| The heterogeneous Fenton technology is an advanced oxidation water treatment technology with potential application prospects,and an efficient and stable catalyst is the key to the further development and application of this technology.The multi-component composite metal oxides can accelerate interfacial electron transfer through the synergy between different metals,promote the decomposition of hydrogen peroxide to generate active radicals,and improve the removal efficiency of organic pollutants.Therefore,in this paper,metal-modified zinc ferrite and iron-copper composite oxides were synthesized by a hydrothermal method.The Fenton-like catalytic properties of the above materials for acidic orange II were studied,and its possible catalytic mechanism was explored.The study is as follows:?1?Preparation of copper-modified zinc ferrite and its photocatalytic and Fenton-like catalytic propertiesA series of copper-modified zinc ferrite were prepared by a hydrothermal method using ferric nitrate?Fe?NO3?3·9H2O?,zinc nitrate?Zn?NO3?2·6H2O?and nitric acid?Cu?NO3?2·3H2O?as raw materials.The photocatalysis and Fenton-like properties of the catalyst were investigated using acid orange II as the target pollutant.It was found that the introduction of copper greatly improved the catalytic performance of zinc ferrite,and the catalyst with the zinc:copper ratio of 7:3 had the highest activity.In addition,we further studied the main active species for acid Orange II degradation and the major active sites for H2O2decomposition.The results show that in the photocatalytic reaction,zinc ferrite?ZnFe2O4?and cuprous oxide?Cu2O?form a heterojunction,which promotes the separation of photogenerated electrons and holes,and holes are the main active species that degrade acidic orange II.In the Fenton-like reaction,acidic orange II is mainly degraded by superoxide radical?·O2-?,which is due to that Cu2+has a stronger oxidizing ability on the surface of the catalyst and reacts more easily with hydrogen peroxide?H2O2?generate·O2-.?2?Preparation of Cobalt Modified Ferrite and Its Fenton-like PropertiesCobalt-modified zinc ferrite was synthesized by a hydrothermal method using ferric nitrate?Fe?NO3?3·9H2O?,zinc nitrate?Zn?NO3?2·6H2O?and cobalt nitrate?Co?NO3?2·6H2O?as raw materials.catalyst.X-ray diffraction?XRD?,S-4800 cold field emission scanning electron microscopy?SEM?and automatic surface porosity analyzer?BET?were used to characterize the morphology and structure of the samples.Acid orange II was used as a simulated contaminant.The catalytic performance of the catalyst under different conditions was studied.The results show that the activity of the catalyst decreased but the magnetic properties increased with the increase of cobalt content.At pH=6,the catalyst dosage of 0.5 g/L and the H2O2 amount of 10 mmol/L,the highest degradation efficiency of acid orange II was obtained..?3?Preparation of Fe-Cu Composite Oxides and Their Fenton-like Catalytic PropertiesThe composite metal oxides with different iron:copper ratios were synthesized by a hydrothermal method using ferric nitrate?Fe?NO3?3·9H2O?and copper nitrate?Cu?NO3?2·3H2O?as raw materials,and their Fenton-like catalytic performance was studied.The results show that the degree of crystallization of the prepared catalyst increased with the increase of copper content,and the catalyst with the iron-copper ratio of 1:1 exhibited the highest activity.Through investigation of its mechanism,it was found that the main active species of this catalyst for the degradation of acid Orange II was·O2-. |
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