Study On The Degradation Of Phenol Wastewater Enhanced By Microwave And Spiral Cutting

Organic wastewater is one of the big sources of pollution in industry,higher criterions have been set for the discharge of industrial organic wastewater with the advancement of ecological civilization construction in China.There are various new types of organic wastewater treatment technologies,microwave-assisted wastewater treatment is one of them.Because the microwave has the characteristics of rapid heating and activation energy reduced,it has broad outlook in the field of organic wastewater treatment.This paper studied the degradation of phenol by microwave-assisted Fenton oxidation and ozone oxidation under different process parameters,which took phenol wastewater simulated as the test materials.The main research contents were as follows:1.The effects of microwave-assisted Fenton reaction on the degradation of phenol wastewater were studied using single factor and response surface optimization methods.Also,the effects of phenol degradation under conventional Fenton reaction and microwave-assisted conditions were comparatively studied.The experimental results showed that microwave could accelerate the degradation rate of phenol and reduced the amount of Fe2+ significantly,and according to the results of regression analysis,the optimum process parameters were: microwave power density 1 W/ml,5 ml 0.02 mol/L Fe2+ addition and reaction time 426 s.Under this condition,the degradation rate of phenol was up to 93.91%.2.The mass transfer of ozone in water under three different modes were compared,including conventional aeration,recirculating gas-liquid mixing and static spiral cutting.The results showed that ozone mass transfer was enhanced in water by a novel type of static spiral cutting device,and the ozone concentration reaches to 12 mg/L in waterand the ozone mass transfer coefficient was as high as 0.2083 min-1 after 9 minwhich was 3.21 times as the conventional aeration method at the same conditions.It has been demonstrated that the use of a static spiral cutting device could enhance the mass transfer of ozone in water significantly.3.A gas-liquid flow chemical reaction system was built by combined the microwave reactor and static spiral cutter,including an ozone generator,a gas-liquid mixer,and a microwave radiation,which can be achieved the continuous circulation of reactants and improved the reaction efficiency.The ozone degrading phenol wastewater were studied with single-factor and response surface method by coupling of microwave and static spiral cutting.Also,the effects of phenol degradation under different conditions were comparatively studied.The experimental results showed that the cavity core structure of the static spiral cutter could increase the degradation rate of phenol significantly,the degradation rate of phenol reached to 97.09% in 12 min under certain conditions.The process parameters was optimized as following: gas flow rate 2.2 L/min,liquid flow rate 6.4 L/min,and microwave power density 62 W/L.Under this condition,the degradation rate of phenol was up to 98.47%.This paper provided a novel microwave-assisted reaction system suitable for gas-liquid reaction.Based on the experiment of two kinds of microwave-assisted organic oxidation processes,it was proved that the current technology coupled the microwave and helical cutting has the advantages of high reaction efficiency and cleaning.It was an environmentally friendly and energy-saving method for organic wastewater treatment.