Utilization of almandite for activation of peroxymonosulfate, hydrogen peroxide, and sodium sulfite to effectively...

This study explores the catalytic potential of almandite, a natural garnet mineral, for activating three typical oxidants, including peroxymonosulfate (PMS), H₂O₂, and Na₂SO₃, to degrade ibuprofen (IBP). We established three stable oxidation systems and evaluated their performance, verifying the universality of Almandite's application in AOPs. Notably, S(IV) in Na₂SO₃ facilitated Fe (III)-to-Fe (II) reduction in homogeneous and heterogeneous phases, enhancing catalytic stability and recyclability. Advanced spectroscopic analyses (EPR, radical quenching, and probe techniques) identified key reactive oxygen species (ROS) as SO₄^•-, •OH, ¹O₂, and O₂^•- in PMS system, •OH and O₂^•- in H₂O₂ system, and SO₃^•- as dominant species in Na₂SO₃ system. Degradation pathways identified by HPLC-QTOF-MS showed effective breakdown of IBP into low-toxicity products. Among the systems, H₂O₂/Almandite exhibited the strongest oxidation and pollutant removal capacity, while Na₂SO₃/Almandite provided superior resistance to environmental interference and recyclability. These findings highlight the versatility and environmental value of almandite as a low-cost, effective, and selective catalyst in advanced oxidation processes, offering tailored solutions for water purification under varying conditions.