Activation of persulfate by MMIOC for highly efficient degradation of rhodamine B

Abstract

Mesoporous magnetic iron oxide composites (MMIOCs) were successfully prepared using one-step evaporation induced self-assembly using an organic ferrocene surface active agent as the iron source, and innovatively studied as a potential alternative to mesoporous Co 3 O 4 for ammonium persulfate (PS) activation to generate active radicals. MMIOCs were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N 2 adsorption/desorption, transmission electron microscopy (TEM) and using a vibrating sample magnetometer (VSM). Among the different Fe x O y /PS systems tested, the MMIOC displayed the highest catalytic activity for PS activation, achieving almost complete degradation of 1 mM rhodamine B (RhB) within 120 minutes at 0.2 g L À1 catalyst and 40.0 mM PS. The superior catalytic performance of the MMIOC was ascribed to the combination of iron ions inlayed or embedded in the inner or outer surface, forming catalytically active sites and the magnetic mesoporous structure.Several factors played important roles in controlling the degradation of RhB. The equilibrium between Fe(II) and^Fe(III) for PS activation in solution ensured continuous generation of the hydroxyl and sulfate radicals, and the latter made the predominant contribution for RhB degradation. Considering its outstanding catalytic activity, excellent reusability and long-term stability, MMIOC could be an ideal catalyst for the degradation of RhB. These results provide an applied solution for disposing of toxic organic wastewater in a relatively available environment, and a scientific foundation for solving refractory organic contaminant related to environmental management.

Enhanced Activation of Persulfate by Meso-CoFe2O4/SiO2 with Ultrasonic Treatment for Degradation of Chlorpyrifos

“…47 Therefore, as shown in Figure 6, the dominant radical of this reaction should be the hydroxyl radical. Based on the results obtained and the literature, 45,48 the mechanism based on enhanced activation of persulfate by Meso-CoFe 2 O 4 /SiO 2 with ultrasonic treatment to degrade chlorpyrifos was proposed. Chief equations of reaction were as follows: 46 …”

“…Further, only 92.4% COD removal ratios in the OFE/PDS/US system was higher than 65% in the MMS/PS system. 48 The active component, mesoporous structure, and ultrasonic cavitation improved more effectively the surface reaction to mineralize the chlorpyrifos. 50,51 The concentration of various ions in the solution was determined by ion chromatography.…”

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

“…and H 2 O or OH − (Eqns (2)-(6)). 29,68,69 In addition, the synergistic interaction between PANI and HS favored the in situ recycling of iron ions Fe 2+ and Fe 3+ in the catalyst. In addition, PANI and GO have a large surface area, which promotes the adsorption of contaminants, as well as, persulfate ions, which allows a greater degradation of pollutants.…”

“…To overcome these disadvantages, advanced oxidation processes (AOPs) should be preferentially used. 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 .…”

“…Among these AOPs are, photocatalysis, [10][11][12] electrocatalysis, 13 photo-electrocatalysis, 14 electro-Fenton, [15][16][17][18] Fenton, 19,20 peroxicoagulation, 21,22 photo-Fenton, 23 sono-Fenton, 24 sonochemical methods, 25 hydrodynamic cavitation, 26 zero valent metals based AOPs, 27,28 and oxidation processes based on the use of radicals (SO 4 −• , OH • ). 29,30 However, the oxidation by the radicals…”