Modeling of anthracene removal from soil columns by surfactant

Abstract

In‐situ soil washing using surfactants shows great potential to remove hydrophobic organics from subsurface environments. Lab scale soil washing experiments were performed using sodium dodecylsulfate (SDS), an anionic surfactant, to remove anthracene, a highly hydrophobic compound. The formation medium chosen was fine sand. Anthracene solubility tests were conducted in batch reactors. The results showed that the solubility of anthracene increases linearly with an increase in SDS concentration above the critical micellar concentration. The kinetics of anthracene solubilization from contaminated sand in batch reactors was observed to follow the exponential Elovich equation. Column experiments were performed using either SDS solution or water to mobilize anthracene from contaminated soil. These experiments verified that SDS can be effective in removing anthracene from contaminated sand mainly due to the solubility increase by micellization. A mathematical model for soil washing was formulated using two sets of mass conservation equations for surfactant and anthracene distribution. The mixing‐cell concept was used to obtain solutions for column experiments.