Treatment Of Sulfide Wastewater By Air Oxidation Based On Manganese Supported Catalyst

Air oxidation,as a very promising method of advanced oxidation technology,can be used in the desulfurization treatment of industrial sulfur containing wastewater by oxygen as oxidant,which has the advantages of simple application process,low cost,green environmental protection and so on.But individual air oxidation also has some problems,such as low efficiency of oxygen.The design and use of heterogeneous supported catalyst can not only improve the utilization of oxygen in water,improve the efficiency of desulfurization,but also avoid the production of metal ions of the homogeneous catalyst.MnO2/?-Al2O3 heterogeneous catalysts were prepared by wet impregnation method and were characterized by X-ray Diffraction(XRD),scanning Electron Microscope(SEM),nitrogen adsorption,Fourier Transform Infrared Spectrometer(FT-IR),and temperature programmed desorption of ammonia(NH3-TPD).In this paper,we take ?-Al2O3 as carrier,Mn(NO3)2·4H2O as precursor,the loading of Mn is 10%,and calcination temperature is 450?.For the simulated sulfur containing wastewater with initial concentration of 1000ppm,the reaction temperature is 25?,the air flow is 0.6 L/min and the amount of catalyst is 1 g/L,and the desulfurization degree is 80.89%when the reaction is 4.5 h.Based on the MnO2/?-Al2O3 catalysts a small amount of metal elements(Fe?Mg?Cu?Zn)were doped in it using impregnation by step to improve its catalytic performance,stability and reusability.Related characteration and evaluation of activity were also made in the experiments.Under the same reaction conditions,copper is used as precursor,the calcination temperature is 450?,and the catalyst of 1%Cu metal modification has the best catalytic activity.After reaction 2h,the desulfurization degree is about 90.54%.The catalysts were characterized by XPS before and after the reaction.It was proved that the rich Mn4+on the surface of the catalyst and the adsorbed oxygen species(Oads)on the surface were beneficial to the catalytic reaction.The realization of the catalytic process benefited from the formation of the Mn4+/Mn3+redox pair and opened up a new electron transfer path.In the process of reaction,the changes in the concentration of sulfur and other ions in the system are investigated.The results show that the S2-is oxidized to S2O32-in the first process of treating sulfur wastewater by Cu-MnO2/?-Al2O3 catalyst,and the final product of the reaction is SO42-.