Aluminum speciation and equilibria in aqueous solution: III. Potentiometric determination of the first hydrolysis constant of aluminum(III) in sodium chloride solutions to 125[degrees]C
- Oak Ridge National Lab., TN (United States)
The first molal hydrolysis quotient of aluminum(III) was measured potentiometrically from 25 to 125[degrees]C at 25[degrees] intervals at ionic strengths of 0.1, 0.3, 1.0, and 5 mol[center dot]kg[sup [minus]1] with sodium chloride as the supporting electrolyte. The experimental method involved using a hydrogen-electrode concentration cell modified to compensate for any intrinsic potential offset between the two electrodes. The initial concentration of Al[sup 3+] was varied to test for the presence of multinuclear aluminum species while being kept to a maximum of 10[sup [minus]3] mol[center dot]kg[sup [minus]1] to minimize their occurrence. Similarly, the maximum degree of hydrolysis of Al[sup 3+] reached in each titration was ca. 30%, after which polymerization and/or precipitation became apparent. The equilibrium quotients obtained in this study and selected values from the literature were fitted by an empirical equation incorporating a linear dependence of log K[sub 1,1] on the reciprocal temperature (Kelvins) over the range 10--200[degrees]C and three ionic-strength-dependent parameters. Comparisons are made between the results of this study and the literature values. 42 refs., 5 figs., 5 tabs.
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6260418
- Journal Information:
- Geochimica et Cosmochimica Acta; (United States), Vol. 57:13; ISSN 0016-7037
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM
HYDROLYSIS
AQUEOUS SOLUTIONS
EQUILIBRIUM
ALUMINIUM IONS
POTENTIOMETRY
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
THERMODYNAMIC PROPERTIES
CHARGED PARTICLES
CHEMICAL REACTIONS
DECOMPOSITION
DISPERSIONS
ELEMENTS
IONS
LYSIS
METALS
MIXTURES
PHYSICAL PROPERTIES
SOLUTIONS
SOLVOLYSIS
TEMPERATURE RANGE
TITRATION
400201* - Chemical & Physicochemical Properties