Investigating the Degradation Mechanism of Phenanthrene by Fe 2+ -Activated Persulfate

Abstract

The degradation of phenanthrene (PHE) by Fe²⁺-activated persulfate (PS) has been investigated. The effects of different concentrations of Fe²⁺ and PS on the degradation of PHE have been explored, and the degradation mechanisms have been studied. The results indicate that when the initial concentration of PHE was 0.3 mM, the best PHE degradation conditions were found using PS and Fe²⁺ concentrations of 10 and 5 mM, respectively. The degradation rate, mineralization rate, PS consumption rate, and oxidant efficiency were 89%, 54%, 97%, and 5.49, respectively. The degradation of PHE followed a pseudo-first-order kinetic model, and the reaction rate constant (k) was in the range of 0.0029–0.0768 h⁻¹. Free radical quenching studies have revealed that SO₄⁻· was the predominant radical species for PHE oxidation under acidic condition. The PHE degradation pathways in the Fe²⁺/PS system have been proposed based on the identification of the PHE intermediates observed in our study.