Vogelsberger W, Schmidt J (2011)
Publication Status: Published
Publication Type: Journal article, Original article
Publication year: 2011
Publisher: AMER CHEMICAL SOC
Book Volume: 115
Pages Range: 1388-1397
Journal Issue: 5
DOI: 10.1021/jp105993t
Dissolution experiments are carried out with nanoparticles of barium sulfate in water. An unusual concentration-time behavior is observed. A concentration maximum is measured at the very beginning of the dissolution process. This maximum considerably exceeds the saturation concentration of bulk material. The maximum concentration is followed in time by a decrease of the g concentration until the saturation concentration of the bulk material is obtained. This behavior is called kinetic size effect and it is a characteristic of nanoscale particles in general. The colloidal system can be modeled theoretically by thermodynamic and kinetic considerations that cover all processes which may occur in the system: nucleation, particle growth, Ostwald ripening, and dissolution of particles. It has been shown that only the outer surface of the particles is responsible for the dissolution kinetics; it is suggested that the surface of micropores yields no contribution. The dissolution curves observed experimentally follow from the model considerations. It is possible by comparison of experiment and theory to estimate the saturation concentration influenced by the ionic strength in the solution. This effect can be well described by the extended Debye-Huckel law. The measured numerical values of the saturation concentrations are found to be in the range of 4-14 mu mol L-1 and therefore in the vicinity of the solubility product of BaSO4. The saturation activity at infinite dilution (I -> 0) is a(Bn)(infinity) = 2.43 +/- 0.12 mu mol L-1 and the thermodynamic solubility product is K-L(infinity) = 10(-11.23). Furthermore, the model calculations provide the possibility to estimate the interfacial tension of the system nanopartide - solution. The numerical value of 1.1 N m(-1) is obtained. The error of the estimated interfacial tension is approximately as large as about 15%. This seems to be acceptable in view of a lack of reliable data in the literature. It is possible furthermore to calculate a kinetic rate constant for any changes that may occur in the colloidal system. The error of this rate constant, however, may be as large as a factor of 10.
APA:
Vogelsberger, W., & Schmidt, J. (2011). Studies of the Solubility of BaSO4 Nanoparticles in Water: Kinetic Size Effect, Solubility Product, and Influence of Microporosity. Journal of Physical Chemistry C, 115(5), 1388-1397. https://dx.doi.org/10.1021/jp105993t
MLA:
Vogelsberger, Wolfram, and Jochen Schmidt. "Studies of the Solubility of BaSO4 Nanoparticles in Water: Kinetic Size Effect, Solubility Product, and Influence of Microporosity." Journal of Physical Chemistry C 115.5 (2011): 1388-1397.
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