Evaluation of Gas‐Phase Filter Performance for a Gas Mixture

Abstract

Adsorption‐based granular activated carbon (GAC) filter is one of the common techniques for removing gas phase contaminants. However, a large group of gas phase contaminants is present in indoor environment and limited studies have been carried out to investigate the impact of contaminants type, their mixture and indoor air humidity on the GAC performance. This paper reports the outcomes of a series of experimental work which was carried out on a full‐scale system to study the impact of gas phase contaminant type (toluene, n‐hexane, and methyl ethyl ketone (MEK)), their mixture, and indoor air relative humidity (RH) level on the performance of GAC filter. It was observed that the GAC filter performed well in removing toluene in both scenarios (single and mixture) due to its high molecular weight, boiling point, and polarizability to ion formation with the GAC, followed by n‐hexane and MEK. It was also noted that the GAC filter did not perform well in removing MEK due to its weak attractive forces with GAC as compare to n‐hexane and toluene. Among the different physical properties of indoor contaminant, removal performance and service life of the tested GAC filter were positively correlated to the contaminant molecular weight. In addition, the lower dipole moment and interaction energy made the adverse effects of indoor air RH on n‐hexane more visible than toluene and MEK. Finally, a significant difference was observed between quantification indexes of the filter in removing indoor air contaminants as a single gas and as a mixture gas. The removal efficiency of GAC filter for the mixture was significantly reduced compared to those for the single gases due to the presence of other compounds in gas mixture competing for the same free space on carbon media.