Dissolution of Solid Particles in Liquids: A Shrinking Core Model

The dissolution of spherical particles in liquids is analyzed dynamically. Here, we consider the case the dissolution of solute yields a solute-free solid phase in the outer portion of a particle. As dissolution proceeds, the interface between the undissolved solid phase and the solute-free solid phase moves towards the center of the particle. We assume that there exist two resistances for the diffusion of solute molecules: the resistance due to the solute-free portion of the particle and that due to a surface layer near solid-liquid interface. In general, the equation governing the dynamic behavior of dissolution needs to be solved numerically. However, analytical expressions for the temporal variation of the size of the undissoved portion of a particle and the variation of dissolution time can be obtained in some special cases. The present analysis takes the effect of variable bulk solute concentration on dissolution into account.

• Wei-Lun Hsu
• Mon-Jyh Lin
• Jyh-Ping Hsu

• dissolution of particles
• surface layer
• shrinking core model
• dissolution time.

[1] M. R. Riazi and A. Faghri, "Solid dissolution with first-order chemical
reaction," Chem. Eng. Sci., vol. 40, pp. 1601-1603, 1985.
[2] A. N. Bhaskarwar, "On application of the method of kinetic invariants to
the description of dissolution accompanied by a chemical reaction,"
Chem. Eng. Commun., vol. 72, pp. 25-34, 1988.
[3] T. K. Sherwood, R. L. Pigford, and C. R. Wilke, Mass transfer. New
York: McGraw Hill, 1975.
[4] Y. W. Chen and P. J. Wang, "Dissolution of spherical solid particles in a
stagnant fluid: an analyticle solution," Can. J. Chem. Eng., vol. 67, pp.
870-872, 1989.
[5] E. M. Vidgorchik and A. B. Shein, Mathematical modeling of continuous
dissolution processes. Leningrad: Khimiye, 1971.
[6] K. A. Overhoff, J. D. Strom, B. Chen, B. D. Scherzer, T. E. Milner, K. P.
Johnston, and R. O. Williams, "Novel ultra-rapid freezing particle
engineering process for enhancement of dissolution rates of poorly
water-soluble drugs," Eur. J. Pharm.Biopharm., vol. 65, pp. 57-67, 2007.
[7] P. Loganathan, M. J. Hedley, M. R. Bretherton, and J. S. Rowarth,
"Accounting for particle movement when assessing the dissolution of
slow release fertilizers in field soils," Nut. Cycl. Agroecosyst., vol. 70, pp.
77-84, 2004.
[8] D. V. S. Gupta and R. E. Sparks, Controlled release of bioactive materials.
New York: Academic Press, 1980, pp. 189-212.