Spinel Ferrite Mediated Photo-Fenton Degradation of Phenolic Analogues: A Detailed Study Employing Two Distinct Inorganic Oxidants (original) (raw)

2017, CLEAN - Soil, Air, Water

The present work demonstrates the applicability of ferrites as photo-Fenton catalysts for deterioration of different phenolic derivatives. To analyze optimal reaction conditions, experiments were performed with four magnetic spinel ferrites MFe2O4 (M = Co, Cu, Ni and Zn) and two inorganic oxidants i.e. hydrogen peroxide (HP) and potassium peroxymonosulfate (PMS). The reactions were performed using p-nitrophenol as phenolic probe. CuFe2O4 and CoFe2O4 possessed excellent ability to activate HP and PMS, respectively, among all four synthesized catalysts. Noteworthy aspect of two oxidizing agents is that the concentration of PMS used during the reaction was four times less than HP. Further the broad pH activity of PMS provides a significant advantage over HP. The optimal reaction conditions, when HP was the oxidant in the photo-Fenton degradation, are: 0.50 g/L MFe2O4, pH 2.5 and 8.8 mM HP. Although PMS was active in a wide pH range (2-10), adequate reaction conditions were: 0.50 g/L MFe2O4, natural pH and 2.2 mM PMS. The photo-Fenton activity of ferrites was extended to the degradation of different nitro-and chloro-analogs of phenol (2-nitrophenol, 3-nitrophenol, 4nitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol, 2-chlorophenol, 3-chlorophenol, 4-chlorophenol, 2,4dichlorophenol) with only two ferrites (CuFe2O4 and CoFe2O4). A comparative study was performed with the two oxidants (HP and PMS) with positive results. Finally, stability and reusability of magnetic ferrites as catalysts were also studied to prove their use in phenolic solution treatment.