Enhancement effect of Fe(III) on the degradation of fluoranthene by iron sulfide-activated percarbonate: Performance and mechanism

Abstract

In the advanced oxidation process for the remediation of organic contaminated water and soil, sodium percarbonate (SPC) is regarded as a potential oxidant. Iron sulfide (FeS) was chosen as an activator in this work for assisting fluoranthene (FLT) removal, with Fe(III) addition overcoming the solution pH constraint on FLT removal in the SPC/FeS process. At the optimal chemical dosages, SPC/FeS (pH = 3.0) and SPC/FeS/Fe(III) (pH = 5.7) processes removed approximately 100% and 92.8% of FLT, respectively. Based on the results of scavenging trials and electron paramagnetic resonance analysis, HO• was the dominant reactive oxygen species in FLT removal by SPC/FeS and SPC/FeS/Fe(III) processes. Dissolved oxygen (DO) played a crucial role in FLT removal, and SPC/FeS/Fe(III) process was more dependent on DO than SPC/FeS process. Both processes overcame the limitation of Cl– on the application of SPC-induced oxidation process. In actual groundwater experiments, 95.5% of FLT was removed in SPC/FeS/Fe(III) process at an initial solution pH of 5.0. In soil slurry trials, 12 h was the optimal reaction time for FLT removal, and the SPC/FeS and SPC/FeS/Fe(III) processes degraded 85.6% and 86.7% of FLT, respectively. In conclusion, the FeS-activated SPC-induced oxidation process offers perspectives for PAHs contaminated field decontamination and contributes to the optimization of modern oxidation methods.