Study of the adsorption/removal efficiency of woven and nonwoven activated carbon fabrics for MEK

The initial gaseous contaminant removal efficiency and adsorption characteristics for various commercially available activated carbon fabrics were determined at air flow rates, air temperature and pressure drop typical of an indoor air residential or small office environment. Methyl ethyl ketone (MEK) was used as the hazardous air pollutant for the laboratory tests. For the range of MEK concentrations tested, the initial fabric adsorption efficiency decreased as concentration increased, although the total adsorption capacity (g/g) increased. Initial fabric efficiencies were also higher at a lower air flow rate. The pure activated carbon nonwoven felt had higher adsorption capacity as well as higher initial adsorption efficiencies than the woven carbon fabrics tested. In all of the fabrics which were tested, the maximum adsorption efficiency was achieved initially, lasted only momentarily, then steadily decreased until adsorption capacity was reached. It was also observed that fabrics that had reached capacity, but were then subjected to the same air flow conditions as occurred during the adsorption process (except without the MEK present), immediately began to desorb the adsorbed MEK. This raises concern about the application of carbon adsorption systems for indoor environments, if concentrations are highly variable due to the potential of desorption from the fabric.