Abstract: A method is provided for making low-cost CO2 sorbents that can be used in large-scale gas-solid processes. The improved method entails treating an amine to increase the number of secondary amine groups and impregnating the amine in a porous solid support. The method increases the CO2 capture capacity and decreases the cost of utilizing an amine-enriched solid sorbent in CO2 capture systems.

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.