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Sample records for acid electrolyte solution

  1. Acidity of frozen electrolyte solutions.

    PubMed

    Robinson, Carmen; Boxe, C S; Guzman, M I; Colussi, A J; Hoffmann, M R

    2006-04-20

    Ice is selectively intolerant to impurities. A preponderance of implanted anions or cations generates electrical imbalances in ice grown from electrolyte solutions. Since the excess charges are ultimately neutralized via interfacial (H(+)/HO(-)) transport, the acidity of the unfrozen portion can change significantly and permanently. This insufficiently recognized phenomenon should critically affect rates and equilibria in frozen media. Here we report the effective (19)F NMR chemical shift of 3-fluorobenzoic acid as in situ probe of the acidity of extensively frozen electrolyte solutions. The sign and magnitude of the acidity changes associated with freezing are largely determined by specific ion combinations, but depend also on solute concentration and/or the extent of supercooling. NaCl solutions become more basic, those of (NH(4))(2)SO(4) or Na(2)SO(4) become more acidic, while solutions of the 2-(N-morpholino)ethanesulfonic acid zwitterion barely change their acidity upon freezing. We discuss how acidity scales based on solid-state NMR measurements could be used to assess the degree of ionization of weak acids and bases in frozen media. PMID:16610849

  2. ELECTROLYTIC REDUCTION OF NITRIC ACID SOLUTIONS

    DOEpatents

    Alter, H.W.; Barney, D.L.

    1958-09-30

    A process is presented for the treatment of radioactivc waste nitric acid solutions. The nitric acid solution is neutralized with an alkali metal hydroxide in an amount sufficient to precipitate insoluble hydroxides, and after separation of the precipitate the solution is electrolyzed to convert the alkali nitrate formed, to alkali hydroxide, gaseous ammonla and oxygen. The solution is then reusable after reducing the volume by evaporating the water and dissolved ammonia.

  3. Electrolytic recovery of copper and regeneration of nitric acid from a copper strip solution

    SciTech Connect

    Stewart, T.L.; Hartley, J.N.

    1985-01-01

    The fabrication of nuclear fuels involves stripping of a copper jacket with nitric acid. The waste acid, which contains 3.0 to 4.5 N nitric acid and 100 to 180 g/L copper, is currently discharged, neutralized, and disposed of in solar evaporation ponds. Alternative waste disposal and treatment methods including electrowinning are being investigated. Laboratory-scale electrowinning tests have been conducted in an air-sparged cell at current densities from 0.027 to 0.22 A/cm/sup 2/. The efficiency of copper recovery was improved by adding sulfamic acid or by cooling the electrolyte. Copper current efficiency ranged from 55% to 95%; energy consumption ranged from 1.8 to 6.6 kWh/kg Cu. Results of the laboratory-scale electrowinning tests are summarized. A brief economic comparison of an alternative waste disposal and acid recycle technique is presented.

  4. Wetting in electrolyte solutions.

    PubMed

    Ibagon, Ingrid; Bier, Markus; Dietrich, S

    2013-06-01

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

  5. Growth of thin, c-axis oriented Sr-doped LaP3O9 electrolyte membranes in condensed phosphoric acid solutions

    NASA Astrophysics Data System (ADS)

    Hatada, Naoyuki; Takahashi, Kota; Adachi, Yoshinobu; Uda, Tetsuya

    2016-08-01

    Proton-conducting Sr-doped LaP3O9 has potential application as electrolytes in intermediate temperature fuel cells, but reduction of the electrical resistance of the electrolyte membranes is necessary for practical applications. In this study, we focused on reducing the resistance by reducing the electrolyte thickness, while maintaining a preferable microstructure for proton conduction (c-axis orientation and absence of the small-crystal layer). Thin, c-axis oriented Sr-doped LaP3O9 membranes were successfully obtained in condensed phosphoric acid solutions by a novel "two-step precipitation method". In this method, Sr-doped LaP3O9 powder was artificially deposited on the surface of the carbon paper supports as seeds, and then columnar crystals were grown "downward" in the solutions. We expect that this method will be utilized to produce LaP3O9 electrolyte membranes with lower electrical resistance.

  6. Hydrogen-ion titrations of amino acids and proteins in solutions containing concentrated electrolyte

    SciTech Connect

    Fergg, F.; Kuehner, D.E.; Blanch, H.W.; Prausnitz, J.M.

    1994-12-01

    This report describes a first attempt to quantify the net charge as a function of solution pH for lysozyme and {alpha}-chymotrypsin at 0.1 M, 1.0 M and 3.0 M ionic strength, (IS). The calculations are based on the residue (titratable group) pK{sub a}`s in the amino-acid sequence of the protein. To determine these pK{sub a}`s, a simple theory was used which assumes that the pK{sub a}`s are independent from each other in the protein and are equal to their pK{sub a} values in free amino-acid solution (Independent-Site Theory, IST). Residue pK{sub a}`s were obtained from amino-acid hydrogen-ion titrations at three different KCl concentrations corresponding to 0.1M, 1.0M and 3.0M ionic strength. After construction of a suitable apparatus, the experimental procedure and data reduction were computerized to perform a large number of titrations. Most measured pK{sub a}`s showed high reproducibility (the difference of pK{sub a} values observed between two experiments was less than 0.05). For IS = 0.1M, observed pK{sub a}`s agreed with literature values to within a few hundredths of a pH unit. Furthermore, the ionic-strength dependence of the pK{sub a}`s followed the trends reported in the literature, viz. pK{sub a} values decrease with increasing ionic strength until they reach a minimum at about IS = 0.5M. At still higher IS, pK{sub a}`s increase as the ionic strength rises to 3M. The known pK{sub a}`s of all titratable groups in a protein were used with the IST to give a first approximation of how the protein net charge varies with pH at high ionic strength. A comparison of the titration curves based on the IST with experimental lysozyme and {alpha}-chymotrypsin titration data indicates acceptable agreement at IS = 0.1M. However, comparison of measured and calculated titration curves at IS = 1M and IS = 3M indicates only quantitative agreement.

  7. High conductivity electrolyte solutions and rechargeable cells incorporating such solutions

    DOEpatents

    Angell, Charles Austen; Zhang, Sheng-Shui; Xu, Kang

    1998-01-01

    This invention relates generally to electrolyte solvents for use in liquid or rubbery polymer electrolyte solutions as are used, for example, in electrochemical devices. More specifically, this invention relates to sulfonyl/phospho-compound electrolyte solvents and sulfonyl/phospho-compound electrolyte solutions incorporating such solvents.

  8. High conductivity electrolyte solutions and rechargeable cells incorporating such solutions

    DOEpatents

    Angell, C.A.; Zhang, S.S.; Xu, K.

    1998-10-20

    This invention relates generally to electrolyte solvents for use in liquid or rubbery polymer electrolyte solutions as are used, for example, in electrochemical devices. More specifically, this invention relates to sulfonyl/phospho-compound electrolyte solvents and sulfonyl/phospho-compound electrolyte solutions incorporating such solvents. 9 figs.

  9. Electro-oxidation of methanol on Pt(111) in acid solutions: effects of electrolyte anions during electrocatalytic reactions

    NASA Astrophysics Data System (ADS)

    Ogasawara, Hirohito; Ito, Masatoki

    1995-10-01

    The electro-oxidation of methanol on a Pt(111) surface in both sulfuric and perchloric acid solutions was investigated by combined apparatus under both ultra-high vacuum and electrochemical environments. In sulfuric acid solution, a strong lateral interaction was observed between adsorbed bisulfate and CO derived from methanol. Coadsorption of CO derived from methanol with bisulfate ion yielded a (√7 × √7)-R19.1°-CO-bisulfate structure. In perchloric acid solution, however, no lateral interaction between adsorbed CO and perchlorate was seen. The difference in reaction rates of methanol oxidation in both solutions was explained by these specific anion adsorption effects.

  10. Potentiometric investigation of the effect of the pH on the ionic transfer of some amino acids at the interface between two immiscible electrolyte solutions.

    PubMed

    Spătaru, Tanta; Spătaru, Nicolae; Bonciocat, Nicolae; Luca, Constantin

    2004-04-01

    The effect of the pH on the ionic transfer of glycine and beta-alanine at the interface between two immiscible electrolyte solutions (ITIES) was investigated by a simple potentiometric method. Upon addition of small amounts of solution containing the investigated amino acids, a variation of the potential drop across the interface was recorded, which was found to be pH-dependent. This behavior was explained in terms of a preferential orientation of the amino acid molecules at the ITIES, induced by the different lipoficility of the functional groups. The results enabled the measurement of this voltage variation to be used as the basis for a simple and rapid method for determining the isoelectric point of the investigated compounds. The agreement between the pH(i) values thus estimated and those reported in the literature suggests the possibility of using the method for the interpretation of processes occurring at the level of biological membranes. PMID:14990327

  11. Evaluation of organic acids as fuel cell electrolytes

    SciTech Connect

    Ahmad, J.; Nguyen, T.H.; Foley, R.T.

    1981-11-01

    The electrochemical behavior of methanesulfonic acid, ethanesulfonic acid, and sulfoacetic acid as fuel cell electrolytes was studied in half-cell at various temperatures. The rate of the electro-oxidation of hydrogen at 115/degree/C was very high in methanesulfonic acid. The rate of the electro-oxidation of propane in all three acids was low even at 135/degree/C. Further, there is evidence for adsorption of these acids on the platinum electrode. It is concluded that anhydrous sulfonic acids are not good electrolytes; water solutions are required. Sulfonic acids containing unprotected carbon-hydrogen bonds are adsorbed on platinum and probably decompose during electrolysis. 9 refs.

  12. Supersaturated Electrolyte Solutions: Theory and Experiment

    NASA Technical Reports Server (NTRS)

    Izmailov, Alexander F.; Myerson, Allan S.; Na, Han-Soo

    1995-01-01

    Highly supersaturated electrolyte solutions can be prepared and studied employing an electrodynamic levitator trap (ELT) technique. The ELT technique involves containerless suspension of a microdroplet thus eliminating dust, dirt, and container walls which normally cause heterogeneous nucleation. This allows very high supersaturations to be achieved. A theoretical study of the experimental results obtained for the water activity in microdroplets of various electrolyte solutions is based on the development of the Cahn-Hilliard formalism for electrolyte solutions. In the approach suggested the metastable state for electrolyte solutions is described in terms of the conserved order parameter omega(r,t) associated with fluctuations of the mean solute concentration n(sub 0). Parameters of the corresponding Ginzburg-Landau free energy functional which defines the dynamics of metastable state relaxation are determined and expressed through the experimentally measured quantities. A correspondence of 96-99 % between theory and experiment for all solutions studied was achieved and allowed the determination of an analytical expression for the spinodal concentration n(sub spin), and its calculation for various electrolyte solutions at 298 K. The assumption that subcritical solute clusters consist of the electrically neutral Bjerrum pairs has allowed both analytical and numerical investigation of the number-size N(sub c) of nucleation monomers (aggregates of the Bjerrum pairs) which are elementary units of the solute critical clusters. This has also allowed estimations for the surface tension Alpha, and equilibrium bulk energy Beta per solute molecule in the nucleation monomers. The dependence of these properties on the temperature T and on the solute concentration n(sub 0) through the entire metastable zone (from saturation concentration n(sub sat) to spinodal n(sub spin) is examined. It has been demonstrated that there are the following asymptotics: N(sub c), = I at spinodal

  13. Extraction of electrolytes from aqueous solutions and their spectrophotometric determination by use of acid-base chromoionophores in lipophylic solvents.

    PubMed

    Barberi, Paola; Giannetto, Marco; Mori, Giovanni

    2004-04-01

    The formation of non-absorbing complexes in an organic phase has been exploited for the spectrophotometric determination of ionic analytes in aqueous solutions. The method is based on liquid-liquid extraction of aqueous solution with lipophylic organic phases containing an acid-base chromoionophore, a neutral lypophilic ligand (neutral carrier) selective to the analyte and a cationic (or anionic) exchanger. The method avoids all difficulties of the preparation of the very thin membranes used in optodes, so that it can advantageously be used for the study of the role physical-chemical parameters of the system in order to optimize them and to prepare, if necessary, an optimized optode. Two lipophylic derivatives of Nile Blue and 4',5-dibromofluorescein have been synthesized, in order to ensure their permanence within organic phase. Two different neutral carriers previously characterized by us as ionophores for liquid-membrane Ion Selective Electrodes have been employed. Three different ionic exchangers have been tested. Furthermore, a model allowing the interpolation of experimental data and the determination of the thermodynamic constant of the ionic-exchange equilibrium has been developed and applied. PMID:15242090

  14. Polyethylene glycol-electrolyte solution (PEG-ES)

    MedlinePlus

    Polyethylene glycol-electrolyte solution (PEG-ES) is used to empty the colon (large intestine, bowel) before a ... Polyethylene glycol-electrolyte solution (PEG-ES) comes as a powder to mix with water and take by ...

  15. Abiotic reversible self-assembly of fulvic and humic acid aggregates in low electrolytic conductivity solutions by dynamic light scattering and zeta potential investigation.

    PubMed

    Esfahani, Milad Rabbani; Stretz, Holly A; Wells, Martha J M

    2015-12-15

    The aggregation of humic substances and their interaction with filtration media (membranes, soils) has implications for our understanding of membrane fouling during water treatment, the facilitated transport of contaminants, and the transport of organic matter through the microbial loop. To investigate the aggregation of fulvic and humic acids in low electrolytic conductivity solutions, laboratory studies of simulated environmental water samples as well as actual environmental water samples were examined. Intensity-, volume-, and number-based particle size distributions (PSDs) were obtained by dynamic light scattering. Aggregates were categorized into three ranges, i.e., 10-100 nm, 100-1000 nm, and >1 μm. Individual biomacromolecules and the aggregates between 10 nm and 1 μm were presumed to be precursors for the formation of a large 5-μm-sized-particle. The self-assembly of the large-in-volume, few-in-number, 5-μm-sized particle was observed in real-time and occurred in unfiltered samples and in samples filtered (0.45 μm) at a nominal size one order of magnitude smaller. The supramicrometer-sized particle formed, dissipated, and spontaneously re-formed over turbulent/quiescent cycles in the presence of sodium azide indicating reversible abiotic self-assembly. Zeta potential analyses demonstrated that colloidal stability increased as concentration increased. DLS studies of the environmental water samples were comparable to those of the simulated laboratory samples. The operational range of the instrumentation used in these experiments was 0.6 nm-6 μm; therefore, aggregates larger than 6 μm may exist in these solutions. PMID:26282742

  16. Additive for electrolyte of lead-acid batteries

    SciTech Connect

    Greene, R.M.

    1986-10-14

    This patent describes a lead-acid storage battery containing as an electrolyte for each cell, an aqueous sulfuric acid solution containing an activating amount of an additive comprising a mixture of an iron chelate and a magnesium salt or chelate. The chelates for the iron and magnesium are formed from the chelating agents which form 4 to 6 membered rings with the iron and magnesium and which contain a member of the group consisting of amine groups, phenol groups and aldehyde groups.

  17. Polarization of anthracite electrodes in electrolyte solutions

    SciTech Connect

    A.N. Lopanov; E.V. Blaido; O.V. Smirnova

    2007-10-15

    The regularities of the polarization of anthractie electrodes for the liberation of hydrogen from electrolyte (potassium chloride and hydrogen chloride) solutions were found, and electrode processes occurring at the surface of coals in the Fe{sup 2+}/Fe{sup 3+} redox system were studied. It was found that the deviations of standard electrode potentials from the equilibrium values of redox systems depend on the exchange current densities of electrochemical processes occurring at the surface of coal matter. Low transfer coefficients (0.04-0.051) for the discharge reaction of hydrogen ions on anthracites indicate that the reaction occurs under conditions close to those of an activationless process.

  18. Theory for Surface Structure of Electrolyte Solutions.

    NASA Astrophysics Data System (ADS)

    Nichols, Albert Loyd, III

    A theory is developed for the salt concentration profile and ion-ion correlations near surfaces of electrolyte solutions. We use the random phase approximation to study the primitive surface model employed by Onsager and Samaras, and others. In this model the chief technical complication is the correct treatment of image forces. We invent an exact rearrangement of the mathematical formulation of the problem which makes especially transparent the special case solutions (infinite dielectric constant mismatch) previously found. This reformulation guides an analytical solution for arbitrary dielectric constant mismatch between the two phases, subject to other assumptions adopted by previous workers. Similarly general results are derived for mixtures of ionic and dipolar solutes. These general results form the basis for extending our theoretical studies in several new directions. First, higher concentration corrections are investigated. It is shown that over an experimentally significant range of low concentrations for aqueous solutions the initial concentration correction to the Onsager-Samaras absorption has a negative definite sign. The theory, including concentration corrections, is compared to available computer simulation data, and close agreement is found for aqueous solutions below a few tenths molar. Second, the theory is developed to treat asymmetric electrolytes, and applied to ionic surfactants spread on water-hydrocarbon interfaces. Again, the theory accurately describes available experimental data. Third, the theory is broadened to acknowledge the solubility of the salt in both phases. It is found that this generalization changes the qualitative nature of the low concentration limiting law for the excess surface tension: the limiting behavior is changed from the (rho)ln(rho) dependence predicted by Onsager and Samaras to a more generally correct (rho)(' 1/2) dependence. Experimental data which might test this (rho)(' 1/2) behavior are not presently

  19. Ionometry in the analysis of electrolyte solutions (review)

    SciTech Connect

    Petrukhin, O.M.; Rogatinskaya, S.L.; Shipulo, E.V.

    1995-04-01

    The potential usefulness of ionometry in the analytical control of plating electrolytes, etching solutions, and waste effluents has been considered. Complete ionometric analysis of plating electrolytes and determination of metal cyanide complexes have been presented as examples. Ion-selective field-effect transistors (IEFT), semiconductor electrodes, and ISE pairs have been shown to have potential usefulness for the potentiometric titration of plating electrolytes.

  20. Wide electrochemical window solvents for use in electrochemical devices and electrolyte solutions incorporating such solvents

    DOEpatents

    Angell, Charles Austen; Zhang, Sheng-Shui; Xu, Kang

    1998-01-01

    The present invention relates to electrolyte solvents for use in liquid or rubbery electrolyte solutions. Specifically, this invention is directed to boron-containing electrolyte solvents and boron-containing electrolyte solutions.

  1. Electrophoretic mobility of particles in concentrated solutions of electrolytes

    SciTech Connect

    Deinega, Yu.F.; Polyakova, V.M.; Aleksandrova, L.N.

    1986-11-01

    The electrophoretic mobility of particles of phenol-formaldehyde and aniline-formaldehyde resins in zinc sulfate solutions has been investigated. It is shown that as the electrolyte concentration rises, the electrophoretic mobility falls, reaches a minimum, and then increases. A possible mechanism for the formation of an electric double layer on the surface of particles in concentrated solutions of electrolytes is proposed.

  2. Electrolyte Solutions and Specific Ion Effects on Interfaces

    ERIC Educational Resources Information Center

    Friedman, Ran

    2013-01-01

    Introductory general and physical chemistry courses often deal with colligative properties of solutions and do not discuss nonideal solutions in detail. Yet, a growing body of evidence reveals that even at physiological concentrations electrolyte solutions cannot be treated as ideal when a charged or partially charged solute (such as a protein) is…

  3. Ionic liquids behave as dilute electrolyte solutions

    PubMed Central

    Gebbie, Matthew A.; Valtiner, Markus; Banquy, Xavier; Fox, Eric T.; Henderson, Wesley A.; Israelachvili, Jacob N.

    2013-01-01

    We combine direct surface force measurements with thermodynamic arguments to demonstrate that pure ionic liquids are expected to behave as dilute weak electrolyte solutions, with typical effective dissociated ion concentrations of less than 0.1% at room temperature. We performed equilibrium force–distance measurements across the common ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][NTf2]) using a surface forces apparatus with in situ electrochemical control and quantitatively modeled these measurements using the van der Waals and electrostatic double-layer forces of the Derjaguin–Landau–Verwey–Overbeek theory with an additive repulsive steric (entropic) ion–surface binding force. Our results indicate that ionic liquids screen charged surfaces through the formation of both bound (Stern) and diffuse electric double layers, where the diffuse double layer is comprised of effectively dissociated ionic liquid ions. Additionally, we used the energetics of thermally dissociating ions in a dielectric medium to quantitatively predict the equilibrium for the effective dissociation reaction of [C4mim][NTf2] ions, in excellent agreement with the measured Debye length. Our results clearly demonstrate that, outside of the bound double layer, most of the ions in [C4mim][NTf2] are not effectively dissociated and thus do not contribute to electrostatic screening. We also provide a general, molecular-scale framework for designing ionic liquids with significantly increased dissociated charge densities via judiciously balancing ion pair interactions with bulk dielectric properties. Our results clear up several inconsistencies that have hampered scientific progress in this important area and guide the rational design of unique, high–free-ion density ionic liquids and ionic liquid blends. PMID:23716690

  4. Oral therapy with glucose electrolyte solution.

    PubMed

    Clements, M L; Levine, M M; Black, R E; Hughes, T P; Nalin, D R; Pizarro, D; Hirschhorn, N

    1980-07-01

    Doctors Kahn and Blum based their views on oral rehydration on only 7 cases, and they fail to provide their methodological details. In their letter on oral rehydration with UNICEF/WHO (United Nations International Children's Emergency Fund/World Health Organization) glucose electrolyte solution (GES), they maintain that hyperkalemia is a danger of GES therapy, that hypernatremia will be aggravated, that therapy should not last for longer than 24 hours, that after 24 hours monitoring of plasma potassium will be needed, and that except for developing countries where material milk is used, no plan of treatment has been proposed after the first 24 hours of rehydration. The experience of Kahn and Blum is at variance with extensive data from many carefully monitored balanced studies in infants treated with GES. GES is a potent medication and needs to be used properly. Guidelines for use are listed. Kahn and Blum fail to indicate whether their 7 patients comprised their entire treatment group or only those with biochemical or clinical problems. They also fail to indicate the degree of dehydration of the infants at onset of therapy or the extent of ongoing diarrheal losses, and they do not describe the precise treatment regimen. Their mean time of treatment -- 41 hours -- was particularly long. The hyperkalemia reported by Kahn and Blum may have resulted from excessive GES administration, without a source of free water, to infants having few diarrheal stools. Proper use of GES formula rapidly rehydrates 95-98% of mildly to severely dehydrated infants, irrespective of etiology. PMID:6104241

  5. Electrical characterization of proton conducting polymer electrolyte based on bio polymer with acid dopant

    NASA Astrophysics Data System (ADS)

    Kalaiselvimary, J.; Pradeepa, P.; Sowmya, G.; Edwinraj, S.; Prabhu, M. Ramesh

    2016-05-01

    This study describes the biodegradable acid doped films composed of chitosan and Perchloric acid with different ratios (2.5 wt %, 5 wt %, 7.5 wt %, 10 wt %) was prepared by the solution casting technique. The temperature dependence of the proton conductivity of complex electrolytes obeys the Arrhenius relationship. Proton conductivity of the prepared polymer electrolyte of the bio polymer with acid doped was measured to be approximately 5.90 × 10-4 Scm-1. The dielectric data were analyzed using Complex impedance Z*, Dielectric loss ɛ', Tangent loss for prepared polymer electrolyte membrane with the highest conductivity samples at various temperature.

  6. Apparent Ionic Charge in Electrolyte and Polyelectrolyte Solutions

    ERIC Educational Resources Information Center

    Magdelenat, H.; And Others

    1978-01-01

    Compares average displacements of charged particles under thermal motion alone with those obtained by the action of an external electric field to develop a concept of "apparent charge" to approximate actual structural charge in an electrolyte solution. (SL)

  7. Coalescence of bubbles in aqueous solutions of electrolytes

    SciTech Connect

    Weissenborn, P.K.; Pugh, R.J.

    1995-12-31

    Salt water has been known to float coal (without use of collector or frother) for over 50 years. The contrasting behavior of electrolytes in inhibiting coalescence of bubbles was explained by the positive and negative distribution of anions and cations at the gas/water interface. Further, the efficiency of electrolytes which do inhibit coalescence of gas bubbles can be linked to a counter ion hydration mechanism and the effect of electrolyte concentration on gas solubility. A correlation was found between the transition concentration of electrolyte needed to prevent the coalescence of bubbles and the reduction in gas solubility. Hence, the inhibition of bubble coalescence in electrolyte solutions appears to be linked with the utilization of water molecules in the hydration of cations and a consequent reduction of water available for gas solubility.

  8. Drag enhancement of aqueous electrolyte solutions in turbulent pipe flow.

    PubMed

    Doherty, Andrew P; Spedding, Peter L; Chen, John J J

    2010-04-22

    Detailed experimental results are presented for both laminar and turbulent flow of aqueous solutions in pipes of different diameters. Nonelectrolytes, such as sugar solutions followed the normal Moody pressure loss curves. Drag enhancement was demonstrated for turbulent flow of aqueous electrolyte solutions but not for laminar flow. The increased pressure drop for turbulent electrolyte flow was attributed to an electroviscous effect and a theory was developed to explain the drag enhancement. The increased pressure drop for the turbulent region of flow was shown to depend on the Debye length in the laminar sublayer on the pipe wall. Reasonable predictions of the increasing drag were obtained for both 1:1 and 2:1 electrolyte solutions. PMID:20337452

  9. Solubility of non-polar gases in electrolyte solutions

    NASA Technical Reports Server (NTRS)

    Walker, R. L., Jr.

    1970-01-01

    Solubility theory describes the effects of both concentration and temperature on solute activity coefficients. It predicts the salting-out effect and the decrease in solubility of non-polar gases with increased electrolyte concentration, and can be used to calculate heats of solution, entropies, and partial molal volumes of dissolved gases

  10. Features of anodic niobium oxide formation in aqueous-organic electrolyte solutions (influence of ethylene glycol)

    SciTech Connect

    Bairachnyi, B.I.; Gomozov, V.P.; Lyashok, L.V.; Glagolev, S.E.

    1992-02-10

    The formation of anodic oxide films (AOFs) on valve metals in electrolytes with different compositions has received little attention. Earlier investigations dealt mainly with AOF growth and properties in aqueous solutions of mineral and organic acids and salts. Less research was done on electrolytes containing aqueous-organic solvents. An empirically formulated electrolyte with a water/ethylene glycol mixture as the solvent is widely employed in forming the dielectric for semiconductor oxide capacitors (SOCs). The mechanism by which ethylene glycol acts on AOF properties is still not wholly clear. It has been found that AOFs produced in an ethylene glycol electrolyte are bilaminar, with the outer layer being less corrosion-resistant. The degradation resistance and crystalline phase content of AOFs have also been studied. The objective of the present study was to examine the effect of ethylene glycol as solvent on AOF formation on niobium.

  11. Acid and alkali doped PBI electrolyte in electrochemical system

    NASA Astrophysics Data System (ADS)

    Xing, Baozhong

    In this work the conductivity of blank PBI membrane, acid doped PBI and alkaline doped PBI was systematically studied. A new methodology for sorption kinetics study in electrolyte solution has been established by monitoring the conductivity change during the sorption process. The model of the doping process and mechanism of conductivity are proposed. The performance of PBI (doped under optimum conditions) in fuel cell as PEM was evaluated. The experimental results show that the blank PBI in acid solution is an ionic insulator. It clarified the long time confusion in this area. The acid doped PBI membrane is an ionic conductor. The conductivity increases with the concentration of the acid solution. In high concentration acid solution, the conductivity increases with the type of acid in the order: H2SO 4 > H3PO4 > HClO4 > HNO3 > HCl. The kinetics of the doping process was studied, by a continuous method. The ionic conductivity mechanism was established. The PBI membranes doped with H2SO4 and H3PO4 exhibit better performance than NafionRTM. The doped FBI has more resistance to CO poison. 3% CO in H2 has little effect on the H3PO 4 doped PBI membrane at 185°C. The conductivity of the alkali doped PBI membrane changes with the concentration of the alkaline solution and the type of the alkalis. The conductivity has a maximum in KOH and NaOH solution. The maximum conductivity in KOH is higher than in NaOH and LiOH. It is about 5 times of that of NafionRTM in alkaline solution. The two-step sorption process in alkaline solution was observed. The first step is the permeation process of the alkalis in the PBI membrane. The permeation is the results of diffusion and interaction. It is concluded that the permeation process is controlled by the rate of interaction between the alkali and PBI molecule. The second step is the relaxation process in the membrane. This step contributes more to the conductivity for the membrane than the first step. The ionic conductivity mechanism

  12. Diffusioosmosis of electrolyte solutions in a fine capillary slit.

    PubMed

    Ma, Hsien Chen; Keh, Huan J

    2006-06-01

    The steady diffusioosmotic flows of an electrolyte solution along a charged plane wall and in a capillary channel between two identical parallel charged plates generated by an imposed tangential concentration gradient are theoretically investigated. The plane walls may have either a constant surface potential or a constant surface charge density. The electrical double layers adjacent to the charged walls may have an arbitrary thickness and their electrostatic potential distributions are determined by the Poisson-Boltzmann equation. Solving a modified Navier-Stokes equation with the constraint of no net electric current arising from the cocurrent diffusion, electric migration, and diffusioosmotic convection of the electrolyte ions, the macroscopic electric field and the fluid velocity along the tangential direction induced by the imposed electrolyte concentration gradient are obtained semianalytically as a function of the lateral position in a self-consistent way. The direction of the diffusioosmotic flow relative to the concentration gradient is determined by the combination of the zeta potential (or surface charge density) of the wall, the properties of the electrolyte solution, and other relevant factors. For a given concentration gradient of an electrolyte along a plane wall, the magnitude of fluid velocity at a position in general increases with an increase in its electrokinetic distance from the wall, but there are exceptions. The effect of the lateral distribution of the induced tangential electric field and the relaxation effect in the double layer on the diffusioosmotic flow are found to be very significant. PMID:16364357

  13. Ion Pairing in Alkali Nitrate Electrolyte Solutions.

    PubMed

    Xie, Wen Jun; Zhang, Zhen; Gao, Yi Qin

    2016-03-10

    In this study, we investigate the thermodynamics of alkali nitrate salt solutions, especially the formation of contact ion pairs between alkali cation and nitrate anion. The ion-pairing propensity shows an order of LiNO3 < NaNO3 < KNO3. Such results explain the salt activity coefficients and suggest that the empirical "law of matching water affinity" is followed by these alkali nitrate salt solutions. The spatial patterns of contact ion pairs are different in the three salt solutions studied here: Li(+) forms the contact ion pair with only one oxygen of the nitrate while Na(+) and K(+) can also be shared by two oxygens of the nitrate. In reproducing the salt activity coefficient using Kirkwood-Buff theory, we find that it is essential to include electronic polarization for Li(+) which has a high charge density. The electronic continuum correction for nonpolarizable force field significantly improves the agreement between the calculated activity coefficients and their experimental values. This approach also improves the performance of the force field on salt solubility. From these two aspects, this study suggests that electronic continuum correction can be a promising approach to force-field development for ions with high charge densities. PMID:26901167

  14. Solvation of electrolytes and nonelectrolytes in aqueous solutions.

    PubMed

    Afanas'ev, V N

    2011-05-26

    A new theory of electrolyte and nonelectrolyte solutions has been developed which, unlike the Debye-Hückel method applicable for small concentrations only, makes it possible to estimate thermodynamic properties of a solution in a wide range of state parameters. One of the main novelties of the proposed theory is that it takes into account the dependence of solvation numbers upon the concentration of solution, and all changes occurring in the solution are connected with solvation of the stoichiometric mixture of electrolyte ions or molecules. The present paper proposes a rigorous thermodynamic analysis of hydration parameters of solutions. Ultrasound and densimetric measurements in combination with data on isobaric heat capacity have been used to study aqueous solutions of electrolytes NaNO3, KI, NaCl, KCl, MgCl2, and MgSO4 and of nonelectrolytes urea, urotropine, and acetonitrile. Structural characteristics of hydration complexes have been analyzed: hydration numbers h, the proper volume of the stoichiometric mixture of ions without hydration shells V(2h), compressibility β(1h), and the molar volume of water in hydration shells V(1h), their dependencies on concentration and temperature. It has been shown that for aqueous solutions the electric field of ions and molecules of nonelectrolytes has a greater influence on the temperature dependence of the molar volume of solution in hydration shells than a simple change of pressure. The cause of this effect may be due to the change in the dielectric permeability of water in the immediate vicinity of hydrated ions or molecules. The most studied compounds (NaCl, KCl, KI, MgCl2) have been studied in a wider range of solute concentrations of up to 4-5 mol/kg. Up to the complete solvation limit (CSL), the functions V(1h) = f(T) and β(1h) = f(T) are linear with a high correlation factor, and the dependence Y(K,S) = f(β1V1*) at all investigated concentrations of electrolytes and nonelectrolytes up to the CSL enables h and

  15. Diffusion of sulfuric acid in concentrated solutions

    SciTech Connect

    Umino, S.; Newman, J. )

    1993-08-01

    Aqueous sulfuric acid is an economically important chemical reagent. It is one of the largest volume chemical commodities, finding uses in fertilizer production, petroleum refining, extraction of metals from their ores, production of inorganic pigments, pickling of iron and steel, synthesis of surface-active agents, and as a reactant in the lead-acid storage battery. The restricted diffusion method was used to measure the differential diffusion coefficient of sulfuric acid in water at 25 C for the concentration range from 0.3 to 7.5 molar. The concentration gradients of diffusing species were observed by Rayleigh interferometry. Experimental transport data are analyzed with concentrated solution theory of electrolytes in order to elucidate macroscopic transport characteristics of sulfuric acid in terms of specific binary interactions in solution. Results indicate that the transport properties of sulfuric acid are determined by the hydrogen ion-water molecule.

  16. Index properties of illite-bentonite mixtures in electrolyte solutions

    SciTech Connect

    Sivapullaiah, P.V.; Savitha, S.

    1999-09-01

    Bentonite, commonly used for liner constructions in waste containment systems, possesses many limitations. Illuite or illite containing bentonite has been proposed as an alternative material for liner construction. Their properties in different types of pore fluids are important to assess the long-term performance of the liner. Further, the illite-bentonite interaction occurs and changes their properties. The effect of these interactions are modified in electrolyte solutions has been brought out in this paper. The index properties have been studied since they give an indication of their engineering properties. Due to reduction in the thickness of the diffused double layer and consequent particle aggregation in bentonite, the effect of clay-clay interaction reduces in electrolyte solutions. In electrolyte solutions, the liquid limit, the plasticity index, and free swell index of bentonite are lower than illite. The plasticity index of bentonite is further reduced in KCl solution. Clays with a higher plasticity index perform better to retain pollutants and reduce permeability. Hence, the presence of both illite and bentonite ensures better performance of the liner in different fluids.

  17. Thermodynamic properties of gases dissolved in electrolyte solutions.

    NASA Technical Reports Server (NTRS)

    Tiepel, E. W.; Gubbins, K. E.

    1973-01-01

    A method based on perturbation theory for mixtures is applied to the prediction of thermodynamic properties of gases dissolved in electrolyte solutions. The theory is compared with experimental data for the dependence of the solute activity coefficient on concentration, temperature, and pressure; calculations are included for partial molal enthalpy and volume of the dissolved gas. The theory is also compared with previous theories for salt effects and found to be superior. The calculations are best for salting-out systems. The qualitative feature of salting-in is predicted by the theory, but quantitative predictions are not satisfactory for such systems; this is attributed to approximations made in evaluating the perturbation terms.

  18. Measuring the state of charge of the electrolyte solution in a vanadium redox flow battery using a four-pole cell device

    NASA Astrophysics Data System (ADS)

    Ngamsai, Kittima; Arpornwichanop, Amornchai

    2015-12-01

    The decrease in the efficiency and capacity of a vanadium redox flow battery (VRB) caused by an electrolyte imbalance is an important impediment to its long-term operation. Knowing the state of charge (SOC) of an electrolyte solution can quantify the level of the electrolyte imbalance in the VRB. In this study, a four-pole cell device is devised and employed to predict the SOC. The proposed method directly measures the ionic resistance of the electrolyte solution and is sufficiently precise to be applied in real-time mode. Experimental studies on the effects of the operating current on the four-pole cell and the concentrations of vanadium and sulfuric acid in the electrolyte solution are carried out. The results show that the four-pole cell method can be utilized to measure the electrolyte SOC. The concentrations of vanadium and sulfuric acid in the electrolyte solution affect the ionic resistance of the solution. Regarding the capacity and efficiency of the VRB system, the results indicate that the electrical charge is determined from the concentration of vanadium and that the cell voltage depends on the concentration of sulfuric acid in the electrolyte solution. The decreased vanadium concentration and increased sulfuric acid concentration improves the cell voltage efficiency.

  19. Onsager's reciprocal relations in electrolyte solutions. I. Sedimentation and electroacoustics

    NASA Astrophysics Data System (ADS)

    Gourdin-Bertin, S.; Chassagne, C.; Bernard, O.; Jardat, M.

    2015-08-01

    In the framework of irreversible thermodynamics, we show that the sedimentation current in electrolyte solutions is mathematically equivalent to the low frequency limit of the ionic vibration current, appearing in the presence of an acoustic wave. This non-trivial result is obtained thanks to a careful choice of the reference frame used to express the mass fluxes in the context of electroacoustics. Coupled transport phenomena in electrolyte solutions can also be investigated in a mechanical framework, with a set of Newtonian equations for the dynamics of charged solutes. Both in the context of sedimentation and of electroacoustics, we show that the results obtained in the mechanical framework, in the ideal case (i.e., without interactions between ions), do satisfy the Onsager's reciprocal relations. We also derive the general relation between corrective forces accounting for ionic interactions which must be fulfilled so that the Onsager's reciprocal relations are verified. Finally, we show that no additional diffusion term needs to be taken into account in the flux of solutes (far from the walls), even if local concentration gradients exist, contrarily to what was done previously in the literature.

  20. Analysis of aromatic acids by nonaqueous capillary electrophoresis with ionic-liquid electrolytes.

    PubMed

    Lu, Yuanqi; Wang, Dunqing; Kong, Chunyan; Zhong, Hao; Breadmore, Michael C

    2014-12-01

    The separation of six kinds of aromatic acids by CZE with 1-ethyl-3-methylimidazolium chloride (EMIMCl) and 1-ethyl-3-methylimidazolium hydrogen sulfate (EMIMHSO4 ), two kinds of ionic liquids (ILs) as background electrolytes, and acetonitrile as solvent were investigated. The six kinds of aromatic acids can be separated under positive voltage with low IL concentration with either of the two ILs and separation with EMIMHSO4 is better in consideration of peak shapes and separation efficiency. But the migration order is different when the IL is different. Under negative voltage with high IL concentration, the six analytes can be separated with EMIMCl as background electrolytes and the migration order of the analytes is opposite to those with low concentration of EMIMCl as background electrolyte. The separations are based on the combination effects of heteroconjugation between the anions and cations in the ILs and the analytes, of which the heteroconjugation between the anions in the ILs and the analytes plays a dominant role. The heteroconjugation between the anions of the ILs and analytes is proton sensitive and only a very small amount of proticsolvents added into the electrolyte solution can harm the separation. When EMIMCl concentration is high, the heteroconjugation between the IL anions and the proton in the analytes make the effective mobility of the analytes much higher than the EOF and their migration direction reversed. Finally, the six aromatic acids in water samples were analyzed by nonaqueous CE with low concentration of EMIMHSO4 as background electrolytes with satisfactory results. PMID:25141838

  1. Mechanical behavior of a battery separator in electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Sheidaei, Azadeh; Xiao, Xinran; Huang, Xiaosong; Hitt, Jonathon

    2011-10-01

    The structural integrity of the separator is crucial to the abuse tolerance of a battery. To estimate its stress level in a battery, the mechanical property of the separator in situ in the battery environment must be known. This work investigated the tensile behavior of a single layer polypropylene (PP) separator in electrolyte solutions for Li-ion batteries using a dynamic mechanical analyzer (DMA). The measurements were carried out in both dry (ambient) and wet conditions for both the machine direction (MD) and the transverse direction (TD). In the wet condition, samples were submerged either in a DMC solvent or in a electrolyte solution of 1.1 M LiPF6 in EC/DMC (1/1 by volume). The DMA experiments were performed under uniaxial tension, creep, and frequency sweep modes. The results in all three modes demonstrated that the mechanical properties of the separator were significantly lower in wet conditions. For instance, in the MD, relative to the dry condition, the ratio of the Young's modulus was about 0.49 and 0.52 for DMC and 1.1 M LiPF6 in EC/DMC, respectively. The results indicate that the mechanical properties measured in dry condition using samples that had been preconditioned in solutions are not sufficient to represent the in situ material behavior.

  2. Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

    NASA Astrophysics Data System (ADS)

    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.

  3. A lithium ion battery using an aqueous electrolyte solution.

    PubMed

    Chang, Zheng; Li, Chunyang; Wang, Yanfang; Chen, Bingwei; Fu, Lijun; Zhu, Yusong; Zhang, Lixin; Wu, Yuping; Huang, Wei

    2016-01-01

    Energy and environmental pollution have become the two major problems in today's society. The development of green energy storage devices with good safety, high reliability, high energy density and low cost are urgently demanded. Here we report on a lithium ion battery using an aqueous electrolyte solution. It is built up by using graphite coated with gel polymer membrane and LISICON as the negative electrode, and LiFePO4 in aqueous solution as the positive electrode. Its average discharge voltage is up to 3.1 V and energy density based on the two electrode materials is 258 Wh kg(-1). It will be a promising energy storage system with good safety and efficient cooling effects. PMID:27328707

  4. A lithium ion battery using an aqueous electrolyte solution

    PubMed Central

    Chang, Zheng; Li, Chunyang; Wang, Yanfang; Chen, Bingwei; Fu, Lijun; Zhu, Yusong; Zhang, Lixin; Wu, Yuping; Huang, Wei

    2016-01-01

    Energy and environmental pollution have become the two major problems in today’s society. The development of green energy storage devices with good safety, high reliability, high energy density and low cost are urgently demanded. Here we report on a lithium ion battery using an aqueous electrolyte solution. It is built up by using graphite coated with gel polymer membrane and LISICON as the negative electrode, and LiFePO4 in aqueous solution as the positive electrode. Its average discharge voltage is up to 3.1 V and energy density based on the two electrode materials is 258 Wh kg−1. It will be a promising energy storage system with good safety and efficient cooling effects. PMID:27328707

  5. Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

    SciTech Connect

    Saksono, Nelson; Febiyanti, Irine Ayu Utami, Nissa; Ibrahim

    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.

  6. A lithium ion battery using an aqueous electrolyte solution

    NASA Astrophysics Data System (ADS)

    Chang, Zheng; Li, Chunyang; Wang, Yanfang; Chen, Bingwei; Fu, Lijun; Zhu, Yusong; Zhang, Lixin; Wu, Yuping; Huang, Wei

    2016-06-01

    Energy and environmental pollution have become the two major problems in today’s society. The development of green energy storage devices with good safety, high reliability, high energy density and low cost are urgently demanded. Here we report on a lithium ion battery using an aqueous electrolyte solution. It is built up by using graphite coated with gel polymer membrane and LISICON as the negative electrode, and LiFePO4 in aqueous solution as the positive electrode. Its average discharge voltage is up to 3.1 V and energy density based on the two electrode materials is 258 Wh kg‑1. It will be a promising energy storage system with good safety and efficient cooling effects.

  7. Modifications in structure and interaction of nanoparticle-protein-surfactant complexes in electrolyte solution

    NASA Astrophysics Data System (ADS)

    Mehan, Sumit; Kumar, S.; Aswal, V. K.; Schweins, R.

    2016-05-01

    SANS experiments of three-component system of anionic silica nanoparticles, anionic BSA protein and anionic SDS surfactants have been carried out without and with electrolyte in aqueous solution. In both the cases, the interaction of surfactant with protein results in formation of bead-necklace structure of protein-surfactant complexes in solution. These protein-surfactant complexes interact very differently with nanoparticles in absence and presence of electrolyte. In absence of electrolyte, nanoparticles remain in dispersed phase in solution, whereas with the addition of electrolyte the nanoparticles fractal aggregates are formed. SANS describes the phase behavior to be governed by competition of electrostatic and depletion interactions among the components solution.

  8. Hydration force between mica surfaces in aqueous KCl electrolyte solution.

    PubMed

    Leng, Yongsheng

    2012-03-27

    Liquid-vapor molecular dynamics simulations are performed to study the interaction forces between two mica surfaces in an aqueous KCl electrolyte solution. Strong repulsive hydration force is obtained within a distance of ~2 nm between the two mica surfaces, which cannot be explained by the continuum theory of double-layer repulsion. We find that this short-range repulsive hydration force is much stronger than the double-layer force between mica surfaces. Whereas the simulation system is much smaller than the surface force measurement system, fundamental mechanisms of repulsive hydration force are revealed. In particular, important features of the step-like force oscillatory behavior during normal compression and force hysteresis during retraction are observed. Detailed analysis of the ionic density distributions shows that the "forced adsorption" of diffusive K(+) ions onto mica surfaces during compression and the subsequent "slow desorption" of the absorbed K(+) ions from mica surfaces upon retraction are responsible for the hysteresis phenomenon. From a mechanics point of view, we attribute the load bearing capacity of the dense electrolyte to the very hard hydration shells of K(+) metal ions under confinement. We find that the hydrated K(+) ions and Cl(-) co-ions remain very diffusive in the aqueous film. Water molecules in the hydration layer are also very fluidic, in the sense that the diffusion constant of water molecules is less than its bulk value by at most 3 orders of magnitude under the extreme confinement. PMID:22369483

  9. Stability of Standard Electrolytic Conductivity Solutions in Glass Containers

    PubMed Central

    Shreiner, Rubina H.

    2002-01-01

    The stability of solutions having an electrolytic conductivity, κ, of 5 μS/cm to 100 000 μS/cm packaged in glass screw-cap bottles, glass serum bottles, and glass ampoules was monitored for 1 year to 2 years. The conductivity was determined by measuring the ac resistance of the solution. Mass loss was also monitored for solutions packaged in bottles. The solutions were prepared using KCl in water (κ ≥100 μS/cm) or KCl in 30 % (by mass) n-propanol 70 % (by mass) water (κ ≤ 15 μS/cm). The conductivity changes were compared by packaging type and by nominal κ. The main causes of the κ changes are evaporation (screw-cap bottles) and leaching (screw-cap bottles, serum bottles, and ampoules). Evaporation is determined from mass loss data; leaching occurs from the glass container with no change in mass. The choice of optimal packaging, which depends on the conductivity level, is the packaging in which κ changes the least with time. Ampoules are the most suitable packaging for standards having nominal κ values of 500 μS/cm to 100 000 μS/cm. Screw-cap bottles are most suitable for standards having a nominal κ of 5 μS/cm to 100 μS/cm.

  10. Study on Durability and Stability of an Aqueous Electrolyte Solution for Zinc Bromide Hybrid Flow Batteries

    NASA Astrophysics Data System (ADS)

    Kim, Donghyeon; Jeon, Joonhyeon

    2015-01-01

    Zinc-bromine flow battery using aqueous electrolyte has advantages of cost effective and high energy density, but there still remains a problem improving stability and durability of electrolyte materials during long-time cell operation. This paper focuses on providing a homogeneous aqueous solution for durability and stability of zinc bromide electrolyte. For performance experiments of conventional and proposed electrolyte solutions, detailed cyclic voltammetry (CV) measurements (at a scan rate of 20 mV s-1 in the range of -1.5 V~1.5 V) are carried out for 40 cycles and five kinds of electrolytes containing which has one of additives, such as (conventionally) zinc chloride, potassium chloride, (newly) lithium perchlorate, sodium perchlorate and zeolite-Y are compared with the 2.0 M ZnBr2 electrolyte, respectively. Experimental results show that using the proposed three additives provides higher anodic and cathodic peak current density of electrolytes than using other two conventional additives, and can lead to improved chemical reversibility of zinc bromide electrolyte. Especially, the solution of which the zeolite-Y added, shows enhanced electrochemical stability of zinc bromide electrolyte. Consequently, proposed electrolytes have a significant advantage in comparison with conventional electrolytes on higher stability and durability.

  11. Studies on the enhancement of solid electrolyte interphase formation on graphitized anodes in LiX-carbonate based electrolytes using Lewis acid additives for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Li, L. F.; Xie, B.; Lee, H. S.; Li, H.; Yang, X. Q.; McBreen, J.; Huang, X. J.

    The new electrolyte systems utilizing one type of Lewis acids, the boron based anion receptors (BBARs) with LiF, Li 2O, or Li 2O 2 in carbonate solutions have been developed and reported by us. These systems open up a new approach in developing non-aqueous electrolytes with higher operating voltage and less moisture sensitivity for lithium-ion batteries. However, the formation of a stable solid electrolyte interphase (SEI) layer on the graphitized anodes is a serious problem needs to be solved for these new electrolyte systems, especially when propylene carbonate (PC) is used as a co-solvent. Using lithium bis(oxalato)borate (LiBOB) as an additives, the SEI layer formation on mesophase carbon microbeads (MCMB) anode is significantly enhanced in these new electrolytes containing boron-based anion receptors, such as tris(pentafluorophenyl) borane, and lithium salt such as LiF, or lithium oxides such as Li 2O or Li 2O 2 in PC and dimethyl carbonate (DMC) solvents. The cells using these electrolytes and MCMB anodes cycled very well and the PC co-intercalation was suppressed. Fourier transform infrared spectroscopy (FTIR) studies show that one of the electrochemical decomposition products of LiBOB, lithium carbonate (Li 2CO 3), plays a quite important role in the stablizing SEI layer formation.

  12. Elucidating the Higher Stability of Vanadium (V) Cations in Mixed Acid Based Redox Flow Battery Electrolytes

    SciTech Connect

    Vijayakumar, M.; Wang, Wei; Nie, Zimin; Sprenkle, Vincent L.; Hu, Jian Z.

    2013-11-01

    The Vanadium (V) cation structures in mixed acid based electrolyte solution were analysed by density functional theory (DFT) based computational modelling and 51V and 35Cl Nuclear Magnetic Resonance (NMR) spectroscopy. The Vanadium (V) cation exists as di-nuclear [V2O3Cl2.6H2O]2+ compound at higher vanadium concentrations (≥1.75M). In particular, at high temperatures (>295K) this di-nuclear compound undergoes ligand exchange process with nearby solvent chlorine molecule and forms chlorine bonded [V2O3Cl2.6H2O]2+ compound. This chlorine bonded [V2O3Cl2.6H2O]2+ compound might be resistant to the de-protonation reaction which is the initial step in the precipitation reaction in Vanadium based electrolyte solutions. The combined theoretical and experimental approach reveals that formation of chlorine bonded [V2O3Cl2.6H2O]2+ compound might be central to the observed higher thermal stability of mixed acid based Vanadium (V) electrolyte solutions.

  13. Maintenance free lead acid batteries with immobilized electrolyte

    SciTech Connect

    Tuphorn, H.

    1984-10-01

    The reducing of antimony in lead-acid batteries in the last 10 years to optimize the maintenance of the batteries on the other hand was to the detriment of the cycle life. In contrast to antimonyfree batteries in conventional construction the immobilization of the electrolyte by gelatinizing permits the production of sealed batteries with highly improved cycle life, high charge acceptance and deep dischargeability. Moreover those batteries do not have a problem of electrolyte stratification. During charging the O/sub 2/-recombination is approximately 75% depending upon the battery size. Because of the O/sub 2/-recombination in this system a wider range of charging potentials of single cells in the battery takes place, which is characteristic of this system.

  14. Electrostatics of polymer translocation events in electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Buyukdagli, Sahin; Ala-Nissila, T.

    2016-07-01

    We develop an analytical theory that accounts for the image and surface charge interactions between a charged dielectric membrane and a DNA molecule translocating through the membrane. Translocation events through neutral carbon-based membranes are driven by a competition between the repulsive DNA-image-charge interactions and the attractive coupling between the DNA segments on the trans and the cis sides of the membrane. The latter effect is induced by the reduction of the coupling by the dielectric membrane. In strong salt solutions where the repulsive image-charge effects dominate the attractive trans-cis coupling, the DNA molecule encounters a translocation barrier of ≈10 kBT. In dilute electrolytes, the trans-cis coupling takes over image-charge forces and the membrane becomes a metastable attraction point that can trap translocating polymers over long time intervals. This mechanism can be used in translocation experiments in order to control DNA motion by tuning the salt concentration of the solution.

  15. Electrostatic interactions between charged dielectric particles in an electrolyte solution.

    PubMed

    Derbenev, Ivan N; Filippov, Anatoly V; Stace, Anthony J; Besley, Elena

    2016-08-28

    Theory is developed to address a significant problem of how two charged dielectric particles interact in the presence of a polarizable medium that is a dilute solution of a strong electrolyte. The electrostatic force is defined by characteristic parameters for the interacting particles (charge, radius, and dielectric constant) and for the medium (permittivity and Debye length), and is expressed in the form of a converging infinite series. The limiting case of weak screening and large inter-particle separation is considered, which corresponds to small (macro)ions that carry constant charge. The theory yields a solution in the limit of monopole and dipole terms that agrees exactly with existing analytical expressions, which are generally used to describe ion-ion and ion-molecular interactions in a medium. Results from the theory are compared with DLVO theory and with experimental measurements for the electrostatic force between two PMMA particles contained in a nonpolar solvent (hexadecane) with an added charge control agent. PMID:27586900

  16. Electrostatics of polymer translocation events in electrolyte solutions.

    PubMed

    Buyukdagli, Sahin; Ala-Nissila, T

    2016-07-01

    We develop an analytical theory that accounts for the image and surface charge interactions between a charged dielectric membrane and a DNA molecule translocating through the membrane. Translocation events through neutral carbon-based membranes are driven by a competition between the repulsive DNA-image-charge interactions and the attractive coupling between the DNA segments on the trans and the cis sides of the membrane. The latter effect is induced by the reduction of the coupling by the dielectric membrane. In strong salt solutions where the repulsive image-charge effects dominate the attractive trans-cis coupling, the DNA molecule encounters a translocation barrier of ≈10 kBT. In dilute electrolytes, the trans-cis coupling takes over image-charge forces and the membrane becomes a metastable attraction point that can trap translocating polymers over long time intervals. This mechanism can be used in translocation experiments in order to control DNA motion by tuning the salt concentration of the solution. PMID:27394120

  17. Generic transport coefficients of a confined electrolyte solution.

    PubMed

    Yoshida, Hiroaki; Mizuno, Hideyuki; Kinjo, Tomoyuki; Washizu, Hitoshi; Barrat, Jean-Louis

    2014-11-01

    Physical parameters characterizing electrokinetic transport in a confined electrolyte solution are reconstructed from the generic transport coefficients obtained within the classical nonequilibrium statistical thermodynamic framework. The electro-osmotic flow, the diffusio-osmotic flow, the osmotic current, as well as the pressure-driven Poiseuille-type flow, the electric conduction, and the ion diffusion are described by this set of transport coefficients. The reconstruction is demonstrated for an aqueous NaCl solution between two parallel charged surfaces with a nanoscale gap, by using the molecular dynamic (MD) simulations. A Green-Kubo approach is employed to evaluate the transport coefficients in the linear-response regime, and the fluxes induced by the pressure, electric, and chemical potential fields are compared with the results of nonequilibrium MD simulations. Using this numerical scheme, the influence of the salt concentration on the transport coefficients is investigated. Anomalous reversal of diffusio-osmotic current, as well as that of electro-osmotic flow, is observed at high surface charge densities and high added-salt concentrations. PMID:25493746

  18. Generic transport coefficients of a confined electrolyte solution

    NASA Astrophysics Data System (ADS)

    Yoshida, Hiroaki; Mizuno, Hideyuki; Kinjo, Tomoyuki; Washizu, Hitoshi; Barrat, Jean-Louis

    2014-11-01

    Physical parameters characterizing electrokinetic transport in a confined electrolyte solution are reconstructed from the generic transport coefficients obtained within the classical nonequilibrium statistical thermodynamic framework. The electro-osmotic flow, the diffusio-osmotic flow, the osmotic current, as well as the pressure-driven Poiseuille-type flow, the electric conduction, and the ion diffusion are described by this set of transport coefficients. The reconstruction is demonstrated for an aqueous NaCl solution between two parallel charged surfaces with a nanoscale gap, by using the molecular dynamic (MD) simulations. A Green-Kubo approach is employed to evaluate the transport coefficients in the linear-response regime, and the fluxes induced by the pressure, electric, and chemical potential fields are compared with the results of nonequilibrium MD simulations. Using this numerical scheme, the influence of the salt concentration on the transport coefficients is investigated. Anomalous reversal of diffusio-osmotic current, as well as that of electro-osmotic flow, is observed at high surface charge densities and high added-salt concentrations.

  19. A unifying mode-coupling theory for transport properties of electrolyte solutions. II. Results for equal-sized ions electrolytes.

    PubMed

    Aburto, Claudio Contreras; Nägele, Gerhard

    2013-10-01

    On the basis of a versatile mode-coupling theory (MCT) method developed in Paper I [C. Contreras Aburto and G. Nägele, J. Chem. Phys. 139, 134109 (2013)], we investigate the concentration dependence of conduction-diffusion linear transport properties for a symmetric binary electrolyte solution. The ions are treated in this method as charged Brownian spheres, and the solvent-mediated ion-ion hydrodynamic interactions are accounted for also in the ion atmosphere relaxation effect. By means of a simplified solution scheme, convenient semi-analytic MCT expressions are derived for the electrophoretic mobilities, and the molar conductivity, of an electrolyte mixture with equal-sized ions. These expressions reduce to the classical Debye-Falkenhagen-Onsager-Fuoss results in the limit of very low ion concentration. The MCT expressions are numerically evaluated for a binary electrolyte, and compared to experimental data and results by another theoretical method. Our analysis encloses, in addition, the electrolyte viscosity. To analyze the dynamic influence of the hydration shell, the significance of mixed slip-stick hydrodynamic surface boundary conditions, and the effect of solvent permeability are explored. For the stick boundary condition employed in the hydrodynamic diffusivity tensors, our theoretical results for the molar conductivity and viscosity of an aqueous 1:1 electrolyte are in good overall agreement with reported experimental data for aqueous NaCl solutions, for concentrations extending even up to two molar. PMID:24116555

  20. A unifying mode-coupling theory for transport properties of electrolyte solutions. II. Results for equal-sized ions electrolytes

    NASA Astrophysics Data System (ADS)

    Aburto, Claudio Contreras; Nägele, Gerhard

    2013-10-01

    On the basis of a versatile mode-coupling theory (MCT) method developed in Paper I [C. Contreras Aburto and G. Nägele, J. Chem. Phys. 139, 134109 (2013)], we investigate the concentration dependence of conduction-diffusion linear transport properties for a symmetric binary electrolyte solution. The ions are treated in this method as charged Brownian spheres, and the solvent-mediated ion-ion hydrodynamic interactions are accounted for also in the ion atmosphere relaxation effect. By means of a simplified solution scheme, convenient semi-analytic MCT expressions are derived for the electrophoretic mobilities, and the molar conductivity, of an electrolyte mixture with equal-sized ions. These expressions reduce to the classical Debye-Falkenhagen-Onsager-Fuoss results in the limit of very low ion concentration. The MCT expressions are numerically evaluated for a binary electrolyte, and compared to experimental data and results by another theoretical method. Our analysis encloses, in addition, the electrolyte viscosity. To analyze the dynamic influence of the hydration shell, the significance of mixed slip-stick hydrodynamic surface boundary conditions, and the effect of solvent permeability are explored. For the stick boundary condition employed in the hydrodynamic diffusivity tensors, our theoretical results for the molar conductivity and viscosity of an aqueous 1:1 electrolyte are in good overall agreement with reported experimental data for aqueous NaCl solutions, for concentrations extending even up to two molar.

  1. PREDICTING WATER ACTIVITY IN ELECTROLYTE SOLUTIONS WITH THE CISTERNAS-LAM MODEL

    SciTech Connect

    REYNOLDS JG; GREER DA; DISSELKAMP RL

    2011-03-01

    Water activity is an important parameter needed to predict the solubility of hydrated salts in Hanford nuclear waste supernatants. A number of models available in the scientific literature predict water activity from electrolyte solution composition. The Cisternas-Lam model is one of those models and has several advantages for nuclear waste application. One advantage is that it has a single electrolyte specific parameter that is temperature independent. Thus, this parameter can be determined from very limited data and extrapolated widely. The Cisternas-Lam model has five coefficients that are used for all aqueous electrolytes. The present study aims to determine if there is a substantial improvement in making all six coefficients electrolyte specific. The Cisternas-Lam model was fit to data for six major electrolytes in Hanford nuclear waste supernatants. The model was first fit to all data to determine the five global coefficients, when they were held constant for all electrolytes it yielded a substantially better fit. Subsequently, the model was fit to each electrolyte dataset separately, where all six coefficients were allowed to be electrolyte specific. Treating all six coefficients as electrolyte specific did not make sufficient difference, given the complexity of applying the electrolyte specific parameters to multi-solute systems. Revised water specific parameters, optimized to the electrolytes relevant to Hanford waste, are also reported.

  2. ELVIS: Multi-Electrolyte Aqueous Activity Model for Geothermal Solutions

    NASA Astrophysics Data System (ADS)

    Hingerl, F. F.; Wagner, T.; Driesner, T.; Kulik, D. A.; Kosakowski, G.

    2011-12-01

    High temperature, pressure, and fluid salinities render geochemical modeling of fluid-rock interactions in Enhanced Geothermal Systems a demanding task. Accurate prediction of fluid-mineral equilibria strongly depends on the availability of thermodynamic data and activity models. Typically, the Pitzer activity model is applied for geothermal fluids. A drawback of this model is the large number of parameters required to account for temperature and pressure dependencies, which significantly reduces computational efficiency of reactive transport simulations. In addition, most available parameterizations are valid only at vapor-saturated conditions. As an alternative we implemented the EUNIQUAC local composition model [2] that needs substantially fewer fitting parameters. However, the current EUNIQUAC model design does not include provision for high temperature (>150°C) applications and lacks a formulation for pressure dependence. Therefore, its application to geothermal conditions requires a re-formulation and re-fitting of the model. We developed a new tool termed GEMSFIT that allows generic fitting of activity models (for aqueous electrolyte and non-electrolyte solutions) and equations of state implemented in our geochemical equilibrium solver GEM-Selektor (http://gems.web.psi.ch). GEMSFIT combines a PostgreSQL database for storing and managing the datasets of experimental measurements and interaction parameters, the parallelized genetic algorithm toolbox of MATLAB° for the parameter fitting, and an interface to the numerical kernel of GEM-Selektor to access activity models and perform chemical equilibrium calculations. Benchmarking of the partly re-parameterized EUNIQUAC model against Pitzer revealed that the former is less accurate, which can result in incorrect predictions of mineral precipitation/dissolution. Consequently, we modified the EUNIQUAC model and concurrently introduced a pressure dependence to be able to fit experimental data over wide ranges of

  3. AN INVENTORY OF PHOTOGRAPHS OF ZINC ELECTRODEPOSITED FROM ACID ELECTROLYTES

    SciTech Connect

    Faltemier, J.L.; Jaksic, M.M.; Tsuda, T.; Tobias, C.W.

    1983-09-01

    Electrodeposition of zinc from acid electrolytes has been studied by several investigators in this laboratory. A large number of zinc deposits have been observed and photographs (SEM, micrographs, experimental equipment, and line drawings) have been prepared over the years 1976-1983. These photos are compiled in this LBL report to facilitate their future use by others. The tables in this report list the experimental conditions and corresponding identification numbers of photographs that are on file in the Photography Services Laboratory at the Lawrence Berkeley Laboratory. Several samples of these zinc deposits are shown.

  4. Phase diagram of a model of nanoparticles in electrolyte solutions.

    PubMed

    Li, Xiaofei; Lettieri, S; Wentzel, N; Gunton, J D

    2008-10-28

    We obtain accurate fluid-fluid coexistence curves for a recent simple model of interacting nanoparticles that includes the effects of ion-dispersion forces. It has been proposed that these ion-dispersion forces provide at least a partial explanation for the Hofmeister effect [M. Bostrom et al. Phys. Rev. Lett. 87, 168103 (2001)]. We study a model of aluminum oxide nanoparticle [Deniz et al., Colloids Surf. A 319, 98 (2008)] for three different electrolyte solutions with added salt type being sodium chloride, sodium iodide, and a nonpolarizable salt. We observe that the fluid-fluid coexistence curves depend substantially on the identity of added salt; this provides an efficient way of tuning the phase behavior of nanoparticles. The methods we employ include finite-size scaling (FSS), multicanonical histogram reweighting, and Gibbs ensemble methods. We show that, as expected, all three cases belong to the Ising universality class. The scaling fields and critical point parameters are obtained in the thermodynamic limit of infinite system size by extrapolation of our FSS results. PMID:19045253

  5. Metal Nickel Foam as an Efficient and Stable Electrode for Hydrogen Evolution Reaction in Acidic Electrolyte under Reasonable Overpotentials.

    PubMed

    Lu, Jia; Xiong, Tanli; Zhou, Weijia; Yang, Linjing; Tang, Zhenghua; Chen, Shaowei

    2016-03-01

    Acidic electrolytes are advantageous for water electrolysis in the production of hydrogen as there is a large supply of H(+) ions in the solution. In this study, with the applied overpotential larger than the equilibrium potential of Ni(0)/Ni(2+), Ni foam as HER electrode exhibits excellent and stable HER activity with an onset potential of -84 mV (vs RHE), a high current density of 10 mA cm(-2) at -210 mV (vs RHE), and prominent electrochemical durability (longer than 5 days) in acidic electrolyte. The results presented herein may has potential large-scale application in hydrogen energy production. PMID:26886556

  6. Continuous Renal Replacement Therapy for the Management of Acid-Base and Electrolyte Imbalances in Acute Kidney Injury.

    PubMed

    Yessayan, Lenar; Yee, Jerry; Frinak, Stan; Szamosfalvi, Balazs

    2016-05-01

    Continuous renal replacement therapy (CRRT) is used to manage electrolyte and acid-base imbalances in critically ill patients with acute kidney injury. Although a standard solution and prescription is acceptable in most clinical circumstances, specific disorders may require a tailored approach such as adjusting fluid composition, regulating CRRT dose, and using separate intravenous infusions to mitigate and correct these disturbances. Errors in fluid prescription, compounding, or delivery can be rapidly fatal. This article provides an overview of the principles of acid-base and electrolyte management using CRRT. PMID:27113697

  7. Thin wetting films from aqueous electrolyte solutions on SiC/Si wafer.

    PubMed

    Diakova, B; Filiatre, C; Platikanov, D; Foissy, A; Kaisheva, M

    2002-02-25

    The stability and rupture of thin wetting films from aqueous NaCl or Na2SO4 solutions of different concentrations on silicon carbide were investigated. The flat surface of SiC was obtained by plasma-enhanced chemical vapor deposition (PE-CVD) on top of a silicon wafer. The microinterferometric method was used for measuring the film thickness with time. The light reflectance was calculated as a function of film thickness for the four-layer system: air/aqueous solution/SiC/Si wafer. The microinterferometric experiments showed that films from aqueous NaCl and Na2SO4 solutions with concentrations up to 0.01 M were stable independent of the pre-treatment of the substrate. The pre-treatment of the SiC surface was crucial for the wetting film stability at electrolyte concentrations greater than 0.01 M. The films were unstable and ruptured if SiC was washed with 5% hydrofluoric acid and concentrated sulfuric acid, while they were stable if washing was in sulfuric acid only, without immersing SiC in HF. The average equilibrium film thickness was determined as a function of electrolyte concentration. Measurements of the electrokinetic potential zeta were performed by electrophores of SiC powder in 0.001 M NaCl. It was shown that silicon carbide surface was negatively charged. The theory of heterocoagulation was used for the interpretation of the results. Besides the DLVO forces, the structural disjoining pressure (both positive and negative) has been included in the analysis. PMID:11908786

  8. Electrolytes

    MedlinePlus

    ... part of blood that doesn't contain cells. Sodium, potassium, and chloride levels can also be measured as part of ... in urine. It test the levels of calcium, chloride, potassium, sodium, and other electrolytes.

  9. Electrolytes

    MedlinePlus

    ... part of blood that doesn't contain cells. Sodium, potassium, and chloride levels can also be measured as part of ... in urine. It test the levels of calcium, chloride, potassium, sodium, and other electrolytes. References Chernecky CC, Berger BJ. ...

  10. Experimental Investigation into the Transmembrane Electrical Potential of the Forward Osmosis Membrane Process in Electrolyte Solutions

    PubMed Central

    Bian, Lixia; Fang, Yanyan; Wang, Xiaolin

    2014-01-01

    The transmembrane electrical potential (TMEP) in a forward osmosis membrane process with a single electrolyte solution as the draw and feed solutions was investigated by experiments. The effects of membrane orientation, the electrolyte species (KCl, NaCl, MgCl2, and CaCl2), concentration and concentration ratio of solutions at both sides of membrane on water flux and TMEP were investigated. The results showed that the TMEPs at different membrane orientation cannot completely coincide, which confirmed the effect of membrane asymmetry. The ion diffusion coefficients significantly affected the TMEP across the membrane, with different patterns for different electrolytes and concentrations. PMID:24957177

  11. Growth behavior of anodic oxide formed by aluminum anodizing in glutaric and its derivative acid electrolytes

    NASA Astrophysics Data System (ADS)

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2014-12-01

    The growth behavior of anodic oxide films formed via anodizing in glutaric and its derivative acid solutions was investigated based on the acid dissociation constants of electrolytes. High-purity aluminum foils were anodized in glutaric, ketoglutaric, and acetonedicarboxylic acid solutions under various electrochemical conditions. A thin barrier anodic oxide film grew uniformly on the aluminum substrate by glutaric acid anodizing, and further anodizing caused the film to breakdown due to a high electric field. In contrast, an anodic porous alumina film with a submicrometer-scale cell diameter was successfully formed by ketoglutaric acid anodizing at 293 K. However, the increase and decrease in the temperature of the ketoglutaric acid resulted in non-uniform oxide growth and localized pitting corrosion of the aluminum substrate. An anodic porous alumina film could also be fabricated by acetonedicarboxylic acid anodizing due to the relatively low dissociation constants associated with the acid. Acid dissociation constants are an important factor for the fabrication of anodic porous alumina films.

  12. Effect of glutamine or glycine containing oral electrolyte solutions on mucosal morphology, clinical and biochemical findings, in calves with viral induced diarrhea.

    PubMed Central

    Naylor, J M; Leibel, T; Middleton, D M

    1997-01-01

    Twenty-one diarrheic calves were randomly assigned to 1 of 3 oral electrolyte treatments. The treatments were either a conventional oral electrolyte containing glycine (40 mmol/L) as the amino acid, an oral electrolyte in which glutamine (40 mmol/L) replaced glycine or an electrolyte in which high concentrations of glutamine (400 mmol/L) replaced glycine. The calves were monitored while on trial and at the end of the treatment they were euthanized and a necropsy was immediately performed. Calves fed the high glutamine electrolyte had more treatment failures (2/7 versus 0/7 for each of the other 2 treatments). There was a significant effect of type of electrolyte on fecal consistency. Calves fed the glycine containing electrolyte had the most solid feces. Duodenal villus height was significantly affected by the type of electrolyte: values (mean +/- 1 SEM) were 0.61 +/- 0.09, 0.46 +/- 0.05, and 0.59 +/- 0.07 mm for high glutamine, low glutamine and glycine electrolytes respectively. There was no significant difference in small intestinal surface area between groups. High glutamine treated calves had the greatest capacity to absorb xylose from the small intestine but this difference was not statistically significant. Overall, this trial does not suggest that substituting glutamine for glycine in oral electrolyte solutions improves treatment of diarrheic calves or speeds mucosal healing. PMID:9008800

  13. Sensitive bridge circuit measures conductance of low-conductivity electrolyte solutions

    NASA Technical Reports Server (NTRS)

    Schmidt, K.

    1967-01-01

    Compact bridge circuit measures sensitive and accurate conductance of low-conductivity electrolyte solutions. The bridge utilizes a phase sensitive detector to obtain a linear deflection of the null indicator relative to the measured conductance.

  14. Students' Misconceptions in Electrochemistry: Current Flow in Electrolyte Solutions and the Salt Bridge.

    ERIC Educational Resources Information Center

    Sanger, Michael J.; Greenbowe, Thomas J.

    1997-01-01

    Examines students' misconceptions and proposed mechanisms related to current flow in electrolyte solutions and the salt bridge. Confirms reported misconceptions and identifies several new ones. Discusses probable sources of misconceptions and some methods for preventing them. Contains 27 references. (JRH)

  15. Synthesis of novel acid electrolytes for phosphoric acid fuel cells

    NASA Astrophysics Data System (ADS)

    Adcock, James L.

    1988-11-01

    A 40 millimole per hour scale aerosol direct fluorination reactor was constructed. F-Methyl F-4-methoxybutanoate and F-4-methoxybutanoyl fluoride were synthesized by aerosol direct fluorination of methyl 4-methoxybutanoate. Basic hydrolysis of the perfluorinated derivatives produce sodium F-4 methoxybutanoate which was pyrolyzed to F-3-methoxy-1-propene. Purification and shipment of 33 grams of F-3-methoxy-1-propene followed. Syntheses by analogous methods allowed production and shipment of 5 grams of F-3-ethoxy 1-propene, 18 grams of F-3-(2-methoxy.ethoxy) 1-propene, and 37 grams of F-3,3-dimethyl 1-butene. Eighteen grams of F-2,2-dimethyl 1-chloropropane was produced directly and shipped. As suggested by other contractors, 5 grams of F-3-methoxy 1-iodopropane, and 5 grams of F-3-(2-methoxy.ethoxy) 1-iodopropane were produced by converting the respective precursor acid sodium salts produced for olefin synthesis to the silver salts and pyrolyzing them with iodine. Each of these compounds was prepared for the first time by the aerosol fluorination process during the course of the contract. These samples were provided to other Gas Research Institute (GRI) contractors for synthesis of perfluorinated sulfur (VI) and phosphorous (V) acids.

  16. Performance of AA5052 alloy anode in alkaline ethylene glycol electrolyte with dicarboxylic acids additives for aluminium-air batteries

    NASA Astrophysics Data System (ADS)

    Wang, DaPeng; Zhang, DaQuan; Lee, KangYong; Gao, LiXin

    2015-11-01

    Dicarboxylic acid compounds, i.e. succinic acid (SUA), adipic acid (ADA) and sebacic acid (SEA), are used as electrolyte additives in the alkaline ethylene glycol solution for AA5052 aluminium-air batteries. It shows that the addition of dicarboxylic acids lowers the hydrogen gas evolution rate of commercial AA5052 aluminium alloy anode. AA5052 aluminium alloy has wide potential window for electrochemical activity and better discharge performance in alkaline ethylene glycol solution containing dicarboxylic acid additives. ADA has the best inhibition effect for the self-corrosion of AA5052 anode among the three dicarboxylic acid additives. Fourier transform infrared spectroscopy (FT-IR) reveals that dicarboxylic acids and aluminium ions can form coordination complexes. Quantum chemical calculations shows that ADA has a smaller energy gap (ΔE, the energy difference between the lowest unoccupied orbital and the highest occupied orbital), indicating that ADA has the strongest interaction with aluminium ions.

  17. Synthesis and characterization of polyvinyl alcohol copolymer/phosphomolybdic acid-based crosslinked composite polymer electrolyte membranes

    NASA Astrophysics Data System (ADS)

    Anis, Arfat; Banthia, A. K.; Bandyopadhyay, S.

    Polymer electrolyte membrane fuel cells (PEMFCs) are very promising as future energy source due to their high-energy conversion efficiency and will help to solve the environmental concerns of energy production. Polymer electrolyte membrane (PEM) is recognised as the key element for an efficient PEMFC. Chemically crosslinked composite membranes consisting of a poly(vinyl alcohol-co-vinyl acetate-co-itaconic acid) (PVACO) and phosphomolybdic acid (PMA) have been prepared by solution casting and evaluated as proton conducting polymer electrolytes. The proton conductivity of the membranes is investigated as a function of PMA composition, crosslinking density and temperature. The membranes have also been characterized by FTIR spectroscopy, TGA, AFM and TEM. The proton conductivity of the composite membranes is of the order of 10 -3 S cm -1 and shows better resistance to methanol permeability than Nafion 117 under similar measurement conditions.

  18. Whole body acid-base and fluid-electrolyte balance: a mathematical model.

    PubMed

    Wolf, Matthew B

    2013-10-15

    A cellular compartment was added to our previous mathematical model of steady-state acid-base and fluid-electrolyte chemistry to gain further understanding and aid diagnosis of complex disorders involving cellular involvement in critically ill patients. An important hypothesis to be validated was that the thermodynamic, standard free-energy of cellular H(+) and Na(+) pumps remained constant under all conditions. In addition, a hydrostatic-osmotic pressure balance was assumed to describe fluid exchange between plasma and interstitial fluid, including incorporation of compliance curves of vascular and interstitial spaces. The description of the cellular compartment was validated by close comparison of measured and model-predicted cellular pH and electrolyte changes in vitro and in vivo. The new description of plasma-interstitial fluid exchange was validated using measured changes in fluid volumes after isoosmotic and hyperosmotic fluid infusions of NaCl and NaHCO3. The validated model was used to explain the role of cells in the mechanism of saline or dilutional acidosis and acid-base effects of acidic or basic fluid infusions and the acid-base disorder due to potassium depletion. A module was created that would allow users, who do not possess the software, to determine, for free, the results of fluid infusions and urinary losses of water and solutes to the whole body. PMID:23884137

  19. Electrostatic charge and interactions within carbon-nanotube nematic in electrolyte solution

    NASA Astrophysics Data System (ADS)

    Lee, Choong-Seop; Yakobson, Boris I.

    2004-03-01

    The lyotropic transitions from isotropic solution (I) to nematic liquid crystalline phases (N, N') of single-wall carbon nanotubes (SWNT) are guided by the volumetric fraction together with the electrostatic forces. The latter depends on charge transfer between the SWNT and the solvent-electrolyte, and can be studied in approach similar to Derjaguin-Landau-Verwey-Overbeek. A simple kinetic model for a charging mechanism of SWNT is proposed, which allows analytical treatment. We have explored the optimization of control parameters (equilibrium constants, temperature, pH, etc.) of the model to achieve the separation of densely packed SWNT-bundle (N) into array of spaced individual tubules (N'). Our results explain the observation in recent experiments [1] of the dispersion of SWNT in oleum (overconcentrated sulpheric acid) as well as the sudden collapse of such dispersion with small amount of water added. [1] M. Pasquali et al., Macromolecules (in press).

  20. Thermal and oxidation stability of organo-fluorine compound-mixed electrolyte solutions for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Nishikawa, Daiki; Nakajima, Tsuyoshi; Ohzawa, Yoshimi; Koh, Meiten; Yamauchi, Akiyoshi; Kagawa, Michiru; Aoyama, Hirokazu

    2013-12-01

    Thermal and oxidation stability of fluorine compound-mixed electrolyte solutions have been investigated. Charge/discharge behavior of natural graphite electrode has been also examined in the same electrolyte solutions. Fluorine compounds demonstrate much lower reactivity with metallic Li than ethylene carbonate/dimethyl carbonate. Fluorine compound-mixed electrolyte solutions show the lower reactivity with LiC6 and the smaller exothermic peaks due to decomposition of electrolyte solutions and surface films than original solutions without fluorine compound. Oxidation currents are also smaller in fluorine compound-mixed electrolyte solutions than in original ones. First coulombic efficiencies in fluorine compound-mixed electrolyte solutions are similar to those in original ethylene carbonate-based solutions except one case. Mixing of fluorine compounds highly increase first coulombic efficiencies of natural graphite electrode in propylene carbonate-containing solution.

  1. The contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using diamond anodes.

    PubMed

    Bensalah, Nasr; Dbira, Sondos; Bedoui, Ahmed

    2016-07-01

    In this work, the contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using boron-doped diamond (BDD) anodes was investigated in different electrolytes. A complete mineralization of cyanuric acid was obtained in NaCl; however lower degrees of mineralization of 70% and 40% were obtained in Na2SO4 and NaClO4, respectively. This can be explained by the nature of the oxidants electrogenerated in each electrolyte. It is clear that the contribution of active chlorine (Cl2, HClO, ClO(-)) electrogenerated from oxidation of chlorides on BDD is much more important in the electrolytic degradation of cyanuric acid than the persulfate and hydroxyl radicals produced by electro-oxidation of sulfate and water on BDD anodes. This could be explained by the high affinity of active chlorine towards nitrogen compounds. No organic intermediates were detected during the electrolytic degradation of cyanuric acid in any the electrolytes, which can be explained by their immediate depletion by hydroxyl radicals produced on the BDD surface. Nitrates and ammonium were the final products of electrolytic degradation of cyanuric acid on BDD anodes in all electrolytes. In addition, small amounts of chloramines were formed in the chloride medium. Low current density (≤10mA/cm(2)) and neutral medium (pH in the range 6-9) should be used for high efficiency electrolytic degradation and negligible formation of hazardous chlorate and perchlorate. PMID:27372125

  2. Role of hydration forces in the properties of electrolyte solutions in the bulk and at interfaces

    SciTech Connect

    Sushko, Maria L.; Rosso, Kevin M.

    2015-03-01

    We present a theoretical approach for modeling electrolyte solutions at interfaces that reaches into the mesoscale while retaining molecular detail. The total Hamiltonian of the system includes interactions arising from density and charge density (ion correlation) fluctuations, direct Coulomb interactions between ions, and at interfaces the image interactions, ion-solid and ion-water dispersion interactions. The model was validated against its ability to reproduce ion activity in 1:1 and 2:1 electrolyte solutions in the 0-2 M concentration range, its ability to capture the ion-specific effect in 1:1 electrolytes at the air-water interface, and solvent structure in a confined environment between hydrophobic surfaces, revealing the central role of ion hydration interactions in specific ion thermodynamic properties in the bulk solutions and at interfaces. The model is readily extensible to treat electrolyte interactions and forces across charged solid-water interfaces.

  3. Promoting solution phase discharge in Li-O2 batteries containing weakly solvating electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Gao, Xiangwen; Chen, Yuhui; Johnson, Lee; Bruce, Peter G.

    2016-08-01

    On discharge, the Li-O2 battery can form a Li2O2 film on the cathode surface, leading to low capacities, low rates and early cell death, or it can form Li2O2 particles in solution, leading to high capacities at relatively high rates and avoiding early cell death. Achieving discharge in solution is important and may be encouraged by the use of high donor or acceptor number solvents or salts that dissolve the LiO2 intermediate involved in the formation of Li2O2. However, the characteristics that make high donor or acceptor number solvents good (for example, high polarity) result in them being unstable towards LiO2 or Li2O2. Here we demonstrate that introduction of the additive 2,5-di-tert-butyl-1,4-benzoquinone (DBBQ) promotes solution phase formation of Li2O2 in low-polarity and weakly solvating electrolyte solutions. Importantly, it does so while simultaneously suppressing direct reduction to Li2O2 on the cathode surface, which would otherwise lead to Li2O2 film growth and premature cell death. It also halves the overpotential during discharge, increases the capacity 80- to 100-fold and enables rates >1 mA cmareal-2 for cathodes with capacities of >4 mAh cmareal-2. The DBBQ additive operates by a new mechanism that avoids the reactive LiO2 intermediate in solution.

  4. Comparison of interionic/intermolecular vibrational dynamics between ionic liquids and concentrated electrolyte solutions.

    PubMed

    Fujisawa, Tomotsumi; Nishikawa, Keiko; Shirota, Hideaki

    2009-12-28

    In this study, we have compared the interionic/intermolecular vibrational dynamics of ionic liquids (ILs) and concentrated electrolyte solutions measured by femtosecond optically heterodyne-detected Raman-induced Kerr effect spectroscopy. A typical anion in ILs, bis(trifluoromethanesulfonyl)amide ([NTf(2)](-)), has been chosen as the anion for the sample ILs and concentrated electrolyte solutions. ILs used in this study are 1-butyl-3-methylimidazolium, 1-butylpyridinium, N-butyl-N,N,N-triethylammonium, and 1-butyl-1-methylpyrrolidinium with [NTf(2)](-). Li[NTf(2)] solutions (approximately 3.3 M) of water, methanol, propylene carbonate, and poly(ethylene glycol) have been selected as control samples. Kerr transients of the ILs and electrolyte solutions show intra- and interionic/intermolecular vibrational dynamics followed by slow picosecond overdamped relaxation. Fourier transform Kerr spectra have shown a difference in the relative intensities of intraionic vibrational bands of [NTf(2)](-) (280-350 cm(-1)) between the ILs and electrolyte solutions. The origin of the difference is attributed to the change in the conformational equilibrium between cisoid and transoid forms of [NTf(2)](-), which is caused by a favorable stabilization of dipolar cisoid form due to Li(+) and dipolar solvent molecules in the electrolyte solutions. Low-frequency Kerr spectra (0-200 cm(-1)) exhibit unique features with the variation of cation and solvent species. The aromatic ILs have a prominent high-frequency librational motion at about 100 cm(-1) in contrast to the case for the nonaromatic ones. The common structure of the spectra observed at about 20 cm(-1) likely comes from an interionic motion of [NTf(2)](-). The nonaromatic ILs allow a fair comparison with the electrolyte solutions of propylene carbonate and poly(ethylene glycol) because of the structural similarities. The comparison based on the first moment of the interionic/intermolecular vibrational spectrum suggests the

  5. Comparison of interionic/intermolecular vibrational dynamics between ionic liquids and concentrated electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Fujisawa, Tomotsumi; Nishikawa, Keiko; Shirota, Hideaki

    2009-12-01

    In this study, we have compared the interionic/intermolecular vibrational dynamics of ionic liquids (ILs) and concentrated electrolyte solutions measured by femtosecond optically heterodyne-detected Raman-induced Kerr effect spectroscopy. A typical anion in ILs, bis(trifluoromethanesulfonyl)amide ([NTf2]-), has been chosen as the anion for the sample ILs and concentrated electrolyte solutions. ILs used in this study are 1-butyl-3-methylimidazolium, 1-butylpyridinium, N-butyl-N,N,N-triethylammonium, and 1-butyl-1-methylpyrrolidinium with [NTf2]-. Li[NTf2] solutions (˜3.3M) of water, methanol, propylene carbonate, and poly(ethylene glycol) have been selected as control samples. Kerr transients of the ILs and electrolyte solutions show intra- and interionic/intermolecular vibrational dynamics followed by slow picosecond overdamped relaxation. Fourier transform Kerr spectra have shown a difference in the relative intensities of intraionic vibrational bands of [NTf2]- (280-350 cm-1) between the ILs and electrolyte solutions. The origin of the difference is attributed to the change in the conformational equilibrium between cisoid and transoid forms of [NTf2]-, which is caused by a favorable stabilization of dipolar cisoid form due to Li+ and dipolar solvent molecules in the electrolyte solutions. Low-frequency Kerr spectra (0-200 cm-1) exhibit unique features with the variation of cation and solvent species. The aromatic ILs have a prominent high-frequency librational motion at about 100 cm-1 in contrast to the case for the nonaromatic ones. The common structure of the spectra observed at about 20 cm-1 likely comes from an interionic motion of [NTf2]-. The nonaromatic ILs allow a fair comparison with the electrolyte solutions of propylene carbonate and poly(ethylene glycol) because of the structural similarities. The comparison based on the first moment of the interionic/intermolecular vibrational spectrum suggests the stronger interionic/intermolecular interaction in

  6. Electric Interfacial Layer of Modified Cellulose Nanocrystals in Aqueous Electrolyte Solution: Predictions by the Molecular Theory of Solvation.

    PubMed

    Lyubimova, Olga; Stoyanov, Stanislav R; Gusarov, Sergey; Kovalenko, Andriy

    2015-06-30

    The X-ray crystal structure-based models of Iα cellulose nanocrystals (CNC), both pristine and containing surface sulfate groups with negative charge 0-0.34 e/nm(2) produced by sulfuric acid hydrolysis of softwood pulp, feature a highly polarized "crystal-like" charge distribution. We perform sampling using molecular dynamics (MD) of the structural relaxation of neutral pristine and negatively charged sulfated CNC of various lengths in explicit water solvent and then employ the statistical mechanical 3D-RISM-KH molecular theory of solvation to evaluate the solvation structure and thermodynamics of the relaxed CNC in ambient aqueous NaCl solution at a concentration of 0.0-0.25 mol/kg. The MD sampling induces a right-hand twist in CNC and rearranges its initially ordered structure with a macrodipole of high-density charges at the opposite faces into small local spots of alternating charge at each face. This surface charge rearrangement observed for both neutral and charged CNC significantly affects the distribution of ions around CNC in aqueous electrolyte solution. The solvation free energy (SFE) of charged sulfated CNC has a minimum at a particular electrolyte concentration depending on the surface charge density, whereas the SFE of neutral CNC increases linearly with NaCl concentration. The SFE contribution from Na(+) counterions exhibits behavior similar to the NaCl concentration dependence of the whole SFE. An analysis of the 3D maps of Na(+) density distributions shows that these model CNC particles exhibit the behavior of charged nanocolloids in aqueous electrolyte solution: an increase in electrolyte concentration shrinks the electric interfacial layer and weakens the effective repulsion between charged CNC particles. The 3D-RISM-KH method readily treats solvent and electrolyte of a given nature and concentration to predict effective interactions between CNC particles in electrolyte solution. We provide CNC structural models and a modeling procedure for

  7. Effect of electrolytes on wettability of glass surface using anionic and cationic surfactant solutions.

    PubMed

    Chaudhuri, Rajib Ghosh; Paria, Santanu

    2014-01-01

    Wetting behavior of a flat glass surface using pure nonionic, anionic, and cationic surfactants solutions has been studied by the dynamic contact angle (Wilhelmy plate) measurement technique. The advancing contact angle increases with the increasing concentration of surfactant and the value is maximum in the presence of cationic surfactant CTAB. The effect of different electrolytes in the presence of ionic surfactants was also studied to see the wetting behavior in the presence of electrolytes. The presence of electrolytes on ionic surfactant solutions significantly enhance the contact angle at very low concentration, which in turn lead to reduction in ionic surfactant requirement by more than 90% to achieve a particular contact angle. The effectiveness of electrolyte highly depends on the valance of counter ion. The reduction of ionic surfactant requirement is mostly useful for different applications such as flotation, and colloidal stability to reduce the production cost as well as environmental pollution. PMID:24183426

  8. System for absolute measurement of electrolytic conductivity in aqueous solutions based on van der Pauw's theory

    NASA Astrophysics Data System (ADS)

    Zhang, Bing; Lin, Zhen; Zhang, Xiao; Yu, Xiang; Wei, Jiali; Wang, Xiaoping

    2014-05-01

    Based on an innovative application of van der Pauw's theory, a system was developed for the absolute measurement of electrolytic conductivity in aqueous solutions. An electrolytic conductivity meter was designed that uses a four-electrode system with an axial-radial two-dimensional adjustment structure coupled to an ac voltage excitation source and signal collecting circuit. The measurement accuracy, resolution and repeatability of the measurement system were examined through a series of experiments. Moreover, the measurement system and a high-precision electrolytic conductivity meter were compared using some actual water samples.

  9. Stannous sulfate as an electrolyte additive for lead acid battery made from a novel ultrafine leady oxide

    NASA Astrophysics Data System (ADS)

    Wang, Qin; Liu, Jianwen; Yang, Danni; Yuan, Xiqing; Li, Lei; Zhu, Xinfeng; Zhang, Wei; Hu, Yucheng; Sun, Xiaojuan; Liang, Sha; Hu, Jingping; Kumar, R. Vasant; Yang, Jiakuan

    2015-07-01

    The effects of SnSO4 as an electrolyte additive on the microstructure of positive plate and electrochemical performance of lead acid battery made from a novel leady oxide are investigated. The novel leady oxide is synthesized through leaching of spent lead paste in citric acid solution. The novel leady oxides are used to prepare working electrode (WE) subjected to electrochemical cyclic voltammetry (CV) tests. Moreover, the novel leady oxides are used as active materials of positive plate assembled as a testing battery of 1.85 A h capacity. In CV tests, SEM/EDX results show that the major crystalline phase of the paste in WE after CV cycles is PbSO4. The larger column-shaped PbSO4 crystals easily generate in the paste of WE without an electrolyte additive of SnSO4. However, PbSO4 crystals significantly become smaller with the addition of SnSO4 in the electrolyte. In batteries testing, SEM results show that an electrolyte additive of SnSO4 could effectively decrease PbO2 particle size in the positive active materials of the teardown battery at the end of charging procedure. It is indicated that an electrolyte additive of SnSO4 could have a positive influence on restraining larger particles of irreversible sulfation in charge/discharge cycles of battery testing.

  10. Solution properties of polygalacturonic acid

    PubMed Central

    Stoddart, R. W.; Spires, I. P. C.; Tipton, K. F.

    1969-01-01

    1. The specimen of polygalacturonic acid used in these studies was shown to contain very little neutral sugar, methyl ester groups or ash, and only residues of galacturonic acid. Its electrophoretic homogeneity was examined in pyridine–acetic acid buffer at pH6·5 and in borate buffer at pH9·2. The distribution of effective particle weights was shown to be fairly narrow. 2. The pH-titration curve of the polymer gave a pK value of 3·7. 3. The interaction of the polymer with Ruthenium Red was studied and titration curves were obtained for the spectral shifts associated with the formation of a complex. 4. Optical-rotatory-dispersion studies showed that the Drude constant, λc, was dependent on pH. 5. Polygalacturonic acid was shown to display non-Newtonian properties in solution and to have an anomalously high relative specific viscosity at low concentrations. 6. Studies were made of the pH-dependence of the sedimentation coefficient of the polymer. 7. These results are discussed in terms of the structure of the molecule and their relevance to the properties of pectic substances. PMID:5343801

  11. Ions in hyaluronic acid solutions

    NASA Astrophysics Data System (ADS)

    Horkay, Ferenc; Basser, Peter J.; Londono, David J.; Hecht, Anne-Marie; Geissler, Erik

    2009-11-01

    Hyaluronic acid (HA) is an anionic biopolymer that is almost ubiquitous in biological tissues. An attempt is made to determine the dominant features that account for both its abundance and its multifunctional role, and which set it apart from other types of biopolymers. A combination of osmotic and scattering techniques is employed to quantify its dynamic and static properties in near-physiological solution conditions, where it is exposed both to mono- and divalent counterions. An equation of state is derived for the osmotic pressure Π in the semidilute concentration region, in terms of two variables, the polymer concentration c and the ionic strength J of the added salt, according to which Π =1.4×103c9/4/J3/4 kPa, where c and J are expressed in mole. Over the physiological ion concentration range, the effect of the sodium chloride and calcium chloride on the osmotic properties of HA solutions is fully accounted for by their contributions to the ionic strength. The absence of precipitation, even at high CaCl2 concentrations, distinguishes this molecule from other biopolymers such as DNA. Dynamic light scattering measurements reveal that the collective diffusion coefficient in HA solutions exceeds that in aqueous solutions of typical neutral polymers by a factor of approximately 5. This property ensures rapid adjustment to, and recovery from, stress applied to HA-containing tissue. Small angle x-ray scattering measurements confirm the absence of appreciable structural reorganization over the observed length scale range 10-1000 Å, as a result of calcium-sodium ion exchange. The scattered intensity in the transfer momentum range q >0.03 Å-1 varies as 1/q, indicating that the HA chain segments in semidilute solutions are linear over an extended concentration range. The osmotic compression modulus c ∂Π/∂c, a high value of which is a prerequisite in structural biopolymers, is several times greater than in typical neutral polymer solutions.

  12. A New Fe/V Redox Flow Battery Using Sulfuric/Chloric Mixed Acid Supporting Electrolyte

    SciTech Connect

    Wang, Wei; Nie, Zimin; Chen, Baowei; Chen, Feng; Luo, Qingtao; Wei, Xiaoliang; Xia, Guanguang; Skyllas-Kazacos, Maria; Li, Liyu; Yang, Zhenguo

    2012-04-01

    A redox flow battery using Fe2+/Fe3+ and V2+/V3+ redox couples in chloric/sulphuric mixed acid supporting electrolyte was investigated for potential stationary energy storage applications. The Fe/V redox flow cell using mixed reactant solutions operated within a voltage window of 0.5-1.35 V with a nearly 100% utilization ratio and demonstrated stable cycling over 100 cycles with energy efficiency > 80% and no capacity fading at room temperature. A 25% improvement in the discharge energy density of the Fe/V cell was achieved compared with the previous reported Fe/V cell using pure chloride acid supporting electrolyte. Stable performance was also achieved in the temperature range between 0 C and 50 C as well as using microporous separator as the membrane. The improved electrochemical performance at room temperature makes the Fe/V redox flow battery a promising option as a stationary energy storage device to enable renewable integration and stabilization of the electrical grid.

  13. Effect of salt identity on the phase diagram for a globularprotein in aqueous electrolyte solution

    SciTech Connect

    Bostrom, Mathias; Tavares, Frederico W.; Ninham, Barry W.; Prausnitz, John M.

    2006-02-22

    Monte Carlo simulations are used to establish the potential of mean force between two globular proteins in an aqueous electrolyte solution. This potential includes nonelectrostatic contributions arising from dispersion forces first, between the globular proteins, and second, between ions in solution and between each ion and the globular protein. These latter contributions are missing from standard models. The potential of mean force, obtained from simulation, is fitted to an analytic equation. Using our analytic potential of mean force and Barker-Henderson perturbation theory, we obtain phase diagrams for lysozyme solutions that include stable and metastable fluid-fluid and solid-fluid phases when the electrolyte is 0.2 M NaSCN or NaI or NaCl. The nature of the electrolyte has a significant effect on the phase diagram.

  14. Flow injection spectrophotometric determination of nitrate in electrolyte of lead-acid batteries.

    PubMed

    Rocha, F R; Nóbrega, J A

    1997-12-19

    Electrolytes of lead-acid batteries can contain several impurities that reduce battery performance and lifetime. Nitrate ions are among these species because they can be reduced to ammonium in the lead electrode. In this work, an analytical method was developed to determine this anion in electrolytes of batteries used in telephone systems, in which nitrate concentration must be lower than 10 mg l(-1). The procedure consists in the reduction to nitrite in a copperized cadmium column followed by Griess's modified reaction. Due to the high sensitivity of this methodology, a large dispersion flow diagram (dispersion coefficient = 27.8) was projected. Thus, it was possible to eliminate the Schlieren effect and to obtain a NH (3)NH (+)(4) buffer in the sample zone in a suitable pH for reduction reaction (pH congruent with 8). Negative interference due to iron(III) was overcome by addition of excess iron (200 mg l(-1)). A relocatable filter was used to remove iron(III) hydroxide precipitate. This avoided adsorption on the surface of the filings and increase of back pressure. The analytical frequency is 80 measurements/h and the detection limit was estimated as 0.3 mg l(-1) in a 99.7% confidence level. A 2.2% relative standard deviation was obtained in a repeatability study (n = 10) by using a 25 mg l(-1) nitrate solution in a 3.6 mol l(-1) sulfuric acid medium. Recoveries from 95.5 to 104% were obtained by spiking 5.00 or 10.0 mg l(-1) of nitrate in samples of battery electrolyte. PMID:18967001

  15. Towards Understanding the Poor Thermal Stability of V5+ Electrolyte Solution in Vanadium Redox Flow Batteries

    SciTech Connect

    Vijayakumar, M.; Li, Liyu; Graff, Gordon L.; Liu, Jun; Zhang, Huamin; Yang, Zhenguo; Hu, Jian Z.

    2011-04-01

    The V5+ electrolyte solution from vanadium redox flow batteries was studied by variable temperature 17O and 51V Nuclear Magnetic Resonance (NMR) spectroscopy and DFT based computational modeling. It was found that the V5+ species exist as hydrated penta co-ordinated vanadate ion, i.e. [VO2(H2O)3]1+. This hydrated structure is not stable at elevated temperature and change into neutral H3VO4 molecule via a deprotonation process. H3VO4 species is also knowingly unstable, leading to the observed V2O5 precipitation in V5+ electrolyte solutions.

  16. A residue level protein-protein interaction model in electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Song, Xueyu

    2014-03-01

    The osmotic second virial coefficients B2 are directly related to the solubility of protein molecules in electrolyte solutions and can be useful to narrow down the search parameter space of protein crystallization conditions. Using a residue level model of protein-protein interaction in electrolyte solutions B2 of bovine pancreatic trypsin inhibitor and lysozyme in various solution conditions such as salt concentration, pH and temperature are calculated using an extended Fast Multipole Methods in combination with the boundary element formulation. Overall, the calculated B2 are well correlated with the experimental observations for various solution conditions. In combination with our previous work on the binding affinity calculations of protein complexes it is demonstrated that our residue level model can be used as a reliable model to describe protein-protein interaction in solutions.

  17. Simple electrolyte solutions: Comparison of DRISM and molecular dynamics results for alkali halide solutions

    PubMed Central

    Joung, In Suk; Luchko, Tyler; Case, David A.

    2013-01-01

    Using the dielectrically consistent reference interaction site model (DRISM) of molecular solvation, we have calculated structural and thermodynamic information of alkali-halide salts in aqueous solution, as a function of salt concentration. The impact of varying the closure relation used with DRISM is investigated using the partial series expansion of order-n (PSE-n) family of closures, which includes the commonly used hypernetted-chain equation (HNC) and Kovalenko-Hirata closures. Results are compared to explicit molecular dynamics (MD) simulations, using the same force fields, and to experiment. The mean activity coefficients of ions predicted by DRISM agree well with experimental values at concentrations below 0.5 m, especially when using the HNC closure. As individual ion activities (and the corresponding solvation free energies) are not known from experiment, only DRISM and MD results are directly compared and found to have reasonably good agreement. The activity of water directly estimated from DRISM is nearly consistent with values derived from the DRISM ion activities and the Gibbs-Duhem equation, but the changes in the computed pressure as a function of salt concentration dominate these comparisons. Good agreement with experiment is obtained if these pressure changes are ignored. Radial distribution functions of NaCl solution at three concentrations were compared between DRISM and MD simulations. DRISM shows comparable water distribution around the cation, but water structures around the anion deviate from the MD results; this may also be related to the high pressure of the system. Despite some problems, DRISM-PSE-n is an effective tool for investigating thermodynamic properties of simple electrolytes. PMID:23387564

  18. The Interplay of Al and Mg Speciation in Advanced Mg Battery Electrolyte Solutions.

    PubMed

    See, Kimberly A; Chapman, Karena W; Zhu, Lingyang; Wiaderek, Kamila M; Borkiewicz, Olaf J; Barile, Christopher J; Chupas, Peter J; Gewirth, Andrew A

    2016-01-13

    Mg batteries are an attractive alternative to Li-based energy storage due to the possibility of higher volumetric capacities with the added advantage of using sustainable materials. A promising emerging electrolyte for Mg batteries is the magnesium aluminum chloride complex (MACC) which shows high Mg electrodeposition and stripping efficiencies and relatively high anodic stabilities. As prepared, MACC is inactive with respect to Mg deposition; however, efficient Mg electrodeposition can be achieved following an electrolytic conditioning process. Through the use of Raman spectroscopy, surface enhanced Raman spectroscopy, (27)Al and (35)Cl nuclear magnetic resonance spectroscopy, and pair distribution function analysis, we explore the active vs inactive complexes in the MACC electrolyte and demonstrate the codependence of Al and Mg speciation. These techniques report on significant changes occurring in the bulk speciation of the conditioned electrolyte relative to the as-prepared solution. Analysis shows that the active Mg complex in conditioned MACC is very likely the [Mg2(μ-Cl)3·6THF](+) complex that is observed in the solid state structure. Additionally, conditioning creates free Cl(-) in the electrolyte solution, and we suggest the free Cl(-) adsorbs at the electrode surface to enhance Mg electrodeposition. PMID:26636472

  19. MULTISPECIES CATION LEACHING DURING CONTINUOUS DISPLACEMENT OF ELECTROLYTE SOLUTIONS THROUGH SOIL COLUMNS

    EPA Science Inventory

    A model based upon concepts of multispecies ion chromatography and mobile-immobile water was developed to simulate the leaching of major soil cations during steady, continuous infiltration of electrolyte solutions into soil columns. The model assumes that a fraction of exchange s...

  20. Modeling of CO2 solubility in single and mixed electrolyte solutions using statistical associating fluid theory

    NASA Astrophysics Data System (ADS)

    Jiang, Hao; Panagiotopoulos, Athanassios Z.; Economou, Ioannis G.

    2016-03-01

    Statistical associating fluid theory (SAFT) is used to model CO2 solubilities in single and mixed electrolyte solutions. The proposed SAFT model implements an improved mean spherical approximation in the primitive model to represent the electrostatic interactions between ions, using a parameter K to correct the excess energies ("KMSA" for short). With the KMSA formalism, the proposed model is able to describe accurately mean ionic activity coefficients and liquid densities of electrolyte solutions including Na+, K+, Ca2+, Mg2+, Cl-, Br- and SO42- from 298.15 K to 473.15 K using mostly temperature independent parameters, with sole exception being the volume of anions. CO2 is modeled as a non-associating molecule, and temperature-dependent CO2-H2O and CO2-ion cross interactions are used to obtain CO2 solubilities in H2O and in single ion electrolyte solutions. Without any additional fitting parameters, CO2 solubilities in mixed electrolyte solutions and synthetic brines are predicted, in good agreement with experimental measurements.

  1. Comparative study of CoFeNx/C catalyst obtained by pyrolysis of hemin and cobalt porphyrin for catalytic oxygen reduction in alkaline and acidic electrolytes

    NASA Astrophysics Data System (ADS)

    Jiang, Rongzhong; Chu, Deryn

    2014-01-01

    Comparative studies of the oxygen reduction kinetics and mechanisms of CoFeNx/C catalysts have been conducted with rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) in aqueous acid and alkaline solutions, as well as acidic and alkaline polymer electrolytes. The CoFeNx/C catalysts in this study were obtained by the pyrolysis of hemin and a cobalt porphyrin. In an alkaline electrolyte, a larger electron transfer coefficient (0.63) was obtained in comparison to that in an acidic electrolyte (0.44), signifying a lower free energy barrier for oxygen reduction. The kinetic rate constant (2.69 × 10-2 cm s-1) for catalytic oxygen reduction in alkaline solution at 0.6 V (versus RHE) is almost 4 times larger than that in acidic solution (7.3 × 10-3 cm s-1). A synergetic catalytic mechanism is proposed. The overall reduction is a 4-electron reduction of oxygen. The obtained CoFeNx/C catalyst was further evaluated as a cathode catalyst in single fuel cells with acidic, neutral and alkaline electrolyte membranes. The order of the single cell performances either for power density or for stability is acidic > neutral > alkaline. The different behaviors of the CoFeNx/C catalyst in half cell and single cell are discussed.

  2. Frequency dispersion of the viscoelastic properties of solutions of electrolytes

    NASA Astrophysics Data System (ADS)

    Odinaev, S.; Akdodov, D. M.; Sharifov, N. Sh.; Mirzoaminov, Kh.

    2010-06-01

    Analytical expressions obtained earlier are used to numerically calculate the dynamic coefficients of the bulk ην(ω) and shear η s (ω) viscosity and the corresponding modules of their bulk K(ω) and shear μ(ω) elasticity at a certain choice of the model of solution structure in an approximation of the osmotic solution theory. The potential energy of the interaction between ions Φ ab ( r) was taken as the sum of the Lennard-Jones potential and the generalized Debye potential, taking into account the configuration and size of ions. In this approximation, the viscoelastic properties of the NaCl water solution were numerically calculated over a wide interval of change in the thermodynamic parameters and frequency ranges. Satisfactory agreement with the literature experimental data was obtained.

  3. Evaluating the performance enhancement of lead acid batteries by forced circulation of the electrolyte

    SciTech Connect

    Wicks, F.; Gilbert, T.J.

    1995-12-31

    Phenomena which may limit the performance of lead-acid batteries are the space charge and corresponding voltage gradient in the boundary between the plates and the electrolyte and also the stratification of the varying density electrolyte during the discharging and charging process. It has been suggested that forced circulation of the electrolyte could improve performance by minimizing these negative effects. However, the amount of benefit has been uncertain. This paper reviews previous work that has been performed to measure and model battery performance. It describes the experimental apparatus that was developed to demonstrate the difference between free and forced circulation of the electrolyte. It then presents experimental data that demonstrates substantial performance improvement results from forced circulation of the electrolyte. These improvements included a 16% improvement in energy output, along with higher power capability.

  4. A mechanistic study of copper electropolishing in phosphoric acid solutions

    NASA Astrophysics Data System (ADS)

    Mansson, Andrew

    The microelectronics industry is using copper as the interconnect material for microchips. A study of copper electropolishing is important for the process development of a new, low downforce approach, which is being developed to replace chemical mechanical polishing (CMP) of the copper overburden. A promising technology is a combination of electropolishing with conventional CMP. Electropolishing of copper in phosphoric acid has been studied for, more than 70 years. Previous work has shown that the polishing rate, as measured by current density is directly related to the viscosity of the electrolyte. Also, the limiting species is water. In this study, a multidimensional design of experiments was performed to develop an in-depth model of copper electropolishing. Phosphoric acid was mixed with alcohols of different molecular weight and related viscosity to investigate how the solvents' properties affected polishing. The alcohols used were methanol, ethanol, isopropanol, butanol, ethylene glycol, and glycerol. The limiting current densities and electrochemical behavior of each solution was measured by potentiodynamic and potentiostatic experiments. Also, the kinematic viscosity and density were measured to determine the dynamic viscosity to investigate the relationship of current density and viscosity. Water, methanol, ethanol, and isopropanol solutions were also examined at 20°C to 60°C. Next, the relative percentage of dissociated phosphoric acid was measured by Raman spectroscopy for each polishing solution. Raman spectroscopy was also used to measure the relative dissociation of phosphoric acid inside the polishing film. Additionally, wafers were electropolished and electrochemical mechanically polished to investigate the effects of the different solvents, fluid flow, current, and potential. The results of these experiments have shown that the molecular mass and the ability of the solvent to dissociate phosphoric acid are the primary electrolyte properties that

  5. Analytical and physicochemical studies of non-electrolyte solutions

    SciTech Connect

    Chien, C.J.

    1982-08-01

    High-precision gas-liquid chromatographic studies of N,N-dibutyl-2-ethylhexylamide (DBEHA), n-hexadecyl iodide, and 4-n-pentyl-4'-cyanobiphenyl (PCB) were carried out on the neat form and dissolved in n-hexadecane, n-octadecane, and tetra-n-butyltin. The microscopic partition hypothesis did not describe the behavior of these solvent mixtures. Conventional solutions theories failed to describe the experimental data derived from the DBEHA (haloalkane solutes) and nematic-phase PCB solvent systems. Complexation studies of N,N-dialkylamides (N,N-dimethyl formamide, N,N-dimethyl acetamide, and N,N-dimethyl thioformamide) by NMR showed that mixtures of these species with C/sub 6/H/sub 6/ or CCl/sub 4/ could not be described by simple equations. The window diagram strategy was successful for several solvents with packed columns of mixed-bed stationary phases. For intimate mixtures of phases (packed columns and glass-capillary columns), highly-ordered liquid crystals (nematic as well as isotropic regions) gave relative retentions for inert solutes (e.g., alkanes) different from highly-polarizable solutes (e.g., aromatics). Relative retentions with mixtures of solvents other than liquid crystals, in contrast, are expected to be predictable for purposes of application of the window diagram strategy. Replication of solute retentions with mixed-bed packed columns as well as with a capillary column containing an in-situ polymerized stationary phase were found to conform nearly exactly to one equation and its variants. 44 figures, 84 tables.

  6. Continuous electrolytic decarbonation and recovery of a carbonate salt solution from a metal-contaminated carbonate solution.

    PubMed

    Kim, Kwang-Wook; Kim, Yeon-Hwa; Lee, Se-Yoon; Lee, Eil-Hee; Song, Kyusuk; Song, Kee-Chan

    2009-11-15

    This work studied the characteristic changes of a continuous electrolytic decarbonation and recovery of a carbonate salt solution from a metal-contaminated carbonate solution with changes of operational variables in an electrolytic system which consisted of a cell-stacked electrolyzer equipped with a cation exchange membrane and a gas absorber. The system could completely recover the carbonate salt solution from a uranyl carbonato complex solution in a continuous operation. The cathodic feed rate could control the carbonate concentration of the recovered solution and it affected the most transient pH drop phenomenon of a well type within the gas absorber before a steady state was reached, which caused the possibility of a CO(2) gas slip from the gas absorber. The pH drop problem could be overcome by temporarily increasing the OH(-) concentration of the cathodic solution flowing down within the gas absorber only during the time required for a steady state to be obtained in the case without the addition of outside NaOH. An overshooting peak of the carbonate concentration in the recovered solution before a steady state was observed, which was ascribed to the decarbonation of the initial solution filled within the stacked cells by a redundant current leftover from the complete decarbonation of the feeding carbonate solution. PMID:19604641

  7. Nuclear magnetic resonance studies of supercooled aqueous electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Lang, E. W.; Bradl, S.; Fink, W.; Radkowitsch, H.; Girlich, D.

    1990-12-01

    The dynamic properties of water molecules coordinated to simple ions (alkali and alkali-earth halides) and hydrophobic ions (tetraalkylammonium (TAA) halides) in supercooled solutions have been investigated with NMR. The study of spin-lattice relaxation rates and self-diffusion coefficients as functions of temperature, pressure Larmor frequency and concentration reveals characteristic features of molecular motions close to the low-temperature limit of the metastable phase (percolation transition and glass transition) and provides certain details of the local arrangement of water molecules in the coordination sphere of these ions. The intramolecular flexibility of the alkyl chains of the hydrated TAA cations has been investigated also. The dynamics of the methyl group reorientation provide a sensitive probe of structural differences in these solutions.

  8. Isotonicity of liver and of kidney tissue in solutions of electrolytes.

    PubMed

    OPIE, E L

    1959-07-01

    Solutions of a wide variety of electrolytes, isotonic with liver or with kidney tissue, have approximately the same osmotic pressure as solutions of sodium chloride isotonic with tissues of the two organs respectively; that is, with solutions approximately twice as concentrated as the sodium chloride of mammalian blood plasma. The molar concentration of various electrolytes isotonic with liver or with kidney tissue immediately after its removal from the body is determined by the molecular weight, valency, and ion-dissociation of these electrolytes in accordance with the well known conditions of osmosis. The plasma membranes of liver and of kidney cells are imperfectly semipermeable to electrolytes, and those that enter the cell, though retarded in so doing, bring about injury which increases permeability to water. The osmotic activity of cells of mammalian liver and kidney immediately after their removal from the body resembles that of plant cells, egg cells of marine invertebrates, and mammalian red blood corpuscles and presumably represents a basic property of living cells by which osmotic pressure may be adjusted to functional need. PMID:13664872

  9. ISOTONICITY OF LIVER AND OF KIDNEY TISSUE IN SOLUTIONS OF ELECTROLYTES

    PubMed Central

    Opie, Eugene L.

    1959-01-01

    Solutions of a wide variety of electrolytes, isotonic with liver or with kidney tissue, have approximately the same osmotic pressure as solutions of sodium chloride isotonic with tissues of the two organs respectively; that is, with solutions approximately twice as concentrated as the sodium chloride of mammalian blood plasma. The molar concentration of various electrolytes isotonic with liver or with kidney tissue immediately after its removal from the body is determined by the molecular weight, valency, and ion-dissociation of these electrolytes in accordance with the well known conditions of osmosis. The plasma membranes of liver and of kidney cells are imperfectly semipermeable to electrolytes, and those that enter the cell, though retarded in so doing, bring about injury which increases permeability to water. The osmotic activity of cells of mammalian liver and kidney immediately after their removal from the body resembles that of plant cells, egg cells of marine invertebrates, and mammalian red blood corpuscles and presumably represents a basic property of living cells by which osmotic pressure may be adjusted to functional need. PMID:13664872

  10. Electrophoretic mobility of oil droplets in electrolyte and surfactant solutions.

    PubMed

    Wuzhang, Jiachen; Song, Yongxin; Sun, Runzhe; Pan, Xinxiang; Li, Dongqing

    2015-10-01

    Electrophoretic mobility of oil droplets of micron sizes in PBS and ionic surfactant solutions was measured in this paper. The experimental results show that, in addition to the applied electric field, the speed and the direction of electrophoretic motion of oil droplets depend on the surfactant concentration and on if the droplet is in negatively charged SDS solutions or in positively charged hexadecyltrimethylammonium bromide (CTAB) solutions. The absolute value of the electrophoretic mobility increases with increased surfactant concentration before the surfactant concentration reaches to the CMC. It was also found that there are two vortices around the oil droplet under the applied electric field. The size of the vortices changes with the surfactant and with the electric field. The vortices around the droplet directly affect the drag of the flow field to the droplet motion and should be considered in the studies of electrophoretic mobility of oil droplets. The existence of the vortices will also influence the determination and the interpretation of the zeta potential of the oil droplets based on the measured mobility data. PMID:26140616

  11. Nitric acid recovery from waste solutions

    DOEpatents

    Wilson, A. S.

    1959-04-14

    The recovery of nitric acid from aqueous nitrate solutions containing fission products as impurities is described. It is desirable to subject such solutions to concentration by evaporation since nitric acid is regenerated thereby. A difficulty, however, is that the highly radioactive fission product ruthenium is volatilized together with the nitric acid. It has been found that by adding nitrous acid, ruthenium volatilization is suppressed and reduced to a negligible degree so that the distillate obtained is practically free of ruthenium.

  12. Electrified microscopic and conventional interfaces between two immiscible electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Vanysek, Petr

    1991-06-01

    Transport studies on interfaces between immiscible phases bridges the field of heterogeneous electrode electrochemistry and that of homogeneous solution chemistry. Early work on liquid/liquid boundary was concerned with large area (order of a square centimeter) interfaces. Recent studies investigate phenomena on interfaces rendered in pores, capillaries, and small holes. The behavior of such interfaces in the presence of dodecyl sulfate, forming micelles, is investigated. Voltammetry and amperometry on these small interfaces reveals that the accompanying voltammetric characteristics are similar to that of metal ultramicroelectrodes. Potentiometric studies of dodecyl sulfate on water/nitrobenzene and aqueous polymer immiscible interfaces allow determination of critical micelle concentration.

  13. Dielectric relaxation of electrolyte solutions using terahertz transmission spectroscopy

    NASA Astrophysics Data System (ADS)

    Asaki, M. L. T.; Redondo, A.; Zawodzinski, T. A.; Taylor, A. J.

    2002-05-01

    We use terahertz (THz) transmission spectroscopy to obtain the frequency dependent complex dielectric constants of water, methanol, and propylene carbonate, and solutions of lithium salts in these solvents. The behavior of the pure solvents is modeled with either two (water) or three (methanol and propylene carbonate) Debye relaxations. We discuss the effects of ionic solvation on the relaxation behavior of the solvents in terms of modifications to the values of the Debye parameters of the pure solvents. In this way we obtain estimates for numbers of irrotationally bound solvent molecules, the numbers of bonds broken or formed, and the effects of ions on the higher-frequency relaxations.

  14. A portable air-aluminum power source with an alkaline electrolytic solution

    NASA Astrophysics Data System (ADS)

    Alekseenko, S. V.; Galkin, P. S.; Kashinskii, O. N.; Markovich, D. M.; Novopashin, S. A.; Randin, V. V.; Kharlamov, S. M.

    2014-04-01

    The results from development of a portable air-aluminum chemical power source (AA CPS) with an alkaline electrolytic solution without any additional service circuits are presented. The feasibility of making air cathodes on the basis of a metal-carbon composite produced by the plasma method has been shown. Special features of the operational conditions of a portable AA CPS have been investigated. It has been found that the aluminum cathode passivation when aluminum hydroxide precipitates from a solution significantly restricts the specific capacity of such power sources. It was shown that it is possible to overcome the anode passivation and to considerably increase the specific capacity of an AA CPS with an alkaline electrolytic solution by means of modifying an anode alloy.

  15. Co/Mo bimetallic addition to electrolytic manganese dioxide for oxygen generation in acid medium.

    PubMed

    Delgado, Dario; Minakshi, Manickam; McGinnity, Justin; Kim, Dong-Jin

    2015-01-01

    An efficient electrocatalyst comprising inexpensive and earth-abundant materials for the oxygen evolution reaction (OER) is crucial for the development of water electrolysis. In this work, in-situ addition of cobalt/molybdenum ions to the electrolytic manganese dioxide has been shown to be beneficial for the OER in acid solution as its overpotential performed better (305 mV) than that of the commercial DSA(®) (341 mV) at 100 mA cm(-2). The OER was investigated at ambient temperature in 2 M H2SO4 solution on the modified EMD (MnMoCoO) electrodes. The energy efficiency of the MnMoCoO electrodes improved significantly with the amount of Co in the plating solution. For the electrodeposited catalysts, physico-chemical and electrochemical measurements were conducted including static overpotentials. The better performance of the modified EMD was attributed to an improved charge transfer resistance (Rct; 0.290 Ω cm(2)), average roughness factor (rf; 429) and decrease in water content in the electrodeposited catalysts. The kinetic parameters obtained on MnMoCoO catalysts were compared and discussed according to the cobalt concentration. PMID:26469204

  16. Co/Mo bimetallic addition to electrolytic manganese dioxide for oxygen generation in acid medium

    PubMed Central

    Delgado, Dario; Minakshi, Manickam; McGinnity, Justin; Kim, Dong-Jin

    2015-01-01

    An efficient electrocatalyst comprising inexpensive and earth-abundant materials for the oxygen evolution reaction (OER) is crucial for the development of water electrolysis. In this work, in-situ addition of cobalt/molybdenum ions to the electrolytic manganese dioxide has been shown to be beneficial for the OER in acid solution as its overpotential performed better (305 mV) than that of the commercial DSA® (341 mV) at 100 mA cm−2. The OER was investigated at ambient temperature in 2 M H2SO4 solution on the modified EMD (MnMoCoO) electrodes. The energy efficiency of the MnMoCoO electrodes improved significantly with the amount of Co in the plating solution. For the electrodeposited catalysts, physico-chemical and electrochemical measurements were conducted including static overpotentials. The better performance of the modified EMD was attributed to an improved charge transfer resistance (Rct; 0.290 Ω cm2), average roughness factor (rf; 429) and decrease in water content in the electrodeposited catalysts. The kinetic parameters obtained on MnMoCoO catalysts were compared and discussed according to the cobalt concentration. PMID:26469204

  17. Co/Mo bimetallic addition to electrolytic manganese dioxide for oxygen generation in acid medium

    NASA Astrophysics Data System (ADS)

    Delgado, Dario; Minakshi, Manickam; McGinnity, Justin; Kim, Dong-Jin

    2015-10-01

    An efficient electrocatalyst comprising inexpensive and earth-abundant materials for the oxygen evolution reaction (OER) is crucial for the development of water electrolysis. In this work, in-situ addition of cobalt/molybdenum ions to the electrolytic manganese dioxide has been shown to be beneficial for the OER in acid solution as its overpotential performed better (305 mV) than that of the commercial DSA® (341 mV) at 100 mA cm-2. The OER was investigated at ambient temperature in 2 M H2SO4 solution on the modified EMD (MnMoCoO) electrodes. The energy efficiency of the MnMoCoO electrodes improved significantly with the amount of Co in the plating solution. For the electrodeposited catalysts, physico-chemical and electrochemical measurements were conducted including static overpotentials. The better performance of the modified EMD was attributed to an improved charge transfer resistance (Rct; 0.290 Ω cm2), average roughness factor (rf; 429) and decrease in water content in the electrodeposited catalysts. The kinetic parameters obtained on MnMoCoO catalysts were compared and discussed according to the cobalt concentration.

  18. Unravelling the anomalous dielectric permittivity of nanoconfined electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Renou, Richard; Szymczyk, Anthony; Ghoufi, Aziz

    2015-04-01

    The dielectric properties of sodium chloride solutions confined in a hydrophilic nanocavity were investigated by means of molecular dynamics simulations. Unlike what is observed in the bulk phase, three dielectric regimes were evidenced, namely an anomalous increase in the dielectric permittivity at low concentrations (with respect to confined pure water), a dielectric plateau at intermediate concentrations and finally a bulk-like behavior for salt concentrations higher than a critical value. It was shown that this peculiar behavior results from the competition between dielectric saturation due to the electric field generated by ions (which tends to lower the dielectric permittivity) and the ion-induced perturbation of pre-oriented water molecules inside the nanocavity which gain some rotational degrees of freedom (entropic contribution) leading to an increase in dipolar fluctuations responsible for the increase in the dielectric permittivity.

  19. Theoretical analysis of aqueous solutions of mixed strong electrolytes by a smaller-ion shell electrostatic model

    NASA Astrophysics Data System (ADS)

    Fraenkel, Dan

    2014-02-01

    In spite of the great importance of mixed electrolytes in science and technology, no compelling theoretical explanation has been offered yet for the thermodynamic behavior of such systems, such as their deviation from ideality and the variation of their excess functions with ionic composition and concentration. Using the newly introduced Smaller-ion Shell treatment - an extension of the Debye-Hückel theory to ions of dissimilar size (hence DH-SiS) - simple analytic mathematical expressions can be derived for the mean and single-ion activity coefficients of binary electrolyte components of ternary ionic systems. Such expressions are based on modifying the parallel DH-SiS equations for pure binary ionic systems, by adding to the three ion-size parameters - a (of counterions), b+ (of positive coions), and b- (of negative coions) - a fourth parameter. For the (+ + -) system, this is "b++," the contact distance between non-coion cations. b++ is derived from fits with experiment and, like the other b's, is constant at varying ion concentration and combination. Four case studies are presented: (1) HCl-NaCl-H2O, (2) HCl-NH4Cl-H2O, (3) (0.01 M HX)-MX-H2O with X = Cl, Br, and with M = Li, Na, K, Cs, and (4) HCl-MCln-H2O with n = 2, M = Sr, Ba; and n = 3, M = Al, Ce. In all cases, theory is fully consistent with experiment when using a of the measured binary electrolyte as the sole fitting parameter. DH-SiS is thus shown to explain known "mysteries" in the behavior of ternary electrolytes, including Harned rule, and to adequately predict the pH of acid solutions in which ionized salts are present at different concentrations.

  20. Theoretical analysis of aqueous solutions of mixed strong electrolytes by a smaller-ion shell electrostatic model

    SciTech Connect

    Fraenkel, Dan

    2014-02-07

    In spite of the great importance of mixed electrolytes in science and technology, no compelling theoretical explanation has been offered yet for the thermodynamic behavior of such systems, such as their deviation from ideality and the variation of their excess functions with ionic composition and concentration. Using the newly introduced Smaller-ion Shell treatment – an extension of the Debye–Hückel theory to ions of dissimilar size (hence DH–SiS) – simple analytic mathematical expressions can be derived for the mean and single-ion activity coefficients of binary electrolyte components of ternary ionic systems. Such expressions are based on modifying the parallel DH–SiS equations for pure binary ionic systems, by adding to the three ion-size parameters – a (of counterions), b{sub +} (of positive coions), and b{sub −} (of negative coions) – a fourth parameter. For the (+ + −) system, this is “b{sub ++},” the contact distance between non-coion cations. b{sub ++} is derived from fits with experiment and, like the other b’s, is constant at varying ion concentration and combination. Four case studies are presented: (1) HCl–NaCl–H{sub 2}O, (2) HCl–NH{sub 4}Cl–H{sub 2}O, (3) (0.01 M HX)–MX–H{sub 2}O with X = Cl, Br, and with M = Li, Na, K, Cs, and (4) HCl–MCl{sub n}–H{sub 2}O with n = 2, M = Sr, Ba; and n = 3, M = Al, Ce. In all cases, theory is fully consistent with experiment when using a of the measured binary electrolyte as the sole fitting parameter. DH–SiS is thus shown to explain known “mysteries” in the behavior of ternary electrolytes, including Harned rule, and to adequately predict the pH of acid solutions in which ionized salts are present at different concentrations.

  1. Tin Coatings Electrodeposited from Sulfonic Acid-Based Electrolytes: Tribological Behavior

    NASA Astrophysics Data System (ADS)

    Bengoa, L. N.; Tuckart, W. R.; Zabala, N.; Prieto, G.; Egli, W. A.

    2015-06-01

    A high efficiency methane sulfonic acid electrolyte used for tin electrodeposition was studied, and the properties of the resulting deposits were compared to those of tin coatings obtained from an industrial phenol sulfonic acid electrolyte. Cyclic voltammetry was used to study the effect of organic additives on the reduction process to define the composition of the electrolytic bath. Thick tin electrodeposits were obtained on rotating cylinder steel electrodes, and their surface morphology, preferred crystal orientation, surface roughness, micro hardness, and tribological behavior were measured. Smooth, adherent, and bright tin coatings were obtained from the methane sulfonic acid electrolyte, which differed in morphology and texture from tin electrodeposited from the industrial bath. Influence of organic additives on preferred crystal orientation of the coatings was found to be stronger than changing the supporting sulfonic acid type. Tribological tests showed that the two types of deposits have a similar coefficient of friction. However, tin coatings obtained from methane sulfonic electrolytes presented a lower wear resistance and underwent galling at lower loads.

  2. Acid-base and electrolyte abnormalities during renal support for acute kidney injury: recognition and management.

    PubMed

    Claure-Del Granado, Rolando; Claure, Rolando; Bouchard, Josée

    2012-01-01

    Acute kidney injury (AKI) is associated with electrolyte and acid-base disturbances such as hyperkalemia, metabolic acidosis, hypocalcemia and hyperphosphatemia. The initiation of dialysis in AKI can efficiently treat these complications. The choice of dialysis modality can be made based on their operational characteristics to tailor the therapy according to the clinical scenario. Each dialysis modality can also trigger significant electrolyte and acid-base disorders, such as hypokalemia, hypophosphatemia and metabolic alkalosis, which may direct changes in fluid delivery and composition. Continuous techniques may be particularly useful in these situations as they allow more time for correction and to maintain balance. This review provides an overview of the electrolyte and acid-base disturbances occurring in AKI and after the initiation of dialysis and discusses therapeutic options in this setting. PMID:23095419

  3. Dependence of the dielectric constant of electrolyte solutions on ionic concentration: A microfield approach

    NASA Astrophysics Data System (ADS)

    Gavish, Nir; Promislow, Keith

    2016-07-01

    We present a microfield approach for studying the dependence of the orientational polarization of the water in aqueous electrolyte solutions upon the salt concentration and temperature. The model takes into account the orientation of the solvent dipoles due to the electric field created by ions, and the effect of thermal fluctuations. The model predicts a dielectric functional dependence of the form ɛ (c ) =ɛw-β L (3 α c /β ) ,β =ɛw-ɛms , where L is the Langevin function, c is the salt concentration, ɛw is the dielectric of pure water, ɛms is the dielectric of the electrolyte solution at the molten salt limit, and α is the total excess polarization of the ions. The functional form gives a remarkably accurate description of the dielectric constant for a variety of salts and a wide range of concentrations.

  4. Dependence of the dielectric constant of electrolyte solutions on ionic concentration: A microfield approach.

    PubMed

    Gavish, Nir; Promislow, Keith

    2016-07-01

    We present a microfield approach for studying the dependence of the orientational polarization of the water in aqueous electrolyte solutions upon the salt concentration and temperature. The model takes into account the orientation of the solvent dipoles due to the electric field created by ions, and the effect of thermal fluctuations. The model predicts a dielectric functional dependence of the form ɛ(c)=ɛ_{w}-βL(3αc/β),β=ɛ_{w}-ɛ_{ms}, where L is the Langevin function, c is the salt concentration, ɛ_{w} is the dielectric of pure water, ɛ_{ms} is the dielectric of the electrolyte solution at the molten salt limit, and α is the total excess polarization of the ions. The functional form gives a remarkably accurate description of the dielectric constant for a variety of salts and a wide range of concentrations. PMID:27575183

  5. Electrochemical etching of a shape memory alloy using new electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Mineta, Takashi

    2004-01-01

    In this paper we present the electrochemical etching characteristics of a shape memory alloy (SMA) using new electrolytes of inorganic salt in alcohol, in comparison with conventional H2SO4-methanol solution. It has become apparent that pattern etching of SMA sheets can be carried out in electrolyte solutions using LiCl and NH4Cl. Especially, in the case of 1 mol l-1 LiCl-ethanol, good etching properties such as a controllable low etch rate of about 3.5 µm min-1, high etch factor (etching depth/side etching width) of 1.5, uniform etching depth and smooth etched surface can be obtained. Throughout etching can be carried out by using a back-side dummy metal of Ni or Cu. This etching technique has been applied to the micromachining of SMA sheet for fabrication of microactuators.

  6. Excited state intramolecular charge transfer reaction in nonaqueous electrolyte solutions: Temperature dependence

    SciTech Connect

    Pradhan, Tuhin; Gazi, Harun Al Rasid; Biswas, Ranjit

    2009-08-07

    Temperature dependence of the excited state intramolecular charge transfer reaction of 4-(1-azetidinyl)benzonitrile (P4C) in ethyl acetate (EA), acetonitrile (ACN), and ethanol at several concentrations of lithium perchlorate (LiClO{sub 4}) has been investigated by using the steady state and time resolved fluorescence spectroscopic techniques. The temperature range considered is 267-343 K. The temperature dependent spectral peak shifts and reaction driving force (-{Delta}G{sub r}) in electrolyte solutions of these solvents can be explained qualitatively in terms of interaction between the reactant molecule and ion-atmosphere. Time resolved studies indicate that the decay kinetics of P4C is biexponential, regardless of solvents, LiClO{sub 4} concentrations, and temperatures considered. Except at higher electrolyte concentrations in EA, reaction rates in solutions follow the Arrhenius-type temperature dependence where the estimated activation energy exhibits substantial electrolyte concentration dependence. The average of the experimentally measured activation energies in these three neat solvents is found to be in very good agreement with the predicted value based on data in room temperature solvents. While the rate constant in EA shows a electrolyte concentration induced parabolic dependence on reaction driving force (-{Delta}G{sub r}), the former in ethanol and ACN increases only linearly with the increase in driving force (-{Delta}G{sub r}). The data presented here also indicate that the step-wise increase in solvent reorganization energy via sequential addition of electrolyte induces the ICT reaction in weakly polar solvents to crossover from the Marcus inverted region to the normal region.

  7. Ionic liquids, electrolyte solutions including the ionic liquids, and energy storage devices including the ionic liquids

    SciTech Connect

    Gering, Kevin L.; Harrup, Mason K.; Rollins, Harry W.

    2015-12-08

    An ionic liquid including a phosphazene compound that has a plurality of phosphorus-nitrogen units and at least one pendant group bonded to each phosphorus atom of the plurality of phosphorus-nitrogen units. One pendant group of the at least one pendant group comprises a positively charged pendant group. Additional embodiments of ionic liquids are disclosed, as are electrolyte solutions and energy storage devices including the embodiments of the ionic liquid.

  8. Polar-solvation classical density-functional theory for electrolyte aqueous solutions near a wall

    NASA Astrophysics Data System (ADS)

    Warshavsky, Vadim; Marucho, Marcelo

    2016-04-01

    A precise description of the structural and dielectric properties of liquid water is critical to understanding the physicochemical properties of solutes in electrolyte solutions. In this article, a mixture of ionic and dipolar hard spheres is considered to account for water crowding and polarization effects on ionic electrical double layers near a uniformly charged hard wall. As a unique feature, solvent hard spheres carrying a dipole at their centers were used to model water molecules at experimentally known concentration, molecule size, and dipolar moment. The equilibrium ionic and dipole density profiles of this electrolyte aqueous model were calculated using a polar-solvation classical density-functional theory (PSCDFT). These profiles were used to calculate the charge density distribution, water polarization, dielectric permittivity function, and mean electric potential profiles as well as differential capacitance, excess adsorptions, and wall-fluid surface tension. These results were compared with those corresponding to the pure dipolar model and unpolar primitive solvent model of electrolyte aqueous solutions to understand the role that water crowding and polarization effects play on the structural and thermodynamic properties of these systems. Overall, PSCDFT predictions are in agreement with available experimental data.

  9. Strong electrolyte continuum theory solution for equilibrium profiles, diffusion limitation, and conductance in charged ion channels.

    PubMed Central

    Levitt, D G

    1985-01-01

    The solution for the ion flux through a membrane channel that incorporates the electrolyte nature of the aqueous solution is a difficult theoretical problem that, until now, has not been properly formulated. The difficulty arises from the complicated electrostatic problem presented by a high dielectric aqueous channel piercing a low dielectric lipid membrane. The problem is greatly simplified by assuming that the ratio of the dielectric constant of the water to that of the lipid is infinite. It is shown that this is a good approximation for most channels of biological interest. This assumption allows one to derive simple analytical expressions for the Born image potential and the potential from a fixed charge in the channel, and it leads to a differential equation for the potential from the background electrolyte. This leads to a rigorous solution for the ion flux or the equilibrium potential based on a combination of the Nernst-Planck equation and strong electrolyte theory (i.e., Gouy-Chapman or Debye-Huckel). This approach is illustrated by solving the system of equations for the specific case of a large channel containing fixed negative charges. The following characteristics of this channels are discussed: anion and mono- and divalent cation conductance, saturation of current with increasing concentration, current-voltage relationship, influence of location and valence of fixed charge, and interaction between ions. The qualitative behavior of this channel is similar to that of the acetylcholine receptor channel. PMID:2410048

  10. Nuclear Magnetic Resonance Studies on Vanadium(IV) Electrolyte Solutions for Vanadium Redox Flow Battery

    SciTech Connect

    Vijayakumar, M.; Burton, Sarah D.; Huang, Cheng; Li, Liyu; Yang, Zhenguo; Graff, Gordon L.; Liu, Jun; Hu, Jian Z.; Skyllas-Kazacos, Maria

    2010-11-15

    The vanadium (IV) electrolyte solutions with various vanadium concentrations are studied by variable temperature 1H and 17O Nuclear Magnetic Resonance (NMR) spectroscopy. The structure and kinetics of vanadium (IV) species in the electrolyte solutions are explored with respect to vanadium concentration and temperature. It was found that the vanadium (IV) species exist as hydrated vanadyl ion, i.e. [VO(H2O)5]2+ forming an octahedral coordination with vanadyl oxygen in the axial position and the remaining positions occupied by water molecules. This hydrated vanadyl ion structure is stable in vanadium concentrations up to 3M and in the temperature range of 240 to 340 K. The sulfate anions in the electrolyte solutions are found to be weekly bound to this hydrated vanadyl ion and occupies its second coordination sphere. The possible effects of these sulfate anions in proton and water exchange between vanadyl ion and solvent molecules are discussed based on 1H and 17O NMR results.

  11. Implementation of equilibrium aqueous speciation and solubility (EQ3 type) calculations into Cantera for electrolyte solutions.

    SciTech Connect

    Moffat, Harry K.; Jove-Colon, Carlos F.

    2009-06-01

    In this report, we summarize our work on developing a production level capability for modeling brine thermodynamic properties using the open-source code Cantera. This implementation into Cantera allows for the application of chemical thermodynamics to describe the interactions between a solid and an electrolyte solution at chemical equilibrium. The formulations to evaluate the thermodynamic properties of electrolytes are based on Pitzer's model to calculate molality-based activity coefficients using a real equation-of-state (EoS) for water. In addition, the thermodynamic properties of solutes at elevated temperature and pressures are computed using the revised Helgeson-Kirkham-Flowers (HKF) EoS for ionic and neutral aqueous species. The thermodynamic data parameters for the Pitzer formulation and HKF EoS are from the thermodynamic database compilation developed for the Yucca Mountain Project (YMP) used with the computer code EQ3/6. We describe the adopted equations and their implementation within Cantera and also provide several validated examples relevant to the calculations of extensive properties of electrolyte solutions.

  12. Polar-solvation classical density-functional theory for electrolyte aqueous solutions near a wall.

    PubMed

    Warshavsky, Vadim; Marucho, Marcelo

    2016-04-01

    A precise description of the structural and dielectric properties of liquid water is critical to understanding the physicochemical properties of solutes in electrolyte solutions. In this article, a mixture of ionic and dipolar hard spheres is considered to account for water crowding and polarization effects on ionic electrical double layers near a uniformly charged hard wall. As a unique feature, solvent hard spheres carrying a dipole at their centers were used to model water molecules at experimentally known concentration, molecule size, and dipolar moment. The equilibrium ionic and dipole density profiles of this electrolyte aqueous model were calculated using a polar-solvation classical density-functional theory (PSCDFT). These profiles were used to calculate the charge density distribution, water polarization, dielectric permittivity function, and mean electric potential profiles as well as differential capacitance, excess adsorptions, and wall-fluid surface tension. These results were compared with those corresponding to the pure dipolar model and unpolar primitive solvent model of electrolyte aqueous solutions to understand the role that water crowding and polarization effects play on the structural and thermodynamic properties of these systems. Overall, PSCDFT predictions are in agreement with available experimental data. PMID:27176352

  13. Design of an efficient electrolyte circulation system for the lead-acid battery

    SciTech Connect

    Thuerk, D.

    1982-01-01

    Application of lead-acid batteries to electric vehicle and other repetitive deep-cycle services produces a non-desirable state in the battery cells, electrolyte stratification. This stratification is the result of acid and water generation at the electrodes during cycling. Water, which is generated during discharge, rises to the electrolyte surface due to gravity differences, whereas the concentrated sulfuric acid generated during charge falls to the bottom of the container. With continued cycling, the extent of the stratification increases and prevents complete charging with low percentages of overcharge. Ultimately this results in extremely short life for the battery system. The industry presently overcomes the stratification problem by substantially overcharging the battery. This abusive overcharge produces gassing rates sufficient to mix the electrolyte during the end portion of the charge. The amount of recharge typically used to mix the electrolyte ranges from 120% to 140% of the prior discharge. Overcharge, even though it is required to eliminate stratification, produces the undesirable results related to high voltage and gassing rates. The design and operation of an electrolyte circulation system are described. (WHK)

  14. AFM forces between mica and polystyrene surfaces in aqueous electrolyte solutions with and without gas bubbles.

    PubMed

    Saavedra, Jorge H; Acuña, Sergio M; Toledo, Pedro G

    2013-11-15

    Force curves between a flat mica substrate and a polystyrene microsphere were measured with an atomic force microscope (AFM) in carefully degassed water and aqueous NaCl, CaCl2, and AlCl3 solutions. The pH of the water used does not change significantly with degassing treatment, and its value remains close to 6. Electrolyte concentration ranges from 10-4 to 10-2M and pH from 4.7 to 5.1. We have found that the repulsive long-range electrostatic force between mica and polystyrene is attenuated by the presence of electrolytes and counterbalanced by a long-range attractive force, which we referred to as a hydrophobic force, which is longer-ranged than the ever present attractive van der Waals force. This force, which includes the adhesive bridging of residual air bubbles and newborn vapor cavities, and any other unknown forces, is reasonably well represented by a unique exponential law. Prefactor and decaying length are not very sensitive to electrolyte type, concentration, and pH, suggesting that any new force included in the law, in addition to adhesive bridges, should obey a non-classical electrostatic mechanism. However, we also know that liquid/solid contact angle and liquid/vapor surface tension increase with electrolyte concentration and valence increasing the stability of bubbles and cavities which in turn increase the bridging force. Clearly, these effects are hidden in the empirical force law. PMID:23998373

  15. Characteristics of tantalum electrolytic capacitors using soluble polypyrrole electrolyte

    NASA Astrophysics Data System (ADS)

    Jang, Kwan Sik; Moon, Bongjin; Oh, Eung Ju; Lee, Hoosung

    Polypyrrole (Ppy) electrolyte solutions in various organic solvents (dimethylformamide, DMF; N-methyl-2-pyrrolidone, NMP; chloroform; trifluoroacetic acid) were prepared using Ppy powder doped with di(2-ethylhexyl)sulfosuccinate sodium salt (Ppy-DEHS) and butylnaphthalene sulfonate sodium salt (Ppy-BNS), respectively. Several tantalum electrolytic capacitors were fabricated by dip coating in these solutions and their electrical properties such as capacitance and tan δ were measured. The capacitors prepared with Ppy-DEHS electrolyte in trifluoroacetic acid showed both high capacitance and low tan δ. Usage of a Ppy electrolyte solution containing both surfactant and a coupling agent also resulted in high capacitance and low tan δ. These phenomena were interpreted in terms of electrical conductivity and chemical structure of the electrolyte, and interactions such as hydrogen bonding, radical addition reaction, covalent bonding between the tantalum oxide layer and the solvent.

  16. Aqueous solutions of acidic ionic liquids for enhanced stability of polyoxometalate-carbon supercapacitor electrodes

    NASA Astrophysics Data System (ADS)

    Hu, Chenchen; Zhao, Enbo; Nitta, Naoki; Magasinski, Alexandre; Berdichevsky, Gene; Yushin, Gleb

    2016-09-01

    Nanocomposites based on polyoxometalates (POMs) nanoconfined in microporous carbons have been synthesized and used as electrodes for supercapacitors. The addition of the pseudocapacitance from highly reversible redox reaction of POMs to the electric double-layer capacitance of carbon lead to an increase in specific capacitance of ∼90% at 1 mV s-1. However, high solubility of POM in traditional aqueous electrolytes leads to rapid capacity fading. Here we demonstrate that the use of aqueous solutions of protic ionic liquids (P-IL) as electrolyte instead of aqueous sulfuric acid solutions offers an opportunity to significantly improve POM cycling stability. Virtually no degradation in capacitance was observed in POM-based positive electrode after 10,000 cycles in an asymmetric capacitor with P-IL aqueous electrolyte. As such, POM-based carbon composites may now present a viable solution for enhancing energy density of electrical double layer capacitors (EDLC) based on pure carbon electrodes.

  17. Design of an efficient electrolyte circulation system for the lead-acid battery

    NASA Astrophysics Data System (ADS)

    Thuerk, D.

    The design and operation of an electrolyte circulation system are described. Application of lead acid batteries to electric vehicle and other repetitive deep cycle services produces a nondesirable state in the battery cells, electrolyte stratification. This stratification is the result of acid and water generation at the electrodes during cycling. With continued cycling, the extent of the stratification increases and prevents complete charging with low percentages of overcharge. Ultimately this results in extremely short life for the battery system. The stratification problem was overcome by substantially overcharging the battery. This abusive overcharge produces gassing rates sufficient to mix the electrolyte during the end portion of the charge. Overcharge, even though it is required to eliminate stratification, produces the undesirable results related to high voltage and gassing rates.

  18. Underwater microdischarge in arranged microbubbles produced by electrolysis in electrolyte solution using fabric-type electrode

    SciTech Connect

    Sakai, Osamu; Kimura, Masaru; Tachibana, Kunihide; Shirafuji, Tatsuru

    2008-12-08

    Pulsed microdischarge was generated in microbubbles produced by electrolysis in an electrolyte solution without external gas feed by using a fabric-type electrode. The electrode structure not only allowed low-voltage ignition of the atmospheric-pressure discharge in hydrogen or oxygen containing microbubbles but also worked effectively in producing and holding the bubbles on its surface. The generation of reactive species was verified by optical emissions from the produced microplasmas, and their transport into the solution was monitored by the change in hydrogen concentration.

  19. THE INFLUENCE OF ELECTROLYTES ON THE SOLUTION AND PRECIPITATION OF CASEIN AND GELATIN.

    PubMed

    Loeb, J; Loeb, R F

    1921-11-20

    1. Colloids have been divided into two groups according to the ease with which their solutions or suspensions are precipitated by electrolytes. One group (hydrophilic colloids), e.g., solutions of gelatin or crystalline egg albumin in water, requires high concentrations of electrolytes for this purpose, while the other group (hydrophobic colloids) requires low concentrations. In the latter group the precipitating ion of the salt has the opposite sign of charge as the colloidal particle (Hardy's rule), while no such relation exists in the precipitation of colloids of the first group. 2. The influence of electrolytes on the solubility of solid Na caseinate, which belongs to the first group (hydrophilic colloids), and of solid casein chloride which belongs to the second group (hydrophobic colloids), was investigated and it was found that the forces determining the solution are entirely different in the two cases. The forces which cause the hydrophobic casein chloride to go into solution are forces regulated by the Donnan equilibrium; namely, the swelling of particles. As soon as the swelling of a solid particle of casein chloride exceeds a certain limit it is dissolved. The forces which cause the hydrophilic Na caseinate to go into solution are of a different character and may be those of residual valency. Swelling plays no rôle in this case, and the solubility of Na caseinate is not regulated by the Donnan equilibrium. 3. The stability of solutions of casein chloride (requiring low concentrations of electrolytes for precipitation) is due, first, to the osmotic pressure generated through the Donnan equilibrium between the casein ions tending to form an aggregate, whereby the protein ions of the nascent micellum are forced apart again; and second, to the potential difference between the surface of a micellum and the surrounding solution (also regulated by the Donnan equilibrium) which prevents the further coalescence of micella already formed. This latter consequence

  20. The effect of different kinds of electrolyte and non-electrolyte solutions on the survival rate and morphology of zebrafish Danio rerio embryos.

    PubMed

    Lahnsteiner, F

    2009-11-01

    The effect of electrolyte and non-electrolyte solutions on the survival and on the morphology of zebrafish Danio rerio embryos was investigated. Embryos in different ontogenetic stages were incubated in electrolyte (NaCl, KCl, MgCl2 and CaCl2) and non-electrolyte solutions [sucrose and polyvinylalcohol (PVA)] of different concentrations for 5-15 min. The embryos were hatched to the long-pec stage and the effective concentrations which caused a 50% decrease in embryo development (EC50) were determined. The morphometric changes, which were caused by the test solutions, were measured. Ion channel blockers were used to see if active ion transport played a role for embryo survival. Finally, dechorionated embryos were exposed to the test solutions to get indications about the importance of chorion and perivitelline space. For 12 hours post fertilization (hpf) embryos and a 15 min exposure period, EC50 was highest for MgCl2 (1.60 mol l(-1)), followed by sucrose (0.73 mol l(-1)), NaCl (0.49 mol l(-1)), KCl (0.44 mol l(-1)), CaCl2 (0.43 mol l(-1)) and PVA [0.0005 mol l(-1) (2.2%)]. EC50 were lower for early embryonic stages than for advanced stages for all solutions with exception of MgCl2 and sucrose. At the EC50, MgCl2 and CaCl2 solutions did not induce morphometric changes. NaCl and sucrose solutions induced reversible morphometric changes, which were compensated within 10 min. Only the EC50 of KCl and PVA solutions induced permanent morphometric changes, which could not be compensated. Incubation of embryos in electrolyte and non-electrolyte solutions together with ouabain (blocker of Na+- K+ ATPase), HgCl3 (dose-dependent inhibition of aquaporine channels), verapamil (inhibition of calcium and magnesium uptake) and amiloride (inhibition of sodium uptake) significantly decreased the per cent of embryos developing to the long-pec stage in comparison to the same solutions without blockers. Ouabain and HgCl(3) also induced morphometric changes. For dechorionated embryos

  1. The effect of acidity of electrolyte on the porosity and the nanostructure morphology of electrolytic manganese dioxide

    NASA Astrophysics Data System (ADS)

    Adelkhani, H.

    2012-06-01

    The effects of acidity of electrolyte (pH) on the hysteresis behavior, the specific surface area, and nanostructure morphology of electrolytic manganese dioxides (EMDs) have been studied by using the Barrett-Joyner-Halenda (BJH) analysis, X-ray diffraction (XRD) and scanning electron microscopy (SEM) images analysis. EMD samples are electrodeposited at a variable pH (6 to 1) and many fixed pH (2, 3, 4, 5, and 6). Results indicate that pH play key roles in the characteristics of EMD. The samples obtained at low pH (2 and 3) show multi-branched morphology and represent a H4 hysteresis loop. At pH 4 and 5, a uniform and dense structure of MnO2 is obtained without hysteresis behavior. The sample electrodeposited at pH 6 shows a regular reticulate, that its adsorption-desorption isotherm show hysteresis behavior. By electrodeposition at a variable pH, the sample shows a cauliflower-like and multi-branched form. From the viewpoint of classification of isotherm, pH strongly affects on Type of isotherm. The results show that γ-MnO2 is as main-product of electrodeposition and α-MnO2 and β-MnO2 were obtained as side-product at low and high pH, respectively.

  2. Influence of ionic strength on poly(diallyldimethylammonium chloride) macromolecule conformations in electrolyte solutions.

    PubMed

    Adamczyk, Zbigniew; Jamroży, Krzysztof; Batys, Piotr; Michna, Aneta

    2014-12-01

    Conformations of poly(diallyldimethylammonium chloride), PDADMAC, molecules in electrolyte solutions were experimentally evaluated by dynamic light scattering (DLS), micro-electrophoretic and viscosity measurements. The role of ionic strength varied within 10(-4) and 2M was systematically studied. The diffusion coefficient of the polymer molecules was equal to 1.3×10(-7)cm(2)s(-1) for the ionic strength range 5×10(-4) to 10(-2)M decreasing slightly for higher ionic strength. This corresponds to the hydrodynamic diameter of 38.5nm. Using the diffusion coefficient and the electrophoretic mobility data, the electrokinetic charge on PDADMAC molecules was calculated as a function of ionic strength. It was positive and varied between 84 and 51 elementary charges. This gives the effective ionization degree of the macromolecule equal to 13% and 8% for ionic strength of 5×10(-4) and 0.15M, respectively. Additional information about macromolecule conformation was derived from the viscosity measurements of dilute PDADMAC solutions. The intrinsic viscosity derived from these measurements decreased abruptly with ionic strength from 3400 for 10(-4)M to 100 for 2M, NaCl solutions. By extrapolating the hydrodynamic diameter and intrinsic viscosity data to zero ionic strength the polyelectrolyte molecule contour length of 240nm and the backbone diameter of 0.85nm were predicted. On the other hand, the decrease in the intrinsic viscosity for higher ionic strength was attributed to changes in macromolecule conformations to more collapsed ones. The experimental results were interpreted by molecular dynamics modeling of PDADMAC chain conformations in electrolyte solutions where the ionic strength effect and the effective ionization degree were considered. A quantitative agreement was attained for lower ionic strength range proving that the combined DLS and viscosity measurements furnish reliable information about macromolecule conformations in electrolyte solution. PMID:25265546

  3. Studies on zinc nodules electrodeposited from acid electrolytes

    SciTech Connect

    Anderson, R.; Tobias, C.W.

    1984-12-01

    The development of morphology of electrodeposited zinc was investigated by studying the initial stages of deposition. Zinc was deposited galvanostatically from 1.0 M ZnCl/sub 2/ electrolyte (0.7 < pH < 4.6) on rotating disc electrodes at current densities from 5 to 130 ma/cm/sup 2/. Pine glassy carbon, Union Carbide pyrolytic graphite, Gould pyrolytic graphite, Exxon graphite loaded polymer, and platinum substrates were used. The number densities of nodules (diameter greater than 1 ..mu..m), typically encountered during incipient morphological development, were measured using scanning electron microscopy and image analysis. Nodule densities up to 7 x 10/sup 4/ nodules/mm/sup 2/ were measured.

  4. Electrolyte Diets, Stress, and Acid-Base Balance in Broiler Chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this study was to compare acid-base balance in broiler chickens provided diets’ containing two different dietary electrolyte balances (DEB) and administered either adrenocorticotropic hormone (ACTH) or saline. Diets were moderate (M; 174 mEq/kg) or high (H; 241 mEq/kg) DEB by altering Na-...

  5. Kinetics of the Elementary Act of Electrochemical Reactions at the Semiconductor-Electrolyte Solution Interface

    NASA Astrophysics Data System (ADS)

    Kovalenko, Sergii; Soloviev, Veniamin

    2014-12-01

    In the framework of the quantum-mechanical theory of elementary act of non-adiabatic electrochemical reactions, it is carried out the calculation of the discharge current of ions at the semiconductor-electrolyte solution interface using the model of isotropic spherically symmetric band. It is shown that our results generalize the well-known formulae for the current density obtained by Dogonadze, Kuznetsov, and Chizmadzhev [R. R. Dogonadze, A. M. Kuznetsov, and Yu. A. Chizmadzhev, The kinetics of some heterogeneous reactions at semiconductor-electrolyte interface, Zhur. Fiz. Khim. 38, 1195 (1964)]. The average densities of states in the valence band and the conduction band of the semiconductor electrode in the heterogeneous charge transfer are found.

  6. Challenge in manufacturing electrolyte solutions for lithium and lithium ion batteries quality control and minimizing contamination level

    NASA Astrophysics Data System (ADS)

    Heider, U.; Oesten, R.; Jungnitz, M.

    The quality of electrolytes for lithium batteries are a major topic in science and battery industries. The solvents and lithium salts should be of highest purity. Therefore, during preparation and handling of electrolyte solutions, the contamination level has to be minimized and the quality during packaging, storage and transportation has to be guaranteed. Especially, protic impurities are found to be very critical for LiPF 6-based electrolytes. The influence of water is reported to be tremendous. But also other protic impurities like alcohols are considered to play an important role in the electrolyte quality. The reaction of the protic impurities with LiPF 6 leads to the formation of HF which further reacts with cathode active materials (e.g., spinel) and the passivating films of the cathode and anode. For a better understanding of the protic impurities and their role in the electrolyte quality a systematic investigation of different impurities was carried out. Electrolytes were doped with different protic compounds. Then the electrolyte was analyzed for protic impurities and HF in dependence of time. First results showing the relation between protic impurities and HF are presented and discussed. In addition, different packaging materials for the electrolyte solutions were investigated. Storage tests were carried out at different temperatures and in different atmospheres. Results on contamination levels, influence of packaging, high temperature storage and handling are addressed.

  7. An amino acid-electrolyte beverage may increase cellular rehydration relative to carbohydrate-electrolyte and flavored water beverages

    PubMed Central

    2014-01-01

    Background In cases of dehydration exceeding a 2% loss of body weight, athletic performance can be significantly compromised. Carbohydrate and/or electrolyte containing beverages have been effective for rehydration and recovery of performance, yet amino acid containing beverages remain unexamined. Therefore, the purpose of this study is to compare the rehydration capabilities of an electrolyte-carbohydrate (EC), electrolyte-branched chain amino acid (EA), and flavored water (FW) beverages. Methods Twenty men (n = 10; 26.7 ± 4.8 years; 174.3 ± 6.4 cm; 74.2 ± 10.9 kg) and women (n = 10; 27.1 ± 4.7 years; 175.3 ± 7.9 cm; 71.0 ± 6.5 kg) participated in this crossover study. For each trial, subjects were dehydrated, provided one of three random beverages, and monitored for the following three hours. Measurements were collected prior to and immediately after dehydration and 4 hours after dehydration (3 hours after rehydration) (AE = −2.5 ± 0.55%; CE = −2.2 ± 0.43%; FW = −2.5 ± 0.62%). Measurements collected at each time point were urine volume, urine specific gravity, drink volume, and fluid retention. Results No significant differences (p > 0.05) existed between beverages for urine volume, drink volume, or fluid retention for any time-point. Treatment x time interactions existed for urine specific gravity (USG) (p < 0.05). Post hoc analysis revealed differences occurred between the FW and EA beverages (p = 0.003) and between the EC and EA beverages (p = 0.007) at 4 hours after rehydration. Wherein, EA USG returned to baseline at 4 hours post-dehydration (mean difference from pre to 4 hours post-dehydration = -0.0002; p > 0.05) while both EC (-0.0067) and FW (-0.0051) continued to produce dilute urine and failed to return to baseline at the same time-point (p < 0.05). Conclusion Because no differences existed for fluid retention, urine or drink volume at any time point, yet USG returned to

  8. Solvent activity in electrolyte solutions from molecular simulation of the osmotic pressure

    NASA Astrophysics Data System (ADS)

    Kohns, Maximilian; Reiser, Steffen; Horsch, Martin; Hasse, Hans

    2016-02-01

    A method for determining the activity of the solvent in electrolyte solutions by molecular dynamics simulations is presented. The electrolyte solution is simulated in contact with the pure solvent. Between the two phases, there is a virtual membrane, which is permeable only for the solvent. In the simulation, this is realized by an external field which acts only on the solutes and confines them to a part of the simulation volume. The osmotic pressure, i.e., the pressure difference between both phases, is obtained with high accuracy from the force on the membrane, so that reliable data on the solvent activity can be determined. The acronym of the new method is therefore OPAS (osmotic pressure for activity of solvents). The OPAS method is verified using tests of varying complexity. This includes a comparison of results from the OPAS method for aqueous NaCl solutions to results from the literature which were obtained with other molecular simulation methods. Favorable agreement is observed not only for the solvent activity but also for the activity coefficient of NaCl, which is obtained by application of the Gibbs-Duhem equation.

  9. Solvent activity in electrolyte solutions from molecular simulation of the osmotic pressure.

    PubMed

    Kohns, Maximilian; Reiser, Steffen; Horsch, Martin; Hasse, Hans

    2016-02-28

    A method for determining the activity of the solvent in electrolyte solutions by molecular dynamics simulations is presented. The electrolyte solution is simulated in contact with the pure solvent. Between the two phases, there is a virtual membrane, which is permeable only for the solvent. In the simulation, this is realized by an external field which acts only on the solutes and confines them to a part of the simulation volume. The osmotic pressure, i.e., the pressure difference between both phases, is obtained with high accuracy from the force on the membrane, so that reliable data on the solvent activity can be determined. The acronym of the new method is therefore OPAS (osmotic pressure for activity of solvents). The OPAS method is verified using tests of varying complexity. This includes a comparison of results from the OPAS method for aqueous NaCl solutions to results from the literature which were obtained with other molecular simulation methods. Favorable agreement is observed not only for the solvent activity but also for the activity coefficient of NaCl, which is obtained by application of the Gibbs-Duhem equation. PMID:26931686

  10. Onsager’s reciprocal relations in electrolyte solutions. I. Sedimentation and electroacoustics

    SciTech Connect

    Gourdin-Bertin, S.; Bernard, O.; Jardat, M.; Chassagne, C.

    2015-08-14

    In the framework of irreversible thermodynamics, we show that the sedimentation current in electrolyte solutions is mathematically equivalent to the low frequency limit of the ionic vibration current, appearing in the presence of an acoustic wave. This non-trivial result is obtained thanks to a careful choice of the reference frame used to express the mass fluxes in the context of electroacoustics. Coupled transport phenomena in electrolyte solutions can also be investigated in a mechanical framework, with a set of Newtonian equations for the dynamics of charged solutes. Both in the context of sedimentation and of electroacoustics, we show that the results obtained in the mechanical framework, in the ideal case (i.e., without interactions between ions), do satisfy the Onsager’s reciprocal relations. We also derive the general relation between corrective forces accounting for ionic interactions which must be fulfilled so that the Onsager’s reciprocal relations are verified. Finally, we show that no additional diffusion term needs to be taken into account in the flux of solutes (far from the walls), even if local concentration gradients exist, contrarily to what was done previously in the literature.

  11. Compatibility of electrolytically produced sodium hypochlorite solutions on long- term implanted dialysis catheters.

    PubMed

    Mishkin, G J

    2007-01-01

    More than 20% of the world's population use a catheter for dialysis, despite guidelines limiting their use. Although the structure and design of the catheters differ by manufacturer, the material used in central venous catheters and peritoneal dialysis catheters are the same across manufacturers. Given the long-term use of these catheters in the dialysis population, the good compatibility of the antiseptics and disinfectants used on the catheters is imperative to prevent failure and cracking of the catheter material. Tensile strengths of commercially available catheters were measured after exposure to commonly used disinfectants. The tensile strength was then compared between the catheters by analyzing the displacement vs. force (N) curves produced during the evaluation. A total of 44 catheter lumens were evaluated. The electrolytically produced sodium hypochlorite solution, Alcavis 50/ExSept Plus, was the only solution shown to be compatible with all three catheter materials resulting in a deviation of less than 10% for each of the different catheter types. Electrolytically produced sodium hypochlorite solutions were the only solutions in this study that did not alter the physical properties of any of the catheters after long-term exposure. PMID:17099302

  12. Electrogenerated chemiluminescence induced by sequential hot electron and hole injection into aqueous electrolyte solution.

    PubMed

    Salminen, Kalle; Kuosmanen, Päivi; Pusa, Matti; Kulmala, Oskari; Håkansson, Markus; Kulmala, Sakari

    2016-03-17

    Hole injection into aqueous electrolyte solution is proposed to occur when oxide-coated aluminum electrode is anodically pulse-polarized by a voltage pulse train containing sufficiently high-voltage anodic pulses. The effects of anodic pulses are studied by using an aromatic Tb(III) chelate as a probe known to produce intensive hot electron-induced electrochemiluminescence (HECL) with plain cathodic pulses and preoxidized electrodes. The presently studied system allows injection of hot electrons and holes successively into aqueous electrolyte solutions and can be utilized in detecting electrochemiluminescent labels in fully aqueous solutions, and actually, the system is suggested to be quite close to a pulse radiolysis system providing hydrated electrons and hydroxyl radicals as the primary radicals in aqueous solution without the problems and hazards of ionizing radiation. The analytical power of the present excitation waveforms are that they allow detection of electrochemiluminescent labels at very low detection limits in bioaffinity assays such as in immunoassays or DNA probe assays. The two important properties of the present waveforms are: (i) they provide in situ oxidation of the electrode surface resulting in the desired oxide film thickness and (ii) they can provide one-electron oxidants for the system by hole injection either via F- and F(+)-center band of the oxide or by direct hole injection to valence band of water at highly anodic pulse amplitudes. PMID:26920769

  13. Degradation of ascorbic acid in ethanolic solutions.

    PubMed

    Hsu, Hsin-Yun; Tsai, Yi-Chin; Fu, Chi-Chang; Wu, James Swi-Bea

    2012-10-24

    Ascorbic acid occurs naturally in many wine-making fruits. The industry also uses ascorbic acid as an antioxidant and color stabilizer in the making of alcoholic beverages including white wine, wine cooler, alcopop, and fruit liqueur. However, the degradation of ascorbic acid itself may cause browning and the deterioration of color quality. This study was aimed to monitor the degradation of ascorbic acid, the formation of degradation products, and the browning in storage of ascorbic acid containing 0-40% (v/v) ethanolic solutions buffered at pH 3.2 as models of alcoholic beverages. The results show that ascorbic acid degradation in the ethanolic solutions during storage follows first-order reaction, that the degradation and browning rates increase with the increase of ethanol concentration, that the activation energy for the degradation of ascorbic acid is in the range 10.35-23.10 (kcal/mol), that 3-hydroxy-2-pyrone is an indicator and a major product of ascorbic acid degradation, and that aerobic degradation pathway dominants over anaerobic pathway in ascorbic acid degradation in ethanolic solutions. PMID:22994409

  14. The anodizing behavior of aluminum in malonic acid solution and morphology of the anodic films

    NASA Astrophysics Data System (ADS)

    Ren, Jianjun; Zuo, Yu

    2012-11-01

    The anodizing behavior of aluminum in malonic acid solution and morphology of the anodic films were studied. The voltage-time response for galvanostatic anodization of aluminum in malonic acid solution exhibits a conventional three-stage feature but the formation voltage is much higher. With the increase of electrolyte concentration, the electrolyte viscosity increases simultaneously and the high viscosity decreases the film growth rate. With the concentration increase of the malonic acid electrolyte, the critical current density that initiates local "burning" on the sample surface decreases. For malonic acid anodization, the field-assisted dissolution on the oxide surface is relatively weak and the nucleation of pores is more difficult, which results in greater barrier layer thickness and larger cell dimension. The embryo of the porous structure of anodic film has been created within the linear region of the first transient stage, and the definite porous structure has been established before the end of the first transient stage. The self-ordering behavior of the porous film is influenced by the electrolyte concentration, film thickness and the applied current density. Great current density not only improves the cell arrangement order but also brings about larger cell dimension.

  15. Considerations on electrical impedance measurements of electrolyte solutions in a four-electrode cell

    NASA Astrophysics Data System (ADS)

    Chaparro, C. V.; Herrera, L. V.; Meléndez, A. M.; Miranda, D. A.

    2016-02-01

    A tetrapolar probe to measure the electrical properties of electrolyte solutions was implemented with gold electrodes according to the van der Pauw method. Electrical impedance spectroscopy (EIS) measurements of different concentrations of phosphate buffer saline (PBS) solution and an oral mucosal tissue sample dispersed in PBS were performed in the galvanostatic mode using a four-electrode cell (tetrapolar probe). Taking advantage of using a potentiostat/galvanostat for carrying out the electrical measurements, a simple and rapid method using a three-electrode electrochemical cell is described for: a) cleaning of electrodes, b) verification of surface chemical state of electrode material and c) choice of current supplied to electrodes for EIS measurements. Results of this research shown a depolarization effect due to the addition of oral mucosa tissue cells into the PBS solution.

  16. Electrical and Optical Studies of Interfaces Between Electrolyte Solutions and Semiconductors or Metals

    NASA Astrophysics Data System (ADS)

    Dollard, William Joseph

    In Part I, experimental studies of the time-resolved bandgap emission of CdSe are used to probe the attributes required in a theoretical model for the carrier dynamics of semiconductor electrodes. The experimental results show that the details of bulk recombination, the effects of self-absorption and the influence of the space charge field are quite important factors for the carrier dynamics. Simulation results show that the detailed kinetics of the interfacial recombination can also have important consequences for the carrier relaxation. Five different silane compounds are used to chemically modify the CdSe interface and change the surface recombination velocity. A general trend of increasing recombination velocity with increasing ionization potential of the silane is observed. In Part II, the desirability of resolving the activities of solutions of electrolytes into the individual ionic contributions is discussed. In this work we follow an approach pioneered by Parsons involving measurement in the jet (Kenrick) cell of outer-potential differences between solutions of the same electrolyte in two solvents. These potential differences provide the "real" free energies of transfer of individual ions which, in turn, differ from the usual Gibbs energies of transfer by the work required to transfer the ion through the dipolar layers at the two solvent-gas interfaces. The new extrathermodynamic assumption is now that the difference between the surface potentials of the two solvents can be estimated. One objective of this work was to improve the reliability of "real" free energy of transfer measurements, which are experimentally demanding, to within ca. 0.5 kJ mol^{ -1} in order to match typical uncertainties in Gibbs transfer energies of electrolytes. This goal was met, in most instances, by careful evaluation of experimental parameters (particularly jet pressure) influencing the measurement of outer-potential differences. A major improvement over previous measurements

  17. Reference electrode for strong oxidizing acid solutions

    DOEpatents

    Rigdon, Lester P.; Harrar, Jackson E.; Bullock, Sr., Jack C.; McGuire, Raymond R.

    1990-01-01

    A reference electrode for the measurement of the oxidation-reduction potentials of solutions is especially suitable for oxidizing solutions such as highly concentrated and fuming nitric acids, the solutions of nitrogen oxides, N.sub.2 O.sub.4 and N.sub.2 O.sub.5, in nitric acids. The reference electrode is fabricated of entirely inert materials, has a half cell of Pt/Ce(IV)/Ce(III)/70 wt. % HNO.sub.3, and includes a double-junction design with an intermediate solution of 70 wt. % HNO.sub.3. The liquid junctions are made from Corning No. 7930 glass for low resistance and negligible solution leakage.

  18. A new electrolyte formulation for low cost cycling lead acid batteries

    NASA Astrophysics Data System (ADS)

    Torcheux, L.; Lailler, P.

    This paper is devoted to the development of a new lead acid battery electrolyte formulation for cycling applications, especially for renewable energy markets in developing countries. These emerging markets, such as solar home systems, require lead acid batteries at very low prices and improved performances compared to automotive batteries produced locally. The new acid formulation developed is a mixture of sulphuric acid, liquid colloidal silica and other additives including phosphoric acid. The colloidal silica is used at a low concentration in order to decrease the acid stratification process during cycling at high depth of discharge. Phosphoric acid is used for the improvement of the textural evolution of the positive active material during cycling. After a description of the markets and of the additives used in the new acid formulation, this paper presents the results obtained with normalised photovoltaic cycle testing on low cost automotive batteries modified by the new electrolyte formulation. It is shown that the cycling life of such batteries is much increased in the presence of the new formulation. These results are explained by the improved evolution of positive active mass softening parameters (specific surface and β-PbO 2 crystallite size) and also by a more homogeneous sulphating process on both plates.

  19. Recovery of mercury from mercury compounds via electrolytic methods

    DOEpatents

    Grossman, M.W.; George, W.A.

    1989-11-07

    A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg[sub 2]Cl[sub 2] employing as the electrolyte solution a mixture of HCl and H[sub 2]O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H[sub 2]O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds. 3 figs.

  20. Recovery of mercury from mercury compounds via electrolytic methods

    DOEpatents

    Grossman, Mark W.; George, William A.

    1989-01-01

    A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg.sub.2 Cl.sub.2 employing as the electrolyte solution a mixture of HCl and H.sub.2 O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H.sub.2 O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds.

  1. Recovery of mercury from mercury compounds via electrolytic methods

    DOEpatents

    Grossman, M.W.; George, W.A.

    1991-06-18

    A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg[sub 2]Cl[sub 2] employing as the electrolyte solution a mixture of HCl and H[sub 2]O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H[sub 2]O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds. 3 figures.

  2. Recovery of mercury from mercury compounds via electrolytic methods

    DOEpatents

    Grossman, Mark W.; George, William A.

    1991-01-01

    A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg.sub.2 Cl.sub.2 employing as the electrolyte solution a mixture of HCl and H.sub.2 O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H.sub.2 O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds.

  3. Recovery of mercury from mercury compounds via electrolytic methods

    DOEpatents

    Grossman, Mark W.; George, William A.

    1988-01-01

    A process for electrolytically recovering mercury from mercury compounds is provided. In one embodiment, Hg is recovered from Hg.sub.2 Cl.sub.2 employing as the electrolyte solution a mixture of HCl and H.sub.2 O. In another embodiment, Hg is electrolytically recovered from HgO wherein the electrolyte solution is comprised of glacial acetic acid and H.sub.2 O. Also provided is an apparatus for producing isotopically enriched mercury compounds in a reactor and then transporting the dissolved compounds into an electrolytic cell where mercury ions are electrolytically reduced and elemental mercury recovered from the mercury compounds.

  4. Effect of fulvic acids on the electrolytes physiology in vertebrates

    NASA Astrophysics Data System (ADS)

    Morales, O. Y.; Navarrete, J. M.; Gracia, I.; Macias, L.; Rivera, M.; Sanchez, F.

    2011-10-01

    Fulvic acids are the active principle in humus fertilizers which are the cause of better absorption of mineral ions from soil to plant tissues. Tested in mice by making use of radioactive labeled ions, they showed their action of enhancing by a factor greater than two the filtration through liver of PO 43- and Ca 2+ from digestive tract to blood serum as well as through kidney from blood serum to urine. Following this research, Fe 3+ and I 1- ions labeled with 59Fe and 131I have been tested and reported in the present paper. Results showed that iron ions are completely fixed in red cells, with no residue eliminated by urine, while iodine ions are fixed in thyroid gland, with some residue eliminated by urine. Both ions were fixed in said tissues by factors larger than two when they are escorted by fulvic acids. A general distribution of these ions in blood, urine, feces, liver, kidney and thyroid gland has been surveyed, trying to find the earliest effect of fulvic acids in the physiology of vertebrates.

  5. Evaluation of tetrafluoroethane-1,2-disulfonic acid as a fuel cell electrolyte

    SciTech Connect

    Ross, P.N. Jr.

    1983-04-01

    Fuel cell cathode polarization in 70 w/o tetrafluoroethane-1,2-disulfonic acid (TFEDSA) was compared with that observed in trifluoromethane sulfonic acid (TFMSA) and phosphoric acid electrolytes. The type of electrode used was a wet-proofed Stackpole carbon paper substrate with the catalyst layer applied by direct filtration. The catalyst was 10 w/o Pt on Vulcan XC-72R carbon black supplied by Prototech and used as received. The polytetrafluoroethylene (PTFE) content and the curing conditions for the cathodes were optimized for each electrolyte by trial and error. The resulting polarization curves were infrarad corrected and show that all three electrolytes have about the same conductivity under the conditions used. The polarization behavior in TFEDSA was intermediate between that for 85 w/o phosphoric acid and that for 60 w/o TFMSA. More quantitative kinetic measurements in concentrated TFEDSA and also TFMSA were attempted using the rotating disc method but electrolyte impurity problems prevented definite determinations. The polarization results and the conductivity data indicate that it should be possible to operate a reformed methanol (0.1% CO) fuel cell using 70% TFEDSA at 110 degrees C and achieve a potential of 0.64V per cell on air at 200 mA/cm/sup 2/ with 0.75 mg Pt/cm/sup 2/ of catalyst. An impurity in TFMSA appears to be the source of sulfur produced at a hydrogen electrode in unpurified acid; the impurity is probably SO/sub 3/. Early samples of TFESDA were badly contaminated with sulfur oxides but improvement in synthesis eliminated these impurities. Purified forms of TFMSA and TFEDSA showed no chemical instability in the fuel cell tests in this laboratory.

  6. Sulfuric acid-methanol electrolytes as an alternative to sulfuric-hydrofluoric acid mixtures for electropolishing of niobium

    SciTech Connect

    Zhao, Xin; Corcoran, Sean G.; Kelley, Michael J.

    2011-06-01

    Attainment of the greatest possible interior surface smoothness is critical to meeting the performance demands placed upon niobium superconducting radiofrequency (SRF) accelerator cavities by next generation projects. Electropolishing with HF-H{sub 2}SO{sub 4} electrolytes yields cavities that meet SRF performance goals, but a less-hazardous, more environmentally-friendly process is desirable. Reported studies of EP on chemically-similar tantalum describe the use of sulfuric acid-methanol electrolytes as an HF-free alternative. Reported here are the results of experiments on niobium samples with this electrolyte. Voltammetry experiments indicate a current plateau whose voltage range expands with increasing acid concentration and decreasing temperature. Impedance spectroscopy indicates that a compact salt film is responsible for the current plateau. Equivalent findings in electropolishing chemically-similar tantalum with this electrolyte were interpreted due to as mass transfer limitation by diffusion of Ta ions away from the anode surface. We infer that a similar mechanism is at work here. Conditions were found that yield leveling and brightening comparable to that obtained with HF-H{sub 2}SO{sub 4} mixtures.

  7. Promoting solution phase discharge in Li-O2 batteries containing weakly solvating electrolyte solutions.

    PubMed

    Gao, Xiangwen; Chen, Yuhui; Johnson, Lee; Bruce, Peter G

    2016-08-01

    On discharge, the Li-O2 battery can form a Li2O2 film on the cathode surface, leading to low capacities, low rates and early cell death, or it can form Li2O2 particles in solution, leading to high capacities at relatively high rates and avoiding early cell death. Achieving discharge in solution is important and may be encouraged by the use of high donor or acceptor number solvents or salts that dissolve the LiO2 intermediate involved in the formation of Li2O2. However, the characteristics that make high donor or acceptor number solvents good (for example, high polarity) result in them being unstable towards LiO2 or Li2O2. Here we demonstrate that introduction of the additive 2,5-di-tert-butyl-1,4-benzoquinone (DBBQ) promotes solution phase formation of Li2O2 in low-polarity and weakly solvating electrolyte solutions. Importantly, it does so while simultaneously suppressing direct reduction to Li2O2 on the cathode surface, which would otherwise lead to Li2O2 film growth and premature cell death. It also halves the overpotential during discharge, increases the capacity 80- to 100-fold and enables rates >1 mA cmareal(-2) for cathodes with capacities of >4 mAh cmareal(-2). The DBBQ additive operates by a new mechanism that avoids the reactive LiO2 intermediate in solution. PMID:27111413

  8. Three-phase contact line and line tension of electrolyte solutions in contact with charged substrates

    NASA Astrophysics Data System (ADS)

    Ibagon, Ingrid; Bier, Markus; Dietrich, S.

    2016-06-01

    The three-phase contact line formed by the intersection of a liquid–vapor interface of an electrolyte solution with a charged planar substrate is studied in terms of classical density functional theory applied to a lattice model. The influence of the substrate charge density and of the ionic strength of the solution on the intrinsic structure of the three-phase contact line and on the corresponding line tension is analyzed. We find a negative line tension for all values of the surface charge density and of the ionic strength considered. The strength of the line tension decreases upon decreasing the contact angle via varying either the temperature or the substrate charge density.

  9. Three-phase contact line and line tension of electrolyte solutions in contact with charged substrates.

    PubMed

    Ibagon, Ingrid; Bier, Markus; Dietrich, S

    2016-06-22

    The three-phase contact line formed by the intersection of a liquid-vapor interface of an electrolyte solution with a charged planar substrate is studied in terms of classical density functional theory applied to a lattice model. The influence of the substrate charge density and of the ionic strength of the solution on the intrinsic structure of the three-phase contact line and on the corresponding line tension is analyzed. We find a negative line tension for all values of the surface charge density and of the ionic strength considered. The strength of the line tension decreases upon decreasing the contact angle via varying either the temperature or the substrate charge density. PMID:27116050

  10. Nanomembrane Containing a Nanopore in an Electrolyte Solution: A Molecular Dynamics Approach.

    PubMed

    Chen, Houyang; Ruckenstein, Eli

    2014-09-01

    Molecular dynamics simulation is used to acquire information about the characteristics of a nanographene membrane immersed in an electrolyte solution of KCl and subjected to an electric field. The membrane possesses one nanopore. It is shown that the solution contains in addition to hydrated ions, hydrated ion pairs, and hydrated clusters with more than two ions. The fractions of hydrated ions, hydrated ion pairs and hydrated clusters as well as their hydration numbers were also calculated. It was found that the hydration numbers remain constant at low electric fields but decrease at high electric fields. Under the action of an electric field, the K(+) and Cl(-) ions separate on the two sides of graphene, thus generating hydrated ion polarization layers, which result in negative charge density layers and positive ones on the left and right interfaces of the water/graphene. Thus, the neutral graphene becomes asymmetrically charged. PMID:26278246

  11. Nonresonant and resonant mode-specific intermolecular vibrational energy transfers in electrolyte aqueous solutions.

    PubMed

    Bian, Hongtao; Chen, Hailong; Li, Jiebo; Wen, Xiewen; Zheng, Junrong

    2011-10-27

    The donor/acceptor energy mismatch and vibrational coupling strength dependences of interionic vibrational energy transfer kinetics in electrolyte aqueous solutions were investigated with ultrafast multiple-dimensional vibrational spectroscopy. An analytical equation derived from the Fermi's Golden rule that correlates molecular structural parameters and vibrational energy transfer kinetics was found to be able to describe the intermolecular mode specific vibrational energy transfer. Under the assumption of the dipole-dipole approximation, the distance between anions in the aqueous solutions was obtained from the vibrational energy transfer measurements, confirmed with measurements on the corresponding crystalline samples. The result demonstrates that the mode-specific vibrational energy transfer method holds promise as an angstrom molecular ruler. PMID:21916443

  12. Frequency dispersion of the dynamic moduli of elasticity of electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Odinaev, S.; Akdodov, D. M.; Sharifov, N.

    2016-02-01

    The frequency dispersion range of the dynamic bulk relaxation modulus K(ω) and shear relaxation modulus µ(ω) of electrolyte solutions has been determined in relation to the nature of stress tensor damping in the momentum and configuration spaces. Numerical calculations have been carried out for an aqueous NaCl solution in wide frequency, temperature, and density ranges using analytical expressions obtained for K(ω) and µ(ω) for the exponential-law damping of the fluxes at a certain molecular interaction potential Φ (| {vec r} | ) and radial distribution function g( | {vec r} | ). It has been demonstrated that the frequency dispersion range of K r (v) and µ(v) for the exponential-law damping of the corresponding fluxes is narrow (˜102 Hz).

  13. Studying the frequency dispersion of the dielectric permeability of electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Odinaev, S.; Makhmadbegov, R. S.

    2016-01-01

    Analytical equations for coefficients of dielectric permeability ɛ1(ω) and dielectric losses ɛ2(ω) of electrolyte solutions are obtained, based on the relationship between complex dielectric permeability and specific conductivity coefficients. The region of frequency dispersion is considered for dynamic dielectric permeability coefficient ɛ1(ω) of an aqueous NaCl solution. Friction coefficients β a and β b , relaxation times τ a , τ b , and τ ab , and dielectric permeability coefficient ɛ1(ω) are numerically calculated for selected intermolecular interaction potentials {Φ _{ab}}(| {bar r} |) and equilibrium radial distribution functions {g_{ab}}(| {bar r} |) over a wide range of variation in density ρ, concentration c, temperature T, and frequencies ω. The theoretically calculated results for ɛ1(ω) are found to be in quantitative agreement with experimental data.

  14. Aspiration Pneumonitis Caused by Polyethylene Glycol-Electrolyte Solution Treated with Conservative Management

    PubMed Central

    Mosquera, Ricardo A.; McDonald, Mark; Samuels, Cheryl

    2014-01-01

    Polyethylene glycol (PEG) electrolyte solution, Golytely, is an osmotic laxative commonly used in preoperative bowel cleansing. In this case report, a 9-year-old boy developed aspiration pneumonitis following accidental infusion of PEG solution into his right lung following migration of his nasogastric tube (NGT). Hypoxemia and tachypnea without respiratory failure were observed after infusion. Because PEG is a nonabsorbable toxic material, previous case reports have advocated for the performance of bronchoalveolar lavage (BAL) in the treatment of PEG pneumonitis. With close monitoring, our patient was able to be successfully treated without the need for invasive interventions including BAL or intubation. Generalizations about PEG absorption in the lung based on its permeability in the gastrointestinal tract should not deter the use of more conservative treatment in the appropriate patient. PMID:24955273

  15. Improvement of sensitivity of electrolyte cathode discharge atomic emission spectrometry (ELCAD-AES) for mercury using acetic acid medium.

    PubMed

    Shekhar, R

    2012-05-15

    A method has been developed to improve the sensitivity of the electrolyte cathode discharge atomic emission spectrometry (ELCAD-AES) for mercury determination. Effects of various low molecular weight organic solvents at different volume percentages as well as at different acid molarities on the mercury signal were investigated using ELCAD-AES. The addition of few percent of organic solvent, acetic acid produced significant enhancement in mercury signal. Acetic acid of 5% (v/v) with the 0.2M acidity has been found to give 500% enhancement for mercury signal in flow injection mode. Under the optimized parameters the repeatability, expressed as the percentage relative standard deviation of spectral peak area for mercury with 5% acetic acid was found to be 10% for acid blank solution and 5% for 20 ng/mL mercury standard based on multiple measurements with a multiple sample loading in flow injection mode. Limit of detection of this method was determined to be 2 ng/mL for inorganic mercury. The proposed method has been validated by determining mercury in certified reference materials, Tuna fish (IAEA-350) and Aquatic plant (BCR-060). Accuracy of the method for the mercury determination in the reference materials has been found to be between 3.5% and 5.9%. This study enhances the utility of ELCAD-AES for various types of biological and environmental materials to quantify total mercury at very low levels. PMID:22483872

  16. Novel, electrolyte solutions comprising fully inorganic salts with high anodic stability for rechargeable magnesium batteries

    SciTech Connect

    Doe, RE; Han, R; Hwang, J; Gmitter, AJ; Shterenberg, I; Yoo, HD; Pour, N; Aurbach, D

    2014-01-01

    Herein the first inorganic magnesium salt solution capable of highly reversible magnesium electrodeposition is presented. Synthesized by acid-base reaction of MgCl2 and Lewis acidic compounds such as AlCl3, this salt class demonstrates upwards of 99% Coulombic efficiency, deposition overpotential of <200 mV, and anodic stability of 3.1 V.

  17. Evaluation of the tapered PMMA fiber sensor response due to the ionic interaction within electrolytic solutions

    NASA Astrophysics Data System (ADS)

    Batumalay, M.; Rahman, H. A.; Kam, W.; Ong, Y. S.; Ahmad, F.; Zakaria, R.; Harun, S. W.; Ahmad, H.

    2014-01-01

    A tapered plastic multimode fiber (PMMA) optical sensor is proposed and demonstrated for continuous monitoring of solutions based on different concentration of sodium chloride and glucose in deionized water The tapered PMMA fiber was fabricated using an etching method involving deionized water and acetone to achieve a waist diameter and length of 0.45 mm and 10 mm, respectively, and was used to investigate the effect of straight, U-shape, and knot shape against concentration for both sodium chloride and glucose. The results show that there is a strong dependence of the electrolytic and non-electrolytic nature of the chemical solutions on the sensor output. It is found that the sensitivity of the sodium chloride concentration sensor with the straight tapered fiber probe was 0.0023 mV/%, which was better than the other probe arrangements of U-shape and knot. Meanwhile, the glucose sensor performs with the highest sensitivity of 0.0026 mV/wt % with the knot-shaped tapered fiber probe. In addition, a tapered PMMA probe which was coated by silver film was fabricated and demonstrated using calcium hypochlorite (G70) solution. The working mechanism of such a device is based on the observed increment in the transmission of the sensor that is immersed in solutions of higher concentration. As the concentration varies from 0 ppm to 6 ppm, the output voltage of the sensor increases linearly from 3.61 mV to 4.28 mV with a sensitivity of 0.1154 mV/ppm and a linearity of more than 99.47%. The silver film coating increases the sensitivity of the proposed sensor due to the effective cladding refractive index, which increases with the coating and thus allows more light to be transmitted from the tapered fiber.

  18. Electrolytic regeneration of acid cupric chloride printed circuit board etchant. Final report, August 1, 1995--October 31, 1996

    SciTech Connect

    Oxley, J.E.; Smialek, R.J.

    1997-04-18

    The overall objective of this ERIP program was to make substantial progress in further developing a process for electrolytic regeneration of acid cupric chloride etchant - a process which was initially demonstrated in in-house studies and EPA Phase I and Phase II SBIRs. Specific objectives of the work were: (1) to define optimum system operating conditions by conducting a systematic study of process parameters, (2) to develop or find a superior electrolyic cell separator material, (3) to determine an optimum activation procedure for the flow-through carbon/graphite felt electrodes which are so critical to process performance, (4) to demonstrate - on the pre-prototype scale - electrolytic compensation for oxygen ingress - which causes etchant solution growth, and (5) to begin engineering design work on a prototype-scale regeneration unit. Parametric studies looked at the effect that key plating parameters have on copper deposit quality. Parameters tested included (a) velocity past the plating cathodes, (b) copper concentration in the catholyte solution from which the copper is being plated, (c) plating current density, and (d) catholyte cupric ion concentration. The most significant effects were obtained for velocity changes. The work showed that catholyte velocities above 0.5 ft/sec were needed to get adequate plating at 77.5 mA/cm{sup 2} and higher currents, and that even higher flow was better.

  19. Separator for starved electrolyte lead/acid battery. [perlite and glass fiber mixture

    SciTech Connect

    Bilawsky, P.D.; Cain, C.W.; Gross, S.E.; Scheffel, N.B.

    1980-11-11

    Compositions and papers made therefrom useful as separator materials in starved electrolyte lead/acid batteries are described. The compositions comprise a mixture of 30% to 80% by weight of perlite and 20% to 70% by weight of glass fibers. The glass fibers have diameters in the range of from 0.3 to 1.0 micrometers while the perlite has particle sizes in the range of from about 3 to about 100 micrometers.

  20. Nonequilibrium 2-Hydroxyoctadecanoic Acid Monolayers: Effect of Electrolytes

    SciTech Connect

    Lendrum, Conrad D.; Ingham, Bridget; Lin, Binhua; Meron, Mati; Toney, Michael F.; McGrath, Kathryn M.

    2012-02-06

    2-Hydroxyacids display complex monolayer phase behavior due to the additional hydrogen bonding afforded by the presence of the second hydroxy group. The placement of this group at the position {alpha} to the carboxylic acid functionality also introduces the possibility of chelation, a utility important in crystallization including biomineralization. Biomineralization, like many biological processes, is inherently a nonequilibrium process. The nonequilibrium monolayer phase behavior of 2-hydroxyoctadecanoic acid was investigated on each of pure water, calcium chloride, sodium bicarbonate and calcium carbonate crystallizing subphases as a precursor study to a model calcium carbonate biomineralizing system, each at a pH of {approx}6. The role of the bicarbonate co-ion in manipulating the monolayer structure was determined by comparison with monolayer phase behavior on a sodium chloride subphase. Monolayer phase behavior was probed using surface pressure/area isotherms, surface potential, Brewster angle microscopy, and synchrotron-based grazing incidence X-ray diffraction and X-ray reflectivity. Complex phase behavior was observed for all but the sodium chloride subphase with hydrogen bonding, electrostatic and steric effects defining the symmetry of the monolayer. On a pure water subphase hydrogen bonding dominates with three phases coexisting at low pressures. Introduction of calcium ions into the aqueous subphase ensures strong cation binding to the surfactant head groups through chelation. The monolayer becomes very unstable in the presence of bicarbonate ions within the subphase due to short-range hydrogen bonding interactions between the monolayer and bicarbonate ions facilitated by the sodium cation enhancing surfactant solubility. The combined effects of electrostatics and hydrogen bonding are observed on the calcium carbonate crystallizing subphase.

  1. Electrical conductivity of acidic sulfate solution

    NASA Astrophysics Data System (ADS)

    Majima, Hiroshi; Peters, Ernest; Awakura, Yasuhiro; Park, Sung Kook

    1987-03-01

    The electrical conductivities of the aqueous solution system of H2SO4-MSO4 (involving ZnSO4, MgSO4, Na2SO4, and (NH4)2SO4), reported by Tozawa et al., were examined in terms of a (H2O) and H+ ion concentration. The equations to compute the concentrations of various species in aqueous sulfuric acid solutions containing metal sulfates were derived for a typical example of the H2SO4-ZnSO4-MgSO4-(Na2SO4)-H2O system. It was found that the H+ ion concentrations in concentrated sulfuric acid solutions corresponding to practical zinc electrowinning solutions are very high and remain almost constant with or without the addition of metal sulfates. The addition of metal sulfates to aqueous sulfuric acid solution causes a decrease in electrical conductivity, and this phenomenon is attributed to a decrease in water activity, which reflects a decrease in the amount of free water. The relationship between conductivity and water activity at a constant H+ ion concentration is independent of the kind of sulfates added. On the other hand, any increase in H+ ion concentration results in an increase in electrical conductivity. A novel method for the prediction of electrical conductivity of acidic sulfate solution is proposed that uses the calculated data of water activity and the calculated H+ ion concentration. Also, the authors examined an extension of the Robinson-Bower equation to calculate water activity in quarternary solutions based on molarity instead of molality, and found that such calculated values are in satisfactory agreement with those determined experimentally by a transpiration method.

  2. Enhanced Performance of PbS-quantum-dot-sensitized Solar Cells via Optimizing Precursor Solution and Electrolytes

    NASA Astrophysics Data System (ADS)

    Tian, Jianjun; Shen, Ting; Liu, Xiaoguang; Fei, Chengbin; Lv, Lili; Cao, Guozhong

    2016-03-01

    This work reports a PbS-quantum-dot-sensitized solar cell (QDSC) with power conversion efficiency (PCE) of 4%. PbS quantum dots (QDs) were grown on mesoporous TiO2 film using a successive ion layer absorption and reaction (SILAR) method. The growth of QDs was found to be profoundly affected by the concentration of the precursor solution. At low concentrations, the rate-limiting factor of the crystal growth was the adsorption of the precursor ions, and the surface growth of the crystal became the limiting factor in the high concentration solution. The optimal concentration of precursor solution with respect to the quantity and size of synthesized QDs was 0.06 M. To further increase the performance of QDSCs, the 30% deionized water of polysulfide electrolyte was replaced with methanol to improve the wettability and permeability of electrolytes in the TiO2 film, which accelerated the redox couple diffusion in the electrolyte solution and improved charge transfer at the interfaces between photoanodes and electrolytes. The stability of PbS QDs in the electrolyte was also improved by methanol to reduce the charge recombination and prolong the electron lifetime. As a result, the PCE of QDSC was increased to 4.01%.

  3. Enhanced Performance of PbS-quantum-dot-sensitized Solar Cells via Optimizing Precursor Solution and Electrolytes

    PubMed Central

    Tian, Jianjun; Shen, Ting; Liu, Xiaoguang; Fei, Chengbin; Lv, Lili; Cao, Guozhong

    2016-01-01

    This work reports a PbS-quantum-dot-sensitized solar cell (QDSC) with power conversion efficiency (PCE) of 4%. PbS quantum dots (QDs) were grown on mesoporous TiO2 film using a successive ion layer absorption and reaction (SILAR) method. The growth of QDs was found to be profoundly affected by the concentration of the precursor solution. At low concentrations, the rate-limiting factor of the crystal growth was the adsorption of the precursor ions, and the surface growth of the crystal became the limiting factor in the high concentration solution. The optimal concentration of precursor solution with respect to the quantity and size of synthesized QDs was 0.06 M. To further increase the performance of QDSCs, the 30% deionized water of polysulfide electrolyte was replaced with methanol to improve the wettability and permeability of electrolytes in the TiO2 film, which accelerated the redox couple diffusion in the electrolyte solution and improved charge transfer at the interfaces between photoanodes and electrolytes. The stability of PbS QDs in the electrolyte was also improved by methanol to reduce the charge recombination and prolong the electron lifetime. As a result, the PCE of QDSC was increased to 4.01%. PMID:26975216

  4. Improved fiber optic device for in situ determination of electrolyte stratification in lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Gajdátsy, G.; Benedek, F.; Kokavecz, J.; Szabó, G.; Kornis, J.

    2009-12-01

    A three-channel, highly sensitive, fiber optic device is presented to measure acid concentration in lead-acid batteries during their operation. The refractive index and thereby the concentration of sulfuric acid is measured by a bent, silica glass fiber tip, stripped off its cladding. Sensor heads of the device are small enough to be inserted at different positions in the cell of an ordinary, flooded lead-acid battery. Measuring the concentration of the electrolyte at different depths of the battery cell, acid stratification can be accurately determined. During the test of the instrument, about 0.3 Hz temporal and 0.05 wt % concentration resolutions were achieved while the temperature drift was found to be -0.25 wt %/°C.

  5. Improved fiber optic device for in situ determination of electrolyte stratification in lead-acid batteries.

    PubMed

    Gajdátsy, G; Benedek, F; Kokavecz, J; Szabó, G; Kornis, J

    2009-12-01

    A three-channel, highly sensitive, fiber optic device is presented to measure acid concentration in lead-acid batteries during their operation. The refractive index and thereby the concentration of sulfuric acid is measured by a bent, silica glass fiber tip, stripped off its cladding. Sensor heads of the device are small enough to be inserted at different positions in the cell of an ordinary, flooded lead-acid battery. Measuring the concentration of the electrolyte at different depths of the battery cell, acid stratification can be accurately determined. During the test of the instrument, about 0.3 Hz temporal and 0.05 wt % concentration resolutions were achieved while the temperature drift was found to be -0.25 wt %/degrees C. PMID:20059171

  6. Lead, cadmium and aluminum in Canadian infant formulae, oral electrolytes and glucose solutions

    PubMed Central

    Dabeka, Robert; Fouquet, Andre; Belisle, Stephane; Turcotte, Stephane

    2011-01-01

    Lead (Pb), cadmium (Cd) and aluminum (Al) were determined in 437 individual samples of infant formulae, oral electrolytes and 5% glucose solutions available in Canada. In the electrolytes, Cd and Pb concentrations were all below 0.01 and 0.041 ng g−1, respectively. In the 5% glucose solutions, Pb and Cd levels averaged 0.01 and 0.09 ng g−1, respectively. Reported on an as-consumed basis, Pb levels in milk- and soya-based formulae averaged 0.90 and 1.45 ng g−1, respectively, while Cd levels averaged 0.23 and 1.18 ng g−1, respectively Average Al levels on an as-consumed basis were 440 ng g−1 (range 10–3400 ng g−1) in milk-based formulae and 730 ng g−1 (range 230–1100 ng g−1) in soy-based formulae. Al concentrations increased in the following order: plain formula < low-iron formula < iron-supplemented formula < casein hydrolysate formula ≈ premature formula ≤ soy formula. For example, in the powdered formulae, average Al concentrations were 18 ng g−1 for plain milk-based, 37 ng g−1 for low-iron, 128 ng g−1 for iron supplemented, 462 ng g−1 for lactose-free, 518 ng g−1 for hypoallergenic and 619 ng g−1 for soy-based formula. Al concentrations, as-consumed, increased with decreasing levels of concentration: powder < concentrated liquid < ready-to-use. Formulae stored in glass bottles contained between 100 and 300 ng g−1 more Al than the same formulae stored in cans. The source of the increased Al did not appear to be the glass itself, because most electrolytes and glucose solutions, also stored in glass, contained less than 8 ng g−1 Al. Corresponding differences in Pb and Cd levels were not observed. Al concentrations varied substantially among manufacturers; however, all manufacturers were able to produce plain milk-based formulae containing less than 50 ng g−1 Al, i.e. within the range of Al concentrations found in human milk. Next to soya-based and hypoallergenic formulae, premature formulae contained among the highest

  7. Successful Stabilization of Graphene Oxide in Electrolyte Solutions: Enhancement of Bio-functionalization and Cellular Uptake

    PubMed Central

    Hong, Bong Jin; Compton, Owen C.; An, Zhi; Eryzazici, Ibrahim; Nguyen, SonBinh T.

    2013-01-01

    Aqueous dispersions of graphene oxide are inherently unstable in the presence of electrolytes, which screen the electrostatic surface charge on these nanosheets and induce irreversible aggregation. Two complementary strategies, utilizing either electrostatic or steric stabilization, have been developed to enhance the stability of graphene oxide in electrolyte solutions, allowing it to stay dispersed in cell culture media and serum. The electrostatic stabilization approach entails further oxidation of graphene oxide to low C/O ratio (~1.03) and increases ionic tolerance of these nanosheets. The steric stabilization technique employs an amphiphilic block copolymer that serves as a non-covalently bound surfactant to minimize the aggregate-induced nanosheets-nanosheet interactions. Both strategies can stabilize graphene oxide nanosheets with large dimensions (>300 nm) in biological media, allowing for an enhancement of >250% in the bioconjugation efficiency of streptavidin in comparison to untreated nanosheets. Notably, both strategies allow the stabilized nanosheets to be readily uptake by cells, demonstrating their excellent performance as potential drug delivery vehicles. PMID:22017285

  8. Mechanism of hydrofluoric acid formation in ethylene carbonate electrolytes with fluorine salt additives

    NASA Astrophysics Data System (ADS)

    Tebbe, Jonathon L.; Fuerst, Thomas F.; Musgrave, Charles B.

    2015-11-01

    We utilized density functional theory to examine HF generation in lithium-ion battery electrolytes from reactions between H2O and the decomposition products of three electrolyte additives: LiPF6, LiPOF4, and LiAsF6. Decomposition of these additives produces PF5, AsF5, and POF3 along with LiF precipitates. We found PF5 and AsF5 react with H2O in two sequential steps to form two HF molecules and POF3 and AsOF3, respectively. PF5 (or AsF5) complexes with H2O and undergoes ligand exchange to form HF and PF4OH (AsF4OH) with an activation barrier of 114.2 (30.5) kJ mol-1 and reaction enthalpy of 14.6 (-11.3) kJ mol-1. The ethylene carbonate (EC) electrolyte forms a Lewis acid-base complex with the PF4OH (AsF4OH) product, reducing the barrier to HF formation. Reactions of POF3 were examined and are not characterized by complexation of POF3 with H2O or EC, while PF5 and AsF5 complex favorably with H2O and EC. HF formation from POF3 occurs with a reaction enthalpy of -3.8 kJ mol-1 and a 157.7 kJ mol-1 barrier, 43.5 kJ mol-1 higher than forming HF from PF5. HF generation in electrolytes employing LiPOF4 should be significantly lower than those using LiPF6 or LiAsF6 and LiPOF4 should be further investigated as an alternative electrolyte additive.

  9. Atomically resolved three-dimensional structures of electrolyte aqueous solutions near a solid surface

    NASA Astrophysics Data System (ADS)

    Martin-Jimenez, Daniel; Chacon, Enrique; Tarazona, Pedro; Garcia, Ricardo

    2016-07-01

    Interfacial liquid layers play a central role in a variety of phenomena ranging from friction to molecular recognition. Liquids near a solid surface form an interfacial layer where the molecular structure is different from that of the bulk. Here we report atomic resolution three-dimensional images of electrolyte solutions near a mica surface that demonstrate the existence of three types of interfacial structures. At low concentrations (0.01-1 M), cations are adsorbed onto the mica. The cation layer is topped by a few hydration layers. At higher concentrations, the interfacial layer extends several nanometres into the liquid. It involves the alternation of cation and anion planes. Fluid Density Functional calculations show that water molecules are a critical factor for stabilizing the structure of the interfacial layer. The interfacial layer stabilizes a crystal-like structure compatible with liquid-like ion and solvent mobilities. At saturation, some ions precipitate and small crystals are formed on the mica.

  10. Novel Proton Conducting Solid Bio-polymer Electrolytes Based on Carboxymethyl Cellulose Doped with Oleic Acid and Plasticized with Glycerol

    NASA Astrophysics Data System (ADS)

    Chai, M. N.; Isa, M. I. N.

    2016-06-01

    The plasticized solid bio-polymer electrolytes (SBEs) system has been formed by introducing glycerol (Gly) as the plasticizer into the carboxymethyl cellulose (CMC) doped with oleic acid (OA) via solution casting techniques. The ionic conductivity of the plasticized SBEs has been studied using Electrical Impedance Spectroscopy. The highest conductivity achieved is 1.64 × 10‑4 S cm‑1 for system containing 40 wt. % of glycerol. FTIR deconvolution technique had shown that the conductivity of CMC-OA-Gly SBEs is primarily influenced by the number density of mobile ions. Transference number measurement has shown that the cation diffusion coefficient and ionic mobility is higher than anion which proved the plasticized polymer system is a proton conductor.

  11. Novel Proton Conducting Solid Bio-polymer Electrolytes Based on Carboxymethyl Cellulose Doped with Oleic Acid and Plasticized with Glycerol

    PubMed Central

    Chai, M. N.; Isa, M. I. N.

    2016-01-01

    The plasticized solid bio-polymer electrolytes (SBEs) system has been formed by introducing glycerol (Gly) as the plasticizer into the carboxymethyl cellulose (CMC) doped with oleic acid (OA) via solution casting techniques. The ionic conductivity of the plasticized SBEs has been studied using Electrical Impedance Spectroscopy. The highest conductivity achieved is 1.64 × 10−4 S cm−1 for system containing 40 wt. % of glycerol. FTIR deconvolution technique had shown that the conductivity of CMC-OA-Gly SBEs is primarily influenced by the number density of mobile ions. Transference number measurement has shown that the cation diffusion coefficient and ionic mobility is higher than anion which proved the plasticized polymer system is a proton conductor. PMID:27265642

  12. Electrolytic dissolver

    DOEpatents

    Wheelwright, E.J.; Fox, R.D.

    1975-08-26

    This patent related to an electrolytic dissolver wherein dissolution occurs by solution contact including a vessel of electrically insulative material, a fixed first electrode, a movable second electrode, means for insulating the electrodes from the material to be dissolved while permitting a free flow of electrolyte therebetween, means for passing a direct current between the electrodes and means for circulating electrolyte through the dissolver. (auth)

  13. Enhanced catalytic performance of Pd catalyst for formic acid electrooxidation in ionic liquid aqueous solution

    NASA Astrophysics Data System (ADS)

    Feng, Yuan-Yuan; Yin, Qian-Ying; Lu, Guo-Ping; Yang, Hai-Fang; Zhu, Xiao; Kong, De-Sheng; You, Jin-Mao

    2014-12-01

    A protic ionic liquid (IL), n-butylammonium nitrate (N4NO3), is prepared and employed as the electrolyte for formic acid electrooxidation reaction (FAOR) on Pd catalysts. The oxidation peak potential of FAOR in the IL solution shows about a 200 mV negative shift as compared with those in traditional H2SO4/HClO4 electrolytes, suggesting that FAOR can be more easily carried out on Pd catalysts in IL media. The catalytic properties of Pd toward FAOR are not only dependent on the concentration of IL, as a consequence of the varied electronic conductivity of the IL solution, but also on the high potential limit of the cyclic voltammograms. When the Pd catalyst is cycled up to 1.0 V (vs. SCE), which induces a significant oxidation of Pd, it shows ca. 4.0 times higher activity than that not subjected to the Pd oxidation (up to 0.6 V). The Pd oxides, which are more easily formed in IL solution than in traditional H2SO4/HClO4 electrolytes, may play a crucial role in increasing the catalytic activities of Pd toward FAOR. Our work would shed new light on the mechanism of FAOR and highlight the potential applications of IL as green and environment-friendly electrolytes in fuel cells and other technologies.

  14. Speciation in aqueous solutions of nitric acid.

    PubMed

    Hlushak, S; Simonin, J P; De Sio, S; Bernard, O; Ruas, A; Pochon, P; Jan, S; Moisy, P

    2013-02-28

    In this study, speciation in aqueous solutions of nitric acid at 25 °C was assessed in two independent ways. First, Raman experiments were carried out and interpreted in terms of free nitrate ions, ion pairs and neutral HNO(3) molecules. In parallel, a model was developed to account for the formation of these two kinds of pairs. It was based on an extension of the binding mean spherical approximation (BiMSA), or associative MSA (AMSA), in which the size and the charge of the ions in the chemical pair may differ from those of the free ions. A simultaneous fit of the osmotic coefficient and of the proportion of free ions (obtained from Raman spectroscopy experiments) led to an estimation of the speciation in nitric acid solutions. The result obtained using this procedure was compared with the estimation obtained from the Raman experiments. PMID:23258765

  15. Alkaline earth cation extraction from acid solution

    DOEpatents

    Dietz, Mark; Horwitz, E. Philip

    2003-01-01

    An extractant medium for extracting alkaline earth cations from an aqueous acidic sample solution is described as are a method and apparatus for using the same. The separation medium is free of diluent, free-flowing and particulate, and comprises a Crown ether that is a 4,4'(5')[C.sub.4 -C.sub.8 -alkylcyclohexano]18-Crown-6 dispersed on an inert substrate material.

  16. Epoxyeicosatrienoic Acids Affect Electrolyte Transport in Renal Tubular Epithelial Cells: Dependence on Cyclooxygenase and Cell Polarity

    PubMed Central

    Nüsing, Rolf M.; Schweer, Horst; Fleming, Ingrid; Zeldin, Darryl C.; Wegmann, Markus

    2007-01-01

    We investigated the effects of epoxyeicosatrienoic acids (EETs) on ion transport in the polarized renal distal tubular cell line, MDCK C7. Of the four EET regioisomers (5,6-EET, 8,9-EET, 11,12-EET, and 14,15-EET) studied, only apical, but not basolateral, application of 5,6-EET increased short circuit current (Isc) with kinetics similar to those of arachidonic acid. The ion transport was blocked by preincubation with the cyclooxygenase inhibitor indomethacin or with the chloride channel blocker NPPB. Further, both a Cl−-free bath solution and the Ca2+ antagonist verapamil blocked 5,6-EET-induced ion transport. Although the presence of the PGE2 receptors EP2, EP3, and EP4 was demonstrated, apically added PGE2 was ineffective and basolaterally added PGE2 caused a different kinetics in ion transport compared to 5,6-EET. Moreover, PGE2 sythesis in MDCK C7 cells was unaffected by 5,6-EET treatment. GC/MS/MS analysis of cell supernatants revealed the presence of the biologically inactive 5,6-dihydroxy-PGE1 in 5,6-EET-treated cells, but not in control cells. Indomethacin suppressed the formation of 5,6-dihydroxy-PGE1. 5,6-epoxy-PGE1 the precursor of 5,6-dihydroxy-PGE1, caused a similar ion transport as 5,6-EET. Cytochrome P450 enzymes homolog to human CYP2C8, CYP2C9, and CYP2J2 protein were detected immunologically in the MDCK C7 cells. Our findings suggest that 5,6-EET affects Cl-transport in renal distal tubular cells independent of PGE2 but by a mechanism, dependent on its conversion to 5,6-epoxy-PGE1 by cyclooxygenase. We suggest a role for this P450 epoxygenase product in the regulation of electrolyte transport, especially as a saluretic compound acting from the luminal side of tubular cells in the mammalian kidney. PMID:17494091

  17. Epoxyeicosatrienoic acids affect electrolyte transport in renal tubular epithelial cells: dependence on cyclooxygenase and cell polarity.

    PubMed

    Nüsing, Rolf M; Schweer, Horst; Fleming, Ingrid; Zeldin, Darryl C; Wegmann, Markus

    2007-07-01

    We investigated the effects of epoxyeicosatrienoic acids (EETs) on ion transport in the polarized renal distal tubular cell line, Madin-Darby canine kidney (MDCK) C7. Of the four EET regioisomers (5,6-EET, 8,9-EET, 11,12-EET, and 14,15-EET) studied, only apical, but not basolateral, application of 5,6-EET increased short-circuit current (I(sc)) with kinetics similar to those of arachidonic acid. The ion transport was blocked by preincubation with the cyclooxygenase inhibitor indomethacin or with the chloride channel blocker NPPB. Furthermore, both a Cl(-)-free bath solution and the Ca(2+) antagonist verapamil blocked 5,6-EET-induced ion transport. Although the presence of the PGE(2) receptors EP2, EP3, and EP4 was demonstrated, apically added PGE(2) was ineffective and basolaterally added PGE(2) caused a different kinetics in ion transport compared with 5,6-EET. Moreover, PGE(2) synthesis in MDCK C7 cells was unaffected by 5,6-EET treatment. GC/MS/MS analysis of cell supernatants revealed the presence of the biologically inactive 5,6-dihydroxy-PGE(1) in 5,6-EET-treated cells, but not in control cells. Indomethacin suppressed the formation of 5,6-dihydroxy-PGE(1). 5,6-Epoxy-PGE(1), the precursor of 5,6-dihydroxy-PGE(1), caused a similar ion transport as 5,6-EET. Cytochrome P-450 enzymes homolog to human CYP2C8, CYP2C9, and CYP2J2 protein were detected immunologically in the MDCK C7 cells. Our findings suggest that 5,6-EET affects Cl(-) transport in renal distal tubular cells independent of PGE(2) but by a mechanism, dependent on its conversion to 5,6-epoxy-PGE(1) by cyclooxygenase. We suggest a role for this P450 epoxygenase product in the regulation of electrolyte transport, especially as a saluretic compound acting from the luminal side of tubular cells in the mammalian kidney. PMID:17494091

  18. Isotherm-based thermodynamic model for electrolyte and nonelectrolyte solutions incorporating long- and short-range electrostatic interactions.

    PubMed

    Ohm, Peter B; Asato, Caitlin; Wexler, Anthony S; Dutcher, Cari S

    2015-04-01

    The activities of solutes and solvents in solutions govern numerous physical phenomena in a wide range of practical applications. In prior work, we used statistical mechanics and multilayer adsorption isotherms to develop a transformative model for capturing thermodynamic properties of multicomponent aqueous solutions over the entire concentration range (Dutcher et al. J. Phys. Chem. 2011, 2012, 2013). That model needed only a few adsorption energy values to represent the solution thermodynamics of each solute. In the current work, we posit that the adsorption energies are due to dipole-dipole electrostatic forces in solute-solvent and solvent-solvent interactions. This hypothesis was tested in aqueous solutions on (a) 37 1:1 electrolytes, over a range of cation sizes, from H(+) to tetrabutylammonium, for common anions including Cl(-), Br(-), I(-), NO3(-), OH(-), ClO4(-), and (b) 20 water-soluble organic molecules including alcohols and polyols. For both electrolytes and organic solutions, the energies of adsorption can be calculated with the dipole moments of the solvent, molecular size of the solvent and solute, and the solvent-solvent and solvent-solute intermolecular bond lengths. Many of these physical properties are available in the literature, with the exception of the solute-solvent intermolecular bond lengths. For those, predictive correlations developed here enable estimation of solute and solvent solution activities for which there are little or no activity data. PMID:25685901

  19. Studies on electrolyte formulations to improve life of lead acid batteries working under partial state of charge conditions

    NASA Astrophysics Data System (ADS)

    Hernández, J. C.; Soria, M. L.; González, M.; García-Quismondo, E.; Muñoz, A.; Trinidad, F.

    For decades, valve regulated lead acid batteries with gel electrolyte have proved their excellent performance in deep cycling applications. However, their higher cost, when compared with flooded batteries, has limited their use in cost sensitive applications, such as automotive or PV installations. The use of flooded batteries in deep or partial state of charge working conditions leads to limited life due to premature capacity loss provoked by electrolyte stratification. Different electrolyte formulations have been tested, in order to achieve the best compromise between cost and life performance. Work carried out included electrochemical studies in order to determine the electrolyte stability and diffusional properties, and kinetic studies to check the processability of the electrolyte formulation. Finally, several 12 V batteries have been assembled and tested according to different ageing profiles.

  20. Reaction behavior of Ni-Re alloys during direct current polarization in sulfuric acid solutions

    NASA Astrophysics Data System (ADS)

    Bryukvin, V. A.; Elemesov, T. B.; Levchuk, O. M.; Bol'shikh, A. O.

    2016-01-01

    The macrokinetic regularities of the reactivity of synthesized Ni-Re (20 and 60 wt %) alloys in a sulfuric acid solution (100 g/L, 25-40°C) during direct current polarization are studied using physicochemical methods. The phase composition of the synthesized alloys is determined by the formation of solid solutions as a function of the initial Ni/Re weight ratio. These are two types of nickel solid solutions (Ni16Re0.2 and Ni14Re0.9) and one rhenium solution (Ni1.1Re). These solid solutions are anodically oxidized in the sequence of their structural rearrangement Ni16Re0.2 → Ni14Re0.9 → Ni1.1Re with a combined transition of the metals into an electrolyte solution. These solid solutions provide the reduction of Ni3+ to Ni2+ due to the depolarization ability of rhenium, being their component.

  1. Acidities of Water and Methanol in Aqueous Solution and DMSO

    ERIC Educational Resources Information Center

    Gao, Daqing

    2009-01-01

    The relative acidities of water and methanol have been a nagging issue. In gas phase, methanol is more acidic than water by 36.0 kJ/mol; however, in aqueous solution, the acidities of methanol and water are almost identical. The acidity of an acid in solution is determined by both the intrinsic gas-phase ionization Gibbs energy and the solvent…

  2. Isotherm-Based Thermodynamic Models for Solute Activities of Organic Acids with Consideration of Partial Dissociation.

    PubMed

    Nandy, Lucy; Ohm, Peter B; Dutcher, Cari S

    2016-06-23

    Organic acids make up a significant fraction of the organic mass in atmospheric aerosol particles. The calculation of gas-liquid-solid equilibrium partitioning of the organic acid is therefore critical for accurate determination of atmospheric aerosol physicochemical properties and processes such as new particle formation and activation to cloud condensation nuclei. Previously, an adsorption isotherm-based statistical thermodynamic model was developed for capturing solute concentration-activity relationships for multicomponent aqueous solutions over the entire concentration range (Dutcher et al. J. Phys. Chem. C/A 2011, 2012, 2013), with model parameters for energies of adsorption successfully related to dipole-dipole electrostatic forces in solute-solvent and solvent-solvent interactions for both electrolytes and organics (Ohm et al. J. Phys. Chem. A 2015). However, careful attention is needed for weakly dissociating semivolatile organic acids. Dicarboxylic acids, such as malonic acid and glutaric acid are treated here as a mixture of nondissociated organic solute (HA) and dissociated solute (H(+) + A(-)). It was found that the apparent dissociation was greater than that predicted by known dissociation constants alone, emphasizing the effect of dissociation on osmotic and activity coefficient predictions. To avoid additional parametrization from the mixture approach, an expression was used to relate the Debye-Hückel hard-core collision diameter to the adjustable solute-solvent intermolecular distance. An improved reference state treatment for electrolyte-organic aqueous mixtures, such as that observed here with partial dissociation, has also been proposed. This work results in predictive correlations for estimation of organic acid and water activities for which there is little or no activity data. PMID:27222917

  3. The rheology of oxide dispersions and the role of concentrated electrolyte solutions

    SciTech Connect

    Biggs, Simon; Tindley, Amy

    2007-07-01

    Stability control of particulate dispersions is critical to a wide range of industrial processes. In the UK nuclear industry, significant volumes of waste materials arising from the corrosion products of Magnox fuel rods currently require treatment and storage. The majority of this waste is present as aqueous dispersions of oxide particulates. Treatment of these dispersions will require a variety of unit operations including mobilisation, transport and solid- liquid separation. Typically these processes must operate across a narrow optimal range of pH and the dispersions are, almost without exception, found in complex electrolyte conditions of high overall concentration. Knowledge of the behaviour of oxides in various electrolyte conditions and over a large pH range is essential for the efficient design and control of any waste processing approach. The transport properties of particle dispersions are characterised by the rheological properties. It is well known that particle dispersion rheology is strongly influenced by particle-particle interaction forces, and that particle-particle interactions are strongly influenced by adsorbed ions on the particle surfaces. Here we correlate measurements of the shear yield stress and the particle zeta potentials to provide insight as to the role of ions in moderating particle interactions. The zeta potential of model TiO{sub 2} suspensions were determined (Colloidal Dynamics Zeta Probe) over a range of pH for a series of alkali metal halides and quaternary ammonium halides at a range of solution concentrations (0.001 M - 1 M). The results show some surprising co-ion effects at high electrolyte concentrations (>0.5 M) and indicate that even ions generally considered to be indifferent induce a shift in iso-electric point (i.e.p.) which is inferred as being due to specific adsorption of ions. The shear yield stress values of concentrated titania dispersions were measured using a Bohlin C-VOR stress controlled rheometer. The shear

  4. Relevance of Solvent Characteristics on Ion-Binding and the Structure Formation of Neutral Polymers in Electrolyte Solutions

    NASA Astrophysics Data System (ADS)

    Faiza Hakem, Ilhem; Lal, Jyotsana; Bockstaller, Michael

    2006-03-01

    Polymers carrying functional groups constituted of heteroatoms are omnipresent in biology and polymer technology, for example in the development of solid state polymer electrolytes. When dissolved in polar solvents, these polymers can coordinate ions that result in an effective transformation of the neutral polymer into a weakly charged polyelectrolyte as indicated by the characteristic changes in the polymers solution characteristics. In our contribution we discuss the implications of solvent characteristics -- i.e. dielectric constant and hydrogen bonding capacity -- and the ion-strength of the added electrolyte on the polymer-ion coordination as well as polymer solution characteristics. A mean-field model to predict the amount of ion-coordination is presented and validated for the particular case of poly(oxy ethylene)/salt solutions. The Random Phase Approximation (RPA) is applied to extract quantitative information about the coordination of ions to the polymer in solution from small-angle neutron scattering (SANS) data.

  5. Electrocapillarity of an electrolyte solution in a nanoslit with overlapped electric double layer: Continuum approach

    NASA Astrophysics Data System (ADS)

    Lee, Jung A.; Kang, In Seok

    2014-09-01

    A nanoslit is a long narrow opening between two parallel plates that are nanometers apart from each other. When an electrolyte solution is present inside a nanoslit, an overlapped electrical double layer (EDL) is formed and there exist distributions of the osmotic pressure and the Maxwell stress across the nanoslit. It is well known that the total normal stress (osmotic pressure contribution + Maxwell stress contribution) in the direction normal to the nanoslit surface is uniform and the value is the same as the osmotic pressure at the centerline. On the other hand, it is not well known that the total normal stress in the direction parallel to the slit surface is not uniform. When there is an electrolyte-gas interface inside a nanoslit, this total normal stress in the direction parallel to the slit surface generates the electrocapillarity effect. In the present work, the electromechanical approach is adopted to estimate the electrocapillarity effect in terms of the slit surface potential (or the surface charge density), the gap size, and the bulk ion concentrations. In order to handle the problem analyically, it is assumed that the nanoslit problem is in the continuum range and the interface is initially flat. The deformation of the interface due to the nonuniform total normal stress along the interface is also obtained by using the first order perturbation method. The significance of the present work can be manifested by the fact that external voltage is frequently used in nanoscaled systems and the electrocapillarity effect should be considered in addition to the intrinsic capillarity due to surface tension.

  6. Pictorial Analogies XI: Concentrations and Acidity of Solutions.

    ERIC Educational Resources Information Center

    Fortman, John J.

    1994-01-01

    Presents pictorial analogies of several concepts relating to solutions for chemistry students. These include concentration of solution, strength of solution, supersaturated solution, and conjugate acid-base pairs. Among the examples are comparison of acid strength to percentage of strong soldiers or making supersaturated solution analogous to a…

  7. A hybrid Li-air battery with buckypaper air cathode and sulfuric acid electrolyte

    SciTech Connect

    Li, YF; Huang, K; Xing, YC

    2012-10-30

    We demonstrate a type of carbon nanotube based buckypaper cathode in a hybrid electrolyte Li-air battery (HyLAB) that showed outstanding discharging performances. The HyLAB has sulfuric acid as the catholyte and a large active electrode area (10 cm(2)). The active cathode layer was made from a buckypaper with 5 wt.% Pt supported on carbon nanotubes (Pt/CNTs) for oxygen reduction and evolution. A similar cathode was constructed with a catalyst of 5 wt.% Pt supported on carbon black (Pt/CB). It is demonstrated that sulfuric acid can achieve high discharging current densities while maintaining relatively high cell potentials. The cell with Pt/CNTs showed a much better performance than with Pt/CB at high current densities. The HyLAB with Pt/CNTs achieved a discharging capacity of 306 mAh/g and a cell voltage of 3.15 V at 0.2 mA/cm(2). The corresponding specific energy is 1067 Wh/kg based on the total weight of the sulfuric acid. Slow decrease in performance was observed, but it can be recovered by refilling the cell with new electrolyte after continuous discharging of more than 75 h. A charge-discharge experiment at 0.2 mA/cm(2) showed that the cell was rechargeable with a capacity of more than 300 mAh/g. (c) 2012 Elsevier Ltd. All rights reserved.

  8. Gelled-electrolyte lead/acid batteries for stationary and traction applications

    NASA Astrophysics Data System (ADS)

    May, G. J.; Lenain, P.

    The development of new ranges of valve-regulated lead/acid (VRLA) batteries for stationary and traction applications is described. These batteries are gas recombining and use gelled electrolyte, tubular positive plates cast in lead-calcium-tin alloys and a specially-designed pressure relief valve. For stationary service, comparisons are made with VRLA batteries using absorptive glass mat separators. For traction applications, the relative merits of gel technology against alternative approaches to the achievement of lower maintenance for traction batteries are discussed. Operational experience with these batteries is outlined and guidelines indicated for correct application.

  9. Surface charge density on silica in alkali and alkaline earth chloride electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Dove, Patricia M.; Craven, Colin M.

    2005-11-01

    The surface charge density of colloidal SiO 2 (Aerosil 380) was measured in alkali chloride (0.067 and 0.20 M LiCl, NaCl, and KCl) and alkaline earth chloride (0.067 M MgCl 2, CaCl 2, SrCl 2, BaCl 2) solutions. Measurements were conducted at 25°C by potentiometric titrations using the constant ionic medium method in a CO 2-free system. The experimental design measured surface charge for solutions with constant ionic strength as well as constant cation concentration. Alkali chloride solutions promote negative surface charge density in the order LiCl < NaCl < KCl to give the "regular" lyotropic behavior previously reported. In contrast, the alkaline earth chloride solutions exhibit a reversed lyotropic trend with increasing crystallographic radius where increasing negative charge is promoted in the order BaCl 2 < SrCl 2 < CaCl 2 < MgCl 2. The origin of the opposing affinity trends is probed by testing the hypothesis that this reversal is rooted in the differing solvent structuring characteristics of the IA and IIA cations at the silica-water interface. This idea arises from earlier postulations that solvent structuring effects increase entropy through solvent disordering and these gains must be much greater than the small, positive enthalpy associated with electrostatic interactions. By correlating measured charge density with a proxy for the solvent-structuring ability of cations, this study shows that silica surface charge density is maximized by those electrolytes that have the strongest effects on solvent structuring. We suggest that for a given solid material, solvation entropy has a role in determining the ionic specificity of electrostatic interactions and reiterate the idea that the concept of lyotropy is rooted in the solvent-structuring ability of cations at the interface.

  10. Structural and transport properties of Nafion in hydrobromic-acid solutions

    SciTech Connect

    Kusoglu, A; Cho, KT; Prato, RA; Weber, AZ

    2013-12-01

    Proton-exchange membranes are key solid-state ion carriers in many relevant energy technologies including flow batteries, fuel cells, and solar-fuel generators. In many of these systems, the membranes are in contact with electrolyte solutions. In this paper, we focus on the impact of different HBr, a flow-battery and exemplary acid electrolyte, external concentrations on the conductivity of Nafion, a perfluorosulfonic acid membrane that is commonly used in many energy-related applications. The peak and then decrease in conductivity is correlated with measured changes in the water and HBr content within the membrane. In addition, small-angle x-ray scattering is used to probe the nanostructure to correlate how the interactions of the bromide ion with the fixed sulfonic-acid sites impact conductivity and hydrophilic domain distance. It is also shown that membrane pretreatment has a large impact on the underlying structure/function relationship. The obtained data and results are useful for delineation of optimal operating regimes for flow batteries and similar technologies as well as in understanding underlying structure/function relationships of ionomers in electrolyte solutions. (C) 2013 Elsevier B.V. All rights reserved.

  11. Theoretical study on the sound absorption of electrolytic solutions. II. Assignments of relaxations

    NASA Astrophysics Data System (ADS)

    Yamaguchi, T.; Matsuoka, T.; Koda, S.

    2007-08-01

    The theory on the ultrasonic absorption spectrum of electrolytic solutions recently proposed by us is applied to the model system that resembles to the aqueous solution of MgSO4. The charges on ions are reduced to +/-1.5e in order to obtain the equilibrium structure by the integral equation theory. The theory reproduces the existence of two relaxations around 100 kHz and 1 GHz. The physical origin of the relaxation is analyzed based on the theoretical expression. The slower relaxation is shown to originate in the formation of contact ion pair, in harmony with the conventional assignment. The amplitude of this relaxation agrees with the experimental one fairly well. The absorption cross section is a weakly increasing function of the concentration of the salt in theory, whereas it depends little on the concentration in experiment, which is ascribed to the weaker association of the pair in the theory. The deviation from the Debye relaxation is found for the faster process, and the concentration dependence is small. The analysis shows that this relaxation stems from the coupling between the pressure and the long-range concentration fluctuation, and the concentration independence and the non-Debye relaxation are explained based on the theoretical analysis. In particular, the theory demonstrates that this process has the t-3/2 tail in the time domain, which is confirmed by numerical calculation. The deviation of the theoretical relaxation amplitude from the experimental one is elucidated in terms of the theoretical expression of the coefficient.

  12. Solvation Behavior of Short-chain Polystyrene Sulfonate in Aqueous Electrolyte Solutions: A Molecular Dyamics Study

    SciTech Connect

    Chialvo, Ariel A; Simonson, J Michael {Mike}

    2005-01-01

    We analyze the solvation behavior of short-chain polystyrene sulfonate (PSS) in aqueous electrolyte solutions by isothernal-isochoric molecular dynamics simulation to determine the solvation effects on the structure and conformation of the polyelectrolyte as a function of the aqueous environment. To that end, we study these aqueous systems including the explicit atomistic description of water, the PSS chain, and their interactions with all species in solution. In addition, we investigate the effect of the degree of sulfonation and its distribution along the PSS chain on the resulting conformation as well as solvation structure. Moreover, we assess the impact of added salts on the net charge of the PSS backbone, placing emphasis on the valence of the counterion and the extent of the ion-pair formation between the sulfonate group and the counterions. Finally, we present evidence for the so-called like-charge attraction between sulfonate groups through the formation of counterion-mediated interchain sulfonate-sulfonate and water-mediated intrachain sulfonate-sulfonate bridges, as well as between unlike counterion-counterion interactions.

  13. Electrolyte pore/solution partitioning by expanded grand canonical ensemble Monte Carlo simulation

    SciTech Connect

    Moucka, Filip; Bratko, Dusan Luzar, Alenka

    2015-03-28

    Using a newly developed grand canonical Monte Carlo approach based on fractional exchanges of dissolved ions and water molecules, we studied equilibrium partitioning of both components between laterally extended apolar confinements and surrounding electrolyte solution. Accurate calculations of the Hamiltonian and tensorial pressure components at anisotropic conditions in the pore required the development of a novel algorithm for a self-consistent correction of nonelectrostatic cut-off effects. At pore widths above the kinetic threshold to capillary evaporation, the molality of the salt inside the confinement grows in parallel with that of the bulk phase, but presents a nonuniform width-dependence, being depleted at some and elevated at other separations. The presence of the salt enhances the layered structure in the slit and lengthens the range of inter-wall pressure exerted by the metastable liquid. Solvation pressure becomes increasingly repulsive with growing salt molality in the surrounding bath. Depending on the sign of the excess molality in the pore, the wetting free energy of pore walls is either increased or decreased by the presence of the salt. Because of simultaneous rise in the solution surface tension, which increases the free-energy cost of vapor nucleation, the rise in the apparent hydrophobicity of the walls has not been shown to enhance the volatility of the metastable liquid in the pores.

  14. Electrolyte pore/solution partitioning by expanded grand canonical ensemble Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Moucka, Filip; Bratko, Dusan; Luzar, Alenka

    2015-03-01

    Using a newly developed grand canonical Monte Carlo approach based on fractional exchanges of dissolved ions and water molecules, we studied equilibrium partitioning of both components between laterally extended apolar confinements and surrounding electrolyte solution. Accurate calculations of the Hamiltonian and tensorial pressure components at anisotropic conditions in the pore required the development of a novel algorithm for a self-consistent correction of nonelectrostatic cut-off effects. At pore widths above the kinetic threshold to capillary evaporation, the molality of the salt inside the confinement grows in parallel with that of the bulk phase, but presents a nonuniform width-dependence, being depleted at some and elevated at other separations. The presence of the salt enhances the layered structure in the slit and lengthens the range of inter-wall pressure exerted by the metastable liquid. Solvation pressure becomes increasingly repulsive with growing salt molality in the surrounding bath. Depending on the sign of the excess molality in the pore, the wetting free energy of pore walls is either increased or decreased by the presence of the salt. Because of simultaneous rise in the solution surface tension, which increases the free-energy cost of vapor nucleation, the rise in the apparent hydrophobicity of the walls has not been shown to enhance the volatility of the metastable liquid in the pores.

  15. Rapid analysis of acid in etching and pickling solutions

    SciTech Connect

    Tumbina, V.P.; Chinokalov, V.Ya.

    1995-02-01

    A computational method for determining sulfuric and hydrochloric acids in two-component etching solutions has been proposed. The method makes use of linear relationships, assuming that the sum of free and bound acid in solution remains constant.

  16. Reactive solute transport in acidic streams

    USGS Publications Warehouse

    Broshears, R.E.

    1996-01-01

    Spatial and temporal profiles of Ph and concentrations of toxic metals in streams affected by acid mine drainage are the result of the interplay of physical and biogeochemical processes. This paper describes a reactive solute transport model that provides a physically and thermodynamically quantitative interpretation of these profiles. The model combines a transport module that includes advection-dispersion and transient storage with a geochemical speciation module based on MINTEQA2. Input to the model includes stream hydrologic properties derived from tracer-dilution experiments, headwater and lateral inflow concentrations analyzed in field samples, and a thermodynamic database. Simulations reproduced the general features of steady-state patterns of observed pH and concentrations of aluminum and sulfate in St. Kevin Gulch, an acid mine drainage stream near Leadville, Colorado. These patterns were altered temporarily by injection of sodium carbonate into the stream. A transient simulation reproduced the observed effects of the base injection.

  17. Surface charge microscopy: novel technique for mapping charge-mosaic surfaces in electrolyte solutions.

    PubMed

    Yin, Xihui; Drelich, Jaroslaw

    2008-08-01

    The effective surface potential, called the zeta potential, is commonly determined from electrophoretic mobility measurements for particles moving in a solution in response to an electric field applied between two electrodes. The situation can be reversed, with the solution being forced to flow through a plug of packed particles, and the streaming potential of the particles can be calculated. A significant limitation of these electrokinetic measurements is that only an average value of the zeta potential/streaming potential is measured--regardless of whether the surface charge distribution is homogeneous or otherwise. However, in real-world situations, nearly all solids (and liquids) of technological significance exhibit surface heterogeneities. To detect heterogeneities in surface charge, analytical tools which provide accurate and spatially resolved information about the material surface potential--particularly at microscopic and submicroscopic resolutions--are needed. In this study, atomic force microscopy (AFM) was used to measure the surface interaction forces between a silicon nitride AFM cantilever and a multiphase volcanic rock. The experiments were conducted in electrolyte solutions with different ionic strengths and pH values. The colloidal force measurements were carried out stepwise across the boundary between adjacent phases. At each location, the force-distance curves were recorded. Surface charge densities were then calculated by fitting the experimental data with a DLVO theoretical model. Significant differences between the surface charge densities of the two phases and gradual transitions in the surface charge density at the interface were observed. It is demonstrated that this novel technique can be applied to examine one- and two-dimensional distributions of the surface potential. PMID:18620435

  18. Electrolyte for lead plate storage battery

    SciTech Connect

    Burke, D.

    1981-01-13

    An electrolyte for lead plate storage battery is disclosed comprising selenic acid (H/sub 2/SO/sub 4/) in aqueous solution at concentrations ranging from approximately 0.3 grams to approximately 4.0 grams of selenic acid per liter of electrolyte; the preferred embodiment of said electrolyte containing additional material selected from the group consisting of ferrous sulfate (FeSO/sub 4/) at concentrations ranging from approximately 0.1 grams to approximately 8.0 grams per liter of electrolyte, sodium chloride (NaCl) at concentrations ranging from approximately 0.1 grams to approximately 4.0 grams per liter of electrolyte, and manganous sulfate (MnSO/sub 4/) at concentrations ranging from approximately 005 grams to approximately 0.1 grams per liter of electrolyte.

  19. Separation of ions in acidic solution by capillary electrophoresis

    SciTech Connect

    Thornton, M.

    1997-10-08

    Capillary electrophoresis (CE) is an effective method for separating ionic species according to differences in their electrophoretic mobilities. CE separations of amino acids by direct detection are difficult due to their similar electrophoretic mobilities and low absorbances. However, native amino acids can be separated by CE as cations at a low pH by adding an alkanesulfonic acid to the electrolyte carrier which imparts selectivity to the system. Derivatization is unnecessary when direct UV detection is used at 185 nm. Simultaneous speciation of metal cations such as vanadium (IV) and vanadium (V) can easily be performed without complexation prior to analysis. An indirect UV detection scheme for acidic conditions was also developed using guanidine as the background carrier electrolyte (BCE) for the indirect detection of metal cations. Three chapters have been removed for separate processing. This report contains introductory material, references, and general conclusions. 80 refs.

  20. Base-acid hybrid water electrolysis.

    PubMed

    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

  1. Ion Pairing and Counterion Condensation in Aqueous Electrolyte and Poly-electrolyte Solutions: Insights from Molecular Simulation

    SciTech Connect

    Chialvo, Ariel A; Simonson, J Michael {Mike}

    2007-01-01

    We discuss the molecular-based study of ion-pair formation in LiCl aqueous solutions and its implications on the interpretation of the raw data from neutron diffraction with isotopic substitution experiments, the counterion condensation in aqueous polyelectrolyte solutions comprising short-chain lithium poly-styrene sulfonate (Li{sup +}-PSS{sup -}), as well as their interplay leading to the occurrence of 'like-charge' attractive interactions in the presence of salts of polyvalent counterions.

  2. American Society of Nephrology Quiz and Questionnaire 2014: Acid-Base and Electrolyte Disorders

    PubMed Central

    2015-01-01

    The Nephrology Quiz and Questionnaire remains an extremely popular session for attendees of the Annual Kidney Week Meeting of the American Society of Nephrology. Once again, in 2014 the conference hall was overflowing with audience members and eager quiz participants. Topics covered by the expert discussants included electrolyte and acid-base disorders, glomerular disease, ESRD/dialysis, and transplantation. Complex cases from each of these categories along with single-best-answer questions were prepared and submitted by the panel of experts. Before the meeting, program directors of United States nephrology training programs and nephrology fellows answered the questions using an Internet-based questionnaire. During the live session, members of the audience tested their knowledge and judgment on a series of case-oriented questions prepared and discussed by the experts. They compared their answers in real time using audience response devices with the answers of the nephrology fellows and training program directors. The correct and incorrect answers were then discussed after the audience responses and the results of the questionnaire were displayed. As always, the audience, lecturers, and moderators enjoyed this educational session. This article recapitulates the acid-base and electrolyte disorders portion of the session and reproduces its educational value for the readers of the Clinical Journal of the American Society of Nephrology. Enjoy the clinical cases and expert discussions. PMID:25617429

  3. American Society of Nephrology quiz and questionnaire 2014: acid-base and electrolyte disorders.

    PubMed

    Rosner, Mitchell H; Perazella, Mark A; Choi, Michael J

    2015-03-01

    The Nephrology Quiz and Questionnaire remains an extremely popular session for attendees of the Annual Kidney Week Meeting of the American Society of Nephrology. Once again, in 2014 the conference hall was overflowing with audience members and eager quiz participants. Topics covered by the expert discussants included electrolyte and acid-base disorders, glomerular disease, ESRD/dialysis, and transplantation. Complex cases from each of these categories along with single-best-answer questions were prepared and submitted by the panel of experts. Before the meeting, program directors of United States nephrology training programs and nephrology fellows answered the questions using an Internet-based questionnaire. During the live session, members of the audience tested their knowledge and judgment on a series of case-oriented questions prepared and discussed by the experts. They compared their answers in real time using audience response devices with the answers of the nephrology fellows and training program directors. The correct and incorrect answers were then discussed after the audience responses and the results of the questionnaire were displayed. As always, the audience, lecturers, and moderators enjoyed this educational session. This article recapitulates the acid-base and electrolyte disorders portion of the session and reproduces its educational value for the readers of the Clinical Journal of the American Society of Nephrology. Enjoy the clinical cases and expert discussions. PMID:25617429

  4. Process for the extraction of strontium from acidic solutions

    DOEpatents

    Horwitz, E. Philip; Dietz, Mark L.

    1994-01-01

    The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid.

  5. Process for the extraction of strontium from acidic solutions

    DOEpatents

    Horwitz, E.P.; Dietz, M.L.

    1993-01-01

    The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid.

  6. Process for the extraction of strontium from acidic solutions

    DOEpatents

    Horwitz, E.P.; Dietz, M.L.

    1994-09-06

    The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid. 4 figs.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Electrolyte Gated Transistors based on Solution Processed Mesoporous Tungsten Trioxide Thin Films

    NASA Astrophysics Data System (ADS)

    Santato, Clara; Isik, Dilek; Cicoira, Fabio

    2012-02-01

    Tungsten trioxide (WO3) is an important material for electrochromic displays, gas sensors, and photoelectrochemical cells. Despite intensive research efforts, the charge transport properties of nanostructured WO3 films, as well as of other metal oxide films, are still largely undiscovered. Electrolyte gating provides a powerful platform to study the charge transport properties of nanostructured WO3 films permitting to achieve high charge density regimes. In turn, this opens the possibility to improve the film transport properties for a wide range of applications. Here we report on electrolyte gated transistors making use of WO3 films as the semiconductor and H2SO4(aq) 1M as the gate dielectric. WO3 films, prepared by sol-gel method, were deposited on source and drain patterned ITO substrates. The liquid electrolyte was confined using a PDMS well. Atomic force microscopy and scanning electron microscopy images show a mesoporous film structure where the electrolyte can easily penetrate. The mesoporous structure permits an efficient electrolyte gating compared to bulk WO3 films because of the higher surface available for electrical double layers, which are the underpinning of the electrolyte gating. Upon application of gate bias in the 0-1 V range, with an applied drain voltage ranging between 0-1 V, we were able to tune the conductivity in the WO3 transistor channel: electrolyte gating of the films led to clear transistor behaviour. Electrolyte gating of WO3 electrochromism is presently under investigation.

  9. Containment of nitric acid solutions of Plutonium-238

    NASA Astrophysics Data System (ADS)

    Reimus, M. A. H.; Silver, G. L.; Pansoy-Hjelvik, L.; Ramsey, K. B.

    1999-01-01

    The corrosion of various metals that could be used to contain nitric acid solutions of Pu-238 has been studied. Tantalum and tantalum/2.5% tungsten resisted the test solvent better than 304L stainless steel and several INCONEL alloys. The solvent used to imitate nitric acid solutions of Pu-238 contained 70% nitric acid, hydrofluoric acid, and ammonium hexanitratocerate.

  10. Variations in surface characteristics and corrosion behaviour of metal brackets and wires in different electrolyte solutions.

    PubMed

    Kao, Chia-Tze; Huang, Tsui-Hsien

    2010-10-01

    The aim of this study was to assess the surface characteristics and to compare the corrosion potential of metal brackets and wires in environments containing different media. Four brands of metal brackets and two types of orthodontic wires [stainless steel and nickel-titanium (NiTi)] were investigated. An electrochemical assay was used to compare the corrosion potential (V) of the brackets and wires in different electrolyte media at 37°C. The test media were acidulated sodium fluoride (NaF) and pH 4 and pH 6 artificial saliva solutions. The data were analysed using analysis of variance with a predetermined significance level of α = 0.05. Scanning electron microscopy (SEM) was used to observe surface defects and corrosion. The results of the potentiodynamic curve showed that most brands of metal brackets were easily corroded in the NaF and pH 4 environments, while the NiTi and stainless steel wires were easily corroded in the pH 4 artificial saliva. SEM observations showed that defects or pitting corrosion occurred on the surfaces of the brackets and wires in all tested media. PMID:20139132

  11. Atomically resolved three-dimensional structures of electrolyte aqueous solutions near a solid surface

    PubMed Central

    Martin-Jimenez, Daniel; Chacon, Enrique; Tarazona, Pedro; Garcia, Ricardo

    2016-01-01

    Interfacial liquid layers play a central role in a variety of phenomena ranging from friction to molecular recognition. Liquids near a solid surface form an interfacial layer where the molecular structure is different from that of the bulk. Here we report atomic resolution three-dimensional images of electrolyte solutions near a mica surface that demonstrate the existence of three types of interfacial structures. At low concentrations (0.01–1 M), cations are adsorbed onto the mica. The cation layer is topped by a few hydration layers. At higher concentrations, the interfacial layer extends several nanometres into the liquid. It involves the alternation of cation and anion planes. Fluid Density Functional calculations show that water molecules are a critical factor for stabilizing the structure of the interfacial layer. The interfacial layer stabilizes a crystal-like structure compatible with liquid-like ion and solvent mobilities. At saturation, some ions precipitate and small crystals are formed on the mica. PMID:27416784

  12. Modeling of electro-osmosis of dilute electrolyte solutions in silica microporous media

    NASA Astrophysics Data System (ADS)

    Wang, Moran; Kang, Qinjun; Viswanathan, Hari; Robinson, Bruce A.

    2010-10-01

    Physicochemical transport due to electro-osmosis of dilute electrolyte solutions (<1 × 10-3 mol/L) through microporous media with granular random microstructures has been modeled in this work by our three-step numerical framework. First, the three-dimensional microstructures of porous media are reproduced by a random generation growth method. Second, the effects of chemical adsorption and electrical dissociation at the solid-liquid interfaces are modeled to determine the electrical boundary conditions, which vary with the ionic concentration, pH, and temperature. Finally, the nonlinear governing equations for electrokinetic transport are solved using a highly efficient lattice Poisson-Boltzmann algorithm. The simulation results indicate that the electro-osmotic permeability through the granular microporous media increases monotonically with the porosity, ionic concentration, pH, and temperature. When the surface electric potential is higher than about -50 mV, the electro-osmotic permeability exponentially increases with the electric potential. The electro-osmotic permeability increases with the bulk ionic concentration even though the surface zeta potential decreases correspondingly, which deviates from the conclusions based on the thin layer model. The electro-osmotic permeability increases exponentially with pH and linearly with temperature. The present modeling results improve our understanding of hydrodynamic and electrokinetic transport in geophysical systems and help guide the design of porous electrodes in microenergy systems.

  13. Nanobubble clusters of dissolved gas in aqueous solutions of electrolyte. II. Theoretical interpretation

    NASA Astrophysics Data System (ADS)

    Bunkin, N. F.; Shkirin, A. V.

    2012-08-01

    A quantitative model of ion-stabilized gas bubbles is suggested. Charging the bubbles by the ions, which are capable of adsorption, and the screening by a cloud of counter-ions, which are less absorptable, is modeled. It is shown that, subject to the charge of bubble, two regimes of such screening can be realized. For low-charged bubbles, the screening is described in the framework of the known linearized Debye-Huckel approach, when the sign of the counter-ion cloud is preserved everywhere in the liquid, whereas at large charge this sign is changed at some distance from the bubble surface. This effect provides the mechanism for the emergence of two types of compound particles having the opposite polarity, which leads to the aggregation of such compound particles into fractal clusters. Based on experimental data, arguments in favor of the existence of the clusters composed of the ion-stabilized bubbles in aqueous electrolyte solutions are advanced. This paper provides theoretical grounds for the experimental results presented in the previous paper (part I) published in this journal.

  14. Atomically resolved three-dimensional structures of electrolyte aqueous solutions near a solid surface.

    PubMed

    Martin-Jimenez, Daniel; Chacon, Enrique; Tarazona, Pedro; Garcia, Ricardo

    2016-01-01

    Interfacial liquid layers play a central role in a variety of phenomena ranging from friction to molecular recognition. Liquids near a solid surface form an interfacial layer where the molecular structure is different from that of the bulk. Here we report atomic resolution three-dimensional images of electrolyte solutions near a mica surface that demonstrate the existence of three types of interfacial structures. At low concentrations (0.01-1 M), cations are adsorbed onto the mica. The cation layer is topped by a few hydration layers. At higher concentrations, the interfacial layer extends several nanometres into the liquid. It involves the alternation of cation and anion planes. Fluid Density Functional calculations show that water molecules are a critical factor for stabilizing the structure of the interfacial layer. The interfacial layer stabilizes a crystal-like structure compatible with liquid-like ion and solvent mobilities. At saturation, some ions precipitate and small crystals are formed on the mica. PMID:27416784

  15. Copper-Sulfate Pentahydrate as a Product of the Waste Sulfuric Acid Solution Treatment

    NASA Astrophysics Data System (ADS)

    Marković, Radmila; Stevanović, Jasmina; Avramović, Ljiljana; Nedeljković, Dragutin; Jugović, Branimir; Stajić-Trošić, Jasna; Gvozdenović, Milica

    2012-12-01

    The aim of this study is synthesis of copper-sulfate pentahydrate from the waste sulfuric acid solution-mother liquor generated during the regeneration process of copper bleed solution. Copper is removed from the mother liquor solution in the process of the electrolytic treatment using the insoluble lead anodes alloyed with 6 mass pct of antimony on the industrial-scale equipment. As the result of the decopperization process, copper is removed in the form of the cathode sludge and is precipitated at the bottom of the electrolytic cell. By this procedure, the content of copper could be reduced to the 20 mass pct of the initial value. Chemical characterization of the sludge has shown that it contains about 90 mass pct of copper. During the decopperization process, the very strong poison, arsine, can be formed, and the process is in that case terminated. The copper leaching degree of 82 mass pct is obtained using H2SO4 aqueous solution with the oxygen addition during the cathode sludge chemical treatment at 80 °C ± 5 °C. Obtained copper salt satisfies the requirements of the Serbian Standard for Pesticide, SRPS H.P1. 058. Therefore, the treatment of waste sulfuric acid solutions is of great economic and environmental interest.

  16. Electrolyte-free milk protein solution influences sodium and fluid retention in rats.

    PubMed

    Ishihara, Kengo; Kato, Yoshiho; Usami, Ayako; Yamada, Mari; Yamamura, Asuka; Fushiki, Tohru; Seyama, Yousuke

    2013-01-01

    Milk is an effective post-exercise rehydration drink that maintains the net positive fluid balance. However, it is unclear which components are responsible for this effect. We assessed the effect of milk protein solution (MPS) obtained by dialysis on body fluid retention. Milk, MPS, milk electrolyte solution (MES), sports drink and water were administered to male Wistar rats at a dose of 6 ml/rat after treadmill exercise. Total body fluid retention was assessed by urine volume 4 h after administration of hydrating liquids. The rate of gastric emptying was evaluated by a tracer method using (13)C-labelled acetate. Plasma osmolality, Na and K levels, and urinary Na and K were measured by HPLC and osmometry, respectively. The gastric emptying rate was not delayed by MPS. During 4 h of rehydration, cumulative urine volumes differed significantly between treatment groups (P < 0·05) with 4·9, 2·2 and 3·4 ml from water-, milk- and MPS-fed rats, respectively. Thus, MPS elicited 50 % of the total body fluid retention of milk. Plasma aldosterone levels were significantly higher in MPS- and milk-fed rats compared with water-fed rats. Plasma osmolality was maintained at higher levels in MPS-fed rats than in water- and MES-fed rats (P < 0·05). Cumulative urine Na excretion was also suppressed in the milk- and MPS-fed groups compared with the MES-fed group. Our results demonstrate that MPS obtained by dialysis clearly affects net body water balance without affecting gastric emptying after exercise. This effect was attributed to retention of Na and water, and maintenance of plasma osmolality. PMID:25191594

  17. Lysozyme Net Charge and Ion Binding in Concentrated Aqueous Electrolyte Solutions

    SciTech Connect

    Kuehner, Daniel E.; Engmann, Jan; Fergg, Florian; Wernick, Meredith; Blanch, Harvey W.; Prausnitz, John M.

    1999-02-01

    Hydrogen-ion titrations were conducted for hen-egg-white lysozyme in solutions of potassium chloride, over the range of pH 2.5 - 11.5 and for ionic strengths to 2. 0 M. The dependence of lysozyme's net proton charge, zP' on pH and ionic-strength in potassium-chloride solution is measured. From the ionic-strength dependence of zP' interactions of lysozynie with potassium and chloride ions are calculated using the molecular-thennodynamic theory of Fraaije and Lyklema 1. Lysozyme interacts preferentially with up to 12 chloride ions at pH 2.5. The observed dependence of ion-protein interactions on pH and ionic strength is explained in terms of electricdouble-layer theory. New experimental pKa data are reported for eleven ammo acids in potassium-chloride solutions of ionic strength to 3.0 M.

  18. Lysozyme net charge and ion binding in concentrated aqueous electrolyte solutions

    SciTech Connect

    Kuehner, Daniel E.; Engmann, Jan; Fergg, Florian; Wernick, Meredith; Blanch, Harvey W.; Prausnitz, John M.

    1999-02-01

    Hydrogen-ion titrations were conducted for hen-egg-white lysozyme in solutions of potassium chloride over the range pH 2.5--11.5 and for ionic strengths to 2.0 M. The dependence of lysozyme`s net proton charge, z{sub p}, on pH and ionic strength in potassium chloride solution is measured. From the ionic-strength dependence of z{sub p}, interactions of lysozyme with potassium and chloride ions are calculated using the molecular-thermodynamic theory of Fraaije and Lyklema. Lysozyme interacts preferentially with up to 12 chloride ions at pH 2.5. The observed dependence of ion-protein interactions on pH and ionic strength is explained in terms of electric-double-layer theory. New experimental pK{sub a} data are reported for 11 amino acids in potassium chloride solutions of ionic strength to 3.0 M.

  19. Irreversible morphological changes of a graphite negative-electrode at high potentials in LiPF6-based electrolyte solution.

    PubMed

    Domi, Yasuhiro; Doi, Takayuki; Tsubouchi, Shigetaka; Yamanaka, Toshiro; Abe, Takeshi; Ogumi, Zempachi

    2016-08-10

    The degradation mechanism of a graphite negative-electrode in LiPF6-based electrolyte solution was investigated using the basal plane of highly oriented pyrolytic graphite (HOPG) as a model electrode. Changes in the surface morphology were observed by in situ atomic force microscopy. In the initial cathodic scan, a number of pits appeared at around 1.75 V vs. Li(+)/Li, and fine particles formed on the terrace of the HOPG basal plane at about 1.5 V vs. Li(+)/Li. The fine particles were characterized by spectroscopic analysis, such as X-ray photoelectron spectroscopy and attenuated total reflection Fourier transform infrared spectroscopy. We added one of the components to LiClO4-based electrolyte solution, and successfully reproduced the formation of pits and fine particles on the basal plane of HOPG. Based on these results, the formation mechanisms of pits and fine particle layers were proposed. PMID:27465798

  20. Vapor pressure measurements on non-aqueous electrolyte solutions. Part 2. Tetraalkylammonium salts in methanol. Activity coefficients of various 1-1 electrolytes at high concentrations

    SciTech Connect

    Barthel, J.; Lauermann, G.; Neueder, R.

    1986-10-01

    Precise vapor pressure data for solutions of Et/sub 4/NBr, Bu/sub 4/NBr, Bu/sub 4/Nl, Bu/sub 4/NClO/sub 4/, and Am/sub 4/NBr in methanol at 25/sup 0/C in the concentration range 0.04 < m(mol-(kg of solvent)/sup -1/) < 1.6 are communicated and discussed. Polynomials in molalities are given which may be used for calculating precise vapor pressure depressions of these solutions. Osmotic coefficients are calculated by taking into account the second virial coefficient of methanol vapor. Discussion of the data at low concentrations is based on the chemical model of electrolyte solutions taking into account non-coulombic interactions; ion-pair association constants are compared to those of conductance measurements. Pitzer equations are used to reproduce osmotic and activity coefficient at high concentrations; the set of Pitzer parameters b = 3.2, ..cap alpha../sub 1/ = 2.0 and ..cap alpha../sub 2/ = 20.0 is proposed for methanol solutions.

  1. [Adverse effects of drugs in intensive care units: analysis of the administration of electrolyte solutions and antibiotics].

    PubMed

    Manenti, S; Chaves, A B; Leopoldino, R S; Padilha, K G

    1998-12-01

    The aims of this study were: 1) to verify the incidence of adverse occurrences (AOs) with medication related to the time of electrolyte solutions infusion and the frequency of doses of antibiotics prescribed and administered to the patients; 2) to characterize the nature of those occurrences. The study was developed in two ICUs of a general hospital of São Paulo City. The population was composed by 51 patients that were in the ICUs in August of 1996. Sixty percent of the patients were older than 60 years, 58.8% were women, 49.1% remained in ICU from 1 to 4 days and 41.2% went to the Intermediate Care Units after ICU. Regarding the incidence of AOs related to the time of administration of the electrolyte solutions and the frequency of doses of antibiotics the non execution of the patient's medical prescriptions was verified in 76.3% and 38.8% respectively. The largest frequency of irregularities with the electrolyte solutions (60.2%) was the infusion faster than the prescribed time followed by the reduction of the number of doses of antibiotics administered. Taking these into consideration we have to invest in preventive measures to reduce those occurrences. PMID:10614484

  2. Effects of background electrolytes and ionic strength on enrichment of Cd(II) ions with magnetic graphene oxide-supported sulfanilic acid.

    PubMed

    Hu, Xin-jiang; Liu, Yun-guo; Zeng, Guang-ming; You, Shao-hong; Wang, Hui; Hu, Xi; Guo, Yi-ming; Tan, Xiao-fei; Guo, Fang-ying

    2014-12-01

    To elucidate the influence mechanisms of background electrolytes and ionic strength on Cd(II) removal, the adsorption of Cd(II) onto magnetic graphene oxide-supported sulfanilic acid (MGO-SA) in aqueous solutions containing different types and concentrations of background electrolytes was studied. The results indicate that Cd(II) adsorption was strongly dependent on pH and could be strongly affected by background electrolytes and ionic strength. The Cd(II) removal was decreased with the presence of background electrolyte cations (Na(+), K(+), Ca(2+), Mg(2+), Mn(2+), Zn(2+), and Ni(2+)), and the divalent cations exerted more obvious influences on the Cd(II) uptake than the monovalent cations at pH 6. Both Cl(-) and NO3(-) had negative effects on Cd(II) adsorption because they can form water-soluble metal-anion complexes with Cd(II) ions. The presence of 0.01molL(-1) Na3PO4 reduced the removal percentage of Cd(II) at pH<5 but extremely enhanced the Cd(II) removal when the pH>5. The Cd(II) adsorption was sensitive to changes in the concentration of NaCl, NaNO3, NaClO4, and Na3PO4. Besides, the adsorption isotherm of Cd(II) onto MGO-SA could be well described by the Freundlich model and was also influenced by the type of background electrolyte ions and the ionic strength. PMID:25238326

  3. Failure mechanism of layered lithium-rich oxide/graphite cell and its solution by using electrolyte additive

    NASA Astrophysics Data System (ADS)

    Zhu, Yunmin; Luo, Xueyi; Xu, Mengqing; Zhang, Liping; Yu, Le; Fan, Weizhen; Li, Weishan

    2016-06-01

    We report a failure mechanism of layered lithium-rich oxide/graphite cell and a solution to this failure. Charge/discharge tests demonstrate that Li1.2Mn0.54Ni0.13Co0.13O2/graphite full cell fails when it is performed with cycling and this issue can be solved effectively by using an electrolyte additive, tris (trimethylsilyl) phosphite (TMSPi). Further cycling tests on Li/Li1.2Mn0.54Ni0.13Co0.13O2 and Li/graphite half-cells and physical characterizations on the cycled cathode indicate that this failure involves the increased HF concentration and the subsequent corrosion for aluminum current collector of cathode due to the electrolyte decomposition during cycling. TMSPi contributes to the formation of a protective interphase on cathode due to its preferential oxidation compared with the base electrolyte, which suppresses the electrolyte decomposition and the HF formation, preventing aluminum current collector from corrosion.

  4. Investigation of electrolyte wetting in lithium ion batteries: Effects of electrode pore structures and solution

    NASA Astrophysics Data System (ADS)

    Sheng, Yangping

    Beside natural source energy carriers such as petroleum, coal and natural gas, the lithium ion battery is a promising man-made energy carrier for the future. This is a similar process evolved from horse-powered era to engine driven age. There are still a lot of challenges ahead like low energy density, low rate performance, aging problems, high cost and safety etc. In lithium ion batteries, investigation about manufacturing process is as important as the development of material. The manufacturing of lithium ion battery, including production process (slurry making, coating, drying etc.), and post-production (slitting, calendering etc.) is also complicated and critical to the overall performance of the battery. It includes matching the capacity of anode and cathode materials, trial-and-error investigation of thickness, porosity, active material and additive loading, detailed microscopic models to understand, optimize, and design these systems by changing one or a few parameters at a time. In the manufacturing, one of the most important principles is to ensure good wetting properties between porous solid electrodes and liquid electrolyte. Besides the material surface properties, it is the process of electrolyte transporting to fill the pores in the electrode after injection is less noticed in academic, where only 2-3 drops of electrolyte are needed for lab coin cell level. In industry, the importance of electrolyte transport is well known and it is considered as part of electrolyte wetting (or initial wetting in some situations). In consideration of practical usage term, electrolyte wetting is adopted to use in this dissertation for electrolyte transporting process, although the surface chemistry about wetting is not covered. An in-depth investigation about electrolyte wetting is still missing, although it has significant effects in manufacturing. The electrolyte wetting is determined by properties of electrolyte and electrode microstructure. Currently, only viscosity

  5. A cerium-lead redox flow battery system employing supporting electrolyte of methanesulfonic acid

    NASA Astrophysics Data System (ADS)

    Na, Zhaolin; Xu, Shengnan; Yin, Dongming; Wang, Limin

    2015-11-01

    A novel cerium-lead redox flow battery (RFB) employing Ce(IV)/Ce(III) and Pb(II)/Pb redox couples in the supporting electrolyte of methanesulfonic acid (MSA) is developed and preliminarily investigated. The RFB requires no additional catalyst and uses kinetically favorable reactions between low-cost reactants, and provides a desirable discharge voltage of approximately 1.7 V, with high average coulombic efficiency (CE) of 92% and energy efficiency (EE) of 86% over 800 cycles at 298 K. Stable cycling with an acceptable performance is achieved for a board operating temperature range of 253 K-313 K. The excellent performance obtained from the preliminary study suggests that the cerium-lead RFB promises to be applicable to large-scale energy storage for electricity grids.

  6. Electrolyte depletion control laws for lead-acid battery discharge optimisation

    NASA Astrophysics Data System (ADS)

    Tenno, R.; Nefedov, E.

    2014-12-01

    The technique described in this paper balances the power and energy withdrawn from a battery in galvanostatic discharge control that aims for stabilisation of the electrolyte concentration above the depletion level. This aim is achieved with relatively simple proportional feedback controls that are exponentially stabilising controls for a simple diffusion process that is the core part of battery processes. Although the full mapping of the proposed controls to state is rather complex, it has shown that the transformation works. In practice, these controls can be approximated either with the integrated past controls or with a simple exponential function that depends on a few parameters adjusted to the electrochemical processes in a battery under consideration. The battery control is tested in simulation on a detailed model developed for a lead-acid electrochemical cell.

  7. Acid electrolyte fuel cell technology program. [for application to the space shuttle orbiter

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The development of an acid electrolyte fuel cell was investigated to provide a cost effective electrical power system for the space shuttle orbiter. Previous investigation showed the life capability of the fuel cell was improved by proper prehumidification of the reactant gases. Breadboard models were developed which incorporate reactant prehumidification and have a life duration time of 2000 hours. Fuel cell performance was found to be invariant with cell life, and reactant consumption was unchanged from start to end of life. Satisfactory start and stop procedures are demonstrated along with scale-up capabilities for the number of cells in a stack, and for cell active areas. Safety design features, which operate to isolate the affected module from the remainder of the system, to eliminate single point failure modes from affecting the entire electrical power system are included.

  8. Improved fabrication of electrolytic capacitors

    NASA Technical Reports Server (NTRS)

    Gamari, F. J.; Moresi, J. L.

    1975-01-01

    After processing parts for assembly, insulative cup is fitted to bottom of can, then electrolytic solution consisting of white sulfuric acid gel is inserted into can. Pellet is put in can and is fitted tightly into cup. Finally, bead weld is formed between can and header plug.

  9. Nitric acid uptake by sulfuric acid solutions under stratospheric conditions - Determination of Henry's Law solubility

    NASA Technical Reports Server (NTRS)

    Reihs, Christa M.; Golden, David M.; Tolbert, Margaret A.

    1990-01-01

    The uptake of nitric acid by sulfuric acid solutions representative of stratospheric particulate at low temperatures was measured to determine the solubility of nitric acid in sulfuric acid solutions as a function of H2SO4 concentration and solution temperature. Solubilities are reported for sulfuric acid solutions ranging from 58 to 87 wt pct H2SO4 over a temperature range from 188 to 240 K, showing that, in general, the solubility of nitric acid increases with decreasing sulfuric acid concentration and with decreasing temperature. The measured solubilities indicate that nitric acid in the global stratosphere will be found predominantly in the gas phase.

  10. Thermodynamic quantities of surface formation of aqueous electrolyte solutions. VI. Comparison with typical nonelectrolytes, sucrose and glucose.

    PubMed

    Matubayasi, Norihiro; Nishiyama, Ai

    2006-06-15

    To demonstrate an important distinction between the electrolytes and nonelectrolytes, surface tension of aqueous solutions of typical nonelectrolytes, sucrose and glucose, was measured as a function of temperature and concentration. The presence of sucrose or glucose molecules in the surface region affects the surface tension in the same way as the presence of an ion does. There is, however, a difference in the temperature coefficient of the surface tension between typical nonelectrolyte solutions, sucrose and glucose, and alkali halide solutions. The entropy of surface formation of sucrose and glucose solutions is the same as that of pure water, while that of alkali halide solutions decreases with concentration. The relation between this entropy change and the formation of electric double layers was discussed. PMID:16469326

  11. Development and Evaluation of a Multimedia e-Learning Resource for Electrolyte and Acid-Base Disorders

    ERIC Educational Resources Information Center

    Davids, Mogamat Razeen; Chikte, Usuf M. E.; Halperin, Mitchell L.

    2011-01-01

    This article reports on the development and evaluation of a Web-based application that provides instruction and hands-on practice in managing electrolyte and acid-base disorders. Our teaching approach, which focuses on concepts rather than details, encourages quantitative analysis and a logical problem-solving approach. Identifying any dangers to…

  12. Non-aqueous electrolytes for lithium ion batteries

    SciTech Connect

    Chen, Zonghai; Amine, Khalil

    2015-11-12

    The present invention is generally related to electrolytes containing anion receptor additives to enhance the power capability of lithium-ion batteries. The anion receptor of the present invention is a Lewis acid that can help to dissolve LiF in the passivation films of lithium-ion batteries. Accordingly, one aspect the invention provides electrolytes comprising a lithium salt; a polar aprotic solvent; and an anion receptor additive; and wherein the electrolyte solution is substantially non-aqueous. Further there are provided electrochemical devices employing the electrolyte and methods of making the electrolyte.

  13. Polarographic behavior of vanadium(V) in mixed mineral-acid-organic electrolytes

    SciTech Connect

    Kurbatov, D.I.; Egorochkin, V.M.

    1988-01-01

    Reducing vanadium(V) in phosphoric-acid-potassium citrate-EDTA solutions in order to develop its polarographic determination in iron-containing materials was studied. Polarography with triangular potential sweep was used. The reference electrode was a saturated calomel electrode linked to the test via a potassium chloride salt bridge. Working solutions were prepared with phosphoric acid solution. It was established that polarographic characteristics depend on solution pH. Experimental currents of the second cathodic and anodic wave as functions of potential scan rate in order to examine the kinetics and mechanism of vanadium(V) reduction under optimum conditions was also studied and found to be irreversible. Polarographic characteristics are tabulated.

  14. Effect of electrolyte volume on the acid dissolution of aluminum alloy 7075

    SciTech Connect

    McCafferty, E.

    1998-11-01

    Dissolution of aluminum alloy 7075 (UNS A97075) was studied using weight-loss measurements in a series of hydrochloric acid (HCl) solutions varying in concentration from 0.5 M to 2 M. The open-circuit reaction was observed to be first order in the hydrogen ion. In acid solutions having a fixed supply of hydrogen ions, corrosion of Al 7075 was arrested by depletion of that available supply. For a given initial acid molarity (M) and a given initial surface area, the total amount of corrosion (weight loss [G]) is given by G = 0.0101 V M, where V is the volume of solution. For a given set of conditions (initial acid concentration, initial surface area, and volume of solution), the time for cessation of the corrosion reaction as calculated from first-order reaction kinetics was in agreement with experimentally determined values. Two corrosion systems were discussed as possible applications involving cessation of a corrosion reaction in acid environments caused by depletion of the hydrogen ion supply.

  15. Chemical transformations of CO2 in trifluoroacetic acid solutions

    NASA Astrophysics Data System (ADS)

    Vishnetskaya, M. V.; Ivanova, M. S.; Svichkarev, O. M.; Budynina, E. M.; Mel'nikov, M. Ya.

    2013-05-01

    It is established that a conversion reaction of carbon dioxide takes place at room temperature and atmospheric pressure in aqueous solutions of trifluoroacetic acid (TFA), which leads to the formation of oxalic acid and heavier polymerized products.

  16. Modifications in interaction and structure of silica nanoparticle-BSA protein system in aqueous electrolyte solution

    NASA Astrophysics Data System (ADS)

    Yadav, Indresh; Aswal, V. K.; Kohlbrecher, J.

    2015-06-01

    SANS measurements have been carried out to examine the modifications in interaction and structure of anionic silica nanoparticle with anionic BSA protein in presence of an electrolyte. The phase behaviour of anionic silica nanoparticle and anionic BSA protein is governed by the protein induced depletion interaction between nanoparticles. Both nanoparticle and protein coexist individually at low protein concentrations as electrostatic repulsion dominates over the depletion interaction. However, depletion induced fractal aggregates of nanoparticles are formed at higher protein concentrations. These aggregates can be formed at much smaller protein concentration in presence of an electrolyte. We show that both the electrostatic (decrease) and depletion interaction (increase) are modified with an electrolyte. The range of the depletion interaction is found to be significantly larger than the electrostatic interaction.

  17. Reconstruction and dissolution of shape-controlled Pt nanoparticles in acidic electrolytes.

    PubMed

    Devivaraprasad, Ruttala; Kar, Tathagata; Chakraborty, Arup; Singh, Ramesh Kumar; Neergat, Manoj

    2016-04-20

    Shape-controlled nanoparticles are of utmost scientific and technological importance because of their facet-dependent physical and chemical properties. Under long-term electrochemical conditions, little is known about the stability and fate of these nanoparticles with selected exposed crystallographic orientations (facets) of high surface energy, while it is generally accepted that the surface area decreases. Therefore, the reconstruction and dissolution of platinum nanocubes (Pt-NCs), platinum cuboctahedral (Pt-CO) and platinum polycrystalline (Pt-PC) nanoparticles are investigated using voltammetry and in situ irreversible adsorption of Bi and Ge; the cleanliness of the Pt nanoparticles and the purity of the electrolyte solution are established with systematic voltammetric analysis in a H2SO4 electrolyte of different concentrations (0.01, 0.05, 0.5 and 1 M). The voltammetric results suggest that the {100} terrace sites undergo reconstruction/dissolution at a much higher rate relative to that of the {111} ordered bi-dimensional terrace sites and the reconstruction leads to the formation of {110}/{100} step sites. Therefore, the stability of the Pt-NCs is lower than that of the Pt-CO nanoparticles. The gradual decrease in the Hupd area on prolonged cycling in the lower potential range (0.06-0.6 and 0.06-0.8 V) is attributed to the accumulation of oxy-anions from the electrolyte on the Pt surface. Moreover, dissolution of highly energetic Pt sites also contributes to the reduction in the Hupd area, unlike that observed with low index Pt single crystal surfaces. On cycling to higher potential limits (1.0 and 1.2 V), the adsorbed anions are replaced with the oxygenated species or oxide; the protective oxide layer helps to stabilize the electrochemical surface area (ESA) of the Pt nanoparticles. With cycling, both Pt-NCs and Pt-CO eventually get converted to Pt-PC. These results are supported with cyclic voltammograms, irreversible adsorption of Bi and Ge, and HR

  18. Pretreatment of microcrystalline cellulose in organic electrolyte solutions for enzymatic hydrolysis

    PubMed Central

    2011-01-01

    Background Previous studies have shown that the crystalline structure of cellulose is negatively correlated with enzymatic digestibility, therefore, pretreatment is required to break down the highly ordered crystalline structure in cellulose, and to increase the porosity of its surface. In the present study, an organic electrolyte solution (OES) composed of an ionic liquid (1-allyl-3-methylimidazolium chloride ([AMIM]Cl)) and an organic solvent (dimethyl sulfoxide; DMSO) was prepared, and used to pretreat microcrystalline cellulose for subsequent enzymatic hydrolysis; to our knowledge, this is the first time that this method has been used. Results Microcrystalline cellulose (5 wt%) rapidly dispersed and then completely dissolved in an OES with a molar fraction of [AMIM]Cl per OES (χ [AMIM]Cl) of greater than or equal to 0.2 at 110°C within 10 minutes. The cellulose was regenerated from the OES by precipitation with hot water, and enzymatically hydrolyzed. As the χ [AMIM]Cl of the OES increased from 0.1 to 0.9, both the hydrolysis yield and initial hydrolysis rate of the regenerated cellulose also increased gradually. After treatment using OES with χ [AMIM]Cl of 0.7, the glucose yield (54.1%) was 7.2 times that of untreated cellulose. This promotion of hydrolysis yield was mainly due to the decrease in the degree of crystallinity (that is, the crystallinity index of cellulose I). Conclusions An OES of [AMIM]Cl and DMSO with χ [AMIM]Cl of 0.7 was chosen for cellulose pretreatment because it dissolved cellulose rapidly to achieve a high glucose yield (54.1%), which was only slightly lower than the value (59.6%) obtained using pure [AMIM]Cl. OES pretreatment is a cost-effective and environmentally friendly technique for hydrolysis, because it 1) uses the less expensive OES instead of pure ionic liquids, 2) shortens dissolution time, 3) requires lower energy for stirring and transporting, and 4) is recyclable. PMID:22099703

  19. Electrochemical determination of activation energies for methanol oxidation on polycrystalline platinum in acidic and alkaline electrolytes.

    PubMed

    Cohen, Jamie L; Volpe, David J; Abruña, Héctor D

    2007-01-01

    The oxidation pathways of methanol (MeOH) have been the subject of intense research due to its possible application as a liquid fuel in polyelectrolyte membrane (PEM) fuel cells. The design of improved catalysts for MeOH oxidation requires a deep understanding of these complex oxidation pathways. This paper will provide a discussion of the literature concerning the extensive research carried out in acidic and alkaline electrolytes. It will highlight techniques that have proven useful in the determination of product ratios, analysis of surface poisoning, anion adsorption, and oxide formation processes, in addition to the effects of temperature on the MeOH oxidation pathways at bulk polycrystalline platinum (Pt(poly)) electrodes. This discussion will provide a framework with which to begin the analysis of activation energy (E(a)) values. This kinetic parameter may prove useful in characterizing the rate-limiting step of the MeOH oxidation at an electrode surface. This paper will present a procedure for the determination of E(a) values for MeOH oxidation at a Pt(poly) electrode in acidic and alkaline media. Values from 24-76 kJ mol(-1) in acidic media and from 36-86 kJ mol(-1) in alkaline media were calculated and found to be a function of applied potential and direction of the potential sweep in a voltammetric experiment. Factors that influence the magnitude of the calculated E(a) include surface poisoning from MeOH oxidation intermediates, anion adsorption from the electrolyte, pH effects, and oxide formation processes. These factors are all potential, and temperature, dependent and must clearly be addressed when citing E(a) values in the literature. Comparison of E(a) values must be between systems of comparable electrochemical environment and at the same potential. E(a) values obtained on bulk Pt(poly), compared with other catalysts, may give insight into the superiority of other Pt-based catalysts for MeOH oxidation and lead to the development of new catalysts

  20. Excellent stability of a lithium-ion-conducting solid electrolyte upon reversible Li(+) /H(+) exchange in aqueous solutions.

    PubMed

    Ma, Cheng; Rangasamy, Ezhiylmurugan; Liang, Chengdu; Sakamoto, Jeffrey; More, Karren L; Chi, Miaofang

    2015-01-01

    Batteries with an aqueous catholyte and a Li metal anode have attracted interest owing to their exceptional energy density and high charge/discharge rate. The long-term operation of such batteries requires that the solid electrolyte separator between the anode and aqueous solutions must be compatible with Li and stable over a wide pH range. Unfortunately, no such compound has yet been reported. In this study, an excellent stability in neutral and strongly basic solutions was observed when using the cubic Li7 La3 Zr2 O12 garnet as a Li-stable solid electrolyte. The material underwent a Li(+) /H(+) exchange in aqueous solutions. Nevertheless, its structure remained unchanged even under a high exchange rate of 63.6 %. When treated with a 2 M LiOH solution, the Li(+) /H(+) exchange was reversed without any structural change. These observations suggest that cubic Li7 La3 Zr2 O12 is a promising candidate for the separator in aqueous lithium batteries. PMID:25331968

  1. Excellent stability of a lithium-ion-conducting solid electrolyte upon reversible Li+/H+ exchange in aqueous solutions

    DOE PAGESBeta

    Ma, Cheng; Rangasamy, Ezhiylmurugan; Liang, Chengdu; Sakamoto, Jeffrey; More, Karren Leslie; Chi, Miaofang

    2014-10-21

    Batteries with an aqueous catholyte and a Li metal anode have attracted interest owing to their exceptional energy density and high charge/discharge rate. The long-term operation of such batteries requires that the solid electrolyte separator between the anode and aqueous solutions must be compatible with Li and stable over a wide pH range. Unfortunately, no such compound has yet been reported. In this study, an excellent stability in neutral and strongly basic solutions was observed when using the cubic Li7La3Zr2O12 garnet as a Li-stable solid electrolyte. The material underwent a Li+/H+ exchange in aqueous solutions. Nevertheless, its structure remained unchangedmore » even under a high exchange rate of 63.6%. When treated with a 2 M LiOH solution, the Li+/H+ exchange was reversed without any structural change. Furthermore, these observations suggest that cubic Li7La3Zr2O12 is a promising candidate for the separator in aqueous lithium batteries.« less

  2. Evaluation of lead anode reactions in acid sulfate electrolytes. 1: Lead alloys with cobalt additives

    SciTech Connect

    Yu, P.; O`Keefe, T.J.

    1999-04-01

    Lead alloys, such as lead-calcium-tin and lead-silver, are the primary insoluble anodes used in the electrowinning of metals. While some difficulties are encountered in their use, there is no obvious replacement that is economically and technically competitive. Two of the specific problems with lead include decreased cathode purity due to incorporation from corrosion products and the relatively high overpotential which increases cell voltage. To gain an improved understanding of the fundamental behavior of lead anodes, the polarization behavior of six different alloys in sulfuric acid was evaluated. Some tests were also made with Co(II) in the acid sulfate electrolyte. Notable differences were found in the multiple activation-passivation cycles, stability, and relative activity for oxygen evolution for the alloys, and the relative trends in behavior were established. Electrochemical impedance spectroscopy studies were also conducted at selected potentials. Overall, the data show that the electrochemical response, particularly the degree of polarization for the oxygen evolution reaction, of the lead alloy anodes are dependent on the surface phases and structures present. The ability to depolarize the anode reaction using Co(II) was particularly sensitive to the lead composition.

  3. [Electrolyte and acid-base balance disorders in advanced chronic kidney disease].

    PubMed

    Alcázar Arroyo, R

    2008-01-01

    1. The kidneys are the key organs to maintain the balance of the different electrolytes in the body and the acid-base balance. Progressive loss of kidney function results in a number of adaptive and compensatory renal and extrarenal changes that allow homeostasis to be maintained with glomerular filtration rates in the range of 10-25 ml/min. With glomerular filtration rates below 10 ml/min, there are almost always abnormalites in the body's internal environment with clinical repercussions. 2. Water Balance Disorders: In advanced chronic kidney disease (CKD), the range of urine osmolality progressively approaches plasma osmolality and becomes isostenuric. This manifests clinically as symptoms of nocturia and polyuria, especially in tubulointerstitial kidney diseases. Water overload will result in hyponatremia and a decrease in water intake will lead to hypernatremia. Routine analyses of serum Na levels should be performed in all patients with advanced CKD (Strength of Recommendation C). Except in edematous states, a daily fluid intake of 1.5-2 liters should be recommended (Strength of Recommendation C). Hyponatremia does not usually occur with glomerular filtration rates above 10 ml/min (Strength of Recommendation B). If it occurs, an excessive intake of free water should be considered or nonosmotic release of vasopressin by stimuli such as pain, anesthetics, hypoxemia or hypovolemia, or the use of diuretics. Hypernatremia is less frequent than hyponatremia in CKD. It can occur because of the provision of hypertonic parenteral solutions, or more frequently as a consequence of osmotic diuresis due to inadequate water intake during intercurrent disease, or in some circumstance that limits access to water (obtundation, immobility). 3. Sodium Balance Disorders: In CKD, fractional excretion of sodium increases so that absolute sodium excretion is not modified until glomerular filtration rates below 15 ml/min (Strength of Recommendation B). Total body content of sodium is

  4. Two new frameworks of potassium saccharate obtained from acidic and alkaline solution

    SciTech Connect

    Lv, Yao-Kang; Feng, Yun-Long; Liu, Ji-Wei; Jiang, Zhan-Guo

    2011-05-15

    Two chiral K(I) complexes based on D-saccharic acid (H{sub 2}sac), [K(Hsac)]{sub n} (1) and [K{sub 2}(sac)]{sub n} (2) were obtained from acidic and alkaline solution. The 3D framework of 1 includes K(I) polyhedral rods and typical pairwise coaxial right- and left-handed helical chains, and displays binodal 6-connected pcu topology. 2 contains 2D polyhedral sheets consisting of left-handed helical chains, and generates 3D network with an unprecedented (7,11)-connected net. Cyclic voltammetry tests and charge-discharge tests indicate that the addition of complex 2 to the electrolyte could improve the electrochemical properties of the nickel hydroxide electrode. -- Graphical abstract: Two K(I) complexes based on D-saccharic acid (H{sub 2}sac), [K(Hsac)]{sub n} (1) and [K{sub 2}(sac)]{sub n} (2) were obtained and characterized. Electrochemical studies indicate the potential use of 2 in Ni-MH battery. Display Omitted highlights: > Two novel chiral K(I) frameworks based on D-saccharic acid were obtained. > The structure of 1 includes K(I) polyhedral rods and typical helical chains. > 2 contains 2D polyhedral sheets and generates an unprecedented (7,11)-connected net. > Addition of 2 to electrolyte could improve the nickel hydroxide electrode's property.

  5. Equilibria Between Cell Membranes and Electrolyte Solution: Effect of Fatal Accidental Hypothermia.

    PubMed

    Petelska, Aneta D; Kotyńska, Joanna; Naumowicz, Monika; Figaszewski, Zbigniew A

    2016-06-01

    Equilibria between the membranes of erythrocytes as well as thrombocytes and solution ions in fatal accidental hypothermia were analyzed using a theoretical four-equilibria model. The model was developed to determinate parameters characterizing cell membrane-surrounding ion interactions: the total surface concentrations of both acidic and basic groups C A, C B, and association constants K AH, K BOH. Knowledge of these parameters was necessary to calculate the theoretical values of surface charge density. The model was validated by curve-fitting the experimental data points to simulated data generated by the model. The experimental and theoretical surface charge density values agree at pH 2-8, at higher pH the deviation was observed. PMID:26843064

  6. Calcium phosphate formation on the phosphorylated dental bonding agent in electrolyte solution.

    PubMed

    Hayakawa, T; Yoshinari, M; Sakae, T; Nemoto, K

    2004-01-01

    The aim of the present study was to study the mineral formation on a phosphorylated dental bonding agent using a mineralization inductive solution. Clearfil Photobond, which contained phosphate monomer, was cured by photo-irradiation and heat treated, and was then immersed in Hanks' balanced salt solution (HBSS) with pH = 7.4 for 1, 3, 5, 7, 14, and 28 days at 37 degrees C. The white substances were deposited on the phosphorylated polymer, i.e. cured Photobond disk, after the immersion in HBSS. The white substances become visible after 3 days immersion. After 7 days immersion, surface of the phosphorylated polymer disk was almost covered with white substance layers. The measurement of white substances by means of X-ray diffraction, Fourier-transform infrared and electron probe microanalysis revealed that their main component was carbonate-containing hydroxyapatite. Scanning electron microscopy pictures showed that a large number of globules of hydroxyapatite were fused together, and that each globule was composed of a group of numerous thin-film form flakes uniting and/or clustering together. The results obtained in this study concluded that the presence of phosphonic acid and phosphate group of phosphorylated dental bonding agent enhanced the nucleation and growth of hydroxyapatite crystals on its surface. PMID:15125600

  7. The development of BCB-sealed galvanic cells. Case study: aluminum-platinum cells activated with sodium hypochlorite electrolyte solution

    NASA Astrophysics Data System (ADS)

    Dlutowski, J.; Biver, C. J.; Wang, W.; Knighton, S.; Bumgarner, J.; Langebrake, L.; Moreno, W.; Cardenas-Valencia, A. M.

    2007-08-01

    Energy on demand is an important concept in remote sensor development. The fabrication process for silicon-wafer-based, totally enclosed galvanic cells is presented herein. Benzocyclyobutene (BCB), a photo-patternable material, is used as the adhesive layer between the silicon wafers on which metal electrodes are patterned to form the cells' electrolyte cavity. As a case study, and since aluminum is an anode material with thermodynamic high energy density, this metal is evaporated onto a wafer and used as an anode. A sputtered platinum film collects the charge and provides a catalytic surface in the cell cathode. The metal film patterning process and wafer-to-wafer bonding with BCB is detailed. The difficulties encountered, and design modifications to overcome these, are presented. Cells of the mentioned design were activated with sodium hypochlorite solution electrolyte. Typical potential outputs for the cells, as a function of operational time, are also presented. With a 5 kΩ load, a potential of 1.4 V was maintained for over 240 min, until depletion of the electrolyte occurred. Average cell energy outputs under electrical loads between 100 Ω and 5 kΩ were in the range of 4-10 J with columbic densities ranging from 45 to 83 Ah L-1.

  8. Synthesis of novel acid electrolytes for phosphoric acid fuel cells. Final report, May 1985-October 1988

    SciTech Connect

    Adcock, J.L.

    1988-11-01

    Construction of a 40-millimole-per-hour-scale aerosol direct-fluorination reactor was completed June 26, 1986. F-Methyl F-4-methoxybutanoate and F-4-methoxybutanoyl fluoride were synthesized by aerosol direct fluorination of methyl 4-methoxybutanoate. Basic hydrolysis of the perfluorinated derivatives produce sodium F-4-methoxybutanoate which was pyrolyzed to F-3-methoxy-1-propene. Purification and shipment of 33 grams of F-3-methoxy-1-propene followed. Syntheses by analogous methods allowed production and shipment of 5 grams of F-3-ethoxy-1-propene, 18 grams of F-3-(2-methoxy.ethoxy)-1-propene, and 37 grams of F-3,3-dimethyl-1-butene. Eighteen grams of F-2,2-dimethyl-1-chloropropane was produced directly and shipped. As suggested by other contractors, 5 grams of F-3-methoxy-1-iodopropane, and 5 grams of F-3-(2-methoxy.ethoxy)-1-iodopropane were produced by converting the respective precursor acid sodium salts produced for olefin synthesis to the silver salts and pyrolyzing them with iodine. Each of these compounds was prepared for the first time by the aerosol fluorination process during the course of the contract. These samples were provided to other GRI contractors for synthesis of perfluorinated sulfur(VI) and phosphorous(V) acids.

  9. Development of three-dimensional site-site Smoluchowski-Vlasov equation and application to electrolyte solutions

    SciTech Connect

    Kasahara, Kento; Sato, Hirofumi

    2014-06-28

    Site-site Smoluchowski-Vlasov (SSSV) equation enables us to directly calculate van Hove time correlation function, which describes diffusion process in molecular liquids. Recently, the theory had been extended to treat solute-solvent system by Iida and Sato [J. Chem. Phys. 137, 034506 (2012)]. Because the original framework of SSSV equation is based on conventional pair correlation function, time evolution of system is expressed in terms of one-dimensional solvation structure. Here, we propose a new SSSV equation to calculate time evolution of solvation structure in three-dimensional space. The proposed theory was applied to analyze diffusion processes in 1M NaCl aqueous solution and in lithium ion battery electrolyte solution. The results demonstrate that these processes are properly described with the theory, and the computed van Hove functions are in good agreement with those in previous works.

  10. Development of three-dimensional site-site Smoluchowski-Vlasov equation and application to electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Kasahara, Kento; Sato, Hirofumi

    2014-06-01

    Site-site Smoluchowski-Vlasov (SSSV) equation enables us to directly calculate van Hove time correlation function, which describes diffusion process in molecular liquids. Recently, the theory had been extended to treat solute-solvent system by Iida and Sato [J. Chem. Phys. 137, 034506 (2012)]. Because the original framework of SSSV equation is based on conventional pair correlation function, time evolution of system is expressed in terms of one-dimensional solvation structure. Here, we propose a new SSSV equation to calculate time evolution of solvation structure in three-dimensional space. The proposed theory was applied to analyze diffusion processes in 1M NaCl aqueous solution and in lithium ion battery electrolyte solution. The results demonstrate that these processes are properly described with the theory, and the computed van Hove functions are in good agreement with those in previous works.

  11. Frequency and Temperature Characteristics of an Ultrasonic Method for Measuring the Specific Gravity of Lead-Acid Battery Electrolyte

    NASA Astrophysics Data System (ADS)

    Liu, Jiaxin; Li, Guofeng

    2012-02-01

    In this paper, we present an ultrasonic method for measuring the specific gravity of lead-acid battery electrolyte and study its frequency and temperature characteristics. This method uses an improved frequency scanning ultrasonic pulse echo reflectometer with a two-transducer configuration. The velocity and attenuation coefficient (1 to 30 MHz) of electrolytes with different specific gravities (1.05 to 1.30) are obtained at 25 °C. It has been shown that the ultrasonic velocity changes little with frequency, and there is low attenuation at approximately 5 MHz. The velocities of several electrolytes with different specific gravities are measured in the temperature range from 10 to 50 °C. The thermal transient of the measurement cell is analyzed, showing 0.1% accuracy in specific gravity measurement for a steady temperature and 0.5% accuracy under thermal gradient conditions after temperature compensation. This method is suitable for the on-line, rapid, and accurate measurement of the specific gravity of a lead-acid battery electrolyte.

  12. A unifying mode-coupling theory for transport properties of electrolyte solutions. I. General scheme and limiting laws

    NASA Astrophysics Data System (ADS)

    Contreras Aburto, Claudio; Nägele, Gerhard

    2013-10-01

    We develop a general method for calculating conduction-diffusion transport properties of strong electrolyte mixtures, including specific conductivities, steady-state electrophoretic mobilities, and self-diffusion coefficients. The ions are described as charged Brownian spheres, and the solvent-mediated hydrodynamic interactions (HIs) are also accounted for in the non-instantaneous ion atmosphere relaxation effect. A linear response expression relating long-time partial mobilities to associated dynamic structure factors is employed in our derivation of a general mode coupling theory (MCT) method for the conduction-diffusion properties. A simplified solution scheme for the MCT method is discussed. Analytic results are obtained for transport coefficients of pointlike ions which, for very low ion concentrations, reduce to the Deby-Falkenhagen-Onsager-Fuoss limiting law expressions. As an application, an unusual non-monotonic concentration dependence of the polyion electrophoretic mobility in a mixture of two binary electrolytes is discussed. In addition, leading-order extensions of the limiting law results are derived with HIs included. The present method complements a related MCT method by the authors for the electrolyte viscosity and shear relaxation function [C. Contreras-Aburto and G. Nägele, J. Phys.: Condens. Matter 24, 464108 (2012)], so that a unifying scheme for conduction-diffusion and viscoelastic properties is obtained. We present here the general framework of the method, illustrating its versatility for conditions where fully analytic results are obtainable. Numerical results for conduction-diffusion properties and the viscosity of concentrated electrolytes are presented in Paper II [C. Contreras Aburto and G. Nägele, J. Chem. Phys. 139, 134110 (2013)].

  13. A unifying mode-coupling theory for transport properties of electrolyte solutions. I. General scheme and limiting laws.

    PubMed

    Contreras Aburto, Claudio; Nägele, Gerhard

    2013-10-01

    We develop a general method for calculating conduction-diffusion transport properties of strong electrolyte mixtures, including specific conductivities, steady-state electrophoretic mobilities, and self-diffusion coefficients. The ions are described as charged Brownian spheres, and the solvent-mediated hydrodynamic interactions (HIs) are also accounted for in the non-instantaneous ion atmosphere relaxation effect. A linear response expression relating long-time partial mobilities to associated dynamic structure factors is employed in our derivation of a general mode coupling theory (MCT) method for the conduction-diffusion properties. A simplified solution scheme for the MCT method is discussed. Analytic results are obtained for transport coefficients of pointlike ions which, for very low ion concentrations, reduce to the Deby-Falkenhagen-Onsager-Fuoss limiting law expressions. As an application, an unusual non-monotonic concentration dependence of the polyion electrophoretic mobility in a mixture of two binary electrolytes is discussed. In addition, leading-order extensions of the limiting law results are derived with HIs included. The present method complements a related MCT method by the authors for the electrolyte viscosity and shear relaxation function [C. Contreras-Aburto and G. Nägele, J. Phys.: Condens. Matter 24, 464108 (2012)], so that a unifying scheme for conduction-diffusion and viscoelastic properties is obtained. We present here the general framework of the method, illustrating its versatility for conditions where fully analytic results are obtainable. Numerical results for conduction-diffusion properties and the viscosity of concentrated electrolytes are presented in Paper II [C. Contreras Aburto and G. Nägele, J. Chem. Phys. 139, 134110 (2013)]. PMID:24116554

  14. Process for the recovery of strontium from acid solutions

    DOEpatents

    Horwitz, E. Philip; Dietz, Mark L.

    1992-01-01

    The invention is a process for selectively extracting strontium and technetium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant is a macrocyclic polyether in a diluent which is insoluble in water, but which will itself dissolve a small amount of water. The process will extract strontium and technetium values from nitric acid solutions which are up to 6 molar in nitric acid.

  15. Process for the recovery of strontium from acid solutions

    DOEpatents

    Horwitz, E.P.; Dietz, M.L.

    1992-03-31

    The invention is a process for selectively extracting strontium and technetium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant is a macrocyclic polyether in a diluent which is insoluble in water, but which will itself dissolve a small amount of water. The process will extract strontium and technetium values from nitric acid solutions which are up to 6 molar in nitric acid. 5 figs.

  16. Process for the recovery of strontium from acid solutions

    SciTech Connect

    Horwitz, E.P.; Dietz, M.L.

    1990-12-31

    The invention is a process for selectively extracting strontium and technetium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant is a macrocyclic polyether in a diluent which is insoluble in water, but which will itself dissolve a small amount of water. The process will extract strontium and technetium values from nitric acid solutions which are up to 6 molar in nitric acid.

  17. Water, electrolytes, and acid-base alterations in human immunodeficiency virus infected patients

    PubMed Central

    Musso, Carlos G; Belloso, Waldo H; Glassock, Richard J

    2016-01-01

    The clinical spectrum of human immunodeficiency virus (HIV) infection associated disease has changed significantly over the past decade, mainly due to the wide availability and improvement of combination antiretroviral therapy regiments. Serious complications associated with profound immunodeficiency are nowadays fortunately rare in patients with adequate access to care and treatment. However, HIV infected patients, and particularly those with acquired immune deficiency syndrome, are predisposed to a host of different water, electrolyte, and acid-base disorders (sometimes with opposite characteristics), since they have a modified renal physiology (reduced free water clearance, and relatively increased fractional excretion of calcium and magnesium) and they are also exposed to infectious, inflammatory, endocrinological, oncological variables which promote clinical conditions (such as fever, tachypnea, vomiting, diarrhea, polyuria, and delirium), and may require a variety of medical interventions (antiviral medication, antibiotics, antineoplastic agents), whose combination predispose them to undermine their homeostatic capability. As many of these disturbances may remain clinically silent until reaching an advanced condition, high awareness is advisable, particularly in patients with late diagnosis, concomitant inflammatory conditions and opportunistic diseases. These disorders contribute to both morbidity and mortality in HIV infected patients. PMID:26788462

  18. American Society of Nephrology Quiz and Questionnaire 2013: Electrolyte and Acid-Base

    PubMed Central

    2014-01-01

    The Nephrology Quiz and Questionnaire (NQ&Q) remains an extremely popular session for attendees of the annual meeting of the American Society of Nephrology. As in past years, the conference hall was overflowing with interested audience members. Topics covered by expert discussants included electrolyte and acid-base disorders, glomerular disease, ESRD/dialysis, and transplantation. Complex cases representing each of these categories along with single-best-answer questions were prepared by a panel of experts. Prior to the meeting, program directors of United States nephrology training programs answered questions through an Internet-based questionnaire. A new addition to the NQ&Q was participation in the questionnaire by nephrology fellows. To review the process, members of the audience test their knowledge and judgment on a series of case-oriented questions prepared and discussed by experts. Their answers are compared in real time using audience response devices with the answers of nephrology fellows and training program directors. The correct and incorrect answers are then briefly discussed after the audience responses, and the results of the questionnaire are displayed. This article recapitulates the session and reproduces its educational value for the readers of CJASN. Enjoy the clinical cases and expert discussions. PMID:24558051

  19. Water, electrolytes, and acid-base alterations in human immunodeficiency virus infected patients.

    PubMed

    Musso, Carlos G; Belloso, Waldo H; Glassock, Richard J

    2016-01-01

    The clinical spectrum of human immunodeficiency virus (HIV) infection associated disease has changed significantly over the past decade, mainly due to the wide availability and improvement of combination antiretroviral therapy regiments. Serious complications associated with profound immunodeficiency are nowadays fortunately rare in patients with adequate access to care and treatment. However, HIV infected patients, and particularly those with acquired immune deficiency syndrome, are predisposed to a host of different water, electrolyte, and acid-base disorders (sometimes with opposite characteristics), since they have a modified renal physiology (reduced free water clearance, and relatively increased fractional excretion of calcium and magnesium) and they are also exposed to infectious, inflammatory, endocrinological, oncological variables which promote clinical conditions (such as fever, tachypnea, vomiting, diarrhea, polyuria, and delirium), and may require a variety of medical interventions (antiviral medication, antibiotics, antineoplastic agents), whose combination predispose them to undermine their homeostatic capability. As many of these disturbances may remain clinically silent until reaching an advanced condition, high awareness is advisable, particularly in patients with late diagnosis, concomitant inflammatory conditions and opportunistic diseases. These disorders contribute to both morbidity and mortality in HIV infected patients. PMID:26788462

  20. American Society of Nephrology Quiz and Questionnaire 2015: Electrolytes and Acid-Base Disorders.

    PubMed

    Rosner, Mitchell H; Perazella, Mark A; Choi, Michael J

    2016-04-01

    The Nephrology Quiz and Questionnaire remains an extremely popular session for attendees of the annual Kidney Week meeting of the American Society of Nephrology. During the 2015 meeting the conference hall was once again overflowing with eager quiz participants. Topics covered by the experts included electrolyte and acid-base disorders, glomerular disease, end-stage renal disease and dialysis, and kidney transplantation. Complex cases representing each of these categories together with single-best-answer questions were prepared and submitted by the panel of experts. Before the meeting, training program directors of nephrology fellowship programs and nephrology fellows in the United States answered the questions through an internet-based questionnaire. During the live session members of the audience tested their knowledge and judgment on the same series of case-oriented questions in a quiz. The audience compared their answers in real time using a cell-phone app containing the answers of the nephrology fellows and training program directors. The results of the online questionnaire were displayed, and then the quiz answers were discussed. As always, the audience, lecturers, and moderators enjoyed this highly educational session. This article recapitulates the session and reproduces selected content of educational value for theClinical Journal of the American Society of Nephrologyreaders. Enjoy the clinical cases and expert discussions. PMID:26825098

  1. American Society of Nephrology Quiz and Questionnaire 2013: electrolyte and acid-base.

    PubMed

    Palmer, Biff F; Perazella, Mark A; Choi, Michael J

    2014-06-01

    The Nephrology Quiz and Questionnaire (NQ&Q) remains an extremely popular session for attendees of the annual meeting of the American Society of Nephrology. As in past years, the conference hall was overflowing with interested audience members. Topics covered by expert discussants included electrolyte and acid-base disorders, glomerular disease, ESRD/dialysis, and transplantation. Complex cases representing each of these categories along with single-best-answer questions were prepared by a panel of experts. Prior to the meeting, program directors of United States nephrology training programs answered questions through an Internet-based questionnaire. A new addition to the NQ&Q was participation in the questionnaire by nephrology fellows. To review the process, members of the audience test their knowledge and judgment on a series of case-oriented questions prepared and discussed by experts. Their answers are compared in real time using audience response devices with the answers of nephrology fellows and training program directors. The correct and incorrect answers are then briefly discussed after the audience responses, and the results of the questionnaire are displayed. This article recapitulates the session and reproduces its educational value for the readers of CJASN. Enjoy the clinical cases and expert discussions. PMID:24558051

  2. The key to success: Gelled-electrolyte and optimized separators for stationary lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Toniazzo, Valérie

    The lead acid technology is nowadays considered one of the best suited for stationary applications. Both gel and AGM batteries are complementary technologies and can provide reliability and efficiency due to the constant optimization of the battery design and components. However, gelled-electrolyte batteries remain the preferred technology due to a better manufacturing background and show better performance mainly at low and moderate discharge rates. Especially, using the gel technology allows to get rid of the numerous problems encountered in most AGM batteries: drainage, stratification, short circuits due to dendrites, and mostly premature capacity loss due to the release of internal cell compression. These limitations are the result of the evident lack of an optimal separation system. In gel batteries, on the contrary, highly efficient polymeric separators are nowadays available. Especially, microporous separators based on PVC and silica have shown the best efficiency for nearly 30 years all over the world, and especially in Europe, where the gel technology was born. The improved performance of these separators is explained by the unique extrusion process, which leads to excellent wettability, and optimized physical properties. Because they are the key for the battery success, continuous research and development on separators have led to improved properties, which render the separator even better adapted to the more recent gel technology: the pore size distribution has been optimized to allow good oxygen transfer while avoiding dendrite growth, the pore volume has been increased, the electrical resistance and acid displacement reduced to such an extent that the electrical output of batteries has been raised both in terms of higher capacity and longer cycle life.

  3. Crystalline Li(sub 3)PO(sub 4)/SiO(sub 4) solid solutions as an electrolyte for film batteries using sputtered cathode layers

    NASA Technical Reports Server (NTRS)

    Whitacre, J. F.; West, W. C.

    2003-01-01

    Crystalline solid solutions of 1:1 Li3PO4/SiO4 were synthesized and tested electrochemically using thin film, physical vapor deposited electrodes. After cathode deposition, the electrolyte/cathode structures were annealed at 700 degrees Celsius for 2 hours, a process that resulted in cathode crystallization without encouraging deleterious interfacial reactions. Results indicate that the electrolyte functioned well in this configuration.

  4. Low electrolytic conductivity standards

    SciTech Connect

    Wu, Y.C.; Berezansky, P.A.

    1995-09-01

    The monitoring and control of the quality of feedwater and boiler water are necessary for power plants. The generation of steam at high temperature and pressure requires that contaminants be strictly limited to very low levels to prevent corrosion and scaling. Standards of low electrolytic conductivity were developed to satisfy the demands of the US Navy and American industry for the measurement of high quality water. The criteria for the selection of appropriate solvent and solutes, based on the principles of equivalent conductivity and Onsager`s limiting law, are described. Dilute solutions of potassium chloride and benzoic acid in 30% n-propanol-water have been chosen as standards. The electrolytic conductivity of both sets of these solutions as a function of molality was determined. Solutions of potassium chloride and of benzoic acid are recommended for use as 5, 10, 15, 20, and 25 {micro}S/cm conductivity standards. Solutions prepared from potassium chloride in 30% n-propanol-water have been certified as Standard Reference Materials (SRMs). SRM 3198 and SRM 3199 are certified nominally at 5 and 15 {micro}S/cm, respectively, at 25.000 C.

  5. REDUCTION OF ACIDITY OF NITRIC ACID SOLUTIONS BY USE OF FORMALDEHYDE

    DOEpatents

    Healy, T.V.

    1958-05-20

    A continuous method is described of concentrating by evaporation and reducing the nitrate ion content of an aqueous solution of metallic salts containing nitric acid not in excess of 8N. It consists of heating the solution and then passing formaldehyde into the heated solution to bring about decomposition of the nitric acid. The evolved gases containing NO are contacted countercurrently with an aqueous metal salt solution containing nitric acid in excess of 8N so as to bring about decomposition of the nitric acid and lower the normality to at least 8N, whereupon it is passed into the body of heated solution.

  6. Influence of the active mass particle suspension in electrolyte upon corrosion of negative electrode of a lead-acid battery

    NASA Astrophysics Data System (ADS)

    Kamenev, Yu.; Shtompel, G.; Ostapenko, E.; Leonov, V.

    2014-07-01

    The influence of the suspension of positive active mass particles in the electrolyte on the performance of the negative electrode in a lead-acid battery is studied. A significant increase in the rate of corrosion of the lead electrode is shown when slime particles get in contact with its surface, which may result in the rise of macro-defects on the lugs of the negative electrodes.

  7. Comparison of Polyethylene Glycol-Electrolyte Solution vs Polyethylene Glycol-3350 for the Treatment of Fecal Impaction in Pediatric Patients

    PubMed Central

    Boles, Erin E.; Gaines, Cameryn L.

    2015-01-01

    OBJECTIVES: The objective of this study was to evaluate the safety and efficacy of polyethylene glycol-electrolyte solution vs polyethylene glycol-3350 for the treatment of fecal impaction in pediatric patients. METHODS: A retrospective, observational, institutional review board–approved study was conducted over a 1-year time period. Patients were included in the study if they were admitted to the hospital with a diagnosis of fecal impaction or constipation and were treated with either polyethylene glycol-electrolyte solution (PEG-ES) or polyethylene glycol-3350 (PEG-3350). Patients were excluded if they were discharged prior to resolution of treatment and/or did not receive PEG-ES or PEG-3350. RESULTS: Fifty-one patients (ranging in age from 1 month to 15 years) were evaluated: 23 patients received PEG-ES and 28 patients received PEG-3350. Sex, race, age, and weight were not statistically different between the 2 groups. Resolution of fecal impaction was not significantly different between PEG-ES vs PEG-3350 (87% and 86%, respectively; p = 0.87). There was only 1 reported side effect with PEG-3350, vs 11 reported side effects with PEG-ES (p < 0.01). CONCLUSIONS: Theses results suggest that PEG-3350 is as effective as PEG-ES for the treatment of fecal impaction in pediatric patients and is associated with fewer side effects. PMID:26170773

  8. [Computer modeling the hydrostatic pressure characteristics of the membrane potential for polymeric membrane, separated non-homogeneous electrolyte solutions].

    PubMed

    Slezak, Izabella H; Jasik-Slezak, Jolanta; Rogal, Mirosława; Slezak, Andrzej

    2006-01-01

    On the basis of model equation depending the membrane potential deltapsis, on mechanical pressure difference (deltaP), concentration polarization coefficient (zetas), concentration Rayleigh number (RC) and ratio concentration of solutions separated by membrane (Ch/Cl), the characteristics deltapsis = f(deltaP)zetas,RC,Ch/Cl for steady values of zetas, RC and Ch/Cl in single-membrane system were calculated. In this system neutral and isotropic polymeric membrane oriented in horizontal plane, the non-homogeneous binary electrolytic solutions of various concentrations were separated. Nonhomogeneity of solutions is results from creations of the concentration boundary layers on both sides of the membrane. Calculations were made for the case where on a one side of the membrane aqueous solution of NaCl at steady concentration 10(-3) mol x l(-1) (Cl) was placed and on the other aqueous solutions of NaCl at concentrations from 10(-3) mol x l(-1) to 2 x 10(-2) mol x l(-1) (Ch). Their densities were greater than NaCl solution's at 10(-3) mol x l(-1). It was shown that membrane potential depends on hydrodynamic state of a complex concentration boundary layer-membrane-concentration boundary layer, what is controlled by deltaP, Ch/Cl, RC and zetas. PMID:17022155

  9. Ionic conductivity of dual-phase polymer electrolytes comprised of NBR/SBR latex films swollen with lithium salt solutions

    SciTech Connect

    Matsumoto, Morihiko; Ichino, Toshihiro; Rutt, J.S.; Nishi, Shiro . NTT Interdisciplinary Research Lab.)

    1994-08-01

    Dual-phase polymer electrolytes (DPE) with high ionic conductivity and good mechanical strength were prepared by swelling poly(acrylonitrile-co-butadiene) rubber (NBR) and poly(styrene-co-butadiene) rubber (SBR) mixed latex films with lithium salt solutions (e.g., 1M LiClO[sub 4]/[gamma]-butyrolactone). The latex films retain particle morphology in the solid state. The NBR phase (formed from fused NBR latex particles) is polar and is impregnated selectively with polar lithium salt solutions, yielding ion-conductive channels, whereas the SBR phase (formed from fused SBR latex particles) is nonpolar and is not impregnated, providing a mechanically supportive matrix. The ionic conductivity of the DPE increased dramatically with increasing content of lithium salt solution, and higher amounts of solution were imbibed with increasing content of NBR relative to SBR. Several factors which affect the ionic conductivity of this system were examined, and the highest ionic conductivity (>10[sup [minus]3] S/cm) was obtained when either an NBR/SBR 70/30 (w/w) or a 50/50 (w/w) latex film was saturated with 1M LiClO[sub 4]/[gamma]-BL solution or 1M LiClO[sub 4]/[gamma]-BL/DME solution. Ion-conductive behavior changed critically with increasing lithium salt solution uptake. At low levels of lithium salt solution uptake, evidence suggested that ionic conductivity of the absorbed lithium salt solution was strongly influenced by the presence of the NBR in the ion-conductive channel, but at higher levels, the effects of the NBR were reduced and free'' lithium salt solution was present.

  10. Method for liquid chromatographic extraction of strontium from acid solutions

    DOEpatents

    Horwitz, E. Philip; Dietz, Mark L.

    1992-01-01

    A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

  11. pH dependence of electrokinetic behavior of dolomite and magnesite in aqueous electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Gence, Nermin; Ozbay, Nurgul

    2006-09-01

    In this paper, electrokinetic potential and isoelectric point of dolomite (CaMg(CO 3) 2) and magnesite (MgCO 3) were determined. The effect of various ions such as Mg 2+, Ca 2+, Na + and CO 32- on surface properties of dolomite and magnesite were also examined. Isoelectric points of dolomite and magnesite were determined as 6.3 and 6.8, respectively, in the absence of any electrolyte. H + and OH - ions are the potential determining ions of magnesite and dolomite, as predicted by electrokinetic potential studies.

  12. Calculation of acid-base equilibrium constants at the oxide-electrolyte interface from the dependence of oxide surface charge on pH of the electrolyte

    SciTech Connect

    Gorichev, I.G.; Dorofeev, M.V.; Batrakov, V.V.

    1994-09-01

    The dependences of the catalytic activity of oxides and acid-base properties on ph of solution are similar. A procedure is developed for calculating acid-base equilibrium constants from the dependence of the oxide surface charge q on pH. The values q can be determined by potentiometric titration of aqueous suspensions of oxides. The acid-base equilibrium constants for Fe{sub 3}O{sub 4} and CuO were calculated in accordance with the proposed procedure.

  13. A multi-point sensor based on optical fiber for the measurement of electrolyte density in lead-acid batteries.

    PubMed

    Cao-Paz, Ana M; Marcos-Acevedo, Jorge; del Río-Vázquez, Alfredo; Martínez-Peñalver, Carlos; Lago-Ferreiro, Alfonso; Nogueiras-Meléndez, Andrés A; Doval-Gandoy, Jesús

    2010-01-01

    This article describes a multi-point optical fiber-based sensor for the measurement of electrolyte density in lead-acid batteries. It is known that the battery charging process creates stratification, due to the different densities of sulphuric acid and water. In order to study this process, density measurements should be obtained at different depths. The sensor we describe in this paper, unlike traditional sensors, consists of several measurement points, allowing density measurements at different depths inside the battery. The obtained set of measurements helps in determining the charge (SoC) and state of health (SoH) of the battery. PMID:22319262

  14. A Multi-Point Sensor Based on Optical Fiber for the Measurement of Electrolyte Density in Lead-Acid Batteries

    PubMed Central

    Cao-Paz, Ana M.; Marcos-Acevedo, Jorge; del Río-Vázquez, Alfredo; Martínez-Peñalver, Carlos; Lago-Ferreiro, Alfonso; Nogueiras-Meléndez, Andrés A.; Doval-Gandoy, Jesús

    2010-01-01

    This article describes a multi-point optical fiber-based sensor for the measurement of electrolyte density in lead-acid batteries. It is known that the battery charging process creates stratification, due to the different densities of sulphuric acid and water. In order to study this process, density measurements should be obtained at different depths. The sensor we describe in this paper, unlike traditional sensors, consists of several measurement points, allowing density measurements at different depths inside the battery. The obtained set of measurements helps in determining the charge (SoC) and state of health (SoH) of the battery. PMID:22319262

  15. Improved electrolytes for fuel cells

    SciTech Connect

    Gard, G.L.; Roe, D.K.

    1991-06-01

    Present day fuel cells based upon hydrogen and oxygen have limited performance due to the use of phosphoric acid as an electrolyte. Improved performance is desirable in electrolyte conductivity, electrolyte management, oxygen solubility, and the kinetics of the reduction of oxygen. Attention has turned to fluorosulfonic acids as additives or substitute electrolytes to improve fuel cell performance. The purpose of this project is to synthesize and electrochemically evaluate new fluorosulfonic acids as superior alternatives to phosphoric acid in fuel cells. (VC)

  16. [Computer modeling the concentration characteristics of the membrane potential for polymeric membrane, separated non-homogeneous electrolyte solutions].

    PubMed

    Slezak, Izabella H; Jasik-Slezak, Jolanta; Rogal, Mirosława; Slezak, Andrzej

    2006-01-01

    The influence of the concentration boundary layers on membrane potential (deltapsis) in a single-membrane system on basis of the Kedem-Katchalsky equations was described in cases of horizontally mounted neutral polymeric membrane separates non-homogeneous (mechanically unstirred) binary electrolytic solutions at different concentrations. Results of calculations of deltapsis as a function of ratio solution concentrations (Ch/Cl) at constant values of: concentration Rayleigh number (Rc), concentration polarization coefficient (zetas) and hydrostatic pressure (deltaP) were presented. Calculations were made for the case where on a one side of the membrane aqueous solution of NaCl at steady concentration 10(-3) mol x l(-1) (Cl) was placed and on the other aqueous solutions of NaCl at concentrations from 10(-3) mol x l(-1) to 2 x 10(-2) mol x l(-1) (Ch). Their densities were greater than NaCl solution's at 10(-3) mol x l(-1). It was shown that membrane potential depends on hydrodynamic state of a complex concentration boundary layer-membrane-concentration boundary layer, what is controlled by deltaP, Ch/Cl, Rc and zetas. PMID:17022154

  17. Adsorption and corrosion inhibition properties of thiocarbanilide on the electrochemical behavior of high carbon steel in dilute acid solutions

    NASA Astrophysics Data System (ADS)

    Loto, Roland Tolulope; Loto, Cleophas Akintoye; Joseph, Olufunmilayo; Olanrewaju, Gabriel

    The inhibition performance of thiocarbanilide on the electrochemical corrosion behavior of high carbon steel in 1 M H2SO4 and HCl acid solutions was studied through weight loss method and potentiodynamic polarization test. Data obtained showed that the organic compound performed effectively in acid solutions at all concentrations with an average thiocarbanilide inhibition efficiency above 70% in H2SO4 acid and 80% in HCl acid from weight loss and potentiodynamic polarization test respectively. Results from corrosion thermodynamic calculations showed that the adsorption of thiocarbanilide onto the steel was through chemisorption mechanism whereby the redox electrochemical process responsible for corrosion and the electrolytic transport of corrosive anions were simultaneously suppressed. Statistical derivations through ANOVA analysis confirm that the influences of both the inhibitor concentration and exposure time on inhibition efficiency values are negligible. Adsorption of the compound was determined to obey the Langmuir and Frumkin isotherm model.

  18. Removal of heavy metals from a chelated solution with electrolytic foam separation

    SciTech Connect

    Min-Her Leu; Juu-En Chang; Ming-Sheng Ko

    1994-11-01

    An experimental study was conducted on the chelation and electrolytic foam separation of trace amounts of copper, nickel, zinc, and cadmium from a synthetic chelated metal wastewater. Sodium ethylenediaminetetraacetate (EDTA), citrate, sodium diethyldithiocarbamate (NDDTC), and potassium ethyl xanthate (KEtX) were used with sodium dodecylsulfate (NaDS) as a foam-producing agent. Experimental results from an electrolytic foam separation process showed that chelating agents NDDTC and KEtX, due to their higher chelating strength and hydrophobic property, can efficiently separate Cu and Ni from chelated compounds (Cu, Ni/EDTA, and Cu, Ni/citrate). In a Cu-EDTA-NDDTC system with a chelating agent/metal ratio of 4, the residual Cu(II) concentration is 0.7 mg/L. The effects of chelating agent types and different chelating agents concentrations on the removal of metal ions were studied. The effect of NaDS dosage on flotation behavior and the efficiency of metal removal were also investigated.

  19. A comparison of three oral electrolyte solutions in the treatment of diarrheic calves

    PubMed Central

    Naylor, Jonathan M.; Petrie, Lyall; Rodriguez, Maria I.; Skilnick, Patricia

    1990-01-01

    Thirty-six diarrheic calves infected with rota- and coronaviruses were randomly allocated to one of three oral electrolyte treatments: Ion-Aid (Syntex Agribusiness), Life-Guard (Norden Inc), or Revibe (Langford Inc). The calves were also allowed voluntary access to milk which was offered at the rate of 5% of body weight per feeding in two feedings daily. There were significant differences in recovery rate among calves treated with the different electrolytes. Only 33% of Ion-Aid-treated calves recovered; Revibe- and Life-Guard-treated calves had high recovery rates of 92% and 83%, respectively. The much higher recovery rates with Life-Guard and Revibe were attributed to the presence of an alkalizing agent in these preparations. Life-Guard uses bicarbonate to counteract acidosis and there was some evidence that this may have interfered with milk digestion. Revibe uses acetate; this was effectively metabolized within the calves' tissues and produced alkalization without interference with milk digestion. PMID:17423689

  20. Decomposition Studies of Triphenylboron, Diphenylborinic Acid and Phenylboric Acid in Aqueous Alkaline Solutions Containing Copper

    SciTech Connect

    Crawford, C.L.; Peterson, R. A.

    1997-02-11

    This report documents the copper-catalyzed chemical kinetics of triphenylboron, diphenylborinic acid and phenylboric acid (3PB, 2PB and PBA) in aqueous alkaline solution contained in carbon-steel vessels between 40 and 70 degrees C.

  1. Mode coupling theory analysis of electrolyte solutions: Time dependent diffusion, intermediate scattering function, and ion solvation dynamics

    NASA Astrophysics Data System (ADS)

    Roy, Susmita; Yashonath, Subramanian; Bagchi, Biman

    2015-03-01

    A self-consistent mode coupling theory (MCT) with microscopic inputs of equilibrium pair correlation functions is developed to analyze electrolyte dynamics. We apply the theory to calculate concentration dependence of (i) time dependent ion diffusion, (ii) intermediate scattering function of the constituent ions, and (iii) ion solvation dynamics in electrolyte solution. Brownian dynamics with implicit water molecules and molecular dynamics method with explicit water are used to check the theoretical predictions. The time dependence of ionic self-diffusion coefficient and the corresponding intermediate scattering function evaluated from our MCT approach show quantitative agreement with early experimental and present Brownian dynamic simulation results. With increasing concentration, the dispersion of electrolyte friction is found to occur at increasingly higher frequency, due to the faster relaxation of the ion atmosphere. The wave number dependence of intermediate scattering function, F(k, t), exhibits markedly different relaxation dynamics at different length scales. At small wave numbers, we find the emergence of a step-like relaxation, indicating the presence of both fast and slow time scales in the system. Such behavior allows an intriguing analogy with temperature dependent relaxation dynamics of supercooled liquids. We find that solvation dynamics of a tagged ion exhibits a power law decay at long times—the decay can also be fitted to a stretched exponential form. The emergence of the power law in solvation dynamics has been tested by carrying out long Brownian dynamics simulations with varying ionic concentrations. The solvation time correlation and ion-ion intermediate scattering function indeed exhibit highly interesting, non-trivial dynamical behavior at intermediate to longer times that require further experimental and theoretical studies.

  2. General electrokinetic model for concentrated suspensions in aqueous electrolyte solutions: Electrophoretic mobility and electrical conductivity in static electric fields.

    PubMed

    Carrique, Félix; Ruiz-Reina, Emilio; Roa, Rafael; Arroyo, Francisco J; Delgado, Ángel V

    2015-10-01

    In recent years different electrokinetic cell models for concentrated colloidal suspensions in aqueous electrolyte solutions have been developed. They share some of its premises with the standard electrokinetic model for dilute colloidal suspensions, in particular, neglecting both the specific role of the so-called added counterions (i.e., those released by the particles to the solution as they get charged), and the realistic chemistry of the aqueous solution on such electrokinetic phenomena as electrophoresis and electrical conductivity. These assumptions, while having been accepted for dilute conditions (volume fractions of solids well below 1%, say), are now questioned when dealing with concentrated suspensions. In this work, we present a general electrokinetic cell model for such kind of systems, including the mentioned effects, and we also carry out a comparative study with the standard treatment (the standard solution only contains the ions that one purposely adds, without ionic contributions from particle charging or water chemistry). We also consider an intermediate model that neglects the realistic aqueous chemistry of the solution but accounts for the correct contribution of the added counterions. The results show the limits of applicability of the classical assumptions and allow one to better understand the relative role of the added counterions and ions stemming from the electrolyte in a realistic aqueous solution, on electrokinetic properties. For example, at low salt concentrations the realistic effects of the aqueous solution are the dominant ones, while as salt concentration is increased, it is this that progressively takes the control of the electrokinetic response for low to moderate volume fractions. As expected, if the solids concentration is high enough the added counterions will play the dominant role (more important the higher the particle surface charge), no matter the salt concentration if it is not too high. We hope this work can help in

  3. Studies on the effect of acid treated TiO{sub 2} on the electrical and tensile properties of hexanoyl chitosan-polystyrene-LiCF{sub 3}SO{sub 3} composite polymer electrolytes

    SciTech Connect

    Hanif, Nur Shazlinda Muhammad; Shahril, Nur Syuhada Mohd; Azmar, Amisha; Winie, Tan

    2015-08-28

    Composite polymer electrolytes (CPEs) comprised of hexanoyl chitosan:polystyrene (90:10) blend, lithium triflouromethanesulfonate (LiCF{sub 3}SO{sub 3}) salt and titanium oxide (TiO{sub 2}) filler were prepared by solution casting technique. The TiO{sub 2} fillers were treated with 2% sulphuric acid (H{sub 2}SO{sub 4}) aqueous solution. The effect of acid treated TiO{sub 2} on the electrical and tensile properties of the electrolytes were investigated. Acid treated TiO{sub 2} decreased the electrolyte conductivity. Both the dielectric constant and dielectric loss decrease with increasing frequency and increases with increasing temperature. Relaxation times for ionic carriers were extracted from the loss tangent maximum peak at various temperatures. A distribution of relaxation time implied the non-Debye response. At all frequencies, ac conductivity increases with increasing temperature. An enhancement in the Young’s modulus was observed with the addition of TiO{sub 2}. The Young’s modulus increases with increasing TiO{sub 2} content. This is discussed using the percolation concept.

  4. Nylon Dissolution in Nitric Acid Solutions

    SciTech Connect

    KESSINGER, GLENF.

    2004-06-16

    H Area Operations is planning to process Pu-contaminated uranium scrap in support of de-inventory efforts. Nylon bags will be used to hold materials to be dissolved in H-Canyon. Based on this set of twelve nylon dissolutions, it is concluded that (when other variables are held constant): increased acid concentration results in increased dissolution rates; increased acid concentration results in a lower dissolution onset temperature; little, if any, H plus is consumed during the depolymerization process; and 2.0-3.0 M HNO3, with 0.025 M KF and 2 g/L B, is satisfactory for the dissolution of nylon bag materials to be used during H-Canyon processing.

  5. Substrate Selection for Fundamental Studies of Electrocatalysts and Photoelectrodes: Inert Potential Windows in Acidic, Neutral, and Basic Electrolyte

    PubMed Central

    Gorlin, Yelena; Jaramillo, Thomas F.

    2014-01-01

    The selection of an appropriate substrate is an important initial step for many studies of electrochemically active materials. In order to help researchers with the substrate selection process, we employ a consistent experimental methodology to evaluate the electrochemical reactivity and stability of seven potential substrate materials for electrocatalyst and photoelectrode evaluation. Using cyclic voltammetry with a progressively increased scan range, we characterize three transparent conducting oxides (indium tin oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide) and four opaque conductors (gold, stainless steel 304, glassy carbon, and highly oriented pyrolytic graphite) in three different electrolytes (sulfuric acid, sodium acetate, and sodium hydroxide). We determine the inert potential window for each substrate/electrolyte combination and make recommendations about which materials may be most suitable for application under different experimental conditions. Furthermore, the testing methodology provides a framework for other researchers to evaluate and report the baseline activity of other substrates of interest to the broader community. PMID:25357131

  6. Raman spectra of amino acids and their aqueous solutions

    NASA Astrophysics Data System (ADS)

    Zhu, Guangyong; Zhu, Xian; Fan, Qi; Wan, Xueliang

    2011-03-01

    Amino acids are the basic "building blocks" that combine to form proteins and play an important physiological role in all life-forms. Amino acids can be used as models for the examination of the importance of intermolecular bonding in life processes. Raman spectra serve to obtain information regarding molecular conformation, giving valuable insights into the topology of more complex molecules (peptides and proteins). In this paper, amino acids and their aqueous solution have been studied by Raman spectroscopy. Comparisons of certain values for these frequencies in amino acids and their aqueous solutions are given. Spectra of solids when compared to those of the solute in solution are invariably much more complex and almost always sharper. We present a collection of Raman spectra of 18 kinds of amino acids ( L-alanine, L-arginine, L-aspartic acid, cystine, L-glutamic acid, L-glycine, L-histidine, L-isoluecine, L-leucine, L-lysine, L-phenylalanine, L-methionone, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine, L-valine) and their aqueous solutions that can serve as references for the interpretation of Raman spectra of proteins and biological materials.

  7. Polymerization of beta-amino acids in aqueous solution

    NASA Technical Reports Server (NTRS)

    Liu, R.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

    1998-01-01

    We have compared carbonyl diimidazole (CDI) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as activating agents for the oligomerization of negatively-charged alpha- and beta-amino acids in homogeneous aqueous solution. alpha-Amino acids can be oligomerized efficiently using CDI, but not by EDAC. beta-Amino acids can be oligomerized efficiently using EDAC, but not by CDI. Aspartic acid, an alpha- and beta-dicarboxylic acid is oligomerized efficiently by both reagents. These results are explained in terms of the mechanisms of the reactions, and their relevance to prebiotic chemistry is discussed.

  8. Radiolysis as a solution for accelerated ageing studies of electrolytes in Lithium-ion batteries.

    PubMed

    Ortiz, Daniel; Steinmetz, Vincent; Durand, Delphine; Legand, Solène; Dauvois, Vincent; Maître, Philippe; Le Caër, Sophie

    2015-01-01

    Diethyl carbonate and dimethyl carbonate are prototype examples of eco-friendly solvents used in lithium-ion batteries. Nevertheless, their degradation products affect both the battery performance and its safety. Therefore, it is of paramount importance to understand the reaction mechanisms involved in the ageing processes. Among those, redox processes are likely to play a critical role. Here we show that radiolysis is an ideal tool to generate the electrolytes degradation products. The major gases detected after irradiation (H2, CH4, C2H6, CO and CO2) are identified and quantified. Moreover, the chemical compounds formed in the liquid phase are characterized by different mass spectrometry techniques. Reaction mechanisms are then proposed. The detected products are consistent with those of the cycling of Li-based cells. This demonstrates that radiolysis is a versatile and very helpful tool to better understand the phenomena occurring in lithium-ion batteries. PMID:25907411

  9. Radiolysis as a solution for accelerated ageing studies of electrolytes in Lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Ortiz, Daniel; Steinmetz, Vincent; Durand, Delphine; Legand, Solène; Dauvois, Vincent; Maître, Philippe; Le Caër, Sophie

    2015-04-01

    Diethyl carbonate and dimethyl carbonate are prototype examples of eco-friendly solvents used in lithium-ion batteries. Nevertheless, their degradation products affect both the battery performance and its safety. Therefore, it is of paramount importance to understand the reaction mechanisms involved in the ageing processes. Among those, redox processes are likely to play a critical role. Here we show that radiolysis is an ideal tool to generate the electrolytes degradation products. The major gases detected after irradiation (H2, CH4, C2H6, CO and CO2) are identified and quantified. Moreover, the chemical compounds formed in the liquid phase are characterized by different mass spectrometry techniques. Reaction mechanisms are then proposed. The detected products are consistent with those of the cycling of Li-based cells. This demonstrates that radiolysis is a versatile and very helpful tool to better understand the phenomena occurring in lithium-ion batteries.

  10. Radiolysis as a solution for accelerated ageing studies of electrolytes in Lithium-ion batteries

    PubMed Central

    Ortiz, Daniel; Steinmetz, Vincent; Durand, Delphine; Legand, Solène; Dauvois, Vincent; Maître, Philippe; Le Caër, Sophie

    2015-01-01

    Diethyl carbonate and dimethyl carbonate are prototype examples of eco-friendly solvents used in lithium-ion batteries. Nevertheless, their degradation products affect both the battery performance and its safety. Therefore, it is of paramount importance to understand the reaction mechanisms involved in the ageing processes. Among those, redox processes are likely to play a critical role. Here we show that radiolysis is an ideal tool to generate the electrolytes degradation products. The major gases detected after irradiation (H2, CH4, C2H6, CO and CO2) are identified and quantified. Moreover, the chemical compounds formed in the liquid phase are characterized by different mass spectrometry techniques. Reaction mechanisms are then proposed. The detected products are consistent with those of the cycling of Li-based cells. This demonstrates that radiolysis is a versatile and very helpful tool to better understand the phenomena occurring in lithium-ion batteries. PMID:25907411

  11. Vacuum-jacketed hydrofluoric acid solution calorimeter

    USGS Publications Warehouse

    Robie, R.A.

    1965-01-01

    A vacuum-jacketed metal calorimeter for determining heats of solution in aqueous HF was constructed. The reaction vessel was made of copper and was heavily gold plated. The calorimeter has a cooling constant of 0.6 cal-deg -1-min-1, approximately 1/4 that of the air-jacketed calorimeters most commonly used with HF. It reaches equilibrium within 10 min after turning off the heater current. Measurements of the heat of solution of reagent grade KCl(-100 mesh dried 2 h at 200??C) at a mole ratio of 1 KCl to 200 H2O gave ??H = 4198??11 cal at 25??C. ?? 1965 The American Institute of Physics.

  12. Impact of particle size on interaction forces between ettringite and dispersing comb-polymers in various electrolyte solutions.

    PubMed

    Ferrari, Lucia; Kaufmann, Josef; Winnefeld, Frank; Plank, Johann

    2014-04-01

    The inter-particle forces play a fundamental role for the flow properties of a particle suspension in response to shear stresses. In concrete applications, cement admixtures based on comb-polymers like polycarboxylate-ether-based superplasticizer (PCE) are used to control the rheological behavior of the fresh mixtures, as it is negatively impacted by certain early hydration products, like the mineral ettringite. In this work, dispersion forces due to PCE were measured directly at the surface of ettringite crystals in different electrolyte solutions by the means of atomic force microscopy (AFM) applying spherical and sharp silicon dioxide tips. Results show an effective repulsion between ettringite surface and AFM tips for solutions above the IEP of ettringite (pH∼12) and significant attraction in solution at lower pH. The addition of polyelectrolytes in solution provides dispersion forces exclusively between the sharp tips (radius ≈ 10 nm) and the ettringite surface, whereas the polymer layer at the ettringite surface results to be unable to disperse large colloidal probes (radius ≈ 10 μm). A simple modeling of the inter-particle forces explains that, for large particles, the steric hindrance of the studied PCE molecules is not high enough to compensate for the Van der Waals and the attractive electrostatic contributions. Therefore, in cement suspensions the impact of ettringite on rheology is probably not only related to the particle charge, but also related to the involved particle sizes. PMID:24491324

  13. Method for incorporating radioactive phosphoric acid solutions in concrete

    DOEpatents

    Wolf, Gary A [Kennewick, WA; Smith, Jeffrey W [Lancaster, OH; Ihle, Nathan C [Walla Walla, WA

    1984-01-01

    A method for incorporating radioactive phosphoric acid solutions in concrete is described wherein the phosphoric acid is reacted with Ca(OH).sub.2 to form a precipitate of hydroxyapatite and the hydroxyapatite is mixed with portland cement to form concrete.

  14. Method for incorporating radioactive phosphoric acid solutions in concrete

    DOEpatents

    Wolf, G.A.; Smith, J.W.; Ihle, N.C.

    1982-07-08

    A method for incorporating radioactive phosphoric acid solutions in concrete is described wherein the phosphoric acid is reacted with Ca(OH)/sub 2/ to form a precipitate of hydroxyapatite and the hydroxyapatite is mixed with Portland cement to form concrete.

  15. Improved method for extracting lanthanides and actinides from acid solutions

    DOEpatents

    Horwitz, E.P.; Kalina, D.G.; Kaplan, L.; Mason, G.W.

    1983-07-26

    A process for the recovery of actinide and lanthanide values from aqueous acidic solutions uses a new series of neutral bi-functional extractants, the alkyl(phenyl)-N,N-dialkylcarbamoylmethylphosphine oxides. The process is suitable for the separation of actinide and lanthanide values from fission product values found together in high-level nuclear reprocessing waste solutions.

  16. RECOVERY OF ACTINIDES FROM AQUEOUS NITRIC ACID SOLUTIONS

    DOEpatents

    Ader, M.

    1963-11-19

    A process of recovering actinides is presented. Tetravalent actinides are extracted from rare earths in an aqueous nitric acid solution with a ketone and back-extracted from the ketone into an aqueous medium. The aqueous actinide solution thus obtained, prior to concentration by boiling, is sparged with steam to reduce its ketone to a maximum content of 3 grams per liter. (AEC)

  17. Phosphorylation of Glyceric Acid in Aqueous Solution Using Trimetaphosphate

    NASA Technical Reports Server (NTRS)

    Kolb, Vera; Orgel, Leslie E.

    1996-01-01

    The phosphorylation of glyceric acid is an interesting prebiotic reaction because it converts a simple, potentially prebiotic organic molecule into phosphate derivatives that are central to carbohydrate metabolism. We find that 0.05 M glyceric acid in the presence of 0.5 M trimetaphosphate in alkaline solution gives a mixture of 2- and 3-phosphoglyceric acids in combined yields of up to 40%.

  18. A conductivity study of unsymmetrical 2:1 type "complex ion" electrolyte: cadmium chloride in dilute aqueous solutions.

    PubMed

    Apelblat, Alexander; Esteso, Miguel A; Bešter-Rogač, Marija

    2013-05-01

    Systematic and precise measurements of electrical conductivities of aqueous solutions of cadmium chloride were performed in the 2 × 10(-5)-1 × 10(-2) mol·dm(-3) concentration range, from 278.15 to 313.15 K. Determined conductances were interpreted in terms of molecular model which includes a mixture of two 1:1 and 2:1 electrolytes. The molar limiting conductances of λ(0)(CdCl(+), T) and λ(0)(1/2Cd(2+), T), the equilibrium constants of CdCl(+) formation K(T) and the corresponding standard thermodynamic functions were evaluated using the Quint-Viallard conductivity equations, the Debye-Hückel equations for activity coefficients and the mass-action equation. An excellent agreement between calculated and experimental conductivities was reached. PMID:23534843

  19. A novel flow battery-A lead-acid battery based on an electrolyte with soluble lead(II). Part VI. Studies of the lead dioxide positive electrode

    NASA Astrophysics Data System (ADS)

    Pletcher, Derek; Zhou, Hantao; Kear, Gareth; Low, C. T. John; Walsh, Frank C.; Wills, Richard G. A.

    The structure of thick lead dioxide deposits (approximately 1 mm) formed in conditions likely to be met at the positive electrode during the charge/discharge cycling of a soluble lead-acid flow battery is examined. Compact and well adherent layers are possible with current densities >100 mA cm -2 in electrolytes containing 0.1-1.5 M lead(II) and methanesulfonic acid concentrations in the range 0-2.4 M; the solutions also contained 5 mM hexadecyltrimethylammonium cation, C 16H 33(CH 3) 3N +. From the viewpoint of the layer properties, the limitation is stress within the deposit leading to cracking and lifting away from the substrate; the stress appears highest at high acid concentration and high current density. There are, however, other factors limiting the maximum current density for lead dioxide deposition, namely oxygen evolution and the overpotential associated with the deposition of lead dioxide. A strategy for operating the soluble lead-acid flow battery is proposed.

  20. Multi-electrolyte-step anodic aluminum oxide method for the fabrication of self-organized nanochannel arrays

    PubMed Central

    2012-01-01

    Nanochannel arrays were fabricated by the self-organized multi-electrolyte-step anodic aluminum oxide [AAO] method in this study. The anodization conditions used in the multi-electrolyte-step AAO method included a phosphoric acid solution as the electrolyte and an applied high voltage. There was a change in the phosphoric acid by the oxalic acid solution as the electrolyte and the applied low voltage. This method was used to produce self-organized nanochannel arrays with good regularity and circularity, meaning less power loss and processing time than with the multi-step AAO method. PMID:22333268

  1. Capillary electrophoresis of some free fatty acids using partially aqueous electrolyte systems and indirect UV detection. Application to the analysis of oleic and linoleic acids in peanut breeding lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study has shown for the first time the suitability of CE with a partially aqueous electrolyte system for the analysis of free fatty acids (FFA's) in small portions of single peanut seeds. The partially aqueous electrolyte system consisted of 40 mM Tris, 2.5 mM adenosine-5'-monophosphate (AMP) ...

  2. Reduction of Plutonium in Acidic Solutions by Mesoporous Carbons

    SciTech Connect

    Parsons-Moss, Tashi; Jones, Stephen; Wang, Jinxiu; Wu, Zhangxiong; Uribe, Eva; Zhao, Dongyuan; Nitsche, Heino

    2015-12-19

    Batch contact experiments with several porous carbon materials showed that carbon solids spontaneously reduce the oxidation state of plutonium in 1-1.5 M acid solutions, without significant adsorption. The final oxidation state and rate of Pu reduction varies with the solution matrix, and also depends on the surface chemistry and surface area of the carbon. It was demonstrated that acidic Pu(VI) solutions can be reduced to Pu(III) by passing through a column of porous carbon particles, offering an easy alternative to electrolysis with a potentiostat.

  3. REMOVAL OF CHLORIDE FROM ACIDIC SOLUTIONS USING NO2

    SciTech Connect

    Visser, A; Robert Pierce, R; James Laurinat, J

    2006-08-22

    Chloride (Cl{sup -}) salt processing in strong acids is used to recycle plutonium (Pu) from pyrochemical residues. The Savannah River National Laboratory (SRNL) is studying the potential application of nitrogen dioxide (NO{sub 2}) gas to effectively convert dissolved pyrochemical salt solutions to chloride-free solutions and improve recovery operations. An NO{sub 2} sparge has been shown to effectively remove Cl{sup -} from solutions containing 6-8 M acid (H{sup +}) and up to 5 M Cl{sup -}. Chloride removal occurs as a result of the competition of at least two reactions, one which is acid-dependent. Below 4 M H+, NO2 reacts with Cl- to produce nitrosyl chloride (ClNO). Between 6 M and 8 M H{sup +}, the reaction of hydrochloric acid (HCl) with nitric acid (HNO{sub 3}), facilitated by the presence of NO{sub 2}, strongly affects the rate of Cl{sup -} removal. The effect of heating the acidic Cl{sup -} salt solution without pre-heating the NO{sub 2} gas has minimal effect on Cl{sup -} removal rates when the contact times between NO{sub 2} and the salt solution are on the order of seconds.

  4. Evaluation of localized corrosion of zirconium in acidic chloride solutions

    SciTech Connect

    Fahey, J.; Holmes, D.; Yau, T.L.

    1997-01-01

    Zirconium is prone to localized corrosion in acidic chloride (Cl{sup {minus}}) solutions contaminated by oxidizing ions, such as ferric or cupric ions. This tendency can be reduced by ensuring that the zirconium surface is clean and smooth. The effect of surface condition on localized corrosion of zirconium in acidic chloride solutions was predicted using potentiodynamic polarization scans. Predictions were confirmed by mass-loss tests on various combinations of surface finish and acid concentrations. A real-time indication of localized corrosion was derived by monitoring electrochemical noise produced between two similar electrodes immersed in an acidic chloride solution. Electrochemical noise monitoring correlated well with predictions from the potentiodynamic polarization and mass-loss experiments. Electrochemical noise results showed a more anodic potential caused by ferric ion (Fe{sup 3+}) contamination might be necessary for localized corrosion but that it was not a sufficient condition. A clean zirconium surface reduced localized corrosion of zirconium.

  5. Does addition of an electrolyte influence the rotational diffusion of nondipolar solutes in a protic ionic liquid?

    PubMed

    Prabhu, Sugosh R; Dutt, G B

    2015-05-21

    Rotational diffusion of two structurally similar nondipolar solutes, 2,5-dimethyl-1,4-dioxo-3,6-diphenylpyrrolo[3,4-c]pyrrole (DMDPP) and 1,4-dioxo-3,6-diphenylpyrrolo[3,4-c]pyrrole (DPP), has been examined in ethylammonium nitrate-lithium nitrate (EAN-LiNO3) mixtures to understand the influence of added electrolyte on the local environment experienced by the solute molecules. The measured reorientation times of both DMDPP and DPP in EAN-LiNO3 mixtures fall within the broad limits set by the hydrodynamic slip and stick boundary conditions. The hydrogen bond accepting DMDPP and the hydrogen bond donating DPP experience specific interactions with the cation and anion of the ionic liquid, respectively. Addition of LiNO3 (0.1 and 0.2 mole fraction) to EAN induces only viscosity related effects on the rotational diffusion of the two nondipolar solutes. These observations suggest that the local environment experienced by DMDPP and DPP in EAN is not altered upon the addition of LiNO3. Our results are consistent with the structural details available in the literature for EAN-LiNO3 mixtures. PMID:25914928

  6. Molecular dynamics simulations of carbon dioxide hydrate growth in electrolyte solutions of NaCl and MgCl2

    NASA Astrophysics Data System (ADS)

    Yi, Lizhi; Liang, Deqing; Zhou, Xuebing; Li, Dongliang; Wang, Jianwei

    2014-12-01

    Molecular dynamics simulations are performed to study the growth of carbon dioxide (CO2) hydrate in electrolyte solutions of NaCl and MgCl2. The kinetic behaviour of the hydrate growth is examined in terms of cage content, density profile, and mobility of ions and water molecules, and how these properties are influenced by added NaCl and MgCl2. Our simulation results show that both NaCl and MgCl2 inhibit the CO2 hydrate growth. With a same mole concentration or ion density, MgCl2 exhibits stronger inhibition on the growth of CO2 hydrate than NaCl does. The growth rate of the CO2 hydrate in NaCl and MgCl2 solutions decreases slightly with increasing pressure. During the simulations, the Na+, Mg2+, and Cl- ions are mostly excluded by the growing interface front. We find that these ions decrease the mobility of their surrounding water molecules, and thus reduce the opportunity for these water molecules to form cage-like clusters toward hydrate formation. We also note that during the growth processes, several 51263 cages appear at the hydrate/solution interface, although they are finally transformed to tetrakaidecahedral (51262) cages. Structural defects consisting of one water molecule trapped in a cage with its hydrogen atoms being attracted by two Cl- ions have also been observed.

  7. Quantitative Real-Time Measurements of DNA Hybridization with Alkylated Non-Oxidized Silicon Nanowires in Electrolyte Solution

    PubMed Central

    Bunimovich, Yuri L.; Shin, Young Shik; Yeo, Woon-Seok; Amori, Michael; Kwong, Gabriel

    2013-01-01

    The quantitative, real time detection of single stranded oligonucleotides with silicon nanowires (SiNWs) in physiologically relevant electrolyte solution is demonstrated. Debye screening of the hybridization event is minimized by utilizing electrostatically adsorbed primary DNA on an amine-terminated NW surface. Two surface functionalization chemistries are compared: an amine terminated siloxane monolayer on the native SiO2 surface of the SiNW, and an amine terminated alkyl monolayer grown directly on a hydrogen-terminated SiNW surface. The SiNWs without the native oxide exhibit improved solution-gated field-effect transistor characteristics and a significantly enhanced sensitivity to single stranded DNA detection, with an accompanying two orders of magnitude improvement in the dynamic range of sensing. A model for the detection of analyte by SiNW sensors is developed and utilized to extract DNA binding kinetic parameters. Those values are directly compared with values obtained by the standard method of surface plasmon resonance (SPR), and demonstrated to be similar. The nanowires, however, are characterized by higher detection sensitivity. The implication is that Si NWs can be utilized to quantitate the solution phase concentration of biomolecules at low concentrations. This work also demonstrates the importance of surface chemistry for optimizing biomolecular sensing with silicon nanowires. PMID:17165787

  8. Investigation and application of polysiloxane-based gel electrolyte in valve-regulated lead-acid battery

    NASA Astrophysics Data System (ADS)

    Tang, Zheng; Wang, Jianming; Mao, Xian-xian; Shao, Haibo; Chen, Quanqi; Xu, Zhihua; Zhang, Jianqing

    Polysiloxane-based gel electrolyte (PBGE) is prepared and investigated as a new gel electrolyte for valve-regulated lead-acid (VRLA) batteries. PBGE particles, characterized by means of Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry (CV) and scanning electron microscopy (SEM), reveal good stability and their particle sizes are 30-50 nm. The initial cyclic properties of the absorptive glass mat (AGM)-PBGE and AGM-colloid silica gel electrolyte (CSGE) hybrid batteries are investigated by electrochemical techniques, scanning electron microscopy and X-ray diffraction (XRD). The addition of PBGE improves the utilization efficiency of positive active material (PAM) in AGM-PBGE hybrid batteries and thus enhances the batteries capacity compared with the AGM-CSGE reference batteries. Cyclic overdischarge tests show that the AGM-PBGE hybrid batteries have superior recharge and discharge during partial-state-of-charge (PSoC). It is also found that the greatly enhanced electrochemical performance of the AGM-PBGE batteries may be due to higher charge efficiency, good conductivity with lower internal resistance and the open three-dimensional network structure of the polyelectrolyte. The analysis results of SEM and XRD indicate that softening and shedding of positive active material are the main causes of failure for the two hybrid batteries.

  9. ELECTROLYTIC PRODUCTION OF URANIUM TETRAFLUORIDE

    DOEpatents

    Lofthouse, E.

    1954-08-31

    This patent relates to electrolytic methods for the production of uranium tetrafluoride. According to the present invention a process for the production of uranium tetrafluoride comprises submitting to electrolysis an aqueous solution of uranyl fluoride containing free hydrofluoric acid. Advantageously the aqueous solution of uranyl fluoride is obtained by dissolving uranium hexafluoride in water. On electrolysis, the uranyl ions are reduced to uranous tons at the cathode and immediately combine with the fluoride ions in solution to form the insoluble uranium tetrafluoride which is precipitated.

  10. Electrolyte vapor condenser

    DOEpatents

    Sederquist, Richard A.; Szydlowski, Donald F.; Sawyer, Richard D.

    1983-01-01

    A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well.

  11. Electrolyte vapor condenser

    DOEpatents

    Sederquist, R.A.; Szydlowski, D.F.; Sawyer, R.D.

    1983-02-08

    A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well. 3 figs.

  12. Vapor Pressure of Aqueous Solutions of Electrolytes Reproduced with Coarse-Grained Models without Electrostatics.

    PubMed

    Perez Sirkin, Yamila A; Factorovich, Matías H; Molinero, Valeria; Scherlis, Damian A

    2016-06-14

    The vapor pressure of water is a key property in a large class of applications from the design of membranes for fuel cells and separations to the prediction of the mixing state of atmospheric aerosols. Molecular simulations have been used to compute vapor pressures, and a few studies on liquid mixtures and solutions have been reported on the basis of the Gibbs Ensemble Monte Carlo method in combination with atomistic force fields. These simulations are costly, making them impractical for the prediction of the vapor pressure of complex materials. The goal of the present work is twofold: (1) to demonstrate the use of the grand canonical screening approach ( Factorovich , M. H. J. Chem. Phys. 2014 , 140 , 064111 ) to compute the vapor pressure of solutions and to extend the methodology for the treatment of systems without a liquid-vapor interface and (2) to investigate the ability of computationally efficient high-resolution coarse-grained models based on the mW monatomic water potential and ions described exclusively with short-range interactions to reproduce the relative vapor pressure of aqueous solutions. We find that coarse-grained models of LiCl and NaCl solutions faithfully reproduce the experimental relative pressures up to high salt concentrations, despite the inability of these models to predict cohesive energies of the solutions or the salts. A thermodynamic analysis reveals that the coarse-grained models achieve the experimental activity coefficients of water in solution through a compensation of severely underestimated hydration and vaporization free energies of the salts. Our results suggest that coarse-grained models developed to replicate the hydration structure and the effective ion-ion attraction in solution may lead to this compensation. Moreover, they suggest an avenue for the design of coarse-grained models that accurately reproduce the activity coefficients of solutions. PMID:27196963

  13. A comparison of traditional and quantitative analysis of acid-base and electrolyte imbalances in horses with gastrointestinal disorders.

    PubMed

    Navarro, Marga; Monreal, Luis; Segura, Dídac; Armengou, Lara; Añor, Sònia

    2005-01-01

    The purpose of this study was to compare traditional and quantitative approaches in analysis of the acid-base and electrolyte imbalances in horses with acute gastrointestinal disorders. Venous blood samples were collected from 115 colic horses, and from 45 control animals. Horses with colic were grouped according to the clinical diagnosis into 4 categories: obstructive, ischemic, inflammatory, and diarrheic problems. Plasma electrolytes, total protein, albumin, pH, pCO2, tCO2, HCO3-, base excess, anion gap, measured strong ion difference (SIDm), nonvolatile weak buffers (A(tot)), and strong ion gap were determined in all samples. All colic horses revealed a mild but statistically significant decrease in iCa2+ concentration. Potassium levels were mildly but significantly decreased in horses with colic, except in those within the inflammatory group. Additionally, the diarrheic group revealed a mild but significant decrease in Na+, tCa, tMg, total protein, albumin, SIDm, and A(tot). Although pH was not severely altered in any colic group, 26% of the horses in the obstructive group, 74% in the ischemic group, 87% in the inflammatory group, and 22% in the diarrheic group had a metabolic imbalance. In contrast, when using the quantitative approach, 78% of the diarrheic horses revealed a metabolic imbalance consisting mainly of a strong ion acidosis and nonvolatile buffer ion alkalosis. In conclusion, mild acid-base and electrolyte disturbances were observed in horses with gastrointestinal disorders. However, the quantitative approach should be used in these animals, especially when strong ion imbalances and hypoproteinemia are detected, so that abnormalities in acid-base status are evident. PMID:16355683

  14. 137Cs desorption from lichen using acid solutions

    NASA Astrophysics Data System (ADS)

    Čučulović, A. A.; Veselinović, D.; Miljanić, S. S.

    2009-09-01

    Desoprtion of 137Cs from samples of Cetraria islandica lichen using HCl ( A) and HNO3 ( B) acid solutions with pH values from 2.00 to 3.75 was investigated. After five consecutive desorptions lasting 24 h it was shown that between 52.2% (solution B pH 3.28) and 72.2% (solution A pH 2.00) of 137Cs was desorbed from the lichen and the initial desorptions were the most successful. Lichen desorbed with the stated solutions did not undergo structural changes. The amount of absorbed water from solutions A and B, used for desorption from lichen, in relation to the starting volume (expressed in %) showed that solution concentration did not take place. Lichen act as neutralizing agents because the pH of the lichen thallus is higher than the pH value of the solution used

  15. Determination of nitric acid in highly radioactive solutions by the method of coulometric titration

    SciTech Connect

    Gromov, V.S.; Kuperman, A.Ya.; Smirnov, Yu.A.

    1988-11-01

    A procedure, a cell, and an electronic block have been developed for a long-distance determination of nitric acid in highly radioactive industrial solutions by coulometric titration under hot chamber conditions. A solution of a mixture of ammonium and potassium oxalates was used for the background and anoide electrolytes. This solution prevents the hydrolysis of the metal ions and appreciably decreases the rate of accumulation of the acid in the anode chamber of the cell. Titration with 0.1-0.5 A currents is carried out with internal generation of hydroxyl ions. The cell was prepared from a radiation-resistant and transparent material, poly(methyl methacrylate). The anode and cathode chambers were separated by a cellophane membrane, reinforced by a porous glass filter. By using the electronic coulometric block working together with a pH-meter (EV-74 or I-130) and with an automatic titration block (BAT-15), the titration can be carried out automatically, and the determination results can be obtained in a digital form.

  16. Effect of Magnesium Ion on the Zinc Electrodeposition from Acidic Sulfate Electrolyte

    NASA Astrophysics Data System (ADS)

    Tian, Lin; Xie, Gang; Yu, Xiao-Hua; Li, Rong-Xing; Zeng, Gui-Sheng

    2012-02-01

    The effects of Mg2+ ion on the zinc electrodeposition were systematically investigated in sulfuric acid solution through the characterizations of current efficiency (CE), power consumption (PC), deposit morphology, cathodic polarization, and cyclic voltammetry. The results demonstrate that there is no significant influence on CE and PC in the Mg2+ concentration range of 1 to 10 g L-1, but with a drastic decrease of the CE and rapid increase of PC at Mg2+ ion concentration above 15 g L-1. Based on the morphology observation and polarization curves, the presence of Mg2+ ions could also induce the coarse surface on the electrodeposited zinc accompanying the enhancement of the cathodic polarization, which becomes more distinct at a high concentration above 15 g L-1. Furthermore, hydrogen evolution could be promoted with the existence of Mg2+ ions according to cyclic voltammograms.

  17. Effects of electrolyte and nutrient solutions on performance and metabolic balance.

    PubMed

    Johnson, H L; Nelson, R A; Consolazio, C F

    1988-02-01

    Three commercial sport drinks, solutions of their individual minerals and glucose, and water were used to maintain water balances in six men during 4 h of physical activity in a 35 degrees C room. Each solution was provided for 5 consecutive days to each man during the 12-wk study. Complete mineral and water balances (including sweat losses) were conducted. Oxygen consumption and carbon dioxide production were measured during two levels of sub-maximal and during a maximal treadmill performance test. All of the solutions, including water, were equally effective in maintaining water and mineral balances, and moderate physical performance while the men were consuming an adequate all liquid diet. All of the solutions containing carbohydrates increased respiratory exchange ratios. These increases were significant during maximal performance for only two of the commercial products. These two products also produced the higher values for most of the performance evaluations, although they were not generally significantly different from values obtained while other solutions or water were consumed. The major benefit of these commercial sport drinks are their prevention of hypohydration due to an increase in voluntary fluid intakes. PMID:3343913

  18. Titratable macroions in multivalent electrolyte solutions: Strong coupling dressed ion approach

    NASA Astrophysics Data System (ADS)

    Adžić, Nataša; Podgornik, Rudolf

    2016-06-01

    We present a theoretical description of the effect of polyvalent ions on the interaction between titratable macroions. The model system consists of two point-like macroions with dissociable sites, immersed in an asymmetric ionic mixture of monovalent and polyvalent salts. We formulate a dressed ion strong coupling theory, based on the decomposition of the asymmetric ionic mixture into a weakly electrostatically coupled monovalent salt and into polyvalent ions that are strongly electrostatically coupled to the titratable macro-ions. The charge of the macroions is not considered as fixed, but is allowed to respond to local bathing solution parameters (electrostatic potential, pH of the solution, and salt concentration) through a simple charge regulation model. The approach presented, yielding an effective polyvalent-ion mediated interaction between charge-regulated macroions at various solution conditions, describes the strong coupling equivalent of the Kirkwood-Schumaker interaction.

  19. In situ STM studies of Sb(111) electrodes in aqueous electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Grozovski, V.; Kallip, S.; Lust, E.

    2013-07-01

    The in situ STM studies of Sb(111), which was cleaved at the temperature of liquid nitrogen inside the glove box, and of Sb(111), which was electrochemically polished in the KI + HCl aqueous solution, have been performed under negative polarizations from - 0.8 to - 0.15 V (versus Ag|AgCl in sat. KCl aqueous solution) in the 0.5 M Na2SO4 + 0.0003 M H2SO4 aqueous solution. The atomic resolution has been achieved. The in situ STM data show that there are no quick surface reconstruction processes and the surface structure of cleaved and electrochemically polished Sb(111) is stable within the potential region investigated, similarly for Bi(111) single crystal electrode, previously studied [S. Kallip, E. Lust, Electrochem. Comm. 7 (2005) 863].

  20. Nanobubble clusters of dissolved gas in aqueous solutions of electrolyte. I. Experimental proof

    NASA Astrophysics Data System (ADS)

    Bunkin, N. F.; Shkirin, A. V.; Ignatiev, P. S.; Chaikov, L. L.; Burkhanov, I. S.; Starosvetskij, A. V.

    2012-08-01

    Results of experiments with dynamic light scattering, phase microscopy, and polarimetric scatterometry allow us to claim that long-living gas nanobubbles and the clusters composed of such nanobubbles are generated spontaneously in an aqueous solution of salt, saturated with dissolved gas (say, atmospheric air). The characteristic sizes of both nanobubbles and their clusters are found by solving the inverse problem of optical wave scattering in ionic solutions. These experimental results develop our earlier study reported by Bunkin et al. [J. Chem. Phys. 130, 134308 (2009)], 10.1063/1.3095476 and can be treated as evidence for the special role of ions in the generation and stabilization of gas nanobubbles.

  1. Dephosphorization of Steelmaking Slag by Leaching with Acidic Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Qiao, Yong; Diao, Jiang; Liu, Xuan; Li, Xiaosa; Zhang, Tao; Xie, Bing

    2015-12-01

    In the present paper, dephosphorization of steelmaking slag by leaching with acidic aqueous solution composed of citric acid, sodium hydroxide, hydrochloric acid and ion-exchanged water was investigated. The buffer solution of C6H8O7-NaOH-HCl system prevented changes in the pH values. Kinetic parameters including leaching temperature, slag particle size and pH values of the solution were optimized. The results showed that temperature has no obvious effect on the dissolution ratio of phosphorus. However, it has a significant effect on the dissolution ratio of iron. The dephosphorization rate increases with the decrease of slag particle size and the pH value of the solution. Over 90% of the phosphorus can be dissolved in the solution while the corresponding leaching ratio of iron was only 30% below the optimal condition. Leaching kinetics of dephosphorization follow the unreacted shrinking core model with a rate controlled step by the solid diffusion layer, the corresponding apparent activation energy being 1.233 kJ mol-1. A semiempirical kinetic equation was established. After leaching, most of the nC2S-C3P solid solution in the steelmaking slag was selectively dissolved in the aqueous solution and the iron content in the solid residue was correspondingly enriched.

  2. Testing of the GROMOS Force-Field Parameter Set 54A8: Structural Properties of Electrolyte Solutions, Lipid Bilayers, and Proteins.

    PubMed

    Reif, Maria M; Winger, Moritz; Oostenbrink, Chris

    2013-02-12

    The GROMOS 54A8 force field [Reif et al. J. Chem. Theory Comput.2012, 8, 3705-3723] is the first of its kind to contain nonbonded parameters for charged amino acid side chains that are derived in a rigorously thermodynamic fashion, namely a calibration against single-ion hydration free energies. Considering charged moieties in solution, the most decisive signature of the GROMOS 54A8 force field in comparison to its predecessor 54A7 can probably be found in the thermodynamic equilibrium between salt-bridged ion pair formation and hydration. Possible shifts in this equilibrium might crucially affect the properties of electrolyte solutions or/and the stability of (bio)molecules. It is therefore important to investigate the consequences of the altered description of charged oligoatomic species in the GROMOS 54A8 force field. The present study focuses on examining the ability of the GROMOS 54A8 force field to accurately model the structural properties of electrolyte solutions, lipid bilayers, and proteins. It is found that (i) aqueous electrolytes involving oligoatomic species (sodium acetate, methylammonium chloride, guanidinium chloride) reproduce experimental salt activity derivatives for concentrations up to 1.0 m (1.0-molal) very well, and good agreement between simulated and experimental data is also reached for sodium acetate and methylammonium chloride at 2.0 m concentration, while not even qualitative agreement is found for sodium chloride throughout the whole range of examined concentrations, indicating a failure of the GROMOS 54A7 and 54A8 force-field parameter sets to correctly account for the balance between ion-ion and ion-water binding propensities of sodium and chloride ions; (ii) the GROMOS 54A8 force field reproduces the liquid crystalline-like phase of a hydrated DPPC bilayer at a pressure of 1 bar and a temperature of 323 K, the area per lipid being in agreement with experimental data, whereas other structural properties (volume per lipid, bilayer

  3. Testing of the GROMOS Force-Field Parameter Set 54A8: Structural Properties of Electrolyte Solutions, Lipid Bilayers, and Proteins

    PubMed Central

    2013-01-01

    The GROMOS 54A8 force field [Reif et al. J. Chem. Theory Comput.2012, 8, 3705–3723] is the first of its kind to contain nonbonded parameters for charged amino acid side chains that are derived in a rigorously thermodynamic fashion, namely a calibration against single-ion hydration free energies. Considering charged moieties in solution, the most decisive signature of the GROMOS 54A8 force field in comparison to its predecessor 54A7 can probably be found in the thermodynamic equilibrium between salt-bridged ion pair formation and hydration. Possible shifts in this equilibrium might crucially affect the properties of electrolyte solutions or/and the stability of (bio)molecules. It is therefore important to investigate the consequences of the altered description of charged oligoatomic species in the GROMOS 54A8 force field. The present study focuses on examining the ability of the GROMOS 54A8 force field to accurately model the structural properties of electrolyte solutions, lipid bilayers, and proteins. It is found that (i) aqueous electrolytes involving oligoatomic species (sodium acetate, methylammonium chloride, guanidinium chloride) reproduce experimental salt activity derivatives for concentrations up to 1.0 m (1.0-molal) very well, and good agreement between simulated and experimental data is also reached for sodium acetate and methylammonium chloride at 2.0 m concentration, while not even qualitative agreement is found for sodium chloride throughout the whole range of examined concentrations, indicating a failure of the GROMOS 54A7 and 54A8 force-field parameter sets to correctly account for the balance between ion–ion and ion–water binding propensities of sodium and chloride ions; (ii) the GROMOS 54A8 force field reproduces the liquid crystalline-like phase of a hydrated DPPC bilayer at a pressure of 1 bar and a temperature of 323 K, the area per lipid being in agreement with experimental data, whereas other structural properties (volume per lipid

  4. γ-Irradiation of malic acid in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Negron-Mendoza, Alicia; Graff, Rebecca L.; Ponnamperuma, Cyril

    1980-12-01

    The γ-irradiation of malic acid in aqueous solutions was studied under initially oxygenated and oxygen-free conditions in an attempt to determine the possible interconversion of malic acid into other carboxylic acids, specifically those associated with Krebs cycle. The effect of dose on product formation of the system was investigated. Gas-liquid chromatography combined with mass spectrometry was used as the principal means of identification of the non-volatile products. Thin layer chromotography and direct probe mass spectroscopy were also employed. The findings show that a variety of carboxylic acids are formed, with malonic and succinic acids in greatest abundance. These products have all been identified as being formed in the γ-irradiation of acetic acid, suggesting a common intermediary. Since these molecules fit into a metabolic cycle, it is strongly suggestive that prebiotic pathways provided the basis for biological systems.

  5. Ion Association versus Ion Interaction Models in Examining Electrolyte Solutions: Application to Calcium Hydroxide Solubility Equilibrium

    ERIC Educational Resources Information Center

    Menéndez, M. Isabel; Borge, Javier

    2014-01-01

    The heterogeneous equilibrium of the solubility of calcium hydroxide in water is used to predict both its solubility product from solubility and solubility values from solubility product when inert salts, in any concentration, are present. Accepting the necessity of including activity coefficients to treat the saturated solution of calcium…

  6. Protein-protein and protein-salt interactions in aqueous protein solutions containing concentrated electrolytes

    SciTech Connect

    Curtis, R.A.; Blanch, H.W.; Prausnitz, J.M.

    1998-01-05

    Protein-protein and protein-salt interactions have been obtained for ovalbumin in solutions of ammonium sulfate and for lysozyme in solutions of ammonium sulfate, sodium chloride, potassium isothiocyanate, and potassium chloride. The two-body interactions between ovalbumin molecules in concentrated ammonium-sulfate solutions can be described by the DLVO potentials plus a potential that accounts for the decrease in free volume available to the protein due to the presence of the salt ions. The interaction between ovalbumin and ammonium sulfate is unfavorable, reflecting the kosmotropic nature of sulfate anions. Lysozyme-lysozyme interactions cannot be described by the above potentials because anion binding to lysozyme alters these interactions. Lysozyme-isothiocyanate complexes are strongly attractive due to electrostatic interactions resulting from bridging by the isothiocyanate ion. Lysozyme-lysozyme interactions in sulfate solutions are more repulsive than expected, possibly resulting from a larger excluded volume of a lysozyme-sulfate bound complex or perhaps, hydration forces between the lysozyme-sulfate complexes.

  7. Urinary excretion of polyethylene glycol 3350 and sulfate after gut lavage with a polyethylene glycol electrolyte lavage solution.

    PubMed

    Brady, C E; DiPalma, J A; Morawski, S G; Santa Ana, C A; Fordtran, J S

    1986-06-01

    Ingestion of an electrolyte lavage solution containing polyethylene glycol 3350 and sulfate is an effective method of cleansing the colon for diagnostic studies. Polyethylene glycol and sulfate are considered poorly absorbed from the gastrointestinal tract. Because of the quantities administered, concern exists about potential toxicity of absorption of even a small percentage, particularly for polyethylene glycol. We measured the urinary excretion of both polyethylene glycol and sulfate in normal subjects and inflammatory bowel patients. Absorption of polyethylene glycol can be assessed by measuring recovery in urine, as 85%-96% of an intravenous load is excreted in urine. Similarly, appreciable sulfate absorption would exceed renal tubular reabsorption and result in increased urinary excretion. Mean percent polyethylene glycol load recovered in urine was minimal and similar for normal (0.06%) and inflammatory bowel (0.09%) subjects. Urinary sulfate excretion after lavage was also similar for both groups and was not different from baseline. These results do not suggest the likelihood of toxicity due to polyethylene glycol 3350 or sulfate absorption during gut lavage with this solution. PMID:3699408

  8. Highly accurate boronimeter assay of concentrated boric acid solutions

    SciTech Connect

    Ball, R.M. )

    1992-01-01

    The Random-Walk Boronimeter has successfully been used as an on-line indicator of boric acid concentration in an operating commercial pressurized water reactor. The principle has been adapted for measurement of discrete samples to high accuracy and to concentrations up to 6000 ppm natural boron in light water. Boric acid concentration in an aqueous solution is a necessary measurement in many nuclear power plants, particularly those that use boric acid dissolved in the reactor coolant as a reactivity control system. Other nuclear plants use a high-concentration boric acid solution as a backup shutdown system. Such a shutdown system depends on rapid injection of the solution and frequent surveillance of the fluid to ensure the presence of the neutron absorber. The two methods typically used to measure boric acid are the chemical and the physical methods. The chemical method uses titration to determine the ionic concentration of the BO[sub 3] ions and infers the boron concentration. The physical method uses the attenuation of neutrons by the solution and infers the boron concentration from the neutron absorption properties. This paper describes the Random-Walk Boronimeter configured to measure discrete samples to high accuracy and high concentration.

  9. Polymerization of Pu(IV) in aqueous nitric acid solutions

    SciTech Connect

    Toth, L.M.; Friedman, H.A.; Osborne, M.M.

    1980-10-01

    The polymerization of Pu(IV) in aqueous nitric acid solutions has been studied spectrophotometrically both to establish the influence of large UO{sub 2}(NO{sub 3}){sub 2} concentrations on the polymerization rates and, more generally, to review the influence of the major parameters on the polymer reaction. Typically, experiments have been performed at 50{sup 0}C and with 0.05 M Pu in nitric acid solutions that vary in acidity from 0.07 to 0.4 M. An induction period usually precedes the polymer growth stage during which time nucleation of primary hydrolysis products occurs. Uranyl nitrate retards the polymerization reaction by approximately 35% in spite of the counteracting influence of the nitrate ions associated with this solute. The rate of polymer formation, expressed as d(percent polymer)/dt, has been shown to depend on the total plutonium concentration in reactions where the Pu(IV) concentration remained constant; and it is therefore suggested that the polymer reaction rate is not first order with respect to the concentration of plutonium as was previously thought. It has been shown further that accurate acid determinations on stock reagents are essential in order to obtain reliable polymerization experiments. Satisfactory procedures for these analyses did not exist, so appropriate modifications to the iodate precipitation methods were developed. The most ideal plutonium reagent material has been shown to be crystalline Pu(IV) nitrate because it can be added directly to acid solutions without the occurrence of unintentional hydrolysis reactions.

  10. Casimir force in a critical film formed from an electrolytic solution.

    PubMed

    Mukhopadhyay, A; Law, B M

    2001-04-01

    We have studied the thickness of vapor adsorbed films of the critical binary liquid mixture acetic acid plus nonane adsorbed onto a silicon wafer substrate as a function of temperature near the critical temperature. This critical film possesses opposite boundary conditions (+-) at its two surfaces and, due to the dissociation of acetic acid, both the electrostatic force and the dispersion force affect the adsorbed film thickness. On approaching the critical temperature T(c), an increase in the film thickness L is observed, implying that the sign of the universal Casimir amplitude Delta(+-) is positive, consistent with theoretical predictions. However, we find quantitative discrepancies in the value of Delta(+-) and the form of the critical Casimir pressure scaling function vartheta(+-) compared with previous experimental results. We attribute these discrepancies to the complex nature of the critical system studied in this experiment. PMID:11308860

  11. Solubility of NaCl in aqueous electrolyte solutions from 10 to 100°C

    USGS Publications Warehouse

    Clynne, M.A.; Potter, R.W., II; Haas, J.L., Jr.

    1981-01-01

    The solubilities of NaCl in aqueous KCl, MgCl2, CaCl2, and mixed CaCl2-KCl solutions have been determined from 10 to 100??C. The data were fit to an equation, and the equation was used to calculate values of the change in solubility of NaCl, ???[NaCl]/???T. These values are required for calculations of the rate of migration of fluids in a thermal gradient in rock salt. The data obtained here indicate that the values of ???[NaCl]/???T are 36-73% greater for solutions containing divalent ions than for the NaCl-H2O system.

  12. Graphene quantum dots as the electrolyte for solid state supercapacitors

    PubMed Central

    Zhang, Su; Li, Yutong; Song, Huaihe; Chen, Xiaohong; Zhou, Jisheng; Hong, Song; Huang, Minglu

    2016-01-01

    We propose that graphene quantum dots (GQDs) with a sufficient number of acidic oxygen-bearing functional groups such as -COOH and -OH can serve as solution- and solid- type electrolytes for supercapacitors. Moreover, we found that the ionic conductivity and ion-donating ability of the GQDs could be markedly improved by simply neutralizing their acidic functional groups by using KOH. These neutralized GQDs as the solution- or solid-type electrolytes greatly enhanced the capacitive performance and rate capability of the supercapacitors. The reason for the enhancement can be ascribed to the fully ionization of the weak acidic oxygen-bearing functional groups after neutralization. PMID:26763275

  13. A growth mechanism of porous film formed on Al in 0.6 M oxalic acid electrolyte.

    PubMed

    Han, Seong Ho; Kim, Hyoung Chan

    2012-04-01

    Understanding of mechanism of porous film formation is of fundamental importance for anodizing in general because, the onset of pore initiation terminates the barrier film growth process over the macroscopic metal surface. Several mechanisms have been proposed to explain pore formation. They include direct injection of aluminum ions into electrolyte and a field-assisted dissolution mechanism. High-resolution scanning electron microscopy of anodized surfaces and direct TEM of ion beam thinned films and ultrarmicrotomed film sections have been employed to gain further insight into the mechanism of initial porous film growth in 0.6 M oxalic acid. From detailed examination of the behavior of the xenon-tagged layer in the film during pore initiation and development in oxalic acid, the film structure of the barrier layer is found to be unstable during pore initiation and the instability of the film structure is possibly related to the field-assisted structure modification process. PMID:22849190

  14. The effect of porosity on performance of phosphoric acid doped polybenzimidazole polymer electrolyte membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Celik, Muhammet; Genc, Gamze; Elden, Gulsah; Yapici, Huseyin

    2016-03-01

    A polybenzimidazole (PBI) based polymer electrolyte fuel cells, which called high temperature polymer electrolyte fuel cells (HT-PEMS), operate at higher temperatures (120-200°C) than conventional PEM fuel cells. Although it is known that HT-PEMS have some of the significant advantages as non-humidification requirements for membrane and the lack of liquid water at high temperature in the fuel cell, the generated water as a result of oxygen reduction reaction causes in the degradation of these systems. The generated water absorbed into membrane side interacts with the hydrophilic PBI matrix and it can cause swelling of membrane, so water transport mechanism in a membrane electrode assembly (MEA) needs to be well understood and water balance must be calculated in MEA. Therefore, the water diffusion transport across the electrolyte should be determined. In this study, various porosity values of gas diffusion layers are considered in order to investigate the effects of porosity on the water management for two phase flow in fuel cell. Two-dimensional fuel cell with interdigitated flow-field is modelled using COMSOL Multiphysics 4.2a software. The operating temperature and doping level is selected as 160°C and 6.75mol H3PO4/PBI, respectively.

  15. A Randomized Controlled Trial Evaluating a Low-Volume PEG Solution Plus Ascorbic Acid versus Standard PEG Solution in Bowel Preparation for Colonoscopy

    PubMed Central

    Tajika, Masahiro; Tanaka, Tsutomu; Ishihara, Makoto; Mizuno, Nobumasa; Hara, Kazuo; Hijioka, Susumu; Imaoka, Hiroshi; Sato, Takamitsu; Yogi, Tatsuji; Tsutsumi, Hideharu; Fujiyoshi, Toshihisa; Hieda, Nobuhiro; Okuno, Nozomi; Yoshida, Tsukasa; Bhatia, Vikram; Yatabe, Yasushi; Yamao, Kenji; Niwa, Yasumasa

    2015-01-01

    Evaluation of polyethylene glycol electrolyte lavage solution containing ascorbic acid (PEG-ASC) has been controversial in the point of its hyperosmolarity, especially in old population. So we therefore designed the present study to compare the efficacy, acceptability, tolerability, and safety of 1.5 L PEG+ASC and 2 L standard PEG electrolyte solution (PEG-ELS), not only in the general population, but also in patients of advanced age. Randomization was stratified by age (<70 years or 70> years), and hematological and biochemical parameters were compared in each age group, especially with respect to the safety profile of each regimen. As a result, the 1.5-L PEG-ASC regimen had higher patient acceptability than the 2-L PEG-ELS regimen. Tolerability, bowel cleansing, and safety were similar between regimens. However, we demonstrated significant statistical changes in the hematological and biochemical parameters after taking bowel preparation solutions, not only in the PEG+ASC group, but also in the PEG-ELS group. No significant differences in the safety profile were found between subjects aged less than 70 years and those aged 70 years or more; nevertheless, regardless of age, proper hydration is needed throughout the bowel preparation process. PMID:26649036

  16. Methanol Uptake by Low Temperature Aqueous Sulfuric Acid Solutions

    NASA Technical Reports Server (NTRS)

    Iraci, L. T.; Essin, A. M.; Golden, D. M.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    The global methanol budget is currently unbalanced, with source terms significantly larger than the sinks terms. To evaluate possible losses of gaseous methanol to sulfate aerosols, the solubility and reactivity of methanol in aqueous sulfuric acid solutions representative of upper tropospheric and lower stratospheric aerosols is under investigation. Methanol will partition into sulfate aerosols according to its Henry's law solubility. Using standard uptake techniques in a Knudsen cell reactor, we have measured the effective Henry's law coefficient, H*, for cold (196 - 220 K) solutions ranging between 45 and 70 wt % H2SO4. We have found that methanol solubility ranges from approx. 10(exp 5) - 10(exp 7) M/atm for UT/LS conditions. Solubility increases with decreasing temperature and with increasing sulfuric acid content. Although methanol is slightly more soluble than are acetone and formaldehyde, current data indicate that uptake by clean aqueous sulfuric acid particles will not be a significant sink for methanol in the UT/LS. These solubility measurements include uptake due to physical solvation and any rapid equilibria which are established in solution. Reaction between primary alcohols and sulfuric acid does occur, leading to the production of alkyl sulfates. Literature values for the rate of this reaction suggest that formation of CH3OSO3H is not significant over our experimental time scale for solutions below 80 wt % H2SO4. To confirm this directly, results obtained using a complementary equilibrium measurement technique will also be presented.

  17. [Investigation on mechanism of pyrite oxidation in acidic solutions].

    PubMed

    Wang, Nan; Yi, Xiao-Yun; Dang, Zhi; Liu, Yun

    2012-11-01

    The mechanism of pyrite oxidation in acidic solutions was investigated by electrochemical analysis methods, such as open-circuit potential, cyclic voltammetry, Tafel polarization curve and anodic polarization curve, using a pyrite-carbon paste electrode as working electrode. The results showed that the oxidation process of pyrite in acidic solutions was via a two-step reaction: the first step was the dissolution of iron moiety and formation of a passivation film composed of elemental sulphur, metal-deficient sulfide and polysulfide; the second step was the further oxidation of these intermediate products to SO4(2-). The final reaction products of pyrite oxidation were Fe3+ and SO4(2-) in acidic solutions. In addition, the open-circuit potential and corrosion potential were positively shifted, the peak current and the corrosion current were increased with the increase in concentration of H2SO4 solutions. This indicated that increased acidity of the system was advantageous to the oxidation of pyrite. PMID:23323425

  18. Lowering the platinum loading of high temperature polymer electrolyte membrane fuel cells with acid doped polybenzimidazole membranes

    NASA Astrophysics Data System (ADS)

    Martin, S.; Li, Q.; Jensen, J. O.

    2015-10-01

    Membrane electrode assemblies (MEAs) with ultra-low Pt loading electrodes were prepared for high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) based on acid doped polybenzimidazole. With no electrode binders or ionomers, the triple phase boundary of the catalyst layer was established by the acid transfer from the acid doped membrane to the electrodes and can therefore be tailored by using catalysts with varied Pt to C ratios. With a loading of ca. 0.1 mgPtcm-2 on each electrode the best performance was obtained with electrodes prepared from 10 wt.% Pt/C due to the improved Pt dispersion, extended triple phase boundary upon the acid transfer and the alleviated acid flooding of the catalytic layer. The MEA delivered a peak power density of 482 mW cm-2 for H2/O2 and 321 mW cm-2 for H2/air, corresponding to an overall Pt utilization of 2.5 and 1.7 kW gPt-1, respectively. The durability test revealed no net voltage decay during more than 1700 h of uninterrupted operation at 200 mA cm-2 and 160 °C.

  19. Preparation and electrochemical properties of gel polymer electrolytes using triethylene glycol diacetate-2-propenoic acid butyl ester copolymer for high energy density lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Fan, Huanhuan; Li, Hongxiao; Fan, Li-Zhen; Shi, Qiao

    2014-03-01

    Gel polymer electrolytes (GPE) composed of triethylene glycol diacetate (TEGDA)-2-propenoic acid butyl ester (BA) copolymer and commercial used liquid organic electrolyte are prepared via in situ polymerization. The ionic conductivity of the as-prepared GPE can reach 5.5 × 10-3 S cm-1 with 6 wt% monomers and 94 wt% liquid electrolyte at 25 °C. Additionally, the temperature dependence of the ionic conductivity is consistent with an Arrhenius temperature behavior in a temperature range of 20-90 °C. Furthermore, the electrochemical stability window of the GPE is 5 V at 25 °C. A Li|GPE|(Li[Li1/6Ni1/4Mn7/12]O2) cell has been fabricated, which shows good charge-discharge properties and stable cycle performance compared to liquid electrolyte under the same test conditions.

  20. Solid polymer electrolyte from phosphorylated chitosan

    SciTech Connect

    Fauzi, Iqbal Arcana, I Made

    2014-03-24

    Recently, the need of secondary battery application continues to increase. The secondary battery which using a liquid electrolyte was indicated had some weakness. A solid polymer electrolyte is an alternative electrolytes membrane which developed in order to replace the liquid electrolyte type. In the present study, the effect of phosphorylation on to polymer electrolyte membrane which synthesized from chitosan and lithium perchlorate salts was investigated. The effect of the component’s composition respectively on the properties of polymer electrolyte, was carried out by analyzed of it’s characterization such as functional groups, ion conductivity, and thermal properties. The mechanical properties i.e tensile resistance and the morphology structure of membrane surface were determined. The phosphorylation processing of polymer electrolyte membrane of chitosan and lithium perchlorate was conducted by immersing with phosphoric acid for 2 hours, and then irradiated on a microwave for 60 seconds. The degree of deacetylation of chitosan derived from shrimp shells was obtained around 75.4%. Relative molecular mass of chitosan was obtained by viscometry method is 796,792 g/mol. The ionic conductivity of chitosan membrane was increase from 6.33 × 10{sup −6} S/cm up to 6.01 × 10{sup −4} S/cm after adding by 15 % solution of lithium perchlorate. After phosphorylation, the ionic conductivity of phosphorylated lithium chitosan membrane was observed 1.37 × 10{sup −3} S/cm, while the tensile resistance of 40.2 MPa with a better thermal resistance. On the strength of electrolyte membrane properties, this polymer electrolyte membrane was suggested had one potential used for polymer electrolyte in field of lithium battery applications.

  1. Transport properties of long straight nano-channels in electrolyte solutions: a systematic approach.

    PubMed

    Yaroshchuk, Andriy E

    2011-10-14

    The principle of local thermodynamic equilibrium is systematically employed for obtaining various transport properties of long straight nano-channels. The concept of virtual solution is used to describe situations of non-negligible overlap of diffuse parts of electric double layers (EDLs) in nano-channels. Generic expressions for a variety of transport properties of long straight nano-channels are obtained in terms of quasi-equilibrium distribution coefficients of ions and functionals of quasi-equilibrium distribution of electrostatic potential. Further, the Poisson-Boltzmann approach is used to specify these expressions for long straight slit-like nano-channels. In the approximation of non-overlapped diffuse parts of double electric layers in nano-channels, simple analytical expressions are obtained for the apparent electrophoretic mobilities of (trace) analytes of arbitrary charge as well as for the salt reflection coefficient (osmotic pressure), salt diffusion permeability and electro-viscosity (electrokinetic energy conversion). The approximate solutions are compared with the results of rigorous solution of non-linearized Poisson-Boltzmann equation, and the accuracy of approximation is shown to be typically excellent when the nano-channel half-height exceeds ca.3 Debye screening lengths. Due to non-negligible electrostatic adsorption of ions by nano-channels, the apparent electrophoretic mobilities of counter-ionic analytes in nano-channels are smaller than in micro-channels whereas those of co-ionic analytes are larger. This dependence on the charge is useful for the separation of analytes of close electrophoretic mobilities. The osmotic pressure is shown to be positive, negative or pass through maxima as a function of applied salt-concentration difference within a fairly narrow range of ratios of nano-channel height to the Debye screening length. The diffusion permeability of charged nano-channels to single salts is demonstrated (for the first time) to be

  2. Titania nanotubes from weak organic acid electrolyte: fabrication, characterization and oxide film properties.

    PubMed

    Munirathinam, Balakrishnan; Neelakantan, Lakshman

    2015-04-01

    In this study, TiO2 nanotubes were fabricated using anodic oxidation in fluoride containing weak organic acid for different durations (0.5h, 1h, 2h and 3h). Scanning electron microscope (SEM) micrographs reveal that the morphology of titanium oxide varies with anodization time. Raman spectroscopy and X-ray diffraction (XRD) results indicate that the as-formed oxide nanotubes were amorphous in nature, yet transform into crystalline phases (anatase and rutile) upon annealing at 600°C. Wettability measurements show that both as-formed and annealed nanotubes exhibited hydrophilic behavior. The electrochemical behavior was ascertained by DC polarization and AC electrochemical impedance spectroscopy (EIS) measurements in 0.9% NaCl solution. The results suggest that the annealed nanotubes showed higher impedance (10(5)-10(6)Ωcm(2)) and lower passive current density (10(-7)Acm(-2)) than the as-formed nanotubes. In addition, we investigated the influence of post heat treatment on the semiconducting properties of the oxides by capacitance measurements. In vitro bioactivity test in simulated body fluid (SBF) showed that precipitation of Ca/P is easier in crystallized nanotubes than the amorphous structure. Our study uses a simple strategy to prepare nano-structured titania films and hints the feasibility of tailoring the oxide properties by thermal treatment, producing surfaces with better bioactivity. PMID:25686985

  3. Nanofiltration of Electrolyte Solutions by Sub-2nm Carbon Nanotube Membranes

    SciTech Connect

    Fornasiero, F; Park, H G; Holt, J K; Stadermann, M; Kim, S; In, J B; Grigoropoulos, C P; Noy, A; Bakajin, O

    2008-03-13

    Both MD simulations and experimental studies have shown that liquid and gas flow through carbon nanotubes with nanometer size diameter is exceptionally fast. For applications in separation technology, selectivity is required together with fast flow. In this work, we use pressure-driven filtration experiments to study ion exclusion in silicon nitride/sub-2-nm CNT composite membranes as a function of solution ionic strength, pH, and ion valence. We show that carbon nanotube membranes exhibit significant ion exclusion at low salt concentration. Our results support a rejection mechanism dominated by electrostatic interactions between fixed membrane charges and mobile ions, while steric and hydrodynamic effects appear to be less important. Comparison with commercial nanofiltration membranes for water softening reveals that our carbon nanotube membranes provides far superior water fluxes for similar ion rejection capabilities.

  4. Oxygen reduction in fuel cell electrolytes

    SciTech Connect

    Striebel, K.A.

    1987-01-01

    Voltage losses in the O{sub 2} cathode represent the major inefficiency in aqueous fuel cells for transportation or stationary applications. Experimental and theoretical studies of oxygen reduction (OR) in novel acid and alkaline electrolytes on smooth and supported Pt have been carried out. Similar kinetically limited rates for OR were measured in the super-acid electrolytes trifluoromethane sulfonic acid (TFMSA) and tetrafluoroethane-1,2-disulfonic acid (TFEDSA), with the rotating disk electrode (RDE) technique at 23 C and pH = 1. The mechanism for OR on Pt in alkaline electrolytes is complicated by the concurrent oxidation and reduction of Pt. Rotating ring-disk electrode (RRDE) studies carried out with anodic and cathodic potential sweeps in 0.1 to 6.9 M KOH and 0.1 to 4.0 M K{sub 2}CO{sub 3} revealed similar currents when corrected for O{sub 2} solubility differences. Porous gas diffusion electrodes (GDE) with supported Pt catalyst were studied in a special cell with low uncompensated solution resistance. Cyclic voltammograms yielded measurements of the wetted areas of carbon and Pt and the local electrolyte composition. Models for the steady-state operation of porous GDE's were developed. These models account for the diffusion and reaction of O{sub 2} and ionic transport in KOH and K{sub 2}CO{sub 3}. The results suggest that modifications of the GDE structure will be necessary to obtain good performance with aqueous carbonate electrolytes.

  5. Molecular dynamics simulation of electrokinetic flow of an aqueous electrolyte solution in nanochannels

    NASA Astrophysics Data System (ADS)

    Yoshida, Hiroaki; Mizuno, Hideyuki; Kinjo, Tomoyuki; Washizu, Hitoshi; Barrat, Jean-Louis

    2014-06-01

    Electrokinetic flows of an aqueous NaCl solution in nanochannels with negatively charged surfaces are studied using molecular dynamics simulations. The four transport coefficients that characterize the response to weak electric and pressure fields, namely, the coefficients for the electrical current in response to the electric field (Mjj) and the pressure field (Mjm), and those for the mass flow in response to the same fields (Mmj and Mmm), are obtained in the linear regime using a Green-Kubo approach. Nonequilibrium simulations with explicit external fields are also carried out, and the current and mass flows are directly obtained. The two methods exhibit good agreement even for large external field strengths, and Onsager's reciprocal relation (Mjm = Mmj) is numerically confirmed in both approaches. The influence of the surface charge density on the flow is also considered. The values of the transport coefficients are found to be smaller for larger surface charge density, because the counter-ions strongly bound near the channel surface interfere with the charge and mass flows. A reversal of the streaming current and of the reciprocal electro-osmotic flow, with a change of sign of Mmj due to the excess co-ions, takes places for very high surface charge density.

  6. Conductance of electrolytes in 1-propanol solutions from -40 to 25 degrees C

    SciTech Connect

    Barthel, J.; Hilbinger, H.; Schmeer, G.; Wachter, R.

    1986-07-01

    Conductance data for solutions of LiCl, NaBr, Nal, Kl, KSCN, Rbl, Et/sub 4/NI, Pr/sub 4/NI, Bu/sub 4/NI, Bu/sub 4/NClO/sub 4/, n-Am/sub 4/NI, n-Hept/sub 4/NI, Me/sub 2/Bu/sub 2/NI, MeBu/sub 3/NI, EtBu/sub 3/NI, i-Am/sub 3/BuNI, and i-Am/sub 3/BuNBPh/sub 4/ in 1-propanol at -40, -30, -20, -10, 0, 10, and 25 degrees C are communicated and discussed. Evaluation of the data is performed on the basis of a conductance equation that includes a term in c /SUP 3/2/ . Single ion conductances at 25 and 10 degrees C are determined with the help of transference numbers t/sub 0//sup +/ (KSCN/PrOH); the data are compared to data estimated by other methods. Ion-pair association constants and their temperature dependence are discussed in terms of contact and solvent separated ion pairs, and the role of non-coulombic forces is shown with the help of an appropriate splitting of the Gibbs energy of ion-pair formation.

  7. Molecular dynamics simulation of electrokinetic flow of an aqueous electrolyte solution in nanochannels.

    PubMed

    Yoshida, Hiroaki; Mizuno, Hideyuki; Kinjo, Tomoyuki; Washizu, Hitoshi; Barrat, Jean-Louis

    2014-06-01

    Electrokinetic flows of an aqueous NaCl solution in nanochannels with negatively charged surfaces are studied using molecular dynamics simulations. The four transport coefficients that characterize the response to weak electric and pressure fields, namely, the coefficients for the electrical current in response to the electric field (M(jj)) and the pressure field (M(jm)), and those for the mass flow in response to the same fields (M(mj) and M(mm)), are obtained in the linear regime using a Green-Kubo approach. Nonequilibrium simulations with explicit external fields are also carried out, and the current and mass flows are directly obtained. The two methods exhibit good agreement even for large external field strengths, and Onsager's reciprocal relation (M(jm) = M(mj)) is numerically confirmed in both approaches. The influence of the surface charge density on the flow is also considered. The values of the transport coefficients are found to be smaller for larger surface charge density, because the counter-ions strongly bound near the channel surface interfere with the charge and mass flows. A reversal of the streaming current and of the reciprocal electro-osmotic flow, with a change of sign of M(mj) due to the excess co-ions, takes places for very high surface charge density. PMID:24908029

  8. Interactions of lysozyme in concentrated electrolyte solutions from dynamic light-scattering measurements.

    PubMed Central

    Kuehner, D E; Heyer, C; Rämsch, C; Fornefeld, U M; Blanch, H W; Prausnitz, J M

    1997-01-01

    The diffusion of hen egg-white lysozyme has been studied by dynamic light scattering in aqueous solutions of ammonium sulfate as a function of protein concentration to 30 g/liter. Experiments were conducted under the following conditions: pH 4-7 and ionic strength 0.05-5.0 M. Diffusivity data for ionic strengths up to 0.5 M were interpreted in the context of a two-body interaction model for monomers. From this analysis, two potential-of-mean-force parameters, the effective monomer charge, and the Hamaker constant were obtained. At higher ionic strength, the data were analyzed using a model that describes the diffusion coefficient of a polydisperse system of interacting protein aggregates in terms of an isodesmic, indefinite aggregation equilibrium constant. Data analysis incorporated multicomponent virial and hydrodynamic effects. The resulting equilibrium constants indicate that lysozyme does not aggregate significantly as ionic strength increases, even at salt concentrations near the point of salting-out precipitation. PMID:9414232

  9. Hydrolysis kinetics of lead silicate glass in acid solution

    NASA Astrophysics Data System (ADS)

    Rahimi, Rafi Ali; Sadrnezhaad, Sayed Khatibuleslam; Raisali, Gholamreza; Hamidi, Amir

    2009-06-01

    Hydrolysis kinetics of the lead silicate glass (LSG) with 40 mol% PbO in 0.5 N HNO 3 aqueous acid solution was investigated. The surface morphology and the gel layer thickness were studied by scanning electron microscopy (SEM) micrographs. Energy dispersive X-ray spectroscopy (EDS) and inductively coupled plasma spectroscopy (ICP) were used to determine the composition of the gel layer and the aqueous solution, respectively. The silicon content of the dissolution products was determined by using weight-loss data and compositions of the gel layer and the solution. The kinetic parameters were determined using the shrinking-core-model (SCM) for rate controlling step. The activation energy obtained for hydrolysis reaction was Qche = 56.07 kJ/mole. The diffusion coefficient of the Pb ions from the gel layer was determined by using its concentration in solution and in LSG. The shrinkage of the sample and the gel layer thickness during dissolution process were determined.

  10. Electrokinetics of the silica and aqueous electrolyte solution interface: Viscoelectric effects.

    PubMed

    Hsu, Wei-Lun; Daiguji, Hirofumi; Dunstan, David E; Davidson, Malcolm R; Harvie, Dalton J E

    2016-08-01

    electrokinetic experiments to measure surface charge characteristics within this experimentally relevant high pH and moderate to high salt concentration range. At low salt concentrations (<5×10(-3)M) we find that there is a lack of consistency in previously measured channel conductivities conducted under similar solution conditions (pH, salt concentration), preventing a conclusive assessment of any model suitability in this regime. PMID:27217082

  11. Solution Preserves Nucleic Acids in Body-Fluid Specimens

    NASA Technical Reports Server (NTRS)

    Pierson, Duane L.; Stowe, Raymond P.

    2004-01-01

    A solution has been formulated to preserve deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) in specimens of blood, saliva, and other bodily fluids. Specimens of this type are collected for diagnostic molecular pathology, which is becoming the method of choice for diagnosis of many diseases. The solution makes it possible to store such specimens at room temperature, without risk of decomposition, for subsequent analysis in a laboratory that could be remote from the sampling location. Thus, the solution could be a means to bring the benefits of diagnostic molecular pathology to geographic regions where refrigeration equipment and diagnostic laboratories are not available. The table lists the ingredients of the solution. The functions of the ingredients are the following: EDTA chelates divalent cations that are necessary cofactors for nuclease activity. In so doing, it functionally removes these cations and thereby retards the action of nucleases. EDTA also stabilizes the DNA helix. Tris serves as a buffering agent, which is needed because minor contaminants in an unbuffered solution can exert pronounced effects on pH and thereby cause spontaneous degradation of DNA. SDS is an ionic detergent that inhibits ribonuclease activity. SDS has been used in some lysis buffers and as a storage buffer for RNA after purification. The use of the solution is straightforward. For example, a sample of saliva is collected by placing a cotton roll around in the subject's mouth until it becomes saturated, then the cotton is placed in a collection tube. Next, 1.5 mL of the solution are injected directly into the cotton and the tube is capped for storage at room temperature. The effectiveness of the solution has been demonstrated in tests on specimens of saliva containing herpes simplex virus. In the tests, the viral DNA, as amplified by polymerase chain reaction, was detected even after storage for 120 days.

  12. Multiphase chemistry of ozone on fulvic acids solutions.

    PubMed

    Brigante, Marcello; D'Anna, Barbara; Conchon, Pierre; George, Christian

    2008-12-15

    By means of a wetted-wall flow tube, we studied the multiphase chemistry of ozone on aqueous solutions containing fulvic acids (FA), taken as proxies for atmospheric "humic like substances", so-called HULIS. In these experiments, the loss of gaseous O3 was monitored by UV-visible absorption spectroscopy at the reactor outlet (i.e., after contact between the gaseous and liquid phases). Measurements are reported in terms of dimensionless uptake coefficients (gamma) in the range from 1.6 x 10(-7) to 1.3 x 10(-5) depending on ozone gas phase concentration (in the range from 6.6 to 34.4 x 10(11) molecules cm(-3)) and fulvic acid aqueous concentration (in the range from 0.25 to 2.5 mg L(-1)) and pH (in the range from 2.5 to 9.2). The measured kinetics were observed to follow a Langmuir-Hinshelwood type mechanism, in which O3 first adsorbs on the liquid surface and then reacts with the Fulvic Acid molecules. The reported uptake coefficients are greatly increased over those measured on pure water, demonstrating that the presence in solution of fulvic acids does greatly enhance the uptake kinetics. Accordingly, the chemical interactions of fulvic acids (or HULIS) may be a driving force for the uptake of ozone on liquid organic aerosols and can also represent an important mechanism for the O3 deposition to the rivers and lakes. PMID:19174887

  13. Acid hydrolysis of cellulose in zinc chloride solution

    SciTech Connect

    Cao, N.J.; Xu, Q.; Chen, L.F.

    1995-12-31

    The efficient conversion of cellulosic materials to ethanol has been hindered by the low yield of sugars, the high energy consumption in pretreatment processes, and the difficulty of recycling the pre-treatment agents. Zinc chloride may provide an alternative for pre-treating biomass prior to the hydrolysis of cellulose. The formation of a zinc-cellulose complex during the pretreatment of cellulose improves the yield of glucose in both the enzymatic and acid hydrolysis of cellulose. Low-temperature acid hydrolysis of cellulose in zinc chloride solution is carried out in two stages, a liquefaction stage and a saccharification stage. Because of the formation of zinc-cellulose complex in the first stage, the required amount of acid in the second stage has been decreased significantly. In 67% zinc chloride solution, a 99.5% yield of soluble sugars has been obtained at 70{degrees}C and 0.5M acid concentration. The ratio of zinc chloride to cellulose has been reduced from 4.5 to 1.5, and the yield of soluble sugars is kept above 80%. The rate of hydrolysis is affected by the ratio of zinc chloride to cellulose, acid concentration, and temperature.

  14. Micro-electro-mechanical systems phosphoric acid fuel cell

    DOEpatents

    Sopchak, David A.; Morse, Jeffrey D.; Upadhye, Ravindra S.; Kotovsky, Jack; Graff, Robert T.

    2010-08-17

    A phosphoric acid fuel cell system comprising a porous electrolyte support, a phosphoric acid electrolyte in the porous electrolyte support, a cathode electrode contacting the phosphoric acid electrolyte, and an anode electrode contacting the phosphoric acid electrolyte.

  15. Micro-electro-mechanical systems phosphoric acid fuel cell

    DOEpatents

    Sopchak, David A.; Morse, Jeffrey D.; Upadhye, Ravindra S.; Kotovsky, Jack; Graff, Robert T.

    2010-12-21

    A phosphoric acid fuel cell system comprising a porous electrolyte support, a phosphoric acid electrolyte in the porous electrolyte support, a cathode electrode contacting the phosphoric acid electrolyte, and an anode electrode contacting the phosphoric acid electrolyte.

  16. Solution influence on biomolecular equilibria - Nucleic acid base associations

    NASA Technical Reports Server (NTRS)

    Pohorille, A.; Pratt, L. R.; Burt, S. K.; Macelroy, R. D.

    1984-01-01

    Various attempts to construct an understanding of the influence of solution environment on biomolecular equilibria at the molecular level using computer simulation are discussed. First, the application of the formal statistical thermodynamic program for investigating biomolecular equilibria in solution is presented, addressing modeling and conceptual simplications such as perturbative methods, long-range interaction approximations, surface thermodynamics, and hydration shell. Then, Monte Carlo calculations on the associations of nucleic acid bases in both polar and nonpolar solvents such as water and carbon tetrachloride are carried out. The solvent contribution to the enthalpy of base association is positive (destabilizing) in both polar and nonpolar solvents while negative enthalpies for stacked complexes are obtained only when the solute-solute in vacuo energy is added to the total energy. The release upon association of solvent molecules from the first hydration layer around a solute to the bulk is accompanied by an increase in solute-solvent energy and decrease in solvent-solvent energy. The techniques presented are expectd to displace less molecular and more heuristic modeling of biomolecular equilibria in solution.

  17. Electrodialysis synthesis of concentrated solutions of perrhenic acid

    NASA Astrophysics Data System (ADS)

    Palant, A. A.; Bryukvin, V. A.; Levin, A. M.; Reshetova, O. V.

    2011-03-01

    The presented results demonstrate the possibility of electrodialysis production of concentrated solutions of perrhenic acid (HReO4 concentration >400 g/l). KReO4 is used as a precursor. The investigations are performed in a three-chamber electrodialysis cell in a continuous mode. The optimal processing parameters are as follows: the current is 3-5 A, the voltage is 30-40 V, and the anode chamber temperature is 20-25°C. Grade AR-0 ammonium perrhenate is precipitated from the obtained HReO4 solution.

  18. Method for extracting lanthanides and actinides from acid solutions

    DOEpatents

    Horwitz, E. Philip; Kalina, Dale G.; Kaplan, Louis; Mason, George W.

    1985-01-01

    A process for the recovery of actinide and lanthanide values from aqueous acidic solutions with an organic extractant having the formula: ##STR1## where .phi. is phenyl, R.sup.1 is a straight or branched alkyl or alkoxyalkyl containing from 6 to 12 carbon atoms and R.sup.2 is an alkyl containing from 3 to 6 carbon atoms. The process is suitable for the separation of actinide and lanthanide values from fission product values found together in high level nuclear reprocessing waste solutions.

  19. Studies on the adsorption of americium on alumina from aqueous nitric acid-oxalic acid solutions

    SciTech Connect

    Subba Rao, M.; Gaikwad, A.M.; Rao, V.K.; Natarajan, P.R.

    1985-01-01

    This paper reports a study on the adsorption of Am(III) on alumina from oxalic acid-nitric acid solutions. Distribution coefficients for Am(III) on alumina at different oxalic acid-nitric acid concentrations have been determined and optimum conditions for loading and elution of Am from alumina columns have been established. Separation of Am from Pu and the effects of other ions, such as U(VI) and Fe(III), have also been studied. Am and Pu recoveries better than 99.5% were obtained. 3 references, 2 figures, 5 tables.

  20. DC diaphragm discharge in water solutions of selected organic acids

    NASA Astrophysics Data System (ADS)

    Vyhnankova, Edita J.; Hammer, Malte U.; Reuter, Stephan; Krcma, Frantisek

    2015-07-01

    Effect of four simple organic acids water solution on a DC diaphragm discharge was studied. Efficiency of the discharge was quantified by the hydrogen peroxide production determined by UV-VIS spectrometry of a H2O2 complex formed with specific titanium reagent. Automatic titration was used to study the pH behaviour after the plasma treatment. Optical emission spectroscopy overview spectra were recorded and detailed spectra of OH band and Hβ line were used to calculate the rotational temperature and comparison of the line profile (reflecting electron concentration) in the acid solutions. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  1. Interaction of Ethyl Alcohol Vapor with Sulfuric Acid Solutions

    NASA Technical Reports Server (NTRS)

    Leu, Ming-Taun

    2006-01-01

    We investigated the uptake of ethyl alcohol (ethanol) vapor by sulfuric acid solutions over the range approx.40 to approx.80 wt % H2SO4 and temperatures of 193-273 K. Laboratory studies used a fast flow-tube reactor coupled to an electron-impact ionization mass spectrometer for detection of ethanol and reaction products. The uptake coefficients ((gamma)) were measured and found to vary from 0.019 to 0.072, depending upon the acid composition and temperature. At concentrations greater than approx.70 wt % and in dilute solutions colder than 220 K, the values approached approx.0.07. We also determined the effective solubility constant of ethanol in approx.40 wt % H2SO4 in the temperature range 203-223 K. The potential implications to the budget of ethanol in the global troposphere are briefly discussed.

  2. Study of a Li-air battery having an electrolyte solution formed by a mixture of an ether-based aprotic solvent and an ionic liquid

    NASA Astrophysics Data System (ADS)

    Cecchetto, Laura; Salomon, Mark; Scrosati, Bruno; Croce, Fausto

    2012-09-01

    Recent studies have clearly demonstrated that cyclic and linear carbonates are unstable when used in rechargeable Li-air batteries employing aprotic solvents mostly due to the cathodic formation of superoxide during the oxygen reduction reaction. In particular, it has been ascertained that nucleophilic attack by superoxide anion radical, O2-rad , at O-alkyl carbon is a common mechanism of decomposition of organic carbonates. Moreover, theoretical calculations showed that ether chemical functionalities are stable against nucleophilic substitution induced by superoxide. Aim of this study is to report on a new electrolyte solution for Li-air battery formed by a mixture of an ether-based aprotic solvent with an ionic liquid (IL). The IL-based electrolyte was obtained by mixing the pure ionic liquid N-methyl-(n-butyl) pyrrolidinium bis(trifluoromethane sulfonyl) imide (here denoted as PYR14TFSI) to a 0.91 M solution of lithium triflate (LiCF3SO3) in tetra ethylene glycol dimethyl etcher (TEGDME). We observed that the presence of IL beneficially affects the kinetics and the reversibility of the oxygen reactions involved at the cathode. The most significant result being a lower overvoltage for the charge reaction, compared to a Li/air cell containing the same electrolyte solution without IL.

  3. Proton conductive inorganic-organic hybrid membranes functionalized with phosphonic acid for polymer electrolyte fuel cell

    NASA Astrophysics Data System (ADS)

    Umeda, Junji; Suzuki, Masashi; Kato, Masaki; Moriya, Makoto; Sakamoto, Wataru; Yogo, Toshinobu

    Proton conductive sol-gel derived hybrid membranes were synthesized from aromatic derivatives of methoxysilanes and ethyl 2-[3-(dihydroxyphosphoryl)-2-oxapropyl]acrylate (EPA). Two aromatic derivatives of methoxysilanes with different number of methoxy groups were used as the starting materials. Hybrid membranes from difunctional (methyldimethoxysilylmethyl)styrene (MDMSMS(D))/EPA revealed a higher chemical stability and mechanical properties than those from monofunctional (dimethylmethoxysilylmethyl)styrene (DMMSMS(M))/EPA. The membrane-electrode assembly (MEA) using the hybrid membranes as electrolytes worked as a fuel cell at 100 °C under saturated humidity. The DMMSMS(M)/EPA membrane-based MEA showed a larger current density than that from MDMSMS(D)/EPA. On the other hand, the MDMSMS(D)/EPA membrane-based MEA exhibited higher open circuit voltages than the DMMSMS(M)/EPA-based MEA, and was stable during fuel cell operation at 80 °C at least for 48 h.

  4. Solubility of chlorine in aqueous hydrochloric acid solutions.

    PubMed

    Alkan, Mahir; Oktay, Münir; Kocakerim, M Muhtar; Copur, Mehmet

    2005-03-17

    The solubility of chlorine in aqueous hydrochloric acid solutions was studied. The effects of HCl concentration and temperature on the solubility were evaluated, and the thermodynamic parameters of the dissolution were calculated. It was found that the solubility isotherms had a minimum at about 0.5M HCl concentration at all the temperatures studied and that solubility decreased with the increase of temperature at all the HCl concentration range investigated. PMID:15752843

  5. Recovery of rhenium from sulfuric acid solutions with activated coals

    SciTech Connect

    Troshkina, I.D.; Naing, K.Z.; Ushanova, O.N.; P'o, V.; Abdusalomov, A.A.

    2006-09-15

    Equilibrium and kinetic characteristics of rhenium sorption from sulfuric acid solutions (pH 2) by activated coals produced from coal raw materials (China) were studied. Constants of the Henry equation describing isotherms of rhenium sorption by activated coals were calculated. The effective diffusion coefficients of rhenium in the coals were determined. The dynamic characteristics of rhenium sorption and desorption were determined for the activated coal with the best capacity and kinetic characteristics.

  6. Acid mine drainage: An economic total resource recovery solution

    SciTech Connect

    Clarke, R.L.; Clarke, S.R.; Brackenbury, D.R.

    1995-12-31

    A common feature of abandoned hard rock mines and subterranean coal mines is the creation of toxic and acidic solution often containing iron, copper, zinc, lead, cadmium, manganese and alkaline earth and alkali metals. A process is described which sequentially removes heavy metals using electrochemical ion exchange and rotating cylinder electrodes. Studies summarized indicate recovery of copper, zinc, iron, and aluminum oxide; selective stripping of arsenic, cadmium, chromium, and lead; and recovery of water acceptable for drinking after removal of heavy metals.

  7. Volumetric Titrations Using Electrolytically Generated Reagents for the Determination of Ascorbic Acid and Iron in Dietary Supplement Tablets: An Undergraduate Laboratory Experiment

    ERIC Educational Resources Information Center

    Scanlon, Christopher; Gebeyehu, Zewdu; Griffin, Kameron; Dabke, Rajeev B.

    2014-01-01

    An undergraduate laboratory experiment for the volumetric quantitative analysis of ascorbic acid and iron in dietary supplement tablets is presented. Powdered samples of the dietary supplement tablets were volumetrically titrated against electrolytically generated reagents, and the mass of dietary reagent in the tablet was determined from the…

  8. Gelled electrolytes for use in absorptive glass mat valve-regulated lead-acid (AGM VRLA) batteries working under 100% depth of discharge conditions

    NASA Astrophysics Data System (ADS)

    Tantichanakul, Titiporn; Chailapakul, Orawon; Tantavichet, Nisit

    2011-10-01

    Gelled electrolytes prepared from fumed silica for use in absorptive glass mat valve-regulated lead-acid (AGM VRLA) batteries and the effect of veratraldehyde addition on the electrochemical behavior and performance of AGM VRLA batteries are investigated. Cyclic voltammetry is used to investigate differences in the electrochemical behaviors of nongelled and gelled electrolytes and between gelled electrolytes with and without veratraldehyde. Battery performance is tested under 100% depth of discharge (100% DoD) conditions at both low- (0.1 C) and high- (1 C) rate discharges. The addition of silica or veratraldehyde does not affect the main reaction of the lead-acid batteries but tends to suppress the hydrogen evolution reaction. AGM VRLA batteries with gelled electrolytes have a higher discharge capacity and longer cycle life than the conventional nongel AGM VRLA batteries. The addition of 0.005% (w/v) veratraldehyde further improves battery performance, but higher (0.01%, w/v) veratraldehyde concentrations reduce it and correlate with the enhanced growth of lead sulfate crystals. The AGM VRLA battery prepared from a gelled electrolyte containing 0.005% (w/v) veratraldehyde provides the best battery performance in every operating temperature studied (0-60 °C).

  9. Surface tensions of solutions containing dicarboxylic acid mixtures

    NASA Astrophysics Data System (ADS)

    Lee, Jae Young; Hildemann, Lynn M.

    2014-06-01

    Organic solutes tend to lower the surface tension of cloud condensation nuclei, allowing them to more readily activate. The surface tension of various dicarboxylic acid aerosol mixtures was measured at 20 °C using the Wilhelmy plate method. At lower concentrations, the surface tension of a solution with equi-molar mixtures of dicarboxylic acids closely followed that of a solution with the most surface-active organic component alone. Measurements of surface tension for these mixtures were lower than predictions using Henning's model and the modified Szyszkowski equation, by ˜1-2%. The calculated maximum surface excess (Γmax) and inverse Langmuir adsorption coefficient (β) from the modified Szyszkowski equation were both larger than measured values for 6 of the 7 mixtures tested. Accounting for the reduction in surface tension in the Köhler equation reduced the critical saturation ratio for these multi-component mixtures - changes were negligible for dry diameters of 0.1 and 0.5 μm, but a reduction from 1.0068 to 1.0063 was seen for the 4-dicarboxylic acid mixture with a dry diameter of 0.05 μm.

  10. Dehydration and oxidation of cellulose hydrolysis products in acidic solution

    SciTech Connect

    Garves, K.

    1981-01-01

    The dehydration of cotton cellulose in aqueous solutions in the presence of Ac/sub 2/O, AcOH, HCl, H/sub 2/SO/sub 4/ or HBr proceeded by hydrolysis to carbohydrates with acetate groups, followed by conversion to 5-(hydroxymethyl)furfural (I) and then, to levulinic acid (II) accompanied by humic acids. For the formation of I, HCl was a more efficient and selective catalyst than H/sub 2/SO/sub 4/, and the formation of II was promoted by high acid and H/sub 2/O concentrations in the medium. The addition of FeCl/sub 3/ to the dehydration mixture with HCl and continuous distillation led to the isolation of furfural.

  11. The Application of Electrodialysis to Desalting an Amino Acid Solution

    NASA Astrophysics Data System (ADS)

    García-García, Vicente; Montiel, Vicente; González-García, José; Expósito, Eduardo; Iniesta, Jesús; Bonete, Pedro; Inglés, Marina

    2000-11-01

    One of the main difficulties in preparing pharmaceutical products is isolating them from aqueous solutions of high salt concentration, as a high purity must be obtained. Several methods that employ organic solvents are normally used. In this paper, a novel method, electrodialysis, is presented together with its application to the desalting of an industrial effluent comprising an amino acid (p-hydroxyphenylglycine) with a high salt content (ammonium sulfate and sodium dihydrogenphosphate). It was possible to remove more than 70% of the initial salt content. From this solution with a low salt content, it is possible to isolate the amino acid with a higher purity. This experiment will enable the student to gain a useful knowledge of this technique and to work with typical figures of merit of electrodialysis such as current efficiency, electrical energy consumption, production of the process, removal of salt, and loss of amino acid. In addition the student learns the use of chromatographic techniques applied to the analysis of amino acids (HPLC) and salts (IC).

  12. Methanol Uptake By Low Temperature Aqueous Sulfuric Acid Solutions

    NASA Technical Reports Server (NTRS)

    Iraci, Laura T.; Essin, Andrew M.; Golden, David M.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    To evaluate the role of upper tropospheric and lower stratospheric aerosols in the global budget of methanol, the solubility and reactivity of CH3OH in aqueous sulfuric acid solutions are under investigation. Using standard uptake techniques in a Knudsen cell reactor, we have measured the effective Henry's law coefficient, H(*), for methanol dissolution into 45 to 70 percent by weight H2SO4. We find that methanol solubility ranges from 10(exp 5) to 10(exp 8) M/atm and increases with decreasing temperature and with increasing sulfuric acid content. These solubility measurements include uptake due to physical solvation and all rapid equilibria which are established in solution. Our data indicate that simple uptake by aqueous sulfuric acid particles will not be a significant sink for methanol in the UT/LS. These results differ from those recently reported in the literature, and an explanation of this disparity will be presented. In addition to solvation, reaction between primary alcohols and sulfuric acid does occur, leading to the production of alkyl sulfates. Literature values for the rate of this reaction suggest that formation of CH3OSO3H may proceed in the atmosphere but is not significant under our experimental conditions. Results obtained using a complementary equilibrium measurement technique confirm this directly. In addition, the extent of methanol sequestration via formation of mono- and dimethylsulfate will be evaluated under several atmospheric conditions.

  13. Experimental equilibrium between acid gases and ethanolamine solutions

    SciTech Connect

    Bhairi, A.M.

    1984-01-01

    The general subject area of this study is equilibrium solubility of carbon dioxide and hydrogen sulfide in solutions of some common ethanolamines. The amines studied are most widely used in the area of gas sweetening. They include monoethanolamine, diglycolamine, diethanolamine and methyldiethanolamine. Only limited data are available for some of these amines. The process involved developing simple apparatus and procedure for investigating the equilibrium solubility of carbon dioxide and hydrogen sulfide in aqueous alkanolamine solutions. The procedure uses a single equilibrium cell. No gas chromatograph nor liquid chemical analysis is required. Measurements of the solubility were made in different amine solution concentrations at acid gas partial pressures to 1000 psia and temperatures from 77 to 240{degree}F. The method used was found to be sound as indicated by the consistency and reproducibility of the data.

  14. Porous aluminum room temperature anodizing process in a fluorinated-oxalic acid solution

    NASA Astrophysics Data System (ADS)

    Dhahri, S.; Fazio, E.; Barreca, F.; Neri, F.; Ezzaouia, H.

    2016-08-01

    Anodizing of aluminum is used for producing porous insulating films suitable for different applications in electronics and microelectronics. Porous-type aluminum films are most simply realized by galvanostatic anodizing in aqueous acidic solutions. The improvement in application of anodizing technique is associated with a substantial reduction of the anodizing voltage at appropriate current densities as well as to the possibility to carry out the synthesis process at room temperature in order to obtain a self-planarizing dielectric material incorporated in array of super-narrow metal lines. In this work, the anodizing of aluminum to obtain porous oxide was carried out, at room temperature, on three different substrates (glass, stainless steel and aluminum), using an oxalic acid-based electrolyte with the addition of a relatively low amount of 0.4 % of HF. Different surface morphologies, from nearly spherical to larger porous nanostructures with smooth edges, were observed by means of scanning electron microscopy. These evidences are explained by considering the formation, transport and adsorption of the fluorine species which react with the Al3+ ions. The behavior is also influenced by the nature of the original substrate.

  15. Comparison of the oxygen reduction reaction between NaOH and KOH solutions on a Pt electrode: the electrolyte-dependent effect.

    PubMed

    Jin, Wei; Du, Hao; Zheng, Shili; Xu, Hongbin; Zhang, Yi

    2010-05-20

    The oxygen reduction reaction (ORR) on a polycrystalline Pt surface was studied using cyclic voltammetry techniques, and the influence of reaction media on the ORR is examined by comparing the ORR in NaOH and KOH solutions with concentration ranging from 0.5 to 14 M at 298 K. The results show that, in NaOH and KOH solutions, the ORR, a quasi-reversible diffusion-controlled reaction, is largely dependent on the electrolyte conditions, and KOH solutions are superior to NaOH solutions for the ORR process in both thermodynamic and kinetic consideration. As the alkaline concentration increases, the ORR performance frustrates, and the protonation of superoxide is suppressed; thus, the ORR shifts from a 2e reduction pathway to a 1e reduction pathway in both solutions. PMID:20411967

  16. Effect of hydrochloric acid on sound absorption and relaxation frequency in magnesium sulfate solutions

    NASA Astrophysics Data System (ADS)

    Fisher, F. H.

    2002-05-01

    The epic work of Kurtze and Tamm on sound absorption spectroscopy in divalent sulfate electrolyte solutions (1953) from the low-kHz region up to over 200 MHz revealed astonishing variability at frequencies below 10 MHz and a common relaxation frequency at about 200 MHz. For magnesium sulfate [Epsom salts] solutions, the salt producing 30× the absorption of fresh water below the 100-kHz region in the oceans at low concentrations [~0.02 moles/liter], Kurtze and Tamm investigated the effects of adding HC1 or H2SO4. They found that as formal pH increased, the results were different for these acids in reducing the sound absorption. Fisher (1983) found that if the absorption was plotted against free hydrogen, ion concentration was the same. We used the 100-liter titanium sphere, a spare ballast tank from the WHOI submarine ALVIN. With precise temperature control, we found an increase in the relaxation frequency as HC1 was added in conjunction with the reduction in sound absorption. The results will be presented and an explanation will be proposed in the context of the Eigen and Tamm multistate dissociation model for MgSO4 (1962) which explains the effects of pressure on both absorption and conductance. [Work supported by ONR.] The author acknowledges C. C. Hsu for his work on this project.

  17. Effect of phytic acid, ethylenediaminetetraacetic acid, and chitosan solutions on microhardness of the human radicular dentin

    PubMed Central

    Nikhil, Vineeta; Jaiswal, Shikha; Bansal, Parul; Arora, Rohit; Raj, Shalya; Malhotra, Pulkit

    2016-01-01

    Aim: The purpose of this study was to evaluate the effect of phytic acid, ethylenediaminetetraacetic acid (EDTA), and chitosan solutions on the microhardness of human radicular dentin. Materials and Methods: Thirty dentin specimens were randomly divided into three groups of 10 specimens each according to the irrigant used: G1 — 1% phytic acid, G2 — 17% EDTA, and G3 — 0.2% chitosan. A standardized volume of each chelating solution was used for 3 min. Dentin microhardness was measured before and after application at the cervical, middle, and apical levels with a Vickers indenter under a 200-g load and a 10-s dwell time. The results were analyzed using one-way analysis of variance (ANOVA) and Student's t test. Results: Microhardness of the radicular dentin varied at the cervical, middle, and apical levels. EDTA had the greatest overall effect, causing a sharp percentage reduction in dentin microhardness with a significant difference from phytic acid and chitosan (P = 0.002). However, phytic acid and chitosan differed insignificantly from each other (P = 0.887). Conclusion: All tested chelating solutions reduced microhardness of the radicular dentin layer at all the levels. However, reduction was least at the apical level. EDTA caused more reduction in dentin microhardness than chitosan while phytic acid reduced the least. PMID:27099428

  18. Pyrophosphate complexation of tin(II) in aqueous solutions as applied in electrolytes for the deposition of tin and tin alloys such as white bronze.

    PubMed

    Buchner, Magnus R; Kraus, Florian; Schmidbaur, Hubert

    2012-08-20

    Electrodeposition of tin and tin alloys from electrolytes containing tin(II) and pyrophosphates is an important process in metal finishing, but the nature of the tin pyrophosphate complexes present in these solutions in various pH regions has remained unknown. Through solubility and pH studies, IR and (31)P and (119)Sn NMR spectroscopic investigations of solutions obtained by dissolving Sn(2)P(2)O(7) in equimolar quantities of either Na(4)P(2)O(7)·10H(2)O or K(4)P(2)O(7) the formation of anionic 1:1 complexes {[Sn(P(2)O(7))]}(n)(2n-) has now been verified and the molecular structures of the monomer (n = 1) and the dimer (n = 2) have been calculated by density functional theory (DFT) methods. Whereas the alkali pyrophosphates Na/K(4)P(2)O(7) give strongly alkaline aqueous solutions (pH ∼13), because of partial protonation of the [P(2)O(7)](4-) anion, the [Sn(P(2)O(7))](2-) anion is not protonated and the solutions of Na/K(2)[Sn(P(2)O(7))] are almost neutral (pH ∼8). The monomeric dianion appears to have a ground state with C(2v) symmetry with the Sn atom in a square pyramidal coordination and the lone pair of electrons in the apical position, while the dimer approaches C(2) symmetry with the Sn atoms in a rhombic pyramidal coordination, also with a sterically active lone pair. A comparison of experimental and calculated IR details favors the monomer as the most abundant species in solution. With an excess of pyrophosphate, 3:2 and 2:1 complexes (P(2)O(7)):(Sn) are first formed, which, in the presence of more pyrophosphate, undergo rapid ligand exchange on the NMR time scale. The structure of the 2:1 complex [Sn(P(2)O(7))(2)](6-) was calculated to have a pyramidal complexation by two 1,5-chelating pyrophosphate ligands. Neutralization of these alkaline solutions by sulfuric or sulfonic acids (H(2)SO(4), MeSO(3)H), as also practiced in electroplating, appears to afford the tin(II) hydrogen pyrophosphates [Sn(P(2)O(7)H)](-) and [Sn(H(2)P(2)O(7))](0). The molecular

  19. Planetary Resources and Astroecology. Planetary Microcosm Models of Asteroid and Meteorite Interiors: Electrolyte Solutions and Microbial Growth- Implications for Space Populations and Panspermia

    NASA Astrophysics Data System (ADS)

    Mautner, Michael N.

    2002-03-01

    Planetary microcosms were constructed using extracts from meteorites that simulate solutions in the pores of carbonaceous chondrites. The microcosms were found to support the growth of complex algal and microbial populations. Such astroecology experiments demonstrate how a diverse ecosystem could exist in fluids within asteroids, and in meteorites that land on aqueous planets. The microcosm solutions were obtained by extracting nutrient electrolytes under natural conditions from powders of the Allende (CV3) and Murchison (CM2) meteorites at low (0.02 g/ml) and high (10.0 g/ml) solid/solution ratios. The latter solutions contain >3 mol/L electrolytes and about 10 g/L organics, that simulate natural fluids in asteroids during aqueous alteration and in the pores of meteorites, which can help prebiotic synthesis and the survival of early microorganisms. These solutions and wet solids were in fact found to support complex self-sustaining microbial communities with populations of 4 × 105 algae and 6 × 106 bacteria and fungi for long periods (>8 months). The results show that planetary microcosms based on meteorites can: assay the fertilities of planetary materials; identify space bioresources; target astrobiology exploration; and model past and future space-based ecosystems. The results show that bioresources in the carbonaceous asteroids can sustain a biomass of 1018 kg, comprising 1032 microorganisms and a human population of 1014. The results also suggest that protoplanetary nebulae can support and disperse microorganisms and can be therefore effective environments for natural and directed panspermia.

  20. Cross-linked poly (vinyl alcohol)/sulfosuccinic acid polymer as an electrolyte/electrode material for H2-O2 proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Ebenezer, D.; Deshpande, Abhijit P.; Haridoss, Prathap

    2016-02-01

    Proton exchange membrane fuel cell (PEMFC) performance with a cross-linked poly (vinyl alcohol)/sulfosuccinic acid (PVA/SSA) polymer is compared with Nafion® N-115 polymer. In this study, PVA/SSA (≈5 wt. % SSA) polymer membranes are synthesized by a solution casting technique. These cross-linked PVA/SSA polymers and Nafion are used as electrolytes and ionomers in catalyst layers, to fabricate different membrane electrode assemblies (MEAs) for PEMFCs. Properties of each MEA are evaluated using scanning electron microscopy, contact angle measurements, impedance spectroscopy and hydrogen pumping technique. I-V characteristics of each cell are evaluated in a H2-O2 fuel cell testing fixture under different operating conditions. PVA/SSA ionomer causes only an additional ≈4% loss in the anode performance compared to Nafion ionomer. The maximum power density obtained from PVA/SSA based cells range from 99 to 117.4 mW cm-2 with current density range of 247 to 293.4 mA cm-2. Ionic conductivity of PVA/SSA based cells is more sensitive to state of hydration of MEA, while maximum power density obtained is less sensitive to state of hydration of MEA. Maximum power density of cross-linked PVA/SSA membrane based cell is about 35% that of Nafion® N-115 based cell. From these results, cross-linked PVA/SSA polymer is identified as potential candidate for PEMFCs.

  1. Probing the Degradation Mechanisms in Electrolyte Solutions for Li-ion Batteries by In-Situ Transmission Electron Microscopy

    SciTech Connect

    Abellan Baeza, Patricia; Mehdi, Beata L.; Parent, Lucas R.; Gu, Meng; Park, Chiwoo; Xu, Wu; Zhang, Yaohui; Arslan, Ilke; Zhang, Jiguang; Wang, Chong M.; Evans, James E.; Browning, Nigel D.

    2014-02-21

    One of the goals in the development of new battery technologies is to find new electrolytes with increased electrochemical stability. In-situ (scanning) transmission electron microscopy ((S)TEM) using an electrochemical fluid cell provides the ability to rapidly and directly characterize electrode/electrolyte interfacial reactions under battery relevant electrochemical conditions. Furthermore, as the electron beam itself causes a localized electrochemical reaction when it interacts with the electrolyte, the breakdown products that occur during the first stages of battery operation can potentially be simulated and characterized using a straightforward in-situ liquid stage (without electrochemical biasing capabilities). In this paper, we have studied the breakdown of a range of inorganic/salt complexes that are used in state-of-the-art Li-ion battery systems. The results of the in-situ (S)TEM experiments matches with previous stability tests performed during battery operation and the breakdown products and mechanisms are also consistent with known mechanisms. This analysis indicates that in-situ liquid stage (S)TEM observations can be used to directly test new electrolyte designs and provide structural insights into the origin of the solid electrolyte interphase (SEI) formation mechanism.

  2. A Long-Life Lithium Ion Battery with Enhanced Electrode/Electrolyte Interface by Using an Ionic Liquid Solution.

    PubMed

    Elia, Giuseppe Antonio; Ulissi, Ulderico; Mueller, Franziska; Reiter, Jakub; Tsiouvaras, Nikolaos; Sun, Yang-Kook; Scrosati, Bruno; Passerini, Stefano; Hassoun, Jusef

    2016-05-10

    In this paper, we report an advanced long-life lithium ion battery, employing a Pyr14 TFSI-LiTFSI non-flammable ionic liquid (IL) electrolyte, a nanostructured tin carbon (Sn-C) nanocomposite anode, and a layered LiNi1/3 Co1/3 Mn1/3 O2 (NMC) cathode. The IL-based electrolyte is characterized in terms of conductivity and viscosity at various temperatures, revealing a Vogel-Tammann-Fulcher (VTF) trend. Lithium half-cells employing the Sn-C anode and NMC cathode in the Pyr14 TFSI-LiTFSI electrolyte are investigated by galvanostatic cycling at various temperatures, demonstrating the full compatibility of the electrolyte with the selected electrode materials. The NMC and Sn-C electrodes are combined into a cathode-limited full cell, which is subjected to prolonged cycling at 40 °C, revealing a very stable capacity of about 140 mAh g(-1) and retention above 99 % over 400 cycles. The electrode/electrolyte interface is further characterized through a combination of electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) investigations upon cell cycling. The remarkable performances reported here definitively indicate that IL-based lithium ion cells are suitable batteries for application in electric vehicles. PMID:26990320

  3. Development and evaluation of a multimedia e-learning resource for electrolyte and acid-base disorders.

    PubMed

    Davids, Mogamat Razeen; Chikte, Usuf M E; Halperin, Mitchell L

    2011-09-01

    This article reports on the development and evaluation of a Web-based application that provides instruction and hands-on practice in managing electrolyte and acid-base disorders. Our teaching approach, which focuses on concepts rather than details, encourages quantitative analysis and a logical problem-solving approach. Identifying any dangers to the patient is a vital first step. Concepts such as an "appropriate response" to a given perturbation and the need for electroneutrality in body fluids are used repeatedly. Our Electrolyte Workshop was developed using Flash and followed an iterative design process. Two case-based tutorials were built in this first phase, with one tutorial including an interactive treatment simulation. Users select from a menu of therapies and see the impact of their choices on the patient. Appropriate text messages are displayed, and changes in body compartment sizes, brain size, and plasma sodium concentrations are illustrated via Flash animation. Challenges encountered included a shortage of skilled Flash developers, budgetary constraints, and challenges in communication between the authors and the developers. The application was evaluated via user testing by residents and specialists in internal medicine. Satisfaction was measured with a questionnaire based on the System Usability Scale. The mean System Usability Scale score was 78.4 ± 13.8, indicating a good level of usability. Participants rated the content as being scientifically sound; they liked the teaching approach and felt that concepts were conveyed clearly. They indicated that the application held their interest, that it increased their understanding of hyponatremia, and that they would recommend this learning resource to others. PMID:21908840

  4. Toluene nitration in irradiated nitric acid and nitrite solution

    SciTech Connect

    Gracy Elias; Bruce J. Mincher; Stephen P. Mezyk; Jim Muller; Leigh R. Martin

    2011-04-01

    The kinetics, mechanisms, and stable products produced for the aryl alkyl mild ortho-para director - toluene, in irradiated nitric acid and neutral nitrite solutions were investigated using ?, and pulse radiolysis. Electron pulse radiolysis was used to determine the bimolecular rate constants for the reaction of toluene with different transient species produced by irradiation. HPLC with UV detection was primarily used to assess the stable reaction products. GC-MS and LC-MS were used to confirm the results from HPLC. Free-radical nitration reaction products were found in irradiated acidic and neutral media. In acidic medium, the ring substitution and side chain substitution and oxidation produced different nitro products. In ring substitution, nitrogen oxide radicals were added mainly to hydroxyl radical-produced cyclohexadienyl radical, and in side chain substitution they were added to the carbon-centered benzyl radical produced by H-atom abstraction. In neutral nitrite toluene solution, radiolytic ring nitration products approached a statistically random distribution, suggesting a free-radical reaction involving addition of the •NO2 radical.

  5. Effect of acid dopants in biodegradable gel polymer electrolyte and the performance in an electrochemical double layer capacitor

    NASA Astrophysics Data System (ADS)

    Sudhakar, Y. N.; Selvakumar, M.; Krishna Bhat, D.

    2015-09-01

    Proton-conducting biodegradable gellan gum gel polymer electrolytes (GPEs) have been prepared using three different dopants, namely ortho-phosphoric (o-H3PO4), sulfuric (H2SO4) and hydrochloric acids (HCl). The GPEs were cross-linked using borax. The polymeric gels were characterized by spectroscopic, thermal, ionic conductivities and dielectric measurements. Proton conductivity was in the range of 5.1 × 10-3 to 3.7 × 10-4 s cm-1 and activation energies were between 0.14 meV and 0.19 meV, at different temperatures. Among the doped acids, the H3PO4 doped GPE exhibited thermal stability at varying temperature. Electrochemical double layer capacitors (EDLCs) were fabricated using activated carbon as electrode material and GPEs. The EDLCs were tested using cyclic voltammetry, ac impedance spectroscopic and galvanostatic charge-discharge techniques. The maximum specific capacitance value was 146 F g-1 at a scan rate of 2 mV s-1. Quite stable values were obtained at a constant current density up to 1000 cycles.

  6. The Chemical Behavior and Degradation Mitigation Effect of Cerium Oxide Nanoparticles in Perfluorosulfonic Acid Polymer Electrolyte Membranes

    SciTech Connect

    Pearman, Benjamin P; Mohajeri, Nahid; Slattery, Darlene; Hampton, Michael; Seal, Sudipta; Cullen, David A

    2013-01-01

    Perfluorosulfonic acid membranes, the polymer of choice for polymer electrolyte hydrogen fuel cells, are susceptible to degradation due to attacks on polymer chains from radicals. Mitigation of this attack by cerium-based radical scavengers is an approach that has shown promise. In this work, two formulations of single-crystal cerium oxide nanoparticles, with an order of magnitude difference in particle size, are incorporated into said membranes and subjected to proton conductivity measurements and ex-situ durability tests. We found that ceria is reduced to Ce(III) ions in the acidic environment of a heated, humidified membrane which negatively impacts proton conductivity. In liquid and gas Fenton testing, fluoride emission is reduced by an order of magnitude, drastically increasing membrane longevity. Side-product analysis demonstrated that in the liquid Fenton test, the main point of attack are weak polymer end groups, while in the gas Fenton test, there is additional side-chain attack. Both mechanisms are mitigated by the addition of the ceria nanoparticles, whereby the extent of the durability improvement is found to be independent of particle size.

  7. Concentration-Purification of Uranium from an Acid Leaching Solution

    NASA Astrophysics Data System (ADS)

    Guettaf, H.; Becis, A.; Ferhat, K.; Hanou, K.; Bouchiha, D.; Yakoubi, K.; Ferrad, F.

    2009-11-01

    Chemical processes for the elaboration of uranium concentrate from uranium ore have been studied. This process is composed of successive units operations: crushing, milling, acid conventional leaching, filtration-washing, purification-concentration by ion exchange resins and uranium precipitation. The acid leaching operating conditions allow us to obtain a recovery uranium rate of 93%. The uranium concentration of the pregnant solution is approximately of 1.2 g/l. This value justifies the use of ion exchange resins to the concentration-purification of our pregnant solution. We have noticed that the pregnant solution contains a relatively high phosphate concentration which causes a premature uranium precipitation at pH=1.8. This pH value is in general, considered optimal to obtain the highest amount of fixed uranium by the anionic resin. To avoid the precipitation of uranium, the pH=1.5 has been fixed. We have obtained at this condition a good adsorption capacity. A 75% uranium concentrate have been elaborated, but the filtration of this concentrate has been very difficult. We have also noticed an excessive sulphate concentration. In order to improve this process, we have tested nitrates as eluant at different operating conditions.

  8. Anodic dissolution of nickel in acidic chloride solutions

    NASA Astrophysics Data System (ADS)

    El Aal, E. E. Abd; Zakria, W.; Diab, A.; El Haleem, S. M. Abd

    2003-04-01

    The anodic dissolution of nickel was studied galvanostatically in hydrochloric acid solutions of various concentrations. The reaction orders of chloride ion and hydrogen ion concentrations were found to be 0.5 and 1.0, respectively. An anodic Tafel slope equal to 120 ± 10 mV · decade-1 was obtained. The dissolution rate of nickel at constant acid concentration was increased with stirring of the solution and increasing temperature. The activation energy, ΔH, for the anodic dissolution process was found to be 12 kcal · mol-1. The presence of oxygen in solutions assisted the passivation process. The effect of addition of aniline and some of its derivatives (o-, m-, and p-anisidine) as inhibitors on the dissolution kinetics of Ni in 1 M HCl was also investigated. These compounds inhibited the anodic dissolution of nickel without affecting the Tafel slope, indicating that the adsorption of such inhibitors could not interfere with the mechanism of metal dissolution.

  9. Polymer Electrolytes

    NASA Astrophysics Data System (ADS)

    Hallinan, Daniel T.; Balsara, Nitash P.

    2013-07-01

    This review article covers applications in which polymer electrolytes are used: lithium batteries, fuel cells, and water desalination. The ideas of electrochemical potential, salt activity, and ion transport are presented in the context of these applications. Potential is defined, and we show how a cell potential measurement can be used to ascertain salt activity. The transport parameters needed to fully specify a binary electrolyte (salt + solvent) are presented. We define five fundamentally different types of homogeneous electrolytes: type I (classical liquid electrolytes), type II (gel electrolytes), type III (dry polymer electrolytes), type IV (dry single-ion-conducting polymer electrolytes), and type V (solvated single-ion-conducting polymer electrolytes). Typical values of transport parameters are provided for all types of electrolytes. Comparison among the values provides insight into the transport mechanisms occurring in polymer electrolytes. It is desirable to decouple the mechanical properties of polymer electrolyte membranes from the ionic conductivity. One way to accomplish this is through the development of microphase-separated polymers, wherein one of the microphases conducts ions while the other enhances the mechanical rigidity of the heterogeneous polymer electrolyte. We cover all three types of conducting polymer electrolyte phases (types III, IV, and V). We present a simple framework that relates the transport parameters of heterogeneous electrolytes to homogeneous analogs. We conclude by discussing electrochemical stability of electrolytes and the effects of water contamination because of their relevance to applications such as lithium ion batteries.

  10. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    SciTech Connect

    Pierce, R.

    2012-02-22

    HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into the H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. For 6 M HNO{sub 3}, 10.5 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2 g/L and 0.25 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}.

  11. Systems solutions by lactic acid bacteria: from paradigms to practice

    PubMed Central

    2011-01-01

    Lactic acid bacteria are among the powerhouses of the food industry, colonize the surfaces of plants and animals, and contribute to our health and well-being. The genomic characterization of LAB has rocketed and presently over 100 complete or nearly complete genomes are available, many of which serve as scientific paradigms. Moreover, functional and comparative metagenomic studies are taking off and provide a wealth of insight in the activity of lactic acid bacteria used in a variety of applications, ranging from starters in complex fermentations to their marketing as probiotics. In this new era of high throughput analysis, biology has become big science. Hence, there is a need to systematically store the generated information, apply this in an intelligent way, and provide modalities for constructing self-learning systems that can be used for future improvements. This review addresses these systems solutions with a state of the art overview of the present paradigms that relate to the use of lactic acid bacteria in industrial applications. Moreover, an outlook is presented of the future developments that include the transition into practice as well as the use of lactic acid bacteria in synthetic biology and other next generation applications. PMID:21995776

  12. Systems solutions by lactic acid bacteria: from paradigms to practice.

    PubMed

    de Vos, Willem M

    2011-08-30

    Lactic acid bacteria are among the powerhouses of the food industry, colonize the surfaces of plants and animals, and contribute to our health and well-being. The genomic characterization of LAB has rocketed and presently over 100 complete or nearly complete genomes are available, many of which serve as scientific paradigms. Moreover, functional and comparative metagenomic studies are taking off and provide a wealth of insight in the activity of lactic acid bacteria used in a variety of applications, ranging from starters in complex fermentations to their marketing as probiotics. In this new era of high throughput analysis, biology has become big science. Hence, there is a need to systematically store the generated information, apply this in an intelligent way, and provide modalities for constructing self-learning systems that can be used for future improvements. This review addresses these systems solutions with a state of the art overview of the present paradigms that relate to the use of lactic acid bacteria in industrial applications. Moreover, an outlook is presented of the future developments that include the transition into practice as well as the use of lactic acid bacteria in synthetic biology and other next generation applications. PMID:21995776

  13. Acid retardation method in analysis of strongly acidic solutions by inductively coupled plasma mass-spectrometry.

    PubMed

    Seregina, I F; Perevoznik, O A; Bolshov, M A

    2016-10-01

    Acid retardation on the sorbents as a technique for reduction of the acidity of the solutions prior to their analysis by inductively coupled plasma mass spectrometry was proposed and investigated. The proposed scheme provides substantial separation of the analytes and nitric acid, which allows direct introduction of the eluates in plasma without dilution. Two sorbents were examined - AV-17 anion-exchange resin and the Stirosorb 584 sorbent. Sorption and desorption of 38 elements on these sorbents were investigated. The efficiencies of the REEs' sorption on the anion-exchange and neutral sorbents were compared. The higher efficiency of the REEs and HNO3 separation was revealed for the neutral Stirosorb 584 sorbent. It was also found that most elements come out quantitatively of the column filled with the AV-17 resin after pumping 2-4mL of the solution. Wherein, the concentration of nitric acid decreased by 20 times. The anomalous behaviour of Ag, Pb, Th and U on the AV-17 resin was found. These analytes were eluted only after pumping 4 column volumes of deionized water. Na, K, Fe, Al and Li in concentrations within (50-1000mgL(-1)) range did not affect the recovery of REEs. The potential of ARM technique was demonstrate by the analysis of puriss. HNO3 and silverware. ARM enables to avoid dilution of highly acidic solutions prior to their introduction in ICP-MS. PMID:27474322

  14. Effects of acidic solutions on sexual reproduction of Pteridium aquilinum

    SciTech Connect

    Evans, L.S.; Conway, C.A.

    1980-01-01

    Experiments were performed to determine the effects of acidic solutions on spermatozoid motility and fertilization of gametophytes of Pteridium aquilinum. Buffered solutions (approx 0.0025 m) were used to simulate exposures to acidic precipitation for up to a 3.5 hr exposure. Experimental results suggest that the spermatozoid population can be subdivided into several groups with respect to pH sensitivity: About 25% spermatozoids are immobile one min after exposure to pH 6.1 buffer while about an equal percentage remain motile after 30 min exposure to buffer of pH 5.1. Between these two response extremes are two other subpopulations. One is quite sensitive to pH but shows some recovery if pH is between 5.6 and 6.1, while the second subpopulation does not seem to exhibit any motility recovery at all but is more resistant to acidity than the first subpopulation. To complement experiments that evaluate spermatozoid responses, experiments were performed to view the process of fertilization under controlled environmental conditions as well as under the canopy of a forest. Fertilization of gametophytes in uncovered petri dishes under a forest canopy was similar to results in aseptic culture after gametophytes were exposed to various pH levels and 86.6 micrometers sulfate. Fertilization at pH 4.5 and 3.6 was about one-half that occurring at pH 6.1. Fertilization in gametophytes exposed to pH 3.0 was about 10-20% of that occurring at pH 6.1. Addition of 86.6 micrometers sulfate decreased fertilization under all culture conditions. These experimental results suggest that fertilization in p. Aquilinum may be used as a bioindicator of contaminants in rainwater. The results demonstrate that spermatozoid motility (and the process of fertilization) is more acid sensitive than gametophytic and sporophytic tissues.

  15. Excellent stability of a lithium-ion-conducting solid electrolyte upon reversible Li+/H+ exchange in aqueous solutions

    SciTech Connect

    Ma, Cheng; Rangasamy, Ezhiylmurugan; Liang, Chengdu; Sakamoto, Jeffrey; More, Karren Leslie; Chi, Miaofang

    2014-10-21

    Batteries with an aqueous catholyte and a Li metal anode have attracted interest owing to their exceptional energy density and high charge/discharge rate. The long-term operation of such batteries requires that the solid electrolyte separator between the anode and aqueous solutions must be compatible with Li and stable over a wide pH range. Unfortunately, no such compound has yet been reported. In this study, an excellent stability in neutral and strongly basic solutions was observed when using the cubic Li7La3Zr2O12 garnet as a Li-stable solid electrolyte. The material underwent a Li+/H+ exchange in aqueous solutions. Nevertheless, its structure remained unchanged even under a high exchange rate of 63.6%. When treated with a 2 M LiOH solution, the Li+/H+ exchange was reversed without any structural change. Furthermore, these observations suggest that cubic Li7La3Zr2O12 is a promising candidate for the separator in aqueous lithium batteries.

  16. Reduction of hexavalent chromium by ascorbic acid in aqueous solutions.

    PubMed

    Xu, Xiang-Rong; Li, Hua-Bin; Li, Xiao-Yan; Gu, Ji-Dong

    2004-11-01

    Hexavalent chromium is a priority pollutant in the USA and many other countries. Reduction of Cr(VI) to Cr(III) is environmentally favorable as the latter species is not toxic to most living organisms and also has a low mobility and bioavailability. Reduction of Cr(VI) by ascorbic acid (vitamin C) as a reductant was studied using potassium dichromate solution as the model pollutant. Effects of concentration of vitamin C, pH, temperature, irradiation and reaction time on the reduction of Cr(VI) were examined. Cr(VI) might be reduced by vitamin C not only in acidic conditions but also in weakly alkaline solutions. The reduction of Cr(VI) by vitamin C might occur not only under irradiation but also in the dark. Vitamin C is an important biological reductant in humans and animals, and not toxic. It is water-soluble and can easily permeate through various types of soils. The results indicate that vitamin C could be used in effective remediation of Cr(VI)-contaminated soils and groundwater in a wide range of pH, with or without sunlight. PMID:15488923

  17. Infrared optical constants of H2O ice, amorphous nitric acid solutions, and nitric acid hydrates

    NASA Technical Reports Server (NTRS)

    Toon, Owen B.; Koehler, Birgit G.; Middlebrook, Ann M.; Tolbert, Margaret A.; Jordon, Joseph

    1994-01-01

    We determined the infrared optical constants of nitric acid trihydrate, nitric acid dihydrate, nitric acid monohydrate, and solid amorphous nitric acid solutions which crystallize to form these hydrates. We have also found the infrared optical constants of H2O ice. We measured the transmission of infrared light throught thin films of varying thickness over the frequency range from about 7000 to 500/cm at temperatures below 200 K. We developed a theory for the transmission of light through a substrate that has thin films on both sides. We used an iterative Kramers-Kronig technique to determine the optical constants which gave the best match between measured transmission spectra and those calculated for a variety of films of different thickness. These optical constants should be useful for calculations of the infrared spectrum of polar stratospheric clouds.

  18. Removal of arsenious acid from sulfuric acidic solution using ultrasound oxidation and goethite

    NASA Astrophysics Data System (ADS)

    Okawa, Hirokazu; Yoshikawa, Tomohiro; Hosokawa, Ryota; Hangui, Shinji; Kawamura, Youhei; Sugawara, Katsuyasu

    2015-07-01

    We investigated the properties of synthetic goethite for the adsorption of As from strongly acidic solutions in ambient atmosphere under ultrasound irradiation. The goethite was successfully synthesized from iron-containing sulfuric acidic solution (1271 ppm) using an autoclave apparatus for 1 h at 0.12 MPa and 121 °C. The ratio of the iron eluted from the synthetic goethite to the acidic solution was only 0.58% at pH 2.1. Ultrasound irradiation (200 kHz, 200 W) was applied to oxidize 10 ppm of As(III) to As(V) at pH 2.2 for 60 min under various atmospheric conditions. Remarkably, the oxidation ratio of As(III) to As(V) is quite high (89.7%) at pH 2.2 in ambient atmosphere and is close to those obtained for Ar (95.3%) and O2 (95.9%) atmospheres. The As(III) removal ratio reached 94.5% after 60 min of irradiation. Therefore, goethite is a promising material for As adsorption using ultrasound oxidation in the acidic region in ambient atmosphere.

  19. Interaction between like-charged polyelectrolyte-colloid complexes in electrolyte solutions: A Monte Carlo simulation study in the Debye-Hückel approximation

    NASA Astrophysics Data System (ADS)

    Truzzolillo, D.; Bordi, F.; Sciortino, F.; Sennato, S.

    2010-07-01

    We study the effective interaction between differently charged polyelectrolyte-colloid complexes in electrolyte solutions via Monte Carlo simulations. These complexes are formed when short and flexible polyelectrolyte chains adsorb onto oppositely charged colloidal spheres, dispersed in an electrolyte solution. In our simulations the bending energy between adjacent monomers is small compared to the electrostatic energy, and the chains, once adsorbed, do not exchange with the solution, although they rearrange on the particles surface to accommodate further adsorbing chains or due to the electrostatic interaction with neighbor complexes. Rather unexpectedly, when two interacting particles approach each other, the rearrangement of the surface charge distribution invariably produces antiparallel dipolar doublets that invert their orientation at the isoelectric point. These findings clearly rule out a contribution of dipole-dipole interactions to the observed attractive interaction between the complexes, pointing out that such suspensions cannot be considered dipolar fluids. On varying the ionic strength of the electrolyte, we find that a screening length κ-1, short compared with the size of the colloidal particles, is required in order to observe the attraction between like-charged complexes due to the nonuniform distribution of the electric charge on their surface ("patch attraction"). On the other hand, by changing the polyelectrolyte/particle charge ratio ξs, the interaction between like-charged polyelectrolyte-decorated particles, at short separations, evolves from purely repulsive to strongly attractive. Hence, the effective interaction between the complexes is characterized by a potential barrier, whose height depends on the net charge and on the nonuniformity of their surface charge distribution.

  20. Arsenic removal from acidic solutions with biogenic ferric precipitates.

    PubMed

    Ahoranta, Sarita H; Kokko, Marika E; Papirio, Stefano; Özkaya, Bestamin; Puhakka, Jaakko A

    2016-04-01

    Treatment of acidic solution containing 5g/L of Fe(II) and 10mg/L of As(III) was studied in a system consisting of a biological fluidized-bed reactor (FBR) for iron oxidation, and a gravity settler for iron precipitation and separation of the ferric precipitates. At pH 3.0 and FBR retention time of 5.7h, 96-98% of the added Fe(II) precipitated (99.1% of which was jarosite). The highest iron oxidation and precipitation rates were 1070 and 28mg/L/h, respectively, and were achieved at pH 3.0. Subsequently, the effect of pH on arsenic removal through sorption and/or co-precipitation was examined by gradually decreasing solution pH from 3.0 to 1.6 (feed pH). At pH 3.0, 2.4 and 1.6, the highest arsenic removal efficiencies obtained were 99.5%, 80.1% and 7.1%, respectively. As the system had ferric precipitates in excess, decreased arsenic removal was likely due to reduced co-precipitation at pH<2.4. As(III) was partially oxidized to As(V) in the system. In shake flask experiments, As(V) sorbed onto jarosite better than As(III). Moreover, the sorption capacity of biogenic jarosite was significantly higher than that of synthetic jarosite. The developed bioprocess simultaneously and efficiently removes iron and arsenic from acidic solutions, indicating potential for mining wastewater treatment. PMID:26705889

  1. Electrocatalytic activities of cathode electrodes for water electrolysis using tetra-alkyl-ammonium-sulfonic acid ionic liquid as electrolyte

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    The hydrogen evolution reaction (HER) performed with platinum (Pt), nickel (Ni), stainless steel 304 (SS) or glassy carbon (GC) cathodes in 0.1 M 3-triethylammonium-propanesulfonic acid tetrafluoroborate (TEA-PS.BF4) solution is studied using quasi-potentiostatic and impedance spectroscopy techniques. The objective is to compare the catalytic effect on the cathode using different materials to obtain hydrogen by water electrolysis. Furthermore, the catalytic effect of the ionic liquid (IL) on the cathode compared with that of a hydrochloric acid (HCl) solution with same pH value (0.8) is reported. A low activation energy (Ea) of 8.7 kJ mol-1 is found for the glassy carbon cathode. Tafel plots obtained with TEA-PS.BF4 IL suggest the formation of an electroactive layer of IL on the cathode, which may be responsible for the catalytically enhanced performance observed.

  2. Hydrogen production by photoelectrochemically splitting solutions of formic acid.

    PubMed

    Li, Lei; Guo, Wenliang; Zhu, Yusong; Wu, Yuping

    2011-10-17

    A TiO₂/FTO (FTO=fluorine-doped tin oxide) electrode was prepared by dip-coating FTO in a suspension of TiO₂ prepared from a sol-gel method and was used as a photoanode to split an aqueous solution of formic acid to produce hydrogen. The surface of the TiO₂/FTO film was covered with assemblies of TiO₂ nanoparticles with a diameter of approximately 20 nm. Under irradiation by using a Xe lamp, splitting of formic acid was performed at different applied current densities. Compared to splitting water or utilizing FTO and Pt foil as the anode, the splitting voltage is much lower and can be as low as -0.27 V. The results show that the splitting voltage is related to the concentration of free formate groups. The evolution rate of hydrogen measured by using gas chromatography is 130 μmol h⁻¹ at a current density of 20 mA cm⁻² and the energy-conversion efficiency can be 1.79 %. Photoelectrolysis of formic acid has the potential to be an efficient way to produce hydrogen with a high energy-conversion efficiency. PMID:21994155

  3. Conformation of poly(γ-glutamic acid) in aqueous solution.

    PubMed

    Muroga, Yoshio; Nakaya, Asami; Inoue, Atsuki; Itoh, Daiki; Abiru, Masaya; Wada, Kaori; Takada, Masako; Ikake, Hiroki; Shimizu, Shigeru

    2016-04-01

    Local conformation and overall conformation of poly(γ-DL-glutamic acid) (PγDLGA) and poly(γ-L-glutamic acid) (PγLGA) in aqueous solution was studied as a function of degree of ionization ε by (1) H-NMR, circular dichroism, and potentiometric titration. It was clarified that their local conformation is represented by random coil over an entire ε range and their overall conformation is represented by expanded random-coil in a range of ε > ε(*) , where ε(*) is about 0.3, 0.35, 0.45, and 0.5 for added-salt concentration of 0.02M, 0.05M, 0.1M, and 0.2M, respectively. In a range of ε < ε(*) , however, ε dependence of their overall conformation is significantly differentiated from each other. PγDLGA tends to aggregate intramolecularly and/or intermolecularly with decreasing ε, but PγLGA still behaves as expanded random-coil. It is speculated that spatial arrangement of adjacent carboxyl groups along the backbone chain essentially affects the overall conformation of PγGA in acidic media. PMID:26574908

  4. Voltammetry and conductivity of a polyether-pyridinium room temperature molten salt electrolyte and of its polymer electrolyte solutions in polydimethylsiloxane

    SciTech Connect

    Pyati, R.; Murray, R.W.

    1996-02-01

    This report describes the synthesis, microelectrode voltammetry, and ionic conductivity of a new room temperature molten salt N-(methoxy(ethoxy){sub 2}ethyl)pyridinium p-toluene sulfonate (abbreviated as[Py(E{sub 3}M){sup +}][Tos{sup {minus}}]) and of its solution in a hydroxy-terminated polydimethylsiloxane. Both ionically conductive liquids (conductivity = 1 {times} 10{sup {minus}4} {Omega}{sup {minus}1} cm{sup {minus}1}) exhibit voltammetric potential windows of about 1.5 V. The negative potential limit is determined by the reduction of the [Py(E{sub 3}M){sup +}] pyridinium species, with subsequent radical coupling to form a voltammetrically observed viologen dimer. The estimated diffusivities of the [Py(E{sub 3}M){sup +}] species, of a diethyleneglycol-tailed ferrocene redox solute studied, and by application of Nernst-Einstein relation to the ionic charge carriers, all lie in the 10{sup {minus}7} to 10{sup {minus}8} cm{sup 2}/s range. Viscosities and glass transition thermal observations are reported as is the fit of the temperature dependencies of ionic conductivity in [Py(E{sub 3}M){sup +}][Tos{sup {minus}}] and in [Py(E{sub 3}M){sup +}][TOS{sup {minus}}]/PDMS mixtures to Vogel-Tamman-Fulcher predictions.

  5. Solid Polymer Electrolytes Based on Functionalized Tannic Acids from Natural Resources for All-Solid-State Lithium-Ion Batteries.

    PubMed

    Shim, Jimin; Bae, Ki Yoon; Kim, Hee Joong; Lee, Jin Hong; Kim, Dong-Gyun; Yoon, Woo Young; Lee, Jong-Chan

    2015-12-21

    Solid polymer electrolytes (SPEs) for all-solid-state lithium-ion batteries are prepared by simple one-pot polymerization induced by ultraviolet (UV) light using poly(ethylene glycol) methyl ether methacrylate (PEGMA) as an ion-conducting monomeric unit and tannic acid (TA)-based crosslinking agent and plasticizer. The crosslinking agent and plasticizer based on natural resources are obtained from the reaction of TA with glycidyl methacrylate and glycidyl poly(ethylene glycol), respectively. Dimensionally stable free-standing SPE having a large ionic conductivity of 5.6×10(-4)  Scm(-1) at room temperature can be obtained by the polymerization of PEGMA into P(PEGMA) with a very small amount (0.1 wt %) of the crosslinking agent and 2.0 wt % of the plasticizer. The ionic conductivity value of SPE with a crosslinked structure is one order of magnitude larger than that of linear P(PEGMA) in the waxy state. PMID:26609912

  6. Creatinine, urea, uric acid, water and electrolytes renal handling in the healthy oldest old

    PubMed Central

    Musso, Carlos Guido; Álvarez Gregori, Joaquín; Jauregui, José Ricardo; Macías Núñez, Juan Florencio

    2012-01-01

    Renal physiology in the healthy oldest old has the following characteristics, in comparison with the renal physiology in the young: a reduced creatinine clearance, tubular pattern of creatinine back-filtration, preserved proximal tubule sodium reabsorption and uric acid secretion, reduced sodium reabsorption in the thick ascending loop of Henle, reduced free water clearance, increased urea excretion, presence of medulla hypotonicity, reduced urinary dilution and concentration capabilities, and finally a reduced collecting tubules response to furosemide which expresses a reduced potassium excretion in this segment due to a sort of aldosterone resistance. All physiological changes of the aged kidney are the same in both genders. PMID:24175249

  7. Electrolytes Test

    MedlinePlus

    ... include other tests such as BUN , creatinine , and glucose . Electrolyte measurements may be used to help investigate conditions that cause electrolyte imbalances such as dehydration , kidney disease , lung diseases , or heart conditions . Repeat testing may then ...

  8. Potential Use of Lime as Nitric Acid Source for Alternative Electrolyte Fuel-Cell Method

    NASA Astrophysics Data System (ADS)

    Christianto, V.; Smarandache, Florentin

    2011-04-01

    Despite growing popularity for the use of biofuel and other similar methods to generate renewable energy sources from natural plantation in recent years, there is also growing concern over its disadvantage, i.e. that the energy use of edible plants may cause unwanted effects, because the plantation price tends to increase following the oil price. Therefore an alternative solution to this problem is to find `natural plantation' which have no direct link to `food chain' (for basic foods, such as palm oil etc.).

  9. INTERACTION OF AQUEOUS SOLUTIONS OF CHLORINE WITH MALIC ACID, TARTARIC ACID, AND VARIOUS FRUIT JUICES, A SOURCE OF MUTAGENS

    EPA Science Inventory

    The interactions of aqueous solutions of chlorine with some fruit acids (citric acid, DL-malic acid, and L-tartaric acid) at different pH values were studied. iethyl ether extraction followed by GC/MS analysis indicated that a number of mutagens (certain chlorinated propanones an...

  10. Jacques Loeb (1859-1924) and His Forgotten Contributions to Electrolyte and Acid-Base Physiology in The Organism as a Whole.

    PubMed

    Sgambato, Francesco; Sgambato, Ester; De Santo, Natale Gaspare

    2016-02-01

    Jacques Loeb (1859-1924) was the founder of the Journal of General Physiology which he co-directed in association with W.J.V. Osterhout in the years 1918-1924. Having worked (1889-1891)at the Marine Zoological Station of Naples, newly founded by Anton Dohrn, he was imprinted for life. A strong investigator used to perform the experiments personally. Loeb was engaged lifelong in the explanation of life on physico-chemical basis. He touched various fields (being a creative scientist full of ideas), and centered on the exchanges of electrolytes, acids and bases between the body and sea water in fish. He identified two equations: {[K+]+[Na+]}: {[Ca++]+[Mg++]} (Loebs 1st equation) {[K+]+[Na+]}: {[H+]+[Ca++]+[Mg++]} (Loebs final equation) Even nowadays these equations may have applications in a wide list of electrolyte and acid-base disturbances. Unfortunately his heredity has been dissipated. PMID:26913896

  11. The extraction of actinides from nitric acid solutions with diamides of dipicolinic acid

    NASA Astrophysics Data System (ADS)

    Lapka, Joseph L.; Paulenova, Alena; Alyapyshev, Mikhail Yu; Babain, Vasiliy A.; Law, Jack D.; Herbst, R. Scott

    2010-03-01

    Diamides of dipicolinic acid (N,N'-diethyl-N,N'-ditolyl-dipicolinamide, EtTDPA) were synthesized and evaluated for their extraction capability for actinides. In this work the extractions of neptunium(V), protactinium(V), and thorium(IV) with EtTDPA in a polar fluorinated diluent from nitric acid were investigated. EtTDPA shows a high affinity for Th(IV) even at millimolar concentrations. Np(V) and Pa(V) are both reasonably extractable with EtTDPA; however, near saturated solutions are required to achieve appreciable distribution ratios. A comparison with previously published actinide extraction data is given.

  12. Electrochemically stable electrolytes

    DOEpatents

    Angell, Charles Austen; Zhang, Sheng-Shui; Xu, Kang

    1999-01-01

    This invention relates generally to inorganic ionic liquids which function as electrolytes and do not crystallize at ambient temperature. More specifically, this invention is directed to quasi-salt inorganic ionic liquids which comprise the reaction product of a strong Lewis acid with an inorganic halide-donating molecule. This invention is further directed to quasi-salt inorganic ionic liquid mixtures which comprise combinations of electrolyte additives and quasi-salt inorganic ionic liquids. These quasi-salt inorganic ionic liquid mixtures are useful electrolytes.

  13. Electrochemically stable electrolytes

    DOEpatents

    Angell, C.A.; Zhang, S.S.; Xu, K.

    1999-01-05

    This invention relates generally to inorganic ionic liquids which function as electrolytes and do not crystallize at ambient temperature. More specifically, this invention is directed to quasi-salt inorganic ionic liquids which comprise the reaction product of a strong Lewis acid with an inorganic halide-donating molecule. This invention is further directed to quasi-salt inorganic ionic liquid mixtures which comprise combinations of electrolyte additives and quasi-salt inorganic ionic liquids. These quasi-salt inorganic ionic liquid mixtures are useful electrolytes. 16 figs.

  14. Electrolyte salts for power sources

    DOEpatents

    Doddapaneni, N.; Ingersoll, D.

    1995-11-28

    Electrolyte salts are disclosed for power sources comprising salts of phenyl polysulfonic acids and phenyl polyphosphonic acids. The preferred salts are alkali and alkaline earth metal salts, most preferably lithium salts. 2 figs.

  15. Standardized diagnosis and treatment of fluid, acid-base and electrolyte disorders in the surgical patient with the aid of a programmable pocket calculator.

    PubMed

    Kievit, J

    1983-05-01

    The approach to fluid, acid-base and electrolyte disorders in the surgical patient has been standardized in a pocket calculator program that categorizes these disorders into formal diagnoses and subsequently uses these diagnoses to determine the appropriate therapy. The program was tested in 80 infusion regimens of patients in the intensive care and surgical wards. The advantages of a standardized approach to these disorders, using diagnostic and therapeutic algorithms, are briefly discussed. PMID:6342704

  16. Exact solution of the unidimensional Poisson-Boltzmann equation for a 1:2 (2:1) electrolyte.

    PubMed Central

    Andrietti, F; Peres, A; Pezzotta, R

    1976-01-01

    The unidimensional Poisson-Boltzmann equation for a 1:2 (2:1) electrolyte has been solved analytically. The results have been compared with those obtained from the linearized equation. It is shown that in physiological conditions the difference may be greater than 10%. The value of the derivative of the potential in x=0, (dpsi/dx)x=0, has been used by many authors in the evaluation of the superficial charges of biological membranes. The value of (dpsi/dx)x-0 have also been compared with the ones derived from the linearized equation. The difference may be greater than 25%. Our results suggest that the linearization of the Poisson-Boltzmann equation for a 1:2(2:1) electrolyte may be greatly misleading. PMID:963209

  17. Corrosion resistance of flaky aluminum pigment coated with cerium oxides/hydroxides in chloride and acidic electrolytes

    NASA Astrophysics Data System (ADS)

    Niroumandrad, S.; Rostami, M.; Ramezanzadeh, B.

    2015-12-01

    The objective of this study was to enhance the corrosion resistance of lamellar aluminum pigment through surface treatment by cerium oxides/hydroxides. The surface composition of the pigments was studied by energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of the pigment was evaluated by conventional hydrogen evolution measurements in acidic solution and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. Results showed that the Ce-rich coating composed of Ce2O3 and CeO2 was precipitated on the pigment surface after immersion in the cerium solution. The corrosion resistance of pigment was significantly enhanced after modification with cerium layer.

  18. The effect of concentration- and temperature-dependent dielectric constant on the activity coefficient of NaCl electrolyte solutions

    SciTech Connect

    Valiskó, Mónika; Boda, Dezső

    2014-06-21

    Our implicit-solvent model for the estimation of the excess chemical potential (or, equivalently, the activity coefficient) of electrolytes is based on using a dielectric constant that depends on the thermodynamic state, namely, the temperature and concentration of the electrolyte, ε(c, T). As a consequence, the excess chemical potential is split into two terms corresponding to ion-ion (II) and ion-water (IW) interactions. The II term is obtained from computer simulation using the Primitive Model of electrolytes, while the IW term is estimated from the Born treatment. In our previous work [J. Vincze, M. Valiskó, and D. Boda, “The nonmonotonic concentration dependence of the mean activity coefficient of electrolytes is a result of a balance between solvation and ion-ion correlations,” J. Chem. Phys. 133, 154507 (2010)], we showed that the nonmonotonic concentration dependence of the activity coefficient can be reproduced qualitatively with this II+IW model without using any adjustable parameter. The Pauling radii were used in the calculation of the II term, while experimental solvation free energies were used in the calculation of the IW term. In this work, we analyze the effect of the parameters (dielectric constant, ionic radii, solvation free energy) on the concentration and temperature dependence of the mean activity coefficient of NaCl. We conclude that the II+IW model can explain the experimental behavior using a concentration-dependent dielectric constant and that we do not need the artificial concept of “solvated ionic radius” assumed by earlier studies.

  19. Formation of Porous Anodic Oxide Film on Titanium in Phosphoric Acid Electrolyte

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Thompson, G. E.

    2015-01-01

    A sequential breakdown anodizing conditions on cp-Ti in phosphoric acid has been investigated in the present study. Anodic oxide films were formed at 100, 150, and 200 V, examined by scanning electron microscopy, Raman spectroscopy, glow discharge optical emission spectrometry, and electrochemical impedance spectroscopy. A porous oxide texture was formed at each voltage. The thickness of anodic porous oxide increased with the increase of anodic voltage. Nano-particulates were formed around and within the pores, and the size of pores increased with increased voltage due to the expansion of particulates. The amorphous-to-crystalline transition was initiated during the film growth. The degree of crystallinity in the anodic oxide film fabricated at 200 V is more abundant than 150 and 100 V. Increased content of the phosphorus species was incorporated into the porous film with the increase of anodic voltage, stabilizing for the nanocrystals developed within the oxide.

  20. Split-dose vs same-day reduced-volume polyethylene glycol electrolyte lavage solution for morning colonoscopy

    PubMed Central

    Chan, Wah-Kheong; Azmi, Najib; Mahadeva, Sanjiv; Goh, Khean-Lee

    2014-01-01

    AIM: To compare same-day whole-dose vs split-dose of 2-litre polyethylene glycol electrolyte lavage solution (PEG-ELS) plus bisacodyl for colon cleansing for morning colonoscopy. METHODS: Consecutive adult patients undergoing morning colonoscopy were allocated into two groups i.e., same-day whole-dose or split-dose of 2-litre PEG-ELS. Investigators and endoscopists were blinded to the allocation. All patients completed a questionnaire that was designed by Aronchick and colleagues to assess the tolerability of the bowel preparation regime used. In addition, patients answered an ordinal five-value Likert scale question on comfort level during bowel preparation. Endoscopists graded the quality of bowel preparation using the Boston bowel preparation scale (BBPS). In addition, endoscopists gave an overall grading of the quality of bowel preparation. Cecal intubation time, withdrawal time, total colonoscopy time, adenoma detection rate and number of adenomas detected for each patient were recorded. Sample size was calculated using an online calculator for binary outcome non-inferiority trial. Analyses was based upon intent-to-treat. Significance was assumed at P-value < 0.05. RESULTS: Data for 295 patients were analysed. Mean age was 62.0 ± 14.4 years old and consisted of 50.2 % male. There were 143 and 152 patients in the split-dose and whole-dose group, respectively. Split-dose was as good as whole-dose for quality of bowel preparation. The total BBPS score was as good in the split-dose group compared to the whole-dose group [6 (6-8) vs 6 (6-7), P = 0.038]. There was no difference in cecal intubation rate, cecal intubation time, withdrawal time, total colonoscopy time and adenoma detection rate. Median number of adenoma detected was marginally higher in the split-dose group [2 (1-3) vs 1 (1-2), P = 0.010]. Patients in the whole-dose group had more nausea (37.5% vs 25.2%, P = 0.023) and vomiting (16.4% vs 8.4%, P = 0.037), and were less likely to complete the bowel

  1. [Effects of Low-Molecular-Weight Organic Acids on the Speciation of Pb in Purple Soil and Soil Solution].

    PubMed

    Liu, Jiang; Jiang, Tao; Huang, Rong; Zhang, Jin-zhong; Chen, Hong

    2016-04-15

    Lead (Pb) in purple soil was selected as the research target, using one-step extraction method with 0.01 mol · L⁻¹ sodium nitrate as the background electrolyte to study the release effect of citric acid (CA), tartaric acid (TA) and acetic acid (AC) with different concentrations. Sequential extraction and geochemical model (Visual Minteq v3.0) were applied to analyze and predict the speciation of Pb in soil solid phase and soil solution phase. Then the ebvironmental implications and risks of low-molecule weight organic acid (LMWOA) on soil Pb were analyzed. The results indicated that all three types of LMWOA increased the desorption capacity of Pb in purple soil, and the effect followed the descending order of CA > TA > AC. After the action of LMWOAs, the exchangeable Pb increased; the carbonate-bound Pb and Fe-Mn oxide bound Pb dropped in soil solid phase. Organic bound Pb was the main speciation in soil solution phase, accounting for 45.16%-75.05%. The following speciation of Pb in soil solution was free Pb, accounting for 22.71%-50.25%. For CA and TA treatments, free Pb ions and inorganic bound Pb in soil solution increased with increasing LMWOAs concentration, while organic bound Pb suffered a decrease in this process. An opposite trend for AC treatment was observed compared with CA and TA treatments. Overall, LMWOAs boosted the bioavailability of Pb in purple soil and had a potential risk to contaminate underground water. Among the three LMWOAs in this study, CA had the largest potential to activate soil Pb. PMID:27548978

  2. Radiolysis gases from nitric acid solutions containing HSA and HAN

    SciTech Connect

    Smith, J.R.

    1994-10-28

    The concentration of hydrogen (H{sub 2}) in the radiolytically produced off-gas from 2.76-4.25M HNO{sub 3}/PU solutions has been found to be greatly reduced in the presence of sulfamic acid (HSA) and hydroxylamine nitrate (HAN). The H{sub 2} concentration ([H{sub 2}]) is reduced from 35 percent to about 4 percent by dilution caused from an increase in the production rates of nitrogen (N{sub 2}), nitrous oxide (N{sub 2}O), and oxygen (O{sub 2}) gases. The generation rate of H{sub 2} was not affected by HSA or HAN giving a measured radiolytic yield, G(H{sub 2}), value of 0.201 molecules/100 eV for 2.765M NO{sub 3}{sup -} solution (a value of 0.213 is predicted from previous data). The G(H{sub 2}) values are dependent on the solution nitrate concentration ([NO{sub 3}{sup -}]). The generation rates of N{sub 2}, N{sub 2}O, and O{sub 2} are not dependent on the [NO{sub 3}{sup -}] in this narrow range, but are dependent on the presence of HSA and the concentration of HAN. The percentage [H{sub 2}] for the 2.5 to 3.0M NO{sub 3}{sup -} range expected in the off- from the FB-Line Pu{sup +3} Hold Tanks is conservatively estimated to be about 3.5 to 4.5 % for Pu + 3 solutions initially containing 0.023M HAN/0.165M HSA. The upper limit [H{sub 2}] may actually be about 4.1 % (4.3 % at 90 % confidence limits) but more {open_quotes}initial{close_quotes} off-gas rate data is needed at about 2.9M [NO{sub 3}{sup -}] in Pu{sup +3} solution for verification. Addition of ascorbic acid had no effect on the off-gas rate of Pu{sup +3} solutions containing HSA and NO{sub 3}{sup -} concentrations higher than those expected in the hold tanks. The maximum {open_quotes}hold time{close_quotes} for 50 grams/liter Pu{sup +3}/0.165M HSA/0.023M HAN/2.5-3.0M HNO{sub 3} solution is 20.3{+-}2.1 days. After this time the HSA initially present will become exhausted and the [H{sub 2}] will increase to 35 %. This hold time may be longer in [NO{sub 3}{sup -}] < 3.0M, but again more study is needed.

  3. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    SciTech Connect

    Pierce, R. A.

    2012-03-12

    HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into the H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 °C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. At 25 °C, for 6 M HNO{sub 3}, 11 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2.5 g/L and 0.8 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}. The solubility of Gd in 4 M HNO{sub 3} with 0.15 M oxalate at 10 °C is about 1.5 g/L. For 6 M HNO{sub 3} with 0.15 M oxalate, the solubility of Gd at 10

  4. Optical properties of chitosan in aqueous solution of L- and D-ascorbic acids

    NASA Astrophysics Data System (ADS)

    Malinkina, Olga N.; Shipovskaya, Anna B.; Kazmicheva, Olga F.

    2016-04-01

    The optical properties of aqueous chitosan solutions in L- and D-ascorbic acids were studied by optical rotatory dispersion and spectrophotometry. The specific optical rotation [α] of all chitosan solutions tested was positive, in contrast to aqueous solutions of the ascorbic acid enantiomers, which exhibit an inverse relationship of [α] values. Significant differences in the absolute values of [α] of the chitosan solutions at polymer-acid ratios exceeding the equimolar one were found.

  5. Planetary resources and astroecology. Planetary microcosm models of asteroid and meteorite interiors: electrolyte solutions and microbial growth--implications for space populations and panspermia.

    PubMed

    Mautner, Michael N

    2002-01-01

    Planetary microcosms were constructed using extracts from meteorites that simulate solutions in the pores of carbonaceous chondrites. The microcosms were found to support the growth of complex algal and microbial populations. Such astroecology experiments demonstrate how a diverse ecosystem could exist in fluids within asteroids, and in meteorites that land on aqueous planets. The microcosm solutions were obtained by extracting nutrient electrolytes under natural conditions from powders of the Allende (CV3) and Murchison (CM2) meteorites at low (0.02 g/ml) and high (10.0 g/ml) solid/solution ratios. The latter solutions contain > 3 mol/L electrolytes and about 10 g/L organics, that simulate natural fluids in asteroids during aqueous alteration and in the pores of meteorites, which can help prebiotic synthesis and the survival of early microorganisms. These solutions and wet solids were in fact found to support complex self-sustaining microbial communities with populations of 4 x 10(5) algae and 6 x 10(6) bacteria and fungi for long periods (> 8 months). The results show that planetary microcosms based on meteorites can: assay the fertilities of planetary materials; identify space bioresources; target astrobiology exploration; and model past and future space-based ecosystems. The results show that bioresources in the carbonaceous asteroids can sustain a biomass of 10(18) kg, comprising 10(32) microorganisms and a human population of 10(14). The results also suggest that protoplanetary nebulae can support and disperse microorganisms and can be therefore effective environments for natural and directed panspermia. PMID:12449855

  6. Electrorefining of copper from a cuprous ion complexing electrolyte. II. Experimental comparison of possible alternative electrolytes and preliminary cost engineering analysis

    SciTech Connect

    Brown, A.P.; Loutfy, R.O.; Cook, G.M.

    1980-04-01

    The energy saving potential and refining capability of three copper(I)/electrolyte systems for the electrorefining of copper were compared experimentally. The alternative electrolyte systems studied were copper(I)/acid chloride, copper(I)/acetonitrile and sulfuric acid, and copper(I)/ammonia solutions. These were compared to the conventional copper(II)/sulfuric acid electrolyte. All of the alternative electrolyte systems demonstrated at least some potential for saving energy when run at an equal deposition rate to the conventional process; the chloride electrolyte showed the greatest energy saving potential, about 70%, and the ammonia electrolyte showed the least, about 25%. All of the alternative electrolyte systems, however, exhibited performance problems, primarily with regard to inadequate separation of impurities. A preliminary capital cost estimate was made for the copper(I)/chloride system. This estimate showed that, for the alternative electrolyte system to be cost competitive (that is, a reduction of capital cost of about 15 to 20%) with the conventional electrorefining process, the refining cells would have to be operated at a current density of about 25 to 30 mA-cm/sup -2/. At this current density, the estimated energy saving potential for the copper(I)/chloride system was still about 50%.

  7. Germicide wound pad with active, in situ, electrolytically produced hypochlorous acid.

    PubMed

    Rubinsky, L; Patrick, B; Mikus, P; Rubinsky, B

    2016-04-01

    We describe a new wound dressing technology that can actively generate an inorganic germicide agent, in situ, within the wound pad. The technology provides real time control over the quantitative, spatial and temporal delivery of the germicide. The identity of the germicide is hypochlorous acid (HClO). The HClO is produced in a flexible wound pad, made of a composite of thin (micrometer scale) layers of various materials, with different electrochemical properties that enhance HClO production. Active control over the production of HClO is achieved by control of the pH and of the electric potential across the layers. The effectiveness of the Active HClO Pad (AHClOP) concept is demonstrated in a study on sterilization of E. coli in a deep wound contamination simulating gel. The performance of the AHClOP is compared with that of four commercial wound dressings. Results show that the AHClOP can sterilize throughout the gel, while the commercial dressings cannot. PMID:26888442

  8. Effect of Fluid Flow on Zinc Electrodeposits from Acid Chloride Electrolytes. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Abdelmassir, A. A.

    1982-01-01

    Zinc was deposited potentiostatically from acid chloride baths. Once bath chemistry and electrochemistry were controlled, the study was focused on convective mass transfer at horizontal electrodes and its effect on cell performance. A laser schlieren imaging technique allowed in situ observations of flow patterns and their correlation with current transients. Convection was turbulent and mass transfer as a function of Rayleigh number was well correlated by: Sh = 0.14 R to the 1/3 power. Similarly, convection initiation time was correlated by DT/d squared = 38 Ra to the -2/3 power. Time scale of fluctuations was about half the initiation time. Taking the boundary layer thickness as a characteristic length, a critical Rayleigh number for the onset of convection was deduced: Ra sub CR = 5000. Placing the anode on the top of the cathode completely changed the flow pattern but kept the I-t curves identical whereas the use of a cathode grid doubled the limiting current. A well defined plateau in the current voltage curves suggested that hydrogen evolution has been successfully inhibited. Finally, long time deposition showed that convection at horizontal electrodes increased the induction time for dentrite growth by at least a factor of 2 with respect to a vertical wire.

  9. Thermodynamics of aqueous borate solutions I. Mixture of boric acid with sodium or potassium borate and chloride

    SciTech Connect

    Simonson, J.M.; Roy, R.N.; Roy, L.N.; Johnson, D.A.

    1987-10-01

    Potentials for the cell without liquid junction H/sub 2/, Ptlt. slashB(OH)/sub 3/(m/sub 1/),MB(OH)/sub 4/(m/sub 2/),MCl(m/sub 3/)lt. slashAgCl,Ag where M is sodium or potassium are reported over a range of ionic strength to I = 3 mol-kg/sup -1/ at 5 to 55/sup 0/C. Total boron concentration in the solutions was restricted to low levels to minimize formation of polynuclear boron species. Cell potentials are treated with the Pitzer ion interaction treatment for mixed electrolytes, with linear ionic strength dependence assumed for the activity coefficient of undissociated boric acid. Trace activity coefficients of sodium and potassium borates in chloride media are calculated at various temperatures.

  10. Synthesis of Pd9Ru@Pt nanoparticles for oxygen reduction reaction in acidic electrolytes

    NASA Astrophysics Data System (ADS)

    Sun, Yu; Hsieh, Yu-Chi; Chang, Li-Chung; Wu, Pu-Wei; Lee, Jyh-Fu

    2015-03-01

    Nanoparticles of PdRu, Pd3Ru, and Pd9Ru are synthesized and impregnated on carbon black via a wet chemical reflux process. X-ray diffraction patterns of the as-synthesized samples, PdxRu/C (x = 1/3/9), suggest successful formation of alloy without presence of individual Pd and Ru nanoparticles. Images from transmission electron microscope confirm irregularly-shaped nanoparticles with average size below 3 nm. Analysis from extended X-ray absorption fine structure on both Pd and Ru K-edge absorption profiles indicate the Ru atoms are enriched on the surface of PdxRu/C. Among these samples, the Pd9Ru/C exhibits the strongest electrocatalytic activity for oxygen reduction reaction (ORR) in an oxygen-saturated 0.1 M aqueous HClO4 solution. Subsequently, the Pd9Ru/C undergoes Cu under potential deposition, followed by a galvanic displacement reaction to deposit a Pt monolayer on the Pd9Ru surface (Pd9Ru@Pt). The Pd9Ru@Pt reveals better ORR performance than that of Pt, reaching a mass activity of 0.38 mA μg-1Pt, as compared to that of commercially available Pt nanoparticles (0.107 mA μg-1Pt). The mechanisms responsible for the ORR enhancement are attributed to the combined effects of lattice strain and ligand interaction. In addition, this core-shell Pd9Ru@Pt electrocatalyst represents a substantial reduction in the amount of Pt consumption and raw material cost.

  11. Synthesis of Pd9Ru@Pt nanoparticles for oxygen reduction reaction in acidic electrolytes

    DOE PAGESBeta

    Sun, Yu; Hsieh, Yu -Chi; Chang, Li -Chung; Wu, Pu -Wei; Lee, Jyh -Fu

    2014-11-22

    Nanoparticles of PdRu, Pd₃Ru, and Pd₉Ru are synthesized and impregnated on carbon black via a wet chemical reflux process. X-ray diffraction patterns of the as-synthesized samples, PdxRu/C (x=1/3/9), suggest succesful formation of alloy without presence of individual Pd and Ru nanoparticles. Images from transmission electron microscope confirm irregularly-shaped nanoparticles with average size below 3 nm. Analysis from extended X-ray absorption fine structure on both Pd and Ru K-edge absorption profiles indicate the Ru atoms are enriched on the surface of PdxRu/C. Among these samples, the Pd₉Ru/C exhibits the strongest electrocatalytic activity for oxygen reduction reaction (ORR) in an oxygen-saturated 0.1more » M aqueous HClO₄ solution. Subsequently, the Pd₉Ru/C undegoes Cu under potential deposition, followed by a galvanic displacement reaction to deposit a Pt monolayer on the Pd₉Ru surface (Pd₉Ru@Pt). The Pd₉Ru@Pt reveals better ORR performance than that of Pt, reaching a mass activity of 0.38 mA μg⁻¹ Pt, as compared to that of commercially available Pt nanoparticles (0.107 mA μg⁻¹ Pt). Thus, the mechanisms responsible for the ORR enhancement are attributed to the combined effects of lattice strain and ligand interaction. In addition, this core-shell Pd₉Ru@Pt electrocatalyst represents a substantial reduction in the amount of Pt consumption and raw material cost.« less

  12. Nanoparticles of Ag with a Pt and Pd rich surface supported on carbon as a new catalyst for the oxygen electroreduction reaction (ORR) in acid electrolytes: Part 1

    NASA Astrophysics Data System (ADS)

    Pech-Pech, I. E.; Gervasio, Dominic F.; Godínez-Garcia, A.; Solorza-Feria, O.; Pérez-Robles, J. F.

    2015-02-01

    Silver (Ag) nanoparticles enriched with platinum (Pt) and palladium (Pd) on their surfaces (Ag@Pt0.1Pd0.1) are supported on Vulcan XC-72 carbon (C) to form a new catalyst (Ag@Pt0.1Pd0.1/C) for the oxygen reduction reaction (ORR) in acid electrolytes. This catalyst is prepared in one pot by reducing Ag and then Pt and Pd metal salts with sodium borohydride in the presence of trisodium citrate then adding XC-72 while applying intense ultrasound. The metallic Ag@Pt0.1Pd0.1 nanoparticles contain 2 weight percent of Pt, are spherical and have an average size less than 10 nm as determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). At the ORR potentials, Ag nanoparticles on carbon (Ag/C) rapidly lose Ag by dissolution and show no more catalytic activity for the ORR than the carbon support, whereas Ag@Pt0.1Pd0.1/C is a stable catalyst and exhibits 1.4 and 1.6 fold greater specific activity, also 3.6 and 2.8 fold greater mass activity for ORR in 0.5 M H2SO4 solution than comparable Pt/C and Pt0.5Pd0.5/C catalysts with the same Pt loading as determined for thin-films of these catalysts on a rotating-disk electrode (TF-RDE). Using silver nanoparticles increases Pt utilization and therefore decreases Pt-loading and cost of a catalyst for a proton exchange membrane fuel cell (PEMFC) electrode.

  13. Background electrolytes in 50% methanol/water for the determination of acidity constants of basic drugs by capillary zone electrophoresis.

    PubMed

    de Nogales, Vasco; Ruiz, Rebeca; Rosés, Martí; Ràfols, Clara; Bosch, Elisabeth

    2006-08-01

    The acidic dissociation constants of several hydrophobic drugs, amiodarone and a series of antidepressants that show a secondary or tertiary amino group, were determined in a 50% methanol/water mixture by capillary zone electrophoresis. The electrophoretic behavior of buffers prepared from sodium acetate, tris(hydroxymethyl) aminomethane hydrochloride, sodium hydrogenphosphate, ammonium chloride, ethanolamine, butilammonium chloride, and sodium borate in the hydroalcoholic solution was tested. Thus, all of them follow the Ohm's law until about 25 kV and, therefore, they can be used without significant Joule heat dissipation at 20 kV. For the studied drugs, buffers prepared with phosphate or borate give effective mobility measurements lower than those from other buffers. The wide pKa range of the studied drugs provides a wide pH range where the protonated forms of the amino compounds coexist with hydrogenphosphate ions and where the neutral amines coexist with boric acid. The decrease of the experimental effective mobilities in these instances can be explained through the interactions between coexisting species. Therefore, phosphate and borate buffers should be avoided to determine the mobility of amines with aqueous pKa higher than 8, at least in solutions with high methanol content. Independent measurements of acidic dissociation constants of drugs validate this statement. PMID:16723130

  14. Effects of acid-etching solutions on human enamel and dentin.

    PubMed

    Fanchi, M; Breschi, L

    1995-06-01

    Nine noncarious human molars were extracted and stored in saline solution. Three standard occlusal cavities with beveled enamel margins were prepared on each tooth and etched with the etching solutions of three dentinal adhesive systems: (1) 37% phosphoric acid solution, (2) 4.3% oxalic acid and 2.6% aluminum salts solution, and (3) 10% maleic acid solution. Scanning electron microscopic analysis revealed that all the etching solutions affected the enamel surface morphology. The solution of oxalic acid and aluminum salts removed primarily the prism core material and partially the periphery of the prisms, but did not affect the nonbeveled enamel surface. Phosphoric and maleic acids removed both prism core materials and prism periphery; these specimens also showed areas in which no prism morphology could be detected. These two acids also removed apatite crystals from the prism core of the intact enamel surface. PMID:8602425

  15. Ion-Sensitive Characteristics of an Electrolyte-Solution-Gate ZnO/ZnMgO Heterojunction Field-Effect Transistor as a Biosensing Transducer

    NASA Astrophysics Data System (ADS)

    Koike, Kazuto; Takagi, Daisuke; Kawasaki, Motoki; Hashimoto, Takahito; Inoue, Tomoyuki; Ogata, Ken-ichi; Sasa, Shigehiko; Inoue, Masataka; Yano, Mitsuaki

    2007-10-01

    Characteristics of an ion-sensitive ZnO/ZnMgO heterojunction field-effect transistor (HFET) with an amine-modified single-crystalline O-polar ZnMgO gate electrode are discussed to develop the application to biosensing transducers. The ion-sensitivity was based on the proton transfer to/from the amino groups on the gate electrode, the amine-modification of which was performed using a silanization technique by immersing the HFET into an aminosilane based solution. Stable operation in electrolyte solution in accordance with the standard FET theory with small hysteresis and small leakage current was confirmed, and the amperometric operation revealed a high pH sensitivity of -20 μA/pH with a reproducible result. A potential application of the ion-sensitive HFET to amperometric biosensing transducers was also demonstrated by immobilizing enzyme molecules of glucose oxidase on the amine-modified gate electrode.

  16. Dependence of the frequency dispersion of the bulk viscosity coefficient of solutions of electrolytes on the nature of the decay of relaxing fluxes

    NASA Astrophysics Data System (ADS)

    Odinaev, S.; Akdodov, D. M.

    2016-06-01

    The region of the frequency dispersion of the bulk viscosity coefficient η V (ω) of solutions of electrolytes is studied as a function of the nature of the decay of the stress tensor in the momentum and configuration space, the analytical expressions of which are derived by means of kinetic equations. Numerical calculations of η V (ω) for a water solution of NaCl are performed over a wide range of frequencies, temperatures, and densities using a selection of the potentials of intermolecular interaction Φ{in{itab}}(|ěc r|) and radial distribution function {itg}{in{itab}}(|ěc r|). It is shown that the region of frequency dispersion η V (ω) based on the power law of the decay of the stress tensor is wide ( 105 Hz), while the region based on the exponential law is narrow ( 102 Hz).

  17. Interaction of trace elements in acid mine drainage solution with humic acid.

    PubMed

    Suteerapataranon, Siripat; Bouby, Muriel; Geckeis, Horst; Fanghänel, Thomas; Grudpan, Kate

    2006-06-01

    The release of metal ions from a coal mining tailing area, Lamphun, Northern Thailand, is studied by leaching tests. Considerable amounts of Mn, Fe, Al, Ni and Co are dissolved in both simulated rain water (pH 4) and 10 mg L(-1) humic acid (HA) solution (Aldrich humic acid, pH 7). Due to the presence of oxidizing pyrite and sulfide minerals, the pH in both leachates decreases down to approximately 3 combined with high sulfate concentrations typical to acid mine drainage (AMD) water composition. Interaction of the acidic leachates upon mixing with ground- and surface water containing natural organic matter is simulated by subsequent dilution (1:100; 1:200; 1:300; 1:500) with a 10 mg L(-1) HA solution (ionic strength: 10(-3) mol L(-1)). Combining asymmetric flow field-flow fractionation (AsFlFFF) with UV/Vis and ICP-MS detection allows for the investigation of metal ion interaction with HA colloid and colloid size evolution. Formation of colloid aggregates is observed by filtration and AsFlFFF depending on the degree of the dilution. While the average HA size is initially found to be 2 nm, metal-HA complexes are always found to be larger. Such observation is attributed to a metal induced HA agglomeration, which is found even at low coverage of HA functional groups with metal ions. Increasing the metal ion to HA ratio, the HA bound metal ions and the HA entities are growing in size from <3 to >450 nm. At high metal ion to HA ratios, precipitation of FeOOH phases and HA agglomeration due to colloid charge neutralization by complete saturation of HA complexing sites are responsible for the fact that most of Fe and Al precipitate and are found in a size fraction >450 nm. In the more diluted solutions, HA is more relevant as a carrier for metal ion mobilization. PMID:16631855

  18. Direct Electric Current Treatment under Physiologic Saline Conditions Kills Staphylococcus epidermidis Biofilms via Electrolytic Generation of Hypochlorous Acid

    PubMed Central

    Sandvik, Elizabeth L.; McLeod, Bruce R.; Parker, Albert E.; Stewart, Philip S.

    2013-01-01

    The purpose of this study was to investigate the mechanism by which a direct electrical current reduced the viability of Staphylococcus epidermidis biofilms in conjunction with ciprofloxacin at physiologic saline conditions meant to approximate those in an infected artificial joint. Biofilms grown in CDC biofilm reactors were exposed to current for 24 hours in 1/10th strength tryptic soy broth containing 9 g/L total NaCl. Dose-dependent log reductions up to 6.7 log10 CFU/cm2 were observed with the application of direct current at all four levels (0.7 to 1.8 mA/cm2) both in the presence and absence of ciprofloxacin. There were no significant differences in log reductions for wells with ciprofloxacin compared to those without at the same current levels. When current exposures were repeated without biofilm or organics in the medium, significant generation of free chlorine was measured. Free chlorine doses equivalent to the 24 hour endpoint concentration for each current level were shown to mimic killing achieved by current application. Current exposure (1.8 mA/cm2) in medium lacking chloride and amended with sulfate, nitrate, or phosphate as alternative electrolytes produced diminished kills of 3, 2, and 0 log reduction, respectively. Direct current also killed Pseudomonas aeruginosa biofilms when NaCl was present. Together these results indicate that electrolysis reactions generating hypochlorous acid from chloride are likely a main contributor to the efficacy of direct current application. A physiologically relevant NaCl concentration is thus a critical parameter in experimental design if direct current is to be investigated for in vivo medical applications. PMID:23390518

  19. Direct electric current treatment under physiologic saline conditions kills Staphylococcus epidermidis biofilms via electrolytic generation of hypochlorous acid.

    PubMed

    Sandvik, Elizabeth L; McLeod, Bruce R; Parker, Albert E; Stewart, Philip S

    2013-01-01

    The purpose of this study was to investigate the mechanism by which a direct electrical current reduced the viability of Staphylococcus epidermidis biofilms in conjunction with ciprofloxacin at physiologic saline conditions meant to approximate those in an infected artificial joint. Biofilms grown in CDC biofilm reactors were exposed to current for 24 hours in 1/10(th) strength tryptic soy broth containing 9 g/L total NaCl. Dose-dependent log reductions up to 6.7 log(10) CFU/cm(2) were observed with the application of direct current at all four levels (0.7 to 1.8 mA/cm(2)) both in the presence and absence of ciprofloxacin. There were no significant differences in log reductions for wells with ciprofloxacin compared to those without at the same current levels. When current exposures were repeated without biofilm or organics in the medium, significant generation of free chlorine was measured. Free chlorine doses equivalent to the 24 hour endpoint concentration for each current level were shown to mimic killing achieved by current application. Current exposure (1.8 mA/cm(2)) in medium lacking chloride and amended with sulfate, nitrate, or phosphate as alternative electrolytes produced diminished kills of 3, 2, and 0 log reduction, respectively. Direct current also killed Pseudomonas aeruginosa biofilms when NaCl was present. Together these results indicate that electrolysis reactions generating hypochlorous acid from chloride are likely a main contributor to the efficacy of direct current application. A physiologically relevant NaCl concentration is thus a critical parameter in experimental design if direct current is to be investigated for in vivo medical applications. PMID:23390518

  20. Observation of pH Value in Electrokinetic Remediation using various electrolyte (MgSO4, KH2PO4 and Na(NO3)) for Barren Acidic Soil at Ayer Hitam, Johor, Malaysia

    NASA Astrophysics Data System (ADS)

    Norashira, J.; Zaidi, E.; Aziman, M.; Saiful Azhar, A. T.

    2016-07-01

    Barren acidic soil collected at Ayer Hitam, Johor Malaysia was recorded at pH value of 2.36 with relative humidity of 86%. This pH value is not suitable for the growth of any plants especially for the soil stabilization purposes. Gradation weathering within the range of 4 to 6 indicates an incomplete/partial weathering process. The soil grade in this range is known as a black shale mudstone. Beside, this also influences to a factor of the high surface water runoff at this particular soil species. As the acidic pH become a major problem for soil fertilizing hence an appropriate technique was implemented known as using ‘Electrokinetic Remediation’, EKR. This technique has a great potential in changing the soil pH value from acidic to less acidic and also kept maintain the pH at the saturated rate of electrochemical process. This research study presents the monitoring data of pH value due to the effect of various electrolyte consist of 0.5M of MgSO4, KH2PO4, and Na(NO3). Here, the distilled water (DW) was used as reference solution. The electric field was provided by dipping two pieces of identical rectangular aluminum foil as anode and cathode. The EKR was conducted under a constant voltage gradient of 50 V/m across the sample bulk at 0.14 m length measured between both electrodes. The data collection was conducted during the total period of 7 days surveillance. The variation of pH values at the remediation area between anode and cathode for various type of electrolyte indicates that there are a significant saturated value as it reaches 7 days of treatment. During the analysis, it is found that the highest pH value at the remediation area after 7 days treatment using Na(NO3), KH2PO4 and MgSO4 was 3.93, 3.33 and 3.39 respectively. Hence from the last stage of pH value observation, it can be conclude that the best electrolyte for barren soil treatment is Na(NO3) whereby it contribute to highest pH value and turn the soil to be less acidic.

  1. Comparison of peak shape in hydrophilic interaction chromatography using acidic salt buffers and simple acid solutions.

    PubMed

    Heaton, James C; Russell, Joseph J; Underwood, Tim; Boughtflower, Robert; McCalley, David V

    2014-06-20

    The retention and peak shape of neutral, basic and acidic solutes was studied on hydrophilic interaction chromatography (HILIC) stationary phases that showed both strong and weak ionic retention characteristics, using aqueous-acetonitrile mobile phases containing either formic acid (FA), ammonium formate (AF) or phosphoric acid (PA). The effect of organic solvent concentration on the results was also studied. Peak shape was good for neutrals under most mobile phase conditions. However, peak shapes for ionised solutes, particularly for basic compounds, were considerably worse in FA than AF. Even neutral compounds showed deterioration in performance with FA when the mobile phase water concentration was reduced. The poor performance in FA cannot be entirely attributed to the negative impact of ionic retention on ionised silanols on the underlying silica base materials, as results using PA at lower pH (where their ionisation is suppressed) were inferior to those in AF. Besides the moderating influence of the salt cation on ionic retention, it is likely that salt buffers improve peak shape due to the increased ionic strength of the mobile phase and its impact on the formation of the water layer on the column surface. PMID:24813934

  2. Release of nitrous acid and nitrogen dioxide from nitrate photolysis in acidic aqueous solutions.

    PubMed

    Scharko, Nicole K; Berke, Andrew E; Raff, Jonathan D

    2014-10-21

    Nitrate (NO3(-)) is an abundant component of aerosols, boundary layer surface films, and surface water. Photolysis of NO3(-) leads to NO2 and HONO, both of which play important roles in tropospheric ozone and OH production. Field and laboratory studies suggest that NO3¯ photochemistry is a more important source of HONO than once thought, although a mechanistic understanding of the variables controlling this process is lacking. We present results of cavity-enhanced absorption spectroscopy measurements of NO2 and HONO emitted during photodegradation of aqueous NO3(-) under acidic conditions. Nitrous acid is formed in higher quantities at pH 2-4 than expected based on consideration of primary photochemical channels alone. Both experimental and modeled results indicate that the additional HONO is not due to enhanced NO3(-) absorption cross sections or effective quantum yields, but rather to secondary reactions of NO2 in solution. We find that NO2 is more efficiently hydrolyzed in solution when it is generated in situ during NO3(-) photolysis than for the heterogeneous system where mass transfer of gaseous NO2 into bulk solution is prohibitively slow. The presence of nonchromophoric OH scavengers that are naturally present in the environment increases HONO production 4-fold, and therefore play an important role in enhancing daytime HONO formation from NO3(-) photochemistry. PMID:25271384

  3. Electrolytic oxidation of anthracite

    USGS Publications Warehouse

    Senftle, F.E.; Patton, K.M.; Heard, I., Jr.

    1981-01-01

    An anthracite slurry can be oxidized only with difficulty by electrolytic methods in which aqueous electrolytes are used if the slurry is confined to the region of the anode by a porous pot or diaphragm. However, it can be easily oxidized if the anthracite itself is used as the anode. No porous pot or diaphragm is needed. Oxidative consumption of the coal to alkali-soluble compounds is found to proceed preferentially at the edges of the aromatic planes. An oxidation model is proposed in which the chief oxidants are molecular and radical species formed by the electrolytic decomposition of water at the coal surface-electrolyte interface. The oxidation reactions proposed account for the opening of the aromatic rings and the subsequent formation of carboxylic acids. The model also explains the observed anisotropic oxidation and the need for the porous pot or diaphragm used in previous studies of the oxidation of coal slurries. ?? 1981.

  4. Planetary Bioresources and Astroecology. 1. Planetary Microcosm Bioassays of Martian and Carbonaceous Chondrite Materials: Nutrients, Electrolyte Solutions, and Algal and Plant Responses

    NASA Astrophysics Data System (ADS)

    Mautner, Michael N.

    2002-07-01

    The biological fertilities of planetary materials can be assessed using microcosms based on meteorites. This study applies microcosm tests to martian meteorites and analogues and to carbonaceous chondrites. The biological fertilities of these materials are rated based on the soluble electrolyte nutrients, the growth of mesophile and cold-tolerant algae, and plant tissue cultures. The results show that the meteorites, in particular the Murchison CM2 carbonaceous chondrite and DaG 476 martian shergottite, contain high levels of water-extractable Ca, Mg, and SO 4-S. The martian meteorites DaG 476 and EETA 79001 also contain higher levels of extractable essential nutrients NO 3-N (0.013-0.017 g kg -1) and PO 4-P (0.019-0.046 g kg -1) than the terrestrial analogues. The yields of most of the water-extractable electrolytes vary only by factors of 2-3 under a wide range of planetary conditions. However, the long-term extractable phosphate increases significantly under a CO 2 atmosphere. The biological yields of algae and plant tissue cultures correlate with extractable NO 3-N and PO 4-P, identifying these as the limiting nutrients. Mesophilic algae and Asparagus officinalis cultures are identified as useful bioassay agents. A fertility rating system based on microcosm tests is proposed. The results rate the fertilities in the order martian basalts > terrestrial basalt, agricultural soil > carbonaceous chondrites, lava ash > cumulate igneous rock. The results demonstrate the application of planetary microcosms in experimental astroecology to rate planetary materials as targets for astrobiology exploration and as potential space bioresources. For example, the extractable materials in Murchison suggest that concentrated internal solutions in carbonaceous asteroids (3.8 mol L -1 electrolytes and 10 g L -1 organics) can support and disperse microorganisms introduced by natural or directed panspermia in early solar systems. The results also suggest that carbonaceous asteroids

  5. Compatible solute influence on nucleic acids: Many questions but few answers

    PubMed Central

    Kurz, Matthias

    2008-01-01

    Compatible solutes are small organic osmolytes including but not limited to sugars, polyols, amino acids, and their derivatives. They are compatible with cell metabolism even at molar concentrations. A variety of organisms synthesize or take up compatible solutes for adaptation to extreme environments. In addition to their protective action on whole cells, compatible solutes display significant effects on biomolecules in vitro. These include stabilization of native protein and nucleic acid structures. They are used as additives in polymerase chain reactions to increase product yield and specificity, but also in other nucleic acid and protein applications. Interactions of compatible solutes with nucleic acids and protein-nucleic acid complexes are much less understood than the corresponding interactions of compatible solutes with proteins. Although we may begin to understand solute/nucleic acid interactions there are only few answers to the many questions we have. I summarize here the current state of knowledge and discuss possible molecular mechanisms and thermodynamics. PMID:18522725

  6. Electrolytic cell

    NASA Astrophysics Data System (ADS)

    Bullock, J. S.; Hale, B. D.

    1984-09-01

    An apparatus is described for the separation of the anolyte and the catholyte during electrolysis. The electrolyte flows through an electrolytic cell between the oppositely charged electrodes. The cell is equipped with a wedge-shaped device, the tapered end is located between the electrodes on the effluent side of the cell. The wedge diverts the flow of the electrolyte to either side of the wedge, substantially separating the anolyte and the catholyte.

  7. Thermodynamic studies of ionic hydration and interactions for amino acid ionic liquids in aqueous solutions at 298.15 K.

    PubMed

    Dagade, Dilip H; Madkar, Kavita R; Shinde, Sandeep P; Barge, Seema S

    2013-01-31

    Amino acid ionic liquids are a special class of ionic liquids due to their unique acid-base behavior, biological significance, and applications in different fields such as templates in synthetic chemistry, stabilizers for biological macromolecules, etc. The physicochemical properties of these ionic liquids can easily be altered by making the different combinations of amino acids as anion along with possible cation modification which makes amino acid ionic liquids more suitable to understand the different kinds of molecular and ionic interactions with sufficient depth so that they can provide fruitful information for a molecular level understanding of more complicated biological processes. In this context, volumetric and osmotic coefficient measurements for aqueous solutions containing 1-ethyl-3-methylimidazolium ([Emim]) based amino acid ionic liquids of glycine, alanine, valine, leucine, and isoleucine are reported at 298.15 K. From experimental osmotic coefficient data, mean molal activity coefficients of ionic liquids were estimated and analyzed using the Debye-Hückel and Pitzer models. The hydration numbers of ionic liquids in aqueous solutions were obtained using activity data. Pitzer ion interaction parameters are estimated and compared with other electrolytes reported in the literature. The nonelectrolyte contribution to the aqueous solutions containing ionic liquids was studied by calculating the osmotic second virial coefficient through an application of the McMillan-Mayer theory of solution. It has been found that the second osmotic virial coefficient which includes volume effects correlates linearly with the Pitzer ion interaction parameter estimated independently from osmotic data as well as the hydrophobicity of ionic liquids. The enthalpy-entropy compensation effect, explained using the Starikov-Nordén model of enthalpy-entropy compensation, and partial molar entropy analysis for aqueous [Emim][Gly] solutions are made by using experimental Gibb

  8. Effect of potassium sodium tartrate and sodium citrate on the preparation of {alpha}-calcium sulfate hemihydrate from flue gas desulfurization gypsum in a concentrated electrolyte solution

    SciTech Connect

    Shen, Z.X.; Guan, B.H.; Fu, H.L.; Yang, L.C.

    2009-12-15

    Flue gas desulfurization (FGD) gypsum mainly composed of calcium sulfate dihydrate (DH) was used as a raw material to obtain alpha-calcium sulfate hemihydrate ({alpha}-HH) through dehydration in a Ca-Mg-K-Cl-solution medium at 95{sup o}C under atmospheric pressure. The effects of potassium sodium tartrate and sodium citrate on the preparation of alpha-HH in the electrolyte solution were investigated. The results revealed that the addition of potassium sodium tartrate (1.0 x 10{sup -2} - 2.5 x 10{sup -2}M) decreased the dehydration rate of FGD gypsum and increased the length/width (l/w) ratio of {alpha}-HH crystals, which could yield unfavorable strength properties. Addition of sodium citrate (1.0 x 10{sup -5} - 2.0 x 10{sup -5}M) slightly increased the dehydration rate of FGD gypsum and decreased the l/w ratio of {alpha}-HH crystals, which could be beneficial to increase strength. However, it also led to a partial formation of anhydrite (AH) crystals. AH was also the only dehydration product when the concentration of sodium citrate increased to 1.0 x 10{sup -4}M. Therefore, sodium citrate rather than potassium sodium tartrate could be used as an additive in Ca-Mg-K-Cl electrolyte solutions if alpha-HH with a shorter l/w ratio is the desired product from FGD gypsum dehydration. The concentration of sodium citrate should be properly controlled to reduce the formation of AH.

  9. Resistance to protein and oil fouling of sulfobetaine-grafted Poly(vinylidene Fluoride) hollow fiber membrane and the electrolyte-responsive behavior in NaCl solution

    NASA Astrophysics Data System (ADS)

    Li, Qian; Bi, Qiu-Yan; Liu, Tian-Yin; Wang, Xiao-Lin

    2012-07-01

    An excellent protein-fouling-resistance performance of the sulfobetaine-grafted PVDF hollow fiber membrane was obtained and the potential of sulfobetaine-grafted PVDF membrane to resist the oil fouling was confirmed in the filtration solution which contained inorganic electrolyte, sodium chloride (NaCl). The electrolyte-responsive behavior of the sulfobetaine-modified PVDF membrane was demonstrated by the filtration of NaCl aqueous solution. The grafting amount of the modified PVDF hollow fiber membrane showed a stable value as 680 μg/cm2. An almost complete coverage of the membrane surface by the grafted sulfobetaine polymer contributed to the high hydrophilicity and membrane strength. The membrane surface became denser and the permeate flux reduced with the increase of NaCl concentration. The cyclic filtration experiment showed that during the filtration of the protein solution with 0.05 mol/L of NaCl, the sulfobetaine-grafted PVDF membrane exhibited an excellent protein-fouling-resistance performance with a high relative flux recovery of 98.2% and a low irreversible fouling extent which was lower 10 times than that of the nascent PVDF hollow fiber membrane. In addition, the sulfobetaine-grafted PVDF hollow fiber membrane showed an oil-fouling-resistance property during the filtration experiment of the oil-in-water emulsion with 0.05 mol/L of NaCl, resulting in an relative flux recovery of about twice that of the nascent PVDF membrane. The results extended the application of poly(sulfobetaine)-g-PVDF hollow fiber membrane in the fields of bio-separation, artificial oil and wastewater treatment.

  10. EXAFS Study on the Reactions Between Iron And Fulvic Acid in Acid Aqueous Solutions

    SciTech Connect

    Schaik, J.W.J.van; Persson, I.; Kleja, D.B.; Gustafsson, J.P.

    2009-05-26

    Iron(III) competes with trace metals for binding sites on organic ligands. We used X-ray absorption fine structure (EXAFS) spectroscopy to determine the binding mode and oxidation state of iron in solutions initially containing only iron(III) and fulvic acid at pHs 2 and 4. EXAFS spectra were recorded at different times after sample preparation. Iron was octahedrally configured with inner-sphere Fe-O interactions at 1.98-2.10 {angstrom}, depending on the oxidation state of iron. Iron(III) formed complexes with fulvic acid within 15 min. Iron(III) was reduced to iron(II) with time at pH 2, whereas no significant reduction occurred at pH 4. No signs of dimeric/trimeric hydrolysis products were found in any of the solution samples (<0.45 {mu}m). However, the isolated precipitate of the pH 2 sample (>0.45 {mu}m) showed Fe{hor_ellipsis}Fe distances, indicating the presence of tightly packed iron(III) trimers and/or clusters of corner-sharing octahedra. It is suggested that the binding mode of iron(III) to fulvic acid at low pH may be phase-dependent: in solution mononuclear complexes predominate, whereas in the solid phase hydrolyzed polynuclear iron(III) complexes form, even at very low pH values. The observed pH dependence of iron(III) reduction was consistent with expected results based on thermodynamic calculations for model ligands.

  11. Large-scale production of anhydrous nitric acid and nitric acid solutions of dinitrogen pentoxide

    DOEpatents

    Harrar, Jackson E.; Quong, Roland; Rigdon, Lester P.; McGuire, Raymond R.

    2001-01-01

    A method and apparatus are disclosed for a large scale, electrochemical production of anhydrous nitric acid and N.sub.2 O.sub.5. The method includes oxidizing a solution of N.sub.2 O.sub.4 /aqueous-HNO.sub.3 at the anode, while reducing aqueous HNO.sub.3 at the cathode, in a flow electrolyzer constructed of special materials. N.sub.2 O.sub.4 is produced at the cathode and may be separated and recycled as a feedstock for use in the anolyte. The process is controlled by regulating the electrolysis current until the desired products are obtained. The chemical compositions of the anolyte and catholyte are monitored by measurement of the solution density and the concentrations of N.sub.2 O.sub.4.

  12. Uptake of Hypobromous Acid (HOBr) by Aqueous Sulfuric Acid Solutions: Low-Temperature Solubility and Reaction

    NASA Technical Reports Server (NTRS)

    Iraci, Laura T.; Michelsen, Rebecca R.; Ashbourn, Samatha F. M.; Rammer, Thomas A.; Golden, David M.

    2005-01-01

    Hypobromous acid (HOBr) is a key species linking inorganic bromine to the chlorine and odd hydrogen chemical families. We have measured the solubility of HOBr in 45 - 70 wt% sulfuric acid solutions representative of upper tropospheric and lower stratospheric aerosol composition. Over the temperature range 201 - 252 K, HOBr is quite soluble in sulfuric acid, with an effective Henry's law coefficient, H* = 10(exp 4) - 10(exp 7) mol/L/atm. H* is inversely dependent on temperature, with Delta H = -46.2 kJ/mol and Delta S = -106.2 J/mol/K for 55 - 70 wt% H2SO4 solutions. Our study includes temperatures which overlap both previous measurements of HOBr solubility. For uptake into aqueous 45 wt% H2SO4, the solubility can be described by log H* = 3665/T - 10.63. For 55 - 70 wt% H2SO4, log H* = 2412/T - 5.55. At temperatures colder than approx. 213 K, the solubility of HOBr in 45 wt% H2SO4 is noticeably larger than in 70 wt% H2SO4. The solubility of HOBr is comparable to that of HBr, indicating that upper tropospheric and lower stratospheric aerosols should contain equilibrium concentrations of HOBr which equal or exceed those of HBr. Our measurements indicate chemical reaction of HOBr upon uptake into aqueous sulfuric acid in the presence of other brominated gases followed by evolution of gaseous products including Br2O and Br2, particularly at 70 wt% H2SO4.

  13. Electro-Convective and Non-Equilibrium Electro-Osmotic Instability of Electric Conduction from an Electrolyte Solution into a Charge Selective Solid

    NASA Astrophysics Data System (ADS)

    Rubinstein, Isaak

    2006-03-01

    Electro-convection is reviewed as a mechanism of mixing in the diffusion layer of a strong electrolyte adjacent to a charge-selective solid, such as an ion exchange (electrodialysis) membrane or an electrode. Two types of electro-convection in strong electrolytes may be distinguished: bulk electro-convection , due to the action of the electric field upon the residual space charge of a quasi-electro-neutral bulk solution, and convection induced by electro-osmotic slip, due to electric forces acting in the thin electric double layer of either quasi-equilibrium or non-equilibrium type near the solid/liquid interface. According to recent studies, the latter appears to be the likely source of mixing in the diffusion layer, leading to `over-limiting' conductance in electrodialysis. Electro-convection near a uniform charge selective solid/liquid interface sets on as a result of hydrodynamic instability of one-dimensional steady state electric conduction through such an interface. We discuss instabilities of this kind appearing in the full electro-convective and limiting non-equilibrium electro-osmotic formulations. The short- and long-wave aspects of these instabilities are discussed along with the wave-number selection principles and possible sources of low frequency excess electric noise experimentally observed in these systems.

  14. Ionic liquids as electrolytes for non-aqueous solutions electrochemical supercapacitors in a temperature range of 20 °C-80 °C

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Tsay, Ken; Bock, Christina; Zhang, Jiujun

    2016-08-01

    To increase the operating temperature of the supercapacitors (SCs) without compromising their high cycle-life, several typical fluoro- and non-fluoro containing ionic liquids (EMI-mesylate, EMI-hydrogen sulfate, PP13-triflate, PP13-TFSI, and EMI-TFSI, as shown in Fig. 1) are studied as the electrolytes to prepare organic solutions for SC performance measurements using a two-electrode cell. Both cyclic voltammograms and charge/discharge curves at various temperatures such as 20, 40, 60 and 80 °C are collected. At 60 °C, the increased performance order in both rating and cyclability measurements are found to be as follows: 1) EMI-hydrogen sulfate < PP13-TFSI < EMI-mesylate < PP13-triflate < EMI-TFSI for rating; and 2) EMI-hydrogen sulfate < EMI-mesylate < PP13-Triflate < PP13-TFSI < EMI-TFSI for life-time. The fluoro-containing group of ILs, i.e., PP13-Triflate, PP13-TFSI and EMI-TFSI can give a specific capacitance between 100 and 170 F/g for various scan rates for a conventional carbon electrode, and an extended lifetime test of 10, 000 cycles with a capacitance degradation of less than 10%, indicating that these two ion liquids can be used for SC electrolytes operated at high temperature.

  15. EVALUATING EFFECTS OF NEPTUNIUM ON THE SRS METHOD FOR CONTROLLED POTENTIAL COULOMETRIC ASSAY OF PLUTONIUM IN SULFURIC ACID SUPPORTING ELECTROLYTE

    SciTech Connect

    Holland, M; Sheldon Nichols, S

    2008-05-09

    A study of the impact of neptunium on the coulometric assay of plutonium in dilute sulfuric acid was performed. Weight aliquots of plutonium standard solutions were spiked with purified neptunium solution to evaluate plutonium measurement performance for aliquots with Pu:Np ratios of 50:1, 30:1, 20:1, 15:1, and 10:1. Weight aliquots of the pure plutonium standard solution were measured as controls. Routine plutonium instrument control standards were also measured. The presence of neptunium in plutonium aliquots significantly increases the random uncertainty associated with the plutonium coulometric measurement performed in accordance with ISO12183:2005.7 However, the presence of neptunium does not appear to degrade electrode performance and conditioning as aliquots of pure plutonium that were interspersed during the measurement of the mixed Pu:Np aliquots continued to achieve the historical short-term random uncertainty for the method. Lack of adequate control of the neptunium oxidation state is suspected to be the primary cause of the elevated measurement uncertainty and will be pursued in a future study.

  16. Electrocatalysis of fuel cell reactions: Investigation of alternate electrolytes

    NASA Technical Reports Server (NTRS)

    Chin, D. T.; Hsueh, K. L.; Chang, H. H.

    1983-01-01

    Oxygen reduction and transport properties of the electrolyte in the phosphoric acid fuel cell are studied. A theoretical expression for the rotating ring-disk electrode technique; the intermediate reaction rate constants for oxygen reduction on platinum in phosphoric acid electrolyte; oxygen reduction mechanism in trifluoromethanesulfonic acid (TFMSA), considered as an alternate electrolyte for the acid fuel cells; and transport properties of the phosphoric acid electrolyte at high concentrations and temperatures are covered.

  17. High-compactness coating grown by plasma electrolytic oxidation on AZ31 magnesium alloy in the solution of silicate-borax

    NASA Astrophysics Data System (ADS)

    Shen, M. J.; Wang, X. J.; Zhang, M. F.

    2012-10-01

    A ceramic coating was formed on the surface of AZ31 magnesium alloy by plasma electrolytic oxidation (PEO) in the silicate solution with and without borax doped. The composition, morphology, elements and roughness as well as mechanical property of the coating were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and reciprocal-sliding tribometer. The results show that the PEO coating is mainly composed of magnesia. When using borax dope, boron element is permeating into the coating and the boron containing phase exist in the form of amorphous. In addition, the microhardness and compactness of the PEO coating are improved significantly due to doped borax.

  18. Electrochemical properties of LiCoPO4-thin film electrodes in LiF-based electrolyte solution with anion receptors

    NASA Astrophysics Data System (ADS)

    Fukutsuka, Tomokazu; Nakagawa, Takuya; Miyazaki, Kohei; Abe, Takeshi

    2016-02-01

    Compatibility of LiF + anion receptors/propylene carbonate (PC) electrolyte solution with high potential positive electrode for lithium-ion batteries was examined by cyclic voltammetry. As anion receptors, tripropyl borate (TPB), tris(pentafluorophenyl) borane (TPFPB), and tris(hexafluoroisopropyl) borate (THFIPB) were used. LiCoPO4 thin-film electrodes were prepared by sol-gel method and used as both carbon- and binder-free model electrodes. From cyclic voltammograms, LiCoPO4 showed better cycleability in 0.1 mol dm-3 LiF + 0.1 mol dm-3 THFIPB/PC, however, other anion receptors did not give positive influence. It is indicated that the surface protecting layer from F--THFIPB complex and made LiCoPO4 stable. Electrochemical behavior depending on anion receptors was discussed according to reaction activity of F-.

  19. Isothermal heat measurements of TBP-nitric acid solutions

    SciTech Connect

    Smith, J.R.; Cavin, W.S.

    1994-12-16

    Net heats of reaction were measured in an isothermal calorimeter for both single phase (organic) and two phase (organic and aqueous) TBP/HNO{sub 3} reacting solutions at temperatures above 100 C. The oxidation rate constant was determined to be 5.4E-4 min{sup {minus}1} at 110 C for an open ``vented`` system as compared to 1.33 E-3 min{sup {minus}1} in the closed system. The heat released per unit material oxidized was also reduced. The oxidation in both phases was found to be first order in nitric acid and pseudo-zero order in butylnitrate and water. The hydrolysis (esterification) rate constant determined by Nichols` (1.33E-3 min{sup {minus}1}) fit the experimental data from this work well. Forced evaporation of the volatile components by the product gases from oxidation resulted in a cooling mechanism which more than balanced the heat from the oxidation reaction in the two-phased systems. Rate expressions were derived and rate constants determined for both the single and two phase systems. An approximating mathematical model was developed to fit the experimental data and to extrapolate beyond the experimental conditions. This model shows that one foot of ``reacting`` 14.3M HNO{sub 3} aqueous phase solution at 121 C will transport sufficient water to the organic phase to replace evaporative losses, maintaining endothermicity, for organic layers up to 12.2 + 6.0 feet deep. If the pressure in a reacting system is allowed to increase due to insufficient venting the temperature of the organic phase would increase in temperature to reach a new equilibrium. The rate of oxidation would increase not only due to the increase in temperature but also from the increased concentration of dissolved HNO{sub 3} reduction products. Another important factor is that the cooling system described in this work becomes less effective as the total pressure increases. These factors probably contributed to the explosion at Tomsk.

  20. Electrodeposition Behavior of Mn with Ni in Acidic Sulfate Solutions

    NASA Astrophysics Data System (ADS)

    Ji, Dan; Le, Xiawen; Zhong, Qingdong; Zhou, Qiongyu

    2014-09-01

    The influence of Mn2+/Ni2+ mole ratio in electrolytes on the Ni-Mn alloy deposits was studied. The electrodeposition mechanism of Mn with Ni is analyzed by the cyclic voltammogram (CV) and an "induced co-deposition" mechanism is proposed for Ni-Mn alloy electrodeposition. The results show that the Mn content in Ni-Mn alloy deposit and the hardness increased with the increase of Mn2+/Ni2+ mole ratio in electrolytes. When the Mn2+/Ni2+ mole ratio in bath was 2/1, the corrosion current density of the deposit coating was the lowest and the corresponding corrosion potential was higher, and under these conditions the coating with a Mn content of 1.20 wt.% showed good corrosion resistance. The scanning electron microscopy (SEM) of the alloy coatings exhibited that the morphology of Ni-Mn alloy coatings were different from Pure Ni coating, and when Mn2+/Ni2+ was 2/1, the surface was compact and homogeneous.

  1. Calculation of the acid-base equilibrium constants at the alumina/electrolyte interface from the ph dependence of the adsorption of singly charged ions (Na+, Cl-)

    NASA Astrophysics Data System (ADS)

    Gololobova, E. G.; Gorichev, I. G.; Lainer, Yu. A.; Skvortsova, I. V.

    2011-05-01

    A procedure was proposed for the calculation of the acid-base equilibrium constants at an alumina/electrolyte interface from experimental data on the adsorption of singly charged ions (Na+, Cl-) at various pH values. The calculated constants (p K {1/0}= 4.1, p K {2/0}= 11.9, p K {3/0}= 8.3, and p K {4/0}= 7.7) are shown to agree with the values obtained from an experimental pH dependence of the electrokinetic potential and the results of potentiometric titration of Al2O3 suspensions.

  2. The role of electrolyte anions (ClO{sub 4}{sup {minus}}, NO{sub 3}{sup {minus}}, and Cl{sup {minus}}) in divalent metal (M{sup 2+}) adsorption on oxide and hydroxide surfaces in salt solutions

    SciTech Connect

    Criscenti, L.J.; Sverjensky, D.A.

    1999-12-01

    Adsorption of divalent metal ions (M{sup 2+}) onto oxide and hydroxide surfaces from solutions of strong electrolytes has typically been inferred to take place without the involvement of the electrolyte anion. Only in situations where M{sup 2+} forms a strong enough aqueous complex with the electrolyte anion (for example, CdCl{sup +} or PbCl{sup +}) has it been frequently suggested that the metal and the electrolyte anion adsorb simultaneously. A review of experimental data for the adsorption of Cd{sup 2+}, Pb{sup 2+}, Co{sup 2+}, UO{sub 2}{sup 2+}, Zn{sup 2+}, Cu{sup 2+}, Ba{sup 2+}, Sr{sup 2+}, and Ca{sup 2+} onto quartz, silica, goethite, hydrous ferric oxide, corundum, {gamma}-alumina, anatase, birnessite, and magnetite, from NaNO{sub 3}, KNO{sub 3}, NaCl, and NaClO{sub 4} solutions over a wide range of ionic strengths (0.0001 M-1.0 M), reveals that transition and heavy metal adsorption behavior with ionic strength is a function of the type of electrolyte. In NaNO{sub 3} solutions, metal adsorption exhibits little or no dependence on the ionic strength of the solution. However, in NaCl solutions, transition and heavy metal adsorption decreases strongly with increasing ionic strength. In NaClO{sub 4} solutions, metal adsorption decreases strongly with increasing ionic strength. In NaClO{sub 4} solutions, metal adsorption exhibits little dependence on ionic strength but is often suggestive of an increase in metal adsorption with increasing ionic strength. Analysis of selected adsorption edges was carried out using the extended triple-layer model and aqueous speciation models that included metal-nitrate, metal-chloride, and metal-hydroxide complexes.

  3. Studies of the pulse charge of lead-acid batteries for PV applications. Part III. Electrolyte concentration effects on the electrochemical performance of the positive plate

    NASA Astrophysics Data System (ADS)

    Kirchev, A.; Delaille, A.; Karoui, F.; Perrin, M.; Lemaire, E.; Mattera, F.

    2008-05-01

    In the third part of this work the effects of the sulphuric acid concentration on the positive plate discharge capacity, impedance and oxygen overvoltage are discussed. It has been found that the full discharge capacity of the positive plate is available down to electrolyte concentrations of 3 mol l-1 (s.g. 1.18 g ml-1). At further acid dilution, capacity of the positive plate declines, keeping the utilization of the sulphuric acid about 50%. Decreasing the acid concentration, the oxygen overvoltage decreases with a factor of 12-18 mV M-1, excluding the effect of the equilibrium potential of the oxygen electrode as a function of pH. The capacitance of the electrical double layer decrease linearly with the dilution of the sulphuric acid suggesting strong adsorption effects. This suggestion has been confirmed from the measurements of potential of the zero charge of the positive plate, which increases from 1.11 to 1.34 V vs. Ag/Ag2SO4 in the region 1.11-4.60 M H2SO4. From the measurement of the time constant of the electronic transfer through the gel part of the lead dioxide (Tgel) as a function of the acid concentration and the applied potential, a change in the mechanism of the lead dioxide hydration has been estimated-below 1 M H2SO4Tgel increases sharply, showing sharp increases of the extent of the hydration. The dilution of the electrolyte increases substantially the value of average double layer current in the beginning of the charge. During the pulse overcharge at the employed frequency of 1 Hz, the average double layer current is equal to the pulse amplitude, suggesting that the maximal efficiency of the pulse charge is reached.

  4. Acid Solutions for Etching Corrosion-Resistant Metals

    NASA Technical Reports Server (NTRS)

    Simmons, J. R.

    1982-01-01

    New study characterized solutions for etching austenitic stainless steels, nickel-base alloys, and titanium alloys (annealed). Solutions recommended for use remove at least 0.4 mil of metal from surface in less than an hour. Solutions do not cause intergranular attack on metals for which they are effective, when used under specified conditions.

  5. Small angle x-ray scattering of a supercritical electrolyte solution: the effect of density fluctuations on the hydration of ions.

    PubMed

    Testemale, Denis; Coulet, Marie Vanessa; Hazemann, Jean Louis; Simon, Jean Paul; Bley, Françoise; Geaymond, Olivier; Argoud, Roger

    2005-05-15

    Synchrotron small angle x-ray scattering measurements on water and zinc bromide ZnBr2 aqueous solutions were carried out from ambient to supercritical conditions. For both systems several isobars (between 285 and 600 bars) were followed beyond the critical isochore. The data were analyzed through an Ornstein-Zernike formalism in terms of correlation length and null angle structure factor. The results for pure water are in agreement with previously published values. Solutions of different electrolyte concentrations were studied. In each case, the values of the correlation length and null angle structure factor are larger than those of pure water. This effect is more pronounced for higher concentrations and/or for pressure closer to the critical point of pure water. This is in agreement with the shift of the critical point determined in the literature for NaCl solutions. Comparing these results to previous x-ray absorption measurements carried out on identical samples we propose the following two step sequence for ionic hydration up to supercritical conditions: (1) from ambient to about 300 degrees C, an increase of ion pairing and formation of multi-ionic complexes which can be correlated to the decrease of the dielectric constant; (2) an enhancement of the local solvation shell of ions due to the onset of the thermal density fluctuations at high temperature, leading to a screening effect between ions and inhibiting the ion pairing processes. PMID:16161595

  6. Small angle x-ray scattering of a supercritical electrolyte solution: The effect of density fluctuations on the hydration of ions

    NASA Astrophysics Data System (ADS)

    Testemale, Denis; Coulet, Marie Vanessa; Hazemann, Jean Louis; Simon, Jean Paul; Bley, Françoise; Geaymond, Olivier; Argoud, Roger

    2005-05-01

    Synchrotron small angle x-ray scattering measurements on water and zinc bromide ZnBr2 aqueous solutions were carried out from ambient to supercritical conditions. For both systems several isobars (between 285 and 600bars) were followed beyond the critical isochore. The data were analyzed through an Ornstein-Zernike formalism in terms of correlation length and null angle structure factor. The results for pure water are in agreement with previously published values. Solutions of different electrolyte concentrations were studied. In each case, the values of the correlation length and null angle structure factor are larger than those of pure water. This effect is more pronounced for higher concentrations and/or for pressure closer to the critical point of pure water. This is in agreement with the shift of the critical point determined in the literature for NaCl solutions. Comparing these results to previous x-ray absorption measurements carried out on identical samples we propose the following two step sequence for ionic hydration up to supercritical conditions: (1) from ambient to about 300°C, an increase of ion pairing and formation of multi-ionic complexes which can be correlated to the decrease of the dielectric constant; (2) an enhancement of the local solvation shell of ions due to the onset of the thermal density fluctuations at high temperature, leading to a screening effect between ions and inhibiting the ion pairing processes.

  7. Influence of anionic substitution on the electrolyte electroreflectance study of band edge transitions in single crystal Cu2ZnSn(SxSe1-x)4 solid solutions

    NASA Astrophysics Data System (ADS)

    Levcenco, S.; Dumcenco, D.; Wang, Y. P.; Huang, Y. S.; Ho, C. H.; Arushanov, E.; Tezlevan, V.; Tiong, K. K.

    2012-06-01

    Single crystals of Cu2ZnSn(SxSe1-x)4 (CZTSSe) solid solutions were grown by chemical vapor transport technique using iodine trichloride as a transport agent. As confirmed by X-ray investigations, the as-grown CZTSSe solid solutions are single phase and crystallized in kesterite structure. The lattice parameters of CZTSSe were determined and the S contents of the obtained crystals were estimated by Vegard's law. The composition dependent band gaps of CZTSSe solid solutions were studied by electrolyte electroreflectance (EER) measurements at room temperature. From a detailed lineshape fit of the EER spectra, the band gaps of CZTSSe were determined accurately and were found to decrease almost linearly with the increase of Se content, which agreed well with the recent theoretical first-principle calculations by S. Chen, A. Walsh, J.H. Yang, X.G. Gong, L. Sun, P. X. Yang, J.H. Chu, S.H. Wei, Phys. Rev. B 83 (2011) 125201 (5pp).

  8. Dielectric relaxation and underlying dynamics of electrolyte solutions and solvent-molten salt mixtures using terahertz time-domain transmission spectroscopy

    NASA Astrophysics Data System (ADS)

    Asaki, Melanie Lynette Thongs

    Terahertz (THz) transmission spectroscopy is used to obtain the frequency dependent complex dielectric constants of water, methanol, and propylene carbonate, and solutions of lithium salts in these solvents, as well as mixtures of acetonitrile and a room-temperature molten salt. The behavior of the pure solvents is modeled with either two (water and acetonitrile) or three (methanol and propylene carbonate) Debye relaxations. For solutions of lithium salts, the effects of ionic solvation on the relaxation behavior of the solvents is discussed in terms of modifications to the values of the Debye parameters of the pure solvents. In this way we obtain estimates for numbers of irrotationally bound solvent molecules, the numbers of bonds broken or formed, and the effects of ions on the higher frequency relaxations. The same information was obtained for molten salt-acetonitrile systems. In addition, it was determined that at low molten salt concentrations, the mixtures behave like electrolyte solutions of a crystalline salt dissolved in a solvent. At higher molten salt concentrations, the behavior is that of a mixture of two liquids.

  9. Effects of different sulphur amino acids and dietary electrolyte balance levels on performance, jejunal morphology, and immunocompetence of broiler chicks.

    PubMed

    Nikoofard, V; Mahdavi, A H; Samie, A H; Jahanian, E

    2016-02-01

    As alterations of dietary electrolyte balance (DEB) can influence amino acid metabolism via changes the ions incur in their configurations, performance and immunological responses of broiler chicks might be affected. So, the current study was carried out to investigate the effects of different levels of sulphur amino acids (SAA) and DEB on performance, jejunal morphology and immunocompetence of broiler chicks. A total of 360 1-day-old male Ross 308 broiler chicks were randomly assigned to nine experimental treatments with four replicates of 10 birds each. Experimental treatments consisted of three levels of SAA (100, 110, and 120% of NRC recommendation, provided by methionine supplementation in diets with the same cysteine level) and three levels of DEB (150, 250, and 350 mEq/kg) that were fed during the entire of trial in a 3 × 3 factorial arrangement. Results showed that the relative weights of intestine and abdominal fat were decreased markedly (p < 0.001) with increasing levels of SAA and DEB respectively. Antibody titre against sheep red blood cell was neither individually nor in combination influenced by supplementation of SAA or DEB. Nevertheless, a decrease in DEB level led to a suppression in heterophile (p < 0.05) and an increase in lymphocyte counts (p = 0.06); consequently, heterophile to lymphocyte ratio was significantly decreased (p < 0.05) by decremental levels of DEB. Albumin to globulin ratio was increased after inclusion of at least 10% SAA (p < 0.001) and 150 mEq DEB/kg in the diet (p = 0.11). Although feeding high-DEB level led to a remarkable decrease in villus height (p < 0.01) and goblet cell numbers (p < 0.001), supplementing the highest level of SAA improved the height of jejunal villus. During the entire trial period, average daily feed intake (ADFI) was increased by incremental SAA levels (p < 0.05). However, inclusion of 150 mEq/kg led to not only a remarkable increase (p < 0.0001) in both ADFI and average daily

  10. Stresses due to Squeeze Flow between Particles Surrounded by an Electrolyte Solution with Application to Lithium-Ion Batteries

    NASA Astrophysics Data System (ADS)

    Conlisk, A. T.; Zhang, Cong

    2013-11-01

    Large stresses are induced during lithium-ion battery charging and discharging, termed intercalation and deintercalation stresses. Current models of the stresses in lithium-ion batteries in the literature seldom consider the influence of the interaction between the particles within the electrodes on the stress distribution. The particles within lithium-ion battery electrodes can undergo relative motion with relative velocities of different magnitudes and directions. One important mode of motion manifests itself as two particles approaching each other. The interaction is mediated by the electrolyte between the particles. The relative motion of the particles induces significant pressures and the primary objective of this work is to propose a source of mechanical stresses as a consequence of the dynamic squeezing motion as opposed to a static environment considered in the battery literature. Other applications in the biomedical field are also discussed. Supported by DOE Graduate Automotive Technology Education (GATE), OSU Center for Automotive Research and OSU NSEC Center for the Affordable Nanoengineering of Polymeric Biomedical Devices.

  11. 49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Chloric acid solution or chlorine dioxide hydrate, frozen. 173.229 Section 173.229 Transportation Other Regulations Relating to Transportation PIPELINE AND... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When...

  12. 49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Chloric acid solution or chlorine dioxide hydrate, frozen. 173.229 Section 173.229 Transportation Other Regulations Relating to Transportation PIPELINE AND... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When...

  13. 49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Chloric acid solution or chlorine dioxide hydrate, frozen. 173.229 Section 173.229 Transportation Other Regulations Relating to Transportation PIPELINE AND... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When...

  14. 49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Chloric acid solution or chlorine dioxide hydrate, frozen. 173.229 Section 173.229 Transportation Other Regulations Relating to Transportation PIPELINE AND... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When...

  15. 49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Chloric acid solution or chlorine dioxide hydrate, frozen. 173.229 Section 173.229 Transportation Other Regulations Relating to Transportation PIPELINE AND... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When...

  16. Advanced Proton Conducting Polymer Electrolytes for Electrochemical Capacitors

    NASA Astrophysics Data System (ADS)

    Gao, Han

    Research on solid electrochemical energy storage devices aims to provide high performance, low cost, and safe operation solutions for emerging applications from flexible consumer electronics to microelectronics. Polymer electrolytes, minimizing device sealing and liquid electrolyte leakage, are key enablers for these next-generation technologies. In this thesis, a novel proton-conducing polymer electrolyte system has been developed using heteropolyacids (HPAs) and polyvinyl alcohol for electrochemical capacitors. A thorough understanding of proton conduction mechanisms of HPAs together with the interactions among HPAs, additives, and polymer framework has been developed. Structure and chemical bonding of the electrolytes have been studied extensively to identify and elucidate key attributes affecting the electrolyte properties. Numerical models describing the proton conduction mechanism have been applied to differentiate those attributes. The performance optimization of the polymer electrolytes through additives, polymer structural modifications, and synthesis of alternative HPAs has achieved several important milestones, including: (a) high proton mobility and proton density; (b) good ion accessibility at electrode/electrolyte interface; (c) wide electrochemical stability window; and (d) good environmental stability. Specifically, high proton mobility has been addressed by cross-linking the polymer framework to improve the water storage capability at normal-to-high humidity conditions (e.g. 50-80% RH) as well as by incorporating nano-fillers to enhance the water retention at normal humidity levels (e.g. 30-60% RH). High proton density has been reached by utilizing additional proton donors (i.e. acidic plasticizers) and by developing different HPAs. Good ion accessibility has been achieved through addition of plasticizers. Electrochemical stability window of the electrolyte system has also been investigated and expanded by utilizing HPAs with different heteroatoms

  17. Chemical evaluation of soil-solution in acid forest soils

    USGS Publications Warehouse

    Lawrence, G.B.; David, M.B.

    1996-01-01

    Soil-solution chemistry is commonly studied in forests through the use of soil lysimeters.This approach is impractical for regional survey studies, however, because lysimeter installation and operation is expensive and time consuming. To address these problems, a new technique was developed to compare soil-solution chemistry among red spruce stands in New York, Vermont, New Hampshire, Maine. Soil solutions were expelled by positive air pressure from soil that had been placed in a sealed cylinder. Before the air pressure was applied, a solution chemically similar to throughfall was added to the soil to bring it to approximate field capacity. After the solution sample was expelled, the soil was removed from the cylinder and chemically analyzed. The method was tested with homogenized Oa and Bs horizon soils collected from a red spruce stand in the Adirondack Mountains of New York, a red spruce stand in east-central Vermont, and a mixed hardwood stand in the Catskill Mountains of New York. Reproducibility, effects of varying the reaction time between adding throughfall and expelling soil solution (5-65 minutes) and effects of varying the chemical composition of added throughfall, were evaluated. In general, results showed that (i) the method was reproducible (coefficients of variation were generally < 15%), (ii) variations in the length of reaction-time did not affect expelled solution concentrations, and (iii) adding and expelling solution did not cause detectable changes in soil exchange chemistry. Concentrations of expelled solutions varied with the concentrations of added throughfall; the lower the CEC, the more sensitive expelled solution concentrations were to the chemical concentrations of added throughfall. Addition of a tracer (NaBr) showed that the expelled solution was a mixture of added solution and solution that preexisted in the soil. Comparisons of expelled solution concentrations with concentrations of soil solutions collected by zero-tension and

  18. Effect of electrolyte valency, alginate concentration and pH on engineered TiO₂ nanoparticle stability in aqueous solution.

    PubMed

    Loosli, Frédéric; Le Coustumer, Philippe; Stoll, Serge

    2015-12-01

    Agglomeration and disagglomeration processes are expected to play a key role on the fate of engineered nanoparticles in natural aquatic systems. These processes are investigated here in detail by studying first the stability of TiO2 nanoparticles in the presence of monovalent and divalent electrolytes at different pHs (below and above the point of zero charge of TiO2) and discussing the importance of specific divalent cation adsorption with the help of the DLVO theory as well as the importance of the nature of the counterions. Then the impact of one polysaccharide (alginate) on the stability of agglomerates formed under pH and water hardness representative of Lake Geneva environmental conditions is investigated. In these conditions the large TiO2 agglomerates (diameter>1μm) are positively charged due to Ca(2+) and Mg(2+) specific adsorption and alginate, which is negatively charged, adsorbs onto the agglomerate surface. Our results indicate that the presence of alginate at typical natural organic matter concentration (1-10 mg L(-1)) strongly modifies the TiO2 agglomerate (50 mg L(-1)) stability by inducing their partial and rapid disagglomeration. The importance of disagglomeration is found dependent on the alginate concentration with maximum of disagglomeration obtained for alginate concentration ≥8 mg L(-1) and leading to 400 nm fragments. From an environmental point of view partial restabilization of TiO2 agglomerates in the presence of alginate constitutes an important outcome. Disagglomeration will enhance their transport and residence time in aquatic systems which is an important step in the current knowledge on risk assessment associated to engineered nanoparticles. PMID:25726181

  19. Surface analytical study of CuInSe{sub 2} treated in Cd-containing partial electrolyte solution

    SciTech Connect

    Asher, S.E.; Ramanathan, K.; Wiesner, H.; Moutinho, H. Niles, D.W.

    1999-03-01

    Junction formation in CuInSe{sub 2} (CIS) has been studied by exposing thin films and single-crystal samples to solutions containing NH{sub 4}OH and CdSO{sub 4}. The treated samples were analyzed by secondary ion mass spectrometry to determine the amount and distribution of Cd deposited on the surface of the films. Cadmium is found to react with the surface for all the solution exposure times and temperatures studied. The reaction rapidly approaches the endpoint and remains relatively unchanged for subsequent solution exposure. Cadmium in-diffusion, as measured by secondary ion mass spectrometry, is obscured by topography effects in the thin-film samples and by ion-beam mixing and topography in the single-crystal sample. {copyright} {ital 1999 American Institute of Physics.}

  20. Surface analytical study of CuInSe[sub 2] treated in Cd-containing partial electrolyte solution

    SciTech Connect

    Asher, S.E.; Ramanathan, K.; Wiesner, H.; Moutinho, H. ) Niles, D.W. )

    1999-03-01

    Junction formation in CuInSe[sub 2] (CIS) has been studied by exposing thin films and single-crystal samples to solutions containing NH[sub 4]OH and CdSO[sub 4]. The treated samples were analyzed by secondary ion mass spectrometry to determine the amount and distribution of Cd deposited on the surface of the films. Cadmium is found to react with the surface for all the solution exposure times and temperatures studied. The reaction rapidly approaches the endpoint and remains relatively unchanged for subsequent solution exposure. Cadmium in-diffusion, as measured by secondary ion mass spectrometry, is obscured by topography effects in the thin-film samples and by ion-beam mixing and topography in the single-crystal sample. [copyright] [ital 1999 American Institute of Physics.