Testbed for Determining the Filtering Capacities of COTS Adsorbents

A lab-scale testbed for screening and characterizing the chemical specificity of commercial “off-the-shelf” (COTS) polymer adsorbents was built and tested. COTS polymer adsorbents are suitable candidates for future trace contaminant (TC) control technologies. Regenerable adsorbents could reduce overall TC control system mass and volume by minimizing the amounts of consumables to be resupplied and stored. However, the chemical specificity of these COTS adsorbents for non-methane volatile organic compounds (NMVOCs) (e.g., methanol, ethanol, dichloromethane, acetone, etc) commonly found in spacecraft is unknown. Furthermore, the effect of humidity on their filtering capacity is not well characterized. The testbed, composed of a humidifier, an incubator, and a gas generator, delivers NMVOC gas streams to conditioned sorbent tubes. The testbed was used to measure the amount of water vapor adsorbed by four candidate COTS adsorbents and to determine the adsorptive capacities of Carbopack B and Carbosieve SIII using simulated gas streams (e.g., relative humidity, temperatures, and NMVOC loads) found in manned spacecraft.