Highly permeable membrane materials for CO2 capture†
Abstract
The release of large quantities of CO2 into the atmosphere has been linked to global warming and climate anomalies. Membrane processes offer a potentially viable energy-saving alternative for CO2 capture in comparison with conventional technologies such as amine absorption. However, gas separation membranes that are currently available have insufficiently high permeance (flux) for large scale applications such as the treatment of high volume flue gas with low concentration of CO2. Here we demonstrate a class of thin film composite (TFC) membranes, consisting of a high molecular weight amorphous poly(ethylene oxide)/poly(ether-block-amide) (HMA-PEO/Pebax® 2533) selective layer and a highly permeable polydimethylsiloxane (PDMS) intermediate layer which was pre-coated onto a polyacrylonitrile (PAN) microporous substrate. In contrast to the performance of conventional materials, the selective layer of TFC membranes shows super-permeable characteristics and outstanding CO2 separation performance. This unprecedented result arises from the introduction of HMA-PEOs into the Pebax® 2533 matrix, leading to high CO2 permeability and flux. These results provide an encouraging direction to further develop TFC membranes for efficient CO2 capture processes.