Abstract
Formaldehyde solution is widely accepted as a liquid sterilizing agent for animal research and pharmaceutical facilities. After the fumigation by formaldehyde gas, the indoor air is contaminated by the residual gas at hundreds to thousands part-per-million, and hence the concentration levels should be reduced before evacuation into atmosphere to meet emission criteria. This study aimed to develop a novel air cleaning device for the removal of formaldehyde gas residue employing manganese dioxide as a major ingredient of the honey-comb air filter. A prototype device was tested in a full-scale and closed chamber (23 m3) with demonstrations of formalin fumigation. The results showed the device significantly decreased 500-3000 ppm of formaldehyde with a production of equimolar carbon dioxide in the chamber even at room temperature. Though the time courses of formaldehyde concentration depended on the initial concentration, levels of the residual gas decreased below the emission criteria within eight hours. These results suggested the possible use of this methodology for post-treatment of formalin fumigation.
