Positively Charged Polymer-Brush MOFs for Large-Area, Pressure-Resistant Gas Separation Membranes.

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Scalable fabrication of high-performance gas separation membranes is critical for energy-efficient gas purification.
• Industrial adoption of mixed matrix membranes (MMMs) is hindered by nanofiller dispersion instability during manufacturing, causing aggregation and defects.

Purpose of the Study:

• To develop a universal strategy for stabilizing nanofillers in membranes for scalable, high-performance gas separation.
• To enable industrial translation of pressure-resistant mixed matrix composite membranes (MMCMs) with tunable performance.

Main Methods:

• A "pre-occupation and post-activation" strategy was used to create positively charged polymer-brush metal-organic frameworks (MOFs).
• This method employs electro-steric effects and hydrogen-bonding for dual stabilization of fillers during static and dynamic processing.
• Roll-to-roll production was utilized to fabricate 1 m-wide MMCMs.

Main Results:

• The strategy ensured stable nanofiller dispersion and seamless integration into ultrathin selective layers.
• The resulting MMCMs demonstrated tunable and outstanding CO2/CH4 and CO2/N2 separation performance under relevant industrial pressures.
• Membrane area requirements were reduced by over an order of magnitude compared to lab-scale membranes.

Conclusions:

• The developed strategy overcomes key processing barriers in MMM fabrication.
• This work represents a significant advancement toward the industrial implementation of MOF-based membranes for energy-efficient gas separation.
• Scalability and operational robustness were validated through large-scale production and module testing.