Soil vapor extraction (SVE) is one of the effective techniques of removing volatile chlorinated hydrocarbon contaminants from soil. However, the extracted soil gas needs further treatment. In this work, adsorptive treatment of soil gas using regenerable activated carbon fiber (ACF) was investigated. The equilibrium relation of tetrachroloethylen (PCE) adsorbed on ACF was accurately expressed by the Dubinin-Radushkevitch equation, which enabled prediction of the amount of PCE adsorbed at given temperature and concentration. Then, adsorption and desorption of PCE and other volatile organic compounds (VOCs) in contaminated soil at a commercial cleaning factory were investigated using a newly developed steam-regeneration ACF adsorption apparatus installed at the field site. Due to high temperatures of the soil gas extracted and the resulting decrease in relative humidity thereof, reduction in the amount of PCE adsorbed on ACF by coadsorption of water vapor was negligibly small. The amount of PCE adsorbed on ACF to a breakthrough did not reach the amount predicted for a single gas phase of PCE. When the exhausted ACF was regenerated with steam, PCE was desorbed almost completely. In this regeneration, more than 30 species of hydrocarbons derived from petroleum-based detergents, which were not detected during a soil contamination survey at the site, were also desorbed. It is assumed that the coadsorption of these hydrocarbons led to the reduced amount of PCE adsorbed on ACF.
