Investigation of the Ozonation of Highly PAXHs Contaminated Soil Using Ultrahigh Resolution Mass Spectrometry

Abstract

Ozonation is an effective chemical treatment technique for removing contamination from the environment. In some countries it is used to clean up drinking water instead of using chlorinated treatment. The contamination of soil with polyaromatic compounds (PAXHs with X = N, S or O) are some almost forgotten contaminants but describe very toxic and by now almost omnipresent chemical contaminations. The extremely high number of different PAXHs are strongly adsorbed on soil and a method is introduced where an organic solvent is used to facilitate the reaction of the contaminant with ozone. In this study ozone is applied for 6 or 18 h with addition of toluene and the different phases (organic, water, and extract of soil phase) are studied to understand the ozonolysis of polycyclic aromatic hydrocarbons and their derivatives. The reaction is studied using ultrahigh resolution mass spectrometry (UHRMS) allowing a comprehensive characterization of the initial contaminants as well as the various oxidation products. The results show that the ozonation treatment leads to continuous degradation of already oxidized compounds and a wide range of oxidation products can be detected.