DEVELOPING NOVEL ADSORBENT MATERIALS FOR CARBON DIOXIDE REMOVAL FROM ENCLOSED ENVIRONMENTS

Exposure to high CO2 levels in enclosed environments may result in adverse health impacts. To provide a safe breathing environment, the exhaled gases must be removed. Currently, NASA uses a multi-bed system known as the Carbon Dioxide Removal Assembly (CDRA) for CO2 removal. The process involves cyclic adsorption-desorption using zeolite-5A molecular sieves. Owing to the presence of a wet gaseous mixture and the hydrophilic nature of zeolite-5A, the removal of CO2 and water vapor must be conducted in two separate vessels, resulting in additional costs. Therefore, the objective of this study was to integrate and intensify the process utilizing amine-grafted silica. Adsorbent performance was gauged on equilibrium CO2 uptake and kinetics, activation temperature, CO2 desorption temperature, and consecutive cycling in the presence of 1 vol.% CO2 in N2 at 25 °C. Aminosilica outperformed 5A and achieved similar equilibrium CO2 uptake while exhibiting faster kinetics, and lower desorption and regeneration temperature requirements.