Evaluation of Microbial Contamination on a Carbon Dioxide Scrubber Membrane in a Recirculating-Breathing System.
Technical rept. Jul 69-May 70,
AIR FORCE FLIGHT DYNAMICS LAB WRIGHT-PATTERSON AFB OH
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This work was undertaken to support the environmental exposure and operational evaluation of a carbon dioxide scrubber based upon selective transfer of CO2 through an alkaline membrane. A filter membrane, the Solvinert type, impregnated with cesium bicarbonate, was proposed as an effective means for carbon dioxide separation in a closed-loop aviators recirculating breathing oxygen system. There was a stringent requirement for membrane integrity and membrane resistance to chemical action of the alkali and the environmental exposure conditions. The study of membrane properties when exposed to a microbially contaminated environment provided information on microorganisms capable of growth on the untreated and cesium bicarbonate impregnated membranes. Microorganisms cause a chemical degradation of materials on which they grow and induce a loss of material integrity. Also microorganisms cover a surface with growth structures which would interfere with the gas-alkaline solution interface in a scrubber membrane. The results of the work indicated that Solvinert membrane and polyethylene glycol supported growth of contaminating microorganisms but that 6.4 N cesium bicarbonate changed the medium pH such that the microorganisms did not grow. Cesium concentration at less than 0.1 N was not toxic to the contaminants Aspergillus terreus and Penicillium citrinum. Author
- Life Support Systems