Membranes céramiques à base d’argiles, d’amidon de manioc et d’os de bovins : élaboration, caractérisation et utilisation dans la filtration des eaux

Abstract

This work aims to produce and characterize ceramics membranes applied to water filtration. Materials and ceramics products mineralogy are obtained by XRD. Their thermal behavior is obtained by TGA/DSC analysis, dilatometry and thermal conductivity. Ceramics physicochemical and mechanical properties are obtained by Archimède’s method (porosity), BET specific surface, SEM, chemical corrosion test and flexural strength. Clays mineralogy and XRF show that they are in majority constituted by silicic and aluminic oxides (SiO2 + Al2O3 = 80.76% for MY3 and 78.29 % for KG), kaolinite (75.61%) for MY3, kaolinite (50%) and quartz (29%) for KG. AM is essentially constituted by organic matter. OB is constituted by 54.65% of CaO and 40.24% of P2O5, essentially by hydroxyapatite.Testing membranes porosities are higher with AM and decreases with temperature raising. They vary from 32% at 56%. High densification and flexural strength at 1150°C have permitted to conclude that this temperature is ideal for ameliorated membranes production. These supports are essentially constituted by macropores with size less than 0.23 µm and corrosion rate <7%. Isotropics membranes has been produced at 1150°C. Their porosities are included between 30% and 45%, and their structure is constituted by macro and mesopores of which size are from 0.01 µm to 0.37 µm. Permeability are in function of membranes and varies from 108 L/h.m2 .bar to 2198 L/h.m2.bar. Flexural strength vary from 7 MPa (SM3) to 11 MPa (SM2), specifics surfaces area and thermal conductivities are low (respectively 0.92 m2/g to 1.64 m2/g and 0.40 W.m-1.K-1to 0.54 W.m-1.K-1). Water filtration gives higher turbidity reduction. Except CM04 filtrated water which have a turbidity high than 1 NTU, the one of others filtrated water is low than 1 NTU. pH results show that isotropics and testing membranes contributed to pH regulation. Without any external pressure, any organism living or not whose size is > 2 nm wasretained by membrane during filtration. These isotropic membranes are therefore adapted to the elimination of virus, pigments, some colloids, bacteria and coarse particles; because these microorganisms and particles sizes are higher than 2 nm. These membranes can be efficiently cleaned by manual washing with a sponge, when no mechanical pressure is applied during filtration.