Synthesis and characterization of inorganic membranes and applications

The development of membranary technologies had introduced the membrane mineral which are prepared from ceramic materials, they offer many potential advantages over commercial organic polymer membranes for separation processes. Inorganic membranes are very resistant to a wide variety of solvents and are quite stable at hard operating conditions. These features have attracted a great deal of attention from the standpoint of membrane applications. Among the methods of preparation developed, the sol-gel process is appropriate to elaborate thin and porous layers with controllable porosity. The synthesis of gel is based on hydrolysis-condensation reactions indirectly to form a veritable lattice of oxide from molecular precursors. The hydrolysis reaction must be controlled to avoid precipitation of hydrous metal oxide. A true oxide network is formed by chemical bonds in the solution. The deposit thin layers has been realized with a sol prepared with the polymerization of molecular units. The control of sol-gel transition and thermal decomposition has allowed us the synthesis of the mixed oxide ZrO2-SiO2. These results show the great potentiallity of inorganic membrane and allow new applications to be taken into account particulary waste water treatment and gas separation. Crossflow microfiltration and ultrafiltration are becoming of increasing interest to produce drinking water. They can remove bacteria and clarify the water in a single step, so they can reduce appreciably the classic sequences of treatment processes. The structural characterization was studied by differential thermal analysis, infrared spectroscopy, X-ray diffraction and the textural characterization by nitrogen adsorption-desorption allowed us to observe the variation of the surface area, porous volume and pore diameters according to temperature. Scanning electron microscopy observation showed homogeneous layers without cracking. In this paper, some experimental results on the synthesis and characterization of inorganic membrane will be presented.