To investigate the migration behaviors of hydrocarbons through a compacted organobentonite and to evaluate the effectiveness of this material as a liner for gasoline storage tanks, a demonstration-scale permeability test with detailed core sampling and mass balance of gasoline were developed for laboratory investigation. Results from this demonstration-scale test show that organobentonite not only effectively prevents the advective migration of hydrocarbons but also retards the transport of hydrocarbons. Due to the effect of surface tension between gasoline and water, the movement of gasoline through organobentonite is impeded by the repellence of molding water. It is also found that benzene has the highest mobility and is the least attenuated among the four hydrocarbons of interest (benzene, toluene, ethylbenzene, and xylene isomers; i.e., BTEX). The effluent concentrations of BTEX in the water phase are generally not very high. Moreover, substantial amounts of hydrocarbons, up to 150 of the dry weight of the org anobentonite, can be retained in the compacted liner. This indicates that compacted organobentonite can also act as an adsorbent to attenuate organic contaminants.
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