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1.
Dhanpat Rai Dean A. Moore Andrew R. Felmy Kevin M. Rosso Harvey BoltonJr. 《Journal of solution chemistry》2010,39(6):778-807
To determine the solubility product of PuPO4(cr, hyd.) and the complexation constants of Pu(III) with phosphate and EDTA, the solubility of PuPO4(cr, hyd.) was investigated as a function of: (1) time and pH (varied from 1.0 to 12.0), and at a fixed 0.00032 mol⋅L−1 phosphate concentration; (2) NaH2PO4 concentrations varying from 0.0001 mol⋅L−1 to 1.0 mol⋅L−1 and at a fixed pH of 2.5; (3) time and pH (varied from 1.3 to 13.0) at fixed concentrations of 0.00032 mol⋅L−1 phosphate and 0.0004 mol⋅L−1 or 0.002 mol⋅L−1 Na2H2EDTA; and (4) Na2H2EDTA concentrations varying from 0.00005 mol⋅L−1 to 0.0256 mol⋅L−1 at a fixed 0.00032 mol⋅L−1 phosphate concentration and at pH values of approximately 3.5, 10.6, and 12.6. A combination of solvent extraction and spectrophotometric
techniques confirmed that the use of hydroquinone and Na2S2O4 helped maintain the Pu as Pu(III). The solubility data were interpreted using the Pitzer and SIT models, and both provided
similar values for the solubility product of PuPO4(cr, hyd.) and for the formation constant of PuEDTA−. The log 10 of the solubility product of PuPO4(cr, hyd.) [PuPO4(cr, hyd.)
\rightleftarrows\rightleftarrows
Pu3++PO43-\mathrm{Pu}^{3+}+\mathrm{PO}_{4}^{3-}] was determined to be −(24.42±0.38). Pitzer modeling showed that phosphate interactions with Pu3+ were extremely weak and did not require any phosphate complexes [e.g., PuPO4(aq), PuH2PO42+\mathrm{PuH}_{2}\mathrm{PO}_{4}^{2+}, Pu(H2PO4)2+\mathrm{Pu(H}_{2}\mathrm{PO}_{4})_{2}^{+}, Pu(H2PO4)3(aq), and Pu(H2PO4)4-\mathrm{Pu(H}_{2}\mathrm{PO}_{4})_{4}^{-}] as proposed in existing literature, to explain the experimental solubility data. SIT modeling, however, required the inclusion
of PuH2PO42+\mathrm{PuH}_{2}\mathrm{PO}_{4}^{2+} to explain the data in high NaH2PO4 concentrations; this illustrates the differences one can expect when using these two different chemical models to interpret
the data. Of the Pu(III)-EDTA species, only PuEDTA− was needed to interpret the experimental data over a large range of pH values (1.3–12.9) and EDTA concentrations (0.00005–0.256 mol⋅L−1). Calculations based on density functional theory support the existence of PuEDTA− (with prospective stoichiometry as Pu(OH2)3EDTA−) as the chemically and structurally stable species. The log 10 value of the complexation constant for the formation of PuEDTA− [
Pu3++EDTA4-\rightleftarrows PuEDTA-\mathrm{Pu}^{3+}+\mathrm{EDTA}^{4-}\rightleftarrows \mathrm{PuEDTA}^{-}] determined in this study is −20.15±0.59. The data also showed that PuHEDTA(aq), Pu(EDTA)45-\mathrm{Pu(EDTA)}_{4}^{5-}, Pu(EDTA)(HEDTA)4−, Pu(EDTA)(H2EDTA)3−, and Pu(EDTA)(H3EDTA)2−, although reported in the literature, have no region of dominance in the experimental range of variables investigated in
this study. 相似文献
2.
Results of the formation of copper sulfide layers using the solutions of elemental sulfur in carbon disulfide as precursor
for sulfurization are presented. Low density polyethylene film can be effectively sulfurized in the solutions of rhombic (α)
sulfur in carbon disulfide. The concentration of sulfur in polyethylene increases with the increase of the temperature and
concentration of sulfur solution in carbon disulfide and it little depends on the duration of sulfurization. Electrically
conductive copper sulfide layers on polyethylene film were formed when sulfurized polyethylene was treated with the solution
of copper (II/I) salts. CuxS layer with the lowest sheet resistance (11.2 Ω cm−2) was formed when sulfurized polyethylene was treated with copper salts solution at 80°C. All samples with formed CuxS layers were characterized by X-ray photoelectron spectroscopy. XPS analysis of obtained layers showed that on the layer’s
surface and in the etched surface various compounds of copper, sulfur and oxygen are present: Cu2S, CuS, CuO, S8, CuSO4, Cu(OH)2 and water. The biggest amounts of CuSO4 and Cu(OH)2 are present on the layer’s surface. Significantly more copper sulfides are found in the etched layers. 相似文献
3.
Yu. A. Titov N. S. Slobodyanik V. V. Polubinskii V. V. Chumak 《Theoretical and Experimental Chemistry》2012,47(6):394-398
We have established and analyzed the sequences of phase transitions in synthesis of layered compounds in the AnBn–1O3n family (
\textA3\textII\textLnB3\textV\textO12 {\text{A}}_3^{\text{II}}{\text{LnB}}_3^{\text{V}}{{\text{O}}_{{12}}} (AII = Ba, Sr, Ln = La, Nd, BV = Nb, Ta) and La4Ti3O12 with n = 4) from coprecipitated hydroxocarbonate and hydroxide systems, including steps involving the formation, solid-phase
reaction, or structural rearrangement of intermediates. 相似文献
4.
Solubility measurements as a function of temperature have been shown to be a powerful tool for the determination of thermodynamic properties of sparingly-soluble transition metal carbonates. In contrast to calorimetric methods, such as solution calorimetry or drop calorimetry, the evaluation of solubility data avoids many systematic errors, yielding the enthalpy of solution at 298.15 K with an estimated uncertainty of ±3 kJ · mol−1. A comprehensive set of thermodynamic data for otavite (CdCO3), smithsonite (ZnCO3), hydrozincite (Zn5(OH)6(CO3)2), malachite (Cu2(OH)2CO3), azurite (Cu3(OH)2(CO3)2), and siderite (FeCO3) was derived. Literature values for the standard enthalpy of formation of malachite and azurite were disproved by these solubility experiments, and revised values are recommended. In the case of siderite, data for the standard enthalpy of formation given by various data bases deviate from each other by more than 10 kJ · mol−1 which can be attributed to a discrepancy in the auxiliary data for the Fe2+ ion. A critical evaluation of solubility data from various literature sources results in an optimized value for the standard enthalpy of formation for siderite. The Davies approximation, the specific ion-interaction theory, and the Pitzer concept are used for the extrapolation of the solubility constants to zero ionic strength in order to obtain standard thermodynamic properties valid at infinite dilution, T = 298.15 K, and p = 105 Pa. The application of these electrolyte models to both homogeneous and heterogeneous (solid-solute) equilibria in aqueous solution is reviewed. 相似文献
5.
Summary. Solubility measurements as a function of temperature have been shown to be a powerful tool for the determination of thermodynamic
properties of sparingly-soluble transition metal carbonates. In contrast to calorimetric methods, such as solution calorimetry
or drop calorimetry, the evaluation of solubility data avoids many systematic errors, yielding the enthalpy of solution at
298.15 K with an estimated uncertainty of ±3 kJ · mol−1. A comprehensive set of thermodynamic data for otavite (CdCO3), smithsonite (ZnCO3), hydrozincite (Zn5(OH)6(CO3)2), malachite (Cu2(OH)2CO3), azurite (Cu3(OH)2(CO3)2), and siderite (FeCO3) was derived. Literature values for the standard enthalpy of formation of malachite and azurite were disproved by these solubility
experiments, and revised values are recommended. In the case of siderite, data for the standard enthalpy of formation given
by various data bases deviate from each other by more than 10 kJ · mol−1 which can be attributed to a discrepancy in the auxiliary data for the Fe2+ ion. A critical evaluation of solubility data from various literature sources results in an optimized value for the standard
enthalpy of formation for siderite. The Davies approximation, the specific ion-interaction theory, and the Pitzer concept are used for the extrapolation of the solubility constants to zero ionic strength in order to obtain standard thermodynamic
properties valid at infinite dilution, T = 298.15 K, and p = 105 Pa. The application of these electrolyte models to both homogeneous and heterogeneous (solid-solute) equilibria in aqueous
solution is reviewed.
Received June 26, 2001. Accepted July 2, 2001 相似文献
6.
Changzhou Yuan Long Yang Linrui Hou Diankai Li Laifa Shen Fang Zhang Xiaogang Zhang 《Journal of Solid State Electrochemistry》2012,16(4):1519-1525
A facile hydrothermal strategy was first proposed to synthesize flower-like Co(OH)2 hierarchical microspheres. Further physical characterizations revealed that the flower-like Co(OH)2 microspherical superstructures were self-assembled by one-dimension nanobelts with rich mesopores. Electrochemical performance
of the flower-like Co(OH)2 hierarchical superstructures were investigated by cyclic voltammgoram, galvanostatic charge–discharge and electrochemical
impedance spectroscopy in 3 M KOH aqueous electrolyte. Electrochemical data indicated that the flower-like Co(OH)2 superstructures delivered a specific capacitance of 434 F g−1 at 10 mA cm−2 (about 1.33 A g−1), and even kept it as high as 365 F g−1 at about 5.33 A g−1. Furthermore, the SC degradation of about 8% after 1,500 continuous charge–discharge cycles at 5.33 A g−1 demonstrates their good electrochemical stability at large current densities. 相似文献
7.
J. M. Santana-Casiano M. González-Dávila F. J. Millero 《Journal of solution chemistry》2008,37(6):749-762
The stability constants for the hydrolysis of Cu(II) and formation of chloride complexes in NaClO4 solution, at 25 °C, have been examined using the Pitzer equations. The calculated activity coefficients of CuOH+, Cu(OH)2, Cu2(OH)3+, Cu2(OH)22+, CuCl+ and CuCl2 have been used to determine the Pitzer parameter (β
i
(0), β
i
(1), and C
i
) for these complexes. These parameters yield values for the hydrolysis constants (log 10
β
1*, log 10
β
2*, log 10
β
2,1* and log 10
β
2,2*) and the formation of the chloride complexes (log 10
β
CuCl* and
that agree with the experimental measurements, respectively to ±0.01,±0.02,±0.03,±0.06,±0.03 and ±0.07.
The stability constants for the hydrolysis and chloride complexes of Cu(II) were found to be related to those of other divalent
metals over a wide range of ionic strength. This has allowed us to use the calculated Pitzer parameters for copper complexes
to model the stability constants and activity coefficients of hydroxide and chloride complexes of other divalent metals. The
applicability of the Pitzer Cu(II) model to the ionic strength dependence of hydrolysis of zinc and cadmium is presented.
The resulting thermodynamic hydroxide and chloride constants for zinc are
and
. For cadmium the thermodynamic hydrolysis constants are
and
. The Cu(II) model allows one to determine the stability of other divalent metal complexes over a wide range of concentration
when little experimental data are available. More reliable stepwise stability constants for divalent metals are needed to
test the linearity found for the chloro complexes. 相似文献
8.
Dhanpat Rai Dean A. Moore Nancy J. Hess Kevin M. Rosso Linfeng Rao Steve M. Heald 《Journal of solution chemistry》2007,36(10):1261-1285
Chromium(III)-carbonate reactions are expected to be important in managing high-level radioactive wastes. Extensive studies
on the solubility of amorphous Cr(III) hydroxide solid in a wide range of pH (3–13) at two different fixed partial pressures
of CO2(g) (0.003 or 0.03 atm.), and as functions of K2CO3 concentrations (0.01 to 5.8 mol⋅kg−1) in the presence of 0.01 mol⋅dm−3 KOH and KHCO3 concentrations (0.001 to 0.826 mol⋅kg−1) at room temperature (22±2 °C) were carried out to obtain reliable thermodynamic data for important Cr(III)-carbonate reactions.
A combination of techniques (XRD, XANES, EXAFS, UV-Vis-NIR spectroscopy, thermodynamic analyses of solubility data, and quantum
mechanical calculations) was used to characterize the solid and aqueous species. The Pitzer ion-interaction approach was used
to interpret the solubility data. Only two aqueous species [Cr(OH)(CO3)22− and Cr(OH)4CO33−] are required to explain Cr(III)-carbonate reactions in a wide range of pH, CO2(g) partial pressures, and bicarbonate and carbonate concentrations. Calculations based on density functional theory support
the existence of these species. The log 10
K° values of reactions involving these species [{Cr(OH)3(am) + 2CO2(g)⇌Cr(OH)(CO3)22−+2H+} and {Cr(OH)3(am) + OH−+CO32−
⇌Cr(OH)4CO33−}] were found to be −(19.07±0.41) and −(4.19±0.19), respectively. No other data on any Cr(III)-carbonato complexes are available
for comparisons. 相似文献
9.
M. Prabu S. Selvasekarapandian M. V. Reddy B. V. R. Chowdari 《Journal of Solid State Electrochemistry》2012,16(5):1833-1839
Olivine-structured LiCoPO4 is synthesized by a Pechini-type polymer precursor method. The structure and the morphology of the compounds are studied
by the Rietveld-refined X-ray diffraction, scanning electron microscopy, Brunauer, Emmett, and Teller surface area technique,
infrared spectroscopy, and Raman spectroscopy techniques, respectively. The ionic conductivity (σ ionic), dielectric, and electric modulus properties of LiCoPO4 are investigated on sintered pellets by impedance spectroscopy in the temperature range, 27–50 °C. The σ (ionic) values at 27 and 50 °C are 8.8 × 10−8 and 49 × 10−8 S cm−1, respectively with an energy of activation (E
a) = 0.43 eV. The electric modulus studies suggest the presence of non-Debye type of relaxation. Preliminary charge–discharge
cycling data are presented. 相似文献
10.
H. López-González M. Jiménez-Reyes M. Solache-Ríos A. Rojas-Hernández 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(1):103-108
Solubility product (Lu(OH)3(s)⇆Lu3++3OH−) and first hydrolysis (Lu3++H2O⇆Lu(OH)2++H+) constants were determined for an initial lutetium concentration range from 3.72·10−5 mol·dm−3 to 2.09·10−3 mol·dm−3. Measurements were made in 2 mol·dm−3 NaClO4 ionic strength, under CO2-free conditions and temperature was controlled at 303 K. Solubility diagrams (pLuaq vs. pC
H) were determined by means of a radiochemical method using 177Lu. The pC
H for the beginning of precipitation and solubility product constant were determined from these diagrams and both the first
hydrolysis and solubility product constants were calculated by fitting the diagrams to the solubility equation. The pC
H values of precipitation increases inversely to [Lu3+]initial and the values for the first hydrolysis and solubility product constants were log10
β*
Lu,H
= −7.92±0.07 and log10
K*sp,Lu(OH)3 = −23.37±0.14. Individual solubility values for pC
H range between the beginning of precipitation and 8.5 were S
Lu3+ = 3.5·10−7 mol·dm−3, S
Lu(OH)2+ = 6.2·10−7 mol·dm−3, and then total solubility was 9.7·10−7 mol·dm−3. 相似文献
11.
Matthias Weil Franz Werner Frank Kubel 《Monatshefte für Chemie / Chemical Monthly》2002,133(3):267-275
Summary. Single crystals of MgAl2F8(H2O)2 have been obtained under hydrothermal conditions (250°C, 14 d) from a starting mixture of AlF3 and MgAlF5(H2O)2 in a 5% (w/w) HF solution. The crystal structure has been determined and refined from single crystal data (Fmmm (#69), Z = 4, a = 7.2691(7), b = 7.0954(16), c = 12.452(2) ?, 281 structure factors, 27 parameters, R(F
2 > 2σ (F
2)) = 0.0282, wR(F
2 all) = 0.0885). The obtained crystals were systematically twinned according to (010/100/001) as twinning matrix, reflecting
the pseudo-tetragonal metric. The crystal structure is composed of perowskite-type layers built of corner sharing AlF6 octahedra with an overall composition of AlF4
− which are connected via common fluorine atoms of [MgF4/2(H2O)2/1] octahedra. Group-subgroup relations of MgAl2F8(H2O)2 to WO3(H2O)0.33 and to other M(II)M(III)2 F8(H2O)2 structures are briefly discussed. Above 570°C, MgAl2F8(H2O)2 decomposes under elimination of water into α-AlF3, β-AlF3, and MgF2.
Received October 29, 2001. Accepted (revised) December 6, 2001 相似文献
12.
The dissolution of ThO<Subscript>2</Subscript>(cr) in carbonate solutions and a granitic groundwater
S. S. Kim M. H. Baik J. W. Choi H. S. Shin J. I. Yun 《Journal of Radioanalytical and Nuclear Chemistry》2010,286(1):91-97
ThO2(cr) was dissolved in the solutions containing various carbonate ion concentrations, and the results were compared with thorium
solubility in a domestic granitic groundwater having very low ionic strength. The soluble thorium concentration excluding
colloids after phase separation increased with increasing carbonate concentration. However, the thorium concentration in the
real groundwater was remarkably greater than that in the carbonate-containing solutions with a similar concentration of carbonate
and pH condition. This might be attributable to other species as well as Th(OH)4(aq) and Th(OH)3(CO3)−. These species form colloids or precipitates, and their concentration can be reduced in the ultra-filtered solution by an
aging effect. 相似文献
13.
Zhao Yang Gao-Shao Cao Jian Xie Xin-Bing Zhao 《Journal of Solid State Electrochemistry》2012,16(3):1271-1277
LiMnPO4, with a particle size of 50–150 nm, was prepared by oleic acid-assisted solid-state reaction. The materials were characterized
by X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. The electrochemical
properties of the materials were investigated by galvanostatic cycling. It was found that the introduction of oleic acid in
the precursor led to smaller particle size and more homogeneous size distribution in the final products, resulting in improved
electrochemical performance. The electrochemical performance of the sample could be further enhanced by Co doping. The mechanism
for the improvement of the electrochemical performance was investigated by Li-ion chemical diffusion coefficient
( [(D)\tilde]\textLi ) \left( {{{\tilde{D}}_{\text{Li}}}} \right) and electrochemical impedance spectroscopy measurements. The results revealed that the
[(D)\tilde]\textLi {\tilde{D}_{\text{Li}}} values of LiMnPO4 measured by cyclic voltammetry method increase from 9.2 × 10−18 to 3.0 × 10−17 cm2 s−1 after Co doping, while the charge transfer resistance (R
ct) can be decreased by Co doping. 相似文献
14.
We have determined the parameters of the Arrhenius equation (E, log A) for reactions between
\textNO2+ {\text{NO}}_2^{+} ions and C3-C8 alkanes in HNO3–93 wt.% H2SO4 solutions at 277–353 K, and we have also estimated the activation parameters E
j
, log A
j
for secondary and tertiary C—H bonds of these alkanes. We show that the following compensation relations are satisfied: E = 2.3R βlog A + C with isokinetic temperature β = 360 ± 65 K, and also E
j
=2.3Rβ
j
log A
j
+ C
j
, for secondary C—H bonds, β2 =300 ± 60, and for tertiary C—H bonds, β3 =310 ± 50. 相似文献
15.
The deuterium-isotope effects on the ionization constants of β-naphthol (2-naphthol) and boric acid, Δlog 10
K=[log 10
K
D2O−log 10
K
H2O], have been determined from measurements in light and heavy water at temperatures from 225 °C≤t≤300 °C and pressures near steam saturation. β-Naphthol is a thermally-stable colorimetric pH indicator, whose ionization constant lies close to that of H2PO4− (aq), the only acid for which Δlog 10
K is accurately known at elevated temperatures. A newly designed platinum flow cell was used to measure UV-visible spectra
of β-naphthol in acid, base, and buffer solutions of H2PO4−/HPO42− and D2PO4−/DPO42−, from which the degree of ionization at known values of pH and pD was determined. Values of the ionization constants of β-naphthol in light and heavy water were calculated from these results, and used to derive a model for
and
over the experimental temperature range with an estimated precision of ±0.02 in log 10
K. The new values of K
H2O and K
D2O allowed us to use β-naphthol as a colorimetric indicator, to measure the equilibrium pH and pD of the buffer solutions B(OH)3/B(OH)4− and B(OD)3/B(OD)4− up to 300 °C, from which the ionization constants of boric acid were calculated. The magnitude of the deuterium isotope effect
for H2PO4− (aq) is known to fall from Δlog 10
K=−0.62 to Δlog 10
K=−0.47, on the “aquamolal” concentration scale, as the temperature rises above 125 °C, but then remains almost constant. Although
the temperature range is more limited, the new results for β-naphthol and boric acid appear to show a similar trend. 相似文献
16.
Peter Klampfer Primož Benkič Maja Ponikvar Ana Rahten Antonija Lesar Adolf Jesih 《Monatshefte für Chemie / Chemical Monthly》2003,134(1):1-9
Summary. Hydrazinium(+2) fluoroarsenate(III) fluoride was prepared by the reaction of hydrazinium(+2) fluoride and liquid arsenic
trifluoride. N2H6AsF4F is stable at 273 K, but decomposes slowly at room temperature. N2H6AsF4F crystallizes in the orthorhombic space group Pnn2 with a = 774.0(2) pm, b = 1629.2(4) pm and c = 436.6(1) pm; V = 0.5506(3) nm3, Z = 4 and d
c
= 2.461 g cm−3. The structure consists of N2H6
2+ cations, AsF4
− anions, and F− anions and is interconnected by a hydrogen bonding network. Distorted trigonal-bipyramidal AsF4
− units are very weakly interconnected and form chains along the b axis. Bands in the Raman spectrum are assigned to the vibrations of N2H6
+2 cations and AsF4
− anions.
Corresponding author. E-mail: adolf.jesih@ijs.si
Received April 18, 2002; accepted July 15, 2002 相似文献
17.
The hydrolytic behavior of antimonic acid, Sb(OH)5o, was experimentally investigated, at fixed temperatures within the range 10–40 °C, by both titration of dilute Na-antimonate
solutions with HClO4 and single-point pH measurements of diluted Sb(OH)5o solutions. The thermodynamic constants, K
a, for the reaction:
were derived at different controlled temperatures, based on pH measurements, applying suitable mass and electrical balances
and correcting the concentrations of ionic species for medium effects. From the resulting log 10
K
a values, those of the corresponding isocoulombic equilibrium reaction:
were computed and used to derive its thermodynamic properties. These were finally combined with the corresponding thermodynamic
properties of the water association reaction, to obtain robust estimations of ΔG
ro, ΔS
ro and ΔH
ro for the ionogenic reaction. These are the first thermodynamic data at temperatures different from 25 °C for the ionization
reaction of Sb(OH)5o. The results of the present work confirm that Sb(OH)5o is a moderately weak and monoprotic acid with a pK
a of 2.848 at 25 °C. 相似文献
18.
Crystalline zinc silicate, Zn2SiO4, and zinc ferrite, ZnFe2O4, were prepared and characterized. The solubilities of these phases were measured using flow-through apparatus from 50 to
350 °C in 100 °C intervals over a wide range of pH. Both solid phases dissolve incongruently, presumably to form ZnO(s) and
Fe2O3(s) (or the corresponding hydroxide phases at low temperature), respectively. The respective concentrations of zinc(II) and
iron(III) matched those of ZnO(cr) and Fe2O3(s) (≥150 °C) reported in the literature, whereas the corresponding Si(IV) and Zn(II) concentrations were at least an order
of magnitude below the solubility limits for their pure oxide phases. Therefore, the solubility constants for zinc silicate
and ferrite were determined with respect to the known solubility constants for ZnO(cr) and Fe2O3(s) (≥150 °C), respectively, and the corresponding concentrations of Si(IV) and Zn(II) measured in this study. The results
of independent experiments, as well as those reported in the literature provide insights into the mechanism(s) of formation
of zinc silicate and ferrite in the primary circuits of nuclear reactors.
D.A. Palmer is retired. 相似文献
19.
Dhanpat Rai Mikazu Yui H. Todd Schaef Akira Kitamura 《Journal of solution chemistry》2010,39(7):999-1019
Prior to this study no data for the solubility product of BiPO4(cr) or the complexation constants of Bi with phosphate were available. The solubility of BiPO4(cr) was studied at 23±2?°C from both the over- and under-saturation directions as functions of a wide range in time (6–309 days), pH values (0–15), and phosphate concentrations (reaching as high as 1.0 mol?kg?1). HCl or NaOH were used to obtain a range in pH values. Steady state concentrations and equilibrium were reached in <6 days. The data were interpreted using the SIT model. These extensive data provided a solubility product value for BiPO4(cr) and an upper limit value for the formation of BiPO4(aq). Because the aqueous system in this study involved relatively high concentrations of chloride, reliable values for the complexation constants of Bi with chloride were required to accurately interpret the solubility data. Therefore as a part of this investigation, existing Bi–Cl data were critically reviewed and used to obtain values of equilibrium constants for various Bi–Cl complexes at zero ionic strength along with the values for various SIT ion interaction parameters. Predictions based on these thermodynamic quantities agreed closely with our experimental data, the chloride concentrations of which ranged as high as 0.7 mol?kg?1. The study showed that BiPO4(cr) is stable at pH values <9.0. At pH values >9.0, Bi(OH)3(am) is the solubility controlling phase. Reliable values for the Bi(OH)3(am) solubility reactions involving Bi(OH)3(aq) and $\mathrm{Bi}(\mathrm{OH})_{4}^{-}$ and the formation constants of these aqueous species are also reported. 相似文献
20.
J. Dailly F. Mauvy M. Marrony M. Pouchard Jean-Claude Grenier 《Journal of Solid State Electrochemistry》2011,15(2):245-251
Three selected materials have been prepared and shaped as cathode of half cells using the proton-conducting electrolyte BaCe0.9Y0.1O3 − δ
(BCY10): two perovskite compounds, Ba0.5Sr0.5Co0.8Fe0.2O3 − δ
(BSCF) and La0.6Sr0.4Fe0.8Co0.2O3 − δ
(LSFC), and the praseodymium nickelate Pr2NiO4 + δ
(PRN) having the K2NiF4-type structure. The electrochemical properties of these compounds have been studied under zero current conditions (two-electrode
cell) and under polarization (three-electrode cell). Their measured area-specific resistances were about 1–2 Ω cm2 at 600 °C. Under direct current polarization, it appears that the three compounds show almost similar values of current densities
at 625 °C; however, at lower temperatures, BSCF appears to be the most efficient cathode material. 相似文献