2025 AIChE Annual Meeting

(629a) Thin Film Composite Membranes for Scale-up of H2-Stable Ag+-Based Facilitated Transport Membranes

Authors

Matthew Davenport, University of Texas at Austin
Joan F. Brennecke, The University of Texas At Austin
Benny D. Freeman, The University of Texas at Austin
Olefin and paraffin separation remains a critical challenge in petrochemical processing due to their similar physicochemical properties. This research investigates thin-film composite (TFC) membranes incorporating high silver ion (Ag⁺) loading in polyethylene oxide (PEO) polymer matrices to facilitate selective olefin transport via facilitated transport mechanisms. To address the solubility issue of crosslinked PEO, high molecular weight PEO was successfully synthesized using thermal polymerization. Ultrathin selective layers (<1µm) were successfully fabricated, enabling detailed evaluation of membrane performance as a function of selective layer thickness and silver salt loading. Experimental results revealed that reduced membrane thickness correlates with diminished olefin/paraffin selectivity. The GIWAXS illustrates increased amorphous structure formation and reaction rate limitations associated with Ag⁺-olefin complexation in the thinner selective layer. Optimal membrane performance was identified at an 80 mass% silver salt concentration, offering the highest balance of permeance (C2H4: 9 GPU, C3H6: 15 GPU) and selectivity (C2H4/C2H6=30, C3H6/C3H8=200). More important thing is the membranes demonstrate 100 hour stability test under 2bar H2, which is a common contaminate poisoning Ag+-based facility transport membranes. These advances provide promising avenues for energy-efficient, industrial-scale olefin/paraffin separations.