Comparison Study on FeS-Activated Peroxymonosulfate, Persulfate, and Hydrogen Peroxide for Allura Red AC Decoloration

Peroxymonosulfate (PMS), persulfate (PS), and hydrogen peroxide (H2O2)-based advanced oxidation processes (AOPs) activated using iron-based materials are widely used for recalcitrant wastewater oxidation. In this study, iron sulfide (FeS), a ubiquitously distributed iron-containing mineral, is used as an activator of PMS, PS, and H2O2 for Allura Red AC (AR AC) decoloration. The results demonstrated that FeS/PMS, FeS/PS, and FeS/H2O2 can effectively decolorize 0.05 mM AR AC, and the decoloration efficiencies were 95.24%, 84.15%, and 88.18%, respectively, within 30 min with dosages of 5 mM oxidants and FeS. Moreover, FeS/PMS, FeS/PS, and FeS/H2O2 enable the disposal of AR AC effluents containing different concentrations of inorganic salts (other than CO32−), and humic acid. Moreover, FeS demonstrates excellent flexibility and recyclability on PMS, PS, and H2O2 activation for AR AC decoloration. The hydroxyl radical (•OH) is the primary reactive oxygen species responsible for the decoloration and mineralization of AR AC by FeS/PMS, FeS/PS, and FeS/H2O2. Therefore, FeS is a versatile activator, and FeS/PMS, FeS/PS, and FeS/H2O2 are highly recommended as the alternative AOPs in the future for AR AC effluent purification.