Abstract: A carbon dioxide (CO2) adsorption membrane or bed is operative to separate metabolic CO2 from an exhaust stream from a breathable atmosphere which is discharged from a closed habitable environment. The habitable environment is in a low ambient pressure surrounding. A portion of the scrubbed exhaust gas stream is diverted from the habitable environment and passed through a desorption chamber. The desorption chamber is open to the low ambient pressure surrounding to maintain a pressure which is slightly greater than the pressure in the ambient surrounding so that the desorption chamber gas stream will exit the system into the ambient surroundings. When the diverted exhaust gas enters the low pressure desorption pressure chamber its CO2 partial pressure content is reduced. The reduced CO2 partial pressure content of the gas stream in the desorption chamber enables the desorption chamber gas stream to remove CO2 from the adsorption membrane or bed.

Abstract: Water vapor is removed from a mixture of air, metabolic carbon dioxide (CO2), and water vapor prior to removing the CO2 from the mixture. The water vapor-containing mixture is passed through a membrane module which is operative to separate the water vapor from the air and CO2 mixture. The water vapor in the entering mixture will pass in one direction through the membrane in the module from an entry side of the membrane to an exit side of the membrane. The membrane divides the module into two chambers, one of which receives the water vapor-containing mixture, and the other of which receives CO2-free air from a CO2 adsorbant station. The water vapor-containing mixture is removed from a closed habitable environment such as a space station, a space suit, a submarine, or the like, and is moved through the membrane module where the water vapor is removed from the gas stream.