Processing, structural characterization and performance of alumina supports used in ceramic membranes

Although there are various commercially available methods for the separation and capture of gas species such as CO2 and H2, they are energy expensive and in some cases environmentally unfriendly. The membrane separation process presents advantages such as its relative simplicity, ease of use, low energy consumption, and application in the separation of both liquid and gas mixtures. For these reasons, the membrane technology has achieved in the last years a great commercial and strategic importance. In this work we present a structural characterization of an alumina support, before and after the deposition of a titania film on its surface. The obtained asymmetric membranes are intended to be used in gas separation processes. The alumina supports and titania coatings were prepared by dry-pressing and sol–gel process, respectively. The processed samples were characterized by X-ray diffraction (XRD), nitrogen sorption, scanning electron microscopy (SEM), and X-ray microtomography (μ-CT). In order to evaluate the membranes performance, single-gas permeation experiments were performed at room temperature with nitrogen, helium, and carbon dioxide. We observed that although the alumina supports obtained in this work have not been submitted to any surface finishing procedure, the obtained membranes have potential application in gas separation processes. We observed that increasing the pressure feed leads to improving their separation capacity.