(646c) CO2 Facilitated Transport Membranes

Membrane separation is a promising technology for CO₂ separation and capture because of the high energy efficiency, small footprint and operational simplicity. CO₂ facilitated transport membrane is an important group of membranes for CO₂ separation. This work first reviews the state of the art in CO₂facilitated transport membranes, followed by some current results on novel amine-containing membranes.

In this work, the facilitated transport mechanism is described in conjunction with the chemical reactions of CO₂and amine carriers. A wide range of facilitated transport membranes is discussed, including amine-based fixed-site carrier membranes, amine mobile carrier-containing membranes, and other facilitated transport membranes with different types of carriers and/or inorganic fillers to further improve the performance of facilitated transport membranes.

High molecular weight polyvinylamine was successfully synthesized in our group, which served as the fixed site carrier and the polymer matrix to incorporate mobile carriers into the membranes. The membranes demonstrated a CO₂ permeance of 757 GPU and a CO₂/N₂ selectivity of 151 under the typical conditions for flue gas CO₂ capture (57 °C, 1 atm, 100% relative humidity, 20% CO₂ in the feed gas balanced with N₂ on a dry basis). As reported that the CO₂ loading capacity of sterically hindered amine can be twice of unhindered amine in aqueous solution, the high molecular weight polyvinylamine was also modified into sterically hindered polyvinylamine in this work and demonstrated up to 24% improvement in CO₂ permeability and 14% increase in CO₂/N₂ selectivity. Sterically hindered polyvinylamine has the potential to become the next-generation fixed site carriers for CO₂ facilitated transport membranes.