Catalytic Degradation Of Orange Ⅱ Dye Wastewater By Nickel-containin G Metal-based Materials And Its Mechanism

In this project,the performance of nickel-containing metal-based materials activated persulfate to degrade OrangeⅡaqueous solution was studied.Two kinds of nickel-containing materials,bimetallic oxides and trimetallic sulfides,were prepared in the experiment,which are denoted as NiO-CeO₂ and Ni₂Fe Sn S₄,respectively.The physicochemical properties such as crystal structure,morphology size,molecular structure and atomic valence state of the material were characterized before studying its degradation performance.The focus is to qualitatively explore the adsorption and degradation performance of the catalyst materials for the analytical liquid Orange Ⅱ.（1）The degradation of Orange Ⅱ by NiO-CeO₂/PSIn this experiment,NiO and CeO₂ composite metal oxides（NiO-CeO₂）were synthesized by sol-gel method,and the degradation system activated by persulfate（PS）assisted by visible light（Vis）was studied.The crystal phase composition of NiO-CeO₂ was detected by X-ray diffractometer（XRD）,and the morphology of NiO-CeO₂ was characterized by scanning electron microscope（SEM）.Valence.In the Vis/PS/NiO-CeO₂ system,the degradation rate using Orange Ⅱ at a concentration of 50 mg/L was as high as 90%within15 minutes,but increased to 99%within 60 minutes.Mechanistic studies show that the combination of NiO and CeO₂ generates more oxygen vacancies and activates persulfate to generate reactive oxygen species.In addition,the effects of visible light,persulfate concentration and p H were evaluated,and the results showed that the participation of visible light and persulfate could significantly improve the degradation efficiency of Orange Ⅱ,while p H had little effect on the degradation.Quenching experiments and ESR detection indicated that the degradation mechanism lies in the activation of persulfate to generate reactive species such as·O₂^-,·SO₄^-,·OH and ₁O².Furthermore,the recovery and reuse properties of NiO-CeO₂may lead to sustainable treatment of wastewater.In addition,we also explored the effect of NiO-CeO₂/PS system on some refractory organics,such as nitrobenzene（C₆H₅NO₂）,4-nitrophenol（C₆H₅NO₃）and p-chlorophenol（Cl C₆H₄OH）.CeO₂ has little selectivity for the degradation of pollutants,and its practical application is not limited.（2）The degradation of Orange Ⅱ by Ni₂Fe Sn S₄/Vis/PSIn this experiment,a novel metal sulfide material,Ni₂Fe Sn S₄,was used to degrade organic pollutants in a heterogeneous photocatalytic system.The morphology and composition of the material were verified by XRD,SEM and other characterization methods.In this study,it was concluded through the photocatalytic performance experiments of this material that Ni₂Fe Sn S₄ could completely degrade Orange Ⅱ within 45 minutes with the assistance of visible light and potassium persulfate with strong stability.Through XPS analysis,single metal control experiment and inhibition experiment,the degradation mechanism of pollutants was clarified.Visible light and catalyst materials activated potassium persulfate to generate various free radicals such as·O₂^-,·SO₄^-,·OH,etc.,which were harmful to pollutants.degradation plays a leading role.In addition,combined with practical applications,the effects of p H,organic matter and various anions on the catalytic degradation are discussed,and the experimental results are explained from a mechanistic point of view.