Fenton Processes for Remediation of Polluted Soils

Soil pollution poses threat to the environment due to persistence of pollutants, which are strongly sorbed and thus difficult to remove. The treatment processes based on the Fenton reaction, generate a powerful oxidant, the hydroxyl radical, by catalytic decomposition of hydrogen peroxide. This reaction can be carried out in polluted soils by injection of H2O2, and the iron naturally present in the soil acts as a catalyst. However, the penetration of H2O2 into the target treatment zone, especially in low permeability soils, is the main drawback of the process. In order to overcome this drawback, ElectroKinetic treatment can be coupled with the Fenton treatment. Under this combined process, the reagents can be homogeneously distributed in the soil by the electric field action independently of soil permeability. In this context, the addition of H2O2 on the electrolyte chambers and the presence of iron in the soil are requested. In this chapter, the approach based on the principles of Fenton and ElectroKinetic treatment is presented. Applying this combined process, ElectroKinetic-Fenton, the degradation of the pollutant in the soil could be produced by the hydroxyl radicals generated. Nevertheless, this process may present some limitations regarding the presence of iron, the difficulty in selection of reagent concentration, the importance of the electrode disposition, and so on. Some considerations, proposed for different investigations, are collected and analyzed in this chapter, in order to facilitate future in situ treatment of real polluted sites.