The solubility of zinc oxide in 0.03 m NaTr as a function of temperature, with in situ pH measurement

Journal Article · Sat May 01 04:00:00 EDT 1999 · Geochimica et Cosmochimica Acta

DOI:https://doi.org/10.1016/S0016-7037(99)00109-X· OSTI ID:364122

Benezeth, P; Palmer, D A; Wesolowski, D J ^[1]

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1. Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.

The solubility of zincite (ZnO) has been measured in noncomplexing solutions over a wide range of pH{sub m} (4--11), and temperature (75--200 C) at 0.03 mol/kg ionic strength in NaTr media (sodium trifluoromethanesulfonate, a noncomplexing 1:1 electrolyte), in a hydrogen electrode concentration cell (HECC), which provided continuous in situ measurement of hydrogen ion molality. Total zinc content was analyzed by atomic absorption using graphite furnace, flame, and inductively coupled plasma (ICP) spectrometers. The direction of approach to the equilibrium saturation state was varied to demonstrate that the system was reversible thermodynamically. Separate experiments were performed in alkaline solutions (0.03 mol/kg NaOH) at 25 and 50 C in polypropylene syringes, and between 50 and 290 C in a Teflon-lined pressure vessel. The aim of these experiments was to reach higher pH{sub m} (>8 depending on the temperature) to determine the thermodynamic properties of the negatively charged species, Zn(OH){sub 3}{sup {minus}}. A least-squares regression of the results obtained at this ionic strength was used to determine the molal solubility products (Q{sub sn}) of zincite. The solubility products (Q{sub sn}) were extrapolated to infinite dilution (K{sub sn}), permitting calculation of the thermodynamic properties of aqueous species of zinc for comparison with previous work.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-96OR22464
• OSTI ID: 364122
• Journal Information: Geochimica et Cosmochimica Acta, Journal Name: Geochimica et Cosmochimica Acta Journal Issue: 10 Vol. 63; ISSN 0016-7037; ISSN GCACAK
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
54 ENVIRONMENTAL SCIENCES
ENVIRONMENTAL TRANSPORT
EXPERIMENTAL DATA
FLUORINATED ALIPHATIC HYDROCARBONS
PH VALUE
SODIUM COMPOUNDS
SOLUBILITY
SOLVENT PROPERTIES
SULFONATES
THERMODYNAMIC PROPERTIES
ZINC OXIDES