Degradation of ethylbenzene in aqueous solution by sodium percarbonate activated with EDDS–Fe(III) complex

Ethylbenzene (EB) degradation performance in (S,S)-ethylenediamine-N,N-disuccinic acid (EDDS) chelated Fe(III) activated sodium percarbonate (SPC) system was investigated in this study. The effects of various factors, such as the dosages of SPC and Fe(III), molar ratio of EDDS/Fe(III), anions (Cl⁻, HCO₃⁻, SO₄²⁻, and NO₃⁻) concentration, natural organic matters (NOM), and initial solution pH were evaluated. The results showed that the addition of EDDS remarkably improved the EB removal in Fe(III)/SPC system. Both HCO₃⁻ anions and NOM had significantly inhibitive effect, while the influence of SO₄²⁻, Cl⁻ and NO₃⁻ could be negligible on EB degradation. The EB removal was inhibited at extremely low and high initial solution pH. Moreover, the results of free radical probe tests, scavenger tests and electron paramagnetic resonance (EPR) detection indicated that ^[rad]OH was the predominant species responsible for EB degradation even though both ^[rad]OH and O₂^−[rad] were generated in the SPC/EDDS–Fe(III) system. The oxidation products were analyzed and possible EB degradation pathways were proposed. In conclusion, this study provides an important insight into the application of SPC/EDDS–Fe(III) system in the removal of EB contaminant, especially for in situ remediation of BTEX-contaminated groundwater.