Improved Ti-silicate umbite membranes for the separation of H2

Microporous titanosilicate (K2TiSi3O9H2O) with an umbite structure has been reproducibly prepared as 5-μm-thick continuous membranes on asymmetric TiO2 tubular supports by seeded hydrothermal synthesis. These membranes were able to separate H2 from N2 with good selectivity even in the presence of moisture, unlike other microporous zeolitic hydrophilic membranes where capillary condensation strongly hinders gas permeation. The average H2/N2 separation selectivity calculated for five Ti-umbite membranes obtained in the same synthesis conditions (200 °C, 48 h) was 45.2 ± 3.8 (together with an average H2 permeance of 4.6 ± 1.1 × 10−9 mol/(m2 s Pa).