A modified method for determination of diffusivities of low molecular substances in non-Newtonian liquids

A modified method for determination of diffusivities of low molecular substances in non-Newtonian liquids described by the power-law model has been proposed. It is based on the dissolution of Geiss body, with a parameter m=1/3 rotating in an infinite fluid. In this case, the solution of the differential equations of motion and mass transfer is available as an analytical formula for calculating the diffusivity coefficient.The method allows the extension of the variety of media and diffusing species. It has been illustrated with dissolving of gypsum in water and five non-Newtonian liquids. The results obtained have been interpreted taking into account the interaction between calcium ions and polymer molecules of the non-Newtonian system, as well as the heterogeneity of the system near to the dissolving surface.