Remediation of Chlorobenzene Polluted Aquifer by Surfactant-Enhanced Air Sparging

The strengthening effect of anionic surfactant sodium dodecyl benzene sulfonate (SDBS) on air sparging (AS) was investigated using a series of one-dimensional column experiments. The results show that the addition of SDBS into groundwater lowered the groundwater surface tension, which in turn reduced the air entry capillary pressure. As a result, the air saturation in groundwater was increased accordingly. At the air injection rate of 100 mL/min, the surface tension reduction from 72.2 mN/m to 49.5 mN/m led to air saturation enhancement from 13.2% to 50.1%. As the surface tension further decreased, the air saturation no longer increased, but slightly reduced instead. Through the contaminant removal experiment, it was found that the addition of SDBS greatly increased the chlorobenzene removal efficiency, and the change trend of removal efficiency was almost the same to the change of air saturation. Thus, the addition of surfactant into groundwater can be an effective method to enhance air sparging.