Statistical analysis of CO₂/N₂ gas separation permeance and selectivity using taguchi method

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Carbon dioxide (CO2) separation from industrial flue gases is critical for mitigating climate change.
• Membrane technology presents a viable and energy-efficient alternative to traditional gas separation methods.
• Polysulfone (PSF) membranes are widely investigated for gas separation due to their favorable properties.

Purpose of the Study:

• To investigate the effect of casting parameters on polysulfone membrane performance for CO2 separation.
• To optimize the fabrication process for enhanced CO2 permeance and CO2/N2 selectivity.
• To establish a correlation between casting conditions, membrane morphology, and separation performance.

Main Methods:

• Polysulfone (PSF) membranes were prepared via a dry-wet phase inversion technique using N-methyl-2-pyrrolidone (NMP) and tetrahydrofuran (THF).
• Casting parameters including PSF concentration, THF/NMP solvent ratio, and evaporation time were systematically varied.
• Scanning Electron Microscopy (SEM) was used for morphological characterization.
• Taguchi statistical analysis was employed to analyze experimental data and optimize performance metrics (CO2 permeance and CO2/N2 selectivity).

Main Results:

• The prepared membranes exhibited CO2 permeance ranging from 1.25 to 8.47 GPU and CO2/N2 selectivity between 2.95 and 8.92.
• Taguchi analysis revealed that PSF concentration had the most significant impact on membrane performance, followed by solvent ratio and evaporation time.
• The optimal casting parameters were determined as 20 wt% PSF concentration, a 17.5/82.5 THF/NMP ratio, and a 4-minute evaporation time.

Conclusions:

• The study successfully optimized polysulfone membrane fabrication for efficient CO2 separation.
• The findings highlight the critical role of casting parameters in tailoring membrane morphology and performance.
• The optimized membranes offer a promising solution for CO2 capture from flue gases.