Green chemistry-based fabrication of hollow fiber and flat sheet polyimide membranes for CO2/CH4 separation

In this work, the successful fabrication of polymeric hollow fiber (HF) and flat sheet (FS) membranes was examined by employing γ-butyrolactone (GBL)-a green and environmentally friendly solvent- for the polymer's dissolution following the principles of green chemistry and sustainability regarding the membrane preparation. In addition, the ternary phase diagram of the P84/GBL/water was constructed and the viscosity of dope solution was measured for different concentrations and temperatures. Their morphological characteristics of the prepared polyimide membranes were investigated through SEM analysis. CO₂/CH₄ separation measurements under continuous flow were performed to evaluate the efficiency of the membranes for a binary 10/90 vol.% CO₂/CH₄ gas mixture. The developed green HF and FS membranes exhibited comparable, and in some cases even superior, performance compared to membranes prepared using the conventional and highly toxic NMP solvent, making them highly promising candidates for CO₂/CH₄ separation, with a real mixture separation factor of ∼58.