VOC removal at low contaminant concentrations using granular activated carbon

Small-scale beds of granular activated carbon (GAC) have been tested in this research using challenges of volatile organic compounds (VOCs) in air at concentrations ranging from approximately 0.5 to 100 ppm. The research linked the performance of GAC from high-concentration quickly completed tests to performance at low concentrations near those encountered indoors. For all tests, the carbon bed was approximately 2.54 cm thick and operated with a residence time of 0.11 s. The tests were conducted at 25 degrees C and 50% relative humidity. The measured 10% breakthrough times ranged from about 0.5 hour to several hundred hours. For the individual compounds, the relationship between the logarithms of breakthrough time and concentration was approximately linear over the experimental range, with different compounds producing lines having different slopes. The measured breakthrough times compared favorably to published data and models. The results suggest that higher-concentration single-component breakthrough tests, which are short and easily obtained, may be cautiously extrapolated to indoor concentrations for these compounds.