| In this paper,the advanced treatment of biological pretreated coking wastewater by impinging stream-hydrodynamic cavitation and hybrid treatment between impinging stream-hydrodynamic cavitation and Fenton,and all effect factors of the two technologies were investigated.The degradation mechanism of two advanced treatments was studied preliminary by quantitative analysis of hydroxyl free radical and effect of hydroxyl free radical scavenger,UV-Vis absorption spectrometry（UV-Vis）and gas chromatography/mass spectrometry（GC/MS）analysis showed that the variation of organic molecular structure and degradation products.The main research contents and results of this paper are as follows:（1）Advanced treatment by impinging stream-hydrodynamic cavitation is effective for organic pollutant removal efficiency,reducing initial p H,and increasing reaction temperature,inlet pressure,inlet angel,outlet angel and throat length appropriately are contributed to improving organic pollutant removal efficiency.At the experimental conditions of reaction temperature of 40℃,cycle time of 60 min,initial p H of 2,inlet pressure of 0.5MPa,inlet angel of 76°,outlet angel of 76°,and throat length of 10mm,UV254,UV260,Vis380 and COD removal effinciency are up to 55.34%,56.18%,62.46%and 30.25%,respectively.The Response Optimization of operating conditions shows that initial p H and reaction temperature have significantly effect on UV254 removal efficiency.（2）Organic pollutant removal efficiency is higher after hybrid treatment by impinging stream-hydrodynamic cavitation and Fenton.Reducing initial p H,increasing inlet pressure,and increasing reaction temperature,H2O2 concentration and Fe2+concentration appropriately,are contributed to improving organic pollutant removal efficiency.At the experimental conditions of reaction temperature of 40℃,cycle time of15min,initial p H of 7,inlet pressure of 0.1MPa,H2O2 concentration of 12mmol/L and Fe2+concentration of 3mmol/L,UV254,UV260,Vis380 and COD removal efficiency are up to 86.17%,88.88%,96.45%and 33.40%,respectively.The The Response Optimization shows that H2O2 concentration and Fe2+concentration have significantly effect on UV254removal efficiency,significant of initial p H is ordinarily.（3）Studies find that the removal efficiencies of organic pollutant are decreased with increasing of hydroxyl free radical scavenger,element anlysis show that a certain amount of C,H,and Fe are found in sediment,which speculates the degradation mechanism of two advanced treatments contained free radical oxidation and flocculation,and total nitrogen content（TN）is satisfied to indirect emissions standards of Coking Chemical Industrial Pollutants Emission Standards（GB16171-2012）.UV-Vis and GC/MS analysis indicate that organic molecular structures have been broken badly by the hybrid treatment between impinging stream-hydrodynamic cavitation and Fenton,and the quantity and variety of organic molecular have been decreased observably after advanced treatment.In this paper,impingping stream-hydrodynamic cavitation compared with Fenton is used in advanced treatment of coking wastewater,it puts a new advanced treatment on degradation of refractory organic pollutant,and provides theoretical guidance and technical support for refractory organic wastewater,like coking wastewater. |
