Solubility of, and hydrogen ion adsorption on, some metal oxides in aqueous solutions to high temperatures
- Oak Ridge National Lab., TN (United States)
- Illinois State Water Survey, Champaign, IL (United States)
- Tohoku Univ., Sendai (Japan). Inst. of Mineralogy, Petrology and Economic Geology
- State Univ. of New York, Oswego, NY (United States). Dept. of Chemistry
Solubility of boehmite (AlOOH), ferrous hydroxide (Fe(OH)2)/magnetite (Fe3O4), zincite (ZnO), and brucite (Mg(OH)2) were measured over a range of temperatures (AlOOH, 100-290 C; Fe(OH)2/Fe3O4, 100-250 C; ZnO, 50-290 C; Mg(OH)2, 60-200 C) using in situ pH measurements. A hydrogen-electrode concentration cell was used; the pH range depended on the oxide. The solubility results for boehmite mainly demonstrate the method viability, while those for zincite are mainly restricted to mildly acidic to neutral pH where Zn{sup 2+} predominates in solution. The magnetite (presumably coated with Fe(OH)2) solubilities extend from pHs > 5 and, because of relevance to water/steam cycles of power plants, are compared in detail with previous studies. The same cell was used to investigate the surface adsorption-desorption thermodynamics of H ions on rutile (TiO2) and zincite to 290 C. Behavior of pH at zero-point-of-charge as function of temperature and application of the Stern-3-layer model were determined for this solid. The zincite study is still incomplete; preliminary results show trends that can be rationalized only qualitatively now with the zero- point-of-charge being apparently affected by hydration of the surface in basic solutions and specific adsorption of Na ions under the same conditions.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 521307
- Report Number(s):
- CONF-970623-1; ON: DE97008238
- Resource Relation:
- Conference: 5. international conference on cycle chemistry in fossil plants, Charlotte, NC (United States), 10-12 Jun 1997; Other Information: PBD: [1997]
- Country of Publication:
- United States
- Language:
- English
Similar Records
Solubility and Reaction Rates of Aluminum Solid Phases Under Hydrothermal Conditions
The solubility of zinc oxide in 0.03 m NaTr as a function of temperature, with in situ pH measurement