Characteristics Of Ozone Microbubble Catalytic Oxidation Treatment Of Dye Wastewater

The microbubble aeration technology was applied for ozone catalytic oxidation treatment of the acid red 3R dye wastewater in this study.The purposes of this study were to provide a new treatment approach for the treatment of dye wastewater and to improve advanced oxidation technology.The ozone gas liquid mass transfer characteristics were investigated using ozone microbubble,and the characteristics and the influencing factors of ozone microbubble catalytic oxidation of acid red 3R wastewater were studied.Moreover,reaction mechanism and degradation pathway of acid red 3R was studied preliminarily.The results show that the addition of activated carbon could improve the gas-liquid mass transfer rate of ozone.The mass transfer coefficient of ozone was 2 times that of microbubble aeration only when the dosage of activated carbon was 2 g × L^-1,and the dissolved ozone decomposition coefficient was 1.2 times that of the traditional bubble system,which would be better for ·OH generation.The investigation of characteristics of the ozone microbubbles catalytic oxidation treatment of acid red 3R wastewater indicated that the optimal activated carbon dosage was 2 g×L^-1 for acid red 3R wasteater treatment.Under this condition,TOC removal rate could reach up to 88.2%.Then the reaction conditions were changed to investigate the effects of some influence factors on ozone microbubble catalytic oxidation of acid red 3R wastewater.The results showed that pH had significant influence on mineralization of acid red 3R,and TOC removal was better under strong acid condition,which could reach 87%.In addition,the treatment performance and reaction rate could be improved when the dosage of ozone was increased and the initial acid red 3R concentration was reduced.When sodium carbonate was added into the reaction system as ·OH scavenger,the TOC removal rate decreased significantly,indicating that there was a ·OH oxidation reaction in ozone microbubble catalytic oxidation of acid red 3R wastewater.Then the by-products of ozone microbubble catalytic oxidation of acid red 3R wastewater were tested using liquid chromatography-mass spectrometry?LC-MS?after 30 min and 90 min treatment.The analysis of?LC-MS?indicated that the main degradation pathway of acid red 3R was azo degradation mechanism,and then the macromolecule was gradually oxidized into small molecule organic acid,and finally degraded into H₂Oand CO₂2.