Study On The Heterogeneous Activation Of Persulfate For The Oxidation Degradation Of Golden Orange ? Using Mn₃O₄-CeO₂/Three Dimentional Graphenen

In recent years,the treatment of dyeing wastewater has been imminent with the rapid development of dyestuff industry.Among the treatment techiques,the emerging heterogeneous persulfate advanced oxidation technology have a good application prospect in the filed of dyeing wastewater treatment due to its advantages of high efficiency,no secondary pollution,low treatment cost and easy management.The Considering that,not only three-dimensional graphene?3D GN?has large specific surface area and unique three-dimensional pore structure,and is therefore an excellent support material,but also 3D GN as the carrier of the catalyst in the persulfate oxidation technology has been rarely used,this paper mainly includes the following research contents:?1?Heterogeneous catalysts for activation of persulfate were prepared by hydrothermal reduction method using transition metal oxides Mn₃O₄ with higher catalytic activity and rare earth oxide CeO₂ riched in our country as active components and 3D GN as the carrier.Through changing the ratio of the manganese and cerium salt proportion,a series of Mn₃O₄-CeO₂/3D GN catalyst with various ratios and different catalytic performance were obtained.The physical properties,chemical structure and composition of the prepared catalysts were characterized by various analysis techniques.The catalytic activity and stability of the supported manganese-cerium double metal oxide catalysts prepared under different ratios were investigated in detail.Combined with the results of free radical quenching experiment,the relationship of the structure,properties and catalytic performance was analyzed.The results showed that the optimal ratio of manganese-cerium double metal oxide supported catalyst was 30% Mn₃O₄: 10% CeO₂.30%.30%Mn₃O₄-10% CeO₂/3D GN exhibited a unique interconnected three-dimensional network structure,Mn₃O₄ and CeO₂ nanoparticles were uniformly dispersed in the graphene sheet.The specific surface area and pHzpc of 30%Mn₃O₄-10% CeO₂/3D GN was 250.43m²/g and 7.56,respectively.Moreover,the existence of Mn²⁺ in Mn₃O₄,could overcome the inefficiencies of Mn3+,Mn4+,and Ce4+ in catalyzing the persulfate to generate sulfate radicals.It was the necessary condition to ensure the manganese cerium double metal oxide catalyst with higher catalytic activity.The presence of a small amount of Ce could increase the hydroxyl group content of the catalyst surface,and further improve its catalytic activity.The strong Mn-Ce-O bonding interaction could effectively improve the stability of the catalyst.?2?The effect of catalyst dosage,persulfate dosage,initial concentration of Golden Orange ?,initial pH of solution and temperature on the degradation of Golden Orange ? wastewater by persulfate oxidation system catalyzed by Mn₃O₄-CeO₂/3D GN was investigated by single factor experiment.The results showed that the dosage of oxidant and catalyst has a significantly impact on the oxidative degradation of Golden Orange ?.The decolorization of Golden Orange ? was fitted by a first-order kinetic equation.The influence of temperature followed the Arrhenius trend,and the degradation effect was best at pH=6.The decolorization activation energy?Ea?of the persulfate oxidation system catalyzed by Mn₃O₄-CeO₂/3D GN was only 17.001 k J/mol,which was smaller than that of system catalyed by Mn₃O₄/3D GN.Moreover,the activation entropy of the persulfate oxidation system catalyzed by Mn₃O₄-CeO₂/3D GN was less than zero,which was beneficial to improve the reaction efficiency.?3?The effects of common anions in wastewater on degradation of Golden Orange ? dye wastewater by persulfate oxidation system catalyzed by Mn₃O₄-CeO₂/3D GN were also studied in detail.The experimental results showed that H₂PO₄^-could promote the reaction to a certain extent,HCO₃^-could inhibit the reaction to a certain extent,NO₃^-had little effect on the reaction,and Cl^-had a serious inhibitory effect on the reaction.