Ultrathin porous amine-based solid adsorbent incorporated zeolitic imidazolate framework-8 membrane for gas...

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Continuous gas separation is crucial for industrial processes.
• Traditional solid adsorbents often require regeneration, limiting continuous operation.
• Zeolitic imidazolate framework-8 (ZIF-8) membranes show promise for gas separation but can have defects.

Purpose of the Study:

• To develop a novel, continuously operable gas separation system.
• To enhance the fabrication and performance of ZIF-8 membranes.
• To leverage amine-based adsorbents for improved gas selectivity and membrane integrity.

Main Methods:

• Fabrication of an amine-based solid adsorbent using ZIF-8, 3-isocyanatopropyltrimethoxysilane (IPTMS), and N-[(3-trimethoxysilyl)propyl]diethylenetriamine (3N-APS).
• Incorporation of the amine-based adsorbent during the in-situ growth of ZIF-8 membranes on a macroporous substrate.
• Characterization of the resulting composite membrane's gas separation performance (CO2/N2, CO2/CH4, H2/CH4).

Main Results:

• The integrated ZIF-8 membrane exhibited excellent CO2/N2 and CO2/CH4 separation performance.
• An ultrathin (0.6 μm) ZIF-8 membrane achieved a high CO2 permeance (4.75 × 10^-6 mol m^-2 s^-1 Pa^-1) with selectivities of 4.67 for CO2/N2 and 6.02 for CO2/CH4.
• The membrane demonstrated superior H2/CH4 selectivity (31.2) and high H2 permeance (2.45 × 10^-5 mol m^-2 s^-1 Pa^-1).

Conclusions:

• Combining amine-based adsorbents with ZIF-8 membranes offers a viable strategy for continuous gas separation.
• The amino groups in the adsorbent facilitate ZIF-8 nucleation and growth, improving membrane quality.
• This novel composite membrane system shows significant potential for efficient industrial gas separations.