O₃ And O₃/H₂O₂ Oxidative Treatment Of TNT Red-Water In A Rotating Packed Bed

According to the literatures, the various techniques of TNT red-water treatment have been summarized, in which the ozone oxidation technology was better application prospect than other methods. But the mass transfer efficiency of ozone oxidative treatment wastewater was limited owing to its low solubility in water. The rotating packed bed as new intensified gas-liquid reaction device was proposed, which can meliorate ozone oxidation efficiency and save energy.Experiments on the removal efficiency of COD were carried out in different high gravity factor, pH value, molar ratio of H₂O₂ to O₃, liquid flow rate and so on with O₃ and O₃/H₂O₂ oxidative treatments. The results indicate that the removal efficiency of COD increases with increasing high gravity factorβ. And, the effect ofβon the removal efficiency of COD in red-water increases with increasing initial pH value of red-water. However this effect is not obvious as high gravity factor is higher than 100. The effect of initial pH value of red-water on the removal efficiency of COD is obvious. The optimum pH value is 11. The optimum molar ratio of H₂O₂ to O₃ changes between 0.5 and 1.0 with initial pH value. When initial pH value is 7.4, the optimum molar ratio of H₂O₂ to O₃ is about 1. When initial pH value is 10, the optimum molar ratio of H₂O₂ to O₃ is about 0.7. When initial pH value is 11, the optimum molar ratio of H₂O₂ to O₃ is about 0.5. The trend of the removal efficiency of COD increases with increasing liquid flow will be not obvious as pH value increasing. When liquid flow exceeds 100L/h, the removal efficiency of COD will decrease sharply.Under the condition of optimum technological parameters, the contacting model of physical ozone absorption by vitriol solution was put up. On this basis, the contacting model of chemical ozone absorption by TNT alkaline wastewater was established through the introduction of the enhancement factors in ozone absorption. The dates were fit by using the second order exponential decay, and the similarity coefficient is 99.841%. The results indicate that the mass-transfer coefficient of the physical absorption k0LAae is 0.0191s^-1; the mass-transfer coefficient of the chemical absorption kLAae reaches 0.258s^-1 at the beginning of the reaction, and then decreases with increase of the oxidation time, trending to 0.0191s^-1. This research provides guide in further study and industrialized application.Comparing with the self-made aerated mixer, the time of O₃ oxidation treatment of TNT red-water is reduced 38.6%, the cost of water treatment is reduced 21.97%; and, the time of O₃/H₂O₂ oxidation treatment of TNT red-water can be saved 50%, the cost of water treatment can be saved 42.41% , respectively.