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Sample records for acidic chloride solutions

  1. REMOVAL OF CHLORIDE FROM ACIDIC SOLUTIONS USING NO2

    Chloride (Cl-) 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 (NO2) gas to effectively convert dissolved pyrochemical salt solutions to chloride-free solutions and improve recovery operations. An NO2 sparge has been shown to effectively remove Cl- from solutions containing 6-8 M acid (H+) and up to 5 M Cl-. 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+, the reaction of hydrochloric acid (HCl) with nitric acid (HNO3), facilitated by the presence of NO2, strongly affects the rate of Cl- removal. The effect of heating the acidic Cl- salt solution without pre-heating the NO2 gas has minimal effect on Cl- removal rates when the contact times between NO2 and the salt solution are on the order of seconds

  2. Indium sulfide precipitation from hydrochloric acid solutions of calcium and sodium chlorides

    The effect of precipitation duration, acid concentration, indium complexing with chloride ions on the process of indium sulfide chemical precipitation in hydrochloric acid solutions, precipitate composition and dispersity are studied. It is established that indium sulfide solubility increases in solutions with acid concentration exceeding 0.40-0.45 mol/l. Calcium and indium chloride addition to diluted hydrochloric solutions greatly increases the solubility of indium sulfide. The effect of calcium chloride on In2S3 solubility is higher than that of sodium chloride

  3. Chloride stress corrosion cracking of Alloy 600 in boric acid solutions

    The high nickel austenitic alloys are generally considered to have good resistance to chloride stress corrosion cracking. In the standard boiling magnesium chloride solution tests, alloys with more than 40% nickel are immune. Nevertheless, more recent data show that cracking can occur in both Alloys 600 and 690 if the solution is acidified. In other low pH media, such as boric acid solution at 100 deg C, transgranular and intergranular cracking are observed in Alloy 600 in the presence of minor concentrations of sodium chloride (2g/I). In concentrated boric acid at higher temperatures (250 and 290 deg C), intergranular cracking also occurs, either when the chloride concentration is high, or at low chloride contents and high oxygen levels. The role of pH and a possible specific action of boric acid are discussed, together with the influence of electrochemical potential. (author)

  4. Chloride stress corrosion cracking of Alloy 600 in boric acid solutions

    Berge, Ph. [Electricite de France, 92 - Paris la Defense (France); Noel, D.; Gras, J.M.; Prieux, B. [Electricite de France, 77 - Moret-sur-Loing (France). Direction des Etudes et Recherches

    1997-10-01

    The high nickel austenitic alloys are generally considered to have good resistance to chloride stress corrosion cracking. In the standard boiling magnesium chloride solution tests, alloys with more than 40% nickel are immune. Nevertheless, more recent data show that cracking can occur in both Alloys 600 and 690 if the solution is acidified. In other low pH media, such as boric acid solution at 100 deg C, transgranular and intergranular cracking are observed in Alloy 600 in the presence of minor concentrations of sodium chloride (2g/I). In concentrated boric acid at higher temperatures (250 and 290 deg C), intergranular cracking also occurs, either when the chloride concentration is high, or at low chloride contents and high oxygen levels. The role of pH and a possible specific action of boric acid are discussed, together with the influence of electrochemical potential. (author) 21 refs.

  5. Leaching of complex sulphide concentrate in acidic cupric chloride solutions

    M. TCHOUMOU; M. ROYNETTE

    2007-01-01

    The chemical analysis of a complex sulphide concentrate by emission spectrometry and X-ray diffraction shows that it contains essentially copper, lead, zinc and iron in the form of chalcopyrite, sphalerite and galena. A small amount of pyrite is also present in the ore but does not be detected with X-ray diffraction. The cupric chloride leaching of the sulphide concentrate at various durations and solid/liquid ratios at 100 ℃ shows that the rate of dissolution of the ore is the fastest in the first several hours, and after 12 h it does not evolve significantly. If oxygen is excluded from the aqueous cupric chloride solution during the leaching experiment at 100 ℃, the pyrite in the ore will not be leached. The determination of principal dissolved metals in the leaching liquor by flame atomic absorption spectrometry, and the chemical analysis of solid residues by emission spectrometry and X-ray diffraction allow to conclude that the rate of dissolution of the minerals contained in the complex sulphide concentrate are in the order of galena>sphalerite>chalcopyrite.

  6. Control and monitoring of the localized corrosion of zirconium in acidic chloride solutions

    Zirconium in acidic chloride solutions which are contaminated with ferric or cupric cations is prone to localized corrosion. This tendency can be reduced by ensuring that the zirconium surface is clean and smooth. In this paper, the effect of surface condition on the localized corrosion of zirconium in acidic chloride solutions is predicted with potentiodynamic scans. These predictions are confirmed by weight loss tests on various combinations of surface finish and acid concentrations. A real time indication of localized corrosion is seen by monitoring the electrochemical noise produced between two similar electrodes immersed in an acidic chloride solutions. Electrochemical noise monitoring correlates well with the predictions from potentiodynamic and weight loss experiments. The electrochemical noise results show that while an elevated (more anodic) potential caused by ferric ion contamination may be a necessary condition for localized corrosion, it is not a sufficient condition: A smooth, clean zirconium surface reduces the localized corrosion of zirconium

  7. The initial behaviour of freshly etched copper in modertely acid, aerated chloride solutions

    Bech-Nielsen, Gregers; Jaskula, M.; Chorkendorff, Ib;

    2002-01-01

    When freshly etched samples of various types of copper were exposed in moderately acid, aerated chloride solutions, two phenomena were observed. First the corrosion potential and the pH of the solution decreased over a shorter time, then the potential increased over a long period (600-1500 min...

  8. Stress corrosion cracking of AISI 321 stainless steel in acidic chloride solution

    Yanliang Huang

    2002-02-01

    The stress corrosion cracking (SCC) of AISI 321 stainless steel in acidic chloride solution was studied by slow strain rate (SSR) technique and fracture mechanics method. The fractured surface was characterized by cleavage fracture. In order to clarify the SCC mechanism, the effects of inhibitor KI on SCC behaviour were also included in this paper. A study showed that the inhibition effects of KI on SCC were mainly attributed to the anodic reaction of the corrosion process. The results of strain distribution in front of the crack tip of the fatigue pre-cracked plate specimens in air, in the blank solution (acidic chloride solution without inhibitor KI) and in the solution added with KI measured by speckle interferometry (SPI) support the unified mechanism of SCC and corrosion fatigue cracking (CFC).

  9. Ternary solution of sodium chloride, succinic acid and water; surface tension and its influence on cloud droplet activation

    J. Vanhanen; Hyvärinen, A.-P.; Anttila, T.; T. Raatikainen; Viisanen, Y; H. Lihavainen

    2008-01-01

    Surface tension of ternary solution of sodium chloride, succinic acid and water was measured as a function of both composition and temperature by using the capillary rise technique. Both sodium chloride and succinic acid are found in atmospheric aerosols, the former being main constituent of marine aerosol. Succinic acid was found to decrease the surface tension of water already at very low concentrations. Sodium chloride increased the surface tension linearly as a function of the concentrati...

  10. Ternary solution of sodium chloride, succinic acid and water ? surface tension and its influence on cloud droplet activation

    H. Lihavainen; Viisanen, Y; Anttila, T.; A.-P. Hyvärinen; J. Vanhanen

    2008-01-01

    Surface tension of ternary solution of sodium chloride, succinic acid and water was measured as a function of both composition and temperature by using the capillary rise technique. Both sodium chloride and succinic acid are found in atmospheric aerosols, the former being main constituent of marine aerosol. Succinic acid was found to decrease the surface tension of water already at very low concentrations. Sodium chloride increased the surface tension linearly as a function of the concentrati...

  11. Corrosion Behavior of Alloy 22 in Oxalic Acid and Sodium Chloride Solutions

    Day, S D; Whalen, M T; King, K J; Hust, G A; Wong, L L; Estill, J C; Rebak, R B

    2003-06-24

    Nickel based Alloy 22 (NO6022) is extensively used in aggressive industrial applications, especially due to its resistance to localized corrosion and stress corrosion cracking in high chloride environments. The purpose of this work was to characterize the anodic behavior of Alloy 22 in oxalic acid solution and to compare its behavior to sodium chloride (NaCl) solutions. Standard electrochemical tests such as polarization resistance and cyclic polarization were used. Results show that the corrosion rate of Alloy 22 in oxalic acid solutions increased rapidly as the temperature and the acid concentration increased. Extrapolation studies show that even at a concentration of 10{sup -4}M oxalic acid, the corrosion rate of Alloy 22 would be higher in oxalic acid than in 1 M NaCl solution. Alloy 22 was not susceptible to localized corrosion in oxalic acid solutions. Cyclic polarization tests in 1 M NaCl showed that Alloy 22 was susceptible to crevice corrosion at 90 C but was not susceptible at 60 C.

  12. Efficient acetylation of primary amines and amino acids in environmentally benign brine solution using acetyl chloride

    Kaushik Basu; Suchandra Chakraborty; Achintya Kumar Sarkar; Chandan Saha

    2013-05-01

    Acetyl chloride is one of the most commonly available and cheap acylating agent but its high reactivity and concomitant instability in water precludes its use to carry out acetylation in aqueous medium. The present methodology illustrates the efficient acetylation of primary amines and amino acids in brine solution by means of acetyl chloride under weakly basic condition in the presence of sodium acetate and/or triethyl amine followed by trituration with aqueous saturated bicarbonate solution. This effort represents the first efficient use of this most reactive but cheap acetylating agent to acetylate amines in excellent yields in aqueous medium. This is a potentially useful green chemical transformation where reaction takes place in environment-friendly brine solution leading to easy work-up and isolation of the amide derivatives. Mechanistic rationale of this methodology is also important.

  13. Protection of copper surface with phytic acid against corrosion in chloride solution.

    Peca, Dunja; Pihlar, Boris; Ingrid, Milošev

    2014-01-01

    Phytic acid (inositol hexaphosphate) was tested as a corrosion inhibitor for copper in 3% sodium chloride. Phytic acid is a natural compound derived from plants, it is not toxic and can be considered as a green inhibitor. Electrochemical methods of linear polarization and potentiodynamic polarization were used to study the electrochemical behaviour and evaluate the inhibition effectiveness. To obtain the optimal corrosion protection the following experimental conditions were investigated: effect of surface pre-treatment (abrasion and three procedures of surface roughening), pre-formation of the layer of phytic acid, time of immersion and concentration of phytic acid. To evaluate the surface pre-treatment procedures the surface roughness and contact angle were measured. Optimal conditions for formation of phytic layer were selected resulting in the inhibition effectiveness of nearly 80%. Morphology and composition of the layer were further studied by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The layer of phytic acid with thickness in the nanometer range homogeneously covers the copper surface. The obtained results show that this natural compound can be used as a mildly effective corrosion inhibitor for copper in chloride solution. PMID:25286201

  14. Leaching of lead from zinc leach residue in acidic calcium chloride aqueous solution

    Wang, Le; Mu, Wen-ning; Shen, Hong-tao; Liu, Shao-ming; Zhai, Yu-chun

    2015-05-01

    A process with potentially reduced environmental impacts and occupational hazards of lead-bearing zinc plant residue was studied to achieve a higher recovery of lead via a cost-effective and environmentally friendly process. This paper describes an optimization study on the leaching of lead from zinc leach residue using acidic calcium chloride aqueous solution. Six main process conditions, i.e., the solution pH value, stirring rate, concentration of CaCl2 aqueous solution, liquid-to-solid (L/S) ratio, leaching temperature, and leaching time, were investigated. The microstructure and components of the residue and tailing were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). On the basis of experimental results, the optimum reaction conditions were determined to be a solution pH value of 1, a stirring rate of 500 r·min-1, a CaCl2 aqueous solution concentration of 400 g·L-1, a liquid-to-solid mass ratio of 7:1, a leaching temperature of 80°C, and a leaching time of 45 min. The leaching rate of lead under these conditions reached 93.79%, with an iron dissolution rate of 19.28%. Silica did not take part in the chemical reaction during the leaching process and was accumulated in the residue.

  15. Radiochemical extraction of mercury(II) from acidic chloride solutions using dialkylsulphides

    The liquid-liquid extraction behavior of Hg(II) from aqueous acidic chloride solutions has been investigated by tracer techniques using dialkylsulphides (R2S) namely, dibutylsulphide (DBS) and dioctylsulphide (DOS) as extractants. These extraction data have been analyzed by both graphical and theoretical methods by taking into account complexation of the metal ion in the aqueous phase with inorganic ligands and all plausible complexes extracted into the organic phase. The results clearly indicate that Hg(II) is extracted into xylene as HgCl2 x nDBS/nDOS (where n = 2 and 3). The equilibrium constants of the extracted complexes have been deduced by non-linear regression analysis. The separation possibilities of Hg(II) from other metal ions viz. Ca(II), Mg(II), Ba(II) and Fe(III), which are present in the industrial wastes of the chlor-alkali industry has also been discussed. (author)

  16. EIS study on pitting corrosion of 7150 aluminum alloy in sodium chloride and hydrochloric acid solution

    Peng, G.S; Chen, K.H.; Fang, H.C.; Chao, H.; Chen, S.Y. [State Key Laboratory for Powder Metallurgy, Central South University, Hunan (China)

    2010-09-15

    The pitting corrosion behavior of 7150 aluminum alloy was studied by electrochemical impedance spectroscopy (EIS) in the sodium chloride and hydrochloric acid solution. Based on EIS features and corrosion morphologies as well as corrosion potential, the process of pitting corrosion could be clearly divided into four stages: at the first stage, the Nyquist diagram was composed of two overlapping capacitive loops at the high-medial frequency and one inductive loop at the low frequency. At the second stage (metastable pits developing stage), there existed one small capacitive loop at the high frequency and one big capacitive loop at the medial frequency. At the third stage (stable pits developing stage), two time constants were more clearly distinguished, corresponding to two obvious capacitive loops. At the fourth stage, there appeared one capacitive loop, attributing to uniform corrosion. An equivalent circuit was designed to fit EIS, and the experimental results and the fitted results had good correspondence. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  17. Corrosion Behavior of Alloy 22 in Chloride Solutions Containing Organic Acids

    Carranza, R M; Giordano, C M; Rodr?guez, M A; Rebak, R B

    2005-11-04

    Alloy 22 (N06022) is a nickel based alloy containing alloying elements such as chromium, molybdenum and tungsten. It is highly corrosion resistant both under reducing and under oxidizing conditions. Electrochemical studies such as electrochemical impedance spectroscopy (EIS) were performed to determine the corrosion behavior of Alloy 22 in 1M NaCl solutions at various pH values from acidic to neutral at 90 C. Tests were also carried out in NaCl solutions containing oxalic acid or acetic acid. It is shown that the corrosion rate of Alloy 22 was higher in a solution containing oxalic acid than in a solution of the same pH acidified with HCl. Acetic acid was not corrosive to Alloy 22. The corrosivity of oxalic acid was attributed to its capacity to form stable complex species with metallic cations from Alloy 22.

  18. Sorption of uranium(VI) ions from hydrochloric acid and ammonium chloride solutions by anion exchangers

    The sorption of macroscopic quantities of uranium from solutions of UO2Cl2 containing HCl and NH4Cl in concentrations from 0.0 to 6.0 M by the AV-17 x 8, AV-16G, EDE-10P, AN-31, AN-2F, AN22, and AN-251 anion exchangers has been investigated under static conditions. The sorption isotherms are described by an equation similar to Freundlich's equation: K/sub d/ = K tilde x C/sub eq/sup 1/z/ or log K/sub d/ = log K tilde + 1/z x log C/sub eq/. Equations describing the dependence of the sorbability (or K/sub d/) on the equilibrium concentration of uranium in the solution have been obtained with the aid of the least-squares method. Conclusions regarding the chemistry of the exchange of uranium ions on anion exchangers in chloride solutions have been drawn on the basis of the UV spectra of the original solutions and the IR spectra of the ion exchangers obtained in this work, as well as the established general laws governing sorption

  19. Sorption of uranium(VI) ions from hydrochloric acid and ammonium chloride solutions by anion exchangers

    Pakholkov, V.S.; Denisova, L.A.; Rychkov, V.N.; Kurnosenko, N.A.

    1988-01-01

    The sorption of macroscopic quantities of uranium from solutions of UO/sub 2/Cl/sub 2/ containing HCl and NH/sub 4/Cl in concentrations from 0.0 to 6.0 M by the AV-17 x 8, AV-16G, EDE-10P, AN-31, AN-2F, AN22, and AN-251 anion exchangers has been investigated under static conditions. The sorption isotherms are described by an equation similar to Freundlich's equation: K/sub d/ = K tilde x C/sub eq/sup 1/z/ or log K/sub d/ = log K tilde + 1/z x log C/sub eq/. Equations describing the dependence of the sorbability (or K/sub d/) on the equilibrium concentration of uranium in the solution have been obtained with the aid of the least-squares method. Conclusions regarding the chemistry of the exchange of uranium ions on anion exchangers in chloride solutions have been drawn on the basis of the UV spectra of the original solutions and the IR spectra of the ion exchangers obtained in this work, as well as the established general laws governing sorption.

  20. Effects of applied potential on the stress corrosion cracking behavior of 7003 aluminum alloy in acid and alkaline chloride solutions

    Zhang, Xiao-yan; Song, Ren-guo; Sun, Bin; Lu, Hai; Wang, Chao

    2016-07-01

    Potentiodynamic polarization tests and slow strain rate test (SSRT) in combination with fracture morphology observations were conducted to investigate the stress corrosion cracking (SCC) behavior of 7003 aluminum alloy (AA7003) in acid and alkaline chloride solutions under various applied potentials ( E a). The results show that AA7003 is to a certain extent susceptible to SCC via anodic dissolution (AD) at open-circuit potential (OCP) and is highly susceptible to hydrogen embrittlement (HE) at high negative E a in the solutions with pH levels of 4 and 11. The susceptibility increases with negative shift in the potential when E a is less than -1000 mV vs. SCE. However, the susceptibility distinctly decreases because of the inhibition of AD when E a is equal to -1000 mV vs. SCE. In addition, the SCC susceptibility of AA7003 in the acid chloride solution is higher than that in the alkaline solution at each potential. Moreover, the effect of hydrogen on SCC increases with increasing hydrogen ion concentration.

  1. Structural transformations of the synthetic salt 4`, 7-dihydroxyflavylium chloride in acid and basic aqueous solutions. Part 1-Ground state

    Pina, F.; Benedito, L.; Melo, M.J.; Parola, A.J. [Centro de Quimica Fina e Biotecnologia. Departamento de Quimica FCT/UNL, Portugal (Portugal); Lima, J.C.; Macanita, A.L. [Instituto de Tecnologia Quimica e Biologica, Portugal (Portugal)

    1997-09-01

    A complete study of the structural pH dependent transformations of the synthetic flavylium salt 4`-7-dihydroxyflavylium chloride (DHF), occurring in aqueous solutions, including the basic region, is described. The kinetics study of the transformations occurring in acidic media (quinoidal base (A) {l_reversible} flavylium cation (AH{sup +}) {l_reversible} hemiacetal (B) {l_reversible} cis-chalcone (C-cis) {l_reversible} trans-chalcone (C-trans)) allowed to conclude that the cis-transisomerization is faster than the tautomerization and the hydration processes, which is unique in the anthocyanins family. Results obtained with the parent compound 4`-7-dimethoxyflavylium chloride (DMF)with relevance to this study are also presented. In equilibrated basic solutions the existence of acid-base equilibria involving the trans-Chalcone (C-trans) and its conjugated bases, (C-trans, and C``2-trans), was detected. Freshly prepared solutions at pH>7 show also the presence of a transient species identified as the ionized quinoidal base (A``-), which is almost completely converted into C``2-trans with a Ph dependent rate constant, (Author) 17 refs.

  2. Permeability of solutes through cellophanes grafted with vinyl monomers. I. Diffusion of potassium chloride, urea, and uric acid

    The diffusive permeability of potassium chloride, urea, and uric acid through cellophanes grafted with acrylamide, acrylic acid, styrene, and N-vinyl-2-pyrrolidone by γ-ray irradiation was studied. The diffusive permeability coefficients of the permeants through the grafted cellophanes were increased with increase in hydration of the grafted membranes, except for the permeation of potassium chloride through cellophanes grafted with acrylic acid. The permeation of potassium chloride, urea, and uric acid through the various grafted cellophanes is explained by the free volume concept of homogeneously water-swollen membranes. However, the behavior of the permeation of potassium chloride through cellophane grafted with acrylic acid deviated from that of nonionic membranes because of the contribution of the electrical interaction between electrolyte and charge of the membrane. 4 figures, 3 tables

  3. Effects of hydrogen and surface dislocation on active dissolution of deformed 304 austenitic stainless steel in acid chloride solution

    Research highlights: → An active dissolution model was proposed by the stored strain energy and electron work function. → An significant effect of plastic deformation on active dissolution was observed. → The synergistic effect between the dissolved hydrogen and applied stress is negligible. → The change of surface morphology due to dislocation made the electron more active. - Abstract: The mechanochemical effects between dissolved hydrogen and deformation on active dissolution of 304 stainless steel in acid chloride solution were investigated by use of constant loading test method. A theoretical model was proposed in terms of the stored strain energy and electron work function. Results indicated that active dissolution was affected mainly by Gibbs free energy produced by the part of plastic deformation and surface dislocation structure. A good agreement between the prediction and test results revealed that the synergistic effect of stress and dissolved hydrogen only promoted the process of active dissolution.

  4. A new dioxime corrosion inhibitor for the protection and conservation of copper: synthesis, characterization and evaluation in acidic chloride solution

    Abu-Baker, Ahmad N.; Al-Qudah, Mahmoud A.

    2016-08-01

    This study aimed to investigate a new dioxime compound as a corrosion inhibitor for copper. The compound (4,6-dihydroxy benzene-1,3-dicarbaldehyde dioxime) was synthesized and characterized by nuclear magnetic resonance spectroscopy. Electrochemical impedance spectroscopy and potentiodynamic polarization measurements were used to compare the dioxime compound with benzotriazole for their effectiveness as corrosion inhibitors for copper in 0.1 M HCl solution. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used to investigate the bonding mechanisms and morphological changes of the two inhibitors on the copper surface. The electrochemical techniques showed that the new dioxime compound was more effective than benzotriazole in inhibiting copper corrosion in the acidic chloride medium. The FTIR and SEM results indicated that the dioxime compound was able to coordinate with copper ions and formed a protective film on the copper surface. It was concluded that the new dioxime compound proved effectiveness to be used as a corrosion inhibitor for the protection and conservation of copper.

  5. Kinetic and equilibrium studies of the removal of cadmium ions from acidic chloride solutions by hydrophobic pyridinecarboxamide extractants

    Liquid-liquid extraction of cadmium(II) from acidic chloride solutions was carried out with alkyl derivatives of pyridinecarboxamide in toluene with addition of 2-ethylhexan-1-ol as modifier. Equilibrium as well as kinetic studies was performed. The kinetic studies of a Cd(II) extraction process were carried out with a Lewis cell having a constant interfacial area. Cadmium(II) concentration in the aqueous phases was determined by atomic absorption spectroscopy (Varian SPECTR AA800). The results of equilibrium experiments showed that cadmium(II) was quantitatively extracted with N,N-dihexylpyridine-3-carboxamide whereas the derivative N,N-dihexylpyridine-2-carboxamide was not able to transfer Cd(II) ions from the aqueous phase to the organic one. Thus, the kinetics of extraction and the initial extraction rate were examined only in the systems with N,N-dihexylpyridine-3-carboxamide. The obtained experimental data as well as the calculated values of mass transfer coefficients suggest that the investigated process of extraction of Cd(II) by means of pyridinecarboxamide as extractant occurs in the mixed diffusion-kinetic region. Moreover, the results of adsorption studies indicated that the extraction of Cd(II) with a hydrophobic extractant should be considered as an interfacial process.

  6. Influence of chloride ions on the open circuit potentials of chromium in deaerated sulfuric acid solutions

    BORE JEGDIC

    2006-11-01

    Full Text Available Open circuit potential measurements and cyclic voltammetry of chromium in deaerated aqueous H2SO4 solution of pH 1 without and containing NaCl in the concentration range 0.5 – 4 M revealed that chromium exhibits two stable open circuit potentials having the character of a Wagner–Traud corrosion potential. One, Ecorr.1, was established on the passive surface formed by exposing Cr previously to air or passivated potentiostacially in a controlled manner, and the second one, Ecorr.2, at the bare Cr surface obtained by prolonged cathodic activation. There is a small difference in the Ecorr.1 values as a function of the passive layer properties. Addition of NaCl accelerates the hydrogen evolution reaction on the passive surface to some extent, while the same reaction on the bare surface was not affected by NaCl. On the other hand, presence of NaCl accelerates the anodic reaction on the bare surface, and it activates the dissolution of the passive layer so that the passive currents increase with addition of NaCl. This effect is so large that at concentration of NaCl larger than 3 M, the destruction of the passive layer was so fast that in a matter of seconds the Cr was activated, and the only one stable corrosion potential observed was Ecorr.2. No pitting of Cr in the presence of NaCl was observed up to the transpassive potentials.

  7. Liquid-liquid extraction/separation of platinum(IV) and rhodium(III) from acidic chloride solutions using tri-iso-octylamine

    Liquid-liquid extraction/separation of platinum(IV) and rhodium(III) from acidic chloride solutions was carried out using tri-iso-octylamine (Alamine 308) as an extractant diluted in kerosene. The percentage extraction of platinum(IV) and rhodium(III) increased with increase in acid concentration up to 8 mol L-1. However, at 10 mol L-1 HCl concentration, the extraction behavior was reversed, indicating the solvation type mechanism during extraction. The quantitative extraction of ∼98% platinum(IV) and 36% rhodium(III) was achieved with 0.01 mol L-1 Alamine 308. The highest separation factor (S.F. = 184.7) of platinum(IV) and rhodium(III) was achieved with 0.01 mol L-1 Alamine 308 at 1.0 mol L-1 of hydrochloric acid concentration. Alkaline metal salts like sodium chloride, sodium nitrate, sodium thiocyanate, lithium chloride, lithium nitrate, potassium chloride and potassium thiocyanate used for the salting-out effect. LiCl proved as best salt for the extraction of platinum(IV). Temperature effect demonstrates that the extraction process is exothermic. Hydrochloric acid and thiourea mixture proved to be better stripping reagents when compared with other mineral acids and bases.

  8. EQCM study of the electrodeposition of manganese in the presence of ammonium thiocyanate in chloride-based acidic solutions

    Diaz-Arista, P. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica (CIDETEQ), Parque Tecnologico Sanfandila, Pedro Escobedo, Queretaro, A.P. 064, C.P. 76700, Queretaro (Mexico); Antano-Lopez, R. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica (CIDETEQ), Parque Tecnologico Sanfandila, Pedro Escobedo, Queretaro, A.P. 064, C.P. 76700, Queretaro (Mexico); Meas, Y. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica (CIDETEQ), Parque Tecnologico Sanfandila, Pedro Escobedo, Queretaro, A.P. 064, C.P. 76700, Queretaro (Mexico); Ortega, R. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica (CIDETEQ), Parque Tecnologico Sanfandila, Pedro Escobedo, Queretaro, A.P. 064, C.P. 76700, Queretaro (Mexico); Chainet, E. [LEPMI, ENSEEG, 1130, rue de la piscine, BP 45, 38402 Saint Martin d' Heres (France); Ozil, P. [LEPMI, ENSEEG, 1130, rue de la piscine, BP 45, 38402 Saint Martin d' Heres (France); Trejo, G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica (CIDETEQ), Parque Tecnologico Sanfandila, Pedro Escobedo, Queretaro, A.P. 064, C.P. 76700, Queretaro (Mexico)]. E-mail: gtrejo@cideteq.mx

    2006-06-01

    The influence of ammonium thiocyanate (NH{sub 4}SCN) on the mechanism of manganese electrodeposition from a chloride-based acidic solution was investigated by cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). The EQCM data were represented as plots d{delta}m dt {sup -1} versus E, known as massograms. Because massograms are not affected by interference from the hydrogen evolution reaction, they clearly show the manganese reduction and oxidation processes. By comparing the voltammograms with their corresponding massograms, it was possible to differentiate mass changes due to faradaic processes from those due to non-faradaic processes. Morphology, chemical composition and structure of the manganese deposits formed in different potential ranges were analyzed by scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), and X-ray diffraction (XRD). The results showed that in the absence of NH{sub 4}SCN, Mn(OH){sub 2(s)} is formed in the potential range -1.1 to -0.9 V due to the hydrogen evolution reaction in this region. At more cathodic potentials, the deposition of {beta}-manganese and the inclusion of Mn(OH){sub 2(s)} into the deposit occur; both of these species underwent dissolution by non-faradaic processes during the anodic scan. In the presence of NH{sub 4}SCN, the formation of {alpha}- and {gamma}-manganese was observed. When the potential was {<=}-1.8 V and [NH{sub 4}SCN] exceeded 0.3 M, the {alpha}-manganese phase was favored.

  9. Solubility of tungstic acid and species of tungsten transfer in sodium chloride solutions at 25 Deg C

    Solubility of tungstic acid at room temperature in aqueous solutions with different content of Na+ and Cl- ions in pH range from 0.1 to 7.3 was determined using data of colorimetric analysis. It was ascertained that tungstic acid solubility increases with pH growth and increase in sodium content. Thermodynamic equilibrium constants for diverse tungsten-containing species existing in the solution at 3.5< pH<6 were calculated on the basis of experimental data. Dissociation and complexing reactions constants of tungstic acid were estimated

  10. Hydrazino-methoxy-1,3,5-triazine Derivatives’ Excellent Corrosion Organic Inhibitors of Steel in Acidic Chloride Solution

    Ayman El-Faham

    2016-06-01

    Full Text Available The corrosion inhibition performance of 2-hydrazino-4,6-dimethoxy-1,3,5-tirazine (DMeHT, 2,4-dihydrazino-6-methoxy-1,3,5-triaizine (DHMeT, and 2,4,6-tridydrazino-1,3,5-triaizne (TH3 on steel corrosion in acidic media was examined using electrochemical techniques. The results showed 2,4-Ddihydrazino-6-methoxy-1,3,5-triaizine (DHMeT gave the best corrosion protection performance among the other hydrazino derivatives even at a low concentration of 25 ppm (95%. The number of hydrazino groups play an important role in the corrosion inhibition, where the two hydrazine groups increased the electrostatic interactions between the protonated tested compounds, the negatively charged steel surface resulted from the adsorption of the chloride anions, and the presence of the methoxy group made the compound more reliable for formation of film protection on the surface of steel through the lone pair of oxygen atoms. Electrochemical Impedance Spectroscopy (EIS measurements suggested that the corrosion process of steel in presence of the hydrazino-s-triazine derivatives (TH3, DMeHT and DHMeT were being controlled by the charge transfer reaction. Polarization curves indicated that the examined TH3, DMeHT and DHMeT behaved as mixed type inhibitors.

  11. Hydrazino-methoxy-1,3,5-triazine Derivatives' Excellent Corrosion Organic Inhibitors of Steel in Acidic Chloride Solution.

    El-Faham, Ayman; Osman, Sameh M; Al-Lohedan, Hamad A; El-Mahdy, Gamal A

    2016-01-01

    The corrosion inhibition performance of 2-hydrazino-4,6-dimethoxy-1,3,5-tirazine (DMeHT), 2,4-dihydrazino-6-methoxy-1,3,5-triaizine (DHMeT), and 2,4,6-tridydrazino-1,3,5-triaizne (TH₃) on steel corrosion in acidic media was examined using electrochemical techniques. The results showed 2,4-Ddihydrazino-6-methoxy-1,3,5-triaizine (DHMeT) gave the best corrosion protection performance among the other hydrazino derivatives even at a low concentration of 25 ppm (95%). The number of hydrazino groups play an important role in the corrosion inhibition, where the two hydrazine groups increased the electrostatic interactions between the protonated tested compounds, the negatively charged steel surface resulted from the adsorption of the chloride anions, and the presence of the methoxy group made the compound more reliable for formation of film protection on the surface of steel through the lone pair of oxygen atoms. Electrochemical Impedance Spectroscopy (EIS) measurements suggested that the corrosion process of steel in presence of the hydrazino-s-triazine derivatives (TH₃, DMeHT and DHMeT) were being controlled by the charge transfer reaction. Polarization curves indicated that the examined TH₃, DMeHT and DHMeT behaved as mixed type inhibitors. PMID:27258241

  12. Laboratory stress corrosion cracking studies with sulfur acids and chlorides

    Baylor, V.B.

    1985-10-01

    Stress corrosion cracking (SCC) caused by polythionic acid and/or chlorides has occurred in coal liquefaction pilot plants. This problem is also common in refineries and has been extensively researched. This study examines: (1) the relationship of the ASTM standard ferric sulfate-sulfuric acid test for determining sensitization to resistance to polythionic SCC; (2) the cracking resistance of higher-alloy. Fe-Ni-Cr materials and common austenitic stainless steels (SS); and (3) the effect of chloride concentrations up to 1% in polythionic acid solutions on cracking behavior. The ferric sulfatesulfuric acid test can be used as an acceptance test for materials resistant to polythionic acid SCC. More highly alloyed materials were more resistant to sensitization than most austenitic SS and were virtually unattacked in polythionic acid solutions containing up to 1% chloride. Chloride increased the corrosion rate and caused localized pitting but it did not significantly affect the number of failures or the failure mode.

  13. Determination of chloride in uranium solutions

    Danse, A.; Stoch, H.; Steele, T.W.

    1967-05-15

    Thiocyanate is first removed by precipitation with a small excess of a copper solution, and the cations are removed by passing the filtrate through a cation-exchange resin. The chloride is determined in the eluate by a potentiometric titration in which silver nitrate solution is used.

  14. Catalytic Conversion of Cellulose to Levulinic Acid by Metal Chlorides

    Beixiao Zhang

    2010-08-01

    Full Text Available The catalytic performance of various metal chlorides in the conversion of cellulose to levulinic acid in liquid water at high temperatures was investigated. The effects of reaction parameters on the yield of levulinic acid were also explored. The results showed that alkali and alkaline earth metal chlorides were not effective in conversion of cellulose, while transition metal chlorides, especially CrCl3, FeCl3 and CuCl2 and a group IIIA metal chloride (AlCl3, exhibited high catalytic activity. The catalytic performance was correlated with the acidity of the reaction system due to the addition of the metal chlorides, but more dependent on the type of metal chloride. Among those metal chlorides, chromium chloride was found to be exceptionally effective for the conversion of cellulose to levulinic acid, affording an optimum yield of 67 mol % after a reaction time of 180 min, at 200 °C, with a catalyst dosage of 0.02 M and substrate concentration of 50 wt %. Chromium metal, most of which was present in its oxide form in the solid sample and only a small part in solution as Cr3+ ion, can be easily separated from the resulting product mixture and recycled. Finally, a plausible reaction scheme for the chromium chloride catalyzed conversion of cellulose in water was proposed.

  15. Hydrolysis of ferric chloride in solution

    The Detox trademark process uses concentrated ferric chloride and small amounts of catalysts to oxidize organic compounds. It is under consideration for oxidizing transuranic organic wastes. Although the solution is reused extensively, at some point it will reach the acceptable limit of radioactivity or maximum solubility of the radioisotopes. This solution could be cemented, but the volume would be increased substantially because of the poor compatibility of chlorides and cement. A process has been developed that recovers the chloride ions as HCl and either minimizes the volume of radioactive waste or permits recycling of the radioactive chlorides. The process involves a two-step hydrolysis at atmospheric pressure, or preferably under a slight vacuum, and relatively low temperature, about 200 degrees C. During the first step of the process, hydrolysis occurs according to the reaction below: FeCl3liquid + H2O → FeOClsolid + 2 HClgas During the second step, the hot, solid, iron oxychloride is sprayed with water or placed in contact with steam, and hydrolysis proceeds to the iron oxide according to the following reaction: 2 FeOClsolid + H2O → Fe2O3solid + 2 HClgas. The iron oxide, which contains radioisotopes, can then be disposed of by cementation or encapsulation. Alternately, these chlorides can be washed off of the solids and can then either be recycled or disposed of in some other way

  16. Effects of nitrogen on the passivation of nickel-free high nitrogen and manganese stainless steels in acidic chloride solutions

    The role of nitrogen on the passivation of nickel-free high nitrogen and manganese stainless steels was investigated in 0.5 M H2SO4, 3.5% NaCl and 0.5 M H2SO4 + 0.5 M NaCl solutions using potentiodynamic polarization, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy techniques. The passive film stability was enhanced in 0.5 M H2SO4 and the pitting resistance was improved in 3.5% NaCl solution by more nitrogen addition. The influence of nitrogen extended the whole anodic polarization region in 0.5 M H2SO4 + 0.5 M NaCl solution, as demonstrated by the enhanced dissolution resistance, promoted adsorption and passivation process, improved film protection and pitting resistance with increasing nitrogen content. Possible mechanisms relating to the role of nitrogen in different potential regions were discussed.

  17. Viscosity and density tables of sodium chloride solutions

    Fair, J.A.; Ozbek, H. (comps.)

    1977-04-01

    A file is presented containing tabulated data extracted from the scientific literature on the density and viscosity of aqueous sodium chloride solutions. Also included is a bibliography of the properties of aqueous sodium chloride solutions. (MHR)

  18. Hydrolysis of ferric chloride in solution

    Lussiez, G.; Beckstead, L.

    1996-11-01

    The Detox{trademark} process uses concentrated ferric chloride and small amounts of catalysts to oxidize organic compounds. It is under consideration for oxidizing transuranic organic wastes. Although the solution is reused extensively, at some point it will reach the acceptable limit of radioactivity or maximum solubility of the radioisotopes. This solution could be cemented, but the volume would be increased substantially because of the poor compatibility of chlorides and cement. A process has been developed that recovers the chloride ions as HCl and either minimizes the volume of radioactive waste or permits recycling of the radioactive chlorides. The process involves a two-step hydrolysis at atmospheric pressure, or preferably under a slight vacuum, and relatively low temperature, about 200{degrees}C. During the first step of the process, hydrolysis occurs according to the reaction below: FeCl{sub 3 liquid} + H{sub 2}O {r_arrow} FeOCl{sub solid} + 2 HCl{sub gas} During the second step, the hot, solid, iron oxychloride is sprayed with water or placed in contact with steam, and hydrolysis proceeds to the iron oxide according to the following reaction: 2 FeOCl{sub solid} + H{sub 2}O {r_arrow} Fe{sub 2}O{sub 3 solid} + 2 HCl{sub gas}. The iron oxide, which contains radioisotopes, can then be disposed of by cementation or encapsulation. Alternately, these chlorides can be washed off of the solids and can then either be recycled or disposed of in some other way.

  19. Removal of iron contaminant from zirconium chloride solution

    This patent describes a process for eliminating iron contaminant from an aqueous zirconium chloride solution that has been contaminated with FeCl3 in a plant in which zirconium and hafnium chloride solutions are separated by a main MINK solvent extraction system and the FeCl3 is normally removed from the zirconium chloride solution by a secondary MINK solvent extraction system

  20. Solubility and physic-chemical properties of NaH2PO4 in phosphoric acid, sodium chloride and their mixture solutions at T = (298.15 and 313.15) K

    Highlights: • Solubility and physic-chemical properties of NaH2PO4 in H3PO4 solutions were obtained. • Solubility and physic-chemical properties of NaH2PO4 in NaCl solutions were obtained were obtained. • Solubility and physic-chemical properties of NaH2PO4 in mixed solutions of H3PO4 and NaCl were obtained. • The solubility diagrams and the physic-chemical property diagrams were plotted. - Abstract: In this study, solubility and physic-chemical properties of sodium dihydrogen phosphate in sodium chloride, phosphoric acid and their mixture solutions at T = (298.15 and 313.15) K have been investigated by using isothermal dissolution method. In the three systems, the solubility of NaH2PO4 always increases with the temperature increasing and decreases with molar concentration of phosphoric acid (sodium chloride) increasing because of the same ion effect. Solubility data of sodium dihydrogen phosphate in the mixed solution of sodium chloride and phosphoric acid is basically required for designing and optimizing the solvent extraction process in the industrial production

  1. Extraction of Ca (II and Mg (II from Hydrochloric Acid Solutions by N, N-Dioctyl-1-Octan Ammonium Chloride in Methyl Isobutyl Ketone

    Fatmir Faiku

    2012-01-01

    Full Text Available Problem statement: Amines as organic molecules are able to form complexes with metals ions and this is the reason why we can use them to extract metals ions from hydrometallurgical solutions. Approach: Based on that, we have investigated the extraction of Calcium and Magnesium with N, N-dioctyl-1-octan ammonium chloride from the mixture of elements (Ca and Mg prepared in artificial manner. We have investigated the influence of HCl concentration and salts (NaCl, NaI and CH3COONa concentration in extraction of two elements (Ca and Mg from water solutions. All extractions were done from HCl water solutions with c = 3, 6 and 9 mol L-1 and in presence of NaCl, NaI and CH3COONa salts, which we prepared in different concentrations. Results: Extraction of Calcium from NaCl solution move from 18-30%, from NaI solution 55-77% and from CH3COONa solution 50-71%. Extraction of Magnesium from NaCl solution move from 3-12%, from NaI solution 0-11% and from CH3COONa solution 0-8%. Conclusion: As optimal condition to separate Calcium from Magnesium is the extraction of Calcium from HCl solution with concentration 9 mol L-1 in presence of NaI with concentration of 60 g L-1. Using these condition 77% of Calcium was in organic phase and all of magnesium remains in water phase.

  2. Green process to recover magnesium chloride from residue solution of potassium chloride production plant

    Lin WANG; Yunliang HE; Yanfei WANG; Ying BAO; Jingkang WANG

    2008-01-01

    The green process to recover magnesium chlor-ide from the residue solution of a potassium chloride pro-duction plant, which comes from the leach solution of a potash mine in Laos, is designed and optimized. The res-idue solution contains magnesium chloride above 25 wt-%, potassium chloride and sodium chloride together below 5 wt-% and a few other ions such as Br-, SO2-4and Ca2+. The recovery process contains two steps: the previous impurity removal operation and the two-stage evapora-tion-cooling crystallization procedure to produce magnes-ium chloride. The crystallized impurity carnallite obtained from the first step is recycled to the potassium chloride plant to recover the potassium salt. The developed process is a zero discharge one and thus fulfills the requirements for green chemical industrial production. The produced magnesium chloride is up to industrial criteria.

  3. Extraction of Ca (II) and Mg (II) from Hydrochloric Acid Solutions by N, N-Dioctyl-1-Octan Ammonium Chloride in Methyl Isobutyl Ketone

    Fatmir Faiku; Arben Haziri; Imer Haziri; Sali Aliu; Nita Sopa

    2012-01-01

    Problem statement: Amines as organic molecules are able to form complexes with metals ions and this is the reason why we can use them to extract metals ions from hydrometallurgical solutions. Approach: Based on that, we have investigated the extraction of Calcium and Magnesium with N, N-dioctyl-1-octan ammonium chloride from the mixture of elements (Ca and Mg) prepared in artificial manner. We have investigated the influence of HCl concentration and salts (NaCl, NaI and CH3COONa) concentratio...

  4. The passivation of calcite by acid mine water. Column experiments with ferric sulfate and ferric chloride solutions at pH 2

    Column experiments, simulating the behavior of passive treatment systems for acid mine drainage, have been performed. Acid solutions (HCl or H2SO4, pH 2), with initial concentrations of Fe(III) ranging from 250 to 1500 mg L-1, were injected into column reactors packed with calcite grains at a constant flow rate. The composition of the solutions was monitored during the experiments. At the end of the experiments (passivation of the columns), the composition and structure of the solids were measured. The dissolution of calcite in the columns caused an increase in pH and the release of Ca into the solution, leading to the precipitation of gypsum and Fe-oxyhydroxysulfates (Fe(III)-SO4-H+ solutions) or Fe-oxyhydroxychlorides (Fe(III)-Cl-H+ solutions). The columns worked as an efficient barrier for some time, increasing the pH of the circulating solutions from 2 to ∼6-7 and removing its metal content. However, after some time (several weeks, depending on the conditions), the columns became chemically inert. The results showed that passivation time increased with decreasing anion and metal content of the solutions. Gypsum was the phase responsible for the passivation of calcite in the experiments with Fe(III)-SO4-H+ solutions. Schwertmannite and goethite appeared as the Fe(III) secondary phases in those experiments. Akaganeite was the phase responsible for the passivation of the system in the experiments with Fe(III)-Cl-H+ solutions

  5. Uranium determination by spectrophotometry, in chloride solutions, using titanium (III) as reducer

    A simple method for determining uranium in uranium (VI) solutions with the presence of uranium (IV), iron (II), and titanium (IV) in chloridic solution is described. The method comprises in uranium (VI) reduction with titanium (III), acidity adjustment and uranium (IV) spectrophotometry in hydrochloric acid 2 M. (C.G.C.)

  6. TESTING OF 304L STAINLESS STEEL IN NITRIC ACID ENVIRONMENTS WITH FLUORIDES AND CHLORIDES

    Mickalonis, J.

    2010-10-04

    Impure radioactive material processed in nitric acid solutions resulted in the presence of chlorides in a dissolver fabricated from 304L stainless steel. An experimental program was conducted to study the effects of chloride in nitric acid/fluoride solutions on the corrosion of 304L stainless steel. The test variables included temperature (80, 95, and 110 C) and the concentrations of nitric acid (6, 12, and 14 M), fluoride (0.01, 0.1, and 0.2 M) and chloride (100, 350, 1000, and 2000 ppm). The impact of welding was also investigated. Results showed that the chloride concentration alone was not a dominant variable affecting the corrosion, but rather the interaction of chloride with fluoride significantly affected corrosion.

  7. Use of saturated sodium chloride solution as a tissue fixative

    A. Al-Saraj

    2010-01-01

    Full Text Available The present study was carried out to examine the capability of saturated sodium chloride solution as a fixative agent instead of formalin which is regarded as a carcinogenic material. For this purpose 3 rabbits were used and their livers, kidneys and spleens were exposed and removed. Neutral buffered formalin solution, saturated sodium chloride solution and distilled water were used as fixatives for specimens obtained from the first, second and third rabbits respectively. Routine histological technique was performed to prepare a stained histological sections for light microscopic examination. The result showed that the tissue sections which were obtained by using sodium chloride have the same histological features and without any artifacts when they compared with the results obtained using formalin fixation method. We conclude that the saturated sodium chloride solution can be used as a fixative agent in some circumstances when no any fixative agent is available.

  8. Electrodeposition of Zinc from Chloride Solution

    NAIK, Yanjerappa Arthoba; VENKATESHA, Thimmappa Venkatarangaiah

    2002-01-01

    The electroplating of zinc is carried out in the presence of 3,4,5-Trimethoxy benzaldehyde from a chloride bath. The bath constituents are optimized through Hull cell experiments. Operating parameters such as pH, temperature, and current density are also optimized. The current efficiency and throwing power are measured at different current densities. Polarization study is carried out under galvanostatic conditions. Corrosion resistance test indicated good protection of steel by the ...

  9. Modeling acid-gas generation from boiling chloride brines

    Zhang, Guoxiang; Spycher, Nicolas; Sonnenthal, Eric; Steefel, Carl

    2009-11-16

    This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes that are modeled include boiling of highly concentrated solutions, gas transport, and gas condensation accompanied by the dissociation of acid gases, causing low-pH condensate. Simple calculations are first carried out to evaluate condensate pH as a function of HCl gas fugacity and condensed water fraction for a vapor equilibrated with saturated calcium chloride brine at 50-150 C and 1 bar. The distillation of a calcium-chloride-dominated brine is then simulated with a reactive transport model using a brine composition representative of partially evaporated calcium-rich pore waters at Yucca Mountain. Results show a significant increase in boiling temperature from evaporative concentration, as well as low pH in condensates, particularly for dynamic systems where partial condensation takes place, which result in enrichment of HCl in condensates. These results are in qualitative agreement with experimental data from other studies. The combination of reactive transport with multicomponent brine chemistry to study evaporation, boiling, and the potential for acid gas generation at the proposed Yucca Mountain repository is seen as an improvement relative to previously applied simpler batch evaporation models. This approach allows the evaluation of thermal, hydrological, and chemical (THC) processes in a coupled manner, and modeling of settings much more relevant to actual field conditions than the distillation experiment considered. The actual and modeled distillation experiments do not represent

  10. Modeling acid-gas generation from boiling chloride brines

    This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes that are modeled include boiling of highly concentrated solutions, gas transport, and gas condensation accompanied by the dissociation of acid gases, causing low-pH condensate. Simple calculations are first carried out to evaluate condensate pH as a function of HCl gas fugacity and condensed water fraction for a vapor equilibrated with saturated calcium chloride brine at 50-150 C and 1 bar. The distillation of a calcium-chloride-dominated brine is then simulated with a reactive transport model using a brine composition representative of partially evaporated calcium-rich pore waters at Yucca Mountain. Results show a significant increase in boiling temperature from evaporative concentration, as well as low pH in condensates, particularly for dynamic systems where partial condensation takes place, which result in enrichment of HCl in condensates. These results are in qualitative agreement with experimental data from other studies. The combination of reactive transport with multicomponent brine chemistry to study evaporation, boiling, and the potential for acid gas generation at the proposed Yucca Mountain repository is seen as an improvement relative to previously applied simpler batch evaporation models. This approach allows the evaluation of thermal, hydrological, and chemical (THC) processes in a coupled manner, and modeling of settings much more relevant to actual field conditions than the distillation experiment considered. The actual and modeled distillation experiments do not represent

  11. Modeling acid-gas generation from boiling chloride brines

    Sonnenthal Eric

    2009-11-01

    Full Text Available Abstract Background This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes that are modeled include boiling of highly concentrated solutions, gas transport, and gas condensation accompanied by the dissociation of acid gases, causing low-pH condensate. Results Simple calculations are first carried out to evaluate condensate pH as a function of HCl gas fugacity and condensed water fraction for a vapor equilibrated with saturated calcium chloride brine at 50-150°C and 1 bar. The distillation of a calcium-chloride-dominated brine is then simulated with a reactive transport model using a brine composition representative of partially evaporated calcium-rich pore waters at Yucca Mountain. Results show a significant increase in boiling temperature from evaporative concentration, as well as low pH in condensates, particularly for dynamic systems where partial condensation takes place, which result in enrichment of HCl in condensates. These results are in qualitative agreement with experimental data from other studies. Conclusion The combination of reactive transport with multicomponent brine chemistry to study evaporation, boiling, and the potential for acid gas generation at the proposed Yucca Mountain repository is seen as an improvement relative to previously applied simpler batch evaporation models. This approach allows the evaluation of thermal, hydrological, and chemical (THC processes in a coupled manner, and modeling of settings much more relevant to actual field conditions than the distillation experiment considered. The actual

  12. Ions in hyaluronic acid solutions

    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.

  13. Platinum uptake from chloride solutions using biosorbents

    Mehmet Hakan Morcali; Bihter Zeytuncu; Onuralp Yucel

    2013-01-01

    Present work investigates platinum uptake from synthetically prepared, dilute platinum-bearing solutions using biomass residues, i.e. pistachio nut shell and rice husk, which are abundant in Turkey, and provides a comparison between these two biosorbents. Effects of the different uptake parameters, sorbent dosage, contact time, temperature and pH of solution on platinum uptake (%) were studied in detail on a batch sorption. Before the pistachio nut shell was activated, platinum uptake (%) was...

  14. The determination of hydroxide and carbonate in concentrated sodium chloride solutions

    Roolvink, W.B.; Bos, M.

    1980-01-01

    A computer method for the determination of carbonate and hydroxide in concentrated (2.89 M) sodium chloride solutions is described. The method is based on multiparametric curve-fitting and can also be applied to salts of dibasic acids with unknown equilibrium constants. The systematic error is not more than 1%. The titration and calculation takes less than 20 min.

  15. An experiment on multibubble sonoluminescence spectra in sodium chloride solution

    CHEN Zhan; XU JunFeng; HUANG Wei; CHEN WeiZhong; MIAO GuoQing

    2008-01-01

    We investigated experimentally the spectra of MBSL in sodium chloride water solution with krypton as dissolved gas. We observed and compared the spectra of hydroxyl ion at 310 nm and that of sodium atom at 589 nm. It has been found that under the same experimental condition, the intensity of sodium atom spectra is obviously higher than that of the hydroxyl ion spectra, and is more sensitive to the experimental condition. The krypton content, the concentration of sodium chloride solution, and the driving sound pressure obviously affect the spectra intensity in certain range.

  16. Pourbaix Diagrams for Copper in 5 m Chloride Solution

    Pourbaix diagrams for the copper in 5 molal chlorine at 5-100 deg C have been calculated. Predominance diagrams for dissolved copper containing species have also been calculated. Two different total concentrations of dissolved copper, 10-4 and 10-6 molal, have been used in the calculations. ChIoride is the predominating chlorine species in aqueous solutions. Therefore Pourbaix diagrams for chlorine can be used to discuss the effect of chloride solutions on the corrosion behavior of a metal. Presence of chloride increases the corrosion regions of copper at the expense of the immunity and passivity regions in the Pourbaix diagrams. Copper corrodes in 5 molal chloride by formation Of CuCl32- in acid and alkaline solutions. At higher potentials in acid solutions CuCl32- is oxidized to CuCl2(aq), which at increasing potentials can form CuCI+, Cu2+ or CuClO3+. Copper passivates by formation of Cu2O(cr), CuO(cr), or CUO2 3 Cu(OH)2(s). Cu2O(cr) does not form at [Cu(aq)]tot = 10-6 molal in 5 m C1-, which results in a corrosion area between the immunity and passivity areas. Copper at the anticipated repository potentials and pH corrodes at 100 deg C at [Cu(aq)]tot = 10-4 molal and at 80-100 deg C at [Cu(aq)]tot = 10-6 molal. Copper at the anticipated repository potentials and pH can corrode at 80 deg C at [Cu(aq)]tot = 10-4 molal and at 50 deg C at [Cu(aq)]tot = 10-6 molal. The bentonite clay and copper canisters in the deep repository can be considered as a 'closed' system from macroscopic point of view. The clay barrier limits both inward diffusion of oxygen and aggressive anions as well as outward diffusion of corrosion products from the canisters. Both diffusion phenomena will drive the corrosion potential into the immunity area of the Pourbaix diagram for copper. The corrosion will thereby stop by an automatic mechanism. However, this is only valid if no macro cracks occur in the clay. The auto-stop is valid for the initial, main and cooling phases. During a glacial

  17. Conductometric study of lanthanum chloride interaction with potash soaps of higher fatty acids

    Interaction of lanthanum chloride with potassium salts of higher aliphatic acids, containing from 10 to 16 carbon atoms, at room temperature in weakly acid media (pH=5.5) gives rise to neutral soaps of the La[CHsub(3)(CHsub(2))sub(n)COO]sub(3) composition, while in alkaline media (pH=8.0) base soaps of the LaOH[CHsub(3)(CHsub(2))sub(n)COO]sub(2) composition are formed. In acid solutions (pH=2.0) no interaction of lanthanum chloride with potassium soaps of the above carboxylic acids is observed

  18. Lead sulphate leaching by sodium chloride solution

    Conić Vesna T.; Pešovski Branka D.; Cvetkovski Vladimir B.; Stanojević-Šimšić Zdenka S.; Dragulović Suzana S.; Simonović Danijela B.; Dimitrijević Silvana B.

    2013-01-01

    Bioleaching treatment of complex multi-metallic Cu-Zn-Pb-Ag-Au mineral concentrates leds to the formation, besides easily soluble zinc and cooper sulphates, of hardly soluble lead (II) sulfate (PbSO4) sludge. To determine the leaching parameters of PbSO4 with NaCl in the bioleaching residue, lead sulphate solution was synthetically prepared. The effect of process parameters, namely NaCl concentration, solid:liquid phase ratio, processing time, temperature and Cl ions was examined. It wa...

  19. Platinum uptake from chloride solutions using biosorbents

    Mehmet Hakan Morcali

    2013-04-01

    Full Text Available Present work investigates platinum uptake from synthetically prepared, dilute platinum-bearing solutions using biomass residues, i.e. pistachio nut shell and rice husk, which are abundant in Turkey, and provides a comparison between these two biosorbents. Effects of the different uptake parameters, sorbent dosage, contact time, temperature and pH of solution on platinum uptake (% were studied in detail on a batch sorption. Before the pistachio nut shell was activated, platinum uptake (% was poor compared to the rice husk. However, after the pistachio nut shell was activated at 1000 °C under an argon atmosphere, the platinum uptake (% increased two-fold. The pistachio nut shell (original and activated and rice husk were shown to be better than commercially available activated carbon in terms of adsorption capacity. These two sorbents have also been characterized by FTIR and SEM. Adsorption equilibrium data best complied with the Langmuir isotherm model. Maximum adsorption capacities, Qmax, at 25 °C were found to be 38.31 and 42.02 mg.g- 1for the activated pistachio nut shell and rice husk, respectively. Thermodynamic calculations using the measured ∆H°, ∆S° and ∆G° values indicate that the uptake process was spontaneous and endothermic. The experimental data were shown to be fit the pseudo-second-order kinetic model.

  20. Metal dissolution and maximum stress during SCC process of ferritic (type 430) and austenitic (type 304 and type 316) stainless steels in acidic chloride solutions under constant applied stress

    By using a constant load method and inductive coupled plasma (ICP) spectrometer, the metal dissolution and maximum stress (σmair) of type 430 ferritic stainless, and type 304 and type 316 austenitic stainless steels during stress corrosion cracking (SCC) process were investigated under a constant applied stress condition in 0.82 kmol/m3 hydrochloric acid (HCl) and 0.82 kmol/m3 acidic chloride (pH 1.0) solutions. The σmair of the specimens interrupted at various elongations up to failure under the same constant applied stress condition was measured at room temperature and air atmosphere by using an Instron type tensile machine. The metal dissolution behaviour of the stainless steels changed at the transition time (tss) in the corrosion elongation curve; that is, the dissolution rate before tss was larger than that after tss. The σmair decreased gradually with increasing elongation, but showed a rapid small reduction at tss and then decreased with elongation with a sudden reduction around fracture. The results obtained were discussed in terms of the amount of metal ions per the number of cracks, selective dissolution, reduction in cross sectional area and so on

  1. Lead sulphate leaching by sodium chloride solution

    Conić Vesna T.

    2013-01-01

    Full Text Available Bioleaching treatment of complex multi-metallic Cu-Zn-Pb-Ag-Au mineral concentrates leds to the formation, besides easily soluble zinc and cooper sulphates, of hardly soluble lead (II sulfate (PbSO4 sludge. To determine the leaching parameters of PbSO4 with NaCl in the bioleaching residue, lead sulphate solution was synthetically prepared. The effect of process parameters, namely NaCl concentration, solid:liquid phase ratio, processing time, temperature and Cl ions was examined. It was found that 100% Pb by leaching can be achieved with NaCl concentration of 250 g/dm3, time 20 min, temperature 353 K and solid:liquid phase ratio =1:20.

  2. Intergranular Corrosion of 2024 Alloy in Chloride Solutions

    Augustin, Christel; Andrieu, Eric; Blanc, Christine; Mankowski, Georges; Delfosse, Jérôme

    2007-01-01

    Experiments were performed to determine the propagation kinetics of intergranular corrosion on 2024 aluminum alloy immersed in 1 and 3 M chloride solutions. Tests consisting of immersion in a corrosive solution followed by optical observations on sectioned samples were carried out. This method was found to be time consuming and led to a lack of reproducibility due to the random nature of the corrosion attacks. Another method proved to be more efficient; it consisted of measuring the load to f...

  3. Crevice Corrosion of 321 Stainless Steel in Sodium Chloride Solutions

    Electrochemical techniques have been applied to study the crevice corrosion behaviour of stabilized 321 stainless steel in both 0.5, 1 and 2 M sodium chloride solutions at 25 and 80 degree . This type of stainless steel enjoys a good corrosion resistance especially in the heat affected zone (Haz) of welds. In this investigation the crevice corrosion of 321 stainless steel was studied in both bulk solution environments as well as in chloride solutions simulating those formed inside crevices. A metal-to-nonmetal crevice assembly, in which disc type specimens were faced to a PTFE crevice former, is used for bulk solution tests. Crevice-free specimens of solutions formed inside crevices (known as the critical crevice solutions, CCS). Cyclic potentiodynamic technique was used in evaluating the electrochemical corrosion performance of the alloy in bulk (0.5 and 1 M Nacl) environment. This revealed that both chloride ion concentration and temperature have a marked effect on the electrochemical parameters generally used for the evaluation of the crevice corrosion susceptibility. This included the corrosion potential. E corr. The passivity breakdown potential, Eb, and the protection potential, E p

  4. Determination of cadmium, cobalt, manganese, copper, nickel, and chromium in concentrated solutions of calcium chloride by electrothermal atomic absorption spectrometry

    A procedure is developed for the direct determination of Cd, Co, Cr, Cu, Mn, and Ni in concentrated solutions of calcium chloride by electrothermal atomic absorption spectrometry. Ascorbic and oxalic acids and magnesium nitrate were examined as chemical modifiers. Oxalic acid was found to be the best modifier. Although an atomic absorption spectrometer with a background correction system of relatively low efficiency (deuterium lamp) was used, elements under study can be reliably determined in the presence of oxalic acid at concentrations of calcium chloride in the solution up to 6%. Because cadmium is evaporated before the major part of the given matrix, it can be determined without modifier

  5. Sodium chloride methanol solution spin-coating process for bulk-heterojunction polymer solar cells

    Liu, Tong-Fang; Hu, Yu-Feng; Deng, Zhen-Bo; Li, Xiong; Zhu, Li-Jie; Wang, Yue; Lv, Long-Feng; Wang, Tie-Ning; Lou, Zhi-Dong; Hou, Yan-Bing; Teng, Feng

    2016-08-01

    The sodium chloride methanol solution process is conducted on the conventional poly(3-hexylthiophene) (P3HT)/[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) polymer bulk heterojunction solar cells. The device exhibits a power conversion efficiency of up to 3.36%, 18% higher than that of the device without the solution process. The measurements of the active layer by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and ultraviolet photoelectron spectroscopy (UPS) indicate a slight phase separation in the vertical direction and a sodium chloride distributed island-like interface between the active layer and the cathode. The capacitance–voltage (C–V) and impedance spectroscopy measurements prove that the sodium chloride methanol process can reduce the electron injection barrier and improve the interfacial contact of polymer solar cells. Therefore, this one-step solution process not only optimizes the phase separation in the active layers but also forms a cathode buffer layer, which can enhance the generation, transport, and collection of photogenerated charge carriers in the device simultaneously. This work indicates that the inexpensive and non-toxic sodium chloride methanol solution process is an efficient one-step method for the low cost manufacturing of polymer solar cells. Project supported by the Fundamental Research Funds for the Central Universities, China (Grant No. 2014JBZ009) and the National Natural Science Foundation of China (Grant Nos. 61274063, 61377028, 61475014, and 61475017).

  6. Henry’s constant of carbon dioxide-aqueous deep eutectic solvent (choline chloride/ethylene glycol, choline chloride/glycerol, choline chloride/malonic acid) systems

    Highlights: • A new set of Henry’s constant for the system carbon dioxide-aqueous deep eutectic solvents were measured. • The DESs used were: ethaline, glyceline, and maline. • The measured data were reported as functions of temperature and composition. • The measured data were represented satisfactorily by the applied correlations. -- Abstract: In this study, we present a new set of Henry’s constant data for the system carbon dioxide-aqueous deep eutectic solvent (DES) (20 to 80 wt% DES) at T = (303.15, 308.15, and 313.15) K. The DESs used were choline chloride-based: ethaline (choline chloride/ethylene glycol), glyceline (choline chloride/glycerol), and maline (choline chloride/malonic acid). A differential Henry’s coefficient model was used to describe the behaviour of Henry’s constant, and correlate it with temperature and concentration of DES in the aqueous DES solution. The correlation was found satisfactory such that the proposed model can be used in engineering calculations with reasonable accuracy

  7. Production and mitigation of acid chlorides in geothermal steam

    Simonson, J.M.; Palmer, D.A.

    1995-06-01

    Measurements of the equilibrium distribution of relatively nonvolatile solutes between aqueous liquid and vapor phases have been made at temperatures to 350{degrees}C for HCl(aq) and chloride salts. These data are directly applicable to problems of corrosive-steam production in geothermal steam systems. Compositions of high-temperature brines which could produce steam having given concentrations of chlorides may be estimated at various boiling temperatures. Effects of mitigation methods (e.g., desuperheating) can be calculated based on liquid-vapor equilibrium constants and solute mass balances under vapor-saturation conditions.

  8. Adsorption of Tetradecylpyridinium Chloride on Aqueous Surfaces of Sodium Chloride Solutions

    Fujio, Katsuhiko; Hayashi, Koji; Suzuki, Maki

    2014-01-01

    Surface tension of aqueous NaCl solutions of tetradecylpyridinium chloride (TPC) has been measured by the drop weight method at different NaCl concentrations from 0 to 1.000 mol dm−3 at 25◦C. Surface excess densities of tetradecylpyridinium ion (TP+), Cl− and Na+ have been obtained as functions of TPC concentration at different NaCl concentrations by applying the Gibbs adsorption isotherm to the surface tension data below the critical micelle concentration (CMC) of TPC. Surface excess densiti...

  9. Adsorption of Dodecylpyridinium Chloride on Aqueous Surfaces of Sodium Chloride Solutions

    Fujio, Katsuhiko; TAKEUCHI, Kumiko; Suzuki, Maki

    2012-01-01

    Surface tension of aqueous NaCl solutions of dodecylpyridinium chloride (DPC) has been measured by the drop weight method at different NaCl concentrations from 0 to 1.000 mol dm-3 at 25℃. Applying the Gibbs adsorption isotherm to the surface tension data at DPC concentrations below the critical micelle concentration (CMC), surface excess densities of dodecylpyridinium ion (DP+), Cl- and Na+ have been obtained as functions of DPC concentration at different NaCl concentrations. Surface excess d...

  10. Soret diffusion processes in aqueous sodium chloride solutions

    Cygan, R.T.

    1985-01-01

    The mass transport of chemical species induced by a temperature gradient, commonly known as Soret diffusion, has been examined for the case of the sodium chloride and water system. The occurrence of significant thermal gradients in geological media, especially those associated with radioactive waste disposal sites, can produce a measurable flux of sodium chloride and therefore enrich the local solutions. Soret coefficients, or the ratio of thermal to isothermal mass transport factors, describe this rate of mass transfer and are necessary for evaluating certain nonequilibrium processes, such as the migration of fluid inclusions in rock salt. Experimental Soret coefficients for the NaCl-H/sub 2/O system were obtained by the use of a conductimetric thermal diffusion cell. This approach relies on monitoring the electrical conductivity change of two separate isothermal reservoirs which are maintained at different temperatures. The Soret cell is situated between the reservoirs and is comprised of an inert matrix of glass beads in order to minimize any solution convection. The utilization of this porous medium requires corrections for porosity and tortuosity. Measurements were made for 0.1 and 1.0 N NaCl solutions at mean temperatures of 40/sup 0/C and 50/sup 0/C with the mass transport induced by a thermal gradient of 2.6/sup 0/C/cm. The preliminary results indicate a Soret separation on the order of 1 to 2 percent with the attainment of a steady state in approximately 15 hours.

  11. Substituted sodium phenylanthranylates as inhibitors of corrosion in chloride solutions

    Kuznetsov, Yu.I.; Fialkov, Yu.A.; Popova, L.I.; Ehndel' man, E.S.; Kuznetsova, I.G. (AN SSSR, Moscow. Inst. Fizicheskoj Khimii)

    The efficiency of corrosion protection of armco iron, zinc (Ts-O) aluminium (AB 000) and its alloys (.D16 and AMG6) with sodium phenylanthranylate derivatives in chloride buffer solutions (pH 7.4-8.08) are investigated. It has been ascertained that the introduction of sodium phenylanthranylate into phenyl radical in m- and p-position relative to the amino group of electron-seeking substitutes improves protective properties of an inhibitor. The inhibiting effect of phenylanthranylates and its dependence on electron structure enchances in zinc-aluminium-iron series and decreases in case of transition from pure aluminium to its alloys.

  12. Effect of Organic Inhibitors on Chloride Corrosion of Steel Rebars in Alkaline Pore Solution

    Marina Cabrini

    2015-01-01

    Full Text Available The inhibition properties of aspartic and lactic acid salts are compared with nitrite ions with regard to their effect on critical chloride concentration. The tests were carried out on carbon steel specimens in simulated pore solutions with initial pH in the range of 12.6 to 13.8. The critical chloride concentrations were estimated through multiple specimen potentiostatic tests at potentials in the usual range for passive rebar in noncarbonated concrete structures. During tests, chloride ions were progressively added until all specimens showed localized attack, obtaining cumulative distribution curves reporting the fraction of corroded specimens as a function of chloride concentration. The presence of the organic inhibitors on the passivity film was detected by IR spectra. The results confirm that 0.1 M aspartate exhibits an inhibiting effect comparable with nitrite ions of the same concentration. Calcium lactate does not increase critical chloride concentration; however it appears to promote the formation of a massive scale, reducing the corrosion propagation.

  13. Copper electrodeposition from cuprous chloride solutions containing lead, zinc or iron ions

    M. Tchoumou; M. Roynette Ehics

    2005-01-01

    Cuprous chloride hydrochloric acid solutions were electrolysed in a two compartments cell without agitation for copper extraction. It is found that the current density affects the colour and the size of copper deposits. During electrodeposition of copper from cuprous solution in the presence of various concentrations of lead, zinc or iron ions at different current densities, it is observed that lead is codeposited with copper by increasing current density.In all experiments, the current efficiency for the copper deposition reaction fluctuates between 88.50% and 95.50%.

  14. Preparation of Pure Copper Powder from Acidic Copper Chloride Waste Etchant

    2008-01-01

    The method for the recycling of copper from copper chloride solution was developed. This process consists of extraction of copper, purification and particle size reduction. In the first step, reductive metal scraps were added to acidic copper chloride waste enchants produced in the PCB industry to obtain copper powder.Composition analysis showed that this powder contained impurities such as Fe, Ni, and water. So, drying and purification were carried out by using microwave and a centrifugal separator. Thereby the copper powder had a purity of higher than 99% and spherical form in morphology. The copper powder size was decreased by ball milling.

  15. Production of Reactor Fuel Oxides from Molten Chloride Salt Solutions

    Hanford Laboratories' work on reprocessing concepts for spent UO2-PuO2 fuels has led to the development of attractive, synthesis methods for several reactor fuel oxides possessing unique properties. By the use of molten chloride salt solutions as reaction media, it has been found possible to produce crystalline uranium and plutonium dioxides, and solid solutions of various oxide mixtures, at relatively low temperatures (500 to 750 deg. C). Exploratory work has indicated that these techniques may also be quite useful in the preparation of other nonmetallic fuel materials. Crystalline UO2 has been prepared by electrodeposition from molten chloride salt solutions of uranyl chloride. Material with oxygen-uranium ratios as low as 2.0006 and crystal densities as high as 10.92 (99.5% of the theoretical value) has been produced both in the laboratory and in 100-lb pilot-plant lots. This oxide appears well suited to such fuel element fabrication techniques as vibratory compaction. In carefully controlled laboratory-scale work, single crystals have been prepared weighing as much as 4 g. Conditions have also been worked out for the electro deposition of polycrystalline cylindrical UO2 rods. The intensive engineering studies have contributed markedly to the technology of containing and handling molten salts under chemical processing conditions and have provided a basis for preliminary cost studies which indicate that, with potential advances in technology, this method of preparation of dense UO2 may well compete economically with other established methods. Dense, black, finely divided crystals of UO2 with a bulk density greater than 6 g/cm3 have been produced by precipitation from molten salt media, under carefully selected conditions of salt composition, temperature, and sparge gas. It is anticipated that crystal growth can be controlled so as to give optimum particle-size distribution for fabrication of mixed oxide fuel elements. UO2-PuO2 and UO2-ThO2 solid solutions

  16. A chemical probe technique for the determination of reactive halogen species in aqueous solution: Part 2 – chloride solutions and mixed bromide/chloride solutions

    C. Anastasio

    2006-02-01

    Full Text Available Although reactive halogen species (X*=X●, ●X2−, X2 and HOX, where X=Br, Cl, or I are important environmental oxidants, relatively little is known about their kinetics in condensed phases such as seawater and sea-salt particles. Here we describe a new technique to determine reactive chlorine and bromine species in aqueous solutions by using allyl alcohol (CH2=CHCH2OH as a chemical probe. This probe is combined with competition kinetics in order to determine steady state concentrations of X*(aq. In some cases the technique also can be used to determine the rates of formation and lifetimes of X* in aqueous solution. In a companion paper we reported the results of our method development for aqueous solutions containing only bromide (Br−. In this paper, we discuss method development for solutions containing chloride (Cl− alone, and for solutions containing both bromide and chloride.

  17. Modeling acid-gas generation from boiling chloride brines

    Sonnenthal Eric; Spycher Nicolas; Zhang Guoxiang; Steefel Carl

    2009-01-01

    Abstract Background This study investigates the generation of HCl and other acid gases from boiling calcium chloride dominated waters at atmospheric pressure, primarily using numerical modeling. The main focus of this investigation relates to the long-term geologic disposal of nuclear waste at Yucca Mountain, Nevada, where pore waters around waste-emplacement tunnels are expected to undergo boiling and evaporative concentration as a result of the heat released by spent nuclear fuel. Processes...

  18. Corrosion of LY12 aluminum alloy in sodium chloride solution

    程英亮; 张昭; 曹发和; 李劲风; 张鉴清; 王建明; 曹楚南

    2003-01-01

    The corrosion behavior of LY12 alloy in sodium chloride solution and its electrochemical noise were reported. The development of the micro-pits on the alloy surface was monitored by scanning electron microscopy, scanning tunneling microscopy, and electrochemical noise method. All the measurements show that the corrosion of LY12 alloy can be divided into two stages: a very reactive initial stage and a relative constant stable stage. The initial stage is corresponded to the adsorption of Cl ions and its reaction with the oxide film and the dissolution of Mg containing particles. The stable stage is corresponded to the development of the micro-pits by the galvanic attack formed by Al-Fe-Cu-Mn containing particles and the matrix. The initial stage lasts about 2-3 h while the stable stage dominates the whole corrosion process.

  19. Passivity of Alloy 22 in Chloride and Fluoride Containing Solutions

    Carranza, R M; Rodr?guez, M A; Rebak, R B

    2005-06-07

    The aim of the present work was to study the passive behavior of Alloy 22 in chloride and fluoride containing solutions varying the heat treatment of the alloy, the halide concentration and the pH of the solution at 90 C. General corrosion behavior was studied using electrochemical techniques, which included open circuit potential monitoring over time, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements carried out at open circuit and at passive potentials. Corrosion rates obtained by EIS measurements after 24 h immersion were below 0.5 {micro}m/year. The corrosion rates were practically independent of the solution pH, short term corrosion potential (E{sub corr}), alloy heat treatment and halide ion nature and concentration. Polarization resistance (R{sub P}) values increased with open circuit potential and the polarization time at constant potential in 1M NaCl, pH 6, 90 C. This was attributed to an increase in the oxide film thickness and oxide film aging. Capacitance measurements indicated that passive oxide on Alloy 22 presented a double n-type/p-type semiconductor behavior in the passive potential range.

  20. Corrosion of alloy 22 in phosphate and chloride containing solutions

    Alloy C-22 is a Ni-based alloy (22% Cr, 13% Mo, 3% W y 3% Fe in weight per cent) that exhibits an excellent uniform and localized corrosion resistance due to its protective passive film. It was designed to resist the most aggressive environments for industrial applications. Alloy 22 is one of the candidates to be considered for the outer shell of the canister that would contain high level radioactive nuclear wastes. The effect of phosphate ion in chloride containing solutions at 90 C degrees was studied under aggressive conditions were this material might be susceptible to crevice corrosion. The electrolyte solution, which consisted of 1M NaCl and different phosphate concentrations (between 10-3M and 1M), was deoxygenated by bubbling with nitrogen. Electrochemical tests, electron microscope observations (SEM) and energy dispersive spectrometer analysis (EDS) were conducted. Crevice corrosion was not detected and the comparison of the potentiodynamic polarization tests showed an increase of the passivity range in phosphate containing solutions. The passive current value was 1 μA/cm2 approximately in all the tests that were performed in this work. The differences in composition of the anodic film formed on the samples suggest that phosphate is responsible for the increase of the passivity range by incorporation to the passive film. (author)

  1. Stress corrosion cracking of austenitic stainless steel in glycerol solution and chloride solution at elevated temperature

    Stress Corrosion Cracking (SCC) is an environmentally assisted failure caused by exposure to a corrodant while under a sustained tensile stress. SCC is most often rapid, unpredictable and catastrophic. Failure can occur in as little as a few hours or take years to happen. Most alloys are susceptible to SCC in one or more environments requiring careful consideration of alloy type in component design. In aqueous chloride environments austenitic stainless steels and many nickel based alloys are known to perform poorly. One of products Oleo chemical is glycerol solution. Glycerol solution contains chloride with concentration 50 ppm - 150 ppm. Austenitic stainless steel is usually used in distillation construction tank and pipe line of glycerol. Material AISI 304 will be failure in this glycerol solution with this concentration in 5 years. In production process, concentration of chloride in glycerol becomes more than 150 ppm at temperature 150 degree Celsius. The reason is that the experiment I conducted in high chloride with concentration such as 6000 ppm, 9000 ppm, and 12000 ppm. The stress corrosion cracking of the austenitic stainless steels of types AISI 304, 316 and 316L in glycerol solution at elevated temperature 150 degree Celsius is investigated as a function variation of chloride concentration, namely 50, 6000, 9000 and 12000 ppm using a constant load method with two kinds of initial tensile stress as 50 % and 70 % yield strength. The experiment uses a spring loaded fixture type and is based on ASTM G49 for experiment method, and E292 for geometry of specimen. Pitting corrosion occurs on the surface specimen until the stress level reaches the ultimate strength. Pitting corrosion attack and depletion occur on the surface as initiation of SCC failure as the stress reaches the ultimate strength. Failure has occurred in catastrophic brittle fracture type of transgranular. AISI 304 was more susceptible for all conditions. In chloride solution with concentration of

  2. Extraction of scandium from chloride solutions using phenolformaldehyde resol oligomer Yarrezin B

    Scandium extraction from acid chloride solutions using phenolformaldehyde resol oligomer Yarrezin B (YRB) was studied by the methods of UV, IR and X-ray photoelectron spectroscopy. In YRB molecules phenol nuclei are bound by methylene, o,o-dimethyleneamine and o,o-dimethyleneether bridges. It was ascertained that under the conditions scandium is extracted by chelate mechanism at metal/reagent ratio 1 : 1, besides, two chlorine atoms and two water molecules are incorporated into the complex. Coordination bond scandium-nitrogen in aminogroup is observed in the complex

  3. Extraction of scandium by benzoylantipyrine from chloride-perchlorate solutions

    Distribution of scandium complexes in case of extraction by benzoyl-4-antipyrine (BANT) in chloroform from aqueous chloride-perchlorate solutions, depending on extraction, perchlorate-ion and salting out agents concentration, was studied. It has been ascertained that scandium distribution factor is nearly 50 at NaClO4 and BANT concentrations equal to 2 and 0.1 mol/l respectively. Introduction of salting out agents (NaCl, CaCl2) and HCl at a constant content of NaClO4 (0.5 mol/l) increases noticeably scandium extraction. For 0.1 mol/l BANT solution in chloroform the extraction capacity in terms of scandium makes up 1.26 g/l. The optimal conditions for the element extraction have been found, the composition of the complex extracted has been ascertained (Sc:BANT:ClO4- = 1:3:3) and extraction mechanism has been suggested. Influence of interfering elements on scandium distribution factor was studied

  4. Corrosion of alloy C-22 in organic acid solutions

    Electrochemical studies such as cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS) were performed to determine the corrosion behavior of Alloy 22 (N06022) in 1M NaCl solutions at various pH values from acidic to neutral at 90 C degrees. All the tested material was wrought Mill Annealed (MA). Tests were also performed in NaCl solutions containing weak organic acids such as oxalic, acetic, citric and picric acids. Results show that the corrosion rate of Alloy 22 was significantly higher in solutions containing oxalic acid than in solutions of pure NaCl at the same pH. Citric and Picric acids showed a slightly higher corrosion rate, and Acetic acid maintained the corrosion rate of pure chloride solutions at the same pH. Organic acids revealed to be weak inhibitors for crevice corrosion. Higher concentration ratios, compared to nitrate ions, were needed to completely inhibit crevice corrosion in chloride solutions. Results are discussed considering acid dissociation constants, buffer capacity and complex formation constants of the different weak acids. (author)

  5. Synthesis and characterization of zinc chloride containing poly(acrylic acid) hydrogel by gamma irradiation

    In this study, the characterization of zinc chloride incorporated into a poly(acrylic acid) (PAAc) hydrogel prepared by gamma-ray irradiation was investigated. Zinc chloride powder with different concentrations was dissolved in the PAAc solution, and it was crosslinked with gamma-ray irradiation. The effects of various parameters such as zinc ion concentration and irradiation doses on characteristics of the hydrogel formed were investigated in detail for obtaining an antibacterial wound dressing. In addition, the gel content, pH-sensitive (pH 4 or 7) swelling ratio, and UV–vis absorption spectra of the zinc particles in the hydrogels were characterized. Moreover, antibacterial properties of these new materials against Staphylococcus aureus and Escherichia coli strains were observed on solid growth media. The antibacterial tests indicated that the zinc chloride containing PAAc hydrogels have good antibacterial activity. - Highlights: • The characterization of zinc chloride containing PAA hydrogel was investigated. • The gel content increased with an increase in absorbed dose up to 75 kGy. • Finally, the zinc chloride based hydrogels have an antibacterial activity

  6. An electrochemical study for corrosion inhibition of iron by some organic phosphonium chloride derivatives in acid media

    The inhibiting action of (chloromethyl) triphenyl phosphonium chloride (CTP), tetraphenyl phosphonum chloride (TP), triphenyl phosphine oxide (TPO), triphenyl (phenylmethyl) phosphonium chloride (TPM) and triphenyl phosphine (TPP) on the corrosion of iron in 1 M HCl solution was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Experimental results revealed that CTP, TP, TPO, and TPM act as inhibitors for iron in acid environments, while TPP is an accelerator. These compounds are mixed-type inhibitors and the inhibition efficiency increased with increasing concentrations. Equivalent circuits of the investigated systems are suggested

  7. Copper(I) mediated cross-coupling of amino acid derived organozinc reagents with acid chlorides

    Hjelmgaard, Thomas; Tanner, David Ackland

    2006-01-01

    This paper describes the development of a straightforward experimental protocol for copper-mediated cross-coupling of amino acid derived beta-amido-alkylzinc iodides 1 and 3 with a range of acid chlorides. The present method uses CuCN center dot 2LiCl as the copper source and for organozinc reagent...

  8. Kinetics of the oxidative hydroxylation of sodium hypophosphite in the presence of copper (II) chloride modified by humic (fulvo-) acid

    Zhaksyntay Kairbekov; Dina Akbayeva; Zhaniya Eshova; M. Bazhanovа

    2012-01-01

    It was established that in soft conditions (50-70oC, PO2 = 1 atm) sodium hypophosphite effectively is oxidized by oxygen in water solutions of copper(II) chloride  to give mainly a phosphorous acid. Humic (fulvo-) acid was extracted from brown coal of domestic deposit Kiyakty. For determination of optimum parameters of fulvo-acid extraction the laboratory experiments were carried out using the method of experiment planning. The kinetics, the intermediate and final products, optimal conditions...

  9. Stress Corrosion Cracking of an Austenitic Stainless Steel in Nitrite-Containing Chloride Solutions

    R. K. Singh Raman

    2014-12-01

    Full Text Available This article describes the susceptibility of 316L stainless steel to stress corrosion cracking (SCC in a nitrite-containing chloride solution. Slow strain rate testing (SSRT in 30 wt. % MgCl2 solution established SCC susceptibility, as evidenced by post-SSRT fractography. Addition of nitrite to the chloride solution, which is reported to have inhibitive influence on corrosion of stainless steels, was found to increase SCC susceptibility. The susceptibility was also found to increase with nitrite concentration. This behaviour is explained on the basis of the passivation and pitting characteristics of 316L steel in chloride solution.

  10. Thorium(IV) and radium(II) recovery from chloride solutions

    The studies on thorium(IV) and radium(II) removal by precipitation from process solutions of chloride processing of perovskite are reported. The solution acidity, reagent consumption, and temperature are studied for their effect on radium(II) coprecipitation with barium sulfate. It is found that radium(II) most completely precipitates at pH≥7. Under optimum purification conditions the level of α- and β-radioactivity goes down from ∼10000 to less than 75 Bq l-1. An optional technology is proposed which includes precipitation of hydroxides of iron(III), titanium(IV) or other elements at pH∼2.5, recovery of radium(II) on barium sulfate with simultaneous thorium(IV) precipitation (pH∼7), and preparation of rare earth(III) concentrate (pH∼9)

  11. Chloride content and pH value in the pore solution of concrete under carbonation

    Xiao-mei WAN; Folker H.WITTMANN; Tie-jun ZHAO; Hong FAN

    2013-01-01

    Chloride content and the pH value of the pore solution in the neighborhood of steel reinforcement are decisive parameters for initiation and rate of corrosion.The pore solution of cement mortar and hardened cement paste has been expressed from the pore space by high pressure in the investigation.The influence of the water-cement ratio,age,and addition of chloride to the fresh mix on chloride content in the pore solution has been determined by ion chromatography.At the same time the pH value of the pore solution has been determined.The dissolved chloride content decreases with increase in the water-cement ratio.The amount of bound chloride increases with time,but it decreases with decreasing content of dissolved chloride in the pore solution.A significant influence of carbonation on the dissolved chloride content of the pore solution has been observed.With complete carbonation,the dissolved chloride content in cement mortar and hardened cement paste increases by a factor between 2 and 12.The bound chloride decreases by 27%-54%.As expected,the pH value decreases from around 13.2 to as low as 8.0 due to carbonation.It can be concluded that carbonation not only lowers the pH value but liberates bound chloride.This is one obvious reason why the combined action of chloride penetration and carbonation accelerates steel corrosion and shortens the service life of reinforced concrete structures.

  12. A review of CANMET's acid chloride leaching of uranium ores

    Conventional sulphuric acid leach processing of uranium ore is technically and economically viable but presents some environmental concerns because almost all of the radium and the sulphides, especially pyrite (an acid generating mineral), present in the ore report to the tailing disposal sites. In order to obtain leach tailings with a radium (226) content of 20-25 pCi/g solids and essentially free of pyrite, an alternative HCl leach process has been developed. Hydrochloric acid leaching of low-grade pyritic uranium ore (e.g. Elliot Lake U-ore) followed by flotation for pyrite removal from the final leach residue yielded tailings essentially free of pyrite and radionuclides, the radium level in the tailings being in the range of 25-30 pCi g-1 solids. Acid chloride leaching of Midwest Lake uranium ore, under various conditions (e.g., HCl, HCl-CaCl2-O2 pressure, HCL-FeCl3) provided high extraction of U, Ni, As and Ra and tailings with radium levels above 177 pCi g-1 solids. However HCl leaching of the radium preleached Midwest Lake uranium ore provided the best extraction of U(>99%), Ni(88%), As(90%) and Ra (98%) and the tailings with only 108 pCi g-1 solids radium. Of course, out of these 108 pCi/g solids, at least 66 pCi/g solids were tied up with the residual uranium (0.02%) in the tailings, and the remaining radium (42 pCi/g solids) present as sparingly soluble radium salt/salts (e.g., RaS04). The acid chloride leaching process for uranium ore has definite technological and environmental merits but presently compares unfavourably both in capital and operating costs with the conventional sulphuric acid leach process. However, the economics of the HCl leach process could become viable when the costs of removing the radium (226) and the sulphides (i.e., the acid generating minerals) from sulphuric acid leach tailings are taken into consideration

  13. Uranium(VI) extraction from chloride solution with benzyloctadecyldimethyl ammonium chloride (BODMAC) in a liquid membrane process

    The recovery of uranium(VI) from chloride solution using a liquid emulsion membrane (LEM) technique was studied. The emulsion is constituted by the quaternary salt of benzyloctadecyldimethyl ammonium chloride (BODMAC, R4NCl) as a carrier, kerosene as organic diluent, Span 80 as emulsifying agent and 0.5 mol/l Na2CO3 as stripping phase. The important variables affecting the LEM permeation process such as the concentrations of extractant, internal strip phase, types of organic diluent, and the presence of magnesium chloride or magnesium sulfate were investigated. It was found that, at a given condition, the maximum extraction rate of uranium(VI) reached 80%. The emulsion was stable at low pH in the presence of certain amounts of electrolytes such as NaCl and MgCl2. (author)

  14. Enthalpic interactions of N-glycylglycine with xylitol in aqueous sodium chloride and potassium chloride solutions at T = 298.15 K

    The mixing enthalpies of N-glycylglycine with xylitol and their respective enthalpies of dilution in aqueous sodium chloride and potassium chloride solutions have been determined by using flow-mix isothermal microcalorimetry at the temperature of 298.15 K. These experimental results have been used to determine the heterotactic enthalpic interaction coefficients (hxy, hxxy, and hxyy) according to the McMillan-Mayer theory. It has been found that the heterotactic enthalpic pairwise interaction coefficients hxy between N-glycylglycine and xylitol in aqueous sodium chloride and potassium chloride solutions are negative and become less negative with an increase in the molality of sodium chloride or potassium chloride. The results are discussed in terms of solute-solute and solute-solvent interactions.

  15. Enthalpic interactions of N-glycylglycine with xylitol in aqueous sodium chloride and potassium chloride solutions at T = 298.15 K

    Liu Min, E-mail: panpanliumin@163.co [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Wang Lili [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Zhu Lanying [College of Life Science and Bioengineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Li Hui; Sun Dezhi; Di Youying; Li Linwei [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China)

    2010-07-15

    The mixing enthalpies of N-glycylglycine with xylitol and their respective enthalpies of dilution in aqueous sodium chloride and potassium chloride solutions have been determined by using flow-mix isothermal microcalorimetry at the temperature of 298.15 K. These experimental results have been used to determine the heterotactic enthalpic interaction coefficients (h{sub xy}, h{sub xxy}, and h{sub xyy}) according to the McMillan-Mayer theory. It has been found that the heterotactic enthalpic pairwise interaction coefficients h{sub xy} between N-glycylglycine and xylitol in aqueous sodium chloride and potassium chloride solutions are negative and become less negative with an increase in the molality of sodium chloride or potassium chloride. The results are discussed in terms of solute-solute and solute-solvent interactions.

  16. Effect of pH and chloride on the micro-mechanism of pitting corrosion for high strength pipeline steel in aerated NaCl solutions

    Highlights: • Pitting behavior of X80 steel in aerated NaCl solutions is studied systematically. • Unique large pit morphology is observed in neutral/acidic NaCl solutions. • In low pH solutions, pit will propagate in the horizontal direction, leading to the shallow shape of pitting morphology; in high pH solutions, the pit sizes are much smaller. • Film growth, which is dependent on the pH and chloride concentration, has great influence on the cathodic reaction by affecting oxygen diffusion process. - Abstract: The pitting corrosion mechanism of high strength pipeline steel in aerated NaCl solutions with different pH and chloride content was investigated, using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). The pitting behavior in alkaline solutions was found to be significantly different from that in neutral and acidic solutions. Electrochemical results and SEM images indicate that the product film formed on the steel surface results in different corrosion behavior in an alkaline solution. SEM images show that pH and chloride concentration in the bulk solution have a great influence on the pitting morphology. Unique large pit morphology due to corrosion in neutral/acidic solutions with 0.05 mol/L NaCl was observed. The relationship between solution pH and the effect of chloride concentration is also discussed

  17. Effect of pH and chloride on the micro-mechanism of pitting corrosion for high strength pipeline steel in aerated NaCl solutions

    Wang, Yafei; Cheng, Guangxu, E-mail: gxcheng@mail.xjtu.edu.cn; Wu, Wei; Qiao, Qiao; Li, Yun; Li, Xiufeng

    2015-09-15

    Highlights: • Pitting behavior of X80 steel in aerated NaCl solutions is studied systematically. • Unique large pit morphology is observed in neutral/acidic NaCl solutions. • In low pH solutions, pit will propagate in the horizontal direction, leading to the shallow shape of pitting morphology; in high pH solutions, the pit sizes are much smaller. • Film growth, which is dependent on the pH and chloride concentration, has great influence on the cathodic reaction by affecting oxygen diffusion process. - Abstract: The pitting corrosion mechanism of high strength pipeline steel in aerated NaCl solutions with different pH and chloride content was investigated, using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). The pitting behavior in alkaline solutions was found to be significantly different from that in neutral and acidic solutions. Electrochemical results and SEM images indicate that the product film formed on the steel surface results in different corrosion behavior in an alkaline solution. SEM images show that pH and chloride concentration in the bulk solution have a great influence on the pitting morphology. Unique large pit morphology due to corrosion in neutral/acidic solutions with 0.05 mol/L NaCl was observed. The relationship between solution pH and the effect of chloride concentration is also discussed.

  18. Mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions

    熊良宵; 虞利军

    2015-01-01

    To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elastic modulus, the mass variation, and the compressive strength of cement mortar increase first, and then decrease with increasing erosion time in sodium sulfate and sodium chloride solutions. The relative dynamic elastic moduli and the compressive strengths of cement mortars with water/cement ratios of 0.55 and 0.65 in sodium sulfate solution are lower than those in sodium chloride solution with the same concentration at the 420th day of immersion. The compressive strength of cement mortar with water/cement ratio of 0.65 is more sensitive to strain rate than that with water/cement ratio of 0.55. In addition, the strain-rate sensitivity of compressive strength of cement mortar will increase under attacks of sodium sulfate or sodium chloride solution.

  19. Effect of gamma radiation on glucose and sodium chloride solutions for injection

    Irradiation of 40% glucose solution with 0.5-4.0 Mrads di not affect the detoxicating properties of glucose or its ability to raise blood sugar levels. Such doses had no effect on the toxicological properties of 40% glucose solution and on 0.9% sodium chloride solution. The biological and physicochemical properties of 40% solution and 0.9% sodium chloride solutions irradiated with sterilizing doses showed no significant alterations during storage for one and three years, respectively. It is concluded that the solutions studied may be sterilized by radiation. (auth.)

  20. Alcohol solutions of triphenyl-tetrazolium chloride as high-dose radiochromic dosimeters

    The radiolytic reduction of colorless tetrazolium salts in aqueous solution to the highly colored formazan dye is a well-known acid-forming radiation chemical reaction. Radiochromic thin films and three-dimensional hydrocolloid gels have been used for imaging and mapping absorbed dose distributions. The high solubility of 2,3,5-triphenyl-tetrazolium chloride (TTC) in alcohols provides a useful liquid dosimeter (45 nM TTC in aerated ethanol) and shows a linear response of absorbance increase (λmax = 480 nm) with dose over the range 1-16 kGy. The linear molar absorption coefficient (εm) for the formazan at the absorption peak is 1.5 x 103 m2 mol-1, and the radiation chemical yield for the above solution is G (formazan) = 0.014 μmol J-1. The irradiation temperature coefficient is about 0.8 percent per degree Celsius rise in temperature over the temperature range 0-30oC but is much larger between 30oC and 60oC. The unirradiated and irradiated solutions are stable over at least five days storage at normal laboratory temperature in the dark, but when stored in daylight at elevated temperature, the unirradiated solution in sealed amber glass ampoules undergoes slow photolytic dye formation, and the irradiated solution experiences initial fading and subsequent reversal (photochromism) when exposed to direct sunlight. (author)

  1. Potentiometric titration of uranium reduced by chromic salts in chloridic solutions

    The utilization of chromic salts for reducing the uranium (VI) from chloridic solutions, for potentiometric dosage is described. This method is used in the range of 0,002 to 1,0 M of uranium. (C.G.C.)

  2. Electrodeposition of cerium from aqueous cerous chloride solutions

    Cerium was plated as a grey, metallic, adherent deposit from aqueous cerous chloride baths containing certain organic addition agents. The cathodic current efficiency was determined for each case. Chemical analysis indicates that the purity of the metal is better than 99.0 per cent. (author). 7 refs

  3. Enthalpic Pair Interaction of Rubidium Chloride with α-Amino Acid in Water at 298.15K

    胡满成; 杨茜; 蒋育澄; 夏树屏

    2005-01-01

    The mixing enthalpies of aqueous heavy rare alkali metal chloride RbC1 solutions with aqueous α-amino acid (Loglycine, L-alanine and α-aminobutyric acid) solutions, as well as the dilution enthalpies of RbC1 and α-amino acid solutions in pure water had been measured at 298.15K. The transfer enthalpies of RbCI from pure water to aqueous α-amino acid solutions could be obtained from these data. The enthalpic pair interaction parameters of RbC1 with α-amino acid in water have been evaluated according to the McMillan-Mayer theory and discussed in terms of the electrostatic interaction, structure interaction and Savage-wood group additivity mode.

  4. The isolation of beryllium and mercury from lithium chloride solution by means of gas extraction

    The possibility and optimal conditions of beryllium and mercury extraction using acetylacetone (HAA) from lithium chloride solution by argon blowing through the solution are determined. Dependences of extraction degrees and distribution coefficients on different parameters of liquid phase: initial pH value, lithium chloride concentration and initial content of HAA, are presented. The degree of beryllium extraction reaches the maximum at liquid phase pH of 4.4-5.25 and concentration of lithium chloride of 8.5 mol/l. Distribution coefficient changes in inverse proportion to the extraction degree

  5. Chemical characterization of a potassium hydroxyapatite prepared by soaking in potassium chloride and carbonate solutions.

    Nordström, E G; Karlsson, K H

    1992-01-01

    A potassium-doped synthetic apatite was prepared by soaking hydroxyapatite in potassium carbonate and potassium chloride solutions. The hydroxyapatite was prepared by firing slip cast ceramic bodies in vacuum at 1100 degrees C. The conical ceramic samples and a crushed material of this were soaked in carbonate and chloride solutions for 2, 4, 6, and 8 weeks. Potassium, calcium, and phosphate were determined by direct current plasma emission spectroscopy. The carbonate content was determined by thermogravimetric analysis and chloride titrimetrically. After 2 weeks, one potassium ion substituted one calcium ion when soaked in a carbonate solution. When soaked in the chloride solution substitution occurred to the same extent. At phosphate sites the substitution of phosphate for carbonate occurred at one sixth of the sites after 2 weeks. Chloride incorporated one half of the OH-sites after 2 weeks. After 4 weeks about one chloride ion was found in the apatite, and after 6 weeks one and a half of the OH-sites were occupied by chloride ions. PMID:1483120

  6. Crevice corrosion of alloy 22 in fluoride and chloride containing solutions

    Alloy 22 (N06022) is highly resistant to localized corrosion. Alloy 22 may be susceptible to crevice corrosion in pure chloride (Cl-) solutions under aggressive environmental conditions. The effect of the fluoride (F-) on the susceptibility to crevice corrosion induced by chloride ions is still not well established. The objective of the present work was to explore the crevice corrosion resistance of this alloy to different mixtures of fluorides and chlorides. Cyclic potentiodynamic polarization (CPP) tests were conducted in deaerated aqueous solutions of pure halide ions and also in different mixtures of chloride and fluoride at 90 C degrees and pH 6. The range of chloride concentration [Cl-] was 0.001 M ≤ [Cl-] ≤ 1 M and the range of molar fluoride to chloride ratio [F-]/[Cl-] was 0.1≤ [F-]/[Cl-] ≤ 10. Results showed that Alloy 22 was susceptible to crevice corrosion in all the pure chloride solutions but not in the pure fluoride solutions. A molar ratio [F-]/[Cl-] ranging from 5 to 10 was required for the inhibition of crevice corrosion to be complete in the halide mixtures. A moderate or nil inhibitive effect was observed for molar ratios [F-]/[Cl-] < 5. (author)

  7. Cyclic stress effect on stress corrosion cracking of duplex stainless steel in chloride and caustic solutions

    Yang, Di

    Duplex stainless steel (DSS) is a dual-phase material with approximately equal volume amount of austenite and ferrite. It has both great mechanical properties (good ductility and high tensile/fatigue strength) and excellent corrosion resistance due to the mixture of the two phases. Cyclic loadings with high stress level and low frequency are experienced by many structures. However, the existing study on corrosion fatigue (CF) study of various metallic materials has mainly concentrated on relatively high frequency range. No systematic study has been done to understand the ultra-low frequency (˜10-5 Hz) cyclic loading effect on stress corrosion cracking (SCC) of DSSs. In this study, the ultra-low frequency cyclic loading effect on SCC of DSS 2205 was studied in acidified sodium chloride and caustic white liquor (WL) solutions. The research work focused on the environmental effect on SCC of DSS 2205, the cyclic stress effect on strain accumulation behavior of DSS 2205, and the combined environmental and cyclic stress effect on the stress corrosion crack initiation of DSS 2205 in the above environments. Potentiodynamic polarization tests were performed to investigate the electrochemical behavior of DSS 2205 in acidic NaCl solution. Series of slow strain rate tests (SSRTs) at different applied potential values were conducted to reveal the optimum applied potential value for SCC to happen. Room temperature static and cyclic creep tests were performed in air to illustrate the strain accumulation effect of cyclic stresses. Test results showed that cyclic loading could enhance strain accumulation in DSS 2205 compared to static loading. Moreover, the strain accumulation behavior of DSS 2205 was found to be controlled by the two phases of DSS 2205 with different crystal structures. The B.C.C. ferrite phase enhanced strain accumulation due to extensive cross-slips of the dislocations, whereas the F.C.C. austenite phase resisted strain accumulation due to cyclic strain

  8. Effect of different ions on the anodic behaviour of alloy 800 chloride solutions at high temperature

    The anodic behaviour and passivity breakdown of alloy 800 in sodium bicarbonate and sodium phosphate aqueous solutions were studied in the temperature range from 100 degrees C to 280 degrees C by means of electrochemical techniques. The effect of phosphate or bicarbonate additions on the pitting susceptibility and pitting morphology of the alloy in chloride solutions was also examined. Experiments were performed in the following solutions: 0.1M NaHCO3, at 100 degrees C, 200 degrees C, 280 degrees C; 0.06M NaH2PO4 + 0.04M Na2HPO4, at 100 degrees C, 200 degrees C and 280 degrees C, and 0.1M NaCl with different additions of bicarbonate ion (0.02M, 0.05M and 0.1M) and phosphate ion (0.01M, 0.05M and 0.1M) at 100 degrees C and 280 degrees C. The anodic polarization curves of alloy 800 in deaerated 0.1M NaHCO3 and 0.06M NaH2PO4 + 0.04M Na2HPO4 solutions exhibited a similar shape at all the tested temperatures. No localized or generalized corrosion was detected on the metallic surface after polarization. The results obtained in chloride plus bicarbonate and chloride plus phosphate mixtures showed that the pitting potential of alloy 800 in chloride solutions was increased by the presence of bicarbonate or phosphate ions. In those solutions where the inhibitor concentration in the mixture is equal or higher than the chloride concentration , the behaviour of the alloy is similar to the one observed in the absence of chlorides. Changes in pitting morphology were found in phosphate containing solutions, while the pits found in bicarbonate containing solutions were similar to those formed in pure chloride solutions. (author). 3 refs., 4 figs

  9. Concentration of rhenium from dilute sodium chloride solutions

    DRAGOLJUB M. LUKIC

    2008-03-01

    Full Text Available The conditions for the desorption of rhenium from the anion exchange resin Dowex 1-x8 by HNO3, HCl, H2SO4 and NaOH were determined. The solution (5.0´10-3 mol dm-3 Re in 0.15 mol dm-3 NaCl was passed through a column containing 0.10 g of the resin. The total sorbed amount of rhenium was 0.20 g/g of the resin. It was then eluted by the corresponding eluent in the concentration range up to about 3.0 mol dm-3. The highest elution efficiency and the most favourable elution profile were found with 3.0 mol dm-3 HNO3. Over 77 % of the sorbed rhenium was found in the first 5 ml of the eluate. Practically all the rhenium was recovered with 20 ml of the acid. Under the given experimental conditions, HCl and H2SO4 were less favourable while NaOH was not applicable, due to very low efficiency of rhenium elution.

  10. Kinetics of the oxidative hydroxylation of tetraphosphorus in the presence of copper(II) chloride modified by humic (fulvo-) acid

    Zhaksyntay Kairbekov; Dina Akbayeva; Zh. Eshova

    2012-01-01

    It was established that in mild conditions (50-70 oC, РО2= 1 atm) white phosphorus effectively is oxidized by oxygen in water-toluene solutions of copper(II) chloride modified by humic (fulvo-) acid to give mainly phosphoric acid. Humic (fulvo-) acid was extracted from brown coal of domestic deposit Kiyakty. For determination of optimum parameters of fulvo-acid extraction the laboratory experiments were carried out using the method of experiment planning. The kinetics, intermediate and final ...

  11. Ions in hyaluronic acid solutions

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

    2009-01-01

    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...

  12. Analysis of PWR auxiliary coolant: determination of chloride in borax/nitrite solution by known addition - known dilution potentiometry

    Chloride concentrations of 75-250 μg 1-1 have been determined in simulated PWR auxiliary coolant containing 1000 mg l-1 each of sodium tetraborate and sodium nitrite. The effects of the two main components of the coolant solution on a variety of chloride-selective electrodes have been studied. Sodium tetraborate posed no problem except through its effect on the pH, which is easily adjusted. Such high concentrations of nitrite, however, caused significant deviations in e.m.f. for all the electrodes and marked tarnishing of the electroactive membrane after only one or two measurements. Sulphamic acid was selected as the best means of removing nitrite and silver chloride electrodes were preferred over mercury(I) chloride electrodes because of their greater robustness in the conditions. At these chloride concentrations, the electrodes are operating in their non-Nernstian response regions and direct potentiometry has poor precision, even if standards could be successfully matched to samples containing such high concentrations of background material. Known addition - known dilution potentiometry was adopted, with internal calibration for both slope factor and standard potential. (author)

  13. Corrosion Inhibition of Carbon Steel in Chloride and Sulfate Solutions

    Amr Ahmed Elsayed

    2016-02-01

    Full Text Available Corrosion is a major problem in industry and in infrastructure; a huge sum of expenditure every year is spent on preventing, retarding, and repairing its damages. This work studies the engineering of an inhibitor for carbon steel metal used in the cooling systems containing high concentration of chloride and sulfate ions. For this purpose, the synergy between the dichromate, molybdate and nitrite inhibitors is examined and optimized to the best results. Moreover, care was taken that the proposed inhibitor is compliant with the environmental laws and regulations.

  14. Interaction between lactose and cadmium chloride in aqueous solutions as seen by diffusion coefficients measurements

    Highlights: ► Diffusion coefficients of aqueous systems containing lactose and cadmium chloride. ► Influence of the lactose on the diffusion of cadmium chloride. ► Interactions between Cd2+ and lactose. -- Abstract: Diffusion coefficients of an aqueous system containing cadmium chloride 0.100 mol · dm−3 and lactose at different concentrations at 25 °C have been measured, using a conductimetric cell and an automatic apparatus to follow diffusion. The cell relies on an open-ended capillary method and a conductimetric technique is used to follow the diffusion process by measuring the resistance of a solution inside the capillaries, at recorded times. From these results and by ab initio calculations, it was possible to obtain a better understanding of the effect of lactose on transport of cadmium chloride in aqueous solutions

  15. Fabrication and Performance of All-Solid-State Chloride Sensors in Synthetic Concrete Pore Solutions

    Gao, Xiaojian; Zhang, Jian; Yang, Yingzi; Deng, Hongwei

    2010-01-01

    One type of all-solid-state chloride sensor was fabricated using a MnO2 electrode and a Ag/AgCl electrode. The potentiometric response of the sensor to chloride in synthetic concrete pore solutions was systematically studied, and the polarization performance was also evaluated. The results show a good linear relationship between the potential reading of the sensor and the logarithm of chloride activity (concentration ranges from 0.05 to 5.0 M), and the potential value remains stable with incr...

  16. Redox flow batteries based on supporting solutions containing chloride

    Li, Liyu; Kim, Soowhan; Yang, Zhenguo; Wang, Wei; Nie, Zimin; Chen, Baowei; Zhang, Jianlu; Xia, Guanguang

    2015-07-07

    Redox flow battery systems having a supporting solution that contains Cl.sup.- ions can exhibit improved performance and characteristics. Furthermore, a supporting solution having mixed SO.sub.4.sup.2- and Cl.sup.- ions can provide increased energy density and improved stability and solubility of one or more of the ionic species in the catholyte and/or anolyte. According to one example, a vanadium-based redox flow battery system is characterized by an anolyte having V.sup.2+ and V.sup.3+ in a supporting solution and a catholyte having V.sup.4+ and V.sup.5+ in a supporting solution. The supporting solution can contain Cl.sup.- ions or a mixture of SO.sub.4.sup.2- and Cl.sup.- ions.

  17. Redox flow batteries based on supporting solutions containing chloride

    Li, Liyu; Kim, Soowhan; Yang, Zhenguo; Wang, Wei; Zhang, Jianlu; Chen, Baowei; Nie, Zimin; Xia, Guanguang

    2014-01-14

    Redox flow battery systems having a supporting solution that contains Cl.sup.- ions can exhibit improved performance and characteristics. Furthermore, a supporting solution having mixed SO.sub.4.sup.2- and Cl.sup.- ions can provide increased energy density and improved stability and solubility of one or more of the ionic species in the catholyte and/or anolyte. According to one example, a vanadium-based redox flow battery system is characterized by an anolyte having V.sup.2+ and V.sup.3+ in a supporting solution and a catholyte having V.sup.4+ and V.sup.5+ in a supporting solution. The supporting solution can contain Cl.sup.- ions or a mixture of SO.sub.4.sup.2- and Cl.sup.- ions.

  18. Redox flow batteries based on supporting solutions containing chloride

    Li, Liyu; Kim, Soowhan; Yang, Zhenguo; Wang, Wei; Nie, Zimin; Chen, Baowei; Zhang, Jianlu; Xia, Guanguang

    2015-09-01

    Redox flow battery systems having a supporting solution that contains Cl.sup.- ions can exhibit improved performance and characteristics. Furthermore, a supporting solution having mixed SO.sub.4.sup.2- and Cl.sup.- ions can provide increased energy density and improved stability and solubility of one or more of the ionic species in the catholyte and/or anolyte. According to one example, a vanadium-based redox flow battery system is characterized by an anolyte having V.sup.2+ and V.sup.3+ in a supporting solution and a catholyte having V.sup.4+ and V.sup.5+ in a supporting solution. The supporting solution can contain Cl.sup.- ions or a mixture of SO.sub.4.sup.2- and Cl.sup.- ions.

  19. Iron-Catalyzed Acylation of Polyfunctionalized Aryl- and Benzylzinc Halides with Acid Chlorides.

    Benischke, Andreas D; Leroux, Marcel; Knoll, Irina; Knochel, Paul

    2016-08-01

    FeCl2 (5 mol %) catalyzes a smooth and convenient acylation of functionalized arylzinc halides at 50 °C (2-4 h) and benzylic zinc chlorides at 25 °C (0.5-4 h) with a variety of acid chlorides leading to polyfunctionalized diaryl and aryl heteroaryl ketones. PMID:27457108

  20. Zinc chloride aqueous solution as a solvent for starch.

    Lin, Meiying; Shang, Xiaoqin; Liu, Peng; Xie, Fengwei; Chen, Xiaodong; Sun, Yongyi; Wan, Junyan

    2016-01-20

    It is important to obtain starch-based homogeneous systems for starch modification. Regarding this, an important key point is to find cheap, low-cost and low-toxicity solvents to allow complete dissolution of starch and its easy regeneration. This study reveals that a ZnCl2 aqueous solution is a good non-derivatizing solvent for starch at 50 °C, and can completely dissolve starch granules. The possible formation of a "zinc-starch complex" might account for the dissolution; and the degradation of starch, which was caused by the H(+) inZnCl2 aqueous solution, could not contribute to full dissolution. From polarized light microscopic observation combined with the solution turbidity results, it was found that the lowest ZnCl2 concentration for full dissolution was 29.6 wt.% at 50 °C, with the dissolving time being 4h. Using Fourier-transform infrared (FTIR), solid state (13)C nuclear magnetic resonance (NMR), and X-ray diffraction (XRD), it was revealed that ZnCl2 solution had no chemical reaction with starch glucosides, but only weakened starch hydrogen bonding and converted the crystalline regions to amorphous regions. In addition, as shown by intrinsic viscosity and thermogravimetric analysis (TGA), ZnCl2 solution caused degradation of starch macromolecules, which was more serious with a higher concentration of ZnCl2 solution. PMID:26572355

  1. Fabrication and Performance of All-Solid-State Chloride Sensors in Synthetic Concrete Pore Solutions

    Hongwei Deng

    2010-11-01

    Full Text Available One type of all-solid-state chloride sensor was fabricated using a MnO2 electrode and a Ag/AgCl electrode. The potentiometric response of the sensor to chloride in synthetic concrete pore solutions was systematically studied, and the polarization performance was also evaluated. The results show a good linear relationship between the potential reading of the sensor and the logarithm of chloride activity (concentration ranges from 0.05 to 5.0 M, and the potential value remains stable with increasing immersion time. The existence of K+, Ca2+, Na+ and SO42− ions have little influence on the potentiometric response of the sensor to chloride, but the pH has a significant influence on the potential value of the sensor at low chloride concentration. The potential reading of the sensor increases linearly with the solution temperature over the range from 5 to 45 °C. Meanwhile, an excellent polarization behavior is proven by galvanostatic and potentiodynamic tests. All of the results reveal that the developed sensor has a great potential for monitoring chloride ions in concrete environments.

  2. Fabrication and performance of all-solid-state chloride sensors in synthetic concrete pore solutions.

    Gao, Xiaojian; Zhang, Jian; Yang, Yingzi; Deng, Hongwei

    2010-01-01

    One type of all-solid-state chloride sensor was fabricated using a MnO(2) electrode and a Ag/AgCl electrode. The potentiometric response of the sensor to chloride in synthetic concrete pore solutions was systematically studied, and the polarization performance was also evaluated. The results show a good linear relationship between the potential reading of the sensor and the logarithm of chloride activity (concentration ranges from 0.05 to 5.0 M), and the potential value remains stable with increasing immersion time. The existence of K(+), Ca(2+), Na(+) and SO(4) (2-) ions have little influence on the potentiometric response of the sensor to chloride, but the pH has a significant influence on the potential value of the sensor at low chloride concentration. The potential reading of the sensor increases linearly with the solution temperature over the range from 5 to 45 °C. Meanwhile, an excellent polarization behavior is proven by galvanostatic and potentiodynamic tests. All of the results reveal that the developed sensor has a great potential for monitoring chloride ions in concrete environments. PMID:22163467

  3. Lactated Ringer's solution or 0.9% sodium chloride as fluid therapy in pigeons (Columba livia submitted to humerus osteosynthesis

    Adriano B. Carregaro

    2015-01-01

    Full Text Available The study aimed to compare the effects of intraosseous infusion of lactated Ringer's and 0.9% sodium chloride solutions on the electrolytes and acid-base balance in pigeons submitted to humerus osteosynthesis. Eighteen pigeons were undergoing to isoflurane anesthesia by an avalvular circuit system. They were randomly assigned into two groups (n=9 receiving lactated Ringer's solution (LR or 0.9% sodium chloride (SC, in a continuous infusion rate of 20mL/kg/h, by using an intraosseous catheter into the tibiotarsus during 60-minute anesthetic procedure. Heart rate (HR, and respiratory rate (RR were measured every 10 min. Venous blood samples were collected at 0, 30 and 60 minutes to analyze blood pH, PvCO2, HCO3 -, Na+ and K+. Blood gases and electrolytes showed respiratory acidosis in both groups during induction, under physical restraint. This acidosis was evidenced by a decrease of pH since 0 min, associated with a compensatory response, observed by increasing of HCO3 - concentration, at 30 and 60 min. It was not observed any changes on Na+ and K+ serum concentrations. According to the results, there is no reason for choosing one of the two solutions, and it could be concluded that both fluid therapy solutions do not promote any impact on acid-base balance and electrolyte concentrations in pigeons submitted to humerus osteosynthesis.

  4. Modeling of extraction equilibrium of Zn(II) from chloride solutions using TBP

    Zinc protective layers are commonly used to protect steel goods from corrosion. Solvent extraction and ion exchange can be used to remove zinc(II) from spent pickling solutions. The aim of presented work was to perform the detailed studies with tributyl phosphate taking into account different concentrations of zinc(II) and high concentrations both of proton and chloride ions. The obtained extraction isotherms of Zn(II) from chloride solutions were used to modeling extraction equilibrium, and equilibrium constant were calculated. The obtained results shown that zinc(II) could be effectively stripped from the organic phase with water

  5. Reaction of cobalt molybdophosphate with alcoholic solutions of tetraethoxysilane and oxozirconium(IV) chloride

    Interaction of cobalt molybdophosphate with alcohol solutions of tetraethoxysilane and oxozirconium chloride was studied using the methods of IR spectroscopy and thermal analysis with an aim of ascertaining the potentiality of the reagents application for production of thermochrome materials. It was ascertained that as a results of interaction between cobalt molybdophosphate and tetraethoxysilane solution the heteropolyanion [PMo12O40]3- was transformed into lacunar form [HxPMo11O39]7-x. The hydrolysis processes occurring in compositions with oxozirconium chloride does not permit stabilizing the structure of the heteropolycompound responsible for thermochrome transitions

  6. Acidizing carbonate reservoirs with chlorocarboxylic acid salt solutions

    Richardson, E.A.; Scheuerman, R.F.; Templeton, C.C.

    1978-10-31

    A carbonate reservoir is acidized slowly by injecting an aqueous solution of a chlorocarboxylic acid salt so that the rate of the acidization is limited to the rate at which an acid is formed by the hydrolyzing of the chlorocarboxylate ions. The rate at which a chlorocarboxylic acid salt hydrolyzes to form an acid provides the desired rate of acid-release. A more complete acid-base reaction by chloroacetic acid, as compared to formic, acetic, and proprionic, is due to its being a much stronger acid. The pKa of chloroacetic acid is 2.86, whereas that of formic acid is 3.75, and that of acetic acid is 4.75. The pKa of a solution of a weak acid is the pH exhibited when the concentration of undissociated acid equals the concentration of the acid anion. 14 claims.

  7. A Model Approach for Finding Cleaning Solutions for Plasticized Poly(Vinyl Chloride) Surfaces of Collections Objects

    Sanz Landaluze, Jon; Egsgaard, Helge; Morales Munoz, Clara;

    2014-01-01

    This study focused on developing a surface cleaning treatment for one type of commercially available plasticized poly(vinyl chloride). The effects of cleaning solutions on samples of plasticized poly(vinyl chloride) were examined by several methods. The sample surface, prior to and after artificial...... solutions for the plasticized poly(vinyl chloride) used in the study was found. In addition, a specific method to tailor cleaning mixtures for plasticized poly(vinyl chloride) objects was developed by means of Hildebrand solubility parameters and the formulation of a Plasticizer Index calculated by...... cleaning methods for plasticized poly(vinyl chloride) objects....

  8. Inclusion polymerization of vinyl chloride monomer in deoxycholic acid host via γ-ray irradiation

    Inclusion polymerization of vinyl chloride monomer (VCM) was studied in the system of 3α, 12α -dihydroxy-5β-cholan-24-oic acid (deoxycholic acid, DCA). DCA-VCM inclusion compound system was originally prepared by guest intercalation technique in DCA guest free crystal. The inclusion polymerization of DCA-VCM by γ-irradiation at total dose 2 Mrad, gives a syndiotactic rich polyvinyl chloride (PVC) as can be confirmed by FT-IR and FT-NMR. (author)

  9. Conductivity of Thionyl Chloride-Lithium Tetrachloroaluminate Solutions

    Berg, Rolf W.; Hjuler, H. A.; Søndergaard, A. P. L.;

    1989-01-01

    The specific conductivity of solutions of LiAlCl4 dissolved in SOCl2 was determined as a function of composition andtemperature. An analytical expression from which the conductivity can be calculated is given as a function of the molefraction of LiAlCl4 and temperature in the ranges from 0° to 0....

  10. Rheology and viscosity scaling of gelatin/1-allyl-3-methylimidazolium chloride solution

    Qiao, Congde; Li, Tianduo; Zhang, Ling; Yang, Xiaodeng; Xu, Jing

    2014-05-01

    Gelatin/1-allyl-3-methylimidazolium chloride solutions are prepared by using the ionic liquid 1-allyl-3-methylimidazolium chloride as solvent. The rheological properties of the gelatin solutions have been investigated by steady shear and oscillatory shear measurements. In the steady shear measurements, the gelatin solutions with high concentration show a shear-thinning flow behavior at high shear rates, while another shear thinning region can be found in the dilute gelatin solutions at low shear rates. The overlap concentration of gelatin in [amim]Cl is 1.0 wt% and the entanglement concentration is a factor of 4 larger (4.0 wt%). The high intrinsic viscosity (295 mL/g) indicates that the gelatin chains dispersed freely in the ionic liquid and no aggregation phenomenon occurs in dilute gelatin solution. The frequency dependences of modulus changed obviously with an increase in gelatin concentration. The empirical time-temperature superposition principle holds true at the experimental temperatures.

  11. Experimental study of concentrated solutions containing sodium and chloride pollutants in SG flow restricted areas

    You, D.; Lefefre, S.; Feron, D. [CEA-Saclay, Lab. d' Etude de la Corrosion Aqueuse, Gif-sur-Yvette (France); Vaillant, F. [EDF-Les Renardieres - DRD/EMA, Moret-sur-Loing (France)

    2002-07-01

    In steam generators, the hideout processes occur in flow restricted areas. Non volatile pollutants, i.e. species less soluble in the vapour phase than in the liquid water phase, accumulate such as sodium hydroxide or sodium chloride. The thermodynamic equilibrium between these two phases is described in terms of liquid-vapour equilibrium constants for soluble species and boiling constant for the solvent. The presented experimental investigation has been realised with the EVA device: the boiling pressure evolution has been measured during the hideout process of sodium hydroxide and sodium chloride aqueous solutions. The results clearly demonstrated that high sodium hydroxide aqueous solutions are thermodynamically possible while with sodium chloride, it seems that precipitation occurs before. (authors)

  12. Experimental study of concentrated solutions containing sodium and chloride pollutants in SG flow restricted areas

    In steam generators, the hideout processes occur in flow restricted areas. Non volatile pollutants, i.e. species less soluble in the vapour phase than in the liquid water phase, accumulate such as sodium hydroxide or sodium chloride. The thermodynamic equilibrium between these two phases is described in terms of liquid-vapour equilibrium constants for soluble species and boiling constant for the solvent. The presented experimental investigation has been realised with the EVA device: the boiling pressure evolution has been measured during the hideout process of sodium hydroxide and sodium chloride aqueous solutions. The results clearly demonstrated that high sodium hydroxide aqueous solutions are thermodynamically possible while with sodium chloride, it seems that precipitation occurs before. (authors)

  13. Chemical behaviour of plutonium in aqueous chloride solutions

    The chemical behaviour of Plutonium has been investigated in concentrated NaCl solutions in the neutral pH range. The α-radiation induced radiolysis reactions oxidize the Cl--ion to Cl2, HClO, ClO- and other species, which produce a strongly oxidizing medium. Under these conditions the Pu ions of lower oxidation states are readily oxidized to Pu(VI), which then undergo depending on the pH of the solution, various chemical reactions to produce PuO2Cln, PuO2(ClO)m or PuO2(OH)x species. In addition to primary radiolysis reactions taking place in NaCl solutions, the reactions leading to the PuO2(Cl)n and PuO2(ClO)m species have been characterized and quantified systematically by spectroscopic and thermodynamic evaluation. The redox and complexation reactions of Pu ions under varying NaCl concentration, specific α-activity and pH are discussed. (orig.)

  14. Crevice corrosion behaviour of titanium grades-2 and -12 in hot aqueous chloride solution - the effect of chloride concentration

    The crevice corrosion of Grades-2 (Ti-2) and -12 titanium (Ti-12) has been studied at a temperature of 150oC in solutions ranging in sodium chloride concentration from 0.27 mol·L-1 to 5.0 mol·L-1. A technique in which an artificially creviced electrode was coupled through a zero resistance ammeter to a large counter electrode was used to follow the potential of the crevice specimen and the coupled current due to oxygen reduction on the coupled electrode. The total amount of crevice corrosion which occurred on the specimen was estimated from weight change measurements. The depth of penetration due to crevice corrosion was measured using a combination of metallographic and image analysis techniques. Crevice corrosion of Ti-2 continued, without repassivation, until all the oxygen within the sealed pressure vessel system was exhausted. The weight change was proportional to the maximum depth of penetration and corrosion was observed to be quite generally distributed throughout the creviced area. Corrosion profiles (i.e., percentage of the creviced area corroded versus the depth of penetration) show a localized corrosion process preceding a more general corrosion front. The extent and rate of crevice propagation and the depth of maximum penetration, all decrease with increasing chloride concentration, but their dependence on this concentration is not major. By comparison, both the extent and rate of crevice corrosion of Ti-12 are dependent on chloride concentration increasing substantially for concentrations >0.5 mol·L-1 but decreasing again for concentrations >3.0 mol·L-1. However, at all chloride concentrations, the crevice repassivated before all the available oxygen was depleted; i.e., the extent of crevice corrosion is severely limited. Measurements of the depths of corrosion penetration show that, for Ti-12, penetration within the crevice occurs much more locally than for Ti-2. In fact, if a general corrosion front can be discerned at all, it is ∼10

  15. [Glucose-fatty acids cycle in cobalt chloride-induced oxidative stress in rats].

    Kaliman, P A; Okhrimenko, S M

    2005-01-01

    It was found that the glucose-fatty acids cycle functioned under the oxidative stress, caused by injection of cobalt chloride solution in albino rats. This cycle promoted the adaptation of metabolism and rehabilitated the homeostasis under extreme conditions. Its functioning was regulated by prolonged (during 2-24 hours) rise in activity of amino acids catabolism enzymes (e.g. tyrosine aminotransferase, arginase) and activation of glyconeogenesis after the mobilisation of liver glycogen. This contributed to increase in glucose and free fatty acids contents in blood. The latter is additionally provided by lipid mobilisation under stress. Tyrosine aminotransferase activation occurred both on the transcription level and by enabling of other mechanisms, which probably concerned the stabilisation of this enzyme. Preliminary injection of alpha-tocopherol in vivo significantly decreased the rise in tyrosine aminotransferase and arginase activities and the rate of erythrocyte hemolysis but did not disable them in full. This made evident that in regulation of the glucose-fatty acids cycle not only active metabolites of oxygen but also Co ions were directly enabled. PMID:16335249

  16. Acetic acid extraction from aqueous solutions using fatty acids

    IJmker, H.M.; Gramblicka, M.; Kersten, S.R.A.; Ham, van der A.G.J.; Schuur, B.

    2014-01-01

    A major challenge for production of acetic acid via bio-based routes is cost-effective concentration and purification of the acetic acid from the aqueous solutions, for which liquid–liquid extraction is a possible method. A main challenge in extraction of acetic acid from dilute aqueous solutions is

  17. Viscosity of aqueous-glyceric solutions of potassium, rubidium and cesium chlorides

    Results of viscometric investigation of the solutions of rubidium and cesium chlorides (also potassium chloride for comparison) in mixtures water-glycerine at 15, 25, 35 and 45 deg C are presented. Glycerine content constituted 0.01; 0.03; 0.05; 0.07; 0.11 molar fractions. It is shown that the range of viscosity values lower as compared to the ones for pure solvent are the wider the lower the temperature and glycerine content are (in the range of 0.01-0.11 molar fractions). The composition-viscosity, temperature-viscosity diagrams are presented

  18. Separation of hafnium from zirconium in their tetrachloride solution in molten alkali metal chlorides

    Salyulev, A.B.; Kudyakov, V.Ya.; Smirnov, M.V.; Moskalenko, N.I. (AN SSSR, Sverdlovsk. Inst. Ehlektrokhimii)

    1984-08-01

    The coefficient of HfCl/sub 4/ and ZrCl/sub 4/ separation in the process of vapour sublimation from their solutions in molten NaCl, KCl, CsCl, NaCl-KCl and NaCl-CsCl equimolar mixtures is found to vary in the series from approximately 1.10 to approximately 1.22 and practically not to depend on the temperature (in the 600-910 deg) range and concentration (2-25 mol.% ZrCl/sub 4/+HfCl/sub 4/). HfCl/sub 4/ and ZrCl/sub 4/ are shown to form almost perfect solutions with each other, which in their turn form imperfect solutions with molten alkali metal chlorides, with the strength of hafnium complex chloride anions increasing higher than that of zirconium in the series from NaCl to CsCl.

  19. Separation of hafnium from zirconium in their tetrachloride solution in molten alkali metal chlorides

    The coefficient of HfCl4 and ZrCl4 separation in the process of vapour sublimation from their solutions in molten NaCl, KCl, CsCl, NaCl-KCl and NaCl-CsCl equimolar mixtures is found to vary in the series from approximately 1.10 to approximately 1.22 and practically not to depend on the temperature (in the 600-910 deg) range and concentration (2-25 mol.% ZrCl4+HfCl4). HfCl4 and ZrCl4 are shown to form almost perfect solutions with each other, which in their turn form imperfect solutions with molten alkali metal chlorides, with the strength of hafnium complex chloride anions increasing higher than that of zirconium in the series from NaCl to CsCl

  20. Behaviour of rare platinum metals during precipitation from chloride solutions by sulfur liquor

    Sulfide precipitation of ruthenium, rhodium and iridium for their supplementary extraction from chloride solutions is studied. The behaviour of rare platinum metals (RPM) under the action on their chloride solutions of sulfer liquor mainly consisting of NaSsub(x) polysulfides, is related to the formation of sulfides and soluble thiosalts. The ratio of the forms depends on pH value. In the series Ir-Rh-Ru the tendency for sulfide formation increases, and thiosalt stability decreases. The treatment of the solutions by sulfur liquor with subsequent correction of pH value permits to extract RPM into precipitate quite completely, at that, RPM residual concentration in mother liquor does not exceed 0.5-0.7 mg/l. It is pointed out, that under the conditions studied only ruthenium is precipitated quantitatively, for which the following parameters can be considered optimal: 80-100 deg C, pH=1-2, the process duration 60-90 min

  1. Corrosion behaviour of WC-Co based hardmetal in neutral chloride and acid sulphate media

    Bozzini, B.; Serra, M.; Fanigliulo, A.; Bogani, F. [Lecce Univ. (Italy). Dipt. di Ingegneria dell' Innovazione; Gaudenzi, G.P. de [Harditalia s.r.l. (OMCD Group), Genova (Italy)

    2002-05-01

    A comparative study of the corrosion behaviour of WC-Co based hardmetals with Ni and Cr{sub 3}C{sub 2} additions is carried out. The aggressive environments are neutral and acidic aerated aqueous solutions of NaCl and H{sub 2}SO{sub 4}. This study is based on electrochemical (linear sweep voltammery), compositional (surface EDX analyses, AAS analyses of attack solutions), structural (XRD) and morphological (SEM) investigations. Electrochemical figures of merit were computed from linear sweep voltammograms in order to rank the corrosion behaviour close to free-immersion conditions in the studied environments and with presence of oxidising agents. EDX and XRD analyses allow to accurately characterise the penetration depth of the attack as well as the preferential dissolution of the constituents. Binders containing Ni show a significantly improved corrosion resistance in the studied systems. The amount of Ni in the binder is the single most important factor affecting corrosion performance. Cr{sub 3}C{sub 2} additions to hardmetals with lower-Ni binders cannot balance the effect of Ni, but give an improved resistance in neutral chloride-containing solutions. (orig.)

  2. Kinetics of the oxidative hydroxylation of sodium hypophosphite in the presence of copper (II chloride modified by humic (fulvo- acid

    Zhaksyntay Kairbekov

    2012-12-01

    Full Text Available It was established that in soft conditions (50-70oC, PO2 = 1 atm sodium hypophosphite effectively is oxidized by oxygen in water solutions of copper(II chloride  to give mainly a phosphorous acid. Humic (fulvo- acid was extracted from brown coal of domestic deposit Kiyakty. For determination of optimum parameters of fulvo-acid extraction the laboratory experiments were carried out using the method of experiment planning. The kinetics, the intermediate and final products, optimal conditions of new catalytic reaction of NaH2PO2 oxidation by oxygen in water solution were defined by kinetics, volumometry, redox-potentiometry and a titration.

  3. Crevice Corrosion Susceptibility of Alloy 22 in Fluoride and Chloride Containing Solutions

    Day, S D; Rebak, R B

    2004-11-22

    Alloy 22 (N06022) is highly resistant to crevice corrosion in pure chloride (Cl{sup -}) solutions. Little research has been conducted to explore the resistance of this alloy to other halides such as fluoride (F{sup -}) and bromide (Br{sup -}). Even less information is available exploring the behavior of localized corrosion for Alloy 22 in mixtures of the halide ions. Standard electrochemical tests such as polarization resistance and cyclic potentiodynamic polarization (CPP), were conducted to explore the resistance to corrosion of Alloy 22 in deaerated aqueous solutions of 1 M NaCl, 1 M NaF and 0.5 M NaCl + 0.5 M NaF solutions at 60 C and 90 C. Results show that the general corrosion rate was the lowest in the mixed halide solution and the highest in the pure chloride solution. Alloy 22 was not susceptible to localized corrosion in the pure fluoride solution. In 1 M NaCl solution, Alloy 22 was susceptible to crevice corrosion at 90 C. In the mixed halide solution Alloy 22 was susceptible to crevice corrosion both at 60 C and 90 C.

  4. Anodic behavior of hafnium in water-alcohol solutions of sodium chloride

    The mechanism of hafnium anodic solution in the systems: sodium chloride-isopropanol-glycerin-water is clarified. The corrosiveness of the studied electrolytes relative to hafnium is evaluated. It is shown that the solution mechanism changes with increase in the potential: after reaching the 0.4-0.5 V potential the process diffusion control changes for kinetic one. The hafnium anodic solution also changes with increase of temperature in the electrolyte wherein the treatment is conducted. In this case the change in the composition and properties of the change in the composition and properties of the oxide film on the metal constitute surface the basis of the mechanism change

  5. The precipitation of radioactive radium-226 from acidic chloride leach liquors with barium chloride

    The conventional barium chloride (BaClsub(2)) precipitation has been effective in the 99+ percent removal of radium-226 as radium-barium sulphate [RaBa(SOsub(4))sub(2)] sludge, from HCl liquors produced by laboratory and pilot leaches of Canadian uranium ores. Radium-226, due to its low-level radiation characteristics, is removed as it has been identified as an environmental and long-term health problem. The formation of the RaBa(SOsub(4))sub(2) sludge was aided due to adequate sulphate (SOsub(4)) concentrations in the HCl pilot liquors produced. Recyclable Rasup(226) concentrations of about 66 pCi/L, in treated effluents, will cost about 1/10 that of effluents below federal environmental guidelines of 10 pCi Rasup(226)/L. Toxic barium (Ba) will potentially build up in effluents as recyclable Rasup(226) concentrations around 66 pCi/L. Barium, in addition to being added to liquors as BaClsub(2) precipitant, is present in the radioactive ore and HCl leach liquors

  6. Liquid-Liquid Extraction and Separation of Co (II) and Ni(II) from Chloride Medium by bis (2,4,4-trimethylpentyl) dithio phosphinic acid in Kerosene

    The extraction of Co(II) and Ni(II) from chloride solutions using bis (2,4,4-trimethylpentyl) dithio phosphinic acid (CYANEX 301) in kerosene has been investigated. The various factors affecting the extraction process of Co(II) and Ni(II) by the investigated extractant such as contact time, ph, extractant and metal ion concentration as well as temperature, are separately investigated. The stripping of the extracted metal ions from loaded organic solutions is also carried out using different stripping reagents. The results were used to assess the conditions for maximum Co(II)/Ni(II) separation from chloride medium using CYANEX 301

  7. Chemical modification of Sago starch by solvent less esterification with fatty acid chlorides

    Sago starch was chemically modified by esterification reaction with fatty acid chlorides to produce a non-polar sago ester in the absence of an organic solvent. The sago esters were prepared by first pretreatment of sago starch with excess formic acid at 90 degree Celsius for 40 minutes followed by acetylation with acid chloride (octanoyl and lauroyl chlorides). The maximum yields of 80 % and 73 % with the same degree of substitution (DS) of 1.2 for octanoate and lauroate sago esters were obtained respectively. The presence of ester carbonyl group in the FT-IR spectra of the ester products showed that the sago starch has been esterified. The intensities of carbonyl and methyl peaks were decreased with the increasing of DS. (author)

  8. Kinetics of the oxidative hydroxylation of tetraphosphorus in the presence of copper(II chloride modified by humic (fulvo- acid

    Zhaksyntay Kairbekov

    2012-12-01

    Full Text Available It was established that in mild conditions (50-70 oC, РО2= 1 atm white phosphorus effectively is oxidized by oxygen in water-toluene solutions of copper(II chloride modified by humic (fulvo- acid to give mainly phosphoric acid. Humic (fulvo- acid was extracted from brown coal of domestic deposit Kiyakty. For determination of optimum parameters of fulvo-acid extraction the laboratory experiments were carried out using the method of experiment planning. The kinetics, intermediate and final products, optimum conditions of new catalytic reaction of P4 oxidation by oxygen in water medium were defined by kinetics, volumometry, redox-potentiometry, 31Р{1Н} NMR spectroscopy and  titration. 

  9. Phase equilibrium of methane hydrate in silica sand containing chloride salt solution

    Highlights: • Methane hydrate equilibria in silica sand-ionic solution are obtained. • Hydrate equilibria in fine sand-solution shift more than single sand or solution. • Electrostatic and capillary forces affect hydrate equilibria in fine sand-solution. • Hydrate equilibria in coarse sand-solution agree with those in single solution. • Hydrate equilibria in coarse sand-solution are mainly affected by ions. - Abstract: Hydrate equilibrium is the most important foundation for other hydrate issues, especially for marine environment condition. In this work, the silica sand containing NaCl/MgCl2/CaCl2 aqueous solution were used to simulate marine sediment for investigating methane hydrate equilibrium using isochoric multi-step heating dissociation method. All measurements were performed in a temperature and pressure range of (279.5 to 289.7) K and (8.32 to 17.52) MPa, respectively. The results suggest that the equilibrium of methane hydrate in fine-grained silica sand containing chloride salt solution shifts more greatly to the left relative to that in single silica sand or solution. This is because water molecules reduce more chances to combine with gas molecules that is caused by the capillary force and the electrostatic attractions from the surface and electrolyte ions. However, hydrate equilibrium in coarse-grained silica sand containing chloride salt solution is in rough agreement with that in ionic solution of the corresponding concentration that indicates that hydrate equilibrium is mainly influenced by ions while the impact of solid particles is negligible

  10. Performance of cellulose acetate butyrate membranes in hyperfiltration of sodium chloride and urea feed solution

    Wydeven, T.; Leban, M.

    1973-01-01

    Cellulose acetate butyrate (CAB) membranes are shown to give high salt and urea rejection with water flux of about 3 gallons/sq ft per day at 600 psig. Membranes prepared from a formulation containing glyoxal show a significant increase in flux and decrease in salt and urea rejection with drying time. Zero drying time gives maximum urea and salt rejection and is therefore most suitable for hyperfiltration of sodium chloride and urea feed solution.

  11. Corrosion-fatigue lifetime of Aluminium–Copper–Lithium alloy 2050 in chloride solution

    Guérin, Mathilde; Alexis, Joël; Andrieu, Eric; Blanc, Christine; Odemer, Grégory

    2015-01-01

    International audience The fatigue behaviour of Aluminium–Copper–Lithium 2050 alloy under two metallurgical states (T34 and T84) was studied in air for healthy and pre-corroded samples in a 0.7 NaCl solution. The results were compared to those obtained during fatigue–corrosion tests performed in a similar chloride medium. Preliminary corrosion tests demonstrated that the T34 metallurgical state was susceptible to intergranular corrosion, while the T84 metallurgical state was susceptible to...

  12. Passivation of duplex stainless steel in solutions simulating chloride-contaminated concrete

    Takenouti, H.; Soriano, L; Palacín, S.; Gutiérrez, A.; Velasco, F.; Blanco, G; Bautista, A.

    2007-01-01

    Most studies published to date on the corrosion behaviour of stainless reinforcing steel are based on austenitic steel. The market presence of corrugated duplex steel is growing, however. The present study compared passivity in 2205 type duplex and 304 type austenitic stainless steel. Polarization tests in chloride-containing Ca(OH)2 solutions confirmed the exceptional performance of duplex steels. X-ray photoelectronic spectroscopy (XPS) showed that the passive layer generated on duplex stai...

  13. Hydration of the chloride ion in concentrated aqueous solutions using neutron scattering and molecular dynamics

    Pluhařová, Eva; Fischer, H. E.; Mason, Philip E.; Jungwirth, Pavel

    2014-01-01

    Roč. 112, 9/10 (2014), s. 1230-1240. ISSN 0026-8976 R&D Projects: GA ČR GBP208/12/G016; GA MŠk LH12001 Grant ostatní: GA MŠk(CZ) LM2010005 Institutional support: RVO:61388963 Keywords : lithium * solution * molecular dynamics * chloride * neutron scattering Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.720, year: 2014

  14. Pressure-induced unfolding of lysozyme in aqueous guanidinium chloride solution

    Sasahara, K; Nitta, K

    1999-01-01

    The pressure-induced unfolding of lysozyme was investigated in an aqueous guanidinium chloride solution by means of ultraviolet spectroscopy. Assuming a two-state transition model, volume changes were calculated from the slope of free energy vs. pressure plots over a temperature range of 10 to 60 degrees C. Between 25 and 60 degrees C, almost constant volume changes were observed in the transition region, which was reflected in almost identical slopes of the free energy change vs. pressure pl...

  15. Pressure-induced unfolding of lysozyme in aqueous guanidinium chloride solution.

    Sasahara, K; Nitta, K

    1999-01-01

    The pressure-induced unfolding of lysozyme was investigated in an aqueous guanidinium chloride solution by means of ultraviolet spectroscopy. Assuming a two-state transition model, volume changes were calculated from the slope of free energy vs. pressure plots over a temperature range of 10 to 60 degrees C. Between 25 and 60 degrees C, almost constant volume changes were observed in the transition region, which was reflected in almost identical slopes of the free energy change vs. pressure pl...

  16. Threshold Chloride Concentration of Stainless Steels in Simulated Concrete Pore Solution

    Wang, Hailong; Ling, Jiayan; Sun, Xiaoyan

    2016-01-01

    To evaluate whether stainless steel can replace carbon steel as rebar in reinforced concrete structures exposed to aggressive environment, the threshold chloride concentration of carbon steel, austenitic and duplex stainless steels were experimentally studied in this paper. The solutions with pH ranging from 9.5 to 13.6 were used herein to simulate the pore liquids in both alkaline and carbonated concretes. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests we...

  17. Effect of chloride ions on the corrosion and electrochemical behavior of titanium in neutral solutions

    Mandzhgaladze, S.N. (Inst. of Metallurgy, Tbilisi, USSR); Mikaberidze, M.P.; Pirtskhalava, D.N.; Vasil' ev, Yu.B.; Bagotskii, V.S.

    1976-01-01

    A solution of NaCl was buffered with a phosphate buffer, and the potential was measured relative to a saturated silver chloride electrode. Polarization curves for cathodically reduced and oxidized titanium are shown, as well as the effect of NaCl concentration on the corrosion current, the steady-state corrosion potential, the cathodic currents, and the anodic currents for cathodically reduced and anodically oxidized titanium. The corrosion potential for oxidized titanium is strongly shifted in the positive direction, and the corrosion current and the dissolution current in the passive state are almost 10 times higher than for prereduced titanium. The different effects of the chloride ions on the rates of the cathode and anode processes result in a practically constant corrosion current for cathodically reduced titanium when c/sub Cl/sup -// less than 5 N. In the case of the oxidized titanium surface, the simultaneous increase in the rate of both the cathode and the anode process with increasing chloride ion concentration results in the increase of the corrosion current proportional to a fractional power of the bulk chloride ion concentration. 2 figures. (RWR)

  18. Chloride transport and its sensitivities to different boundary conditions in reclaimed soil solutions filled with fly ash

    Xiao-Yang CHEN; Jia-Ping YAN; Shi-Wen ZHANG

    2013-01-01

    Chloride ion transport in reclaimed soil solutions filled with fly ash (FA) was investigated by measuring the hydraulic parameters (i.e.water retention curves and hydraulic conductivity) of three substrates,namely GSL,GFA,and CFA.Similar simulations were carried out under certain weather conditions.The different boundary conditions of chloride transport were also discussed from FA texture,cover soil thickness,groundwater table level,and initial chloride concentration.Furthcrmore,the sensitivities of chloride ions to these effect factors were analyzed.The results show that the different top soil thickness and initial chloride concentration have no effect on salinity of topsoil solution in the monitoring points,but they can clearly change the chloride concentration of FA layers.The sensibilities from top soil thickness and initial chloride content are exceedingly weak to the salinity balance based on two dimensions of the time and concentration.While the different FA texture and groundwater table not only affect the salinity equilibrium process of the whole reclaimed soil profile,but also change its balance state.Generally,coarse FA particles and high groundwater table can defer the salinity balance process of the reclaimed soil solution,and they also increase the chloride concentration of FA layer solutions,and even topsoil ones.

  19. Pitting of steam-generator tubing alloys in solutions containing thiosulfate and sulfate or chloride.

    Zhang, William; Carcea, Anatolie G; Newman, Roger C

    2015-01-01

    The pitting of nuclear steam generator tubing alloys 600, 690 and 800 was studied at 60 °C using dilute thiosulfate solutions containing excess sulfate or (for Alloy 600) chloride. A potentiostatic scratch method was used. In sulfate solutions, all alloys pitted at low potentials, reflecting their lack of protective Mo. The alloys demonstrated the most severe pitting at a sulfate : thiosulfate concentration ratio of ∼40. Alloy 600 pitted worst at a chloride : thiosulfate ratio of ∼2000. The results are interpreted through the mutual electromigration of differently charged anions into a pit nucleus, and differences in the major alloy component. PMID:25898311

  20. Corrosion Behavior of Compocasted ZA27/SiCp Composites in Sodium Chloride Solution

    Bobić, B.; I. Bobić; A. Vencl; M. Babić; S. Mitrović

    2016-01-01

    The corrosion behavior of particulate ZA27/SiCp composites in an aerated sodium chloride solution was studied. The composites were synthesized via compocasting with addition of 1, 3 and 5 wt.% SiC particles in the matrix alloy. Composite samples were immersed for 30 days in the 3.5 wt.% NaCl solution open to the atmospheric air. Surface appearance and microstructure of the composites were examined by means of optical microscopy and scanning electron microscopy, while corrosion rates of the co...

  1. Processes for working-up an aqueous fluosilicic acid solution

    Alpha O. Toure

    2012-11-01

    Full Text Available Aqueous fluosilicic acid solutions were once considered to be only adverse by-products of phosphoric acid production, which required treatment to prevent ecosystem destruction when discharged into the sea. However, a range of chemicals can be generated by the transformation of this industrial waste product. Through experiments undertaken in the laboratory, we have shown the possibility of caustic soda production. Volumetric analysis showed caustic soda to be present as a 6%– 7%solution with yields of about 70% – 80%by weight. Two processes were investigated for the caustification of sodium fluoride, using different precipitates: sodium chloride and ethanol and are described by modelling caustification curves. The activation energies of precipitation determined by semi-empirical correlations showed that precipitation by ethanol (EA = 933.536 J/mol was more successful than precipitation by sodium chloride (EA = 7452.405 J/mol. Analyses performed on the precipitates highlighted compositions that are essential and useful constituents in the cement industry.

  2. CATALYTIC ESTERIFICATION OF CARBOXYLIC ACIDS WITH ALCOHOLS BY SULFO—POLYVINYL CHLORIDE

    YuShanxin; ZHAOZongbao; 等

    1993-01-01

    Polyvinyl Chloride reacted with chlorosulfonic acid to from a polymer catalyst PVC-SO3H.This polymer catalyst was found to have high activity for resterification reaction between carboxylic acids and alcohols.This paper deals with the conditions in synthesis of n-butlyacetate catalyzed with PVC-SO3H.The PVC-SO3H was used as a catalyst for preparing 11 esters of acetic acid,propionic acid and butyric acid with the yields of 82-92%.

  3. Bipolar membrane electrodialysis for generation of hydrochloric acid and ammonia from simulated ammonium chloride wastewater.

    Li, Ya; Shi, Shaoyuan; Cao, Hongbin; Wu, Xinmin; Zhao, Zhijuan; Wang, Liying

    2016-02-01

    Simulated ammonium chloride wastewater was treated by a lab-scale bipolar membrane electrodialysis for the generation of HCl and NH3·H2O and desalination. The influence of initial concentration of NH4Cl, current density, salt solution volume, initial concentration of acid and base and membrane stack structure on the yields of HCl and NH3·H2O was investigated. The current efficiency and energy consumption were also examined under different conditions. The results showed that, at the current density of 48 mA/cm(2), the highest concentration of HCl and NH3·H2O with initial concentration of 110 g/L NH4Cl was 57.67 g/L and 45.85 g/L, respectively. Higher initial concentration of NH4Cl was favor to reduce unit energy consumption and increase current efficiency of the BMED system. The membrane stack voltage of BMED increased quickly under constant current when the concentration of NH4Cl contained in the solution of salt compartment was depleted below the "inflection point concentration" about 8000 mg/L. It means that the concentration of NH4Cl below 8000 mg/L was no longer suitable for BMED because of higher energy consumption. The HCl and NH3·H2O concentration increased more quickly following the increase of current density. When increasing the volume of NH4Cl, the concentration of HCl and NH3·H2O also increased. The high initial concentration of acid and base could improve the final concentration of them, while the growth rate was decreased. Compared with the BMED system with three compartments, the growth rate of HCl concentration with the two compartments was higher and its unit energy consumption was lower. It meant that the performance of the BMED system could be improved by optimizing operation conditions. The application feasibility of the generation of HCl and NH3·H2O and desalination of ammonium chloride wastewater by BMED was proved. PMID:26674548

  4. Standard test method for evaluating stress-corrosion cracking of stainless alloys with different nickel content in boiling acidified sodium chloride solution

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This test method describes a procedure for conducting stress-corrosion cracking tests in an acidified boiling sodium chloride solution. This test method is performed in 25% (by mass ) sodium chloride acidified to pH 1.5 with phosphoric acid. This test method is concerned primarily with the test solution and glassware, although a specific style of U-bend test specimen is suggested. 1.2 This test method is designed to provide better correlation with chemical process industry experience for stainless steels than the more severe boiling magnesium chloride test of Practice G36. Some stainless steels which have provided satisfactory service in many environments readily crack in Practice G36, but have not cracked during interlaboratory testing using this sodium chloride test method. 1.3 This boiling sodium chloride test method was used in an interlaboratory test program to evaluate wrought stainless steels, including duplex (ferrite-austenite) stainless and an alloy with up to about 33% nickel. It may also b...

  5. Effects of solution pH and synthetic method on destabilization process of polytitanium-silicate-chloride.

    Huang, Xin; Gao, Baoyu; Sun, Yangyang; Yue, Qinyan; Wang, Yan; Li, Qian

    2016-07-01

    Effect of solution pH on coagulation performance and flock properties of a novel inorganic polymer coagulant-polytitanium-silicate-chloride (PTSC) in humic acid-kaolin water treatment was investigated in this work. PTSC was synthesized by two approaches: composite and co-complexion, denoted as PTSCm and PTSCc respectively. The effect of the synthetic method was also considered. Results indicated that turbidity and DOM removal were improved by addition of polysilicic acid, especially under acidic condition. PTSCc achieved slightly better DOM removal than that of PTSCm. Flocks formed under acidic condition was smaller than those form under alkaline condition. In addition, flocks formed by PTSCc were larger than PTSCm flocks. Results also indicated that flock strength and recovery ability was slightly improved by the addition of PSiA. Moreover, under acidic condition, PTSC flocks had larger fractal dimension with more compact structure, especially for PTSCm flocks. In contrast, they were looser compared with PTC flock, especially for PTSCm flocks under neutral and alkaline conditions. PMID:26994354

  6. Reasons for different solubility of alkali metal chlorides in cadmium nitrate solutions

    Maximum solubility of MCl salts (M=Li, Na, K, Cs) in solutions of cadmium nitrate and perchlorate of different concentration was measured in detail for studying the reason for different solubility of alkali metal chlorides in aqueous solutions of cadmium nitrate with concentration of 0.9 and 4.1 mol/l. It is shown that in the framework of phenomenological model of the solutions concentrated solutions of salts forming several crystallohydrates can be considered as a system of mixed solvents. In this case, preferable interaction of LiCl and CsCl with the Cd(NO3)2·9H2O type solvent, while NaCl and KCl - with the Cd(NO3)2·4H2O type solvent can be mentioned

  7. Sulphate analysis in uranium leach iron(III) chloride solutions by inductively coupled argon plasma spectrometry

    Inductively coupled Argon Plasma Spectrometry is used for the indirect determination of sulphate in iron(III) chloride leach solution of Elliot Lake uranium ores via addition of a known amount of barium ions and analyzing for excess of barium. The ore contains ∼ 7 wt% pyrite, FeS2, as the major mineral which oxidizes to generate sulphate during leaching with Fe(III). The effects of pH, the concentrations of Fe(III) and chloride ions and for presence of ethanol in the test samples on the accuracy of analysis are studied. It is found that unlike the Rhodizonate method, removal of iron(III) from or addition of ethanol to the test sample prior to analysis are not required. Linear calibration curves are obtained. (author)

  8. NIR Spectroscopic Properties of Aqueous Acids Solutions

    Mohd Zubir MatJafri

    2012-06-01

    Full Text Available Acid content is one of the important quality attributes in determining the maturity index of agricultural product, particularly fruits. Despite the fact that much research on the measurement of acidity in fruits through non-destructive spectroscopy analysis at NIR wavelengths between 700 to 1,000 nm has been conducted, the same response towards individual acids is not well known. This paper presents NIR spectroscopy analysis on aqueous citric, tartaric, malic and oxalic solutions through quantitative analysis by selecting a set of wavelengths that can best be used to measure the pH of the solutions. The aquaphotomics study of the acid solutions has generated R2 above 0.9 for the measurement of all acids. The most important wavelengths for pH are located at 918–925 nm and 990–996 nm, while at 975 nm for water.

  9. Acid chloride leaching of Midwest Lake uranium ore (northern Saskatchewan, Canada)

    The feasibility of acid chloride leaching (i.e. alternative leaching process) of high-grade complex uranium ore was studied on Midwest Lake uranium ore, one of the main objectives of the work being to produce effluents and tailings almost free from radioisotopes and other toxic materials. Irrespective of leachants, uranium extractions were always high (∼99%). 32 refs.; 5 tabs

  10. Statics of uranium adsorption from chloride-fluoride solutions by aminocarboxylic polyampholytes

    Pakholkov, V.S.; Denisova, L.A.; Rychkov, V.N.

    1988-03-01

    The adsorption of uranium from UO/sub 2/Cl/sub 2/ solutions containing HCl, NH/sub 4/Cl, and HF using polyampholytes ANCB-1, ANCB-7, and ANCB-10, which were synthesized from the corresponding anion-exchange resins AN-31, AV-16D, and AN-61, has been investigated under static conditions. For pure chloride solutions, in a moderate HCl (or NH/sub 4/Cl) concentration range, adsorption occurs via a cation exchange mechanism. Anionic exchange is the main adsorption process for chloride-fluoride solutions containing HCl concentrations up to 2 M. These conclusions have been verified by IR spectroscopic data. The experimental results obtained for mixed chloride-fluoride solutions can be approximated using the following regression equations: (A/sub (0-3)/ = -0.83 + 0.13C/sub HF/ + 0.18C/sub HCl/ + 40.7C/sub U/ + 0.22C/sub HF/ x C/sub HCl/ - 10C/sub HCl/ x C/sub U/ + 30C/sub HF/ x C/sub U/ - 20C/sub HF/ x C/sub HCl/ x C/sub U/ (for the concentration range of HCl from 0 to 3.0 M); and A/sub (3-6)/ = -0.81 + 0.135C/sub HCl/ + 22C/sub U/ (for the HCl concentration range from 3.0 to 6.0 M). The variable A in these equations stands for the adsorptivity in mmole U/g.

  11. Influence of sodium chloride, pH, and lactic acid bacteria on anaerobic lactic acid utilization during fermented cucumber spoilage

    Cucumbers are preserved commercially by natural fermentations in 5% to 8% sodium chloride (NaCl) brines. Occasionally, fermented cucumbers spoil after the primary fermentation is complete. This spoilage has been characterized by decreases in lactic acid and a rise in brine pH caused by microbial ins...

  12. Degradation of ascorbic acid in ethanolic solutions.

    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

  13. Antifungal activity of essential oils when associated with sodium chloride or fatty acids

    Tantatoui-Elaraki, Abdelthafour; Errifi, Aziza

    1994-01-01

    The inhibition of mycelium growth in a Zygorhynchus sp. and an Aspergillus niger isolates was studied. The inhibition rates (IR) caused by 4 essential oils (EO), 5 fatty acids and sodium chloride at various concentrations were determined in Sabouraud Dextrose Agar.
    A synergy of action was observed between sodium chloride at 7.5% and the EO of thyme (0.04%), camomile (0.4%) and mugwort (0.2 and 0.1%) on A. niger and between ...

  14. Comparison of Inactivation and Unfolding of Calf Intestinal Alkaline Phosphatase in Guanidinium Chloride Solution

    张英侠; 闫淑莲; 刘永利; 席宏伟; 周海梦

    2002-01-01

    The changes in activity and unfolding of calf intestinal alkaline phosphatase (CIP) during denaturation in guanidinium chloride solutions of different concentrations were investigated using ultraviolet difference absorption spectra and fluorescence emission spectra. Unfolding and inactivation rate constants were measured and compared. The inactivation course is much faster than that of unfolding, which suggests that the active site of CIP containing two zinc ions and one magnesium ion is situated in a limited and flexible region of the enzyme molecule, which is more fragile to the denaturant than the protein as a whole.

  15. Pitting corrosion of friction stir welded aluminum alloy thick plate in alkaline chloride solution

    Xu Weifeng, E-mail: xwf1982@mail.nwpu.edu.c [School of Materials and Engineering, Northwestern Polytechnical University, Xi' an 710072 (China); Liu Jinhe; Zhu Hongqiang [School of Materials and Engineering, Northwestern Polytechnical University, Xi' an 710072 (China)

    2010-03-01

    The pitting corrosion of different positions (Top, Middle and Bottom) of weld nugget zone (WNZ) along thickness plate in friction stir welded 2219-O aluminum alloy in alkaline chloride solution was investigated by using open circuit potential, cyclic polarization, scanning electron microscopy and atomic force microscope. The results indicate that the material presents significant passivation, the top has highest corrosion potential, pitting potential and re-passivation potential compared with the bottom and base material. With the increase of traverse speed from 60 to 100 mm/min or rotary speed from 500 to 600 rpm, the corrosion resistance decreases.

  16. Corrosion cracking of Fe-Cr-Ni stainless steels in chloride solutions

    Tendency to chromium-nickel stainless steels to corrosion cracking in hot solutions of chlorides is connected with the presence or possibility of formation (in the process of deformation) of alpha-gamma phase boundary. Passive oxide film over the (α-γ) phase boundary is mostly defective. However, effect of defectness in the passive film on development of corrosion-mechanical rupture of the metal crystal lattice (crack growth) can manifest itself only at simultaneous presence of expanding stresses on the metal (driving thes zone apart), because of the narrow character of the this zone

  17. Fluxional behavior of a cadmium zwitterion complex: proton transport and tautomerism in methylene chloride solution.

    Anderson, Oren P; la Cour, Agnete; Berg, Andrew; Garrett, Andrew D; Wicholas, Mark

    2003-07-28

    The synthesis and structure of the tautomeric Cd(II) isoindoline zwitterion coordination compound [Cd(4'-MeLH)(NO(3))(2)].CH(3)OH (4'-MeLH = 1,3-bis[2-(4-methylpyridyl)imino]isoindoline) are reported. In methylene chloride solution, tautomer interconversion occurs as the N-H proton moves between the identical imine nitrogen atoms. We report the kinetics of proton transfer as followed by variable temperature (1)H NMR spectroscopy and demonstrate that methanol of solvation and adventitious water facilitate rapid proton transfer. PMID:12870937

  18. Pitting corrosion of friction stir welded aluminum alloy thick plate in alkaline chloride solution

    The pitting corrosion of different positions (Top, Middle and Bottom) of weld nugget zone (WNZ) along thickness plate in friction stir welded 2219-O aluminum alloy in alkaline chloride solution was investigated by using open circuit potential, cyclic polarization, scanning electron microscopy and atomic force microscope. The results indicate that the material presents significant passivation, the top has highest corrosion potential, pitting potential and re-passivation potential compared with the bottom and base material. With the increase of traverse speed from 60 to 100 mm/min or rotary speed from 500 to 600 rpm, the corrosion resistance decreases.

  19. Calcium ion activity in physiological salt solutions: influence of anions substituted for chloride

    Christoffersen, Gert Rene Juul; Skibsted, Leif H

    1975-01-01

    1. Substitution by different anions for chloride in physiological salt solutions leads to binding between Ca2+ and the anion. Experiments designed to test effects of Cl- therefore often show mixed effects of changes in Cl- and Ca2+ activity.   2. This mixed effect is demonstrated in neurons...... of the snail, Helix pomatia: current-voltage characteristics and membrane potential are described during reduction of extracellular Cl- using different anions as substitutes. Methylsulphate is concluded to be the best substitute in this preparation. 3. The association constants for the binding of Ca2...

  20. Investigation of the oxidation of hydrochloric acid in scrubbing solutions containing hydrogen peroxide

    Oxidation and absorption of nitrogen oxides by a solution containing sulphuric, nitric acids and hydrogen peroxide have been investigated. The oxidation of nitric oxide is dependent among others on hydrogen peroxide concentration total acidity and temperature. The absorption of N O2 by the scrubbing solution (H2 S O4,H N O3 and H2 O2) in all cases studied is not less than 98%. The oxidation of chloride into chlorine gas increases as the concentration of each of hydrochloric acid, nitric oxide and nitric acid increases. On the other hand as the concentration of hydrogen peroxide increases the amount of chlorine gas decreases. The results show that the oxidation of chloride into chlorine gas is mainly due to nitrogen dioxide. 7 fig., 2 tab

  1. Sulfate, chloride and fluoride retention in Andosols exposed to volcanic acid emissions

    Delmelle, Pierre; Delfosse, Thomas; Delvaux, Bruno

    2003-12-01

    The continuous emissions of SO{sub 2}, HCl and HF by Masaya volcano, Nicaragua, represent a substantial source of atmospheric S-, Cl- and F-containing acid inputs for local ecosystems. We report on the effects of such acid depositions on the sulfate, chloride and fluoride contents in soils (0-40 cm) from two distinct transects located downwind from the volcano. The first transect corresponds to relatively undifferentiated Vitric Andosols, and the second transect to more weathered Eutric Andosols. These soils are exposed to various rates of volcanogenic acid addition, with the Vitric sites being generally more affected. Prolonged acid inputs have led to a general pH decrease and reduced exchangeable base cation concentrations in the Andosols. The concentrations of 0.5 M NH{sub 4}F- and 0.016 M KH{sub 2}PO{sub 4}-extractable sulfate (NH{sub 4}F-S and KH{sub 2}PO{sub 4}-S, respectively) indicate that volcanic S addition has increased the inorganic sulfate content of the Vitric and Eutric soils at all depths. In this process, the rate of sulfate accumulation is also dependent on soil allophane contents. For all soils, NH{sub 4}F extracted systematically more (up to 40 times) sulfate than KH{sub 2}PO{sub 4}. This difference suggests sulfate incorporation into an aluminum hydroxy sulfate phase, whose contribution to total inorganic sulfate in the Vitric and Eutric Andosols is estimated from {approx}34 to 95% and {approx}65 to 98%, respectively. The distribution of KH{sub 2}PO{sub 4}-extractable chloride in the Vitric and Eutric Andosols exposed to volcanic Cl inputs reveals that added chloride readily migrates through the soil profiles. In contrast, reaction of fluoride with Al and Fe oxyhydroxides and allophanes is an important sink mechanism in the Masaya Andosols exposed to airborne volcanic F. Fluoride dominates the anion distribution in all soil horizons, although F is the least concentrated element in the volcanic emissions and depositions. The soil anion

  2. Sulfate, chloride and fluoride retention in Andosols exposed to volcanic acid emissions

    The continuous emissions of SO2, HCl and HF by Masaya volcano, Nicaragua, represent a substantial source of atmospheric S-, Cl- and F-containing acid inputs for local ecosystems. We report on the effects of such acid depositions on the sulfate, chloride and fluoride contents in soils (0-40 cm) from two distinct transects located downwind from the volcano. The first transect corresponds to relatively undifferentiated Vitric Andosols, and the second transect to more weathered Eutric Andosols. These soils are exposed to various rates of volcanogenic acid addition, with the Vitric sites being generally more affected. Prolonged acid inputs have led to a general pH decrease and reduced exchangeable base cation concentrations in the Andosols. The concentrations of 0.5 M NH4F- and 0.016 M KH2PO4-extractable sulfate (NH4F-S and KH2PO4-S, respectively) indicate that volcanic S addition has increased the inorganic sulfate content of the Vitric and Eutric soils at all depths. In this process, the rate of sulfate accumulation is also dependent on soil allophane contents. For all soils, NH4F extracted systematically more (up to 40 times) sulfate than KH2PO4. This difference suggests sulfate incorporation into an aluminum hydroxy sulfate phase, whose contribution to total inorganic sulfate in the Vitric and Eutric Andosols is estimated from ∼34 to 95% and ∼65 to 98%, respectively. The distribution of KH2PO4-extractable chloride in the Vitric and Eutric Andosols exposed to volcanic Cl inputs reveals that added chloride readily migrates through the soil profiles. In contrast, reaction of fluoride with Al and Fe oxyhydroxides and allophanes is an important sink mechanism in the Masaya Andosols exposed to airborne volcanic F. Fluoride dominates the anion distribution in all soil horizons, although F is the least concentrated element in the volcanic emissions and depositions. The soil anion distribution reflects preferential retention of fluoride over sulfate and chloride, and of

  3. Current techniques in acid-chloride corrosion control and monitoring at The Geysers

    Hirtz, Paul; Buck, Cliff; Kunzman, Russell

    1991-01-01

    Acid chloride corrosion of geothermal well casings, production piping and power plant equipment has resulted in costly corrosion damage, frequent curtailments of power plants and the permanent shut-in of wells in certain areas of The Geysers. Techniques have been developed to mitigate these corrosion problems, allowing continued production of steam from high chloride wells with minimal impact on production and power generation facilities.The optimization of water and caustic steam scrubbing, steam/liquid separation and process fluid chemistry has led to effective and reliable corrosion mitigation systems currently in routine use at The Geysers. When properly operated, these systems can yield steam purities equal to or greater than those encountered in areas of The Geysers where chloride corrosion is not a problem. Developments in corrosion monitoring techniques, steam sampling and analytical methodologies for trace impurities, and computer modeling of the fluid chemistry has been instrumental in the success of this technology.

  4. Uranium, thorium and rare earth extraction and separation process by processing their chloride aqueous solutions

    The different steps of the process are the following: uranium and iron extraction by a neutral organic phosphorus compound and thorium and rare earth recovery in an aqueous solution, iron recovery in acid aqueous phase, concentration of the thorium and rare earth aqueous solution followed by thorium extraction with a organic phosphorus compound and rare earth recovery in the aqueous phase, thorium recovery in acid aqueous phase

  5. Studies of Tc oxidation states in humic acid solutions

    The oxidation state of Tc is an important aspect of the speciation in groundwater which contained organic substances due to it control the precipitation, complexation, sorption and colloid formation behavior of the Tc under HWL geological disposal conditions. In present work, the oxidation states of Tc were investigated using the LaCl3 coagulation method and solution extraction method in aqueous solutions in which the humic acid concentration range is from 0 to 20 mg/L and the Tc (VII) concentration is about 10-8 mol/L. The radiocounting of 99Tc was determined using liquid scintillation spectrometry. The humic acid will influence the radiocounting ratio of 99Tc apparently, however, the quenching effect can be restrained once keep the volume of the cocktail to about twenty times of the sample volume. The LaCl3 coagulation method was carried out for the investigation of Tc oxidation states in humic acid aqueous systems at about pH 8. The tetraphenylarsonium chloride (TPA)-chloroform extraction method was used also simultaneously to investigation the concentrations of Tc (IV) and Tc (VII) for the availability of the LaCl3 precipitation method, and the experimental results demonstrate that tetravalent technetium and pertechnetate concentration are well agreement with the LaCl3 precipitation method. These two experimental results demonstrated that Tc (VII) is very stable in the Tc (VII)-humic acid system during a 350 days experimental period, and the Tc (IV) concentrations are very lower, that is indicate that there didn't oxidizing reactions between the Fluka humic acid and Tc (VII) in aqueous solutions under anaerobic conditions. That means the presence of humic acids even in anaerobic groundwater is disadvantage for the retardance of radionuclides. (authors)

  6. Low temperature fatigue behavior of Alloy 600 in sodium chloride solution

    Fatigue crack growth (FCG) rates of mill annealed Alloy 600 in NaCl solution were studied by a fracture mechanics test method. Compact tension (CT) specimens were tested under load control with a sinusoidal wave form, in accordance with ASTM specification E647-83, to investigate the effects of environment, load frequency (f), load ratio (R = Pmin/Pmax). The FCG rates of Alloy 600, R = 0.1, f = 1Hz, were quite similar in air, distilled water, and NaCl (0.6M, 0.1M, and 0.001M) solution at room temperature. Environmental enhancement effect on the FCG rate of Alloy 600 was not significant in NaCl solution. Variations of the load frequency (0.03Hz--3Hz) did not influence the FCG rates of Alloy 600 significantly in air and 0.1M NaCl solution. The FCG rates of Alloy 600 in air and 0.1M NaCl solution increased with increasing the load ratio. Compared with the corrosion effects, test results showed that the mechanical effects dominated on the FCG rates of Alloy 600 in chloride solution at room temperature. The SEM fractographs showed that significant striations and transgranular fracture modes were observed on tested specimens

  7. Fatigue behavior of alloy 600 in sodium chloride solution at room temperature

    Fatigue crack growth (FCG) rates of mill annealed Alloy 600 in NaCI solution were studied by a fracture mechanics test method. Compact tension (CT) specimens were tested under load control with a sinusoidal wave form, in accordance with ASTM specification E647-83, to investigate the effects of environment, load frequency (f), load ratio (R=Pmin/Pmax). The FCG rates of Alloy 600, R=0.1, f=1Hz, were quite similar in air, distilled water, and NaCI (0.6 M, 0.1 M, and 0.001 M) solution at room temperature. Environmental enhancement effect on the FCG rate of Alloy 600 was not significant in NaCI solution. Variations of the load frequency (0.03Hz-3Hz) did not influence the FCG rates of Alloy 600 significantly in air and 0.1 M NaCI solution. The FCG rates of Alloy 600 in air and 0.1 M NaCI solution increased with increasing the load ratio. Compared with the corrosion effects, test results showed that the mechanical effects dominated on the FCG rates of Alloy 600 in chloride solution at room temperature. The SEM fractographs showed that significant striations and transgranular fracture modes were observed on tested specimens. (author)

  8. DILUTE SOLUTION BEHAVIOR OF CHITOSAN IN DIFFERENT ACID SOLVENTS

    WANG Wei; WANG Lihua; QIN Wen

    1994-01-01

    Dilute solution behavior of chitosan was studied in formic acid, acetic acid,lactic acid and hydrochloric acid aqueous solution under different pH values. The reduced viscosities, ηsp/C,of chitosan solutions were dependent on the properties of acid and pH value of solvents. For a given chitosan concentration, ηsp/C decreased with the increase of acid concentration, or decreasing pH of solvent, indicating shielding effect of excessive acid similar to adding salt into solution. The stabilities of dilute chitosan solution in formic acid and lactic acid were better than that in acetic acid and hydrochloric acid.

  9. Ruthenium nitrosyl complexes in nitric acid solutions

    Nine nitrosyl ruthenium complexes have been separated and identified in aqueous solutions of nitric acid. The separation method was low temperature, gradient elution, reverse phase partition chromatography using tri-n-butyl phosphate on a kiesel gel 60 support using 106Ru labelled complexes in the nitric acid phase. The identification of the complexes was deduced from the relationships between the products of aquation and nitration and paper chromatography using both methyl-iso-propyl ketone and nitric acid-acetone elutions. The proportion of each complex at equilibrium in various concentrations of nitric acid have been measured. The rates of nitration in 10 M nitric acid, and of aquation in 0.45 M nitric acid have been determined at 00C. (author)

  10. Stability of buprenorphine, haloperidol and glycopyrrolate mixture in a 0.9% sodium chloride solution.

    Jäppinen, A; Kokki, H; Naaranlahti, T J; Rasi, A S

    1999-12-01

    Combinations of opioids and adjuvant drug solutions are often used in clinical practice while little information is available on their microbiological or chemical stability. Currently there are no commercially available, prepacked, ready-to-use epidural or subcutaneous mixtures. Thus, epidural and subcutaneous analgesic mixtures must be prepared in the pharmacy on an as-needed basis. Such mixtures are typically used for the treatment of severe pain in cancer patients. The aim of this study was to investigate the microbiological and chemical stability of a buprenorphine, haloperidol and glycopyrrolate mixture in a 0.9% sodium chloride solution. A high performance liquid chromatographic (HPLC) method and pH-meter were used to conduct the analyses. Antimicrobial activity of each component was studied by an agar dilution method. According to the results from the chemical and microbiological stability studies, this mixture can be stored in polypropylene (PP) syringes and polyvinyl chloride (PVC) medication cassettes for at least 30 days at either 21 degrees C or 4 degrees C, and for 16 days in PP syringes at 36 degrees C, and for 9 days in PVC medication cassettes at 36 degrees C. PMID:10658237

  11. Effect of thermal aging on corrosion resistance of C-22 alloy in chloride solutions

    Alloy 22 (N06022) belongs to the Ni-Cr-Mo family and it is highly resistant to localized corrosion. The anodic behavior of mill annealed (MA) and thermally aged (10 hours at 760 C degrees) Alloy 22 was studied in chloride solutions with different pH values at 90 C degrees. Thermal aging leads to a microstructure of full grain boundary precipitation of topologically closed packed (TCP) phases. Electrochemical tests included monitoring of open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy. Assessment of general and localized (crevice) corrosion was performed. Re passivation potentials were obtained from cyclic potentiodynamic polarization tests. Results indicate that MA and TCP material show similar general corrosion rates and crevice corrosion resistance in the tested environments. MA and TCP specimens suffered general corrosion in an active state when tested in low pH chloride solutions. The grain structure of the alloy was revealed for MA material, while TCP material suffered a preferential attack at grain boundaries. (author)

  12. Determination of γ-spectrometric parameters for some chloride salt solutions

    The mass attenuation coefficients, atomic cross-sections and effective atomic numbers are determined for LiCl, NaCl and KCl solutions with contents up to 0.2 g cm-3.The energies used are 0.511, 0.662 and 1.274 keV. The combined results were employed to determine the mass attenuation coefficients and atomic cross-sections of the salts and water in the solutions. The results are compared with the calculated values from elemental data. It was found that the mass attenuation coefficients and corresponding total cross-sections are, in general, less from measurement than from tabulated data, either for water or for the chloride salts

  13. Anodic dissolution and corrosion of Cu30Ni alloys in chloride solutions

    Anodic and corrosion behaviour of Cu30Ni alloy in 3n. NaCl+0.01n. HCl solution is studied by radiometric method using 58Co gamma-isotopes (as an alien label for nickel) and 64Cu ones in combination with electrochemical measurements. It is ascertained that under stationary conditions both in the process of anodic dissolution and corrosion the alloy dissolves gradually. Partial anodic polarization dissolution curves of the alloy components are obtained. It is shown that kinetics of their dissolution differs from dissolution regularities of the corresponding pure metals. During the alloy corrosion in oxygen atmoshere the reverse precipitation of copper on the alloy surface is absent. The mentioned peculiarities in corrosion-electrochemical behaviour of the alloy in a concentrated chloride solution are explained by the presence of nickel on the surface of the dissolving alloy

  14. Extraction studies of cobalt (Ⅱ) and nickel (Ⅱ) from chloride solution using PC88A

    LUO Lin; WEI Jian-hong; WU Gen-yi; F. TOYOHISA; S. ATSUSHI

    2006-01-01

    Solvent extraction study of cobalt and nickel were carried out from a chloride solution with a high ratio of Co to Ni using the sodium salt of PC88A as extractant diluted in kerosene. The solution was generated in batches by leaching a tungsten super alloy scraps. The results show that extraction rate of metal ions increases with increase of aqueous phase pH value. The pH0.5 value difference of 1.40 with PC88A indicates the possible separation of cobalt and nickel. Increase of the concentration of the solvent can enhance the percentage extraction of both metal ions. Improvement of temperature is beneficial to extraction separation of cobalt and nickel. Extraction and stripping processes were also studied in a cross-current solvent extraction unit and the results were also given.

  15. Speciation of Tc(IV) in chloride solutions by capillary electrophoresis

    A method for speciation of Tc(IV) species (TcCl62- and TcCl5(H2O)-) in chloride solutions, using capillary electrophoresis (CE) technique was developed. The proposed method has overcome the difficulties of unstable oxidation states analysis by shortening their travel time in the capillary. TcCl62- and TcCl5(H2O)- were thus separated without being hydrolyzed and polymerized, and their UV/Vis spectra were recorded. With a 1 M HCl/NaCl buffer solution (pH = 1), the electrophoretic mobilities were determined as 5.47 x 10-4 cm2/Vs for TcCl62- and 2.13 x 10-4 cm2/Vs for TcCl5(H2O)- at 25 C. The total analysis time for one run is 12 minutes. (orig.)

  16. Corrosion performance of SiCsubp/6061 Al metal matrix composites in sodium chloride solution

    The corrosion performance of silicon carbide particle/aluminium metal matrix composites (SiCsubp/Al) were studied in sodium chloride solution by means of electrochemical, microscopic, gravimetric and analytical techniques. The materials under investigation were compocasting processed 6061 Al reinforced with increasing amounts of SiC particles. Potentiostatic polarization tests were done in 0.1M NaCl solutions that were aerated or deaerated to observe overall corrosion behaviour. It was seen that the corrosion potentials did not vary greatly in relation to the amounts of SiCsubp reinforcement. Corrosion tests showed that the degree of corrosion increased with increasing SiCsubp content. SEM analysis technique was used to study the corroded samples and the pitting morphology. By TEM, no intermetallic layer was found at SiC/Al interface. A model for pitting process was proposed

  17. Conductivity and Viscosity Measurements for Binary Lysozyme Chloride Aqueous Solution and Ternary Lysozyme-Salt-Water Solution

    Buzatu, D; Buzatu, F D

    2004-01-01

    We use the conductimetric method, adequate to electrolytes, to determine the lysozyme charge in lys-water and ternary lys-salt-water systems. We measured also the viscosities for the above binary and ternary systems in the same conditions at pH$=4.5$ and T$=298$ K, measurements that allow us to see any effect of viscosity on cations mobilities and implicitly on the lysozyme charge. The method is illustrated for the lysozyme chloride aqueous solution system at 25$^o$ C, using the data reported here for pH$=4.5$ at 0.15, 0.6, 0.8, 1., 1.5, 2., 2.5, 3., 3.5 mM (mg/mL) lysozyme chloride concentrations. The method was also applied to ternary lys-salt-water systems in the same conditions at pH$=4.5$ and T$=25^o$ C. Ternary conductivities are reported for a mean concentration 0.6 mM of lysozyme chloride in all systems and a mean concentration 0.01, 0.025, 0.05, 0.1, 0.175, 0.2, 0.5, 0.7, 0.9, 1.2, 1.3 and 1.4 M for NaCl; 0.005, 0.01, 0.05, 0.1, 0.175, 0.2, 0.5, 0.7, 0.9, 1.2, 1.3, 1.4 and 1.5 M for KCl; 0.005, 0.01,...

  18. Separation of platinum and rhodium from chloride solutions containing aluminum, magnesium and iron using solvent extraction and precipitation methods.

    Raju, B; Kumar, J Rajesh; Lee, Jin-Young; Kwonc, Hyuk-Sung; Kantam, M Lakshmi; Reddy, B Ramachandra

    2012-08-15

    The solvent extraction and precipitation methods have been used to develop a process to separate platinum and rhodium from a synthetic chloride solutions containing other associated metals such as (mg/L): Pt-364, Rh-62, Al-13880, Mg-6980, Fe-1308 at chloride ([Pt(tu)(4)]Cl(2)). The selective precipitation of rhodium was performed with (NH(4))(2)S from platinum free raffinate with a recovery of >99%. PMID:22664260

  19. Enhanced corrosion resistance of magnesium alloy AM60 by cerium(III) in chloride solution

    Heakal, F. El-Taib, E-mail: fakihaheakal@yahoo.com [Chemistry Department, Faculty of Science, Cairo University, Giza 12613 (Egypt); Shehata, O.S. [Physical Chemistry Department, National Research Centre, Dokki, Giza (Egypt); Tantawy, N.S. [Girl' s College of Arts, Science and Education, Ain Shams University, Asma Fahmi Street, Cairo (Egypt)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Corrosion rate of AM60 in Cl{sup -} solution decreases with increasing [Ce{sup 3+}] up to 1 mM. Black-Right-Pointing-Pointer Beyond that level the corrosion rate increases and then stabilizes. Black-Right-Pointing-Pointer The spontaneously formed film characterises by increasing resistance with time. Black-Right-Pointing-Pointer The converted film after 10 d immersion exhibits self-healing in plain Cl{sup -} solution. Black-Right-Pointing-Pointer Ce(III) should be present in the corrodent to form a more compact surface coating. - Abstract: Cerium(III) was utilised to enhance the corrosion resistance of AM60 in NaCl solution. Ce{sup 3+} can suppress corrosion deterioration up to 1.0 mM. Beyond that level corrosion rate increases till a steady value. Surface film resistance increases with time evolution until 24 h, then decreases and stabilizes. The converted film after 240 h immersion exhibits self-healing and thickening when re-exposed to plain chloride solution. SEM and EDX confirmed that when Ce is present as additive in solution, more compact coating is formed better than its presence as a post coating on the alloy surface before being immersed in the corrosive environment.

  20. Kinetics of Sawdust Hydrolysis with Dilute Hydrochloric Acid and Ferrous Chloride

    袁传敏; 颜涌捷; 任铮伟; 李庭琛; 曹建勤

    2004-01-01

    With dilute hydrochloric acid as catalyst and promoted by ferrous chloride, hydrolysis of waste sawdust to produce monosaccharides was conducted by using an one-step method in a batch-wise operation reactor. Based on the model of first order consecutive irreversible reactions, the kinetics equation incorporating the term of catalyst concentration was obtained that is suitable for describing the hydrolysis of sawdust. Activation energies were calculated for hydrolysis of sawdust and decomposition of monosaccharides.

  1. Novel 5-substituted benzyloxy-2-arylbenzofuran-3-carboxylic acids as calcium activated chloride channel inhibitors

    Kumar, Satish; Namkung, Wan; A S Verkman; Sharma, Pawan K

    2012-01-01

    Transmembrane protein 16A (TMEM16A) channels are recently discovered membrane proteins that functions as a calcium activated chloride channel (CaCC). CaCCs are major regulators of various physiological processes, such as sensory transduction, epithelial secretion, smooth muscle contraction and oocyte fertilization. Thirty novel 5-substituted benzyloxy-2-arylbenzofuran-3-carboxylic acids (B01–B30) were synthesized and evaluated for their TMEM16A inhibitory activity by using short circuit curre...

  2. Influence of flexural fatigue on chloride threshold value for the corrosion of steels in Ca(OH){sub 2} solutions

    Jiang, Linhua, E-mail: hhulhjiang@gmail.com [College of Mechanics and Materials, Hohai University, 1 Xikang Rd., Nanjing, 210098 (China); Hydraulic Engineering Research Center for New Materials and Protection, Jiangsu Province, 1 Xikang Rd., Nanjing, 210098 (China); Liu, Hao; Wang, Yongliang; Zhang, Yan; Song, Zijian; Xu, Jinxia; Jin, Ming; Jiang, Peng; Xu, Yi; Gao, Hailang [College of Mechanics and Materials, Hohai University, 1 Xikang Rd., Nanjing, 210098 (China)

    2015-08-15

    The flexural fatigue was enforced on reinforced concrete beam with stress level of 0.6 and different fatigue life cycles. Steels removed from the beams were soaked in the saturated Ca(OH){sub 2} solution, which was used as a simulated concrete pore solution. The NaCl solution was chosen as the source of chloride ions. The Chloride Threshold Values (CTV) were detected by combining the open-circuit potentials (E{sub corr}) with the corrosion current densities (i{sub corr}), which were obtained by electrochemical impedance spectroscopy (EIS). The changes of microstructure caused by the flexural fatigue were observed by scanning electron microscopy (SEM). The results showed that as the fatigue cycle times increased, the CTV decreased under a certain stress level and range of fatigue life cycles. The grains became finer and cracks appeared on the surface of the steels. While the capacitive arcs under no flexural fatigue decreased gradually with the addition of chloride ions, the ones under flexural fatigue presented no regularity. Cracks at the surface were expanded because of sustaining flexural fatigue, which degenerated the later resistance to chloride ions of the steels. - Highlights: • The influence of flexural fatigue on chloride threshold value was examined. • The chloride threshold values vary with different fatigue life cycles. • The corrosion behavior depends on the surface integrity of the steels.

  3. Influence of flexural fatigue on chloride threshold value for the corrosion of steels in Ca(OH)2 solutions

    The flexural fatigue was enforced on reinforced concrete beam with stress level of 0.6 and different fatigue life cycles. Steels removed from the beams were soaked in the saturated Ca(OH)2 solution, which was used as a simulated concrete pore solution. The NaCl solution was chosen as the source of chloride ions. The Chloride Threshold Values (CTV) were detected by combining the open-circuit potentials (Ecorr) with the corrosion current densities (icorr), which were obtained by electrochemical impedance spectroscopy (EIS). The changes of microstructure caused by the flexural fatigue were observed by scanning electron microscopy (SEM). The results showed that as the fatigue cycle times increased, the CTV decreased under a certain stress level and range of fatigue life cycles. The grains became finer and cracks appeared on the surface of the steels. While the capacitive arcs under no flexural fatigue decreased gradually with the addition of chloride ions, the ones under flexural fatigue presented no regularity. Cracks at the surface were expanded because of sustaining flexural fatigue, which degenerated the later resistance to chloride ions of the steels. - Highlights: • The influence of flexural fatigue on chloride threshold value was examined. • The chloride threshold values vary with different fatigue life cycles. • The corrosion behavior depends on the surface integrity of the steels

  4. Densitometry and ultrasound velocimetry of hyaluronan solutions in water and in sodium chloride solution.

    Kargerová, A; Pekař, M

    2014-06-15

    The densities of hyaluronan solutions in water and 0.15M NaCl were measured in the temperature range from 25 to 50°C for the hyaluronan molecular weights from 10 to 1,750 kDa. The density increased linearly with concentration and decreased with temperature. The data were fitted by the equation describing the density as a linear function of concentration and a quadratic function of temperature. The effect of molecular weight was negligible and thus single equation was sufficient to describe all data. The apparent and partial specific volumes were calculated from the density data including their extrapolated values to infinite dilutions. The measurement of ultrasound speed in the same solutions under the same conditions enabled to calculate the compressibility and its dependence on concentration and temperature. The compressibility decreased with both the concentration and the temperature but the effect of the concentration was only slight mild. The compressibility was used to estimate the hydration numbers which slightly decreased with increasing temperature and concentration. The addition of NaCl changed only the numerical values of density and ultrasound velocity while not changing the character of their dependence on temperature and concentration. Measured and calculated data indicate that hyaluronan does not disturb the specific water structure in the studied concentration range and support the idea of the existence of water clusters or nanodroplets hydrating the hyaluronan chains in solution. PMID:24721101

  5. Recovery of oxalate from scrubbing solution containing rare earths and iron produced during uranium recovery from phosphoric acid

    In this paper a method has been described to recover oxalate from oxalic acid containing iron. The process involves the adjusting the pH of the solution, adding calcium chloride 100% excess than stoichiometric amount and digesting the slurry for 2 hours followed by filtration. The calcium oxalate is decomposed with sulphuric acid to obtain gypsum and oxalic acid. The acid is recycled for scrubbing of iron

  6. Particle-induced x-ray emission: Instrumentation, calibration, and application to contact lens solutions and fulvic acid solutions

    An expression was derived describing the profile of the proton beam at the PIXE target position. The expression was used to predict the profile for several experimental configurations. The profile was experimentally measured. The PIXE system was calibrated using solutions and commercial foils. Experimental data was adjusted for all absorbers and interferences, and a quadratic relationship was determined relating calibration factor and atomic number for each series of X-ray transitions. Calibration factors were determined for all elements above aluminum, for both a pinhole filter and a 14-mil mylar filter. A group of contact lens solutions was analyzed using PIXE, ICP, and ISE. A digestion method was developed for removal. of chloride ion. Cluster analysis was used to classify the data. A commercial humic acid was separated into three fractions. The fulvic acid was characterized, and separations of metal-fulvic acid complexes from metal ions in solution were attempted using ultrafiltration

  7. Particle-induced x-ray emission: Instrumentation, calibration, and application to contact lens solutions and fulvic acid solutions

    Jenson, D.D.

    1989-01-01

    An expression was derived describing the profile of the proton beam at the PIXE target position. The expression was used to predict the profile for several experimental configurations. The profile was experimentally measured. The PIXE system was calibrated using solutions and commercial foils. Experimental data was adjusted for all absorbers and interferences, and a quadratic relationship was determined relating calibration factor and atomic number for each series of X-ray transitions. Calibration factors were determined for all elements above aluminum, for both a pinhole filter and a 14-mil mylar filter. A group of contact lens solutions was analyzed using PIXE, ICP, and ISE. A digestion method was developed for removal. of chloride ion. Cluster analysis was used to classify the data. A commercial humic acid was separated into three fractions. The fulvic acid was characterized, and separations of metal-fulvic acid complexes from metal ions in solution were attempted using ultrafiltration.

  8. Corrosion of alloy 22 in phosphate ions effect and chloride containing solutions

    Alloy 22 belongs to Ni-Cr-Mo family. This alloy resists the most aggressive environments for industrial applications, in oxidizing as well as reducing conditions, because exhibits an excellent uniform and localized corrosion resistance in aqueous solution. Because of its outstanding corrosion resistant, this alloy is one of the candidate to be considered for the outer shell of the canister that would contain high level radioactive nuclear wastes in a geological repository. The aim of this work is to study ion phosphate influence over Alloy 22 corrosion behavior under aggressive conditions, such as high temperature and high ion chloride concentration, where this material might be susceptible to crevice corrosion. Two different types of samples were used: cylinder specimens for uniform corrosion behavior studies and Prismatic Crevice Assembly (PCA) specimens for localized corrosion studies. Electrochemical tests were performed in deaerated aqueous solution of 1 M NaCl and 1 M NaCl with different phosphate additions at 90 C degrees and pH near neutral. The anodic film and corrosion products obtained were studied by SEM/EDS. Cyclic Potentiodynamic Polarization (CPP) curves obtained for uniform corrosion studies, showed an increase of the passivity range in phosphate containing solutions. The passive current value was 1 μA/cm2 approximately in all the tests. PCA electrochemical tests, that combined a CPP with a potentiostatic polarization step for 2 hours in between the forward and reverse scan, showed crevice corrosion development in some cases. The repassivation potential value, determined by the intersection of the forward and the reverse scan, increased with phosphate addition. A complete crevice corrosion inhibition effect was found for phosphate concentration higher than 0.3 M. These results indicate that the passivity potential range depend on phosphate presence and might be related with the incorporation of the anion in the passive film. Results of the tests

  9. Participation of GABAA Chloride Channels in the Anxiolytic-Like Effects of a Fatty Acid Mixture

    Juan Francisco Rodríguez-Landa

    2013-01-01

    Full Text Available Human amniotic fluid and a mixture of eight fatty acids (FAT-M identified in this maternal fluid (C12:0, lauric acid, 0.9 μg%; C14:0, myristic acid, 6.9 μg%; C16:0, palmitic acid, 35.3 μg%; C16:1, palmitoleic acid, 16.4 μg%; C18:0, stearic acid, 8.5 μg%; C18:1cis, oleic acid, 18.4 μg%; C18:1trans, elaidic acid, 3.5 μg%; C18:2, linoleic acid, 10.1 μg% produce anxiolytic-like effects that are comparable to diazepam in Wistar rats, suggesting the involvement of γ-aminobutyric acid-A (GABAA receptors, a possibility not yet explored. Wistar rats were subjected to the defensive burying test, elevated plus maze, and open field test. In different groups, three GABAA receptor antagonists were administered 30 min before FAT-M administration, including the competitive GABA binding antagonist bicuculline (1 mg/kg, GABAA benzodiazepine antagonist flumazenil (5 mg/kg, and noncompetitive GABAA chloride channel antagonist picrotoxin (1 mg/kg. The FAT-M exerted anxiolytic-like effects in the defensive burying test and elevated plus maze, without affecting locomotor activity in the open field test. The GABAA antagonists alone did not produce significant changes in the behavioral tests. Picrotoxin but not bicuculline or flumazenil blocked the anxiolytic-like effect of the FAT-M. Based on the specific blocking action of picrotoxin on the effects of the FAT-M, we conclude that the FAT-M exerted its anxiolytic-like effects through GABAA receptor chloride channels.

  10. Phytic Acid and Sodium Chloride Show Marked Synergistic Bactericidal Effects against Nonadapted and Acid-Adapted Escherichia coli O157:H7 Strains.

    Kim, Nam Hee; Rhee, Min Suk

    2016-02-01

    The synergistic antimicrobial effects of phytic acid (PA), a natural extract from rice bran, plus sodium chloride against Escherichia coli O157:H7 were examined. Exposure to NaCl alone at concentrations up to 36% (wt/wt) for 5 min did not reduce bacterial populations. The bactericidal effects of PA alone were much greater than those of other organic acids (acetic, citric, lactic, and malic acids) under the same experimental conditions (P 7-log CFU/ml reduction). Flow cytometry confirmed that PA disrupted the cell membrane to a greater extent than did other organic acids, although the cells remained viable. The combination of PA and NaCl induced complete disintegration of the cell membrane. By comparison, none of the other organic acids acted synergistically with NaCl, and neither did NaCl-HCl solutions at the same pH values as the test solutions of PA plus NaCl. These results suggest that PA has great potential as an effective bacterial membrane-permeabilizing agent, and we show that the combination is a promising alternative to conventional chemical disinfectants. These findings provide new insight into the utility of natural compounds as novel antimicrobial agents and increase our understanding of the mechanisms underlying the antibacterial activity of PA. PMID:26637600

  11. Mechanism of extraction of scandium by alkyl phosphoric acids from concentrated hydrochloric acid solutions

    The methods of saturation and molar ratios, radiometry and infrared spectroscopy have been used to investigate the mechanism of extraction of scandium with di(2-ethylhexyl) phosphoric acid from concentrated chloride solutions (8 M/l HCl). It is shown that the extraction is based on cation-exchange and solvation mechanisms. The results of quantitative estimate of the extraction are given. At HCl concentration below 2 M/l, Sc is extracted by the cation-mechanism. As the concentration of the acid increases, extraction through solvation increases too, while that through cation exchange decreases. At HCl concentration of 5 M/l, both mechanisms play an equal role in the extraction of Sc

  12. Prediction of Swelling Behavior of N-Isopropylacrylamide Hydrogels in Aqueous Solution of Sodium Chloride

    许小平; 李忠琴; 黄兴华; 王绪绪; 付贤; HiitherAndreas; MaurerGerd

    2004-01-01

    In this paper, a model is presented to correlate and predict the swelling behavior of hydrogels in aqueous solutions of electrolytes. The model is a combination of VERS-model, "phantom network" theory and "free-volume" contribution. The VERS-model is used to calculate Gibbs excess energy; "phantom network" theory to describe the elastic properties of polymer network, and "free-volume" contribution to account for additional difference in the size of the species. To test the model, a series of N-isopropylacrylamide based hydrogels are synthesized by free radical polymerization in oxygen-free, deionized water at 25~C under nitrogen atmosphere. Then, the degree of swelling of all investigated gels as well as the partition of the solute between the gel phase and the surrounding coexisting liquid phase are measured in aqueous solution of sodium chloride. The model test demonstrates that the swelling behavior correlated and predicted by the model agrees with the experimental data within the experimental uncertainty. The phase transition appeared in the experiment, and the influences of the total mass fraction of polymerizable materials ξgel as well as the mole fraction of the crosslinking agent YCR on the swelling behavior of IPAAm-gels can also be predicted correctly. All these show the potential of such model for correlation and prediction of the swelling behavior of hydrogels in aqueous solutions of electrolytes.

  13. Formation of linear polyenes in poly(vinyl alcohol) films catalyzed by phosphotungstic acid, aluminum chloride, and hydrochloric acid

    Tretinnikov, O. N.; Sushko, N. I.; Malyi, A. B.

    2016-07-01

    Formation of linear polyenes-(CH=CH)n-via acid-catalyzed thermal dehydration of polyvinyl alcohol in 9- to 40-µm-thick films of this polymer containing hydrochloric acid, aluminum chloride, and phosphotungstic acid as dehydration catalysts was studied by electronic absorption spectroscopy. The concentration of long-chain ( n ≥ 8) polyenes in films containing phosphotungstic acid is found to monotonically increase with the duration of thermal treatment of films, although the kinetics of this process is independent of film thickness. In films containing hydrochloric acid and aluminum chloride, the formation rate of polyenes with n ≥ 8 rapidly drops as film thickness decreases and the annealing time increases. As a result, at a film thickness of less than 10-12 µm, long-chain polyenes are not formed at all in these films no matter how long thermal duration is. The reason for this behavior is that hydrochloric acid catalyzing polymer dehydration in these films evaporates from the films during thermal treatment, the evaporation rate inversely depending on film thickness.

  14. Palladium-Catalyzed Multicomponent Synthesis of 2-Imidazolines from Imines and Acid Chlorides

    Boran Xu

    2012-11-01

    Full Text Available We describe the palladium-catalyzed multicomponent synthesis of 2-imidazolines. This reaction proceeds via the coupling of imines, acid chlorides and carbon monoxide to form imidazolinium carboxylates, followed by a decarboxylation. Decarboxylation in CHCl3 is found to result in a mixture of imidazolinium and imidazolium salts. However, the addition of benzoic acid suppresses aromatization, and generates the trans-disubstituted imidazolines in good yield. Combining this reaction with subsequent nitrogen deprotection provides an overall synthesis of imidazolines from multiple available building blocks.

  15. Synthesis of N-Acylated Amino Acid Surfactant from L-Proline and Palmitoyl Chloride

    A biodegradable, less toxic and environmentally friendly N-acylated amino acid surfactant was prepared from the amino acid L-proline and palmitoyl chloride through acylation reaction using the Schotten-Baumann reaction condition. The reaction result was a white flake form and the percentage of the crude yield was 72 % with melting point in range of 52 - 58 degree Celsius. Functional group of amide which was detected using Fourier Transform Infrared method showed the presence of N-palmitoyl proline. The purity analysis using High Performance Liquid Chromatography and Thin Layer Chromatography showed the result was a mixture compound. (author)

  16. Repassivation potentials determination of crevice corrosion of alloy in Chloride solutions

    Alloy 22 (UNS N06022) belongs to the Ni-Cr-Mo family and it is highly resistant to general and localized corrosion, but it may suffer crevice corrosion in aggressive environmental conditions, such as high chloride concentration, high applied potential and high temperature. Alloy 22 is one of the candidates to be considered for the outer corrosion-resistant shell of high-level nuclear waste containers. It is assumed that localized corrosion will only occur when the corrosion potential (ECORR) is equal or higher than the crevice corrosion repassivation potential (ER,CREV). This parameter is obtained by different electrochemical techniques using artificially creviced specimens. These techniques include cyclic potentiodynamic polarization (CPP) curves, Tsujikawa-Hisamatsu electrochemical (THE) method or other non-standardized methods. Recently, as a variation of THE method, the PD-GS-PD technique was introduced. The aim of the present work was to determine reliable critical potentials for crevice corrosion of Alloy 22 in pure chloride solutions at 90 C degrees. Conservative methodologies (which include extended potentiostatic steps) were applied for determining protection potentials below which crevice corrosion cannot initiate and propagate. Results from PD-GS-PD technique were compared with those from these methodologies in order to assess their reliability. Results from the CPP and the THE methods were also considered for comparison. The repassivation potentials from the PD-GS-PD technique were conservative and reproducible, and they did not depend on the amount of previous crevice corrosion propagation in the studied conditions. (author)

  17. Interfacial behavior of perchlorate versus chloride ions in saturated aqueous salt solutions

    Ghosal, S; Kuo, I W; Baer, M D; Bluhm, H

    2009-04-14

    In recent years combination of theoretical and experimental work have presented a novel view of the aqueous interface wherein hard and/or multiply charged ions are excluded from the interface, but large polarizable anions show interfacial enhancement relative to the bulk. The observed trend in the propensity of anions to adsorb at the air/water interface appears to be reverse of the Hofmeister series for anions. This study focuses on experimental and theoretical examination of the partitioning behavior of perchlorate (ClO{sub 4}{sup -}) and chloride (Cl{sup -}) ions at the air/water interface. We have used ambient pressure X-ray photoelectron spectroscopy technique to directly probe the interfacial concentrations of ClO{sub 4}{sup -} and Cl{sup -} ions in sodium perchlorate and sodium chloride solutions, respectively. Experimental observations are compared with first principles molecular dynamics simulations. Both experimental and simulation results show enhancement of ClO{sub 4}{sup -} ion at the interface, compared with the absence of such enhancement in the case of Cl{sup -} ion. These observations are in agreement with the expected trend in the interfacial propensity of anions based on the Hofmeister series.

  18. EVOLUTION OF THE ELECTROCHEMICAL CHARACTERISTICS DURING PITTING CORROSION OF PURE ALUMINUM IN SODIUM CHLORIDE SOLUTION

    Z. Zhang; C. Cai; F.H. Cao; Z.N. Gao; J.Q. Zhang; C.N. Cao

    2005-01-01

    The corrosion behavior of pure aluminum in neutral 3.0% (mass fraction) sodium chloride (NaCl) solution has been studied using electrochemical impedance spectroscopy (ELS) measurement in conjunction with the scanning electron microscopy (SEM) technique. EIS information on the evolution of pitting corrosion over a period of 15 days has been obtained and analyzed with equivalent circuit technique. The results shown that, during the ensemble constant immersion time, two time constants involved, the high frequency one originated from the protective layer on the corroding surface while the low frequency one from the diffusion process or the corrosion reaction and so on. And there existed a period for oxide film to growth and thickening prior to the commencement of the attacking of chloride ions to the substrate. Meanwhile, good relationship between EIS and the material corrosion type/severity has been obtained, which has been interpreted according to the characteristics of corrosion process such as auto acceleration of pitting corrosion and the protection of local anodic reaction to the area around them.

  19. Sulfate, chloride and fluoride retention in Andosols exposed to volcanic acid emissions.

    Delmelle, Pierre; Delfosse, Thomas; Delvaux, Bruno

    2003-01-01

    The continuous emissions of SO(2), HCl and HF by Masaya volcano, Nicaragua, represent a substantial source of atmospheric S-, Cl- and F-containing acid inputs for local ecosystems. We report on the effects of such acid depositions on the sulfate, chloride and fluoride contents in soils (0-40 cm) from two distinct transects located downwind from the volcano. The first transect corresponds to relatively undifferentiated Vitric Andosols, and the second transect to more weathered Eutric Andosols. These soils are exposed to various rates of volcanogenic acid addition, with the Vitric sites being generally more affected. Prolonged acid inputs have led to a general pH decrease and reduced exchangeable base cation concentrations in the Andosols. The concentrations of 0.5 M NH(4)F- and 0.016 M KH(2)PO(4)-extractable sulfate (NH(4)F-S and KH(2)PO(4)-S, respectively) indicate that volcanic S addition has increased the inorganic sulfate content of the Vitric and Eutric soils at all depths. In this process, the rate of sulfate accumulation is also dependent on soil allophane contents. For all soils, NH(4)F extracted systematically more (up to 40 times) sulfate than KH(2)PO(4). This difference suggests sulfate incorporation into an aluminum hydroxy sulfate phase, whose contribution to total inorganic sulfate in the Vitric and Eutric Andosols is estimated from approximately 34 to 95% and approximately 65 to 98%, respectively. The distribution of KH(2)PO(4)-extractable chloride in the Vitric and Eutric Andosols exposed to volcanic Cl inputs reveals that added chloride readily migrates through the soil profiles. In contrast, reaction of fluoride with Al and Fe oxyhydroxides and allophanes is an important sink mechanism in the Masaya Andosols exposed to airborne volcanic F. Fluoride dominates the anion distribution in all soil horizons, although F is the least concentrated element in the volcanic emissions and depositions. The soil anion distribution reflects preferential retention

  20. Sorption recovery of platinum (II, IV in presence of copper (II and zinc (II from chloride solutions

    Kononova Olga N.

    2015-01-01

    Full Text Available The sorption preconcentration of platinum (II, IV ions was investigated in presence of accompanying copper (II and zinc (II ions from chloride solutions on the new ion exchangers CYBBER (Russia, previously unexplored. The initial concentrations of platinum and accompanying ions were 0.25 mmol L-1 and 2.0 mmol L-1, respectively, and the acidity of medium was 0.001 - 4.0 mol L-1. It was shown that the resins investigated - strong and weak basic anion exchangers as well as chelate ion exchangers - possess good sorption and kinetic properties. The simultaneous sorption of investigated ions results in the complete recovery of platinum, while the non-ferrous metal ions are sorbed at less than 20%. Followed by the selective elution of platinum by thiourea (80 g L-1 solution in 0.3 M H2SO4, the quantitative isolation of platinum was achieved (more than 90%. Therefore, the studied ion exchangers can be recommended for recovery and separation of Pt(II,IV, Cu(II and Zn(II ions.

  1. Corrosion behaviour of Fe-Mn-Si-Al austenitic steel in chloride solution

    W. Krukiewicz

    2009-04-01

    Full Text Available Purpose: The aim of the paper is to investigate the corrosion behaviour of the new-developed high-manganese austenitic steel in 0.5n NaCl solution.Design/methodology/approach: The steel used for the investigation was thermomechanically rolled and solution heat-treated from a temperature of 850°C. Corrosion resistance of investigated steel was examined using weight and potentiodynamic methods. In the weight method, the specimens were immersed in the prepared solution for 24h. In the potentiodynamic method, anodic polarization curves with a rate of potential changes of 1 mV/s in the anodic direction were registered. After the current density being equal 1 mA/cm2 was achieved, the direction of polarization has been changed. Basing on the registered curves, the pitting potential, repassivation potential, polarization resistance and corrosion current were determined.Findings: It was found that the steel is characterized by a partially recrystallized austenitic microstructure with numerous annealing twins and slip bands. According to the results of potentiodynamic analyses it was found that the samples of examined steel show poor corrosion resistance in the NaCl solution. The observed corrosion pits are related to the chemical composition. It is connected with the high dissolution rate of Mn and Fe atoms in NaCl solution. Fractographic analyses of samples revealed corrosion products on their surface in a form of pits with diversified size.Research limitations/implications: To investigate in more detail the corrosion behaviour of high-manganese steel, the investigations should include steels with a wider Al concentration.Practical implications: The obtained results can be used for searching the appropriate way of improving the corrosion resistance of a modern group of high-manganese austenitic steels.Originality/value: The corrosion behaviour in chloride solution of a new-developed Fe-Mn-Si-Al steel was investigated.

  2. The study of method of removing chloride ion in the solution of MIPR (medical isotopes production reactor)

    By prepare the silver impregnated alumina adsorbents under the different ignition temperature to research and explore its capacity of remove chloride ions in this article. The result show the adsorbent can remove chloride ion effectively under the conditions of neutral at 700 degree C. And study the adsorbents' capacity of remove chloride ions and silver ions in nitric acid system. The result show that on 0.02 mol/L nitrate system the effect of Dechlorination column to remove the chloride ions is the best, and in the uranium samples in addition to the simulation the effect of in addition to Yinzhu to remove the silver ions is very good, almost all removed. (authors)

  3. ELECTROCHEMICAL NOISE ANALYSIS OF PURE ALUMINUM IN SODIUM CHLORIDE SOLUTION WITH WAVELET TRANSFORM TECHNIQUE

    Z. Zhang; Q.D. Zhong; J.Q. Zhang; Y.L. Cheng; F.H. Cao; J.M. Wang; C.N. Cao

    2002-01-01

    Wavelet transforms (WT) are proposed as an alternative tool to overcome the limita-tions of Fourier transforms (FFT) in the analysis of electrochemical noise (EN) data.The most relevant feature of this method of analysis is its capability of decomposingelectrochemical noise records into different sets of wavelet coefficients, which containinformation about the time scale characteristic of the associated corrosion event. Inthis context, the potential noise fluctuations during the free corrosion of pure alu-minum in sodium chloride solution was recorded and analyzed with wavelet transformtechnique. The typical results showed that the EN signal is composed of distinct typeof events, which can be classified according to their scales, i.e. their time constants.Meanwhile, the energy distribution plot (EDP) can be used as "fingerprints" of ENsignals and can be very useful for analyzing EN data in the future.

  4. Equilibrium studies of cobalt(II) extraction with 2-pyridineketoxime from mixed sulphate/chloride solution

    In present paper the equilibrium of cobalt extraction with 1-(2-pyridyl)tridecan-1-one oxime from the chloride/sulphate solutions was studied. The presented results indicated that extraction depends on a number of process variables, including the pH, metal and Cl- concentration in the aqueous feed, and concentration of the oxime in the organic phase. The created cobalt-complexes with the 2-pyridine ketoxime were stable and only concentrated HCl was found to be a suitable stripping agent for coordinated metal. The separation of Co(II) from Zn(II), Ni(II) and Cu(II) was also studied, but the selective recovery of the metals was possible using the multi-stage stripping process. (author)

  5. Pitting and crevice corrosion behaviour of high alloy stainless steels in chloride-fluoride solutions

    The localised corrosion resistance (pitting and crevice corrosion) of two high alloy stainless steels, namely superduplex (SD) and superaustenitic (SA), has been studied in chloride-fluoride solutions at pH values ranging from 2 to 6.5. The pitting potential (Epit) and crevice potential (Ecre) have been calculated for these test media using electrochemical techniques (continuous current). The critical pitting temperature (CPT) and critical crevice temperature (CCT) are in both materials lower then the room temperature. In spite of this fact and due to the high repassivation rate, the resistance of these materials to localised corrosion is high in the tested media. At the highest tested concentration of aggressive anions and pH 6.5 both materials undergo a generalised attack. (orig.)

  6. Analysis of corrosion behavior of LY12 in sodium chloride solution with wavelet transform technique

    张昭; 曹发和; 程英亮; 张鉴清; 王建明; 曹楚南

    2002-01-01

    Wavelet transforms(WT) are proposed as an alternative tool to overcome the limitations of fast Fourier transforms(FFT) in the analysis of electrochemical noise(EN) data. The most relevant feature of this method of analysis is its capability of decomposing electrochemical noise records into different sets of wavelet coefficients(distinct type of events), which contains information about the time scale characteristic of the associated corrosion event. In this context, the potential noise fluctuations during the free corrosion of commercial aluminum alloy LY12 in sodium chloride solution was recorded and analyzed with wavelet transform technique. The typical results show that the EN signal is composed of distinct type of events, which can be classified according to their scales, i.e. their time constants. Meanwhile, the energy distribution plot(EDP) can be used as "fingerprints" of EN signals and can be very useful for analyzing EN data in the future.

  7. Aromatic quinoxaline as corrosion inhibitor for bronze in aqueous chloride solution

    N Saoudi; A Bellaouchou; A Guenbour; A Ben Bachir; E M Essassi; M El Achouri

    2010-06-01

    A new corrosion inhibitor, viz. 3-ethyl-6-méthyl-quinoxalin-2-one, 1-benzyl-6-methyl-quinoxalin- 2-one, 2-benzyloxy-3,6-dimethyl-quinoxaline, 1-benzyl-3-methyl-quinoxalin-2-one, were synthesized in the laboratory. Their influence on the inhibition on corrosion of bronze in aqueous chloride solution (3% NaCl) was studied by electrochemical polarization methods and weight-loss measurements. The impact of temperature on the effectiveness of the substances mentioned above has been determined between 20 and 60°C. The results showed that the corrosion resistance was greatly enhanced in the presence of inhibitor and that the effectiveness depends on some physicochemical properties of the molecule, related to its functional groups. These compounds act through the formation of a protective film on the surface of the alloy.

  8. Metal lanolin fatty acid as novel thermal stabilizers for rigid poly(vinyl chloride)

    GUO Yong; ZHENG Yuying; QIU Shangchang; ZENG Anran; LI Baoming

    2011-01-01

    The synergistic stabilization effect of different metal lanolin fatty acids as natural-based thermal stabilizers for poly(vinyl chloride)(PVC) including calcium lanolin fatty acid (Calan2), zinc lanolin fatty acid (Znlan2) and lanthanum lanolin fatty acid (Lalan3) were studied through Congo red testing, color measurements, FTIR analyses and thermal behavior in this paper. The results showed that Lalan3/Calan2/Znlan2 stabilizers exhibited more excellent thermal stabilization efficiency to PVC than Calan2/Znlan2 thermal stabilizers, and the optimal mass ratio of Lalan3/Calan2/Znlan2 was 8:9:3. At last, the effect of degradation mechanism on PVC and synergistic stabilization was also investigated by FTIR analyses and thermal behavior.

  9. Sodium carboxymethylcellulose-induced aggregation of 1-decyl-3-methylimidazolium chloride in aqueous solutions.

    Ray, Dhiman; Das, Sourav; De, Ranjit; Das, Bijan

    2015-07-10

    Aggregation behavior of a surface active ionic liquid 1-decyl-3-methylimidazolium chloride (C10MeImCl) was studied in aqueous solutions in absence and in presence of sodium carboxymethylcellulose (NaCMC) by electrical conductivity, surface tension, vapor pressure, and fluorescence measurements. Ion-association behavior of C10MeImCl (aq) in the premicellar regime has also been investigated. Two characteristic concentrations, namely the critical aggregation concentration and polymer saturation concentration, before free C10MeImCl micelles appear in C10MeImCl-NaCMC solutions were identified. Effects of temperature, NaCMC concentration, and the bulk solution structural property on the self-aggregation of C10MeImCl have been discussed to elucidate C10MeImCl-NaCMC interactions. Thermodynamics of the micellization processes provided important insight regarding the (a) release of water molecules from the hydration layer around the hydrophilic domain, and from the water cage around the hydrophobic moiety of the SAIL, and (b) transfer of the hydrocarbon chains into the micelle and restoration of the H-bonding structure of the water around the micelle. PMID:25857982

  10. Alkaline earth cation extraction from acid solution

    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.

  11. Vanadium(5) sorption from weakly acid solutions

    Distribution of vanadium(5) between diluted solutions of sulfuric acid and macroporous polymer sorbent impregnated by a mixture of nitrogen-containing phenol-formaldehyde resol oligomer (R) and tributylphosphate has been studied. It has been ascertained that under the conditions mentioned vanadium transfers to solid phase as a mixture of chelates with stoichiometric ratio V:R = 1:1 and 2:1. During sorption by impregnated sorbent R capacity in terms of vanadium increases essentially as compared with solvent extraction

  12. Selective extraction of palladium with caffeine from acidic chloride media; Sansei enkabutsu yoeki karano kafuein ni yoru parajiumu no sentakuteki chushutsu

    Kaikake, K.; Baba, Y. [Miyazaki University, Miyazaki (Japan). Faculty of Engineering

    1999-06-10

    In order to examine the possibility of caffeine as an extractant, the extraction of metal ions from acidic chloride media was studied at 298 K using the mixture solvent of chloroform and 2-ethyl-1-hexanol. Caffeine has exhibited a high selectivity for palladium (2) over base metals such as copper (2), nickel (2), and iron (3), and over precious metal such as platinum (4). The stoichiometric relation in the extraction of palladium (2) with caffeine was elucidated by examining the effects of chloride ion, hydrogen ion, and caffeine concentrations on its extractability. In addition, palladium (2) was found to be extracted selectively with caffeine from the mixture containing a 25-fold amount of platinum (4) or copper (2). The stripping of palladium (2) was performed to an extent of 80% by a single batchwise treatment with an aqueous mixture solution of hydrochloric acid and thiourea. (author)

  13. Analysis of antibacterial efficacy of plasma-treated sodium chloride solutions

    Hänsch, Mareike A. C.; Mann, Miriam; Weltmann, Klaus-Dieter; von Woedtke, Thomas

    2015-11-01

    In this study, the change of chemical composition of sodium chloride solutions (NaCl, 0.85%) induced by non-thermal atmospheric pressure plasma (APP) treatment and subsequent effects on bacteria (Escherichia coli) are investigated. Besides acidification caused by APP, hydrogen peroxide (H2O2), nitrite (\\text{NO}2- ), and nitrate (\\text{NO}3- ) are generated as stable end-products of various chemical reactions in APP-treated liquids. Inactivation kinetics and reduction factors were recorded for E. coli (K12). Almost identical antimicrobial effects were observed with both direct APP exposure to bacteria suspension and exposure of APP-treated liquids to bacteria (indirect treatment). Consequently, main bactericidal effects are caused by chemical reactions which are mediated via the liquid phase. Moreover, APP-treated liquids have shown long-term activity (30 min) that possibly correlates with the ratio of \\text{NO}2- /H2O2. Therefore, \\text{NO}2- and H2O2 are identified as key agents for antimicrobial short- and long-term effects, respectively. The antimicrobial stability observed is strongly dependent on the used treatment regime and correlates additionally with the altered chemical composition of APP-treated liquids. Besides these effects, it was also shown that bacteria do not acquire resistance to such APP-treated solutions.

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

    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…

  15. Functional modifications of acid-sensing ion channels by ligand-gated chloride channels.

    Xuanmao Chen

    Full Text Available Together, acid-sensing ion channels (ASICs and epithelial sodium channels (ENaC constitute the majority of voltage-independent sodium channels in mammals. ENaC is regulated by a chloride channel, the cystic fibrosis transmembrane conductance regulator (CFTR. Here we show that ASICs were reversibly inhibited by activation of GABA(A receptors in murine hippocampal neurons. This inhibition of ASICs required opening of the chloride channels but occurred with both outward and inward GABA(A receptor-mediated currents. Moreover, activation of the GABA(A receptors modified the pharmacological features and kinetic properties of the ASIC currents, including the time course of activation, desensitization and deactivation. Modification of ASICs by open GABA(A receptors was also observed in both nucleated patches and outside-out patches excised from hippocampal neurons. Interestingly, ASICs and GABA(A receptors interacted to regulate synaptic plasticity in CA1 hippocampal slices. The activation of glycine receptors, which are similar to GABA(A receptors, also modified ASICs in spinal neurons. We conclude that GABA(A receptors and glycine receptors modify ASICs in neurons through mechanisms that require the opening of chloride channels.

  16. The vapour pressures over saturated aqueous solutions of cadmium chloride, cadmium bromide, cadmium iodide, cadmium nitrate, and cadmium sulphate

    Apelblat, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel)]. E-mail: apelblat@bgu.ac.il; Korin, Eli [Department of Chemical Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel)

    2007-07-15

    Vapour pressures of water over saturated solutions of cadmium salts (chloride, bromide, iodide, nitrate, and sulphate) were determined over the temperature range 280 K to 322 K and compared with the literature data. The vapour pressures determined were used to obtain the water activities, osmotic coefficients and the molar enthalpies of vaporization in the (cadmium salt + water) systems.

  17. The vapour pressures over saturated aqueous solutions of cadmium chloride, cadmium bromide, cadmium iodide, cadmium nitrate, and cadmium sulphate

    Vapour pressures of water over saturated solutions of cadmium salts (chloride, bromide, iodide, nitrate, and sulphate) were determined over the temperature range 280 K to 322 K and compared with the literature data. The vapour pressures determined were used to obtain the water activities, osmotic coefficients and the molar enthalpies of vaporization in the (cadmium salt + water) systems

  18. A Fiber-Optic Sensor Using an Aqueous Solution of Sodium Chloride to Measure Temperature and Water Level Simultaneously

    Wook Jae Yoo; Hyeok In Sim; Sang Hun Shin; Kyoung Won Jang; Seunghyun Cho; Joo Hyun Moon; Bongsoo Lee

    2014-01-01

    A fiber-optic sensor system using a multiplexed array of sensing probes based on an aqueous solution of sodium chloride (NaCl solution) and an optical time-domain reflectometer (OTDR) for simultaneous measurement of temperature and water level is proposed. By changing the temperature, the refractive index of the NaCl solution is varied and Fresnel reflection arising at the interface between the distal end of optical fiber and the NaCl solution is then also changed. We measured the modified ...

  19. Involvements of chloride ion in decolorization of Acid Orange 7 by activated peroxydisulfate or peroxymonosulfate oxidation

    Ping Wang; Shiying Yang; Liang Shan; Rui Niu; Xueting Shao

    2011-01-01

    The effects of chloride anion (C1-) (up to 1.0 mol/L) on the decolorization of a model compound,azo dye Acid Orange 7 (AO7),by sulfate radical (SO4-*) based-peroxydisulfate (PS) or peroxymonosulfate (PMS) oxidation under various activated conditions (UV254 nm/PS,Thermal (70℃/PS,UV254 nm/PMS,Co2+/PMS) were investigated.Methanol and NH4+ were used as quenching reagents to determine the contributions of active chlorine species (dichloride radical (Cl2-*) and hypochlorous acid (HClO)).The results indicated that the effects of Cl- on the reaction mechanism were different under various activated conditions.For UV/PS and Thermal/PS,the inhibition tendency became more clear as the Cl-concentration increased,probably due to the reaction between Cl- and SO4-* and the generation of Cl2-* or HClO.For UV/PMS,Cl- did not exhibit inhibition when the concentration was below 0.1 mol/L.As Cl-concentration reached to 1.0 mol/L,the decolorization rate of AO7 was,however,accelerated,possibly because PMS directly reacts with C1- to form HC1O.For Co2+/PMS,Cl- exhibited a significant inhibiting effect even at low concentration (≤ 0.01 mol/L).When Cl- concentration exceeded 0.1 mol/L,the activation of PMS by Co2+ was almost completely inhibited.Under this condition,HClO maybe played a major role in decolorization of AO7.The results implicated that chloride ion is an important factor in SO4-*-based degradation of organic contamination in chloride-containing water.

  20. Uranium adsorption from the sulphuric acid leach liquor containing more chlorides with cation-exchange resin SL-406

    The feasibility of uranium adsorption was studied from the sulphuric acid leach liquor of a uranium ore containing more chlorides with cation-exchange resin SL-406. The influence of some factors on uranium adsorption was investigated. It was shown that the resin possesses better selectivity, stability and higher capacity. It can be effectively used to recovery uranium from leach liquors of uranium ores containing more chlorides

  1. Uranyl fluoride luminescence in acidic aqueous solutions

    Luminescence emission spectra and decay rates are reported for uranyl species in acidic aqueous solutions containing HF or added NaF. The longest luminescence lifetime, 0.269 ± 0.006 ms, was observed from uranyl in 1 M HF + 1 M HClO4 at 296 K and decreased with increasing temperature. Based on a luminescence dynamics model that assumes equilibrium among electronically excited uranyl fluoride species and free fluoride ion, this long lived uranyl luminescence in aqueous solution is attributed primarily to UO2F2. Studies on the effect of added LiNO3 or Na2WO4·2H2O showed relatively weak quenching of uranyl fluoride luminescence which suggests that high sensitivity determination of the UF6 content of WF6 gas should be feasible via uranyl luminescence analysis of hydrolyzed gas samples of impure WF6

  2. Corrosion Study of Stainless Steels in Peracetic Acid Bleach Media With and Without Chloride and Chelant

    Rohtash

    2014-12-01

    Full Text Available The paper industries are adopting non-chlorine containing chemicals e.g. peroxide, ozone, peracids etc. as alternate of chlorine based bleach chemicals e.g. chlorine and chlorine dioxide etc. with the aim of eco-friend atmospheres. Changeover to the new chemicals in the bleaching process is likely to affect the metallurgy of the existing bleach plants due to change in the corrosivity of the media. Accordingly, corrosion investigations were performed in a peracid namely peracetic acid to test the suitability of austenitic stainless steels 654SMO, 265SMO, 2205, 317L and 316L. The performance of above stainless steels was evaluated through long term immersion tests and Electrochemical polarization measurements in peracetic acid (PAA bleach media at pH value 4 maintaining concentration 0.2 % as active oxygen along with three chloride levels 0, 500 and 1000 ppm in pulp-free laboratory. To study the effect of corrosion inhibitors with extending limit of chloride in liquors, measurements were also made with two types of chelants- EDTA & MgSO4. The results showed that corrosivity of PAA reduced by addition of chelant while increased with concentration of Cl¯. The results also exhibited that EDTA is better inhibitor than MgSO4.

  3. Localized corrosion of alloys C-276 and 625 in aerated sodium chloride solutions at 25 to 200 degrees C

    Two molybdenum-bearing nickel alloys, Alloy C-276 and Alloy 625, were previously identified for consideration as candidate container materials for the Canadian Nuclear Fuel Waste Management Program. Because of the paucity of data for the localized corrosion behaviour of these passive alloys under conditions that may be experienced in a disposal vault, this project was undertaken to study the crevice and pitting corrosion of Alloys C-276 and 625 in chloride solutions at elevated temperatures. Electrochemical and immersion tests have been conducted in neutral sodium chloride solutions (0.1 wt% to saturated) at 25 to 200 degrees C, in an attempt to identify the conditions under which localized corrosion occurs and to relate the actual corrosion behaviour to that expected on the basis of electrochemical studies. Cyclic polarization studies showed that the passivation breakdown potentials move rapidly to more active values with increasing temperatures. Above 100 degrees C the resistance to localized corrosion is greatly reduced. The results of the immersion tests are presented in the form of T versus (C1-) diagrams. These susceptibility diagrams suggest that there is a limiting crevice-corrosion temperature for each alloy in aerated, neutral sodium chloride solutions. Below this temperature corrosion does not occur, regardless of the chloride concentration. The values of the limiting crevice-corrosion temperatures were in the range 100 to 125 degrees C for Alloy C-276 and 100 to 115 degrees C for Alloy 625. Such values suggest that saturation of the chloride solutions by surface boiling could occur without the initiation of localized corrosion. These electrochemical results indicate that a large safety margin for susceptibility to localized corrosion might be found below 100 degrees C

  4. Evaluation and countermeasure of localized corrosion of stainless steels in neutral chloride solution environment

    It consists of the experimental conditions, the critical potential of crevice corrosion, in-situ measurement of the initiation behavior by Moire method, spontaneous potential (ESP) in the environment, addition of no effective anions for countermeasure of localized corrosion, and conclusions. The stainless steel type 304, 825, 625 and Ti are used as the samples and evaluated by the repassivation potential (ER,CREV) under some experimental conditions. The relation between ER,CREV and VCREV of type 444 in NaCl solution at 80 deg C showed two values were same. The growth behavior was affected largely by the potential values, concentration of NaCl, elements of alloys. Initiation and repassivation of crevice corrosion were controlled by addition of NO-3 and SO2-4. Relation between NM and ΔER,CREV/ΔT, some experimental conditions, profile of initiation-growth behavior of crevice corrosion of 18%Cr-14%Ni stainless steel, effects of alloy elements; P, Mn, Si and Cu on dissolution rate and ER,CREV of 18%Cr-14%Ni stainless steels, relation between ESP and O3 or residual chloride in seawater etc are illustrated. (S.Y.)

  5. The Influence of Calcium Chloride Salt Solution on the Transport Properties of Cementitious Materials

    Yaghoob Farnam

    2015-01-01

    Full Text Available The chemical interaction between calcium chloride (CaCl2 and cementitious binder may alter the transport properties of concrete which are important in predicting the service life of infrastructure elements. This paper presents a series of fluid and gas transport measurements made on cementitious mortars before and after exposure to various solutions with concentrations ranging from 0% to 29.8% CaCl2 by mass. Fluid absorption, oxygen diffusivity, and oxygen permeability were measured on mortar samples prepared using Type I and Type V cements. Three primary factors influence the transport properties of mortar exposed to CaCl2: (1 changes in the degree of saturation, (2 calcium hydroxide leaching, and (3 formation of chemical reaction products (i.e., Friedel’s salt, Kuzel’s salt, and calcium oxychloride. It is shown that an increase in the degree of saturation decreases oxygen permeability. At lower concentrations (~12%, the formation of chemical reaction products (mainly calcium oxychloride is a dominant factor decreasing the fluid and gas transport in concrete.

  6. Electrochemical noise characteristics in corrosion process of AZ91D magnesium alloy in neutral chloride solution

    ZHANG Li-jun; ZHU Xu-bei; ZHANG Zhao; ZHANG Jian-qing

    2009-01-01

    The corrosion process of AZ91D magnesium alloy in neutral 1% (mass fraction) sodium chloride aqueous solution was investigated by electrochemical noise(EN), SEM and EDX. Fractal theory was primarily used to depict the corrosion process of the alloy. The fast wavelet transform(FWT), as well as the fast Fourier transform(FFT), was employed to analyze the EN data. The results show that the overall corrosion process can be described by three stages. The first stage corresponds to the pit nucleation and growth; the second stage involves the growth of a passive oxide layer; and the third stage involves reactivation. With increasing immersion time, fractal dimension increases fast initially, fluctuates in the medium and increases again at last. Pitting corrosion and fractal dimension increase due to the initiation and formation of pits in the initial and the end of immersion, while depresses due to the passivation in the medium period. The results of SEM and EDX support the above conclusions.

  7. Ion flotation behaviour of thirty-one metal ions in mixed hydrochloric/nitric acid solutions.

    Hualing, D; Zhide, H

    1989-06-01

    The ion flotation of 31 metal ions in hydrochloric/nitric acid solution with the cationic surfactant cetylpyridinium chloride was investigated. A 25-ml portion of 0.27-2.87 x 10(-4)M metal ion and 1.8-6.0 x 10(-4)M cetylpyridinium chloride solution in 0.17-3.4M acid mixture ([HCl]:[HNO(3)] = 2.4:1) was subjected to flotation in a cell, 22.5 cm high and 4.0 cm in diameter, for 5 min, with nitrogen bubbles. Ir(IV), Pt(IV), Ge(IV), Sn(IV), Bi(III), Au(III), Tl(III), Pd(II) and Sn(II) were floated from solution in 95-100% yield; Ru(III), Rh(III), Ir(III), Hg(II), Ag(I) and Tl(I) were partly floated, while Cr(VI), Ti(IV), Zr(IV), Ga(III), In(III), Fe(III), Sb(III), Al(III), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), CD(II) and Pb(II) were floated with less than 20% yield. The flotation behaviour of these metal ions in the mixed acid system was compared with that in hydrochloric acid. The flotation is more efficient in the mixed acid system. PMID:18964771

  8. Effects of concentration of sodium chloride solution on the pitting corrosion behavior of AISI 304L austenitic stainless steel

    Asaduzzaman M.D.

    2011-01-01

    Full Text Available The pitting corrosion behavior of the austenitic stainless steel in aqueous chloride solution was investigated using electrochemical technique. Corrosion potential (Ecorr measurement, potentiodynamic experiments, potential-hold experiments in the passive range, and microscopic examination were used for the evaluation of corrosion characteristics. The experimental parameters were chloride ion concentration, immersion time and anodic-hold potential. Ecorr measurements along with microscopic examinations suggest that in or above 3.5 % NaCl at pH 2 pitting took place on the surface in absence of applied potential after 6 hour immersion. The potentiodynamic experiment reveals that Ecorr and pitting potential (Epit decreased and current density in the passive region increased with the increase of chloride ion concentrations. A linear relationship between Epit and chloride ion concentrations was found in this investigation. The analysis of the results suggests that six chloride ions are involved for the dissolution of iron ion in the pitting corrosion process of austenitic stainless steel.

  9. The effect of anions in the fluorimetric determination of uranium after extraction from acid-deficient aluminium nitrate solution

    The effect of perchlorate, chloride, sulphate, phosphate and fluoride on the fluorimetric determination of uranium after the extraction of uranium into methyl isobutyl ketone from acid-deficient aluminium nitrate solution has been established. Recoveries of uranium from perchlorate and sulphate media after addition of 1 ml of 15 M nitric acid are 100%. Chloride interferes, and a correction must be made to compensate for the anion effect. Phosphate and fluoride in amounts up to 25 mg give recoveries of at least 95%. The anion effect may be minimized by increasing the volume of the organic phase. (author)

  10. Calcium Chloride in Neonatal Parenteral Nutrition Solutions with and without Added Cysteine: Compatibility Studies Using Laser and Micro-Flow Imaging Methodology.

    Robert K Huston

    Full Text Available Previous studies of compatibility of calcium chloride (CaCl2 and phosphates have not included particle counts in the range specified by the United States Pharmacopeia. Micro-flow imaging techniques have been shown to be comparable to light obscuration when determining particle count and size in pharmaceutical solutions.The purpose of this study was to do compatibility testing for parenteral nutrition (PN solutions containing CaCl2 using dynamic light scattering and micro-flow imaging techniques.Solutions containing TrophAmine (Braun Medical Inc, Irvine, CA, CaCl2, and sodium phosphate (NaPhos were compounded with and without cysteine. All solutions contained standard additives to neonatal PN solutions including dextrose, trace metals, and electrolytes. Control solutions contained no calcium or phosphate. Solutions were analyzed for particle size and particle count. Means of Z-average particle size and particle counts of controls were determined. Study solutions were compared to controls and United States Pharmacopeia (USP Chapter 788 guidelines. The maximum amount of Phos that was compatible in solutions that contained at least 10 mmol/L of Ca in 2.5% amino acids (AA was determined. Compatibility of these solutions was verified by performing analyses of 5 repeats of these solutions. Microscopic analyses of the repeats were also performed.Amounts of CaCl2 and NaPhos that were compatible in solutions containing 1.5%, 2%, 2.5%, and 3% AA were determined. The maximum amount of NaPhos that could be added to TrophAmine solutions of > = 2.5% AA containing at least 10 mmol/L of CaCl2 was 7.5 mmol/L. Adding 50 mg/dL of cysteine increased the amount of NaPhos that could be added to solutions containing 10 mmol/L of CaCl2 to 10 mmol/L.Calcium chloride can be added to neonatal PN solutions containing NaPhos in concentrations that can potentially provide an intravenous intake of adequate amounts of calcium and phosphorus.

  11. Containment of nitric acid solutions of Plutonium-238

    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.

  12. Removal of blue 1 dye of aqueous solutions with a modified clay with iron chloride

    At the present time, several technologies have been proposed to remove dyes from water, adsorption is one of the most feasible methods and adsorbents with different properties, such as activated carbon, zeolites, clays and hydrogels among others. In this work, the sorption behavior of blue 1 dye by a natural clay from a site located in the Center-East of Mexico, and other modified with iron chloride were determined. The materials were characterized by X-ray diffraction to analyze its crystal structure, by scanning electron microscopy and elemental microanalysis of energy dispersive X-ray spectrometry to determine the composition and morphology, and the zero point charges were also determined to know the charge distribution on the surface of the clay. The ph effect, contact time, dye concentration and temperature were the parameters considered in this study. The results showed that clay does not suffer any important changes in its structure after the chemical treatments (modification with ferric chloride and contact with blue 1 solutions). The ph influences lightly the adsorption of the dye with natural clay, but the same effect is not observed in the ferric modified clay among the factor ph 6 and 8. The equilibrium time and the sorption capacity for natural clay were 48 hours and 6.16 mg/g, while for the ferric clay were 24 hours and 14.22 mg/g. Adsorption kinetics results were best adjusted to the pseudo first and pseudo second order models. Adsorption isotherms were best adjusted to the Langmuir model, indicating that both clays have a homogeneous surface. Thermodynamic parameters (E, ΔS and ΔG and ΔH) were calculated for the dye adsorption by the natural clay using data of the adsorption kinetics at temperatures between 20 and 50 C, indicating that the adsorption process is exothermic. For the case of ferric clay, it was not possible to calculate these thermodynamic parameters because the adsorption capacities were similar in the range of selected

  13. SYNTESIS OF THE COMPLEXES OF MACROPOROUS SULFONATED RESINS WITH FERRIC CHLORIDE AND THEIR CATALYTIC BEHAVIOR FOR SETERIFICATION OF ACETIC ACID WITH BUTANOL

    HuangWenqiang; HouXin; 等

    1997-01-01

    The complex resins prepared from macroporous sulfonated resin D72(H+ form) with ferric chloride or ferric chloride hexahydrate have both sites of Bronsted acid and Lewis acid.In the catalysis of exterification of acetic acid with butanol the complex resins show to have much higher catalytic activity than that of its matrix.a conventional sulfonated cation exchange resin D72.

  14. Investigation of the main chemical properties of water-magnesium chloride solutions. Application to the understanding of stress corrosion phenomena in 17.12 Mo stainless steel

    This research thesis reports the investigation of the main chemical properties of concentrated aqueous solutions of MgCl2 and of their influence of stress corrosion of 17Cr-12Ni-2Mo stainless steel. It shows that the most important chemical properties are the equilibrium pH and the acidity range of MgCl2 aqueous solutions, and that they strongly depend on solution temperature and concentration. The medium pH is governed by the increased acidity of water in presence of Mg++ ions, while the acidity range is determined by a hydrolysis reaction of these ions which results in a precipitation of magnesium hydroxyl-chlorides. The investigation of stress corrosion behaviour of the steel in MgCl2 solutions with varying temperature and concentration shows that this behaviour comes down to a prevailing pH effect which results from the variation of these both parameters, with a not negligible but less important effect of temperature. A study of cracking surfaces indicates that it is possible to pass from a transgranular to an intergranular mode by a variation of either media aggressiveness (pH, temperature, voltage) or strain rate. These results are explained by a concept of kinetic factor which limits stress corrosion

  15. Extraction of scandium from hydrochloric solutions by phosphinic acids

    Distribution of scandium between aqueous solutions of HCl and solutions of dioctyl- and diarylphosphinic acids in organic solvents and so acids containing two phosphoryl groups bonded by methylene fragment is investigated. Extraction ability with respect to scandium in hydrochloric acid media increases in dialkylphosphoric acid < dialkylphosphinic acid < diarylphosphinic acid row and with aryl substituent electronegativity increase. Increase of a number of phosphoryl groups in extractant molecule leads to increase of scandium extraction

  16. Antifungal activity of essential oils when associated with sodium chloride or fatty acids

    Tantatoui-Elaraki, Abdelthafour

    1994-12-01

    Full Text Available The inhibition of mycelium growth in a Zygorhynchus sp. and an Aspergillus niger isolates was studied. The inhibition rates (IR caused by 4 essential oils (EO, 5 fatty acids and sodium chloride at various concentrations were determined in Sabouraud Dextrose Agar.
    A synergy of action was observed between sodium chloride at 7.5% and the EO of thyme (0.04%, camomile (0.4% and mugwort (0.2 and 0.1% on A. niger and between sodium chloride (5% and the EO of camomile (0.1% and mugwort (0.1 and 0.01% and sodium chloride (7.5% and eucalyptus EO (0.4 and 0.2% on Zygorhynchus sp.
    Camomile EO (0.13% associated with propionic acid (0.075%, lauric acid (0.05% or oleic acid (0.15% led to synergetic effect on Zygorhynchus sp. as well as thyme EO (0.04 and 0.05%, respectively with propionic acid (0.1% and linolenic acid (0.075% on A. niger. Other combinations exerted no higher effects than each of the substances used alone.
    Practical applications of the results observed were discussed

    Se ha estudiado la inhibición del crecimiento miceliar en un aislamiento de Zygorhynchus sp. y otro de Aspergillus niger. Se determinaron las tasas (o índices de inhibición (IR en Agar Sabouraud Dextrosa provocados por varias concentraciones de 4 aceites esenciales (EG, 5 ácidos grasos y cloruro sódico.
    Se observó un efecto sinérgico entre cloruro sódico al 7.5% y los aceites esenciales de tomillo (0.04%, manzanilla (0.4% y artemisa (0.2 y 0.1% sobre A. niger, y entre cloruro sódico (5% y los aceites esenciales de manzanilla (0.1% y de artemisa (0.1 y 0.01%, así como cloruro sódico (7.5% y aceite esencial de eucalipto (0.4 y 0.2%, sobre Zygorhynchus sp.
    El aceite esencial de manzanilla (0.13% en asociación con ácido propiónico (0.075%, ácido láurico (0.05% o ácido oleico (0.15% provocó un efecto sinérgico sobre Zygorhynchus sp., de la misma forma

  17. Ion flotation as a method to concentrate diluted sulfuric acid uranium solution

    Possibility of flotation uranium extraction from diluted sulfuric-acid solutions of uranyl complexes by twoquarter ammonium and pyridine bases is stated experimentally. The maximal degree of flotation uranium extraction is attained in the pH 2-4 region by means of hexadecylpropyridine chloride and ethylenediammonium dichloride (1.2(-N, N'-bis(dimethyl)-N, N'-bis (decylacetate) and it is equal to 99%. The effect of temperature increase from 20 to 50 deg C is studied. Technological solutions of low-percent uranium ores have been simulated

  18. Passivation of duplex stainless steel in solutions simulating chloride-contaminated concrete

    Takenouti, H.

    2007-12-01

    Full Text Available Most studies published to date on the corrosion behaviour of stainless reinforcing steel are based on austenitic steel. The market presence of corrugated duplex steel is growing, however. The present study compared passivity in 2205 type duplex and 304 type austenitic stainless steel. Polarization tests in chloride-containing Ca(OH2 solutions confirmed the exceptional performance of duplex steels. X-ray photoelectronic spectroscopy (XPS showed that the passive layer generated on duplex stainless steel in media simulating concrete pore solutions had a higher Cr content than the layer formed on steel in contact with the air. The XPS results also revealed that in duplex steel the form adopted by the passive layer Fe oxides was Fe3O4 in the solutions simulating concrete, rather than Fe2O3, as in duplex steel exposed to air. Electrochemical impedance spectroscopy (EIS can be used to monitor the transformations taking place in the passive layer and analyze the factors involved.La mayoría de los estudios publicados hasta el momento sobre el comportamiento frente a la corrosión de armaduras de acero inoxidable se basan en aceros austeníticos. Sin embargo, la presencia en el mercado de aceros corrugados dúplex es cada vez más importante. En este trabajo se analiza la pasividad de un acero inoxidable dúplex tipo 2205 en comparación con la de un inoxidable austenítico tipo 304. Los ensayos de polarización en disoluciones de Ca(OH2 con cloruros confirman el excepcional comportamiento de los aceros dúplex. La espectroscopía fotoelectrónica de rayos X (XPS informa de que la capa pasiva generada en aceros inoxidables dúplex en medios que simulan la disolución de los poros del hormigón posee mayor contenido en óxidos de Cr que la formada en aire. También se puede deducir de los resultados de XPS que los óxidos de Fe de la capa pasiva de los aceros dúplex se encuentran en forma de Fe3O4 en las disoluciones que simulan el hormigón en vez de en

  19. Palladium-Catalyzed α-Arylation of Aryl Acetic Acid Derivatives via Dienolate Intermediates with Aryl Chlorides and Bromides

    Sha, Sheng-Chun; Zhang, Jiadi; Walsh, Patrick J.

    2015-01-01

    To date, examples of α-arylation of carboxylic acids remain scarce. Using a deprotonative cross-coupling process (DCCP), a method for palladium-catalyzed γ-arylation of aryl acetic acids with aryl halides has been developed. This protocol is applicable to a wide range of aryl bromides and chlorides. A procedure for the palladium-catalyzed α-arylation of styryl acetic acids is also described.

  20. Sodium Chloride Diffusion in Low-Acid Foods during Thermal Processing and Storage.

    Bornhorst, Ellen R; Tang, Juming; Sablani, Shyam S

    2016-05-01

    This study aimed at modeling sodium chloride (NaCl) diffusion in foods during thermal processing using analytical and numerical solutions and at investigating the changes in NaCl concentrations during storage after processing. Potato, radish, and salmon samples in 1% or 3% NaCl solutions were heated at 90, 105, or 121 °C for 5 to 240 min to simulate pasteurization and sterilization. Selected samples were stored at 4 or 22 °C for up to 28 d. Radish had the largest equilibrium NaCl concentrations and equilibrium distribution coefficients, but smallest effective diffusion coefficients, indicating that a greater amount of NaCl diffused into the radish at a slower rate. Effective diffusion coefficients determined using the analytical solution ranged from 0.2 × 10(-8) to 2.6 × 10(-8) m²/s. Numerical and analytical solutions showed good agreement with experimental data, with average coefficients of determination for samples in 1% NaCl at 121 °C of 0.98 and 0.95, respectively. During storage, food samples equilibrated to a similar NaCl concentration regardless of the thermal processing severity. The results suggest that sensory evaluation of multiphase (solid and liquid) products should occur at least 14 d after processing to allow enough time for the salt to equilibrate within the product. PMID:27060992

  1. Aqueous Solutions of the Ionic Liquid 1-butyl-3-methylimidazolium Chloride Denature Proteins

    Baker, Gary A [ORNL; Heller, William T [ORNL

    2009-01-01

    As we advance our understanding, ionic liquids (ILs) are finding ever broader scope within the chemical sciences including, most recently, pharmaceutical, enzymatic, and bioanalytical applications. With examples of enzymatic activity reported in both neat ILs and in IL/water mixtures, enzymes are frequently assumed to adopt a quasi-native conformation, even if little work has been carried out to date toward characterizing the conformation, dynamics, active-site perturbation, cooperativity of unfolding transitions, free energy of stabilization, or aggregation/oligomerization state of enzymes in the presence of an IL solvent component. In this study, human serum albumin and equine heart cytochrome c were characterized in aqueous solutions of the fully water-miscible IL 1-butyl-3-methylimidazolium chloride, [bmim]Cl, by small-angle neutron and X-ray scattering. At [bmim]Cl concentrations up to 25 vol.%, these two proteins were found to largely retain their higher-order structures whereas both proteins become highly denatured at the highest IL concentration studied here (i.e., 50 vol.% [bmim]Cl). The response of these proteins to [bmim]Cl is analogous to their behavior in the widely studied denaturants guanidine hydrochloride and urea which similarly lead to random coil conformations at excessive molar concentrations. Interestingly, human serum albumin dimerizes in response to [bmim]Cl, whereas cytochrome c remains predominantly in monomeric form. These results have important implications for enzymatic studies in aqueous IL media, as they suggest a facile pathway through which biocatalytic activity can be altered in these nascent and potentially green electrolyte systems.

  2. Calcium chloride and calcium bromide aqueous solutions of technical and analytical grade in Lemna bioassay.

    Vujević, M; Vidaković-Cifrek, Z; Tkalec, M; Tomíc, M; Regula, I

    2000-11-01

    Saturated water solutions of calcium chloride, calcium bromide and their 1:1 mixture are commonly used as "high density brines" for pressure control in oil wells. To compare the effect of these chemicals of technical grade with the effect of the chemicals of analytical grade the Lemna test was used. The multiplication rate, fresh weight, dry to fresh weight ratio, area covered by plants and chlorophyll content were measured as toxicity parameters. The concentrations of tested chemicals were 0.025, 0.05. 0.075 and 0.1 mol dm(-3). Generally, the chemicals of both technical and analytical grade in concentrations of 0.025 mol dm(-3) stimulated the Lemna minor growth, while tested chemicals in concentrations of 0.05 mol dm(-3) did not affect the growth significantly. The exceptions were results obtained by measuring fresh weight. Most of tested chemicals in concentrations of 0.075 mol dm(-3) and all chemicals in concentrations of 0.1 mol dm(-3) reduced the growth. No major differences between effects of tested chemicals of technical and analytical grade on plant growth were observed, except that tested chemicals of analytical grade in concentrations of 0.1 mol dm(-3) increased dry to fresh weight ratio much stronger than chemicals of technical grade. All tested chemicals in all concentrations increased chlorophyll content. After treatment with chemicals of analytical grade much higher increase of chlorophyll a concentration in comparison to increase of chlorophyll b was noticed, while chemicals of technical grade caused more prominent increase of chlorophyll b. PMID:11057678

  3. On the Stress Corrosion Cracking and Hydrogen Embrittlement Behavior of Austenitic Stainless Steels in Boiling Saturated Magnesium Chloride Solutions

    Alyousif, Osama M.; Rokuro Nishimura

    2012-01-01

    The stress corrosion cracking (SCC) and hydrogen embrittlement (HE) behaviors for types 304, 310, and 316 austenitic stainless steels were investigated in boiling saturated magnesium chloride solutions using a constant load method under different conditions including test temperature, applied stress, and sensitization. Both of type 304 and type 316 stainless steels showed quite similar behavior characteristics, whereas type 310 stainless steel showed a different behavior. The time to failure ...

  4. Stress corrosion cracking of 13% Cr martensitic steels in sodium chloride solutions in the presence of thiosulphate

    The stress corrosion cracking (SCC) susceptibility of 13% Cr martensitic (UNS S42000) and supermartensitic (UNS S41125) steels in sodium chloride solutions in the presence of thiosulphate was evaluated by slow strain rate tests (SSRT). The tests were performed in 5% sodium chloride solutions buffered at pH 2.7, 3.5, 4.5 and 6.0 in the absence and presence of thiosulphate in a concentration range between 10-6 and 10-3 M, at 25 ± 0.1 C. The electrochemical behaviour of the two steels in the different solutions was determined by recording the anodic and cathodic polarisation curves. 13% Cr martensitic steel showed SCC in 5% sodium chloride solutions with pH ≤ 4.5 in the presence of 3 x 10-6 thiosulphate. Decreasing the chloride ion concentration from 50 to 10 g/l, the critical concentration of thiosulphate to provoke SCC susceptibility increased from 3 x 10-6 to 1 x 10-5 M. The resistance to SCC of the supermartensitic steel was higher than that of the martensitic steel. The critical concentration of thiosulphate to induce SCC on the supermartensitic steel were 1 x 10-5 M at pH 2.7 and 1 x 10-4 M at pH 3.5. At pH ≥ 4.5 the supermartensitic steel did not crack. The anodic and cathodic polarisation curves evidenced the influence of the thiosulphate on the corrosion and the activation effect on the steels. The SCC of the two steels was attributed to hydrogen embrittlement produced by sulphur and hydrogen sulphide formed by dismutation and reduction of thiosulphate. (orig.)

  5. Comparison of the corrosion behavior and surface morphology of NiTi alloy and stainless steels in sodium chloride solution

    Kožuh S.; Vrsalović L.; Gojić M.; Gudić S.; Kosec B.

    2016-01-01

    The corrosion behavior of NiTi alloy and stainless steels (AISI 316L and X2CrNiMoN22-5-3) in 0.9% sodium chloride (0.154 moll-1) solution was investigated using open circuit potential measurements, potentiodynamic polarization and electrochemical impedance spectroscopy measurements. Microstructural analyses before and after electrochemical tests were performed with the scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS). Th...

  6. Stress corrosion cracking of nickel alloys in bicarbonate and chloride solutions

    Alloy 22 is one of the candidates for the manufacture of high level radioactive waste containers. These containers provide services in natural environments characterized by multi-ionics solutions, it is estimated they could suffer three types of deterioration: general corrosion, localized corrosion (crevice corrosion) and stress corrosion cracking (SCC). It has been confirmed that the presence of bicarbonate at temperatures above 60°C and applied potentials around +400 mVSCE are necessary in order to produce cracking, . This susceptibility may be associated to the instability of the passive film formed and to the formation of an anodic current peak in the polarization curves in these media. Until now, it is unclear the role played by each alloying element (Ni, Cr or Mo) in the SCC susceptibility of Alloy 22 in these media The aim of this work is to evaluate the SCC susceptibility of nickel-based alloys in media containing bicarbonate and chloride ions, at high temperature. Slow Strain Rate Testing (SSRT) was conducted to samples of different alloys: 22 (Ni-Cr-Mo), 600 (Ni-Cr-Fe), 800H (Ni-Fe-Cr) y 201 (99.5% Ni).This tests were conducted in 1.1 mol/L NaHCO3 +1.5 mol/L NaCl a 90°C and different applied potentials (+200mVSCE,+300 mVSCE, +400 mVSCE). These results were complemented with those obtained in a previous work, where we studied the anodic electrochemical behavior of nickel base alloys under the same conditions. It was found that alloy 22 showed a current peak in a potential range between +200 mVSCE and +300 mVSCE when immersed in bicarbonate ions containing solutions. This peak was attributed to the presence of chromium in the alloys. The SSRT showed that only alloy 22 has a clear indication of stress corrosion cracking. The current results suggested that the presence of an anodic peak in the polarization curves was not a sufficient condition for cracking. (author)

  7. The synergistic inhibition between 8-hydroxyquinoline and chloride ion for the corrosion of cold rolled steel in 0.5 M sulfuric acid

    The corrosion inhibition of cold rolled steel in 0.5 M sulfuric acid in the presence of 8-hydroxyquinoline and sodium chloride (NaCl) has been investigated by using weight loss and electrochemical techniques. The inhibition efficiency increases with increasing concentration of 8-hydroxyquinoline at the same temperature, but decreases with increasing temperature studied. A synergistic effect exists when 8-hydroxyquinoline and chloride ions are used together to prevent cold rolled steel corrosion in 0.5 M sulfuric acid at every experimental temperature. The polarization curves show that 8-hydroxyquinoline is a cathodic inhibitor, while the complex of 8-hydroxyquinoline and NaCl is a mixed-type inhibitor. The experimental results suggested that the presence of chloride ions in the solution stabilizes the adsorption of 8-hydroxyquinoline molecules on the metal surface and improved the inhibition efficiency of 8-hydroxyquinoline. The adsorption of single 8-hydroxyquinoline follows the Temkin adsorption isotherm, but the complex accords with the Langmuir adsorption isotherm. Some thermodynamic parameters such as adsorption heat, adsorption entropy and adsorption free energy have been calculated by employing thermodynamic equations. Kinetic parameters such as apparent activation energy and pre-exponential factor have been calculated and discussed

  8. Comparison of adsorptions by rice hull and Lewatit TP 214 of platinum in chloride solution

    Morcali M.H.

    2013-01-01

    Full Text Available Rice hull, a biomass waste product, and Lewatit TP 214, a thiosemicarbazide sorbent, were investigated as adsorbents for the adsorption of platinum (IV ions from synthetically prepared dilute chloroplatinic acid solutions. The rice hull was characterized by Attenuated Total Reflection-Fourier transform infrared spectroscopy (ATR-FTIR. The effects of the different adsorption parameters, sorbent dosage, contact time, temperature and pH of solution on adsorption percentage were studied in detail on a batch sorption. The adsorption equilibrium data were best fitted with the Langmuir isotherm model. The maximum monolayer adsorption capacities, Qmax, at 25°C were found to be 42.02 and 33.22 mg g-1 for the rice hull and Lewatit TP 214, respectively. Thermodynamic calculations using the measured ΔH°, ΔS° and ΔG° values indicate that the adsorption process was spontaneous and exothermic. The pseudo-first-order and pseudo-second-order rate equations were investigated; the adsorption of platinum ions for both sorbents was found to be described by the pseudo-second-order kinetic model. The kinetic rate, k2, using 30 mg sorbent at 25°C was found to be 0.0289 and 0.0039 g min-1 mg-1 for the rice hull and Lewatit TP 214, respectively. The results indicated that the rice hull can be effectively used for the removal of platinum from aqueous solution.

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

    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. Anion-exchange Studies of Radioactive Trace Elements in Sulphuric Acid Solutions

    As part of a chemical group separation procedure used as a pretreatment in gamma spectrometric analysis, a study has been made of the adsorption from sulphuric acid solutions on strongly basic anion exchange resins, prepared in the hydroxide and the sulphate forms, of trace activities of Na, P, K, Ca, Sc, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Zr, Nb, Mo, Tc, Ag, Cd, In, Cs, Ba, La, Ce, Hf, Ta, W, Ir, Pa and Np. Besides adsorbing some of the trace elements in the solution, the anion exchange resin in the hydroxide form will neutralize the bulk of the sulphuric acid. This makes possible the subsequent sequential separation of chloride complexes on short anion-exchange columns by a stepwise increasing of the HCl concentration of the solution. On the basis of the results obtained in the present and earlier experiments, a new improved chemical group-separation procedure for mixtures of radioactive trace elements is outlined

  11. Hydrometallurgical extraction of zinc from CaO treated EAF dust in ammonium chloride solution.

    Miki, Takahiro; Chairaksa-Fujimoto, Romchat; Maruyama, Katsuya; Nagasaka, Tetsuya

    2016-01-25

    Zinc in Electric Arc Furnace dust or EAF dust mainly exists as ZnFe2O4 and ZnO. While ZnO can be simply dissolved into either an acidic or alkaline solution, it is difficult to dissolve ZnFe2O4. In our previous work, we introduced a process called "CaO treatment", a preliminary pyrometallurgical process designed to transform the ZnFe2O4 in the EAF dust into ZnO and Ca2Fe2O5. The halogens and others heavy metals were favorably vaporized during CaO treatment with no essential evaporation loss of zinc and iron, leaving CaO treated dust which consisted mainly of ZnO and Ca2Fe2O5 and no problematic ZnFe2O4 compound. In this work, the selective leaching of zinc over iron and calcium in the CaO treated dust was investigated using an NH4Cl solution. The effects of temperature, reaction time and NH4Cl concentration on dissolution behavior were examined. While most of the zinc in the CaO treated dust was extracted after 2 h at 70 °C with 2 M NH4Cl, only about 20% of calcium was leached in NH4Cl solution. However, the iron did not dissolve and remained as Ca2Fe2O5 in residue. It was confirmed that zinc can be effectively recovered using NH4Cl solution. PMID:26448494

  12. Synergistic effect between cationic gemini surfactant and chloride ion for the corrosion inhibition of steel in sulphuric acid

    Qiu Lingguang [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China)], E-mail: lgqiu@ahu.edu.cn; Wu Yun; Wang Yimin; Jiang Xia [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China)

    2008-02-15

    Corrosion inhibition of cold rolled steel in 0.5 mol L{sup -1} sulphuric acid by a quaternary ammonium gemini surfactant, l,3-propane-bis(dimethyl dodecylammonium bromide) (designated as 12-3-12), in the absence and presence of chloride ions was investigated at different temperatures. The results revealed significant synergistic effect between gemini 12-3-12 and chloride ions for the corrosion protection of cold rolled steel in sulphuric acid, and that the novel composite inhibitor system containing cationic gemini surfactant and chloride ions was efficient and low-cost for steel corrosion inhibition in sulphuric acid medium, even when concentration of 12-3-12 was as low as 1 x 10{sup -6} mol L{sup -1}. By fitting the obtained experimental data with Langmuir adsorption model and Arrhenius equation, some thermodynamic and kinetic parameters such as adsorption free energy, the apparent activation energy, and the pre-exponential factor were estimated. The adsorption mechanism of the gemini surfactant onto steel surface in acid medium in the absence and presence of chloride ions was also discussed, respectively.

  13. Aerobic oxidation of benzylic aldehydes to acids catalyzed by iron (Ⅲ) meso-tetraphenylporphyrin chloride under ambient conditions

    2007-01-01

    Highly efficient aerobic oxidation of benzylic aldehydes to the corresponding acids catalyzed by iron (Ⅲ) meso-tetraphenylporphyrin chloride (Fe(TPP)Cl) under ambient conditions was developed. The catalyst has been proved to be an excellent catalyst for the system in the presence of molecular oxygen and isobutryaldehyde at room temperature.

  14. Influence of sodium chloride and weak organic acids (flux residues) on electrochemical migration of tin on surface mount chip components

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2013-01-01

    contamination. The probability of migration becomes less dependent on the amount of contamination for sodium chloride at high concentrations. However, for organic acids from flux residues the migration probability shows an abrupt decrease with increasing concentration, which is attributed to a pH change in the...

  15. Treatment of acidic mine water at uranium mine No. 711 by barium chloride-sludge recycle-fractional neutralization process

    The barium chloride-sludge recycle-fractional neutralization process for disposal of acidic mine water at Uranium Mine No. 711 was checked through laboratory and enlarged tests and one-year industrial trial-run. The results showed that the presented technology can meet the requirements of production and environmental protection

  16. Phase and extraction equilibria in water-polyethyleneglycol ethers of monoethanolamides of synthetic fatty acid-ammonium chloride systems

    Lesnov, A. E.; Golovkina, A. V.; Kudryashova, O. S.; Denisova, S. A.

    2016-08-01

    Phase equilibria in layering systems of water, polyethyleneglycol ethers of monoethanolamides of synthetic fatty acids (SFAs) (synthamide-5), and ammonium chloride are studied. The possibility of using such systems for the liquid extraction of metal ions is evaluated. The effect the nature of salting-out agents has on the processes of segregation of the systems has been considered.

  17. Functionalyzed Polyampholytes on the Basis of Copolymers of N,N-Diallyl-N,N-dimethylammonium Chloride and Maleic Acid

    Vlasov, Petr; Chernyy, Sergey; Domnina, Nina

    2010-01-01

    Polyampholytes were prepared by radical copolymerization of N,N-diallyl-N,N-dimethylammonium chloride and maleic acid. The esterification and subsequent hydrazinolysis permitted to introduce hydrazide groups capable of formation of the coordination bond with copper ions. The formation of complex ...

  18. Chemical behaviour of Np, Pu and Am in saline solutions: Radiolysis, solubility, hydrolysis, chloride complexation and speciation

    The assessment of the migration behaviour of actinide elements (Np, Pu, Am) in the geosphere requires detailed knowledge on basic geochemical reactions, which include not only primary reactions of actinides with groundwater components but also secondary reactions, such as radiolysis, redox reaction, colloid formation, etc. The radiolytic behaviour of Pu and Am has been investigated in solutions of high NaCl concentration, in which radiolysis reactions are induced by intensive α-radiations of actinides themselves. An increase in the redox potential (Eh) is observed in solutions, which results in the quantitative oxidation of Pu(IV) into Pu(VI) and Am(III) into Am(V). These reactions are dependent on pH, salinity and specific α-activity. The results of α-radiolysis are compared with the effect of γ-radiolysis on inactive chloride solutions. As Pu(VI) can be stabilized in concentrated NaCl solutions, indicating that chloride complexation of Pu(VI) is important, the chloride complexation is studied by spectrophotometry and the stability constants of the first two Pu(VI)-chloro complexes are determined. Solubility experiments of NpO2 and NpO2OH in concentrated saline solutions are carried out under aerobic and anaerobic atmosphere (90% Ar, 1% CO2). The speciation of soluble species is undertaken by UV-VIS-spectrophotometry. The experiment of the Am(III)-hydrolysis reaction has revealed a dependence of Am solubility on the specific α-activity. However, no alteration in the chemical state of hydrolysis products is observed in different specific α-activities. The speciation is carried out by laser induced photoacoustic spectroscopy (LPAS) because of the low Am(III) solubility at pH>7. (orig./RB)

  19. Selective extraction of palladium(II) ions from chloride solutions with pyridinecarboxamides

    A huge demand for noble metals, such as Pd(II), Ru(III), Rh(III), Pt(IV) etc., as value added components in metal alloys is observed. Solvent extraction is very suitable method for their recovery from low concentrated sources. The aim of presented work was to find the conditions for selective extraction with N-dodecylpyridine-3-carboxyamide (3-C12) and N-dodecylpyridine-4-carboxyamide (4-C12) of Pd(II) from hydrochloric acid solutions of various concentrations in the presence of Pb(II), Cu(II), Ni(II), Fe(III), Rh(III), Ru(III) or Pt(IV). It has been shown that N-alkylpyridinecarboxyamides are effective extractants in comparison with commercial chelating extractant ACORGA CLX50

  20. Solvent extraction of scandium by TBP from inorganic acid solutions

    Studied has been the distribution of scandium between the 100% TBP and the aqueous solutions of the nitric and hydrochloric acids with the various concentrations of scandium and acids. A relationship has been determined between the concentration constants of the scandium extraction from the solutions of the nitric, hydrochloric, sulfuric and chlorous acid solutions, the hydration energies of the extracting ions and the stability constants of the complexes, comprising scandium and anions

  1. Effects of dietary chromium chloride, nicotinic acid and copper sulphate on meat of broilers.

    Javed, M T; Ellahi, M; Abbas, N; Yasmin, R; Mazhar, M

    2010-06-01

    1. Combinations of chromium and copper were added to the diet to assess their effects on broiler meat characteristics. 2. For this purpose 175 one-day-old broiler chicks were divided into 7 equal groups and were given treatment feeds containing copper sulphate, chromium chloride and nicotinic acid in different combinations. 3. The study was carried out for 5 weeks and samples were collected at the end of 15, 29 and 35 d of treatment and at 42 d after a withdrawal period of one week. 4. Cholesterol content had decreased significantly in breast meat at d 29 in all treatment groups. In thigh meat, it decreased significantly at d 29 in groups receiving two concentrations of chromium + two concentrations of copper. Cholesterol content remained lower even after withholding the treatment for one week. 5. Crude fat content decreased significantly in breast meat in all treatment groups. In thigh meat, at d 29, a significant reduction in crude fat was observed only in birds receiving low chromium and high copper. 6. Crude protein at d 29 increased significantly in breast meat of birds receiving low chromium and high copper, and low or high chromium, while it decreased significantly in treatment groups after withholding the treatment. In thigh meat, at d 29, it increased significantly in treatment groups but decreased significantly after withholding the treatment. 7. It was concluded that chromium and copper, along with nicotinic acid, have modulating effects on broiler meat under tropical conditions. PMID:20680870

  2. Novel short chain fatty acids restore chloride secretion in cystic fibrosis

    Phenylalanine deletion at position 508 of the cystic fibrosis transmembrane conductance regulator (ΔF508-CFTR), the most common mutation in cystic fibrosis (CF), causes a misfolded protein exhibiting partial chloride conductance and impaired trafficking to the plasma membrane. 4-Phenylbutyrate corrects defective ΔF508-CFTR trafficking in vitro, but is not clinically efficacious. From a panel of short chain fatty acid derivatives, we showed that 2,2-dimethyl-butyrate (ST20) and α-methylhydrocinnamic acid (ST7), exhibiting high oral bioavailability and sustained plasma levels, correct the ΔF508-CFTR defect. Pre-incubation (≥6 h) of CF IB3-1 airway cells with ≥1 mM ST7 or ST20 restored the ability of 100 μM forskolin to stimulate an 125I- efflux. This efflux was fully inhibited by NPPB, DPC, or glibenclamide, suggesting mediation through CFTR. Partial inhibition by DIDS suggests possible contribution from an additional Cl- channel regulated by CFTR. Thus, ST7 and ST20 offer treatment potential for CF caused by the ΔF508 mutation

  3. Model investigations for trace analysis of iodine, uranium, and technetium in saturated sodium chloride leaching solutions of stored radioactive waste

    This paper describes the development of a time and cost saving chromatographic technique, which allows the matrix to be separated and the most important species to be analyzed in a leaching solution of vitrified radioactive waste. Uranium, iodine, and technetium were chosen for the model technique to be elaborated. In a first step, iodide and pertechnetate were separated from the matrix by the strongly basic AG 1X 8 anion exchange resin and then separated from each other by selective elution. The uranyl ions eluted with the sodium chloride matrix were separated from the excess of sodium chloride in a second step, again by adsorption to the strongly basic resin. The ion-selective electrode was found to be a suitable tool for iodide analysis. Pertechnetate was analysed by means of liquid scintillation. Uranium was determined by ICP-AES. (orig./RB)

  4. Infrared Spectroscopic Study of the Adsorption Forms of Cyanuric Acid and Cyanuric Chloride on TiO2.

    Chien, Tzu-En; Li, Kun-Lin; Lin, Po-Yuan; Lin, Jong-Liang

    2016-05-31

    Cyanuric acid is often found to be the end product in the hydrolysis of waste melamine and in the TiO2-mediated photocatalytic decomposition of s-triazine-containing compounds used as herbicides or dyes. The photocatalytically recalcitrant nature of cyanuric acid on TiO2 may be closely related to its adsorption properties, including the tautomeric forms present on the surfaces and their bonding structures, which remain to be determined. In this paper, we present the optimized adsorption structures of the four tautomeric isomers (triketo, diketo, monoketo, and triol) of cyanuric acid on a model rutile-TiO2(110) surface and their vibrational absorptions. Experimentally, the adsorption structures of cyanuric acid and chloride on powdered TiO2 are analyzed on the basis of the theoretically obtained, characteristic infrared information. Cyanuric acid on TiO2 at 35 °C exists in triketo and hydroxylated forms, but the diketo becomes the predominant form on the surface at 250 °C, being bonded to a titanium site via one of its carbonyl groups and with a N-H···O hydrogen bonding interaction. Hydroxylation of cyanuric chloride occurs as it is adsorbed on TiO2 at 35 °C. Upon being heated to 200 °C, the surface is mainly covered with the diketo form of cyanuric acid after the adsorption of cyanuric chloride. PMID:27176610

  5. Oral salt supplements to compensate for jejunostomy losses: comparison of sodium chloride capsules, glucose electrolyte solution, and glucose polymer electrolyte solution.

    Nightingale, J M; Lennard-Jones, J E; Walker, E. R.; Farthing, M J

    1992-01-01

    Six patients with jejunostomies and residual jejunal lengths of 105 to 250 cm took the same food and water each day for eight study days. In random order, three methods of salt replacement were tested, each over 48 hours, against a period without added salt. During the three test periods the patients took 120 mmol of sodium chloride daily, as salt in gelatine capsules, as an isotonic glucose electrolyte (280 mOsmol/kg; 30 kcal) solution, and as a glucose polymer (Maxijul) solution (280 mOsmol...

  6. Extraction of scandium by sorption from sulfuric acid solutions

    Ion-exchange resin to scandium extract from technical solution with a high salt background is selected. It is shown that scandium sorption ability on phosphoric acid resins from synthetic and technological sulphate solutions with the acidity of 1.8-3.8 n is the function of solution motion rate through the layer of resin and of the sorbent linkage degree. Sulfuric acid concentration in the range of 1.8-3.8 n does not affect the sorption ability of scandium. 2n solution of Na2CO3 is one of the most efficient eluents for scandium from phosphoric acid resin

  7. Containment of nitric acid solutions of Plutonium-238

    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. copyright 1999 American Institute of Physics

  8. Effects of temperature and pressure on stress corrosion cracking behavior of 310S stainless steel in chloride solution

    Zhong, Yunpan; Zhou, Cheng; Chen, Songying; Wang, Ruiyan

    2016-06-01

    310S is an austenitic stainless steel for high temperature applications, having strong resistance of oxidation, hydrogen embrittlement and corrosion. Stress corrosion cracking(SCC) is the main corrosion failure mode for 310S stainless steel. Past researched about SCC of 310S primarily focus on the corrosion mechanism and influence of temperature and corrosive media, but few studies concern the combined influence of temperature, pressure and chloride. For a better understanding of temperature and pressure's effects on SCC of 310S stainless steel, prepared samples are investigated via slow strain rate tensile test(SSRT) in different temperature and pressure in NACE A solution. The result shows that the SCC sensibility indexes of 310S stainless steel increase with the rise of temperature and reach maximum at 10MPa and 160°C, increasing by 22.3% compared with that at 10 MPa and 80 °C. Instead, the sensibility decreases with the pressure up. Besides, the fractures begin to transform from the ductile fracture to the brittle fracture with the increase of temperature. 310S stainless steel has an obvious tendency of stress corrosion at 10MPa and 160°C and the fracture surface exists cleavage steps, river patterns and some local secondary cracks, having obvious brittle fracture characteristics. The SCC cracks initiate from inclusions and tiny pits in the matrix and propagate into the matrix along the cross section gradually until rupture. In particular, the oxygen and chloride play an important role on the SCC of 310S stainless steel in NACE A solution. The chloride damages passivating film, causing pitting corrosion, concentrating in the cracks and accelerated SSC ultimately. The research reveals the combined influence of temperature, pressure and chloride on the SCC of 310S, which can be a guide to the application of 310S stainless steel in super-heater tube.

  9. Slow strain rate behavior of TiCode 12 (ASTM Gr.12) in aqueous chloride solutions

    Slow strain rate testing has shown that the macroscopic tensile properties of mill-annealed TiCode 12 are not affected by exposure to either a synthetic seawater or high chloride brine environment. However, microscopic examination indicates that the fracture mode may be sensitive to environment. This sensitivity appears to be related to hydrogen ingress during prolonged exposure

  10. Chemistry of ruthenium in nitric acid solution with special regard to nuclear fuel solutions

    A review is given concerning the published knowledge about the chemistry of ruthenium in nitric acid solution with special reference to nitric acid nuclear fuel solutions. Possibilities of the spectroscopic description of the different existing ruthenium complexes are discussed and papers are presented dealing with the estimation of the proportions of the different ruthenium compounds in nuclear fuel solutions. Finally, arguments are derived for the preparation of ruthenium-containing model solutions, which adequately simulate the composition of real nuclear fuel solutions. (author)

  11. Radiation protection by ascorbic acid in sodium alginate solutions

    Alginates are gelling hydrocolloids extracted from brown seaweed used widely in the nourishing and pharmaceutical industries. As alginic acid gellification retard food entrance in the stomach alginate is an additive used in diets. The objective of this work was to study the protective action of the ascorbic acid in alginate solutions against the action of 60 Co gamma radiation. One % (w/v) solutions of alginate had been used and concentrations of ascorbic acid varied from 0 to 2.5% (w/v). The solutions were irradiated with doses up to 10 kGy. Viscosity/dose relationship and the p H of the solutions at 25 Centigrade were determined. Ascorbic acid behaved as an antioxidant against radiation oxidative shock in this model system of an irradiated viscous solution. Besides its radiation protective role on alginate solutions ascorbic acid promoted a viscosity increase in the range of concentrations employed. (Author)

  12. Radiation protection by ascorbic acid in sodium alginate solutions

    Aliste, A.J.; Mastro, N.L. Del [Center of Radiation Technology, IPEN/CNEN/SP, University City, 05508-000 Sao Paulo (Brazil)]. E-mail: ajaliste@ipen.br

    2004-07-01

    Alginates are gelling hydrocolloids extracted from brown seaweed used widely in the nourishing and pharmaceutical industries. As alginic acid gellification retard food entrance in the stomach alginate is an additive used in diets. The objective of this work was to study the protective action of the ascorbic acid in alginate solutions against the action of {sup 60} Co gamma radiation. One % (w/v) solutions of alginate had been used and concentrations of ascorbic acid varied from 0 to 2.5% (w/v). The solutions were irradiated with doses up to 10 kGy. Viscosity/dose relationship and the p H of the solutions at 25 Centigrade were determined. Ascorbic acid behaved as an antioxidant against radiation oxidative shock in this model system of an irradiated viscous solution. Besides its radiation protective role on alginate solutions ascorbic acid promoted a viscosity increase in the range of concentrations employed. (Author)

  13. Development of a combined solution formulation of atropine sulfate and obidoxime chloride for autoinjector and evaluation of its stability.

    Ettehadi, Hossein Ali; Ghalandari, Rouhollah; Shafaati, Alireza; Foroutan, Seyed Mohsen

    2013-01-01

    Atropine (AT) and oximes, alone or in combination, have been proven greatly valuable therapeutics in the treatment of organophosphates intoxications. An injectable mixture of AT and obidoxime (OB) was formulated for the administration by automatic self-injector. The aqueous single dose solution contained 275 mg obidoxime chloride and 2.5 mg atropine sulfate per 1 mL (220 mg and 2 mg per 0.8 effective dose, respectively). The final solution was sterilized by filtration through a 0.22 μm pore size filter. This more concentrated solution allowed to use a smaller size and lighter weight cartridge. Quality control tests, including assay of the two major compounds were performed separately, using reversed-phase HPLC methods. Besides, the stability test was carried out according to ICH guideline for the accelerated test. The obtained results showed that the proposed formulation is stable over a period of 2 years after preparation. PMID:24250669

  14. The beneficial effect of ruthenium additions on the passivation of duplex stainless steel corrosion in sodium chloride solutions

    Sherif, El-Sayed M. [DST/NRF Centre of Excellence in Strong Materials, School of Physics, University of the Witwatersrand, Johannesburg, Wits 2050 (South Africa); Center of Excellence for Research in Engineering Materials (CEREM), College of Engineering, King Saud University, P. O. Box 800, Al-Riyadh 11421 (Saudi Arabia)], E-mail: esherif@ksu.edu.sa; Potgieter, J.H. [Chemistry and Materials Division, School of Biology, Chemistry and Health Sciences, Manchester Metropolitan University, Oxford Road, Manchester M1 5GD (United Kingdom); Comins, J.D. [DST/NRF Centre of Excellence in Strong Materials, School of Physics, University of the Witwatersrand, Johannesburg, Wits 2050 (South Africa); Cornish, L.; Olubambi, P.A.; Machio, C.N. [DST/NRF Centre of Excellence in Strong Materials, School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, Wits 2050 (South Africa)

    2009-06-15

    The effect of varying ruthenium contents of 0.00, 0.14, 0.22, and 0.28% on the corrosion of 22%Cr-9%Ni-3%Mo duplex stainless steel (DSS) after different immersion intervals in 3.5% NaCl solutions has been investigated. The study was carried out using open-circuit potential, potentiodynamic cyclic polarization, chronoamperometry, electrochemical impedance spectroscopy, and weight-loss measurements. Particular attention was paid to the effect of Ru on the pitting corrosion of DSS in the chloride solutions. Electrochemical measurements indicated that the presence of Ru passivates the DSS alloy by decreasing its corrosion parameters. Furthermore, it shifts the corrosion and pitting potentials to more positive values. This effect was found to increase with increasing Ru content and also with increased immersion time of the alloy in the chloride solution before measurements. Weight-loss time data after varied exposure periods (4-20 days) showed that the weight-loss and corrosion rate of DSS significantly decrease with increasing Ru contents.

  15. Electrical conductivity of aqueous solutions of perrhenic acid

    The physiocochemical properties of perrhenic acid, HReO4, are studied; its salts form the basis of solutions for electrochemical production of rhenium. Information is presented from which the electrical conductivity of solutions in the temperature range 15-90 degrees can be determined from known concentrations of the acid in water and vice versa

  16. Reaction of the rubidium peroxotungstate solutions with sulfuric acid

    The chemical transformations of peroxotungstate ions in sulphuric acid solutions are discussed on the basis of the results of potentiometric and conductimetric titration of solutions of rubidium peroxotungstates. The cationic peroxotungsten form, produced when Rb2WO6 reacts with concentrated sulphuric acid at pH<=1, was detected by the electromigration method. (author)

  17. Reactivity of the cadmium ion in concentrated phosphoric acid solutions.

    De Gyves, J; Gonzales, J; Louis, C; Bessiere, J

    1989-07-01

    The solvation transfer coefficients which characterize the changes of ion reactivity with phosphoric acid concentration have been calculated for cadmium from the constants of the successive chloride complexes, and for silver and diethyldithiophosphate from potentiometric measurements. They evidence the strong desolvation of the cadmium species in concentrated phosphoric acid media, causing a remarkable increase of its reactivity. They allow the results of liquid-liquid extraction, precipitation and flotation reactions to be correctly interpreted and their changes to be foreseen when the reagents are modified. PMID:18964794

  18. Shock Hugoniot and equations of states of water, castor oil, and aqueous solutions of sodium chloride, sucrose and gelatin

    Gojani, A. B.; Ohtani, K.; Takayama, K.; Hosseini, S. H. R.

    2016-01-01

    This paper reports a result of experiments for the determination of reliable shock Hugoniot curves of liquids, in particular, at relatively low pressure region, which are needed to perform precise numerical simulations of shock wave/tissue interaction prior to the development of shock wave related therapeutic devices. Underwater shock waves were generated by explosions of laser ignited 10 mg silver azide pellets, which were temporally and spatially well controlled. Measuring temporal variation of shock velocities and over-pressures in caster oil, aqueous solutions of sodium chloride, sucrose and gelatin with various concentrations, we succeeded to determine shock Hugoniot curves of these liquids and hence parameters describing Tait type equations of state.

  19. Chloride/formate exchange with formic acid recycling: a mechanism of active chloride transport across epithelial membranes

    The pathways for transport of Cl- and formate in microvillus membrane vesicles isolated from rabbit renal cortex were evaluated. An outward formate gradient stimulated the uptake of 36Cl-, and an outward 36Cl- gradient stimulated the uptake of formate, indicating Cl-/formate exchange. In addition, an inside alkaline pH gradient induced the accumulation of formate, consistent with nonionic diffusion of formic acid. Although an inward Na+ gradient also stimulated uphill formate accumulation, this effect was abolished when ionophores were used to prevent the generation of a transmembrane pH gradient. An inside alkaline pH gradient only minimally stimulated the uptake of 82Br-, used as tracer for Cl-, confirming the absence of appreciable Cl-/OH- exchange. However, the same pH gradient in the presence of a physiologic formate concentration (0.2 mM) markedly stimulated 82Br- influx. These data suggest that Cl-/formate exchange with recycling of formic acid by nonionic diffusion is a potential mechanism for active Cl- absorption across the luminal membrane in the proximal tubule and perhaps in other epithelia

  20. Electrochemical behavior of enamel-coated carbon steel in simulated concrete pore water solution with various chloride concentrations

    Highlights: ► All enamels significantly improve the corrosion performance of steel in Ca(OH)2 with chloride. ► Pitting corrosion of uncoated and ME-coated steel occurred at different chloride concentrations. ► Calcium silicate mixed in enamel increased the cohesive strength of ME coating. ► The increased pores in inner layer reduced the cohesive strength of DE coating. ► The electrochemical properties of enamel-coated steel are sensitive to thickness variation. -- Abstract: The electrochemical behavior of enamel coated carbon steel in simulated concrete pore water solution with various chloride concentrations was investigated by open circuit potential, linear polarization resistance, and electrochemical impedance spectroscopy tests. The phase composition, microstructure, and tensile strength of enamels were characterized by X-ray diffraction, scanning electron microscopy, and pull-off tests. Three types of coatings with pure, mixed, and double enamels were studied and compared for their corrosion behavior. Test results indicated that all three types of enamel coatings can reduce the corrosion current density of carbon steel in an alkaline environment with chloride; the pure and double coatings are superior to the mixed enamel coating. Cohesive failures were observed within the three coatings while their interface with the steel substrate remained intact. In comparison with the pure enamel, the mixed enamel was stronger with smaller open channels formed due to the addition of calcium silicate and the double enamel was weaker with larger air bubbles trapped in the inner pure enamel layer by the outer mixed enamel layer

  1. Removal of bromide by aluminium chloride coagulant in the presence of humic acid.

    Ge, Fei; Shu, Haimin; Dai, Youzhi

    2007-08-17

    Bromide can form disinfection by-products (DBPs) in drinking water disinfection process, which have adverse effects on human health. Using aluminium chloride as a model coagulant, removal of bromide by coagulation was investigated in the absence or presence of humic acid (HA) in synthetic water and then was conducted in raw water. Results demonstrated that in synthetic water, 93.3-99.2% removal efficiency of bromide was achieved in the absence of HA with 3-15 mg/L coagulant, while 78.4-98.4% removal efficiency of bromide was obtained in the presence of HA with the same coagulant dosage and 86.8-98.8% HA was removed simultaneously. Bromide in raw water was removed 87.0% with 15 mg/L coagulant. HA apparently reduced the removal of bromide with low coagulant dosage or at high pH, while minor influence on removal of bromide was observed with high coagulant dosage or at low pH. Thus, bromide could be reduced effectively by enhanced coagulation in drinking water treatment. PMID:17289257

  2. Enhanced coagulation of ferric chloride aided by tannic acid for phosphorus removal from wastewater.

    Zhou, Yunan; Xing, Xin-Hui; Liu, Zehua; Cui, Liwen; Yu, Anfeng; Feng, Quan; Yang, Haijun

    2008-05-01

    Phosphorus removal from wastewater is of great importance. In the present study, ferric chloride was selected as the coagulant, and tannic acid (TA), a natural polymer, as the coagulant aid to develop an effective coagulation process with the emphasis of phosphorus recovery from different types of wastewater. The results showed that TA can accelerate the settling speed by forming flocs with large size, reduce the residual Fe(III) to eliminate the yellow color caused by Fe(III), and slightly increase the phosphorus removal efficiency. The precipitate formed by TA-aided coagulation showed the advantage of releasing phosphorus faster than ferric phosphate, indicating the possibility of phosphorus recovery from wastewater as slow release fertilizer. To further understand the structural characteristics of the precipitate, analytical techniques such as Raman spectroscopy, X-ray photoelectron spectroscopy and matrix-assisted laser desorption ionization-time of flight mass spectrometry were employed. The analytical results indicated that TA-Fe-P complex was formed during the coagulation/flocculation processes. Solid phase in the precipitate consisted of TA-Fe-P complex, Fe-TA complex and/or ferric hydroxyphosphate. PMID:18395769

  3. Effect of Fluid Flow on Zinc Electrodeposits from Acid Chloride Electrolytes. M.S. Thesis

    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.

  4. Actinide and lanthanide extraction from nitric acid solutions by flotation

    Flotation of thorium, plutonium(IV), uranium(VI) and gadolinium from aqueous nitric acid solutions (HNO3) was investigated using lauryl phosphoric acid (LPA) as a SAS-collector. It is established that the extent of removal of the metal ions increases with the amount of LPA introduced, regardless of the solution acidity. It is shown that in principle ∼ 100% extraction of plutonium(IV) and thorium by flotation is possible regardless of the acidity of aqueous solutions. Ca(NO3)2 added to the system does not significantly affect the flotation extraction of thorium. (author) 14 refs.; 5 figs

  5. Solubilities of carbon dioxide in the eutectic mixture of levulinic acid (or furfuryl alcohol) and choline chloride

    Highlights: • Solubilities of carbon dioxide in six renewable deep eutectic solvents (DESs) have been reported. • The experimental data were well correlated by Henry’s law. • The dissolution Gibbs free energy, enthalpy, and entropy changes were derived. • The absorption capacities of CO2 in present DESs and other DESs as well as several ionic liquids were compared. - Abstract: The solubilities of carbon dioxide (CO2) in the renewable deep eutectic solvents (DESs) containing levulinic acid (or furfuryl alcohol) and choline chloride were determined at temperatures (303.15, 313.15, 323.15, and 333.15) K and pressures up to 600.0 kPa using an isochoric saturation method. The mole ratios of levulinic acid (or furfuryl alcohol) to choline chloride were fixed at 3:1, 4:1 and 5:1. Standard Gibbs free energy, dissolution enthalpy and dissolution entropy were calculated from Henry’s law constant of CO2 in the DESs. Results indicated that levulinic acid based DESs are more effective to capture CO2 than furfuryl alcohol based ones. The solubility of CO2 in the DESs increased with increasing mole ratio of levulinic acid (or furfuryl alcohol) to choline chloride as well as pressure and decreased with increasing temperature

  6. Effect of pore water velocities and solute input methods on chloride transport in the undisturbed soil columns of Loess Plateau

    Zhou, BeiBei; Wang, QuanJiu

    2016-04-01

    Studies on solute transport under different pore water velocity and solute input methods in undisturbed soil could play instructive roles for crop production. Based on the experiments in the laboratory, the effect of solute input methods with small pulse input and large pulse input, as well as four pore water velocities, on chloride transport in the undisturbed soil columns obtained from the Loess Plateau under controlled condition was studied. Chloride breakthrough curves (BTCs) were generated using the miscible displacement method under water-saturated, steady flow conditions. Using the 0.15 mol L-1 CaCl2 solution as a tracer, a small pulse (0.1 pore volumes) was first induced, and then, after all the solution was wash off, a large pulse (0.5 pore volumes) was conducted. The convection-dispersion equation (CDE) and the two-region model (T-R) were used to describe the BTCs, and their prediction accuracies and fitted parameters were compared as well. All the BTCs obtained for the different input methods and the four pore water velocities were all smooth. However, the shapes of the BTCs varied greatly; small pulse inputs resulted in more rapid attainment of peak values that appeared earlier with increases in pore water velocity, whereas large pulse inputs resulted in an opposite trend. Both models could fit the experimental data well, but the prediction accuracy of the T-R was better. The values of the dispersivity, λ, calculated from the dispersion coefficient obtained from the CDE were about one order of magnitude larger than those calculated from the dispersion coefficient given by the T-R, but the calculated Peclet number, Pe, was lower. The mobile-immobile partition coefficient, β, decreased, while the mass exchange coefficient increased with increases in pore water velocity.

  7. Corrosion behaviour of 316L stainless steel and anti-corrosion materials in a high acidified chloride solution

    Jin, Z.H. [Shanghai University of Electric Power, Shanghai Engineering Research Center of Energy-Saving in Heat Exchange Systems, Shanghai Key Laboratory of Colleges and Universities for Corrosion Control in Electric Power System and Applied Electrochemistry, 2103 Pingliang Road, Shanghai 200090 (China); Ge, H.H., E-mail: gehonghua@shiep.edu.cn [Shanghai University of Electric Power, Shanghai Engineering Research Center of Energy-Saving in Heat Exchange Systems, Shanghai Key Laboratory of Colleges and Universities for Corrosion Control in Electric Power System and Applied Electrochemistry, 2103 Pingliang Road, Shanghai 200090 (China); Lin, W.W. [Shanghai University of Electric Power, Shanghai Engineering Research Center of Energy-Saving in Heat Exchange Systems, Shanghai Key Laboratory of Colleges and Universities for Corrosion Control in Electric Power System and Applied Electrochemistry, 2103 Pingliang Road, Shanghai 200090 (China); Zong, Y.W.; Liu, S.J. [Power Plant of Baoshan Iron and Steel Co., Ltd, Tieli Road, Shanghai 200941 (China); Shi, J.M. [Technical University of Braunschweig (Germany)

    2014-12-15

    Highlights: • Severe general corrosion accompanied by localized pitting occurred on 316L SS surface in a high acidified chloride solution. • Surface roughness, surface potential difference and the electrochemical non-homogeneity of 316L SS in the test solution were investigated. • TA2, type 2507 SS and type 254SMo SS exhibit good corrosion resistance in the test solution. - Abstract: The corrosion behaviour of a type 316L (UNS S31603) stainless steel (SS) expansion joint in a simulated leaching solution of sediment on blast furnace gas pipeline in a power plant is investigated by using dynamic potential polarization curves, electrochemical impedance spectroscopy (EIS), optical microscope, atomic force microscope (AFM) and Scan Kelvin Probe (SKP). Severe general corrosion accompanied by pitting corrosion occurs on the type 316L SS surface in this solution. As the immersion period increases, the charge transfer resistance R{sub ct} decreases, the dissolution rate accelerates, the surface roughness increases and the surface potential difference enhances significantly. Then eight corrosion-resistant materials are tested, the corrosion rates of type 254SMo SS, type 2507 SS and TA2 are relatively minor in the solution. The corrosion resistance properties of TA2 is most excellent, indicating it would be the superior material choice for blast furnace gas pipeline.

  8. Corrosion behaviour of 316L stainless steel and anti-corrosion materials in a high acidified chloride solution

    Highlights: • Severe general corrosion accompanied by localized pitting occurred on 316L SS surface in a high acidified chloride solution. • Surface roughness, surface potential difference and the electrochemical non-homogeneity of 316L SS in the test solution were investigated. • TA2, type 2507 SS and type 254SMo SS exhibit good corrosion resistance in the test solution. - Abstract: The corrosion behaviour of a type 316L (UNS S31603) stainless steel (SS) expansion joint in a simulated leaching solution of sediment on blast furnace gas pipeline in a power plant is investigated by using dynamic potential polarization curves, electrochemical impedance spectroscopy (EIS), optical microscope, atomic force microscope (AFM) and Scan Kelvin Probe (SKP). Severe general corrosion accompanied by pitting corrosion occurs on the type 316L SS surface in this solution. As the immersion period increases, the charge transfer resistance Rct decreases, the dissolution rate accelerates, the surface roughness increases and the surface potential difference enhances significantly. Then eight corrosion-resistant materials are tested, the corrosion rates of type 254SMo SS, type 2507 SS and TA2 are relatively minor in the solution. The corrosion resistance properties of TA2 is most excellent, indicating it would be the superior material choice for blast furnace gas pipeline

  9. Anodic behaviour of the stainless steel AISI 430 in aqueous solutions of chloride and sulphate ions

    The kinetics of the dissolution of stainless steel AISI 430 in the presence of chloride and sulphate ions has been studied in terms of the ion concentration, the pH variation, and the velocity of the working electrode. The experimental method utilized was the potentiostatic anodic polarization, and the reactants used were NaCl and Na2 SO4 at room temperature. Atomic Absorption spectrophotometry and Auger Electrons spectroscopy (AES) analyses were made in order to support the interpretation of results obtained by means of the potentiostatic polarization method. (author)

  10. Standard practice for exposure of metals and alloys by alternate immersion in neutral 3.5% Sodium Chloride solution

    American Society for Testing and Materials. Philadelphia

    1999-01-01

    1.1 This practice covers procedures for making alternate immersion stress corrosion tests in 3.5 % sodium chloride (NaCl) (). It is primarily for tests of aluminum alloys (Test Method G 47) and ferrous alloys, but may be used for other metals exhibiting susceptibility to chloride ions. It sets forth the environmental conditions of the test and the means for controlling them. Note 1 Alternate immersion stress corrosion exposures are sometimes made in substitute ocean water (without heavy metals) prepared in accordance with Specification D 1141. The general requirements of this present practice are also applicable to such exposures except that the reagents used, the solution concentration, and the solution pH should be as specified in Specification D 1141. 1.2 This practice can be used for both stressed and unstressed corrosion specimens. Historically, it has been used for stress-corrosion cracking testing, but is often used for other forms of corrosion, such as uniform, pitting, intergranular, and galvanic. ...

  11. Effect of electrolytes on surface tension and surface adsorption of 1-hexyl-3-methylimidazolium chloride ionic liquid in aqueous solution

    Surface and bulk properties of 1-hexyl-3-methylimidazolium chloride [C6mim][Cl] as an ionic liquid (IL) have been investigated by surface tension and electrical conductivity techniques at various temperatures. Results reveal that the ionic liquid behaves as surfactant-like and aggregates in aqueous solution. Critical aggregation concentration (cac) values obtained by conductivity and surface tension measurements are in good agreement with values found in the literature. A series of important and useful adsorption parameters including cac, surface excess concentration (Γ), and minimum surface area per molecule (Amin) at the air + water interface were estimated from surface tension in the presence and absence of different electrolytes. Obtained data show that the surface tension as well as the cac of [C6mim][Cl] is reduced by electrolytes. Also, values of surface excess concentration (Γ) show that the IL ions in the presence of electrolyte have much larger affinity to adsorption at the surface and this affinity increased in aqueous electrolyte solution in the order of I- > Br- > Cl- for counter ion of salts that was explained in terms of a larger repulsion of chloride anions from interface to the bromide and iodide anion as well as difference in their excess polarizability.

  12. Comparative Study of Berberis vulgaris Fruit Extract and Berberine Chloride Effects on Acetic Acid-Induced Colitis in Rats

    Minaiyan, Mohsen; Ghannadi, Alireza; Mahzouni, Parvin; Jaffari-Shirazi, Elham

    2011-01-01

    Antioxidant and immunomodulatory effects of anthocyanins are abundant in berberry fruits suggesting that they may have beneficial effects on inflammatory bowel diseases (IBD). The present study was carried out to investigate the anti-colitic effect of Berberis vulgaris fruit extract (BFE) compared to berberine chloride (BEC) and corticosteroids using an animal model of acetic acid induced experimental colitis. BFE with three different doses (375, 750, and 1500 mg/Kg) was administered orally o...

  13. Visible-Light-Mediated Synthesis of Amides from Aldehydes and Amines via in Situ Acid Chloride Formation.

    Iqbal, Naeem; Cho, Eun Jin

    2016-03-01

    An efficient visible-light photocatalysis-based one-pot amide synthesis method was developed; visible-light irradiation of a mixture of an aldehyde, tert-butyl hydrogen peroxide, and N-chlorosuccinimide using a Ru(bpy)3Cl2 photocatalyst afforded an acid chloride, which subsequently reacted with amine to yield the corresponding amide. The reaction was used to synthesize moclobemide and a D3 receptor intermediate. PMID:26836367

  14. Studies on the separation of Ir(IV) and Ru(III) from chloride solutions using supported liquid membrane technique

    Due to limited resources, the gap between supply and demand of the platinum group metals (Rh, Ru, Ir, Pt, Pd) is increasing. Recycling after their use is an important resource in seeking to meet growing demand for these metals. Supported liquid membrane (SLM) technique is one of the promising techniques for the separation and recovery of species from their very dilute solutions where under similar conditions other conventional techniques are not economical. In the present work the transfer of ruthenium(III) from chloride solutions across supported liquid membrane and its separation from iridium(IV) was studied. Cyanex 923 (C923) and Alamine 336 (A336) as ion carriers were applied. Based on the results obtained in solvent extraction experiments it is expected that the presence of the Ru in the source phase will not affect on the transport of Ir(IV). Moreover, when both metals were present in the mixture the extraction of Ru decreased

  15. Polymer-clay nanocomposites obtained by solution polymerization of vinyl benzyl triammonium chloride in the presence of advanced functionalized clay

    Raluca Ianchis; Dan Donescu; Ludmila Otilia Cinteza; Violeta Purcar; Cristina Lavinia Nistor; Critian Petcu; Cristian Andi Nicolae; Raluca Gabor; Silviu Preda

    2014-05-01

    Polymer-clay nanocomposites were synthesized by solution polymerization method using advanced functionalized clay and vinyl benzyl trimethyl ammonium chloride as monomer. First stage consisted in the silylation of a commercial organo-modified clay-Cl 20A using alkoxysilanes with different chain lengths. In the second step, the synthesis and characterization of polymer-nanocomposites were followed. To evaluate the clay functionalization process as well as the final polymer-clay products, thermogravimetric,X-ray diffraction, dynamic light scattering, Fourier transform infrared spectroscopy and three test liquid contact angles analyses were used. The loss of ammonium ions from commercial clay, the grafting degree, the lengths and the nature of alkyl chain influence the dispersion of the advanced modified clay into the polymer solution and, furthermore, the properties of the final polymer-clay nanocomposite film.

  16. Removal of copper (II) from aqueous solutions by flotation using polyaluminum chloride silicate (PAX-XL60 S) as coagulant and carbonate ion as activator.

    Ghazy, S E; Mahmoud, I A; Ragab, A H

    2006-01-01

    Flotation is a separation technology for removing toxic heavy metal ions from aqueous solutions. Here a simple and rapid flotation procedure is presented for the removal of copper(II) from aqueous solutions. It is based on the use of polyaluminum chloride silicate (PAX-XL60 S) as coagulant and flocculent, carbonate ion as activator and oleic acid (HOL) as surfactant. Both ion and precipitate flotation are included depending on the solution pH. Ion and precipitate flotation in the aqueous HOL-PAX-XL60 S-Cu2+-CO3(2-) system gave powerful preferential removal of Cu2+ (F -100%) over the HOL-PAX-XL60 S-Cu2+ system containing no CO3(2+) ion (F approximately 86%). The role of CO3(2-) ion is also evident from decreasing the dose of PAX-XL60 S from 700 mg l(-1) to 200 mg l(-1). The other parameters, influencing the flotation process, namely: metal ion, surfactant and PAX-XL60 S concentrations, ionic strength, temperature and foreign ions were examined. Moreover, the procedure was successfully applied to recover Cu2+ ions from different volumes up to 11 and from natural water samples. PMID:16457175

  17. Thermodynamic study on redox reactions of boiling nitric acid solutions

    In order to understand corrosion of metals in nitric acid solutions, it is necessary to know the generation mechanism of high equilibrium potential in the solutions, especially under boiling conditions. Existing nitrogen oxides in nitric acid solutions were first analyzed by Raman spectroscopy and then existing amount of nitrogen oxides were examined by thermodynamic calculation using the SOLGASMIX software. The Raman spectroscopic analysis showed that the existing amount of un-dissociated HNO3 increased with increasing nitric acid concentration and solution temperature. The existing amount of NO2 also increased by thermal decomposition. The thermodynamic calculation showed that the important nitrogen oxides in nitric acid solutions are HNO3, NO3-, HNO2, NO2, and NO. The equilibrium potential of nitric acid solution is, however, mainly decided by the HNO3/HNO2 equilibrium. The thermodynamic calculation also suggested that the increased oxidization potential on the heat-transfer surface is attributed to the reduction of nitrous acid concentration by the thermal decomposition of nitrous acid on the surface and the continuous removal of decomposition product from the solutions by boiling babbles. (author)

  18. Aggregation and adsorption behavior of cetylpyridinium chloride in aqueous sodium salicylate and sodium benzoate solutions.

    Mukhim, T; Dey, J; Das, S; Ismail, K

    2010-10-15

    The critical micelle concentration (cmc) values of cetylpyridinium chloride (CPC) were determined in the presence of salicylate and benzoate ions in the less explored concentration region where viscosity is Newtonian. The cmc of CPC decreased from 9 x 10(-4) to 7 x 10(-7) and 3 x 10(-6) mol kg(-1) by adding about 0.3 mol kg(-1) of salicylate and benzoate, respectively. The ortho hydroxyl group in salicylate thus has a remarkable influence on the micellization of CPC and the extent of this favorable effect is found to be about 3.5 kJ mol(-1). The Corrin-Harkins equation was modified to explain the variation of cmc with electrolyte concentration in the presence of mixed counterions. The slope of the equation does not provide the value of the total counterion binding constant (beta), but gives us information about the lower limit to the value of beta, which is found to be 0.66. Addition of salicylate and benzoate increases the counterion binding to CPC micelles compared to that in the presence of chloride alone. An adsorption isotherm was derived to estimate the surface excess of CPC in the presence of mixed counterions. PMID:20673910

  19. Diluent effect on the extraction of uranium(VI) from hydrochloric acid solutions by trioctylamine

    The extraction of uranium(VI) and divalent metals (copper, zinc and cadmium) from hydrochloric acid solutions by trioctylamine (TOA) has been examined using various toluene, m-xylene, nitrobenzene, carbon tetrachloride, chloroform and 1,2-dichloroethane. It is found that a parabolic dependence of the distribution coefficient on the solubility parameter of diluent is not observed in these extraction systems. The results obtained are investigated in comparison with the extraction of uranium(VI) and divalent metals by trioctylmethylammonium chloride (TOMAC) in organic solvents in which the distribution coefficient and the enthalpy change associated with the metal extraction can be expressed in terms of the solubility parameter of extractant, diluent and the complex formed in the organic phase and their molar volume by assuming a regular solution. Consequently, since the solutions of TOA x HCl in organic solvents are not regarded as regular solutions, it is expected that the extraction of uranium(VI) from hydrochloric acid solutions by TOA is not always explained in the view point of a regular solution therapy. 16 references, 7 figures, 9 tables

  20. Pyrrhotite oxidation in weakly acidic solutions

    Complete text of publication follows: The kinetics and mechanism of pyrrhotite (for simplicity noted FeS) oxidation by dissolved oxygen was investigated in weakly acidic solutions as a function of pH (2.75 to 3.45) and temperature (25 to 45 C). The changes in Eh, pH and total dissolved iron were monitored to quantify the reaction progress. Additionally, Fourier transform infrared spectroscopy (FTIR) was used to characterize the oxidation products of FeS. The experimental results demonstrate the importance of temperature and initial pH for the FeS oxidative dissolution. The amounts of dissolved iron (nFe) and removed H+ (nH) increase with temperature and initial [H+]. The activation energy of FeS oxidative dissolution is 41.6 ± 10.7 kJ mol-1 at initial pH=3.00 suggesting that the kinetic regime is controlled by a mix of diffusion and surface reaction (De Guidici et al., 2005). It was found that the reaction order of oxidative dissolution of FeS is 1.0 ± 0.02 (25 C) with respect to initial [H+]. FTIR spectroscopy indicated the presence of several sulfur species (S0, Sn2-, S2O32-, SO32- and SO42-) and ferric hydroxides or oxyhydroxide (Fe(OH)3 and goethite) on residual FeS surface. It is important to note that the experimental ratios of nH over nFe (nH:nFe) observed at 25 C decrease over a first period of time (0-4 h) of FeS oxidative dissolution from 7.97 down to 2.01. Afterwards, the nH:nFe ratio becomes lower than 2 and remains roughly constant (4-72 h). At higher temperatures (35 and 45 C) and pH 3.00, nH:nFe≤2 and is quasi-invariant over the reaction time. The experimental observations suggest a mechanism based on the protonation of FeS surface (Chirita and Descostes, 2006) followed by oxidation of FeS by dissolved oxygen to produce Fe2+, S0 and Sn2-. Fe2+ is unstable in oxidative conditions (Descostes et al., 2002) and transforms into Fe(OH)3(s) and goethite after approximately 30 h of reaction. References:1) De Guidici G., Rossi A., Fanfani L., Lattanzi P

  1. Pyrrhotite oxidation in weakly acidic solutions

    Chirita, P. [Univ Cariova, Craiova 200440 (Romania); Descostes, M. [CEA/DEN/DANS/DPC/SECR Lab Radionuclides Migrat Measurements and Modelling, F-91191 Gif Sur Yvette (France); Schlegel, M.L. [CEA/DEN/DANS/DPC/SCP Lab Reactiv Surfaces and Interfaces, F-91191 Gif Sur Yvette (France)

    2007-08-15

    Complete text of publication follows: The kinetics and mechanism of pyrrhotite (for simplicity noted FeS) oxidation by dissolved oxygen was investigated in weakly acidic solutions as a function of pH (2.75 to 3.45) and temperature (25 to 45 C). The changes in Eh, pH and total dissolved iron were monitored to quantify the reaction progress. Additionally, Fourier transform infrared spectroscopy (FTIR) was used to characterize the oxidation products of FeS. The experimental results demonstrate the importance of temperature and initial pH for the FeS oxidative dissolution. The amounts of dissolved iron (n{sub Fe}) and removed H{sup +} (n{sub H}) increase with temperature and initial [H{sup +}]. The activation energy of FeS oxidative dissolution is 41.6 {+-} 10.7 kJ mol{sup -1} at initial pH=3.00 suggesting that the kinetic regime is controlled by a mix of diffusion and surface reaction (De Guidici et al., 2005). It was found that the reaction order of oxidative dissolution of FeS is 1.0 {+-} 0.02 (25 C) with respect to initial [H{sup +}]. FTIR spectroscopy indicated the presence of several sulfur species (S{sup 0}, S{sub n}{sup 2-}, S{sub 2}O{sub 3}{sup 2-}, SO{sub 3}{sup 2-} and SO{sub 4}{sup 2-}) and ferric hydroxides or oxyhydroxide (Fe(OH){sub 3} and goethite) on residual FeS surface. It is important to note that the experimental ratios of n{sub H} over n{sub Fe} (n{sub H}:n{sub Fe}) observed at 25 C decrease over a first period of time (0-4 h) of FeS oxidative dissolution from 7.97 down to 2.01. Afterwards, the n{sub H}:n{sub Fe} ratio becomes lower than 2 and remains roughly constant (4-72 h). At higher temperatures (35 and 45 C) and pH 3.00, n{sub H}:n{sub Fe}{<=}2 and is quasi-invariant over the reaction time. The experimental observations suggest a mechanism based on the protonation of FeS surface (Chirita and Descostes, 2006) followed by oxidation of FeS by dissolved oxygen to produce Fe{sup 2+}, S{sup 0} and S{sub n}{sup 2-}. Fe{sup 2+} is unstable in

  2. Flotation extraction of rhodanide indium complexes from acidic solutions

    Principle possibility of flotation extraction of indium rhodanide complexes from acid solutions (H2SO4, HCl, HBr, HF, HNO3, HI, H3PO4, CH3COOH, HClO4) is shown. Optimum conditions for their extraction are created in the range of moderate (0.01-0.1 g-eq./l acid in solution) acidity when using quaternary compounds, containing from 13 to 18 carbon atoms in the alkyl part as collectors. It is established experimentally that indium is extracted from weakly acidic solutions in the form of mixed complex anions according to ion exchange mechanism, from strong acidic ones - mainly in the form of acid complexes similar to addition reactions

  3. Effects of Chloride Ion on the Texture of Copper and Cu-ZrB2 Coatings Electrodeposited from Copper Nitrate Solution in Different Plating Modes

    Dongming GUO; Min ZHANG; Zhuji JIN; Renke KANG

    2006-01-01

    For the first time, the texture of copper and Cu-ZrB2 coatings produced from copper nitrate solution was studied. Chloride ion shows different effects on the deposit texture under direct current(DC)and pulse ion concentration exceeds 20 mg/I. The addition of ZrB2 particles enhances the cathodic polarization of copper deposition, which improves the growth of(111)plane. However, this improvement can be eliminated by further addition of chloride ion.

  4. A Fiber-Optic Sensor Using an Aqueous Solution of Sodium Chloride to Measure Temperature and Water Level Simultaneously

    Wook Jae Yoo

    2014-10-01

    Full Text Available A fiber-optic sensor system using a multiplexed array of sensing probes based on an aqueous solution of sodium chloride (NaCl solution and an optical time-domain reflectometer (OTDR for simultaneous measurement of temperature and water level is proposed. By changing the temperature, the refractive index of the NaCl solution is varied and Fresnel reflection arising at the interface between the distal end of optical fiber and the NaCl solution is then also changed. We measured the modified optical power of the light reflected from the sensing probe using a portable OTDR device and also obtained the relationship between the temperature of water and the optical power. In this study, the water level was simply determined by measuring the signal difference of the optical power due to the temperature difference of individual sensing probes placed inside and outside of the water. In conclusion, we demonstrate that the temperature and water level can be obtained simultaneously by measuring optical powers of light reflected from sensing probes based on the NaCl solution. It is anticipated that the proposed fiber-optic sensor system makes it possible to remotely monitor the real-time change of temperature and water level of the spent fuel pool during a loss of power accident.

  5. Release of cetyl pyridinium chloride from fatty acid chelate temporary dental cement

    Hurt, Andrew; Coleman, Nichola J.; Tüzüner, Tamer; Bagis, Bora; Korkmaz, Fatih Mehmet; Nicholson, John W.

    2016-01-01

    Abstract Objective To determine whether the antimicrobial nature of a fatty acid chelate temporary dental cement can be enhanced by the addition of 5% cetyl pyridinium chloride (CPC). Materials and methods The temporary cement, Cavex Temporary was employed, and additions of CPC were made to either the base or the catalyst paste prior to mixing the cement. Release of CPC from set cement specimens was followed using reverse-phase HPLC for a period of up to 2 weeks following specimen preparation. Potential interactions between Cavex and CPC were examined by Fourier transform infrared spectroscopy (FTIR) and antimicrobial effects were determined using zone of inhibition measurements after 24 h with disc-shaped specimens in cultured Streptococcus mutans. Results FTIR showed no interaction between CPC and the components of the cement. CPC release was found to follow a diffusion mechanism for the first 6 h or so, and to equilibrate after approximately 2 weeks, with no significant differences between release profiles when the additive was incorporated into the base or the catalyst paste. Diffusion was rapid, and had a diffusion coefficient of approximately 1 × 10−9 m2 s−1 in both cases. Total release was in the range 10–12% of the CPC loading. Zones of inhibition around discs containing CPC were significantly larger than those around the control discs of CPC-free cement. Conclusions The antimicrobial character of this temporary cement can be enhanced by the addition of CPC. Such enhancement is of potential clinical value, though further in vivo work is needed to confirm this. PMID:27335898

  6. Development of a stable solution of 5-aminolaevulinic acid for intracutaneous injection in photodynamic therapy.

    de Blois, A W; Grouls, R J E; Ackerman, E W; Wijdeven, W J A

    2002-01-01

    Photodynamic therapy using 5-aminolaevulinic acid (ALA) as a photosensitiser is a new treatment modality for basal cell carcinomas. Until now ALA has been used topically as a cream. As this administration route leads sometimes to insufficient penetration in the skin, an intracutaneously injectable solution of ALA was developed. The influence of pH, concentration and temperature on the degradation of ALA in aqueous solution was investigated in order to optimise the formulation of the injection. In 0.1% ALA solutions with pH values between 4 and 8 a pH dependency of ALA degradation was shown, comprising fast decomposition at pH values higher than 7, whereas at a pH value of 6 or lower the solutions remained within the range of 90-110% of the initial concentration for at least 128 days. An increase of degradation rate with increasing concentrations became evident which is consistent with the supposed second-order degradation kinetics. After accelerated stability research at 63 degrees C and 85 degrees C a shelf life of 281 days for a 0.1% ALA solution pH 5 was calculated from an Arrhenius plot. A 2% ALA solution was proven to be isotonic. From our results a 0.1-2% ALA solution with pH 5 and an appropriate amount of sodium chloride to obtain isotonicity is recommended as an injectable solution. PMID:12181635

  7. POLYMER-SUPPORTED LEWIS ACID CATALYSTS. VI. POLYSTYRENE-BONDED STANNIC CHLORIDE CATALYST

    RAN Ruicheng; FU Diankui

    1991-01-01

    A polystyrene-bonded stannic chloride catalyst was synthesized by the method of lithium polystyryl combined with stannic chloride. This catalyst is a polymeric organometallic compound containing 0.25 mmol Sn(IV)/g catalyst. The catalyst showed sufficient stability and catalytic activity in organic reaction such as esterification, acetalation and ketal formation, and it could be reused many times without losing its catalytic activity.

  8. Thermophysical properties of sodium nitrate and sodium chloride solutions and their effects on fluid flow in unsaturated media

    Understanding movement of saline sodium nitrate (NaNO3) waste solutions is important for assessing the contaminant migration near leaking waste storage tanks in the unsaturated zone at the Hanford site (Washington, USA). The purpose of this study is to contribute a basic understanding of effects of the thermophysical behavior of NaNO3 solutions on fluid flow in unsaturated media. We first present mathematical expressions for the dependence of density, viscosity, solubility and vapor pressure of NaNO3 solutions on both salt concentration and temperature, which were determined by fitting from published measured data. Because the previous studies of thermophysical behavior of sodium chloride (NaCl) solutions can provide a basis for those of NaNO3 solutions, we also present a comparison of thermophysical properties of both salt solutions. We have implemented the functional thermophysical properties of NaNO3 solutions into a new TOUGH2 equation-of-state module EWASG-NaNO3, which is modified from a previous TOUGH2 equation-of-state module EWASG for NaCl. Using the simulation tool, we have investigated effects of the thermophysical properties on fluid flow in unsaturated media. The effect of density and viscosity of saline solutions has been long recognized. Here we focus our attention on the effect of vapor pressure lowering due to salinity. We present simulations of a one-dimensional problem to study this salinity-driven fluid flow. A number of simulations were performed using different values of thermal conductivity, permeability, and temperature, to illustrate conditions and parameters controlling these processes. Results indicate that heat conduction plays a very important role in this salinity-driven vapor diffusion by maintaining a nearly constant temperature. The smaller the permeability, the more water is transferred into the saline environment. Effects of permeability on water flow are also complicated by effects of capillary pressure and tortuosity. The higher

  9. Ionisation constants of inorganic acids and bases in aqueous solution

    Perrin, D D

    2013-01-01

    Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution, Second Edition provides a compilation of tables that summarize relevant data recorded in the literature up to the end of 1980 for the ionization constants of inorganic acids and bases in aqueous solution. This book includes references to acidity functions for strong acids and bases, as well as details about the formation of polynuclear species. This text then explains the details of each column of the tables, wherein column 1 gives the name of the substance and the negative logarithm of the ionization constant and column 2

  10. Material Solutions to Mitigate the Alkali Chloride-Induced High Temperature Corrosion

    Kiamehr, Saeed

    High temperature corrosion induced by potassium chloride (KCl) is a major challenge for biomass-based power plants. The current study aims at identification or development of alloys or coatings that can yield a better performance at a target metal temperature of 600oC compared to austenitic...... of metals. This was aimed at identifying the constituent elements of a corrosion resistant alloy. Calculations suggested Al, Si, Cr, Ti, Y, Ce, Ta, Hf and Zr as suitable oxide-forming elements as well as Mo, Ni and Co as suitable matrix-forming elements. However, the presence of potassium in the...... available alloys and obtain further knowledge on the mechanism of high temperature corrosion induced by KCl, a wide range of commercial and model alloys were exposed under conditions relevant to high temperature corrosion in biomass-firing power plants. The exposures were conducted at 600oC for 168h in...

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

    Crawford, C.L. [Westinghouse Savannah River Company, AIKEN, SC (United States); 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.

  12. Electrochemical oxidation of acid black 210 dye on the boron-doped diamond electrode in the presence of phosphate ions: Effect of current density, pH, and chloride ions

    The electrochemical oxidation of acid black 210 dye (AB-210) on the boron-doped diamond (BDD) was investigated under different pH conditions. The best performance for the AB-210 oxidation occurred in alkaline phosphate solution. This is probably due to oxidizing agents such as phosphate radicals and peroxodiphosphate ions, which can be electrochemically produced with good yields on the BDD anode, mainly in alkaline solution. Under this condition, the COD (chemical oxygen demand) removal was higher than that obtained from the model proposed by Comninellis. Electrolyses performed in phosphate buffer and in the presence of chloride ions resulted in faster COD and color removals in acid and neutral solutions, but in alkaline phosphate solution, a better performance in terms of TOC removal was obtained in the absence of chloride. Moreover, organochloride compounds were detected in all electrolyses performed in the presence of chloride. The AB-210 electrooxidation on BDD using phosphate as supporting electrolyte proved to be interesting since oxidizing species generated from phosphate ions were able to completely degrade the dye without producing organochloride compounds.

  13. Removal of plutonium from nitric acid-oxalic acid solutions using anion exchange method

    An anion exchange method using Amberlyst A-26 (MP) resin was developed for removal of Pu from nitric acid-oxalic acid solutions without destroying oxalate. The method consists of sorption of Pu(IV) on Amberlyst A-26, a macroporous anion exchange resin, from nitric acid-oxalic acid medium in the presence of Al(NO3)3. Pu(IV) breakthrough capacity of Amberlyst A-26 using synthetic feed solution was determined. (author)

  14. Acetic acid and lithium chloride effects on hydrothermal carbonization of lignocellulosic biomass.

    Lynam, Joan G; Coronella, Charles J; Yan, Wei; Reza, Mohammad T; Vasquez, Victor R

    2011-05-01

    As a renewable non-food resource, lignocellulosic biomass has great potential as an energy source or feedstock for further conversion. However, challenges exist with supply logistics of this geographically scattered and perishable resource. Hydrothermal carbonization treats any kind of biomass in 200 to 260°C compressed water under an inert atmosphere to produce a hydrophobic solid of reduced mass and increased fuel value. A maximum in higher heating value (HHV) was found when 0.4 g of acetic acid was added per g of biomass. If 1g of LiCl and 0.4 g of acetic acid were added per g of biomass to the initial reaction solution, a 30% increase in HHV was found compared to the pretreatment with no additives, along with greater mass reduction. LiCl addition also reduces reaction pressure. Addition of acetic acid and/or LiCl to hydrothermal carbonization each contribute to increased HHV and reduced mass yield of the solid product. PMID:21411315

  15. Anion exchange equilibrium of uranium and several other elements in mineral acid solutions containing tetrafluoroboric acid

    Volume distribution coefficients (Dv) were determined for the adsorption of U and several other elements on anion-exchange resin from mixed solutions of tetrafluoroboric acid and nitric acid or hydrochloric acid, and the effect of tetrafluoroboric acid on the adsorption of each element was studied. The addition of tetrafluoroboric acid, in general, slightly decreased the Dv values while Zr weakly adsorbed in the HBF4-HCl and HBF4-HNO3 solutions and Nb in the NBF4-HNO3 solutions. (author) 18 refs.; 4 figs

  16. Study of free acidity determinations in aqueous solution

    The object of this work is the study of the principal methods which can be applied to the measurement of 'free' acidity. In the first part, we define the various types of acidity which can exist in aqueous solution; then, after having studied some hydrolysis reactions, we compare the value of the neutralisation pH of the hydrated cation and that of the precipitation of the hydroxide. In the second part we have started to study the determination of the acidity of an aqueous solution. After having rapidly considered the 'total' acidity determination, we deal with the problem of the 'free' acidity titration. We have considered in particular certain methods: extrapolation of the equivalent point, colorimetric titrations with or without a complexing agent, and finally the use of ion-exchange resins with mixed aqueous and solvent solutions. (author)

  17. Corrosion protection of aluminium pretreated by vinyltriethoxysilane in sodium chloride solution

    The corrosion protection of vinyltriethoxysilane (VTES) films on aluminium during exposure to 3% NaCl was investigated using electrochemical impedance spectroscopy (EIS), potential-time measurements and optical microscopy coupled with image analysis. Composition and thickness of films were analyzed using Auger electron spectroscopy (AES) combined with depth profiling. It was shown that films deposited from 5% solution were significantly thicker and exhibited lower porosity and better corrosion stability, as compared to films deposited from 2 vol.% solution. VTES films deposited from 5 vol.% solutions and cured for 30 min exhibited better protection properties than other investigated films.

  18. Corrosion behaviour of Fe-Mn-Si-Al austenitic steel in chloride solution

    W. Krukiewicz; A. Grajcar; M. Opiela

    2009-01-01

    Purpose: The aim of the paper is to investigate the corrosion behaviour of the new-developed high-manganese austenitic steel in 0.5n NaCl solution.Design/methodology/approach: The steel used for the investigation was thermomechanically rolled and solution heat-treated from a temperature of 850°C. Corrosion resistance of investigated steel was examined using weight and potentiodynamic methods. In the weight method, the specimens were immersed in the prepared solution for 24h. In the potentiody...

  19. Attenuation coefficients of 123 keV γ-radiation by dilute solutions of sodium chloride

    The linear attenuation and mass attenuation (or absorption) coefficients of the 123 keV γ radiation from 57Co by dilute solutions of NaCl were studied for varying concentrations. The mixture rule for the theoretical calculation of attenuation coefficients was developed for solutions. This study explores the validity of the expected exponential attenuation absorption law for γ-radiation in solutions and also provides an alternative method for the direct determination of linear and mass attenuation coefficients of soluble salts in solid form without obtaining them in pure crystalline form. (Author)

  20. Thermal Stability of Acetohydroxamic Acid/Nitric Acid Solutions

    The transmutation of transuranic actinides and long-lived fission products in spent commercial nuclear reactor fuel has been proposed as one element of the Advanced Accelerator Applications Program. Preparation of targets for irradiation in an accelerator-driven subcritical reactor would involve dissolution of the fuel and separation of uranium, technetium, and iodine from the transuranic actinides and other fission products. The UREX solvent extraction process is being developed to reject and isolate the transuranic actinides in the acid waste stream by scrubbing with acetohydroxamic acid (AHA). To ensure that a runaway reaction will not occur between nitric acid and AHA, an analogue of hydroxyl amine, thermal stability tests were performed to identify if any processing conditions could lead to a runaway reaction

  1. Polymerization of beta-amino acids in aqueous solution

    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.

  2. Thermotropic liquid crystalline polyesters derived from bis-(4-hydroxybenzoyloxy)-2-methyl-1,4-benzene and aliphatic dicarboxylic acid chlorides

    Khudbudin Mulani; Mohasin Momin; Nitin Ganjave; Nayaku Chavan

    2015-09-01

    A series of thermotropic liquid crystalline polyesters derived from bis-(4-hydroxybenzoyloxy)-2-methyl-1,4-benzene (BHBOMB) and aliphatic dicarboxylic acid chlorides were investigated. All these polyesters were synthesized by interfacial polycondensation method and characterized by differential scanning calorimetry and wide-angle X-ray diffractometer. These polyesters consist of BHBOMB as a mesogenic diol and aliphatic diacid chlorides were used as flexible spacers. The length of oligomethylene units in polymer was varied from the trimethylene to the dodecamethylene groups. The transition temperatures and thermodynamic properties were studied for all these polymers. All these polyesters were soluble in chlorinated solvents such as chloroform, dichloromethane, dichloroethane, etc. More importantly, all these polyesters exhibited very large mesophase stability.

  3. Corrosion behavior of aluminum alloy 2024-T3 by 8-hydroxy-quinoline and its derivative in 3.5% chloride solution

    LI Song-mei; ZHANG Hong-rui; LIU Jian-hua

    2007-01-01

    The corrosion behavior of aluminum alloy 2024-T3 was studied in 3.5% NaCl solution with two fluorescence quinoline compounds named 8-hydroxy-quinoline(8HQ) and 8-hydroxy-quinoline-5-sulfonic acid(HQS). The open circuit potential(OCP) test result indicates that both compounds change the alloy corrosion potential by adsorbing on the electrode surface. Polarization measurements show that 8HQ is a mixed type inhibitor by blocking the active sites of the metal surface, while HQS is a corrosion accelerator by activating the cathodic reaction. Changes of the impedance parameters in the electrochemical impedance spectroscopy(EIS) are related to the adsorption of 8HQ on the metal surface, which leads to the formation of a protective layer. The impedance diagram in the solution with HQS is similar to the one without additional organic compounds. The morphology and composition of the protective layer were studied by using SEM/EDS. The result confirms the function of the additions that the effect of 8HQ is due to the insoluble aluminum chelate, Al(HQ)3, to prevent adsorption of chloride ion, while the effect of HQS is to break down the oxide film.

  4. Effect of heat treatment on pitting corrosion of austenitic Cr-Ni-Mo steels in sodium chloride solution

    The pitting corrosion resistance of Cr17Ni12Mo2,5 type steel under potentiostatic polarization in a sodium chloride solution is adversely affected by previous annealing. The data obtained were systematically dependent on annealing temperature, time and surface roughness. The corrosion current, the number of pits or the mean area of pit opening and the corrosion rate within the pits were increased by previous annealing at 550 to 7500C for 1-100 hrs. The highest corrosion rate estimated corresponded to heat treatments provoking severe sensitization to intergranular corrosion. The paercentage area of corrosion pit openings and the estimated pit penetration rates were several times higher for as-machined than for polished surfaces. It can be assumed that pitting corrosion is little affected by the carbon content and that molybdenum depletion of grain-boundary zones is responsible for the reduced pitting resistance of annealed steels. (orig./HP)

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

    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

  6. Precipitation of plutonium from acidic solutions using magnesium oxide

    Magnesium oxide will be used as a neutralizing agent for acidic plutonium-containing solutions. It is expected that as the magnesium oxide dissolves, the pH of the solution will rise, and plutonium will precipitate. The resulting solid will be tested for suitability to storage. The liquid is expected to contain plutonium levels that meet disposal limit requirements

  7. Radiolysis studies of uranyl nitrate solution in nitric acid medium

    The radiolysis of acidic uranyl nitrate solutions was investigated using Co-60 gamma radiation. Hydrogen peroxide was determined as a function of increasing dose. The UV-vis absorption spectra of the irradiated solutions were measured and the spectral changes were analyzed. The increasing dose increases the absorbance intensities, possibly by an increment in nitrate concentration produced by radiolysis, which can originate the formation of different uranyl complexes in solution. (author)

  8. X-ray fluorescence determination of Au, Pd and Pt from chloride solutions after preconcentration on cellulose filters

    The aim of this work was synthesis of new sorption cellulose filters for dynamic preconcentration of Au, Pd and Pt from chloride solutions and subsequent XRF determination of these elements on the filters. New filters were prepared by impregnation of a filter paper with solution of tri-n-octylamine and paraffin in hexane (TOA-filters). The effect of paraffin and TOA concentration in hexane on a content of nitrogen in a filter was studied. It was found that Au(III), Pd(II) and Pt(IV) were quantitatively recovered on the TOA-filters (filtering surface diameter of 23 mm, thickness of 0.15 mm) from 0.5 - 1 M HCl at a flow rates of 2-5 ml min-1 from 10-100 ml of solution. The mathematical model of sorption dynamics was offered for the estimation of potential possibilities of new impregnated sorbents and for the evaluation of optimum dynamic conditions allowing to achieve of maximum concentration efficiency (CEmax). The elements were determined directly on the filters by XRF spectrometer. Palladium was also determined on the TOA-filters after formation of coloured compounds of metal with 4-(2-pyridylazo)resorcinol (PAR) by diffuse reflectance spectroscopy with the calculation of calorimetric characteristics and using test-scale. (authors)

  9. Reduction of plutonium in acidic solutions by mesoporous carbons

    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. (author)

  10. Effect of nitrogen on the corrosion behavior of austenitic stainless steel in chloride solutions

    The effect of partial replacement of nickel with nitrogen on the mechanism of localized corrosion resistance and re-passivation for nitrogen-bearing stainless steel was investigated using anodic potentiodynamic polarization technique. The solutions used for this study contained 0.0, 0.05 and 0.33 M Fe3+ for solutions I, II and III respectively, in a total Cl- ion concentration 1 M. The pitting attack was found to be retarded by nitrogen addition and the samples were able to passivate as the nitrogen increase. Addition of nitrogen allows decreasing the percentage of Ni, but to a certain limit. Nitrogen is adsorbed on the interface of the metal oxide and results in repulsion of Cl- ions. Moreover, it reacts with H+ ions in the solution leading to higher pH, which explains the retardation effect of nitrogen to corrosion. (author)

  11. Uranium sorption from nitric acid solutions by cationites and polyampholytes

    Sorption of uranium ions with KU-2 x 8 sulfonic cation exchanger, KFP-12 phosphoric acid cation exchanger and aminophosphoric acid ampholytes was examined in nitric acid solutions containing different amounts of HNO3. Formation of polymeric complexes was confirmed by IR spectra. The ion-coordination mechanism of U sorption with KFP-12 cation exchanger was clearly manifested; sorption of U as a single-charged nitrate complex ion is also possible. The isotherms of sorption of the U ions with KFP-12 cation exchanger have a convex shape with a sharply ascending portion at low U concentrations, which is favorable for U recovery from raffinate solutions. Nitrogen-phosphorus-containing polyampholytes also possess a high sorption power with respect to the U ions in nitric acid solutions. The highest exchange capacity is exhibited by polyacrylate base ANKF-80 and ANKF-86 polyampholytes

  12. The role of temperature in copper electrocrystallization in ammonia-chloride solutions

    This paper presents the analysis of temperature effect on the copper electrocrystallization process from the stainless steel/Cu(II)-Cu(I)-NH4Cl-NH3-H2O system. Electrochemical techniques and scanning electron microscopy with energy dispersion spectroscopy were employed. An increment in temperature had a favorable effect in increasing the kinetic and nucleation parameters, favoring the copper reduction on the stainless steel substrate. From the chronoamperometric study, it was possible to find the transfer coefficient (α), which does not have a significant variation with temperature, and the exchange current density (i ) for different temperatures, where a 50.63 kJ/mol value was estimated for the activation energy. The potentiostatic study suggested the presence of two processes involved: an electron transfer reaction and a 3D nucleation-growth process, under combined charge transfer and diffusion limitations. In addition, an important current contribution could be accounted for on the basis of the existence of a capacitive component in the system. This capacitive behavior was associated to the oxide layer (Cr2O3)-chloride interactions on the stainless steel surface. Current transients analyses at different potentials, based on the models of: Milchev (low overpotential), Scharifker-Mostany (SM) and Heermann-Tarallo (HT) (high overpotential) allowed to obtain the values of nucleation parameters, such as: the nucleation rate constant (A), the active nucleation sites number (N ), the stationary nucleation rate (I st = A x N ) and the nuclei saturation number (N s). Finally, the deposits obtained were analyzed by SEM, showing an acceptable correlation between the nucleation parameters and morphology of the deposits obtained. An increment in temperature favored the growth of the cluster before the coalescence occurred

  13. Response surface optimization of acid red 119 dye from simulated wastewater using Al based waterworks sludge and polyaluminium chloride as coagulant.

    Moghaddam, S Sadri; Moghaddam, M R Alavi; Arami, M

    2011-04-01

    In this research, the performance of Polyaluminium Chloride (PAC) and Polyaluminium Chloride sludge (PACS) as coagulants for acid red 119 (AR119) dye removal from aqueous solutions were compared. The sample of PACS was collected from "Baba Sheikh Ali" water treatment plant (Isfahan, Iran) where PAC is used as a coagulant in the coagulation/flocculation process. A response surface methodology was applied to evaluate the simple and combined effects of the operating variables including initial pH, coagulant dosage and initial dye concentration and to optimize the operating conditions of the treatment process. Results reveal that the optimal conditions for dye removal were initial pH 3.42, coagulant dosage of 4.55 g dried PACS/L and initial dye concentration of 140 mg/L for PACS, while the optimal initial pH, coagulant dosage and initial dye concentration for PAC were 3.8, 57 mg/L and 140 mg/L, respectively. Under these optimal values of process parameters, the dye removal efficiency of 94.1% and 95.25% was observed for PACS and PAC, respectively. Although lower amount of PAC in comparison with PACS was needed for specific dye removal, the reuse of PACS as a low-cost material can offer some advantages such as high efficiency for AR119 dye removal and economic savings on overall water and wastewater treatment plant operation costs. PMID:21216522

  14. Evaluation of the cytotoxic effects of ophthalmic solutions containing benzalkonium chloride on corneal epithelium using an organotypic 3-D model

    Jessen Bart A

    2009-07-01

    Full Text Available Abstract Background Benzalkonium chloride (BAC is a common preservative used in ophthalmic solutions. The aim of this study was to compare the cytotoxic effects of BAC-containing ophthalmic solutions with a BAC-free ophthalmic solution using an organotypic 3-dimensional (3-D corneal epithelial model and to determine the effects of latanoprost ophthalmic solution and its BAC-containing vehicle on corneal thickness in a monkey model. Methods The cytotoxicity of commercially available BAC-containing ophthalmic formulations of latanoprost (0.02% BAC and olopatadine (0.01% BAC was compared to that of BAC-free travoprost and saline in a corneal organotypic 3-D model using incubation times of 10 and 25 minutes. To compare the extent of differentiation of 3-D corneal cultures to monolayer transformed human corneal epithelial (HCE-T cell cultures, expression levels (mRNA and protein of the corneal markers epidermal growth factor receptor, transglutaminase 1 and involucrin were quantified. Finally, latanoprost ophthalmic solution or its vehicle was administered at suprapharmacologic doses (two 30 μL drops twice daily in 1 eye for 1 year in monkey eyes, and corneal pachymetry was performed at baseline and at weeks 4, 13, 26 and 52. Results In the 3-D corneal epithelial culture assays, there were no significant differences in cytotoxicity between the BAC-containing latanoprost and olopatadine ophthalmic solutions and BAC-free travoprost ophthalmic solution at either the 10- or 25-minute time points. The 3-D cultures expressed higher levels of corneal epithelial markers than the HCE-T monolayers, indicating a greater degree of differentiation. There were no significant differences between the corneal thickness of monkey eyes treated with latanoprost ophthalmic solution or its vehicle (both containing 0.02% BAC and untreated eyes. Conclusion The lack of cytotoxicity demonstrated in 3-D corneal cultures and in monkey studies suggests that the levels of BAC

  15. Linear attenuation (or absorption) coefficient of gamma radiation for dilute solutions of potassium chloride

    The mass attenuation and energy absorption coefficients are basic quantities used in calculations of photon energy transport and deposition for radiation dosimetry. This report describes a study of the concentration dependence of the attenuation of γ radiation of various energies by KCl solutions of different concentration. (author)

  16. REE and TPE sorption on strong-acid sulfocation exchanger KU-2 from nitric acid solutions

    Sorption of rare earths on strong acid sulfocationite KU-2, depending on solution acidity (0.1-2.0 mol/l nitric acid) and rare earths concentration, has been studied. It is ascertained that in solutions concentrated in terms of nitrate-ions, where formation of M(NO3)2+ and M(NO3)2+ complexes is possible, a seeming increase in the ionite capacity by approximately 20% is observed. 3 refs.; 1 fig.; 5 tabs

  17. Effect of phytic acid, ethylenediaminetetraacetic acid, and chitosan solutions on microhardness of the human radicular dentin

    Vineeta Nikhil; Shikha Jaiswal; Parul Bansal; Rohit Arora; Shalya Raj; Pulkit Malhotra

    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 befo...

  18. Self-consistent field theory investigation of the behavior of hyaluronic acid chains in aqueous salt solutions

    Nogovitsin, E. A.; Budkov, Yu. A.

    2012-04-01

    In this work we continue to develop a field-theoretic methodology, which combines the technique of Gaussian equivalent representation for the calculation of functional integrals with the continuous Gaussian thread model of flexible polymers for solving statistical-mechanical problems of polyelectrolyte solutions. We present new analytic expressions for the osmotic pressure, the potential of mean force, and the monomer-monomer pair distribution function, and employ them to investigate the structural and thermodynamic quantities of the polyelectrolyte system. We demonstrate the applicability of the method for systems of polyelectrolyte chains in which the monomers interact via a Yukawa-type pair potential. As a specific example, the present work focuses on aqueous solutions of hyaluronic acid with added salts NaCl and CaCl2. Hyaluronic acid is a high molecular weight linear polysaccharide, which has a multitude of roles in biological tissues. We conclude that the effect of sodium chloride and calcium chloride on the osmotic properties of hyaluronic acid solutions can be accounted for by their contributions to the ionic strength. Nevertheless, the effects of coiling and self-association can be stimulated in solution by added salt.

  19. Thermophysical properties of sodium nitrate and sodium chloride solutions and their effects on fluid flow in unsaturated media

    Xu, Tianfu; Pruess, Karsten

    2001-10-01

    Understanding movement of saline sodium nitrate (NaNO{sub 3}) waste solutions is important for assessing the contaminant migration near leaking waste storage tanks in the unsaturated zone at the Hanford site (Washington, USA). The purpose of this study is to contribute a basic understanding of effects of the thermophysical behavior of NaNO{sub 3} solutions on fluid flow in unsaturated media. We first present mathematical expressions for the dependence of density, viscosity, solubility and vapor pressure of NaNO{sub 3} solutions on both salt concentration and temperature, which were determined by fitting from published measured data. Because the previous studies of thermophysical behavior of sodium chloride (NaCl) solutions can provide a basis for those of NaNO{sub 3} solutions, we also present a comparison of thermophysical properties of both salt solutions. We have implemented the functional thermophysical properties of NaNO{sub 3} solutions into a new TOUGH2 equation-of-state module EWASG-NaNO{sub 3}, which is modified from a previous TOUGH2 equation-of-state module EWASG for NaCl. Using the simulation tool, we have investigated effects of the thermophysical properties on fluid flow in unsaturated media. The effect of density and viscosity of saline solutions has been long recognized. Here we focus our attention on the effect of vapor pressure lowering due to salinity. We present simulations of a one-dimensional problem to study this salinity-driven fluid flow. A number of simulations were performed using different values of thermal conductivity, permeability, and temperature, to illustrate conditions and parameters controlling these processes. Results indicate that heat conduction plays a very important role in this salinity-driven vapor diffusion by maintaining a nearly constant temperature. The smaller the permeability, the more water is transferred into the saline environment. Effects of permeability on water flow are also complicated by effects of capillary

  20. Solubility of proline-leucine dipeptide in water and in aqueous sodium chloride solutions from T = (288.15 to 313.15) K

    Solubility of proline-leucine dipeptide, in water and in aqueous sodium chloride solutions, was measured at T = (288.15, 298.15, 308.15 and 313.15) K as a function of electrolyte concentration m = (0.1, 0.25, 0.5, 0.75 and 1) mol . kg-1 of water. Solubility data has been evaluated from density measurements using a vibrating tube densimeter. It has been observed that sodium chloride renders the dipeptide proline-leucine more soluble in water. Salting-in coefficients and standard free energies of transfer of proline-leucine, from water to aqueous sodium chloride solutions, have been calculated from the solubility data. Standard enthalpies and entropies of transfer have also been estimated and interpreted in terms of electrostatic and hydrophobic perturbed domains in the hydration shells of the dipeptide and of the cation and anion of the salt, as a function of temperature and salt concentration

  1. Effects of applied potential on the fatigue behavior of Alloy 600 in sodium chloride solution

    The fatigue crack growth (FCG) rates of mill annealed Alloy 600 in 0.1 M NaCl solution, 25 C, were studied by a fracture mechanics test method and were affected by the applied potential, load frequency and load ratio. At an applied cathodic potential of -1,300mVSCE, the FCG rates increased with lowering, the load frequency and with increasing the load ratio. The enhanced FCG rate was found in the lower load frequencies (≤< 0.1 Hz) and was more significant with increasing the load ratio. The secondary cracks and transgranular fracture modes were observed on the fractured surfaces with applied cathodic potential. The possible hydrogen-assisted cracking mechanism on enhancing the FCG rates of Alloy 600 cathodically charged in 0.1 M NaCl solution, 25 C, is discussed in this paper. This study is pertinent to the fatigue cracking problems occurring in steam generator tubes of PWR

  2. Inhibiting effect of acetonitrile on oxygen reduction on polycrystalline pt electrode in sodium chloride solution

    Marinović Vedrana M.

    2012-01-01

    Full Text Available The oxygen reduction reaction (ORR was studied on the polycrystalline Pt electrode in 0.1 M NaCl electrolyte containing various amounts of acetonitrile (AcN. The state of the electrode surface was characterized by the cyclic voltammetry in oxygen free electrolytes, while ORR studies were performed on the polycrystalline Pt rotating disc electrode by the linear sweep voltammetry in oxygen saturated electrolytes. The acetonitrile is chemisorbed on Pt over a wide potential range, inhibiting both hydrogen adsorption and oxide formation. The extent of AcN chemisorption depends on its concentration in the solution. Initial potential of oxygen reduction is shifted negatively, while the ORR current is increasingly reduced with the increase of AcN concentration. Complete inhibition of ORR in the potential range of AcN and Cl-anion coadsorption is achieved for (0.1 M NaCl + 1 M AcN solution.

  3. Corrosion Fatigue Behavior of Duplex Stainless Steel in 3.5% Sodium Chloride Solution

    2001-01-01

    The corrosion fatigue behavior of duplex stainless steel (DSS) was studied at different cyclic stress levels in 3.5%NaCl (mass fraction, so as the follows) solution (pH=7) at 50℃. The results showed that DSS was susceptible to pitting corrosion and corrosion fatigue. Both intergranluar corrosion cracking and transgranlular corrosion cracking initiated at the bottom of pitting holes. Furthermore, the corrosion fatigue properties of DSS in 3.5%NaCl solution may be relatived to complex electrochemical and mechanical coupling effects between the three phases (austenite, ferrite and martensite), where martensite and ferrite were anodic in the corrosion cell and could be prone to cracking under certain condition.

  4. Exchange of uranium (6) ions on nitrogen-phosphorus-containing polyampholytes in chloride-fluoride solutions

    Uranium sorption from UO2Cl2 solutions containing HCl, NH4Cl and HF by polyampholytes ANKF-1, ANKF-2 and ANKF-3G is investigated. Effect of HCl, NH4Cl and HF in a wide concentration range is shown. On the basis of data on the sorption, results of analysis and IR spectroscopy conclusions are made on the composition of the ions sorbed and forms of their bond with functional groups. Mathematical model of the sorption process is suggested

  5. Influence of Heat Treatment on the Corrosion of Microalloyed Steel in Sodium Chloride Solution

    Asiful Hossain Seikh

    2013-01-01

    Microalloyed Steels find wide application in car bodies and other engineering parts because of its high strength as well as high ductility. Very fine grained microstructure is the reason behind the combination of strength and ductility. It has been reported that repeated quenching leads to further refining of microstructure. In the present investigation, corrosion resistance property of E34 microalloy steel has been studied in 3.5% NaCl solution in different microstructural conditions such as...

  6. Transurethral enucleation of large benign prostatic hyperplasia in sodium chloride solution

    I. N. Shvarev; Andreev, S. S.; V. V. Savich

    2016-01-01

    Background. Transurethral resection is a generally recognized treatment for small to medium-sized benign prostatic hyperplasia (BPH). Numerous original tools are proposed for surgery of large BPH. These include laser (holmium laser enucleation of the prostate) and transurethral (transurethral enucleation with bipolar (TUEB)) enucleation in 0.9 % NaCl solution, which are accompanied by removal of the maximum adenoma tissue volume, short-term recovery, and a substantially fewer early and late c...

  7. Electrochemical characterisation of a martensitic stainless steel in a neutral chloride solution

    Highlights: ► A better knowledge of the electrochemical behaviour of a martensitic stainless steel in bulk electrolyte was obtained. ► Quantitative parameters were obtained from impedance measurements. ► The study will be used as reference to investigate crevice corrosion using a thin layer cell. - Abstract: This paper focuses on the characterisation of the electrochemical behaviour of a martensitic stainless steel in 0.1 M NaCl + 0.04 M Na2SO4 solution and is a part of a study devoted to crevice corrosion resistance of stainless steels. Polarisation curves and electrochemical impedance measurements were obtained for different experimental conditions in bulk electrolyte. X-ray photoelectron spectroscopy (XPS) was used to analyse the passive films. At the corrosion potential, the stainless steel was in the passive state and the corrosion process was controlled by the properties of the passive film formed during air exposure. During immersion in the deaerated solution, the passive film was only slightly modified, whereas it was altered both in composition and thickness during immersion in the aerated solution. After cathodic polarisation of the stainless steel electrode surface, the oxide film was almost totally removed and the surface appeared to be uniformly active for oxygen reduction. The new passive film, formed at the corrosion potential, was enriched with iron species and less protective. Impedance diagrams allowed the characterisation of both the oxide film (high-frequency range) and the charge transfer process (low-frequency range).

  8. Combined effects of simulated acid rain and lanthanum chloride on chloroplast structure and functional elements in rice.

    Hu, Huiqing; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

    2016-05-01

    Acid rain and rare earth element (REE) pollution exist simultaneously in many agricultural regions. However, how REE pollution and acid rain affect plant growth in combination remains largely unknown. In this study, the combined effects of simulated acid rain and lanthanum chloride (LaCl3) on chloroplast morphology, chloroplast ultrastructure, functional element contents, chlorophyll content, and the net photosynthetic rate (P n) in rice (Oryza sativa) were investigated by simulating acid rain and rare earth pollution. Under the combined treatment of simulated acid rain at pH 4.5 and 0.08 mM LaCl3, the chloroplast membrane was smooth, proteins on this membrane were uniform, chloroplast structure was integrated, and the thylakoids were orderly arranged, and simulated acid rain and LaCl3 exhibited a mild antagonistic effect; the Mg, Ca, Mn contents, the chlorophyll content, and the P n increased under this combined treatment, with a synergistic effect of simulated acid rain and LaCl3. Under other combined treatments of simulated acid rain and LaCl3, the chloroplast membrane surface was uneven, a clear "hole" was observed on the surface of chloroplasts, and the thylakoids were dissolved and loose; and the P n and contents of functional elements (P, Mg, K, Ca, Mn, Fe, Ni, Cu, Zn and Mo) and chlorophyll decreased. Under these combined treatments, simulated acid rain and LaCl3 exhibited a synergistic effect. Based on the above results, a model of the combined effects of simulated acid rain and LaCl3 on plant photosynthesis was established in order to reveal the combined effects on plant photosynthesis, especially on the photosynthetic organelle-chloroplast. Our results would provide some references for further understanding the mechanism of the combined effects of simulated acid rain and LaCl3 on plant photosynthesis. PMID:26815371

  9. The chloride-channel blocker 9-anthracenecarboxylic acid reduces the nonlinear capacitance of prestin-associated charge movement.

    Harasztosi, Csaba; Gummer, Anthony W

    2016-04-01

    The basis of the extraordinary sensitivity and frequency selectivity of the cochlea is a chloride-sensitive protein called prestin which can produce an electromechanical response and which resides in the basolateral plasma membrane of outer hair cells (OHCs). The compound 9-anthracenecarboxylic acid (9-AC), an inhibitor of chloride channels, has been found to reduce the electromechanical response of the cochlea and the OHC mechanical impedance. To elucidate these 9-AC effects, the functional electromechanical status of prestin was assayed by measuring the nonlinear capacitance of OHCs from the guinea-pig cochlea and of prestin-transfected human embryonic kidney 293 (HEK 293) cells. Extracellular application of 9-AC caused reversible, dose-dependent and chloride-sensitive reduction in OHC nonlinear charge transfer, Qmax . Prestin-transfected cells also showed reversible reduction in Qmax . For OHCs, intracellular 9-AC application as well as reduced intracellular pH had no detectable effect on the reduction in Qmax by extracellularly applied 9-AC. In the prestin-transfected cells, cytosolic application of 9-AC approximately halved the blocking efficacy of extracellularly applied 9-AC. OHC inside-out patches presented the whole-cell blocking characteristics. Disruption of the cytoskeleton by preventing actin polymerization with latrunculin A or by decoupling of spectrin from actin with diamide did not affect the 9-AC-evoked reduction in Qmax . We conclude that 9-AC acts on the electromechanical transducer principally by interaction with prestin rather than acting via the cytoskeleton, chloride channels or pH. The 9-AC block presents characteristics in common with salicylate, but is almost an order of magnitude faster. 9-AC provides a new tool for elucidating the molecular dynamics of prestin function. PMID:26869218

  10. Study of benzotriazole as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

    Corrosion and inhibition studies on API 5LX65 carbon steel in chloride solution containing various concentrations of benzotriazole has been conducted at temperature of 70°C using Electrochemical Impedance Spectroscopy (EIS). Corroded carbon steel surface with and without inhibitor have been observed using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectroscopy (EDS). The objectives of this research are to study the performance of benzotriazole as corrosion inhibitors. The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H2S at different BTAH concentrations showed that corrosion rate of carbon steel decreases with increasing of BTAH concentrations from 0 to 10 mmol/l. The inhibition efficiency of BTAH was found to be affected by its concentration. The optimum efficiency obtained of BTAH is 93% at concentration of 5 mmol/l. The result of XRD and EDS analysis reveal the iron sulfide (FeS) formation on corroded carbon steel surface without inhibitor. The EDS spectrum show the Nitrogen (N) bond on carbon steel surface inhibited by BTAH

  11. Inefficacy of osmotic backwash induced by sodium chloride salt solution in controlling SWRO membrane fouling

    Farooque, A. Mohammed; Al-Jeshi, Subhi; Saeed, Mohamed O.; Alreweli, Ali

    2014-12-01

    A study was conducted to evaluate the efficacy of osmotic backwash induced by high salt (NaCl) concentration solution on feed side of seawater reverse osmosis (SWRO) membranes, online and offline, in controlling membrane fouling and therefore minimizing/eliminating the need for chemical cleaning. SWRO membranes were deliberately fouled by feeding seawater from an open intake located on the Arabian Gulf Coast without dosing chemicals. The fouled membranes were subjected to offline cleaning with the salt solution of up to 25 % concentration. Despite the partial removal of foulants from the membrane surface, SWRO membrane performance could not be restored, indicating the ineffectiveness of osmotic backwash in aiding offline salt cleaning. Similarly, online osmotic backwash was found to be not only ineffective in removing foulants from membrane surfaces but actually increased the fouling rate, as indicated by faster fouling rates compared to other cases. Although the driving force required for the osmotic backwash existed, the generated back flow proved to be insufficient to detach foulants from membrane surfaces. During the study period, the average SWRO membrane flux was maintained between 19 and 23 LMH, whereas the average generated back flow flux by high salt concentration solution was only 11 LMH, which was not adequate to remove foulants from membrane surfaces. Moreover, it seems that the membrane configuration as well as inherent microstructure of SWRO membrane places certain constraints on the osmotic backwash process and renders osmotic backwash ineffective in tackling SWRO membrane fouling. Hence, chemical cleaning is essential to restore SWRO membrane performance whenever fouling occurs, and the use of highly concentrated salt solution does not have any significant benefit. Membrane autopsy revealed only an insignificant accumulation of biofouling layer despite the absence of disinfection. However, it was shown that culturable biofilm bacteria species

  12. Uranium (VI) ion exchange on nitrogen-phosphorus-containing polyampholytes in chloride-fluoride solutions

    Pakholkov, V.S.; Denisova, L.A.; Richkov, V.A.; Roshchepkina, L.I.

    1988-09-01

    The adsorption of uranium form UO/sub 2/Cl/sub 2/ solutions containing HCl, NH/sub 4/Cl, and HF has been studied using polyampholyte resins ANKF-1, ANKF-2, and ANKF-3D. The effects of HCl, NH/sub 4/Cl, and HF over broad concentration ranges on uranium adsorption have also been investigated. Based on adsorption data and the results of elemental analysis and IR spectroscopy conclusions have been drawn concerning the composition of adsorbed ions and their binding forms with functional groups. A mathematical model to describe the adsorption process has been proposed.

  13. Mechanism of Cl2- formation during pulsed radiolysis of neutral aqueous solutions of alkali metal chlorides

    The kinetics of accumulation and destruction of Cl2- in pulsed radiolysis of neutral aqueous solutions of KCl has been investigated. It is assumed that the process mechanism includes the reactions [H3O+...OH]+Cl- → Cl+2H2O (1). It is shown that reaction (2) is the rate-limiting stage of formation of Cl2-. Using a computer the authors calculated the rate constants of reactions (2) and (3), which were found to be equal to 7.6x105 l/molxsec and 1.7x1010 l/molxsec, respectively

  14. Dephosphorization of Steelmaking Slag by Leaching with Acidic Aqueous Solution

    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.

  15. Gamma-irradiation of malic acid in aqueous solutions

    Negron-Mendoza, A.; Graff, R.L.; Ponnamperuma, C.

    1980-12-01

    The gamma-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 nonvolatile products. Thin layer chromatography 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 gamma-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.

  16. A Comparative Study on the Electrochemical Corrosion Behavior of Iron and X-65 Steel in 4.0 wt % Sodium Chloride Solution after Different Exposure Intervals

    El-Sayed M. Sherif

    2014-07-01

    Full Text Available In this work, the results obtained from studying the anodic dissolution of pure iron and API X-65 5L pipeline steel after 40 min and 12 h exposure period in 4.0 wt % NaCl solutions at room temperature were reported. Potential-time, electrochemical impedance spectroscopy, potentiodynamic polarization, and chronoamperometric current-time at constant potential techniques were employed. It has been found that the iron electrode corrodes in the chloride test solutions faster than the API X-65 5L steel does under the same conditions. Increasing the exposure period for the electrodes from 40 min to 12 h showed a significant reduction in the corrosion parameters for both iron and steel in the 4.0 wt % NaCl solution. Results together confirmed clearly that the X-65 steel is superior to iron against corrosion in sodium chloride solutions.

  17. Efficient saccharification by pretreatment of bagasse pith with ionic liquid and acid solutions simultaneously

    Highlights: • Bagasse pith was pretreated by BMIMCl solution containing HCl and water. • Hemicellulose was hydrolyzed to reducing sugars by HCl to maximize total sugar yield. • Cellulose was dissolved by BMIMCl and 95% of cellulose recovery was obtained. • The recovered cellulose was disrupted which is conducive to cellulase hydrolysis. • The total sugars yield is 89.9% obtained from pretreatment and cellulase hydrolysis. - Abstract: Hydrolysis of hemicellulose and disruption of cellulose during pretreatment process are conducive to the following cellulase hydrolysis performance. In this work, bagasse pith was first pretreated by 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) solution containing 0–1.2% hydrochloric acid (HCl) and 30% water. The water (30%) added into the acidic ionic liquid (IL) solutions led to an increase in the biomass loading up to a biomass/IL solutions ratio of 1:10 (wt.%). Hemicellulose was hydrolyzed to reducing sugars by HCl and cellulose was dissolved by [BMIM]Cl. In this process, 76.9% of hemicellulose conversion and 95% of cellulose recovery were obtained. The pretreated bagasse pith was then followed by hydrolysis with commercially available enzymes. The effects of pretreatment temperature, reaction time and acid concentration on cellulase hydrolysis of pretreated bagasse pith were investigated. Pretreatment of bagasse pith with [BMIM]Cl solutions containing 1.0% HCl at 120 °C for 30 min resulted in the glucose concentration of 92.3 g/l and yield of 94.5% after 72 h of cellulase hydrolysis. The maximum total reducing sugars yield reached to 89.9% after pretreatment and cellulase hydrolysis

  18. Influence of Heat Treatment on the Corrosion of Microalloyed Steel in Sodium Chloride Solution

    Asiful Hossain Seikh

    2013-01-01

    Full Text Available Microalloyed Steels find wide application in car bodies and other engineering parts because of its high strength as well as high ductility. Very fine grained microstructure is the reason behind the combination of strength and ductility. It has been reported that repeated quenching leads to further refining of microstructure. In the present investigation, corrosion resistance property of E34 microalloy steel has been studied in 3.5% NaCl solution in different microstructural conditions such as the as rolled one and three repeated quenched conditions. Weight loss, potentiodynamic polarization method, and electrochemical impedance spectroscopy (EIS techniques have been used. To reveal the corrosion resistance of different treated steels, some significant characterization parameters such as Ecorr, Icorr, Rp, and Rct in linear polarization and EIS curves were analyzed and compared. It is found that with repeated recrystallization grains become finer, and corrosion rate increases suggesting that a compromise has to strike between high mechanical property and corrosion rate.

  19. The photochemistry of neptunium in aqueous nitric acid solutions

    Photochemical reactions of Np(IV), (V) and (VI) have been investigated in nitric acid solutions using 254 and 300 nm excitation from standard mercury discharge lamps. Absorption spectrometry was used to monitor the concentrations of the various neptunium species in solution. In the absence of added reagents, all oxidation states of neptunium are converted to the pentavalent state. The effect of adding urea and mild reducing agents such as ethanol and hydrazine on the photolysis has also been examined. Quantum efficiencies for these reactions have been found to vary from 0.001 to 0.1, depending on the acid concentration, wavelength, and reaction conditions. (orig.)

  20. Solvent extraction of scandium from technical hydrochloric-acid solutions

    The process of scandium extraction from technical hydrochloric-acid solutions is studied using the method of mathematical planning of the experiment. The methematical models of linear regression equations for parameters of scandium extraction and coefficients of scandium-iron and scandium- aluminium separations, which describe adequately the process of scandium extraction with tributyl phosphate, are obtained. It is established that the acid concentration in the initial solution is of primary importance for the effects of scandium extraction and its separation from iron and aluminium during the extraction. The optimum conditions for scandium extraction are determined

  1. Calcium Chloride in Neonatal Parenteral Nutrition Solutions with and without Added Cysteine: Compatibility Studies Using Laser and Micro-Flow Imaging Methodology

    Robert K Huston; J Mark Christensen; Alshahrani, Sultan M.; Sumeia M Mohamed; Sara M Clark; Nason, Jeffrey A; Ying Xing Wu

    2015-01-01

    Background Previous studies of compatibility of calcium chloride (CaCl2) and phosphates have not included particle counts in the range specified by the United States Pharmacopeia. Micro-flow imaging techniques have been shown to be comparable to light obscuration when determining particle count and size in pharmaceutical solutions. Objective The purpose of this study was to do compatibility testing for parenteral nutrition (PN) solutions containing CaCl2 using dynamic light scattering and mic...

  2. Fabrication and icing property of superhydrophilic and superhydrophobic aluminum surfaces derived from anodizing aluminum foil in a sodium chloride aqueous solution

    Song, Meirong; Liu, Yuru; Cui, Shumin; Liu, Long; Yang, Min

    2013-10-01

    An aluminum foil with a rough surface was first prepared by anodic treatment in a neutral aqueous solution with the help of pitting corrosion of chlorides. First, the hydrophobic Al surface (contact angle around 79°) became superhydrophilic (contact angle smaller than 5°) after the anodizing process. Secondly, the superhydrophilic Al surface became superhydrophobic (contact angle larger than 150°) after being modified by oleic acid. Finally, the icing property of superhydrophilic, untreated, and superhydrophobic Al foils were investigated in a refrigerated cabinet at -12 °C. The mean total times to freeze a water droplet (6 μL) on the three foils were 17 s, 158 s and 1604 s, respectively. Thus, the superhydrophilic surface accelerates the icing process, while the superhydrophobic surface delays the process. The main reason for this transition might mainly result from the difference of the contact area of the water droplet with Al substrate: the increase in contact area with Al substrate will accelerate the heat conduct process, as well as the icing process; the decrease in contact area with Al substrate will delay the heat conduct process, as well as the icing process. Compared to the untreated Al foil, the contact area of the water droplet with the Al substrate was higher on superhydrophilic surface and smaller on the superhydrophobic surface, which led to the difference of the heat transfer time as well as the icing time.

  3. Some physical properties of chitosan in propionic acid solutions

    Rashid Atta Khan

    2007-01-01

    Surface tensions, contact angles and conductivities of propionic acid solutions containing different amounts of chitosan were measured at a room temperature to a temperature accuracy of 0.2. The value of critical coagulation concentration (CCC) was then obtained from the plots of contact angle and conductivity versus concentration. Viscosity of the solutions with different concentrations was also measured in this work at the same temperature and from the plot of viscosity against concentrati...

  4. Influence of humic acids in solution on uranium solvent extraction

    The harmful influence of humic acids in solution on uranium solvent extraction is investigated in this paper. The influence appears to be the poor phase separation and forming stable emulsion when uranium is extracted or stripped, and decreasing the loaded uranium in organic phase. The extractions of organic matter and solvent extraction of uranium were carried out for three sedimentary uranium ores. The results show that the stable emulsions of w/o or o/w type are formed separately with organic solvent containing tertiary amine or D2EHPA when uranium from liquors containing humic acid is extracted. Several humic acids of different molecular weight were fractionated by means of fractional solution containing varicus volume ratio of ethanol-ethylacetate. The physical characters and chemical composition of the humic acids were determined. It is found that there is distinct difference in emulsion-causing character among the humic acids with different molecular weight. The removal methods of humic acid from aqueous and organic solutions are discussed briefly

  5. The extraction of zinc and other minor metals from concentrated ammonium chloride solutions with D2EHPA and Cyanex 272

    Amer, S.

    1995-12-01

    Full Text Available A comparative study is made of the extractants D2EHPA and Cyanex 272 for the zinc and minor metal extraction from aqueous concentrated ammonium chloride solutions, as those of the leaching liquors of the CENIM-LNETI process. Extraction equilibrium data for zinc are presented as extraction isotherms at constant pH and at a temperature of 50 °C. Zinc extraction and coextraction of minor metal ions as Cu, Ca, Pb, Mg, Cd, Co, Ni and Hg are studied. Mercury does not extract from concentrated ammonium chloride solutions. Cyanex 272 shows a better selectivity for zinc with regard to the minor metals than D2EHPA, which is especially remarkable for calcium, the most coextracted element by D2EHPA. Nickel and cadmium coextraction is negligible for both extractants. The possible use of the Cyanex 272 as an alternative to D2EHPA is considered.

    Se realiza un estudio comparativo del comportamiento del D2EHPA y del Cyanex 272 durante la extracción del cinc y otros metales minoritarios de soluciones acuosas concentradas de cloruro amónico, como las de las soluciones de lixiviación del proceso CENIM-LNETI. Se presentan los datos de equilibrio de extracción del cinc en forma de isotermas de extracción a una temperatura de 50 °C y pH constante y se estudia la coextracción de los metales minoritarios Cu, Ca, Pb, Mg, Cd, Co, Ni y Hg. El mercurio no se extrae de las soluciones concentradas de cloruro amónico. La selectividad del Cyanex 272 para el cinc respecto de esos metales minoritarios es mejor que la del D2EHPA, siendo verdaderamente notable para el calcio, que es la impureza que más se coextrae con el D2EHPA. La coextracción de níquel y de cadmio es muy pequeña para ambos extractantes. Se considera la posibilidad del uso alternativo del Cyanex 272 en lugar del D2EHPA.

  6. Transurethral enucleation of large benign prostatic hyperplasia in sodium chloride solution

    I. N. Shvarev

    2016-01-01

    Full Text Available Background. Transurethral resection is a generally recognized treatment for small to medium-sized benign prostatic hyperplasia (BPH. Numerous original tools are proposed for surgery of large BPH. These include laser (holmium laser enucleation of the prostate and transurethral (transurethral enucleation with bipolar (TUEB enucleation in 0.9 % NaCl solution, which are accompanied by removal of the maximum adenoma tissue volume, short-term recovery, and a substantially fewer early and late complications.Objective: to evaluate the safety and efficiency of TUEB in patients with large BPH.Subjects and methods. TUEB was carried out in 58 patients with large BPH. Their mean age was 64 years. The gland size was ≥ 102 сm3. The residual urine volume in all the patients was more than 100 ml. One year later, the results of treatment were analyzed using the International Prostate Symptom Score (IPSS, Quality of Life (QoL Questionnaire, as well as from residual urine volume and remaining prostate tissue.Results. The mean time of surgery and enucleation was 90 and 55 min, respectively. The mean volume of removed adenoma tissue was 99 ml. By the end of month 2 following TUEB, there was a progressive reduction in the total IPSS and QoL scores from 35 to 7 and from 5 to 1, respectively, which preserved this trend by the end of a 1-year follow-up. study. The residual urine amount was less than 30 ml. The mean volume of the prostate tissue left was 8.5 сm3 and less than 11.0 сm3. The ultrasound anatomy of the prostatic urethra (transformation of thin-walled spherical TUR defect that is characteristic slit-like one resembles the inverted letter Y eventually formed by the end of the 1-year follow-up. Stricture of the urethra and contracture of the bladder neck were noted in none of the cases. Conclusion. TUEB is an alternative to open surgery in patients with the enlarged prostate. The use of isotonic NaCl solution as washing fluid allows one to plan

  7. Stability of succinylcholine chloride injection.

    Schmutz, C W; Mühlebach, S F

    1991-03-01

    The stability of succinylcholine chloride injection prepared by a hospital pharmacy was studied under a wide variety of conditions. Batches of succinylcholine chloride injection 10 mg/mL containing sodium chloride, methyl-4-hydroxybenzoate, hydrochloric acid, and water were prepared. Samples were tested for the effect of initial pH (3.0 and 4.2) and sterilization (steam treatment at 100 degrees C for 30 minutes and 121 degrees C for 20 minutes) on stability after three weeks; long-term stability under refrigeration (12, 17, and 23 months of storage at 4 degrees C); and the effect of storage temperature (4-6 degrees C, 20-26 degrees C, 35 degrees C, and 70 degrees C) and light exposure at various intervals up to 12 months. Samples were analyzed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). Unlike heating at 121 degrees C, heating at 100 degrees C produced no significant loss of succinylcholine chloride, independent of the initial pH. Succinylcholine chloride was hydrolyzed only minimally over 23 months if the solution was stored at 4-6 degrees C. A 10% loss of drug content occurred if solutions were kept at 20-26 degrees C for five months, at 35 degrees C for one month, or at 70 degrees C for one day. Initial degradation was slowed if the solution was protected from light. The assessments by TLC proved to be more sensitive than the HPLC measurements. Succinylcholine chloride injection sterilized at 100 degrees C for 30 minutes can be stored for up to five months at room temperature if protected from light. The preparation is stable for at least two years under refrigeration. PMID:2028996

  8. Adsorption of uranium (VI) from mixed chloride-fluoride solutions by anion-exchange resins

    Pakholkov, V.S.; Denisova, L.A.; Rychkov, V.N.; Kurnosenko, N.A.

    1988-03-01

    Experimental data are reported and discussed concerning the adsorption of uranium from 0.025 M solutions of UO/sub 2/Cl/sub 2/, containing HCl, HF, and NH/sub 4/Cl over a wide concentration range, using anion-exchange resins of varying basicities. UV and IR spectroscopic studies were conducted in order to clarify the chemical mechanism of uranium adsorption. Adsorption isotherms for all of the ion-exchange resins studied are convex in shape and can be described by the following equations: log K/sub d/ = a + b (-log C/sub e/), and log A = a + (b + 1) log C/sub e/, where A is the adsorptivity in mmole U/g; K/sub d/ is the distribution coefficient in mg/liter; and C/sub e/ is the equilibrium concentration of U in mmole/ml. General mathematical models have been obtained to describe the adsorption process; these consist of a system of regression equations derived from the results of a complete 2/sup 3/ factorial study.

  9. Corrosion Resistance and Pitting Behaviour of Low-Carbon High-Mn Steels in Chloride Solution

    Grajcar A.

    2016-06-01

    Full Text Available Corrosion resistance of the X4MnSiAlNbTi27-4-2 and X6MnSiAlNbTi26-3-3 type austenitic steels, after hot deformation as well as after cold rolling, were evaluated in 3.5% NaCl solution using potentiodynamic polarization tests. A type of nonmetallic inclusions and their pitting corrosion behaviour were investigated. Additionally, the effect of cold deformation on the corrosion resistance of high-Mn steels was studied. The SEM micrographs revealed that corrosion damage formed in both investigated steels is characterized by various shapes and an irregular distribution at the metallic matrix, independently on the steel state (thermomechanically treated or cold worked. Corrosion pits are generated both in grain interiors, grain boundaries and along the deformation bands. Moreover, corrosion damage is stronger in cold deformed steels in comparison to the thermomechanically treated specimens. EDS analysis revealed that corrosion pits preferentially nucleated on MnS and AlN inclusions or complex oxysulphides. The morphology of corrosion damage in 3.5% NaCl supports the data registered in potentiodynamic tests.

  10. Critical pitting and repassivation temperatures for duplex stainless steel in chloride solutions

    Deng Bo; Jiang Yiming; Gong Jia; Zhong Cheng; Gao Juan [Department of Material Science, Fudan University, Shanghai 200433 (China); Li Jin [Department of Material Science, Fudan University, Shanghai 200433 (China)], E-mail: jinli@fudan.edu.cn

    2008-06-30

    Both the critical pitting temperature (CPT) and critical repassivation temperature (T{sub r}) for two kinds of duplex stainless steels (DSS, namely UNS S31803 and UNS S32750) were investigated in 1 mol/L NaCl solution using the cyclic thermammetry method. Potentiodynamic anodic polarization technique was employed to validate the cyclic thermammetry technique. In addition, the site of pitting nucleated preferentially on the DSS had been confirmed by scanning electron microscopy (SEM). The results demonstrated that there exhibits a hysteresis loop in cyclic thermammetry curve, revealing that the propagating pits could repassivate during the cooling half-cycle. The CPT and T{sub r} for UNS S31803 were 59.6 deg. C and 36.5 deg. C, whilst the CPT and T{sub r} for UNS S32750 were 87.5 deg. C and 70.5 deg. C, respectively. Pitting was always observed preferentially in the austenite phase. The results can be partially explained based on the changes in chemical composition of ferrite and austenite phases. Moreover, a semi-quantitative model is proposed to explain the existence of T{sub r}.

  11. Environmentally Assisted Cracking of Alloy 7050-T7451 Exposed to Aqueous Chloride Solutions

    Braun, Reinhold

    2016-03-01

    The stress corrosion cracking (SCC) behavior of 7050-T7451 plate material was investigated in short-transverse direction performing constant load and constant extension rate tests. Smooth and notched tensile specimens were permanently immersed in substitute ocean water and in an aqueous solution of 0.6 M NaCl + 0.06 M (NH4)2SO4. Alloy 7050-T7451 exhibited high SCC resistance in both synthetic environments. However, conducting cyclic loading tests, environment-induced cracking was observed. Applying a sawtooth waveform, notched tensile specimens were strained under constant load amplitude conditions at constant displacement rates ranging from 2 × 10-6 to 2 × 10-4 mms-1. The stress ratio R = σ min/ σ max was 0.1 with maximum stresses of 300 and 400 MPa. When cyclically loaded in substitute ocean water, notched specimens failed predominantly by transgranular environment-induced cracking. Striations were observed on the cleavage-like facets. The number of cycles-to-failure decreased with decreasing displacement rate. A slope of 0.5 was obtained by fitting the logarithmic plot of number of cycles-to-failure vs nominal loading frequency, indicating a hydrogen embrittlement mechanism controlled by diffusion.

  12. Real surface area of the aluminium electrode in sodium chloride solution

    Z. RAKOCEVIC

    1999-11-01

    Full Text Available By combining the techniques of electrochemical slow potentiodynamic, AC impedance and atomic force microscopy (AFM, it was shown that the differences in the anodic dissolution rates of Al in 0.5 NaCl solutions as measured experimentally in the potential region between the corrosion and pitting potential, are mainly due to differences in surface roughness of the electrodes used. It was shown that mechanical grinding and polishing of the electrode surface with emery paper (400 grit and alumina polishing powder (f 0.25 mm can produce surfaces differing by a factor of 6 in the roughness factor Ra. By using AFM estimates of the roughness factors a true electrode capacitance of 4.63 µC cm-2 and thickness dox ~ 2.0 nm for the barrier layer of the surface film was estamited. The outer part of the film is porous, partly as amorphous Al(OH3, or crystalline bayerite (Al2O3.3H2O.

  13. Methanol oxidation at platinum electrodes in acid solution: comparison between model and real catalysts

    A. V. TRIPKOVIC

    2006-12-01

    Full Text Available Methanol oxidation in acid solution was studied at platinum single crystals, Pt(hkl, as the model catalyst, and at nanostructural platinum supported on high surface area carbon, Pt/C, as the real catalyst. The linear extrapolation method was used to determine the beginning of hydroxyl anion adsorption. Structural sensitivity of the adsorption was proved and a correlation with the onset of the methanol oxidation current was established at all catalysts. Bisulfate and chloride anions were found to decrease the methanol oxidation rate, but probably did not influence the reaction parth. The specific activity for the reaction increased in the sequence Pt(110 < Pt/C < Pt(111, suggesting that the activity of the supported Pt catalyst can be correlated with the activities of the dominating crystal planes on its surface.

  14. Structural characterization of zinc(II) chloride in aqueous solution and in the protic ionic liquid ethyl ammonium nitrate by x-ray absorption spectroscopy

    D'Angelo, Paola; Zitolo, Andrea; Ceccacci, Francesca; Caminiti, Ruggero; Aquilanti, Giuliana

    2011-10-01

    Extended x-ray absorption fine structure (EXAFS) spectroscopy has been used to investigate the species and structures existing in a series of ZnCl2-H2O-NaCl solutions with different chloride/zinc ratios and in a solution of ZnCl2 in the protic ionic liquid ethyl ammonium nitrate (EAN). The average coordination numbers and distances of zinc species were determined from the analysis of the EXAFS data. In aqueous solution the number of chloride ions tightly bounded to Zn2+ is significantly related to the chloride/zinc ratio, and no inner complex formation between Zn2+ and Cl- ions has been detected for low ZnCl2 concentration (0.1 and 0.2 M). Conversely, in the same concentration range (0.13 M) the ZnCl2 species do not dissociate in EAN and the Zn2+ first coordination shell has two chloride ions and is completed by two oxygen atoms of the nitrate anion. The results of this investigation show that notwithstanding the existence of similar characteristics between EAN and water, the solvation properties of the two solvents are markedly different.

  15. Removal and recovery of furfural, 5-hydroxymethylfurfural, and acetic acid from aqueous solutions using a soluble polyelectrolyte.

    Carter, Brian; Gilcrease, Patrick C; Menkhaus, Todd J

    2011-09-01

    In the cellulosic ethanol process, furfural, 5-hydroxymethylfurfural (HMF), and acetic acid are formed during the high temperature acidic pretreatment step needed to convert biomass into fermentable sugars. These compounds can inhibit cellulase enzymes and fermentation organisms at relatively low concentrations (≥ 1 g/L). Effective removal of these inhibitory compounds would allow the use of more severe pretreatment conditions to improve sugar yields and lead to more efficient fermentations; if recovered and purified, they could also be sold as valuable by-products. This study investigated the separation of aldhehydes (furfural and HMF) and organic acid (acetic acid) inhibitory compounds from simple aqueous solutions by using polyethyleneimene (PEI), a soluble cationic polyelectrolyte. PEI added to simple solutions of each inhibitor at a ratio of 1 mol of functional group to 1 mol inhibitor removed up to 89.1, 58.6, and 81.5 wt% of acetic acid, HMF, and furfural, respectively. Furfural and HMF were recovered after removal by washing the polyelectrolyte/inhibitor complex with dilute sulfuric acid solution. Recoveries up to 81.0 and 97.0 wt% were achieved for furfural and HMF, respectively. The interaction between PEI and acetic acid was easily disrupted by the addition of chloride ions, sulfate ions, or hydroxide ions. The use of soluble polymers for the removal and recovery of inhibitory compounds from biomass slurries is a promising approach to enhance the efficiency and economics of an envisioned biorefinery. PMID:21455937

  16. Mass transport in aqueous zinc chloride-potassium chloride electrolytes

    Leaist, D.G.

    1986-09-01

    Conductimetric and diaphragm cell techniques have been used to measure ternary diffusion coefficients for aqueous zinc chloride-potassium chloride solutions at 25/sup 0/C. At low concentrations where Zn/sup 2 +/ is the major zinc-transporting species, the diffusion-induced electric field along zinc chloride concentration gradients drives large co-current flows of potassium chloride. In concentrated solutions where a large proportion of zinc diffusses as anionic ZnCl/sub 3//sup -/ and ZnCl/sub 4//sup 2 -/ complexes, flow of zinc chloride generates counterflow of potassium chloride. If a sharp zinc chloride is formed in an otherwise uniform solution of potassium chloride, coupled diffusion can concentrate potassium ions within the diffusion boundary. Equations are developed to predict multicomponent transport coefficients for zinc chloride in supporting electrolytes.

  17. The effect of initial tonicity on freeze/thaw injury to human red cells suspended in solutions of sodium chloride.

    Pegg, D E; Diaper, M P

    1991-02-01

    Human red blood cells, suspended in solutions of sodium chloride, have been frozen to temperatures between -2 and -14 degrees C and thawed, and the extent of hemolysis was measured. In parallel experiments, red cells were exposed to similar cycles of change in the composition of the suspending solution, but by dialysis at 21 degrees C. The tonicity of the saline in which the cells were initially suspended was varied between 0.6x isotonic and 4x isotonic; some samples from each experimental treatment were returned to isotonic saline before hemolysis was measured. It was found that the tonicity of the saline used to suspend the cells for the main body of the experiment affected the amount of hemolysis measured: raising the tonicity from 0.6x to 1x to 2x reduced hemolysis, both in the freezing and in the dialysis experiments, whereas raising the tonicity further to 4x reversed that trend. There was little difference between the freeze/thaw and the dialysis treatments for the cells suspended in 1x or 2x saline, whether or not the cells were returned to isotonic conditions. However, the cells suspended in 0.6x saline showed greater damage from freezing and thawing than from the comparable change in the composition of the solution, whether or not they were returned to isotonic conditions. Cells that were suspended in 4x saline and exposed to changes in salt concentration by dialysis showed less hemolysis when they were assayed in the 4x solution than cells that had received the comparable freezing/thaw treatment, but when the experiment included a return to isotonicity, the two treatments gave similar results. Returning the cells to isotonic saline had a negligible affect on the cells in 0.6x and 1x saline, but caused considerable hemolysis in the 2x and 4x samples, more so after dialysis than after freezing and thawing. We conclude that cells suspended in 0.6x and 4x saline behave differently from cells suspended in 1x and 2x saline and hence that cells suspended in a

  18. The polarographic electroreduction of uranyl ion in arsenic acid solution

    The electroreduction of uranyl ion in arsenic acid studied by d.c. polarography shows one reduction wave at all the used arsenic acid concentrations corresponding to one electron reduction mechanism. At low arsenic acid concentration (0,1 - 0,3 M)UO2(ClO4)2 is reduced to HUO2AsO4. At higher acid concentration (0,6 M) the HUO2AsO4 molecules are reduced to UO2+ (pentavalent uranium). It is also reliable to study polarographic behaviour of uranyl ions in arsenic acid solutions up to pH 3,01. It is also possible to apply this method for the analytical determination of uranyl ion concentrations up to 2 mM. (Author)

  19. Electrochemical behaviour of brass in chloride solution concentrations found in eccrine fingerprint sweat

    Highlights: • Corrosion of brass in NaCl concentrations found in eccrine sweat was investigated. • Concentrations < 0.2 M produce a layer of mainly zinc oxide after 24 h. • A concentration of 0.2 M enables active corrosion of brass at room temperature. • 0.2 M NaCl gives both zinc and copper dissolution. • 24-h immersion of brass in 0.2 M NaCl gives an oxide film thickness of 1.3 nm. - Abstract: In this work, the corrosion properties of α phase brass immersed in concentrations of aqueous NaCl solutions that are typically found in eccrine fingerprint sweat and range between 0.01 M and 0.2 M have been analysed. Analysis methods employed were electrochemical techniques, X-ray photoelectron spectroscopy and optical profiling. For NaCl concentrations <0.2 M, active corrosion did not occur although, after a period of 24 h, a passivating layer of mainly zinc oxide formed. At a concentration of 0.2 M active corrosion did occur, with measured corrosion potentials consistent with both brass and copper dissolution. A 1 h contact time at this concentration (0.2 M) resulted in the formation of a zinc oxide passivating layer with the surface ratio of zinc oxide to copper oxide increasing with time. Film thickness was calculated to be of the order of 1.3 nm after 24 h contact. Formation of oxide layers on brass by fingerprint sweat as observed here may well have implications for the successful investigation of crime by the visualisation of corrosion fingerprint ridge patterns or the reduction of hospital environmental contamination by hand contact with brass objects such as door handles or taps

  20. Electrochemical behaviour of brass in chloride solution concentrations found in eccrine fingerprint sweat

    Bond, John W., E-mail: jwb13@le.ac.uk [Department of Chemistry, George Porter Building, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Lieu, Elaine [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)

    2014-09-15

    Highlights: • Corrosion of brass in NaCl concentrations found in eccrine sweat was investigated. • Concentrations < 0.2 M produce a layer of mainly zinc oxide after 24 h. • A concentration of 0.2 M enables active corrosion of brass at room temperature. • 0.2 M NaCl gives both zinc and copper dissolution. • 24-h immersion of brass in 0.2 M NaCl gives an oxide film thickness of 1.3 nm. - Abstract: In this work, the corrosion properties of α phase brass immersed in concentrations of aqueous NaCl solutions that are typically found in eccrine fingerprint sweat and range between 0.01 M and 0.2 M have been analysed. Analysis methods employed were electrochemical techniques, X-ray photoelectron spectroscopy and optical profiling. For NaCl concentrations <0.2 M, active corrosion did not occur although, after a period of 24 h, a passivating layer of mainly zinc oxide formed. At a concentration of 0.2 M active corrosion did occur, with measured corrosion potentials consistent with both brass and copper dissolution. A 1 h contact time at this concentration (0.2 M) resulted in the formation of a zinc oxide passivating layer with the surface ratio of zinc oxide to copper oxide increasing with time. Film thickness was calculated to be of the order of 1.3 nm after 24 h contact. Formation of oxide layers on brass by fingerprint sweat as observed here may well have implications for the successful investigation of crime by the visualisation of corrosion fingerprint ridge patterns or the reduction of hospital environmental contamination by hand contact with brass objects such as door handles or taps.

  1. The adsorption of methylene blue on montmorillonite from acid solutions

    Klika, Z.; Pustková, P.; Dudová, M.; Čapková, P.; Kliková, Ch.; Matys Grygar, Tomáš

    2011-01-01

    Roč. 46, č. 3 (2011), s. 461-471. ISSN 0009-8558 Institutional research plan: CEZ:AV0Z40320502 Keywords : montmorillonite * dissolution * acid solutions * methylene blue * adsorption Subject RIV: DD - Geochemistry Impact factor: 1.053, year: 2011

  2. Photolysis of Periodate and Periodic Acid in Aqueous Solution

    Sehested, Knud; Kläning, U. K.

    1978-01-01

    The photochemistry of periodate and periodic acid in aqueous solution was studied (i) by quantum yield measurements at low light intensity (ii) by flash photolysis, and (iii) by photolysis of glassy samples at 77 K. The photochemical studies were supplemented with pulse radiolysis studies of...

  3. Comparison of the corrosion behavior and surface morphology of NiTi alloy and stainless steels in sodium chloride solution

    Kožuh S.

    2016-01-01

    Full Text Available The corrosion behavior of NiTi alloy and stainless steels (AISI 316L and X2CrNiMoN22-5-3 in 0.9% sodium chloride (0.154 moll-1 solution was investigated using open circuit potential measurements, potentiodynamic polarization and electrochemical impedance spectroscopy measurements. Microstructural analyses before and after electrochemical tests were performed with the scanning electron microscopy (SEM equipped with energy dispersive spectrometry (EDS. The lowest corrosion current density has NiTi alloy and the extent of the passive range increased in the order AISI 316L stainless steel < NiTi alloy < X2CrNiMoN22-5-3 duplex stainless steel. The oxide film formed on all samples has a double-layer structure consisting of a barrier-type inner layer and a porous outer layer. Oxide films formed on the surface of steels mainly contains iron oxides and chromium oxide, while the surface film of the NiTi alloy mainly contains TiO2 oxide.

  4. Studies of removal of palladium(II) ions from chloride solutions on weakly and strongly basic anion exchangers.

    Hubicki, Z; Wołowicz, A; Leszczyńska, M

    2008-11-30

    Palladium and its compounds find wide application in industry as a catalytic agent in different manufacture processes. Recovery of precious metals from industrial wastes is difficult and time consuming but in spite of these disadvantages it becomes profitable. Palladium(II) ions sorption from various chloride solutions of the composition: 0.1-6.0M HCl-0.00056 M Pd(II), 1.0M ZnCl(2)-0.1M HCl-0.00056 M Pd(II), 1.0M AlCl(3)-0.1M HCl-0.00056 M Pd(II) on the weakly and strongly basic anion exchangers (Varion ATM, Varion ADM and Varion ADAM) was discussed. The sorption research of Pd(II) ions on these resins was carried out by means of static and dynamic methods. The dynamic processes were applied in order to determine the breakthrough curves of Pd(II) ions. Moreover, the working ion-exchange capacities as well as the weight and bed distribution coefficients were determined from the Pd(II) breakthrough curves. The recovery factors of Pd(II) ions (% R) depending on the phase contact time were obtained by means of static methods. The highest ion-exchange capacities for the 0.1-6.0M HCl-0.00056 M Pd(II) systems were obtained for the weakly basic ion-exchange resin Varion ADAM. PMID:18358602

  5. Chloride as tracer of solute transport in the aquifer-aquitard system in the Pearl River Delta, China

    Kuang, Xingxing; Jiao, Jiu Jimmy; Wang, Ya

    2016-02-01

    A 1D numerical model is constructed to investigate the impact of sedimentation and sea level changes on transport of Cl- in the aquifer-aquitard system in the Pearl River Delta (PRD), China. The model simulates the evolution of the vertical Cl- concentration profiles during the Holocene. Sedimentation is modeled as a moving boundary problem. Chloride concentration profiles are reconstructed for nine boreholes, covering a wide area of the PRD, from northwest to southeast. Satisfactory agreement is obtained between simulated and measured Cl- concentration profiles. Diffusion solely is adequate to reproduce the vertical Cl- concentration profiles, which indicates that diffusion is the regionally dominant vertical transport mechanism across the aquitards in the PRD. The estimated effective diffusion coefficients of the aquitards range from 2.0 × 10-11 to 2.0 × 10-10 m2/s. The effective diffusion coefficients of the aquifers range from 3.0 × 10-11 to 4.0 × 10-10 m2/s. Advective transport tends to underestimate Cl- concentrations in the aquitard and overestimate Cl- concentrations in the basal aquifer. The results of this study will help understand the mechanisms of solute transport in the PRD and other deltas with similar geological and hydrogeological characteristics.

  6. Removal of malachite green dye from aqueous solution using mesoporous silica synthesized from 1-octyl-3-methylimidazolium chloride ionic liquid

    Ekka, Basanti; Nayak, Soumitra Ranjan; Dash, Priyabrat; Patel, Raj Kishore

    2016-04-01

    In this research, mesoporous silica was synthesized via a modified sol-gel route using 1-octyl-3-methylimidazolium chloride and was employed to remove malachite green (MG) dye from aqueous solution. Subsequently, this material was characterized and identified by different techniques such as Fourier transform infrared spectroscopy (FT-IR), N2 adsorption-desorption method, scanning electron microscopy (SEM), and thermosgravimetric analysis (TGA). Unique properties such as high surface area and pore diameter, in addition to highly reactive atoms and presence of various functional groups make the mesoporous silica possible for efficient removal of malachite green (MG). In batch experimental set-up, optimum conditions for quantitative removal of MG by mesoporous silica was attained by varying different variables such as adsorbent dosage, initial dye concentration, contact time, and pH. Optimum values were set as pH of 8.0, 0.5 g of adsorbent at contact time of 120 min. The adsorption of MG follows the pseudo-second-order rate equation. Equilibrium data fitted well with the Freundlich model at all amount of adsorbent, while maximum adsorption capacity was 5.981 mg g-1 for 0.5 g mesoporous silica synthesized in IL.

  7. Flotation extraction of actinoids and lanthanoids from nitric acid solutions

    A study was made on possibility of using method of ion flotation for extraction of actinoids and lanthanoids from liquid radioactive wastes of spent fuel reprocessing. For this purpose ion flotation of thorium, plutonium (4), uranium (6) and gadolinium from aqueous nitric acid solutions (HNO3 concentration - from 0.01 up to 5.0 mol/l) was investigated, using lauryl phosphoric acid (LPA) as surfactant-collector. Growth of the degree of separation of metal ions with increase of LPA, introduced into the system, independently of acidity of solutions was established. Decrease of separation degree of uranium (6) and gadolinium with acidity growth and constancy of this parameter for plutonium (4) and thorium are observed at fixed mole LPA/metal ratio. Principle possibility of 100% flotation extraction of plutonium (4) and thorium independently of acidity of aqueous solutions is shown. Addition of 0.5 mol/l Ca(NO3)2 into the system doesn't produce sufficient effect on flotation extraction of thorium

  8. Corrosion of iron in highly acidic hydro-organic solutions

    In acidic water-organic solvents of ethylene glycol (EGOH), propylene glycol (PGOH), methanol (MeOH) and ethanol (EtOH), iron corrosion was studied by monitoring the corrosion potential, the potentiodynamic polarization curves and electrochemical impedance diagrams. In these aqueous glycols and alcoholic solutions containing HCl having concentrations of 0.5 up to 9 M, it has been shown by electrochemical analysis (I-E curves) that dissolution mechanism of iron is similar to that one in pure acidic aqueous solutions if only we take into account the relative amount of water in the medium. Based in our experimental data, water has an important role in the transfer kinetics of protons to the metallic electrode and limits electro dissolution rate of iron. When water quantity is sufficient at the metal surface, the acidity is a governing factor in the evolution of corrosion process

  9. Scientific Opinion on the safety assessment of the active substances iron powder, activated carbon, calcined kaolin, sodium chloride, polyacrylic acid, sodium salt, crosslinked and calcium chloride, for use as active system in food contact materials

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF

    2014-05-01

    Full Text Available This scientific opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety assessment of the active substances iron powder, activated carbon, calcined kaolin, sodium chloride, polyacrylic acid, sodium salt, crosslinked and calcium chloride, used in mixture which is packed into labels, for absorbing oxygen from the headspace surrounding packed food. All substances of this formulation have been evaluated and approved for use as additives in plastic food contact materials or as food supplements. Migration of substances from the labels and formation and release of volatile constituents are not expected under the intended conditions of use. The CEF Panel concluded that the use of substances iron powder, activated carbon, calcined kaolin, sodium chloride, polyacrylic acid, sodium salt, crosslinked and calcium chloride does not raise a safety concern when used in oxygen absorbers in labels, which prevent the physical release of their content into the food. When placed in the headspace of the packaging or when used in direct contact with foods, the labels should not intentionally or unintentionally come into direct contact with liquid foods or foods that have an external aqueous phase on the surface such as sliced fruits.

  10. Interactions of acidic solutions with sediments: a case study

    A methodology is presented for investigating the chemical interactions of acidic solutions with sediments. The MINTEQ geochemical computer code was used to predict solid-phase reactions that might occur when acidic solutions contact neutral sediments which, in turn, may control the concentrations of certain dissolved components. Results of X-ray diffraction analysis of laboratory samples of sediments that have been contacted with acidic uranium mill tailings solutions suggest gypsum and jarosite precipitated. These same mineralogical changes were identified in sediment samples collected from a drained uranium mill evaporation pond (Lucky Mc mine in Wyoming) with a 10-year history of acid attack. Geochemical modeling predicted that these same phases and several amorphous solids not identifiable by X-ray diffraction should have precipitated in the contacted sediments. An equilibrium conceptual model consisting of an assemblage of minerals and amorphous solid phases was then developed to represent a sediment column through which uranium mill tailings solutions were percolated. The MINTEQ code was used to predict effluent solution concentrations resulting from the reactions of the tailings solution with the assemblage of solid phases in the conceptual model. The conceptual model successfully predicted the concentrations of several of the macro-constituents (e.g., Ca, SO4, Al, Fe, and Mn), but was not successful in modeling the concentrations of trace elements. The lack of success in predicting the observed trace metal concentrations suggests that other mechanisms, such as adsorption, must be included in future models. The geochemical modeling methodology coupled with the laboratory and field studies should be applicable to a variety of waste disposal problems

  11. Ion flotation as a method of concentrating dilute solutions of uranium in sulfuric acid

    The results of experiments carried out in order to determine the possibility of extracting uranium by flotation from sulfuric acid solutions with the alkylpyridinium chlorides containing the following radicals is presented: decyl (DPC), dodecyl (doDPC), tridecyl (triDPC), tetradecyl (tetraDPC), pentadecyl (pentaDPC) and hexadecyl (hexaDPC); nicotinamide hydrobromides containing C10-C18 N-alkyl groups; hexadecylbenzyldimethylammonium bromide; bis(quaternary ammonium) salts of N,N' derivatives of hexamethylene- and ethylenediamine of the general formula ]1,2-[N,N'-bis(dimethyl)-N,N'-bis(decylacetato)]ethylenediammonium] dichloride (n = 2, R = C10H21) or ''ethonium (I)''; ]1,2-[N,N'-bis(dimethyl)-N,N'-bis(decylacetato)]hexamethylene-diammonium] dichloride (n = 6, R = C10H21) or ''ethonium (II)''; ]1,2-[N,N'-bis(dimethyl)-N,N'-bis(dodecylacetato)]hexamethylenediammonium] dichloride (n = 6, R = C12H25) or ''ethonium (III).'' Uranyl sulfate solutions of 0.005% concentration were used for the investigation. The solution pH was varied in the range 0.5-4.0. The sulfate-ion concentration was 0.1 g-ion/liter. The collectors (the surfactants listed above) were introduced into the uranium-containing test solutions in the form of 0.4% aqueous solutions, in the stoichiometric amounts required for binding UO2(SO4)34- anions. Flotation treatment of the solutions was continued for 20 min in the apparatus described in previous reports. The uranium and collector contents in the solutions were determined by standard methods. The zeta potentials of the sublate particles were determined electrophoretically

  12. Determination of dissociation constants of chloride complex acids of bivalent cobalt, zinc, copper and cadmium in TBP from extraction data

    Prokuev, V.A.; Belousov, E.A. (Leningradskij Tekhnologicheskij Inst. (USSR); Petrozavodskij Gosudarstvennyj Univ. (USSR))

    1980-12-01

    The calculated method of determining constants of dissociation complex acids of a number of metals (cobalt, copper, zinc and cadmium) in TBP on the basis of known values of element distribution coefficients and degrees of formation of extractive complexes in aqeuous solutions of hydrochloric acid at 25 deg C is suggested. The results of calculations are presented in a table. For H/sub 2/CdCl/sub 4/ the dissociation constant is (10sup(3)Ksub(D)=1.3).

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

    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

  14. The reducibility of sulphuric acid and sulphate in aqueous solution

    In connection with the Swedish project for final storage of spent fuel elements it was necessary to assess whether dissolved sulphate can corrode the copper canister. A simple reaction between copper and sulphate is thermodynamically impossible, but copper can react to give copper sulphide if an additional electron donor such as iron(II) is available. The problem was extended to the more general question of the reducibility of sulphur(VI) in dilute aqueous solution. Chemical reduction of sulphate does not take place in dilute solution at temperatures below 100oC. In experiments on the reduction of sulphates under hydrothermal conditions a reaction only takes place at temperatures above 275-300oC. The oxidising action of sulphuric acid on metals becomes perceptible only at acid concentrations over 45-50%. In experiments on the cathodic reduction of 74% sulphuric acid the formation of hydrogen sulphide and elementary sulphur starts, depending on the current density, at 50-130oC, and polarographic measurements suggest that the reducible species is not the hydrogen sulphate ion but molecular sulphuric acid. The resistance of copper to oxygen-free sulphuric acid up to a concentration of 60% is well-known. Numerous processes in industrial electrochemistry take place in sulphuric acid or sulphate electrolytes. The reversible metal/metal-sulphate electrodes of lead and cadmium are unstable relative to the corresponding metal sulphides. Nevertheless the reversible lead sulphate electrode does not fail from sulphide formation. All these facts confirm that sulphur(VI) in dilute solution is completely inert towards chemical reducing agents and also to cathodic reduction. Thus corrosion of copper by sulphate under final-storage conditions and in the absence of sulphate reducing bacteria can be almost certainly be ruled out. (author) 5 figs., 85 refs

  15. PHOTO-INDUCED DOPED POLYANILINE BY THE VINYLIDENE CHLORIDE AND METHYL ACRYLATE COPOLYMER AS PHOTO ACID GENERATOR

    LI Suzhen; WAN Meixiang

    1997-01-01

    The emeraldine base form of polyaniline (PANI) can be doped by a photo-induced doping method. In this method a copolymer of vinylidene chloride and methyl acrylate (VCMAC) was used as photo acid generator which can release proton when it is exposed to ultraviolet light (λ = 254 nm). The structure of PANI-VCMAC system before and after irradiation was characterized by elemental analysis, IR, XPS, and SEM images. Results obtained indicate that the photo-induced doping characteristics, such as doping position and type of charge carriers, are similar to that of PANI doped with HCl. The poor roomtemperature conductivity (~ 10-5S/cm) of PANI-VCMAC system after irradiation may be due to low doping degree (~pH= 3) and the difference in morphology as compared with PANI-HCl film.

  16. Spectrophotometric determination of microamounts of thorium with thorin in the presence of cetylpyridinium chloride as surfactant in perchloric acid

    A simple and more sensitive spectrophotometric method is developed for determination of thorium using thorin as a chromogenic reagent in the presence of cetylpyridinium chloride (CPC) in perchloric acid. The reaction was instantaneous and complex was found stable for 168 h. A significant bathochromic shift was noted in the presence of CPC. The determination range was enhanced from 25 to 30 μg mL-1 with molar absorptivity of 2.95 × 104 L mol-1 cm-1 at 25 ± 5 deg C. Sandell's sensitivity was calculated to be 6.8 ng cm-2 at 581 nm. Relative standard deviation was reduced from 4.25 to 2.5. The interference of Ni2+, Mn2+, Sn4+, phosphate, EDTA, sulphate and tartrate has been reduced significantly in the presence of surfactant. The validity of the proposed method was tested by determining thorium in Certified Reference Materials. (author)

  17. Influence of salicylic acid on rubisco and rubisco activase in tobacco plant grown under sodium chloride in vitro

    Lee, So Young; Damodaran, Puthanveettil Narayanankutty; Roh, Kwang Soo

    2014-01-01

    The present study was designed to evaluate the influence of salicylic acid (SA) on the growth of salt stress (sodium chloride) induced in tobacco plants. In addition, quantification of rubisco and rubisco activase contents of the plants was also determined in treatments with the control, 10−4 mM SA, 50 mM NaCl, 100 mM NaCl, 150 mM NaCl, SA + 50 mM NaCl, SA + 100 mM NaCl and SA + 150 mM NaCl, respectively after in vitro culture for 5 weeks. The growth of the tobacco plant decreased in 50 mM an...

  18. Ozonation of Sulfur Dioxide in Sulphuric Acid Solution

    LIU Limei; ZHANG Shuting; L(U) Xuebin; YU Xiaoyan; ZHI Suli

    2013-01-01

    In this study,the oxidation rates of sulfur dioxide (SO2) in sulphuric acid solution by ozone and oxygen were compared,and the oxidation mechanism of ozone on SO2 was investigated.The results showed that the oxidation-reduction potential of the acidic solution was enhanced,the transformation rate of sulfuric acid to sulphuric acid was increased and the absorption driving force was improved in the presence of ozone.By comparing the amount of sulfate ions measured in the experiments and the theoretical amount of sulfate ions calculated from the amount of ozone consumed in the reaction,it can be confirmed that oxygen free radicals from dissociation of ozone are reactive as an efficient oxidant and oxygen from ozone generator participates in the reaction with SO2.0.602tmol of effective oxygen was introduced into the reaction by one mole of ozone in 10.15 min at sulphuric acid concentration of 3% (by mass),SO2 concentration of 1.33% (by volume) and oxygen flow rate of 1.5 L·min-1 from ozone generator.

  19. Some physical properties of chitosan in propionic acid solutions

    Rashid Atta Khan

    2007-10-01

    Full Text Available Surface tensions, contact angles and conductivities of propionic acid solutions containing different amounts of chitosan were measured at a room temperature to a temperature accuracy of 0.2. The value of critical coagulation concentration (CCC was then obtained from the plots of contact angle and conductivity versus concentration. Viscosity of the solutions with different concentrations was also measured in this work at the same temperature and from the plot of viscosity against concentration; the intrinsic viscosity was determined by extrapolation.

  20. Structural effects and microheterogeneity in concentrated solutions and their role in the formation of chloride complexes of cadmium

    Processes of cadmium chloride complexes formation in the systems CdAn2-Nacl-H2O, where An = Cl-, ClO4-, NO3-, were studied by the methods of polythermal solubility, 1H NMR and Raman spectroscopy. It was ascertained that in the range of pre-eutectic concentrations of cadmium salts all possible forms of cadmium chloride complexes are formed, while in post-eutectic range the process of the complex formation is of structurally enforced character. Mechanisms of chloride complexes formation in perchlorate and nitrate systems are suggested. The conclusion is made that in contrast to chloride system the nitrate and perchlorate systems in the presence of NaCl are characterized by structural microheterogeneity

  1. Extraction behavior of cerium by tetraoctyldiglycolamide from nitric acid solutions

    The diamide N,N,N',N'-tetraoctyldiglycolamide (TODGA) was synthesized and characterized. The prepared TODGA was applied for extraction of Ce(III) from nitric acid solutions. The equilibrium studies included the dependencies of cerium distribution ratio on nitric acid, TODGA, nitrate ion, hydrogen ion and cerous ion concentrations. Analysis of the results indicates that the main extracted species is Ce(TODGA)2(NO3)3HNO3. The capacity of Ce loading is approximately 45 mmol/L for 0.1 M solution of TODGA in n-hexane. Finally, the thermodynamic parameters were calculated: K (25 deg C) = 3.8 x 103, ΔH = -36.7 ± 1.0 kJ/mol, ΔS = -54.6 ± 3.0 J/K mol, and ΔG = -20.4 ± 0.1 kJ/mol. (author)

  2. DC diaphragm discharge in water solutions of selected organic acids

    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

  3. Ternary mutual diffusion in aqueous (ethambutol dihydrochloride + hydrochloric acid) solutions

    Highlights: • Ternary diffusion coefficients for aqueous system ethambutol dihydrochloride and hydrochloric acid. • Diffusion of ethambutol dihydrochloride driven by hydrochloric acid gradients. • Coupled diffusion as indicated by cross-diffusion coefficients. - Abstract: Ternary mutual diffusion coefficients measured by the Taylor dispersion method are reported for aqueous solutions of {ethambutol dihydrochloride (1) + HCl (2)} at 25 °C and various carrier solution compositions. Mutual diffusion coefficients estimated from limiting ionic conductivities using Nernst equations are used to discuss the composition dependence of the measured diffusion coefficients. 1H NMR studies, combined with DFT calculations, confirm a fully extended conformation for the diprotonated form of the drug present under these conditions, and are consistent with an electrostatic mechanism for the strongly coupled diffusion of diprotonated ethambutol and HCl

  4. The electrochemical behaviour of stainless steel AISI 304 in alkaline solutions with different pH in the presence of chlorides

    Highlights: → The passivation and passivation breakdown of AISI 304 in alkaline solutions with different pH was studied. → The electrochemical behaviour and the corrosion resistance in chloride environments were evaluated using d.c. potentiodynamic polarization and electrochemical impedance spectroscopy. → The results were modelled using a hierarchically distributed circuit and revealed a more susceptible surface at pH 9. → The passive film characterization was carried out by SEM and EDS analysis, revealing the existence of MnS inclusions and the increase of Cr/Fe ratio in the attacked areas, preferably the vicinity of those inclusions. - Abstract: Nowadays, stainless steel reinforcements appear as an effective solution to increase the durability of reinforced concrete structures exposed to very aggressive environments. AISI 304 is widely used for this purpose. Although the improved durability of reinforcing AISI 304, when compared to carbon steel, there is a high probability of pitting susceptibility in the presence of chlorides. Thus, the present work aims at studying the passivation and passivation breakdown of AISI 304 in alkaline solutions of different pH (pH from 13 to 9), simulating the interstitial concrete electrolyte. These solutions were contaminated with different concentrations of chloride ions (3% and 10%, as NaCl). The electrochemical behaviour was evaluated by d.c. potentiodynamic polarization and by electrochemical impedance spectroscopy (EIS). The morphological features and the changes observed in the surface composition were evaluated by Scanning Electron Microscopy (SEM) together with EDS chemical analysis. The results evidence that pH plays an important role in the evolution of the film resistance and charge transfer processes. Moreover, the effect is highly dependent upon the chloride content and immersion time.

  5. Fick's 2nd law - Complete solutions for chloride ingress into concrete – with focus on time dependent diffusivity and boundary condition

    Frederiksen, Jens M.; Mejlbro, Leif; Nilsson, Lars-Olof

    2009-01-01

    This report focuses on models of chloride ingress into concrete that are based on mathematical solutions of Fick's second law. In recent years a lot of confusion has been identified concerning these models. In some cases time-dependencies of diffusivity have been used in a mathematically incorrect way. In other cases field and laboratory data from one way of describing the time-dependency of these diffusivities has been used in models that are based on another model. This is now clarified...

  6. Pulse Radiolysis of Adrenaline in Acid Aqueous Solutions

    Gohn, M.; Getoff, N.; Bjergbakke, Erling

    1976-01-01

    Pulse radiolysis of adrenaline in acid aqueous solutions (pH 1–3) was carried out. The rate constants for the reactions of adrenaline with H and OH were determined: k(H + adr.) = (0·9±0·1) × 109 dm3 mol−1s−1; k(OH + adr.) = (1·65±0·15) × 1010 dm3 mol−1s−1. The H-adduct of adrenaline has two λmax...

  7. Solubility of chlorine in aqueous hydrochloric acid solutions.

    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

  8. Adsorption of Rh(III) complexes from chloride solutions obtained by leaching chlorinated spent automotive catalysts on ion-exchange resin Diaion WA21J

    It was found that Rh, Pd and Pt contained in the spent ceramic automotive catalysts could be effectively extracted by dry chlorination with chlorine. In order to concentrate Rh(III) ions contained in the chloride solutions obtained, thermodynamic and kinetics studies for adsorption of Rh(III) complexes from the chloride solutions on an anionic exchange resin Diaion WA21J were carried out. Rh, Pd, Pt, Al, Fe, Si, Zn and Pb from the chloride solution could be adsorbed on the resin. The distribution coefficients (Kd) of Rh(III) decreased with the increase in initial Rh(III) concentration or in adsorption temperature. The isothermal adsorption of Rh(III) was found to fit Langmuir, Freundlich and Dubinin-Kaganer-Radushkevich models under the adsorption conditions. The maximum monolayer adsorption capacities Qmax based on Langmuir adsorption isotherms were 6.39, 6.61 and 5.81 mg/g for temperatures 18, 28 and 40 deg. C, respectively. The apparent adsorption energy of Rh was about -7.6 kJ/mol and thus Rh(III) adsorption was a physical type. The experimental data obtained could be better simulated by pseudo-first-order kinetic model and the activation energy obtained was 6.54 J/mol. The adsorption rate of Rh(III) was controlled by intraparticle diffusion in most of time of adsorption process.

  9. Effect of the cation model on the equilibrium structure of poly-L-glutamate in aqueous sodium chloride solution

    Marchand, Gabriel; Soetens, Jean-Christophe; Jacquemin, Denis; Bopp, Philippe A.

    2015-12-01

    We demonstrate that different sets of Lennard-Jones parameters proposed for the Na+ ion, in conjunction with the empirical combining rules routinely used in simulation packages, can lead to essentially different equilibrium structures for a deprotonated poly-L-glutamic acid molecule (poly-L-glutamate) dissolved in a 0.3M aqueous NaCl solution. It is, however, difficult to discriminate a priori between these model potentials; when investigating the structure of the Na+-solvation shell in bulk NaCl solution, all parameter sets lead to radial distribution functions and solvation numbers in broad agreement with the available experimental data. We do not find any such dependency of the equilibrium structure on the parameters associated with the Cl- ion. This work does not aim at recommending a particular set of parameters for any particular purpose. Instead, it stresses the model dependence of simulation results for complex systems such as biomolecules in solution and thus the difficulties if simulations are to be used for unbiased predictions, or to discriminate between contradictory experiments. However, this opens the possibility of validating a model specifically in view of analyzing experimental data believed to be reliable.

  10. Contribution to the study to the stress corrosion susceptibility of austenitic stainless steel AISI 304 in aqueous solutions containing chlorides

    The anodic behaviour of type 304 austenitic stainless steel, stressed in aqueous neutral and acid NaCl solutions, was studied. The experimental technique of the straining electrode, with constant speed and high strain rate, was applied at room temperature and at 900C. The current density on the bare metal, which is exposed to the medium during the straining the specimen, was determined at various potentials for 1N; 0,1N and 0,001N NaCl, at both temperatures, and for 1N H2SO4 + 0,1N NaCl at room temperature. In the 1N NaCl solution, tests were also carried with slightly sensitizes material at 250C and 900C. The possible crack propagation rates were estimated from these data, and parameters related with stress corrosion cracking susceptibility were analised. Potentiodynamic polarization curves were done at several potential scanning rates with and without simultaneous straining of the electrode at the same temperature, in some of the NaCl concentrations, with the aim of comparing the current values with those found in the method described above. These curves were also performed in boiling MgCl2 solutions with and without addition of NaNO3 with the purpose of compare its stress corrosion prognostic capacity in relation of that other types of tests reported. (Author)

  11. Synthesis of C7-C16-alkyl glycosides in the presence of tin(IV) chloride as a Lewis acid catalyst

    STANIMIR KONSTANTINOVIC; JASMINA PREDOJEVIC; ZORICA PETROVIC; ALEKSANDRA SPASOJEVIC; BILJANA DIMITRIJEVIC; GRADIMIR MILOSEVIC

    1999-01-01

    The Lewis acid catalyzed glycosylation reaction of b-peracetylated sugar derivatives (glucose, galactose, xylose, maltose or lactose) with fatty alkanols is used for the synthesis of C7-C16-alkyl glycosides. The process occurs under the influence of tin(IV) chloride.

  12. Thermochemical comparisons of homogeneous and heterogeneous acids and bases. 1. Sulfonic acid solutions and resins as prototype Broensted acids

    Arnett, E.M.; Haaksma, R.A.; Chawla, B.; Healy, M.H.

    1986-08-06

    Heats of ionization by thermometric titration for a series of bases (or acids) can be used to compare solid acids (or bases) with liquid analogues bearing the same functionalities in homogeneous solutions. The method is demonstrated for Broensted acids by reacting a series of substituted nitrogen bases with solutions of p-toluenesulfonic acid (PTSA) in acetonitrile and with suspensions of the microporous polymeric arylsulfonic acid resin-Dowex 50W-X8 in the same solvent. Under well-controlled anhydrous conditions there is a good correlation (r = 0.992) between the heats of reaction of the bases with the homogeneous and heterogeneous acid systems, but the homogeneous system gives a more exothermic interaction by 3-4 kcal mol/sup -1/ for a series of 29 substituted pyrimidines, anilines, and some other amines. This difference may be attributed to homohydrogen bonding interactions between excess acid and sulfonate anion sites which are more restricted geometrically in the resin than in solution. Other factors which affect the enthalpy change for the acid-base interaction are the acid/base ratio, the water content of the sulfonic acid, the solvent, and the resin structure (e.g., microporous vs. macroporous). Steric hindrance in the base does not differentiate solid from homogeneous acid. In addition to the use of titration calorimetry, heats of immersion are reported for the Dowex-arylsulfonic acid resins and the Nafion-perfluorinated sulfonic acid resin in a series of basic liquids. The results are compared with each other and with those from a previous study of several varieties of coal.

  13. A novel digestion method based on a choline chloride-oxalic acid deep eutectic solvent for determining Cu, Fe, and Zn in fish samples.

    Habibi, Emadaldin; Ghanemi, Kamal; Fallah-Mehrjardi, Mehdi; Dadolahi-Sohrab, Ali

    2013-01-31

    A novel and efficient digestion method based on choline chloride-oxalic acid (ChCl-Ox) deep eutectic solvent (DES) was developed for flame atomic absorption spectrometry (FAAS) determination of Cu, Zn, and Fe in biological fish samples. Key parameters that influence analyte recovery were investigated and optimized, using the fish protein certified reference material (CRM, DORM-3) throughout the procedure. In this method, 100 mg of the sample was dissolved in ChCl-Ox (1:2, molar ratio) at 100°C for 45 min. Then, 5.0 mL HNO(3) (1.0 M) was added. After centrifugation, the supernatant solution was filtered, diluted to a known volume, and analyzed by FAAS. Under optimized conditions, an excellent agreement between the obtained results and the certified values was observed, using Student's t-test (P=0.05); the extraction recovery of the all elements was greater than 95.3%. The proposed method was successfully applied to the determination of analytes in different tissues (muscle, liver, and gills) having a broad concentration range in a marine fish sample. The reproducibility of the method was validated by analyzing all samples by our method in a different laboratory, using inductively coupled plasma optical emission spectrometry (ICP-OES). For comparison, a conventional acid digestion (CAD) method was also used for the determination of analytes in all studied samples. The simplicity of the proposed experimental procedure, high extraction efficiency, short analysis time, lack of concentrated acids and oxidizing agents, and the use of safe and inexpensive components demonstrate the high potential of ChCl-Ox (1:2) for routine trace metal analysis in biological samples. PMID:23327946

  14. Recovery of uranium from different acidic solutions by di-nonyl phenyl phosphoric acid (DNPPA) and TOPO

    The extraction mechanism of uranium with DNPPA in combination with TOPO has been established from different acidic media. The extraction order of uranium from these media has been found as perchlorate>nitrate>chloride>sulphate>phosphate. Based on these results extraction of uranium from samples of leach liquors generated in the plant has been carried out and >99% recovery was obtained

  15. Photometric estimation of plutonium in product solutions and acid waste solutions using flow injection analysis technique

    Flow injection analysis technique is employed for the measurement of plutonium concentrations in product nitrate solutions by measuring the absorbance of Pu(III) at 565 nm and of Pu(IV) at 470 nm, using a Metrohm 662 photometer, with a pyrex glass tube of 2 nm (ID) inserted in the light path of the detector serving as a flow cell. The photometer detector never comes in contact with radioactive solution. In the case of acid waste solutions Pu is first purified by extraction chromatography with 2-ethyl hexyl hydrogen 2 ethyl hexyl phosphonate (KSM 17)- chromosorb and the Pu in the eluate in complexed with Arsenazo III followed by the measured of absorbance at 665 nm. Absorbance of reference solutions in the desired concentration ranges are measured to calibrate the system. The results obtained agree with the reference values within ±2.0%. (author). 3 refs., 1 tab

  16. Evaluation of Chromate as Dezincification Inhibitor for α-brass (Cu/Zn : 64/36) in 3% Chloride Buffer Solutions

    H. H. Rehan; N.A. Al-Moubarak; H.A. Al-Rafai

    2003-01-01

    The inhibition behavior of chromate ions towards corrosion and dezincification of α-brass (Cu/Zn: 64/36) in acetate buffer solutions (pH 2.4, 7.0 and 8.5) containing 3% sodium chloride was studied. Weight loss and solution analysis were used for a long period (four weeks) and electrochemical polarization for a short period (one hour). Chromate accelerated corrosion and dezincification at pH 2.4 by acting as depolarizer but chromate suppressed efficiently the corrosion and dezincification...

  17. Micellar solubilization in strongly interacting binary surfactant systems. [Binary surfactant systems of: dodecyltrimethylammonium chloride + sodium dodecyl sulfate; benzyldimethyltetradecylammonium chloride + tetradecyltrimethylammonium chloride

    Treiner, C. (Universite Pierre et Marie Curie, Paris (France)); Nortz, M.; Vaution, C. (Faculte de Pharmacie de Paris-sud, Chatenay-Malabry (France))

    1990-07-01

    The apparent partition coefficient P of barbituric acids between micelles and water has been determined in mixed binary surfactant solutions from solubility measurements in the whole micellar composition range. The binary systems chosen ranged from the strongly interacting system dodecyltrimethylammonium chloride + sodium dodecyl sulfate to weakly interacting systems such as benzyldimethyltetradecylammonium chloride + tetradecyltrimethyammonium chloride. In all cases studied, mixed micelle formation is unfavorable to micellar solubilization. A correlation is found between the unlike surfactants interaction energy, as measured by the regular solution parameter {beta} and the solute partition coefficient change upon surfactant mixing. By use of literature data on micellar solubilization in binary surfactant solutions, it is shown that the change of P for solutes which are solubilized by surface adsorption is generally governed by the sign and amplitude of the interaction parameter {beta}.

  18. Green process for adipic acid synthesis: oxidation by hydrogen peroxide in water micromelusions using Benzalkonium Chloride C12-14 surfactant

    Lesage, Geoffroy; Quesada-Peñate, Isariebel; Cognet, Patrick; Poux, Martine

    2012-01-01

    Adipic acid was synthesized by the oxidation of cyclohexene using 30% hydrogen peroxide in a microemulsion in the presence of sodium tungstate as catalyst. The proposed green process is environmentally friendly since catalyst and surfactant are recycled and pure adipic acid is produced in high yield (70% to 79%). Microemulsions are used as a “green solvent” and give a better contact between the phases. Alkyldimethylbenzylammonium chloride (C12-C14) was used as a surfactant for the generation ...

  19. Separation of ruthenium from nitric acid solutions using carbon tetrachloride

    The noble metal, ruthenium is one of the major fission product elements produced with high fission yield, mainly in for breeder reactors using 239Pu fuels. In the aqueous reprocessing of spent fuels for the recovery of U and Pu by PUREX process ruthenium interferes in the solvent extraction stage. In the treatment of high level liquid waste for its disposal, oxides of Ru are formed, which contaminate the surrounding environment owing to their high vapour pressure. Hence, it is desirable to separate from the waste solution prior to its processing for disposal. A simple and feasible method has been employed in the present work for the separation and recovery of ruthenium from aqueous nitric acid medium using ammonium ceric nitrate (ACN) and carbon tetrachloride (CCl4). The efficiency in the separation of Ru was investigated under various experimental conditions such as acidity and ageing effect. Separation efficiency was observed to decrease with increasing nitric acid concentration. Maximum separation was achieved at 1 M nitric acid. Further studies were carried out to investigate the effect of ageing on the separation efficiency ruthenium. With increase in time, separation percentage of ruthenium was decreasing in all concentrations of nitric acid studied. (author)

  20. Effect of phytic acid, ethylenediaminetetraacetic acid, and chitosan solutions on microhardness of the human radicular dentin

    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

  1. Effect of phytic acid, ethylenediaminetetraacetic acid, and chitosan solutions on microhardness of the human radicular dentin

    Vineeta Nikhil

    2016-01-01

    Full Text Available 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.

  2. Corrosion Behavior of Duplex Stainless Steels in Acidic-Chloride Solutions Studied with Micrometer Resolution

    Femenia, Marc

    2003-01-01

    The local corrosion behavior of duplex stainless steel (DSS)is affected by a wide variety of factors. Localized corrosionof DSS frequently starts at micrometer scale inclusions orprecipitates, which are often segregated in theaustenite-ferrite boundary regions. Moreover, due to thepartitioning of the key alloying elements of ferrite (Cr andMo) and austenite (N and Ni), the local interactions betweenthe phases must also be considered. The aim of this doctoral study was to increase the knowledg...

  3. Investigation of corrosion and stability of lead-brass alloy in acid and neutral solutions using electrochemical impedance spectroscopy

    Badawy, W.A.; El-Egamy, S.S.; Azab, A.S. [Univ. of Cairo, Giza (Egypt). Dept. of Chemistry

    1997-11-01

    The corrosion behavior of a lead-brass alloy (58% Cu, 1.8% Pb, and 42.2% Zn) was investigated in naturally aerated acid and neutral chloride and sulfate solutions under open-circuit and potentiostatic control conditions using electrochemical impedance spectroscopy (EIS). Corrosion under open-circuit conditions was caused mainly by the dissolved oxygen depolarizer, copper (I) chloride (CuCl) or copper (I) sulfate (Cu{sub 2}SO{sub 4}), together with some surface oxides, which were assumed to be corrosion products, leading to electrode passivation. Impedance spectra in the form of Nyquist plots consisted of depressed semicircles with different degrees of depression. These depressions increased with dilution of the electrolyte rather than with immersion time. This behavior was attributed partially to inhomogeneities and surface roughness. Data were analyzed in terms of the constant phase element model, which reduced to infinite Warburg diffusion in neutral solutions. At high cathodic overpotentials, reduction of hydrogen (H{sup +}) in acid media and of oxygen in neutral media seemed to be rate controlling. Potentiostatic polarization at potentials > {minus}0.5 V led to selective dissolution of zinc and accumulation of corrosion products. At potentials > {minus}0.2 V, pitting occurred.

  4. A study of the IR spectra of the copigments of malvin chloride with organic acids

    ZORAN P. NEDIC

    2001-07-01

    Full Text Available The infrared spectra of the copigments of malvin with several organic acids: caffeic, ferulic, sinapic, chlorogenic, and tannic, were analyzed in order to elucidate the bonding of the molecules in the copigments. It was established that copigmentation is realized through hydrogen bonding between malvin molecules and the acids under study. The infrared spectra reveal that two groups of hydrogen bonds are formed, which include interactions of different molecular structures: hydroxy groups (bands around 3500 cm–1 and oxonium ions of the molecules (bands below 3000 cm–1. The formed hydrogen bonds were found to be of different strengths. The strengths of the hydrogen bonds were tentatively correlated with thermodynamic properties of the corresponding copigmentation reactions.

  5. OXIDATIVE STRESS IN SHEEP INDUCED BY CADMIUM CHLORIDE TOXICITY, WITH THERAPEUTIC EFFECTS OF ALPHA LIPOIC ACID

    Hussien Ali NAJI; Mohammad Mushgil ZENAD

    2015-01-01

    Cadmium (Cd) is a heavy toxic metal, with harmful effects on animals and public health. Recently the risk of cadmium toxicity is substantially regarded; the environmental pollution is increased due to multi- uses of this element in various industries. This study was performed to clarify the effects of acute cadmium toxicity in sheep with trail of using alpha lipoic acid as an antioxidant therapeutic substance. Fifteen male lambs aged from 5-to-7 months were divided equally in to three groups,...

  6. Adsorption of itaconic acid from aqueous solutions onto alumina

    JELENA J. GULICOVSKI

    2008-08-01

    Full Text Available Itaconic acid, IA (C5H6O4, was investigated as a potential flocculant for the aqueous processing of alumina powders. The adsorption of IA, as a function of its concentration and pH value of the solution, onto the alumina surface was studied by the solution depletion method. The stability of the suspensions in the presence of itaconic acid was evaluated in light of the surface charge of the alumina powder used, the degree of dissociation of IA, as well as the sedimentation behavior and rheology of the suspensions. It was found that the adsorption process is extremely pH dependent; the maximum adsorption of IA onto alumina surface occurring at a pH close to the value of the first IA dissociation constant, pKa1. Also, IA does not influence the value of the point of zero charge of alumina. It was shown that IA represents an efficient flocculant for concentrated acidic alumina suspensions.

  7. Role of Chloride Ion and Dissolved Oxygen in Electrochemical Corrosion of AA5083-H321 Aluminum-Magnesium Alloy in NaCl Solutions under Flow Conditions

    2007-01-01

    Flow-induced corrosion consists electrochemical and mechanical components. The present paper has to assessed the role of chloride ion and dissolved oxygen in the electrochemical component of flow induced corrosion for AA5083-H321 aluminum-magnesium alloy which is extensively used in the construction of high-speed boats, submarines, hovercrafts, and desalination systems, in NaCl solutions. Electrochemical tests were carried out at flow velocities of 0, 2, 5, 7 and 10 m/s, in aerated and deaerated NaCl solutions with different sodium chloride concentrations. The results showed that the high rate of oxygen reduction under hydrodynamic conditions causes an increase in the density of pits on the surface. The increase of chloride ions concentration under flow conditions accelerates the rate of anodic reactions, but have no influence on the cathodic reactions. Thus, in the current work, it was found that under flow conditions, due to the elimination of corrosion products inside the pits, corrosion resistance of the alloy is increased.

  8. Concentration-Purification of Uranium from an Acid Leaching Solution

    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.

  9. Transcriptome and membrane fatty acid analyses reveal different strategies for responding to permeating and non-permeating solutes in the bacterium Sphingomonas wittichii

    Johnson David R

    2011-11-01

    Full Text Available Abstract Background Sphingomonas wittichii strain RW1 can completely oxidize dibenzo-p-dioxins and dibenzofurans, which are persistent contaminants of soils and sediments. For successful application in soil bioremediation systems, strain RW1 must cope with fluctuations in water availability, or water potential. Thus far, however, little is known about the adaptive strategies used by Sphingomonas bacteria to respond to changes in water potential. To improve our understanding, strain RW1 was perturbed with either the cell-permeating solute sodium chloride or the non-permeating solute polyethylene glycol with a molecular weight of 8000 (PEG8000. These solutes are assumed to simulate the solute and matric components of the total water potential, respectively. The responses to these perturbations were then assessed and compared using a combination of growth assays, transcriptome profiling, and membrane fatty acid analyses. Results Under conditions producing a similar decrease in water potential but without effect on growth rate, there was only a limited shared response to perturbation with sodium chloride or PEG8000. This shared response included the increased expression of genes involved with trehalose and exopolysaccharide biosynthesis and the reduced expression of genes involved with flagella biosynthesis. Mostly, the responses to perturbation with sodium chloride or PEG8000 were very different. Only sodium chloride triggered the increased expression of two ECF-type RNA polymerase sigma factors and the differential expression of many genes involved with outer membrane and amino acid metabolism. In contrast, only PEG8000 triggered the increased expression of a heat shock-type RNA polymerase sigma factor along with many genes involved with protein turnover and repair. Membrane fatty acid analyses further corroborated these differences. The degree of saturation of membrane fatty acids increased after perturbation with sodium chloride but had the

  10. Carboxylic acid terminated, solution exfoliated graphite by organic acylation and its application in drug delivery

    KOUSHIK BHOWMIK; AMRITA CHAKRAVARTY; U MANJU; GOUTAM DE; ARNAB MUKHERJEE

    2016-09-01

    Graphite nanosheets are considered as a promising material for a range of applications from flexible electronics to functional nanodevices such as biosensors, intelligent coatings and drug delivery. Chemical functionalizationof graphite nanosheets with organic/inorganic materials offers an alternative approach to control the electronic properties of graphene, which is a zero band gap semiconductor in pristine form. In this paper, we report the aromatic electrophilic substitution of solution exfoliated graphite nanosheets (SEGn). The highly conjugated π-electronic system of graphite nanosheets enable it to have an amphiphilic characteristic in aromatic substitution reactions. The substitution was achieved through Friedel–Crafts (FC) acylation reaction under mild conditions using succinic anhydride as acylating agent and anhydrous aluminum chloride as Lewisacid. Such reaction renders towards the carboxylic acid terminated graphite nanosheets (SEGn–FC) that usually requires harsh reaction conditions. The product thus obtained was characterized using various spectroscopicand microscopic techniques. Highly stable water-dispersed sodium salt of carboxylic acid terminated graphite nanosheets (SEGn–FC-Na) was also prepared. A comparative sheet-resistance measurements of SEGn, SEGn–FC and SEGn–FC-Na were also done. Finally, the anticancer drug doxorubicin (DOX) was loaded on water dispersible SEGn–FC-Na with a loading capacity of 0.266 mg mg−1 of SEGn–FC-Na and the release of DOX from this water-soluble DOX-loaded SEGn–FC-Na at two different temperatures was found to be strongly pHdependent.

  11. Chloride removal from vitrification offgas

    This study identified and investigated techniques of selectively purging chlorides from the low-level waste (LLW) vitrification process with the purge stream acceptable for burial on the Hanford Site. Chlorides will be present in high concentration in several individual feeds to the LLW Vitrification Plant. The chlorides are highly volatile in combustion type melters and are readily absorbed by wet scrubbing of the melter offgas. The Tank Waste Remediation System (TWRS) process flow sheets show that the resulting chloride rich scrub solution is recycled back to the melter. The chlorides must be purged from the recycle loop to prevent the buildup of excessively high chloride concentrations

  12. Elution of zinc in dust discharged from electric arc furnace in carbonic acid solution

    The dust discharged from an electric arc furnace (EAF) is a valuable resource of zinc. As a fundamental study of extraction of zinc, iron and chlorine in the EAF dust, the elution behavior of them in carbonic acid solution was studied. The influence of the weight of the EAF dust on the elution behavior was examined in this study. Experiment was carried out putting the EAF dust from 1 g to 200 g in weight into 1 L of water that was introduced by CO2. Generally, the pH in the aqueous solution increased with an increase in weight of the additive EAF dust. Maximums of the eluted concentrations of zinc and chloride ion increased with an increase in the weight of the additive EAF dust whereas the extraction ratios of both of them decreased with an increase in the weight of the additive EAF dust. Iron in the EAF dust remained in the dust without elution. The limit of extraction of zinc from the EAF dust to water was given by the solubilities of ZnFe2O4 and ZnO expressed by eq. (6) and eq. (9) respectively.

  13. Viscosity and density of ternary solution of calcium chloride + sodium chloride + water from T = (293.15 to 323.15) K

    Qiblawey, Hazim; Arshad, Mohammad; Easa, Ahmed; Atilhan, Mert

    2014-01-01

    Viscosities and densities of ternary systems of CaCl2–NaCl–water were measured in the range of T = (293.15 to 323.15) K at 5 K intervals and up to 4.5 mol·kg–1. Two equations based on the Exponential and Goldsack and Franchetto models were applied to correlate the experimental viscosity data as a function of concentration and temperature. The optimized parameters showed that the presence of CaCl2 had a prevailing effect on the viscosity of the ternary solutions than NaCl. The dependency of th...

  14. Stress corrosion crack growth studies on nitrogen added AISI type 316 stainless steel and its weld metal in boiling acidified sodium chloride solution using the fracture mechanics approach

    Shaikh, H.; George, G.; Khatak, H.S. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Div. of Metallurgy; Schneider, F.; Mummert, K. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany). Inst. fuer Metallische Werkstoffe

    2000-10-01

    Compact tension specimens of nitrogen-added AISI type 316 austenitic stainless steel and its weld metal were subject to stress corrosion cracking (SCC) testing in a boiling solution containing 5 M sodium chloride + 0.15 M sodium sulphate + 2.5 ml/l hydrochloric acid solution using the constant extension rate testing (CERT) technique. The extension rate of testing was 10 microns per hour. The threshold values of stress intensify factor (K{sub ISCC}) and J-integral (J{sub ISCC}) were taken as those values of K{sub I} and J{sub I} at which about 25 microns of SCC crack growth was observed. These threshold values were about four times higher and plateau crack growth rates (PCGR) were nearly one order of magnitude lower for the base metal vis-a-vis the weld metal. Fractographic observations indicated failure by transgranular SCC (TGSCC) of austenite in both the base and weld metal. No stress-assisted dissolution of delta-ferrite or its interface with austenite, was observed. (orig.) [German] CT-Proben von Grund- und Schweissnahtwerkstoff des stickstoffhaltigen Stahles AISI 316 LN wurden Spannungsrisskorrosionstests in siedender chloridhaltiger Loesung (5 M Natriumchlorid/0,15 M Natriumsulfat/0,03 M Salzsaeure) unterzogen. Die Tests erfolgten bei konstanter Dehnrate (CERT-Test) von 10 {mu}m/h. Als Schwellwerte der Initiierung von Spannungsrisskorrosion K{sub ISCC} und I{sub ISCC} wurden die Werte des Spannungsintensitaetsfaktors K{sub I} und des J-Integrals J{sub I} ermittelt, bei denen ein Risswachstum von 25 {mu}m auftrat. Dabei wies der Grundwerkstoff 4-fach hoehere Schwellwerte K{sub ISCC} und J{sub ISCC} auf als der Schweissnahtwerkstoff. Auch die Risswachstumsraten im Plateaubereich der Risswachstumsrate-Spannungsintensitaetskruven waren am Grundwerkstoff um eine Groessenordnung geringer als am Schweissnahtwerkstoff. Die fraktorgrahischen Untersuchungen zeigten an beiden Materialien Schaedigung durch transkristalline Spannungsrisskorrosion. Eine

  15. The redox speciation of neptunium in acidic and alkaline solutions

    Newly developed in situ capabilities at the Advanced Photon Source have been used to obtain X-ray absorption spectroscopy (XAS) data from Np in aqueous solutions. L-edge XAS data have been obtained from acidic solutions in which Np was electrochemically stabilised in the (III) to (VI) states. A purpose-built electrochemical cell housed in appropriate safety containment allows the acquisition of XAS data while the solution is maintained under controlled applied potentials. This electrochemical cell has been used in a proof-of-concept experiment designed to demonstrate the use of X-ray absorption near-edge structural (XANES) data for the determination of thermodynamic formal potentials. XANES data were obtained at a series of applied potentials from a 1 M perchloric acid solution containing 5 mm Np. The relative concentrations of Np redox species as a function of applied potential were extracted from the data using principal component (factor) analyses. The formal potentials determined for the Np(VI)/Np(V) and Np(IV)/Np(III) couples agree with those previously published. Extended X-ray absorption fine structure (EXAFS) data were obtained from the same solution, held at potentials chosen to optimise the concentration of a single Np redox species. These data have been used to verify the co-ordination environment of Np ions as a function of oxidation state. Density functional theory (DFT), simple geometric modelling and results from the EXAFS data analysis are in agreement for the co-ordination environment of Np(III). In a related set of experiments, L-edge XAS data of Np(V), Np(VI) and Np(VII) were obtained from a basic solution. The Np oxidation state was varied by sparging the solution with ozone. Data were collected as the sample was sparged and also after the sparging gas was turned off. Np optical data were obtained in the same XAS cell and confirm the oxidation of Np(VI) to hepta-valent Np. The concentration of Np(VII) was determined using trivalent Cr as a

  16. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    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}.

  17. Adsorption of organic acids from dilute aqueous solution onto activated carbon

    The radioisotope technique was used to study the removal of organic acid contaminants from dilute aqueous solutions onto activated carbon. Acetic acid, propionic acid, n-butyric acid, n-hexanoic acid and n-heptanoic acid were studied at 278, 298, and 3130K. Three bi-solute acid mixtures (acetic and propionic acids, acetic and butanoic acids, and propionic and butanoic acids) were studied at 278 and 2980K. Isotherms of the single-solute systems were obtained at three different temperatures in the very dilute concentration region (less than 1% by weight). These data are very important in the prediction of bi-solute equilibrium data. A Polanyi-based competitive adsorption potential theory was used to predict the bi-solute equilibrium uptakes. Average errors between calculated and experimental data ranges from 4% to 14%. It was found that the competitive adsorption potential theory gives slightly better results than the ideal adsorbed solution theory

  18. Radiolytic chain oxidation of dithiothreitol in aerated acidic solutions

    In the radiolysis of dithiothreitol (DTT or HS-D-SH) in air saturated acidic and neutral solutions sulphur centered radicals are formed. In the presence of oxygen the final products are ox - DTT and H2O2 via certain complex reactions. G(ox - DTT) and G(H2O2) are dependent upon DTT and acid concentrations and dose rate. The chain is predominant only at low pH. The HO2 radical carries the chain by abstracting an H atom from DTT (k = 120 dm3mol-1s-1). The chain is continued when the DTT radicals react with oxygen to give an unstable peroxyl radical finally yielding ox - DTT and HO2. (author)

  19. Photodegradation of α-naphthaleneacetic acid in aqueous solution

    2001-01-01

    Kinetic processes of α-naphthaleneacetic acid (NAA) photolysis were studied under different conditions. The results showed that the ultraviolet light was more effective than fluorescent light in promoting degradation, and the degradation of NAA under ultraviolet light followed the first order kinetics with the photolysis rate constant of 1.15 x 10-2 min-1 and half-life time (t1/2) of 60 min. Further, it was proved that the photolysis rate was higher in the presence of oxygen, titanium dioxide (TiO2), and low pH ( acidic solution). At last, two photolysis intermediates were identified by GC-MS and possible photolysis pathways were proposed.

  20. Electrochemical Studies of Lead Telluride Behavior in Acidic Nitrate Solutions

    Rudnik E.

    2015-04-01

    Full Text Available Electrochemistry of lead telluride stationary electrode was studied in nitric acid solutions of pH 1.5-3.0. E-pH diagram for Pb-Te-H2O system was calculated. Results of cyclic voltammetry of Pb, Te and PbTe were discussed in correlation with thermodynamic predictions. Anodic dissolution of PbTe electrode at potential approx. -100÷50 mV (SCE resulted in tellurium formation, while above 300 mV TeO2 was mainly produced. The latter could dissolve to HTeO+2 under acidic electrolyte, but it was inhibited by increased pH of the bath.

  1. Selection of canister materials: electrochemical corrosion tests of HASTELLOY C4 and other Ni-Cr(-Mo) alloys in chloride containing solutions

    Several Ni-Cr(-Mo) alloys (HASTELLOY C4, INCONEL 625, SANICRO 28, INCOLOY 825, INCONEL 690) were tested by electrochemical methods to characterize their corrosion behaviour in chloride containing solutions at various temperatures and pH-values in respect to their application as canister materials for final radioactive waste storage. Especially, HASTELLOY C4 which proved to have the highest corrosion resistance of all tested alloys was tested by the following electrochemical methods: (1) Poteniodynamic measurements to determine the characteristic potentials, passive current densities and critical pitting potentials. (2) Potentiostatic measurements in order to evaluate the duration of the incubation period at various potentials. (3) Galvanostatic measurements in order to characterize critical pitting potentials. As electrolyte 1 m H2SO4 was used, as parameters temperature, chloride content and pH-value were varied. Variation of temperature gives the following results: an increase in temperature leads to an increase of the critical passivation current density, the passive potential bandwidth decreases slightly and the passive current density increases with rising temperature. The addition of different chloride contents to the H2SO4 solution shows the following effects: the critical passivation current density and the passive current density increase with increasing chloride concentration and both, the critical pitting potentials and the pitting nucleation potentials, shift towards negative values. As third parameter the pH-value was varied. As expected, an increase of the pH-value extends the passive region to more negative values, the passive current density decreases. The variation of the pH-value does not affect the critical pitting potential. All tested alloys showed a clearly limited resistance against pitting corrosion phenomena. However, the best corrosion behaviour is shown by HASTELLOY C4, which has of all tested alloys the lowest passivation current density

  2. Structure of early actinides(V) in acidic solutions

    Di Giandomenico, M.V.; Le Naour, C.; Simoni, E. [CNRS/Univ. Paris-Sud, Inst. de Physique Nucleaire, Orsay (France); Guillaumont, D.; Moisy, P.; Den Auwer, C. [CEA Marcoule, DHN/DRCP/SCPS, Bagnols sur Ceze (France); Hennig, C. [Forschungszentrum Rossendorf, Dresden (Germany); Conradson, S.D. [Los Alamos National Lab., Los Alamos, NM (United States)

    2009-07-01

    Protactinium occupies a key position in the actinide series between thorium and uranium. In aqueous acidic solution, it is stable at oxidation state (V), occurring either as an oxocation or as a naked ion, depending on the media. Very few structural information on the hydration sphere of Pa(V) in acidic medium is available, in particular in hydrofluoric acid. Combined EXAFS and theoretical calculations have been used in this work to characterize the protactinium coordination sphere at various HF concentrations. The correlation of the XAFS data with quantum chemical calculations provides complementary structural and electronic models from ab initio techniques. At HF concentrations from 0.5 to 0.05 M, both theoretical calculations and EXAFS data suggest that the protactinium coordination sphere is mainly composed of fluoride ions. At the lowest HF concentration, the occurrence of a monooxo bond is observed with EXAFS, in agreement with the literature. A comparison of these data with related neptunium(V) and plutonium(V) diooxocations in perchloric acid is also presented. (orig.)

  3. Structure of early actinides(V) in acidic solutions

    Protactinium occupies a key position in the actinide series between thorium and uranium. In aqueous acidic solution, it is stable at oxidation state (V), occurring either as an oxocation or as a naked ion, depending on the media. Very few structural information on the hydration sphere of Pa(V) in acidic medium is available, in particular in hydrofluoric acid. Combined EXAFS and theoretical calculations have been used in this work to characterize the protactinium coordination sphere at various HF concentrations. The correlation of the XAFS data with quantum chemical calculations provides complementary structural and electronic models from ab initio techniques. At HF concentrations from 0.5 to 0.05 M, both theoretical calculations and EXAFS data suggest that the protactinium coordination sphere is mainly composed of fluoride ions. At the lowest HF concentration, the occurrence of a monooxo bond is observed with EXAFS, in agreement with the literature. A comparison of these data with related neptunium(V) and plutonium(V) diooxocations in perchloric acid is also presented. (orig.)

  4. Radiolysis of capric acid in an alkaline nitrate solution

    Effect of absorbed dose of γ-radiation on radiation chemical yields of n-capric acid (CA) loss in nitrate-caustic solutions (0.52 mol/l of NaNO3, 0.24 mol/l NaOH, 0.02 mol/l Na2CO3) modelling composition of liquid radioactive wastes has been studied. Initial yield of decomposition of CA consists of 27 molecule/100 eV. Circuit of radiation-chemical degradation of CA by chain mechanism is justified. Reduction of decomposition of CA under irradiation of the solution in the presence of sandy-clay geological formation from injection well of underground waste disposal has been revealed

  5. Method of separating multi-ingredient mixed nitric acid solution

    A multi-ingredient mixed nitric acid solution as high level liquid wastes is heated to a temperature higher than the denitrification temperature at which transuranium elements are converted from the form of nitrate compounds to oxides, and then water is added. The transuranium elements are converted into water insoluble oxides. On the contrary, since nuclides of fission products having extremely high denitrification temperatures are left in the form of nitrates as they are even after the heating and they are dissolved in water, only the transuranium elements can be easily separated. The solution selectively separated and removed only with the transuranium elements having long half decay times are vitrified by a usual method. Accordingly, the storage period of the vitrification products is extremely shortened, to improve the processing safety. (T.M.)

  6. Radiation chemistry of amino acids and peptides in aqueous solutions

    Radiation chemistry relevant to radiation preservation of high protein foods is reviewed. Some conclusions concerning the chemistry of irradiated amino acids, peptides, and proteins have been derived from product analysis of γ-irradiated solutions while the main mechanistic considerations result from the chemistry and kinetics of free radical intermediates observed by pulse radiolysis. The precursors of chemistry in not too concentrated solutions (-, OH, and H. Their reactivity with molecules and their preference for characteristic groups within the molecule are discussed. The reviewed reactions of the model systems are accountable for a variety of radiolytic products found in irradiated foods. From detailed understanding of radiation chemistry in aqueous and frozen systems formation of many classes of compounds can be predicted or entirely eliminated in order to corroborate and extend the conclusions reached from the animal feeding experiments concerning the formation of toxic, mutagenic, and carcinogenic compounds and/or reduction of the nutritional value of foods

  7. Oxydesulfurization of coal by acidic iron sulfate solutions

    Mixon, D.A.; Vermeulen, T.

    1981-08-01

    To facilitate by-product recovery and eliminate elemental sulfur formation in coal oxydesulfurization, high-sulfur bituminous coal has been treated with aqueous ferric sulfate/sulfuric acid and oxygen at 100 to 150/sup 0/C. The rate of pyrite oxidation increases with oxygen partial pressure, temperature, and fineness of grinding. This reaction rate is relatively insensitive to sulfuric acid and ferric sulfate concentrations, so that pyrite removal may be satisfactorily performed in solutions containing 25% H/sub 2/SO/sub 4/ and 12% Fe/sub 2/(SO/sub 4/)/sub 3/ (weight percentages relative to total H/sub 2/O plus H/sub 2/SO/sub 4/); preliminary data suggest that such a leaching solution is only mildly corrosive to T316 stainless steel, at 150/sup 0/C or below, in the presence of oxygen. To provide an accurate assessment of coal oxydesulfurization stoichiometry, an analytical technique based on uv spectrophotometry has been developed for the determination of elemental sulfur in coal. Prepared coal samples are extracted for 24 hours with cyclohexane. Other exploratory oxydesulfurization runs have shown that vanadium oxides are not effective catalysts at 100/sup 0/C, with oxygen. Nor are lauryl sulfate or sulfates of zinc, copper, or manganese effective additives in the ferric sulfate/sulfuric acid/oxygen system at 150/sup 0/C. Elemental chlorine has been shown to be capable of removing significant amounts of organic sulfur from coal, at 74/sup 0/C, but suffers the drawback of chlorinating the coal's orgaic matrix. Hydrogen peroxide in aqueous sulfuric acid is an effective reagent for pyrite removal at 100/sup 0/C, but is unduly expensive.

  8. Synthesis of nesquehonite by reaction of gaseous CO2 with Mg chloride solution: its potential role in the sequestration of carbon dioxide.

    Ferrini, Vincenzo; De Vito, Caterina; Mignardi, Silvano

    2009-09-15

    In this paper is reported a novel method to synthesize nesquehonite, MgCO(3) x 3H(2)O, via reaction of a flux of CO(2) with Mg chloride solution at 20+/-2 degrees C. The reaction rate is rapid, with carbonate deposition almost complete in about 10 min. The full characterization of the product of synthesis has been performed to investigate its potential role as a "CO(2)-sequestering medium" and a means of disposing Mg-rich wastewater. We investigated the nesquehonite synthesized using SEM, XRD, FTIR and thermal analysis. The thermodynamic and chemical stability of this low-temperature hydrated carbonate of Mg and its possible transformation products make our method a promising complementary solution to other methods of CO(2) sequestration. Carbonation via magnesium chloride aqueous solutions at standard conditions represents a simple and permanent method of trapping CO(2). It could be applied at point sources of CO(2) emission and could involve rejected brine from desalination plants and other saline aqueous wastes (i.e., "produced water"). The likelihood of using the resulting nesquehonite and the by-products of the process in a large number of applications makes our method an even more attractive solution. PMID:19303209

  9. Synthesis of nesquehonite by reaction of gaseous CO{sub 2} with Mg chloride solution: Its potential role in the sequestration of carbon dioxide

    Ferrini, Vincenzo; De Vito, Caterina [Dipartimento di Scienze della Terra, Universita degli Studi di Roma ' La Sapienza' , P.le A. Moro, 5, 00185 Roma (Italy); Mignardi, Silvano, E-mail: silvano.mignardi@uniroma1.it [Dipartimento di Scienze della Terra, Universita degli Studi di Roma ' La Sapienza' , P.le A. Moro, 5, 00185 Roma (Italy)

    2009-09-15

    In this paper is reported a novel method to synthesize nesquehonite, MgCO{sub 3}.3H{sub 2}O, via reaction of a flux of CO{sub 2} with Mg chloride solution at 20 {+-} 2 deg. C. The reaction rate is rapid, with carbonate deposition almost complete in about 10 min. The full characterization of the product of synthesis has been performed to investigate its potential role as a 'CO{sub 2}-sequestering medium' and a means of disposing Mg-rich wastewater. We investigated the nesquehonite synthesized using SEM, XRD, FTIR and thermal analysis. The thermodynamic and chemical stability of this low-temperature hydrated carbonate of Mg and its possible transformation products make our method a promising complementary solution to other methods of CO{sub 2} sequestration. Carbonation via magnesium chloride aqueous solutions at standard conditions represents a simple and permanent method of trapping CO{sub 2}. It could be applied at point sources of CO{sub 2} emission and could involve rejected brine from desalination plants and other saline aqueous wastes (i.e., 'produced water'). The likelihood of using the resulting nesquehonite and the by-products of the process in a large number of applications makes our method an even more attractive solution.

  10. Temperature Induced Aggregation and Clouding in Humic Acid Solutions

    Leah Shaffer

    2015-01-01

    Full Text Available Humic acids in aqueous solution demonstrate inverse temperature-solubility relationships when solution conditions are manipulated to reduce coulombic repulsion among the humic polyanions. These effects were followed by dynamic light scattering (DLS measurements of the resulting aggregates, as well as the addition of a polarity sensitive fluorescent probe (pyrene. The humic solutions could be primed for temperature induced clouding by carefully lowering the pH to a point where hydration effects became dominant. The exact value of the cloud point (CP was a function of both pH and humate concentration. The CPs mostly lay in the range 50–90°C, but DLS showed that temperature induced aggregation proceeded from approximately 30°C onward. Similar effects could be achieved by adding multivalent cations at concentrations below those which cause spontaneous precipitation. The declouding of clouded humate solutions could be affected by lowering the temperature combined with mechanical agitation to disentangle the humic polymers.

  11. OXIDATIVE STRESS IN SHEEP INDUCED BY CADMIUM CHLORIDE TOXICITY, WITH THERAPEUTIC EFFECTS OF ALPHA LIPOIC ACID

    Hussien Ali NAJI

    2015-09-01

    Full Text Available Cadmium (Cd is a heavy toxic metal, with harmful effects on animals and public health. Recently the risk of cadmium toxicity is substantially regarded; the environmental pollution is increased due to multi- uses of this element in various industries. This study was performed to clarify the effects of acute cadmium toxicity in sheep with trail of using alpha lipoic acid as an antioxidant therapeutic substance. Fifteen male lambs aged from 5-to-7 months were divided equally in to three groups, they were supplied with ordinary diet and provided with water ad-lib, the first group 1 was administered a single dose of CdCl2 3 mg/kg.bw subcutaneously (S/C, the second group 2 was injected with the same dose of CdCl2 and by the same route, and then simultaneously administered an alpha lipoic acid 50 mg/kg.bw intramuscularly, the later drug was repeated after 12 hours via the same route. The third group 3 was left as control and given normal saline (S/C. All animals were daily monitored and the clinical signs were recorded. The signs of cadmium toxicity appeared 18 hours post CdCl2 administration in the group 1; the signs were gradually increased in severity and multiple systems were involved included: digestive disturbances, cardiovascular and neurological dysfunctions, and locomotors abnormalities. Significant elevations in the body temperature, respiratory and heart rates were observed, deaths of 2 lambs were recorded 96 hours post CdCl2 injection. The group 2 showed mild clinical signs, and no death was occurred, moreover insignificant variations between clinical parameters in both groups 2 and 3 were recorded. Serum biochemical analysis revealed significant (P<0.05 increased of malondialdehyde (5.41 ± 0.282 μmol/L and glutathione (10.68 ± 0.38 μmol/L concentrations and marked elevation of serum catalase activity (103.85 ± 3.93 u/L was also observed in group I, whereas the last three parameters showed no significant differences between groups 2

  12. Corrosion resistance of flaky aluminum pigment coated with cerium oxides/hydroxides in chloride and acidic electrolytes

    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.

  13. Anodic behavior of Mg in acidic AlCl3–1-ethyl-3-methyl-imidazolium chloride ionic liquid

    Highlights: • A viscous layer formed at Mg/ionic liquid interface after the dissolution of Mg. • As direct evidence, photo of viscous layer at the interface was presented. • Viscous layer was resulted from accumulation of dissolved Mg(II) at interface. • Formation of viscous layer resulted in a homogenous etched Mg surface. • Dissolution model of Mg and formation mechanism of viscous layer was discussed. - Abstract: In this paper, anodic behavior of Mg in acidic AlCl3–1-ethyl-3-methyl-imidazolium chloride (AlCl3–EMIC) ionic liquid was investigated by conducting linear sweep voltammetry, chronoamperometry and chonopotentiometry. The viscosity of Mg dissolved ionic liquid and the surface morphologies of Mg were characterized using an Ostwald viscometer and a scanning electron microscopy, respectively. The results showed that the oxide film on the surface of Mg had great effects on the anodic behavior. The dissolution of Mg under anodic polarization occurred after the breakdown of oxide film. A viscous layer was observed forming at the interface of Mg/ionic liquid during the dissolution process. The formation of viscous layer was attributed to the accumulation of Mg dissolved AlCl3–EMIC ionic liquid at the interface, which was of high viscosity. With a viscous layer formed in the anodic process, the etched surface of Mg anode was homogeneous and flat without any etching pits. Otherwise, the Mg showed a morphology of pitting on the surface

  14. Arsenic removal from acidic solutions with biogenic ferric precipitates.

    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

  15. Thick pure palladium film with varied crystal structure electroless deposited from choline chloride–palladium chloride solution without the addition of reductant

    Immersion deposition procedure was applied to achieve thick pure palladium films with thickness up to about 3 μm from choline chloride (ChCl)–palladium chloride (PdCl2) aqueous solution without addition of reductant at 60 °C. Using X-ray diffraction and scanning electron microscope, it was confirmed that Pd films with different crystal orientations and morphology were obtained just by varying the immersion time, and Pd (111) crystal orientation predominated over other crystal orientations during the initial deposition procedure, while (220) conquered (111) about 45 min later. ChCl performing as a reductant facilitated the growth of thick Pd film free of reductant. The immersion deposition of Pd followed the mechanism of replacement reaction accompanying with autocatalyzed reaction and autocatalyzed reaction predominating over replacement reaction. The results revealed that Pd films prepared from ChCl–PdCl2 solution had excellent properties on solderability and corrosion resistance. - Highlights: • Thick pure Pd film was obtained from ChCl–PdCl2 aqueous solution without reductant. • Different crystal orientations and morphology of Pd films were achieved. • Immersion time determined the morphology of Pd films. • The mechanism of sustained deposition of Pd on Ni–P surface was deduced

  16. Thick pure palladium film with varied crystal structure electroless deposited from choline chloride–palladium chloride solution without the addition of reductant

    Wang, Yurong; Li, Wei; Wang, Wenchang [School of Petrochemical Engineering, Key Laboratory of Fine Petrochemicals of Jiangsu Province, Changzhou University, Changzhou 213164 (China); Mitsuzak, Naotoshi [Qualtec Co., Ltd, Osaka 590-0906 (Japan); Bao, Weiliang [Department of Chemistry, Zhejiang University, Hanghzou 310058 (China); Chen, Zhidong, E-mail: chen13775646759@hotmail.com [School of Petrochemical Engineering, Key Laboratory of Fine Petrochemicals of Jiangsu Province, Changzhou University, Changzhou 213164 (China); School of Material Science and Engineering, Jiangsu Key Laboratory of Material Surface Technology, Changzhou University, Changzhou 213164 (China)

    2015-07-01

    Immersion deposition procedure was applied to achieve thick pure palladium films with thickness up to about 3 μm from choline chloride (ChCl)–palladium chloride (PdCl{sub 2}) aqueous solution without addition of reductant at 60 °C. Using X-ray diffraction and scanning electron microscope, it was confirmed that Pd films with different crystal orientations and morphology were obtained just by varying the immersion time, and Pd (111) crystal orientation predominated over other crystal orientations during the initial deposition procedure, while (220) conquered (111) about 45 min later. ChCl performing as a reductant facilitated the growth of thick Pd film free of reductant. The immersion deposition of Pd followed the mechanism of replacement reaction accompanying with autocatalyzed reaction and autocatalyzed reaction predominating over replacement reaction. The results revealed that Pd films prepared from ChCl–PdCl{sub 2} solution had excellent properties on solderability and corrosion resistance. - Highlights: • Thick pure Pd film was obtained from ChCl–PdCl{sub 2} aqueous solution without reductant. • Different crystal orientations and morphology of Pd films were achieved. • Immersion time determined the morphology of Pd films. • The mechanism of sustained deposition of Pd on Ni–P surface was deduced.

  17. Reversibility of soil solution acidity and of sulfate retention in acid forest soils

    Alewell, C.; Matzner, E. (Universitaet Bayreuth, Bayreuth (Germany). Lehrstuhl fuer Bodenoekologie)

    1993-11-01

    To quantify the effects of reduced sulfate input on the chemistry of soil solution and soil S storage in acid forest soils, an experiment with undisturbed soil columns from two different sites was implemented. The acid cambisol of the Solling is subjected to a high sulfate input and especially the B-horizon has a high sulfate content. On the contrary, the podzol of the Fuhrberg site is subjected to low input and has low sulfate content. Undisturbed soil columns were taken from both sites and were irrigated at 6[degree]C with a precipitation rate of 3 mmd[sup -1] over 10 mo. In treatment No. 1, an artificial throughfall with pH 5.2 and reduced sulfate load (45[mu]mol L[sup -1]) was applied. In treatment No. 2, an artificial throughfall representing a high sulfate deposition (427 [mu]mol L[sup -1], pH 3.2) was used. In the case of the Solling soil, the pH of soil solution was unaffected by treatments during the entire experiment. Alkalinity of the soil solution was slightly increased in treatment No. 1 at a depth of 20 cm. While treatment No. 1 resulted in a reduction of the sulfate concentrations of the soil solution in the top soil, sulfate concentrations were unaffected at a depth of 40 cm. The B-horizon of the Solling soil prevented deacidification of the soil solution by desorption of previously stored sulfate. In the case of the Fuhrberg soil, treatment No. 1 resulted in reduced sulfate concentrations of the soil solution even in deeper soil layers with concentrations approaching input levels. The pH of the solution was slightly elevated and the alkalinity of the solution increased. Organic S compounds in the soil seemed to have no influence on sulfate release in either soils. 37 refs., 3 figs., 1 tab.

  18. Precipitation of plutonium from acidic solutions using magnesium oxide

    Plutonium (IV) is only marginally soluble in alkaline solution. Precipitation of plutonium using sodium or potassium hydroxide to neutralize acidic solutions produces a gelatinous solid that is difficult to filter and an endpoint that is difficult to control. If the pH of the solution is too high, additional species precipitate producing an increased volume of solids separated. The use of magnesium oxide as a reagent has advantages. It is added as a solid (volume of liquid waste produced is minimized), the pH is self-limiting (pH does not exceed about 8.5), and the solids precipitated are more granular (larger particle size) than those produced using KOH or NaOH. Following precipitation, the raffinate is expected to meet criteria for disposal to tank farms. The solid will be heated in a furnace to dry it and convert any hydroxide salts to the oxide form. The material will be cooled in a desiccator. The material is expected to meet vault storage criteria

  19. Changes in humic acid conformation during coagulation with ferric chloride: implications for drinking water treatment.

    Siéliéchi, J-M; Lartiges, B S; Kayem, G J; Hupont, S; Frochot, C; Thieme, J; Ghanbaja, J; d'Espinose de la Caillerie, J B; Barrès, O; Kamga, R; Levitz, P; Michot, L J

    2008-04-01

    Electrophoretic mobility, pyrene fluorescence, surface tension measurements, transmission electron microscopy on resin-embedded samples, and X-ray microscopy (XRM) were combined to characterize the aggregates formed from humic colloids and hydrolyzed-Fe species under various conditions of pH and mixing. We show that, at low coagulant concentration, the anionic humic network is reorganized upon association with cationic coagulant species to yield more compact structures. In particular, spheroids about 80nm in size are evidenced by XRM at pH 6 and 8 just below the optimal coagulant concentration. Such reorganization of humic colloids does not yield surface-active species, and maintains negative functional groups on the outside of humic/hydrolyzed-Fe complex. We also observe that the humic network remains unaffected by the association with coagulant species up to the restabilization concentration. Upon increasing the coagulant concentration, restructuration becomes limited: indeed, the aggregation of humic acid with hydrolyzed-Fe species can be ascribed to a competition between humic network reconformation rate and collision rate of destabilized colloids. A decrease in stirring favors the shrinkage of humic/hydrolyzed-Fe complexes, which then yields a lower sediment volume. Elemental analyses also reveal that the iron coagulant species are poorly hydrolyzed in the destabilization range. This suggests that destabilization mechanisms such as sweep flocculation or adsorption onto a hydroxyde precipitate are not relevant to our case. A neutralization/complexation destabilization mechanism accompanied by a restructuration of flexible humic network is then proposed to occur in the range of pHs investigated. PMID:18155268

  20. Phenomenon of magnetic birefringence in solutions of paramagnetic substances. Communication 2. Molar-magneto-optic constants of chlorides and nitrates of some lanthanides in water

    This paper determines the molar constants of the magnetic birefringence of chlorides and nitrates of some lanthanides in water and extrapolates them to infinite dilution. The principal semiaxes of the optical-polarizability ellipsoids of hydrated rare-earth cations have been evaluated in the axial approximation. The magneto-optic properties of dilute solutions of lanthanide nitrates (Ln = Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er) are attributed to the constancy of the composition and structure of the aquo complexes with the participation of nitrate anions

  1. Correlation between the Increasing Conductivity of Aqueous Solutions of Cation Chlorides with Time and the “Salting-Out” Properties of the Cations

    Nada Verdel

    2016-02-01

    Full Text Available The time-dependent role of cations was investigated by ageing four different aqueous solutions of cation chlorides. A linear correlation was found between the cations’ Setchenov coefficient for the salting-out of benzene and the increase in the conductivity with time. The conductivity of the structure-breaking cations or the chaotropes increased more significantly with time than the conductivity of the kosmotropes. Since larger water clusters accelerate the proton or hydroxyl hopping mechanism, we propose that the structuring of the hydration shells of the chaotropes might be spontaneously enhanced over time.

  2. The environment-induced cracking of as-annealed Ni3(Si,Ti) and Ni3(Si,Ti) with 2Mo in sodium chloride solutions

    Priyotomo, Gadang; Wagle, Sanat; Okitsu, Kenji; Iwase, Akihiro; Kaneno, Yasuyuki; Nishimura, Rokuro; Takasugi, Takayuki

    2015-01-01

    Background The environment-induced cracking (EIC) of as-annealed Ni3(Si,Ti) and Ni3(Si,Ti) with 2Mo has been researched as functions of applied stress, chloride ion concentration, test temperature, and pH. Methods The investigation of EIC was carried out by applying a constant method in NaCl solutions. Results The EIC susceptibility of both intermetallic compounds increased with increasing test temperature and Cl− ion concentration and increased with decreasing pH. The fra...

  3. Dissolution of metal oxides in an acid-saturated ionic liquid solution and investigation of the back-extraction behaviour to the aqueous phase

    Wellens, Sil; Vander Hoogerstraete, Tom; Möller, Claudia; Thijs, Ben; Luyten, Jan; Binnemans, Koen

    2014-01-01

    The dissolution of metal oxides in an acid-saturated ionic liquid, followed by selective stripping of the dissolved metal ions to an aqueous phase is proposed as a new ionometallurgical approach for the processing of metals in ionic liquids. The hydrophobic ionic liquid trihexyl(tetradecyl)phosphonium chloride (Cyphos IL 101) saturated with a concentrated aqueous hydrochloric acid solution was used to dissolve CaO, NiO, MnO, CoO, CuO, ZnO and Fe2O3. It was found that nickel(II) and calcium...

  4. INTERACTION OF AQUEOUS SOLUTIONS OF CHLORINE WITH MALIC ACID, TARTARIC ACID, AND VARIOUS FRUIT JUICES, A SOURCE OF MUTAGENS

    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...

  5. Separation of 230Th (ionium) from uranium ores sulfuric acid and in nitric acid solutions

    230Th (ionium) is of interest for production of 231Pa, the Pa isotope with the longest half life, and for production of 232U which can be used in radionuclide batteries. Two procedures are presented which have been worked out for separation of 230Th from sulfuric acid and from nitric acid solutions. In the first case the effluents from the anion exchange resins are the starting material for recorvery of 230Th, in the second case the cation exchange resins which are for purification of U. The procedures selected are simple, economic and can be performed in any uranium mill or uranium purification plant without additional investments. (orig.)

  6. Solution behavior of iron(III-N,N'-ethylene-bis-(salicylideneiminato-chloride in aqueous methanol at 298.15, 303.15 and 313.15K

    Brahman Dhiraj

    2014-01-01

    Full Text Available In this study partial molar volumes (φV0 and viscosity B-coefficients of iron(III-N, N'-ethylene-bis(salicylideneiminato-chloride, abbreviated as FeIII(salenCl, in different aqueous methanol solutions were determined from solution density and viscosity measurements at temperatures 298.15, 303.15, and 313.15 K under ambient pressure. Apparent molar volumes (φV and densities (ρ were used to calculate the apparent molar expansibilities (φE, the partial molar expansibilities (φE0 and the temperature dependence of the partial molar expansibilities (φE0 at constant pressure, (δφE0/δTP of FeIII(salenCl solutions to reveal the nature of different interactions in the ternary solutions. The transition state theory was applied to analyze the viscosity B-coefficients on the basis of the activation parameters of viscous flow. The overall results indicated strong solute-solvent interactions between FeIII(salenCl and the solvent molecules, preferentially with water molecules and that FeIII(salenCl acts as a net structure promoter in the ternary solutions. UV-VIS absorption spectra of the ternary solutions also stand in support of the results obtained.

  7. Rheological behaviour of some saccharides in aqueous potassium chloride solutions over temperature range (288.15 to 318.15) K

    Banipal, Parampaul K., E-mail: pkbanipal@yahoo.co [Department of Chemistry, Guru Nanak Dev University, Amritsar 143005 (India); Chahal, Amanpreet K.; Singh, Vickramjeet [Department of Chemistry, Guru Nanak Dev University, Amritsar 143005 (India); Banipal, Tarlok S. [Department of Applied Chemistry, Guru Nanak Dev University, Amritsar 143005 (India)

    2010-08-15

    The viscosities, {eta} of mono-, di-, tri-saccharides and methylglycosides, viz., D(+)-xylose (XYL), D(-)-arabinose (ARA), D(-)-ribose (RIB), D(-)-fructose (FRU), D(+)-galactose (GAL), D(+)-mannose (MAN), D(+)-glucose (GLU), D(+)-melibiose (MEL), D(+)-cellobiose (CEL), D(+)-lactose monohydrate (LAC), D(+)-maltose monohydrate (MAL), D(+)-trehalose dihydrate (TRE), sucrose (SUC), D(+)-raffinose pentahydrate (RAF), {alpha}-methyl-D(+)-glucoside ({alpha}-Me-GLU), methyl-{alpha}-D-xylopyranoside (Me-{alpha}-XYL), and methyl-{beta}-D-xylopyranoside (Me-{beta}-XYL) in water and in (0.5, 1.0, 2.0, and 3.0) mol . kg{sup -1} aqueous solutions of potassium chloride (KCl) have been determined at T = (288.15, 298.15, 308.15, and 318.15) K from efflux time measurements by using a capillary viscometer. Densities used to determine viscosities have been reported earlier. The viscosity data have been utilized to determine the viscosity B-coefficients employing the Jones-Dole equation at different temperatures. From these data, the viscosity B-coefficients of transfer, {Delta}{sub t}B have been estimated for the transfer of various saccharides/methylglycosides from water to aqueous potassium chloride solutions. The {Delta}{sub t}B values have been found to be positive, whose magnitude increases with the increase in concentration of potassium chloride in all cases. The dB/dT coefficients, pair, {eta}{sub AB} and triplet, {eta}{sub ABB} viscometric interaction coefficients have also been determined. Gibbs free energies of activation and related thermodynamic parameters of activation of viscous flow have been determined employing Feakin's transition-state theory. The signs and magnitudes of various parameters have been discussed in terms of solute-solute and solute-solvent interactions occurring in these solutions. The effect of substitution of -OH by methoxy group, -OCH{sub 3} has also been discussed.

  8. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    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

  9. Optical properties of chitosan in aqueous solution of L- and D-ascorbic acids

    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.

  10. Thermophysical property characterization of aqueous amino acid salt solutions containing α-aminobutyric acid

    Highlights: • Thermophysical properties of aqueous potassium and sodium salt solutions of α-aminobutyric acid were studied. • Density, electrolytic conductivity, refractive index, and viscosity of the solution were measured. • The concentrations of amino acid salt ranges from x1 = 0.009 to 0.06. • The temperature range studied was (303.15 to 343.15) K. • The measured data were represented satisfactorily by using the applied correlations. - Abstract: In this study, density, electrical conductivity, refractive index and viscosity of aqueous potassium and sodium salt solutions of α-aminobutyric acid were presented. Measurements were done over the temperature range (303.15 to 343.15) K and atmospheric pressure for salt compositions from x1 = 0.009 to 0.062. A modified Graber et al. equation was used to correlate the density, electrical conductivity, and refractive index with temperature and composition leading to average absolute deviations (AAD) between the predicted and calculated values of 0.04%, 0.7%, and 0.01%, respectively. The viscosity data were represented as a function of temperature and composition via Vogel–Tamman–Fulcher (VTF) type equation at an AAD of 0.6%

  11. Optimization of Preparation of Activated Carbon from Ricinus communis Leaves by Microwave-Assisted Zinc Chloride Chemical Activation: Competitive Adsorption of Ni2+ Ions from Aqueous Solution

    M. Makeswari

    2013-01-01

    Full Text Available The preparation of activated carbon (AC from Ricinus communis leaves was investigated in this paper. Orthogonal array experimental design method was used to optimize the preparation of AC using microwave assisted zinc chloride. Optimized parameters were radiation power of 100 W, radiation time of 8 min, concentration of zinc chloride of 30% by volume, and impregnation time of 24 h, respectively. The surface characteristics of the AC prepared under optimized conditions were examined by pHZPC, SEM-EDAX, XRD, and FTIR. Competitive adsorption of Ni2+ ions on Ricinus communis leaves by microwave assisted zinc chloride chemical activation (ZLRC present in binary and ternary mixture was compared with the single metal solution. The effects of the presence of one metal ion on the adsorption of the other metal ion were investigated. The experimental results indicated that the uptake capacity of one metal ion was reduced by the presence of the other metal ion. The extent of adsorption capacity of the binary and ternary metal ions tested on ZLRC was low (48–69% as compared to single metal ions. Comparisons with the biosorption of Ni2+ ions by the biomass of ZLRC in the binary (48.98–68.41%-~Ni-Cu and 69.76–66.29%-~Ni-Cr and ternary solution (67.32–57.07%-~Ni–Cu and Cr could lead to the conclusion that biosorption of Ni2+ ions was reduced by the influence of Cu2+ and Cr3+ ions. The equilibrium data of the adsorption was well fitted to the Langmuir isotherm. The adsorption process follows the pseudo-second-order kinetic model.

  12. Deprotonation of salicylic acid and 5-nitrosalicylic acid in aqueous solutions of ethanol

    Faraji Mohammad

    2011-01-01

    Full Text Available The protonation constant values of two hydroxybenzoic acids (salicylic and 5-nitrosalicylic acid were studied in some water-ethanol solutions using spectrophotometric and potentiometric methods at 25°C and in an ionic strength of 0.1 M sodium perchlorate. The results indicated that the pKa values increase with increasing proportion of ethanol in mixed solvent. The dependence of the protonation constants on the variation of the solvent were correlated by the dielectric constants of the media. Furthermore, for a better understanding of the solvent influence, the obtained results were explained in terms of the Kamlet-Taft parameters α (hydrogen-bond donor acidity, π

  13. Study of the Dissolution of Chalcopyrite in Sulfuric Acid Solutions Containing Alcohols and Organic Acids

    Chalcopyrite dissolution under environmental conditions has been one of the major challenges facing researchers. The current processes for obtaining copper have pollution issues, which will severely limit their application as environmental controls become stricter. Faced with this problem, a number of eco-friendlier methods, such as GALVANOX and HydroCopper (Outokumpu), have been proposed, although they have not been industrialized, mainly due to their high operating costs. The authors previously proposed an alternative system to leach chalcopyrite, which is based on the use of aqueous polar organic solutions. In the process, copper extraction increases in mixtures of acetone or ethylene glycol with aqueous sulfuric acid solutions. The drawback is the large concentration of oxidizing agents needed to obtain high percentages of chalcopyrite dissolution, which can make the process lose viability. In this investigation, the effect of acetic acid, formic acid, methanol and ethanol, whose chemical characteristics are similar to those previously proposed, were evaluated by cyclic voltammetry. It was found that, in the presence of these organic solvents, higher electrochemical responses were obtained compared with those found with sulfuric acid alone, a similar behavior to that obtained with acetone. Leaching experiments results coincided with the corresponding findings of the electrochemical study and X-ray diffraction results provided evidence to support the proposed reactions

  14. Henry’s constants and activity coefficients of some organic solutes in 1-butyl,3-methylimidazolium hydrogen sulfate and in 1-methyl,3-trimethylsilylmethylimidazolium chloride

    Highlights: ► New solubility data are reported for two ionic liquids. ► Density data are reported. ► Thermo-gravimetric analysis data are obtained. - Abstract: Using a customized capillary gas–liquid chromatography column, Henry’s constants and activity coefficients at infinite dilution are reported for benzene, toluene, ethyl acetate, 1,4-dioxane, 1,2-dimethoxyethane, acetonitrile, nitromethane, tetrahydrofuran, chloroform, methanol, ethanol, and 1-propanol in ionic liquids 1-butyl,3-methylimidazolium hydrogen sulfate [BMIM][HSO4] and 1-methyl,3-trimethylsilylmethylimidazolium [SiMIM][Cl] chloride from 313 to 413 K. These acidic ionic liquids may provide suitable media for acid-catalyzed chemical reactions.

  15. Preparation of a chitosan-based anionic exchanger for removal of bromide, chloride, iodide and phosphate ions from aqueous solutions

    Affonso Celso Gonçalves Júnior

    2014-02-01

    Full Text Available The development of a chitosan anion exchanger, obtained from shrimp shells, and its adsorption capacity for chloride, bromide, iodide and phosphate anions are provided. Dependence of exchange processes with the anions as a function of pH and contact time between exchanger and anions were initially investigated. Results showed that the best adsorption of ions occurred at pH 3.0. Exchange isotherms were then developed by the Langmuir, Freundlich and Dubinin-Radushkevich mathematical models. Results demonstrated that chitosan produced from shrimp shells may be used as feedstock in the manufacture of anion exchange microspheres.

  16. ADSORPTION FROM AQUEOUS SOLUTION ONTO NATURAL AND ACID ACTIVATED BENTONITE

    Laila Al-Khatib

    2012-01-01

    Full Text Available Dyes have long been used in dyeing, paper and pulp, textiles, plastics, leather, paint, cosmetics and food industries. Nowadays, more than 100,000 commercial dyes are available with a total production of 700,000 tones manufactured all over the world annually. About 10-15% of dyes are being disposed off as a waste into the environment after dyeing process. This poses certain hazards and environmental problems. The objective of this study is to investigate the adsorption behavior of Methylene Blue (MB from aqueous solution onto natural and acid activated Jordanian bentonite. Both bentonites are firstly characterized using XRD, FTIR and SEM techniques. Then batch adsorption experiments were conducted to investigate the effect of initial MB concentration, contact time, pH and temperature. It was found that the percentage of dye removal was improved from 75.8% for natural bentonite to reach 99.6% for acid treated bentonite. The rate of MB removal followed the pseudo second order model with a high correlation factor. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. The Langmuir isotherm model was found more representative. The results indicate that bentonite could be employed as a low cost adsorbent in wastewater treatment for the removal of colour and dyes.

  17. Influence of salicylic acid on rubisco and rubisco activase in tobacco plant grown under sodium chloride in vitro.

    Lee, So Young; Damodaran, Puthanveettil Narayanankutty; Roh, Kwang Soo

    2014-11-01

    The present study was designed to evaluate the influence of salicylic acid (SA) on the growth of salt stress (sodium chloride) induced in tobacco plants. In addition, quantification of rubisco and rubisco activase contents of the plants was also determined in treatments with the control, 10(-4) mM SA, 50 mM NaCl, 100 mM NaCl, 150 mM NaCl, SA + 50 mM NaCl, SA + 100 mM NaCl and SA + 150 mM NaCl, respectively after in vitro culture for 5 weeks. The growth of the tobacco plant decreased in 50 mM and 100 mM NaCl when not treated with SA. However, the growth was accelerated by SA, and the growth retardation caused by NaCl was improved by SA. The content of rubisco was improved by SA only in plants treated with 50 mM NaCl, and the activity of rubisco was increased by SA resulting in the decreased effect of NaCl, but only in 50 mM NaCl treated plants. The content of rubisco activase decreased due to NaCl, and SA did not improve the effect caused by NaCl. The activity of rubisco activase was increased by SA resulting in decreased activity caused by NaCl, but increased effect by SA was not recovered to the level of NaCl untreated plants. The activity of rubisco and rubisco activase, which decreased due to denaturing agents, did not demonstrate significant improvement when compared to the control. PMID:25313276

  18. Synthesis, magnetic and spectral studies of lanthanide(III) chloride complexes of hydrazones of isonicotinic acid hydrazide

    The synthesis, magnetic and spectral properties of trivalent lanthanide chlorides with N-isonicotinamidobenzalaldimine (INH-BENZ), N-isonicotinamidoanisalaldimine (INH-ANSL) and N-isonicotinamido-p-dimethylaminobenzalaldimine (INH-PDAB) are described. 13 refs., 2 tabs

  19. Chloride-inducible transient apoplastic alkalinizations induce stomata closure by controlling abscisic acid distribution between leaf apoplast and guard cells in salt-stressed Vicia faba.

    Geilfus, Christoph-Martin; Mithöfer, Axel; Ludwig-Müller, Jutta; Zörb, Christian; Muehling, Karl H

    2015-11-01

    Chloride stress causes the leaf apoplast transiently to alkalize, an event that is presumed to contribute to the ability of plants to adapt to saline conditions. However, the initiation of coordinated processes downstream of the alkalinization is unknown. We hypothesize that chloride-inducible pH dynamics are a key chemical feature modulating the compartmental distribution of abscisic acid (ABA) and, as a consequence, affecting stomata aperture. Apoplastic pH and stomata aperture dynamics in intact Vicia faba leaves were monitored by microscopy-based ratio imaging and porometric measurements of stomatal conductance. ABA concentrations in leaf apoplast and guard cells were compared with pH dynamics by gas-chromatography-mass-spectrometry (GC-MS) and liquid-chromatography-tandem-mass spectrometry (LC-MS/MS). Results demonstrate that, upon chloride addition to roots, an alkalizing factor that initiates the pH dynamic propagates from root to leaf in a way similar to xylem-distributed water. In leaves, it induces a systemic transient apoplastic alkalinization that causes apoplastic ABA concentration to increase, followed by an elevation of endogenous guard cell ABA. We conclude that the transient alkalinization, which is a remote effect of chloride stress, modulates the compartmental distribution of ABA between the leaf apoplast and the guard cells and, in this way, is instrumental in inducing stomata closure during the beginning of salinity. PMID:26096890

  20. Diffusion coefficients of nickel chloride in aqueous solutions of lactose at T = 298.15 K and T = 310.15 K

    Binary mutual diffusion coefficients (interdiffusion coefficients) of nickel chloride in water at T = 298.15 K and T = 310.15 K, and at concentrations between (0.000 and 0.100) mol · dm-3, using a Taylor dispersion method have been measured. These data are discussed on the basis of the Onsager-Fuoss and Pikal models. The equivalent conductance at infinitesimal concentration of the nickel ion in these solutions at T = 310.15 K has been estimated using these results. Through the same technique, ternary mutual diffusion coefficients (D11, D22, D12, and D21) for aqueous solutions containing NiCl2 and lactose, at T = 298.15 K and T = 310.15 K, and at different carrier concentrations were also measured. These data permit us to have a better understanding of the structure of these systems and the thermodynamic behaviour of NiCl2 in different media.