Static state synthesis of STT zeolite membranes for high-pressure H2/CH4 separation

STT zeolite membrane with seven-membered rings (7 MR) and nine-membered rings (9 MR) is an ideal alternative for the separation of hydrogen (H 2 ) and methane (CH 4 ). However, the successful synthesis is only possible in rotation conditions, which is difficult to achieve at an industrial scale. Herein we developed a static synthesis approach to prepare high-quality STT zeolite membranes. The precursor transformed in-situ from a liquid state to a semi-solid state to efficiently suppress the nucleation in the bulk gel. This did not affect the growth of the seed layer to form a continuous membrane. The water content was modulated between y  = 44 and y  = 124 in the molar composition of 1 SiO 2 : 0.2 TMAdaOH: y H 2 O. The precursor could be re-used one more time to reduce the total amount of chemical waste. The optimal H 2 permeance and H 2 /CH 4 mixture selectivity was up to 6.1 × 10 −8  mol m −2  s −1  Pa −1 and 115 at atm pressure. The H 2 permeation flux monotonically increased to 2.0 Nm 3  m −2  h −1 under feed pressure up to 2.1 MPa. This paves the way for zeolite membranes to high-pressure H 2 separation in practical applications.