Coating magnetic CuFe2O4 nanoparticles with OMS-2 for enhanced degradation of organic pollutants via peroxymonosulfate activation

A heterogeneous magnetic CuFe 2 O 4 @OMS-2 catalyst was fabricated through a facile solvent-free process using Mn(CH 3 COO) 2 and KMnO 4 in the presence of CuFe 2 O 4 . It was found that the BET surface area of OMS-2 as well as the ratio of low-valent manganese species significantly increased in the hybrid catalyst, due to interactions between CuFe 2 O 4 and the precursor of amorphous manganese oxide . Acid Orange 7 (AO7) and other organic pollutants could be completely degraded by the CuFe 2 O 4 @OMS-2 catalyst within 30   min in the presence of peroxymonosulfate (PMS), while CuFe 2 O 4 and OMS-2 showed no significant activity for the reaction. The hybrid catalyst also exhibited excellent long-term stability and could be easily recovered with the assistance of an external magnetic field. A possible degradation mechanism for the synergistic effects of different valent metal species and reactive radicals was proposed, which involved the electron transfer from Mn(III) or Mn(II) species to PMS with the generation of sulfate and hydroxyl radicals, and from AO7 and Cu(I) in CuFe 2 O 4 to Mn(IV) and Mn(III) to reduce these Mn species.