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Thermodynamic description of Be(II) solubility and hydrolysis in acidic to hyperalkaline NaCl and KCl solutions

Çevirim-Papaioannou, N. ORCID iD icon 1; Gaona, X. ORCID iD icon 1; Böttle, M. 1; Bethune, E. Y. 1; Schild, D. ORCID iD icon 1; Adam, C. 1; Sittel, T. ORCID iD icon 1; Altmaier, M. ORCID iD icon 1
1 Institut für Nukleare Entsorgung (INE), Karlsruher Institut für Technologie (KIT)


The solubility of Be(II) is investigated in carbonate-free dilute to concentrated HCl–NaCl–NaOH, KCl–KOH, NaOH and KOH solutions. Undersaturation experiments were performed under Ar atmosphere at T= (22 ± 2) °C. XRD, XPS, SEM and quantitative chemical analysis confirm that α-Be(OH)$_{2}$(cr) is the solid phase controlling the solubility in all evaluated systems. No transformation of α-Be(OH)$_{2}$(cr) to β-Be(OH)$_{2}$(cr) or ternary solid phases Na/K–Be(II)–OH(s) is observed in the investigated systems within the timeframe of this study (t ≤ 600 days). An amphoteric solubility behaviour of Be(II) is observed with a solubility minimum at pH$_{m}$ ≈ 9.5 (with [Be(II)] ≈ 10$^{-6.8}$M), regardless of the ionic strength. The combination of solubility data determined in acidic pH$_{m}$ conditions and the hydrolysis scheme reported in the literature for cationic hydrolysis species of Be(II) is used for the determination of the solubility constant of α-Be(OH)$_{2}$(cr), log *K°$_{s,0}$ = (6.9 ± 0.4). Slope analysis of the solubility data in alkaline to hyperalkaline conditions and $^{9}$Be NMR support the predominance of the monomeric hydrolysis species Be(OH)$_{2}$(aq), Be(OH)$_{3}$– and Be(OH)$_{4}$$^{2-}$ within the strongly alkaline pH$_{m}$-conditions relevant in cementitious systems. ... mehr

Postprint §
DOI: 10.5445/IR/1000120378
Veröffentlicht am 10.03.2023
DOI: 10.1016/j.apgeochem.2020.104601
Zitationen: 9
Zitationen: 12
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Nukleare Entsorgung (INE)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 0883-2927, 1872-9134
KITopen-ID: 1000120378
HGF-Programm 32.01.01 (POF III, LK 01) Grundl. Unters. - Geochemie v. Actiniden
Weitere HGF-Programme 32.11.03 (POF IV, LK 01) Fundamental Scientific Aspects
Erschienen in Applied geochemistry
Verlag Elsevier
Band 117
Seiten Article: 104601
Nachgewiesen in Scopus
Web of Science
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