Naphthalene degradation in aqueous solution by Fe(II) activated persulfate coupled with citric acid

Abstract More and more attention has been paid to polycyclic aromatic hydrocarbons (PAHs) contaminated sites caused by coking industries and chemical manufactures. In this study, the degradation performance of naphthalene (NAP), one of the typical pollutants in PAHs contaminated sites, in persulfate (PS) oxidation system activated by Fe(II) coupled with citric acid (CA) was investigated. The effects of PS, CA, and Fe(II) dosages on NAP were evaluated. 97.5% removal of NAP was obtained at the molar ratio of 15/5/1/1 of PS/Fe(II)/CA/NAP within 120 min, demonstrating that the addition of CA could significantly strengthen NAP degradation. The results of probe tests, EPR detection and scavenging experiments suggested that HO• played a predominant role in the degradation of NAP. The effect of surfactants including tween-80 (TW-80) and sodium dodecyl sulfate (SDS) on NAP degradation was explored. Moreover, the major degradation intermediates of NAP were determined by GC-MS and the possible degradation pathways of NAP were proposed. Finally, the effectiveness of PS/Fe(II)/CA process for NAP degradation in the actual groundwater demonstrated that this technique has a remarkable preponderance and prospect in NAP contaminated groundwater remediation.