Physico-Chemical Study of Coating Formulation Based on Natural Apatite for the Elaboration of Microfiltration Membrane

Abstract

This work deals with the experimental characterization of the rheological properties of a dip solution which will be used to elaborate a new apatite/clay microfiltration membrane by deposition using slip casting process of the active layer on a tubular support based on natural clay previously prepared.

So, the rheological study of various coatings with different concentration of apatite powder, polyvinyl alcohol (PVA) and water under different conditions regarding temperature and stirring time was done. It was found that the suitable suspension should follow a rheo- thickner behavior having a viscosity in the range of 30-35 mPa s at room temperature of 25 to 30°C. The optimum conditions then found to achieve these properties were: a suspension of 4% of apatite, 40% of PVA stirred for 180minutes. The study reveals also that the thickness of the active membrane layer depends on the coating time.