Oxidative photodegradation of pyrene and fluoranthene by Fe-based and Zn-based Fenton reagents

Abstract

Increased industrialization has introduced a lot of hazardous materials into ecosystems. Polycyclic aromatic hydrocarbons (PAHs) are among the most toxic and persistent organic pollutants emanating from petrochemical industrial areas. Remediation of PAHs-contaminated soil has been a particularly big challenge. Photochemical oxidation-reduction processes have gained attention because of their high efficiency and robustness for PAH removal from contaminated soils. In this study, the efficacy of Fe-based and Zn-based Fenton reagents for remediating soil contaminated with pyrene (Pyr) and fluoranthene (Flr) is evaluated. UV treatment (2-h exposure) at 254 nm resulted in 21.6 and 28.5% degradations of Pyr and Flr, respectively. The Zn-based Fenton reagent performed better than the Fe-based reagent by degrading 99.9% of Pyr. The Fe-based Fenton reagent (under UV light) resulted in 97.1-99.7% and 95.1-98.9% Pyr and Flr degradations, respectively, in 0.5-2 h. Notably, the temperature increase during UV irradiation facilitated the enhanced degradation of Pyr and Flr, as observed from negative correlations (r = (-)0.902-0.961 and p = 0.039-0.098) between the temperature and PAH concentrations. The newly tested Zn-based Fenton reagent was equally effective as the Fe-based Fenton reagent in degrading Pyr and Flr in soil. Hence, it can be used as a new alternative reagent to remediate PAH-polluted soils.