Study of dissolution kinetics of K₂SO₄ crystal in aqueous ethanol solutions with a statistical rate theory

Dissolution kinetics of K₂SO₄ crystal in aqueous ethanol solutions was studied on-line with ion selective electrode. The concentration of K₂SO₄ was calculated from the determined electromotive force in which the activity coefficient of components in the liquid phase was calculated with the Pitzer equation. Dissolution kinetic parameters in the modified statistical rate theory were regressed. The correlation results show that dissolution rate of K₂SO₄ is slower in aqueous ethanol solutions than that in aqueous solutions. The two most important reasons are as follows: (1) The solubility of K₂SO₄ in aqueous ethanol solutions is lower than that in aqueous solutions, which causes a decrease of the driving force of mass transfer. (2) The process of surface reaction of K₂SO₄ became slower due to the addition of ethanol, so that the whole process is mainly dominated by the surface reaction instead of mass transfer.