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Evaluating a Reusable Filter for Controlling Volatile Organic Compounds in Plant Growth Chambers. J. Williams1, J. Elmer2, and O. Monje3  1University of West Georgia, 2University of Missouri - Rolla, and 3Dynamac Corporation

   Volatile organic compounds (VOCs) found in spacecraft are detrimental to the health of plants grown in spacecraft if allowed to accumulate to toxic levels.  To prevent this, VOCs must be continuously removed from the spacecraft air using passive filters, photo catalytic scrubbers or adsorbent filters.  A reusable filter using Carbosieve SIII, a thermally desorbing filter media, was built to control VOC levels in a 21 day long plant growth experiment.  The effectiveness of the VOC filter in controlling VOCs was tested and compared against a passive commercial ethylene filter and an unfiltered control.

   To measure the amount of VOCs in the air, two 0.5mL samples were collected in syringes and analyzed using a gas chromatograph.  Daily air samples were taken for the entire 21 day growth period and compared to a standard gas which contained a known   concentration of VOCs. The chambers began with a leak rate of 63% per hour but in an attempt to lower relative humidity (RH) we increased the leak rate to 400% per hour on 12 days after planting (DAP) and had no effect on the RH.

   To test the reusability of the filter we loaded it with VOCs and the desorbed the filter.  After desorbing the filter we were able to reload the filter to the same capacity as the previous loading. 

   The prototype VOC filter was shown to be reusable and effective at controlling VOCs with the chamber leak rate was near 63% the total volume per hour. However, the VOC filter did not remove acetone and methanol after 12 DAP.

(Supported by the 2005 Spaceflight and Life Sciences Traineeship Program)