Preparation and optimization of mordenite nanocrystal-layered membrane for dehydration by pervaporation

• Mordenite nanocrystal-layered membrane was successfully prepared.
• Water permeance was almost the same regardless of coexisting organic compound.
• Crystal size in protection layer could be controlled by pre-aging and hydrothermal synthesis condition.
• The protection layer consists of smaller crystal showed higher water flux.

Mordenite nanocrystal-layered membranes consisting of a mordenite nanocrystal layer and protection layer were successfully prepared. The obtained mordenite membranes were applied to the separation of water from water/organic solutions (organic solvents: ethanol, acetone, iso-propanol, or acetic acid) using a pervaporation method at temperatures from 60 to 100 °C. Water permeance through the mordenite membrane in each water/organic solution system was almost identical regardless of organic solvent types in the feed solution. In contrast, the permeance of the organic molecules depended on their polarities. The pre-aging temperature of the mother liquid and the heating rate for formation of the protection layer affected the secondary growth process that formed the protection layer, leading to different morphologies and sizes of the crystals in the protection layer. Water flux increased with decreasing crystal size in the protection layer because the number of non-zeolitic pores among the mordenite crystal increased as the crystal size decreased.

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