Enhanced Electrokinetic Remediation of Pyrene-Contaminated Soil Through pH Control and Rhamnolipid Addition

Electrokinetic (EK) remediation is considered an effective technology for removal of persistent, toxic, and hydrophobic polycyclic aromatic hydrocarbons, such as pyrene, from soils. We propose a method involving use of pH control and rhamnolipid addition for enhancing pyrene removal efficiency of EK remediation. Pyrene removal efficiency was successfully improved by cycling the electrolyte, exchanging electrodes, and implementing an electrolyte pH of 7, with high values of 12.12%, 10.48%, and 14.00% being achieved, respectively, compared to the 0.35% achieved with traditional EK treatment. Effect of rhamnolipid addition on the EK removal of pyrene was also investigated. When rhamnolipid was added to the electrolyte, solubility of pyrene increased, thus resulting in improved removal efficiency. With an increase in rhamnolipid concentration from 0.5 to 2 g/L, pyrene removal efficiency increased from 14.74% to 24.81%, reaching 93.60% in the section closest to the anode. These results indicate that use of pH control and rhamnolipid addition is effective in enhancing the EK remediation of pyrene-contaminated soil.