Ion-Pair Formation Constants of Lithium Borate and Lithium Hydroxide under Pressurized Water Nuclear Reactor Coolant Conditions

Ferguson, Jane P.; Arcis, Hugues; Zimmerman, G. H.; Tremaine, Peter R.

doi:10.1021/acs.iecr.7b01015

Cited by 15 publications

(25 citation statements)

References 53 publications

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“…The MULTEQ model uses the Marshall and Franck expression for K w , while the OLI model is based on the treatment by Tanger and Helgeson . The impact of the formulation used for K w is discussed in more detail in our recent lithium borate study …”

Section: Discussionmentioning

confidence: 99%

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Triborate Formation Constants and Polyborate Speciation under Hydrothermal Conditions by Raman Spectroscopy using a Titanium/Sapphire Flow Cell

et al. 2019

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Solvent-corrected reduced isotropic Raman spectra of aqueous boric acid + sodium borate solutions have been obtained from perpendicular and parallel polarization measurements in a novel custom-made titanium flow cell with sapphire windows over the temperature range 25 to 300 °C at 20 MPa using the perchlorate anion, ClO4 –, as an internal standard. The reduced isotropic spectra of solutions yielded the first reported quantitative speciation results for polyborate ions in equilibrium with boric acid and borate in high-temperature aqueous solutions above 200 °C. The spectra obtained from solutions at low sodium/boron ratios, 0 < m Na ST/m B ST < 0.254, displayed well-defined bands at 880, 747, 615, and 532 cm−1, corresponding to the species B(OH)3 > [B(OH)4]− > [B3O3(OH)4]− ≫ [B5O6(OH)4]−, respectively. The triborate ion, [B3O3(OH)4]−, was found to be the major polyborate species in these boric acid-rich solutions in the range 25 to 300 °C. Thermodynamic formation constants for the triborate species, [B3O3(OH)4]−, calculated from the peak areas, are in agreement with the literature values reported by Mesmer et al at 50, 100, and 200 °C to within the combined experimental uncertainties. At 300 °C, the value for the formation constant, log K 31,m b = 2.259 ± 0.060, is larger than the value extrapolated from the results of Mesmer et al. by a factor of ∼3.

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Section: Discussionmentioning

confidence: 99%

“…34 The impact of the formulation used for K w is discussed in more detail in our recent lithium borate study. 37…”

Section: Discussionmentioning

confidence: 99%

Triborate Formation Constants and Polyborate Speciation under Hydrothermal Conditions by Raman Spectroscopy using a Titanium/Sapphire Flow Cell

et al. 2019

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“…The TBBK Model. The concentration dependence of the solution conductivity was modeled with the same data treatment strategy used in previous work on ion association in metal borate solutions, 9,10 in which the TBBK model 20 was used together with the mixing rule reported by Sharygin et al 22…”

Section: Tbbk Conductivity Data Analysismentioning

confidence: 99%

“…In 2000, Palmer re-evaluated the literature data for borate and polyborates and developed expressions for the formation constants as functions of solvent density, temperature, and ionic strength. More recent work in our laboratory reported accurate ionization constants of boric acid and ion-pair formation constants of alkali metal borates from 298 to 623 K. , Our work on alkali metal borates included the determination of temperature-dependent values for the limiting conductivity of borate. No accurate values for the limiting conductivities of polyborates have been reported in the literature.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics of Polyborates under Hydrothermal Conditions: Formation Constants and Limiting Conductivities of Triborate and Diborate

2019

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Frequency-dependent molar electrical conductivities for aqueous solutions of boric acid with small additions of sodium hydroxide or potassium hydroxide have been measured from 298 to 573 K at 12 MPa to an accuracy of ±3%, using a unique high-precision flow-through AC conductance instrument. The measurements were made to yield accurate polyborate equilibrium formation constants and limiting conductivities under the primary coolant conditions of pressurized water nuclear reactors (PWRs). Complementary measurements from T = 283 K to T = 313 K at p = 0.1 MPa were completed using a commercial conductivity probe to extend the data to lower temperatures. Up to 423 K, measurements were performed under conditions where the triborate ion B3O3(OH)4 – is the major anionic species in solution. At temperatures above 473 K, the conditions favored the formation of a different anionic species, which was assigned to be the diborate ion B2(OH)7 –. The analysis of the concentration dependence of the molar conductivity data using the TBBK equation yielded limiting conductivities, λ0, and formation constants, K b 31,m and K b 21,m , for triborate and diborate from 283 to 473 K, and from 473 to 573 K, respectively. These results are consistent with the only other experimental study that has reported equilibrium constants for aqueous polyborates above 373 K (Mesmer et al. Inorg. Chem. 1972, 11, 537). The limiting conductivities are the first to be reported in the literature.

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“…Thus far, at least five types of borate species, [B(OH) 3 ], [B(OH) 4 − ], [B 3 O 3 (OH) 4 − ], [B 4 O 5 (OH) 4 2− ], and [B 5 O 6 (OH) 4 − ], have been found in solution, and the amount of them varies with environmental conditions. In recent years, studies have shown that many factors, such as pH, counter‐ions, temperature, and equilibrium time, affect transformations among borate ions in solution. The borate species have a higher level of hydration and hydrolysis in dilute solution, where high‐polymerization borate anions hydrolyze into low‐polymerization borate anions, such as [B(OH) 3 ] and [B(OH) 4 − ].…”

Section: Introductionmentioning

confidence: 99%

Mechanism for hydrolysis of double six‐membered ring tetraborate anion

Zhou

Zhu

Liu

et al. 2019

Int J of Quantum Chemistry

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[B4O5(OH)42−] is a representative borate anion with a double six‐membered ring structure, but there is limited knowledge about the hydrolysis mechanisms of [B4O5(OH)42−]. Density functional theory‐based calculations show that the tetraborate ion undergoes three‐step hydrolysis to form [B(OH)4−] and an ring intermediate, [B3O2(OH)6−]. Other new structures, such as linear trimer, branched tetraborate, analogous linear tetraborate, are observed, but they are not stable in neutral systems and change to ring structures. [B3O2(OH)6−] hydrolyzes to [B(OH)4−] and [B(OH)3] in the last two steps. The structure of borate anion and the coordination environment of the bridge oxygen atom control the hydrolysis process. [B4O5(OH)42−] always participates in the hydrolysis reaction, even with a decrease in concentration. [B3O3(OH)4−], [B(OH)4−], and [B(OH)3] have different roles in “water‐poor” and “water‐rich” zones. Concentration and pH of solution are the key factors that affect the distribution of borate ions.

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Ion-Pair Formation Constants of Lithium Borate and Lithium Hydroxide under Pressurized Water Nuclear Reactor Coolant Conditions

Cited by 15 publications

References 53 publications

Triborate Formation Constants and Polyborate Speciation under Hydrothermal Conditions by Raman Spectroscopy using a Titanium/Sapphire Flow Cell

Triborate Formation Constants and Polyborate Speciation under Hydrothermal Conditions by Raman Spectroscopy using a Titanium/Sapphire Flow Cell

Thermodynamics of Polyborates under Hydrothermal Conditions: Formation Constants and Limiting Conductivities of Triborate and Diborate

Mechanism for hydrolysis of double six‐membered ring tetraborate anion

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