Multiple investigations of aqueous Eu(<scp>iii</scp>)–oxalate complexes: the reduction in coordination number and validation of spectral linear correlation

Xian, Dongfan; Zhou, Wanqiang; Wang, Jingyi; Pan, Duoqiang; Li, Xiaolong; Li, Yao; Shi, Yanlin; Wu, Wangsuo; Tan, Zhixin; Liu, Chunli

doi:10.1039/d1dt00609f

Cited by 7 publications

(6 citation statements)

References 57 publications

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“…These N(H 2 O) values are in good agreement with the powder XRD results described above: there are three H 2 O molecules per Eu( iii ) in Eu 2 (Ox) 3 (H 2 O) 6 and Eu 2 (Mal) 3 (H 2 O) 6 , and one in Eu 2 (Suc) 3 (H 2 O) 2 . In contrast to the proposed reduction of the Eu( iii ) coordination number to eight upon binding of two or more Ox ligands, 33 the current results show that the Eu( iii ) coordination number remains nine in solid compounds as well as in aqueous complexes. 10,11 …”

Section: Resultscontrasting

confidence: 99%

Structural and spectroscopic studies of spontaneously formed crystalline Eu(iii)–aliphatic dicarboxylates at room temperature

et al. 2022

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Section: Resultscontrasting

confidence: 99%

Structural and spectroscopic studies of spontaneously formed crystalline Eu(iii)–aliphatic dicarboxylates at room temperature

et al. 2022

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“…It was hypothesized that free [H + ] in aqueous solution might be equal to the final pH; thus, the final pH can be used to calculate a value of free [H + ], which ranged from 4 to 8 per three HBPA molecules. H + released was up to about 67 percent of the total protons of HBPA (2/3 mol/mol) at 30 °C, indicating that more or less [H + ] ions were still bound in Er(III) bisphosphonate complexes, and various Er(III) bisphosphonate hydrated complexes may be formed as illustrated in Figure 3b, which is similar to the formation of different types of Eu(III)-oxalate species complexes in previous research [67]. To evaluate and compare the effects of reaction times on the residual concentration of Er(III) ions, reactions were performed using different times with different dosages.…”

Section: Effect Of the Hbpa Dosage On Er(iii) Removalsupporting

confidence: 83%

Removal of Low Concentrations of Er(III) from Water Using Heptadecyl-1,1-bisphosphonic Acid

Bai,

Yang,

2024

Minerals

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The removal of low concentrations of rare-earth ions (e.g., Er(III)) from water has stimulated interest in the field of mineral processing and water treatment. Here, an ion-exchange and complexation-assisted precipitation method for the removal of low concentrations of Er(III) from water using heptadecyl-1,1-bisphosphonic acid (HBPA) was investigated. The results showed that effective cation-exchange between Er(III) ions and the bisphosphonate headgroup was achieved, and the solution pH abruptly decreased from 6.5 to around 3.1 at the first stage, which further led to the formation of less soluble Er(III) heptadecyl-1,1-bisphosphonate complexes. While low concentrations of Er(III) ions in water are typically treated by the addition of HBPA, followed by the addition of sodium bicarbonate (adjusting the pH to 6–8) and activate carbon, Er(III) ions could be efficiently removed from aqueous solution after about 30 min based on the cation-exchange and complexation-assisted precipitation method. Additionally, the removal of ultra trace amounts of Er(III) ions was not significantly affected by coexisting trace amounts of alkaline-earth metal ions (Mg2+, Ca2+ and Sr2+). HBPA is an effective Er(III) chelator, which may be a potential and promising alternative technique to remove Er(III) ions from aqueous solutions.

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“…The aqueous speciation of sodium oxalate is pH-dependent. ,,− At pH less than 2, sodium oxalate predominantly speciates as H 2 C 2 O 4 and Na + ions. At pH between 2 and 5, HC 2 O 4 – is the dominant complex species with a (−1) net ionic charge.…”

Section: Resultsmentioning

confidence: 99%

Effect of Adsorbed Carboxylates on the Dissolution of Boehmite Nanoplates in Highly Alkaline Solutions

Zhao,

Guo,

Xue

et al. 2024

Environ. Sci. Technol.

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Understanding the dissolution of boehmite in highly alkaline solutions is important to processing complex nuclear waste stored at the Hanford (WA) and Savannah River (SC) sites in the United States. Here, we report the adsorption of model carboxylates on boehmite nanoplates in alkaline solutions and their effects on boehmite dissolution in 3 M NaOH at 80 °C. Although expectedly lower than at circumneutral pH, adsorption of oxalate occurred at pH 13, with adsorption decreasing linearly to 3 M NaOH. Classical molecular dynamics simulations suggest that the adsorption of oxalate dianions onto the boehmite surface under high pH can occur through either inner-or outer-sphere complexation mechanisms depending on adsorption sites. However, both adsorption models indicate relatively weak binding, with an energy preference of 1.26 to 2.10 kcal/mol. By preloading boehmite nanoplates with oxalate or acetate, we observed suppression of dissolution rates by 23 or 10%, respectively, compared to pure solids. Scanning electron microscopy and transmission electron microscopy characterizations revealed no detectable difference in the morphologic evolution of the dissolving boehmite materials. We conclude that preadsorbed carboxylates can persist on boehmite surfaces, decreasing the density of dissolution-active sites and thereby adding extrinsic controls on dissolution rates.

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Multiple investigations of aqueous Eu(iii)–oxalate complexes: the reduction in coordination number and validation of spectral linear correlation

Abstract: Detailed information on the An(III) /Ln(III) complexation properties in solution is essential for separation chemistry and prediction of the potential for radionuclide migration from a nuclear waste repository into natural...

Cited by 7 publications

References 57 publications

Structural and spectroscopic studies of spontaneously formed crystalline Eu(iii)–aliphatic dicarboxylates at room temperature

Structural and spectroscopic studies of spontaneously formed crystalline Eu(iii)–aliphatic dicarboxylates at room temperature

Removal of Low Concentrations of Er(III) from Water Using Heptadecyl-1,1-bisphosphonic Acid

Effect of Adsorbed Carboxylates on the Dissolution of Boehmite Nanoplates in Highly Alkaline Solutions

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