Abstract
The Electrokinetic-Fenton (EK-Fenton) process is a powerful technology to remediate organic-contaminated soil. The behavior of salts and acids introduced for the pH control has significant influence on the H2O2 stabilization and destruction of organic contaminants. In this study, the effects of the type and concentration of acids, which were introduced at the anode, were investigated for the treatment of clayey soil contaminated with phenanthrene. In experiments with H2SO4 as the anode solution, H2O2 concentration in the anode reservoir decreased due to reaction between reduced species of sulfate and H2O2, as time elapsed. By contrast, HCl as an electrolyte in the anode reservoir did not decrease the H2O2 concentration in the anode reservoir. The reaction between the reduced species of sulfate and H2O2 hindered the stabilization of H2O2 in the soil and anode reservoir. In experiments with HCl for pH control, Cl·, and Cl2 · −, which could be generated with mineral catalyzed Fenton-like reaction, did not significantly hinder H2O2 stabilization. H2O2 transportation with electro-osmotic flow and mineral catalyzed Fenton-like reaction on the soil surface resulted in the simultaneous transport and degradation of phenanthrene, which are dependent of the advancement rate of the acid front and electro-osmotic flow toward the cathode according to HCl and H2SO4 concentrations in the anode purging solution.