LAUSR

Abstract In this work, CeO 2 -Fe 3 O 4 nano-composite (CeFe) was synthesized and applied to activate peroxymonosulfate (PMS) for degradation of synthetic dye Direct red 16 (DR16). X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), vibrating sample magnetometery (VSM), Brunauer–Emmett–Teller (BET) specific surface area and energy dispersive spectroscopy (EDS) were used to characterize CeFe. Operational parameters of pH, PMS and CeFe dosages were studied. Complete decolorization was obtained at pH = 7.0, 1.5 mM PMS and 0.3 g/L catalyst dosage and 25 min reaction time. Reusability and leaching experiments showed that CeFe nano-composite was a stable and recoverable catalyst for four cycles. Ultraviolet (UV) and ultrasound (US) irradiation improved the rate constant considerably. Fulvic acid, bicarbonate ions and sodium dodecyl sulfate exhibited the inhibitory effect on decolorization in CeFe/PMS. CeFe was effective to activate other chemical oxidants such as persulfate, hydrogen peroxide and percarbonate. Sulfate radical was found as dominant radical in CeFe/PMS while hydroxyl radicals also contributed in DR16 degradation in CeFe/PMS/UVA-LED and CeFe/PMS/US. The performance of CeFe/PMS was also studied on several organic pollutants (direct orange 26, bisphenol A, 2,4,6-trichlorophenol and benzotriazole) and real wastewater.