High-Performance Hybrid CMS Membranes Development via Synergistic Pore Tailoring and Sulfur-Doping

Area of Science:

• Materials Science
• Chemical Engineering
• Membrane Technology

Background:

• Optimizing the microstructure of hybrid carbon molecular sieve (HCMS) membranes is crucial for improving gas separation efficiency.
• Existing methods often struggle to achieve both high permeability and selectivity simultaneously.

Purpose of the Study:

• To investigate the use of methanesulfonic acid (MSA) as a porogen and dopant in HCMS membranes.
• To enhance CO2 separation performance by precisely controlling membrane microstructure and surface chemistry.

Main Methods:

• Incorporation of methanesulfonic acid (MSA) into CMS membranes during fabrication.
• Utilizing theoretical calculations to understand the effect of sulfur doping on pore environment affinity.
• Controlled carbonization of membranes to tune ultramicropore size distribution.

Main Results:

• The 6FDA-TMPD/MSA-5-500 HCMS membrane achieved ultra-high CO2 permeability (10557.6 Barrer) and CO2/CH4 selectivity (29.1), surpassing the Robeson upper bound.
• MSA-mediated cross-linking refined pore structure, reducing d-spacing and ultramicropore sizes.
• The 6FDA-TMPD/MSA-5-700 HCMS membrane exhibited excellent H2/CH4 selectivity (539.0) with high H2 permeability (2421.9 Barrer).

Conclusions:

• Methanesulfonic acid effectively acts as both a porogen and dopant, enabling precise control over HCMS membrane microstructure.
• This approach simultaneously modulates pore structure and surface chemistry, leading to superior gas separation performance.
• The study provides a novel strategy for developing high-performance HCMS membranes for various gas separation applications.