Insights into the removal of fluoranthene by sodium percarbonate activation with pyrite: Performance, mechanism, and degradation pathways

Sodium percarbonate (SPC) induced advanced oxidation processes have been used for the remediation of polycyclic aromatic hydrocarbons (PAHs) contamination, however, the feasibility studies of SPC and pyrite (FeS2) process are scarce. In this work, FeS2 served as a catalyst and reductant to activate SPC for fluoranthene (FLT) removal. 100% FLT removal was obtained at an initial solution pH of 5.90 with FeS2 and SPC dosages of 0.5 g/L and 0.02 mM, respectively, and the influences of initial aqueous solution pH, dissolved oxygen, and various aqueous solution matrixes on FLT degradation were explored. Based on the results of electron paramagnetic resonance detection and scavenging experiments, it was demonstrated that HO•, 1O2, and O2−• played dominant roles in the removal of FLT, whereas CO3−• could only be involved in the ROS proliferative reaction in FeS2/SPC process due to the weak oxidizing capacity. Additionally, three FLT degradation pathways were proposed based on the detected degradation intermediates 1-phenylnaphthalene, indane, and phthalic acid. Finally, the desorption of FLT in soil was investigated by employing surfactants and organic acids, with organic acids being less effective than surfactants. Since the majority of organic acids can be utilized as advanced oxidation process promoters, their practical application is advantageous.