. Significant amounts of the cation was retrieved in the NAFION®-membrane structure after testing. Degradation was seen from a magnesium concentration as low as 3 10-7 mol/l, and increasing...... necessary to purify the feed water to ~1 μS/cm or even further while particularly focusing on the concentrations of polyvalent cations. e.g. magnesium....

  7. Microbial Challenge Testing of Single Liquid Cathode Feed Water Electrolysis Cells for the International Space Station (ISS) Oxygen Generator Assembly (OGA)

    Science.gov (United States)

    Roy, Robert J.; Wilson, Mark E.; Diderich, Greg S.; Steele, John W.

    2011-01-01

    The International Space Station (ISS) Oxygen Generator Assembly (OGA) operational performance may be adversely impacted by microbiological growth and biofilm formation over the electrolysis cell membranes. Biofilms could hinder the transport of water from the bulk fluid stream to the membranes and increase the cell concentration overpotential resulting in higher cell voltages and a shorter cell life. A microbial challenge test was performed on duplicate single liquid-cathode feed water electrolysis cells to evaluate operational performance with increasing levels of a mixture of five bacteria isolated from ISS and Space Shuttle potable water systems. Baseline performance of the single water electrolysis cells was determined for approximately one month with deionized water. Monthly performance was also determined following each inoculation of the feed tank with 100, 1000, 10,000 and 100,000 cells/ml of the mixed suspension of test bacteria. Water samples from the feed tank and recirculating water loops for each cell were periodically analyzed for enumeration and speciation of bacteria and total organic carbon. While initially a concern, this test program has demonstrated that the performance of the electrolysis cell is not adversely impacted by feed water containing the five species of bacteria tested at a concentration measured as high as 1,000,000 colony forming units (CFU)/ml. This paper presents the methodologies used in the conduct of this test program along with the performance test results at each level of bacteria concentration.

  8. ALKALINE PEROXIDE BLEACHING OF HOT WATER TREATED WHEAT STRAW

    Directory of Open Access Journals (Sweden)

    Suvi Mustajoki

    2010-05-01

    Full Text Available The aim of this study was to evaluate the possibilities for chemical consumption reduction in P-P-Paa-P bleaching (P alkaline peroxide stage, Paa peracetic stage of hot water treated straw and the effect of the wheat straw variability on the process. Papermaking fibre production from wheat straw using such a process could be implemented on a small scale if chemical consumption was low enough to eliminate the need for chemical recovery. The pulp properties obtained with this process are equal to or even superior to the properties of wheat straw soda pulp. The possibility of enhancing the first peroxide stage with oxygen and pressure was studied. The possibility for substitution of sodium hydroxide partially with sodium carbonate was also investigated. The objective was to achieve International Standardization Organization (ISO brightness of 75%, with minimal sodium hydroxide consumption, whilst maintaining the pulp properties. The optimization of the peroxide bleaching is challenging if the final brightness target cannot be reduced. Results indicate that up to 25% of the sodium hydroxide could be substituted with sodium carbonate without losing brightness or affecting pulp properties. Another possibility is a mild alkali treatment between the hot water treatment and the bleaching sequence.

  9. A Study of Gas Diffusion Electrodes for the Coupled Reaction of Water Electrolysis and Electrocatalytic Benzene Hydrogenation

    Institute of Scientific and Technical Information of China (English)

    HuangHaiyan; YuYing; WangJing

    2005-01-01

    Gas diffusion electrodes are applied to the coupled reaction of water electrolysis and electrocatalytic benzene hydrogenation. The effects of the preparation conditions of electrodes, electrolyte acidity, the concentration of benzene and water vapor, and the flow rate of N2 are investigated by evaluating the efficiency of the current. Furthermore, the optimal operational conditions have been ascertained. The results of our experiment show that gas diffusion electrodes have good performance when the content of PTFE is 10% (wt) and that of Nation is 0.75mg/cm2. The optimal operational conditions are as follows: The temperature of electrolysis is 70℃, acidity 0.5tool/L, the concentration of benzene 26%,the concentration of vapor 10%, the flow rate of N2 80mL/min-240mL/min. The efficiency of the current can reach 35% under optimal operational conditions. Then, a conclusion can be drawn that gas diffusion electrodes can improve the rate of the coupled reaction effectively.

  10. Decreasing operating potential for water electrolysis to hydrogen via local confinement of iron-based soft coordination suprapolymers.

    Science.gov (United States)

    Liang, Yawei; Xu, Limin; Zhou, Yinglin; Zhang, Xinxiang; Huang, Jianbin; Yan, Yun

    2013-10-14

    Currently there is intense interest in decreasing the operating potential for hydrogen evolution in water electrolysis to considerably decrease the energy cost. In this work we report a significant decrease of the operating potential for hydrogen evolution from neutral water mediated by an iron based soft coordination polymer (Fe(III)-SCSP). The creation of a local acidic environment with a thickness in the range of ~40 nm on the surface of a glassy carbon electrode allows enrichment of H(+) on the GCE, so that the operating potentials were effectively decreased. This strategy thus generates a new paradigm for lowering the operating potential of hydrogen generation from neutral water without the use of additional acids and organic cosolvents. PMID:23949627

  11. Detection of Salt Water Indicator with Electrolysis%电解用盐水指标检测

    Institute of Scientific and Technical Information of China (English)

    许红霞; 孙微微; 赵新苓

    2012-01-01

    Now the electrolysis is widely used to produce caustic soda in industry,and electrolytic salt solution produces caustic soda,chlorine,hydrogen.Salt dissolved in the crude Salt water contains many impurities,agents need to be refined by adding a variety of fine,and be refined into a qualified salt water,then be sent to the electrolysis process.Before and after sperm preparation is added,indicators of Salt water need to test.This paper examined the content of NaCl in coarse salt water,contents of NaOH and Na2CO3in salt water,and contents of Ca2+,Mg2+,SO42-and iron content in refined salt water.%目前工业生产烧碱普遍采用电解法,电解食盐水溶液产生烧碱、氯气、氢气。原盐溶解后得到的粗盐水含有许多杂质,需要加入各种精制剂进行精制,精制成合格的精盐水后,再送往电解工序。加入精制剂前后需要对盐水的指标进行检测,本文主要检测了粗盐水中NaCl含量,盐水中NaOH、Na2CO3的含量,精盐水中Ca2+、Mg2+、SO42-及铁离子含量。

  12. New Construction and Catalyst Support Materials for Water Electrolysis at Elevated Temperatures

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey

    in question are those for bipolar plates, gas diusion layers (GDLs), catalysts and catalyst supports. This work is focused on developing bipolar plate, GDL and catalyst support materials for the anode compartment of PEM electrolyzers, operating at elevated temperatures. The thesis starts with Chapter...... electrolysis. Chapter 4 reports results of testing dierent types of commercially available stainless steels, Ni-based alloys as well as titanium and tantalum as possible metallic bipolar plates and construction materials for HTPEMEC. The corrosion resistance was measured under simulated conditions of high...

  13. NiSn and porous NiZn coatings for water electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Santos, M.B.F.; Peres da Silva, E.; Andrade, R. Jr.; Dias, J.A.F. (Universidade Estadual de Campinas, SP (BR). Lab. de Hidrogenio)

    1992-01-01

    Porous Ni(Zn) coatings are prepared from the electrodeposition of NiZn alloys followed by chemical leaching in KOH solution. A pyrophosphate bath is used to electrodeposit NiSn alloys (14-84 at.% Sn). Polarization curves for hydrogen and oxygen evolution reactions in 28 wt% KOH solutions at 70{sup o}C are presented for selected Ni(Zn) and NiSn coatings. The electrocatalytic activity of a Ni(Zn) porous anode is maintained after 850 h of electrolysis, whereas the NiSn cathode loses its properties. (author).

  14. A Review on the Development of Water Electrolysis%电催化分解水研究进展

    Institute of Scientific and Technical Information of China (English)

    林红; 赵晓冲; 崔柏; 李建保

    2009-01-01

    能源问题是当今世界的热点问题之一.作为最重要的可再生清洁能源之一,氢能是解决当前能源危机的重要途径之一.本文综述了电解水制氢原理和目前电解水制氢的发展现状,并预测了电催化分解水制氢的发展与应用前景.%The energy problem has attracted great attention recently. As one of the most important clean and renewable energy, the production of hydrogen from water has become one of most promising solutions of energy problem. In this review,the mechanism,the state of the art and the outlook of the future development of water electrolysis are included.

  15. Effect of administration of water enriched in O2 by injection or electrolysis on transcutaneous oxygen pressure in anesthetized pigs

    Directory of Open Access Journals (Sweden)

    Charton A

    2014-08-01

    the three groups, but when compared to the control group, the values remained significantly higher in animals that received the water enriched in O2 by electrolysis. Conclusions: In this protocol, water enriched in O2 by electrolysis lessened the decline of peripheral tissue oxygenation. This observation is compatible with the claim that the electrolytic process generates water clathrates which trap O2 and facilitate O2 diffusion along pressure gradients. Potential applications of O2-enriched water include an alternate method of oxygen supply. Keywords: transcutaneous oxygen partial pressure determination, tissue oxygenation, oxygenated water, water clathrate 

  16. Transmutation in the electrolysis of light water - excess energy and iron production in a gold electrode

    International Nuclear Information System (INIS)

    The identification of some reaction products possibly produced during the generation of excess energy is attempted. Electrolysis is performed for 7 days with a constant current intensity of 1 A. The electrolytes used are Na2SO4, K2SO4, K2CO3, and KOH. After the electrolysis, the elements in the electrode near the surface are analyzed by Auger electron spectroscopy and electron probe microanalysis. In every case, a notable amount of iron atoms in the range of 1.0 x 1016 to 1.8 x 1017 atom/cm2 (true area) are detected together with the generation of a certain amount of excess energy evolution. The isotopic abundance of iron atoms, which are 6.5, 77.5, and 14.5% for 54Fe, 56Fe, and 57Fe, respectively, and are obviously different from the natural isotopic abundance, are measured at the top surface of a gold electrode by secondary ion mass spectrometry. The content of 57Fe tends to increase up to 25% in the more inner layers of the electrode. 8 refs., 11 figs., 3 tabs

  17. Mechanistic studies of water electrolysis and hydrogen electro-oxidation on high temperature ceria-based solid oxide electrochemical cells.

    Science.gov (United States)

    Zhang, Chunjuan; Yu, Yi; Grass, Michael E; Dejoie, Catherine; Ding, Wuchen; Gaskell, Karen; Jabeen, Naila; Hong, Young Pyo; Shavorskiy, Andrey; Bluhm, Hendrik; Li, Wei-Xue; Jackson, Gregory S; Hussain, Zahid; Liu, Zhi; Eichhorn, Bryan W

    2013-08-01

    Through the use of ambient pressure X-ray photoelectron spectroscopy (APXPS) and a single-sided solid oxide electrochemical cell (SOC), we have studied the mechanism of electrocatalytic splitting of water (H2O + 2e(-) → H2 + O(2-)) and electro-oxidation of hydrogen (H2 + O(2-) → H2O + 2e(-)) at ∼700 °C in 0.5 Torr of H2/H2O on ceria (CeO2-x) electrodes. The experiments reveal a transient build-up of surface intermediates (OH(-) and Ce(3+)) and show the separation of charge at the gas-solid interface exclusively in the electrochemically active region of the SOC. During water electrolysis on ceria, the increase in surface potentials of the adsorbed OH(-) and incorporated O(2-) differ by 0.25 eV in the active regions. For hydrogen electro-oxidation on ceria, the surface concentrations of OH(-) and O(2-) shift significantly from their equilibrium values. These data suggest that the same charge transfer step (H2O + Ce(3+) Ce(4+) + OH(-) + H(•)) is rate limiting in both the forward (water electrolysis) and reverse (H2 electro-oxidation) reactions. This separation of potentials reflects an induced surface dipole layer on the ceria surface and represents the effective electrochemical double layer at a gas-solid interface. The in situ XPS data and DFT calculations show that the chemical origin of the OH(-)/O(2-) potential separation resides in the reduced polarization of the Ce-OH bond due to the increase of Ce(3+) on the electrode surface. These results provide a graphical illustration of the electrochemically driven surface charge transfer processes under relevant and nonultrahigh vacuum conditions. PMID:23822749

  18. Electrochemical reactions at the electrode/solution interface:Theory and applications to water electrolysis and oxygen reduction

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Theoretical simulations on complex electrochemical processes have been developed on the basis of the understanding in electrochemistry,which has benefited from quantum mechanics calculations.This article reviews the recent progress on the theory and applications in electrocatalysis.Two representative reactions,namely water electrolysis and oxygen reduction,are selected to illustrate how the theoretical methods are applied to electrocatalytic reactions.The microscopic nature of these electrochemical reactions under the applied potentials is described and the understanding of the reactions is summarized.The thermodynamics and kinetics of the electrochemical reactions affected by the interplay of the electrochemical potential,the bonding strength and the local surface structure are addressed at the atomic level.

  19. Optimization of electrocatalytic properties of NiMoCo foam electrode for water electrolysis by post-treatment processing

    Institute of Scientific and Technical Information of China (English)

    Jian-Wei Wang; Yue-Fa Wang; Jing-Guo Zhang; Yan-Lin Yu; Ge-Ge Zhou; Lei Cheng; Lin-Shan Wang

    2015-01-01

    Hydrogen is a potential alternative to fossil fuels in coping with the increased global energy demand,and water electrolysis is an attractive approach for H2 production.Nickel-molybdenum-cobalt (NiMoCo) foam electrodes used for water electrolysis were prepared by the electrodeposition method,and the influence of heat treatments on the surface structure of NiMoCo foam electrodes,mechanical properties,and electrochemical performance of the synthesized electrodes was investigated in order to optimize the post-treatment processes.The residual carbon in the surface of the electrode was removed by decarbonization in the atmospheric condition.The carbon content decreases to lower than 200 × 10-6 when the temperature exceeds 500 ℃.Next,the material is reduced in hydrogen atmosphere from 500 to 1100 ℃ to remove the surface oxides.As the temperature increases,the surface molybdenum content increases significantly between 500 and 800 ℃,the surface grains become coarser,and the tensile strength and elongation increase as well.The lowest polarization overpotential is obtained at 800 ℃.Below 800 ℃,the electrode is only partially reduced and some black oxide zones are observed on the electrode surface,which leads to the higher polarization overpotential.The samples heat-treated at the temperatures of higher than 800 ℃ show better strength and toughness as well as brighter appearance.However,the surface particle coarsening leads to a decrease in the specific surface area and a higher overpotential.

  20. Degradation of Methyl Orange in Water by Contact Glow Discharge Electrolysis

    Institute of Scientific and Technical Information of China (English)

    GONG Jianying; CAI Weimin

    2007-01-01

    The degradation of methyl orange in a neutral phosphate buffer solution was investigated by means of contact glow discharge electrolysis (CGDE).The methyl oranges were degraded and eventually decomposed into inorganic carbon when CGDE was conducted under the applied DC voltage of 480 V and current of ca.80 mA.As the intermediate products,some phenolic compounds were detected as well as carboxylic acids.Experimental results showed that the oxidation process followed the first-order reaction law.Based on the analysis of the ultraviolet (UV) spectra of the solution and the intermediate products from High Pressure Liquid Chromatography-Mass Spectrum (HPLC-MS),the reaction pathway was proposed.The attack of hydroxyl radicals was considered to be a key step to start the whole oxidation process.

  1. On-board hydrogen storage and production: An application of ammonia electrolysis

    Science.gov (United States)

    Boggs, Bryan K.; Botte, Gerardine G.

    On-board hydrogen storage and production via ammonia electrolysis was evaluated to determine whether the process was feasible using galvanostatic studies between an ammonia electrolytic cell (AEC) and a breathable proton exchange membrane fuel cell (PEMFC). Hydrogen-dense liquid ammonia stored at ambient temperature and pressure is an excellent source for hydrogen storage. This hydrogen is released from ammonia through electrolysis, which theoretically consumes 95% less energy than water electrolysis; 1.55 Wh g -1 H 2 is required for ammonia electrolysis and 33 Wh g -1 H 2 for water electrolysis. An ammonia electrolytic cell (AEC), comprised of carbon fiber paper (CFP) electrodes supported by Ti foil and deposited with Pt-Ir, was designed and constructed for electrolyzing an alkaline ammonia solution. Hydrogen from the cathode compartment of the AEC was fed to a polymer exchange membrane fuel cell (PEMFC). In terms of electric energy, input to the AEC was less than the output from the PEMFC yielding net electrical energies as high as 9.7 ± 1.1 Wh g -1 H 2 while maintaining H 2 production equivalent to consumption.

  2. Polymer anion-selective membrane for electrolytic water splitting: the impact of a liquid electrolyte composition on the process parameters and long-term stability

    Czech Academy of Sciences Publication Activity Database

    Hnát, J.; Paidar, M.; Schauer, Jan; Bouzek, K.

    2014-01-01

    Roč. 39, č. 10 (2014), s. 4779-4787. ISSN 0360-3199 Institutional support: RVO:61389013 Keywords : water electrolysis * alkaline environment * polymer electrolyte Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.313, year: 2014

  3. Evaluation of a new Cr-free alloy as interconnect material for hydrogen production by high temperature water vapour electrolysis: Study in cathode atmosphere

    International Nuclear Information System (INIS)

    For economic and ecological reasons, hydrogen is considered as a major energetic vector for the future. Hydrogen production via high temperature water vapour electrolysis (HTE) is a promising technology. A major technical difficulty related to high temperature water vapour electrolysis is the development of interconnects working efficiently for a long period. Working temperature of 800 degrees C enables the use of metallic materials as interconnects. High temperature corrosion behaviour and electrical conductivity of a new Cr-free Fe-Ni-Co alloy were tested in cathode atmosphere (H2/H2O) at 800 degrees C. The alloy exhibits a poor oxidation resistance but an excellent ASR parameter, as a result of the formation of a highly-conductive Cr-free surface spinel layer. Moreover, the role of water vapour and hydrogen was discussed and a diffusion mechanism in cathode atmosphere could be suggested. (authors)

  4. Hydrogen production from inexhaustible supplies of fresh and salt water using microbial reverse-electrodialysis electrolysis cells.

    Science.gov (United States)

    Kim, Younggy; Logan, Bruce E

    2011-09-27

    There is a tremendous source of entropic energy available from the salinity difference between river water and seawater, but this energy has yet to be efficiently captured and stored. Here we demonstrate that H(2) can be produced in a single process by capturing the salinity driven energy along with organic matter degradation using exoelectrogenic bacteria. Only five pairs of seawater and river water cells were sandwiched between an anode, containing exoelectrogenic bacteria, and a cathode, forming a microbial reverse-electrodialysis electrolysis cell. Exoelectrogens added an electrical potential from acetate oxidation and reduced the anode overpotential, while the reverse electrodialysis stack contributed 0.5-0.6 V at a salinity ratio (seawater:river water) of 50. The H(2) production rate increased from 0.8 to 1.6 m(3)-H(2)/m(3)-anolyte/day for seawater and river water flow rates ranging from 0.1 to 0.8 mL/ min. H(2) recovery, the ratio of electrons used for H(2) evolution to electrons released by substrate oxidation, ranged from 72% to 86%. Energy efficiencies, calculated from changes in salinities and the loss of organic matter, were 58% to 64%. By using a relatively small reverse electrodialysis stack (11 membranes), only ~1% of the produced energy was needed for pumping water. Although Pt was used on the cathode in these tests, additional tests with a nonprecious metal catalyst (MoS(2)) demonstrated H(2) production at a rate of 0.8 m(3)/m(3)/d and an energy efficiency of 51%. These results show that pure H(2) gas can efficiently be produced from virtually limitless supplies of seawater and river water, and biodegradable organic matter. PMID:21930953

  5. Hydrogen production from inexhaustible supplies of fresh and salt water using microbial reverse-electrodialysis electrolysis cells

    KAUST Repository

    Kim, Y.

    2011-09-19

    There is a tremendous source of entropic energy available from the salinity difference between river water and seawater, but this energy has yet to be efficiently captured and stored. Here we demonstrate that H(2) can be produced in a single process by capturing the salinity driven energy along with organic matter degradation using exoelectrogenic bacteria. Only five pairs of seawater and river water cells were sandwiched between an anode, containing exoelectrogenic bacteria, and a cathode, forming a microbial reverse-electrodialysis electrolysis cell. Exoelectrogens added an electrical potential from acetate oxidation and reduced the anode overpotential, while the reverse electrodialysis stack contributed 0.5-0.6 V at a salinity ratio (seawater:river water) of 50. The H(2) production rate increased from 0.8 to 1.6 m(3)-H(2)/m(3)-anolyte/day for seawater and river water flow rates ranging from 0.1 to 0.8 mL/ min. H(2) recovery, the ratio of electrons used for H(2) evolution to electrons released by substrate oxidation, ranged from 72% to 86%. Energy efficiencies, calculated from changes in salinities and the loss of organic matter, were 58% to 64%. By using a relatively small reverse electrodialysis stack (11 membranes), only ~1% of the produced energy was needed for pumping water. Although Pt was used on the cathode in these tests, additional tests with a nonprecious metal catalyst (MoS(2)) demonstrated H(2) production at a rate of 0.8 m(3)/m(3)/d and an energy efficiency of 51%. These results show that pure H(2) gas can efficiently be produced from virtually limitless supplies of seawater and river water, and biodegradable organic matter.

  6. Fabrication of TiO2 Cathodes by Anodic Oxidation for Hydrogen Generation from Electrolysis of Water

    Directory of Open Access Journals (Sweden)

    *İ. Koyuncu

    2014-09-01

    Full Text Available In this investigation, titanium oxide plates were used as cathode for hydrogen production in the aqueous solutions of sulfuric acid, potassium hydroxide, acetic acid and ammonia hydroxides electrolytes separately. Gaseous hydrogen was produced at the cathode and oxygen at the anode. For this purpose, titanium plates were fabricated in acid solution by anodic oxidation. Microstructure of TiO2 nanorod observation was conducted with scanning electron microscopy (SEM. The effects of operating conditions and the electrochemical test parameters, such as electrolytes concentration, temperature, and cell voltage were investigated. Also the performance of TiO2 cathode was compared to zirconium oxide and graphite electrodes. The results show that the highly rated, hydrogen production performance on TiO2 cathode has better than the other electrodes. The maximum rate of hydrogen production is by TiO2 cathode 8.18 ml/ (h. cm2. The cell efficiency for water electrolysis was reached 95% using titanium oxide electrode in 1.5 M H2SO4.

  7. Rapid changes in water hardness and alkalinity: Calcite formation is lethal to Daphnia magna.

    Science.gov (United States)

    Bogart, Sarah J; Woodman, Samuel; Steinkey, Dylan; Meays, Cindy; Pyle, Greg G

    2016-07-15

    There is growing concern that freshwater ecosystems may be negatively affected by ever-increasing anthropogenic inputs of extremely hard, highly alkaline effluent containing large quantities of Ca(2+), Mg(2+), CO3(2-), and HCO3(-) ions. In this study, the toxicity of rapid and extreme shifts in water hardness (38-600mg/L as CaCO3) and alkalinity (30-420mg/L as CaCO3) to Daphnia magna was tested, both independently and in combination. Within these ranges, where no precipitation event occurred, shifts in water hardness and/or alkalinity were not toxic to D. magna. In contrast, 98-100% of D. magna died within 96h after exposure to 600mg/L as CaCO3 water hardness and 420mg/L as CaCO3 alkalinity (LT50 of 60h with a 95% CI of 54.2-66.0h). In this treatment, a CaCO3 (calcite) precipitate formed in the water column which was ingested by and thoroughly coated the D. magna. Calcite collected from a mining impacted stream contained embedded organisms, suggesting field streams may also experience similar conditions and possibly increased mortality as observed in the lab tests. Although further investigation is required to determine the exact fate of aquatic organisms exposed to rapid calcite precipitation in the field, we caution that negative effects may occur more quickly or at lower concentrations of water hardness and alkalinity in which we observed effects in D. magna, because some species, such as aquatic insects, are more sensitive than cladocerans to changes in ionic strength. Our results provide evidence that both calcite precipitation and the major ion balance of waters should be managed in industrially affected ecosystems and we support the development of a hardness+alkalinity guideline for the protection of aquatic life. PMID:27060657

  8. Electrochemical behavior of Ni-Mo electro catalyst for water electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez V, S. M.; Ordonez R, E. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Cabanas M, G. [IPN, Centro de Nanociencias y Micro y Nanotecnologias, A. P. 75-874, 07300 Mexico D. F. (Mexico); Solorza F, O., E-mail: suilma.fernandez@inin.gob.m [IPN, Centro de Investigacion y de Estudios Avanzados, Departamento de Quimica, A. P. 14-740, 07000 Mexico D. F. (Mexico)

    2010-07-01

    Nickel-molybdenum based electrocatalysts were synthesized in organic media for the hydrogen evolution reaction and oxygen evolution reaction in alkaline media. The structure, morphology and chemical composition of the catalysts were evaluated by X-ray diffraction, scanning electron microscopy and Aas. Results revealed nanocrystalline powder materials with Ni{sub 0.006}Mo, Ni{sub 0.1}Mo and Ni Mo compositions. The best performance for hydrogen evolution reaction, was obtained on Ni{sub 0.1}Mo electrode, whereas Ni Mo was for the oxygen evolution reaction. Results suggest that the material with 1:1 stoichiometric ratio could be considered as a promising electro catalyst for oxygen evolution reaction. This nanocrystalline powder is formed by Ni{sub 2}Mo{sub 3}O{sub 8} and a crystalline structure attributed to the possible formation of a Ni Mo cluster, becomes NiMoO{sub 4} after thermal treatment at 1073 K in air. The Ni Mo 1:1 cluster catalyst presented electrochemical stability during the oxygen evolution reaction. (Author)

  9. High Temperature Electrolysis

    DEFF Research Database (Denmark)

    Elder, Rachael; Cumming, Denis; Mogensen, Mogens Bjerg

    2015-01-01

    High temperature electrolysis of carbon dioxide, or co-electrolysis of carbon dioxide and steam, has a great potential for carbon dioxide utilisation. A solid oxide electrolysis cell (SOEC), operating between 500 and 900. °C, is used to reduce carbon dioxide to carbon monoxide. If steam is also...

  10. Molybdenum Carbide Nanoparticles on Carbon Nanotubes and Carbon Xerogel: Low-Cost Cathodes for Hydrogen Production by Alkaline Water Electrolysis.

    Science.gov (United States)

    Šljukić, Biljana; Santos, Diogo M F; Vujković, Milica; Amaral, Luís; Rocha, Raquel P; Sequeira, César A C; Figueiredo, José L

    2016-05-23

    Low-cost molybdenum carbide (Mo2 C) nanoparticles supported on carbon nanotubes (CNTs) and on carbon xerogel (CXG) were prepared and their activity for the hydrogen evolution reaction (HER) was evaluated in 8 m KOH aqueous electrolyte at 25-85 °C. Measurements of the HER by linear scan voltammetry allowed us to determine Tafel slopes of 71 and 74 mV dec(-1) at 25 °C for Mo2 C/CNT and Mo2 C/CXG, respectively. Stability tests were also performed, which showed the steady performance of the two electrocatalysts. Moreover, the HER kinetics at Mo2 C/CNT was enhanced significantly after the long-term stability tests. The specific activity of both materials was high, and a higher stability was obtained for the activated Mo2 C/CNT (40 A g(-1) at -0.40 V vs. the reversible hydrogen electrode). PMID:27101476

  11. Electrochemistry Modeling of Proton Exchange Membrane (PEM) Water Electrolysis for Hydrogen Production

    International Nuclear Information System (INIS)

    An electrochemistry model was developed to analyse the J-V characteristics of a Proton Exchange Membrane (PEM) water electrolyzer for hydrogen production. The Butler-Volmer equation and water transport characteristics through electrolyte membrane were employed to simulate the electrode activation over-potential and membrane ohmic over-potential, respectively. The modeling results are found to agree reasonably well with experimental data published in the literature. The parametric simulations show that the ohmic over-potential is relatively small with typical water content in the membrane. Compared with the cathode over-potential, the anode over-potential is more significant and constitutes the major source of voltage loss. The high anode over-potential is due to the relatively slow oxidation kinetics, which is related to anode material property and microstructure. This model can be integrated with a photovoltaic or wind turbine model to predict the performance of sustainable hydrogen production systems and optimise their designs. (authors)

  12. Decomposition of water with industrial oxygen sensor used as electrolysis cell

    International Nuclear Information System (INIS)

    Industrial solid state oxygen sensors, using fully stabilized zirconia as electrolyte, were modified and used to split water vapor, mixed with inert gas. Such conditions were chosen for simulating the tritium removal from the ceramic breeder materials in solid blanket fusion reactors. The single cell performances were investigated at 973 K and 200 cm3/min flow rate using argon/water vapor mixtures ranging from 100 to 700 vpm. The splitting efficiency was evaluated at 80%; steady state conditions were reached in a few minutes. 14 refs., 4 figs., 1 tab

  13. Current-Distribution Measurement in Polymer Electrolyte Water Electrolysis Equipment and Polymer Electrolyte Fuel Cell Using NMR Sensor

    Science.gov (United States)

    Yokouchi, Yasuo; Ogawa, Kuniyasu; Haishi, Tomoyuki; Ito, Kohei

    In a polymer electrolyte fuel cell (PEFC), the current density through the polymer electrolyte membrane (PEM) is distributed along the electrode on the membrane electrode assembly (MEA). To increase the electric power density of a PEFC, it is necessary to locate local decreases in current density where electric power generation decreases due to a lack of hydrogen, flooding, and so on. Therefore, achieving a higher current density in a PEFC requires monitoring the local current density. We developed a new method to estimate the spatial distribution of current flowing through the MEA in a polymer electrolyte water electrolysis equipment (PEWEE) and a PEFC using Nuclear-Magnetic-Resonance (NMR) sensors. The magnetic field strength induced by current through the MEA in a PEWEE is acquired as the frequency shift of the NMR signal which is measured by the NMR sensor. The spatial distributions of the frequency shifts occurring along the MEA in a PEWEE and a PEFC was measured. In order to verify the method, the magnetic field strength induced by the current through the gas diffusion layer (GDL) in a PEWEE was analyzed theoretically under the assumption that the current through MEA was uniform. The frequency shift was then calculated as a function of the geometry of the GDL, current, and the position of the NMR sensor. From experimental and theoretical results, the frequency shift of the NMR signal is proportional to current density and depends on the position of the sensors. Using the measurement system, we also obtained the current distribution through the GDL in a PEFC generating electric power. In these studies, the experimental and theoretical results agree.

  14. The Oxygen Evolution Reaction at Iridium-Ruthenium Oxide Catalysts for PEM Water Electrolysis

    OpenAIRE

    Thuv, Heidi

    2015-01-01

    A sustainable method for hydrogen production can be achieved with PEM water electrolysers. These are considered important for the transition to a society based on renewable energy production as they can be coupled with intermittent power sources like wind and solar power. One major challenge with this technology is the sluggish oxygen evolution in combination with the harsh conditions at the anode, requiring expensive catalyst materials. Mixed iridium-ruthenium oxides are promising electrocat...

  15. Stability and Degradation Mechanisms of Radiation-Grafted Polymer Electrolyte Membranes for Water Electrolysis.

    Science.gov (United States)

    Albert, Albert; Lochner, Tim; Schmidt, Thomas J; Gubler, L

    2016-06-22

    Radiation-grafted membranes are a promising alternative to commercial membranes for water electrolyzers, since they exhibit lower hydrogen crossover and area resistance, better mechanical properties, and are of potentially lower cost than perfluoroalkylsulfonic acid membranes, such as Nafion. Stability is an important factor in view of the expected lifetime of 40 000 h or more of an electrolyzer. In this study, combinations of styrene (St), α-methylstyrene (AMS), acrylonitrile (AN), and 1,3-diisopropenylbenzene (DiPB) are cografted into 50 μm preirradiated poly(ethylene-co-tetrafluoroethylene) (ETFE) base film, followed by sulfonation to produce radiation-grafted membranes. The stability of the membranes with different monomer combinations is compared under an accelerated stress test (AST), and the degradation mechanisms are investigated. To mimic the conditions in an electrolyzer, in which the membrane is always in contact with liquid water at elevated temperature, the membranes are immersed in water for 5 days at 90 °C, so-called thermal stress test (TST). In addition to testing in air atmosphere tests are also carried out under argon to investigate the effect of the absence of oxygen. The water is analyzed with UV-vis spectroscopy and ion chromatography. The ion exchange capacity (IEC), swelling degree, and Fourier transform infrared (FTIR) spectra of the membranes are compared before and after the test. Furthermore, energy-dispersive X-ray (EDX) spectroscopic analysis of the membrane cross-section is performed. Finally, the influence of the TST to the membrane area resistance and hydrogen crossover is measured. The stability increases along the sequence St/AN, St/AN/DiPB, AMS/AN, and AMS/AN/DiPB grafted membrane. The degradation at the weak-link, oxygen-induced degradation, and hydrothermal degradation are proposed in addition to the "swelling-induced detachment" reported in the literature. By mitigating the possible paths of degradation, the AMS

  16. Long-term evolution of highly alkaline steel slag drainage waters.

    Science.gov (United States)

    Riley, Alex L; Mayes, William M

    2015-07-01

    The disposal of slag generated by the steel industry can have negative consequences upon the surrounding aquatic environment by the generation of high pH waters, leaching of potentially problematic trace metals, and rapid rates of calcite precipitation which smother benthic habitats. A 36-year dataset was collated from the long-term ambient monitoring of physicochemical parameters and elemental concentrations of samples from two steel slag leachate-affected watercourses in northern England. Waters were typified by elevated pH (>10), high alkalinity, and were rich in dissolved metals (e.g. calcium (Ca), aluminium (Al), and zinc (Zn)). Long-term trend analysis was performed upon pH, alkalinity, and Ca concentration which, in addition to Ca flux calculations, were used to highlight the longevity of pollution arising as a result of the dumping and subsequent leaching of steel slags. Declines in calcium and alkalinity have been modest over the monitoring period and not accompanied by significant declines in water pH. If the monotonic trends of decline in alkalinity and calcium continue in the largest of the receiving streams, it will be in the region of 50-80 years before calcite precipitation would be expected to be close to baseline levels, where ecological impacts would be negligible. PMID:26108748

  17. Dose-dependent inhibition of gastric injury by hydrogen in alkaline electrolyzed drinking water

    OpenAIRE

    Xue, Jinling; Shang, Guodong; Tanaka, Yoshinori; Saihara, Yasuhiro; Hou, Lingyan; Velasquez, Natalia; Liu, Wenjun; Lu, Yun

    2014-01-01

    Background Hydrogen has been reported to relieve damage in many disease models, and is a potential additive in drinking water to provide protective effects for patients as several clinical studies revealed. However, the absence of a dose–response relationship in the application of hydrogen is puzzling. We attempted to identify the dose–response relationship of hydrogen in alkaline electrolyzed drinking water through the aspirin induced gastric injury model. Methods In this study, hydrogen-ric...

  18. A preliminary investigation of cold fusion by electrolysis of heavy water

    International Nuclear Information System (INIS)

    Several tests have been made with electrolytic cells utilizing 0.1 to 0.2 N LiOD in D2O as the electrolyte and a palladium cathode surrounded by a wire-wound platinum anode operating at cathode current densities of 100 to 600 mA/cm2. The cathodes were swaged to diameters of 2.8 or 5.5 mm with 8.0 to 8.5 cm of active length and then annealed in some tests. The electrolyte temperature was controlled and heat was removed by flowing water in a cooling jacket, and the cell was insulated. Cooling water and electrolyte temperatures were determined by thermocouples; neutron and gamma-ray spectra were measured; and the electrolyte was periodically analyzed for tritium. In one test, an internal wire coil of platinum coated with palladium black was used in a closed system to recombine the electrolytically generated D2 and O2 without release of any off-gas. The electrolyte was periodically sampled and electrolyte of the nominal concentration was added to replace the volume withdrawn; makeup D2O was also added, when required, in those experiments which did not include a recombiner. Neutron and gamma-ray spectra were recorded on magnetic media; temperatures, coolant flow rate, and voltages were recorded and, in the last two experiments, acquired by a computer data acquisition system. Tests up to 1000 h in duration were made, and in some experiments excess power was detected for periods of many hours, usually in the range of 5 to 15%. However, during one 12-h period, excess power of up to 50% was observed. On three separate occasions, the neutron count rate exceeded the background by three standard deviations; in addition, an apparent transient increase of tritium in the electrolyte by at least a factor of 25 occurred during one test. 8 refs., 14 figs., 3 tabs

  19. Hydrogen production by supercritical water gasification of alkaline black liquor

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Changqing; Guo, Liejin; Chen, Yunan; Lu, Youjun [Xi' an Jiatong Univ. (China)

    2010-07-01

    Black liquor was gasified continuously in supercritical water successfully and the main gaseous products were H{sub 2}, CO{sub 2} and CH{sub 4} with little amount of CO, C{sub 2}H{sub 4} and C{sub 2}H{sub 6}. The increase of the temperature and the decrease of the flow rate and black liquor concentration enhanced SCWG of black liquor. The change of the system pressure had limited influence on the gasification effect. The maximal COD removal efficiency of 88.69 % was obtained at the temperature of 600 C. The pH values of the aqueous residue were all decreased to the range of 6.4{proportional_to}8 while the pH value of cooling effluence below 360 C increased to about 11 and the sodium content was much higher than that in the aqueous residue. The reaction rate for COD degradation in supercritical water was obtained by assuming pseudo first order reaction. And the activation energy and pre-exponential for COD removal in SCWG were 74.38kJ/mol and 1.11 x 10{sup 4} s{sup -1} respectively. (orig.)

  20. Hydrogen production by water electrolysis by using ionic liquids as electrolytes; Producao de hidrogenio por eletrolise da agua usando liquidos ionicos como eletrolitos

    Energy Technology Data Exchange (ETDEWEB)

    Padilha, Janine Carvalho; Souza, Roberto Fernando de; Goncalves, Reinaldo Simoes [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Quimica; Rault-Berthelot, Joelle [Universite de Rennes, Rennes (France). Inst. de Chimie. Lab. de Eletroquimica Molecular e Macromolecular

    2006-07-01

    Imidazolium ionic liquids (ILs) such as BMI.BF{sub 4} and BMI.PF{sub 6} were studied by cyclic voltammetry (CV). BMI.BF{sub 4} was used as an electrolyte for hydrogen production through water electrolysis. The system using these ionic liquids in a conventional electrochemical cell with platinum electrodes at room temperature and atmospheric pressure gives current densities (j) higher than 20 m A.cm{sup -2} and efficiencies of more than 94.5%. The catalytic activity of the electrode surface was not affected during the electrolyses mainly due to the chemical stability of the IL. (author)

  1. Platinum Activated IrO2/SnO2 Nanocatalysts and Their Electrode Structures for High Performance Proton Exchange Membrane Water Electrolysis

    DEFF Research Database (Denmark)

    Xu, Junyuan; Li, Qingfeng; Christensen, Erik;

    2013-01-01

    In order to improve proton exchange membrane water electrolysis performance, anode catalyst and catalyst layer were examined in this work. SnO2 supported IrO2 nanocatalyst and its analogue with platinum enhancement were firstly synthesized for the oxygen evolution reaction. The effect of the...... introduction of Pt on the properties of the composites was explored by X-ray diffraction (XRD) and electrochemical test. Interaction between the introduced Pt nanoparticles and the bulk IrO2/SnO2 was evidenced in XRD. Electrochemical characterization showed the enhanced activitiy for the Pt activated IrO2/SnO2...

  2. GenHyPEM: A research program on PEM water electrolysis supported by the European Commission

    Energy Technology Data Exchange (ETDEWEB)

    Millet, Pierre; Dragoe, Diana [Institut de Chimie Moleculaire et des Materiaux d' Orsay, UMR CNRS no 8182, Universite Paris-Sud 11, 15 rue Georges Clemenceau, 91405 Orsay Cedex (France); Grigoriev, Serguey; Fateev, Vladimir [Hydrogen Energy and Plasma Technology, Institute of Russian Research Center, Kurchatov Institute, 1, Kurchatov sq., 123182 Moscow (Russian Federation); Etievant, Claude [Compagnie Europeenne des Technologies de l' Hydrogene (CETH), Innov' Valley Entreprise, Batiment D0, Route de Nozay, 91461 Marcoussis Cedex (France)

    2009-06-15

    GenHyPEM (Generateur d'Hydrogene par electrolyse de l'eau PEM <>) is an STREP programme (no 019802) supported by the European Commission in the course of the 6th framework research programme. This R and D project which started in October 2005, is a 2.6 MEUR research effort over three years. It gathers partners from Belgium, Germany, Romania, Federation of Russia, Armenia and France. The main goal of the project is to develop low-cost and high pressure (50 bar) PEM water electrolysers for the production of up to several Nm{sup 3} H{sub 2}/h. The purpose of this communication is to present the current status of GenHyPEM. Major results and technological achievements obtained so far in the fields of academic (electrocatalysis, polymer electrolyte) and applied (stack development and performances) research are presented. Non-noble electrocatalysts have been identified to replace platinum for the HER and stable performances have been obtained during operation at high (1 A cm{sup -2}) current density, paving the way to substantial cost reductions. Prototype electrolysers producing from 0.1 to 5 Nm{sup 3} H{sub 2}/h have been successfully developed. (author)

  3. Performance of metal compound on thermolysis and electrolysis on sugar industries waste water treatment: COD and color removal with sludge analysis (batch-experiment)

    Science.gov (United States)

    Sahu, Omprakash

    2016-06-01

    The sugar cane industry is one of the most water demanding industries. Sugar industries consume and generate excess amount of water. The generated water contains organic compounds, which would cause pollution. The aim of this research work is to study the effectiveness of metal compound for treatment of sugar industry waste water by thermolysis and electrolysis process. The result shows ferrous metal catalyst shows 80 and 85 % chemical oxygen demand and color removal at pH 6, optimum mass loading 4 kg/m3, treatment temperature 85 °C and treatment time 9 h. When ferrous material was used as electrode, maximum 81 % chemical oxygen demand and 84 % color removal at pH 6, current density 156 Am-2, treatment time 120 min and anode consumption 0.7 g for 1.5 L wastewater were obtained.

  4. Comparison of liquid hot water and alkaline pretreatments of giant reed for improved enzymatic digestibility and biogas energy production.

    Science.gov (United States)

    Jiang, Danping; Ge, Xumeng; Zhang, Quanguo; Li, Yebo

    2016-09-01

    Liquid hot water (LHW) and alkaline pretreatments of giant reed biomass were compared in terms of digestibility, methane production, and cost-benefit efficiency for electricity generation via anaerobic digestion with a combined heat and power system. Compared to LHW pretreatment, alkaline pretreatment retained more of the dry matter in giant reed biomass solids due to less severe conditions. Under their optimal conditions, LHW pretreatment (190°C, 15min) and alkaline pretreatment (20g/L of NaOH, 24h) improved glucose yield from giant reed by more than 2-fold, while only the alkaline pretreatment significantly (pelectrical energy production due to high energy input. Alkaline pretreatment achieved 27% higher net electrical energy production than that of non-pretreatment (3859kJ/kg initial total solids), but alkaline liquor reuse is needed for improved net benefit. PMID:27233098

  5. Development of conductometric biosensors based on alkaline phosphatases for the water quality control

    CERN Document Server

    Berezhetskyy, A

    2008-01-01

    Researches are focused on the elaboration of enzymatic microconductometric device for heavy metal ions detection in water solutions. The manuscript includes a general introduction, the first chapter contains bibliographic review, the second chapter described the fundamentals of conductometric transducers, the third chapter examining the possibility to create and to optimize conductometric biosensor based on bovine alkaline phosphatase for heavy metals ions detection, the fourth chapter devoted to creation and optimization of conductometric biosensor based on alkaline phosphatase active microalgae and sol gel technology, the last chapter described application of the proposed algal biosensor for measurements of heavy metal ions toxicity of waste water, general conclusions stating the progresses achieved in the field of environmental monitoring

  6. Hydrogen Generation From Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Steven Cohen; Stephen Porter; Oscar Chow; David Henderson

    2009-03-06

    Small-scale (100-500 kg H2/day) electrolysis is an important step in increasing the use of hydrogen as fuel. Until there is a large population of hydrogen fueled vehicles, the smaller production systems will be the most cost-effective. Performing conceptual designs and analyses in this size range enables identification of issues and/or opportunities for improvement in approach on the path to 1500 kg H2/day and larger systems. The objectives of this program are to establish the possible pathways to cost effective larger Proton Exchange Membrane (PEM) water electrolysis systems and to identify areas where future research and development efforts have the opportunity for the greatest impact in terms of capital cost reduction and efficiency improvements. System design and analysis was conducted to determine the overall electrolysis system component architecture and develop a life cycle cost estimate. A design trade study identified subsystem components and configurations based on the trade-offs between system efficiency, cost and lifetime. Laboratory testing of components was conducted to optimize performance and decrease cost, and this data was used as input to modeling of system performance and cost. PEM electrolysis has historically been burdened by high capital costs and lower efficiency than required for large-scale hydrogen production. This was known going into the program and solutions to these issues were the focus of the work. The program provided insights to significant cost reduction and efficiency improvement opportunities for PEM electrolysis. The work performed revealed many improvement ideas that when utilized together can make significant progress towards the technical and cost targets of the DOE program. The cell stack capital cost requires reduction to approximately 25% of today’s technology. The pathway to achieve this is through part count reduction, use of thinner membranes, and catalyst loading reduction. Large-scale power supplies are available

  7. The Nature of Surface Oxides on Corrosion-Resistant Nickel Alloy Covered by Alkaline Water

    OpenAIRE

    Gervasio DF; Cai Jiaying

    2010-01-01

    Abstract A nickel alloy with high chrome and molybdenum content was found to form a highly resistive and passive oxide layer. The donor density and mobility of ions in the oxide layer has been determined as a function of the electrical potential when alkaline water layers are on the alloy surface in order to account for the relative inertness of the nickel alloy in corrosive environments.

  8. Water Quality Based Design Guidelines for Successive Alkalinity-Producing Systems Used in the Treatment of Acidic Mine Drainage

    OpenAIRE

    Jage, Christopher Raymond

    2000-01-01

    Water Quality Based Design Guidelines for Successive Alkalinity-Producing Systems Used in the Treatment of Acidic Mine Drainage by Christopher Raymond Jage Carl Zipper, Chair Crop and Soil Environmental Sciences (ABSTRACT) Successive Alkalinity-Producing Systems (SAPS) have proven to be a viable alternative to chemical treatment for renovating acidic mine drainage (AMD). The lack of water quality based design guidelines, however, is believed to be a cause of the variability...

  9. Economic Analysis of Hydrogen Production by Photovoltaic Electrolysis

    OpenAIRE

    Gajardo, Luciano

    2014-01-01

    Awareness of the climate situation and greenhouse gas emissions from fossil fuels has focused attention on hydrogen as a renewable and sustainable energy resource. In this work an economic analysis of hydrogen production by a photovoltaic electrolysis system was conducted. Equations and solution methods from previous works [1, 2] have been used to compile the results. In order to run the electrolysis of water, electricity from the photovoltaic system was used. The photovoltaic electrolysis sy...

  10. Hydrogen production via urea electrolysis using a gel electrolyte

    Science.gov (United States)

    King, Rebecca L.; Botte, Gerardine G.

    2011-03-01

    A technology was demonstrated for the production of hydrogen and other valuable products (nitrogen and clean water) through the electrochemical oxidation of urea in alkaline media. In addition, this process remediates toxic nitrates and prevents gaseous ammonia emissions. Improvements to urea electrolysis were made through replacement of aqueous KOH electrolyte with a poly(acrylic acid) gel electrolyte. A small volume of poly(acrylic acid) gel electrolyte was used to accomplish the electrochemical oxidation of urea improving on the previous requirement for large amounts of aqueous potassium hydroxide. The effect of gel composition was investigated by varying polymer content and KOH concentrations within the polymer matrix in order to determine which is the most advantageous for the electrochemical oxidation of urea and production of hydrogen.

  11. Water quality improvement of a lagoon containing mixed chemical industrial wastewater by micro-electrolysis-contact oxidization

    Institute of Scientific and Technical Information of China (English)

    Ya-fei ZHOU; Mao LIU; Qiong WU

    2011-01-01

    A lagoon in the New Binhai District, a high-speed developing area, Tianjin, China, has long been receiving the mixed chemical industrial wastewater from a chemical industrial park. This lagoon contained complex hazardous substances such as heavy metals and accumulative pollutants which stayed over time with a poor biodegradability. According to the characteristics of wastewater in the lagoon, the micro-electrolysis process was applied to improve the biodegradability before the bioprocess treatment. By the orthogonal experimental study of main factors influencing the efficiency of the treatment method, the best control parameters were obtained, including pH=2.0, a volume ratio of Fe and reaction wastewater of 0.03750, a volume ratio of Fe and the granular activated carbon (GAC) of 2.0, a mixing speed of 200 r/min, and a hydraulic retention time (HRT) of 1.5 h. In the meantime, the removal rate of chemical oxygen demand (COD) was up to 64.6%, and NH4-N and Pb in the influent were partly removed. After the micro-electrolysis process, the ratio of biochemical oxygen demand (BOD) to COD (B/C ratio) was greater than 0.6, thus providing a favorable basis for bioprocess treatment.

  12. Electrolysis resistance reduced by magnetohydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, R.N. [Victoria Univ., Victoria, BC (Canada). Dept. of Chemistry

    2009-07-01

    The production of hydrogen by electrolysis of water has been known for many years, and the Nernst equation has been used to produce pressurized hydrogen. It has also been thought that the cost of hydrogen produced by electrolysis is higher than by steam reduction of natural gas. However, the consensus of opinion in research efforts is that hydrogen is at least 2.5 times the cost of gasoline per watt hour of energy. This paper described an experiment that used the main attributes of a cell outlined from Kirk-Othmer. Since the cell was difficult to construct and insufficient data was collected on the magnetohydrodynamic (MHD) process, a simpler, easily portable demonstration cell was devised. Experiments were run and the data were plotted both as impressed voltage at constant current versus time and resistance at constant current versus time. The cells were small, the electrolyte was enough to flood the cell and allow egress of hydrogen and oxygen. Since much of the raw data needed for a real calculation applicable to the industry was absent, only laboratory scale MHD scale experimental data was presented, and the volatile cost of petroleum was not assessed or included. It was not possible to claim that hydrogen was as cheap as gasoline for internal combustion engines or fuel cell cars, but water electrolysis in MHD conditions clearly rated consideration. 2 figs.

  13. Water removal studies on high power hydrogen-oxygen fuel cells with alkaline electrolytes

    Science.gov (United States)

    Kordesch, K.; Oliveira, J. C. T.; Gruber, Ch.; Winkler, G.

    1989-08-01

    Research in verification of bipolar fuel cell design, containing mass-produceable all-carbon electrodes which can be used in alkaline or acidic cells with liquid or immobilized (matrix) electrolytes, is described. Spin-offs from the research related to the Hermes manned spaceplane could be useful for applications on Earth. Peak-power plants, electric vehicles and storage devices used in combination with renewable energy sources could all benefit from the research. A subsequent investigation of water transpiration properties of carbon electrodes is described.

  14. Health Effects of Alkaline Diet and Water, Reduction of Digestive-tract Bacterial Load, and Earthing.

    Science.gov (United States)

    Mousa, Haider Abdul-Lateef

    2016-04-01

    In the article, the author discusses the issue of chronic, low-grade acidosis that is thought to be brought about primarily by 2 factors: (1) advancing age, with a consequent decline in renal function; and (2) diet. An acid-forming diet can induce low-grade metabolic acidosis, which causes very small decreases in blood pH and plasma bicarbonate (HCO3-) that remain within the range considered to be normal. However, if the duration of the acidosis is prolonged or chronically present, even a low degree of acidosis can become significant. This article reviews supporting evidence in the literature that has shown that consumption of abundant alkaline-forming foods can result in improvement in bone mineral density (BMD) and muscle mass, protection from chronic illnesses, reduced tumor-cell invasion and metastasis, and effective excretion of toxins from the body. In addition, a large number of studies showing the benefits of alkaline water (mineral water) have revealed that people consuming water with a high level of total dissolved solids (TDS) (ie, with a high mineral content) have shown a lower incidence of coronary heart disease (CHD), cardiovascular disease (CVD), and cancer and lower total mortality rates. Consumption of alkaline water also may prevent osteoporosis and protect pancreatic beta cells with its antioxidant effects. In addition, this article discusses the literature that shows that reducing digestive-tract bacterial load can play an important role in increasing blood alkalinity toward the normal upper limit. That change occurs through good oral hygiene, flossing of teeth, perfect chewing of food, and bowel evacuation as soon as possible. Finally, the author reviews the literature that shows that earthing (ie, the direct contact of the human body with the earth) can supply a current of plentiful electrons. Earthing has been shown to reduce acute and chronic inflammation, blood glucose in patients with diabetes, red blood cell (RBC) aggregation, and blood

  15. Microbial electrolysis cells as innovative technology for hydrogen production

    International Nuclear Information System (INIS)

    Hydrogen production is becoming increasingly important in view of using hydrogen in fuel cells. However, most of the production of hydrogen so far comes from the combustion of fossil fuels and water electrolysis. Microbial Electrolysis Cell (MEC), also known as Bioelectrochemically Assisted Microbial Reactor, is an ecologically clean, renewable and innovative technology for hydrogen production. Microbial electrolysis cells produce hydrogen mainly from waste biomass assisted by various bacteria strains. The principle of MECs and their constructional elements are reviewed and discussed. Keywords: microbial Electrolysis Cells, hydrogen production, waste biomass purification

  16. Alkaline regenerative fuel cell systems for energy storage

    Science.gov (United States)

    Schubert, F. H.; Reid, M. A.; Martin, R. E.

    1981-01-01

    A description is presented of the results of a preliminary design study of a regenerative fuel cell energy storage system for application to future low-earth orbit space missions. The high energy density storage system is based on state-of-the-art alkaline electrolyte cell technology and incorporates dedicated fuel cell and electrolysis cell modules. In addition to providing energy storage, the system can provide hydrogen and oxygen for attitude control of the satellite and for life support. During the daylight portion of the orbit the electrolysis module uses power provided by the solar array to generate H2 and O2 from the product water produced by the fuel cell module. The fuel cell module supplies electrical power during the dark period of the orbit.

  17. Cultivation of Pleurotus pulmonarius on substrates treated by immersion in alkaline water in Guerrero, Mexico

    Directory of Open Access Journals (Sweden)

    T. Bernabé-González

    2009-01-01

    Full Text Available Pleurotus pulmonarius was cultivated on dry banana leaves (Musa paradisiaca or dry "palmareca" leaves (Chrysalidocarpus lutescens, using two substrate treatments. Substrates were immersed in water containing 2% lime for 24 h and used for mushroom cultivation, in comparison with the method of immersing substrates in hot water at ±80 C for 1 h. The highest mushroom production was obtained on banana leaves immersed in alkaline water, reaching 120.1% of biological efficiency in a period of 61 days. Biological efficiency in the other treatments varied between 41.4-81.2%. Substrates and treatments studied are suitable for low-cost and small-scale production of oyster mushrooms.

  18. 太阳能光伏电解水制氢的实验研究%Experimental study on PV electrolysis of water for production of hydrogen

    Institute of Scientific and Technical Information of China (English)

    刘金亚; 张华; 雷明镜; 薛演振

    2014-01-01

    Based on photovoltaic effect and principle of hydrogen production by electrolysis of water,a PV water electrolysis device for hydrogen production is designed and several experimental researches on this system are carried out.The system is composed of solar photovoltaic panels,an accumulator,a DC electrolyzer,a controller,hydrogen gas measuring and collecting device.During day the system is powered by the PV device with redundant power being stored in the accumulator.Mains and the accumulator are combined to power this system at night.The experimental results show that the optimal electrolyte concentration of potassium hydroxide is 30%,the conversion efficiency of monocrystal silicon solar cell is 17.5% and the current efficiency of this system is 99.18%.%基于光生伏打效应和电解水制氢原理,设计出太阳能光伏电解水制氢装置并进行了实验研究.实验系统由太阳能光伏板、蓄电池、电解槽、氢气测量与收集装置和控制器等组成.该系统白天由太阳能光伏供电,蓄电池将多余电量保存;晚上由市电和蓄电联合供电.实验结果表明,电解液KOH浓度为30%时最为理想,此时单晶硅太阳能板的光电转换效率为17.5%,电解水制氢装置的电流效率为99.18%.

  19. Microscale Electrolysis Using Coin-Type Lithium Batteries and Filter

    Science.gov (United States)

    Kamata, Masahiro; Yajima, Seiko

    2013-01-01

    An educational experiment illustrates the electrolysis of water and copper chloride to middle school science students. The electrolysis cell is composed of filter paper soaked with Na[subscript 2]SO[subscript 4] or CuCl[subscript 2] aqueous solution sandwiched, along with a sheet of platinum foil, between two coin-type lithium batteries. When the…

  20. The impact of sedimentary alkalinity release on the water column CO2 system in the North Sea

    Science.gov (United States)

    Brenner, H.; Braeckman, U.; Le Guitton, M.; Meysman, F. J. R.

    2016-02-01

    It has been previously proposed that alkalinity release from sediments can play an important role in the carbonate dynamics on continental shelves, lowering the pCO2 of seawater and hence increasing the CO2 uptake from the atmosphere. To test this hypothesis, sedimentary alkalinity generation was quantified within cohesive and permeable sediments across the North Sea during two cruises in September 2011 (basin-wide) and June 2012 (Dutch coastal zone). Benthic fluxes of oxygen (O2), alkalinity (AT) and dissolved inorganic carbon (DIC) were determined using shipboard closed sediment incubations. Our results show that sediments can form an important source of alkalinity for the overlying water, particularly in the shallow southern North Sea, where high AT and DIC fluxes were recorded in near-shore sediments of the Belgian, Dutch and German coastal zone. In contrast, fluxes of AT and DIC are substantially lower in the deeper, seasonally stratified, northern part of the North Sea. Based on the data collected, we performed a model analysis to constrain the main pathways of alkalinity generation in the sediment, and to quantify how sedimentary alkalinity drives atmospheric CO2 uptake in the southern North Sea. Overall, our results show that sedimentary alkalinity generation should be regarded as a key component in the CO2 dynamics of shallow coastal systems.

  1. Effects of overlying water aeration on phosphorus fractions and alkaline phosphatase activity in surface sediment

    Institute of Scientific and Technical Information of China (English)

    Jianjun Chen; Shaoyong Lu; Yikun Zhao; Wei Wang; Minsheng Huang

    2011-01-01

    Microbial activity may influence phosphorus (P) deposit and release at the water sediment interface.The properties of DO (dissolved oxygen), pH, P fractions (TP, Ca-P, Fe-P, OP, IP), and APA (alkaline phosphatase activity) at the water sediment interface were measured to investigate microbial activity variations in surface sediment under conditions of two-month intermittent aeration in overlying water.Results showed that DO and TP of overlying water increased rapidly in the first week and then decreased gradually after 15 day of intermittent aeration.Microorganism metabolism in surface sediment increased pH and decreased DO and TP in the overlying water.After two-month intermittent aeration, APA and OP from surface sediment (0-2 crm) were both significantly higher than those from bottom sediment (6-8 cm) (p < 0.05), and surface sediment Fe-P was transferred to OP during the course of microorganism reproduction on the surface sediment.These results suggest that microbial activity and microorganism biomass from the surface sediment were higher than those from bottom sediment afar two-month intermittent aeration in the overlying water.

  2. Mathematical model of water transport in Bacon and alkaline matrix-type hydrogen-oxygen fuel cells

    Science.gov (United States)

    Prokopius, P. R.; Easter, R. W.

    1972-01-01

    Based on general mass continuity and diffusive transport equations, a mathematical model was developed that simulates the transport of water in Bacon and alkaline-matrix fuel cells. The derived model was validated by using it to analytically reproduce various Bacon and matrix-cell experimental water transport transients.

  3. Fused salt electrolysis

    International Nuclear Information System (INIS)

    Working conditions for zirconium preparation by fused salt electrolysis were studied. For such purpose, a cell was built for operation under argon atmosphere. A graphite crucible served as anode, with steel cathodes. Proper design allowed cathode rechange under the inert atmosphere. Cathodic deposits of zirconium powder occluded salts from the bath. After washing with both water and hydrochloric acid, the metallic powder was consolidated by fusion. Optimum operating conditions were found to arise from an electrolyte of 12% potassium hexafluorzirconate -88% sodium chloride, at 820 deg C and 5 A/cm2 cathodic current density. Deposits contained 35% of metal and current efficiency reached 66%. The powder contained up to 600 ppm of chlorine and 1.700 ppm of fluorine; after fusion, those amounts decreased to 2 ppm and 3 ppm respectively, with low proportion of metallic impurities. Though oxygen proportion was 4.500 ppm, it should be lowered by improving working conditions, as well as working on an ampler scale. (Author)

  4. Theoretical considerations and a simple method for measuring alkalinity and acidity in low-pH waters by gran titration

    Science.gov (United States)

    Barringer, J.L.; Johnsson, P.A.

    1996-01-01

    Titrations for alkalinity and acidity using the technique described by Gran (1952, Determination of the equivalence point in potentiometric titrations, Part II: The Analyst, v. 77, p. 661-671) have been employed in the analysis of low-pH natural waters. This report includes a synopsis of the theory and calculations associated with Gran's technique and presents a simple and inexpensive method for performing alkalinity and acidity determinations. However, potential sources of error introduced by the chemical character of some waters may limit the utility of Gran's technique. Therefore, the cost- and time-efficient method for performing alkalinity and acidity determinations described in this report is useful for exploring the suitability of Gran's technique in studies of water chemistry.

  5. Experimentale Study of Alkaline Precipitation on Thermal Process SeaWater Desalination Condition

    International Nuclear Information System (INIS)

    The experiment of alkaline precipitation by separated method has beencarry out. Experiment took please by heating sea water simulation with eachother consist of a).142 ppm bicarbonate and 400 ppm calcium ion b). 142 ppmbicarbonate and magnesium ion at temperature 40,50,60,70,80,90,100,110 and120 oC respectively by using autoclave. Sampling has been done periodicalfor 30 minute in interval 300 minute for each temperature. The calculation ofalkaline precipitation on each step calculated through the decreasing ofcalcium and magnesium concentration with analysis by AAS. From experimentdata have the information that alkaline precipitation have been formed since40 oC. From time variable have been the information that the precipitationformed at 30th minute rapidly. Whether at further time the increasing ofprecipitation are not significant. This phenomena can explained that at eachheating step from 40 oC bicarbonate ion be come decomposition with theresult carbonate and hydroxide ion and react with calcium and magnesium formcalcium carbonate and magnesium hydroxide. From this information could beimplemented as base for avoiding using chemical material in desalinationthermal process. (author)

  6. A study on the electrolysis of sulfur dioxide and water for the sulfur cycle hydrogen production process

    Science.gov (United States)

    1980-01-01

    Experimental electrolysis cells using various platinum catalyzed carbon electrodes were tested. When operated at 200 mA/sq cm current density using 50 w/o acid at 50 C and 1 atm, a reference cell required 1.22 volts and degraded rapidly. After several improvements were incorporated into electrodes and the test cell configuration, a later cell required only 0.77 volts under identical operating conditions. At a lower current density, 100 mA/sq cm, the cell required only 0.63 volts. Kinetic studies on metal electrodes, measurements of temperature effects on electrode kinetics, investigations of electrocatalytic activities of metal electrodes over a wide range of acid concentrations, cyclic voltametric studies and evaluation of alternate catalysts were also conducted. From diffusivity experiments, a cation exchange membrane material, P-4010, exhibited an excellent diffusion coefficient, more than two orders of magnitude lower than that of rubber. Ionic resistivity measurements of eight materials showed that microporous rubber had the lowest resistivity.

  7. Influence of Hydration Level on Polymer and Water Dynamics in Alkaline Anion Exchange Fuel Cell Membranes

    Science.gov (United States)

    Tarver, Jacob; Kim, Jenny; Tyagi, Madhu; Soles, Christopher; Tsai, Tsung-Han; Coughlin, Bryan

    2015-03-01

    Triblock copolymers based on poly(chloromethylstyrene)-b-poly(ethylene)-b-poly(chloromethylstyrene) can be quaternized to different extents to yield anion exchange membranes for alkaline fuel cells. In the absence of moisture, these membranes demonstrate bilayer lamellar morphology. Upon high levels of hydration, however, in-situ small angle neutron scattering reveals the emergence of higher-order diffraction peaks. This phenomena has previously been observed in analogous diblock copolymer-based membranes and has been attributed to the induction of a multilayer lamellar morphology in which selective striping of water occurs in the center of the ion-rich domain. By conducting humidity-resolved quasielastic neutron scattering (QENS) measurements using deuterated water, we are able to isolate differences in the pico- to nanosecond timescale dynamics of the hydrogenated membrane upon hydration. QENS measurements in the presence of a hydrogenated water source subsequently permit deconvolution and isolation of the translational and rotational dynamics of water as a function of relative humidity, revealing spatial and temporal changes in polymer and water motion at high levels of hydration.

  8. Temperature Sensitivity Analysis of High Temperature Steam Electrolysis System for Hydrogen Production

    International Nuclear Information System (INIS)

    In this study, the temperature sensitive analysis model of the high temperature steam electrolysis (HTSE) system was established through electrochemical method. Temperature sensitivity of the HTSE system was analyzed using this model. The concept of temperature sensitive coefficient was put forward originally. Qualitative researches show the temperature sensitive coefficient increase with operation temperatures increasing under various electrical efficiency (ηel), electrolysis efficiency (ηes), and thermal efficiency (ηth), which indicate the overall system efficiency of the HTSE system increases with operation temperatures increasing. And the temperature sensitive coefficient increase with ηel and ηth increasing, while ηes has little effect on the temperature sensitive coefficient. Quantitative researches show the temperature sensitive coefficient is 1.4 with the operation temperatures in the range of 750-950 degree C, which indicates the overall system efficiency increases about 10.5% and 12%, when the operation temperatures of the HTSE system are 800 and 900 degree C, respectively. Then the overall system efficiency of the actual HTGR coupled with HTSE system is as high as 55.8% and 56.5%, respectively, which is about two times higher than that of the conventional alkaline water electrolysis. (authors)

  9. Geochemical study of water-rock interaction processes on geothermal systems of alkaline water in granitic massif

    International Nuclear Information System (INIS)

    The study of geothermal systems developed within granitic massifs (with alkaline waters and reducing ORP values) is a topic of increasing scientific interest. These systems are a perfect natural laboratory for studying the water-rock interaction processes as they are defined by three main features: 1) long residence time of water within the system, 2) temperature in the reservoir high enough to favour reaction kinetics and finally, 3) the comparison of the chemistry of the incoming and outgoing waters of the system allows for the evaluation of the processes that have modified the water chemistry and its signature, The four geothermal systems considered in this paper are developed within granitic massifs of the Spanish Central Pyrenes; these systems were studied from a geochemical point of view, defining the major, trace and REE chemistry of both waters and host rocks and then characterizing the composition and geochemical evolution of the different waters. Bicarbonate-chloride-sodic and bicarbonate-sodic compositions are the most representative of the water chemistry in the deep geothermal system, as they are not affected by secondary processes (mixing, conductive cooling, etc). (Author)

  10. Integrated Microbial Electrolysis Cell (MEC) with an anaerobic Membrane Bioreactor (MBR) for low strength wastewater treatment, energy harvesting and water reclamation

    KAUST Repository

    Jimenez Sandoval, Rodrigo J.

    2013-11-01

    Shortage of potable water is a problem that affects many nations in the world and it will aggravate in a near future if pertinent actions are not carried out. Decrease in consumption, improvements in water distribution systems to avoid losses and more efficient water treatment processes are some actions that can be implemented to attack this problem. Membrane technology and biological processes are used in wastewater treatment to achieve high water quality standards. Some other technologies, besides water treatment, attempt to obtain energy from organic wastes present in water. In this study, a proof-of-concept was accomplished demonstrating that a Microbial Electrolysis Cell can be fully integrated with a Membrane Bioreactor to achieve wastewater treatment and harvest energy. Conductive hollow fiber membranes made of nickel functioned as both filter material for treated water reclamation and as a cathode to catalyze hydrogen production reaction. The produced hydrogen was subsequently converted into methane by hydrogenotrophic methanogens. Organic removal was 98.9% irrespective of operation mode. Maximum volumetric hydrogen production rate was 0.2 m3/m3d, while maximum current density achieved was 6.1 A/m2 (based on cathode surface area). Biofouling, an unavoidable phenomenon in traditional MBRs, can be minimized in this system through self-cleaning approach of hybrid membranes by hydrogen production. The increased rate of hydrogen evolution at high applied voltage (0.9 V) reduces the membrane fouling. Improvements can be done in the system to make it as a promising net energy positive technology for the low strength wastewater treatment.

  11. Design of a Simple and Cheap Water Electrolyser for the Production of Solar Hydrogen

    OpenAIRE

    Ram Prasad

    2009-01-01

    Commercially available conventional alkaline electrolyser and advanced polymer membrane electrolysers for water electrolysis are quite expensive. Taking into account this aspect, a very simple and cheap water electrolyser has been designed and fabricated utilising easily available economical materials for small scale production of hydrogen using renewable energy from photovoltaic panel. The construction details of the electrolyser with a schematic drawing of the experimental set...

  12. Steam electrolysis cell system and electrolyzing method

    International Nuclear Information System (INIS)

    The present invention concerns a method effective to the electrolysis of tritium water in a tritium recovering system of a thermonuclear fuel system. Namely, in a steam electrolysis cell system including integrally constituted multistage type cells and independently disposed single stage type cell, steams are supplied from upstream to the multistage type cell. A voltage is applied at such a level that the concentration of the steams in the vicinity of the single stage type cell situated at the downmost stream among the cells is not decreased to 0 to electrolyze steams. Then, not yet decomposed steams are introduced to the single stage cell to complete the electrolysis. The device can be simplified and steams can be electrolyzed efficiently. (N.H.)

  13. CONTROL OF CADMIUM CARBONATE PRECIPITATION INTERFERENCES DURING THE DIALYSIS OF CADMIUM IN HIGH BICARBONATE ALKALINITY AQUATIC-LIFE BIOASSAY WATERS

    Science.gov (United States)

    The precipitation of cadmium carbonate during the dialysis of cadmium in a high bicarbonate alkalinity natural water, was linked to a significant source of error when determining dialyzate cadmium concentrations. The relative standard deviation was reduced by approximately four-f...

  14. Apparent Km of mitochondria for oxygen computed from Vmax measured in permeabilized muscle fibers is lower in water enriched in oxygen by electrolysis than injection

    Directory of Open Access Journals (Sweden)

    Zoll J

    2015-07-01

    significantly lower with both electron donors in water enriched in O2 by electrolysis. This was not associated with any increase in the sensitivity of mitochondria to ADP; no significant difference was observed for the Km ADP between the two waters.Conclusion: In this experiment, a higher affinity of the mitochondria for O2 was observed in water enriched in O2 by electrolysis than by injection. This observation is consistent with the hypothesis that O2 diffusion can be facilitated in water enriched in O2 by the electrolytic process.Keywords: saponin-skinned fibers, mitochondrial respiration, glutamate–malate, TMPD–ascorbate, Km O2

  15. Climatological variations of total alkalinity and total inorganic carbon in the Mediterranean Sea surface waters

    Directory of Open Access Journals (Sweden)

    E. Gemayel

    2015-08-01

    Full Text Available A compilation of several cruises data from 1998 to 2013 was used to derive polynomial fits that estimate total alkalinity (AT and total inorganic carbon (CT from measurements of salinity and temperature in the Mediterranean Sea surface waters. The optimal equations were chosen based on the 10-fold cross validation results and revealed that a second and third order polynomials fit the AT and CT data respectively. The AT surface fit showed an improved root mean square error (RMSE of ±10.6 μmol kg−1. Furthermore we present the first annual mean CT parameterization for the Mediterranean Sea surface waters with a RMSE of ±14.3 μmol kg−1. Excluding the marginal seas of the Adriatic and the Aegean, these equations can be used to estimate AT and CT in case of the lack of measurements. The seven years averages (2005–2012 mapped using the quarter degree climatologies of the World Ocean Atlas 2013 showed that in surface waters AT and CT have similar patterns with an increasing eastward gradient. The surface variability is influenced by the inflow of cold Atlantic waters through the Strait of Gibraltar and by the oligotrophic and thermohaline gradient that characterize the Mediterranean Sea. The summer-winter seasonality was also mapped and showed different patterns for AT and CT. During the winter, the AT and CT concentrations were higher in the western than in the eastern basin, primarily due to the deepening of the mixed layer and upwelling of dense waters. The opposite was observed in the summer where the eastern basin was marked by higher AT and CT concentrations than in winter. The strong evaporation that takes place in this season along with the ultra-oligotrophy of the eastern basin determines the increase of both AT and CT concentrations.

  16. Simulating the Energy and Water Fluxes from Two Alkaline Desert Ecosystems over Central Asia

    Directory of Open Access Journals (Sweden)

    Chang-Qing Jing

    2016-01-01

    Full Text Available The Central Asia region is covered by vast desert ecosystems, where the characteristic of energy and water fluxes is different from other humid ecosystems. The application of land surface models (LSMs in arid and semiarid ecosystems was largely limited. This paper presents a detailed evaluation of Common Land Model (CoLM at two eddy covariance (EC sites in alkaline desert ecosystems over Central Asia. Simulations of the net radiation (Rnet, latent heat flux (Qle, sensible heat flux (Qh, and soil temperature showed that refined estimate of roughness length (Z0m significantly improved the performance of CoLM in simulating turbulent heat fluxes. Qle was increased but Qh was decreased, which were in better agreement with the observations from EC system. The results indicated that accurate parameterization of Z0m is of crucial importance for predicting energy and water fluxes in LSM when applied in Central Asia desert ecosystems. Sensitivity analysis regarding leaf area index (LAI, Z0m, and albedo (α showed that Rnet is very sensitive to α but Qle, Qh, and soil temperature (Tsoil are sensitively varying with the estimate of Z0m at the two EC sites over Central Asia.

  17. Water dipping and electrokinetic jointed remediation of chromium-contaminated soil without water electrolysis%铬污染土壤浸泡与无水电解电动联合修复实验

    Institute of Scientific and Technical Information of China (English)

    李东; 熊振; 聂杨; 黄彦; 王力

    2013-01-01

    对TCr质量分数为2 312 mg/kg的污染土壤进行7轮蒸馏水预浸泡处理,然后再进行无水电解电动修复.污染土壤经过水浸泡、85.4 h和203 h的无水电解电动修复后,TCr去除率分别为45%、67%和84%,表明预浸泡处理可以显著降低铬污染土壤电动修复的负荷.通过采用铁阳极和CuSO4阴极工作液,抑制水的电解,使Fe2+离子和SO42-离子分别替代H+离子和OH-离子进入土壤,可以提高铬(Ⅵ)的电迁移数,提高铬污染土壤电动修复的电流效率.%A heavily chromium-contaminated soil with total chromium (TCr) concentration of 2 312 mg/kg is dipped in distilled water seven times before electrokinetic remediation without water electrolysis (EKRWWE). The TCr removal rates of 45% , 67% and 84% are respectively achieved after water-dipping, 85. 4 h EKRWWE and 203 h EKRWWE in order, demonstrating that pre-dipping treatment is able to significantly reduce the load of EKRWWE. In order to prevent electrolysis of water, iron is used as anode and CuSO4 solution is used as cathode electrolyte. Consequently, Fe2+ ion instead of H+ ion and SO42- ion instead of OH- ion migrate into soil and a higher transference number of CrO42- ion is achieved which means a higher efficiency of electrokinetic remediation of chromium-contaminated soil.

  18. Critical anomalies of alkaline fading of phenolphthalein in the critical solution of 2-butoxyethanol + water.

    Science.gov (United States)

    Du, Zhongyu; Yin, Handi; Hao, Zhiguo; Zheng, Peizhu; Shen, Weiguo

    2013-12-14

    We have used three-wavelength UV-spectrophotometry to study the reaction of the alkaline fading of phenolphthalein in the critical solution of 2-butoxyethanol + water. It was found that when the temperature was far away from the critical point, the values of the natural logarithm of the rate constant k and the natural logarithm of the chemical equilibrium K determined in our experiments had good linear relationships with the reciprocal of temperature, which served as the backgrounds and were used for correcting k and K in the critical region. The critical slowing down of the reaction and the critical anomaly of the chemical equilibrium were detected near the critical point. The value of the critical exponent characterizing the slowing down effect of the reaction rate was obtained to be 0.156, which was close to the value 0.11 associated with the heat capacity divergence and agreed with the theoretical prediction. The experimental result also confirmed the theoretical prediction of 0.11 for the critical exponent characterizing the weak divergence of the singularity of the chemical equilibrium. PMID:24329072

  19. Control of alkaline stress corrosion cracking in pressurized-water reactor steam generator tubing

    International Nuclear Information System (INIS)

    Outer-diameter stress corrosion cracking (ODSCC) of alloy 600 (UNS N06600) tubings in steam generators of the Kori-1 pressurized-water reactor (PWR) caused an unscheduled outage in 1994. Failure analysis and remedy development studies were undertaken to avoid a recurrence. Destructive examination of a removed tube indicated axial intergranular cracks developed at the top of sludge caused by a boiling crevice geometry. A high ODSCC propagation rate was attributed to high local pH and increased corrosion potential resulting from oxidized copper presumably formed during the maintenance outage and plant heatup. Remedial measures included: (1) crevice neutralization by crevice flushing with boric acid (H3BO3) and molar ratio control using ammonium chloride (NH4Cl), (2) corrosion potential reduction by hydrazine (H2NNH2) soaking and suppression of oxygen below 20 ppb to avoid copper oxide formation, (3) titanium dioxide (TiO2) inhibitor soaking, and (4) temperature reduction of 5 C. Since application of the remedy program, no significant ODSCC has been observed, which clearly demonstrates the benefit of departing from an oxidizing alkaline environment. In addition, the TiO2 inhibitor appeared to have a positive effect, warranting further examination

  20. Pilot study on bromate reduction in ozonation of water with low carbonate alkalinities by carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    Ji Li; Li Zou; Lulu Guo; Jialin Ji

    2011-01-01

    A pilot study was carried out to explore the application of carbon dioxide for pH depression in a bubble column and its ability to inhibit bromate formation for water with a low alkalinity.Results showed that in the absence of ammonia,CO2 was capable of reducing bromate 38.0%-65.4% with one-unit pH depression.CO2 caused a slightly lower bromate reduction (4.2%) than did H2SO4 when the pH was depressed to 7.4,and a more a pronounced lower reduction (8.8%) when the pH was depressed to 6.9.In the presence of 0.20mg/L-N ammonia,bromate was largely inhibited with 73.9% reduction.When the pH was depressed to 7.4,CO2 and H2SO4 showed an 11.3% and 23.5% bromate reduction respectively,demonstrating that the joint use of CO2 and ammonia might be a plausible strategy of blocking all three bromate formation pathways.CO2 could be applied through the aeration diffuser together with ozone gas,resulting in a similar bromate reduction compared with the premixing method through Venturi mixer.

  1. Hydrogen production from inexhaustible supplies of fresh and salt water using microbial reverse-electrodialysis electrolysis cells

    OpenAIRE

    Kim, Younggy; Logan, Bruce E.

    2011-01-01

    There is a tremendous source of entropic energy available from the salinity difference between river water and seawater, but this energy has yet to be efficiently captured and stored. Here we demonstrate that H2 can be produced in a single process by capturing the salinity driven energy along with organic matter degradation using exoelectrogenic bacteria. Only five pairs of seawater and river water cells were sandwiched between an anode, containing exoelectrogenic bacteria, and a cathode, for...

  2. Water-free Alkaline Polymer-inorganic Acid Complexes with High Conductivity at Ambient Temperature

    Institute of Scientific and Technical Information of China (English)

    O.V.Chervakov; M.V.Andriianova; V.V.Riabenko; A.V.Markevich; E.M.Shembel; D.Meshri

    2007-01-01

    1 Results Recently increased interest is shown to proton conducting materials based on the alkaline polymer-inorganic acid complexes that is caused by a possibility of their application as the high-temperature electrolyte systems for various electrochemical devices (fuel cells,sensors,lithium power sources etc.).Complexes of inorganic acids with the alkaline polymers (polybenzimidazoles[1],polyvinylpyridines[2]) are characterized by high ionic conductivity at ambient temperatures (up to 10-2 Ω-1·cm-1) a...

  3. Studies on membrane acid electrolysis for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marco Antonio Oliveira da; Linardi, Marcelo; Saliba-Silva, Adonis Marcelo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Celulas a Combustivel e Hidrogenio], Email: saliba@ipen.br

    2010-07-01

    Hydrogen represents great opportunity to be a substitute for fossil fuels in the future. Water as a renewable source of hydrogen is of great interest, since it is abundant and can decompose, producing only pure H{sub 2} and O{sub 2}. This decomposition of water can be accomplished by processes such as electrolysis, thermal decomposition and thermochemical cycles. The electrolysis by membrane has been proposed as a viable process for hydrogen production using thermal and electrical energy derived from nuclear energy or any renewable source like solar energy. In this work, within the context of optimization of the electrolysis process, it is intended to develop a mathematical model that can simulate and assist in parameterization of the electrolysis performed by polymer membrane electrolytic cell. The experimental process to produce hydrogen via the cell membrane, aims to optimize the amount of gas produced using renewable energy with noncarbogenic causing no harm by producing gases deleterious to the environment. (author)

  4. Comparative study of algal communities in acid and alkaline waters from Tinto, Odiel and Piedras river basins (SW Spain)

    OpenAIRE

    Urrea Clos, Gemma; Sabater, Sergi

    2009-01-01

    The distribution patterns of benthic algal assemblages in the Tinto, Odiel and Piedras rivers were analyzed during the winter of 2005 in 18 sampling stations. The main objective was to assess and compare the algal communities and parameters affecting them both in the zones affected by acid mine drainage (AMD) and in naturally alkaline waters. A total of 108 benthic diatom taxa and 31 non-diatom taxa were identi ed. Results showed large differences between algal communities in the two environm...

  5. Hydrogen Production from Nuclear Energy via High Temperature Electrolysis

    International Nuclear Information System (INIS)

    This paper presents the technical case for high-temperature nuclear hydrogen production. A general thermodynamic analysis of hydrogen production based on high-temperature thermal water splitting processes is presented. Specific details of hydrogen production based on high-temperature electrolysis are also provided, including results of recent experiments performed at the Idaho National Laboratory. Based on these results, high-temperature electrolysis appears to be a promising technology for efficient large-scale hydrogen production

  6. Development of Refractory Ceramics for The Oxygen Evolution Reaction (OER) Electrocatalyst Support for Water Electrolysis at elevated temperatures

    OpenAIRE

    Nikiforov, Aleksey; Prag, Carsten Brorson; Polonsky, J; Petrushina, Irina; Christensen, Erik; Bjerrum, Niels

    2012-01-01

    Commercial TaC and Si3N4 powders were tested as possible electrocatalyst support materials for the Oxygen Evolution Reaction (OER) for PEM water electrolysers, operating at elevated temperatures. TaC and Si3N4 were characterised by thermogravimmetric and differential thermal analysis for their thermal stability. The Adams fusion method was implemented to deposit IrO2 on the support surfaces. A series of electrocatalysts was prepared with a composition of (IrO2)x(TaC/ Si3N4)1-x,where x represe...

  7. Development of Refractory Ceramics for The Oxygen Evolution Reaction (OER) Electrocatalyst Support for Water Electrolysis at elevated temperatures

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Prag, Carsten Brorson; Polonsky, J.;

    2012-01-01

    Commercial TaC and Si3N4 powders were tested as possible electrocatalyst support materials for the Oxygen Evolution Reaction (OER) for PEM water electrolysers, operating at elevated temperatures. TaC and Si3N4 were characterised by thermogravimmetric and differential thermal analysis for their......-film method was used for electrochemical analysis of the prepared electrocatalysts. SEMEDX, BET and powder conductivity measurements were used as complementary techniques to complete characterisation of the electrocatalysts. Additionally, they were compared in their properties with previously reported data...

  8. Study of a water electrolysis system using a compact solar cell module with a plant shoot configuration

    Energy Technology Data Exchange (ETDEWEB)

    Obara, Shin' ya [Department of Electrical and Electronic Engineering, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507 (Japan)

    2010-01-15

    The system proposed in this paper produces hydrogen by supplying photovoltaic power to a water electrolyzer and then supplying this gas to a fuel cell with a time shift. The objective of this system is to supply power to an individual house or apartment building with only green energy. However, the solar cell module installation area is large in the proposed system. Therefore, this paper considered installing a solar cell module with a plant shoot configuration. As a result of this modification, the power generation area of the proposed system is 33-52% smaller than that of a conventional flat solar cell module. From these results, it should be possible to introduce the proposed system into an individual house. (author)

  9. Electrolysis activities at FCH Test Center

    DEFF Research Database (Denmark)

    Ravn Nielsen, Eva; Nygaard, Frederik Berg

    FCH Test Center for fuel cell and hydrogen technologies was established in 2010 at Risø DTU in Denmark. Today, the test center is part of DTU Energy Conversion. The center gives industry access to advanced testing and demonstration of components and systems. A number of national projects and EU p...... projects regarding water electrolysis involve FCH Test Center as a partner. This presentation gives an overview of the activities....

  10. Exergetic/energetic/economic analysis of three hydrogen production processes: electrolysis, hybrid, and thermochemical

    International Nuclear Information System (INIS)

    This paper presents the results of a combined first and second law analysis, along with capital and operating costs, for hydrogen production from water by means of electrolytic, hybrid, and thermochemical processes. The processes are SPE and Lurgi electrolysis with light water reactor power generation and sulfur cycle hybrid, thermochemical and SPE electrolysis with a very high temperature reactor primary energy source. 15 refs

  11. Debromination and decomposition of bromoform by contact glow discharge electrolysis in an aqueous solution

    International Nuclear Information System (INIS)

    Bromoform (BF) is a stable and carcinogenic contaminant in water. In this study, efficient debromination and decomposition of BF induced by contact glow discharge electrolysis (CGDE) in a sodium sulfate solution were investigated. Intermediate byproducts were determined by ionic chromatography and gas chromatography, respectively. Experimental results showed that alkaline conditions and additions of organic additives to the solution were favorable for both the removal and the debromination of BF. Oxalic acid, formic acid, dibromomethane and bromate ion were determined as the major intermediate byproducts. Final products were inorganic carbon and bromide ion. Hydrated electrons may be the most likely active species responsible for the initiation of the debromination, and hydroxyl radicals may be the ones for the oxidation of the intermediate byproducts

  12. Hydrogen production by high-temperature electrolysis of steam

    International Nuclear Information System (INIS)

    Hydrogen production by high-temperature electrolysis of steam is a reverse process of a solid oxide fuel cell under development in the world. It is a simple and efficient process to produce hydrogen from water theoretically. In JAERI, bench-scale tests using an electrolysis tube have been conducted to investigate electrolysis characteristics and to accumulate operational know-how for a plant with is a utility system of high temperature heat from high temperature gas-cooled reactors. An electrolysis tube was fabricated by connecting 12 electrolysis cells in series. The cell consisted of multi-layers of an electrolyte and electrodes coated on a base ceramic tube. The electrolyte layer was made of yttria-stabilized zirconia. In the test, steam was supplied with argon gas as a carrier gas and DC power to the electrolyte through the electrodes. Hydrogen production rate increased with the applied power and the electrolysis temperature. The maximum production rate was 7.6 NL/h at 950 deg. C and the applied power of 27W. (author). 5 refs, 7 figs, 1 photo

  13. Facile synthesis of water-soluble carbon nano-onions under alkaline conditions

    Science.gov (United States)

    Ahmed, Gaber Hashem Gaber; Laíño, Rosana Badía; Calzón, Josefa Angela García

    2016-01-01

    Summary Carbonization of tomatoes at 240 °C using 30% (w/v) NaOH as catalyst produced carbon onions (C-onions), while solely carbon dots (C-dots) were obtained at the same temperature in the absence of the catalyst. Other natural materials, such as carrots and tree leaves (acer saccharum), under the same temperature and alkaline conditions did not produce carbon onions. XRD, FTIR, HRTEM, UV–vis spectroscopy, and photoluminescence analyses were performed to characterize the as-synthesized carbon nanomaterials. Preliminary tests demonstrate a capability of the versatile materials for chemical sensing of metal ions. The high content of lycopene in tomatoes may explain the formation of C-onions in alkaline media and a possible formation mechanism for such structures was outlined. PMID:27335764

  14. 钛涂铂电极在电解功能水机中的应用研究%Study on application of platinum-coated titanium electrode to electrolysis functional water producing device

    Institute of Scientific and Technical Information of China (English)

    罗小军; 徐永海; 张招贤

    2009-01-01

    钛涂铂电极是近年来活跃应用在电解功能水机中的一种新型电极材料.本文介绍了钛涂铂电极制造的工艺条件,用扫描电镜对钛涂铂电极表面形貌进行了表征.采用电化学工作站,在三电极体系中测试了钛涂铂电极析氧极化曲线及循环伏安曲线.测试数据表明,在水电解中,钛涂铂电极析氧活性高于钛镀铂电极.%Pt-coated titanium electrode, a new electrode material was applied actively to electrolysis functional water producing device. This paper introduced a preparation process of Pt-coated titanium electrode, and the surface morphology of the coating was characterized by scanning electron microscopy. The oxygen evolution polarization curves and cyclic voltammetric curve of Pt-coated titanium electrode were tested using an electrochemical workstation with three electrode system. Test data indicated that the oxygen evolution activity of the Pt-coated titanium electrode is higher than that of a platinized titanium electrode in water electrolysis.

  15. Spectroscopic Speciation of Plutonium Reduced by Electrolysis

    International Nuclear Information System (INIS)

    The oxidation state of plutonium should be carefully controlled to understand the chemical behaviors of plutonium. Pu(III) is not stable in aqueous solutions and easily oxidized in the atmosphere. In deep geological environments excluded oxygen, reducing condition is expected and will lead to rather stable Pu(III), which is very soluble compared to Pu(IV). Pu(III) ions are expected to form hydrolysis complexes in neutral and basic solutions similar to Am(III), Cm(III) and Eu(III). The reported formation constants of Pu(OH)n3-n (n=1-4) had been critically discussed, and only the first hydrolysis constant (log*β011 = -6.9 ± 0.3) was selected in a review. The main reason for the large discrepancy of the formation constants for Pu(OH)n3-n (n=2-4) is the high tendency of oxidation of Pu(III). In the present study, the reduction condition of Pu(III) was controlled by electrolysis. The electrolysis reactor was specially designed to investigate hydrolysis, colloid formation, and solubility of Pu(III) at different pHs. Pu(III) was reduced from higher oxidation states at acidic conditions, and the H+ ion concentration in solutions was simultaneously decreased without the addition of alkaline solution by electrolysis. The soluble species was investigated using spectrophotometry adopting a capillary cell (LWCC, Liquid Waveguide Capillary Cell, WPI) and the formation of plutonium colloid and solubility was determined using LIBD (Laser Induced Breakdown Detection). In this study, an electrolysis system for the reduction of plutonium and H+ ions in a solution with small volume (> 2 mL) was installed in a glove box to investigate the hydrolysis, colloid formation and solubility of Pu(III) under a reducing condition. Pu(III) was reduced from the mixed plutonium oxidation states without the generation of Pu(IV) colloidal particles or precipitates under weak acidic conditions. A coulometric titration method was applied to adjust the pH without the addition of NaOH. The change of

  16. Alkaline static feed electrolyzer based oxygen generation system

    Science.gov (United States)

    Noble, L. D.; Kovach, A. J.; Fortunato, F. A.; Schubert, F. H.; Grigger, D. J.

    1988-01-01

    In preparation for the future deployment of the Space Station, an R and D program was established to demonstrate integrated operation of an alkaline Water Electrolysis System and a fuel cell as an energy storage device. The program's scope was revised when the Space Station Control Board changed the energy storage baseline for the Space Station. The new scope was aimed at the development of an alkaline Static Feed Electrolyzer for use in an Environmental Control/Life Support System as an oxygen generation system. As a result, the program was divided into two phases. The phase 1 effort was directed at the development of the Static Feed Electrolyzer for application in a Regenerative Fuel Cell System. During this phase, the program emphasized incorporation of the Regenerative Fuel Cell System design requirements into the Static Feed Electrolyzer electrochemical module design and the mechanical components design. The mechanical components included a Pressure Control Assembly, a Water Supply Assembly and a Thermal Control Assembly. These designs were completed through manufacturing drawing during Phase 1. The Phase 2 effort was directed at advancing the Alkaline Static Feed Electrolyzer database for an oxygen generation system. This development was aimed at extending the Static Feed Electrolyzer database in areas which may be encountered from initial fabrication through transportation, storage, launch and eventual Space Station startup. During this Phase, the Program emphasized three major areas: materials evaluation, electrochemical module scaling and performance repeatability and Static Feed Electrolyzer operational definition and characterization.

  17. Magnetic Resonance Imaging of Electrolysis.

    Science.gov (United States)

    Meir, Arie; Hjouj, Mohammad; Rubinsky, Liel; Rubinsky, Boris

    2015-02-01

    This study explores the hypothesis that Magnetic Resonance Imaging (MRI) can image the process of electrolysis by detecting pH fronts. The study has relevance to real time control of cell ablation with electrolysis. To investigate the hypothesis we compare the following MR imaging sequences: T1 weighted, T2 weighted and Proton Density (PD), with optical images acquired using pH-sensitive dyes embedded in a physiological saline agar solution phantom treated with electrolysis and discrete measurements with a pH microprobe. We further demonstrate the biological relevance of our work using a bacterial E. Coli model, grown on the phantom. The results demonstrate the ability of MRI to image electrolysis produced pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E. Coli model grown on the phantom. The results are promising and invite further experimental research.

  18. Production of neutron and tritium from D2O electrolysis with palladium cathode

    International Nuclear Information System (INIS)

    Anomalous neutron burst and an increase in tritium concentration were observed simultaneously from heavy water electrolysis with palladium cathode. Considered with previous experiment results, we presumed that production of neutron and tritium from D2O electrolysis depends heavily on the constitution and the state of each cathode. (author)

  19. Hydrogen production through biocatalyzed electrolysis

    OpenAIRE

    Rozendal, R.A.

    2007-01-01

    cum laude graduation (with distinction) To replace fossil fuels, society is currently considering alternative clean fuels for transportation. Hydrogen could be such a fuel. In theory, large amounts of renewable hydrogen can be produced from organic contaminants in wastewater. During his PhD research René Rozendal has developed a new technology for this purpose: biocatalyzed electrolysis. The innovative step of biocatalyzed electrolysis is the application of electrochemically active microorgan...

  20. Facile synthesis of water-soluble carbon nano-onions under alkaline conditions

    OpenAIRE

    Ahmed, Gaber Hashem Gaber; Laíño, Rosana Badía; Calzón, Josefa Angela García; García, Marta Elena Díaz

    2016-01-01

    Carbonization of tomatoes at 240 °C using 30% (w/v) NaOH as catalyst produced carbon onions (C-onions), while solely carbon dots (C-dots) were obtained at the same temperature in the absence of the catalyst. Other natural materials, such as carrots and tree leaves (acer saccharum), under the same temperature and alkaline conditions did not produce carbon onions. XRD, FTIR, HRTEM, UV–vis spectroscopy, and photoluminescence analyses were performed to characterize the as-synthesized carbon nanom...

  1. Tritium enrichment of environmental waters by electrolysis: Development of cathodes exhibiting high isotopic separation and precise measurement of tritium enrichment factors

    International Nuclear Information System (INIS)

    Equations are developed for the estimation of tritium enrichment in batch, continuous feed and periodic addition electrolysis cells. Optimum enrichment and minimum variability is obtained using developed cathode surfaces which catalyse the separation of tritium, as exhibited by the results of experiments using mild steel cathodes with NaOH electrolyte. The equations and various simple refinements of technique are applied to the determination of tritium enrichment factors by the spike cell method: for batch cells the standard errors are less than 1%. (author)

  2. Solução oxidante gerada a partir da eletrólise de rejeitos de dessalinizadores de água Oxidant solution generated by electrolysis from residue of water desalinators

    Directory of Open Access Journals (Sweden)

    Jeruza Feitosa de Matos

    2006-06-01

    Full Text Available Neste trabalho foram realizados estudos para a produção de solução oxidante a partir de rejeito de dessalinizadores de água pelo processo de eletrólise, visando a sua utilização como desinfetante. O experimento foi realizado em escala de laboratório. Três soluções oxidantes foram geradas eletroliticamente, a partir de rejeitos de dessalinizadores de água com concentrações de 1,7 x 10³ mg; 5,5 x 10³ mg e 10,2 x 10³ mg de Cl-/L. O processo de eletrólise tinha duração de oito horas e, a cada hora da reação, o pH, a condutividade elétrica, a temperatura e o cloro total eram monitorados. Foi observado que a produção de cloro está diretamente relacionada com a concentração de cloreto; o teor médio de cloro das soluções oxidantes geradas foi de 0,10%; 0,24 % e 0,27 % m/m.This work carried out studies about the use of the electrolysis process to produce oxidant solutions from water desalinators wastes for water disinfection. The experiment was conducted in laboratory scale. Three oxidant solutions were generated by electrolysis from wastes of water desalinators that presented concentrations of 1.7 x 10³ mg, 5.5 x 10³ mg and 10.2 x 10³ mg of Cl-/L.The electrolysis process lasted eight hours and the following parameters were monitored every hour: pH, electrical conductivity, temperature, total chlorine. It was observed that the production of chlorine is directly related to chloride concentration; the average content of chlorine of the oxidant solutions generated from the desalinators wastes was 0.10%, 0.24% and 0.27% m/m.

  3. Distribution of total alkalinity and pH in the Ross Sea (Antarctica waters during austral summer 2008

    Directory of Open Access Journals (Sweden)

    Paola Rivaro

    2014-10-01

    Full Text Available Measurements of total alkalinity (AT and pH were made in the Ross Sea in January–February 2008 in order to characterize the carbonate system in the Ross Sea and to evaluate the variability associated with different water masses. The main water masses of the Ross Sea, Antarctic Surface Water, High Salinity Shelf Water (HSSW, Deep Ice Shelf Water, Circumpolar Deep Water (CDW and Antarctic Bottom Water, were identified on the basis of the physical and chemical data. In particular, the AT ranged between 2275 and 2374 µmol kg−1 with the lowest values in the surface waters (2275–2346 µmol kg−1, where the influence of the sea-ice melting and of the variability of the physical properties was significant. In the deep layers of the water column, the AT maxima were measured in correspondence to the preferential pathways of the spreading HSSW. The pH had variable values in the surface layer (7.890–8.033 with the highest values in Terra Nova Bay and Ross Sea polynyas. A low pH (7.969±0.025 traced the intrusion of the CDW in the Ross Sea shelf area. All samples revealed waters that were oversaturated with respect to both calcite and aragonite, but near corrosive levels of aragonite saturation state (Ω ca. 1.1–1.2 were associated with the entrainment of CDW over the slope. Aragonite undersaturation is of particular concern for the zooplankton species comprising to calcifying organisms such as pteropods. The partial pressure of CO2 at the sea surface was undersaturated with respect to the atmospheric value, particularly in Terra Nova Bay and the Ross Sea polynyas, but a large variability in the sea–air CO2 fluxes was observed associated with different responses in the strength of the biological and physical processes.

  4. Influence of sediment organic enrichment and water alkalinity on growth of aquatic isoetid and elodeid plants

    DEFF Research Database (Denmark)

    Raun, Ane-Marie Løvendahl; Borum, Jens; Jensen, Kaj Sand

    2010-01-01

    ) increasing alkalinity (from 0.17 to 3.20 meq. L-1) enhances growth and reduces inhibition of organic sediment enrichment for elodeids but not for isoetids. 2. In low organic sediments, higher oxygen release from roots of isoetids than elodeids generated oxic conditions to greater sediment depth for Lobelia...... two elodeids (Potamogeton crispus and P. perfoliatus), we test whether organic enrichment of lake sediments has a long-lasting influence by: (i) reducing plant growth because of oxygen stress on plant roots and (ii) inhibiting growth more for isoetids than elodeids. We also test whether (iii...... because of greater CO2 supply from sediments being their main CO2 source. At higher organic enrichment, isoetid biomass was reduced, leaf chlorophyll declined up to 10-fold, root length declined from 7 to <2 cm and mortality rose (up to 50%) signalling high plant stress. 4. Lobelia was not affected by HCO...

  5. Immobilization of B, F, Cr, and As in alkaline coal fly ash through an aging process with water.

    Science.gov (United States)

    Ogawa, Yasumasa; Sakakibara, Kento; Wang, Li; Suto, Koichi; Inoue, Chihiro

    2014-10-01

    Fourteen different alkaline coal fly ashes (CFAs) were used for the experiment, in which each sample was mixed with water to be 28.6% of water content (wt/wt) and aged for 1-4 weeks at 10-30 °C. This simple treatment is advantageous for decreases in water-soluble B, F, Cr, and As. Compared to non-aged CFAs, their water-soluble fractions remained 0.56-88%, 21-85%, 0.37-93% and 2.6-88%, respectively, after aging for a week at 20 °C, although the amounts of Cr and As released from some CFA samples increased. Considering the significant decrease in elution of sulfate, Ca and Al after aging, the immobilization, namely prevention of toxic element elution, could be related to formation of secondary minerals such as portlandite, gypsum and ettringite. Immobilization of B and Cr tends to proceed preferentially under colder conditions. Aging at higher temperatures enhances the leachability of Cr in some CFA samples. Contrary to the behavior of B and Cr, water-soluble F effectively decreases under warmer conditions. PMID:25004853

  6. Fusion reactors for hydrogen production via electrolysis

    International Nuclear Information System (INIS)

    The decreasing availability of fossil fuels emphasizes the need to develop systems which will produce synthetic fuel to substitute for and supplement the natural supply. An important first step in the synthesis of liquid and gaseous fuels is the production of hydrogen. Thermonuclear fusion offers an inexhaustible source of energy for the production of hydrogen from water. Depending on design, electric generation efficiencies of approx. 40 to 60% and hydrogen production efficiencies by high temperature electrolysis of approx. 50 to 70% are projected for fusion reactors using high temperature blankets

  7. Electrolysis of carbon dioxide in Solid Oxide Electrolysis Cells

    DEFF Research Database (Denmark)

    Ebbesen, Sune; Mogensen, Mogens Bjerg

    2009-01-01

    Carbon dioxide electrolysis was studied in Ni/YSZ electrode supported Solid Oxide Electrolysis Cells (SOECs) consisting of a Ni-YSZ support, a Ni-YSZ electrode layer, a YSZ electrolyte, and a LSM-YSZ O2 electrode (YSZ = Yttria Stabilized Zirconia). The results of this study show that long term CO2...... current density and irreversible when operated at conditions that would oxidise carbon. This clearly shows that the passivation was not caused by coke formation. On the other hand, the passivation was partly reversible when introducing hydrogen. The passivation may be a consequence of impurities in the...

  8. Calcium Carbonate Nucleation in an Alkaline Lake Surface Water, Pyramid Lake, Nevada, USA

    Science.gov (United States)

    Reddy, M.M.; Hoch, A.

    2012-01-01

    Calcium concentration and calcite supersaturation (??) needed for calcium carbonate nucleation and crystal growth in Pyramid Lake (PL) surface water were determined during August of 1997, 2000, and 2001. PL surface water has ?? values of 10-16. Notwithstanding high ??, calcium carbonate growth did not occur on aragonite single crystals suspended PL surface water for several months. However, calcium solution addition to PL surface-water samples caused reproducible calcium carbonate mineral nucleation and crystal growth. Mean PL surface-water calcium concentration at nucleation was 2.33 mM (n = 10), a value about nine times higher than the ambient PL surface-water calcium concentration (0.26 mM); mean ?? at nucleation (109 with a standard deviation of 8) is about eight times the PL surface-water ??. Calcium concentration and ?? regulated the calcium carbonate formation in PL nucleation experiments and surface water. Unfiltered samples nucleated at lower ?? than filtered samples. Calcium concentration and ?? at nucleation for experiments in the presence of added particles were within one standard deviation of the mean for all samples. Calcium carbonate formation rates followed a simple rate expression of the form, rate (mM/min) = A (??) + B. The best fit rate equation "Rate (?? mM/?? min) = -0.0026 ?? + 0.0175 (r = 0.904, n = 10)" was statistically significant at greater than the 0.01 confidence level and gives, after rearrangement, ?? at zero rate of 6.7. Nucleation in PL surface water and morphology of calcium carbonate particles formed in PL nucleation experiments and in PL surface-water samples suggest crystal growth inhibition by multiple substances present in PL surface water mediates PL calcium carbonate formation, but there is insufficient information to determine the chemical nature of all inhibitors. ?? 2011 U.S. Government.

  9. Design of a Simple and Cheap Water Electrolyser for the Production of Solar Hydrogen

    OpenAIRE

    R. Prasad

    2009-01-01

    Commercially available conventional alkaline electrolyser and advanced polymer membrane electrolysers for water electrolysis are quite expensive. Taking into account this aspect, a very simple and cheap water electrolyser has been designed and fabricated utilising easily available economical materials for small scale production of hydrogen using renewable energy from photovoltaic panel. The construction details of the electrolyser with a schematic drawing of the experimental set-up for PV pro...

  10. Accurate approach for determining fresh-water carbonate (H2CO3(*)) alkalinity, using a single H3PO4 titration point.

    Science.gov (United States)

    Birnhack, Liat; Sabach, Sara; Lahav, Ori

    2012-10-15

    A new, simple and accurate method is introduced for determining H(2)CO(3)(*) alkalinity in fresh waters dominated by the carbonate weak-acid system. The method relies on a single H(3)PO(4) dosage and two pH readings (acidic pH value target: pH~4.0). The computation algorithm is based on the concept that the overall alkalinity mass of a solution does not change upon the addition of a non-proton-accepting species. The accuracy of the new method was assessed batch-wise with both synthetic and actual tap waters and the results were compared to those obtained from two widely used alkalinity analysis methods (titration to pH~4.5 and the Gran titration method). The experimental results, which were deliberately obtained with simple laboratory equipment (glass buret, general-purpose pH electrode, magnetic stirrer) proved the method to be as accurate as the conventional methods at a wide range of alkalinity values (20-400 mg L(-1) as CaCO(3)). Analysis of the relative error attained in the proposed method as a function of the target (acidic) pH showed that at the range 4.0alkalinity measurement is also described. PMID:23141305

  11. Acid-base balance and hydration status following consumption of mineral-based alkaline bottled water

    Directory of Open Access Journals (Sweden)

    Heil Daniel P

    2010-09-01

    Full Text Available Abstract Background The present study sought to determine whether the consumption of a mineral-rich alkalizing (AK bottled water could improve both acid-base balance and hydration status in young healthy adults under free-living conditions. The AK water contains a naturally high mineral content along with Alka-PlexLiquid™, a dissolved supplement that increases the mineral content and gives the water an alkalizing pH of 10.0. Methods Thirty-eight subjects were matched by gender and self-reported physical activity (SRPA, hrs/week and then split into Control (12 women, 7 men; Mean +/- SD: 23 +/- 2 yrs; 7.2 +/- 3.6 hrs/week SRPA and Experimental (13 women, 6 men; 22 +/- 2 yrs; 6.4 +/- 4.0 hrs/week SRPA groups. The Control group consumed non-mineralized placebo bottled water over a 4-week period while the Experimental group consumed the placebo water during the 1st and 4th weeks and the AK water during the middle 2-week treatment period. Fingertip blood and 24-hour urine samples were collected three times each week for subsequent measures of blood and urine osmolality and pH, as well as total urine volume. Dependent variables were analyzed using multivariate repeated measures ANOVA with post-hoc focused on evaluating changes over time within Control and Experimental groups (alpha = 0.05. Results There were no significant changes in any of the dependent variables for the Control group. The Experimental group, however, showed significant increases in both the blood and urine pH (6.23 to 7.07 and 7.52 to 7.69, respectively, a decreased blood and increased urine osmolality, and a decreased urine output (2.51 to 2.05 L/day, all during the second week of the treatment period (P Conclusions Consumption of AK water was associated with improved acid-base balance (i.e., an alkalization of the blood and urine and hydration status when consumed under free-living conditions. In contrast, subjects who consumed the placebo bottled water showed no changes over the

  12. Surface analysis and depth profiling of corrosion products formed in lead pipes used to supply low alkalinity drinking water.

    Science.gov (United States)

    Davidson, C M; Peters, N J; Britton, A; Brady, L; Gardiner, P H E; Lewis, B D

    2004-01-01

    Modern analytical techniques have been applied to investigate the nature of lead pipe corrosion products formed in pH adjusted, orthophosphate-treated, low alkalinity water, under supply conditions. Depth profiling and surface analysis have been carried out on pipe samples obtained from the water distribution system in Glasgow, Scotland, UK. X-ray diffraction spectrometry identified basic lead carbonate, lead oxide and lead phosphate as the principal components. Scanning electron microscopy/energy-dispersive x-ray spectrometry revealed the crystalline structure within the corrosion product and also showed spatial correlations existed between calcium, iron, lead, oxygen and phosphorus. Elemental profiling, conducted by means of secondary ion mass spectrometry (SIMS) and secondary neutrals mass spectrometry (SNMS) indicated that the corrosion product was not uniform with depth. However, no clear stratification was apparent. Indeed, counts obtained for carbonate, phosphate and oxide were well correlated within the depth range probed by SIMS. SNMS showed relationships existed between carbon, calcium, iron, and phosphorus within the bulk of the scale, as well as at the surface. SIMS imaging confirmed the relationship between calcium and lead and suggested there might also be an association between chloride and phosphorus. PMID:14982163

  13. Adsorption of alkali and alkaline earth radionuclides on zeolite from water solutions

    International Nuclear Information System (INIS)

    The adsorption of cesium and strontium ions from water solutions on zeolite has been investigated in presence of sodium, potassium, magnesium and calcium ions. Distribution ratios of cesium and strontium on the zeolite were determined in solutions of various compositions and solution volume to sorbent weight ratios (batch factor). Breakthrough curves for zeolite layers are reported. (author) 7 refs.; 4 figs

  14. High temperature electrolysis for hydrogen production using nuclear energy

    International Nuclear Information System (INIS)

    High-temperature nuclear reactors have the potential for substantially increasing the efficiency of hydrogen production from water splitting, which can be accomplished via high-temperature electrolysis (HTE) or thermochemical processes. In order to achieve competitive efficiencies, both processes require high-temperature operation (∼850degC). High-temperature electrolytic water splitting supported by nuclear process heat and electricity has the potential to produce hydrogen with overall system efficiencies of 45 to 55%. At the Idaho National Laboratory, we are developing solid-oxide cells to operate in the steam electrolysis mode. The research program includes both experimental and modeling activities. Experimental results were obtained from ten-cell and 22-cell planar electrolysis stacks, fabricated by Ceramatec, Inc. The electrolysis cells are electrolyte-supported, with scandia-stabilized zirconia electrolytes (∼200 μm thick, 64 cm2 active area), nickel-cermet steam/hydrogen electrodes, and manganite air-side electrodes. The metallic interconnect plates are fabricated from ferritic stainless steel. The experiments were performed over a range of steam inlet mole fractions, gas glow rates, and current densities. Hydrogen production rates greater than 100 normal liters per hour for 196 hours have been demonstrated. In order to evaluate the performance of large-scale HTE operations, we have developed single-cell models, based on FLUENT, and a process model, using the systems-analysis code HYSYS. (author)

  15. Phosphate solubilizing bacteria and alkaline phosphatase activity in coastal waters off Trivandrum

    Digital Repository Service at National Institute of Oceanography (India)

    Mamatha, S.S.; Gobika, A.; Janani, P.

    of Oceanography, Dona Paula, Goa. * The paper was presented in the MoES-sponsored National Seminar on Coastal and Island Ecosystems: Conservation and Management at National Institute of Oceanography (NIO), Goa, February 16-17, 2012. Jour. Coast. Env., Vol. 3, No... of heterotrophic and phosphate solubilizing bacteria from Chennai. Southeast coast of India. Indian Journal of Marine Science. 31. 69-72. Siuda, W. 1984. Phosphatases and their role in organic phosphorus transformation in natural waters : A review. Polish...

  16. Water concentrations and hydrogen isotope compositions of alkaline basalt-hosted clinopyroxene megacrysts and amphibole clinopyroxenites: the role of structural hydroxyl groups and molecular water

    Science.gov (United States)

    Kovács, István; Demény, Attila; Czuppon, György; Lécuyer, Christophe; Fourel, Francois; Xia, Qun-Ke; Liu, Jia; Pintér, Zsanett; Király, Edit; Török, Kálmán; Szabó, Ábel; Deloule, Etienne; Falus, György; Fancsik, Tamás; Zajacz, Zoltán; Sándorné Kovács, Judit; Udvardi, Beatrix

    2016-05-01

    The aim of this study was to determine both `water' contents (as OH- and H2O) and δD values of several clinopyroxene samples from alkaline basalts. These parameters were first obtained from five clinopyroxene samples using both the classical `off-line' vacuum extraction technique and the `on-line' high-temperature pyrolysis technique. Blanks measured with the `on-line' gas extraction techniques were low enough to prevent any contamination by atmospheric water vapour. The comparison of data has revealed that our `on-line' procedure is more effective for the extraction of `water' from clinopyroxenes and, consequently, this `on-line' technique was applied to ten additional clinopyroxene samples. Sample δD values cover a similar range from -95 to -45 ‰ (VSMOW) regardless of the studied locations, whereas the total `water' content varies from ~115 to ~2570 ppm. The structural hydroxyl content of clinopyroxene samples measured by micro-FTIR spectrometry varies from ~0 to 476 ppm expressed in molecular water equivalent. The total `water' concentrations determined by mass spectrometry differ considerably from structural hydroxyl contents constrained by micro-FTIR, thus indicating that considerable proportion of the `water' may be present in (nano)-inclusions. The structural hydroxyl concentration—apart from clinopyroxenes separated from amphibole clinopyroxenite xenoliths—correlates positively with the δD values of clinopyroxene megacrysts for each locality, indicating that structurally bond hydrogen in clinopyroxenes may have δD values higher than molecular water in inclusions. This implies that there may be a significant hydrogen isotope fractionation for structural hydroxyl during crystallization of clinopyroxene, while for molecular water there may be no or only negligible isotope fractionation.

  17. An amorphous CoSe film behaves as an active and stable full water-splitting electrocatalyst under strongly alkaline conditions.

    Science.gov (United States)

    Liu, Tingting; Liu, Qian; Asiri, Abdullah M; Luo, Yonglan; Sun, Xuping

    2015-12-01

    It is attractive but still remains a big challenge to develop non-noble metal bifunctional electrocatalysts efficient for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) under alkaline conditions. Herein, an amorphous CoSe film electrodeposited on a Ti mesh (a-CoSe/Ti) is demonstrated to exhibit high electrocatalytic activity and stability for both reactions in 1.0 M KOH. It needs overpotentials of 292 and 121 mV to drive 10 mA cm(-2) for OER and HER, respectively. The two-electrode alkaline water electrolyzer affords a water-splitting current of 10 mA cm(-2) at a cell voltage of 1.65 V. This work offers an attractive cost-effective catalytic material toward full water splitting applications. PMID:26431349

  18. Determination of primary yields in the alpha radiolysis of alkaline water

    International Nuclear Information System (INIS)

    This work presents a fundamental study of the radiolysis of water within the framework of the management of nuclear waste. During their storage, the packages of cemented radioactive waste are likely to release molecular hydrogen. Indeed, interstitial water undergoes decomposition under irradiation. This phenomenon is called radiolysis. In order to envisage the impact of H2 de-gasification on the security of the installations, it is necessary to determine the primary radiolytic yields in the cementing medium (characterised by a pH ranging between 12 and 14), which provides a basic simulations thus allowing us to obtain both the quantities of gas and the pressure in the pore. Such data is currently not available in the literature. Studies were undertaken with a beam of accelerated helium ions in order to reproduce the conditions of irradiation on solutions at pH = 13 in order to determine a first complete series of radiolytic yields.A more complete study was undertaken on the effects of LET and pH on the yield of molecular hydrogen. The results seem to show that the yield of this primary product is little influenced by pH. Such results were in good agreement with those obtained by Monte-Carlo simulations. These studies have shown that, contrary to γ irradiations, the irradiations with α-particles do not lead to the same characteristic times. The extrapolation of this data with respect to the problem of the packaging of nuclear waste is delicate due to the limited amount of results in the literature and also the chemical and physical complexity of the concretes. (author)

  19. Environmental, financial and energy feasibility of the electrolysis of the water steam of a generation IV reactor cooling system during the moments of low consumption ef eletrical energy: challenges and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Stefanelli, Eduardo J.; Vargas, Miltom; Garcia, Pedro L.; Seo, Emilia S.M.; Oliveira, Wagner de S. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: ipen@stefanelli.eng.br

    2009-07-01

    Our civilization is in an inflection moment. Our current decisions will lead us to drastic changes in the planet climate or to cleaner and more sustainable energy generation models. In a certain moment in the evolution of our society, we have privileged the productivity instead of the reasonable use of the planet's resources. This option has been leading us to a situation in which these resources are seriously jeopardized. New models of energy generation and use should be discussed and adopted in order to reverse this process. The electric-power consumption is not constant through time and it must be generated at the moment it is going to be used. There are moments of great idleness in the electric-power generation system, counterbalanced by high demand moments. This characteristic has induced us to the construction of a model of great generation capacity that remains without use most of the time, producing huge financial and environmental impacts. In this article, we discuss the environmental, financial and energy viability of using the idle capacity of the electric-power system to, through water steam electrolysis, produce hydrogen, which would be reconverted into electric power in peak moments by a fuel cell. In this study, we aim at investigating the viability of associating a SOFC (Solid Oxide Fuel Cell), acting as an electrolysis bow, to a generation IV reactor, in order to produce hydrogen from superheated water steam in the cooling of the reactor, which will be converted into electric power via SOFC (Solid Oxide Fuel Cell) in peak moments. The method used in this investigation was to study the electric charge variation consumed in a day, randomly selected in relation to the hour of the day, to launch a curve into a diagram 'Demand x hour of the day', to establish the peak moments, the minimum moments, and the average consumption, and, based on these data and geometrically, predict the viability of using the energetic potential of the moments

  20. Environmental, financial and energy feasibility of the electrolysis of the water steam of a generation IV reactor cooling system during the moments of low consumption ef eletrical energy: challenges and perspectives

    International Nuclear Information System (INIS)

    Our civilization is in an inflection moment. Our current decisions will lead us to drastic changes in the planet climate or to cleaner and more sustainable energy generation models. In a certain moment in the evolution of our society, we have privileged the productivity instead of the reasonable use of the planet's resources. This option has been leading us to a situation in which these resources are seriously jeopardized. New models of energy generation and use should be discussed and adopted in order to reverse this process. The electric-power consumption is not constant through time and it must be generated at the moment it is going to be used. There are moments of great idleness in the electric-power generation system, counterbalanced by high demand moments. This characteristic has induced us to the construction of a model of great generation capacity that remains without use most of the time, producing huge financial and environmental impacts. In this article, we discuss the environmental, financial and energy viability of using the idle capacity of the electric-power system to, through water steam electrolysis, produce hydrogen, which would be reconverted into electric power in peak moments by a fuel cell. In this study, we aim at investigating the viability of associating a SOFC (Solid Oxide Fuel Cell), acting as an electrolysis bow, to a generation IV reactor, in order to produce hydrogen from superheated water steam in the cooling of the reactor, which will be converted into electric power via SOFC (Solid Oxide Fuel Cell) in peak moments. The method used in this investigation was to study the electric charge variation consumed in a day, randomly selected in relation to the hour of the day, to launch a curve into a diagram 'Demand x hour of the day', to establish the peak moments, the minimum moments, and the average consumption, and, based on these data and geometrically, predict the viability of using the energetic potential of the moments in which the

  1. Durability of Solid Oxide Electrolysis Cell and Interconnects for Steam Electrolysis

    DEFF Research Database (Denmark)

    Sun, Xiufu; Chen, Ming; Liu, Yi-Lin; Hendriksen, Peter Vang; Mogensen, Mogens Bjerg

    2013-01-01

    Durability of a solid oxide electrolysis cell tested at -1.5A / cm2 for high temperature steam electrolysis was investigated in the present work under stack relevant conditions. Detailed electrochemical and microstructural analyses were carried out. The results show that both the hydrogen and the...... interconnects on cell degradation under harsh electrolysis conditions is further discussed....

  2. Use of natural mordenite to remove chromium (III) and to neutralize pH of alkaline waste waters.

    Science.gov (United States)

    Córdova-Rodríguez, Valduvina; Rodríguez-Iznaga, Inocente; Acosta-Chávez, Raquel María; Chávez-Rivas, Fernando; Petranovskii, Vitalii; Pestryakov, Alexey

    2016-01-01

    The natural mordenite from Palmarito de Cauto deposit (PZ), Cuba, was studied in this work as an ion exchanger to remove Cr(3+) cations from alkaline aqueous solutions at different pH and chromium concentrations. The mordenite stability under cyclic treatment processes with alkaline solutions and its capacity to decrease the pH of the solutions was also analyzed. It was shown that PZ removes Cr(3+) ions from alkaline solutions, and it happens independently of the starting chromium concentration and the pH of the exchange solution used. This material has an important neutralizing effect on alkaline solutions, expressed in a significant pH decrease from the early stages of the treatments. For solutions with initial pH equal to 11, it decreases to a value of around seven. The stability of this material is not affected significantly after continuous cyclic treatment with NaOH solution, which shows that mordenite, in particular from Palmarito de Cauto deposit, has high stability in alkaline solutions. The results are important as they suggest that natural zeolites may be of interest in treatments of alkaline industrial waste effluents. PMID:26818904

  3. Effect of Substrate Concentration to Anode Chamber Performance in Microbial Electrolysis Cell

    OpenAIRE

    Libertus Darus

    2015-01-01

    Microbial electrolysis is a promising process for bio-hydrogen production which might be implemented in waste water treatment in a near future. Unfortunately substrate could be converted into methane by acetoclastic methanogens and will reduce the coulombic efficiency (CE). The research objective was to study the competition between electrogens and methanogens for substrate in a continuous Microbial Electrolysis Cell (MEC).The competition was studied in relation to controlling acetate influen...

  4. Transient nanobubbles in short-time electrolysis

    Science.gov (United States)

    Svetovoy, Vitaly B.; Sanders, Remco G. P.; Elwenspoek, Miko C.

    2013-05-01

    Water electrolysis in a microsystem is observed and analyzed on a short-time scale of ∼10 μs. The very unusual properties of the process are stressed. An extremely high current density is observed because the process is not limited by the diffusion of electroactive species. The high current is accompanied by a high relative supersaturation, S > 1000, that results in homogeneous nucleation of bubbles. On the short-time scale only nanobubbles can be formed. These nanobubbles densely cover the electrodes and aggregate at a later time to microbubbles. The effect is significantly intensified with a small increase of temperature. Application of alternating polarity voltage pulses produces bubbles containing a mixture of hydrogen and oxygen. Spontaneous reaction between gases is observed for stoichiometric bubbles with sizes smaller than ∼150 nm. Such bubbles disintegrate violently affecting the surfaces of the electrodes.

  5. Further Studies, About New Elements Production, by Electrolysis of Cathodic Pd Thin–Long Wires, in Alcohol-Water Solutions (H, D) and Th-Hg Salts. New Procedures to Produce Pd Nano-Structures

    CERN Document Server

    Celani, F; Righi, E; Trenta, G; Catena, C; D’Agostaro, G; Quercia, P; Andreassi, V; Marini, P; Di Stefano, V; Nakamura, M; Mancini, A; Sona, P G; Fontana, F; Gamberale, L; Garbelli, D; Celia, E; Falcioni, F; Marchesini, M; Novaro, E; Mastromatteo, U

    2005-01-01

    Abstract They were continued, at National Institute of Nuclear Physics, Frascati National Laboratories-Italy, the systematic studies about detection of new elements, some even with isotopic composition different from natural one, after prolonged electrolysis of Pd wires. The electrolytic solution adopted is the, unusual, used from our experimental group since 1999. In short, it was a mixture of both heavy ethyl alcohol (C2H5OD at 90-95%) and water (D2O, at 10-5%), with Th salts at micromolar concentration and Hg at even lower concentration (both of spectroscopic purity). The liquid solutions, before use, were carefully vacuum distilled (and on line 100nm filtered) at low temperatures (30-40°C) and analysed by ICP-MS. The pH was kept quite mild (acidic at about 3-4). The cathode is Pd (99.9% purity) in the shape of long (60cm) and thin wires (diameter only 0.05mm). Before use, it is carefully cleaned and oxidised by Joule heating in air following a (complex) procedure from us continuously improved (since 1995...

  6. The alkaline comet assay used in evaluation of genotoxic damage of drinking water disinfection by-products (bromoform and chloroform

    Directory of Open Access Journals (Sweden)

    Messaouda Khallef

    2015-06-01

    Full Text Available The alkaline comet assay (pH 12.3 is a useful method for monitoring genotoxic effects of environmental pollutants in the root nuclei of Allium cepa and various plants; it allows the detection of single- and double-strand breaks, incomplete excision-repair sites and cross-links. It has been introduced to detect even small changes in DNA structure. It is a technically simple, highly sensitive, fast and economic test which detects in vitro and in vivo genotoxicity (DNA integrity and packing mode in any cell types examined, and requires just a few cells for its execution (Liman et al., 2011; Yıldız et al., 2009. Chloroform and bromoform are the most important trihalomethanes found in drinking water. Different concentrations of bromoform (25, 50, 75and 100µg/ml and chloroform (25, 50, 100 and 200 µg/ml were introduced to onion tuber roots. Distilled water was used as a negative control and methyl methansulfonate (MMS-10 µg/ml as positive control. All obtained data were subjected to statistical analyses by using SPSS 15.0 for Windows software. For comparison purposes, Duncan multiple range tests using one-way analysis of variance (ANOVA were employed and p<0.05 was accepted as the test of significance. Comet assay results showed that DNA damage was significant at p <0.05 for the different concentrations of chloroform and bromoform compared to the negative control which has a damage rate equal to 3.5 ± 0.7 and the positive control which has damage rate equal to 13.5 ± 2.12. The exposure of root tip cells to these disinfection by-products increases DNA damage. All concentrations examined in this study of bromoform and chloroform cause significant harm, which could be due to DNA damage induced by oxidative stress. The measurement of DNA damage in the nuclei of higher plant tissues is a new area of study with SCGE. This assay could be incorporated into in situ monitoring of atmosphere, water and soil: the comet assay allows a fast detection without

  7. Bifunctional enhancement of oxygen reduction reaction activity on Ag catalysts due to water activation on LaMnO3 supports in alkaline media

    Science.gov (United States)

    Park, Shin-Ae; Lee, Eun-Kyung; Song, Hannah; Kim, Yong-Tae

    2015-08-01

    Ag is considered to be one of the best candidates for oxygen reduction reaction electrocatalysts in alkaline media for application in various electrochemical energy devices. In this study, we demonstrate that water activation is a key factor in enhancing the ORR activity in alkaline media, unlike in acid environments. Ag supported on LaMnO3 having a high oxophilicity showed a markedly higher ORR activity than that on carbon with inert surfaces. Through various electrochemical tests, it was revealed that the origin of the enhanced ORR activity of Ag/LaMnO3 is the bifunctional effect mainly due to the water activation at the interface between Ag and LaMnO3. Furthermore, the ligand effect due to the charge transfer from Mn to Ag leads to the enhancement of both oxygen activation on Ag and water activation on Mn sites, and hence, an improvement in the ORR activity of Ag/LaMnO3. On the other hand, the strain effect based on the fine structure variation in the lattice was negligible. We therefore suggest that the employment of a co-catalyst or support with highly oxophilic nature and the maximization of the interface between catalyst and support should be considered in the design of electrocatalysts for the ORR in alkaline media.

  8. Procedure and technique critique for tritium enrichment by electrolysis at the IAEA Laboratory (effective November 1976)

    International Nuclear Information System (INIS)

    This publication gives a detailed description of the experimental and calculation procedures for tritium enrichment. Most descriptive sections are divided into 2 parts: Section A describes the procedure in the IAEA laboratory; section B discusses the reasons behind the various procedures, and may indicate alternative acceptable, or in some cases even better, procedures. The description of the equipment focuses on electrolysis cells, cooling system and power supply. Routine procedures are discussed including handling and checking of samples after receipt, 'spike' and blank water, initial sample distillation, preparation of cells and samples for electrolysis, electrolysis and completion of electrolysis (weighing of cells, neutralisation and distillation) and precautions against contaminations (prevention, detection and cure). A list of equipment required for electrolytic enrichment of tritium is provided

  9. High performance of nitrogen and phosphorus removal in an electrolysis-integrated biofilter.

    Science.gov (United States)

    Gao, Y; Xie, Y W; Zhang, Q; Yu, Y X; Yang, L Y

    2016-01-01

    A novel electrolysis-integrated biofilter system was developed in this study to evaluate the intensified removal of nitrogen and phosphorus from contaminated water. Two laboratory-scale biofilter systems were established, one with electrolysis (E-BF) and one without electrolysis (BF) as control. The dynamics of intensified nitrogen and phosphorus removal and the changes of inflow and outflow water qualities were also evaluated. The total nitrogen (TN) removal rate was 94.4% in our newly developed E-BF, but only 74.7% in the control BF. Ammonium removal rate was up to 95% in biofilters with or without electrolysis integration with an influent ammonium concentration of 40 mg/L, and the accumulation of nitrate and nitrite was much lower in the effluent of E-BF than that of BF. Thus electrolysis plays an important role in TN removal especially the nitrate and nitrite removal. Phosphorus removal was significantly enhanced, exceeding 90% in E-BF by chemical precipitation, physical adsorption, and flocculation of phosphorus because of the in situ formation of ferric ions by the anodizing of sacrificial iron anodes. Results from this study indicate that the electrolysis integrated biofilter is a promising solution for intensified nitrogen and phosphorus removal. PMID:27508376

  10. Steam electrolysis by solid oxide electrolysis cells (SOECs) with proton-conducting oxides

    KAUST Repository

    Bi, Lei

    2014-01-01

    Energy crisis and environmental problems caused by the conventional combustion of fossil fuels boost the development of renewable and sustainable energies. H2 is regarded as a clean fuel for many applications and it also serves as an energy carrier for many renewable energy sources, such as solar and wind power. Among all the technologies for H2 production, steam electrolysis by solid oxide electrolysis cells (SOECs) has attracted much attention due to its high efficiency and low environmental impact, provided that the needed electrical power is generated from renewable sources. However, the deployment of SOECs based on conventional oxygen-ion conductors is limited by several issues, such as high operating temperature, hydrogen purification from water, and electrode stability. To avoid these problems, proton-conducting oxides are proposed as electrolyte materials for SOECs. This review paper provides a broad overview of the research progresses made for proton-conducting SOECs, summarizing the past work and finding the problems for the development of proton-conducting SOECs, as well as pointing out potential development directions.

  11. Steam electrolysis by solid oxide electrolysis cells (SOECs) with proton-conducting oxides.

    Science.gov (United States)

    Bi, Lei; Boulfrad, Samir; Traversa, Enrico

    2014-12-21

    Energy crisis and environmental problems caused by the conventional combustion of fossil fuels boost the development of renewable and sustainable energies. H2 is regarded as a clean fuel for many applications and it also serves as an energy carrier for many renewable energy sources, such as solar and wind power. Among all the technologies for H2 production, steam electrolysis by solid oxide electrolysis cells (SOECs) has attracted much attention due to its high efficiency and low environmental impact, provided that the needed electrical power is generated from renewable sources. However, the deployment of SOECs based on conventional oxygen-ion conductors is limited by several issues, such as high operating temperature, hydrogen purification from water, and electrode stability. To avoid these problems, proton-conducting oxides are proposed as electrolyte materials for SOECs. This review paper provides a broad overview of the research progresses made for proton-conducting SOECs, summarizing the past work and finding the problems for the development of proton-conducting SOECs, as well as pointing out potential development directions. PMID:25134016

  12. RES Hydrogen: efficient pressurised alkaline electrolysers

    DEFF Research Database (Denmark)

    Bowen, Jacob R.; Bentzen, Janet Jonna; Jørgensen, Peter Stanley;

    The RESelyser project addresses issues associated with coupling alkaline electrolysis to renewable energy sources such as electrode stability and gas purity by implementing improved electrodes and a new separator membrane concept. The project aims to improve performance, operation pressure and...... reduce system cost. The project supports DTU Energy's activities on electrodes within the larger FCH-JU project. The overall project demonstrated: improved electrode efficiency also during cyclic operation, safe gas purity at a system pressure of 30 bar, 10 kW stack operation and estimated system costs...

  13. Hydrogen production from fusion reactors coupled with high temperature electrolysis

    International Nuclear Information System (INIS)

    The decreasing availability of fossil fuels emphasizes the need to develop systems which will produce synthetic fuel to substitute for and complement the natural supply. An important first step in the synthesis of liquid and gaseous fuels is the production of hydrogen. Thermonuclear fusion offers an inexhaustible source of energy for the production of hydrogen from water. Processes which may be considered for this purpose include electrolysis, thermochemical decomposition or thermochemical-electrochemical hybrid cycles. Preliminary studies at Brookhaven indicate that high temperature electrolysis has the highest potential efficiency for production of hydrogen from fusion. Depending on design electric generation efficiencies of approximately 40 to 60 percent and hydrogen production efficiencies of approximately 50 to 70 percent are projected for fusion reactors using high temperature blankets

  14. HYFIRE: a tokamak/high-temperature electrolysis system

    International Nuclear Information System (INIS)

    The HYFIRE studies to date have investigated a number of technical approaches for using the thermal energy produced in a high-temperature Tokamak blankets to provide the electrical and thermal energy required to drive a high-temperature (>10000C) water electrolysis process. Current emphasis is on two design points, one consistent with electrolyzer peak inlet temperatures of approx. 13000C, which is an extrapolation of present experience, and one consistent with a peak electrolyzer temperature of 11000C. This latter condition is based on current laboratory experience with high-temperature solid electrolyte fuel cells. Our major conclusion to date is that the technical integration of fusion and high-temperature electrolysis appears to be feasible and that overall hydrogen production efficiencies of 50 to 55% seem possible

  15. HYFIRE: a tokamak/high-temperature electrolysis system

    International Nuclear Information System (INIS)

    The HYFIRE studies to date have investigated a number of technical approaches for using the thermal energy produced in a high-temperature Tokamak blanket to provide the electrical and thermal energy required to drive a high-temperature (> 10000C) water electrolysis process. Current emphasis is on two design points, one consistent with electrolyzer peak inlet temperatures of 14000C, which is an extrapolation of present experience, and one consistent with a peak electrolyzer temperature of 11000C. This latter condition is based on current laboratory experience with high-temperature solid electrolyte fuel cells. Our major conclusion to date is that the technical integration of fusion and high-temperature electrolysis appears to be feasible and that overall hydrogen production efficiencies of 50 to 55% seem possible

  16. Effects of soil water conditions and organic and chemical fertilizers on growth characteristics and water use efficiency of rice in an alkaline non-calcareous soil

    Directory of Open Access Journals (Sweden)

    M. Abbasi

    2012-12-01

    Full Text Available In a greenhouse research, the effects of soil water conditions, sewage sludge and chemical fertilizers on growth characteristics and water use efficiency of rice (Oryza sativa L. cv. Ali Kazemi were studied in a loamy sand alkaline non-calcareous soil. The study was performed as a factorial experiment in a randomized complete blocks design including soil water conditions in three levels (continuous submergence, alternate submergence and alternate saturation and source and amount of organic and chemical fertilizers in 10 levels [control, 100% chemical fertilizers (434.8 mg urea, 66.1 mg KH2PO4, 40 mg KCl, 50 mg FeSO4.7H2O, 38.5 mg FeSO4.7H2O, 21.3 mg ZnSO4.7H2O and 7.9 mg CuSO4.5H2O per kg of soil, 20 g sewage sludge per kg of soil with and without 50% of chemical fertilizers, 40 g sewage sludge per kg of soil with and without 50% of chemical fertilizers, 20 g poultry manure per kg of soil with and without 50% of chemical fertilizers and 40 g poultry manure per kg of soil with and without 50% of chemical fertilizers] with three replications. At the end of growth period, tiller and leaf number per plant, length and diameter of stem, length and volume of roots, and shoot and root dry matter were measured and water use efficiency (WUE was calculated. The results showed that application of 20 and 40 g poultry manure per kg of soil prevented the growth of rice due to increase of soil salinity. Application of 20 and 40 g sewage sludge per kg of soil increased significantly tiller and leaf number per plant, length and diameter of stem, length and volume of roots, shoot and root dry matter and WUE compared to control and 100% chemical fertilizers treatments. Addition of 50% chemical fertilizers to 40 g sewage sludge per kg of soil did not significantly affect tiller and leaf number per plant, stem length, volume of roots, shoot dry matter and WUE of rice. The highest tiller number per plant, stem diameter, root length and the ratio of shoot dry matter to

  17. Imbalances in the hardness/alkalinity ratio of water and Nile tilapia’s growth performance - doi: 10.4025/actascitechnol.v36i1.18995

    Directory of Open Access Journals (Sweden)

    Davi de Holanda Cavalcante

    2014-01-01

    Full Text Available The present work determined the effects of water with unbalanced calcium hardness/total alkalinity (CH/TA ratio on Nile tilapia growth performance. Two unbalanced CH/TA ratios were tested for 8 weeks using one indoor system with 30 circular polyethylene 100 L tanks and one outdoor system with 36 circular polyethylene 250 L tanks. The factors and their specific levels tested were the total alkalinity of water (TA; 50 and 100 mg L-1 CaCO3 and the CH/TA ratio of water (CH/TA; 1/2, 1/1 and 5/1. In the indoor system, the 5/1 CH/TA ratio tanks had higher total ammonia nitrogen (TAN than the 1/2 or 1/1 CH/TA ratio tanks. In the outdoor system, higher concentrations of TAN were found in the 1/2 CH/TA ratio tanks. The soil of the 5/1 CH/TA ratio indoor tanks had higher concentrations of organic carbon than the 1/2 or 1/1 CH/TA ratio tanks. The detrimental effects of the 5/1 CH/TA ratio on fish growth performance were stronger than those associated with the 1/2 CH/TA ratio. A significantly better food conversion ratio was observed in the 1/1 CH/TA ratio outdoor tanks regardless of the TA level of the water.

  18. Polymer anion selective membranes for electrolytic splitting of water. Part I: stability of ion-exchange groups and impact of the polymer binder

    Czech Academy of Sciences Publication Activity Database

    Hnát, J.; Paidar, M.; Schauer, Jan; Žitka, Jan; Bouzek, K.

    2011-01-01

    Roč. 41, č. 9 (2011), s. 1043-1052. ISSN 0021-891X. [International Congress of Chemical and Process Engineering CHISA 2010 /19./ and European Congress of Chemical Engineering ECCE-7 /7./. Praha, 28.08.2010-01.09.2010] R&D Projects: GA MŠk(CZ) 7E08005 Institutional research plan: CEZ:AV0Z40500505 Keywords : water electrolysis * alkaline environment * polymer electrolyte Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.745, year: 2011

  19. A numerical study of the gas-liquid, two-phase flow maldistribution in the anode of a high pressure PEM water electrolysis cell

    DEFF Research Database (Denmark)

    Olesen, Anders Christian; Rømer, Carsten; Kær, Søren Knudsen

    2016-01-01

    causes maldistribution, if land areas of equal width are applied. Moreover, below a water stoichiometry of 350, and at a current density of 1 A/cm2, flow and temperature maldistribution is adversely affected by the presence of the gas phase; particularly gas hold-up near outlet channels can cause...

  20. Mathematical Analysis of High-Temperature Co-electrolysis of CO2 and O2 Production in a Closed-Loop Atmosphere Revitalization System

    Energy Technology Data Exchange (ETDEWEB)

    Michael G. McKellar; Manohar S. Sohal; Lila Mulloth; Bernadette Luna; Morgan B. Abney

    2010-03-01

    NASA has been evaluating two closed-loop atmosphere revitalization architectures based on Sabatier and Bosch carbon dioxide, CO2, reduction technologies. The CO2 and steam, H2O, co-electrolysis process is another option that NASA has investigated. Utilizing recent advances in the fuel cell technology sector, the Idaho National Laboratory, INL, has developed a CO2 and H2O co-electrolysis process to produce oxygen and syngas (carbon monoxide, CO and hydrogen, H2 mixture) for terrestrial (energy production) application. The technology is a combined process that involves steam electrolysis, CO2 electrolysis, and the reverse water gas shift (RWGS) reaction. A number of process models have been developed and analyzed to determine the theoretical power required to recover oxygen, O2, in each case. These models include the current Sabatier and Bosch technologies and combinations of those processes with high-temperature co-electrolysis. The cases of constant CO2 supply and constant O2 production were evaluated. In addition, a process model of the hydrogenation process with co-electrolysis was developed and compared. Sabatier processes require the least amount of energy input per kg of oxygen produced. If co-electrolysis replaces solid polymer electrolyte (SPE) electrolysis within the Sabatier architecture, the power requirement is reduced by over 10%, but only if heat recuperation is used. Sabatier processes, however, require external water to achieve the lower power results. Under conditions of constant incoming carbon dioxide flow, the Sabatier architectures require more power than the other architectures. The Bosch, Boudouard with co-electrolysis, and the hydrogenation with co-electrolysis processes require little or no external water. The Bosch and hydrogenation processes produce water within their reactors, which aids in reducing the power requirement for electrolysis. The Boudouard with co-electrolysis process has a higher electrolysis power requirement because carbon

  1. Suitable alkaline for graphene peeling grown on metallic catalysts using chemical vapor deposition

    Science.gov (United States)

    Karamat, S.; Sonuşen, S.; Çelik, Ü.; Uysallı, Y.; Oral, A.

    2016-04-01

    In chemical vapor deposition, the higher growth temperature roughens the surface of the metal catalyst and a delicate method is necessary for the transfer of graphene from metal catalyst to the desired substrates. In this work, we grow graphene on Pt and Cu foil via ambient pressure chemical vapor deposition (AP-CVD) method and further alkaline water electrolysis was used to peel off graphene from the metallic catalyst. We used different electrolytes i.e., sodium hydroxide (NaOH), potassium hydroxide (KOH), lithium hydroxide (LiOH) and barium hydroxide Ba(OH)2 for electrolysis, hydrogen bubbles evolved at the Pt cathode (graphene/Pt/PMMA stack) and as a result graphene layer peeled off from the substrate without damage. The peeling time for KOH and LiOH was ∼6 min and for NaOH and Ba(OH)2 it was ∼15 min. KOH and LiOH peeled off graphene very efficiently as compared to NaOH and Ba(OH)2 from the Pt electrode. In case of copper, the peeling time is ∼3-5 min. Different characterizations like optical microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy were done to analyze the as grown and transferred graphene samples.

  2. Antimony doped tin oxides and their composites with tin pyrophosphates as catalyst supports for oxygen evolution reaction in proton exchange membrane water electrolysis

    DEFF Research Database (Denmark)

    Xu, Junyuan; Li, Qingfeng; Hansen, Martin Kalmar;

    2012-01-01

    based on tin pyrophosphates as the catalyst support. The materials showed an overall conductivity of 0.57 S cm−1 at 130 °C under the water vapor atmosphere with a contribution of the proton conduction. Using this composite support, iridium oxide nanoparticle catalysts were prepared and characterized in......Proton exchange membrane water electrolysers operating at typically 80 °C or at further elevated temperatures suffer from insufficient catalyst activity and durability. In this work, antimony doped tin oxide nanoparticles were synthesized and further doped with an inorganic proton conducting phase...... sulfuric and phosphoric acid electrolytes, showing much enhanced catalytic activity. Electrolyzer tests were conducted at both 80 °C with an Aquivion™ membrane and at 130 °C with a phosphoric acid doped Aquivion™ membrane. Significant improvement in the anodic kinetics was achieved on the composite...

  3. Tritium-enrichment via CECE-process with high temperature steam electrolysis (HOT ELLY)

    International Nuclear Information System (INIS)

    Aqueous waste which is a by-product of nuclear fuel reprocessing plants, is contaminated with tritium in the form of HTO. This waste must be disposed of in a suitable compact manner. In order to minimize waste volume, tritiated water is enriched by several orders of magnitude of its original concentration. This task is accomplished by using the existing combined electrolysis catalytic exchange (CECE)-Process, which is presently in pilot operation with tritium in a German nuclear research facility (Kernforschungszentrum Karlsruhe, KfK, FRG). Substantial energy reduction can be achieved by substituting the conventional water electrolysis by high-temperature steam electrolysis (HOT ELLY) for separating tritiated water into its components

  4. Researches on the electrolysis of metal oxides dissolved in boric anhydride or in melt borates. New methods of preparation of amorphous boron, borides and some metals

    International Nuclear Information System (INIS)

    This research thesis reports the investigation of the electrolysis of alkaline borates, alkaline earth borates and magnesium borate, and the investigation of mixtures containing a metal oxide dissolved in a bath formed by a tetraborate and a fluoride. The author more particularly studies the chemical products separated at the cathode level, i.e. boron (more or less pure), borates and other metals (zinc, tungsten, molybdenum)

  5. Titanium metal obtention by fused salts electrolysis

    International Nuclear Information System (INIS)

    Potassium fluorotitanate dissolved in fused sodium chloride or potassium chloride may be electrolyzed under an inert gas atmosphere. Solid electrolysis products are formed on the cathode which contains titanium metal, sodium chloride, lower fluorotitanates and small quantities of alkali metal fluorotitanate. The extraction of titanium from the electrolysis products may be carried out by aqueous leaching (removal of chloride salts of alkali metals and a certain amount of fluorotitanates). Titanium metal obtained is relatively pure. (Author)

  6. High-resolution Imaging of pH in Alkaline Sediments and Water Based on a New Rapid Response Fluorescent Planar Optode

    Science.gov (United States)

    Han, Chao; Yao, Lei; Xu, Di; Xie, Xianchuan; Zhang, Chaosheng

    2016-05-01

    A new dual-lumophore optical sensor combined with a robust RGB referencing method was developed for two-dimensional (2D) pH imaging in alkaline sediments and water. The pH sensor film consisted of a proton-permeable polymer (PVC) in which two dyes with different pH sensitivities and emission colors: (1) chloro phenyl imino propenyl aniline (CPIPA) and (2) the coumarin dye Macrolex® fluorescence yellow 10 GN (MFY-10 GN) were entrapped. Calibration experiments revealed the typical sigmoid function and temperature dependencies. This sensor featured high sensitivity and fast response over the alkaline working ranges from pH 7.5 to pH 10.5. Cross-sensitivity towards ionic strength (IS) was found to be negligible for freshwater when IS sensor had a spatial resolution of approximately 22 μm and aresponse time of sensor was demonstrated using the pH microelectrode. An example of pH image obtained in the natrual freshwater sediment and water associated with the photosynthesis of Vallisneria spiral species was also presented, suggesting that the sensor held great promise for the field applications.

  7. Electrolysis byproduct D2O provides a third way to mitigate CO2

    International Nuclear Information System (INIS)

    Rapid atomic power deployment may be possible without using fast breeder reactors or making undue demands on uranium resource. Using by-product D2O and thorium-U233 in CANDU and RBMK piles may circumvent need for either fast breeder reactors or seawater uranium. Atmospheric CO2 is presently increasing 2.25%/year in proportion to 2.25%/year exponential fossil fuel consumption increase. Roughly 1/3 anthropologic CO2 is removed by various CO2 sinks. CO2 removal is modelled as being proportional to 45-year-earlier CO2 amount above 280 ppm-C Water electrolysis produces roughly 0.1 kg-D20/kWe-y. Material balance assumes each electrolysis stage increases D2O bottoms concentration times 3. Except for first two electrolysis stages, all water from hydrogen consumption is returned to electrolysis. The unique characteristic of this process is the ability to economically burn all deuterium-enriched H2 in vehicles. Condensate from vehicles returns to appropriate electrolysis stage. Fuel cell condensate originally from reformed natural gas may augment second-sage feed. Atomic power expansion is 5%/year, giving 55000 GWe by 2100. World primary energy increases 2.25%/y, exceeding 4000 EJ/y by 2100. CO2 maximum is roughly 600 ppm-C around year 2085. CO2 declines back below 300 ppm-C by 2145 if the 45-year-delay seawater sink remains effective

  8. A Control Strategy for Photovoltaic-Solid Polymer Electrolysis System Based on Surface Temperature of PV Panel

    OpenAIRE

    Riza Muhida; Wahyudi; Rifki Muhida; Ahmad U. Priantoro

    2008-01-01

    Processes to produce hydrogen from solar photovoltaic powered water electrolysis using solid polymer electrolysis are reported. An alternative control of maximum power point tracking method based on analysis of PV panels surface Temperature for the PV-SPE system was designed and implemented. From this analysis an optimal voltage of PV can be obtained and was realized as a reference voltage of Dc-DC converter. By maintenance the output voltage of PV using the reference voltage control, the out...

  9. A modelling exercise on the importance of ternary alkaline earth carbonate species of uranium(VI) in the inorganic speciation of natural waters

    International Nuclear Information System (INIS)

    Highlights: • The U(VI) speciation in natural waters has been modelled through a modelling exercise. • The results evidence the importance of alkaline earth U(VI) carbonate complexes. • Possible solubility-controlling phases were reported and discussed. • The differences were related to the choice and reliability of thermodynamic data. • Databases need to be improved for reliable U(VI) speciation calculations. - Abstract: Predictive modelling of uranium speciation in natural waters can be achieved using equilibrium thermodynamic data and adequate speciation software. The reliability of such calculations is highly dependent on the equilibrium reactions that are considered as entry data, and the values chosen for the equilibrium constants. The working group “Speciation” of the CETAMA (Analytical methods establishment committee of the French Atomic Energy commission, CEA) has organized a modelling exercise, including four participants, in order to compare modellers’ selections of data and test thermodynamic data bases regarding the calculation of U(VI) inorganic speciation. Six different compositions of model waters were chosen so that to check the importance of ternary alkaline earth carbonate species of U(VI) on the aqueous speciation, and the possible uranium solid phases as solubility-limiting phases. The comparison of the results from the participants suggests (i) that it would be highly valuable for end-users to review thermodynamic constants of ternary carbonate species of U(VI) in a consistent way and implement them in available speciation data bases, and (ii) stresses the necessary care when using data bases to avoid biases and possible erroneous calculations

  10. Improving performance of catalysts for water electrolysis

    DEFF Research Database (Denmark)

    Frydendal, Rasmus

    This Ph.D. thesis presents work on non-noble metal oxide catalysts for the oxygen evolution reaction, OER. This reaction is currently a bottleneck in electrolyzer technologies, which are promising for energy storage purposes. In particular, Polymer Electrolyte Membrane, PEM, cells are attractive...

  11. The effects of surface treatment and stannate as an electrolyte additive on the corrosion and electrochemical performances of pure aluminum in an alkaline methanol-water solution

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, X.X. [Department of Chemistry, Zhejiang University, Zheda Road 38, Hangzhou 310027, Zhejiang (China); Wang, J.M., E-mail: wjm@zju.edu.cn [Department of Chemistry, Zhejiang University, Zheda Road 38, Hangzhou 310027, Zhejiang (China); Wang, Q.L.; Kong, D.S.; Shao, H.B. [Department of Chemistry, Zhejiang University, Zheda Road 38, Hangzhou 310027, Zhejiang (China); Zhang, J.Q.; Cao, C.N. [Department of Chemistry, Zhejiang University, Zheda Road 38, Hangzhou 310027, Zhejiang (China); State Key Laboratory for Corrosion and Protection of Metal, Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Road, Shenyang 110016 (China)

    2010-06-01

    Pure aluminum electrodes were treated in alkaline stannate solutions, and the effects of some factors such as NaOH content and treating time were explored. The corrosion and electrochemical performances of the modified aluminum anodes in 4.0 M KOH methanol-water mixed solutions containing a methanol/water volume ratio of 7:3 (30% water) with and without stannate were investigated by means of hydrogen collection, polarization curve, galvanostatic discharge, scanning electron microscopy (SEM), and energy dispersive analysis of X-ray (EDAX). Metallic tin with high hydrogen evolution overpotential was deposited in aluminum surfaces by the modification treatments using stannate, resulting in the relatively low corrosion rate and markedly enhanced discharge performance of the modified aluminum anodes. In our experimental range the aluminum electrode treated in the solution with 0.1 M NaOH for 30 min showed lower corrosion rate and better discharge performance. The addition of Na{sub 2}SnO{sub 3} in 4.0 M KOH methanol-water mixed solutions with 30% water inhibited the corrosion of the aluminum electrodes modified in the treating solution with 0.1 M NaOH for 30 min, resulting from the deposition of tin with high hydrogen evolution overpotential in aluminum surfaces. The deposition of metallic tin on the electrode surface and the existence of stannate in the electrolytes were responsible for the notable enhancement in the discharge performance of the modified aluminum anode.

  12. A Study of Gas Diffusion Electrodes for the Coupled Reaction of Water Electrolysis and Electrocatalytic Benzene Hydrogenation%电催化苯加氢与水电解耦合反应的气体扩散电极研究

    Institute of Scientific and Technical Information of China (English)

    黄海燕; 俞英; 王晶

    2005-01-01

    Gas diffusion electrodes are applied to the coupled reaction of water electrolysis and electrocatalytic benzene hydrogenation. The effects of the preparation conditions of electrodes, electrolyte acidity, the concentration of benzene and water vapor, and the flow rate of N2 are investigated by evaluating the efficiency of the current. Furthermore, the optimal operational conditions have been ascertained. The results of our experiment show that gas diffusion electrodes have good performance when the content of PTFE is 10% (wt) and that of Nafion is 0.75mg/cm2. The optimal operational conditions are as follows: The temperature of electrolysis is 70℃, acidity 0.5mol/L, the concentration of benzene 26%,the concentration of vapor 10%, the flow rate of N2 80mL/min-240mL/min. The efficiency of the current can reach 35%under optimal operational conditions. Then, a conclusion can be drawn that gas diffusion electrodes can improve the rate of the coupled reaction effectively.

  13. 2-Acrylamido-2-methyl-1-propanesulfonic Acid Grafted Poly(vinylidene fluoride-co-hexafluoropropylene)-Based Acid-/Oxidative-Resistant Cation Exchange for Membrane Electrolysis.

    Science.gov (United States)

    Pandey, Ravi P; Das, Arindam K; Shahi, Vinod K

    2015-12-30

    For developing acid-/oxidative-resistant aliphatic-polymer-based cation-exchange membrane (CEM), macromolecular modification of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) was carried out by controlled chemical grafting of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS). To introduce the unsaturation suitable for chemical grafting, dehydrofluorination of commercially available PVDF-co-HFP was achieved under alkaline medium. Sulfonated copolymer (SCP) was prepared by the free radical copolymerization of dehydofluorinated PVDF-co-HFP (DHPVDF-co-HFP) and AMPS in the presence of free radical initiator. Prepared SCP-based CEMs were analyzed for their morphological characteristics, ion-exchange capacity (IEC), water uptake, conductivity, and stabilities (mechanical, chemical, and thermal) in comparison with state-of-art Nafion117 membrane. High bound water content avoids the membrane dehydration, and most optimal (SCP-1.33) membrane exhibited about ∼2.5-fold high bound water content in comparison with that of Nafion117 membrane. Bunsen reaction of iodine-sulfur (I-S) was successfully performed by direct-contact-mode membrane electrolysis in a two-compartment electrolytic cell using different SCP membranes. High current efficiency (83-99%) confirmed absence of any side reaction and 328.05 kJ mol-H2(-1) energy was required for to produce 1 mol of H2 by electrolytic cell with SCP-1.33 membrane. In spite of low conductivity for reported SCP membrane in comparison with that of Nafion117 membrane, SCP-1.33 membrane was assessed as suitable candidate for electrolysis because of its low-cost nature and excellent stabilities in highly acidic environment may be due to partial fluorinated segments in the membrane structure. PMID:26642107

  14. Elimination of heavy metals from leachates by membrane electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, R. [Technische Universitaet Dresden, Institut fuer Siedlungs- und Industriewasserwirtschaft, Mommsenstrasse 13, 01062 Dresden (Germany); Seidel, H. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Department Bioremediation, Permoserstrasse 15, D-04318 Leipzig (Germany); Rahner, D. [Technische Universitaet Dresden, Institut fuer Physikalische Chemie und Eektrochemie, Mommsenstrasse 13, D-01062 Dresden (Germany); Morgenstern, P. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Department Analytik, Permoserstrasse 15, D-04318 Leipzig (Germany); Loeser, C. [Technische Universitaet Dresden, Institut fuer Lebensmittel- und Bioverfahrenstechnik, Bergstrasse 120, D-01062 Dresden (Germany)

    2004-10-01

    The elimination of heavy metals from bioleaching process waters (leachates) by electrolysis was studied in the anode and cathode region of a membrane electrolysis cell at current densities of 5-20 mA/cm{sup 2} using various electrode materials. The leaching waters containing a wide range of dissolved heavy metals, were high in sulfate, and had pH values of approx. 3. In preliminary tests using a rotating disc electrode the current density-potential curve (CPK) was recorded at a rotation velocity of 0, 1000 and 2000 rpm and a scan rate of 10 mV/s in order to collect information on the influence of transport processes on the electrochemical processes taking place at the electrodes. The electrochemical deposition-dissolution processes at the cathode are strongly dependent on the hydrodynamics. Detailed examination of the anodic oxidation of dissolved Mn(II) indicated that the manganese dioxide which formed adhered well to the electrode surface but in the cathodic return run it was again reduced. Electrode pairs of high-grade steel, lead and coal as well as material combinations were used to investigate heavy metal elimination in a membrane electrolysis cell. Using high-grade steel, lead and carbon electrode pairs, the reduction and deposition of Cu, Zn, Cr, Ni and some Cd in metallic or hydroxide form were observed in an order of 10-40 % in the cathode chamber. The dominant process in the anode chamber was the precipitation of manganese dioxide owing to the oxidation of dissolved Mn(II). Large amounts of heavy metals were co-precipitated by adsorption onto the insoluble MnO{sub 2}. High-grade steel and to some extent lead anodes were dissolved and hence were proven unsuitable as an anode material. These findings were largely confirmed by experiments using combination electrodes of coal and platinized titanium as an anode material and steel as a cathode material.The results indicate that electrochemical metal separation in the membrane electrolysis cell can represent a

  15. The Technological Improvements of Aluminum Alloy Coloring by Electrolysis

    Institute of Scientific and Technical Information of China (English)

    LI Nai-jun

    2004-01-01

    The technological process of coloring golden-tawny on aluminum alloy by electrolysis was improved in this paper. The optimum composition of electrolyte was found, the conditions of deposition and anodic oxidation by electrolysis were studied. The oxidative membrane on aluminum alloy was satisfying, the colored aluminum alloy by electrolysis is uniformity,bright and beautiful, and the coloring by electrolysis is convenient and no pollution.

  16. Microbial Electrolysis Cells for High Yield Hydrogen Gas Production from Organic Matter

    KAUST Repository

    Logan, Bruce E.

    2008-12-01

    The use of electrochemically active bacteria to break down organic matter, combined with the addition of a small voltage (>0.2 V in practice) in specially designed microbial electrolysis cells (MECs), can result in a high yield of hydrogen gas. While microbial electrolysis was invented only a few years ago, rapid developments have led to hydrogen yields approaching 100%, energy yields based on electrical energy input many times greater than that possible by water electrolysis, and increased gas production rates. MECs used to make hydrogen gas are similar in design to microbial fuel cells (MFCs) that produce electricity, but there are important differences in architecture and analytical methods used to evaluate performance. We review here the materials, architectures, performance, and energy efficiencies of these MEC systems that show promise as a method for renewable and sustainable energy production, and wastewater treatment. © 2008 American Chemical Society.

  17. Poisoning of Solid Oxide Electrolysis Cells by Impurities

    DEFF Research Database (Denmark)

    Ebbesen, Sune; Graves, Christopher R.; Hauch, Anne;

    2010-01-01

    Electrolysis of H2O, CO2, and co-electrolysis of H2O and CO2 was studied in Ni/yttria-stabilized zirconia (YSZ) electrode supported solid oxide electrolysis cells (SOECs) consisting of a Ni/YSZ support, a Ni/YSZ electrode layer, a YSZ electrolyte, and an lanthanum strontium manganite (LSM)/YSZ ox...

  18. 21 CFR 886.4250 - Ophthalmic electrolysis unit.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic electrolysis unit. 886.4250 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4250 Ophthalmic electrolysis unit. (a) Identification. An ophthalmic electrolysis unit is an AC-powered or battery-powered device intended to...

  19. Anomalous isotopic distribution of elements deposited on palladium induced by cathodic electrolysis

    International Nuclear Information System (INIS)

    It was confirmed by several analytic methods that reaction products with atomic number ranging from 20 to 28, 46 to 54, and 72 to 82 are detected in palladium cathodes subjected to electrolysis in a heavy water solution at high pressure, high temperature and by high current density for one month. Isotopic distributions were radically different from the natural ones. (author)

  20. Strong-Coupled Cobalt Borate Nanosheets/Graphene Hybrid as Electrocatalyst for Water Oxidation Under Both Alkaline and Neutral Conditions.

    Science.gov (United States)

    Chen, Pengzuo; Xu, Kun; Zhou, Tianpei; Tong, Yun; Wu, Junchi; Cheng, Han; Lu, Xiuli; Ding, Hui; Wu, Changzheng; Xie, Yi

    2016-02-12

    Developing highly active catalysts for the oxygen evolution reaction (OER) is of paramount importance for designing various renewable energy storage and conversion devices. Herein, we report the synthesis of a category of Co-Pi analogue, namely cobalt-based borate (Co-Bi ) ultrathin nanosheets/graphene hybrid by a room-temperature synthesis approach. Benefiting from the high surface active sites exposure yield, enhanced electron transfer capacity, and strong synergetic coupled effect, this Co-Bi NS/G hybrid shows high catalytic activity with current density of 10 mA cm(-2) at overpotential of 290 mV and Tafel slope of 53 mV dec(-1) in alkaline medium. Moreover, Co-Bi NS/G electrocatalysts also exhibit promising performance under neutral conditions, with a low onset potential of 235 mV and high current density of 14.4 mA cm(-2) at 1.8 V, which is the best OER performance among well-developed Co-based OER electrocatalysts to date. Our finding paves a way to develop highly active OER electrocatalysts. PMID:26757358

  1. Geochemical modelling of arsenic and selenium leaching in alkaline water treatment sludge from the production of non-ferrous metals.

    Science.gov (United States)

    Cornelis, Geert; Poppe, Sofie; Van Gerven, Tom; Van den Broeck, Eric; Ceulemans, Michiel; Vandecasteele, Carlo

    2008-11-30

    Geochemical modelling of leaching of oxyanion forming elements such as arsenic (As) and selenium (Se) is frequently not successful. A consistent thermodynamic dataset of As and Se was therefore composed, not only including precipitation, but also adsorption and solid solution, and was applied to the pH-dependent leaching behaviour of As and Se in an alkaline residue with a pH 11.1 from the lime treatment of sulphuric acid wastewaters from the production of non-ferrous metals. The As and Se content ranged up to 6.7 wt% and 0.29 wt%, respectively and speciation analysis showed that 96.3% of As occured as arsenate whereas Se speciation comprised 79% selenate and 21.0% selenite. XRD and SEM/EDX analysis showed that arsenate occurred as rauenthalite (Ca(3)(AsO(4))(2).10H(2)O), associated with gypsum, the most important mineral. Arsenate and arsenite concentrations were only slightly below equilibrium with rauenthalite and calciumarsenite (CaHAsO(3)), respectively and consideration of adsorption and solid solution only marginally improved model predictions. Selenate (Se(VI)) and selenite (Se(IV)), on the other hand, were far from equilibrium with their corresponding calcium metalate. The application of solid solutions and adsorption of Se(VI) and Se(IV) oxyanions with gypsum, calcite and ettringite significantly improved model predictions but missing thermodynamic data and especially the lack of a comprehensive model for solid solution and surface exchange with calcite and ettringite still hampered efficient modelling. PMID:18387734

  2. Electrochemical extraction of oxygen using PEM electrolysis technology

    Directory of Open Access Journals (Sweden)

    BOULBABA ELADEB

    2012-11-01

    Full Text Available Electrochemical extraction of oxygen from air can be carried out by chemical reduction of oxygen at the cathode and simultaneous oxygen evolution by water anode oxidation. The present investigation deals with the use of an electrolysis cell of PEM technology for this purpose. A dedicated 25 cm2 cell provided with a commercial water electrolysis MEA and titanium grooved plates has been designed for continuous operation at pressures close to the ambient level. The MEA consisted of a Nafion 117 membrane sandwiched between a Pt/C cathode and a non-supported Pt-Ir anode. Oxygen partial consumption in long-term runs was evaluated by analysis of the outlet air by gas chromatography, depending on the cell voltage - or the current density - and the excess in air oxygen fed to the cathode. Runs over more 50 hours indicated the relative stability of the components used for current densities ranging from 0.1 to 0.2 A cm-2 with high efficiency of oxygen reduction. Higher current density could be envisaged with more efficient MEA’s, exhibiting lower overpotentials for oxygen evolution to avoid too significant degradation of the anode material and the membrane. Interpretation of the data has been carried out by calculation of the cathode current efficiency.

  3. Effect of water soluble extract of nacre (Pinctada maxima) on alkaline phosphatase activity and Bcl-2 expression in primary cultured osteoblasts from neonatal rat calvaria.

    Science.gov (United States)

    Moutahir-Belqasmi, F; Balmain, N; Lieberrher, M; Borzeix, S; Berland, S; Barthelemy, M; Peduzzi, J; Milet, C; Lopez, E

    2001-01-01

    The nacre (mother of pearl) layer of the oyster Pinctada maxima shell can initiate bone formation by human osteoblasts in vivo and in vitro and is a new biomaterial that induces osteogenesis. This activity of nacre could be due to its water-soluble matrix. We examined the action of a water-soluble extract of nacre on the osteoblast phenotype of cells isolated from rat neonatal calvaria by measuring alkaline phosphatase (ALP) activity and by localization of the anti-apoptotic protein Bcl-2 by immunocytochemistry. ALP activity was increased 7% (pproduction in osteoblasts, that is correlated with the cell cycle. Bcl-2 was also abundant in the nucleoli of extract-treated cells. Thus, the concentration and subcellular distribution of Bcl-2 in osteoblasts in primary cultures is influenced by nacre extract, and related to the cell cycle and the regulation of gene expression. Hence, knowledge of how water-soluble extracts of Pinctada maxima nacre act on osteoblasts in vitro may reveal the mechanisms involved in its action in vivo on bone cells and bone regeneration. PMID:15348370

  4. Silica in alkaline brines

    Science.gov (United States)

    Jones, B.F.; Rettig, S.L.; Eugster, H.P.

    1967-01-01

    Analysis of sodium carbonate-bicarbonate brines from closed basins in volcanic terranes of Oregon and Kenya reveals silica contents of up to 2700 parts per million at pH's higher than 10. These high concentrations of SiO 2 can be attributed to reaction of waters with silicates, and subsequent evaporative concentration accompanied by a rise in pH. Supersaturation with respect to amorphous silica may occur and persist for brines that are out of contact with silicate muds and undersaturated with respect to trona; correlation of SiO2 with concentration of Na and total CO2 support this interpretation. Addition of moredilute waters to alkaline brines may lower the pH and cause inorganic precipitation of substantial amounts of silica.

  5. Study of hydride precipitation on zircaloy-4 by electrolysis process

    International Nuclear Information System (INIS)

    It had been conducted the hydration of zircaloy-4 by electrolysis in sulphuric acid electrolyte. In this experiment hydrogen in the from of atoms and ion is produced from electrolysis in a dilute sulphuric acid. The hydrogen is liberated in the vicinity of the cathode and the specimen itself was as the cathode. Electrolysis was performed at the current of 10 amperes and the potential of 30 volts. In this potential the affinity of zirconium increases and it is reactive enough to absorb hydrogen, which is close to the cathode. The absorbed hydrogen dissolves through the zircaloy-4. The hydrogenated specimens were heated at temperature 400 oC in inert atmosphere. Furthermore, the specimens were cooled in the furnace by the appropriate furnace cooling. The optical microscope was used for performing the metallographical analysis. The specimens were etched with solution of 25 ml 30% H2O2, 25 ml 70% HNO3 and 10 drops of 48% HF by swabbing technique for 10-20 seconds and washed by water. Based on ASTM 353 at 100x magnification the length of platelets is not less than 1.5 mm. From the microstructure image, hydride platelets have improperly been found, because part of them is in the particle from with diameter in the range of 1.4-7 micron meters which is uniformly distributed in the materials. The particle density is in the range of 13-36 particles per 3.5 mm2 of the material surface. The platelet orientation is not parallel to the rolling direction. This fact indicated that the basal plane of zircaloy-4 crystals is not paral let to the rolling direction

  6. In situ generation of steam and alkaline surfactant for enhanced oil recovery using an exothermic water reactant (EWR)

    Science.gov (United States)

    Robertson, Eric P

    2011-05-24

    A method for oil recovery whereby an exothermic water reactant (EWR) encapsulated in a water soluble coating is placed in water and pumped into one or more oil wells in contact with an oil bearing formation. After the water carries the EWR to the bottom of the injection well, the water soluble coating dissolves and the EWR reacts with the water to produce heat, an alkali solution, and hydrogen. The heat from the EWR reaction generates steam, which is forced into the oil bearing formation where it condenses and transfers heat to the oil, elevating its temperature and decreasing the viscosity of the oil. The aqueous alkali solution mixes with the oil in the oil bearing formation and forms a surfactant that reduces the interfacial tension between the oil and water. The hydrogen may be used to react with the oil at these elevated temperatures to form lighter molecules, thus upgrading to a certain extent the oil in situ. As a result, the oil can flow more efficiently and easily through the oil bearing formation towards and into one or more production wells.

  7. Fabrication of nanostructures by plasma electrolysis

    CERN Document Server

    Aliofkhazraei, Mahmood

    2011-01-01

    In this handbook and ready reference, the authors introduce the concept of plasma electrolysis, explaining how the coatings are characterized and discussing their mechanical and corrosion properties. They then go on to look at specific industrial applications of this powerful and low-cost method, including aerospace, the biomaterials industry as well as in the oil and gas industry.

  8. Additional considerations on electrolysis in electromembrane extraction

    Czech Academy of Sciences Publication Activity Database

    Šlampová, Andrea; Kubáň, Pavel; Boček, Petr

    2016-01-01

    Roč. 1429, JAN (2016), s. 364-368. ISSN 0021-9673 R&D Projects: GA ČR(CZ) GA13-05762S Institutional support: RVO:68081715 Keywords : electrolysis * electromembrane extraction * extraction recovery and quantity Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.169, year: 2014

  9. H2O/CO2 co-electrolysis in solid oxide electrolysis cells

    Institute of Scientific and Technical Information of China (English)

    Han Minfang; Fan Hui; Peng Suping

    2014-01-01

    A solid oxide electrolysis cell (SOEC) is an environmental-friendly device which can convert electric energy into chemical energy with high efficiency. In this paper,the progress on structure and operational princi-ple of an SOEC for co-electrolyzing H2O and CO2 to generate syngas was reviewed. The recent development of high temperature H2O/CO2 co-electrolysis from solid oxide single electrolysis cell was introduced. Also investi-gated was H2O/CO2 co-electrolysis research using hydrogen electrode-supported nickel (Ni)-yttria-stabilized zir-conia (YSZ)/YSZ/Sr-doped LaMnO3 (LSM)-YSZ cells in our group. With 50%H2O,15.6%H2 and 34.4%CO2 inlet gas to Ni-YSZ electrode,polarization curves (I-U curves) and electrochemical impedance spectra (EIS) were measured at 800℃and 900℃. Long-term durability of electrolysis was carried out with the same in-let gas at 900℃and 0.2 A/cm2. In addition,the improvement of structure and development of novel materials for increasing the electrolysis efficiency of SOECs were put forward as well.

  10. ALP (Alkaline Phosphatase) Test

    Science.gov (United States)

    ... Also known as: ALK PHOS; Alkp Formal name: Alkaline Phosphatase Related tests: AST ; ALT ; GGT ; Bilirubin ; Liver Panel ; Bone Markers ; Alkaline Phosphatase Isoenzymes; Bone Specific ALP All content on ...

  11. LARGE-SCALE HYDROGEN PRODUCTION FROM NUCLEAR ENERGY USING HIGH TEMPERATURE ELECTROLYSIS

    International Nuclear Information System (INIS)

    Hydrogen can be produced from water splitting with relatively high efficiency using high-temperature electrolysis. This technology makes use of solid-oxide cells, running in the electrolysis mode to produce hydrogen from steam, while consuming electricity and high-temperature process heat. When coupled to an advanced high temperature nuclear reactor, the overall thermal-to-hydrogen efficiency for high-temperature electrolysis can be as high as 50%, which is about double the overall efficiency of conventional low-temperature electrolysis. Current large-scale hydrogen production is based almost exclusively on steam reforming of methane, a method that consumes a precious fossil fuel while emitting carbon dioxide to the atmosphere. Demand for hydrogen is increasing rapidly for refining of increasingly low-grade petroleum resources, such as the Athabasca oil sands and for ammonia-based fertilizer production. Large quantities of hydrogen are also required for carbon-efficient conversion of biomass to liquid fuels. With supplemental nuclear hydrogen, almost all of the carbon in the biomass can be converted to liquid fuels in a nearly carbon-neutral fashion. Ultimately, hydrogen may be employed as a direct transportation fuel in a 'hydrogen economy.' The large quantity of hydrogen that would be required for this concept should be produced without consuming fossil fuels or emitting greenhouse gases. An overview of the high-temperature electrolysis technology will be presented, including basic theory, modeling, and experimental activities. Modeling activities include both computational fluid dynamics and large-scale systems analysis. We have also demonstrated high-temperature electrolysis in our laboratory at the 15 kW scale, achieving a hydrogen production rate in excess of 5500 L/hr.

  12. LARGE-SCALE HYDROGEN PRODUCTION FROM NUCLEAR ENERGY USING HIGH TEMPERATURE ELECTROLYSIS

    Energy Technology Data Exchange (ETDEWEB)

    James E. O' Brien

    2010-08-01

    Hydrogen can be produced from water splitting with relatively high efficiency using high-temperature electrolysis. This technology makes use of solid-oxide cells, running in the electrolysis mode to produce hydrogen from steam, while consuming electricity and high-temperature process heat. When coupled to an advanced high temperature nuclear reactor, the overall thermal-to-hydrogen efficiency for high-temperature electrolysis can be as high as 50%, which is about double the overall efficiency of conventional low-temperature electrolysis. Current large-scale hydrogen production is based almost exclusively on steam reforming of methane, a method that consumes a precious fossil fuel while emitting carbon dioxide to the atmosphere. Demand for hydrogen is increasing rapidly for refining of increasingly low-grade petroleum resources, such as the Athabasca oil sands and for ammonia-based fertilizer production. Large quantities of hydrogen are also required for carbon-efficient conversion of biomass to liquid fuels. With supplemental nuclear hydrogen, almost all of the carbon in the biomass can be converted to liquid fuels in a nearly carbon-neutral fashion. Ultimately, hydrogen may be employed as a direct transportation fuel in a “hydrogen economy.” The large quantity of hydrogen that would be required for this concept should be produced without consuming fossil fuels or emitting greenhouse gases. An overview of the high-temperature electrolysis technology will be presented, including basic theory, modeling, and experimental activities. Modeling activities include both computational fluid dynamics and large-scale systems analysis. We have also demonstrated high-temperature electrolysis in our laboratory at the 15 kW scale, achieving a hydrogen production rate in excess of 5500 L/hr.

  13. Effects of alkalinity on membrane bioreactors for reject water treatment: Performance improvement, fouling mitigation and microbial structures.

    Science.gov (United States)

    Hu, Dalong; Zhou, Zhen; Shen, Xuelian; Wei, Haijuan; Jiang, Lu-Man; Lv, Yan

    2015-12-01

    Two submerged membrane bioreactors (MBRs) for reject water treatment were operated to investigate effects of sodium bicarbonate (SB) addition on enhancing process performance and mitigating membrane fouling. Results showed that SB addition enhanced average removal efficiencies of COD and NH4-N by 14.6% and 38.3%, respectively. With SB addition, the extracellular polymeric substances (EPS) content in activated sludge increased, but those in membrane foulants greatly decreased. Gel permeation chromatography analysis demonstrated that EPS in MBRs for reject water treatment had much larger molecular weight (MW) and broader MW distribution than those in MBRs for municipal wastewater treatment. The fouling mitigation by SB was attributed to a deprotonation mechanism reduced EPS adsorption on negatively charged membrane surfaces, and improvement of degradation efficiency of macromolecular organic matters. SB addition into MBRs for reject water treatment increased microbial abundance, enriched nitrifying bacteria, and converted predominant AOB genus from Nitrosomonas to Nitrosospira. PMID:26340030

  14. Stochastic modeling of filtrate alkalinity in water filtration devices: Transport through micro/nano porous clay based ceramic materials

    Science.gov (United States)

    Clay and plant materials such as wood are the raw materials used in manufacture of ceramic water filtration devices around the world. A step by step manufacturing procedure which includes initial mixing, molding and sintering is used. The manufactured ceramic filters have numerous pores which help i...

  15. The corrosion and electrochemical behavior of pure aluminum in additive-containing alkaline methanol-water mixed solutions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.B.; Wang, J.M.; Shao, H.B.; Chang, X.T.; Wang, L. [Department of Chemistry, Zhejiang University, Hangzhou (China); Zhang, J.Q.; Cao, C.N. [Department of Chemistry, Zhejiang University, Hangzhou (China); State Key Laboratory for Corrosion and Protection of Metal, Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China)

    2009-04-15

    The corrosion and electrochemical behavior of aluminum in inhibited and uninhibited 4 M KOH-methanol-water mixed solutions with a methanol/water volume ratio of 3:2 were investigated by means of hydrogen collection, polarization curve, galvanostatic discharge, and electrochemical impedance spectroscopy (EIS). The results of hydrogen collection and electrochemical experiments showed that the addition of ZnO can obviously inhibit the corrosion of aluminum in the 4 M KOH-methanol-water solutions, and its inhibition effect can be enhanced in the hydroxytryptamine (HT)-containing KOH solution. The results of scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDAX) revealed that ZnO produces the inhibition effect by the formation of a zinc-containing deposit layer on the surface of aluminum, and the cooperative effect of ZnO and HT may improve the deposit of zinc. The results of galvanostatic discharge indicated that aluminum can present good electrochemical activity in the 4 M KOH-methanol-water solution with 0.2 M ZnO and 1.0 mL/L HT. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  16. Characterization of the Bacterial and Sulphate Reducing Community in the Alkaline and Constantly Cold Water of the Closed Kotalahti Mine

    Directory of Open Access Journals (Sweden)

    Malin Bomberg

    2015-07-01

    Full Text Available Drainage from metal-sulphide rich rocks may cause considerable environmental stress in the form of elevated sulphate and heavy metal contamination of the environment. Mine draining effects from closed mines may be abated using indigenous and introduced microbial communities for sulphate reduction and metal precipitation at the mining site. Here we characterized the general and sulphate reducing bacterial (SRB community of Kotalahti Mine (Finland. The mine was flooded after closure and sulphate reduction and metal precipitation was induced by addition of pig manure sludge into the Vehkankuilu shaft. Water was sampled from Vehkankuilu and Ollinkuilu shafts from depths −10, −30, −70 and −100 m 15 years after the treatment. The water in the shafts differed from each other biologically and geochemically. The shafts are not directly connected except by some fracture zones, and the Ollinkuilu shaft is used as a reference for environmental monitoring. The detected bacterial communities from both shafts contained methylotrophic γ-Proteobacteria, hydrogenotrophic and methylotrophic β-Proteobacteria and fermenting bacterial clades. The concentration of SRB was low, at most 4.0 × 103 dsrB genes·mL−1, and the SRB affiliated with Desulfobulbus and Thermoanaerobacteriales clades. Despite the obvious success of the mine as an in situ bioreactor for increasing water pH and removing sulphate and heavy metals by induced sulphate reduction under suboptimal temperature, only a small portion, less than 0.5%, of the bacterial population in the mine water was SRB.

  17. Hypersensitivity of Ranunculus asiaticus to salinity and alkaline pH in irrigation water in sand cultures

    Science.gov (United States)

    Ranunculus, grown as a field crop in southern and central coastal California, is highly valued in the cut flower and tuberous root markets. Concerns regarding the sustainability of Ranunculus cultivation have arisen when the plantations are irrigated with municipal-treated waters. Although cut flo...

  18. The Production and Characterization of Ceramic Carbon Electrode Materials for CuCl-HCl Electrolysis

    Science.gov (United States)

    Edge, Patrick

    Current H2 gas supplies are primarily produced through steam methane reforming and other fossil fuel based processes. This lack of viable large scale and environmentally friendly H2 gas production has hindered the wide spread adoption of H2 fuel cells. A potential solution to this problem is the Cu-Cl hybrid thermochemical cycle. The cycle captures waste heat to drive two thermochemical steps creating CuCl as well as O2 gas and HCl from CuCl2 and water. The CuCl is oxidized in HCl to produce H2 gas and regenerate CuCl2, this process occurs at potentials well below those required for water electrolysis. The electrolysis process occurs in a traditional PEM fuel-cell. In the aqueous anolyte media Cu(I) will form anionic complexes such as CuCl 2 - or CuCl32-. The slow transport of these species to the anode surface limits the overall electrolysis process. To improve this transport process we have produced ceramic carbon electrode (CCE) materials through a sol-gel method incorporating a selection of amine containing silanes with increasing numbers of primary and secondary amines. When protonated these amines allow for improved transport of anionic copper complexes. The electrochemical and physical characterization of these CCE materials in a half and full-cell electrolysis environment will be presented. Electrochemical analysis was performed using cell polarization, cyclic voltammetry, and electrochemical impedance spectroscopy.

  19. Geochemical study of water-rock interaction processes on geothermal systems of alkaline water in granitic massif; Estudio geoquimico de los procesos de interaccion agua-roca sobre sistemas goetermales de aguas alcalinas en granitoides

    Energy Technology Data Exchange (ETDEWEB)

    Buil gutierrez, B.; Garcia Sanz, S.; Lago San Jose, M.; Arranz Uague, E.; Auque Sanz, L. [Universidad de Zaragoza (Spain)

    2002-07-01

    The study of geothermal systems developed within granitic massifs (with alkaline waters and reducing ORP values) is a topic of increasing scientific interest. These systems are a perfect natural laboratory for studying the water-rock interaction processes as they are defined by three main features: 1) long residence time of water within the system, 2) temperature in the reservoir high enough to favour reaction kinetics and finally, 3) the comparison of the chemistry of the incoming and outgoing waters of the system allows for the evaluation of the processes that have modified the water chemistry and its signature, The four geothermal systems considered in this paper are developed within granitic massifs of the Spanish Central Pyrenes; these systems were studied from a geochemical point of view, defining the major, trace and REE chemistry of both waters and host rocks and then characterizing the composition and geochemical evolution of the different waters. Bicarbonate-chloride-sodic and bicarbonate-sodic compositions are the most representative of the water chemistry in the deep geothermal system, as they are not affected by secondary processes (mixing, conductive cooling, etc). (Author)

  20. Electrochemical reduction of CO 2 in solid oxide electrolysis cells

    Science.gov (United States)

    Zhan, Zhongliang; Zhao, Lin

    This paper describes results on the electrochemical reduction of carbon dioxide using the same device as the typical planar nickel-YSZ cermet electrode supported solid oxide fuel cells (H 2-CO 2, Ni-YSZ|YSZ|LSCF-GDC, LSCF, air). Operation in both the fuel cell and the electrolysis mode indicates that the electrodes could work reversibly for the charge transfer processes. An electrolysis current density of ≈1 A cm -2 is observed at 800 °C and 1.3 V for an inlet mixtures of 25% H 2-75% CO 2. Mass spectra measurement suggests that the nickel-YSZ cermet electrode is highly effective for reduction of CO 2 to CO. Analysis of the gas transport in the porous electrode and the adsorption/desorption process over the nickel surface indicates that the cathodic reactions are probably dominated by the reduction of steam to hydrogen, whereas carbon monoxide is mainly produced via the reverse water gas shift reaction.

  1. Cathode for tritium-forming exothermic reaction by electrolysis

    International Nuclear Information System (INIS)

    The present invention provides a cathode used for a reaction in which liquid containing heavy water is electrolyzed under a room temperature to generate energy greater than that required for electrolysis in the liquid. The cathode used in this electrolysis includes any of those described below. (a) metal uranium (U metal) coated with palladium (Pd), (b) U metal contained in porous aluminum (Al203) container and (c) an alloy of U metal and Pd metal contained in a porous aluminum container. According to the result of an experiment, the temperature of the electrolyte is elevated to 40degC at 50 min after the start of electric supply and tritium in the electrolyte is increased to about three times of background, by using any one of cathodes (a), (b) and (c). Based on the result of the experiment, it is assumed that a specific tritium-forming exothermic reaction like that a nuclear fusion reaction is caused in this reaction. (I.S.)

  2. Straddling the tholeiitic/calc-alkaline transition: the effects of modest amounts of water on magmatic differentiation at Newberry Volcano, Oregon

    Science.gov (United States)

    Mandler, Ben E.; Donnelly-Nolan, Julie M.; Grove, Timothy L.

    2014-10-01

    Melting experiments have been performed at 1 bar (anhydrous) and 1- and 2-kbar H2O-saturated conditions to study the effect of water on the differentiation of a basaltic andesite. The starting material was a mafic pumice from the compositionally zoned tuff deposited during the ~75 ka caldera-forming eruption of Newberry Volcano, a rear-arc volcanic center in the central Oregon Cascades. Pumices in the tuff of Newberry caldera (TNC) span a continuous silica range from 53 to 74 wt% and feature an unusually high-Na2O content of 6.5 wt% at 67 wt% SiO2. This wide range of magmatic compositions erupted in a single event makes the TNC an excellent natural laboratory in which to study the conditions of magmatic differentiation. Our experimental results and mineral-melt hygrometers/thermometers yield similar estimates of pre-eruptive H2O contents and temperatures of the TNC liquids. The most primitive (mafic) basaltic andesites record a pre-eruptive H2O content of 1.5 wt% and a liquidus temperature of 1,060-1,070 °C at upper crustal pressure. This modest H2O content produces a distinctive fractionation trend that is much more enriched in Na, Fe, and Ti than the calc-alkaline trend typical of wetter arc magmas, but slightly less enriched in Fe and Ti than the tholeiitic trend of dry magmas. Modest H2O contents might be expected at Newberry Volcano given its location in the Cascade rear arc, and the same fractionation trend is also observed in the rim andesites of the rear-arc Medicine Lake volcano in the southern Cascades. However, the Na-Fe-Ti enrichment characteristic of modest H2O (1-2 wt%) is also observed to the west of Newberry in magmas erupted from the arc axis, such as the Shevlin Park Tuff and several lava flows from the Three Sisters. This shows that modest-H2O magmas are being generated directly beneath the arc axis as well as in the rear arc. Because liquid lines of descent are particularly sensitive to water content in the range of 0-3 wt% H2O, they provide a

  3. Summary of the Mol electrolysis cell test program in the CRL tritium laboratory

    International Nuclear Information System (INIS)

    The development of electrolysis technology for highly tritiated water at the Studiecentrum voor Kernenergie/Centre d'Etude de l'Energie Nucleaire (SCK/CEN), Mol, Belgium, focused on A Low Inventory Capillary Electrolyser (ALICE). The key characteristic of ALICE is its low liquid inventory, a key feature for the radio-toxicity of tritiated water. A program to test this electrolytic cell design with highly tritiated water in the Chalk River Tritium Laboratory was initiated in 1988 and extended through to early 1995. The activities conducted at CRL and associated with the experimental program-design, installation, licensing and commissioning activities- are described in this report along with the results of the test program conducted on the experimental system with non-tritiated heavy water. The installation in the CRL Tritium Laboratory consisted of three main sections: the electrolysis section, the tritium storage and supply section, and the recombination section. 16 figs., 2 tabs., 10 refs

  4. Syngas production by high temperature steam/CO2 coelectrolysis using solid oxide electrolysis cells.

    Science.gov (United States)

    Chen, Xinbing; Guan, Chengzhi; Xiao, Guoping; Du, Xianlong; Wang, Jian-Qiang

    2015-01-01

    High temperature (HT) steam/CO2 coelectrolysis with solid oxide electrolysis cells (SOECs) using the electricity and heat generated from clean energies is an important alternative for syngas production without fossil fuel consumption and greenhouse gas emissions. Herein, reaction characteristics and the outlet syngas composition of HT steam/CO2 coelectrolysis under different operating conditions, including distinct inlet gas compositions and electrolysis current densities, are systematically studied at 800 °C using commercially available SOECs. The HT coelectrolysis process, which has comparable performance to HT steam electrolysis, is more active than the HT CO2 electrolysis process, indicating the important contribution of the reverse water-gas shift reaction in the formation of CO. The outlet syngas composition from HT steam/CO2 coelectrolysis is very sensitive to the operating conditions, indicating the feasibility of controlling the syngas composition by varying these conditions. Maximum steam and CO2 utilizations of 77% and 76% are achieved at 1.0 A cm(-2) with an inlet gas composition of 20% H2/40% steam/40% CO2. PMID:26204849

  5. Contact glow discharge electrolysis: its origin, plasma diagnostics and non-faradaic chemical effects

    Science.gov (United States)

    Gupta, Susanta K. Sen

    2015-12-01

    Contact glow discharge electrolysis (CGDE) also termed plasma electrolysis is a novel electrolysis where a stable sheath of light emitting plasma develops around an electrode immersed well inside a relatively high-conductivity liquid electrolyte during normal electrolysis (NE) at several hundred volts. The phenomenon may develop in dc-, pulsed dc-, ac- as well as RF-driven electrolyses. The chemical effects of CGDE are remarkably non-faradaic in respect to the nature of the products as well as their yields. The article traces comprehensively the progress made in studies of CGDE in aqueous and non-aqueous solutions since 1844 and reviews the developments in the understanding of its origin, light emission, plasma state and non-faradaic effects leading to the elucidation of detailed mechanism of the origin of CGDE on the basis of the onset of hydrodynamic instabilities in local vaporization of the solvent near the working electrode during NE, and that of highly non-faradaic effects of CGDE based on a model of two reaction zones located within the electrode plasma and at the plasma-liquid interface producing solvent derived radicals at high local concentrations. Keeping in view the recent surge of interest in varied applications of CGDE, the article is appended with highlights of these applications across synthetic chemistry, waste water treatment, electrosurgical devices, nanoparticle fabrications, surface engineering and micro-machining.

  6. Stray current control in electrolysis plant

    International Nuclear Information System (INIS)

    Stray current can appear in any industrial plant powered by electricity. In electrolysis plants the probability for stray current appearance is high due to the use of electrolytes, which are current-conductive liquid media. Busbars, metallic equipment, electrolyte, the ground and the human body are to a different extent DC current-conductive. Brought in contact in an electrolysis plant, they act as a complex electrical network supplied by a rectifier. As a result, uncontrolled stray currents can flow causing hazard (even electrocution) to the operating personal, power loss and/or damage to the equipment. Despite its major importance for all metal winning and refining electrolysis processes, the stray current issue is very scarcely treated in the published literature. This paper reveals the fundamentals for stray current appearance pointing out to the two major loops in the plant. In the internal loop stray current flows through the electrolyte distribution system causing power loss and hardware damage by stray current induced corrosion. The heat exchanger used for electrolyte preheating is especially critical. The external stray current loop covers stray current cases caused by electrolyte leakage. It impacts on power losses and hazards to the personnel. LUSCURE (LUrgi Stray-CUrrent-cuRE) is a new method for localization, control and reduction of stray current in an electrolysis plant. It involves a translation of the plant and equipment design into an equivalent electrical circuit that is calculated and analysed. LUSCURE was verified by assessing a German copper refinery and by being extensively used in plant and equipment design for the High Current Density Copper Electrowinning Process (HCD). (author)

  7. Performance and durability of solid oxide electrolysis cells

    DEFF Research Database (Denmark)

    Hauch, Anne; Jensen, Søren H; Ramousse, Severine; Mogensen, Mogens Bjerg

    2006-01-01

    Solid oxide fuel cells produced at Riso National Laboratory have been tested as electrolysis cells by applying an external voltage. Results on initial performance and durability of such reversible solid oxide cells at temperatures from 750 to 950 degrees C and current densities from -0.25 A/cm(2......) to -0.50 A/cm(2) are reported. The full cells have an initial area specific resistance as low as 0.27 Omega cm(2) for electrolysis operation at 850 degrees C. During galvanostatic long-term electrolysis tests, the cells were observed to passivate mainly during the first similar to 100 h of...... electrolysis. Cells that have been passivated during electrolysis tests can be partly activated again by operation in fuel cell mode or even at constant electrolysis conditions after several hundred hours of testing....

  8. Solid Oxide Electrolysis for Oxygen Production in an ARS Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Paragon Space Development Corporation proposes an innovative, efficient and practical concept that utilizes Solid Oxide Electrolysis for regenerative air...

  9. Simple electrolyzer model development for high-temperature electrolysis system analysis using solid oxide electrolysis cell

    International Nuclear Information System (INIS)

    An electrolyzer model for the analysis of a hydrogen production system using a solid oxide electrolysis cell has been developed, and the effects of principal parameters have been estimated via sensitivity studies based on the developed model. The main parameters considered were current density, area-specific resistance, temperature, pressure, molar fraction, and flow rates in the inlet and outlet. A simple model is also estimated for a high-temperature hydrogen production system that integrates the solid oxide electrolysis cell with a very high temperature reactor. (author)

  10. Simple Electrolyzer Model Development for High-Temperature Electrolysis System Analysis Using Solid Oxide Electrolysis Cell

    International Nuclear Information System (INIS)

    An electrolyzer model for the analysis of a hydrogen-production system using a solid oxide electrolysis cell (SOEC) has been developed, and the effects for principal parameters have been estimated by sensitivity studies based on the developed model. The main parameters considered are current density, area specific resistance, temperature, pressure, and molar fraction and flow rates in the inlet and outlet. Finally, a simple model for a high-temperature hydrogen-production system using the solid oxide electrolysis cell integrated with very high temperature reactors is estimated.

  11. A Novel Technique for Wastewater Treatment by Contact Glow-discharge Electrolysis

    Directory of Open Access Journals (Sweden)

    Jinzhang Gao

    2006-01-01

    Full Text Available The min-review gives a brief introduction to contact glow-discharge electrolysis, a novel technique for wastewater treatment. The literatures concerning the basic principle are cited rather than the all, emphasizing on the degradation of organic pollutants in water. Now, the application is only limited in a small amount of water sample, the larger scale test has not been made. However, as a new method for purification of water, at least, the discussion is beneficial to the treatment of decentralized water or cellar water.

  12. Theoretical and experimental investigation of cappillary electrolysis system

    International Nuclear Information System (INIS)

    In a fusion reactor environment, it is expected that highly tritiated water will be formed when tritium is extracted from the blanket as well as during the plasma exhaust purification process. As a consequence, the recovery of elemental tritium from its oxides is an essentrial step before recycling the fuel to the reactor. Among different basic processes that can be used for this purpose, electrolysis appears to be very promising. Therefore, SCK/CEN has developed a small dedicated cell designed to decompose 100 ml/day of pure DTO or HTO. At the present project stage, a prototype cell is available and the device has been successfully tested with light water during several thousands of hours. In the orginal concept, the liquid inventory is limited to the vertical porous gas separator. Capillarity is used as a driving force to feed the cell to avoid the use of a pump. This fact turns out to have a considerable influence on the behaviour of the electrolytic system. This particular behaviour has been theorectically investigated with the aim to allow a better basic understanding of the capillary electrolysis. A deterministic model has been developed for its purpose. The mathematical equations show clearly that the electrolyte tends to accumulate at the top of the gas separator. An equilibrium state can be reached only if sufficiently large amounts of electrolyte can flow back towards the bottom of the gas separator. This counter-flow has been taken into account by introducing a single general diffusion coefficient into the model. In a second phase, systematic experimental runs have been carried out with mock-up cells. A statistical treatment based on the maximum likelihood estimation algorithm allowed to compute the best values for the diffusion coefficient and to validate the model. Finally, acceptabel ranges of the independent varialbles have been defined and all the subsequent experimental runs have been performed without stability problems. (author). 12 refs.; 5 figs

  13. Electrochemistry in aqueous solution at high temperature and under pressure: study of nickel in a highly alkaline environment

    International Nuclear Information System (INIS)

    This research thesis reports the study of the corrosion resistance and anodic behaviour of various metals and alloys used in conventional thermal or nuclear power stations, more particularly the case of nickel in a highly alkaline environment (KOH 5 N) which is widely used for hydrogen production by water electrolysis. The author studied the influence of temperature and pressure on the electrochemical behaviour of nickel, and more particularly the first-oxidation kinetics. The report discusses the physicochemical and thermodynamic properties of aqueous systems at high temperature and under pressure, presents the general techniques of high-temperature electrochemistry, describes the experimental installation, and reports the development of a reference electrode which can operate in those experimental conditions. The author reports the study of the electrochemical behaviour of nickel in alkaline environment and at high temperature, reports a surface analysis performed by Auger spectroscopy, electron spectroscopy for chemical analysis or ESCA, and scanning electronic microscopy, reports the study of the electrochemical behaviour of nickel in a potassium hydroxide solution under normal temperature and pressure, but also in acid environment. Results are interpreted with respect to temperature

  14. LIQUID BIO-FUEL PRODUCTION FROM NON-FOOD BIOMASS VIA HIGH TEMPERATURE STEAM ELECTROLYSIS

    Energy Technology Data Exchange (ETDEWEB)

    G. L. Hawkes; J. E. O' Brien; M. G. McKellar

    2011-11-01

    cycle for electricity generation is 50%, (as expected from GEN IV nuclear reactors), the syngas production efficiency ranges from 70% to 73% as the gasifier temperature decreases from 1900 K to 1500 K. Parametric studies of system pressure, biomass moisture content and low temperature alkaline electrolysis are also presented.

  15. Alkaline "Permanent" Paper.

    Science.gov (United States)

    Pacey, Antony

    1991-01-01

    Discussion of paper manufacturing processes and their effects on library materials focuses on the promotion of alkaline "permanent" paper, with less acid, by Canadian library preservation specialists. Standards for paper acidity are explained; advantages of alkaline paper are described, including decreased manufacturing costs; and recyclability is…

  16. Microbial electrolysis cells for production of methane from CO2: long-term performance and perspectives

    OpenAIRE

    Eerten-Jansen, van, M.C.A.A.; Heijne, ter, A.; C J N Buisman; Hamelers, H.V.M.

    2012-01-01

    A methane-producing microbial electrolysis cell (MEC) is a technology to convert CO2 into methane, using electricity as an energy source and microorganisms as the catalyst. A methane-producing MEC provides the possibility to increase the fuel yield per hectare of land area, when the CO2 produced in biofuel production processes is converted to additional fuel methane. Besides increasing fuel yield per hectare of land area, this also results in more efficient use of land area, water, and nutrie...

  17. Role of Iron Anode Oxidation on Transformation of Chromium by Electrolysis

    OpenAIRE

    Sarahney, Hussam; Mao, Xuhui; Alshawabkeh, Akram N.

    2012-01-01

    The potential for chemical reduction of hexavalent chromium Cr(VI) in contaminated water and formation of a stable precipitate by Zero Valent Iron (ZVI) anode electrolysis is evaluated in separated electrodes system. Oxidation of iron electrodes produces ferrous ions causing the development of a reducing environment in the anolyte, chemical reduction of Cr(VI) to Cr(III) and formation of stable iron-chromium precipitates. Cr(VI) transformation rates are dependent on the applied electric curre...

  18. A Comparison of Half Bridge & Full Bridge Isolated DC-DC Converters for Electrolysis Application

    OpenAIRE

    R.Samuel Rajesh Babu; Joseph Henry

    2011-01-01

    This paper presents a comparison of half bridgeand full bridge isolated, soft-switched, DC-DC converters forElectrolysis application. An electrolyser is a part of renewableenergy system which generates hydrogen from water electrolysisthat used in fuel cells. A DC-DC converter is required to coupleelectrolyser to system DC bus. The proposed DC-DC converter isrealized in both full-bridge and half-bridge topology in order toachieve zero voltage switching for the power switches and toregulate the...

  19. Catalytic dechlorination of diclofenac by biogenic palladium in a microbial electrolysis cell

    OpenAIRE

    De Gusseme, Bart; Soetaert, Maarten; Hennebel, Tom; Vanhaecke, Lynn; Boon, Nico; Verstraete, Willy

    2012-01-01

    Summary Diclofenac is one of the most commonly detected pharmaceuticals in wastewater treatment plant (WWTP) effluents and the receiving water bodies. In this study, biogenic Pd nanoparticles (‘bio‐Pd’) were successfully applied in a microbial electrolysis cell (MEC) for the catalytic reduction of diclofenac. Hydrogen gas was produced in the cathodic compartment, and consumed as a hydrogen donor by the bio‐Pd on the graphite electrodes. In this way, complete dechlorination of 1 mg diclofenac ...

  20. Competitiveness of hydrogen production by High Temperature Electrolysis: Impact of the heat source and identification of key parameters to achieve low production costs

    International Nuclear Information System (INIS)

    Among the more efficient and sustainable processes that are studied for massive hydrogen production, High Temperature steam Electrolysis seems a promising process. When operating in the autothermal mode, this process does not require a high temperature source for the electrolysis reaction but only a thermal energy source able to supply enough heat to vaporize water. Using a simplified economic model, we assess the impact of the temperature, pressure and thermal energy cost of the heat source on the process competitiveness. Results show that medium temperature thermal energy sources could be coupled to the High Temperature Electrolysis process without resulting in strong overcosts. Besides, key parameters are also identified among the electrolyzer characteristics. Relevant results indicate that R and D on electrolysis cells must continue focusing on the lifespan of these equipments, for which a target lifespan of 3 years could be established.

  1. Solid oxide electrolysis cells - Performance and durability

    Energy Technology Data Exchange (ETDEWEB)

    Hauch, A.

    2007-10-15

    In this work H2 electrode supported solid oxide cells (SOC) produced at Risoe National Laboratory, DTU, have been used for steam electrolysis. Electrolysis tests have been performed at temperatures from 650AeC to 950AeC, p(H2O)/p(H2) from 0.99/0.01 to 0.30/0.70 and current densities from -0.25 A/cm2 to -2 A/cm2. The solid oxide electrolysis cells (SOEC) have been characterised by iV curves and electrochemical impedance spectroscopy (EIS) at start and end of tests and by EIS under current load during electrolysis testing. The tested SOCs have shown the best initial electrolysis performance reported in literature to date. Area specific resistances of 0.26 Oecm2 at 850AeC and 0.17 Oecm2 at 950AeC were obtained from electrolysis iV curves. The general trend for the SOEC tests was: 1) a short-term passivation in first few hundred hours, 2) then an activation and 3) a subsequent and underlying long-term degradation. The transient phenomenon (passivation/activation) was shown to be a set-up dependent artefact caused by the albite glass sealing with a p(Si(OH)4) of 1.10-7 atm, leading to silica contamination of the triple-phase boundaries (TPBs) of the electrode. The long-term degradation for the SOECs was more pronounced than for fuel cell testing of similar cells. Long-term degradation of 2%/1000 h was obtained at 850AeC, p(H2O)/p(H2) = 0.5/0.5 and -0.5 A/cm2, whereas the degradation rate increased to 6%/1000h at 950AeC, p(H2O)/p(H2) = 0.9/0.1 and -1.0 A/cm2. Both the short-term passivation and the long-term degradation appear mainly to be related to processes in the H2 electrode. Scanning electron microscopy micrographs show that only limited changes occur in the Ni particle size distribution and these are not the main degradation mechanism for the SOECs. Micro and nano analysis using energy dispersive spectroscopy in combination with transmission electron microscopy (TEM) and scanning TEM reveals that glassy phase impurities have accumulated at the TPBs as a result of

  2. Investigation of the Alkaline Electrochemical Interface and Development of Composite Metal/Metal-Oxides for Hydrogen and Oxygen Electrodes

    Science.gov (United States)

    Bates, Michael

    Understanding the fundamentals of electrochemical interfaces will undoubtedly reveal a path forward towards a society based on clean and renewable energy. In particular, it has been proposed that hydrogen can play a major role as an energy carrier of the future. To fully utilize the clean energy potential of a hydrogen economy, it is vital to produce hydrogen via water electrolysis, thus avoiding co-production of CO2 inherent to reformate hydrogen. While significant research efforts elsewhere are focused on photo-chemical hydrogen production from water, the inherent low efficiency of this method would require a massive land-use footprint to achieve sufficient hydrogen production rates to integrate hydrogen into energy markets. Thus, this research has primarily focused on the water splitting reactions on base-metal catalysts in the alkaline environment. Development of high-performance base-metal catalysts will help move alkaline water electrolysis to the forefront of hydrogen production methods, and when paired with solar and wind energy production, represents a clean and renewable energy economy. In addition to the water electrolysis reactions, research was conducted to understand the de-activation of reversible hydrogen electrodes in the corrosive environment of the hydrogen-bromine redox flow battery. Redox flow batteries represent a promising energy storage option to overcome the intermittency challenge of wind and solar energy production methods. Optimization of modular and scalable energy storage technology will allow higher penetration of renewable wind and solar energy into the grid. In Chapter 1, an overview of renewable energy production methods and energy storage options is presented. In addition, the fundamentals of electrochemical analysis and physical characterization of the catalysts are discussed. Chapter 2 reports the development of a Ni-Cr/C electrocatalyst with unprecedented mass-activity for the hydrogen evolution reaction (HER) in alkaline

  3. Microstructural and chemical changes after high temperature electrolysis in solid oxide electrolysis cell

    Energy Technology Data Exchange (ETDEWEB)

    Mahata, Arup; Datta, Pradyot; Basu, Rajendra N., E-mail: rnbasu@cgcri.res.in

    2015-04-05

    Highlights: • Hydrogen production by running SOEC single cell. • Delamination of anode layer from the electrolyte. • Lanthanum zirconate formation due to high partial pressure of oxygen at the anode. • Formation of yttrium silicate due to diffusion of silica at the cathode side. - Abstract: Degradation of solid oxide electrolysis cell is probably the main problem in the field of high temperature steam electrolysis. In this study two anode-supported solid oxide fuel cells were tested as a solid oxide electrolysis cell operating from 875 °C to 950 °C at the applied voltage of 1.5 V and 1.7 V respectively. Microstructural and chemical changes of the cell components were studied by field emission scanning electron microscope (FESEM), and X-ray diffraction (XRD) analysis before and after the electrolysis. FESEM analysis shows a delamination of anode layer from the electrolyte. Furthermore, formation of impurities like yttrium silicate at the cathode–electrolyte interface and lanthanum zirconate (LZ) at the anode–electrolyte interface were observed after electrolysis. It also reveals that lanthanum zicronate is formed only at the interfaces between anode functional layer La{sub 0.65}Sr{sub 0.3}MnO{sub 3−δ} (LSM)/8 mol% yttria stabilized zirconia (YSZ) and electrolyte layer (YSZ) but not at the whole anode layer. Formation of LZ is attributed to the high partial pressure of oxygen at the anode–electrolyte interface while yttrium silicate is formed due to the diffusion of silica from glass sealant into the cathode layer.

  4. Microstructural and chemical changes after high temperature electrolysis in solid oxide electrolysis cell

    International Nuclear Information System (INIS)

    Highlights: • Hydrogen production by running SOEC single cell. • Delamination of anode layer from the electrolyte. • Lanthanum zirconate formation due to high partial pressure of oxygen at the anode. • Formation of yttrium silicate due to diffusion of silica at the cathode side. - Abstract: Degradation of solid oxide electrolysis cell is probably the main problem in the field of high temperature steam electrolysis. In this study two anode-supported solid oxide fuel cells were tested as a solid oxide electrolysis cell operating from 875 °C to 950 °C at the applied voltage of 1.5 V and 1.7 V respectively. Microstructural and chemical changes of the cell components were studied by field emission scanning electron microscope (FESEM), and X-ray diffraction (XRD) analysis before and after the electrolysis. FESEM analysis shows a delamination of anode layer from the electrolyte. Furthermore, formation of impurities like yttrium silicate at the cathode–electrolyte interface and lanthanum zirconate (LZ) at the anode–electrolyte interface were observed after electrolysis. It also reveals that lanthanum zicronate is formed only at the interfaces between anode functional layer La0.65Sr0.3MnO3−δ (LSM)/8 mol% yttria stabilized zirconia (YSZ) and electrolyte layer (YSZ) but not at the whole anode layer. Formation of LZ is attributed to the high partial pressure of oxygen at the anode–electrolyte interface while yttrium silicate is formed due to the diffusion of silica from glass sealant into the cathode layer

  5. The effects of electrolysis in electromembrane extractions

    Czech Academy of Sciences Publication Activity Database

    Šlampová, Andrea; Kubáň, Pavel; Boček, Petr

    Grupo VLS Print Solution, 2014 - (Guzman, N.; Taveres, M.). s. 180-180 [ITP & LACE 2014. International Symposium on Electro- and Liquid Phase-Separation Techniques /21./ and Latin-American Symposium on Biotechnology, Biomedical, Biopharmaceutical, and Industrial Applications of Capillary Electrophoresis and Microchip Technology /20./. 04.10.2014-08.10.2014, Natal] R&D Projects: GA ČR(CZ) GA13-05762S Institutional support: RVO:68081715 Keywords : electromembrane extractions * electrolysis * extraction performance Subject RIV: CB - Analytical Chemistry, Separation

  6. -Based Cermet Inert Anodes for Aluminum Electrolysis

    Science.gov (United States)

    Tian, ZhongLiang; Lai, YanQing; Li, ZhiYou; Chai, DengPeng; Li, Jie; Liu, YeXiang

    2014-11-01

    The new aluminum electrolysis technology based on inert electrodes has received much interest for several decades because of the environment and energy advantages. The key to realize this technique is the inert anode. This article presents China's recent developments of NiFe2O4-based cermet inert anodes, which include the optimization of material performance, the joint between the cermet inert anode and metallic bar, as well as the results of 20 kA pilot testing for a large-size inert anode group. The problems NiFe2O4-based cermet inert anodes face are also discussed.

  7. Degradation in Solid Oxide Cells During High Temperature Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Manohar Sohal

    2009-05-01

    Idaho National Laboratory has an ongoing project to generate hydrogen from steam using solid oxide electrolysis cells. One goal of that project is to address the technical and degradation issues associated with solid oxide electrolysis cells. This report covers a variety of these degradation issues, which were discussed during a workshop on “Degradation in Solid Oxide Electrolysis Cells and Strategies for its Mitigation,” held in Phoenix, AZ on October 27, 2008. Three major degradation issues related to solid oxide electrolysis cells discussed at the workshop are: • Delamination of O2-electrode and bond layer on steam/O2-electrode side • Contaminants (Ni, Cr, Si, etc.) on reaction sites (triple-phase boundary) • Loss of electrical/ionic conductivity of electrolyte. This list is not all inclusive, but the workshop summary can be useful in providing a direction for future research related to the degradation of solid oxide electrolysis cells.

  8. Alkaline battery operational methodology

    Energy Technology Data Exchange (ETDEWEB)

    Sholklapper, Tal; Gallaway, Joshua; Steingart, Daniel; Ingale, Nilesh; Nyce, Michael

    2016-08-16

    Methods of using specific operational charge and discharge parameters to extend the life of alkaline batteries are disclosed. The methods can be used with any commercial primary or secondary alkaline battery, as well as with newer alkaline battery designs, including batteries with flowing electrolyte. The methods include cycling batteries within a narrow operating voltage window, with minimum and maximum cut-off voltages that are set based on battery characteristics and environmental conditions. The narrow voltage window decreases available capacity but allows the batteries to be cycled for hundreds or thousands of times.

  9. SUMMERTIME FRESH WATER FRACTIONS IN THE SURFACE WATER OF THE WESTERN ARCTIC OCEAN EVALUATED FROM TOTAL ALKALINITY%夏季西北冰洋表层淡水分布的总碱度示踪研究

    Institute of Scientific and Technical Information of China (English)

    高众勇; 孙恒; 陈立奇; 张凡

    2012-01-01

    As a quasi-conservative tracer, total alkalinity ( TA) can be used to tracethe relative fractions of fresh water and sea water. In this study, based on TA and related data collected during the Third Chinese Arctic Research Expedition (July-September 2008, CHINARE-2008) and the Fourth Chinese Arctic Research Expedition ( July-September 2010, CHINARE-2010) , fractions of sea ice meltwater, river runoff and sea water in the surface water of the western Arctic Ocean were determined from salinity and TA relationships. During hoth surveys, the largest fraction of sea ice meltwater was found around 75°N in the Canada Basin, located at the ice edge. Generally, the fraction of river runoff is less than sea ice meltwater. The river runoff, composed mainly of Yukon River water carried by Bering inflow water and Mackenzie River water, was influenced by currents, and there were two areas where its fraction peaked. Our results showed that the dilution effect of fresh water carried by Bering inflow water during CHINARE-2008 might have been stronger than during CHINARE-2010. The area of the peak sea ice meltwater fraction identified during CHINARE-2010 differed from CHINARE-2008, corresponding to different sea ice conditions.%利用中国第三次和第四次北极科学考察在西北冰洋测定的海水总碱度资料和相关资料,结合海水、海冰融化水及河源淡水3个端元盐度和总碱度的特征值,计算分析了夏季表层海水中淡水所占的比例.示踪研究结果表明,加拿大海盆南部海冰融化水所占比例最大,该区为海冰剧烈融化的冰缘带.径流水的比例明显低于海冰融化水的比例,径流水主要来自白令海人流水中携带的Yukon河水和加拿大Mackenzie河水的输入c 2008年夏季海冰融化水以及由白令海人流水输入的淡水量都明显比2010年大,由Mackenzie河水带来的淡水影响变化不大,但其影响的峰值区域位置有所偏移,与海冰分布区相对应.

  10. Treatment of linear alkylbenzene sulfonate (LAS) wastewater by internal electrolysis--biological contact oxidation process.

    Science.gov (United States)

    Cao, X Z; Li, Y M

    2011-01-01

    Surfactant wastewater is usually difficult to treat due to its toxicity and poor biodegradability. A separate physico-chemical or biochemical treatment method achieves a satisfactory effect with difficulty. In this study, treatment of the wastewater collected from a daily chemical plant by the combination processes of Fe/C internal electrolysis and biological contact oxidation was investigated. For the internal electrolysis process, the optimal conditions were: pH = 4-5, Fe/C = (10-15):1, air-water ratio = (10-20):1 and hydraulic retention time (HRT)= 2 h. For the biological contact oxidation process, the optimal conditions were: HRT = 12 h, DO = 4.0-5.0 mg/L. Treated by the above combined processes, the effluent could meet the I-grade criteria specified in Integrated Wastewater Discharge Standard of China (GB 8978-1996). The results provide valuable information for full-scale linear alkylbenzene sulfonate wastewater treatment. PMID:22053469

  11. Solid oxide electrolysis cell analysis by means of electrochemical impedance spectroscopy: A review

    Science.gov (United States)

    Nechache, A.; Cassir, M.; Ringuedé, A.

    2014-07-01

    High temperature water electrolysis based on Solid Oxide Electrolysis Cell (SOEC) is a very promising solution to produce directly pure hydrogen. However, degradation issues occurring during operation still represent a scientific and technological barrier in view of its development at an industrial scale. Electrochemical Impedance Spectroscopy (EIS) is a powerful in-situ fundamental tool adapted to the study of SOEC systems. Hence, after a quick presentation of EIS principle and data analysis methods, this review demonstrates how EIS can be used: (i) to characterize the performance and mechanisms of SOEC electrodes; (ii) as a complementary tool to study SOEC degradation processes for different cell configurations, in addition to post-test tools such as scanning electron microscopy (SEM) or X-ray diffraction (XRD). The use of EIS to establish a systematic SOEC analysis is introduced as well.

  12. Uranium in alkaline rocks

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.

    1978-04-01

    Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential.

  13. Uranium in alkaline rocks

    International Nuclear Information System (INIS)

    Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential

  14. Durable SOC stacks for production of hydrogen and synthesis gas by high temperature electrolysis

    DEFF Research Database (Denmark)

    Ebbesen, Sune Dalgaard; Høgh, Jens Valdemar Thorvald; Nielsen, Karsten Agersted;

    2011-01-01

    Electrolysis of steam and co-electrolysis of steam and carbon dioxide was studied in Solid Oxide Electrolysis Cell (SOEC) stacks composed of Ni/YSZ electrode supported SOECs. The results of this study show that long-term electrolysis is feasible without notable degradation in these SOEC stacks. T...

  15. Cathodic electrolysis method of depositing cerium conversion films on industrial pure aluminum

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Two two-step techniques, called TS2/TS7 and TS3/TS7, respectively, have been developed to form cerium conversion films on the surface of industrial pure aluminum. The tested material was cathodically electrolyzed in the alkaline solution containing cerium salt, and uniform films containing cerium were obtained after the two-step treatment. It is found that the films obtained by TS2/TS7 and TS3/TS7 techniques are about 4.0 and 3.0 m in thickness, respectively. The material has better corrosion resistance in the chloride solution after the two-step electrolysis treatment compared with the one-step treated and naked specimens.

  16. Corrosion of ruthenium dioxide based cathodes in alkaline medium caused by reverse currents

    International Nuclear Information System (INIS)

    A reverse current obtained during power shutdowns in industrial processes, such as chlor-alkali production or alkaline water electrolysis, is deleterious for hydrogen evolving ruthenium dioxide (RuO2) based cathodes. It has been observed that RuO2 coatings after a power shutdown, necessary for e.g. maintenance, are severely damaged unless polarization rectifiers are employed. In this work we show why these types of cathodes are sensitive to reverse currents, i.e. anodic currents, after hydrogen evolution. RuO2 coatings deposited on nickel substrates were subjected to different electrochemical treatments such as hydrogen evolution, oxygen evolution, or reverse currents in 8 M NaOH at 90 °C. Polarity inversion was introduced after hydrogen evolution to simulate the effect of reverse currents. Because of chemical interaction with hydrogen, a significant amount of the RuO2 coating was transformed into hydroxylated species during cathodic polarization. Our study shows that these hydroxylated phases are highly sensitive to electrochemical corrosion during anodic polarization after extended hydrogen evolution

  17. An investigation of energy balances in palladium cathode electrolysis experiments

    International Nuclear Information System (INIS)

    In recently publicized cold fusion experiments at the University of Utah, generation of excess heat was reported. To investigate mechanisms that may contribute to energy flows in electrolysis cells, a series of experiments was performed at the Idaho National Engineering Laboratory (INEL). Ordinary water (H2O), heavy water (D2O), and mixture of the two were used in the INEL experiments. Cathodes used include a 51-μm Pd foil and 1-mm diameter extruded wire Pd rods in two configurations. Energy balances in these experiments revealed that some of the required voltage to sustain a given current is due to irreversibilities associated with cell operation. Particularly significant are electrolyte resistance and activation energy polarization effects. Energy balances in the INEL experiments showed there was no significant net grain or net loss of energy. Cell overpotential curves were fit well with a Tafel equation, with parameters dependent on electrode configuration, electrolyte composition, and temperature. Water evaporation and interactions of hydrogen isotopes with the Pd cathode were evaluated and found not to be significant to energy balances. No ionizing radiation, tritium production, or other evidence of fusion reactions was seen in the INEL experiments. 4 refs., 6 figs., 2 tabs

  18. Experimental Study of Plasma Under-liquid Electrolysis in Hydrogen Generation

    Institute of Scientific and Technical Information of China (English)

    严宗诚; 陈砺; 王红林

    2006-01-01

    The application and characteristics of relatively big volume plasma produced with cathodic glow discharges taking place across a gaseous envelope over the cathode which was dipped into electrolyte in hydrogen generation were studied. A critical investigation of the influence of methanol concentration and voltage across the circuit on the composition and power consumption per cubic meter of cathode liberating gas was carried out. The course of plasma under-liquid electrolysis has the typical characteristics of glow discharge electrolysis. The cathode liberating gas was in substantial excess of the Faraday law value. When the voltage across the circuit was equal to 550 V, the volume of cathodic gas with sodium carbonate solution was equal to 16.97 times the Faraday law value. The study showed that methanol molecules are more active than water molecules.The methanol molecules were decomposed at the plasma-catholyte interface by the radicals coming out the plasma mantle.Energy consumption per cubic meter of cathodic gases (WV) decreased while methanol concentration of the electrolytes increased. When methanol concentration equaled 5% (ψ), WV was 10.381×103 kJ/m3, less than the corresponding theoretic value of conventional water electrolysis method. The cathodic liberating gas was a mixture of hydrogen, carbon dioxide and carbon monoxide with over 95% hydrogen, if methanol concentration was more than 15% (ψ). The present research work revealed an innovative application of glow discharge and a new highly efficient hydrogen generation method, which depleted less resource and energy than normal electrolysis and is environmentally friendly.

  19. Electrolysis of carbon dioxide for carbon monoxide production in a tubular solid oxide electrolysis cell

    International Nuclear Information System (INIS)

    Highlights: • An experimental study for the CO regeneration was demonstrated. • Higher current densities at higher temperatures were obtained. • The scale of the combined system was estimated experimentally at 800 °C. • The required surface area of the cells was estimated to be 65.6 km2/BF unit. • The combined system may contribute to establishing a low-carbon society. - Abstract: An active carbon recycling energy system (ACRES) based on carbon recycling has been proposed as a new energy transformation system. This energy transformation system reduces the carbon dioxide (CO2) emissions in the atmosphere during the iron-making process. An experimental study for electrochemical CO production by CO2 electrolysis based on the ACRES concept was carried out using a tubular solid oxide electrolysis cell. Experimental results show that the CO and oxygen (O2) production rates at 800, 850, and 900 °C were almost proportional to the current passing through the cell. Both ionic conductivity and the chemical kinetics of CO2 decomposition increased with increasing temperature. The highest current density and CO production rate at 900 °C were 2.97 mA/cm2 and 0.78 μmol/(min cm2), respectively. On the basis of the electrolytic characteristics of the cell, the scale of the combined ACRES CO2 electrolysis/iron-making system was estimated

  20. Feasibility Study of Hydrogen Production from Existing Nuclear Power Plants Using Alkaline Electrolysis

    International Nuclear Information System (INIS)

    The mid-range industrial market currently consumes 4.2 million metric tons of hydrogen per year and has an annual growth rate of 15% industries in this range require between 100 and 1000 kilograms of hydrogen per day and comprise a wide range of operations such as food hydrogenation, electronic chip fabrication, metals processing and nuclear reactor chemistry modulation

  1. Feasibility Study of Hydrogen Production from Existing Nuclear Power Plants Using Alkaline Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Dana R. Swalla

    2008-12-31

    The mid-range industrial market currently consumes 4.2 million metric tons of hydrogen per year and has an annual growth rate of 15% industries in this range require between 100 and 1000 kilograms of hydrogen per day and comprise a wide range of operations such as food hydrogenation, electronic chip fabrication, metals processing and nuclear reactor chemistry modulation.

  2. Electrocatalysis of carbon anode in aluminium electrolysis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The anodic overvoltage of the carbon anode in aluminum electrolysis isof the order of 0.6 V at normal current densities. However, it can be reduced somewhat by doping the anode carbon with various inorganic compounds. A new apparatus was designed to improve the precision of overvoltage measurements. Anodes were doped with MgAl2O4 and AlF3 both by impregnation of the coke and by adding powder, and the measured overvoltage was compared with that of undoped samples. For prebake type anodes baked at around 1150 oC, the anodic overvoltage was reduced by 40-60 mV, and for Soderberg type anodes, baked at 950 oC, by 60-80 mV.

  3. Tritium-enrichment via CECE-process with high-temperature steam electrolysis (HOT ELLY)

    International Nuclear Information System (INIS)

    Reprocessing of nuclear fuel elements produces tritiated water which has to be disposed of for final storage. The amount of waste can be significantly reduced by tritium-enrichment. Besides distillation the CECE-process (Combined Electrolysis Catalytic Exchange) can be applied to that. The objective of the study was the investigation of questions concerning process engineering and safety aspects related to high-temperature steam electrolysis ('HOT ELLY') with respect to the potential for its application within the radioactive system of the CECE-process instead of a conventional electrolyzer. A process engineering concept for the integration of a high temperature electrolyzer into the CECE-process was designed. A comparative assessment with respect to the application of a conventional electrolysis-process revealed the usage of a high temperature electrolyzer to be attractive. Main advantages are significant reduction of the radioactive inventory and the avoiding of secondary waste. Prohibitive safety problems are not seen. (orig.) With 39 refs., 18 tabs., 38 figs

  4. Effect of Substrate Concentration to Anode Chamber Performance in Microbial Electrolysis Cell

    Directory of Open Access Journals (Sweden)

    Libertus Darus

    2015-11-01

    Full Text Available Microbial electrolysis is a promising process for bio-hydrogen production which might be implemented in waste water treatment in a near future. Unfortunately substrate could be converted into methane by acetoclastic methanogens and will reduce the coulombic efficiency (CE. The research objective was to study the competition between electrogens and methanogens for substrate in a continuous Microbial Electrolysis Cell (MEC.The competition was studied in relation to controlling acetate influent concentration (Cin from 35 to 1 mM with a fixed anode potential -350 mV, by assessing activity of electrogens as current density (CD, activity of acetoclastic methanogens as methanogenic consumed acetate (Cmeth, and CE and by measuring anolyte protein content to confirm a steady state condition. Controlling Cin from 35 to 1 mM resulted in tendency of both CD and Cmeth to decrease and CE to increase. At decreasing Cin from 35 to 5 mM which left excess acetate concentration in anolyte, the CEs were between 36.4% and 75.3%. At further decreasing Cin to 1 mM the acetate concentration was limited (Cef 0 mM, but the CE only reached 95.8%. Methanogenesis always occur and electrogens were not able to outcompete the acetoclastic methanogens even though the substrate concentration was limited.Keywords : microbial electrolysis cell, bio-hydrogen, metanogenesis, substrate concentration

  5. Space-time variability of alkalinity in the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    G. Cossarini

    2014-09-01

    Full Text Available The paper provides a basin assessment of the spatial distribution of ocean alkalinity in the Mediterranean Sea. The assessment is made using a 3-D transport-biogeochemical-carbonate model to integrate the available experimental findings, which also constrains model output. The results indicate that the Mediterranean Sea shows alkalinity values that are much higher than those observed in the Atlantic Ocean on a basin-wide scale. A marked west-to-east surface gradient of alkalinity is reproduced as a response to the terrestrial discharges, the mixing effect with the Atlantic water entering from the Gibraltar Strait and the Black Sea water from Dardanelles, and the surface flux of evaporation minus precipitation. Dense water production in marginal seas (Adriatic and Aegean Seas, where alkaline inputs are relevant, and the Mediterranean thermohaline circulation sustains the west-to-east gradient along the entire water column. In the surface layers, alkalinity has a relevant seasonal cycle (up to 40 μmol kg−1 that is driven both by physical and biological processes. A comparison of alkalinity vs. salinity indicates that different regions present different relationships. In regions of freshwater influence, the two measures are negatively correlated due to riverine alkalinity input, whereas they are positively correlated in open seas. Alkalinity always is much higher than in the Atlantic waters, which might indicate a higher than usual buffering capacity towards ocean acidification, even at high concentrations of dissolved inorganic carbon.

  6. Solar Power Augmented Electrolysis Module for Energy Storage Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Regenerative fuel cell systems often include a dedicated electrolysis module with solar photovoltaic (PV) panels packaged as a subsystem of the larger energy...

  7. Micro-electrolysis technology for industrial wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Experiments were conducted to study the role of micro-electrolysis in removing chromaticity and COD and improving the biodegradability of wastewater from pharmaceutical, dye-printing and papermaking plants. Results showed that the use of micro-electrolysis technology could remove more than 90% of chromaticity and more than 50% of COD and greatly improved the biodegradability of pharmaceutical wastewater. Lower initial pH could be advantageous to the removal of chromaticity. A retention time of 30 minutes was recommended for the process design of micro-electrolysis. For the use of micro-electrolysis in treatment of dye-printing wastewater, the removal rates of both chromaticity and COD were increased from neutral condition to acid condition for disperse blue wastewater; more than 90% of chromaticity and more than 50% of COD could be removed in neutral condition for vital red wastewater.

  8. Durability of Solid Oxide Electrolysis Cells for Syngas Production

    DEFF Research Database (Denmark)

    Sun, Xiufu; Chen, Ming; Liu, Yi-Lin; Hjalmarsson, Per; Ebbesen, Sune Dalgaard; Jensen, Søren Højgaard; Mogensen, Mogens Bjerg; Hendriksen, Peter Vang

    2013-01-01

    Performance and durability of Ni-YSZ supported solid oxide electrolysis cells (SOECs) for co-electrolysis of H2O and CO2 at high current density was investigated. The cells consist of a Ni-YSZ support, a Ni-YSZ electrode, a YSZ electrolyte, and an LSM-YSZ electrode. The durability was examined at...... 800°C and electrolysis current densities of −1 or −1.5 A/cm2 with 60% reactant (H2O + CO2) utilization. The cell voltage degradation showed a strong dependence on the electrolysis current density. Electrochemical characterization of the cells showed that the degradation was mainly related to the LSM...

  9. Large Scale Inert Anode for Molten Oxide Electrolysis Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Molten oxide electrolysis is a demonstrated laboratory-scale process for producing oxygen from the JSC-1a lunar simulant; however, critical subsystems necessary for...

  10. Synergistic Combination of Electrolysis and Electroporation for Tissue Ablation

    OpenAIRE

    Stehling, Michael K.; Guenther, Enric; Mikus, Paul; Klein, Nina; Rubinsky, Liel; Rubinsky, Boris

    2016-01-01

    Electrolysis, electrochemotherapy with reversible electroporation, nanosecond pulsed electric fields and irreversible electroporation are valuable non-thermal electricity based tissue ablation technologies. This paper reports results from the first large animal study of a new non-thermal tissue ablation technology that employs “Synergistic electrolysis and electroporation” (SEE). The goal of this pre-clinical study is to expand on earlier studies with small animals and use the pig liver to es...

  11. Advanced Water Purification System For In Situ Resource Utilization Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Prior to electrolysis, the water generated as an intermediate product must be treated to remove absorbed hydrochloric and hydrofluoric acids, byproducts derived...

  12. FIA-ISE联用技术测定工业锅炉水总碱度%Determination of the alkalinity in industrial boiler water by FIA-ISE method

    Institute of Scientific and Technical Information of China (English)

    康秀英; 邓宏康; 张伯先; 宋启军

    2011-01-01

    目前工业锅炉水的总碱度主要用指示剂法测定,但该方法费时,且不便于自动化.流动注射分析(FIA)技术具有快速、准确等特点,近几年来发展异常迅速.流动注射分析与离子选择性电极(ISE)联用技术用于测定溶液总碱度具有很好的效果.作者使用CN111型工业pH计与FIA联用技术测定了工业锅炉水中的总碱度并取得了满意的结果.该方法可实现对工业锅炉水总碱度的快速测定.%The alkalinity of industrial boiler water has mainly been determined by using acid base titration based on indicator method, but it is time consuming and not suitable for automation. Flow injection analysis (FIA) is a rapid,accurate and recently well-developed method. When the flow injection analysis coupled with an ion selective electrode is used for determining the alkalinity of the solution, pretty good effect can be obtained. When the industrial pH meter(CN 111 ) coupled with the FIA is used for determining the total alkalinity of boiler water, satisfactory result can be reached.

  13. Utilization of coal-derived pyrite by electrolysis

    Institute of Scientific and Technical Information of China (English)

    李登新; M.Makinot; 高晋生; 孟繁玲

    2001-01-01

    The utilization of coal-derived pyrite by electrolysis was studied. It is obvious that the sulfur and Fe in pyrite can be electrolyzed into Fe3+ and SO2-4, and the no pollutant is drained off. In this paper, the influence of conditions, including electrolysis potential, time, temperature, the acidity of electrolysis solutions, the concentration of adding agent, the concentration of pyrite, and the rate of conversion of pyrite (Cr) was investigated. Cr increases with the rise of potential, time, temperature, acidity and the concentration of additive agent, but decreases, with the rise of concentration of pyrite. At the certain conditions (at the potential of 3.0 V, temperature of 298 K, time of 12 h, the concentration of MnSO4 of 6%, concentration of pyrite of 4%, and concentration of acid of 10%), Cr is high to 93%. In the same time, the mechanism of electrolysis of pyrite was provided. The electrolysis of pyrite is actually the recycle of Mn ion between anodic surface and pyrite. At last, the production of FeSO4·7H2O through electrolysis of pyrite was introduced.

  14. A water film motor

    OpenAIRE

    Shirsavar, R.; Amjadi, A.; Radja, N. Hamedani; Niry, M. D.; Tabar, M. Reza Rahimi; Ejtehadi, M. R.

    2006-01-01

    We report on electrically-induced rotations in water films, which can function at many length scales. The device consists of a two-dimensional cell used for electrolysis of water films, as simple as an insulator frame with two electrodes on the sides, to which an external in-plane electric field perpendicular to the mean electrolysis current density is applied. If either the external field or the electrolysis current exceeds some threshold (while the other one is not zero), the liquid film be...

  15. High Temperature Electrolysis Pressurized Experiment Design, Operation, and Results

    Energy Technology Data Exchange (ETDEWEB)

    J.E. O' Brien; X. Zhang; G.K. Housley; K. DeWall; L. Moore-McAteer

    2012-09-01

    A new facility has been developed at the Idaho National Laboratory for pressurized testing of solid oxide electrolysis stacks. Pressurized operation is envisioned for large-scale hydrogen production plants, yielding higher overall efficiencies when the hydrogen product is to be delivered at elevated pressure for tank storage or pipelines. Pressurized operation also supports higher mass flow rates of the process gases with smaller components. The test stand can accommodate planar cells with dimensions up to 8.5 cm x 8.5 cm and stacks of up to 25 cells. It is also suitable for testing other cell and stack geometries including tubular cells. The pressure boundary for these tests is a water-cooled spool-piece pressure vessel designed for operation up to 5 MPa. Pressurized operation of a ten-cell internally manifolded solid oxide electrolysis stack has been successfully demonstrated up 1.5 MPa. The stack is internally manifolded and operates in cross-flow with an inverted-U flow pattern. Feed-throughs for gas inlets/outlets, power, and instrumentation are all located in the bottom flange. The entire spool piece, with the exception of the bottom flange, can be lifted to allow access to the internal furnace and test fixture. Lifting is accomplished with a motorized threaded drive mechanism attached to a rigid structural frame. Stack mechanical compression is accomplished using springs that are located inside of the pressure boundary, but outside of the hot zone. Initial stack heatup and performance characterization occurs at ambient pressure followed by lowering and sealing of the pressure vessel and subsequent pressurization. Pressure equalization between the anode and cathode sides of the cells and the stack surroundings is ensured by combining all of the process gases downstream of the stack. Steady pressure is maintained by means of a backpressure regulator and a digital pressure controller. A full description of the pressurized test apparatus is provided in this

  16. A Revisit to the Corrosion Inhibition of Aluminum in Aqueous Alkaline Solutions by Water-Soluble Alginates and Pectates as Anionic Polyelectrolyte Inhibitors

    Directory of Open Access Journals (Sweden)

    Refat Hassan

    2013-01-01

    Full Text Available The corrosion behavior of aluminum (Al in alkaline media in presence of some natural polymer inhibitors has been reinvestigated. The inhibition action of the tested inhibitors was found to obey both Langmuir and Freundlich isotherms models. The inhibition efficiency was found to increase with increasing the inhibitors concentration and decrease with increasing the temperature, suggesting physical adsorption mechanism. Factors such as the concentration and geometrical structure of the inhibitor, concentration of the corrosive medium, and temperature affecting the corrosion rates were examined. The kinetic parameters were evaluated, and a suitable corrosion mechanism consistent with the kinetic results obtained is suggested and discussed.

  17. Anodic dissolution of gold in alkaline solutions containing thiourea, thiosulfate and sulfite ions

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Gold dissolves electrochemically in alkaline solutions containing ligands to form complex ions with gold ion. Therefore, selective leaching of noble metals is expected without dissolution of base metals such as steels, aluminum alloys in scrap treatment. Gold electrodes were investigated using linear sweep voltammetry, EQCM method and potentiostatic electrolysis in alkaline solutions containing thiourea, Na2SO3 and Na2S2O3. The solution composition, electrode potential affect gold dissolution rate and current efficiency. The gold dissolved from anode electrode forms complex ions, suspension particles as compound precipitates and deposits on cathode electrode as a metal. Anodic efficiency for gold dissolution is between 10% and 22%. This is caused by the oxidation decomposition of sulfite ions and thiourea. The stability of the alkaline solution containing these elements was also estimated by capillary electrophoresis technique.

  18. Alkaline azide mutagenicity in cowpea

    International Nuclear Information System (INIS)

    Sodium azide is known as a potent mutagen in cereals and legumes. It is very effective in acidic medium in barley. Here an attempt is made to measure the effectiveness of sodium azide in alkaline medium (pH 7.4) on cowpea (Vigna unguiculata (L.) Walp., variety FS-68). Seeds pre-soaked in distilled water for 5 hours were treated with different concentrations (10-6, 10-5, 10-4 and 10-3M) of sodium azide (NaN3) for 4 hours at 28± 2 deg. C. Bottles were intermittently shaken, then the seeds were thoroughly washed in running tap water and subsequently planted in pots. The treatment caused significant biological damage such as reduction in seed germination, length of root and shoot, number of nodules and pods per plant and morphological leaf variations. Morphological, as well as chlorophyll mutants, were detected in M2

  19. 碱性离子水对降体重大鼠机体抗氧化能力影响%Influence of Alkaline Ionized Water on Losing Weight Rats' Organism Anti-oxidant Ability

    Institute of Scientific and Technical Information of China (English)

    张珍; 周文清

    2009-01-01

    We based Experiment of rat model of reduced weight, gave rats of reduced body weight Alkaline Ionized Water to drink;After testing Hb, Her,SOD, MDA, NO, GSH-Px, T-AOC and Using up each only big mouse movement the time which to the strength,we observes AIW to organism oxidation resistance ability and the motor function influence;we found that AIW can increase antioxidant capacity and exercise capacity of rat of reduced body weight.%实验建立大鼠降体重模型,给降体重大鼠饮用碱性离子水(Alkaline Ionized Water,AIW);测试血红蛋白(Hb)、血细胞压积(Hct)、红细胞过氧化物歧化酶(SOD)、血浆丙二醛(MDA)、血浆一氧化氮(NO)、全血谷胱甘肽过氧化物酶(GSH-Px)、全血总抗氧化能力(T-AOC)和每只大鼠运动至力竭的时间,来观察AIW对机体抗氧化能力及运动机能的影响;结果发现AIW可以提高降体重大鼠机体的抗氧化能力及运动能力.

  20. Systems Engineering Provides Successful High Temperature Steam Electrolysis Project

    Energy Technology Data Exchange (ETDEWEB)

    Charles V. Park; Emmanuel Ohene Opare, Jr.

    2011-06-01

    This paper describes two Systems Engineering Studies completed at the Idaho National Laboratory (INL) to support development of the High Temperature Stream Electrolysis (HTSE) process. HTSE produces hydrogen from water using nuclear power and was selected by the Department of Energy (DOE) for integration with the Next Generation Nuclear Plant (NGNP). The first study was a reliability, availability and maintainability (RAM) analysis to identify critical areas for technology development based on available information regarding expected component performance. An HTSE process baseline flowsheet at commercial scale was used as a basis. The NGNP project also established a process and capability to perform future RAM analyses. The analysis identified which components had the greatest impact on HTSE process availability and indicated that the HTSE process could achieve over 90% availability. The second study developed a series of life-cycle cost estimates for the various scale-ups required to demonstrate the HTSE process. Both studies were useful in identifying near- and long-term efforts necessary for successful HTSE process deployment. The size of demonstrations to support scale-up was refined, which is essential to estimate near- and long-term cost and schedule. The life-cycle funding profile, with high-level allocations, was identified as the program transitions from experiment scale R&D to engineering scale demonstration.

  1. Specific electrical conductivity in molten potassium dihydrogen phosphate KH2PO4 - An electrolyte for water electrolysis at ∼300°C

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey Valerievich; Berg, Rolf W.; Petrushina, Irina;

    2016-01-01

    temperature pressurized water electrolyzer demonstrating high conductivity of ∼0.30Scm-1 at 300°C. The conductivity data are given as polynomial functions of temperature and composition. The melting point of the pure salt under its own water vapor pressure was determined to be ∼272°C.......The conductivity of pure molten KH2PO4 salt and four mixtures with more or less water (KH2PO4-H2O and KH2PO4-KPO3 systems, respectively) were measured at temperatures of 240-320°C and under their own water vapor pressures. Molten KH2PO4 has been proven to be a promising electrolyte for an elevated...

  2. Sorption of water alkalinity and hardness from high-strength wastewater on bifunctional activated carbon: process optimization, kinetics and equilibrium studies.

    Science.gov (United States)

    Amosa, Mutiu K

    2016-08-01

    Sorption optimization and mechanism of hardness and alkalinity on bifunctional empty fruit bunch-based powdered activation carbon (PAC) were studied. The PAC possessed both high surface area and ion-exchange properties, and it was utilized in the treatment of biotreated palm oil mill effluent. Batch adsorption experiments designed with Design Expert(®) were conducted in correlating the singular and interactive effects of the three adsorption parameters: PAC dosage, agitation speed and contact time. The sorption trends of the two contaminants were sequentially assessed through a full factorial design with three factor interaction models and a central composite design with polynomial models of quadratic order. Analysis of variance revealed the significant factors on each design response with very high R(2) values indicating good agreement between model and experimental values. The optimum operating conditions of the two contaminants differed due to their different regions of operating interests, thus necessitating the utility of desirability factor to get consolidated optimum operation conditions. The equilibrium data for alkalinity and hardness sorption were better represented by the Langmuir isotherm, while the pseudo-second-order kinetic model described the adsorption rates and behavior better. It was concluded that chemisorption contributed majorly to the adsorption process. PMID:26752149

  3. 锅炉设备碱性腐蚀原因分析及水处理工艺改进%Analysis on the causes of boiler equipment alkaline corrosion and improvements on water treatment process

    Institute of Scientific and Technical Information of China (English)

    肖强; 霍文敏; 陆明

    2013-01-01

    锅炉的碱性腐蚀经常被人们所忽视,但其造成的后果往往是非常严重的,轻则造成爆管导致停产,重则会威胁到操作人员的人身安全.传统的锅炉水处理方法虽然价格低廉,但其存在先天的不足,在一定条件下无法阻止碱性腐蚀的发生.而近些年逐渐产生的锅炉水处理工艺及与其配套的有机锅炉水处理药剂则全方面改进了传统锅炉水处理方法的不足,并在现场应用中收到了良好的效果.%The problem of boiler equipment alkaline corrosion has always been neglected,resulting in serious consequence.It causes the burst of pipes leading to suspending operations,or threaten the safety of the operation staff.Although the price for traditional water treatment process is low,it has congenitally deficiency.It can not prevent the happening of alkaline corrosion under certain conditions.However,nowadays,some new boiler water treatment processes and organic boiler water treatment agents that go with the process can improve the deficiency of traditional boiler water treatment methods.It has been used in field application and received good effects.

  4. Reactions on carbon anodes in aluminium electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Eidet, Trygve

    1997-12-31

    The consumption of carbon anodes and energy in aluminium electrolysis is higher than what is required theoretically. This thesis studies the most important of the reactions that consume anode materials. These reactions are the electrochemical anode reaction and the airburn and carboxy reactions. The first part of the thesis deals with the kinetics and mechanism of the electrochemical anode reaction using electrochemical impedance spectroscopy. The second part deals with air and carboxy reactivity of carbon anodes and studies the effects of inorganic impurities on the reactivity of carbon anodes in the aluminium industry. Special attention is given to sulphur since its effect on the carbon gasification is not well understood. Sulphur is always present in anodes, and it is expected that the sulphur content of available anode cokes will increase in the future. It has also been suggested that sulphur poisons catalyzing impurities in the anodes. Other impurities that were investigated are iron, nickel and vanadium, which are common impurities in anodes which have been reported to catalyze carbon gasification. 88 refs., 92 figs., 24 tabs.

  5. Modeling Degradation in Solid Oxide Electrolysis Cells

    Energy Technology Data Exchange (ETDEWEB)

    Manohar S. Sohal; Anil V. Virkar; Sergey N. Rashkeev; Michael V. Glazoff

    2010-09-01

    Idaho National Laboratory has an ongoing project to generate hydrogen from steam using solid oxide electrolysis cells (SOECs). To accomplish this, technical and degradation issues associated with the SOECs will need to be addressed. This report covers various approaches being pursued to model degradation issues in SOECs. An electrochemical model for degradation of SOECs is presented. The model is based on concepts in local thermodynamic equilibrium in systems otherwise in global thermodynamic no equilibrium. It is shown that electronic conduction through the electrolyte, however small, must be taken into account for determining local oxygen chemical potential, , within the electrolyte. The within the electrolyte may lie out of bounds in relation to values at the electrodes in the electrolyzer mode. Under certain conditions, high pressures can develop in the electrolyte just near the oxygen electrode/electrolyte interface, leading to oxygen electrode delamination. These predictions are in accordance with the reported literature on the subject. Development of high pressures may be avoided by introducing some electronic conduction in the electrolyte. By combining equilibrium thermodynamics, no equilibrium (diffusion) modeling, and first-principles, atomic scale calculations were performed to understand the degradation mechanisms and provide practical recommendations on how to inhibit and/or completely mitigate them.

  6. Electrochemical processing of alkaline nitrate and nitrite wastes

    International Nuclear Information System (INIS)

    Processing of high-level waste at the Savannah River Plant (SRP) will produce, as a by-product, a low-level, alkaline salt solution containing approximately 17% sodium nitrate and sodium nitrite. This solution will be incorporated into a cement formulation, saltstone, and placed in an engineered landfill. Electrochemical methods have been investigated to decrease the nitrate and nitrite in this solution in order to lower the leaching of nitrate and nitrite from saltstone and to reduce the volume of saltstone. Laboratory experiments have demonstrated the technical feasibility of electrolytically reducing the nitrate and nitrite in a synthetic salt solution similar in composition to that expected to be produced at SRP. Greater than 99% of the sodium nitrate and sodium nitrite can be reduced, producing ammonia, nitrogen, oxygen, and sodium hydroxide. In addition, significant reductions in the volume of saltstone may be realized if the sodium hydroxide produced by electrolysis can be recycled

  7. Electrolytic denitrification of alkaline nitrate and nitrite solution

    International Nuclear Information System (INIS)

    Processing of high-level waste at the Savannah River Plant (SRP) will produce a low-level alkaline salt solution, containing approximately 17% sodium nitrate and sodium nitrite. This solution will be incorporated into a cement wasteform, saltstone, and placed in an engineered landfill. Laboratory experiments have demonstrated the technical feasibility of electrochemically reducing the nitrate and nitrite in a synthetic, nonradioactive salt solution similar in composition to that expected to be produced at SRP. Greater than ninety-five percent of the sodium nitrate and sodium nitrite can be reduced electrolytically, producing ammonia, nitrogen, oxygen, and sodium hydroxide. Reduction of the nitrate and nitrite will reduce the leaching of nitrate and nitrite from the saltstone monolith. In addition, significant reductions in the volume of saltstone may be realized if the sodium hydroxide produced by electrolysis can be recycled

  8. Electrochemical processing of alkaline nitrate and nitrite solutions

    International Nuclear Information System (INIS)

    Processing of high-level waste at the Savannah River Plant (SRP) will produce, as a by product, a low- level, alkaline salt solution containing approximately 17% sodium nitrate and sodium nitrite. This solution will be incorporated into a cement formulation, saltstone, and placed in an engineered landfill. Electrochemical methods have been investigated to decrease the nitrate and nitrite in this solution in order to lower the leaching of nitrate and nitrite from saltstone and to reduce the volume of saltstone. Laboratory experiments have demonstrated the technical feasibility of electrolytically reducing the nitrate and nitrite in a synthetic salt solution similar in composition to that expected to be produced at SRP. Greater than 99% of the sodium nitrate and sodium nitrite can be reduced, producing ammonia, nitrogen, oxygen, and sodium hydroxide. In addition, significant reductions in the volume of saltstone may be realized if the sodium hydroxide produced by electrolysis can be recycled

  9. Fabrication and characterization of oxide fine-mesh electrodes composed of Sb-SnO2 and study of oxygen evolution from the electrolysis of electrolyte-free water in a solid polymer electrolyte filter-press cell: Possibilities for the combustion of organic pollutants

    International Nuclear Information System (INIS)

    Highlights: • Fabrication of oxide fine-mesh electrodes composed of Sb-SnO2 for the application in solid polymer electrolyte cells. • Study of the oxygen evolution reaction during electrolysis of electrolyte-free water. • Overpotential for the OER and the electrode service life are both affected by the Sb content. - Abstract: Oxide fine-mesh electrodes composed of tin dioxide doped with antimony (OFM-Sb-SnO2) presenting different Sb contents were prepared using the thermal decomposition method on a stainless steel fine mesh support in order to obtain fluid-permeable anodes for applications in a solid polymer electrolyte filter-press cell. The surface and structural properties of the electrode materials were assessed by means of energy dispersive X-ray (EDS), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Electrochemical studies were carried out using cyclic voltammetry, polarizations curves and chronopotentiometry. A Nafion® 117 membrane was used as the only electrolyte for the studies using the filter-press cell. EDS data showed that the composition of the oxide films is quite different from the nominal composition evaluated from the precursor solutions. XRD spectra revealed that the presence of Sb can change the degree of crystallinity of the SnO2 phase (rutile structure). SEM images revealed a compact surface morphology of the oxide coatings containing some distributed rectangular grains. Voltammetric curves (VCs) obtained in electrolyte-free water revealed the electrochemically active surface area and the onset of the oxygen evolution reaction (OER) are both affected by the Sb content. Polarization curves obtained in electrolyte-free water revealed the overpotential for the OER increases with the Sb content. A comparative study using a 1.0 mol dm−3 H2SO4 solution revealed that the anion of the electrolyte affects the behaviour of VCs, as well as the Tafel plots for the OER. In addition, the Tafel plots are also affected by

  10. In-Situ Propellant Production on Mars: A Sabatier/Electrolysis Demonstration Plant

    Science.gov (United States)

    Clark, David L.

    1997-01-01

    An efficient, reliable propellant production plant has been developed for use on Mars. Using a Sabatier reactor in conjunction with a water electrolysis system, a complete demonstration plant has produced methane and liquid oxygen from simulated Martian atmosphere. The production plant has demonstrated high efficiency, extended duration production and autonomous operations. This paper presents the results and conclusions relating to eventual use in a Mars sample return mission. This work was funded by the Jet Propulsion Laboratory (JPL). The production plant was built and tested at the Propulsion Center of Lockheed Martin at the Denver Colorado facility.

  11. Generation of Hydrogen, Lignin and Sodium Hydroxide from Pulping Black Liquor by Electrolysis

    OpenAIRE

    Guangzai Nong; Zongwen Zhou; Shuangfei Wang

    2015-01-01

    Black liquor is generated in Kraft pulping of wood or non-wood raw material in pulp mills, and regarded as a renewable resource. The objective of this paper was to develop an effective means to remove the water pollutants by recovery of both lignin and sodium hydroxide from black liquor, based on electrolysis. The treatment of a 1000 mL of black liquor (122 g/L solid contents) consumed 345.6 kJ of electric energy, and led to the generation of 30.7 g of sodium hydroxide, 0.82 g of hydrogen gas...

  12. Continuous determination of the boiler water and industrial circulating cooling water pH value,alkalinity and chloride%锅炉水及工业循环冷却水的pH值、碱度和氯化物的连续测定

    Institute of Scientific and Technical Information of China (English)

    张居光; 吴继权; 黄容

    2013-01-01

    At automatic potentiometric titrator attached double electrodes, Using the direct potential and potentiometric titration methods, pH value, alkalinity and chloride concentration were obtained. pH combination electrode applies to the pH and alkalinity measured, and the reference pH electrode and indicator Ag electrode apply to precipitation titrated.The methods can be used for pH, alkalinity and chloride continuous determination of boiler water and industrial circulating cooling water. For high alkalinity and high chloride samples, the measured relative standard deviation is less than 0. 5%. For low alkalinity and chloride samples, the measured relative standard deviation is about 2%.%在双电极电位滴定仪上,应用直接电位法和电位滴定法依次获得pH值、碱度和氯化物浓度.pH复合电极不仅应用于pH值和碱度测定,还在沉淀滴定中发挥参比电极作用,银电极作为沉淀滴定的指示电极.该方法用于锅炉水和工业循环冷却水的pH值、碱度和氯化物连续的测定,对于碱度、氯化物浓度较高的样品,测定结果相对标准偏差小于0.5%.对于碱度、氯化物浓度较低的补水,测定结果的相对标准偏差约2%.

  13. Alkaline quinone flow battery.

    Science.gov (United States)

    Lin, Kaixiang; Chen, Qing; Gerhardt, Michael R; Tong, Liuchuan; Kim, Sang Bok; Eisenach, Louise; Valle, Alvaro W; Hardee, David; Gordon, Roy G; Aziz, Michael J; Marshak, Michael P

    2015-09-25

    Storage of photovoltaic and wind electricity in batteries could solve the mismatch problem between the intermittent supply of these renewable resources and variable demand. Flow batteries permit more economical long-duration discharge than solid-electrode batteries by using liquid electrolytes stored outside of the battery. We report an alkaline flow battery based on redox-active organic molecules that are composed entirely of Earth-abundant elements and are nontoxic, nonflammable, and safe for use in residential and commercial environments. The battery operates efficiently with high power density near room temperature. These results demonstrate the stability and performance of redox-active organic molecules in alkaline flow batteries, potentially enabling cost-effective stationary storage of renewable energy. PMID:26404834

  14. Alkaline broadening in Stars

    CERN Document Server

    De Kertanguy, A

    2015-01-01

    Giving new insight for line broadening theory for atoms with more structure than hydrogen in most stars. Using symbolic software to build precise wave functions corrected for ds;dp quantum defects. The profiles obtained with that approach, have peculiar trends, narrower than hydrogen, all quantum defects used are taken from atomic database topbase. Illustration of stronger effects of ions and electrons on the alkaline profiles, than neutral-neutral collision mechanism. Keywords : Stars: fundamental parameters - Atomic processes - Line: profiles.

  15. Alkaline quinone flow battery

    OpenAIRE

    Lin, Kaixiang; Chen, Qing; Gerhardt, Michael; Tong, Liuchuan; Kim, Sang Bok; Eisenach, Louise Ann; Valle, Alvaro West; Hardee, D.; Gordon, Roy Gerald; Aziz, Michael J.; Marshak, M

    2015-01-01

    Storage of photovoltaic and wind electricity in batteries could solve the mismatch problem between the intermittent supply of these renewable resources and variable demand. Flow batteries permit more economical long-duration discharge than solid-electrode batteries by using liquid electrolytes stored outside of the battery. We report an alkaline flow battery based on redox-active organic molecules that are composed entirely of Earth-abundant elements and are nontoxic, nonflammable, and safe f...

  16. Gadolinia-Doped Ceria Cathodes for Electrolysis of CO2

    Science.gov (United States)

    Adler, Stuart B.

    2009-01-01

    Gadolinia-doped ceria, or GDC, (Gd(0.4)Ce(0.6)O(2-delta), where the value of delta in this material varies, depending on the temperature and oxygen concentration in the atmosphere in which it is being used) has shown promise as a cathode material for high-temperature electrolysis of carbon dioxide in solid oxide electrolysis cells. The polarization resistance of a GDC electrode is significantly less than that of an otherwise equivalent electrode made of any of several other materials that are now in use or under consideration for use as cathodes for reduction of carbon dioxide. In addition, GDC shows no sign of deterioration under typical temperature and gas-mixture operating conditions of a high-temperature electrolyzer. Electrolysis of CO2 is of interest to NASA as a way of generating O2 from the CO2 in the Martian atmosphere. On Earth, a combination of electrolysis of CO2 and electrolysis of H2O might prove useful as a means of generating synthesis gas (syngas) from the exhaust gas of a coal- or natural-gas-fired power plant, thereby reducing the emission of CO2 into the atmosphere. The syngas a mixture of CO and H2 could be used as a raw material in the manufacture, via the Fisher-Tropsch process, of synthetic fuels, lubrication oils, and other hydrocarbon prod

  17. High Temperature Electrolysis using Electrode-Supported Cells

    International Nuclear Information System (INIS)

    An experimental study is under way to assess the performance of electrode-supported solid-oxide cells operating in the steam electrolysis mode for hydrogen production. The cells currently under study were developed primarily for the fuel cell mode of operation. Results presented in this paper were obtained from single cells, with an active area of 16 cm2 per cell. The electrolysis cells are electrode-supported, with yttria-stabilized zirconia (YSZ) electrolytes (∼10 (micro)m thick), nickel-YSZ steam/hydrogen electrodes (∼1400 (micro)m thick), and manganite (LSM) air-side electrodes (∼90 (micro)m thick). The purpose of the present study was to document and compare the performance and degradation rates of these cells in the fuel cell mode and in the electrolysis mode under various operating conditions. Initial performance was documented through a series of DC potential sweeps and AC impedance spectroscopy measurements. Degradation was determined through long-duration testing, first in the fuel cell mode, then in the electrolysis mode over more than 500 hours of operation. Results indicate accelerated degradation rates in the electrolysis mode compared to the fuel cell mode, possibly due to electrode delamination. The paper also includes details of the single-cell test apparatus developed specifically for these experiments.

  18. High Temperature Electrolysis using Electrode-Supported Cells

    Energy Technology Data Exchange (ETDEWEB)

    J. E. O' Brien; C. M. Stoots

    2010-07-01

    An experimental study is under way to assess the performance of electrode-supported solid-oxide cells operating in the steam electrolysis mode for hydrogen production. The cells currently under study were developed primarily for the fuel cell mode of operation. Results presented in this paper were obtained from single cells, with an active area of 16 cm2 per cell. The electrolysis cells are electrode-supported, with yttria-stabilized zirconia (YSZ) electrolytes (~10 µm thick), nickel-YSZ steam/hydrogen electrodes (~1400 µm thick), and manganite (LSM) air-side electrodes (~90 µm thick). The purpose of the present study was to document and compare the performance and degradation rates of these cells in the fuel cell mode and in the electrolysis mode under various operating conditions. Initial performance was documented through a series of DC potential sweeps and AC impedance spectroscopy measurements. Degradation was determined through long-duration testing, first in the fuel cell mode, then in the electrolysis mode over more than 500 hours of operation. Results indicate accelerated degradation rates in the electrolysis mode compared to the fuel cell mode, possibly due to electrode delamination. The paper also includes details of the single-cell test apparatus developed specifically for these experiments.

  19. 铝碳微电解处理含铜、镍电镀废水%Treatment of Electroplating Wastewater Containing Copper and Nickel by Micro-Electrolysis

    Institute of Scientific and Technical Information of China (English)

    刘东飞; 胡涓; 陈整生; 张志军

    2012-01-01

    通过铝碳微电解法对含铜、镍电镀废水进行处理,研究了铝碳比,反应时间,进水pH对处理效果的影响.结果表明,铝碳微电解最佳反应时间较铁碳微电解的30min提高到15min; Cu2+去除率较铁碳微电解由95%提高到98%,Ni2+去除率较铁碳微电解由94%提高到97%.这为铝碳微电解处理电镀废水的实际应用奠定了基础.%Substituting aluminum -carbon micro-electrolysis for iron-carbon micro - electrolysis for the treatment of copper, nickel in electroplating wastewater was studied. During the experiment, the effect of aluminum carbon ratio, reaction time, water pH on treatment was investigated . The results showed that the best reaction time of aluminum -carbon micro-electrolysis was 15min compared with the iron-carbon micro-electrolysis' 30min, the removal rate of Cu2+ and Ni2+was improved from 95% to 98% and 94% to 97%, respectively. This laid the foundation of practical application in electroplating wastewater treatment by aluminum-carbon micro-electrolysis.

  20. High temperature electrolysis of steam and carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Hoejgaard Jensen, Soeren [H.C. Oersted Institute, Copenhagen (Denmark); Hoegh, Jens V.T.; Barfod, Rasmus; Mogensen, Mogens [Risoe National Lab., Materials Research Dept., Roskilde (Denmark)

    2003-09-01

    The vision behind this work is establishment of methods for cheap production of hydrogen, H{sub 2}, and methane, CH{sub 4}, by electrolysis. CH{sub 4} is a particular suitable storage medium for renewable energy. Preliminary electrolysis experiments with a second generation of solid oxide fuel cells developed at Risoe National Laboratory, Denmark, show that these cells also have a high potential as solid oxide electrolyse cells. Furthermore, the experiments indicate that production of CH{sub 4} by high temperature electrolysis of mixtures of H{sub 2} and CO{sub 2} is possible using these cells, but very high gas pressure seems necessary to obtain acceptable yields. The results also indicate that much more research and development work is needed in order to make a sufficient durable electrolyse cell. (au)

  1. A Chronoamperometric Screen Printed Carbon Biosensor Based on Alkaline Phosphatase Inhibition for W(VI Determination in Water, Using 2-Phospho-l-Ascorbic Acid Trisodium Salt as a Substrate

    Directory of Open Access Journals (Sweden)

    Ana Lorena Alvarado-Gámez

    2015-01-01

    Full Text Available This paper presents a chronoamperometric method to determine tungsten in water using screen-printed carbon electrodes modified with gold nanoparticles and cross linked alkaline phosphatase immobilized in the working electrode. Enzymatic activity over 2-phospho-l-ascorbic acid trisodium salt, used as substrate, was affected by tungsten ions, which resulted in a decrease of chronoamperometric current, when a potential of 200 mV was applied on 10 mM of substrate in a Tris HCl buffer pH 8.00 and 0.36 M of KCl. Calibration curves for the electrochemical method validation, give a reproducibility of 5.2% (n = 3, a repeatability of 9.4% (n = 3 and a detection limit of 0.29 ± 0.01 µM. Enriched tap water, purified laboratory water and bottled drinking water, with a certified tungsten reference solution traceable to NIST, gave a recovery of 97.1%, 99.1% and 99.1% respectively (n = 4 in each case and a dynamic range from 0.6 to 30 µM. This study was performed by means of a Lineweaver–Burk plot, showing a mixed kinetic inhibition.

  2. Power to fuel using electrolysis and CO2 capture

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Graves, Christopher R.; Chatzichristodoulou, Christodoulos;

    2014-01-01

    ” hydrocarbon fuels seem particularlybenign to replace the fossil fuels, and electrolysis seems to be a feasible step in production of green fuels. In particular, synthetic hydrocarbon based fuel will be necessary for the heavy transportation vehicles such as airplanes, ships, and trucks. More than 65 % of the......Conversion of renewable electricity to synthetic fuel using electrolysis to produce at H2 and CO, which is furtherused to form liquid or gaseous fuel, called “power to fuel” or “power2fuel” has got a lot of attention recently.This is because synthetic fuels (synfuels) in the form CO2 neutral “green...... large scale fuel production....

  3. Electrochemical disinfection of toilet wastewater using wastewater electrolysis cell.

    Science.gov (United States)

    Huang, Xiao; Qu, Yan; Cid, Clément A; Finke, Cody; Hoffmann, Michael R; Lim, Keahying; Jiang, Sunny C

    2016-04-01

    The paucity of proper sanitation facilities has contributed to the spread of waterborne diseases in many developing countries. The primary goal of this study was to demonstrate the feasibility of using a wastewater electrolysis cell (WEC) for toilet wastewater disinfection. The treated wastewater was designed to reuse for toilet flushing and agricultural irrigation. Laboratory-scale electrochemical (EC) disinfection experiments were performed to investigate the disinfection efficiency of the WEC with four seeded microorganisms (Escherichia coli, Enterococcus, recombinant adenovirus serotype 5, and bacteriophage MS2). In addition, the formation of organic disinfection byproducts (DBPs) trihalomethanes (THMs) and haloacetic acids (HAA5) at the end of the EC treatment was also investigated. The results showed that at an applied cell voltage of +4 V, the WEC achieved 5-log10 reductions of all four seeded microorganisms in real toilet wastewater within 60 min. In contrast, chemical chlorination (CC) disinfection using hypochlorite [NaClO] was only effective for the inactivation of bacteria. Due to the rapid formation of chloramines, less than 0.5-log10 reduction of MS2 was observed in toilet wastewater even at the highest [NaClO] dosage (36 mg/L, as Cl2) over a 1 h reaction. Experiments using laboratory model waters showed that free reactive chlorine generated in situ during EC disinfection process was the main disinfectant responsible for the inactivation of microorganisms. However, the production of hydroxyl radicals [OH], and other reactive oxygen species by the active bismuth-doped TiO2 anode were negligible under the same electrolytic conditions. The formation of THMs and HAA5 were found to increase with higher applied cell voltage. Based on the energy consumption estimates, the WEC system can be operated using solar energy stored in a DC battery as the sole power source. PMID:26854604

  4. Fusion reactors-high temperature electrolysis (HTE)

    International Nuclear Information System (INIS)

    Results of a study to identify and develop a reference design for synfuel production based on fusion reactors are given. The most promising option for hydrogen production was high-temperature electrolysis (HTE). The main findings of this study are: 1. HTE has the highest potential efficiency for production of synfuels from fusion; a fusion to hydrogen energy efficiency of about 70% appears possible with 18000C HTE units and 60% power cycle efficiency; an efficiency of about 50% possible with 14000C HTE units and 40% power cycle efficiency. 2. Relative to thermochemical or direct decomposition methods HTE technology is in a more advanced state of development, 3. Thermochemical or direct decomposition methods must have lower unit process or capital costs if they are to be more attractive than HTE. 4. While design efforts are required, HTE units offer the potential to be quickly run in reverse as fuel cells to produce electricity for restart of Tokamaks and/or provide spinning reserve for a grid system. 5. Because of the short timescale of the study, no detailed economic evaluation could be carried out.A comparison of costs could be made by employing certain assumptions. For example, if the fusion reactor-electrolyzer capital installation is $400/(KW(T) [$1000/KW(E) equivalent], the H2 energy production cost for a high efficiency (about 70 %) fusion-HTE system is on the same order of magnitude as a coal based SNG plant based on 1976 dollars. 6. The present reference design indicates that a 2000 MW(th) fusion reactor could produce as much at 364 x 106 scf/day of hydrogen which is equivalent in heating value to 20,000 barrels/day of gasoline. This would fuel about 500,000 autos based on average driving patterns. 7. A factor of three reduction in coal feed (tons/day) could be achieved for syngas production if hydrogen from a fusion-HTE system were used to gasify coal, as compared to a conventional syngas plant using coal-derived hydrogen

  5. An exergetic/energetic/economic analysis of three hydrogen production processes - Electrolysis, hybrid, and thermochemical

    Science.gov (United States)

    Funk, J. E.; Eisermann, W.

    This paper presents the results of a combined first and second law analysis, along with capital and operating costs, for hydrogen production from water by means of electrolytic, hybrid, and thermochemical processes. The processes are SPE and Lurgi electrolysis with light water reactor power generation and sulfur cycle hybrid, thermochemical and SPE electrolysis with a very high temperature reactor primary energy source. Energy and Exergy (2nd law) flow diagrams for the process are shown along with the location and magnitude of the process irreversibilities. The overall process thermal (1st law) efficiencies vary from 25 to 51% and the exergetic (2nd law) efficiencies, referred to the fuel for the primary energy source, vary from 22 to 45%. Capital and operating costs, escalated to 1979 dollars, are shown for each process for both the primary energy source and the hydrogen production plant. All costs were taken from information available in the open literature and are for a plant capacity of 100 x 10 to the 6th SCF/day. Production costs vary from 10 to 18 $/GJ, based on the higher heating value of hydrogen, and are based on a 90% plant operating factor with a 21% annual charge on total capital costs.

  6. Versatile fuel cleanup system based on palladium permeation and vapor electrolysis

    International Nuclear Information System (INIS)

    Some variations and extensions of a Fuel Cleanup System based on the combination of palladium diffuser and a vapor electrolysis cell were studied to improve the flexibility to accept broader range of flow rate, gas contents and operation modes. Processing of inert gas - CH4, H2, He2O mixtures in a closed loop showed satisfactory detritiation, with the processing of methane by catalytic steam reforming and oxidation, and electrolytic oxidation. The decomposition of hydrocarbon on the anode side of the ceramic electrolysis cell was tested to study the feasibility as an oxidizer. The zirconia ceramic membrane with Pt electrode are tested with methane at the anode for oxidation, and water vapor on the cathode for reduction. The cell converted methane to carbon dioxide and vapor with high efficiency and simultaneously decomposed water vapor to hydrogen. This application of the cell simplifies the process, and eliminates the use of catalyst and oxygen gas. A versatile fuel cleanup that eliminates most of previous concerns and improves the performance is proposed. 7 refs., 5 figs., 1 tab

  7. Alkaline Phosphatase in Stem Cells

    Directory of Open Access Journals (Sweden)

    Kateřina Štefková

    2015-01-01

    Full Text Available Alkaline phosphatase is an enzyme commonly expressed in almost all living organisms. In humans and other mammals, determinations of the expression and activity of alkaline phosphatase have frequently been used for cell determination in developmental studies and/or within clinical trials. Alkaline phosphatase also seems to be one of the key markers in the identification of pluripotent embryonic stem as well as related cells. However, alkaline phosphatases exist in some isoenzymes and isoforms, which have tissue specific expressions and functions. Here, the role of alkaline phosphatase as a stem cell marker is discussed in detail. First, we briefly summarize contemporary knowledge of mammalian alkaline phosphatases in general. Second, we focus on the known facts of its role in and potential significance for the identification of stem cells.

  8. A Control Strategy for Photovoltaic-Solid Polymer Electrolysis System Based on Surface Temperature of PV Panel

    Directory of Open Access Journals (Sweden)

    Riza Muhida

    2008-01-01

    Full Text Available Processes to produce hydrogen from solar photovoltaic powered water electrolysis using solid polymer electrolysis are reported. An alternative control of maximum power point tracking method based on analysis of PV panel’s surface Temperature for the PV-SPE system was designed and implemented. From this analysis an optimal voltage of PV can be obtained and was realized as a reference voltage of Dc-DC converter. By maintenance the output voltage of PV using the reference voltage control, the output PV can be optimized at its MPP operation. The MPPT performance and hydrogen production performance of this method have been evaluated and discussed based on the results of the experiment.

  9. Ammonia synthesis. Ammonia synthesis by N₂ and steam electrolysis in molten hydroxide suspensions of nanoscale Fe₂O₃.

    Science.gov (United States)

    Licht, Stuart; Cui, Baochen; Wang, Baohui; Li, Fang-Fang; Lau, Jason; Liu, Shuzhi

    2014-08-01

    The Haber-Bosch process to produce ammonia for fertilizer currently relies on carbon-intensive steam reforming of methane as a hydrogen source. We present an electrochemical pathway in which ammonia is produced by electrolysis of air and steam in a molten hydroxide suspension of nano-Fe2O3. At 200°C in an electrolyte with a molar ratio of 0.5 NaOH/0.5 KOH, ammonia is produced at 1.2 volts (V) under 2 milliamperes per centimeter squared (mA cm(-2)) of applied current at coulombic efficiency of 35% (35% of the applied current results in the six-electron conversion of N2 and water to ammonia, and excess H2 is cogenerated with the ammonia). At 250°C and 25 bar of steam pressure, the electrolysis voltage necessary for 2 mA cm(-2) current density decreased to 1.0 V. PMID:25104378

  10. Alkaline fuel cells applications

    Science.gov (United States)

    Kordesch, Karl; Hacker, Viktor; Gsellmann, Josef; Cifrain, Martin; Faleschini, Gottfried; Enzinger, Peter; Fankhauser, Robert; Ortner, Markus; Muhr, Michael; Aronson, Robert R.

    On the world-wide automobile market technical developments are increasingly determined by the dramatic restriction on emissions as well as the regimentation of fuel consumption by legislation. Therefore there is an increasing chance of a completely new technology breakthrough if it offers new opportunities, meeting the requirements of resource preservation and emission restrictions. Fuel cell technology offers the possibility to excel in today's motive power techniques in terms of environmental compatibility, consumer's profit, costs of maintenance and efficiency. The key question is economy. This will be decided by the costs of fuel cell systems if they are to be used as power generators for future electric vehicles. The alkaline hydrogen-air fuel cell system with circulating KOH electrolyte and low-cost catalysed carbon electrodes could be a promising alternative. Based on the experiences of Kordesch [K. Kordesch, Brennstoffbatterien, Springer, Wien, 1984, ISBN 3-387-81819-7; K. Kordesch, City car with H 2-air fuel cell and lead-battery, SAE Paper No. 719015, 6th IECEC, 1971], who operated a city car hybrid vehicle on public roads for 3 years in the early 1970s, improved air electrodes plus new variations of the bipolar stack assembly developed in Graz are investigated. Primary fuel choice will be a major issue until such time as cost-effective, on-board hydrogen storage is developed. Ammonia is an interesting option. The whole system, ammonia dissociator plus alkaline fuel cell (AFC), is characterised by a simple design and high efficiency.

  11. Preparation of Mg-Li alloys by electrolysis in molten salt at low temperature

    Institute of Scientific and Technical Information of China (English)

    Mi Lin Zhang; Yong De Yan; Zhi Yao Hou; Lu An Fan; Zeng Chen; Ding Xiang Tang

    2007-01-01

    A new technology for preparation of low cost Mg-Li alloys was studied. The alloys were prepared by electrolysis in molten were investigated, and optimal electrolysis parameters were obtained. Mg-Li alloys with low lithium content (about 25%) were prepared by the unique method of a higher post-thermal treatment temperature after electrolysis at low temperature. The results showed that the electrolysis can be carried out at low temperature, which resulted in reducing preparation cost due to energy saving.The new technology for the preparation of Mg-Li alloy by electrolysis in molten salt was proved to be feasible.

  12. Nitrogen removal efficiency of iron-carbon micro-electrolysis system treating high nitrate nitrogen organic pharmaceutical wastewater

    Institute of Scientific and Technical Information of China (English)

    周健; 段送华; 陈垚; 胡斌

    2009-01-01

    The nitrate nitrogen removal efficiency of iron-carbon micro-electrolysis system was discussed in treating pharmaceutical wastewater with high nitrogen and refractory organic concentration. The results show that the granularity of fillings,pH,volume ratios of iron-carbon and gas-water,and HRT. have significant effects on the nitrogen removal efficiency of iron-carbon micro-electrolysis system. The iron-carbon micro-electrolysis system has a good removal efficiency of pharmaceutical wastewater with high nitrogen and refractory organic concentration when the influent TN,NH4+-N,NO3--N and BOD5/CODCr are 823 mg/L,30 mg/L,793 mg/L and 0.1,respectively,at the granularity of iron and carbon 0.425 mm,pH 3,iron-carbon ratio 3,gas-water ratio 5,HRT 1.5 h,and the removal rates of TN,NH4+-N and NO3--N achieve 51.5%,70% and 50.94%,respectively.

  13. Reactive-transport model analyses of bentonite alteration behavior at alkaline condition generated by cement-water interaction in a TRU wastes repository

    International Nuclear Information System (INIS)

    The maximum dose of ionizing radiation from the geological disposal of TRU wastes will likely be controlled by poorly sorbing soluble radionuclides, such as I-129. Proposed repository designs for the geological disposal of TRU wastes envisage the use of an engineered barrier composed of a bentonite buffer to limit the migration of such radionuclides by impeding groundwater flow. Cementitious materials will inevitably be used for waste packaging, infilling and adding structural integrity to the repository. Using cementitious materials, however, is problematic because they produce highly alkaline leachates which have the potential to cause a complex series of coupled changes in the porewater chemistry, mineralogy and, ultimately, the mass transport properties of the bentonite buffer. To elucidate the consequences of these coupled changes, reactive-transport model analyses have been conducted for bentonite alteration test cases with the use of different combinations of secondary minerals that will likely form in the bentonite buffer. A dissolution rate equation of smectite (a key component of bentonite) applicable to pH 7-13 and 25-80degC was proposed and used in the reactive-transport model analyses. It was found that the amount of dissolved smectite at the center of the bentonite buffer was smaller and those in the vicinity of the cement interface was larger when thermodynamically metastable secondary minerals mainly precipitated as compared with the precipitation of stable phases. The calculated temporal and spatial changes of kinetic smectite dissolution were interpreted as a consequence of the changes in Gibbs free energy and porewater chemistry. Furthermore, the bentonite porewater chemistry was also affected by the stoichiometry and thermodynamic stability of the secondary minerals and the kinetics of smectite dissolution. Except in the close proximity of the cement interface, it was found that regardless of the choice of secondary minerals, the effective

  14. Principle and perspectives of hydrogen production through biocatalyzed electrolysis

    NARCIS (Netherlands)

    Rozendal, R.A.; Hamelers, H.V.M.; Euverink, G.J.W.; Metz, S.J.; Buisman, C.J.N.

    2006-01-01

    Biocatalyzed electrolysis is a novel biological hydrogen production process with the potential to efficiently convert a wide range of dissolved organic materials in wastewaters. Even substrates formerly regarded to be unsuitable for hydrogen production due to the endothermic nature of the involved c

  15. Manufacturing of A micro probe using supersonic aided electrolysis process

    CERN Document Server

    Shyu, R F; Ho, Chi-Ting

    2008-01-01

    In this paper, a practical micromachining technology was applied for the fabrication of a micro probe using a complex nontraditional machining process. A series process was combined to machine tungsten carbide rods from original dimension. The original dimension of tungsten carbide rods was 3mm ; the rods were ground to a fixed-dimension of 50 micrometers using precision grinding machine in first step. And then, the rod could be machined to a middle-dimension of 20 micrometers by electrolysis. A final desired micro dimension can be achieved using supersonic aided electrolysis. High-aspect-ratio of micro tungsten carbide rod was easily obtained by this process. Surface roughness of the sample with supersonic aided agitation was compared with that with no agitation in electrolysis. The machined surface of the sample is very smooth due to ionized particles of anode could be removed by supersonic aided agitation during electrolysis. Deep micro holes can also be achieved by the machined high-aspect-rati tungsten c...

  16. Production of Hydrogen and Synthesis Gas by High Temperature Electrolysis

    DEFF Research Database (Denmark)

    Ebbesen, Sune; Høgh, Jens Valdemar Thorvald; Mogensen, Mogens Bjerg

    2009-01-01

    electrolysis cells was found to be influenced by the adsorption of impurities from the gasses, whereas the application of chromium containing interconnect plates and glass sealings do not seem to influence the durability. Cleaning the inlet gasses to the Ni/YSZ electrode resulted in operation without any long...

  17. Study on hydrogen production by high temperature electrolysis of steam

    International Nuclear Information System (INIS)

    In JAERI, design and R and D works on hydrogen production process have been conducted for connecting to the HTTR under construction at the Oarai Research Establishment of JAERI as a nuclear heat utilization system. As for a hydrogen production process by high-temperature electrolysis of steam, laboratory-scale experiments were carried out with a practical electrolysis tube with 12 cells connected in series. Hydrogen was produced at a maximum density of 44 Nml/cm2h at 950degC, and know-how of operational procedures and operational experience were also accumulated. Thereafter, a planar electrolysis cell supported by a metallic plate was fabricated in order to improve hydrogen production performance and durability against thermal cycles. In the preliminary test with the planar cell, hydrogen has been produced continuously at a maximum density of 33.6 Nml/cm2h at an electrolysis temperature of 950degC. This report presents typical test results mentioned above, a review of previous studies conducted in the world and R and D items required for connecting to the HTTR. (author)

  18. Hydrogen production from high temperature electrolysis and fusion reactor

    International Nuclear Information System (INIS)

    Production of hydrogen from high temperature electrolysis of steam coupled with a fusion reactor is studied. The process includes three major components: the fusion reactor, the high temperature electrolyzer and the power conversion cycle each of which is discussed in the paper. Detailed process design and analysis of the system is examined. A parametric study on the effect of process efficiency is presented

  19. PEM Electrolysis H2A Production Case Study Documentation

    Energy Technology Data Exchange (ETDEWEB)

    James, Brian [Strategic Analysis Inc. (SA), Arlington, Virginia; Colella, Whitney [Strategic Analysis Inc. (SA), Arlington, Virginia; Moton, Jennie [Strategic Analysis Inc. (SA), Arlington, Virginia; Saur, G. [Strategic Analysis Inc. (SA), Arlington, Virginia; Ramsden, T. [Strategic Analysis Inc. (SA), Arlington, Virginia

    2013-12-31

    This report documents the development of four DOE Hydrogen Analysis (H2A) case studies for polymer electrolyte membrane (PEM) electrolysis. The four cases characterize PEM electrolyzer technology for two hydrogen production plant sizes (Forecourt and Central) and for two technology development time horizons (Current and Future).

  20. Synergistic Combination of Electrolysis and Electroporation for Tissue Ablation.

    Science.gov (United States)

    Stehling, Michael K; Guenther, Enric; Mikus, Paul; Klein, Nina; Rubinsky, Liel; Rubinsky, Boris

    2016-01-01

    Electrolysis, electrochemotherapy with reversible electroporation, nanosecond pulsed electric fields and irreversible electroporation are valuable non-thermal electricity based tissue ablation technologies. This paper reports results from the first large animal study of a new non-thermal tissue ablation technology that employs "Synergistic electrolysis and electroporation" (SEE). The goal of this pre-clinical study is to expand on earlier studies with small animals and use the pig liver to establish SEE treatment parameters of clinical utility. We examined two SEE methods. One of the methods employs multiple electrochemotherapy-type reversible electroporation magnitude pulses, designed in such a way that the charge delivered during the electroporation pulses generates the electrolytic products. The second SEE method combines the delivery of a small number of electrochemotherapy magnitude electroporation pulses with a low voltage electrolysis generating DC current in three different ways. We show that both methods can produce lesion with dimensions of clinical utility, without the need to inject drugs as in electrochemotherapy, faster than with conventional electrolysis and with lower electric fields than irreversible electroporation and nanosecond pulsed ablation. PMID:26866693

  1. Synergistic Combination of Electrolysis and Electroporation for Tissue Ablation.

    Directory of Open Access Journals (Sweden)

    Michael K Stehling

    Full Text Available Electrolysis, electrochemotherapy with reversible electroporation, nanosecond pulsed electric fields and irreversible electroporation are valuable non-thermal electricity based tissue ablation technologies. This paper reports results from the first large animal study of a new non-thermal tissue ablation technology that employs "Synergistic electrolysis and electroporation" (SEE. The goal of this pre-clinical study is to expand on earlier studies with small animals and use the pig liver to establish SEE treatment parameters of clinical utility. We examined two SEE methods. One of the methods employs multiple electrochemotherapy-type reversible electroporation magnitude pulses, designed in such a way that the charge delivered during the electroporation pulses generates the electrolytic products. The second SEE method combines the delivery of a small number of electrochemotherapy magnitude electroporation pulses with a low voltage electrolysis generating DC current in three different ways. We show that both methods can produce lesion with dimensions of clinical utility, without the need to inject drugs as in electrochemotherapy, faster than with conventional electrolysis and with lower electric fields than irreversible electroporation and nanosecond pulsed ablation.

  2. Durability of solid oxide electrolysis cells for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Hauch, A.; Hoejgaard Jensen, S.; Dalgaard Ebbesen, S.

    2007-05-15

    In the perspective of the increasing interest in renewable energy and hydrogen economy, the reversible solid oxide cells (SOCs) is a promising technology as it has the potential of providing efficient and cost effective hydrogen production by high temperature electrolysis of steam (HTES). Furthermore development of such electrolysis cells can gain from the results obtained within the R and D of SOFCs. For solid oxide electrolysis cells (SOEC) to become interesting from a technological point of view, cells that are reproducible, high performing and long-term stable need to be developed. In this paper we address some of the perspectives of the SOEC technology i.e. issues such as a potential H2 production price as low as 0.71 US dollar/kg H{sub 2} using SOECs for HTES; is there a possible market for the electrolysers? and what R and D steps are needed for the realisation of the SOEC technology? In the experimental part we present electrolysis test results on SOCs that have been optimized for fuel cell operation but applied for HTES. The SOCs are produced on a pre-pilot scale at Risoe National Laboratory. These cells have been shown to have excellent initial electrolysis performance, but the durability of such electrolysis cells are not optimal and examples of results from SOEC tests over several hundreds of hours are given here. The long-term tests have been run at current densities of -0.5 A/cm{sup 2} and -1 A/cm{sup 2}, temperatures of 850 deg. C and 950 deg. C and p(H{sub 2}O)/p(H{sub 2}) of 0.5/0.5 and 0.9/0.1. Long-term degradation rates are shown to be up to 5 times higher for SOECs compared to similar SOFC testing. Furthermore, hydrogen and synthetic fuel production prices are calculated using the experimental results from long-term electrolysis test as input and a short outlook for the future work on SOECs will be given as well. (au)

  3. HIGH-TEMPERATURE CO-ELECTROLYSIS OF H2O AND CO2 FOR SYNGAS PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Stoots, C.M.

    2006-11-01

    Worldwide, the demand for light hydrocarbon fuels like gasoline and diesel oil is increasing. To satisfy this demand, oil companies have begun to utilize oil deposits of lower hydrogen content (an example is the Athabasca Oil Sands). Additionally, the higher contents of sulfur and nitrogen of these resources requires processes such as hydrotreating to meet environmental requirements. In the mean time, with the price of oil currently over $50 / barrel, synthetically-derived hydrocarbon fuels (synfuels) have become economical. Synfuels are typically produced from syngas – hydrogen (H2) and carbon monoxide (CO) -- using the Fischer-Tropsch process, discovered by Germany before World War II. South Africa has used synfuels to power a significant number of their buses, trucks, and taxicabs. The Idaho National Laboratory (INL), in conjunction with Ceramatec Inc. (Salt Lake City, USA) has been researching for several years the use of solid-oxide fuel cell technology to electrolyze steam for large-scale nuclear-powered hydrogen production. Now, an experimental research project is underway at the INL to investigate the feasibility of producing syngas by simultaneously electrolyzing at high-temperature steam and carbon dioxide (CO2) using solid oxide fuel cell technology. The syngas can then be used for synthetic fuel production. This program is a combination of experimental and computational activities. Since the solid oxide electrolyte material is a conductor of oxygen ions, CO can be produced by electrolyzing CO2 sequestered from some greenhouse gas-emitting process. Under certain conditions, however, CO can further electrolyze to produce carbon, which can then deposit on cell surfaces and reduce cell performance. The understanding of the co-electrolysis of steam and CO2 is also complicated by the competing water-gas shift reaction. Results of experiments and calculations to date of CO2 and CO2/H2O electrolysis will be presented and discussed. These will include

  4. HYDROGEN GENERATION FROM ELECTROLYSIS - REVISED FINAL TECHNICAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    IBRAHIM, SAMIR; STICHTER, MICHAEL

    2008-07-31

    DOE GO13028-0001 DESCRIPTION/ABSTRACT This report is a summary of the work performed by Teledyne Energy Systems to understand high pressure electrolysis mechanisms, investigate and address safety concerns related to high pressure electrolysis, develop methods to test components and systems of a high pressure electrolyzer, and produce design specifications for a low cost high pressure electrolysis system using lessons learned throughout the project. Included in this report are data on separator materials, electrode materials, structural cell design, and dissolved gas tests. Also included are the results of trade studies for active area, component design analysis, high pressure hydrogen/oxygen reactions, and control systems design. Several key pieces of a high pressure electrolysis system were investigated in this project and the results will be useful in further attempts at high pressure and/or low cost hydrogen generator projects. An important portion of the testing and research performed in this study are the safety issues that are present in a high pressure electrolyzer system and that they can not easily be simplified to a level where units can be manufactured at the cost goals specified, or operated by other than trained personnel in a well safeguarded environment. The two key objectives of the program were to develop a system to supply hydrogen at a rate of at least 10,000 scf/day at a pressure of 5000psi, and to meet cost goals of $600/ kW in production quantities of 10,000/year. On these two points TESI was not successful. The project was halted due to concerns over safety of high pressure gas electrolysis and the associated costs of a system which reduced the safety concerns.

  5. Operating experience of the experimental industrial plant for reprocessing of tritiated water wastes

    International Nuclear Information System (INIS)

    The results of 5-year operation of the experimental industrial plant for hydrogen isotope separation using combined electrolysis and catalytic exchange (CECE) process are presented. The plant is used for large-scale studies of CECE process and for reprocessing tritiated heavy water wastes. The main parts of the plant are a 100-mm diameter exchange column of 6.9 m overall height, alkaline electrolytic cells and catalytic burners. The separation performance of the column was determined. The computer code makes it possible to carry out the calculation over a wide range of conditions and to forecast a concentration profile within the column when the values of flow rates are changed. The experience gained during the plant operation shows a high efficiency of isotope separation by CECE process and allows regarding CECE process as a considerable promise for the industrial use, in particular, for water purification from tritium

  6. Bifunctional alkaline oxygen electrodes

    Science.gov (United States)

    Swette, L.; Kackley, N.; Mccatty, S. A.

    1991-01-01

    The authors describe the identification and testing of electrocatalysts and supports for the positive electrode of moderate-temperature, single-unit, rechargeable alkaline fuel cells. Recent work on Na(x)Pt3O4, a potential bifunctional catalyst, is described, as well as the application of novel approaches to the development of more efficient bifunctional electrode structures. The three dual-character electrodes considered here showed similar superior performance; the Pt/RhO2 and Rh/RhO2 electrodes showed slightly better performance than the Pt/IrO2 electrode. It is concluded that Na(x)Pt3O4 continues to be a promising bifunctional oxygen electrode catalyst but requires further investigation and development.

  7. Nitrate removal and microbial analysis by combined micro-electrolysis and autotrophic denitrification.

    Science.gov (United States)

    Xing, Wei; Li, Desheng; Li, Jinlong; Hu, Qianyi; Deng, Shihai

    2016-07-01

    A process combining micro-electrolysis and autotrophic denitrification (CEAD) with iron-carbon micro-electrolysis carriers was developed for nitrate removal. The process was performed using organic-free influent with a NO3(-)-N concentration of 40.0±3.0mg/L and provided an average nitrate removal efficiency of 95% in stable stages. The total nitrogen removal efficiency reached 75%, with 21% of NO3(-)-N converted into NH4(+)-N. The corresponding hydraulic retention time was 8-10h, and the optimal pH ranged from 8.5 to 9.5. Microbial analysis with high-throughput sequencing revealed that dominant microorganisms in the reactor belonged to the classes of β-, γ-, and α-Proteobacteria. The abundance of the genera Thermomonas significantly increased during the operation, comprising 21.4% and 24.1% in sludge attached to the carriers in the middle and at the bottom of the reactor, respectively. The developed CEAD achieved efficient nitrate removal from water without organics, which is suitable for practical application. PMID:27019127

  8. Generation of Hydrogen, Lignin and Sodium Hydroxide from Pulping Black Liquor by Electrolysis

    Directory of Open Access Journals (Sweden)

    Guangzai Nong

    2015-12-01

    Full Text Available Black liquor is generated in Kraft pulping of wood or non-wood raw material in pulp mills, and regarded as a renewable resource. The objective of this paper was to develop an effective means to remove the water pollutants by recovery of both lignin and sodium hydroxide from black liquor, based on electrolysis. The treatment of a 1000 mL of black liquor (122 g/L solid contents consumed 345.6 kJ of electric energy, and led to the generation of 30.7 g of sodium hydroxide, 0.82 g of hydrogen gas and 52.1 g of biomass solids. Therefore, the recovery ratios of elemental sodium and biomass solids are 80.4% and 76%, respectively. Treating black liquor by electrolysis is an environmentally friendly technology that can, in particular, be an alternative process in addressing the environmental issues of pulping waste liquor to the small-scale mills without black liquor recovery.

  9. Heterotrophic microflora of highly alkaline (pH > 13) brown mud disposal site drainage water near Ziar nad Hronom (Banska Bystrica region, Slovakia).

    Science.gov (United States)

    Stramova, Zuzana; Remenar, Matej; Javorsky, Peter; Pristas, Peter

    2016-03-01

    Brown mud is a waste by-product of alumina production by Bayer process. Due to extensive sodium hydroxide use in the process, brown mud disposal site near Ziar nad Hronom (Banska Bystrica region, Slovakia) and drainage water are ones of the greatest environmental burdens in Slovakia. Drainage water from this landfills has pH value higher than 13, and it contains many heavy metals and elevated salt content. In our experiments, relatively numerous bacterial population was detected in the drainage water with frequency of about 80 cfu/ml using cultivation approach. The alkalitolerant heterotrophic isolates were identified by combination of MALDI-TOF and 16S rDNA analysis. Drainage water population was dominated by Actinobacteria (Microbacterium spp. and Micrococcus spp.) followed by low G + C-content gram-positive bacteria (Bacillus spp.). Two isolates belonged to gram-negative bacteria only, identified as Brevundimonas spp. Phylogenetic and biochemical analyses indicate that nearly half of the bacteria isolated are probably representatives of a new species. Brown mud disposal site is proposed as a source of new bacterial taxa possibly used in bioremediation processes. PMID:26077319

  10. Microbial electrolysis desalination and chemical-production cell for CO2 sequestration

    KAUST Repository

    Zhu, Xiuping

    2014-05-01

    Mineral carbonation can be used for CO2 sequestration, but the reaction rate is slow. In order to accelerate mineral carbonation, acid generated in a microbial electrolysis desalination and chemical-production cell (MEDCC) was examined to dissolve natural minerals rich in magnesium/calcium silicates (serpentine), and the alkali generated by the same process was used to absorb CO2 and precipitate magnesium/calcium carbonates. The concentrations of Mg2+ and Ca2+ dissolved from serpentine increased 20 and 145 times by using the acid solution. Under optimal conditions, 24mg of CO2 was absorbed into the alkaline solution and 13mg of CO2 was precipitated as magnesium/calcium carbonates over a fed-batch cycle (24h). Additionally, the MEDCC removed 94% of the COD (initially 822mg/L) and achieved 22% desalination (initially 35g/L NaCl). These results demonstrate the viability of this process for effective CO2 sequestration using renewable organic matter and natural minerals. © 2014 Elsevier Ltd.

  11. Formation of Sulfonyl Aromatic Alcohols by Electrolysis of a Bisazo Reactive Dye

    Directory of Open Access Journals (Sweden)

    María P. Elizalde-González

    2012-12-01

    Full Text Available Five sulfonyl aromatic alcohols, namely 4-((2-hydroxyethylsulfonylphenol, 4-((2-(2-((4-hydroxyphenylsulfonylethoxyvinylsulfonylphenol, 4-(ethylsulfonylphenol, 4-(vinylsulfonylphenol and 5-((4-aminophenylsulfonyl-2-penten-1-ol were identified by LC-ESI-Qq-TOF-MS as products formed by electrolysis of the bisazo reactive dye Reactive Black 5 (RB5. Since electrolyses were performed in an undivided cell equipped with Ni electrodes in alkaline medium, amines like 4-(2-methoxyethylsulfonylbenzene-amine (MEBA with m/z 216 were also suspected to be formed due to the plausible chemical reaction in the bulk or the cathodic reduction of RB5 and its oxidation by-products. Aiming to check this hypothesis, a method was used for the preparation of MEBA with 98% purity, via chemical reduction also of the dye RB5. The logP of the synthesized sulfonyl aromatic compounds was calculated and their logkw values were determined chromatographically. These data were discussed in regard to the relationship between hydrophobicity/lipophilicity and toxicity.

  12. Effect of electrolysis condition of zinc powder production on zinc-silver oxide battery operation

    International Nuclear Information System (INIS)

    A research conducted to produce zinc powder through electrolysis of alkaline solutions by using various concentrations of KOH and zincate in the bath. Different current densities were applied for each concentration and then, morphological changes of Zn powder batches were examined by scanning electron microscopy. Afterward, an anode electrode was produced from each pack of powder. Thirty-six Zn-AgO battery cells were prepared totally. Discharge parameters of the cells were examined and time-voltage curves were analyzed. Discharge times were investigated for various conditions of Zn deposition and the proper terms were suggested. It has been seen that increase of KOH concentration and decrease of zincate ion in the bath solution will change the zinc morphology and increase the resultant battery discharge time. The longest time of discharge, before reduction of cell voltage to 1.25 V, was 7.91 min. This result was obtained for Zn powder produced in zincate concentration of 0.5 M, KOH concentration of 11 M and current density of 2500 A/m2.

  13. Electrochemical Behavior of Ni-Mo Electrocatalyst for Water Electrolysis

    OpenAIRE

    Gerardo Cabau00F1as-Moreno; Eduardo Ordou00F1ez-Regil; Suilma Marisela Fernu00E1ndez-Valverde; Omar Solorza-Feria

    2010-01-01

    Electrocatalizadores base níquel-molibdeno fueron sintetizados en medio orgánico para la reacción de evolución de hidrógeno (HER) y reacción de evolución de oxígeno (OER) en medio alcalino. La estructura, morfología y composición química de los catalizadores fueron evaluados por XRD, SEM y AAS. Los resultados obtenidos mostraron polvos de materiales nanocristalinos con composición química de Ni0.006Mo, Ni0.1Mo y NiMo. El mejor desempeño para la HER fue en electrodos de Ni0.1Mo, y para la OER ...

  14. A Simple Method for Isolation of Caffeine from Black Tea Leaves: Use of a Dichloromethane-Alkaline Water Mixture as an Extractant

    Science.gov (United States)

    Onami, Tetsuo; Kanazawa, Hitoshi

    1996-06-01

    A simple procedure for the isolation of caffeine from tea leaves has been established without using hot or boiling water. A mixture of tea leaves, dichloromethane, and 0.2 M NaOH was shaken for 7 min, and the organic layer was separated. After evaporation of the organic solvent, residual crystals were purified by recrystallization to give 20-30 mg (student yield) of pure caffeine from one tea bag (2 g).

  15. Influence of lake water pH and alkalinity on the distribution of coreand intact polar branched glycerol dialkyl glycerol tetraethers (GDGTs) in lakes

    OpenAIRE

    Schoon, P. L.; de Kluijver, A.; Middelburg, J.J.; J. A. Downing; Sinninghe Damsté, J. S.; Schouten, S.

    2013-01-01

    Branched glycerol dialkyl glycerol tetraethers (GDGTs) are bacterial membrane lipids, ubiquitously present in soils and peat bogs, as well as in rivers, lakes and lake sediments. Their distribution in soil is controlled mainly by pH and mean annual air temperature, but the controls on their distribution in lake sediments are less well understood. Several studies have found a relationship between the distribution of branched GDGTs in lake sediments and average lake water pH, suggesting an aqua...

  16. Modulators of intestinal alkaline phosphatase.

    Science.gov (United States)

    Bobkova, Ekaterina V; Kiffer-Moreira, Tina; Sergienko, Eduard A

    2013-01-01

    Small molecule modulators of phosphatases can lead to clinically useful drugs and serve as invaluable tools to study functional roles of various phosphatases in vivo. Here, we describe lead discovery strategies for identification of inhibitors and activators of intestinal alkaline phosphatases. To identify isozyme-selective inhibitors and activators of the human and mouse intestinal alkaline phosphatases, ultrahigh throughput chemiluminescent assays, utilizing CDP-Star as a substrate, were developed for murine intestinal alkaline phosphatase (mIAP), human intestinal alkaline phosphatase (hIAP), human placental alkaline phosphatase (PLAP), and human tissue-nonspecific alkaline phosphatase (TNAP) isozymes. Using these 1,536-well assays, concurrent HTS screens of the MLSMR library of 323,000 compounds were conducted for human and mouse IAP isozymes monitoring both inhibition and activation. This parallel screening approach led to identification of a novel inhibitory scaffold selective for murine intestinal alkaline phosphatase. SAR efforts based on parallel testing of analogs against different AP isozymes generated a potent inhibitor of the murine IAP with IC50 of 540 nM, at least 65-fold selectivity against human TNAP, and >185 selectivity against human PLAP. PMID:23860652

  17. Alkaline battery, separator therefore

    Science.gov (United States)

    Schmidt, George F. (Inventor)

    1980-01-01

    An improved battery separator for alkaline battery cells has low resistance to electrolyte ion transfer and high resistance to electrode ion transfer. The separator is formed by applying an improved coating to an electrolyte absorber. The absorber, preferably, is a flexible, fibrous, and porous substrate that is resistant to strong alkali and oxidation. The coating composition includes an admixture of a polymeric binder, a hydrolyzable polymeric ester and inert fillers. The coating composition is substantially free of reactive fillers and plasticizers commonly employed as porosity promoting agents in separator coatings. When the separator is immersed in electrolyte, the polymeric ester of the film coating reacts with the electrolyte forming a salt and an alcohol. The alcohol goes into solution with the electrolyte while the salt imbibes electrolyte into the coating composition. When the salt is formed, it expands the polymeric chains of the binder to provide a film coating substantially permeable to electrolyte ion transfer but relatively impermeable to electrode ion transfer during use.

  18. Inhibitory effect of tungstate, molybdate and nitrite ions on the carbon steel pitting corrosion in alkaline formation water containing Cl- ion

    International Nuclear Information System (INIS)

    The pitting corrosion of carbon steel in carbonate-formation water solution in the presence of chloride ions and the effect of addition WO42-, MoO42- and NO2- anions on the pitting corrosion were studied using cyclic voltammetry and potentiostatic current-time measurements and complemented by scan electron microscope (SEM), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) investigations. Cyclic voltammograms of carbon steel in the presence of chloride ions in carbonate-formation water solution show one anodic peak, corresponding to the formation green rust carbonate and the two cathodic peaks. As the addition of Cl- ions concentration increases, the anodic peak current density increases and pitting potential Epit shifts to more negative potential. It is shown that the rate of pit initiation (ti-1) decreases and the pitting potential Epit moves to more positive direction upon the addition of inorganic anions. It was found that pitting inhibition of carbon steel increases in the sequence: (WO4)2- > (MoO4)2- > (NO2)-

  19. Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

    Science.gov (United States)

    Saksono, Nelson; Febiyanti, Irine Ayu; Utami, Nissa; Ibrahim

    2015-12-01

    Plasma electrolysis is an effective technology for producing hydroxyl radical (•OH). This method can be used for waste degradation process. This study was conducted to obtain the influence of applied voltage, electrolyte concentration, and anode depth in the plasma electrolysis system for producing hydroxyl radical. The materials of anode and cathode, respectively, were made from tungsten and stainless steel. KOH solution was used as the solution. Determination of hydroxyl radical production was done by measuring H2O2 amount formed in plasma system using an iodometric titration method, while the electrical energy consumed was obtained by measuring the electrical current throughout the process. The highest hydroxyl radical production was 3.51 mmol reached with 237 kJ energy consumption in the power supply voltage 600 V, 0.02 M KOH, and 0.5 cm depth of anode.

  20. Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

    International Nuclear Information System (INIS)

    Plasma electrolysis is an effective technology for producing hydroxyl radical (•OH). This method can be used for waste degradation process. This study was conducted to obtain the influence of applied voltage, electrolyte concentration, and anode depth in the plasma electrolysis system for producing hydroxyl radical. The materials of anode and cathode, respectively, were made from tungsten and stainless steel. KOH solution was used as the solution. Determination of hydroxyl radical production was done by measuring H2O2 amount formed in plasma system using an iodometric titration method, while the electrical energy consumed was obtained by measuring the electrical current throughout the process. The highest hydroxyl radical production was 3.51 mmol reached with 237 kJ energy consumption in the power supply voltage 600 V, 0.02 M KOH, and 0.5 cm depth of anode

  1. Natural gas anodes for aluminium electrolysis in molten fluorides.

    Science.gov (United States)

    Haarberg, Geir Martin; Khalaghi, Babak; Mokkelbost, Tommy

    2016-08-15

    Industrial primary production of aluminium has been developed and improved over more than 100 years. The molten salt electrolysis process is still suffering from low energy efficiency and considerable emissions of greenhouse gases (CO2 and PFC). A new concept has been suggested where methane is supplied through the anode so that the CO2 emissions may be reduced significantly, the PFC emissions may be eliminated and the energy consumption may decrease significantly. Porous carbon anodes made from different graphite grades were studied in controlled laboratory experiments. The anode potential, the anode carbon consumption and the level of HF gas above the electrolyte were measured during electrolysis. In some cases it was found that the methane oxidation was effectively participating in the anode process. PMID:27210046

  2. HYFIRE: a tokamak-high-temperature electrolysis system

    International Nuclear Information System (INIS)

    Brookhaven National Laboratory (BNL) is carrying out a comprehensive conceptual design study called HYFIRE of a commercial fusion Tokamak reactor, high-temperature electrolysis system. The study is placing particular emphasis on the adaptability of the STARFIRE power reactor to a synfuel application. The HYFIRE blanket must perform three functions: (a) provide high-temperature (approx. 14000C) process steam at moderate pressures (in the range of 10 to 30 atm) to the high-temperature electrolysis (HTE) units; (b) provide high-temperature (approx. 7000 to 8000C) heat to a thermal power cycle for generation of electricity to the HTE units; and (c) breed enough tritium to sustain the D-T fuel cycle. In addition to thermal energy for the decomposition of steam into its constituents, H2 and O2, electrical input is required. Fourteen hundred degree steam coupled with 40% power cycle efficiency results in a process efficiency (conversion of fusion energy to hydrogen chemical energy) of 50%

  3. HYFIRE: a tokamak-high-temperature electrolysis system

    International Nuclear Information System (INIS)

    Brookhaven National Laboratory (BNL) is carrying out a comprehensive conceptual design study called HYFIRE of a commercial fusion Tokamak reactor, high-temperature electrolysis system. The study is placing particular emphasis on the adaptability of the STARFIRE power reactor to a synfuel application. The HYFIRE blanket must perform three functions: (a) provide high-temperature (approx. 14000C) process steam at moderate pressures (in the range of 10 to 30 atm) to the high-temperature electrolysis (HTE) units; (b) provide high-temperature (approx. 7000 to 8000C) heat to a thermal power cycle for generation of electricity to the HTE units; and (c) breed enough tritium to sustain the D-T fuel cycle. In addition to thermal energy for the decomposition of steam into its constituents, H2 and O2, electrical input is required. Fourteen hundred degree steam coupled with 40% power efficiency results in a process efficiency (conversion of fusion energy to hydrogen chemical energy) of 50%

  4. Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

    Energy Technology Data Exchange (ETDEWEB)

    Saksono, Nelson; Febiyanti, Irine Ayu, E-mail: irine.ayu41@ui.ac.id; Utami, Nissa; Ibrahim [Department of Chemical Engineering, Universitas Indonesia, Depok 16424, Indonesia Phone: +62217863516, Fax: +62217863515 (Indonesia)

    2015-12-29

    Plasma electrolysis is an effective technology for producing hydroxyl radical (•OH). This method can be used for waste degradation process. This study was conducted to obtain the influence of applied voltage, electrolyte concentration, and anode depth in the plasma electrolysis system for producing hydroxyl radical. The materials of anode and cathode, respectively, were made from tungsten and stainless steel. KOH solution was used as the solution. Determination of hydroxyl radical production was done by measuring H{sub 2}O{sub 2} amount formed in plasma system using an iodometric titration method, while the electrical energy consumed was obtained by measuring the electrical current throughout the process. The highest hydroxyl radical production was 3.51 mmol reached with 237 kJ energy consumption in the power supply voltage 600 V, 0.02 M KOH, and 0.5 cm depth of anode.

  5. Neutron emission during Pd-D2O electrolysis

    International Nuclear Information System (INIS)

    A clear correlation has been found between neutron counting and the pulsation of an electrolysis current obtained with different Pd cathodes (rolled and wire) in D2O. Different spectra as a function of time synchronized with the electrolysis current of Pd-D2O and Pd-H2O are presented, all in identical conditions. Measurements in Pd-D2O lack the (statistically significant) synchronic increments in counting which are observed when the electrolite used is D2O. On the hypothesis that the observed neutrons are originated in Deuteron fusion with a branching ratio 0.5, the obtained countings correspond to a fusion rate of approximately 0.5 fusions/second. (Author)

  6. Direct Lit Electrolysis In A Metallic Lithium Fusion Blanket

    Energy Technology Data Exchange (ETDEWEB)

    Colon-Mercado, H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Babineau, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Elvington, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Garcia-Diaz, B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Teprovich, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Vaquer, A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-13

    A process that simplifies the extraction of tritium from molten lithium based breeding blankets was developed.  The process is based on the direct electrolysis of lithium tritide using a ceramic Li ion conductor that replaces the molten salt extraction step. Extraction of tritium in the form of lithium tritide in the blankets/targets of fission/fusion reactors is critical in order to maintained low concentrations.  This is needed to decrease the potential tritium permeation to the surroundings and large releases from unforeseen accident scenarios. Because of the high affinity of tritium for the blanket, extraction is complicated at the required low levels. This work identified, developed and tested the use of ceramic lithium ion conductors capable of recovering the hydrogen and deuterium thru an electrolysis step at high temperatures. 

  7. Electrolysis of plutonium in neutral and basic solutions

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-01

    Experiments were conducted on electrolysis of Pu in waste streams. Removal of Pu by this process is maximum at pH 11. Runs on an actual waste stream showed that: Pu can be electrolyzed from neutral or basic solutions down to 10/sup -10/ g/l. Am can also be removed. The removal efficiency is pH dependent. The deposits can be removed by acid leaching. (DLC)

  8. Characteristics of particulate emissions from aluminium electrolysis cells

    OpenAIRE

    Gaertner, Heiko

    2013-01-01

    Modern sampling and analysis techniques were applied to study the morphology and composition of pot exhaust particles from aluminium smelters. In this study the total spectrum of pot exhaust particles from prebake electrolysis cells was sampled on filters and in a standard cyclone. Application of a cascade impactor allowed for fractionation of raw gas dust into 12 fractions with particle diameters in the range from approximately 7 nm to 10 μm. The performed experiments demonstrated that the p...

  9. Electrochemical disinfection of toilet wastewater using wastewater electrolysis cell

    OpenAIRE

    Huang, Xiao; Qu, Yan; Cid, Clément A.; Finke, Cody; Hoffmann, Michael R; Lim, Keahying; Jiang, Sunny C.

    2016-01-01

    The paucity of proper sanitation facilities has contributed to the spread of waterborne diseases in many developing countries. The primary goal of this study was to demonstrate the feasibility of using a wastewater electrolysis cell (WEC) for toilet wastewater disinfection. The treated wastewater was designed to reuse for toilet flushing and agricultural irrigation. Laboratory-scale electrochemical (EC) disinfection experiments were performed to investigate the disinfection efficiency of the ...

  10. Solid Oxide Electrolysis Cells: Degradation at High Current Densities

    DEFF Research Database (Denmark)

    Knibbe, Ruth; Traulsen, Marie Lund; Hauch, Anne; Ebbesen, Sune; Mogensen, Mogens Bjerg

    2010-01-01

    The degradation of Ni/yttria-stabilized zirconia (YSZ)-based solid oxide electrolysis cells operated at high current densities was studied. The degradation was examined at 850°C, at current densities of −1.0, −1.5, and −2.0 A/cm2, with a 50:50 (H2O:H2) gas supplied to the Ni/YSZ hydrogen electrode...

  11. Application of mercury cathode electrolysis to fission-product separation

    International Nuclear Information System (INIS)

    A method involving controlled potential mercury cathode electrolysis has been developed to separate fission products. It allows the radiochemical determination of Ag, Cd, Pd, Rh, Ru, Sn, Te, Sb and Mo from solutions of fission products highly concentrated in mineral salts. The general procedure consists in three main steps: electrolytic amalgam generation, destruction of amalgams and ultimate purification of elements by other means. Electrolytic operations last about five hours. Chemical yields lie between 10 per cent and 70 per cent. (authors)

  12. Mechanism of the transfer of alkali- and alkaline-earth-metal ions across the nitrobenzene-water interface facilitated by hexa- and octaethylene glycol dodecyl ethers

    International Nuclear Information System (INIS)

    Transfer of Li+, Na+ , K+, Rb+, Ca2+, Sr2+, and Ba2+ ions facilitated by hexa- and octaethylene glycol monododecyl ethers (C12E6 and C12E8) has been studied at the nitrobenzene (NB)- water (W) interface using cyclic voltammetry. When the concentration of C12En (n = 6 or 8) in NB is higher than 1 mM, cyclic voltammograms for all these ions show reversible transfer of ions facilitated by C12En. The current is mainly carried by 1:1 (metal:ligand) complex and is limited by the diffusion of C12En in NB. When the concentration of C12En in NB is lowered to the submillimolar range, the contribution of the adsorption of C12En to the current becomes significant. In the transfer of hydrophilic ions, e.g., Li + and Ca2+, the contribution of the complex with 1:2 (metal:ligand) stoichiometry to the measured current becomes nonnegligible. This 1:2 complex formation becomes pronounced with increasing ligand concentration

  13. A hybrid wind-PV system performance investigation for the purpose of maximum hydrogen production and storage using advanced alkaline electrolyzer

    International Nuclear Information System (INIS)

    Highlights: • A new index for optimal sizing of system is proposed. • Electromechanical model of all components is designed and simulated using MATLAB. • Detailed and accurate model of advanced alkaline electrolyzer is simulated. • Three different conditions of using WT and PV array for this system are discussed. • Actual data for weekly irradiation, wind speed, and temperature of Sahand are used. - Abstract: In this study, design and modelling of hybrid wind–photovoltaic system is done for the purpose of hydrogen production through water electrolysis. Actual data for weekly solar irradiation, wind speed, and ambient temperature of Sahand, Iran, are used for performance simulation and analysis of the system examined. The detailed model of components is used. The 10 kW alkaline electrolyzer model, which produces hydrogen, is based on combination of empirical electrochemical relationships, thermodynamics, and heat transfer theory. The operation of this system is optimized using imperial competitive colony algorithm. The objective of optimization is to maximize hydrogen production, considering minimum production of average excess power. This system is analysed in three different conditions of using just wind turbine (WT), photovoltaic (PV) array, and combination of them as power source, producing hydrogen of 8297, 4592, and 10,462 mol, respectively. As for this result and with analysing other results of simulation, it is clarified that the hybrid system is more useful for this study. In hybrid form the ratio of average produced power to nominal power for PV array is 0.247 and for WT is 0.493 which demonstrates that WT is more effective in production

  14. Basic study of cold fusion. 1. The development of excess heat measurement system in electrolysis

    International Nuclear Information System (INIS)

    We have an opportunity ripe to investigate the cold fusion phenomena. In order to declare the subjects to be examined, the precision calorimetry system was developed to try to reproduce the phenomena. The electrolysis of heavy water with palladium cathode was conducted based on the thought that it is important to confirm the cold fusion phenomena. For precision excess power measurement, the closed cell with recombiner and flow-calorimetry were adopted. The obtained accuracy for the excess power measurement of the system was ±0.2 W at up to 9 W of applied power. This is enough for the excess power reported as the cold fusion phenomena. For farther investigation, measurement of loading ratio of deuterium in the palladium cathode, maintenance of high deuterium loading and analysis of the palladium cathode are to be conducted. (author)

  15. Microbial electrolysis cells turning to be versatile technology: recent advances and future challenges

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Angelidaki, Irini

    2014-01-01

    energetically unfavorable biological/chemical reactions. This unique advantage of MECs has led to several alternative applications such as chemicals synthesis, recalcitrant pollutants removal, resources recovery, bioelectrochemical research platform and biosensors, which have greatly broaden the application...... scopes of MECs. MECs are becoming a versatile platform technology and offer a new solution for emerging environmental issues related to waste streams treatment and energy and resource recovery. Different from previous reviews that mainly focus on hydrogen production, this paper provides an up...... and achieve high-yield hydrogen production from wide range of organic matters at relatively mild conditions. This approach greatly reduces the electric energy cost for hydrogen production in contrast to direct water electrolysis. In addition to hydrogen production, MECs may also support several...

  16. Thermochemical Production of Hydrogen from Water.

    Science.gov (United States)

    Bamberger, C. E.; And Others

    1978-01-01

    Discusses the possible advantages of decomposing water by means of thermochemical cycles. Explains that, if energy consumption can be minimized, this method is capable of producing hydrogen more efficiently than electrolysis. (GA)

  17. The alkaline and alkaline-carbonatite magmatism from Southern Brazil

    Science.gov (United States)

    Ruberti, E.; Gomes, C. D. B.; Comin-Chiaramonti, P.

    2015-12-01

    Early to Late Cretaceous lasting to Paleocene alkaline magmatism from southern Brazil is found associated with major extensional structural features in and around the Paraná Basin and grouped into various provinces on the basis of several data. Magmatism is variable in size, mode of occurrence and composition. The alkaline rocks are dominantly potassic, a few occurrences showing sodic affinity. The more abundant silicate rocks are evolved undersaturated to saturated in silica syenites, displaying large variation in igneous forms. Less evolved types are restricted to subvolcanic environments and outcrops of effusive suites occur rarely. Cumulatic mafic and ultramafic rock types are very common, particularly in the alkali-carbonatitic complexes. Carbonatite bodies are represented by Ca-carbonatites and Mg-carbonatites and more scarcely by Fe-carbonatites. Available radiometric ages for the alkaline rocks fit on three main chronological groups: around 130 Ma, subcoveal with the Early Cretaceous flood tholeiites of the Paraná Basin, 100-110 Ma and 80-90 Ma (Late Cretaceous). The alkaline magmatism also extends into Paleocene times, as indicated by ages from some volcanic lavas. Geochemically, alkaline potassic and sodic rock types are distinguished by their negative and positive Nb-Ta anomalies, respectively. Negative spikes in Nb-Ta are also a feature common to the associated tholeiitic rocks. Sr-Nd-Pb systematics confirm the contribution of both HIMU and EMI mantle components in the formation of the alkaline rocks. Notably, Early and Late Cretaceous carbonatites have the same isotopic Sr-Nd initial ratios of the associated alkaline rocks. C-O isotopic Sr-Nd isotopic ratios indicate typical mantle signature for some carbonatites and the influence of post-magmatic processes in others. Immiscibility of liquids of phonolitic composition, derived from mafic alkaline parental magmas, has been responsible for the origin of the carbonatites. Close association of alkaline

  18. Method and apparatus for enrichment or upgrading heavy water

    International Nuclear Information System (INIS)

    A method and apparatus for upgrading and final enrichment of heavy water are described, comprising means for contacting partially enriched heavy water feed in a catalyst column with hydrogen gas (essentially D2) originating in an electrolysis cell so as to enrich the feed water with deuterium extracted from the electrolytic hydrogen gas and means for passing the deuterium enriched water to the electrolysis cell. (author)

  19. Evaluation of hydraulic conductivities of bentonite and rock under hyper alkaline and nitrate conditions. 2

    International Nuclear Information System (INIS)

    Circumstance of TRU waste repository shows alkaline condition due to leaching of cementitious materials. The waste containing significant soluble nitrate may changes ground water chemistry to high ion strength. Several experimental studies have been carried out in this study in order to assess quantitatively water conductivity of bentonite which is altered by hyper alkaline and nitrate. Modeling for previous results is carried out and several requirements to be defined are proposed. The conclusion of this study is summarized as below. Secondary minerals of bentonite alteration due to hyper alkaline with nitrate: 1) CSH and CAH were observed corresponding to solving montmorillonite in AWN solution. 2) Na2O Al2O3 1.68SiO2 generated from 90 days in batch experiment and it was observed in 360 days. Assessment of swelling and water conductivity changing by hyper alkaline with nitrate: 1) Little changing of water conductivity of bentonite was observed by saturated Ca(OH)2 solution and hyper alkaline solution. The conductivity significantly increased by penetrating sodium nitrate solution. 2) Water conductivity of ion exchanged bentonite by hyper alkaline solution significantly increased. It increased more by penetrating AWN solution. Modeling of tuff alteration by hyper alkaline solution: 1) Flow through test is proposed since soluble velocity to hyper alkaline solution should be defined. (author)

  20. Corrosion of copper in alkaline chloride environments

    International Nuclear Information System (INIS)

    The available literature information on the corrosion and electrochemical behaviour of copper in alkaline environments has been reviewed. The purpose of the review was to assess the impact of an alkaline plume from cementitious material on the corrosion behaviour of a copper canister in an SKB-3 type repository. The effect of the evolution of the environmental conditions within the repository have been considered, including the effects of temperature, redox conditions, pore-water salinity and pH. If the pore-water pH increases prior to the establishment of anoxic conditions, the canister surface will passivate as the pore-water pH exceeds a value of ∼ pH 9. Passivation will result from the formation of a duplex Cu2O/Cu(OH)2 film. The corrosion potential will be determined by the equilibrium potential for the Cu2O/Cu(OH)2 couple under oxic conditions, or by the Cu/Cu2O redox couple under anoxic conditions (in the absence of sulphide). Pitting corrosion is only likely to occur early in the evolution of the repository environment, whilst the canister is still relatively cool (2 available to support localised corrosion, and prior to the increase in pore-water pH and salinity. The subsequent increase in canister surface temperature, pore-water pH and salinity, and decrease in O2 will make pit initiation less likely, although the canister will remain passive provided the pore-water pH is maintained above pH 9. The higher the pore-water pH, the more strongly the canister is passivated and the less likely the surface is to undergo localised attack. If the pore-water salinity increases prior to the increase in pH, there could be a period of active canister corrosion before passivation occurs.Under these circumstances, the corrosion potential will be a true mixed potential, determine by the relative kinetics of Cu dissolution as CuCl2 - and of the reduction of O2. The development of anoxic conditions and an increase in pore-water sulphide concentration will result in

  1. Nanosized IrOx–Ir Catalyst with Relevant Activity for Anodes of Proton Exchange Membrane Electrolysis Produced by a Cost-Effective Procedure

    OpenAIRE

    Lettenmeier, Philipp; Wang, Li; Golla-Schindler, Ute; Gazdzicki, Pawel; Cañas, Natalia A.; Handl, Michael; Hiesgen, Renate; Hosseiny, S.S.; Gago, Aldo; Friedrich, K. Andreas

    2015-01-01

    We have developed a highly active nanostructured iridium catalyst for anodes of proton exchange membrane (PEM) electrolysis. Clusters of nanosized crystallites are obtained by reducing surfactant-stabilized IrCl3 in water-free conditions. The catalyst shows a five-fold higher activity towards oxygen evolution reaction (OER) than commercial Ir-black. The improved kinetics of the catalyst are reflected in the high performance of the PEM electrolyzer (1 mgIr cm−2), showing an unparalleled low ov...

  2. Boosting water oxidation layer-by-layer.

    Science.gov (United States)

    Hidalgo-Acosta, Jonnathan C; Scanlon, Micheál D; Méndez, Manuel A; Amstutz, Véronique; Vrubel, Heron; Opallo, Marcin; Girault, Hubert H

    2016-04-01

    Electrocatalysis of water oxidation was achieved using fluorinated tin oxide (FTO) electrodes modified with layer-by-layer deposited films consisting of bilayers of negatively charged citrate-stabilized IrO2 NPs and positively charged poly(diallyldimethylammonium chloride) (PDDA) polymer. The IrO2 NP surface coverage can be fine-tuned by controlling the number of bilayers. The IrO2 NP films were amorphous, with the NPs therein being well-dispersed and retaining their as-synthesized shape and sizes. UV/vis spectroscopic and spectro-electrochemical studies confirmed that the total surface coverage and electrochemically addressable surface coverage of IrO2 NPs increased linearly with the number of bilayers up to 10 bilayers. The voltammetry of the modified electrode was that of hydrous iridium oxide films (HIROFs) with an observed super-Nernstian pH response of the Ir(iii)/Ir(iv) and Ir(iv)-Ir(iv)/Ir(iv)-Ir(v) redox transitions and Nernstian shift of the oxygen evolution onset potential. The overpotential of the oxygen evolution reaction (OER) was essentially pH independent, varying only from 0.22 V to 0.28 V (at a current density of 0.1 mA cm(-2)), moving from acidic to alkaline conditions. Bulk electrolysis experiments revealed that the IrO2/PDDA films were stable and adherent under acidic and neutral conditions but degraded in alkaline solutions. Oxygen was evolved with Faradaic efficiencies approaching 100% under acidic (pH 1) and neutral (pH 7) conditions, and 88% in alkaline solutions (pH 13). This layer-by-layer approach forms the basis of future large-scale OER electrode development using ink-jet printing technology. PMID:26977761

  3. Iron migration from the anode surface in alumina electrolysis

    Science.gov (United States)

    Zhuravleva, Elena N.; Drozdova, Tatiana N.; Ponomareva, Svetlana V.; Kirik, Sergei D.

    2013-01-01

    Corrosion destruction of two-component iron-based alloys used as an anode in high-temperature alumina electrolysis in the melt of NaF/KF/AlF3 electrolyte has been considered. Ni, Si, Cu, Cr, Mn, Al, Ti in the amount of up to 10% have been tested as the dopants to an anode alloys. The composition of the corrosion products has been studied using X-ray diffraction, scanning electron microscopy and electron microprobe analysis. It has been established that the anode corrosion is induced by a surface electrochemical polarization and iron atom oxidation. Iron ions come into an exchange interaction with the fluoride components of the melted electrolyte, producing FeF2. The last interacts with oxyfluoride species transforming into the oxide forms: FeAl2O4, Fe3O4, Fe2O3. Due to the low solubility, the iron oxides are accumulated in the near-electrode sheath. The only small part of iron from anode migrates to cathode that makes an production of high purity aluminum of a real task. The alloy dopants are also subjected to corrosion in accordance with electromotive series resulting corrosion tunnels on the anode surface. The oxides are final compounds which collect in the same area. The corrosion products form an anode shell which is electronic conductor at electrolysis temperature. The electrolysis of alumina occurs beyond the corrosion shell. The rate limiting step in the corrosion is the electrolyte penetration through corrosion shell to the anode surface. The participation of the released oxygen in the corrosion has not been observed.

  4. A metallic seal for high-temperature electrolysis stacks

    International Nuclear Information System (INIS)

    Gas tightness over a long period of time is a real challenge in high-temperature electrolysis. The seals must indeed be able to run at high temperature between metals and brittle ceramic materials, which is a major issue to be solved. The common sealing solution relies on glass-made seals, despite their low mechanical strength at high temperature. Metallic seals have seldom been used in this field, because their stiffness and their hardness require a much higher load to achieve the appropriate tightness. In the French project ANR Pan-H/SEMIEHT, two different sealing solutions were investigated in two different locations of the GENHEPIS-G1 stack. Experiments were carried out with a glass-made seal between the cell and its ceramic support, and with metallic seals between the interconnect and the cell support, in order to seal the gas input and output as well as the cathodic chamber. An initial Garlock seal design has been optimised in order to decrease the seating load. Seals were also manufactured by Garlock. The C-shaped seals are made of two components: an Inconel-X750-made elastic inner part, and a specially profiled Fecralloy-made 'soft' outer lining. The use of Fecralloy enables the generation of an alumina thin layer, which both protects the seal and eases disassembly. In this study, these seals were tested on specific equipments and on actual stacks. It is shown that they are tight enough to achieve the electrolysis tests at 800 deg. C. Therefore a significant breakthrough in high-temperature electrolysis sealing has been achieved. It sheds new light on the actual potential of metallic seals and constitutes a basis for ongoing studies, such as another French project, namely ANR/Pan-H/EMAIL. (authors)

  5. High School Students' Proficiency and Confidence Levels in Displaying Their Understanding of Basic Electrolysis Concepts

    Science.gov (United States)

    Sia, Ding Teng; Treagust, David F.; Chandrasegaran, A. L.

    2012-01-01

    This study was conducted with 330 Form 4 (grade 10) students (aged 15-16 years) who were involved in a course of instruction on electrolysis concepts. The main purposes of this study were (1) to assess high school chemistry students' understanding of 19 major principles of electrolysis using a recently developed 2-tier multiple-choice diagnostic…

  6. Production of Synthetic Fuels by Co-Electrolysis of Steam and Carbon Dioxide

    DEFF Research Database (Denmark)

    Ebbesen, Sune; Graves, Christopher R.; Mogensen, Mogens Bjerg

    2009-01-01

    Co-electrolysis of H2O and CO2 was studied in solid oxide cells (SOCs) supported by nickel-/yittria-stabilized zirconia (Ni/YSZ) electrode. Polarization characterization indicates that electrochemical reduction of both CO2 and H2O occurs during co-electrolysis. In parallel with the electrochemical...

  7. Solid Oxide Electrolysis Cells: Microstructure and Degradation of the Ni/Yttria-Stabilized Zirconia Electrode

    DEFF Research Database (Denmark)

    Hauch, Anne; Ebbesen, Sune; Jensen, Søren Højgaard;

    2008-01-01

    Solid oxide fuel cells produced at Risø DTU have been tested as solid oxide electrolysis cells for steam electrolysis by applying an external voltage. Varying the sealing on the hydrogen electrode side of the setup verifies that the previously reported passivation over the first few hundred hours...

  8. Iron migration from the anode surface in alumina electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Zhuravleva, Elena N.; Drozdova, Tatiana N.; Ponomareva, Svetlana V. [Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); Kirik, Sergei D., E-mail: kiriksd@yandex.ru [Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); Institute of Chemistry and Chemical Technology SB RAS, Krasnoyarsk, 660036 (Russian Federation)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Corrosion destruction of two-component iron-based alloys in high-temperature aluminum electrolysis in the cryolite alumina melt has been studied. Black-Right-Pointing-Pointer It was found that at the first stage oxidative polarization of iron atoms on the anode surface into Fe{sup 2+} takes place. Black-Right-Pointing-Pointer Fe{sup 2+} interacts with cryolite melt producing FeF{sub 2}. Black-Right-Pointing-Pointer FeF{sub 2} gives oxides FeAl{sub 2}O{sub 4}, Fe{sub 3}O{sub 4}, Fe{sub 2}O{sub 3}. Black-Right-Pointing-Pointer The participation of oxygen in the corrosion has not been observed. - Abstract: Corrosion destruction of two-component iron-based alloys used as an anode in high-temperature alumina electrolysis in the melt of NaF/KF/AlF{sub 3} electrolyte has been considered. Ni, Si, Cu, Cr, Mn, Al, Ti in the amount of up to 10% have been tested as the dopants to an anode alloys. The composition of the corrosion products has been studied using X-ray diffraction, scanning electron microscopy and electron microprobe analysis. It has been established that the anode corrosion is induced by a surface electrochemical polarization and iron atom oxidation. Iron ions come into an exchange interaction with the fluoride components of the melted electrolyte, producing FeF{sub 2}. The last interacts with oxyfluoride species transforming into the oxide forms: FeAl{sub 2}O{sub 4}, Fe{sub 3}O{sub 4}, Fe{sub 2}O{sub 3}. Due to the low solubility, the iron oxides are accumulated in the near-electrode sheath. The only small part of iron from anode migrates to cathode that makes an production of high purity aluminum of a real task. The alloy dopants are also subjected to corrosion in accordance with electromotive series resulting corrosion tunnels on the anode surface. The oxides are final compounds which collect in the same area. The corrosion products form an anode shell which is electronic conductor at electrolysis temperature. The

  9. Experimental study of the electrolysis of silicate melts

    Science.gov (United States)

    Keller, R.; Larimer, K. T.

    1991-01-01

    To produce oxygen from lunar resources, it may be feasible to melt and electrolyze local silicate ores. This possibility was explored experimentally with synthesized melts of appropriate compositions. Platinum electrodes were employed at a melt temperature of 1425 C. When silicon components of the melt were reduced, the platinum cathode degraded rapidly, which prompted the substitution of a graphite cathode substrate. Discrete particles containing iron or titanium were found in the solidified electrolyte after three hours of electrolysis. Electrolyte conductivities did not decrease substantially, but the escape of gas bubbles, in some cases, appeared to be hindered by high viscosity of the melt.

  10. DEGRADATION ISSUES IN SOLID OXIDE CELLS DURING HIGH TEMPERATURE ELECTROLYSIS

    Energy Technology Data Exchange (ETDEWEB)

    J. E. O' Brien; C. M. Stoots; V. I. Sharma; B. Yildiz; A. V. Virkar

    2010-06-01

    Idaho National Laboratory (INL) is performing high-temperature electrolysis research to generate hydrogen using solid oxide electrolysis cells (SOECs). The project goals are to address the technical and degradation issues associated with the SOECs. This paper provides a summary of various ongoing INL and INL sponsored activities aimed at addressing SOEC degradation. These activities include stack testing, post-test examination, degradation modeling, and a list of issues that need to be addressed in future. Major degradation issues relating to solid oxide fuel cells (SOFC) are relatively better understood than those for SOECs. Some of the degradation mechanisms in SOFCs include contact problems between adjacent cell components, microstructural deterioration (coarsening) of the porous electrodes, and blocking of the reaction sites within the electrodes. Contact problems include delamination of an electrode from the electrolyte, growth of a poorly (electronically) conducting oxide layer between the metallic interconnect plates and the electrodes, and lack of contact between the interconnect and the electrode. INL’s test results on high temperature electrolysis (HTE) using solid oxide cells do not provide a clear evidence whether different events lead to similar or drastically different electrochemical degradation mechanisms. Post-test examination of the solid oxide electrolysis cells showed that the hydrogen electrode and interconnect get partially oxidized and become non-conductive. This is most likely caused by the hydrogen stream composition and flow rate during cool down. The oxygen electrode side of the stacks seemed to be responsible for the observed degradation due to large areas of electrode delamination. Based on the oxygen electrode appearance, the degradation of these stacks was largely controlled by the oxygen electrode delamination rate. University of Utah (Virkar) has developed a SOEC model based on concepts in local thermodynamic equilibrium in

  11. Thermal imaging of solid oxide cells operating under electrolysis conditions

    Science.gov (United States)

    Cumming, D. J.; Elder, R. H.

    2015-04-01

    Solid oxide fuel cells remain at the forefront of research into electrochemical energy conversion technology. More recent interest has focused on operating in electrolyser mode to convert steam or carbon dioxide into hydrogen or carbon monoxide, respectively. The mechanism of these reactions is not fully understood, particularly when operated in co-electrolysis mode using both steam and CO2. This contribution reports the use of a thermal camera to directly observe changes in the cell temperature during operation, providing a remote, non-contact and highly sensitive method for monitoring an operational cell.

  12. Production of Oxygen from Lunar Regolith by Molten Oxide Electrolysis

    Science.gov (United States)

    Curreri, Peter A.

    2009-01-01

    This paper describes the use of the molten oxide electrolysis (MOE) process for the extraction of oxygen for life support and propellant, and silicon and metallic elements for use in fabrication on the Moon. The Moon is rich in mineral resources, but it is almost devoid of chemical reducing agents, therefore, molten oxide electrolysis is ideal for extraction, since the electron is the only practical reducing agent. MOE has several advantages over other extraction methods. First, electrolytic processing offers uncommon versatility in its insensitivity to feedstock composition. Secondly, oxide melts boast the twin key attributes of highest solubilizing capacity for regolith and lowest volatility of any candidate electrolytes. The former is critical in ensuring high productivity since cell current is limited by reactant solubility, while the latter simplifies cell design by obviating the need for a gas-tight reactor to contain evaporation losses as would be the case with a gas or liquid phase fluoride reagent operating at such high temperatures. Alternatively, MOE requires no import of consumable reagents (e.g. fluorine and carbon) as other processes do, and does not rely on interfacing multiple processes to obtain refined products. Electrolytic processing has the advantage of selectivity of reaction in the presence of a multi-component feed. Products from lunar regolith can be extracted in sequence according to the stabilities of their oxides as expressed by the values of the free energy of oxide formation (e.g. chromium, manganese, Fe, Si, Ti, Al, magnesium, and calcium). Previous work has demonstrated the viability of producing Fe and oxygen from oxide mixtures similar in composition to lunar regolith by molten oxide electrolysis (electrowinning), also called magma electrolysis having shown electrolytic extraction of Si from regolith simulant. This paper describes recent advances in demonstrating the MOE process by a joint project with participation by NASA KSC and

  13. Iron migration from the anode surface in alumina electrolysis

    International Nuclear Information System (INIS)

    Highlights: ► Corrosion destruction of two-component iron-based alloys in high-temperature aluminum electrolysis in the cryolite alumina melt has been studied. ► It was found that at the first stage oxidative polarization of iron atoms on the anode surface into Fe2+ takes place. ► Fe2+ interacts with cryolite melt producing FeF2. ► FeF2 gives oxides FeAl2O4, Fe3O4, Fe2O3. ► The participation of oxygen in the corrosion has not been observed. - Abstract: Corrosion destruction of two-component iron-based alloys used as an anode in high-temperature alumina electrolysis in the melt of NaF/KF/AlF3 electrolyte has been considered. Ni, Si, Cu, Cr, Mn, Al, Ti in the amount of up to 10% have been tested as the dopants to an anode alloys. The composition of the corrosion products has been studied using X-ray diffraction, scanning electron microscopy and electron microprobe analysis. It has been established that the anode corrosion is induced by a surface electrochemical polarization and iron atom oxidation. Iron ions come into an exchange interaction with the fluoride components of the melted electrolyte, producing FeF2. The last interacts with oxyfluoride species transforming into the oxide forms: FeAl2O4, Fe3O4, Fe2O3. Due to the low solubility, the iron oxides are accumulated in the near-electrode sheath. The only small part of iron from anode migrates to cathode that makes an production of high purity aluminum of a real task. The alloy dopants are also subjected to corrosion in accordance with electromotive series resulting corrosion tunnels on the anode surface. The oxides are final compounds which collect in the same area. The corrosion products form an anode shell which is electronic conductor at electrolysis temperature. The electrolysis of alumina occurs beyond the corrosion shell. The rate limiting step in the corrosion is the electrolyte penetration through corrosion shell to the anode surface. The participation of the released oxygen in the corrosion has

  14. Plastic properties of tunsten produced by electrolysis of molten salts

    International Nuclear Information System (INIS)

    A study is made into bend ductility, microhardness and texture of tungsten produced by electrolysis of CsCl and KCl-NaF molten salts. The influence of texture and high temperature annealing on ductile-brittle transition temperature was determined using specimens of electrolytic tungsten coatings 0.3 mm thick. For tungsten specimens of perfect texture [111] transition temperature constitutes 250 deg C. High temperature annealing (1400 deg C 4 h) raises the temperature of ductile-brittle transition. This fact may be related to the process of impurity concentration on grain boundaries which length decreases on annealing. 8 refs., 3 figs.2 tabs

  15. Bio-Fuel Production Assisted with High Temperature Steam Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Grant Hawkes; James O' Brien; Michael McKellar

    2012-06-01

    Two hybrid energy processes that enable production of synthetic liquid fuels that are compatible with the existing conventional liquid transportation fuels infrastructure are presented. Using biomass as a renewable carbon source, and supplemental hydrogen from high-temperature steam electrolysis (HTSE), these two hybrid energy processes have the potential to provide a significant alternative petroleum source that could reduce dependence on imported oil. The first process discusses a hydropyrolysis unit with hydrogen addition from HTSE. Non-food biomass is pyrolyzed and converted to pyrolysis oil. The pyrolysis oil is upgraded with hydrogen addition from HTSE. This addition of hydrogen deoxygenates the pyrolysis oil and increases the pH to a tolerable level for transportation. The final product is synthetic crude that could then be transported to a refinery and input into the already used transportation fuel infrastructure. The second process discusses a process named Bio-Syntrolysis. The Bio-Syntrolysis process combines hydrogen from HTSE with CO from an oxygen-blown biomass gasifier that yields syngas to be used as a feedstock for synthesis of liquid synthetic crude. Conversion of syngas to liquid synthetic crude, using a biomass-based carbon source, expands the application of renewable energy beyond the grid to include transportation fuels. It can also contribute to grid stability associated with non-dispatchable power generation. The use of supplemental hydrogen from HTSE enables greater than 90% utilization of the biomass carbon content which is about 2.5 times higher than carbon utilization associated with traditional cellulosic ethanol production. If the electrical power source needed for HTSE is based on nuclear or renewable energy, the process is carbon neutral. INL has demonstrated improved biomass processing prior to gasification. Recyclable biomass in the form of crop residue or energy crops would serve as the feedstock for this process. A process model

  16. Magnetohydrodynamics simulation of 300 KA novel cell for aluminum electrolysis

    Directory of Open Access Journals (Sweden)

    Y. Song

    2015-10-01

    Full Text Available A novel cathode with cylindrical protrusions was presented to investigate the effect of protrusions on the electromagnetic field and flow field in the aluminum electrolysis cell. Results show that by using the novel cathode, the maximum horizontal electromagnetic force and velocity at 2/3 height of the metal pad were reduced by 21 % and 41 % respectively, and the metal - bath interface wave decreased by 0,69 cm. The metal pad flows around protrusions. Eddies due to boundary layer separation are beneficial to the dissolution of alumina.

  17. Considerations on electrolysis in electromembrane extraction of basic drugs

    Czech Academy of Sciences Publication Activity Database

    Šlampová, Andrea; Kubáň, Pavel; Boček, Petr

    Brno: Ústav analytické chemie AV ČR, v. v. i, 2015 - (Foret, F.; Křenková, J.; Drobníková, I.; Klepárník, K.), s. 198-201 ISBN 978-80-904959-3-7. [CECE 2015. International Interdisciplinary Meeting on Bioanalysis /12./. Brno (CZ), 21.09.2015-23.09.2015] R&D Projects: GA ČR(CZ) GA13-05762S Institutional support: RVO:68081715 Keywords : electrolysis * electromembrane extraction * basic drugs Subject RIV: CB - Analytical Chemistry, Separation http://www.ce-ce.org/CECE2015/CECE%202015%20proceedings_full.pdf

  18. The Effect of PFSA Membrane Compression on the Predicted Performance of a High Pressure PEM Electrolysis Cell

    DEFF Research Database (Denmark)

    Olesen, Anders Christian; Kær, Søren Knudsen

    layer at the anode, to withstand the mechanical compression, a conventional perfluorinated sulfonic acid (PFSA) membrane can be used as the electrolyte. Although PFSA membranes like Nafion exhibit high thermo-mechanical stability, water uptake and transport properties are significantly affected by......In the electrolysis of water it is convenient and advantageous to directly compress hydrogen at the cathode. This reduces system requirements and energy consumption associated with subsequent mechanical compression [1–3]. The simplest and most energy efficient system configuration is the so...... mechanical compression depending on the temperature, relative humidity and the amount of liquid water present [4]. Consequently, it is of great importance to accurately account for the physiochemical relationship between mechanical compression and equilibrium water uptake, when attempting to predict the...

  19. Method and system for purification of gas/liquid streams for fuel cells or electrolysis cells

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention provides in embodiments a method for purification of inlet gas/liquid streams in a fuel cell or electrolysis cell, the fuel cell or electrolysis cell comprising at least a first electrode, an electrolyte and a second electrode, the method comprising the steps of: - providing...... at least one scrubber in the gas/liquid stream at the inlet side of the first electrode of the fuel cell or electrolysis cell; and/or providing at least one scrubber in the gas/liquid stream at the inlet side of the second electrode of the fuel cell or electrolysis cell; and - purifying the gas...... purified with the at least one scrubber, with the proviso that the fuel cell or electrolysis cell is not a solid oxide cell....

  20. Process of treating cellulosic membrane and alkaline with membrane separator

    Science.gov (United States)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1970-01-01

    The improvement of water-soluble cellulose ether membranes for use as separators in concentrated alkaline battery cells is discussed. The process of contacting membranes with an aqueous alkali solution of concentration less than that of the alkali solution to be used in the battery but above that at which the membrane is soluble is described.