Synthesis,Characterization And Catalytic Activities Of CuFe₂O₄/MWCNTs Composite Material

Sulfate radical(SO₄^·-)based advanced oxidation technologies have exhibited a good application prospect in wastewater treatment.Oxidants such as persulfate?PS?and peroxymonosulfate?PMS?are able to generate highly oxidative sulfate radicals?standard potential 2.5-3.1 V?,much more oxidative than hydroxyl radicals?2.2-2.7 V?.PS and PMS are bench-stable and highly compatible with inorganic salts such as carbonate and chloride in practical aqueous environment.Copper ferrite?CuFe₂O₄?has been widely reported as a heterogeneous catalyst for efficient activation of PMS.However,the activation of PS by CuFe₂O₄has been rarely studied.On the other hand,to further enhance the catalytic activity,the synergetic effect between CuFe₂O₄ and other co-catalyst needs to be explored.In this study,the catalytic activation of PS and PMS by CuFe₂O₄ based catalysts,as well as degradation of two classic environmental endocrine disruptors are diethyl phthalate?DEP?and 2-Phenylbenzimidazole-5-sulfonic acid?PBSA?.?1?Sol-gel combustion method was applied to synthesize CuFe₂O₄ decorated multi-walled carbon nanotubes magnetic nanoparticles?CuFe₂O₄/MWCNTs MNPs?for DEP removal.The catalyst was fully characterized by scanning electron microscope?SEM?,transmission electron microscope?TEM?,Brunauer-Emmett-Teller?BET?surface area analysis,Fourier transform infrared spectroscopy?FT-IR?,X-ray diffraction?XRD?,and X-ray photoelectron spectroscopy?XPS?.The Experimental conditions,such as catalyst loading,PS concentrations,temperature and pH,were fine-tuned to investigated the catalytic degradation process of DEP by PS.Moreover,the CuFe₂O₄/MWCNTs MNPs were proved to be highly catalytically active,stable and recyclable in DEP removal.Especially,negligible leaching of metal ions from reused CuFe₂O₄/MWCNTs was detected by atomic absorption?AAS?,indicating its resistance to oxidation.In the presence of PS,CuFe₂O₄/MWCNTs accelerating the generation of ·OH and SO₄^·-was confirmed by electron paramagnetic resonance?EPR?analysis.Besides,the quenching experiments further verified the catalytic reaction was predominated by SO₄^·-.Finally,the degradation intermediates were identified and the degradation pathways were proposed.?2?Based on rational design,a nitrogen and sulfur co-doped MWCNTs loaded CuFe₂O₄?NS-CNTs/CuFe₂O₄?catalyst was synthesized using co-precipitation method for the degradation of PBSA?a typical sunscreen addition?.The composite nature of the catalyst was observed using SEM and TEM.XRD,XPS and FT-IR further revealed the crystal structure,the presence of desired elements,and functional groups,respectively.Next,we studied the kinetics,pathways and mechanisms of catalytic degradation of PBSA with NS-CNTs/CuFe₂O₄ activated PMS in solution.The catalyst showed high catalytic activity,stability and reusability in PBSA removal.Combining the EPR analysis and the results of quenching experiments,SO₄^·-was suggested to be the main active species in the activation of PMS by NS-CNTs/CuFe₂O₄.In addition,the synergistic effect between CuFe₂O₄ and NS-CNTs was proposed in PMS activation.Finally,eight degradation intermediates of PBSA were identified by liquid chromatography mass spectrometry?LC-MS?,and degradation pathways were therefore proposed.Overall,this study provides insights of PBSA removal by NS-CNTs/CuFe₂O₄ activated PMS at ambient temperature.