Holographic interferometry study of the dissolution and diffusion of gypsum in water

Jean Colombani (1) , Jacques Bert (1)

1 LPMCN - Laboratoire de Physique de la Matière Condensée et Nanostructures

We have performed holographic interferometry measurements of the dissolution of the (010) plane of a cleaved gypsum single crystal in pure water. These experiments have provided the value of the dissolution rate constant k of gypsum in water and the value of the interdiffusion coefficient D of its aqueous species in water. D is 1.0 x 10^-9 m2 s^-1, a value close to the theoretical value generally used in dissolution studies. k is 4 x 10^-5 mol m^-2 s^-1. It directly characterizes the microscopic transfer rate at the solid-liquid interface, and is not an averaged value deduced from quantities measured far from the surface as in macroscopic dissolution experiments. It is found to be two times lower than the value obtained from macroscopic experiments.

Mots clés: dissolution; holographic interferometry; gypsum; diffusion

Domaines: Géochimie; Dynamique des Fluides [physics.flu-dyn]; Milieux et Changements globaux

Jean Colombani, Jacques Bert. Holographic interferometry study of the dissolution and diffusion of gypsum in water. Geochimica et Cosmochimica Acta, 2007, 71, pp.1913-1920. ⟨10.1016/j.gca.2007.01.012⟩. ⟨hal-00432680⟩