Details
| Original language | English |
|---|---|
| Pages (from-to) | 28-40 |
| Number of pages | 13 |
| Journal | Analytical and Bioanalytical Chemistry |
| Volume | 383 |
| Issue number | 1 |
| Publication status | Published - 5 Jul 2005 |
| Externally published | Yes |
Abstract
The solubility of Zr(OH)4(am)-in other words hydrated Zr(IV) oxyhydroxide-is determined by means of coulometric titration (CT), and colloids are detected by laser-induced breakdown when the solubility limit is exceeded. Our results at pH 3-8 demonstrate that the solubility of Zr(OH)4(am) is several orders of magnitude higher than reported classical solubility data for acidic solutions, determined from undersaturation with a less soluble microcrystalline Zr(IV) oxide precipitate. Analysis of extended X-ray absorption fine structure (EXAFS) data shows that the microcrystalline colloids in a 0.1 mol l-1 Zr aqueous solution at pH 0.2 contain tetrameric units, similar to those present in the structure of ZrOCl2.8H2O. Characterization of the CT solutions by means of EXAFS shows that oligomeric species form as the solubility limit is approached. The current lack of data on equilibrium constants for polynuclear hydroxide complexes prohibits the use of a realistic speciation model to describe the solubility of pH-dependent Zr(OH)4(am). However, the solubility curve is obtained using the mononuclear hydrolysis constants estimated in the present paper, along with the solubility constant (logK′sp=-49.9±0.5 in 0.5 mol l -1 NaCl; logK°sp=-53.1±0.5 at I=0).
Keywords
- Colloids, EXAFS, Hydrolysis, LIBD, Zirconium
ASJC Scopus subject areas
- Chemistry(all)
- Analytical Chemistry
- Biochemistry, Genetics and Molecular Biology(all)
- Biochemistry
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In: Analytical and Bioanalytical Chemistry, Vol. 383, No. 1, 05.07.2005, p. 28-40.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Combined LIBD and XAFS investigation of the formation and structure of Zr(IV) colloids
AU - Cho, Hye Ryun
AU - Walther, Clemens
AU - Rothe, Jörg
AU - Neck, Volker
AU - Denecke, Melissa A.
AU - Dardenne, Kathy
AU - Fanghänel, Thomas
PY - 2005/7/5
Y1 - 2005/7/5
N2 - The solubility of Zr(OH)4(am)-in other words hydrated Zr(IV) oxyhydroxide-is determined by means of coulometric titration (CT), and colloids are detected by laser-induced breakdown when the solubility limit is exceeded. Our results at pH 3-8 demonstrate that the solubility of Zr(OH)4(am) is several orders of magnitude higher than reported classical solubility data for acidic solutions, determined from undersaturation with a less soluble microcrystalline Zr(IV) oxide precipitate. Analysis of extended X-ray absorption fine structure (EXAFS) data shows that the microcrystalline colloids in a 0.1 mol l-1 Zr aqueous solution at pH 0.2 contain tetrameric units, similar to those present in the structure of ZrOCl2.8H2O. Characterization of the CT solutions by means of EXAFS shows that oligomeric species form as the solubility limit is approached. The current lack of data on equilibrium constants for polynuclear hydroxide complexes prohibits the use of a realistic speciation model to describe the solubility of pH-dependent Zr(OH)4(am). However, the solubility curve is obtained using the mononuclear hydrolysis constants estimated in the present paper, along with the solubility constant (logK′sp=-49.9±0.5 in 0.5 mol l -1 NaCl; logK°sp=-53.1±0.5 at I=0).
AB - The solubility of Zr(OH)4(am)-in other words hydrated Zr(IV) oxyhydroxide-is determined by means of coulometric titration (CT), and colloids are detected by laser-induced breakdown when the solubility limit is exceeded. Our results at pH 3-8 demonstrate that the solubility of Zr(OH)4(am) is several orders of magnitude higher than reported classical solubility data for acidic solutions, determined from undersaturation with a less soluble microcrystalline Zr(IV) oxide precipitate. Analysis of extended X-ray absorption fine structure (EXAFS) data shows that the microcrystalline colloids in a 0.1 mol l-1 Zr aqueous solution at pH 0.2 contain tetrameric units, similar to those present in the structure of ZrOCl2.8H2O. Characterization of the CT solutions by means of EXAFS shows that oligomeric species form as the solubility limit is approached. The current lack of data on equilibrium constants for polynuclear hydroxide complexes prohibits the use of a realistic speciation model to describe the solubility of pH-dependent Zr(OH)4(am). However, the solubility curve is obtained using the mononuclear hydrolysis constants estimated in the present paper, along with the solubility constant (logK′sp=-49.9±0.5 in 0.5 mol l -1 NaCl; logK°sp=-53.1±0.5 at I=0).
KW - Colloids
KW - EXAFS
KW - Hydrolysis
KW - LIBD
KW - Zirconium
UR - http://www.scopus.com/inward/record.url?scp=27644565718&partnerID=8YFLogxK
U2 - 10.1007/s00216-005-3354-6
DO - 10.1007/s00216-005-3354-6
M3 - Article
C2 - 15997374
AN - SCOPUS:27644565718
VL - 383
SP - 28
EP - 40
JO - Analytical and Bioanalytical Chemistry
JF - Analytical and Bioanalytical Chemistry
SN - 1618-2642
IS - 1
ER -