Silicone modified silica membrane. Application to the gas separation

Abstract The purpose of this work is to enhance the performance of ceramic membranes with large porosity. This objective can be get both by a controlled reduction of pore diameter and/or, by a controlled modification of the surface of the upper layer of the ceramic membrane. A typical modification is a thin film deposition using hybrid material prepared from TiO 2 –SiO 2 and silicone (poly-dimethyl-siloxane) using the sol–gel technique. The aging time of the initial solution is an important parameter for the elaboration of efficient silica membranes. The SEM observation of the deposited thin films shows a formation of rather homogeneous spheres of mean diameter of about 1 μm. These spheres are supporting a top thin ‘silicone layer’ when the aging time ( t ag ) is under 20 h but are without any top thin film when t ag is higher than 24 h. Gas flows measurements were done using C 3 H 8 , N 2 , He and CO 2 gases. The best membranes in terms of permeability/selectivity are ones obtained with a t ag of about 48 h. The silicone–silica membrane was also tested with alkane gases and the efficiency for alkanes gas separation deduced.