Optimization of the application of the Fenton chemistry for the remediation of a contaminated soil with polycyclic aromatic hydrocarbons

Abstract

BACKGROUND: A contaminated soil with 100mgkg-1 each of the following pollutants: anthracene (ANT), phenanthrene (PHE), pyrene (PYR) and benzo(a)pyrene (BaP) was treated by three different kinds of Fenton's reaction without pH adjustment, Fenton-like reaction (hydrogen peroxide (H2O2) with a ferric iron salt (Fe(III)), Fenton catalyzed with nanoparticles of zerovalent iron (nZVI), and Fenton-like reaction coupled simultaneously with soil washing, using sodium dodecyl sulfate (SDS) as surfactant. The influence of initial iron concentration (1-5mmolL-1), oxidant dosage (88-1765mmolL-1), type of iron initially added (Fe(III) or nZVI) and effect of surfactant addition were tested. RESULTS: Almost total conversion of ANT and BaP was achieved for the majority of the experiments, having obtained the best results for the Fenton like reaction with initial Fe(III) concentration of 5mmolL-1, where a total abatement for all contaminants was obtained in less than 10 days. Besides, the coupling of Fenton reagent and soil washing enhanced the removal of the PAHs studied. 9-10 anthraquinone (ATQ) was detected as the main aromatic intermediate. CONCLUSIONS: The results put forward in this work reveal the suitability of new effective alternatives to conventional Fenton Reagent for the removal of PAH in soils.