Credit: Image courtesy of Sandia National Laboratories
Enzymatic liquid membrane design and mechanism of carbon dioxide capture and separation. The Sandia/University of New Mexico membrane is fabricated by formation of 8-nanometer diameter mesopores. Using atomic layer deposition and oxygen plasma processing, the silica mesopores are engineered to be hydrophobic except for an 18-nm-deep region at the pore surface which is hydrophilic. Through capillary condensation, carbonic anhydrase enzymes and water spontaneously fill the hydrophilic mesopores to form an array of stabilized enzymes with an effective concentration greater than 10 times of that achievable in solution. These catalyze the capture and dissolution of carbon dioxide at the upstream surface and the regeneration of carbon dioxide at the downstream surface. The high enzyme concentration and short diffusion path maximizes capture efficiency and flux.