Steam permeation properties of perfluorosulfonic acid/ceramic composite membranes at a high temperature under various humidity conditions

The perfluorosulfonic acid (PFSA) polymer is an important materials for dehumidification membranes and is typically used at temperatures below 70 °C. In this study, the humid gas separation performances of PFSA membranes were evaluated at temperatures ranging from 80 to 200 °C under various relative humidity (RH) conditions to enable a wide potential range of applications at high temperatures, such as in steam recovery and dehydration membrane reactors. PFSA layers with 80 nm thicknesses were prepared on ceramic supports to achieve a high water permeance of the order of 10−6–10−5 mol/(m2 s Pa) and water/nitrogen permeance ratio ranged from several tens to 100 at temperatures ranging from 150 to 200 °C. This paper discusses the detailed effect of the RH on the permeation properties at 200 °C. The thickness of the PFSA layer is approximately the same as the water cluster size in the PFSA structure, leading to the unique permeation behavior. This study provides insights into the use of PFSA membranes at high temperatures under humid conditions.