Remediation of phenanthrene from contaminated kaolinite by electroremediation-Fenton technology

Abstract

Polycyclic aromatic hydrocarbons (PAHs) cause a high environmental impact when released into the environment. The objective of this study was to evaluate the capacity to decontaminate polluted soils with phenanthrene as a model PAH using a combination of two technologies: electrokinetic remediation and Fenton process. Kaolinite was used as a model sample that was artificially polluted at the laboratory at an initial concentration of phenanthrene of 500 mg kg⁻¹ of dried kaolinite. The standard electrokinetic process resulted in negligible removal of phenanthrene from the kaolinite sample. Faster and more efficient degradation of this compound can be promoted by introduction of a strong oxidant into the soil such as hydroxyl radicals. For this reason, the Fenton reactions have been induced in several experiments in which H₂O₂ (10%) was used as flushing solution, and kaolinite polluted with iron was used. When anode and cathode chambers were filled with H₂O₂ (10%), the kaolinite pH is maintained at an acid value around 3.5 without pH control and an overall removal and destruction efficiency of phenanthrene of 99% was obtained in 14 days by applying a voltage gradient of 3 V cm⁻¹. Therefore, it is evident that a combined technology of electrokinetic remediation and Fenton reaction is capable of simultaneously removing and degrading of PAHs in polluted model samples with kaolinite.

Keywords:

• Electroremediation
• Fenton reaction
• hydrogen peroxide
• PAHs
• phenanthrene

Acknowledgments

This research was financed by the Spanish Ministry of Science and Technology and European FEDER (Project CTM2004-01539/TECNO).