Study On Fenton-like Catalyst Of Mesoporous Ferromanganese Oxide And Its Catalisis Degration Performance Of RhB

The large discharge and hazardous of dye wastewater have attracted people’s attention.Fenton method has been considered as an efficient way to degrade dye wastewater.However,traditional and even existing Fenton-like technologies have some limitations.In recent years,Transition metal oxides represented by manganese oxides have been widely studied,and their abundant valence state and high activation properties are considered as promising Fenton-like catalysts.In this paper,disordered and ordered mesoporous manganese dioxide（U-MnO₂ and M-MnO₂）was prepared by hard template method,and its removal efficiency of rhodamine B（RhB）simulated organic dye wastewater and adsorption performance of inorganic heavy metal ions were studied.In the same way,the disordered and ordered mesoporous ferro-manganese catalysts（U-MnFe_xO_y,M-MnFe_xO_y）were prepared to study their degradation activities in RhB dye wastewater,and to explore the influence of salt ions are represented by Cl^-1,SO₄^2-on the degradation activities in wastewater.The details are as follows:（1）In the presence of ethanol solution,manganese nitrate was impregnated into SBA-15template to prepare ordered mesoporous material M-MnO₂.On this basis,the disordered mesoporous material U-MnO₂ was prepared by adding ammonia.Study the removal effect of U-MnO₂ and M-MnO₂ on RhB which was used as a simulated organic wastewater.The adsorption of U-MnO₂ and M-MnO₂ on heavy metal ions was studied.The results showed that the specific surface area of U-MnO₂ was larger and the adsorption of RhB was better.The proportion of oxygen in M-MnO₂ lattice is larger,which means that the material is rich in oxygen vacancies and has better catalytic performance.The adsorption performance of M-MnO₂ to heavy metal ions represented by Cu²⁺and Cr⁶⁺is better,which is about twice that of U-MnO₂ under the same condition.（2）U-MnFe_x O_y and M-MnFe_xO_y were prepared with manganese nitrate and iron nitrate as precursors by hard template method,and their degradation performance of RhB simulated dye wastewater was studied.The results showed that U-MnFe_xO_y has a higher specific surface area of 279.9408 m²·g^-1,more than twice as high as M-MnFe_xO_y,which resulted in higher adsorption rate of RhB.The catalytic activity of M-MnFe_xO_y was higher than U-MnFe_xO_y,and the total removal rate was up to 99%.After monitoring the precipitated Fe²⁺and total iron in the degradation process,it was found that the precipitated Fe³⁺was 0.1 mg·L^-1 and 0.25mg·L^-1,respectively.Fe³⁺was reduced to Fe²⁺and formed a recycling system with Mn⁴⁺and Mn³⁺,so that the recycling efficiency of the catalyst was stable at a high level.（3）In order to further optimize the influence of doping ratio of manganese and iron on M-MnFe_xO_y structure and performance.Change the doping ratio of manganese and iron different doping ratios M-MnFe_xO_y（1:0.1;1:0.4;1:0.5;1:0.6;1:0.8）were prepared,,and study its effect on the structure and RhB degradation of this series of catalysts.With the increase of iron ion doping,the proportion between lattice oxygen and surface hydroxyl oxygen,Mn⁴⁺and Mn³⁺rose first and then decreased,reaching the highest when the proportion was 1:0.5.The catalytic activity of RhB was also highest in M-MnFe_xO_y（1:0.5）.It was found that the proportion of lattice oxygen and surface hydroxyl oxygen,Mn⁴⁺and Mn³⁺was the main factor affecting catalytic performance.