Abstract
Surface titrations were carried out on suspensions of monoclinic ZrO 2 from 25 to 290∈°C slightly above saturation vapor pressure at ionic strengths of 0.03, 0.1 and 1.0 mol · kg-1(NaCl). A typical increase in surface charge was observed with increasing temperature. There was no correlation between the radius of the cations, Li+, Na+, K+ and (CH3)4N+, and the magnitude of their association with the surface. The combined results were treated with a 1-pKa MUSIC model, which yielded association constants for the cations (and chloride ion at low pH) at each temperature. The pH of zero-point-charge, pHzpc, decreased with increasing temperature as found for other metal oxides, reaching an apparent minimum value of 4.1 by 250∈°C. Batch experiments were performed to monitor the concentration of LiOH in solutions containing suspended ZrO2 particles from 200 to 360∈°C. At 350 and 360∈°C, Li+ and OH- ions were almost totally adsorbed when the pressure was lowered to near saturation vapor pressure. This reversible trend has implications not only to pressure-water reactor, PWR, operations, but is also of general scientific and other applied interest. Additional experiments probed the feasibility that boric acid/borate ions adsorb reversibly onto ZrO2 surfaces at near-neutral pH conditions as indicated in earlier publications.
Original language | English (US) |
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Pages (from-to) | 907-924 |
Number of pages | 18 |
Journal | Journal of Solution Chemistry |
Volume | 38 |
Issue number | 7 |
DOIs | |
State | Published - Jul 2009 |
Externally published | Yes |
Keywords
- Adsorption
- Batch experiments
- Borate anions
- High temperature
- Lithium ions
- MUSIC model
- PWR applications
- Potentiometry
- Zirconium oxide
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology
- Physical and Theoretical Chemistry