Elaboration and characterisation of fly ash based mineral supports for microfiltration and ultrafiltration membranes

The development and the characterisation of a new support for microfiltration and ultrafiltration membranes from fly ash applied to filtration are presented. The choice of this material is based primarily on its low cost (as fly ash is produced abundantly as a solid waste by coal fired power plants in many parts of the world). The support, with tubular configuration, was prepared from fly ash which was obtained by the sintering of non-grinded mineral coal at 800 °C. The resulting powder, mixed with organic additives and water, could be extruded to elaborate a porous structure. The firing temperature of the support is 1125 °C. The morphology of the surface and the cross-section observed on scanning electron microscope (SEM) are homogeneous and do not present any macrodefects (cracks, etc.). The mean pore diameter, measured by mercury porosimetry is 4.5 μm and the pore volume is 51%. The tubes display a good mechanical and chemical resistance that allow to use them as supports for tangential micro- and ultrafiltration processes.