Organic Structure-directing Agent-free Synthesis for *BEA-type Zeolite Membrane

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Membrane separation is a key energy-saving technology.
• Zeolite membranes offer excellent thermal, chemical, and mechanical stability for hydrocarbon separations.
• BEA-type zeolites are promising due to their large pores and tunable Si/Al ratio.

Purpose of the Study:

• To develop an organic structure-directing agent (OSDA)-free protocol for *BEA zeolite membrane preparation.
• To investigate the impact of seed preparation and dip-coating on membrane quality.
• To achieve defect-free *BEA membranes for efficient separation processes.

Main Methods:

• A four-step protocol: support pretreatment, seed preparation, dip-coating, and membrane crystallization.
• Preparation of *BEA seed crystals using conventional hydrothermal synthesis with OSDA.
• Loading seed crystals onto an α-Al2O3 support via dip-coating.
• Secondary growth crystallization via hydrothermal treatment at 393 K for 7 days without OSDA.

Main Results:

• Successful preparation of a *BEA zeolite membrane with significantly reduced defects.
• Demonstration that seed preparation and dip-coating are critical factors influencing membrane quality.
• A viable OSDA-free secondary growth method for *BEA membrane fabrication.

Conclusions:

• The developed protocol provides a pathway for fabricating high-quality, OSDA-free *BEA zeolite membranes.
• Optimizing seed preparation and dip-coating is essential for defect-free membrane formation.
• These membranes hold potential for energy-efficient hydrocarbon separations in the petrochemical industry.