Structurally modified CuFe₂O₄/persulfate process for acetaminophen scavenging: high efficiency with low catalyst addition

Abstract

BACKGROUND: Iron (Fe)-copper (Cu) bimetallic catalysts such as CuFe 2 O 4 , CuFeO 2 and CuO/Fe 3 O 4 have been widely applied in persulfate oxidization process. Among these catalysts, CuFe 2 O 4 has shown excellent performance in catalyzing peroxymonosulfate. However, because the catalytic effect of CuFe 2 O 4 on persulfate (PS) is not obvious, the application of CuFe 2 O 4 to activate persulfate has been investigated only rarely. Hence, structural modification has been applied in order to improve the catalytic activity of CuFe 2 O 4 on persulfate.RESULT: In this study, Oxygen (O)-deficient CuFe 2 O 4 was synthesized via the hydrogen reduction method and first used to activate PS for degrading acetaminophen (APAP) in aqueous solution with low catalyst concentration of 0.3 g L −1 . Results reveal that high-concentration APAP (100 mg L −1 ) could be efficiently removed by O-deficient CuFe 2 O 4 -activated PS, and 91% removal rate could be reached in 60 min using 0.8 g L −1 PS and 0.3 g L −1 catalyst under unadjusted pH. Dissolved O 2 and Cl − showed inhibitory effects on the degradation process. Radical scavenger experiments, in which methanol, tert-butyl alcohol (TBA) and nitrobenzene (NB) were used as radical trappers, indicated that SO 4 − and OH were the active radicals in the reaction, but the main radical was SO 4 − . Oxygen-deficient CuFe 2 O 4 showed strong reduction ability and could activate PS efficiently, and the electron transfer capability was remarkably enhanced after this structural modification. CONCLUSIONS: Results indicated that compared to the pristine crystal, the catalytic activity of CuFe 2 O 4 could be improved through structural modification. Additionally, the structurally modified catalyst showed high potential to treat wastewater with high antibiotic content under mild conditions. Romero A. Oxidation of priority and emerging pollutants with persulfate activated by iron: effect of iron valence and particle size. Chem Eng J 318:197-205 (2017).J Chem Technol Biotechnol 2019; 94: 785-794

Synthesis of Spinel Ferrite MFe2O4 (M = Co, Cu, Mn, and Zn) for Persulfate Activation to Remove Aqueous Organics: Effects of M-Site Metal and Synthetic Method

“…Therefore, ferrites with different M-site metals were characterized by FTIR spectra (Figure 4). The broad bands at about 3,416 cm −1 of all samples indicated the obvious presence of hydroxyl group (-OH) (Zhang et al, 2019). The peak at 1,625 cm −1 was due to the deformation vibration of water molecules in the interlayer (Parvas et al, 2014).…”

“…Obviously, the proportion of Fe(II) in CuFe 2 O 4 -SG and CuFe 2 O 4 -CP was much higher than that in CuFe 2 O 4 -ST. These results were favorable for organics removal because Fe was also an electron donor for PS activation (Zhang et al, 2019).…”

“…The calculation of peak area showed that CuFe 2 O 4 -ST contained more surface Cu(0) than CuFe 2 O 4 -CP contained, which was in agreement with the diffraction peak intensities in the XRD patterns. Figure 8B shows that Fe(III) (2p 3/2 712.2 eV, 2p 1/2 725.9 eV) and Fe(II) (2p 3/2 710.4 eV, 2p 1/2 723.8 eV) coexisted on the surface of the three CuFe 2 O 4 samples (Li et al, 2019;Zhang et al, 2019). Obviously, the proportion of Fe(II) in CuFe 2 O 4 -SG and CuFe 2 O 4 -CP was much higher than that in CuFe 2 O 4 -ST.…”

“…For example, CoFe 2 O 4 was effective for activating PMS to degrade atrazine (Li et al, 2018). CuFe 2 O 4 and MnFe 2 O 4 could be applied as catalysts of PS for acetaminophen and phenol removal (Stoia et al, 2017;Zhang et al, 2019). Further, in combination with PS, ZnFe 2 O 4 exhibited good photocatalytic performance in the degradation of Orange II (Cai et al, 2016).…”

Polyaniline coated hematite sand supported on graphene oxide (HS@PANI‐GO) as a new magnetic material for advanced catalytic oxidation based on sulfate radicals: optimization using response surface methodology

“…Among these AOPs are, photocatalysis, electrocatalysis, photo‐electrocatalysis, electro‐Fenton, Fenton, peroxicoagulation, photo‐Fenton, sono‐Fenton, sonochemical methods, hydrodynamic cavitation, zero valent metals based AOPs, and oxidation processes based on the use of radicals (SO 4 −• , OH • ) . However, the oxidation by the radicals of sulfate SO 4 −• attracted a lot of attention because of the high oxidation potential that is expected at 2.01 V compared to others radicals . In addition, the high stability and the low cost of these radicals make this process interesting from an environmental and economical point of view .…”