Abstract The development of ceramic membranes for the most diverse separation processes has gained high visibility, mainly due to their better performance in harsh environments in comparison to polymeric materials. Among the different techniques used to prepare tubular ceramic membranes, the centrifugal casting (CC) is interesting for obtaining highly homogeneous structures, essential for gas separations. This study assessed the influence of two sintering temperatures (1450 and 1500 °C) of alumina membranes prepared by CC on the membrane morphology and on the permeation of helium, nitrogen and oxygen gases. The membranes were characterized by their morphology, apparent porosity, and gas permeation. The results indicated that the sintering temperature is a fundamental parameter for controlling membrane properties, an increase of only 50 °C led to a tenfold decrease in the gas permeate flux, indicating densification of membrane porous structure. This was in accordance with the results observed in the membrane micrographs and the apparent porosity.

The separation of olefin/paraffin mixtures is one of the most important processes of the chemical industry. This separation is typically carried out by distillation, which is an energy and capital intensive process. One promising alternative is the use of facilitated transport membranes, which contain specific carrier agents in the polymer matrix that interact reversibly with the double bond in the olefin molecule, promoting the simultaneous increase of its permeability and selectivity. In this study, polyurethane (PU) membranes were prepared using two different silver salts (triflate and hexafluorantimonate). The membranes were structurally characterized and their performance for the separation of propylene/propane mixtures was evaluated. The results of the characterization analyses indicated that the triflate salt was the most efficient carrier agent. The membranes containing this salt showed the best performance, reaching an ideal selectivity of 10 and propylene permeability of 188 Barrer.