(491d) Ultra-Selective Defect-Free Interfacially Polymerized Molecular Sieve Thin-Film Composite Membranes

Authors: 
Ali, Z. - Presenter, King Abdullah University of Science and Technology
Pacheco, F., King Abdullah University of Science and Technology
Litwiller, E., KAUST
Wang, Y., King Abdullah University of Science and Technology
Han, Y., King Abdullah University of Science and Technology
Pinnau, I., King Abdullah University of Science and Technology
Aromatic polyamide thin-film composites made by interfacial polymerization are state-of-the-art membranes for reverse osmosis and nanofiltration. These membranes contain nano-defects that have essentially little effect on their performance for aqueous applications but reduce their selectivity for gas separation applications to very low Knudsen diffusion-based values. In this work, inexpensive high-performance gas separation membranes were fabricated by modifying the commercially successful reverse osmosis interfacial polymerization membrane production method. The effects of fabrication variables on the morphologies of the thin-film composite membranes optimized for gas separation applications will be presented. Defect-free thin-film composite membranes demonstrated unprecedented mixed-gas H2/CO2 selectivity of ≈ 50 at 140 °C with H2 permeance of 350 GPU (10-6 cm3(STP cm-2 s-1 cmHg-1), surpassing the hydrogen/carbon dioxide permeance/selectivity upper bound of all known polymer membranes by a wide margin. The combination of exceptional separation performance and low manufacturing cost makes them excellent candidates for cost-effective hydrogen purification from steam cracking and similar processes. Permeance and selectivity measurements imply an ultrathin polyamide layer with apparent thickness of ≈ 10-20 nm. Potential use of the membranes in challenging reverse osmosis applications will be proposed.