Supported SOD membrane with steam selectivity by a two-step repeated hydrothermal synthesis

- Seeding was not successful for SOD membrane preparation on alumina supports.
- A two-step repeated hydrothermal synthesis for SOD membrane has been developed.
- For the first time, steam/gas separations on SOD membranes are reported.
- Separation factors H2O/H2, H2O/CH4, and H2O/CO2 are 4.6, 14.5 and 22.6 at 200 °C.