The Application Of A Novel Ferrite Coated Zeolite In Pilot Plant Of Microwave Assisted Uv Device Treating Methyl Violet Wastewater

In recent years, the dye wastewater has caused the people’s extensive concern, triphenlmethane dyes is becoming the third largest most widely used dyes. As the advanced oxidation technology (AOP),photo heterogeneous Fenton technology have been widely used for the degradation of refractory compounds in the laboratory scale, Since Horikoshi find that MW fields could accelerate the degradation of refractory compounds, researchers have got achievements in the degradation mechanism and their efficiency. We develop a novel technology Microwave assisted photo heterogeneous Fenton (MPHF) systems to treat dye wastewater.An efficient ferrite loaded zeolite (FZ) was successfully developed as a heterogeneous catalyst to degrade methyl violet MEV in MPHF systems. The degradation efficiency of MEV,the reaction mechanism of MEV and the catalytic property of the catalyst in MPHF systems was investigated.(1) SEM and TEM/HRTEM were employed to examine the morphology and intrinsic crystal structures of the as-synthesized catalyst, the Fe3O4nanoparticles are scattered in small clusters on the zeolite,diameters of the clusters range froml μm-2μm.The peaks in XRD spectrum appeared at30°,35.5°,37°,43°,53.5°correspond to cubic Fe3O4(220),Fe3O4(311),Fe3O4(222),Fe3O4(400),Fe3O4(422) diffraction peaks, respectively. About15.6%Fe2+exists in zeolite mainly through ion exchange with Na+,and the catalyst has good dispersion property, strong magnetism and convenient recovery.(2) The degradation efficiency of MEV in different systems was investigated.The degradation efficiency of MEV was99.97%in30min degradation time in the MPHF system when the conditions were [MEV]=20mg/L,[FZ-1]=0.4g/L,[H2O2]=5.28mmol/L,pH=7.7±0.1.And the degradation efficiency of MEV were80%,78%,13%,14%respectly in the Microwave assisted UV/H2O2system,Microwave assisted heterogeneous Fenton system,Microwave assisted H2O2system and heterogeneous Fenton system under same conditions.The best dosing quantity of FZ-1is0.4g/L, the best concentration of H2O2was5.28mmol/L, and a wide range of pH is suited in the MPHF system. The MEV degradation performance on the reused catalyst showed a slight difference with the first oxidation cycle. The degradation efficiency of MEV was above90%for the fifth oxidation cycle. The homogeneous reaction by the leached iron species from the catalyst just made a very small contribution to the MEV degradation. The heterogeneous Fenton-like oxidation reaction occurred on the catalyst surface was the main pathway of the MEV degradation.(3) The degradation mechanism of MEV by FZ-1catalysis in the MPHF system was discussed on the basis of analysis of the intermediates and proven by the theoretical calculation of frontier electron densities.(4) The degradation efficiency of MEV simulated the dye wastewater was investigated. In the MPHF system/the degradation efficiency of MEV was90%in6min degradation time,and the degradation efficiency of COD was54.5%in3min degradation time when the conditions were [MEV]=500mg/L,[FZ-1]=5.0g/L,[H2O2]=80mmol/L,pH=7.45±0.1.