Poly[3-ethyl-1-vinyl-imidazolium] diethyl phosphate/Pebax^® 1657 Composite Membranes and Their Gas Separation...

Area of Science:

• Materials Science
• Polymer Chemistry
• Chemical Engineering

Background:

• Poly(ionic liquid)s (PILs) offer potential for gas separation but require improved stability and mechanical strength.
• Block copolymers like Pebax® 1657 can provide mechanical support, but their gas separation performance needs enhancement.

Purpose of the Study:

• To investigate the effect of blending poly[3-ethyl-1-vinyl-imidazolium] diethyl phosphate (PEVI-DEP) with Pebax® 1657 on composite membrane properties.
• To evaluate the gas transport and separation performance of these novel composite membranes.

Main Methods:

• Composite membranes were prepared by blending Pebax® 1657 with varying wt.% of PEVI-DEP (20, 40, 60 wt.%).
• Membrane morphology was analyzed using scanning electron microscopy (SEM).
• Gas transport properties were assessed via time-lag and gravimetric sorption measurements.

Main Results:

• PEVI-DEP content influenced membrane morphology and gas transport.
• CO2 solubility in the membranes was not significantly affected by PEVI-DEP addition.
• A 40 wt.% PEVI-DEP blend showed over 50% improvement in permeability and selectivity for H2/CH4 and H2/CO2 separations, but higher concentrations decreased performance.

Conclusions:

• Blending Pebax® 1657 with PEVI-DEP can enhance selectivity and permeability for specific light gas separations.
• The optimal PEVI-DEP concentration is crucial for maximizing performance, with higher amounts leading to detrimental effects.
• These composite membranes show promise for industrial gas separation applications, particularly for H2-based mixtures.