Study On The Preparation Of Microwave Catalyst And Microwave Catalytic Oxidation Degradation Of Organic Wastewater

With the development of economy and the burden of environment are increasingly heavy,especially the water environment.The organic wastewater is deep color,it is difficult to be decomposed by biochemical method and has complex ingredient.These organic pollutants which inflow into the water,it is not only seriously polluted the water resource,but also has a potential risk to human health.From the two aspects of environment and human health,it is necessary to eliminate them from the organic wastewater.So it is very urgent to develop a kind of high efficiency and economic method to treat organic wastewater.Microwave technology is a new type of technology in the treating of wastewater.In recent years,it has received more and more attentions.There are a lot of papers which reported that use microwave technology to treat wastewater,such as microwave-assisted photocatalytic oxidation,microwave enhanced inorganic oxidizer oxidation,but these methods are still not out of the traditional oxidation technology.In this study,the microwave catalytic technology was utilized to catalyze oxidation degradation of organic wastewater.Microwave catalytic oxidation that is under the microwave irradiation can produce hydroxyl radical on the surface of catalyst,these oxidation groups oxidize the substrate.The key for microwave catalytic oxidation is the development and preparation of the microwave catalyst.The microwave catalyst has its unique nature,it must have a strong microwave absorbing capacity,porous structure,and have OH groups on the surface of the structure.These microwave catalysts such as adsorbent,semiconductor,ferromagnetic metal,transition metal oxides,and ferrite.The microwave catalytic oxidation can accelerate the reaction rate and shorten the reaction time,improve efficiency and cost savings.Microwave catalyst TiO2-AC was prepared by sol-gel-load method,and MgFe2O4-Fe2O3 was prepared by co-precipitation method,they were characterized by XRD,IR,SEM,BET detection analyzer.Under the microwave catalyze,oxidation degradation of organic wastewater respectively.Choose azo compound methyl orange and triphenylmethane compound crystal violet as the target substrates.Investigated the concentration of catalyst,microwave irradiation time,microwave power,the initial concentration of organic wastewater and different catalyst for the influence of the degradation rate.Microwave catalytic oxidation degradation of methyl orange wastewater,microwave power for 600 W,microwave radiation time for 12 min,the dosage of Ti02-AC for 18 g/L,methyl orange concentration of 50 mg/L?250 mg/L,degradation rate was 84.7%?99.1%,when methyl orange concentration is 250 mg/L,under the same conditions,to extend the time of microwave catalytic to 28 min,the decomposition rate can reach to 99.3%.Microwave catalytic oxidation degradation of crystal violet wastewater,microwave power for 800 W,microwave radiation time for 6 min,the amount of catalyst for 1 g/L,crystal violet concentration for 100 mg/L?500 mg/L,degradation rate was 96%?99.4%.We explored the mechanism of the microwave catalytic action,which is under the microwave irradiation microwave catalysts can absorb it and in the microwave electromagnetic field can result in microwave catalytic reaction.In an especial reaction environment,the microwave catalyst under microwave irradiation will produce strong oxidizing·OH radicals,the generated · OH radical can oxidize substrate.Microwave catalysis mechanism used in the degradation of organic compounds of methyl orange and crystal violet,proved by experiments which can not completely oxidize and degrade organic matter,but completely mineralize it to CO2 and H20.By analyzed the reaction kinetic data,we know that the reactions of microwave catalytic oxidation degradation of organic wastewater methyl orange and crystal violet are first order reaction.