Efficiency of foam flushing remediation in heterogeneous soil contaminated by nitrobenzene

Abstract The spatial distribution of nitrobenzene in a heterogeneous medium during the foam flushing remediation process was investigated through a two-dimensional simulation device. The remediation efficiency and the mechanisms of action of the surfactant foam remediation process in heterogeneous media were also studied. The experiments showed that during the contamination process, nitrobenzene preferentially enters the low-permeability zones of the medium and is intercepted as a free phase, bypassing the high-permeability zones. In the surfactant foam remediation process, a total removal rate of 95.7% was achieved, with the mobilization effect contributing 69.5%, and the solubilization and volatilization contributing 21.6% and 1.5%, respectively. Mobilization, solubilization, and volatilization are the main mechanisms by which nitrobenzene is eliminated from the soil during the surfactant foam remediation process. Finally, it has also been observed that this process showed a higher removal efficiency in high-permeability media than in low-permeability media due to interface effects.