Study On Oxidation Of Textile Wastewater With O₃ And O₃/H₂O₂ Strengthened By Pressurized Dissolved Gas

In order to improve the ozone mass transfer and utilization efficiency of ozone oxidation technology,the paper made a research on the treatment of refractory azo dye reactive brilliant red X-3B simulated wastewater and the textile biochemical effluent,in which the O₃,O₃/H₂O₂oxidation system is strengthened by pressurized dissolved gas.The specific research content is as follows:?1?The degradation of reactive brilliant red under the ozonation process strengthened by pressurized dissolved gas was studied.The factors of operating parameters affecting the removal rate of chroma and COD_Cr such as device pressure,reaction time,initial pH,gas-liquid ratio and ozone dosage were examined,furthermore,the degradation reaction kinetics and process were also explored.It is indicated that the pressurized dissolved gas technology oxidized dye molecule effectively,and the removal rate of COD_Cr increased by 30.3%and the complete decolorization time is shortened by 15 min,respectively,in 30 minutes,comparing with that by the atmospheric pressure bubbling aeration.The increase of reactor pressure,the extension of reaction time and the increase of ozone dosage were favorable to the removal rate of COD_Cr and chroma of wastewater,however,the COD_Cr removal and decolorization rate were less affected by the initial pH and gas-liquid ratio.In the case of pressurized dissolved gas,the degradation process of reactive brilliant red accords with the apparent first-order reaction kinetics equation,and the apparent rate constant are positively correlated with the dosage of ozone and device pressure.In addition,the degradation of dye molecules under the pressurized dissolved gas reaction system is a gradual oxidation process,and the azo structure is first destroyed.As the reaction proceeds,the structures such as benzene ring,triazine ring,naphthalene ring and-SO₃Na are destroyed and decomposed into small molecular substances.?2?The oxidation of reactive brilliant red with O₃/H₂O₂ process intensified by pressurized dissolved gas was studied.Experiments on the degradation of reactive brilliant red were carried out in different H₂O₂ dosage,reactor pressure,initial pH value,initial dye concentration and O₃dosage,besides,the degradation process of dye molecular was also analyzed.The results show that the oxidative degradation efficiency of reactive brilliant red is greatly improved in the O₃/H₂O₂oxidation system compared to the O₃ oxidation system alone,but it is important to control the appropriate H₂O₂ concentration.If the concentration is excessive or derisory,the oxidative degradation efficiency will be weakened.The increase of reactor pressure and ozone dosage are beneficial to the oxidation of dye molecules,but the increase of dye concentration has an adverse effect on the degradation of wastewater,and the initial pH value has little effect on the degradation efficiency of reactive brilliant red.The pressurized dissolved gas enhanced O₃/H₂O₂ oxidation system has achieved great treatment effect on the reactive brilliant red wastewater,the azo bond,benzene ring,triazine ring,naphthalene ring and-SO₃Na of the dye were oxidatively degraded.?3?Under the O₃ and O₃/H₂O₂ oxidation system enhanced by pressurized dissolved gas,the degradation of textile biochemical effluent was studied.The removal rates of UV₂₅₄ and COD_Cr in the wastewater were investigated,and the three-dimensional fluorescence spectra of the water samples were also analyzed.The results show that the O₃ oxidation system enhanced by pressurized dissolved gas has great oxidation treatment effect on the textile biochemical effluent,and the UV₂₅₄ and COD_Cr removal rates are 74.7%and 40.9%,respectively.Under the suitable hydrogen peroxide concentration,The treatment effect of the O₃/H₂O₂ oxidation system on biochemical effluent can be greatly improved.In addition,there are some differences in the oxidative degradation pathways of organic matter in the biochemical effluent under the O₃ and O₃/H₂O₂ oxidation systems.