Ionization of boric acid in water from 298K to 623K by AC conductivity and Raman spectroscopy

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

doi:10.1016/j.jct.2016.11.007

Cited by 21 publications

(43 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Quantitative equilibrium constants can be determined at near ambient conditions by measuring reduced isotropic spectra with appropriate solvent subtraction methods over a range of concentrations. , The development of high-pressure fused silica capillary cells by Chou and his co-workers allowed Raman methods to be applied to determine formation constants in hydrothermal solutions under acidic and neutral conditions . However, previous studies in this laboratory , have shown that fused silica capillary techniques cannot be used to study borate and polyborate solutions under hydrothermal conditions because the silica walls are quickly corroded.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2019

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

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

et al. 2019

View full text Add to dashboard Cite

show abstract

“…These departures are almost certainly a reflection of the much greater ion pairing in LiOH(aq) cf. the other alkali metal hydroxides, especially at higher temperatures. − …”

Section: Resultsmentioning

confidence: 99%

Molar Volumes and Heat Capacities of Aqueous Solutions of Potassium Hydroxide and for Water Ionization up to 573 K at 10 MPa

et al. 2017

View full text Add to dashboard Cite

Densities (ρ) and isobaric volumetric heat capacities (σ p ) of carefully purified aqueous solutions of potassium hydroxide have been measured at concentrations up to 6 mol•kg −1 at a pressure of 10 MPa over the temperature range 323 ≤ T/K ≤ 573 using a vibrating-tube densimeter and a Tian−Calvet differential calorimeter, respectively. Apparent molar volumes (V ϕ ) and isobaric heat capacities (C pϕ ) calculated from these data were fitted with modified Redlich−Meyer type equations to derive the corresponding standard molar volumes and heat capacities at infinite dilution. Exact comparisons with literature data were not possible because of pressure differences but the present values, which greatly extend the database for KOH(aq) in terms of precision, temperature and concentration, are broadly compatible with most of the earlier results. Comparison of the present values of V ϕ and C pϕ for KOH(aq) with corresponding data for solutions of the other alkali metal hydroxides indicated that all of these systems show similar behavior except for LiOH(aq), probably because of greater ion pairing in the latter. The present results for KOH(aq) were combined with reliable literature data for HCl(aq) and KCl(aq) to estimate the standard molar volume and heat capacity changes for the ionization of water up to 573 K.

show abstract

“…Due to the optical components used, this design cannot be compared with the one presented in this article. In the last 70 years, the development of optical elements has made important progress in coating processes and detector-side sensitivity as well as stabilized, narrow-band laser light sources (Berenblut and Dawson, 1972;Rea et al, 1957;Szymanski, 1967).…”

Section: Raman Photometersmentioning

confidence: 99%

“…Ebrahimi et al (2017) used Raman spectroscopy for in-line monitoring of hydrogen peroxide in twophase reactions. Arcis et al (2017) proposed the application of Raman spectroscopy for monitoring the ionization of boric acid in water for geochemistry, for industrial chemistry and in pressurized water nuclear reactors by measuring Raman shifts at 870 and 930 cm −1 . (Arcis et al, 2016;Ebrahimi, 2017;Esmonde-White et al, 2017;Frauendorfer and Hergeth, 2016;Wang et al, 2017) 3 Material and methods…”

Section: Possible Applicationsmentioning

confidence: 99%

A customized stand-alone photometric Raman sensor applicable in explosive atmospheres: a proof-of-concept study

Nachtmann

Keck

Braun

et al. 2018

J. Sens. Sens. Syst.

View full text Add to dashboard Cite

Abstract. This paper presents an explosion-proof two-channel Raman photometer designed for chemical process monitoring in hazardous explosive atmospheres. Due to its design, alignment of components is simplified and economic in comparison to spectrometer systems. Raman spectrometers have the potential of becoming an increasingly important tool in process analysis technologies as part of molecular-specific concentration monitoring. However, in addition to the required laser power, which restricts use in potentially explosive atmospheres, the financial hurdle is also high. Within the scope of a proof of concept, it is shown that photometric measurements of Raman scattering are possible. The use of highly sensitive detectors allows the required excitation power to be reduced to levels compliant for operation in potentially explosive atmospheres. The addition of an embedded platform enables stable use as a self-sufficient sensor, since it carries out all calculations internally. Multi-pixel photon counters (MPPCs) with large detection areas of 1350 µm2 are implemented as detectors. As a result, the sensitivity of the sensor is strongly increased. This gain in sensitivity is primarily achieved through two characteristics: first, the operating principle “avalanche breakdown” to detect single photons is used; second, the size of the image projected onto the MPPC is much bigger than the pixel area in competing Raman-Spectrometers resulting in higher photon flux. This combination enables reduction of the required excitation power to levels compliant for operation in potentially explosive atmospheres. All presented experiments are performed with strongly attenuated laser power of 35 mW. These include the monitoring of the analytes ethanol and hydrogen peroxide as well as the reversible binding of CO2 to amine. Accordingly, the described embedded sensor is ideally suited as a process analytical technology (PAT) tool for applications in environments with limitations on power input.

show abstract

Ionization of boric acid in water from 298K to 623K by AC conductivity and Raman spectroscopy

Cited by 21 publications

References 37 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

Molar Volumes and Heat Capacities of Aqueous Solutions of Potassium Hydroxide and for Water Ionization up to 573 K at 10 MPa

A customized stand-alone photometric Raman sensor applicable in explosive atmospheres: a proof-of-concept study

Contact Info

Product

Resources

About