Ultra-thin enzymatic liquid membrane for CO 2 separation and capture
Here, the limited flux and selectivities of current carbon dioxide membranes and the high costs associated with conventional absorption-based CO 2 sequestration call for alternative CO 2 separation approaches. Here we describe an enzymatically active, ultra-thin, biomimetic membrane enabling CO 2 capture and separation under ambient pressure and temperature conditions. The membrane comprises a ~18-nm-thick close-packed array of 8 nm diameter hydrophilic pores that stabilize water by capillary condensation and precisely accommodate the metalloenzyme carbonic anhydrase (CA). CA catalyzes the rapid interconversion of CO 2 and water into carbonic acid. By minimizing diffusional constraints, stabilizing and concentrating CA within the nanopore array to a concentration 10× greater than achievable in solution, our enzymatic liquid membrane separates CO 2 at room temperature and atmospheric pressure at a rate of 2600 GPU with CO 2 /N 2 and CO 2 /H 2 selectivities as high as 788 and 1500, respectively, the highest combined flux and selectivity yet reported for ambient condition operation.