CO₂-selective poly (ether-block-amide)/polyethylene glycol composite blend membrane for CO₂ separation from gas...

Area of Science:

• Materials Science
• Chemical Engineering
• Polymer Science

Background:

• Composite blend membranes are crucial for gas separation applications.
• Poly(ether-block-amide) (Pebax-1657) is a promising polymer matrix for membrane technology.
• Incorporating additives like polyethylene glycol (PEG) can modify membrane properties.

Purpose of the Study:

• To investigate the effect of different molecular weights of polyethylene glycol (PEG) on the microstructure and gas separation performance of Pebax-1657 blend membranes.
• To evaluate the influence of PEG loading content on membrane properties.
• To identify optimal blend compositions for enhanced gas separation.

Main Methods:

• Preparation of composite blend membranes by incorporating PEG (PEG600, PEG1500, PEG4000) into a Pebax-1657 matrix at varying concentrations (10-40%wt.).
• Characterization of membrane microstructure and properties using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and water contact angle analysis.
• Evaluation of gas separation performance, including permeability and selectivity for various gases (N2, O2, CH4, CO2).

Main Results:

• Blending low molecular weight PEG (PEG600) into Pebax-1657 enhanced chain mobility, improved microstructure smoothness, and increased hydrophilicity.
• PEG600 incorporation significantly boosted the permeability of N2, O2, CH4, and CO2 with minimal impact on selectivity.
• Higher molecular weight PEGs (PEG1500, PEG4000) increased membrane crystallinity, reduced chain mobility, roughened the microstructure, and decreased hydrophilicity.
• The Pebax/40%PEG600 membrane achieved a CO2 permeability of 62.9 Barrer and selectivity of 83.8 for CO2/N2 separation.
• The Pebax/20%PEG600 membrane demonstrated a CO2 permeability of 63.12 Barrer and selectivity of 23.6 for CO2/CH4 separation.

Conclusions:

• Low molecular weight PEG (PEG600) is an effective additive for enhancing the gas separation performance of Pebax-1657 membranes.
• The optimized Pebax/PEG600 blend membranes show potential for efficient separation of gas mixtures like CO2/N2 and CO2/CH4.
• Membrane performance is strongly dependent on the molecular weight and loading of the incorporated PEG additive.