Insights into enhanced removal of fluoranthene by sulfidated nanoscale zero-valent iron: In aqueous solution and soil slurry

Abstract

In this study, 90.9% fluoranthene (FLT) was degraded in sodium percarbonate (2Na2CO3·3H2O2, SPC) oxidation system by Fe(II) combined with sulfidated nano zero valent iron (S-nZVI) activation within 60 min in aqueous solution. Scavenging experiments and electron paramagnetic resonance detection suggested that HO•, O2−•, and 1O2 contributed to the removal of FLT in SPC/Fe(II)/S-nZVI system. Based on the FLT degradation intermediates that were analyzed by GC-MS in SPC/Fe(II)/S-nZVI process, three potential FLT degradation pathways were speculated. The removal efficiency of FLT was inhibited with the presence of humic acid (HA) unless the concentration of HA was controlled at 1.0 mg L−1, and the presence of 1.0 mg L−1 HA favored the generation of HO•. The excellent removal performance of FLT (88.6%) could be achieved in actual groundwater by increasing the chemical dosages and adjusting the initial solution pH to acid environment. In soil slurry tests, the optimal reaction time and soil/water ratio were obtained as 24 h and 2/10, respectively, and the desired FLT degradation performances were obtained at pH 3 and 5 with the soil/water ratio of 2/10. This work effectively demonstrates the application potential of SPC/Fe(II)/S-nZVI system for the remediation of PAHs contamination in actual industrial sites.