Vacuum seeding and secondary growth route to sodalite membrane

Synthesis of thin defect-free hydroxy sodalite membranes: New candidate for activated water permeation

“…The shortest synthesis duration reported is 45 min using microwave heating [29], however, the membranes produced are not free of defects since they show permeability towards hydrogen which is a bigger molecule (kinetic diameter 2.9Å) and in principle should not be able to permeate through hydroxy sodalite unless through defects. Other reports show similar results [28,46,47].…”

“…413 K carried for 3.5 h; the membrane has a thickness of 2 m. At longer synthesis times, the continuity of the membrane is lost and aggregates of crystals are instead formed on the surface. In comparison with the synthesis times given in literature on formation of hydroxy sodalite membranes [28,29,46,47], the synthesis time of 3.5 h found here is relatively short. The shortest synthesis duration reported is 45 min using microwave heating [29], however, the membranes produced are not free of defects since they show permeability towards hydrogen which is a bigger molecule (kinetic diameter 2.9Å) and in principle should not be able to permeate through hydroxy sodalite unless through defects.…”

“…While numerous studies have been performed in making and characterizing powder hydroxy sodalite, only few studies have reported the formation of hydroxy sodalite membranes, which are mostly by means of microwave heating [28,29] or through secondary growth formation [46,47]. Each of these methods has certain drawbacks, which leads to the formation of poor membranes.…”

Synthesis of nanostructure hydroxy sodalite composite membranes via hydrothermal method: support surface modification and synthesis method effects

“…This kind of zeolite has a six‐membered ring aperture with pore size of 0.28 nm, which makes them as interesting materials for separation of small molecules such as NH 3 (0.255 nm), water (0.265 nm), He (0.26 nm), and, depending on process conditions, H 2 (0.289 nm) from gas or liquid mixtures . Therefore, hydroxy sodalite zeolite membrane is expected to possess a better performance on the separation of small molecules from gas or liquid mixtures than the zeolite membranes with a bigger pore size . Hydroxy sodalite membrane has often been used as a water selective material for the separation of water from different organic basis .…”

“…Hydroxy sodalite membrane has often been used as a water selective material for the separation of water from different organic basis . Gas separation performance of the hydroxy sodalite zeolite membrane was mainly reported for He, and only a few works studied the performance of this kind of membrane in the separation of hydrogen where ideal selectivity of larger than 1000 was obtained for H 2 / n ‐C 4 H 10 at 0.1 MPa.…”