Weak barium and radium hydrolysis using an ion exchange method and its uncertainty assessment

Matyskin, Artem V.; Brown, Paul L.; Ekberg, Christian

doi:10.1016/j.jct.2018.08.037

Cited by 10 publications

(12 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The pH of all samples was measured after the last sampling and was always above 12. Radium hydrolysis at this pH is very weak and can be neglected …”

Section: Methodsmentioning

confidence: 99%

“…Radium hydrolysis at this pH is very weak and can be neglected. 16 After centrifugation, two 10 μL samples were taken and the concentration of 226 Ra was measured using a High Purity Germanium Detector (Ortec GEM-C5060 coaxial high purity germanium detector 50.5 mm diameter, 68.3 mm length, and 0.9 mm carbon epoxy entrance window coupled to a digital spectrum analyzer Ortec DSPEC50). The detector was calibrated for the same geometry (1 mL of 4 mol•L −1 HCl in polypropylene tube) using a mixed radionuclide reference solution (NIST traceable from Eckert and Ziegler, USA).…”

Section: Synthesis Of Radium Carbonatementioning

confidence: 99%

See 1 more Smart Citation

Disordered Crystal Structure and Anomalously High Solubility of Radium Carbonate

et al. 2023

Self Cite

View full text Add to dashboard Cite

Radium-226 carbonate was synthesized from radium−barium sulfate ( 226 Ra 0.76 Ba 0.24 SO 4 ) at room temperature and characterized by X-ray powder diffraction (XRPD) and extended X-ray absorption fine structure (EXAFS) techniques. XRPD revealed that fractional crystallization occurred and that two phases were formed�the major Ra-rich phase, Ra(Ba)CO 3 , and a minor Ba-rich phase, Ba(Ra)CO 3 , crystallizing in the orthorhombic space group Pnma (no. 62) that is isostructural with witherite (BaCO 3 ) but with slightly larger unit cell dimensions. Direct-space ab initio modeling shows that the carbonate oxygens in the major Ra(Ba)CO 3 phase are highly disordered. The solubility of the synthesized major Ra(Ba)CO 3 phase was studied from under-and oversaturation at 25.1 °C as a function of ionic strength using NaCl as the supporting electrolyte. It was found that the decimal logarithm of the solubility product of Ra(Ba)CO 3 at zero ionic strength (log 10 K sp 0 ) is −7.5(1) (2σ) (s = 0.05 g•L −1 ). This is significantly higher than the log 10 K sp 0 of witherite of −8.56 (s = 0.01 g•L −1 ), supporting the disordered nature of the major Ra(Ba)CO 3 phase. The limited co-precipitation of Ra 2+ within witherite, the significantly higher solubility of pure RaCO 3 compared to witherite, and thermodynamic modeling show that the results obtained in this work for the major Ra(Ba)CO 3 phase are also applicable to pure RaCO 3 . The refinement of the EXAFS data reveals that radium is coordinated by nine oxygens in a broad bond distance distribution with a mean Ra−O bond distance of 2.885(3) Å (1σ). The Ra−O bond distance gives an ionic radius of Ra 2+ in a 9-fold coordination of 1.545(6) Å (1σ).

show abstract

“…The pH of all samples was measured after the last sampling and was always above 12. Radium hydrolysis at this pH is very weak and can be neglected …”

Section: Methodsmentioning

confidence: 99%

Section: Synthesis Of Radium Carbonatementioning

confidence: 99%

Disordered Crystal Structure and Anomalously High Solubility of Radium Carbonate

et al. 2023

Self Cite

View full text Add to dashboard Cite

show abstract

“…Such a large difference in K 0 a can be explained by the problems associated with experimental or theoretical determination of stability constants of weak ion pairs and strongly indicates that uncertainty associated with this value is large. 63,64 In this work apparent stability constant of HNO 0 3 at 4 mol L À1 (K a ) and its 1s standard deviation was estimated based on literature data as 25 AE 10. This value is in a good agreement with most of the literature values discussed by Levanov and co-workers.…”

Section: Determination Of the Stoichiometry Of The Extracted Speciesmentioning

confidence: 99%

Effect of diluent on the extraction of europium(iii) and americium(iii) with N,N,N′,N′-tetraoctyl diglycolamide (TODGA)

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…228 Ra ( t 1/2 = 5.7 years) and 226 Ra ( t 1/2 = 1585 years) are present in the industrial waste from mining and gas operations due to their presence in the 232 Th and 238 U decay chains, respectively. Matyskin et al 17 , 18 recently determined the crystal structure of the environmentally relevant radium-barium sulfate, as well as the hydrolysis behavior of Ra 2+ (aq) . An exceptionally high coordination number of 12 (compared to 8–10 for other heavy radionuclides, Fig.…”

Section: Mobility Of Long-lived Radionuclides In the Environment: Pro...mentioning

confidence: 99%

Open questions on the environmental chemistry of radionuclides

2020

View full text Add to dashboard Cite

Understanding the biogeochemistry of radionuclides in the environment is essential for effective isolation of nuclear waste in repositories, management of contaminated sites, ensuring long-term protection of our ecosystems, and limiting impacts on human health. Here the authors discuss the extreme complexity of this multidimensional chemistry problem, highlighting the outstanding open questions for the next generations of environmental radiochemists.

show abstract

Weak barium and radium hydrolysis using an ion exchange method and its uncertainty assessment

Cited by 10 publications

References 41 publications

Disordered Crystal Structure and Anomalously High Solubility of Radium Carbonate

Disordered Crystal Structure and Anomalously High Solubility of Radium Carbonate

Effect of diluent on the extraction of europium(iii) and americium(iii) with N,N,N′,N′-tetraoctyl diglycolamide (TODGA)

Open questions on the environmental chemistry of radionuclides

Contact Info

Product

Resources

About